Wheel suspension for e.g. golf cart, has link element acting as lever arm by virtue of rotation point situated at distance from imaginary straight line intersecting wheel axles and in plane transversely to extent of moment axis

(54) Title: Wheel suspension (56) Publications cited. US A 4,056,158 (47) Summary:

The present invention relates to a wheel suspension for mounting to a body (3) of a vehicle, which in its direction of propulsion is adapted to be able to climb up obstacles (7), the wheel suspension (1) comprises a link element (9) arranged rotatably about a rotation point (R) , to which a rotation point (R) can be applied via the body (3) to a force (Gx) for driving, the link element (9) comprises a first and a second wheel shaft (11, 13), the second wheel shaft (13) serves as a torque shaft (X) around which the link element (9) tends to rotate when the first wheel shaft (11) is applied a force (F) in the direction opposite to the direction of travel.

The link element (9) acts as a lever in that the point of rotation (R) is located at a distance from an imaginary straight line (L) intersecting the first and second wheel axles (11, 13) and in a plane transverse to the axis of the torque (X).

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SUMMARY

The present invention relates to a wheel suspension for mounting to a body (3) of a vehicle, which in its direction of propulsion is adapted to be able to climb up obstacles (7), the wheel suspension (1) comprises a link element (9) arranged rotatably about a rotation point (R) to which a point of rotation (R) can be applied via the body (3) to a force (Gx) for propulsion, the link element (9) comprises a first and a second wheel shaft (11, 13), the second wheel shaft (13) serves as a torque shaft (X) around which the link element (9) tends to rotate when the first wheel shaft (11) is applied a force (F) in the direction opposite to the direction of travel.

The link element (9) acts as a lever in that the point of rotation (R) is located at a distance from an imaginary straight line (L) intersecting the first and second wheel axles (11, 13) and in a plane transverse to the axis of the torque (X).

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BACKGROUND OF THE INVENTION

The present invention relates to a wheel suspension according to the preamble of claim 1.

The invention can be attributed to the vehicle manufacturing industry.

BACKGROUND OF THE ART

Today, there are wheel suspensions where wheels are stored at a link element and the link element itself is stored around a point of rotation at the vehicle body. Such a wheel suspension is described in the Swedish patent application SE SE 0102878-6, in which the wheel suspension is designed to be able to absorb vertical movements which are applied to the wheels as they are driven over bumps so that a smoothing time is achieved for the vehicle.

WO 02/062285 describes a wheel suspension comprising a link element which can be applied to a force to improve the climbing characteristics of a vehicle. The link element comprises a lifting wheel which lifts the front portion of the vehicle by means of a force applied to a lever structure. The link element is a complementary structure and is separated from the vehicle's main wheel. The design means that a user must perform an additional handgrip to allow the vehicle to climb.

US 4,056,158 A shows a wheel suspension for mounting on a vehicle adapted for climbing. A second wheel shaft serves as a torque shaft about which the linkage element of the wheel suspension tends to rotate when a forward wheel shaft is applied a force in the direction opposite to the direction of travel.

The present invention seeks to find a solution that improves the climbing properties of an obstacle, such as a curb, for example.

528 676 while allowing the simplest possible handling of the vehicle. At the same time, the present invention seeks to provide a simple structure that effectively provides an intrinsic suspension function without complementary suspension elements.

This is solved by the present invention by means of the wheel suspension described in the introduction, the wheel suspension being characterized by the features set forth in the characterizing part of claim 1.

In this way, the required driving force can be utilized to also lift the wheels of the first wheel shaft. This is achieved by a lever effect, in which rotation of the link element is effected by the force applied at the point of rotation, that is, a vehicle pushing linear force in the direction of propulsion, and the distance provided for the lever of the link element.

A downward rotation point below the center of the wheel axles creating said leverage effect also contributes to a softer propulsion of the vehicle since the pushing force is to some extent converted into a lifting force. Thus, no resilient element is needed to counteract the rotation of the link element.

Alternatively, a first distance between the first wheel axis and the point of rotation corresponds to a second distance between the second wheel axis and the point of rotation.

Thus, a user can align the wheels of the suspension with the direction of travel without regard to the order of the front and rear wheels being set and at the same time obtain the desired leverage effect. The turning speed of the vehicle will also be good.

Preferably, a first distance between the first wheel axis and the point of rotation differs from a second distance between the second wheel axis and the point of rotation.

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In this way, the leverage effect can be achieved even on steep climbs, with maintained torque generating distance, since the second distance between the second wheel axis and the point of rotation is shorter than the first distance between the first wheel axis and the point of rotation.

Conveniently, the wheels are also arranged to overlap each other. In this way, the pivotability is optimized.

Preferably, the surface of the respective wheels has a side-mounted circumferential surface for contact with the roadway, the wheels mounted on the wheel axles in such a way that the circumferential surfaces are facing each other.

This reduces the tendency to distort the wheel set when in contact with an obstacle.

Conveniently, the body is provided with stop means arranged for engagement with the link element to prevent the link element from rotating over so that the first wheel axle does not occupy the position of the second wheel axle.

In this way, a user can lift the vehicle body without having to rotate the link element to its original position before reduction.

Alternatively, the vehicle is a walker.

Preferably, two wheels are arranged at the respective first and second wheel axes.

Conveniently, the wheel suspension is arranged not pivotal at the vehicle, however, allowing the link element to rotate about the point of rotation.

BRIEF SUMMARY

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In the following, the present invention will be explained in more detail with reference to the accompanying drawings, in which:

FIG. 1 shows a wheel suspension according to a first embodiment;

FIG. 2a-2b show a wheel suspension according to a second embodiment;

FIG. 3a-3b show a wheel suspension according to a third embodiment;

FIG. 3c shows a wheel suspension from above;

FIG. 4 shows the wheel suspension of FIGS. 3a-3b with preferred aspect ratios;

FIG. 5a-5b show a principle sketch for climbing;

FIG. 6 shows a fourth embodiment; and FIG. 7 shows a fifth embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will now be described as exemplary embodiments. For the sake of clarity, components of no significance to the invention have been omitted from the drawing. The same details shown in several figures may in some cases lack reference numerals, but correspond to those that have reference numerals.

FIG. 1 shows a wheel suspension 1 according to a first embodiment. The wheel suspension 1 is mounted on a frame 3 comprising a fork 5 of a vehicle (not shown). The vehicle is arranged in its forward direction to be able to climb obstacles 7, such as a curb. The wheel suspension 1 comprises a link element 9 arranged rotatably at the fork 5 about a rotation point R. For propulsion of the vehicle, a force Gx is applied to the body 3 and thus via the fork 5 also to the point of rotation R. The link element 9 in the form of a rectangular plate comprises a first (front) and a second (rear) wheel shaft 11,13 stored at the front of the link element 9 Rear portions 15, 17. A front and rear wheels 19, 21 are arranged in line with and after each other and are rotatably arranged at respective wheel axles 11,13. The rear wheel shaft 13 serves as a torque shaft X about which the link element 9 tends to rotate as the front wheel shaft 11 is applied via the front wheel 19 to

528 67Ö force Fx in direction mainly opposite to direction of travel. This force Fx and the force Fy are components forming the force F. The force F generated upon impact of the curb contributes to a twisting torque M about the rear wheel shaft 13 lifting the front wheel 19.

The link element 9 is arranged to act as a lever in that the point of rotation R is located at a distance b from an imaginary straight (straight) line L intersecting the first and second wheel axles 11, 13 and in a plane transverse to the extent of the torque axis X. Thus, in order to create the lever b, the point of rotation R has been placed below the intended straight line L. The pushing force Gx and the lever b create a linking element 9 lifting torque around the rear wheel shaft 13. This torque is supplemented by an additional torque created by the force F acting on the front wheel 19 and the distance a. In the theoretical case, the front wheel 19 of the wheel suspension 1 encounters an obstacle 7 at least at the same height as the height of the wheel axles 11, 13 (or the wheel). 19 radius) above the support U, the distance a would be equal to zero. Thus, only the lifting torque (torque M) created by the force Gx and the distance b would cause the wheel suspension 1 to rotate about the second wheel shaft 13.

Both wheel axles 11, 13 are in FIG. 1 positioned symmetrically around the point of rotation R and since the wheels 19,21 are arranged one after the other in line, the pivotability of the vehicle is not affected when obstruction. According to this embodiment, a first distance d between the first wheel axle 11 and the rotation point R corresponds to a second distance c between the second wheel axle 13 and the rotation point R.

FIG. 2a-2b show a side view and a front view of a wheel suspension 1 according to a second embodiment. The first and second wheel axles 11, 13 are arranged at the link element 9 parallel to each other. The first wheel axle 11 includes a front wheel 19. The second wheel axle 13 is divided into two sub axles, each carrying a rear wheel 21. The rear wheels 21 are arranged behind the front wheel 19 as seen in the direction of travel. The second wheel shaft 13 (the two partial axles) is offset relative to the first wheel shaft 11 seen in the direction of travel, so that at the shafts 11, 13

528 676 mounted wheels 19,21 fall partially side by side and on each side of a point of rotation R intersecting and parallel to the direction of travel along longitudinal thought line. Alternatively, two front wheels may be mounted on the first wheel axle 11.

FIG. 3a-3b show a wheel suspension 1 according to a third embodiment. A front and rear wheels 19,21 are arranged at a link element 9. The wheels 19, 21 are located partly side by side and are mutually offset in the direction of travel. FIG. 3a shows the wheel suspension 1 from above. The rotation point R of the wheel suspension 1 consists of a rotation shaft arranged on a hand-driven vehicle (for example a walker, stroller) (not shown) fork 5. The fork 5 is pivotally arranged at the frame 3 of the roller atom at a pivot shaft S. The link element 9 has a V-shape and supports the front and rear wheels 19, 21 at the respective link end, as is clear from FIG. 3b.

FIG. 3c shows a wheel suspension from above. The pivot axis here is a ball joint 20 simultaneously constituting a point of rotation R and pivot axis S (instead of allowing the point of rotation to be a horizontal axis in the transverse direction of travel from the pivot axis) and the two wheel axles are symmetrically positioned on each side of the point of rotation R. of the wheels 19,21 permits an optimal pivot of the vehicle. At the same time, the wheels are placed overlapping each other and so wide that the pivotability is allowed to be optimized without affecting the structure of the wheel suspension 1.

FIG. 4 schematically shows the wheel suspension 1 in FIGS. 3a-3h with preferred linkage conditions. In order to create lifting lever power to improve the climbing characteristics, the point of rotation of the link element 9 (link arm) 9 is placed a distance b below the intended, intersecting the first and second wheel axes 11,13 and in a plane across the extension of the torque shaft X, the straight line L.

The ratio of the front distance d between the front wheel shaft 11 and the rotation point R and the rear distance c between the rotation point R and the rear wheel shaft 13 is such that the front distance d is greater than the rear distance c.

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A simplified equation for calculating the rotation about X can be defined as:

F * a + Gx * b-Gy * c = 0;

Where F is the force absorbed by the wheel suspension 1 when traveling against an obstacle 7. F is divided into the components Fy (lifting force) and Fx (a vehicle in the direction of travel counteracting force).

Gx is the force that affects the vehicle in the direction of travel. Gy is the force applied to the vehicle in the direction of the substrate U. In a walker, a user's body weight (not shown) will affect the point of rotation R with a force G (not shown) for moving the roller atom. This force G is divided into the components Gy and Gx, where Gx is defined as the pushing force.

The distance h is the lever created to improve the climbing characteristics of the rollat. The distance b is greater than 0 and smaller than the radius r of the rear wheel 21. The distance b is between 2-90%, preferably 25-70%, of the radius r.

F * a + F * cosa * h-Gy * c = 0;

The angle a is determined by the ratio of obstacle height d to the radius of the wheel. That is, the radius of the wheel is equal to the obstacle height, the angle a is equal to 0.

Fy = F * sin a;

Where Fy is a lifting force for the wheel suspension 1.

Since the distance c is smaller than the distance d, the weight of the user is largely distributed to the rear wheel 21, which further improves the suspension of the wheel suspension 1.

528 676 climbing characteristics because the front wheel tends to lift more easily from the ground due to the lower load.

While the point of rotation is moved down the line L, the wheel suspension 1, when ascending, climbs over obstacles as the link element falls close to the vertical, or falls so far that the point of rotation R falls in front of both the first wheel axle 11 and the second wheel axle 13 seen in the direction of travel. in relation to the wheels 19, 21 in the backward position. This also helps to optimize the pivotability of the wheel suspension 1, that is, when both wheels 19, 21 fall behind the rotation point R.

FIG. Figures 5a-5b show a principle sketch for climbing over an obstacle 7. The front distance d between the first wheel axle 11 and the rotation axis R is substantially greater than the rear distance c. This is to maintain the leverage effect even when the wheel suspension 1 climbs (see FIG. 5b). . By allowing the rear distance c to be smaller than the front distance d and allowing the distance between the wheel axles 11, 13 to be as small as possible, a good turning function of the wheel suspension is achieved. Because the distance c is small, during the climb the rotation point R can be maintained in position below the rear wheel shaft 13, whereby the lever b "is maintained, however slightly shorter than the lever b 'at the non-climbing position of the wheel suspension 1 (see figures b shown in FIGS. 5a and 5b). 'and b').

In this way, the leverage effect can be achieved even on steep climbs, with substantially retained distance b, since the rear distance c between the second wheel shaft 13 and the rotation point R is shorter than the front distance d between the first wheel shaft 11 and the rotation point R.

FIG. 6 shows a fourth embodiment of the wheel suspension 1. The surface of the respective wheels 19, 21 has a side circumferential surface 22 for contact with the support U (the roadway).

The wheels 19,21 are mounted on the wheel axles 11,13 in such a way that the circumferential surfaces 22 are facing each other. This reduces the tendency to distort the wheel set

528 676 in contact with an obstacle 7 because the contact point of the front wheel 19 with the support U and the pivot shaft S has a distance therebetween as small as possible.

FIG. 7 shows a fifth embodiment of the wheel suspension 1. According to this embodiment, the front wheel 19 which occupies this first contact with the obstacle 7 has a larger diameter, the rear wheel 21. Even if the obstacle 7 is higher (see FIG. 7) than the front wheel 19 19 radius, the driving force Gx at the point of rotation R and the wheel suspension 1 provide the lever b a rotating torque M such that the front wheel 19 tends to climb up the obstacle 7. The body 3 is provided with a stop means (rubber cushion) arranged for engagement with the link element 9 to prevent the link element 9 from rotating over. That is, so that the first wheel axle 11 does not take the position of the second wheel axle 13 when a user lifts the vehicle. The wheel suspension is mounted on a off-road handheld vehicle, such as a stroller or jogging trolley (not shown).

The present invention is not to be construed as limited to the above-described embodiments but modifications and combinations thereof may occur within the scope of the present invention. The wheel suspension can be used on a walker, golf cart, stroller, cart, transport wagons of various kinds or other vehicles such as rail vehicles, cable cars, etc. The wheel suspension is not limited to being pivotal, for lateral turning, arranged at the vehicle. The wheel suspension including the point of rotation may also be fixedly mounted to the vehicle, that is, non-pivotally arranged, for example at the vehicle in a suitable location where a second steerable wheel of the vehicle satisfies the steering of the vehicle sideways. The wheel suspension can also be provided with rails, skis, etc. instead of wheels, for example a snowmobile or similar, in which the word wheel axle is replaced with the word axle.

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