March 29, 1955 J. A. ROEHRIG VEHICLE LEAF SPRING SUSPENSION Filed Dec. 9. 1952 INVENTOR. Qt AMI;
ATTORNEY 2,705,140 VEHICLE LEAF SPRING SUSPENSION John A. Roehrig, Pittsburgh, Pa., assignor of one-half to William M. Clark, Pittsburgh, Pa.
Application December 9, 1952, Serial No. 324,920 6 Claims. (Cl. 267-45) This invention relates to a vehicle spring sns ension and, more particularly, to a spring suspension of t e type in which the effective length of the spring is automatically shortened as the result of an increase in weight on the vehicle frame, or as the result of tensioning or straightening of the spring caused by road irregularities, and for the purpose of stiffening the spring under such conditions so as to avoid the possibility of breakage of the end thereof, and increase its load capacity. The present application is a continuation-in-part of my application r l ,0 filed April 29, 1952, on Vehicle Spring Suspension.
It is known in the art to provide a vehicle spring suspension with helper or auxiliary springs, or to provide means for automatically varying the effective length of the spring as the result of loading conditions or road irregularities. However, conventional spring suspensions of these types have the outstanding disadvantage of being rather complicated in construction, many requiring radius rods or requiring shackle assemblies at both ends while others include a number of auxiliary or helper springs or parts which are relatively slidable, therefore, subject to excessive wear from friction, also they are expensive to manufacture. In some types, a solid rolling shoe is used for varying the load carrying points on the leaf spring. However, such shoe, being rigid, detracts appreciably from the softness of the ride.
An object of my invention is to provide a novel vehicle spring suspension which embodies means for automatically shortening the effective length of the spring as the result of an increase in load or as the result of road irregularities, which spring comprises parts which are relatively simple and economical to manufacture and assemble.
A further object of my invention is to provide, in a Vehicle spring suspension, a shackle linkage means at the end of the leaf sp ing, Which linkage includes a yieldable rolling member for not only shortening the length of the spring but forcontributing its yieldability as a helper element or auxiliary spring in response to loading of the vehicle frame or rebound from road irregularities.
Other objects and advantages of the present invention will become apparent from a study of the following description taken with the accompanying drawing wherein:
Figure 1 is a side elevation of a spring suspension for the rear wheels of an automobile and embodying the principles of my invention;
Figure 2 is an enlarged fragmentary view of a modification of the invention shown in Figure 1; and
Figure 3 is an enlarged view of the pad and adjustable supporting element.
Referring more particularly to Figure 1 of the drawing, numeral 1 denotes a frame portion at the rear part of a vehicle having rigidly attached, underneath it, a spring supporting bracket or hanger 2 consisting of a pan spaced parallel flanges between which extends a pivotal pin or bolt 2a for supporting the forward end of a multi-leaf spring 5. The direction of the front end of the vehlcle is indicated by the arrow.
The leaves of spring 5 are held together, and the central portion of the spring 5 is mounted on (or under) the rear axle 6 by means of U-bolts or clips and brackets 7 which are rigidly held together by tightening of nuts 7a.
Underneath the rear portion of frame 1 is rigidly secured a bracket 3 similar to bracket 2 and through which bolt 3a extends for pivotally mounting the upper end of a shackle 4. The lower end of the shackle 4 is pivotally mounted by pin or bolt 4a to the rear end pornon of the longest or uppermost leaf of spring 5.
An important feature of my invention resides in the leaf of somewhat V-shape with one extremity of the leaf terminating in an eye 10a which is wrapped around and anchored to the central portion of a U-shaped member 8 which rigidly embraces spring 5, by tightening of bolts at the top extremities of the U. Of course, other suitable fastening means may be used instead for securely anchoring one end of the leaf 10 to an intermediate A portion of leaf 10 shaped element 11.
The uppermost flange of element 11 has attached 14 of resilient material,
of spring 5 at a point very close to the effective length of spring 5 is substantially that of the spring without the helper spring portion 10b.
This would be the position of the into play. However, assuming an increase or the hitting of an obstruction by the rear wheels, this increase the stiffness of the spring 5 because of the progressive shortening of its effective length, and secondly, the increase in radius of helper spring portion 10b, as it rolls on the uppermost leaf, will add to the stiffness of the spring assembly; also it will prevent the possibility of breakage of the end of the uppermost leaf of spring 5 which is a relatively weak point under heavy loading or sudden rebound. As the effective length of spring 5 is shortened, for example, as the result of rebound in hitting a hole in the road, the lower portion of leaf 10, that is, the portion extending along the rear extremities of the various leaves of spring 5 tends. to control or check the rebounding movement, thus acting somewhat as a shock, absorber. Stated differently, the rebound control or lower portion of leaf 10, which embraces the rear ends of the respective leaves tends to resist arching of spring 5 as a consequence of rebound, therefore, it checks rebound movements and provides a more comfortable or softer omitted, thus leaving ride. The limit of the helper spring action of portion 10b is reached when the extremity of portion 10b contacts the uppermost leaf spring 5, thus providing continuous contact along a substantial portion of the upper leaf, and thus shortening the effective length of spring 5 by approximately /3. When such point is reached the rubber pad 14 will have slid longitudinally along the lower surface of frame 1 in a direction towards axle 6 and its cushioning effect will resist further tendency of the spring 5 and frame 1 to come closer together. This extreme limit is rarely reached and, instead, even abnormal compression movements are checked long before the effective length of the spring has been reduced as much as /3.
Figure 2 shows a modification of the invention wherein only the rebound control portion of the additional leaf of Figure l is used, which rebound control portion is denoted in Figure 2 by numeral 13. That is, the helper part 10b of the leaf 10 has been omitted. The rearmost extremity of leaf 13 is formed into an eye 131) which wraps around the eye of spring 5 and terminates adjacent the extremity of the uppermost leaf of spring 5. The other end 13a is fastened to U-bolt 8 in the same manner as described in Figure l. The full line position shows that of normal loading, such as that without passengers, or the position prior to rebound. The dash lines show the spring at the extremity of rebound movement such as caused when the wheel drops into a hole in the roadway surface. During such rebound movement, the rebound control leaf or plate 13 will resist the tendency of abnormal reduction in the radius of curvature of spring 5 and will confine the movement to that shown in dash lines, thereby controlling rebound or providing shock absorbing action with less rebound movement, and giving a more comfortable ride.
While the vehicle spring suspension has been described as being applicable to a rear wheel suspension, it will be apparent that it is also useful for a front wheel suspension.
Although a single arcuate helper spring portion is shown at the rear end only of spring 5, it will be apparent that, if desired, two such helpers may be used instead, in which case the forward helper will be the reverse of the rear helper, that is inclined oppositely.
It will also be apparent that by making leaf 10 of stiffer material or of greater thickness, there will be less tendency for shortening the effective length of the spring in response to loading or rebound. Also element 11 may be so adjusted to be either spaced from or in contact with the lower surface of the frame 1 in the normal position (unloaded) of spring 5. It will also be apparent that if only the helper spring portion 10b-10c were desired, U-bolt 8 as well as the portion of spring 10 which embraces the ends of the leaves of spring 5 may be only an eye at the end of portion e the eye of spring 5.
100 which will encircl Thus it will also be seen that I have provided an etficient and relatively simple vehicle spring suspension which will automatically vary the length of the spring in response to loading or rebound from road irregularities in order to increase the stiffness of the spring in response to heavy loading and thus prevent the possibility of breakage at the weakest point, namely, the end of the upper leaf, and to allow the full length of the upper leaf to come mto play at the moment the additional loading is removed so as to increase the resilience of the spring and the softness of the ride; furthermore, I have provided a spring suspension which will control rebound movements somewhat as a shock absorber and which greatly stabilizes a car, particularly when travelling around bends, thus being a great aid to knee action cars, particularly, which have a tendency to become unstable around bends; furthermore, I have provided a shackle means for a vehicle spring suspension with means for varying the degree of stlffness of the spring or the softness of the ride, thereby making the spring suitable for widely different loads.
While I have illustrated and described several embodiments of my invention, it will be understood that these are by way of illustration only, and that various changes and modifications may be made within the contemplat on of my invention and within the scope of the following claims.
1. For use in a vehicle having a frame, a spring suspension for a wheel thereof comprising a multi-leaf spring and a shackle having one end pivotally connected to the spring, and the other end pivotally connectable to the frame, and a helper spring comprising a leaf of spring metal having an arcuate portion mounted so that substantially the entire length of said helper spring will provide continuous, unobstructed rolling contact with the uppermost leaf to vary the effective length of the multi-leaf spring, said helper spring having a free end located imrnediately underneath said frame and adapted to come into sliding contact with said frame to permit said helper spring to progressively increase in radius and thereby contact a greater length of the end portion of the uppermost leaf as said multi-leaf spring and frame are brought closer together to progressively shorten the effective length of the multi-leaf spring.
2. In a vehicle having a spring suspension for a wheel thereof, comprising a multi-leaf spring connected to said frame and having a shackle pivotally mounting one end of said spring to said frame, a helper and rebound control leaf of spring metal having one end rigidly secured to an intermediate portion underneath said multi-leaf spring and a free end above said rnulti-lcaf spring which is adapted to come into sliding contact with respect to said frame as the result of movement of said multi-leaf spring towards said frame, an intermediate portion of said leaf closely encircling the pivotal connection between said rnulti-leaf spring and shackle, the free portion of said leaf having an arcuate portion providing continuous, unobstructed rolling contact throughout its entire length with the uppermost leaf of said multi-leaf spring as the rnulti-leaf spring is moved towards the frame whereby as a consequence of said sliding contact of the free end with the frame, the radius of curvature of said arcuate portion will be progressively increased so as to progressively contact throughout its length a greater length of the end portion of the multi-leaf spring, and thereby progressively decrease its effective length and increase its stiffness.
3. Apparatus as recited in claim 2, wherein said free end of the helper and control spring leaf is provided with adjustable means for varying the distance between the free end and the frame, whereby the stiffness of the rnulti-leaf spring in response to a given spring movement may be varied.
4. Apparatus as recited in claim 2 together with sliding means adiustably connected to the free end of said helper spring, including adjusting means for varying the distance between said sliding means and frame to thereby vary the stiffness of the multi-leaf spring, and a pad of resilient material secured to said sliding means and adapted to provide cushioned sliding contact with said frame.
5. A spring suspension for supporting a wheel of a vehicle and including a rnulti-leaf spring extending longitudinally with respect to a longitudinal frame member of said vehicle to which it is connected, and having a shackle pivotally connected to one end thereof and to the frame, a helper and control spring comprising a leaf of spring metal having an intermediate portion mounted so as to snugly embrace one of the ends of the various leaves of said multi-leaf spring and another portion terminating in a free end adapted to provide sliding contact with said frame and having an arcuate portion adjacent said free end arranged to provide unobstructed rolling contact with the uppermost leaf of said multi-leaf spring as the result of movement of said multi-leaf spring towards said frame and sliding movement of said free end underneath said frame, whereby the effective length of said uppermost leaf is progressively decreased, the end of said helper and control spring opposite said free end being rigidly fastened to an intermediate portion of said multi-leaf spring.
6. In a vehicle wheel spring suspension comprising a rnulti-leaf spring and a shackle having one end pivotally connected to one end of said spring and the other end pivotally connected to the frame of a vehicle, the other end of said spring also connected to said frame, a rebound control spring leaf having one end rigidly secured with respect to an intermediate portion of said rnulti-leaf spring, the other end of said leaf provided with an eye portion encircling and forming part of the pivotal eye connection between said end of the multi-leaf spring and said shackle, the intermediate portion of said rebound control leaf closely embracing one of the ends of the various leaves of said multi-leaf spring, whereby rebound movements tending to separate said spring from said frame and to 35 decrease the radius of curvature of said multi-leaf spring will be resisted by bend' of said spring leaf so as to 1,858,930 provide shock-absorber-like action. 1,870,787
References Cited in the file of this patent UNITED STATES PATENTS 5 Zgggg 1,597,704 Young Aug. 31, 1926 453,647 1,606,386 Rouanet Nov. 9, 1926 6 Hoover May 17, 1932 Smith Aug. 9, 1932 FOREIGN PATENTS Great Britain June 2, 1931 Great Britain Sept. 21, 1937 Germany Dec. 12, 1.927