WHEEL SUSPENSION SYSTEM FOR VEHICLES

FIELD OF THE INVENTION [0001] The present invention relates to vehicles. More particularly, the present invention relates to a frontal suspension system for vehicles.

BACKGROUND OF THE INVENTION

[0002] Small and lightweight vehicles such as golf-course carts and airport corridor transport vehicles as well as scooters used by people with mobility limitations are expected to provide passengers with safe, stable and easy steering conditions as well as comfortable, tremble-free traveling conditions. Some of the small and lightweight vehicles (referred to from hereinafter in the text as "scooters") are designed to travel at times over rough terrain, where various road and field obstacles are expected and have to be over come. It is desired that for rough-terrain designed scooters the steering and comfort conditions obtained when traveling over smooth terrain be maintained when traveling in un-smooth environments.

[0003] For safe and stable steering of standard road-worthy vehicles (such as common commercial city-utility cars and sport-utility-vehicles, known as SUVs) the Ackerman steering geometry of linkage of wheels is commonly adopted. In addition, the steering system includes an inclined and Caster angled steering-knuckle mechanism with the wheels deployed in a Camber angel. To dampen the vibrations and oscillations sensed by passengers, standard road-worthy vehicles are equipped with shock absorbers that reduce tremors. In many standard road-worthy vehicles a McPherson strut suspension system integrates the steering with shock absorber mechanisms.

[0004] Given the restriction of the small axial span between the front wheels of scooters there are engineering difficulties in integrating the steering mechanism with reliable shock absorber mechanisms in a unified unit, as was previously described. In scooters a MacPherson strut suspension system does not dampen rough terrain-caused quivers and motions, making the shock absorbent of the system dysfunctional.

[0005] A method to dampen the quivers and motions of some standard road worthy vehicles is the use of a trailing-arm wheels suspension system, usually in use on the rear

axles. The draw back with a trailing-arm wheels suspension system, especially in case of a short wheel axis, is the difficulty of integrating the system with an inclined and Caster angled front wheels positioning system. Attempts of scooter manufactures to produce scooters using a trailing-arm wheels suspension system lead to vehicles having malfunctioning steering systems and difficulties with the braking mechanisms of the vehicles. The present invention solves the above-mentioned problems.

SUMMARY OF THE INVENTION

[0006] There is thus provided, in accordance with embodiments of the present invention, a wheel suspension system for a chassis of vehicle which comprises at least two wheel assemblies. Each wheel assembly comprises a trailing arm which is substantially aligned with forward motion direction of the vehicle, having a first and second ends, pivotally connected at the first end to the chassis of the vehicle and coupled to a wheel axis at a location adjacent the second end. A shock absorber is coupled to the chassis or an extension thereof, the shock absorber coupled to the wheel axis, for damping motion of the wheel axis due to shocks exerted by a rough surface on which the wheels travel.

[0007] Furthermore, in accordance with some embodiments of the present invention, the shock absorber comprises an elongated shock absorber. [0008] Furthermore, in accordance with some embodiments of the present invention, the shock absorber and the trailing arm define an angle in a range of 70 to 110 degrees.

[0009] Furthermore, in accordance with some embodiments of the present invention, the wheel assemblies are coupled to a steering mechanism.

[0010] Furthermore, in accordance with some embodiments of the present invention, the steering mechanism comprises steering knuckles.

[0011] Furthermore, in accordance with some embodiments of the present invention, a steering rod is connected to the steering knuckles.

[0012] Furthermore, in accordance with some embodiments of the present invention, a steering rod is connected between two adjacent wheel suspension systems. [0013] Furthermore, in accordance with some embodiments of the present invention, a steering shaft is connected to the steering rod.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to better understand the present invention, and appreciate its practical applications, the following Figures are provided and referenced hereafter. It should be noted that the Figures are given as examples only and in no way limit the scope of the invention. Like components are denoted by like reference numerals.

[0015] Fig. 1 illustrates a view from above of a chassis of a scooter with a steering mechanism having a frontal wheels suspension system, in accordance with an embodiment of the present invention. [0016] Fig. 2 illustrates a view from the side of the chassis of the scooter shown in Fig. 1.

[0017] Fig. 3 illustrates a detailed view of the frontal wheels suspension system of the chassis of the scooter shown in Fig. 1 and fig. 2.

[0018] Fig. 4 illustrates a view from the side of the frontal wheels suspension system of the chassis of the scooter shown in Fig. 1 and fig. 2.

[0019] Fig. 5 illustrates a detailed view of the connection between a steering-knuckle, a shock absorber and a trailing arm in the frontal wheels suspension system of the chassis shown in Fig. 4 and Fig. 5.

DETAILED DESCRIPTION OF EMBODIMENTS

[0020] The difficulties of constructing a mechanism for a scooter that integrate a reliable steering mechanism with a dependable shock absorbent were previously described. The present invention provides a method for utilizing a trailing-arm wheels suspension system integrated with an Ackerman steering geometry of linkage of wheels with a Caster angled steering-knuckle mechanism deployed in a Camber angel, to be used in a scooter vehicle.

[0021] The frontal wheels suspension system for vehicles in an embodiment of the present invention comprises two wheel assemblies. The assemblies have two parallel, frontal protruding trailing-arms (one for each assembly), coupled to the chassis of a vehicle having a relatively small distance between the arms. To the frontal edge of each of the trailing-arms a steering-knuckle is perpendicularly connected or coupled (the

terms "connect" and "coupled" are used in the text from hereinafter interchangeably) by a steering-knuckle to an axis-bar. In close vicinity of each of the steering-knuckle an elongated shock absorber is pivotally coupled to the axis-bar. The shock absorber comprises an elongated cylinder and a sliding piston inside compressing either a hydraulic fluid or air or, alternatively, the shock absorber comprises an elongated hard, coiled-spring. The shock absorbers axe coupled at their raised end to a chassis- connected elevated bar-frame by pivots. The projection of the shock absorber and the trailing arm in each wheel assembly define an angle in a range of 70 to 110 degrees. The kingpins (through the steering-knuckles) and the pivotally-coupled shock absorbers are connected to a steering rod. The connections enable the steering the scooter in a desired angle while simultaneously dampening the vibrations and tremors caused by the traveling surface conditions. The above described wheel assemblies in an embodiment of the present invention enables substantially accurate perseverance of a pre-determined Camber angle and steering-knuckle inclination. In addition, the caster angle of the front wheels is maintained in a predetermined angle. The previously described functions of the steering and shock absorbing mechanism-components provide a scooter with stable and comfortable steering characteristics.

[0022] Reference is now made to the Figures in which an embodiment of the present invention is illustrated: [0023] Fig. 1 illustrates a view from above and Fig. 2 a view from the side of a chassis of a scooter 10 with a steering mechanism having a frontal wheels suspension system 14, in accordance with an embodiment of the present invention.

[0024] Fig. 3 and Fig. 4 illustrate a frontal and a side detailed view, respectively, of the frontal wheels suspension system 14 of the chassis 12 shown in Fig.l and Fig. 2. [0025] Fig. 3 and Fig. 5 illustrate a detailed view of the connection between a steering-knuckle 36, a shock absorber 30 and a trailing arm 20 in the frontal wheels suspension system 14 of chassis 12 shown in Fig. 4 and Fig. 5.

[0026] For a better understanding of the embodiment of the present invention the three detailed Figures (3, 4 and 5) should be viewed in parallel while reading the descriptive text that follows.

[0027] Two parallel frontal protruding trailing arms 20 are each connected to a frontal bar-frame 22 of the body of the chassis 12 by a perpendicular tube with an inside-bar

connector, serving as a pivot 24. (In another configuration, not shown, the trailing arms are connected to the frontal bar-frame 22 and extend towards the rear of the vehicle.) The frontward extending edge of arms 20 are each connected by a perpendicular tube with an inside-bar connector, serving as a pivot 26. The inside bar of pivot 26 extends side-way, to both sides of the chassis and serve as a wheel steering axis 27. Shock absorbers 30 bridge between wheel-axis 27 and a vertically extended bar-frame 32 that protrudes from frontal bar-frame 22. Each of the shock absorbers 30 is connected to bar- frame 32 by a perpendicular ring with an internal bar connector 34 that serves as a pivot. [0028] The four pivot-connections, 24, 26, 29 and 34 act in unison to enable the swaying of chassis 12, thus to dampen vibrations and quivers of the scooter when traveling on rough terrain. Vertical momentum-forces "are neutralized" by the up and down motion causing the stretching and relaxing of shock absorbers 30.

[0029] Steering knuckle 36 is connected on both sides of chassis 12 to wheel-spindle 28, which in turn, is connected to wheel 38. Steering knuckle 36 is connected to wheel steering axis 27 by a king pin 31 that enable the angular movement of wheel 38. The two adjacent wheel suspension systems 14, on the frontal side of chassis 12, have steering knuckles 36 connected to each other and to the steering shaft 40 by a pivotal connection to steering rod 42. The connections enable the controlled maneuvering of the wheels in accordance with the Ackerman steering principle. Both shock absorber 30 and steering knuckle 36 are closely connected to bar 42, forming a longitude McPherson- strut-type suspension system. The inclination angle of steering knuckles 36 enable stable and comfort driving.

[0030] In another embodiment of the present invention, the steering knuckles are perpendicularly coupled to trailing-arms along the trailing arms (not reaching the protruding end).

[0031] In another embodiment of the present invention, the trail-arms are coupled to the chassis of the scooter from the advancing-direction side in the direction of the rear of the vehicle and the steering knuckles are perpendicularly connected to the trailing-arms at the end or along the length of the trailing-arms.

[0032] It should be clear that the description of the embodiments and attached Figures set forth in this specification serves only for a better understanding of the invention, without limiting its scope.

[0033] It should also be clear that a person skilled in the art, after reading the present specification could make adjustments or amendments to the attached Figures and above described embodiments that would still be covered by the present invention.