HK1212586B - Automated systems for powered cots - Google Patents

Description

Automatic system for bed with power device

Cross reference to related art

This application claims priority under 35u.s.c. § 119 to U.S. provisional application serial No.61/673,971, filed on 20/7/2012.

Technical Field

The present disclosure relates generally to automated systems, and in particular to automated systems for powered beds.

Background

Various emergency cot are put into use at present. These emergency cots are designed to transport and load obese patients into ambulances.

For example, manufactured by Ferno-Washington, Wimington, Ohio, USAThe bed is a manually actuated bed that can provide stability and support for a load of about 700 pounds (about 317.7 kg).The bed includes a patient support portion attached to a wheeled chassis. The wheeled undercarriage includes an X-frame geometry that is capable of transitioning between nine selectable positions. One recognized advantage of this bed design is that the X-shaped frame provides minimal bending and a low center of gravity at all selectable positions. Another recognized advantage of this bed design is that the selectable positions may provide better leverage for manually lifting and loading obese patients.

Another example of a bed designed for obese patients is powerflex + Powered Cot manufactured by Ferno-Washington corporation. Powerflex + Powered Cot includes a battery Powered actuator that can provide sufficient power to lift a load of about 700 pounds (about 317.5 kg). One recognized advantage of this cot design is that it can lift obese patients from a low position to a higher position, i.e., can reduce the need for an operator to lift the patient.

Another variation is a multi-purpose roll-in cot having a patient support stretcher removably attached to a wheeled chassis or transport device. When the patient support stretcher is removed from the transport device for individual use, the patient support stretcher may be moved back and forth horizontally on a set of wheels included. One recognized advantage of this cot design is that the stretcher can be rolled into an emergency vehicle alone, such as a station wagon, van, combination ambulance, airplane, or helicopter, where space and weight loss are a priority.

Another advantage of this bed design is that the split stretcher can be more easily transported over uneven terrain and away from locations where the entire bed cannot be used to transport patients. Examples of such beds can be found in U.S. patent nos. 4,037,871, 4,921,295 and international publication No. wo 01701611.

Although the aforementioned multi-purpose roll-in cots have been generally adapted for their intended use, they have not been satisfactory in all respects. For example, loading the aforementioned cot into an ambulance according to such a loading procedure requires at least one operator: the loading process requires at least one operator to support the load of the bed during a part of the respective loading process.

Disclosure of Invention

The embodiments described herein relate to an automated system for a general purpose roll-in cot that can improve weight management of the cot, improve balance, and/or make loading easier at any cot height, and at the same time, the roll-in cot can be rolled into different types of rescue vehicles, such as ambulances, vans, station wagons, airplanes, and helicopters.

According to one embodiment, a bed may include a support frame, a front leg, a rear leg, a front actuator, a rear actuator, and one or more processors. The support frame can extend between the front end of the bed and the rear end of the bed. The front and rear legs are slidably coupled to the support frame. The front actuator can be coupled to the front leg. The front actuator is capable of sliding the front leg along the support frame to retract and extend the front leg. The rear actuator can be coupled to the rear leg. The rear actuator can slide the rear leg along the support frame to retract and extend the front leg. The one or more processors can be communicatively coupled to the front actuator and the rear actuator. The one or more processors execute machine readable instructions to receive signals from one or more sensors indicative of the front end and front legs of the bed. When the front end of the bed is supported by a surface and the front legs are retracted a predetermined amount, the one or more processors can actuate the rear actuators to extend the rear legs, thereby raising the rear end of the bed.

In some embodiments, the one or more sensors may include a front angle sensor that measures a front angle between the front leg and the support frame. The front angle sensor can communicate a front angle signal to the one or more processors such that the front angle signal is correlated to the front angle. The one or more processors are capable of executing machine readable instructions to determine that the front leg is retracted by a predetermined amount based at least in part on the front angle. Alternatively or additionally, the front angle sensor may be a potentiometer rotation sensor or a hall effect rotation sensor.

According to embodiments described herein, the one or more sensors may include a rear angle sensor that measures a rear angle between the rear leg and the support frame. The back angle sensor is capable of communicating the back angle signal to the one or more processors such that the back angle signal is correlated to the back angle. The rear angle sensor may be a potentiometer rotation sensor or a hall effect rotation sensor. The one or more processors are capable of executing the machine readable instructions to determine a difference between the back angle and the front angle based at least in part on the front angle signal and the back angle signal. Alternatively or additionally, the one or more processors are capable of executing machine readable instructions to compare a difference between the back angle and the front angle to a predetermined angle difference. The rear leg may be automatically extended when a difference between the rear angle and the front angle is greater than or equal to a predetermined angle difference.

The one or more sensors may include a distance sensor that measures a distance indicative of a position of the front leg or the rear leg or both the front leg and the rear leg relative to the support frame. The distance sensor can communicate the distance signal to the one or more processors such that the distance signal is associated with the distance. The one or more sensors may include a distance sensor that measures a distance indicative of a position of the front end of the bed relative to the surface and communicates a distance signal to the one or more processors such that the distance signal is associated with the distance. The distance sensor can be coupled to the support frame or the rear actuator. The distance sensor may be an ultrasonic sensor, a contact sensor or a proximity sensor.

According to embodiments described herein, the bed may comprise a front actuator sensor and a rear actuator sensor. The front actuator sensor can be communicatively coupled to the one or more processors. The front actuator sensor is configured to measure a force applied to the front actuator and to transmit a front actuator force signal that is correlated to the force applied to the front actuator. The rear actuator sensor can be communicatively coupled to the one or more processors. The rear actuator sensor is configured to measure a force applied to the rear actuator and to transmit a rear actuator force signal that is correlated to the force applied to the rear actuator. The one or more processors are capable of executing machine readable instructions to determine that the front actuator force signal is indicative of extension and the rear actuator force signal is indicative of compression. The rear legs can be automatically extended when the front actuator force signal indicates extension and the rear actuator force signal indicates compression.

According to embodiments described herein, if the position of the rear leg relative to the rear end of the cot does not change for a predetermined period of time after the rear actuator is actuated, the one or more processors can execute machine readable instructions to abort actuation of the rear actuator.

In another embodiment, a bed may include a support frame, a front leg, a rear leg, a middle portion, and a line indicator. The support frame can extend between the front end of the bed and the rear end of the bed. The front and rear legs can be slidably coupled to the support frame. The front and rear legs can be retracted and extended to facilitate loading or unloading from a support surface. The intermediate portion may be arranged between the front end of the bed and the rear end of the bed. The line indicator can be coupled to the bed. The line indicator is capable of projecting light indicative of a middle portion of the bed. Alternatively or additionally, the light rays can be projected from below or near the middle portion of the bed to a point offset from the sides of the bed. Alternatively or additionally, the line indicator may comprise a laser, a light emitting diode, or a projector.

According to embodiments described herein, the intermediate load wheel can be coupled to the front leg between the proximal end and the distal end of the front leg. The intermediate load wheel can be generally aligned with the light during loading or unloading. Alternatively or additionally, the intermediate load wheels can act as fulcrums during loading or unloading. Alternatively or additionally, the intermediate load wheels can be located at the centre of balance of the bed during loading or unloading.

According to embodiments described herein, the one or more processors can be communicatively coupled to the line indicator. The one or more processors execute the machine readable instructions to receive signals from one or more sensors representative of the front end of the bed. The one or more processors execute machine readable instructions to cause the line indicator to project light when the front end of the bed is positioned over the support surface.

According to embodiments described herein, the bed may include a rear actuator and a rear actuator sensor. The rear actuator can be coupled to the rear leg. The rear actuator can slide the rear leg along the support frame to retract and extend the front leg. The rear actuator sensor can be communicatively coupled to the one or more processors. The rear actuator sensor is capable of measuring a force applied to the rear actuator and is capable of transmitting a rear actuator force signal associated with the force of the rear brake. The one or more processors are capable of executing the machine readable instructions to determine that the rear actuator force signal is indicative of stretch. When the rear actuator force signal indicates extension, light may be projected.

According to embodiments described herein, the one or more sensors may comprise a distance sensor that measures a distance indicative of the position of the front end of the bed relative to the support surface. The distance sensor can communicate the distance signal to the one or more processors such that the distance signal is associated with the distance. The one or more processors execute machine readable instructions to determine that the front end of the bed is above the support surface when the distance is within a definable range. The distance sensor can be coupled to the rear actuator or aligned with the intermediate load wheel. The distance sensor may be an ultrasonic sensor, a contact sensor or a proximity sensor.

In another embodiment, a bed may include a support frame, a front leg, a rear leg, an actuator, a travel light, one or more processors, and one or more operator controls. The support frame can extend between the front end of the bed and the rear end of the bed. The front and rear legs can be slidably coupled to the support frame. The actuator can be coupled to the front leg or the rear leg. The actuator can slide the front leg or the rear leg along the support frame to actuate the support frame. The travel light can be coupled to the actuator. The one or more processors can be communicatively coupled to the running light. The one or more operator controls can be communicatively coupled to the one or more processors. Upon receiving input from one or more operator controls, the one or more processors can execute machine-readable instructions to automatically indicate the travel light illumination. The actuator can actuate the front leg and the travel light can illuminate an area forward of the front end of the bed. The actuator can actuate the rear leg and the travel light can illuminate an area behind the rear end of the bed.

These and additional features provided by embodiments of the present disclosure will be more fully understood from the following detailed description taken in conjunction with the accompanying drawings.

Drawings

The following detailed description of specific embodiments of the present disclosure can be best understood when read in conjunction with the following drawings, where like structure is indicated with like reference numerals and in which:

fig. 1 is a perspective view illustrating a bed according to one or more embodiments described herein;

fig. 2 is a top view illustrating a bed according to one or more embodiments described herein;

fig. 3 is a side view illustrating a bed according to one or more embodiments described herein;

4A-4C are side views illustrating a raising and/or lowering sequence of a bed according to one or more embodiments described herein;

fig. 5A-5E are side views illustrating a loading and/or unloading sequence of a bed according to one or more embodiments described herein;

fig. 6 schematically illustrates an actuator system of a bed according to one or more embodiments described herein; and

fig. 7 schematically illustrates a bed having an electrical system according to one or more embodiments described herein.

The embodiments depicted in the drawings are illustrative in nature and are not intended to be limiting of the embodiments described herein. Furthermore, various features of the drawings and embodiments will be more fully apparent and understood in view of the detailed description.

Detailed Description

Referring to fig. 1, a roll-in bed 10 for transport and loading is shown. Roll-in bed 10 includes a support frame 12, with support frame 12 including a front end 17 and a rear end 19. As used herein, the front end 17 is synonymous with the loading end, i.e., the end of the roll-in bed 10 that is loaded onto the loading surface first. Conversely, when used herein, the rear end 19 is the end of the roll-in bed 10 that is loaded last onto the loading surface. Additionally, it should be noted that when roll-in cot 10 is loaded with a patient, the patient's head may be closest to front end 17 and the patient's feet may be closest to rear end 19. Thus, the phrase "head end" may be used interchangeably with the phrase "front end", while the phrase "foot end" may be used interchangeably with the phrase "rear end". Further, it should be noted that the phrases "front end" and "back end" may be interchanged. Thus, although consistent terminology is used throughout for clarity, the embodiments described herein may be reversed without departing from the scope of the disclosure. Generally, as used herein, the term "patient" refers to any living object or previously living object, such as a human, an animal, a cadaver, and the like.

Referring collectively to fig. 2 and 3, the front end 17 and/or the rear end 19 may be retractable. In one embodiment, the front end 17 may be extendable and/or retractable (generally indicated by arrow 217 in FIG. 2). In another embodiment, the rear end 19 may be extendable and/or retractable (generally indicated by arrow 219 in FIG. 2). Thus, the overall length between anterior end 17 and posterior end 19 may be increased and/or decreased to accommodate patients of different sizes.

Referring collectively to fig. 1-3, the support frame 12 may include a pair of generally parallel lateral side members 15 extending between a front end 17 and a rear end 19. Various configurations for the lateral side members 15 are conceivable. In one embodiment, the lateral side members 15 may be a pair of spaced apart metal rails. In another embodiment, the lateral side member 15 includes a recessed portion that can be engaged with an auxiliary clip (not shown). These auxiliary clips may be used to removably couple a patient care accessory (e.g., a pole for intravenous drip) to the recessed portion. A recessed portion may be provided along the entire length of the lateral side members to allow for removable clamping of the accessory to a number of different locations on the roll-in bed 10.

Referring again to fig. 1, roll-in bed 10 further includes: a pair of retractable and extendable front legs 20, said front legs 20 being coupled to the support frame 12; and a pair of retractable and extendable rear legs 40, said rear legs 40 being coupled to the support frame 12. Roll-in bed 10 may comprise any rigid material, such as a metal structure or a composite structure. Specifically, the support frame 12, the front leg 20, the rear leg 40, or a combination thereof may include carbon fiber and resin structures. Roll-in bed 10 may be raised to multiple heights by extending front legs 20 and/or rear legs 40, or roll-in bed 10 may be lowered to multiple heights by retracting front legs 20 and/or rear legs 40, as described in more detail herein. It should be noted that as used herein, terms such as "raised," "lowered," "above," "below," and "height" are used to refer to the relationship in distance between objects as measured along a line parallel to gravity using a reference (e.g., the surface supporting the bed).

In particular embodiments, each of the front and rear legs 20, 40 may be coupled to the lateral side members 15. As shown in fig. 4A to 5E, the front leg 20 and the rear leg 40 may cross each other when the bed is viewed from the side, and particularly, the front leg 20 and the rear leg 40 may cross each other at respective positions where the front leg 20 and the rear leg 40 are coupled to the support frame 12, such as the lateral side members 15 (fig. 1 to 3). As shown in the embodiment of fig. 1, the rear leg 40 may be disposed inside the front leg 20, i.e.: the front legs 20 may be spaced a greater distance from each other than the rear legs 40, such that each rear leg 40 is located between the front legs 20. Additionally, the front and rear legs 20, 40 may include front and rear wheels 26, 46, the front and rear wheels 26, 46 enabling the roll-in bed 10 to roll.

In one embodiment, the front wheels 26 and the rear wheels 46 may be swivel casters or swivel lockwheels (swiftl). When raising and/or lowering roll-in bed 10, front wheels 26 and rear wheels 46 may be synchronized to ensure that the plane of lateral side members 15 of roll-in bed 10 and the plane of wheels 26, 46 are generally parallel.

Referring again to fig. 1-3, roll-in cot 10 may further comprise a cot actuation system comprising a front actuator 16 configured to move the front leg 20 and a rear actuator 18 configured to move the rear leg 40. The bed actuation system may include one unit (e.g., a centrally controlled motor and pump) configured to control both the front actuator 16 and the rear actuator 18. For example, the bed actuation system may include a housing having one motor that can drive the front actuator 16, the rear actuator 18, or both, using valves, control logic, or the like. Alternatively, as shown in fig. 1, the cot actuation system may comprise separate units configured to control the front actuator 16 and the rear actuator 18, respectively. In this embodiment, each of the front actuator 16 and the rear actuator 18 may include a separate housing having a separate motor to drive each of the front actuator 16 and the rear actuator 18.

Front actuator 16 is coupled to support frame 12 and is configured to actuate front leg 20 and raise and/or lower front end 17 of roll-in bed 10. Additionally, a rear actuator 18 is coupled to support frame 12 and is configured to actuate rear legs 40 and raise and/or lower rear end 19 of roll-in bed 10. Roll-in bed 10 may be powered by any suitable power source. For example, roll-in bed 10 may include a battery that may provide a power source for the roll-in bed, such as about 24V nominal voltage or about 32V nominal voltage.

The front actuator 16 and the rear actuator 18 can be operated simultaneously or independently to actuate the front leg 20 and the rear leg 40. As shown in fig. 4A-5E, simultaneous and/or independent actuation allows for setting of roll-in bed 10 to different heights. The actuators described herein are capable of providing about 350 pounds (about 158.8kg) of power and about 500 pounds (about 226.8kg) of static force. Further, the front actuator 16 and the rear actuator 18 may be operated by a centralized motor system or a plurality of independent motor systems.

In one embodiment, as schematically shown in fig. 1-3 and 6, front actuator 16 and rear actuator 18 comprise hydraulic actuators for actuating roll-in bed 10. In one embodiment, the front actuator 16 and the rear actuator 18 are dual piggyback hydraulic actuators, i.e., each of the front actuator 16 and the rear actuator 18 form a master-slave hydraulic circuit. The master-slave hydraulic circuit includes four hydraulic cylinders with four extension rods that are piggy-backed (i.e., mechanically linked) to each other in pairs. Thus, a dual piggyback actuator comprises a first hydraulic cylinder having a first rod, a second hydraulic cylinder having a second rod, a third hydraulic cylinder having a third rod, and a fourth hydraulic cylinder having a fourth rod. It should be noted that although the embodiments described herein frequently refer to a master-slave system comprising four hydraulic cylinders, the master-slave hydraulic circuit described herein can comprise any even number of hydraulic cylinders.

Referring to fig. 6, the front actuator 16 and the rear actuator 18 include a rigid support frame 180, the rigid support frame 180 being generally "H" -shaped (i.e., two vertical portions connected by a transverse portion). The rigid support frame 180 includes a cross member 182 that is coupled to the two vertical members 184 at about the middle of each of the two vertical members 184. The pump motor 160 and the reservoir 162 are coupled to and in fluid communication with the cross member 182. In one embodiment, the pump motor 160 and the reservoir 162 are disposed on opposite sides of the cross member 182 (e.g., the reservoir 162 is disposed above the pump motor 160). Specifically, pump motor 160 may be a brushed bi-directional rotary motor having a peak output of approximately 1400 watts. The rigid support frame 180 may include additional cross members or tie plates to provide greater rigidity and prevent the vertical members 184 from twisting or moving laterally relative to the cross members 182 during actuation.

Each vertical member 184 includes a pair of backpack hydraulic cylinders (i.e., a first and second hydraulic cylinder, or a third and fourth hydraulic cylinder), wherein the first hydraulic cylinder extends the rod in a first direction and the second hydraulic cylinder extends the rod in a generally opposite direction. When the hydraulic cylinders are arranged in a master-slave configuration, one of the vertical members 184 includes an upper master cylinder 168 and a lower master cylinder 268. The other of the vertical members 184 includes an upper slave cylinder 169 and a lower slave cylinder 269. It should be noted that although master cylinders 168, 268 are piggybacked together and have levers 165, 265 extending in generally opposite directions, master cylinders 168, 268 may be located in alternating vertical members 184 and/or have levers 165, 265 extending in generally the same direction.

Referring now to fig. 7, control box 50 is communicatively coupled (generally represented by arrowed lines) to one or more processors 100. Each of the one or more processors can be any device that can execute machine-readable instructions, e.g., a controller, an integrated circuit, a microchip, and the like. As used herein, the term "communicatively coupled" means that the components are capable of exchanging data signals with each other, such as exchanging electrical signals via a conductive medium, exchanging electromagnetic signals via air, exchanging optical signals via an optical waveguide, and so forth.

The one or more processors 100 can be communicatively coupled to one or more memory modules 102, which memory modules 102 can be any devices capable of storing machine-readable instructions. The one or more memory modules 102 may include any type of memory, such as: read Only Memory (ROM), Random Access Memory (RAM), secondary storage (e.g., a hard disk drive), or a combination thereof. Suitable examples of ROM include, but are not limited to, programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), electrically erasable read-only memory (EAROM), flash memory, or combinations thereof. Suitable examples of RAM include, but are not limited to, Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM).

The embodiments described herein are capable of performing some methods automatically by executing machine-readable instructions with one or more processors 100. The machine-readable instructions may comprise logic or one or more algorithms written in any programming language of any generation (e.g., 1GL, 2GL, 3GL, 4GL, or 5GL), such as: machine language that can be directly executed by a processor; or assembly language, object-oriented programming (OOP), scripting language, microcode, etc., that may be compiled or assembled into machine-readable instructions and stored. Alternatively, the machine-readable instructions may be written in a Hardware Description Language (HDL) such as logic implemented via any Field Programmable Gate Array (FPGA) configuration or Application Specific Integrated Circuit (ASIC) or their equivalents. Thus, the methods described herein may be implemented in any conventional computer programming language, as preprogrammed hardware elements, or as a combination of hardware and software components.

Referring collectively to fig. 2 and 7, the front actuator sensors 62 and the rear actuator sensors 64 are communicatively coupled to one or more processors 100, the front actuator sensors 62 and the rear actuator sensors 64 configured to detect whether the front and rear actuators 16, 18 are in tension or compression, respectively. As used herein, the term "stretch" means that a pulling force is detected by a sensor. Such pulling forces are typically associated with removing the load from the legs coupled to the actuator, i.e.: the legs and/or wheels are suspended from the support frame 12 without contact with a surface below the support frame 12. Additionally, as used herein, the term "compression" means that the thrust is detected by a sensor. Such thrust forces are typically associated with applying a load to a leg coupled to the actuator, namely: the legs and/or wheels contact a surface below the support frame 12 and transmit the compressive strain to the coupled actuator.

In one embodiment, the front actuator sensor 62 and the rear actuator sensor 64 are coupled to the support frame 12; however, other positions or configurations are also contemplated herein. The sensors may be proximity sensors, strain gauges, load cells, hall effect sensors, or any other suitable sensors that may be used to detect when the front actuator 16 and/or the rear sensor 18 are in tension or compression. In further embodiments, the front actuator sensor 62 and the rear actuator sensor 64 may be used to detect the weight of a patient disposed on the roll-in bed 10 (e.g., when using strain gauges). It should be noted that the term "sensor" as used herein denotes a device that measures a physical quantity and converts it into a signal that is related to the measured value of the physical quantity. Furthermore, the term "signal" denotes an electrical, magnetic or optical waveform that can be transferred from one location to another, for example: current, voltage, flux, DC, AC, sine wave, triangular wave, square wave, etc.

Referring collectively to fig. 3 and 7, roll-in bed 10 can include front angle sensor 66 and rear angle sensor 68, which front angle sensor 66 and rear angle sensor 68 are communicatively coupled to one or more processors 100 front angle sensor 66 and rear angle sensor 68 can be any sensor that measures a true angle or change in angle, such as a potentiometer rotation sensor, a hall effect rotation sensor, or the like_fThe rear angle sensor 68 can be used to detect the rear angle α of the pivotal coupling of the rear leg 40_bIn one embodiment, front angle sensor 66 and rear angle sensor 68 are operably coupled to front leg 20 and rear leg 40, respectively, accordingly, one or more processors 100 are capable of executing machine readable instructions to determine rear angle α_bAnd front angle α_fThe load state angle may be set to an angle such as about 20 deg. or any other angle that generally indicates that the roll-in bed 10 is in the load state (representing loading and/or unloading). accordingly, when the angle difference exceeds the load state angle, the roll-in bed 10 may detect that it is in the load state and perform certain actions depending on being in the load state_fAnd back angle α_bSimilar measurements are made. For example, the angle can be determined by the positioning of the front legs 20 and/or the rear legs 40 relative to the lateral side members 15. For example, can be along a crossThe distance between the front leg 20 and the reference point is measured towards the side member 15. Similarly, the distance between the rear leg 40 and the reference point can be measured along the lateral side member 15. Further, the distance that the front actuator 16 and the rear actuator 18 extend can be measured. Thus, any of the distance measurements or angle measurements described herein can be used interchangeably to determine the positioning of components of roll-in bed 10.

Additionally, it should be noted that a distance sensor may be coupled to any portion of roll-in bed 10 such that the distance between the lower surface and the component (e.g., front end 17, rear end 19, front load wheels 70, front wheels 26, intermediate load wheels 30, rear wheels 46, front actuator 16, or rear actuator 18) may be determined.

Referring collectively to fig. 3 and 7, the front end 17 may include a pair of front load wheels 70, the front load wheels 70 configured to assist in loading the roll-in cot 10 onto a load-bearing surface (e.g., the floor of an ambulance). Roll-in bed 10 may include load end sensors 76 communicatively coupled to one or more processors 100. The load end sensor 76 is a distance sensor for detecting the position of the front load wheel 70 relative to the load bearing surface (e.g., the distance of the detected surface from the front load wheel 70). Suitable distance sensors include, but are not limited to, ultrasonic sensors, contact sensors, proximity sensors, or any other sensor capable of detecting a distance to an object. In one embodiment, the load end sensor 76 may be used to directly or indirectly detect the distance between the front load wheel 70 and a surface located generally directly below the front load wheel 70. Specifically, the load end sensor 76 can provide an indication when the surface is within a definable range of distances from the front load wheel 70, for example, when the surface is greater than a first distance and less than a second distance. Thus, the definable range may be set such that a positive (positive) indication is provided by the load end sensor 76 when the front load wheel 70 of the roll-in bed 10 is in contact with the load surface. It is important to ensure that both front load wheels 70 are on the load surface, especially when the roll-in cot 10 is loaded into an ambulance on a grade.

The front leg 20 may include an intermediate load wheel 30 attached to the front leg 20. In one embodiment, intermediate load wheels 30 may be disposed on front legs 20 adjacent front cross member 22 (fig. 1). Roll-in bed 10 may include an intermediate load sensor 77 communicatively coupled to one or more processors 100. The intermediate load sensor 77 is a distance sensor for detecting the distance between the intermediate load wheel 30 and the load surface 500. In one embodiment, the intermediate load sensor 77 may provide a signal to the one or more processors 100 when the intermediate load wheel 30 is within a set distance from the load bearing surface. Although the figures show the intermediate load wheels 30 only on the front legs 20, it is also contemplated that the intermediate load wheels 30 may also be disposed on the rear legs 40 or at any other location on the roll-in bed 10 such that the intermediate load wheels 30 cooperate with the front load wheels 70 to assist in loading and/or unloading (e.g., the support frame 12). For example, the intermediate load wheels can be disposed at any location that is likely to act as a fulcrum or center of balance during the loading and/or unloading process described herein.

Roll-in bed 10 may include a rear actuator sensor 78 communicatively coupled to one or more processors 100. The rear actuator sensor 78 is a distance sensor for detecting the distance between the rear actuator 18 and the load bearing surface. In one embodiment, when the rear legs 40 are substantially fully retracted (fig. 4, 5D, and 5E), the rear actuator sensor 78 may be used to directly or indirectly detect a distance between the rear actuator 18 and a surface located substantially directly below the rear actuator 18. Specifically, the rear actuator sensor 78 can provide an indication when the surface is within a definable range of distance from the rear actuator 78, for example, when the surface is greater than a first distance and less than a second distance.

Still referring to fig. 3 and 7, roll-in bed 10 may include a forward light 86 communicatively coupled to one or more processors 100. The forward light 86 can be coupled to the front actuator 16 and configured to connect with the front actuator 16. Thus, forward light 86 can illuminate the area directly in front of front end 17 of roll-in bed 10 when roll-in bed 10 is rolled with front actuator 16 in extension, retraction, or any position in between. Roll-in bed 10 may also include a back row light 88 communicatively coupled to one or more processors 100. The rear row of lights 88 can be coupled to the rear actuator 18 and configured to connect with the rear actuator. Thus, the back row light 88 can illuminate an area directly behind the rear end 19 of the roll-in bed 10 when the roll-in bed 10 is rolled with the rear actuator 18 in an extended, retracted, or any position in between. The one or more processors 100 can receive input from any of the operator controls described herein and activate the forward light 16 or the rear light 18 or both the forward light 16 and the rear light 18.

Referring collectively to fig. 1 and 7, roll-in bed 10 may include line indicator 74 communicatively coupled to one or more processors 100. Line indicator 74 may be any light source configured to project a straight line indication onto a surface, such as: lasers, light emitting diodes, projectors, and the like. In one embodiment, line indicator 74 can be coupled to roll-in bed 10 and configured to project a line on a surface under roll-in bed 10 such that the line is aligned with intermediate load wheel 30. The line can travel from a point below roll-in bed 10 or a point adjacent to roll-in bed 10 to a point offset from the side of roll-in bed 10. Thus, an operator at the rear end 19 of the cot can maintain visual contact with the line as the line indicator projects the line, and use the line as a positional reference of the center of balance (e.g., the middle load wheel 30) of the roll-in cot 10 during loading or unloading, or during loading and unloading.

Rear end 19 may include operator controls for roll-in bed 10. As used herein, an operator control comprises: an input component that receives an operator's command; and an output component that provides an indication to an operator. Thus, the operator can use the operating controls during loading and unloading of the roll-in bed 10 by controlling the movement of the front legs 20, the rear legs 40, and the support frame 12. The operator controls may include a control box 50 disposed on the rear end 19 of the roll-in bed 10. For example, the control box 50 may be communicatively coupled to one or more processors 100, which processors 100 may in turn be communicatively coupled to the front and rear actuators 16, 18. The control box 50 may include visual display components 58, such as: liquid crystal displays, touch screens, and the like. Thus, the control box 50 can receive inputs that can be processed by one or the processors 100 to control the front actuator 16 and the rear actuator 18. It should be noted that although the embodiments described herein refer to the automated operation of the front and rear actuators 16, 18, the embodiments described herein can include operator controls configured to directly control the front and rear actuators 16, 18. Namely: the automatic process described herein can be overridden by a user and the front actuator 16 and rear actuator 18 can be actuated independent of sensor input.

The operation controls may include one or more manual controls 57 (e.g., buttons on a telescoping handle), the manual controls 57 being disposed on the rear end 19 of the roll-in bed 10. As an alternative to the manual controller embodiment, control box 50 may also include components that may be used to raise and lower roll-in bed 10. In one embodiment, this component is a toggle switch 52, which toggle switch 52 is capable of raising (+) or lowering (-) the bed. Other buttons, switches, or knobs are also suitable. Since the sensors are integrated into roll-in bed 10, as explained in more detail herein, toggle switch 52 may be used to control either front leg 20 or rear leg 40, which front leg 20 or rear leg 40 may be raised, lowered, retracted, or released depending on the position of roll-in bed 10.

In one embodiment, the toggle switch is analog (i.e., the analog switch pressure and/or displacement is proportional to the actuation speed). The operator controls may include visual display components 58, with the visual display components 58 configured to inform an operator whether the front and rear actuators 16, 18 are activated or deactivated and thus capable of being raised, lowered, retracted, or released. Although in the present embodiment the operator controls are arranged at the rear end 19 of the roll-in bed 10, it is also conceivable that the operator controls could be placed at alternative locations of the support frame 12, for example on the sides or front end 17 of the support frame 12. In further embodiments, the operator controls may be located in removably attached wireless remote control devices that may control roll-in bed 10 without being physically attached to roll-in bed 10.

Turning now to the embodiment of roll-in bed 10 that is actuated simultaneously, the bed of fig. 2 is shown in an extended state, whereby front actuator sensor 62 and rear actuator sensor 64 detect that front actuator 16 and rear actuator 18 are in a compressed state, i.e.: the front leg 20 and the rear leg 40 are in contact with the lower surface and are loaded. When the front and rear actuator sensors 62, 64 detect that the front and rear actuators 16, 18, respectively, are each in a compressed state, the front and rear actuators 16, 18 are each in an activated state, and the operator can use the operator controls to raise or lower the front and rear actuators 16, 18 (e.g., "-" is lowered and "+" is raised).

Referring collectively to fig. 4A-4C, an embodiment of roll-in bed 10 is schematically shown that is raised (fig. 4A-4C) or lowered (fig. 4C-4A) by simultaneous actuation (note: front actuator 16 and rear actuator 18 are not shown in fig. 4A-4C for clarity). In the illustrated embodiment, the roll-in bed 10 includes a support frame 12, the support frame 12 slidably engaging a pair of front legs 20 and a pair of rear legs 40. Each front leg 20 is rotatably coupled to a front hinge member 24, the front hinge member 24 being rotatably coupled to the support frame 12. Each rear leg 40 is rotatably coupled to a rear hinge member 44, the rear hinge member 44 being rotatably coupled to the support frame 12. In the illustrated embodiment, the front hinge member 24 is rotatably coupled near the front end 17 of the support frame 12, and the rear hinge member 44 is rotatably coupled near the rear end 19 to the support frame 12.

Fig. 4A shows roll-in bed 10 in the lowermost transport position. Specifically, the rear wheels 46 and the front wheels 26 are in contact with the surface, the front legs 20 slidingly engage the support frame 12 such that the front legs 20 contact a portion of the support frame 12 near the rear end 19, and the rear legs 40 slidingly engage the support frame 12 such that the rear legs 40 contact a portion of the support frame 12 near the front end 17. Fig. 4B shows roll-in bed 10 in an intermediate transport position, namely: the front and rear legs 20, 40 are in an intermediate shipping position along the support frame 12. Fig. 4C shows roll-in bed 10 in the highest transport position, i.e.: the front and rear legs 20, 40 are placed along the support frame 12 such that the front load wheels 70 are at a maximum desired height that can be set to a height sufficient to load the bed, as described in more detail herein.

The embodiments described herein may be used to lift a patient from a position below the vehicle in preparation for loading the patient into the vehicle (e.g., from the ground above a load-bearing surface of an ambulance). Specifically, roll-in cot 10 may be raised from the lowermost transport position (fig. 4A) to an intermediate transport position (fig. 4B) or the uppermost transport position (fig. 4C) by simultaneously actuating front leg 20 and rear leg 40 and sliding them along support frame 12. When raised, actuation causes the front legs to slide toward the front end 17 and rotate about the front hinge members 24, and causes the rear legs 40 to slide toward the rear end 19 and rotate about the rear hinge members 44. Specifically, the user may interact with control box 50 (fig. 2) and provide an input indication (e.g., by pressing "+" on toggle switch 52) that the roll-in bed 10 needs to be raised. Roll-in bed 10 is raised from its current position (e.g., the lowest transport position or an intermediate transport position) until it reaches the highest transport position. Upon reaching the highest transport position, the actuation may be automatically stopped, namely: to make the roll-in bed 10 rise higher, additional input is required. Input to roll-in bed 10 and/or control box 50 may be provided in any manner (e.g., electronic, acoustic, or manual).

Roll-in bed 10 may be lowered from the intermediate transport position (fig. 4B) or the highest transport position (fig. 4C) to the lowest transport position (fig. 4A) by simultaneously actuating front leg 20 and rear leg 40 and sliding them along support frame 12. Specifically, when lowered, actuation causes the front legs to slide toward the rear end 19 and rotate about the front hinge members 24, and causes the rear legs 40 to slide toward the front end 17 and rotate about the rear hinge members 44. For example, the user may provide an input indication (e.g., by pressing a "-" on toggle switch 52) requesting that roll-in bed 10 be lowered. Upon receiving the input, the roll-in bed 10 is lowered from its current position (e.g., the highest transport position or an intermediate transport position) until it reaches the lowest transport position. Once roll-in bed 10 reaches its lowest height (e.g., lowest transport position), actuation may automatically stop. In some embodiments, control box 50 provides a visual indication that front leg 20 and rear leg 40 are active during movement.

In one embodiment, when roll-in bed 10 is in the highest transport position (fig. 4C), front leg 20 is in contact with support frame 12 at front load-bearing indicia 221, and rear leg 40 is in contact with support frame 12 at rear load-bearing indicia 241. Although the front and rear load-bearing indicia 221, 241 are shown in fig. 4C as being located near the middle of the support frame 12, other embodiments are contemplated in which the front and rear load-bearing indicia 221, 241 are located at any position along the support frame 12. Some embodiments may have a loading position that is higher than the highest shipping position. For example, the top loading position may be set by actuating roll-in bed 10 to a desired height and providing an input indication that requires setting the top loading position (e.g., pressing "+" and "-" on a toggle switch simultaneously for 10 seconds).

In another embodiment, control box 50 provides an indication that roll-in bed 10 has exceeded the maximum transport position and that roll-in bed 10 needs to be lowered at any time after roll-in bed 10 is raised above the maximum transport position for a set period of time (e.g., 30 seconds). The indication may be visual, audible, electronic, or a combination thereof.

When roll-in bed 10 is in the lowermost transport position (fig. 4A), front leg 20 may contact support frame 12 at front flat flag 220, which front flat flag 220 is located near rear end 19 of support frame 12, and rear leg 40 may contact support frame 12 at rear flat flag 240, which rear flat flag 240 is located near front end 17 of support frame 12. Furthermore, it should be noted that, as used herein, the term "sign" denotes a position along the support frame 12, which corresponds to a mechanical or electrical stop, for example: a barrier located within a channel formed in the lateral side member 15; a locking mechanism; or a stop controlled by a servo.

The front actuator 16 may be used to raise or lower the front end 17 of the support frame 12 independently of the rear actuator 18. The rear actuator 18 may be used to raise or lower the rear end 19 of the support frame 12 independently of the front actuator 16. By independently raising the front end 17 or the rear end 19, the roll-in bed 10 is able to maintain the support frame 12 horizontal or substantially horizontal as the roll-in bed 10 moves over an uneven surface (e.g., stairs or a slope). Specifically, if one of front leg 20 or rear leg 40 is in tension, the set of legs that are not in contact with the surface (i.e., the set of legs in tension) are actuated by roll-in bed 10 (e.g., roll-in bed 10 is moved away from the curb). Other embodiments of roll-in bed 10 may operate to automatically remain level. For example, if back end 19 is lower than front end 17, "+" on toggle switch 52 is pressed to raise back end 19 to level before roll-in bed 10 is raised, and "-" on toggle switch 52 is pressed to lower front end 17 to level before roll-in bed 10 is lowered.

Referring collectively to fig. 4C-5E, the embodiments described herein may utilize independent actuation to load a patient into a vehicle (note: the front actuator 16 and the rear actuator 18 are not shown in fig. 4C-5E for clarity). In particular, roll-in bed 10 can be loaded onto load bearing surface 500 according to the following process. First, the roll-in bed 10 may be placed at the highest loading position or at any position where the front load wheels 70 are at a higher elevation than the load surface 500. When loading the roll-in bed 10 onto the load-bearing surface 500, the roll-in bed 10 may be raised via the front and rear actuators 16, 18 to ensure that the front load-bearing wheels 70 are placed above the load-bearing surface 500. In some embodiments, the front actuator 16 and the rear actuator 18 can be actuated simultaneously to keep the roll-in bed level until the height of the roll-in bed is at a predetermined position. Once the predetermined height is reached, the front actuator 16 can raise the front end 17 such that the roll-in bed 10 is angled at its highest loading position. Therefore, the roll-in bed 10 can be loaded in a state where the rear end 19 is lower than the front end 17. Then, roll-in bed 10 may be lowered until front load wheels 70 contact load surface 500 (fig. 5A).

As shown in fig. 5A, the front load wheel 70 is positioned above the load surface 500. In one embodiment, the pair of front legs 20 can be actuated by the front actuator 16 after the load wheel contacts the load surface 500 because the front end 17 is above the load surface 500. As shown in fig. 5A and 5B, the middle portion of the roll-in bed 10 is away from the load bearing surface 500 (i.e., a significant portion of the roll-in bed 10 has not yet been loaded beyond the load bearing edge 502 so that a substantial portion of the weight of the roll-in bed 10 can be cantilevered by the wheels 70, 26, and/or 30). When front load wheel 70 is fully loaded, roll-in bed 10 may be held level with reduced force. Additionally, in this position, the front actuator 16 is in tension and the rear actuator 18 is in compression. Thus, for example, if "-" on the toggle switch 52 is actuated, the front leg 20 is raised (fig. 5B).

In one embodiment, the operation of the front actuator 16 and the rear actuator 18 is dependent on the position of the roll-in bed after the front leg 20 has been raised sufficiently to trigger the load-bearing state. In some embodiments, a visual indication is provided on the visual display component 58 (fig. 2) of the control box 50 when the front leg 20 is raised. The visual indication may be coded with a color (e.g., green for actuated legs and red for unactuated legs). The front actuator 16 may automatically cease operation when the front leg 20 has been fully retracted. Further, it should be noted that during retraction of the front leg 20, the front actuator sensor 62 may detect extension, at which time the front actuator 16 may raise the front leg 20 at a higher rate, e.g., fully retracted within about 2 seconds.

Referring to FIG. 3,5B and 7, after front load wheels 70 have been loaded on load surface 500, rear actuator 18 may be automatically actuated by one or more processors 100 to assist in loading roll-in bed 10 onto load surface 500_fLess than the predetermined angle, one or more processors 100 can automatically actuate rear actuator 18 to extend rear leg 40 and raise rear end 19 of roll-in bed 10 above the original load-bearing height. The predetermined angle may be any angle representative of a load bearing state or percentage of extension, for example, less than about 10% of the extension of the front leg 20 in one embodiment or less than about 5% of the extension of the front leg 20 in another embodiment. In some embodiments, prior to automatically actuating the rear actuator 18 to extend the rear legs 40, the one or more processors 100 can determine whether the load end sensor 76 indicates that the front load wheel 70 is touching the load surface 500.

In further embodiments, one or more processors 100 may be capable of monitoring the clearance angle sensor 68 to verify the clearance angle α_bIs changing with the actuation of the rear actuator 18 to protect the rear actuator 18, the rear angle α_bThe one or more processors 100 can automatically discontinue actuation of the rear actuator 18 when improper operation is indicated, for example, if the rear angle α_bWithout a change within a predetermined period of time (e.g., about 200 milliseconds), the one or more processors 100 can automatically abort actuation of the post-actuator 18.

Referring collectively to fig. 5A-5E, after the front legs 20 have been retracted, the roll-in bed 10 may be pushed forward until the intermediate load wheels 30 have been loaded onto the load surface 500 (fig. 5C). As shown in fig. 5C, the front end 17 and the middle portion of the roll-in bed 10 are located above the load bearing surface 500. As a result, the pair of rear legs 40 can be retracted using the rear actuator 18. In particular, the intermediate load sensor 77 is able to detect when the intermediate portion is located above the bearing surface 500. The rear actuator may be actuated when the intermediate portion is above the load bearing surface 500 during a load bearing state (e.g., the front leg 20 and the rear leg 40 have an angular difference greater than the load bearing state angle). In one embodiment, an indication (e.g., a beeping sound may be provided) may be provided by the control box 50 (fig. 2) when the intermediate load wheel 30 passes sufficiently over the load edge 502 to allow actuation of the rear leg 40.

It should be noted that when any portion of roll-in bed 10 that may act as a fulcrum passes sufficiently beyond load bearing edge 502 so that rear leg 40 may be retracted, the middle portion of roll-in bed 10 is above load bearing surface 500 and the force required to lift rear end 19 is less, for example less than half the weight of roll-in bed 10 (which may be loaded) that needs to be supported at rear end 19. Furthermore, it should be noted that the position of roll-in bed 10 may be detected by sensors located on roll-in bed 10 and/or sensors located on or adjacent to load bearing surface 500. For example, an ambulance may have sensors that detect the positioning of roll-in bed 10 relative to load bearing surface 500 and/or load bearing edge 502 and a communication device for communicating information to roll-in bed 10.

Referring to fig. 5D, after retraction of rear leg 40, roll-in bed 10 may be pushed forward. In one embodiment, during retraction of the rear legs, the rear actuator sensor 64 may detect that the rear legs 40 are unloaded, at which time the rear actuator 18 may raise the rear legs 40 at a higher speed. The rear actuator 18 may automatically cease operation upon full retraction of the rear leg 40. In one embodiment, the indication may be provided by control box 50 (fig. 2) when roll-in bed 10 is sufficiently over load-bearing edge 502 (e.g., fully loaded or loaded such that the rear actuator is over load-bearing edge 502).

Once the cot is loaded onto the load bearing surface (fig. 5E), it may be deactivated by lockingly coupling the front and rear actuators 16, 18 to the ambulance. Both the ambulance and roll-in cot 10 may be equipped with components adapted for coupling, such as male and female connectors. Additionally, the roll-in cot 10 may include a sensor that registers when the cot is fully disposed in an ambulance and sends a signal that causes the actuators 16, 18 to be locked. In another embodiment, roll-in bed 10 may be connected to bed fasteners that latch actuators 16, 18, and roll-in bed 10 is also coupled to an ambulance's power system that charges roll-in bed 10. An example of such an ambulance Charging System on the market is the Integrated Charging System (ICS) manufactured by Ferno-Washington corporation.

Referring collectively to fig. 5A-5E, embodiments described herein may utilize independent actuation as described above for unloading roll-in bed 10 from load bearing surface 500. Specifically, roll-in bed 10 may be unlocked from the fastener and roll-in bed 10 pushed toward load-bearing edge 502 (fig. 5E-5D). When the rear wheels 40 are released from the load bearing surface 500 (fig. 5D), the rear actuator sensors 64 detect that the rear legs 40 are unloaded and allow the rear legs 40 to lower. In some embodiments, the rear leg 40 will be prevented from being lowered, for example, when the sensor detects that the bed is not in the correct position (e.g., the rear wheels 46 are above the load surface 500 or the middle load wheels 30 are away from the load edge 502). In one embodiment, an indication may be provided by the control box 50 (fig. 2) when the rear actuator 18 is actuated (e.g., the intermediate load wheel 30 is located near the load edge 502 and/or the rear actuator sensor 64 detects tension).

Referring collectively to fig. 5D and 7, line indicator 74 can be automatically actuated by one or more processors to project a line on load bearing surface 500 for indicating the center of balance of roll-in cot 10. In one embodiment, the one or more processors 100 are capable of receiving input from the intermediate load sensor 77 indicating that the intermediate load wheel 30 is in contact with the load bearing surface. The one or more processors 100 may also receive input from the rear actuator sensors 64 indicating that the rear actuators 18 are in tension. When the intermediate load wheel 30 is in contact with the load surface and the rear actuator 18 is in tension, the one or more processors can automatically cause the line indicator 74 to project a line. Thus, when the line is projected, a visual indication can be provided to the operator on the carrying surface, which can be used as a reference for loading, unloading or both. Specifically, as the line approaches the load bearing edge 502, the operator may reduce the speed of moving the roll-in bed 10 from the load bearing surface 500, which can provide additional time for lowering the rear legs 40. Such an operation can minimize the time required for the operator to support the weight of roll-in bed 10.

Referring collectively to fig. 5A-5E, when roll-in bed 10 is properly positioned relative to load bearing edge 502, rear legs 40 may be extended (fig. 5C). For example, the rear leg 40 may be extended by pressing a "+" on the toggle switch 52. In one embodiment, a visual indication is provided on the visual display member 58 of the control box 50 when the rear leg 40 is lowered (FIG. 2). For example, a visual indication may be provided when roll-in bed 10 is in a loaded state and rear leg 40 and/or front leg 20 is actuated. Such a visual indication may be a signal that the roll-in bed should not be moved (e.g., pulled, pushed, or rolled) during actuation. When the rear leg 40 contacts the ground (fig. 5C), the rear leg 40 is loaded and the rear actuator sensor 64 deactivates the rear actuator 18.

When the sensor detects that the front leg 20 is clear of the load surface 500 (fig. 5B), the front actuator 16 is actuated. In one embodiment, the indication may be provided by the control box 50 when the intermediate load wheel 30 is at the load edge 502 (fig. 2). The front leg 20 is extended until the front leg 20 contacts the ground (fig. 5A). For example, front leg 20 may be extended by pressing a "+" on toggle switch 52. In one embodiment, a visual indication is provided on the visual display member 58 of the control box 50 (FIG. 2) when the front leg 20 is lowered.

It should now be appreciated that the embodiments described herein may be used to transport patients of different sizes by coupling a support surface (e.g., a patient support surface) to a support frame. For example, a lifting stretcher or incubator may be removably coupled to the support frame. Thus, the embodiments described herein may be used to load and transport patients from infants to obese patients. Also, the embodiments described herein may be loaded and/or unloaded from an ambulance by an operator holding a single button to actuate the independently connected legs (e.g., pressing a "-" on the toggle switch to load a bed onto the ambulance, or pressing a "+" on the toggle switch to unload a bed from the ambulance). Specifically, roll-in bed 10 may receive input signals, for example, from an operator control. The input signal may indicate a first direction or a second direction (down or up). The front and rear pairs of legs may be independently lowered when the signal indicates the first direction or raised when the signal indicates the second direction.

It is further noted that terms such as "preferably," "commonly," and "typically" are not utilized herein to limit the scope of the claimed embodiments or to imply that certain features are critical, essential, or even important to the structure or function of the claimed embodiments. Rather, these terms are merely intended to highlight alternative or additional features that may or may not be utilized in a particular embodiment of the present disclosure.

For the purposes of describing and defining the present invention it is additionally noted that the term "substantially" is utilized herein to represent the inherent degree of uncertainty that may be attributed to a quantitative comparison, value, measurement, or other representation. The term "substantially" is also utilized herein to represent the degree by which a quantitative representation may vary from a stated reference without resulting in a change in the basic function of the subject matter at issue.

It will be apparent that modifications and variations are possible by reference to the specific embodiments without departing from the scope of the disclosure defined in the appended claims. More specifically, although some aspects of the present disclosure are identified herein as preferred or particularly advantageous, it is contemplated that the present disclosure is not necessarily limited to these preferred aspects of any particular embodiment.

Claims (10)

1. A bed, the bed comprising:

a support frame extending between a front end of the bed and a rear end of the bed;

front and rear legs slidably coupled to the support frame, wherein the front and rear legs retract and extend to facilitate loading or unloading from a support surface;

a middle portion disposed between the front end of the bed and the rear end of the bed; and

a line indicator coupled to the cot, wherein the line indicator projects light indicative of the middle portion of the cot;

characterized in that the bed further comprises:

one or more processors communicatively coupled to the line indicator, wherein the one or more processors execute machine-readable instructions to:

receiving signals from one or more sensors indicative of the front end of the bed; and is

Causing the line indicator to project the light when the front end of the cot is positioned over the support surface.

2. The bed of claim 1, further comprising:

an intermediate load wheel coupled to the front leg between the proximal and distal ends of the front leg, wherein the intermediate load wheel is generally aligned with the light during loading or unloading.

3. The cot of claim 2, wherein the intermediate load wheels are fulcrums during loading or unloading.

4. The cot of claim 2, wherein the intermediate load wheels are located at a center of balance of the cot during loading or unloading.

5. The bed of claim 1, further comprising:

a rear actuator coupled to the rear leg, wherein the rear actuator slides the rear leg along the support frame to retract and extend the rear leg; and

a rear actuator sensor communicatively coupled to the one or more processors, wherein the rear actuator sensor measures a force applied to the rear actuator and communicates a rear actuator force signal associated with the force applied to the rear actuator, wherein the one or more processors execute machine readable instructions to determine that the rear actuator force signal indicates tension, and wherein the light is projected when the rear actuator force signal indicates tension.

6. The cot of claim 5, wherein the one or more sensors comprise a distance sensor that measures a distance indicative of a position of the front end of the cot relative to the support surface and communicates a distance signal to the one or more processors such that the distance signal is associated with the distance, and wherein the one or more processors execute machine readable instructions to determine that the front end of the cot is positioned above the support surface when the distance is within a defined range.

7. The cot of claim 6, wherein the distance sensor is coupled to the support frame, the rear actuator, or aligned with the intermediate load wheel.

8. The bed of claim 6, wherein the distance sensor is an ultrasonic sensor, a contact sensor, or a proximity sensor.

9. The cot of claim 1, wherein the light rays are projected from below or near a middle portion of the cot to a point offset from a side of the cot.

10. The cot of claim 1, wherein the line indicator comprises a laser, a light emitting diode, or a projector.