CA1264345A - Air suspension cab kit - Google Patents

Abstract

A novel suspension system for a cab of a motor vehicle is provided herein. The suspension is adapted to be used with a cab which is springingly-supported by shock absorbers. The suspension includes a longitudinally-extending sub-frame disposed between the cab and a main frame of the vehicle. The sub-frame includes transverse means connecting two longitudinally-extending lateral sub-frame members with fluid-actuated levelling means disposed between the transverse means and the support for such cab. Means are provided for controlling the ingress of fluid to, and the egress of fluid from, the fluid-actuated levelling means. Means are interposed between the lateral means and the cab support means for actuating the controlling means of the vehicle. In this way, the cab is maintained at a constant vertical level regardless of the vertical vibrations to which the cab may be subjected.

Description

1~4345 Thi~ application relates to an "add-on" suspension ~y~tem for supporting a cab on a vehicle, and more particularly to an "add-on" air su~pen~ion system for supporting ~uch cab.
Yieldably mounting a body with respect to a vehicle frame whereby latitude for relative movement therebetween has previous-ly been provided. For example, Canadian Patent Number 250,562 patented June 9, 1925 by A.F. Masury provided a wholly non-metallic connection and support interpo~ed between the frame and body of a motor vehicle. The support comprised a housing carried with one of such parts and having an opening in one side thereof.
A resilient arm was carried with the other of the parts and entered the opening. Yielding non-metallic material wa~ carried within the housing and engaged the end of the arm.
Canadian Patent Number 911,491 patented October 3, 1972 by N.G. Pierce provided a cab suspension arrangement involving hinging the cab at the rear, near the pitch nodal axis, rather than at the front as in conventional practice with cab-over-engine tractors. Isolation from chassis pitch was provided by mounting the front of the cab on the frame with pneumatic, hydraulic, or mechanical spring cushions having much lower spring rates than conventional mounts. The design of the front cushions provided a spring rate which resulted in a cab natural frequency substantially lower than the natural chassis pitch frequency.
Furthermore, the cab pitch was said to be alleviated without exceeding acceptable static deflection of the cab. The rear mounts were constructed not only to act as pivots in fore-and-aft 1~6434S

pitch, but also to remain comparatively rigid in other direc-tions, in order to provide cab stability. ~owever, the rear mount~ were ~aid to have ~pring rates which furnished i~olation from high frequency chassis vibration~, e.g., as noise, harsh-ness, engine and drive line vibration~.
Canadian Patent Number 990,324 patented June 1, 1976 by W.
Zajichek provided a mean~ of resiliently mounting a platform assembly on a tractor having cross-bars resiliently supported on cross beams by detachable resilient mounting mean~. The cross beams were fastened to the top portion of the transmission housings and extended transversely to support the platform assembly. The cross beams defined an inverted hat-shaped cross-section to provide ~tiffness to the beams and a similar pair of bars on the platform assembly were nestled in the beams providing the platform support. The platform assembly included a subas-sembly which included cross-bars which were fabricated to lon-gitudinal connecting means to provide a rigid structure for supporting the platform. The platform was formed with a plural-ity of plates mounted on the platform subassembly and defined aplatform surface at the operator's ~tation. Resilient i~olators were carried on the platform subassembly and resiliently sup-ported the subas~embly by resilient surfaces bearing on the upper and lower portion of the cross-bars of the subassembly. The resilient isolators rested on the cross beam~ of the platform support and threadedly-engaged a nut which was fabricated to the ~2643~S

cro~s beams, thereby providing a mean~ for quickly as~embling and disa~Qembling the platform suba~sembly from the platform support.
The platform ~upport wa~ astened to the chas~is by means of a plurality of bolt~ which were readily di~assembled from the chaQsis.
Canadian Patent Number 1,060,925 patented August 21, 1979 by A.R. Smith et al provided a system for the mounting of a cab forming the personnel compartment of a tractor on a safety frame of the vehicle. The safety frame served the function to protect the occupants of the cab in the event the vehicle was over-turned. The safety frame included a pair of front and rear, upstanding leg members ~paced longitudinally, fore and aft, on each side of the vehicle body. The passenger compartment was enclosed by a cab which was supported within the safety frame on the leg members thereof. The cab was secured to the leg members by resilient support means located generally within a common plane containing the centre of gravity of the cab and its operat-or each of which included at least one layer of elastomeric material secured between each of the leg members and the cab for resiliently supporting the cab. The layer of elastomeric materi-al was loaded only in shear by the cab. The elastomeric member was interconnected with the attachment members in ~uch a manner that the elastomeric member was loaded both in compression and shear in supporting the cab while one of the attachment members was supported from a given leg of the safety frame in a can-tilevered manner.

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Canadian Patent Number 1,148,582 patented June 21, 1983 by J.K. Ochsner provided a tractor cab which was vibration i~olated from the tractor cha~ by means of an adju~table mount sy~tem S for eliminating low frequency vibrations introduced into the cab by tire lug~. The adju~table mount system included an additional mount having an adjustable capscrew which was accessiblè to the operator. Loo~ening or tightening the ~crew changed the ~pring rate and therefore the resonant frequency of the cab on its mounts. The system allowed the cab resonant frequency to be adjusted so that it differed from the frequency of the vibration induced into the tractor chassi~ by the tire lug~ at the field-working ~peed. The isolation effectivenes~ of the mount system at higher frequencies was ~aid to remain relatively unchanged.
Canadian Patent Number 1,215,413 patented December 16, 1986 by R.G. Frey et al provided an operator's compartment that was ~upportèd for independent up and down movement independe~tly of the up and down movement of the vehicle. A connecting assembly supported the operator's compartment for independent upward and downward movement of the operator'~ compartment of the vehicle body portion so that the operator's compartment was free to move independently of the mobile body a~ the mobile body moved.
Canadian Patent Number 1,219,017 patented March 10, 1987 by R.C. Loy et al provided a ~tabilizing and isolation syYtem for mounting an operator cab on a vehicle frame. Such system per-mitted controlled vertical motion of the cab relative to the frame ~26~345 s while restraining relative rolling and pitching motion of the cab. The system had mean~ di~posed between the underside of the cab and the frame or re~iliently ~upporting the cab on the frame. A stabilizer linkage assembly was connected to the frame and the cab for re~training rolling and pitching motion of the cab relative to the frame. The as~embly included resilient means to permit relative vertical motion between the cab and the frame.
The stabilizer linkage assembly included an essentially trian-gularly-shaped plate extending in a horizontal plane between the cab and the frame. The apex of the plate was secured to the side of the cab and the base of the plate was secured to the frame.
Motion limiting means was connected to the frame and the cab for restraining vertical displacement of the cab relative to the frame in the event the re~ilient support means and the stabilizer linkage assembly should fail during a catastrophic event.
~ nited States Patent Number 3,415,535 patented December 10, 1968 by R. Gamard provided a suspension system for a vehicle having a sprung portion and an unsprung portion, a ~uspension sy~tem, and a control member responsive to variations in the su~pension system. Elastic means, separate from the suspension sy~tem proper, extended from the sprung portion to the unsprung portion of the vehicle. A control linkage was connected at one end to an intermediate point on the elastic means and at the other end to the control member. The control member was adjusted by movement of the control linkage. The elastic means thereby ~Z~ 4~i damped vibration~ in the ~uspen~ion syRtem before transmittal to the control member via the control linkage.
United State~ Patent Number 3,667,565 patented June 6, 1972 by A. Steiner et al provided a driver cab for commercial-type vehicle~ which wa~ ~pring-supported with respect to the vehicle superstructure. Such cab was spring-supported in its forward area by an approximately hairpin-shaped bending ~pring. Adai-tionally, two longitudinal guide members were provided on each side for the guidance of the driver cab which were connected with each other at one end thereof and whose other end was pivotably-connected at the driver cab and at the vehicle frame, respective-ly, whereby the torsion rod was rigidly clamped between two lower or upper longitudinal guide memberR.
United States Patent Number 3,883,153 patented May 13, 1975 by B. Singh et al provided a suspension system between the wheel mounts and chassis of a vehicle. The suspension system included a strut bar between each wheel mount and the cha~sis of the vehicle and means on the chassis which embraced each such strut bar for grippingly-engaging the ~trut bar to prevent its motion relative to the chassis whereby the wheel mounts became affixed relative to the frame and chassis of the vehicle. The means for grippingly-engaging each strut bar included a calliper-type braking clamp for each of such b~rs and a hydraulic brake actuat-ing system for operating such braking clamps.

~z643a~5 ~ nited State~ Patent Number 3,953,040 patented April 27,1976 by D.H. Unrah provided a suspension system for a vehicle which had a vehicle frame and an axle. The axle was su~pended from the vehicle frame and wa~ capable of moving toward and away from the vehicle frame. Further, the axle wa~ capable of rotat-ing about an axis disposed generally-longitudinally of the vehicle. Means were incorporated to sense the relative position of the axle toward and away from the frame. In response to this sensed relative position, the system included means to maintain the axle and vehicle frame generally within a desired range of relative positions. A cushioning, levelling and lockup sy~tem for a suspended axle vehicle which had a levelling control subsystem was provided which automatically corrected any changes in the distance between a vehicle frame and axle by communicating pressurized fluid from a pressure source to reposition fluid suspension cylinder struts. A lockup subsystem was provided which had a lockup valve which isolated spring cushioning devices from the su~pen~ion struts, to reduce suspension cushioning. The lockup subsy~tem permitted rotation about the longitudinal axis of the vehicle or roll oscillation during lockup by interconnect-ing the cylinders through a flow path across the lockup valve.
Ride cushioning could be selectively activated and deactivated.

~Z64345 United State~ Patent Number 4,079,986 patented March 21, 197~ by J. Redford provided a tie-down device for mating vehicle part~ and in particular, to a mounting arrangement for non-rigidly-connecting a cab enclo~ure and vehicle body. It included a rigid, elongate plate fixedly-attached to the ba~e of the enclosure, which extended around a marginal ~urface of the vehicle body. A plurality of pins were attached to, and depended perpendicularly from, the plate in a spaced-apart and generally-aligned relationship, and were telescopically-inserted into mating apertures positioned in the vehicle body for sliding cooperation therewith. A flexible and resilient gasket was positioned between the plate and the vehicle body marginal 8urface and received the pins through as~ociated apertures positioned therein whereby the gasket resisted the transmission of vibratory motion between the vehicle enclosure and the body.
A plurality of longitudinally-resilient fasteners were spaced-apart along the body marginal surface and had one end thereof connected with a sidewall portion of the vehicle enclosure and the other end connected with the vehicle body. A resilient member urged the ends of the fastener convergingly-together, thereby pulling the plate toward the vehicle body marginal surface and securely, yet yieldingly- connecting the cab enclo-~ure with the vehicle body.

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United State~ Patent Number 4,23~,470 patented Nove~ber 25, 1980 by W. Krau~ provided a driver compartment with spring and damping elements by which the driver compartment wa~ elastically-supported on the rest of the vehicle ma~s. Located centrallybetween the driver compartment and the rest of the vehicle wa~ a guide arrangement which guided the driver compartment in all its motions relative to the rest of the vehicle and which consisted of a vertical guide as well as two rotating guide~ couple wi~h it. The pivot axes of the guide were in the longitudinal direct-ion of the vehicle, but were transverse to it.
United States Patent Number 4,278,918 patented June 30, 1981 by B. Franco provided a tracked agricultural tractor in which the frame of the driver's cab was mounted on the tractor body by a suspension which included respective front and rear transverse suspension structures. Each of such structure~ comprised two struts formed by respective leaf springs upstanding from the vehicle body disposed ~ubstantially in longitudinal planes when relaxed, and interconnected by a cross member formed by a leaf spring lying, when relaxed, in a plane which was perpendicular to the planes of the two struts and parallel to the longitudinal axis of the vehicle. Shock absorber means were provided to damp rolling and pitching oscillations of the cab, relative to the vehicle body, due to the flexural resilience of the suspension structures.

126~345 United States Patent Number 4,390,187 patented June 28, 1983 by K. Maeda provided a vehicle levelling ~y~tem compri~ing a compression mean~ for producing pres~urized air, mean~ for accumulating the pre~urized air produced by the compres~ion means, pneumatic ~pring means dispo~ed between a chas~is and a vehicle axle for ~etting the di~tance ~etween the cha~sis and the vehicle axle by the pressurized air supplied thereto, and means for controlling the ~upply of the pres~urized air ~o that the pre~surized air was supplied from the compres~ion means only to the pneumatic spring means after a predetermined period of time had elapsed from the start of the air ~upply from the accumulat-ing means the pressurized air to the pneumatic spring means until the predetermined distance wa~ set between the chassis and the vehicle axis.
United States Patent Number 4,418,985 patented December 6, 1983 by L. Muncke et al provided a support unit for the cab of a utilitarian vehicle having a separate cab and cha~sis. The support unit included a hydraulic piston and cylinder, including a compression spring, connected between the cab and the chassis.
Fixed to the hydraulic support cylinder unit was a directional control valve which selectively directed and drained pres~urized hydraulic fluid to or from the hydraulic support cylinder unit.
The directional control valve wa~ journalled to a lever pivoted to the cab. Also journalled to the lever was an elastically-centred rod and an ab~orber element having an inela~tically-adjustàble length. Dynamic fluctuations of the distance between ~2~;~345 the chassis and cab were oppo~ed by the hydraulic ~upport cylind-er unit a~ actuated by the directional control valve. Static fluctuation~ in the distance between the chassis and the cab were accommodated by the hydraulic ~upport cylinder unit together with the absorber element.
~ nited States Patent Number 4,638,878 patented January 27, 1987 by ~.J. Komp provided a device for cu hioned support of a driver~ 8 cab on the chassis of a tractor. The device included a transversal swinging arm mounted on the cha~sis in the rear area of the cab, the transversal arm being pivoted around a lateral axis and, at its front end, acting through a ball joint on the cab at or near its centre of gravity. The device al~o included mounting points in the form of damping ~pring elements. With such a device, the cab was secured against rotation about the vertical axis and was also buffered again~t exce~sive pitching motion.
While all of the above patents are directed, in one way or another, to mounting a cab on a vehicle, none are directed to the essence of the pre~ent invention, namely the provi~ion of an "add-on" su~pension unit for the mounting of a cab on a truck.
Thus, as noted above, structure has previously been provided for:
~ a) overcoming for-and-aft pilot of highway tractor~;

126434~i tb) providing for a convenient mean~ of a~sembling a platform support on the vehicle chassis and a con-venient mean~ of mounting a platform a~embly through re~ilient means on the platform support;
(c) overcoming vibration of the cab and other part~ of the vehicle body, and the attendant resulting high noi~e level;
(d) providing an adjustable mount system for a tractor cab which reduces or eliminated cab resonance~ at the operating speed without noticeable reduction in noi~e and vibration isolation effectiveness at higher fre-quencies;
(e) increasing the degree of isolation of the cab from the frame 80 that vibration~ and impacts caused by vibrat-ing bodies used on the vehicle or transmitted from the exterior of the vehicle, are not applied to the oper-ator's cab thereby lowering the noise level in the cab and concomitantly increa ing the comfort level of the operator;
(f) providing a relatively soft, yet stable, suspension system 80 that the need to isolate the engine from the vehicle frame is either reduced or eliminated;
(g) minimizing the vibration inherent to the unsprung portion which may be transmitted to the apparatus;

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(h) providing a driver cab of commercial-type~ of motor vehicle~ which i~ relatively ~table in curve drive~
notwithstanding a relatively soft ~pring-~upport of the driver cab, and which avoid~ exce~ive cro~-titling during curve drive~ without large expenditure~;
(i) providing a ~pring ~uppressor for preventing dipping of the front end of a vehicle during braking action thereof;
~j) providing a cushioning, levelling lockup ~ystem in a ~uspenaed axle vehicle which provides for continuous load levelling and selective cushioning of road shocks, and which permit~ dampened roll oscillation while the cushioning capability i~ deactivated;
~k) providing a mounting arrangement for securely and yieldingly-connecting a vehicle cab enclo~ure with a vehicle body;
(l) providing a utility vehicle having a driver compartment which exhibits a more suitable and controlled vibration and ~hock behaviour;
~m) providing a re~ilient ~uspension for the cab of a vehicle which en~ures sufficient driver comfort, when the tractor is used on rough ground, to permit the forward speed of the tractor to be increased beyond that tolerated with previous cab Quspen~ion~;
~n) providing a ~upport unit for a cab of a vehicle in which the relative motions between cha~ and cab, ~2643AS

i.e., the vibrations and rocking motions, are largely preVentea 80 that the cab i9 thereby kept essentially free of motion;
and ~o) providing a device for a tractor cab which allows sufficient freedom of movement of the entire cab, particularly in the vertical direction, and, at the same time, in the pitching and rolling direction to reduce vibratory stresses for the driver under all operational conditions.
On the other hand, the present invention has for its main object the provision of an "add-on" suspension unit for ~ecuring to the frame of the truck to provide for an air ~uspension of a cab to such truck.
lS It is an object of another aspect of this invention to provide such an "add-on" suspension unit which al~o may provide a resiliently-mounted assembly to a cab on a truck.
It is an object of yet another aspect of this invention to provide such an "add-on" suspension unit which may al~o provide means for controlling the amplitude of vertical movement and the resiliency of the cab assembly support.
It is an object of still another aspect of this invention to provide such an "add-on" suspension unit which also may provide a cross-beam mounted on the vehicle chassis for supporting a cab assembly with means for supporting such assembly on the cross-beams.

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It is an object of a general a~pect of this invention to provide ~uch an "add-on" suspen~ion unit which i5 economical to manufacture, efficient in u~e, capable of long operating life, S and particularly adaptea for the proposed use.
By one broad a~pect of this invention a support for a cab for a truck i8 provided comprising: a plurality of cross-beams supported between the longitudinal frame members of the truck;
means connected between each lateral frame member of the truck and each respective lateral edge of a transverse platform sup-porting the cab, such means including damping means; pneumatic means dispo~ed between the cross-beamæ and the transverse plat-form inboard of the frame members; stabili2er valve means for supplying air to, and withdrawing air from, the pneumatic means;
and control means sensing the vertical position of the platform to maintain the elevation of the platform within preset upper and lower limit positions.
By another a~pect of this invention a su~pension is provided for a cab of a vehicle, the cab being springingly-supported by shock absorbing means, the suspension comprising a longitudinal-ly-extending sub-frame disposed between the cab and a main frame of the vehicle, the sub-frame including: transverse means con-necting two longitudinally-extending lateral sub-frame members;
fluid-actuated levelling means disposed between the transverse means and the support for such cab; means for controlling the ingress and the egress of fluid to the fluid-actuated levelling lZ`6434~i means; and means interposed between the lateral mean~ and the cab support mean~ for actuating the controlling means.
In such suspension, the cab is preferably supported on a platform, the platform extending longitudinally between at least two longitudinally-spaced-apart, transversely-extending frame members, the frame members supporting an hydraulic shock absorber laterally-disposed between the transver~e frame members and the main longitudinally-extending frame members of the vehicle.
The hydraulic shock ab~orber preferably is mounted with its rod end connected to a downwardly-depending ear of the tran~versely-extending frame member and with its rod end connected to a laterally-extending ear of the longitudinally-extending main frame member of the vehicle.
The fluid-actuated levelling means preferably comprises a pneumatic balloon, with the control means preferably being a pneumatic stabilizer valve, and with the interposed means prefer-ably being a vertically-movable rod, whose lower end is opera-tively-connected to a three-way pneumatic valve.
In the accompanying drawing, the single Figure shows a transverse cross-section through a vehicle fitted with the "add-on~ cab suspension device of one embodiment of this invention.
As seen in the drawing, a conventional cab 10 shown in dotted lines, was previously mounted, in a manner known to those skilled in the art, to the frame 11 of a truck. The "add-on~ air ~264345 ~uspension unit 12 interpo~ea between cab 10 and frame 11 will now be de~cribed.
The "add-on" air su~pension unit 12 includes a longitudi-nally-extending channel-shaped sub-frame 13 adapted to be dis-posed within, and secured to, longitudinally-extending main rame 11 of the truck. The cab 10 is secured to at least two tran~-verse, channel-shaped members, only one of which, 14, is shown.
The channel-shaped transverse member 14 are each provided with depending lateral ears 15 to which a hydraulic choke 16, of conventional design is mounted. The cylinder end 17 of hydraulic choke 16 is secured to ear 15 at pivot pin 18, while rod end 19 of hydraulic choke 16 is secured to laterally-outwardly-extending ear 20, which is secured to main longitudinally-extending frame 11, at pivot pin 21.
Situated transverse~y between channel-shaped longitudinally-extending sub-frame members 14 are cros~-member a~emblies, only one of which, 22, being shown. Cross-member assembly 22 includes a pair of transversely-spaced-apart, longitudinally-extending plates, indicated generally as 23, the bottom face of which are connected by a lower curved cros~-panel 24, the top faces of which are connected by an upper curved panel 25. Upper curved panel 25 and lower curved panel 24 are interconnected by a transverse plate 26. Secured to Yymmetrically-situated areas of the transverse plate on either side of the central longitudinal axis is a pair of mounting plates 27, secured to transver~e plate 12643~5 26 by bolt~ 28. Mounting plate~ 27 each ~upport a pneumatic bal-loon 29, secured between mounting plate 27 and the channel-shap~d cross-member 14. Pneumatic balloons 29 are supplied with air under pre~sure by mean~ of stabilizer valve 30. Stabilizer valve 30 includes a main line 31, and inlet line 32 and outlet line 33 to and from pneumatic balloon 29. The operation of the ~tabiliz-er valve 30 is controlled by means of a sensitive control rod 34, whose upper end 35 contacts the bottom ~urface of cross-member 14 and whose bottom end 36 is connected to a control valve lever 37.
In operation, the cab 10 is suspended by means of hydraulic chokes 16 and pneumatic balloons 29. If the cab 10 should move horizontally either upwardly or downwardly, the movement is sensed by sensitive control rod 34. This then controls stabili-zer valve 30, either to cause air under pressure to escape fromhydraulic balloons 29 ~thereby to lower cab 10), or to cause air ~ t~
under pressure to be forced op~r~the hydraulic balloon~ 29 (thereby to raise cab 10).

In this way, the cab 10 is maintained at a constant vertical level regardless of the vertical vibrations to which the cab 10 may be subjected.

Claims (7)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A support for a cab for a truck comprising: a plurality of cross-beams supported between the longitudinal frame members of a vehicle; means connected between each lateral frame member and respective lateral edge of a transverse platform supporting the cab, said means including damping means; pneumatic means disposed between said cross-beams and said transverse platform and situ-ated inboard of said frame members; stabilizer valve means for supplying air to, and withdrawing air from, said pneumatic means and control means adapted to sense the vertical position of said platform and actuatable to maintain the elevation of said platform within preset upper and lower positions.

2. A suspension for a cab of a vehicle, said cab being spring-ingly-supported by shock absorbers, said suspension including a longitudinally-extending sub-frame disposed between said cab and a main frame of said vehicle, said sub-frame including:
(a) transverse means connecting two longitudinally-extend-ing lateral sub-frame members;
(b) fluid-actuated levelling means disposed between said transverse means and said support for such cab;
(c) means for controlling the ingress and the egress of fluid to, and from, said fluid-actuated levelling means;

and (d) means interposed between said lateral sub-frame members and said cab support means for actuating said controll-ing means.

3. The suspension of claim 2 wherein said cab is supported on a platform, said platform extending longitudinally between at least two longitudinally-spaced-apart, transversely-extending frame members, said frame members supporting hydraulic shock absorbers laterally-disposed between said transverse frame members and the main longitudinally-extending frame members of said vehicle.

4. The suspension of claim 3 wherein each of said hydraulic shock absorber is mounted with its rod end connected to a depend-ing ear of said transversely-extending frame member and with its rod end connected to a laterally-extending ear of said longitudi-nally-extending main frame member of said vehicle.

5. The suspension of claim 2 wherein said fluid-actuated levelling means comprise pneumatic balloons.

6. The suspension of claim 5 wherein said controlling means comprises a pneumatic stabilizer valve.

7. The suspension of claim 6 wherein said interposed means comprises a vertically-movable rod, whose lower end is operative-ly-connected to a three-way pneumatic valve.