MXPA01002585A - Sub-cart-type guided tractor. - Google Patents

Abstract

Herein is described a sub-cart-type guided tractor comprising a frame provided with an actuation unit or propelling unit including propelling wheels at the lower side of it, the guided tractor is able to travel guided by means of a guide signal sent from a guide element, such as a magnetic tape placed along a travel trajectory over a floor surface and to pull a cart provided with free wheels and charged with goods, with the guided tractor situated under a load carrier platform of the cart. The frame or framework of the guided tractor has a height that allows the guided tractor moves under the cart frame and a structure that does not allows the cart vertical load to act upon the guided tractor. The frame or framework of the guided tractor comprises at least two separate frame components arranged in line with the travel direction of the guided tractor and joined by means of a bolt so that it permits the frame components to take a curvature formation or an upward or downward fold. The frame of the guided tractor is provided with free wheels to travel over the floor surface together with the propelling wheels. The frame components are equipped with a clasp mechanism or fastening mechanism able to be raised and folded, and also it is able to be raised and fasten the cart frame when the guided tractor has reached an appropriate position under the cart frame. It is provided a detector in an appropriate portion for detecting the guide signal sent from the guide element, such as a magnetic tape.

Description

SUB-CARRIER GUIDE TYPE TRACTOR BACKGROUND OF THE INVENTION The present invention concerns a guided sub-truck type automatic tractor comprising a frame or frame with a drive unit or drive unit and drive wheels on the underside, such a guided tractor is constructed in order to travel guided by a guide signal sent from a guide element, such as a magnetic tape laid along a path on a floor surface in a factory or warehouse and to pull a wheelbarrow provided with wheels free and loaded with goods, with the guided tractor located under a load carrying platform of the truck. Conventionally with a sub-truck type guided tractor, a frame or frame similar to an undivided rigid plate is used and the driving wheels are attached to the center of the underside of the frame or frame by means of a suspension mechanism using a plate spring, a spring helical or the like. The suspension mechanism prevents the drive wheels from losing contact with the floor surface (the travel path surface) due to irregularities in the surface, ensures proper surface friction and thus allows the guided sub-truck type tractor to travel gently.

REF. DO NOT. 128080 However, the suspension mechanism using such a plate spring, a coil spring or the like can not deal with relatively large irregularities in the surface, such as slopes, waves or the like, although it can deal with small protuberances in the floor surface. Thus, the conventional sub-truck type guided tractor has a problem, when for example the guided tractor passes over a convex portion of the floor surface, the surface friction increases and when it passes over a concave portion of the floor surface, the Surface friction decreases, so proper surface friction is not ensured. When these irregularities of the surface of the floor are relatively large, such as slopes, waves or the like, the truck and the tractor can be tilted at different angles, in such a way that the bottom of the truck comes into contact with the top of the tractor, which prevents the trip. In addition, in the conventional sub-truck type guided tractor, a frame or frame similar to a non-divided rigid plate is generally used. Therefore, when the floor surface has large irregularities, there is for example a risk that when the tractor moves from a downward slope to an upward slope, the driving wheels are lifted off the floor surface, so that the tractor is It becomes uncontrollable. On the other hand, when the tractor moves from an upward slope to a downward slope, there is a risk that the distance between the detector, which is usually placed on a front portion of the tractor as seen from the perspective of the direction of travel of the tractor and guide element, such as a magnetic tape, increases to the extent that the tractor becomes uncontrollable. Thus, the object of the present invention is to provide a sub-truck type guided tractor having a frame capable of being bent, supported by a fulcrum, which can therefore travel uniformly even on a floor surface having large irregularities, such as slopes, waves or the like, without using a special suspension mechanism for the driving wheels or freewheels able to travel on the surface of the floor together with the driving wheels and that can pull a truck safely without the vertical load of the wheelbarrow that acts on the tractor.

BRIEF DESCRIPTION OF THE INVENTION A sub-truck-type guided tractor according to the present invention consists of a frame or frame provided with a drive unit or drive unit including drive wheels on the underside, able to travel guided by a guide signal sent from a guide element such as a magnetic tape lying along a travel path on a floor surface and pulling a wheelbarrow provided with free wheels and loaded with goods, with the guided tractor located under a load carrying platform of the truck. The frame or frame of the guided tractor has a height that allows the guided tractor to move under a truck frame and a structure that does not allow the vertical load of the truck to act on the guided tractor. The guided tractor frame comprises at least two separate frame components that are arranged in line with the travel direction of the guided tractor and are bolted together in such a way that the frame components are allowed to bend in an ascending or falling. The guided tractor frame is provided with free wheels that are able to travel on the surface of the floor together with the driving wheels. The components of the frame are equipped with a clamping mechanism capable of being raised and lowered and the clamping mechanism is able to lift and hold the truck frame when the guided tractor has reached an appropriate position under the truck frame. A detector is provided at an appropriate portion for detecting the guidance signal sent from the guide element such as a magnetic tape.

In the sub-truck guided tractor according to the present invention, the guided tractor frame may comprise two separate front and rear frame components. Each of the frame or frame components is provided with free wheels on left and right sides and the free wheels are able to travel on the surface of the floor together with the driving wheels. The drive unit is located near the portion of the guided tractor that is capable of forming a curvature in the frame. Detectors of a front center portion are provided on the front frame component and a rear center portion of the rear frame component. In the sub-truck-type guided tractor according to the present invention, the guided tractor frame may also comprise three separate front, middle and rear frame components. Each of the front and rear frame components is provided with free wheels on the left and right side and the free wheels are suitable for traveling on the surface of the floor together with the driving wheels. The middle frame component is equipped with a clamping mechanism. Addressing drive units are provided as the drive units in the front and rear frame components and detectors are provided in the front and rear of each of the driving drive units.

The free wheels provided in the frame of the guided tractor and the truck can be spring wheels. The sub-truck type guided tractor described above according to the present invention can travel smoothly not only on a horizontal floor surface, but also on a floor surface having large irregularities, such as slopes, waves or the like, even without use a special suspension mechanism for the driving wheels or the free wheels able to travel together with the driving wheels and you can pull a truck securely without the vertical load of the truck acting on the guided tractor.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a front view of a type of a sub-truck-type guided tractor according to the present invention; Figure 2 is a plan view of the embodiment shown in Figure 1; Figures 3A and 3B are front views to show how the modality of Figures 1 and 2 travels; Figure 4 is a front view of a further embodiment of the sub-truck type guided tractor according to the present invention; Figure 5 is a plan view of the embodiment shown in Figure 4; Figure 6 is a front view to show how the mode shown in Figures 4 and 5 travels; Figure 7 is a front view to show how the mode shown in Figures 4 and 5 travels; and Figure 8 is a front view of a further embodiment of the sub-truck type guided tractor according to the present invention.

EXAMPLES OF MODALITIES OF THE INVENTION Figures 1 and 2 show a type of sub-truck-type guided tractor according to the present invention. The guided sub-truck type tractor comprises a frame 1 provided with a driving unit 3 including driving wheels 2 on its lower side. It is apt to travel guided by a guide signal sent from a guide element, such as a magnetic tape 14 stretched along a path of travel on a floor surface 4 and to pull a cart 5 provided with free wheels 11 and loaded with goods, with the guided tractor located under the load carrying platform of the truck 5. The guided tractor type sub-truck has the following characteristics: The frame 1 has a height that allows the guided tractor to move under a frame 6 of the truck 5 and a structure that does not allow the vertical load of the truck 5 to act on the guided tractor. The frame 1 comprises at least two separate frame components 7, 8 which are arranged in line in the travel direction of the guided tractor and joined by a bolt 9, in such a way that the components of the frame 7, 8 are allowed to take a formation bent up or down; The frame 1 is provided with free wheels 12 which are able to travel on the surface 4 of the floor together with the driving wheels 2; The components 7, 8 of the frame are equipped with a clamping mechanism or clamping mechanism 10 capable of being raised and lowered and the clamping mechanism is able to lift and hold the frame 6 of the truck 5 when the guided tractor has reached an appropriate position under the truck frame 5 and a detector 13 provided at an appropriate portion for detecting the guide signal sent from the guide element, such as the magnetic tape 14 (invention cited in claim 1). Specifically, the sub-truck type guided tractor shown in Figures 1 and 2 is a tractor capable of traveling forward and backward. It is a tractor called "double fold type", where the frame 1 comprises two separate front and rear frame components 7, 8. Each of the components 7, 8 of the frame is provided with the free wheels (universal wheels) 12 on the left and right side, more specifically, four free wheels 12 in total, one in each of the four corners of the frame. The freewheels are the types that are easy to direct and suitable for traveling on the surface of the floor together with the driving wheels 2. The driving unit 3 is located near the portion of the frame 1 which is capable of bending. The detectors 13 are provided in a front center portion of the front frame component 7 and a rear center portion of the rear frame component 8 (invention cited in claim 2). More specifically, the driving unit 3 comprises the driving wheels 2 and a motor (not shown) for driving the driving wheels 2 and uses an external frame member of the rear frame component 8, such that the driving unit 3 occupies the side left and right of the center of gravity of frame 1 (center of figure 2) as seen in a plane. The driving unit 3 consists of the driving wheels 2 and the engine carries out the steering using the so-called "two-wheel speed difference method".

The components 7 and 8 of the frame are made of steel and have substantially the same size. The components 7 and 8 of the frame are joined in such a way that they can occupy the front and rear of the center of gravity of the frame 1 (center of figure 2), respectively, as seen in a plane. Here, the driving wheels 2, 2 are provided on both sides of the lower side of the front portion of the outer frame member of the rear frame component 8. On the driving wheels 2, 2 bearings 50, 50 are provided at a lower level than the upper surface of the frame 1. Furthermore plate-like bearings 40, 40 are provided in a rear portion of an external frame member of the component 7 of front frame, in such a way that they extend parallel to the internal sides of the bearings 50, 50. The front frame component 7 and the rear frame component 8 are joined by the shaft 9 of the bolt, in such a way that it is allowed that take an ascending or descending formation. The axial direction of the pin shaft 9 is parallel to the travel surface and perpendicular to the travel direction of the frame. Of course, it can be arranged in such a way that the bearings 40, 40 can be provided in an extension of the external frame member of the front frame component 7, corresponding to the bearings 50, 50 provided in the rear frame component 8. The clamping mechanism or clamp mechanism 10 is provided substantially in the center of the frame 1 to extend over both of the frame components 7, 8. The clamp mechanism 10 is controlled to be raised and lowered by a control device 16 which it includes an electro-hydraulic cylinder that is provided in the center of the frame 1 to extend substantially horizontally (hereinafter referred to herein simply as "cylinder"). The clamping mechanism 10 has four clamps 18, that is, two clamps 18 arranged on the left to face each other and two clamps 18 arranged on the right to face each other. Each clamp 18 is apt to be lifted from the outward positions to the inward position. The clamps 18 have sufficient rigidity to pull the truck 5. In order to ensure that the surface friction required to gently pull the truck 5 to act on the driving wheels 2, the illustrated guided tractor has four iron weights 17 which are arranged in the front and rear of each driving wheel 2. Specifically, the iron weights 17 are arranged on the left and right side of the rear portion of the front frame component 7 in a well balanced manner and on the left and right of the front portion of the rear frame component 8 in a well-balanced manner. The means for ensuring that the required surface friction acts on the driving wheels 2 is not restricted to the previous ones. The weights 17 are not required if they are arranged in such a way that the front frame component 7 has its center of gravity at its rear portion and the rear frame component 8 has its center of gravity at its front portion. In the present embodiment, the magnetic tape 14 is used as the guiding element. However, the guide element is not restricted to the magnetic tape 14. An electrical wire, a magnetic element or an optical guide tape can be used in a similar manner. In Figure 2, the reference number 15 denotes a power supply battery and the reference number 19 denotes a protrusion having a function of obstacle detecting switch for stopping the guided tractor when the guided tractor is brought into contact with a tractor. obstacle. Next, it describes the operation of the sub-truck type guided tractor that has the structural works described above. The programming elements or program (software) for the control device are established in such a way that the sub-truck type guided tractor having the structure described above begins to work with a starting signal of a guest controller using a photoelectric detector or radio transmission and then continues to work automatically in a manner described above until it detects the magnetic tape or the like lying along the travel path indicating a holding position. However, can be arranged in such a way that the guided tractor is started or stopped by an operator that puts a button into operation. The control device is usually placed on the portion of the tractor where the control device does not hide the tractor in its traction work. Since the control device is not particularly new, it is not shown in the drawings. When the sub-truck-type guided tractor is to travel forward in the "X" direction in the drawings, it moves as follows: the detector 13 provided in the front center portion of the front frame component 7 detects the intensity and direction of magnetism of the magnetic tape 14 lying along the travel path on the floor surface. The guided tractor travels automatically when magnetically guided, in such a way that the driving wheels 2, 2 are steered by the automatically controlled driving motor in such a way that the left (or right end) end of the magnetic tape 14 can be detected by the detector 13 in a fixed position. When the guided tractor has reached underneath the truck 5, a detector or the like attached to the frame 7 detects a pulling position 5 of the truck (holding position) and the guided tractor brakes and stops. Then, the cylinder 16 of the clamp mechanism 10 expands, such that the clamps 18, 18 are raised and brought into contact with the frame elements 6, 6 of the truck 5 and hold it. Then, the detector 13 detects the magnetic tape 14 and under the control of the programming elements, the tractor travels by driving the frame 6 of the truck 5 to the left. Thus, the cart 5 is pulled in the "X" direction in the drawings. When the tractor reaches a predetermined position, the detector detects magnetic tape 14 or the like indicating a retention position on the travel path. With this, the cylinder 16 of the clamp mechanism 10 works to release the clamps 18, 18 from the frame elements of the truck 5. The tractor moves under the truck 5 forwards or backwards and waits for the next task. When the sub-truck-type guided tractor travels on a surface 4 of the horizontal floor, the sub-truck-type guided tractor can travel smoothly automatically on the surface 4 of the floor with the drive wheels 2 of the tractor and with the free wheels 12 of the tractor. tractor and the free wheels 11 of the truck 5 which are suitable for traveling with the driving wheels 2, driving the frame 6 of the truck 5 with the clamps 18 of the clamping mechanism 10. When the tractor travels over large irregularities in the surface or for example, it advances from an upward slope to a downward slope, the frame 1 comprising the frame components joined by the bolt shaft 9 is bent upwardly as shown in Figure 3A, in such a way that the freewheels 12 are prevented. of the front frame component 7 are lifted off the floor surface 4. Accordingly, the distance between the detector 13 provided on the front portion of the 1 and the magnetic tape 14 is always kept constant and there is no risk of the tractor becoming uncontrollable. Thus, the tractor can travel as smoothly as when traveling on a horizontal floor surface. On the other hand, when the tractor advances from a downward slope to a downward slope, the frame 1 comprising the frame components joined by the pin shaft 9 is bent downwards as shown in Figure 3B, in such a way that it prevents the driving wheels 2 from being lifted off the floor surface 4. Since the driving wheels 2 always travel in contact with the floor surface, the surface friction required to pull the truck 5 evenly is always present. Thus, there is no risk that the tractor could become uncontrollable if the tractor can travel as uniformly as when traveling on a horizontal floor surface. When the sub-truck type guided tractor is going to travel backwards, it can travel automatically in a similar way to the way described above. Specifically, the detector 13 provided in the rear center portion of the rear frame component 8 detects the intensity and direction of the magnetism of the magnetic tape 14. The guided tractor automatically travels to be magnetically guided in such a way that the driving wheels 2, 2 are addressed by the automatically controlled driving motor in such a way that the left (or right end) end of the magnetic tape 14 can be detected by the detector 13 in a fixed position. When the guided tractor has reached under the truck 5, a detector or the like attached to the frame 1 detects the pulling position of the truck 5 (holding position) and the guided tractor brakes and stops. Then, the cylinder 16 of the clamp mechanism 10 expands, such that the clamps 18, 18 are raised and brought into contact with the frame elements 6, 6 of the truck 5 and hold them. Then, the detector 13 detects the magnetic tape 14 and the tractor travels by driving the frame 6 to the right. Thus, truck 5 is pulled to the right 5. The sub-truck-type guided tractor traveling backwards can not only travel uniformly on a horizontal floor surface. It can also travel uniformly over large irregularities on the surface or from an ascending slope to a descending slope and from a descending slope to an ascending slope. Because the frame 1 comprising the frame components attached by the bolt shaft 9 is bent up (or down) as shown in Figures 3A and 3D, the tractor can travel over large irregularities in the surface so evenly as when traveling on a horizontal floor surface. If spring wheels are used for the freewheels 12 of the frame 1 and the freewheels 11 of the truck 5 (invention described in claim 4), the frame 1 and the truck 5 can travel sufficiently well on a floor surface 4 with waves. Figures 4 and 5 show another embodiment of the sub-truck-type guided tractor according to the invention claimed in claim 1. The guided sub-truck tractor shown is a tractor called "triple-fold type" where a frame 31 comprises 3 separate frame components, that is, front, middle and rear frame components 20, 21, 22. Each of the front and rear frame components 20 and 22 is provided with free wheels 24 on the left and right of its rear portion Thus, four free wheels 12 in total are provided. The freewheels are the types that are easy to steer and suitable for traveling with the driving wheels 23. A clamping mechanism or clamping mechanism 10 is provided in the middle frame component 21. As the driving units, two steering driving units 25 are provided in the front and rear frame components 20 and 22. The detectors 26, 26 are provided in front of and at the rear of each of the driving driving units 25, 25. (invention cited in claim 3). The reference number 27 denotes addressing engines that can rotate forward and backward to allow the associated addressing drive units 25, 25 to perform an addressing function. The addressing drive unit 25 provided with the detector 26 and the addressing motor 27 is similar to the magnetically guided addressing drive unit for use in a magnetically guided truck that was proposed by the inventor (s) present (s) and described in Japanese Unexamined Patent Publication Hei 10-39925. Accordingly, the explanation of the steering drive unit 25 is omitted. The components 20, 21, 22 of the frame are made of steel. The attached portions of the components of the frame have a structure similar to that of the preceding embodiment and the components of the frame are joined by bolt shafts 28. The axes of the bolt shafts 28 extend parallel to the travel surface and perpendicular to the travel direction of the frame. The components of the frame 20, 21 and 22 are joined in a way that the components of the frame can take a formation bent only upwards or downwards. The clamping mechanism 10 is the same as the clamping mechanism 10 shown in figures 1 and 2. Therefore, the explanation thereof is omitted. In order to ensure that the surface friction required to gently pull the truck 5 to act on the driving wheels 23, the illustrated guided tractor has iron weights (not shown) which are arranged in the front and rear frame components 20, 22 of a well balanced way. Also in the present embodiment, a magnetic tape 14 is used as the guiding element. However, the guide element is not restricted to the magnetic tape 14. An electrical wire, a magnetic element or an optical guide tape can be used in a similar manner. In FIGS. 4 and 5, the reference number 30 denotes a protrusion which has an obstacle detection switching function as mentioned in the preceding embodiment. The three-fold sub-trolley guided tractor works in substantially the same way as the double-fold sub-trolley-type guided tractor shown in Figures 1 and 2. Specifically, the programming elements (program or software) for a device control 29 are provided in such a way that the triple-fold sub-trolley-guided tractor starts by working with a start signal for a host controller using a photoelectric detector or radio transmission and then continues to work automatically in a manner that is described later in FIG. present until it detects a magnetic tape or the like stretched along the travel path indicating a holding position. When the triple-fold sub-trolley guided tractor is to travel forward in the "X" direction in the drawings, it moves as follows: The front detectors 26, 26 arranged in front of the driving drive units 25, 25 provided in the front and rear frame components 20, 22 detect the intensity and direction of magnetism of the magnetic tape 14 stretched along the travel path on the floor surface 4. The guided tractor automatically travels when guided in a magnetic manner, so that the steering driving units 25, 25 are addressed by the automatically controlled steering motor 27, 27, such that the left (or right) end of the tractor the magnetic tape 14 can be detected by the detectors 26, 26 in a fixed position. When the guided tractor has reached under the truck 5, a detector or the like detects the pulling position of the truck 5 (holding position) and the guided tractor brakes and stops. Then, the cylinder 16 of the clamping mechanism 10 expands, in such a way that the clamps 18, 18 are raised and come into contact with the frame elements 6, 6 of the truck 5 and hold them. Then, the detectors 26, 26 detect the magnetic tape 14 and the tractor travels by pushing the frame 6 of the truck 5 to the left. Thus, the cart 5 is pulled in the X direction of the drawings. The tractor moves until the detectors detect the magnetic tape 14 or the like indicating a holding position in the travel path. With this, the cylinder 16 of the clamping mechanism 10 works to release the clamps 18, 18 from the frame elements of the truck 5. The tractor moves under the truck 5 to opposite side to the control device 29 and waits the next homework. When the triple-fold sub-trolley guided tractor travels on a horizontal floor surface 4, the triple-fold sub-trolley guided tractor can automatically travel evenly on the floor surface with the driving wheels 23, 23 of the tractor and with the tractor's freewheels 12 and the freewheels 11 of the truck 5 that are able to travel with the driving wheels 23, 23 pushing the frame 6 of the truck 5 with the clamps 18 of the clamping mechanism 10 When the tractor travels over large irregularities in the surface, for example, proceeding from an upward slope to a downward slope, the frame 31 comprising the frame components joined by the bolt shafts 28 is bent upwards as shown in FIG. Figure 6, in such a way that the driving wheels 23, 23 of the front and rear frame components 20, 22 are prevented from being lifted off the floor surface 4. Accordingly, the distance between the front sensors 26, 26 provided in front of the steering driving units 25, 25 and the magnetic tape 14 is always kept constant and there is no risk of the tractor becoming uncontrollable. Thus, the tractor travels as smoothly as when traveling on a horizontal floor surface. On the other hand, when the tractor proceeds from a downward slope to an upward slope, the frame 31 comprising the frame components joined by the axle shafts 28 is bent downwards as shown in Figure 7, in such a way that the driving wheels 23, 23 are prevented from being lifted off the floor surface 4. Since the driving wheels 23, 23 always travel in contact with the floor surface, the surface friction required to pull the truck 5 gently is always present. Thus, there is no risk of the tractor becoming uncontrollable and the tractor traveling as smoothly as when traveling on a horizontal surface. When the sub-truck type guided tractor will travel backward, it can also travel automatically, in substantially the same manner as described above. Therefore, the explanation thereof is omitted. As in the case of the double-fold sub-trolley guided tractor described above, if spring wheels are used for the free wheels 24 of the frame 31 and the free wheels 11 of the truck 5 (invention cited in claim 4), the frame 1 and the truck 5 are able to travel sufficiently well on a floor surface 4 having waves.

The embodiments have been described based on the drawings. It will be noted that the present invention is not restricted to the embodiments shown in the drawings. The present invention encompasses variations that a person skilled in the art would ordinarily produce when modifying and / or making use of the above modalities without deviating from its technical essence. For example, as shown in Fig. 8, steering driving units 25, 25 as shown in Figs. 4 to 7 can be provided in the front and rear frame components 7, 8 of the guided tractor type sub-truck of double fold as shown in Figures 1 to 3. Furthermore, the clamping mechanism or clamp mechanism 10 is not restricted to the structure capable of holding the truck on both sides. As shown in Figure 8, the clamping mechanism or clamping mechanism 33, which has a clamp 32 on only one side can be used, as long as the structure of a tractor remains the same. The clamp 32 is released from the traction work in a similar manner. The explanation of the same will be omitted. In addition, the illustrated embodiments are of the double-fold type and the triple-fold type, but the present invention is not restricted thereto. Of course, the present invention can be implemented, for example, as a type of quadruple fold or quintuple fold.

It is noted that, in relation to this date, the best method known by the applicant to carry out the aforementioned invention, is the conventional one for the manufacture of the objects to which it refers. • •

Claims (4)

1. CLAIMS Having described the invention as above, it is claimed as property, contained in the following claims: 1. A sub-truck-type guided tractor, comprising a frame provided with a drive unit including drive wheels on a lower side thereof , the guided tractor is able to travel guided by a guide signal sent from a guide element, such as a magnetic tape stretched along a travel path on a floor surface and to pull a wheelbarrow provided with free wheels and loaded with goods, in such a state that the guided tractor is placed under a load carrying platform of the truck, characterized in that: the guided tractor frame has a height that allows the guided tractor to move under a frame of the truck and a structure that does not allow a vertical load of the truck to act on the guided tractor, the frame of the tractor gui The invention comprises at least two separate frame components that are arranged in line in a travel direction of the guided tractor and are bolted together in such a manner that the frame components are allowed to take a bending or curving formation upwards or downwards. below, the guided tractor frame is provided with free wheels that are suitable for traveling on the surface of the floor together with the driving wheels, the frame components are equipped with a clamp mechanism or clamping mechanism capable of being lifted and lowered, the clamp mechanism is able to be lifted and to hold the truck frame when the guided tractor has reached a position below the truck frame and a detector is provided at an appropriate portion to detect the guide signal sent from the element of guidance, such as a magnetic tape.
2. 2. The sub-truck guided tractor according to claim 1, characterized in that: the guided tractor frame comprises two separate front and rear frame components, each of the components of the frame is provided with free wheels on a left side and right side thereof, the freewheels are apt to travel on the floor surface together with the driving wheels, the driving unit or driving unit is located near a portion that forms a bend or bend of the curvature formation or folding of the guided tractor frame and detectors are provided in a front center portion of the front frame component and in a rear center portion of the rear frame component.
3. 3. The sub-truck guided tractor according to claim 1, characterized in that: the guided tractor frame comprises three separate front, middle and rear frame components, each of the front and rear frame components are provided with wheels Free wheels on one left side and one right side thereof, the free wheels are suitable for traveling on the floor surface together with the driving wheels, the middle frame component is equipped with a clamping mechanism or clamping mechanism, are provided drive driving units as drive units in the front and rear frame components and detectors are provided in the front and the back of each of the driving drive units.
4. 4. The guided sub-truck-type tractor according to any of claims 1 to 3, characterized in that the free wheels provided in the frame of the guided tractor and the truck consist of spring wheels. SUMMARY OF THE INVENTION A sub-truck-type guided tractor is described which comprises a frame or frame provided with a drive unit or drive unit including drive wheels on the underside thereof, the guided tractor is able to travel guided by a signal of guidance sent from a guidance element, such as a magnetic tape stretched along a travel path on a floor surface and to pull a wheelbarrow provided with free wheels and loaded with goods, with the guided tractor located under a load carrying platform of the truck. The frame or frame of the guided tractor has a height that allows the guided tractor to move under the truck frame and a structure that does not allow the vertical load of the truck to act on the guided tractor. The frame or frame of the guided tractor comprises at least two separate frame components that are arranged in line with the travel direction of the guided tractor and are bolted together in such a way that the frame components are allowed to take a curvature formation or fold up or down. The guided tractor frame is provided with free wheels that are able to travel on the surface of the floor together with the driving wheels. The components of the frame are equipped with a clamping mechanism or clamping mechanism suitable to be ° \ / 2-S S5 lifted and lowered, the clamping mechanism or clamping mechanism is able to be lifted and hold the truck frame when the guided tractor has reached an appropriate position under the truck chassis. A detector is provided at an appropriate portion for detecting the guidance signal sent from the guide element, such as a magnetic tape. or i -ss e