WO2001053138A1

WO2001053138A1 - Steering device for a vehicle in snow

Info

Publication number: WO2001053138A1
Application number: PCT/SE2001/000081
Authority: WO
Inventors: Richard HOLMSTRÖM
Original assignee: Snowcross Products Aktiebolag
Priority date: 2000-01-21
Filing date: 2001-01-18
Publication date: 2001-07-26
Also published as: AU2898201A; SE0000193D0

Abstract

The present invention relates to a slidable vehicle intended for snow, comprising a bottom plate with at least two runner-like sliding surfaces (5A, 5B), and footboards (12) which are provided in a plane above said runner-like sliding surfaces, and a flexible means (15), which is fixedly mounted in the front portion of the vehicle, with a handle (13) that the driver may hold when the vehicle is driven standing, wherein a steering device (51, 52) is arranged adjacent to each one of said runner-like sliding surfaces (5A, 5B), which steering device has at least one steering surface (51A, 52A), which may be influenced by the driver in order to steer the vehicle in the desired direction.

Description

STEERING DEVICE FOR A VEHICLE IN SNOW

TECHNICAL FIELD

The present invention relates to a slidable vehicle intended for snow, comprising a bottom portion with at least two runner-like sliding surfaces, and plates which are arranged in a plane above said runner-like sliding surface , and a flexible means with a handle, which means is fixedly mounted in the front portion of the vehicle, wherein the purpose of the handle is that the driver shall hold on to it when he drives the vehicle standing.

PRIOR ART

The present invention is primarily intended for use in connection with a vehicle, so called Snowcross, which is described in our own application WO 9845168. However, the invention is also intended for use in connection with pulkas, or the like. In said PCT publication a new kind of vehicle is described, which is intended for use in snow, which vehicle may in principle be regarded as a cheap substitute for a snowmobile. Like a snowmobile the vehicle is driven by a motor-driven belt. In contrast to a snowmobile, the steering of a Snowcross entirely lacks movable parts, and it is instead obtained by the driver moving his gravity. Another difference as compared to a snowmobile is that a Snowcross has a gliding surface which is larger than the surface with which the driving belt is in contact with the ground. At the front the sliding surface itself consists of the chassis/shell of the Snowcross, and at the back the sliding surface constitutes of a type of wide runners, which are located on both sides of the driving belt, wherein the driver stands with his feet on the runners. A flexible, wire-like device is secured at the prow of a Snowcross. At the free end of the "wire" a handle with a throttle control is provided, by means of which the driver decides the driving speed. Through holding the balance by means of the handle and by moving/distributing the gravity from one foot to the other a Snowcross may be steered in a safe and simple way. at least during most snow conditions.

However, it has proved that in connection with tightly compressed, uneven snow masses, it may be problematic to steer a Snowcross, especially if the driver is unfamiliar with the vehicle. DISCLOSURE OF THE INVENTION

An objective of the present invention is to eliminate, or at least to minimize, the above mentioned problems, which is achieved by a slidable vehicle intended for snow, comprising a bottom portion with at least two runner-like sliding surfaces, and in a plane above said runner-like sliding surface there are foot plates, and a flexible means with a handle, which means is fixedly secured in the front portion of the vehicle, wherein the purpose of the handle is that the driver shall hold on to it when he drives the vehicle standing.

Because of the described solution, a Snowcross may thus be easily steered also during very heavy snow conditions, as e.g. tightly compressed, uneven snow. Advantageously, the invention may also be used for vehicles, which are not driven by an engine, like pulkas, preferably in connection with a new type of pulka, which like a Snowcross may be steered by moving the gravity, and wherein the standing driver gets help to keep the balance by a rope or the like, which is secured in the front portion of the vehicle, preferably the prow.

According to further aspects of the invention: said steering surface constitutes a portion of an element, which is removably arranged in relation to said runner; said element constitutes a replaceable wear part; said element has a length (L), which is essentially larger than its width (B); said steering surface is integrated in the runner; said steering surface is adjustably arranged with reference to said runner; said vehicle is driven by means of a motor-driven driving belt, which is arranged between said runners.

BRIEF DESCRIPTION OF DRAWINGS

The invention will be described more in detail with reference to the accompanying drawings, of which:

Fig. 1 shows a known embodiment of a Snowcross;

Fig. 2 shows a Snowcross from below, with a steering device according to the invention;

Fig. 2 A shows a cross section through a portion of a Snowcross according to Fig. 2. Fig. 3 shows an alternative embodiment of a steering device according to the invention;

Fig. 3 A shows a side view of Fig. 3; Fig. 3B shows a cross section of the device of Fig. 3,

Fig. 4 shows an additional modification of a steering device according to the invention, as viewed from below, for a Snowcross:

DETAILED DESCRIPTION

A motor-driven vehicle with a car body unit (1) is shown in Fig. 1, in which unit a propulsive unit (2) is suspended. Every known power source which is light and strong enough may be used as a propulsive unit, e.g. small explosion motors, electric engines, and the like. The speed control of the propulsive unit (2) is performed by a manually manoeuvred throttle device (13). The throttle device (13) is steadily attached to the front portion of the vehicle by a combined throttle wire/support hose (15), which makes it possible for the driver to hold the throttle device (13) by pulling backwards, which improves the driver's balance.

The body unit (1) comprises a bottom with sliding surfaces (5) provided on the lower portion of the body unit, i.e. facing against the ground. The sliding surfaces are suitably provided with some type of coating, which improves the sliding properties of the sliding surfaces by reducing the friction between the sliding surfaces and the soft ground surfaces.

The propulsive unit (2) is connected to a driving unit (3), which is kept and steered by a suspension unit (4). The driving unit (3) comprises an endless belt (6) having a driving surface (7) facing against the soft ground surface. The total surface of the sliding surfaces (5) constitutes about 50 % or more of the total contact surface, vehicle to ground surface, (i.e. the sum of the sliding surfaces (5) and the driving surface (7). The comparatively large gliding surfaces (5) make it possible to use low-powered engines and hence smaller, more silent and less polluting engines. The endless belt rotates over a front driving wheel (18) and a rear wheel (19) while it slides on a slide frame (20). This slide frame (20) may be equipped with sliding ribbons provided between the frame and the endless belt to reduce the friction.

The endless belt (6) may include snowmobile belts with profiles of standard type, i.e. there are no special requirements on the structure of the belt, as the vehicle according to the invention has a comparatively low total weight. The endless belt (6) may have a typical width of about 230 mm. Like the snowmobile construction the endless belt (6) may be lubricated by the snow when the vehicle is used on ground surfaces covered by snow. The driving surface (7) of the endless belt has a front portion (22) and a rear portion (17), wherein the front portion makes an angle upwards in the moving direction of the vehicle, so that loose ground material, e.g. snow, is compressed under the front portion. The rear portion (17) is substantially parallel to the ground surface and is kept in a lower position than the front portion (22), i.e. sinks deeper in the soft ground material. The rear portion (17) is longer as compared to the front portion (22). The driving surface (7) may have a length corresponding to about two thirds of the total length of the vehicle, which typically lies about 1900 mm.

The suspension device (4) comprises means (8, 9, 16) for automatic height control for adjusting the position of the driving unit (3) relative to the body unit (1). The means (8, 9, 16) for automatic height control comprises front and rear means for the automatic height control.

According to a preferred embodiment the suspension unit (4) comprises front and rear dampers (8), preferably of the type which is filled with gas, which dampers at one end are attached to fastening bars (16) and at the other end to the body unit (1). The dampers continuously press the driving unit into the soft ground surfaces to obtain a proper driving force (except when the driving unit (3) is in a retracted transport position). The gas-filled dampers (8) controls thus the height of the endless belt (6) in relation to a longitudinal axis (10) of the vehicle, according to the softness of the ground surfaces. One, possibly two or more, damper/s may be used in each one of the front and rear positions. Further, the gas-filled dampers of an adjustable type may be used.

The suspension unit (4) comprises additional parallel, linked arms (9), which are so arranged that the motion of the suspension unit (4) is limited to a plane perpendicular to the general plane of the soft ground surfaces. The parallel, linked arms (9) may be attached to each other by a bridge (23). The fastening bar of the front damper is mounted in a plurality of mounting holes (11), or the like, provided on the fastening bars (16) in order to make it possible to change the geometry of the driving unit/suspension assembly in order to obtain the desired pivoting properties of the vehicle. In this connection, such factors as e.g. the driver's weight and the condition of the ground must be considered.

The sliding surfaces comprise two runner-like portions (5 A, 5B) extending on both sides of the endless belt (6) to improve the turnability of the vehicle according to the invention. The driving belt (6) is thus limited to a relative motion substantially perpendicular to the general plane of the bottom/sliding surfaces (5), which contributes to the good driving force properties of the vehicle.

The driver stands or sits on the body unit (1). which may also comprise the footboard (12), on which the driver's feet may rest. Said footboards may suitably be provided with a friction surface of some type to improve the gripping power, e.g. angle irons of aluminium or the like, which have a friction-increasing pattern on the surface. These boards also enhance the structure of the body unit (1). It may also be possible to provide some kind of footstraps on these footboards in order to increase the gripping power further.

The dampening/the downpressed effect of the gas-filled dampers (8) is advantageous to make it possible to turn the vehicle easily, as it does not have any steering means as such. The turning is obtained by moving the driver's weight from side to side, and possibly from stem to stern and vice versa.

The entire assembly with the driving unit (3)/the suspension unit (4) may be arranged to be foldable into a storage position, wherein the driving surface (7) of the endless belt (6) is located inside the lower edge (21) of the body unit (1) and in this way make it possible for the vehicle to slide freely on the ground surface. This circumstance may for instance be used to slide downhills without needing additional propulsion. The assembly with the driving unit (3)/suspension unit (4) may be located 30 to 50 mm above the lower edge of the body unit (1) in said storage position, compared to a largest lowered position of generally 150 to 200 mm at the rear wheel (19) and 50 to 100 mm below the lower edge (21) of the body unit (1) at the front wheel (18). The assembly with the driving unit (3)/suspension unit (4) may also advantageously be in storage position during transport of the vehicle, e.g. on top of or inside a car.

A vehicle according to the invention has a action radius, which among other things depends on the propulsive unit and the size of its fuel tank but is generally shorter than that of a conventional snowmobile, normally 20 to 50 km as compared to 150 km. The total weight of the vehicle of the invention may be about 30 to 50 kg as compared to more than 200 kg for a conventional snowmobile. It is thus possible for a person to lift the vehicle onto a cart or the like. The turning radius of the vehicle is also less than that of a conventional snowmobile. A vehicle of the invention is thus smaller and lighter than a conventional snowmobile, which implies that it would cause less wear damages on the environment where it is used. It also utilizes smaller and therefore more silent and less fuel consuming engines, possibly also electric engines. The low weight in combination with the sliding surfaces make the vehicle of the invention suitable for soft and deep snow. The vehicle has an approximate carrying surface against the ground of 0.85 m², which corresponds to a pressure of about 1.4 kg/dm² (including a person of 80 kg). A normal snowmobile weighing 225 kg and having a carrying surface of 0.75 m², produces a pressure of about 4.1 kg/dm^" (including a person of 80 kg). The same person on a pair of normal skis exerts a pressure against the ground of about 2.9 kg/dm². The low weight of the vehicle according to the invention in combination with the small sizes facilitates also the storage of the vehicle.

Fig. 2 shows from below a Snowcross corresponding to Fig. 1 provided with a steering device according to the invention. Said steering device consists of an angled boss element (51, 52) which is provided at the bottom side of each runner (5 A, 5B). The bosses (51 , 52) are arranged mirror-symmetrically in relation to a longitudinal centre line through the Snowcross. Thus, each one of the bosses (51, 5) is provided with one and the same angle in relation to said centre line (C). The angle α is preferably less than 45° and suitably about 5 to 40°, still more preferred between 5 and 20°. According to the preferred embodiment the bosses are arranged directly against the runner surface (5 A) and (5B), respectively, and have a width (B) exceeding the thickness (T), wherein (T) corresponds to the height with which the steering surfaces/side surfaces (51 A, 52 A) of the bosses extend above the runner surface (5A, 5B). Suitably, the width is about 1.5 to 3 times the thickness (T). The thickness (T) is preferably larger than 3 mm but preferably less than 20 mm, but more preferred between 5 and 15 mm. The length (L) is substantially larger than the width (B), preferably between 5 to 10 times the width. The boss constitutes preferably of a replaceable wear part and should therefore be attached in such a way that it may easily be replaced, suitably by means of an imbedded screw connection (53).

The steering device of the invention functions in the following way. When the driver wants to turn in a certain direction, he presses down his foot on that side at which he wants to turn. As the runners normally are spring-suspended in such a way that if the weight is distributed on both runners, they will with a light pressure rest on the snow, the increased weight distribution against one runner (5A) implies that the boss on said runner (51 ) is pressed down into the snow. As the boss is pressed against the approaching snow, its steering surface (51 A) which meets the snow will influence the vehicle with a force vector which is directed inwards against the vehicle. Said force vector will thus start a turning moment, which makes the rear portion swing outwards. wherein a counterclockwise turning motion is created, if the right foot is pressed down. The harder one foot is pressed in relation to the other, the heavier turning effect will arise.

Fig. 2 A shows that the steering bosses (50, 51) are attached by means of through-screws (53) attached with the nut portion against the footboard (12), which is provided on top of respective runner, and on which the driver thus places his feet during the driving.

Fig. 3, 3 A, 3B shows an alternative embodiment of a Snowcross with a steering device according to the invention. As can be seen from these figures, the steering devices in this case comprises steps (51, 52) and (56, 57), respectively, integrated in the sliding surface. Between each step and the surface located in front thereof an edge (51 A, 52 A) and (56A, 57A) is formed, which has the same function as the above described steering surfaces. It may suitable to provide a (not shown) wear surface in the region around the edges, as this portion is subject to larger wear than the other portions of the sliding surface. Also a steering device according to Fig. 2 may be provided in an integrated manner.

In Fig. 4 there is shown that the steering device (51, 52) may also be arranged outside the runner surface (5A. 5B) itself by placing it behind the extension of the runner.

According to this embodiment, the steering device may advantageously be adjustably arranged, so that the angle in relation to the driving direction may be adapted. Possibly, said adaptation may be arranged in such a way that it may be performed during driving, i.e. in principle as a rudder-like device.

The invention is not limited to the above description but may be varied within the scope of the patent claims below. Thus, it is for instance realized that more than one steering boss according to the embodiment shown in Fig. 2 may be provided. Further, it is possible to arrange the steering bosses of Fig. 2 movable in the vertical direction, so that the driver by means of his weight may influence them to extend below the runner surface in a desired way, e.g. by being spring-loaded upwards. As a variant to having the runners suspended in a resilience relative the driving belt portion, it is possible, above all for not motor-driven vehicles of the type pulkas, to make the centre portion of the bottom/sliding surface somewhat concave, so that the vehicle is in principle steered by rocking from one side to the other. However, it is advantageous to have some type of internal resilience, even if this resilience may be built-in directly into the runner, which helps the driver, in a soft manner, to adapt the ground pressure to the desired runner/steering device in order to perform a turn with the desired radius. It is realized that the expression "runner" implies a great variant of possible sliding surfaces, which however have in common that they are at least two and located on each side of a centre bottom portion.

Claims

PATENT CLAIMS

1. A slidable vehicle intended for snow, comprising a bottom plate with at least two runner-like sliding surfaces (5 A, 5B) and footboards (12) which are provided in a plane above said runner-like sliding surfaces, and a flexible means (15), which is fixedly mounted in the front portion of the vehicle, with a handle (13) that the driver may hold on to when he drives the vehicle standing, characterised by a steering device (51, 52) being arranged adjacent to each one of said runner-like sliding surfaces (5 A, 5B), which steering device has at least one steering surface (51 A, 52 A), which may be influenced in the desired direction by the driver steering the vehicle .

2. A vehicle according to claim 1, characterised therein that said steering surface (51 A, 52A) constitutes a portion of an element (51, 52), which is removably arranged with reference to said runner.

3. A vehicle according to claim 2, characterised therein that said element (51 , 52) constitutes a replaceable wear part.

4. A vehicle according to claim 2 or 3, characterised therein that said element

(51, 52) has a length (L), which is essentially larger than its width (B).

5.

A vehicle according to claim 1, characterised therein that said steering surface

(51 A, 52A) is integrated in the runner.

6. A vehicle according to claim 1, characterised therein that said steering surface (51 A, 52 A) is adjustably arranged in relation to said runner.

7. A vehicle according to claim 1, characterised therein that said vehicle is driven by a motor-driven driving belt, which is provided between said runners.