CA1154796A - Devices for automotive vehicle coil springs - Google Patents

Abstract

DEVICES FOR AUTOMOTIVE VEHICLE COIL SPRINGS

Abstract of the Disclosure Devices for progressively stiffening automotive vehicle coil springs comprise spacers positionable between one or more adjacent convolutions of the springs.
The spacers offer no or very minimal resistance to limited compressions of the springs, but an increased resistance to increased compression. The spacers do not interfere with the standard manufactured height of the springs or vehicle, and under normal driving conditions the vehicle rides smoothly on its suspension. However, under severe conditions, which cause sufficient compressions of the springs, the spacers stiffen the vehicle suspension for increased roadability, handling and safety.

Description

~5~96 Background of the Invention _ The present invention relates to improv~ments in automotive vehicle suspension systems, and in particular to spacers insertable between adjacent convolutions of coil springs of a vehicle suspension system, which enable the vehicle to ride smoothly in a designed manner on its suspension under normal driving conditions, but which progressively stiffen the springs and susp.ension system under severe driving conditions.
Conventional automobiles have coil springs at either the front two or all four wheels, which support the vehicle body and frame. The springs isolate the body and frame from roadway shocks and undulations encountered by the wheels, whereby occupants of the vehicle may ride in comfort, and shock absorbers damp oscillations of the body and frame on the springs.
Ordinarily, the coil springs have a stiffness or compressibility which is a compromise between a smooth ride and good vehicle handling. Soft springs provide a cushioned ride and afford maximum passenger comfort on smooth-or slightly undulating roadways. However, springs which are too soft do not offer sufficien~
resistance to acceleration squat ~r braking dive, or to collapse and possibly bottoming under heavy vehicle loads or in response to pronounced roadway undulations or sharp turns at increased speeds, with the result that the vehicle body excessively dips and leans and vehicle handling, roadability and safety are decreased.
Stiff springs, on the other hand, maintain the vehicle body and frame relatively steady and level or horizontal for increased load carrying capability, roadability and handling under severe conditions, but do not satisfactorily isolate the body from roadwa~ shocks and und~llations,

-2-~ 96 so that even on relatively smooth roads a rough ride may be experienced by passengers. Unless a special suspension system is installed, conv?ntional automobiles usually come equipped with springs which compxomise toward a soft ride. Consequently, the suspension system of the average automobile is satisfactory under relatively smooth driving conditions as are usually encountered the majority of the time, but is unsatisfactory, and may actually be dangerous~ under severe roadway or handling conditions or when the vehicle is heavily loaded.
Previous efforts to improve the suspension systems of softly sprung automobiles have heretofore proven generally unsatisfactory. In a first instance, most are quite expensive and difficult to implement, and in a second, they usually provide impxoved roadability and handling only at the expense o~ passenger comfort.
One obvious way to modify a vehicle's suspension system for improved handling and load carrying capability is to replace the original coil springs with heavy duty or relatively stif springs. Unfortunatley, spring replacement is expensive, and results in an uncomfortably hard ride under average driving conditions when the vehicle is not heavily-loaded. A somewhat less expensive approach, although by no means inexpensive, is to replace the vehicle's original shock absorbers with load leveler shock absorbers of the type including separate coil springs for augmenting the vehicle springs. This latter technique, however, usually raises the vehicle body and frame, and also results in a rough or hard ride under average driving conditions. In another instance, air pressurized shock absorbers may be installed on the ~S4~

vehicle. However, the pressure of the air must be continuously accommodated to changing vehicle loading and roadway conditions to maintain satisfactor~
vehicle handling.
Perhaps the least expensive approach heretofore contemplated to stiffen a vehicle's suspension system is the insertion of rigid or metal spacers between adjacent convolutions of the coil springs.
The spacers at all times engage and usually expand the adjacent convolutions, and absolutely prevent any movement of the same together during compression of the remainder of the spring. Although the technique is often favored because of its economy of implementation, the resulting ridability of the vehicle under average driving conditions is harsh.
Objects of the Invention An object of the present invention is to provide an improved and economical means for enhancing the suspension system of an automotive vehicle for improved handling, roadability and load carrying capahility, without sacrifice to passenger riding comfort.
Another object is to provide spacer devices for insertion between one or more adjacent convolutions of the coil springs of an automotive v~hicle's suspension system, which do not interfere with limited compressions o~ the spring~ under normal driving conditions, but offer resistance to increased compressions of the springs under severe conditions.
Summary of the Invention In accordance with the p~esent invention, devices are provided for insertion between one or more adjacent convolutions of the coil springs of automotive vehicle ~s~

suspension systems. In one embodimentl the device comprises a body positionable between adjacent convolutions of a spring, and the body has a length between the convolutions which is less than the spacing therebetween for limited compressions of the spring, but greater than the spacing that would otherwise exist for increased compreSsionC;. Consequently, the bo~y does not impede movement together of the adjacent convolutions for limited compresC;ions of the spring, but upon increased compressions engages the adjacent convolutions and resists further movement together of the same, thereby to stiffen 1he spring against further compression. In this mannex, the device does not interfere with the standard manufacture height o~ the springs and vehicle, occupants of the vehicle are afforded a smooth and comfortable ride under normal drivlng conditions, and yet the vehicle suspension system is stiffened under severe driving conditions for improved handling and safety.
The body may be o~ a rigid material, such as metal or plastic, or of a resilient material, such for example as rubber. An advantage to a resilient material body is that the compliance of the body allows the same to act as a transitional contact member, while at the same time providing noise isolation upon simultaneous contact with the adjacent convolutions.
In another embodiment in which the body is of resilient material, it is configured to normally engage both of the adjacent convolutions, but to impede movement together of the same:only upon sufficient compressions of the spring. In this case, the body ~5~9~

has at least one passage formed generally centrally therethrough, and the passage ha~ walls which collapse to enable the body to readil~ compress in response to movement together of the adjacent convolutions upon limited compressions of the spring. However, the size of the passage is such that opposite side walls of the passage move together and engage upon sufficient compressions of the spring, whereupon the body t~en resists further movement together of the adjacent convolutions to stiffen the spring against further compression.
For any of the above embodiments, the invention contemplates positioning one or more of the bodies between one of more adjacent convolutions of the spring, for example two of the bodies 180 apart between adjacent convolutions, or three of the bodies 120 apart.
Also contemplated~is a helical embodiment of the body, which is extendable along and between adjacent convolutions, the body in this case being generally in the form of a ramp to have along its length a progressively increasing or decreasing spaci~g from one of the convolutions for limited amounts of compression of the spring.
The foregoing and other objects, advantages and features of the invention will become apparent upon a consideration of the following detailed description, when taken in conjunction with the accompanying drawings.

1~5~'~9 Brief Description of the Drawings Fig. 1 is an elevation view, partly in cross section, illustrating a device configured in accordance with one embodiment of the invention, positioned between ad]acent convolutions of a coil spring of an automotive vehicle suspension system;
Fig. 2 is similar to Fig. 1, and illustrates an embodiment of a resilient material device positioned between adjacent convolutions of a coil spring;
Fig. 3 is a top plan view,illustrating one arrangement of devices around a convolution of a coil spring;
Fig. 4 is a top plan view, and shows another arrangement of devices around a convolution of a coil spring;
Fig; S is a top plan view of a generally helical ernbodiment of device in accordance with a ~urther embodiment of the invention, showing the same positioned between adjacent convolutions of a coil spring, and ` Figs. 6-9 illustr~te various additional embodiments o~ resilient material devices.
De~ailed Description The present invention provides devices, spacers or inserts for being mounted between adjacent convolutions of the coil springs of a suspension systern of an automotive vehicle. The devices provide progressive sti~fening or resistance to compression o the springs with increasing compressions of the springs in response to roadway bumps, undulations or severe vehicle handling conditions, but do not impede limited compressions of the springs under normal, relatively smooth driving ~ 96 conditions. In this manner, occupants of the vehicle are afforded a smooth and comfortable ride under normal driving conditions, as are usually encountered a majority o the time, yet progressive stiffening of the springs occurs under markedly undulating or severe driving conditions ~or improved roadabilit~, handling and safety. The spacers are of economical construction and convenient to install, whereby ~he same are within the economic reach of and may readily be installed by an owner of an automobile.
More particularly, with reference to the drawings there is shown in Fig. l and indicated generally at 10 a device, spacer or insert configured in accordance with one embodiment of the invention. The insert comprises a body portion 12 which may be of a rigid material such as metal, plastics, etc., or o a resilient material such as ruhber having, for example, a durometer o~ 40-110. The body portion is positionable between adjacent convolutions of a coil spring 14 of an automotive vehicle suspension system, and includes a generally flat bottom 16~ generally flat sides 18 and a humped or "M"
shaped upper end which defines a pair of h~mped or elevated portions 20 on opposite sides of a recessed or concave area 22. A pair of passages 24 through the body between the bottom and the humps receive stove bolts 26 having heads 28 and lower thread~ed ends 30 pro~ecting beyond the bottom of the space~.
The device mounts on an acti.ve convolution of the coil spring, for example one or two convolutions from the top or bottom of the sprihg~ In this connection, the body 12 is positioned between adjacent active convolutions of the spring with the bottom 16 resting 115~ t~

on the lower convolution and the upper convolution extending throu~h the concave area 22 between the humped portions 20. The stove volts 26 extend on opposite sides of and to a position beneath the lower convolution, and a plate or bracket 32 receives the threaded ends 30 of the bolts through apextures at opposite ends thereof. Lock washers 34 are placed on the bolts and nuts 36 are then uniformly tightened to clamp the body and plate together on opposite sides of the lower convolution and, in the case of a resilient material insert, until the bottom o the body begins to visually deform, as at 38.
In mounting the device lO on the vehicle coil springs 14, with the vehicle at rest a spacing d is maintained between the upper spring.convolution and the lowe-E portion o~ the concave area 22, and one or moxe inserts are ~ounted between each of one or more adjacent convolutions of each vehicle spring, for example two or three spacers per adjacent convolutions on each coil spring as shown in Figs. 3 and 4. For the case where two spacers are used, as shown in Fig. 4 the same are advantageously mounted 180 apart, for example with one being toward and one away from the wheel of the vehicle àssociated with the particular spring. Where three spacers are used, as shown in Fig. 3 the same are advantageously positioned 120 apart, for example with one of the spacers bei.ng toward the wheel associated with the particular spring.
For the situation where a single spacer is used per spring, then the same would be located toward the associated wheel, which would afford increased vehicle stability during turning or cornering It ~:~s~

is understood, however, that irrespective of the number of devices used per coil spring, the invention contemplates other orientations of the same, and that if desired more than three spacers may be used per spring and additional spacers may be mounted between other adjacent convolutions of the spring.
The spacing d between the insert 10 and the uppex spring convolution is an important feature of the invention, and prevents the insert from inter~
fering with limited compressions of the spring. To this end, the amount of spacing d is selected so that under average driving conditions on smooth roadways, as are usually encountered the majority of the time, the insert does not engage the upper convolution for limited compressions of the spring and there~orë does not impede or resist limited compressions o~ the springs, so that the vehicle's suspension system operates in its design manner and a smooth and comfortable ride is aforded to occupants of the vehicle. At the same time, since the insert normally r does not simultaneously engage the adjacent spring convolutions, it does not interfere with the standard manuactured height of the spring or vehicle. However, the amount of spacing d is also selected so that ~pon increased compressions of the spring, as would occur on very bumpy or undulating roads, when t~rning at increased speeds, during hard braking or acceleration, or when the vehicle is heavily laden, the upper convolution of the spring engages the bottom of the concave area of the insert, so that further movement together of the adjacent spring convolutions is absolutely resisted in the case where the insert is --10~

~5~

of a rigid material, or somewhat compliantly resisted and limited where the insert is resilient. Thus, under severe dxiving conditions increased compressions of the springs are resisted, whereby the stiffness o the suspension system is increased, as required, for improved vehicle handling, driveabiliky and safety.
Referring in particular to Fig. 3, for the case whexe three inserts 10 are associated with each coil spring, it has been found through experimentation that particular improvements in handling are obtained when the spacing d progressively decreases from insert to insert around a spring convolution, for example from the insert lOa to the insert lOb to the insert lOc~
It has also been found through experimentation to be advantageous to successively decrease the spacing by fractional amounts, wherein the denominator of the fraction equals the number of inserts on a single spring convolution, and the numerator initially equals the denominator but is increased by "1" for each successive insert. For example, if the insert lOa is chosen to have the maximum spacing d, then the spacing d of the insext lOa is 3/3d, that of the insert lOb is 2~3d, ànd that of the insert lOc is 1/3d. Thus, if the spacing d of the insert lOa were 1/8", then the spacing of the insert lOb would be 1/12" and that of the insert lOc would be 1/24".
For the arrangement in which two inserts are associated with each coil spring, as shown in Fig. 4, advantages in suspension improvements have been obtained when the spacing d of one of the inserts is greater than that of the other, for example when the spacing d of the insert lOd is greater than that of ~5~9~ ' the insert'lOe. In this case, the denominator of the fraction would be "2", so that the spacing of the insert 10e would be 1/2 that of the insert 10d.
To facilitate manufacture o inserts or spacers which rnay be accommodated to a variety of automotive vehicles, it is contemplated that the lengths of the inserts between the bottoms of the concave portions 22 ~ and the bottom walls 16 initially be greater than the spacings between adjacent convolutions of conventional automotive vehicle coil springs. Thus, to mount the inserts, a user simply selects the appropriate length of insert to provide a desired spacing d, and with the bolts 26 removed cuts off a selected amount o the bottom of the insert to yield the desired spacing d.
When mounted, because of the spacings d the inserts do not interfere with limited compressions of the springs, such as are encountered under average driving conditions, so that a comfortable and smooth ride is afforded to occupants of the vehicle. However, upon occurrence of severe driving conditions and increased compressions of the coil springs, and in the case where two or more inserts are used per adjacent convolutions o the springs, because of the staggered, ste~pped or progressive spacings d the spacers progressively engage the adjacent spring convolutions, in accordance with ~heir associated spacings d, to thereby progressively increase the spring~s resistance to compression.
Obviously, where'inserts are mounted between two or more adjacent pairs of convolutions of each coil spring,'the spacings d may be;selected so that progressive resistance to compression is offered frorn adjacent convolutions to adjacent convolutions, from insert to ~5~ 9~

insert around each convolution, or in any desired ~ashion. In this manner, the spacers progressivel~
increase the stiffness of the vehicle's s~lspension system in accordance with the severity of driving conditions encountered, and automatically compensate between a soft ride under average driving conditions and improved handling under severe conditions.
Thus, in use of the inserts of the invention the suspension system of a conventional automobile operates in its intended design manner under average driving conditions, yet assumes the characteristics of a heavy duty or "high performance" suspension system under severe driving conditions. To this end, the inserts enable the suspension system coil springs to variably resist the momentum of the mass of the vehicle body and frame upon encountering dips in the road, during hard braking, acc~leration and cornering, or when the vehicle is heavily laden, and provide a transitional rate o spring compression resistance to automaticalIy compensate for the sprung and unsprung forces exerted r by the mass o~ the vehicleO Due to the large amount o~ energy that the springs are able to absorb in use of the inserts, complete collapse or bottoming o the springs is prevented, and rebound of the springs after compression is lessened to an extent that a standard vehicle's suspension system has capabilities approaching those of a true pneumatic system, and shock absorbers and other portions of the suspension system are subjected to less stress and wear for longer life.
The embodiment of insert:illustrated in Fig. 2 and indicated generally at 100 is similar to that shown in Fig. 1, except that only a resilient material insert is contemplated and a hollow chamber 102 is formed ~S4~9~

centrally ~ithin a body portion 104 of the insert and is vented to atmosphere through a vent 106. As compared ~ith the device ln Fig. 1, the insert 100 offers a somewhat more variable resistance to spring compression because of the vented chamber in the resilient ~ody, the size of the vent being selected to control movement of air therethrough at a rate which yields a desired rate of,compressibility.
Fig. 5 shows a top plan view of a generally helical embodiment of solid or resilient material insert, indicated generally at 2~0, positioned between adjacent convolutions of a coil spring 14. The insert is essentially an elongate and helical arrangement of the device 10 o Fig. 1, and may be astened to the lower convolution in a similar ~anner by means of bolts, only the heads 28 of which'are shown. The height of the ins`ert is such that a spacing is normally maintained between an upper surface thereof and the upper spring convolution, and the insert is-ramp shaped along its arcuate l~ngth so that the spacing progrèssiyely decreases from one end of the insert to the other. An advantage of the helical embodiment o~ insert is its ability to provide very uniform progression of increasing spring stiffness, as the spring is compressed, over a somew~at extended portion of a convolution. Obvious'ly,',and althougk the helical spacer is shown extending'over about 240 o the convolution, it is understood ~hat it could extend a greater or lesser amount, and that more than one insert could be used per coil spring.

~4~9~

Fig. 6 illustrates another embodiment of device in accordance with the teachings of the invention, which is indicated generally at 300 and includes a resilient body portion 302. At each of the upper and lower ends of the body a pair of humps 304 define a concave area 306 therebetween~ An advantage of this embodiment is that the device does not require any hardware for being mounted on the spring. Simply, the spacer is positioned between adjacent convolutions of the spring, with one of the recessed areas 306 receiving one convolution and the other recessed area receiving the other convolution. To provide the requisite "spacing" bet~een the insert and convolutions, so as not to impede limited compressibility o the spring under normal driving conditions, a center portion of the body-.has a passage 308 therethrough. Body walls J
310 on opposite s`ides of the passage move or flex outwardly upon longitudinal compression of the body, so that the insert has only very limited resistance to longitudinal compression until a point is reached whereat normally separated longitudinal protuberances 312 move together and engage The passage 308, along with its flexible side walls 310 and the normal spacing-between the protuberances 312, prevent the insert from impeding limited compressions of the coil spring under normal driving conditions, and at the same time advantageously enable the insert to be manuall~
compressed for easy mounting on the spring. However, upon the occurrence of severe~driving conditions and increased compressions of the coil spring, the ends of the protuberances move together and engage, whereupon ~ 9~

the insert resists further compression of the spring.
It is understood, of course, that the spacing between facing ends of the protuberances, when the insert is mounted on the spring, is equivalent to the spacing d of the devices shown in Figs. 1 and 2, and that similar orientations of one or more inserts 300 on a coil spring are contemplated.
Figs. 7, 8 and 9 illustrate additional embodiments of resilient material devices which employ the general concepts and features of the device 300 of Fig. 6.
The devices in Figs. 7 9 are easily mountable on a coil spring, and by virtue of central passages there-through do not interfere with limited amounts of spring compression. However, the passa~es are arranged so that upon sufficient compression o the spring, opposing longitudinal ends or sides of the passages move together and engage, whereupon the devices then resist further compression o the spring.
While embodiments of the invention have been described in detail, various modifications and other embodiments thereof may be devised by one skilled in the art`without departing from the spirit and scope of the invention, as defined in the anpended claims.

Claims (24)

What Is Claimed Is:

1. A device for a coil spring of an automotive vehicle suspension system, comprising a body mountable between two adjacent convolutions of the spring and having a length between the adjacent convolutions which is less than the spacing therebetween for limited amounts of spring compression but greater than the spacing therebetween for increased and sufficient amounts of spring compression, whereby said body does not impede movement together of the adjacent convolutions upon limited compressions of the spring, but engages the adjacent convolutions upon sufficient compressions of the spring to thereby resist further movement together of the adjacent convolutions and compression of the spring to stiffen the vehicle suspension system.

2. A device as in claim 1, wherein said body is formed of a rigid, generally noncompressible material.

3. A device as in claim 1, wherein said body is formed of a relatively flexible material.

4. A device as in claim 1, including means for mounting one end of said body on one of the adjacent convolutions so that an opposite end of said body extends toward but is spaced from the other convolution for limited amounts of compression of the spring.

5. A device as in claim 4, wherein said opposite end of said body has elevated sides and a recessed area therebetween, and said body is mountable on the one convolution so that the other convolution is extendable through said recessed area and normally spaced from an innermost end thereof.

6. A device as in claim 4, wherein two of said device bodies are mountable between the adjacent convolutions 180° apart, and wherein said opposite ends of said bodies have respective spacings of d and 1/2d from the other convolution.

7. A device as in claim 4, wherein three of said device bodies are mountable between the adjacent convolutions 120° apart, and wherein said opposite ends of said bodies have respective spacings of d, 2/3d and 1/3d from the other convolution.

8. A device as in claim 4, wherein a plurality of said device bodies are mountable between the adjacent convolutions.

9. A device as in claim 1, wherein said body is of a relatively resilient material and has a chamber formed therein and a vent passage connecting said chamber with atmosphere, said chamber having walls which collapse to facilitate longitudinal compression of said body in response to movement together of the adjacent convolutions upon sufficient amounts of compression of the spring and said vent passage controlling the rate of movement of air into and out of said chamber to thereby control the rate of compressibility of said body.

10. A device as in claim 1, wherein said body is helical and extendable along and between the adjacent convolutions.

11. A device as in claim 10, wherein said helical body has an extension of 360° or less.

12. A device as in claim 10, wherein said he body has a thickness between the adjacent convolutions which progressively decreases from one longitudinal end of the body to the other.

13. A device as in claim 4, wherein said body is of a relatively resilient material and has a passage formed generally centrally therethrough, said body defining passage side walls which collapse to enable said body to readily compress in response to movement together of the adjacent convolutions upon limited amounts of compression of the spring, so that said body does not impede limited amounts of compression of the spring, said body defining passage top and bottom walls which move together and engage upon increased and sufficient amounts of compression of the spring, whereupon said body then resists further movement together of the adjacent convolutions and compression of the spring.

14. A device as in claim 13, wherein said body has a protuberance on at least one of said top and bottom passage walls for engaging the opposite passage wall upon compression of said body in response to the increased and sufficient amounts of compression of the spring.

15. A device for a coil spring of an automotive vehicle suspension system, comprising a body positionable between two adjacent convolutions of the spring, said body being configured so as not to impede movement together of the adjacent convolutions upon limited amounts of compression of the spring, but to impede further movement together of the adjacent convolutions upon increased and sufficient amounts of compression of the spring to thereby impede further compression of the spring and stiffen the suspension system.

16. A device as in claim 15, wherein each opposite end of said body has elevated sides and a recessed area therebetween, the adjacent convolutions being extendable through said recessed areas.

17. A device as in claim 15, wherein said body comprises a relatively resilient material and has a passage formed generally centrally therethrough, said body defining passage side walls which collapse to enable said body to readily compress in response to movement together of the adjacent convolutions upon limited amounts of compression of the spring, said body also defining passage top and bottom walls which move together and engage upon increased and sufficient amounts of compression of the spring, whereupon said body then resists further movement together of the adjacent convolutions to thereby resist further compression of the spring.

18. A device as in claim 17, wherein said body when positioned between the adjacent convolutions has a sufficient length therebetween to engage the convolutions.

19. A device as in claim 17, wherein said body has a protuberance on at least one of said passage top and bottom walls, said protuberance being spaced from the opposite wall for limited amounts of compression of the spring but moving toward and engaging the opposite wall upon increased and sufficient amounts of compression of the spring, whereupon said body then resists further movement together of the adjacent convolutions to thereby resist further compression of the spring.

20. A device as in claim 17, wherein said body has opposed protuberances on said passage top and bottom walls, said protuberances having facing ends which are spaced apart fox limited amounts of compression of the spring but which move together and engage upon increased and sufficient amounts of compression of the spring, so that said body then resists further movement together of the adjacent convolutions to thereby resist further compression of the spring.

21. A device as in claim 17, wherein a plurality of said device bodies are positionable around and between the adjacent convolutions.

22. A device as in claim 17, including two of said resilient bodies positionable 180° apart between the adjacent convolutions.

23. A device as in claim 17, including three of said resilient bodies positionable 120° apart between the adjacent convolutions.

24. A device as in claim 15, wherein said body is helical and extendable along and between the adjacent convolutions.