GB2568652A - Motorised sledge - Google Patents

Abstract

A convertible motorised snow vehicle e.g. sledge having a traction belt 4, a pair of parallel skis 1a/b that are pivotally mounted to the exterior of the sledge’s, allowing the skis to move from a stored to a deployed position and a steerable ski 1c. When the parallel skis are in the stored position, perpendicular to the longitudinal axis of the sledge (fig 3b), the traction belt engages with the snow/ice allowing the sledge to be used as a snowmobile, and carry one or more persons up a snow or ice covered slope/hill. When the parallel skis are pivotally rotated by 90 degrees to a deployed position (fig 3a), and engage with the snow/ice, the traction belt is lifted thereby allowing the sledge to be slide down a snow or ice covered slope/hill. Preferably the parallel skis are mounted to hinges 23, wherein the user may manually move the skis and preferably lock the hinges in position. Alternatively the skis are held and moved into position by motors. Preferably the parallel skis have a curved profile along their longitudinal axis to facilitate the rotation of the skis

Description

This invention relates to a dual sledge and snowmobile. Sledging is an easy activity enjoyed by many children and adults in snowy environments. However, when sledging, it is necessary to walk up the hill with the sledge, which requires significant effort and time, only to sledge down the hill in a relatively short time. What is known already is fixed route ski lifts, however they require a modest utilisation fee and are only available in certain locations such as ski resorts, where sledgers may then have to share the piste with skiers, compromising safety and enjoyment. Hence most sledging takes place in public parks or in quiet villages, where ski lifts are not present.

Snow vehicles also exist, known as snowmobiles, however they are bulky, very expensive and not suitable for children. They also require regular maintenance and by design, do not actually allow for sledging to occur as the high friction drive belt is always engaged with the snow.

Hence the invention described below aims to solve the problems stated above.

Devices have previously been proposed such as Seiler (US 3814918), Steele (US 1916643), Gonzalez (WO 2009087256) and Schmidt (DE 2003326), but these are not totally successful in achieving the said aim.

Seiler (US 3814918) discloses a motorised snow bicycle, however like Steele (US 1916643) it comprises of a single rear cleated drive wheel which will not have sufficient traction to climb significant snow-covered hills. The drive mechanism of Seiler is also not retractable, and so once the user wishes to sledge down the hill, this is greatly hampered by the high friction produced from the drive wheel that is connected to the motor rubbing against the snow during descent.

Gonzalez (WO 2009087256) and Schmidt (DE 2003326) both have retractable traction belts in order to lift the high friction belt from the snow surface, giving the potential to sledge down the hill as only the smooth skis are in contact with the snow. However the first problem with their design is that when the traction belt is moved up and down, the distance between the motor and the drive sprocket changes, hence tension in the chain is not maintained. This leads to less power and makes belt retraction unreliable and fiddly as the user must ensure the sprocket reengages with the chain upon lowering of the belt. Furthermore, when the traction belt is lowered to drive the sledge, it is merely just touching the surface of the snow, so the user's weight is distributed between the three skis and the belt itself. Therefore the amount of traction produced by the belt, and consequently the amount of power transmitted to the ground, is greatly reduced. Climbing of hills therefore becomes slow or in cases where the hill is steep, not possible. Schmidt also requires the use of small wing nuts to raise or lower the traction belt, which is undesirable for the user since thick waterproof gloves are usually worn when sledging outdoors, resulting in restricted finger movements.

Statement of Invention

The aim of this invention is to solve the problems above and allow a user to ascend up a hill, by means of a traction belt and motor, and then sledge down the hill without the traction belt being in contact with the snow. This is achieved by having the two parallel side skis hinged to the body of the sledge using lockable lever hinges. Thus when ascending, the skis are rotated outwards and locked in place, leaving only the belt resting on the surface of the snow to be driven by the motor. Once the user wishes to sledge, the skis are rotated inwards and locked in place, lifting the belt from the snow and leaving only the skis touching the snow. Thus high speed sledging is possible. This invention can also be used as a snowmobile for general cruising, if the skis are kept in the outward hinged position.

Advantages

This invention allows users of all ages to ascend hills quickly, in an affordable, relaxing and easy manner where no prior experience or physical strength is required. Users can then sledge down the hill at unrestricted speeds, maximising their enjoyment. Since hills can now be ascended effortlessly and quickly, users can now complete a greater number of sledge runs in a given period of time. This invention can also be regarded as an affordable 2 in 1 sledge and snowmobile, with the option to continually use one mode if desired. Thus the invention can provide a very affordable and easy to use, smaller and less bulky snowmobile, with sufficient power for most recreational users.

Brief Description of the Drawings

The invention will now be described solely by way of example, with reference to the accompanying drawings in which:

Figure 1 is a perspective view of the motorised sledge according to the present invention Figure 2 is a top view of the motorised sledge of Figure 1

Figure 3a is a front view of the device with the skis rotated inwards and locked, lifting the traction belt off the snow. This format transforms the device into functioning as a sledge. Figure 3b is a front view of the device with the skis rotated outwards and locked, placing only the traction belt on the surface of the snow. This format transforms the device into functioning as a snowmobile.

Figure 4 is a side view of the device with the skis rotated inwards and the belt raised off the snow as in Figure 3a

Figure 5 is a top front view of profiled skis used on the device according to a variant of the embodiment

Detailed Description of the Embodiments

In the first embodiment, with particular reference to Figures 1 and 2, a high friction traction belt 4 consisting of flaps 5 and spikes 6, is stretched around four belt sprockets 7 placed on shafts 8a and 8b. Shafts 8a and 8b are attached to a support structure using pillow block bearings 9. Bearings 9 are attached to beams 10, which in turn are attached to beams 11 which are attached to the main frame 12, thus connecting the traction belt 4 to the main frame of the device 12. A chain sprocket 13 is attached to shaft 8a, where a drive chain 14 is permanently looped between 13, a tensioner and the drive sprocket of motor 15, which is wedged and strapped between horizontal beams 28. This allows the traction belt 4 to be driven, moving the sledge forward. Due to the high power of motor 15 and high friction of belt 4 there is sufficient traction to climb hills when belt 4 is in contact with the snow. Furthermore due to the distance between motor 15 and sprocket 13 always being constant, regardless of whether or not belt 4 is in contact with the snow, tension in chain 14 is always maintained so reliability and power transmission is greatly increased.

The sledge itself fundamentally consists of main skis la and lb and a front steerable ski lc. lc is rotated by handlebar 16 allowing the sledge to always be steered whether skis la and lb are rotated inwards or outwards. Pole 25 is attached and pivoted to front ski lc about 21, and slides within tube 12. In-between two stopper discs 27, a compression spring 26 is placed, which applies a downwards pressure to tube 25 and ski lc. This means that the height of ski lc is automatically adjusted, as the device is raised or lowered from the ground, ensuring chair 20 remains level, and that ski lc is touching the snow at all times which is vital for reliable steering and use on rough terrain. Spring 26 also acts as a conventional suspension for the device during use. A metal pin attached to 25 extrudes slightly from slot 29, which is cut out of tube 12, ensuring that rotation of ski lc by the handlebar is still possible as is free vertical movement of ski lc. It also ensures that during transportation ski lc remains attached to frame 12 and does not slide out. On handlebar 16 is a brake lever 17, which is connected to a spiked paddle 18 via a cable running through tube 12, which then digs into the snow as lever 17 is pressed, braking the sledge. Also on handlebar 16 is a twist grip throttle controlling the speed of motor 15 and thus the speed of the sledge. Motor 15 is powered via battery pack 19. Connected to the main frame 12 is an ergonomic seat 20 for the user to sit on.

Skis la and lb are each attached to two lever locking hinges 23 via beams 22. Hinge 23 is a high torque lever locking hinge, consisting of a locking lever 24, which is large so that it can be easily manipulated even when wearing ski gloves. Hinge 23 can be freely rotated when lever 24 is rotated anticlockwise, allowing the beams 22 and skis la and lb to also be freely rotated. Once the desired position of the ski is selected, the lever is rotated clockwise and the hinge is locked. The hinge can no longer be rotated, even when the skis are subjected to lateral forces, due to the high torque of the hinges. Beams 22 are of a suitable length to maximise stability and practicality. The length of beam 22 is long enough to successfully lift traction belt 4 off the snow, as shown in Figure 3a, but is not too long so as to maintain a low centre of gravity for increased stability. Additionally, keeping beams 22 as short as possible is beneficial in order to decrease the moment about hinge 23 and increase the permitted magnitude of the lateral forces on skis la and lb.

Now with particular reference to Figures 3a and 3b, due to hinges 23 and beams 22, it is possible to rotate the skis through ninety degrees so that they are either above (Figure 3b) or below (Figure 3a) belt 4. This then provides the ability to quickly and easily switch between having the belt being in contact with the snow, hereinafter known as snowmobile mode, which allows the device to cruise or climb up a hill using motor power; or having the belt completely off the snow leaving the device sliding on frictionless skis, hereinafter known as sledge mode, in order to sledge down a hill.

Due to the simplicity of the invention, little weight is added to the sledge other than the drive mechanism and power source, both of which are required for any electric vehicle. This lightweight design, coupled with the fact that when in snowmobile mode the vast majority of the user's weight is transmitted through belt 4, which has a very high friction surface designed to grip the snow, means that there is a lot of traction and power to propel the device and its rider forward, even up steep gradients.

In the second embodiment, with particular reference to Figure 2, beams 10 and 11 are removed and bearings 9 are attached directly to frame 12. This means that the width of belt 4 is maximised as it can extend to the edge of the frame as very little space is wasted. The width of belt 4 will be approximately equal to the width of the sledge, thus maximising the surface area of the traction belt and hence be able to climb steeper hills at greater speeds. This is possible only due to the way in which skis la and lb are attached to the sledge. Rather than the centre of the ski being on the centre of the frame, leaving half of the ski intruding into the area in which belt 4 is located, as is the case with conventional sledges, with this invention the skis lie below the belt when in snowmobile mode, and to the sides when in sledge mode, hence the skis never intrude into the volume of space in which the widened belt operates or is positioned.

In the third embodiment, with reference to Figure 5, skis la and lb are replaced with curved profile skis 31a and 31b respectively. A curvature is created on the inner edge of the skis to facilitate transformation between snowmobile and sledge mode. Now instead of lifting one side of the sledge, then rotating one ski, then repeating with the other side, the skis can more easily be rotated without the need to lift the sledge, as the curvature of the skis enables the sledge to self-lift and self-drop as the ski comes into contact with the ground. Since heavy lifting of the sledge is no longer required, even young children can utilise this invention independently.

In the fourth embodiment, with reference to Figures 1 and 2, only one lever locking hinge,

23, is required per ski (la and lb), rather than two. In this embodiment, for each ski, hinge 23 is replaced by a slightly larger but greater torque hinge, and the other is just a regular hinge. This means only two levers need to be un/locked to switch between snowmobile and sledge mode rather than four, as was the case in the first embodiment. This further shortens the time it takes to switch between modes.

In the fifth embodiment, with reference to Figures 1 and 5, when coupled with skis 31a and 31b as in the third embodiment, hinges 23 may be replaced with geared stepper motors or the like. This will allow the skis to automatically rotate into the desired position due to the self-raising nature of skis 31a and 31b, initiated by a button located on the twist grip throttle found on handlebar 16. Since the stepper motors are geared and have a high torque, when supplied with no power the shaft can't be moved, so skis 31a and 31b are locked into position, just as they would be if hinges 23 were locked into position using levers

24.

The materials and dimensions of the device conceived so far may vary, and further alternative embodiments may be envisaged, which nevertheless fall within the scope of the following claims.

Claims (12)

1. A snow vehicle for carrying one or more persons uphill on snow, ice, or any similar slippery surface and then sliding downhill with minimal friction, comprising a main frame, onto which are attached a traction belt driven by a motor unit, an energy source, a steerable ski connected to a handlebar, and main skis which can be rotated outwards.

2. A motorised sledge according to claim 1 further comprising a brake mechanism.

3. A motorised sledge according to claim 1 where said steering ski can pivot and/or can freely extend in length.

4. A motorised sledge according to claim 1 where the main skis are attached to the frame and rotate using lever locking hinge(s) and thus can be locked into position so that said skis either lie below the traction belt, allowing the vehicle to function as a sledge, or are rotated and locked to the side of the traction belt, allowing the vehicle to operate as a self-propelling snowmobile with the ability to ascend hills.

5. A motorised sledge according to claim 1 whereby the main skis can rotate outwards using ordinary hinge(s) and then be held into position by a locking mechanism.

6. A motorised sledge according to claim 1 whereby the main skis can rotate outwards using torque hinge(s).

7. A motorised sledge according to claim 1 where said main skis can be rotated and held into position using motors and be electronically controlled.

8. A motorised sledge according to claim 1 where said main skis have a curved inner edge, curved outer edge, or both inner and outer edges curved, to facilitate rotation of said skis.

9. A motorised sledge according to claim 1 whereby only the traction belt and steering ski are in contact with the snow when moving uphill.

10. A motorised sledge according to claim 1 whereby only the main skis and steering ski are in contact with the snow when sliding downhill.

11. A motorised sledge according to claim 1 where the width of the traction belt can be maximised to a size equal to the width of the frame, this being possible due to the ability of the skis to be rotated outwards.

12. A motorised sledge according to claim 1 where said motor, traction belt, and corresponding sprockets are on fixed positions on the frame, resulting in a constant drive chain tension, regardless of whether or not the traction belt is in contact with the snow.