Steering system for vehicle with runners. Field of the invention

The present invention relates to a vehicle according to the preamble of the independent claim.

Background of the invention

Today, vehicles are known for outdoor use on snowy or icy grounds. There are many types of such vehicles, with or without motor, including sleighs for downhill use in particular, such as bob sleighs having a frame with a seat to which two non-steering runners, or in other words "skis", are provided on each side of the seat attached to the frame and one additional single frontal steering runner is provided. A steering wheel is attached to the frontal steering runner by means of a common steering axle providing the sleigh to be steered by a user sitting on the seat by means of turning the steering wheel and consequently the steering axle to which the frontal runner is attached. Such a sleigh is according to an aspect similar to a snow mobile without a motor, but normally much simpler in other aspects as such as steering gears. A drawback with a vehicle, in particular a sleigh having runners, where the rear runners are non-steering, are that the latter do not assist steering. For instance, a sleigh having a frontal steering runner and two non-steering rear runners can lack a feeling of direct steering response. Thus, an object of the present invention is to provide an improved sleigh which assists steering.

Summary of the invention

The above-mentioned object is achieved by the vehicle of the present invention according to the independent claims. Embodiments are set forth in the dependent claims. According to a first aspect, there is provided a vehicle having a steering. The vehicle comprises a frame provided with a seat thereon, a steering wheel provided in a front, or frontal, part thereof, and runners attached to the frame. The runners are arranged to provide at least rear runner steering of the vehicle on a surface onto which the vehicle can be run.

In this way, there is provided a vehicle having improved steering by means of rear runner steering. Herein, the term "rear runner steering" means that the rear runners are employed for steering.

Herein the term "vehicle" includes but is not limited to a sleigh for snow or ice, or any other surface onto which the vehicle can be run. Herein, the term "runner" includes, but is not limited to skis.

The vehicle according to the present invention can also be provided with runners in the form of wheels for other surfaces than snow or ice, such as conventional road surfaces. According to another aspect of the present invention, the vehicle typically being a sleigh has four runners arranged to provide four runner steering. The runners can be arranged in two separate steering systems, a front steering system and a rear steering system, or in a combined steering. In this way, a four-runner steered vehicle, typically having separate steering systems at the front and the rear is provided. The inventive vehicle typically being a sleigh is particularly useful for slalom running on a snow or ice surface.

According to an embodiment of the present invention, the front steering system is attached to the steering wheel, typically being part of the former and the rear steering system is attached to the seat, and trigger by the latter, which can be tilted to steer. In this way, both the steering wheel and the seat can assist each other and be independently controlled by a user to steer the sleigh.

According to another embodiment of the present invention, the front steering system comprises steering gear conFIG.d to operate according to Ackermann principle and the front runners are attached to stages at an angle to the frame such that they provide carving of inner-edges during turning. Typically, the stages are directed backwards. In this way, steering is even further improved compared to prior art sleighs having only one runner provided for steering.

According to another embodiment of the present invention, the vehicle further comprises a plough-brake device arranged to and triggered by the front runners. In this way, braking efficiency is much improved by using plough-braking in relation to conventional brakes for sleighs not using the runners for braking.

Further advantages and features of embodiments of the present invention will become apparent when reading the following detailed description in conjunction with the drawings.

Short description of the drawing FIG.s

FIG.1 shows a view in perspective from above of a vehicle in the form of a sleigh according to an embodiment of the present invention,

FIG. 2 shows the same sleigh as shown in FIG. 1 from below,

FIG. 3 shows the same sleigh as shown in FIG. 1 and 2 from above, having the runners positioned for turning to the left,

FIG. 4 shows the same sleigh as shown in FIG. 3, positioned having the runners positioned for turning to the left, from the rear side,

FIG. 5 shows a side-view of a sleigh having a brake according to an embodiment of the present invention,

FIG. 6 shows the same sleigh as shown in FIG. 5 in a view from above showing the position of the runners during braking, and FIG. 7 shows a side-view of a sleigh having a brake according to another embodiment of the present invention.

Detailed description of embodiments of the invention

FIG. 1 shows a view in perspective from above of a vehicle, herein a sleigh, 1 according to an embodiment of the present invention. The sleigh 1 comprises a frame 2 provided with a seat 3 thereon, a steering wheel 4 provided in a front part of the frame 2, and four runners, 5a-d attached to the frame 2. The four runners 5a-d are arranged in two separate steering systems, a front steering system 5', including a pair of front runners 5a, b and a rear steering system 5 ", including a pair of rear runners 5c, d.

The sleigh 1 shown in FIG. 1 is only a non-limiting embodiment of the present invention. For instance, the number of runners can be three instead of four, one frontal runner being part of the front steering system and the two rear runners being part of the rear steering system. Furthermore, according to yet another alternative embodiment of the present invention (not shown) only the rear runners can be arranged to steer. The front and rear steering system can also alternatively, without departing from the invention, be combined into one common steering system. Herein, the term "front" including "frontal" is meant to be the part of the sleigh 1 normally being first in a direction forward during use.

The runners can be embodied as skis adapted for use on a snow or ice surface, but can also be adapted to any other surface such as a surface without snow or ice, including a road surface. The runners can then comprise wheels, similar to car wheels, or two-wheeled boggies for instance.

Now is referred back to FIG. 1 and the embodiment of the invention shown there.

The frame 2 typically being made of galvanised steel, or aluminium, tubing comprises an elongate straight tubing 2a, typically having a larger diameter than the rest of the tubing. Attached thereto, there are provided two essentially u-shaped front legs 2b on each side thereof and two u shaped rear legs 2c slightly bent downwards (seen in a normal position during use) onto which the seat 3 is attached by fastening means 2d such as bolts such that a sleigh 1 is provided. The diameter and thickness of the tubing is typically from 15-25 mm diameter and up to 2 mm wall thickness, but may vary depending on load and stiffness requirements.

Typically, but not limited to, the frame 2 is made of separate pieces of tubing which can be partly inserted into each other and secured to provide a frame 2 made of tubing, for instance to ease transportation before assembly in flat cartoon packages. Some joints can also be welded or riveted together.

The seat 3 is typically made of polymer material such as plastics, including foamed plastics, or board covered with foam and plastics. The shape and size of the seat 3 can be any suitable for a sleigh carrying a child, a grown up person or even two persons.

Typically, the seat 3 is attached to the frame 2 by means of suitable fastening means such as bolts, or screws, in a front end of the seat and having suitable flexibility such that it can return to its original position. The seat 3 can also be attached to the frame in another way, provided rear runner steering can be provided, without departing from the invention.

The steering wheel 4 and the runners 5a-d can be made of plastics or any other suitable material, provided requirements regarding stiffness, temperature and wear resistance etc can be fulfilled. The material, design and dimensions typically depend on type of surface to be run.

The steering wheel 4,typically inclined towards a user, is typically provided to a steering gear 4a comprising steering column 4b into which a steering axle 4c runs. The steering axle 4c is attached to the steering wheel 4 in one end 4c' thereof and attached to tie rods 4d by means of a steering plate 4e. The tie rods 4d are connected to a respective runner 5a, b by means of a respective front steering link 4f, g such that the runners 5a, b typically can be steered according to the Ackermann principle by means of the steering wheel 4. The Ackermann principle implies that an inner runner turns slightly more an outer runner when turning to compensate for slipping of the runners when turning. Since this principle is well known for the person skilled in vehicle design it will not be further described herein this disclosure. A vehicle without Ackermann steering is also possible.

The front runners 5a, b are typically attached to the frame by means of stags 6 inclined backwards (seen in a normal driving direction N) such that they can pivot up and down slightly to be able to follow uneven ground also at high speeds. Since the stags 6 are inclined, the runners 5 a, b will be tilted during turning which implies that the inner edges (in a turn) of the runners 5a, b will be pressed down into the ground providing better tracking. The stags 6 are attached to the frame 2, typically by fastening means such as rivets and to the steering links 4f, g. The stags 6 and the front left and right steering links 4f, g can be made as an integral part or be separate parts permanently joined together.

Now is also referred to FIG. 2 showing further details of the front steering gear.

The steering links (not shown in FIG. 2 since they are hided by the runners 5a, b) are attached to the front tie rods 4d as disclosed above. The front tie rods 4d are attached to the front steering plate 4e, which is attached to the steering axle 4c. When a user turns the steering wheel 4, to steer the front runners 5a, b, the steering axle 4c turns inside the steering column 4b going through the central tubing 2a of the frame 2. The rear runners 5c, d are also attached to the frame 2 by means of stags 6 (see FIG. 1) inclined forwards (seen in the normal driving direction N), in the way as described above in relation to the front runners 5a, b, having rear steering links 4h (see FIG. 1), i being attached to rear tie rods 4i (see FIG. 2). The rear tie rods 4i are attached to a guiding plate 9 connected to a pivot able guiding part 1 1 attached to the seat 3 such that it 11 can pivot around the central tubing 2a of the frame 2 when the seat 3 pivots. In this way the rear runners 5c, d can also be steered assisting steering of the sleigh 1.

This is shown in more detail in FIG. 3, which shows the same sleigh as shown in FIG. 1 and 2 in a plan view from above, having the runners 5c, d positioned for turning to the left (seen in the normal running N) according to the Ackermann principle for improving tracking. The Ackermann principle implies that the inner front runner 5a is turned more by an angle than the outer front runner 5b which is turned by an angle a ₂ . It is also shown that the rear runners 5c, d are positioned to steer slightly against the front runners 5a, b since their steering angles are smaller than the ones for the front runners 5a, b. This improves tracking even more. FIG. 4 shows the same sleigh as shown in FIG. 3, having the runners 5a-d positioned for turning to the left, from the rear side. It is clearly shown how the runners 5a-d are positioned in relation to each other as disclosed above. The seat 3 is tilted since the rear runners 5c, d are positioned for turning to the left. Now is referred to FIG. 5, which shows a side-view of a sleigh 1 having a brake according to an embodiment of the present invention, and to FIG. 6, which shows the same sleigh as shown in FIG. 5 in a view from above showing the position of the rear runners 5c, d during braking. The sleigh 1 comprises a brake device 12 arranged to trigger the rear runners 5 c, d to be positioned inwards (inwards seen in relation to the normal running direction N) when braking such that plough-braking is provided. The brake device 12 comprises a brake trigger link, or some other means (not shown) arranged to pull the guiding plate (cf. FIG. 2) forwards to pull the steering links 4h forwards and inwards by means of the tie rods 4i (seen in relation to the normal running direction N).

The brake trigger link can be attached to a brake handle, or a brake pedal.

Now is referred to FIG. 7, which shows a view in perspective from below of a sleigh 1 having a brake device 12 according to an alternative embodiment of the present invention.

According to another alternative embodiment of the present invention, the frontal runners 5a, b can comprise a brake device 12. The brake device 12 has a plough-shaped profile arranged at a rear part 5a ^' of said at least one front runner 5a, b such that a user can press the brake device against the surface by means of his/her foot. The plough brake 12 is similar to old-fashioned snow ploughs, wherein a central line splits the snow and transports the snow outwards. In this way, the brake will not be clogged with snow, which will otherwise impair its function. The plough-shape brake 12 can be made of the same material as the runner and integrated with the same, but can also be made separate of the same or another material and fastened by means of conventional fastening means such as screws. In this particular embodiment, the runner(s) having the brake 12 is/are typically made of more elastic plastics than the other components, because the user presses the rear part(s) down using his/her heel.

By means of the plough-brake 12, braking efficiency is much improved compared to conventional technology by using plough-braking in relation to conventional brakes for sleighs not using the runners for braking. Also, the design of the brake is much simplified compared to convention mechanical brake mechanism requiring a plurality of mechanical links and other brake components, which can be complicated and expensive to

manufacture. The embodiment of the invention shown in FIG. 7 also has slightly different steering gears. The frontal steering gear includes frontal steering links 4g, f, which can be ball- joints attached to front tie rods 4d that are adjustable in length as shown. The front tie rods 4d are attached to the front steering plate 4e, which is attached to the steering axle 4c. Also the rear steering links 4h can be ball-joints attached rear tie rods 4i adjustable in length.

Also other shapes of the brakes such as a plurality of extending pins instead are possible without departing from the invention.

According to an alternative embodiment of the present invention (not shown) the vehicle has three runners of which the rear runners, d are arranged to provide steering on a surface. The frontal runner can be arranged without steering in the same way as a conventional bob sleigh. According to yet another alternative embodiment of the present invention (not shown), the steering wheel can be arranged such that the rear runners 5c, d can be steered by means of the steering wheel instead of the seat. The present invention is not limited to the above-described preferred embodiments.

Various alternatives, modifications and equivalents may be used. Therefore, the above embodiments should not be taken as limiting the scope of the invention, which is defined by the appending claims.