Land vehicles – Wheeled – Running gear
Reexamination Certificate
1999-10-04
2001-09-11
Johnson, Brian L. (Department: 3618)
Land vehicles
Wheeled
Running gear
C280S283000
Reexamination Certificate
active
06286846
ABSTRACT:
FIELD OF THE INVENTION
The present invention generally refers to a suspension system wherein two inputs are applied to a common load suspension device. In particular, the system of the invention may be applied to land vehicles; more particularly to bicycles, motor-cycles and automobiles.
In the case of two-wheeled vehicles, such as bicycles and motor-cycles in particular, the suspension system may serve to isolate the seat and handlebars from each of the front or back wheels. In a four-wheel vehicle, the system may be applied to either or both the front and/or rear axles or to the left- and right-hand side pairs of wheels.
The shock-absorber function, within the context of the present invention, is related to dampening movement transmitted from a movable part to another part supported thereon or otherwise connected thereto. Likewise, the function of the spring is to maintain support of the movable part at a predetermined height or distance from the other part, by resiliently restoring the movable part back to its original placement once the external force causing movement thereof has ceased.
BACKGOUND OF THE INVENTION
Vehicles generally have separate suspension devices comprising springs or springs and shock absorbers in combination, for each wheel or axle end. Such devices are technically well developped and relatively costly. In lightweight vehicles requiring suspension, such as in mountain bicycles for instance, the weight of the suspension device is also a relevant factor.
Some automobile vehicles use common interliked resilient devices, however for design purposes each half-spring is considered as a separate resilient element pertinent to a separate wheel or wheel system. Such separate devices are even more apparent in two-wheel vehicles. Most motor-cycles and some bicycles supplied with full suspension means use a wheel suspension system provided with a telescopically coupled sliding tube and a fork leg forming a suspension assembly with a shock absorber assembly. The size of the conventional tube/fork system requires overdimensioning to resist strong shocks which tend to bend the arrangement. Another consideration is that the optimum angle of direction does not coincide with the optimum angle of operation.
U.S. Pat. Nos. 4,265,329 and 4,627,632 suggest articulated systems that purport to overcome these problems. Further solutions are disclosed in U.S. Pat. Nos. 4,542,910 and 4,712,638 wherein a progressive linkage mechanism is incorporated between the frame structure of the vehicle and the swing arm which provides a point of progressive movement relative to the movement of the swing arm. A cushion member is coupled at such a point rather than directly to the swing arm to obtain an advantageous response relationship to movement of the swing arm. In this way, the vehicle provides a more comfortable or pleasing ride on a wider range of road conditions while maintaining a low weight. There is also in the art a wide range of simple and complex suspension systems for the back wheel.
Pedalling is the cause of a further problem in the case of bicycles. Many rear suspension are made with the pivot point at the same height as the rear wheel axle and/or about the crank assembly center. As soon as the rear axle goes above the pivot point, the chain force tends to pull the suspension into further compression. This exaggerates the suspension and creates a sagging effect that can be felt when pedalling. Furthermore, there is a loss of pedalling energy. To overcome these problems, the pivot point of many suspension units have been raised above the front chain ring. By doing this, the sag effect and the pull on the suspension is reduced or eliminated, such as suggested in U.S. Pat. No. 5,725,227 or in U.S. Pat. No. 5,685,553.
Another problem associated with this type of suspension is that the swing arm is parallel to the ground. When the rear wheel hits a bump, the resultant force is generally at a 15° to 20° angle to the ground. Thus, a substantial portion of the resultant force pulls on the swing arm and slows the rider down. In these systems, the resultant force on the rear wheel from hitting a bump is more perpendicular to the swing arm. This reduces the backward pull on the swing arm and the bicycle. However, during the compression travel of the rear wheel, these suspension systems tend to force the rear wheel in a backward direction which applies tension on the chain. Thus, the chain tension hinders the movement of the suspension, particularly at the upper end of the compression travel. U.S. Pat. Nos. 5,791,674 and 5,452,910 disclose articulated systems wherein the rear swing arm trasero does not follow a circular path through a pivot, thereby reducing forces transmitted to the frame by pot-holes and reducing the ziz-zag effect caused by pedalling. This eefect is also addressed by U.S. Pat. No. 5,785,339 which discloses a more complex system.
This brings us to the desire to simplify suspension systems by using a common resilient restoration and shock absorber for both wheels, as suggested in U.S. Pat. Nos. 5,498,014, 5,330,219, 5,772,227 and 5,417,445, as well as in U.S. Pat. Nos. 4,583,612 and 4,378,741 using different suspension device elements. However, in all these cases, the uses of a single suspension device common to both separate inputs causes cross-effects from each input to the other, therefore the inputs in such patented systems may not be considered independent of each other.
SUMMARY OF THE INVENTION
Therefore, an object of the present invention is to provide a suspension system wherein two separate input nodes may be independently coupled to a vehicle frame using a single suspension device.
Another object of the present invention is a system for use in a two-wheel vehicle or cycle for providing front and rear wheel suspension to the cycle frame by means of a single spring means, with or without complementary shock absorbing means.
A further object of the present invention is a system for use in a multiple two-wheel axle vehicle for providing independent suspension for each wheel of an axle thereof to a vehicle chassis or body through a common spring and shock absorber means.
Yet a further object of the invention is to provide a simpler and more economical suspension system.
The suspension system of the invention generally comprises a frame member to which a pair of separate input nodes are pivotable connected such as by means of a pair of input swing-arms. The frame member forms part of a generally static load system which includes the means accomodating the vehicle passengers in transit. According to the present invention, the suspension system further comprises a common swing-arm pivoting on a slider mounted to said frame member, such that the swing-arm may pivot and translate in a predetermined direction in relation to the frame member. The slider is coupled to the frame member by means of a suspension device which may include a resilient member or a resilient/shock absorber combination. The swing-arm includes two further pivots on each side of the slider pivot for coupling respective link arms to each of said nodes in a configuration such that an external force disturbing one of said nodes causes the common swing-arm to tilt substantially about the link-arm pivot corresponding to the other, undisturbed node, thereby urging the slider against the suspension device. The mechanism essentially formed by the link arms, the common swing arm and the slider provides substantially independent suspension between the frame member and each of the input nodes.
The present invention further identifies two inherently stable link arm configurations in particular. In a first embodiment, the slider is located on the frame arm above the pivot connections between the frame arm and the pair of input swing-arms. In this embodiment, the link-arms may cross-over to connect each node to the opposite end of the common swing-arm. In a second embodiment, the slider is located on the frame arm below the pivot connections between the frame arm and the pair of input swing-arms. In this second
Apariclo Leonardo Enrique Maximo
Meglio Leandro Martin
Godfrey & Kahn S.C.
Johnson Brian L.
Urguiza Santiago Adrian
Yeagley Daniel
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