SKATEBOARD WITH A DEFECTIVE FOOTBOARD TO POWER THE WHEELS

Description

Technical field

[0001] The invention relates to a skateboard with an elastically deformable footboard, on the underside of which two skateboard axles are arranged spaced apart from each other in the longitudinal direction of the footboard and oriented transversely to the longitudinal direction for the attachment of two wheels each. State of the art

[0002] Patent DE 103 27 970 A1 discloses a skateboard featuring an elastically deformable deck. Two skateboard axles are mounted on the underside of the deck, with wheels rotatably attached to the rear axle of the skateboard via a freewheel with a planetary gear system. The one-piece deck is curved upwards when unloaded and is capable of oscillating through an angle α when weight is periodically loaded and unloaded. These oscillations result in a periodic pendulum motion of the skateboard's rear axle, allowing the freewheel to be accelerated to such an extent that the output speed in the planetary gear system exceeds the rotational speed of the drive wheels.

[0003] The publication DE 34 27 834 A1 discloses a rolling board with a tiltable footboard, the periodic tilting movements of which are used by means of a chain drive to drive a drive wheel, the drive axle of which is coupled to the chain drive via a freewheel.

[0004] Publication GB 2 452 692 A discloses a skateboard that incorporates a cable stretched between the front and rear axles, connected to a rack and pinion drive mounted on the rear axle. Deformation of the board alters the distance between the front and rear axles, thereby transmitting torque generated in the drive mechanism to the rear wheels. When the board is unloaded, a tension spring attached to the rack and pinion drive retracts a linearly deflected rack, keeping the cable taut at all times.

[0005] Document US 2002 / 0067018 A1 discloses a scooter with an upward-curved footboard. Applying pressure to the footboard increases the distance between the front and rear wheels, thus accelerating the scooter. A freewheel mechanism on the rear axle prevents the rear wheel from rolling backward when the upward-curved footboard is pressed down, thereby generating propulsion, similar to the movement of a caterpillar track, through pushing off in the direction of travel.

[0006] Document US 8,820,763 B2 describes a type of kick scooter in which the distance between the front and rear axles is kept constant by a rigid connecting element. A convex footboard is positioned above this connecting element, so that when the convex footboard is pressed down, a rack attached to its rear end is actuated by a gear drive mounted on the rear axle, which in turn drives the rear wheel.

[0007] Document WO 2014 / 043450 A1 describes a kick scooter similar to the one described above, featuring an upwardly curved footboard and a rigid connecting element between the front and rear axles. However, in this scooter, the forward and backward movement of the rear end of the footboard is converted into a rotational movement to drive the rear wheels via a mechanism. This mechanism involves a connecting element attached to the rear end of the footboard, which is guided along a spiral component. The axis of this spiral is connected to the rear axle of the vehicle. The rotational speed of the rear axle can be influenced by the number of turns or by tilting the spiral longitudinally.

[0008] In all known mechanically driven skateboards powered by muscle force or weight shifting, a weight-driven deformation or change in the inclination of the footboard is used directly to propel the skateboard via a drive mechanism.

[0009] German patent application DE 10 2004 029 227 A1 discloses a trolley for moving a person using their own physical strength. The trolley has a frame with a front section (4) and a rear section, each of which is mounted on at least one roller, at least one of which is a drive roller. A hand-operated control element is arranged in the front section of the frame, onto which force can be exerted by a user. A drive device, actuated by the user's force on the hand-operated control element, is also provided, which transmits the force exerted on the hand-operated control element to the drive roller in the rear section of the frame. Description of the invention

[0010] The invention is based on the objective of further developing a skateboard with an elastically deformable deck, on the underside of which two skateboard axles, spaced apart from each other in the longitudinal direction of the deck and oriented transversely to the longitudinal direction, are attached for mounting two wheels each, in such a way that a muscle-powered skateboard drive ensures that skateboard acceleration is generated not, as with all known drive systems, during a deformation or change in position of the deck caused by body weight, but during the unloading of the deck. In this way, the skateboard can be accelerated and operated by a user in a natural and much more harmonious manner.

[0011] The solution to the problem underlying the invention is specified in claim 1. Advantageously developing features of the invention are set out in the dependent claims and the further description, in particular with reference to an illustrated embodiment.

[0012] The skateboard according to the solution has at least one skateboard axle, preferably the rear axle, which has a preferably continuous pivot shaft to which the wheels are attached at the ends of the pivot shaft in a rotationally fixed manner. In addition, a transmission, preferably in the form of a freewheel transmission or a centrifugal clutch, is mounted along the pivot shaft, which is capable of generating a drive torque oriented exclusively in one direction of rotation around the pivot shaft.

[0013] Furthermore, a connecting element extending between the skateboard axles is attached to the underside of the deck. This connecting element is preferably flexible and has two connecting element ends that are attached to the skateboard axles and / or the deck, preferably as close as possible to the skateboard axles. The connecting element extends between its connecting element ends at a distance from the underside of the deck, having a convex shape facing away from the deck. It has a maximum distance from the deck midway between the two skateboard axles, which is maximal when the deck is unloaded and can be reduced by means of load-induced elastic deformation of the deck.

[0014] Furthermore, a drive element transmitting tensile forces, shaped like a rope or band, is provided, which on the one hand is attached to the gearbox in such a way as to be wound and unwound according to a first winding direction of rotation and on the other hand is articulated in the area of ​​the maximum distance between the footboard and the connecting element in such a way that when the footboard is loaded and the maximum distance between the footboard and the connecting element is reduced accordingly, the drive element shaped like a rope or band can be wound onto the gearbox and when the load on the footboard is reduced and the maximum distance between the footboard and the connecting element is increased accordingly, the drive element can be unwound by exerting the drive torque acting on the rotating shaft, which is caused at least by an elastic restoring force inherent in the footboard.

[0015] To accomplish the winding of the rope- or band-shaped drive element onto the gearbox during a load on the footboard and a related reduction in the distance between the footboard and the connecting element, a tensile force-transmitting, rope- or band-shaped winding element is provided, which is attached to the gearbox in a winding direction opposite to the first winding direction and is attached to a spring arrangement to generate a tensile stress acting along the winding element.The spring force of the spring arrangement and the resulting tensile stress along the winding means should be chosen to be as low as possible, especially since it continuously counteracts the drive torque acting during the acceleration phase of the footboard, but should be sufficiently large to ensure controlled winding of the rope- or tape-shaped drive means onto the gearbox, preferably in the state of maximum weight-induced elastic deformation of the footboard, where the maximum distance between the footboard and the connecting element is minimal.

[0016] In order to optimize the acceleration of the skateboard within the acceleration phase, i.e. during the elastic reshaping of the footboard from the state of maximum weight-force-induced deformation, in which the footboard has a maximum approximation to the connecting element, to the load-free footboard state, it is necessary to realize a multiple wrapping of the rope- or band-shaped drive element around the gearbox.For this purpose, the skateboard provides for the attachment of at least one, preferably a multitude of, rotatably mounted guide pulleys, both on the underside of the deck and on the side of the connecting element facing the deck at the point of maximum distance between the deck and the connecting element. This allows the drive element, attached at its end to the deck or the connecting element at the point of maximum distance, to be guided by multiple wraps around the rotatably arranged guide pulleys, similar to a multiple pulley system, before being wound directly or indirectly onto the gearbox. In this way, the length of the drive element that can be wound onto the gearbox can be significantly increased relative to the maximum stroke or maximum change in distance between the deck and the connecting element.

[0017] The skateboard, as designed, is thus able to convert the bending stress temporarily stored in the deckboard, which originates from the weight of a person standing on the skateboard, into drive energy when the bending stress is released or lifted. The rope- or band-shaped drive element is guided several times between the deckboard and the connecting element located underneath it via rotatably arranged pulleys. During the phase of the deckboard being compressed, and the resulting small gap between the deckboard and the connecting element, the drive element winds onto the gearbox on the rear skateboard axle. During the rocking or lifting phase...Relieving the load on the running board causes the bending stress to return it to its unloaded starting position. This increases the distance between the pulleys attached to the running board and the connecting element, allowing the drive element wound or coiled on the gearbox to unwind. This, in turn, drives the rear axle's pivot shaft and the wheels attached to it.

[0018] Because the drive element is guided several times over the pulleys on the footboard and the connecting element, the path of the drive element can be influenced via this mechanism in the manner of a pulley system, so that the power transmission can be adapted to different rotational speeds of the rotating shaft on the rear skateboard axle.

[0019] Preferably, a stretch-resistant rope or tape made of a low-wear plastic fiber braid or a metallic material is suitable for forming the winding and winding device. Brief description of the invention

[0020] The invention is described below by way of example, without limiting the general concept of the invention, with reference to the drawings. The drawings show: Fig. 1a Overall side view of a skateboard designed according to the solution in the unloaded state, Fig. 1b Detail view of the skateboard in the unloaded state, Fig. 2a Overall side view of a skateboard designed according to the solution in the loaded state and Fig. 2b Detail view of the skateboard in the loaded state. Ways to implement the invention, industrial applicability

[0021] This applies to all Figures 1a, b as well as 2 a, bThe illustrated skateboard consists of a flexible or elastically deformable deck 1, preferably made of glued wood or other suitable flexible materials. The deck 1 has a typically skateboard-shaped form and is preferably slightly convex in the middle of the deck area and has a positive camber, as is known in skateboards.

[0022] The Figures 1 a , b show the skateboard in a full side view and detail view in the unloaded state, which Figures 2a, b The skateboard is shown in its respective weighted state. The subsequent description refers to all figures.

[0023] On the underside of the footboard 1 are attached a front and rear skateboard axle 2, 3, to which two wheels 4 are attached.

[0024] The skateboard front axle 2 corresponds to the common design of a skateboard axle, which causes the skateboard to steer when the footboard 1 is tilted laterally.

[0025] Below the footboard 1, a connecting element 5 is attached to the underside of the footboard 1 between the skateboard's front and rear axles 2, 3. The connecting element 5 can be a single piece or composed of at least two parts joined together by a stable and preferably rigid joining element. In the case of a connecting element 5 composed of two parts, it is advantageous to select the joint centrally along the longitudinal extent of the connecting element 5. The connecting element 5 is not necessarily made of a flexible material, e.g., wood or fiber-reinforced plastic. It is also conceivable to design the connecting element 5 to be dimensionally stable, e.g., by appropriate choice of shape and / or material.

[0026] The two ends of the connecting element 5 are preferably fastened via hinges or grooves, allowing for relative longitudinal movement of the connecting element 5 relative to the footboard 1. Furthermore, the convex shape of the connecting element 5 is chosen such that, in the area of ​​the maximum distance 6 between the connecting element 5 and the footboard 1, the connecting element 5 just barely does not touch the ground on which the skateboard rests.

[0027] On the underside of the footboard 1 and also on the top side of the connecting element 5, a bearing 7, 8 is arranged centrally and transversely to the longitudinal direction of the footboard 1. Several ball-bearing mounted pulleys 9, 10 are mounted in each bearing, over which a rope-like drive element 11 is guided. The rope-like drive element 11 is attached at one end, either to the footboard 1 or to the connecting element 5, and runs around the multiple pulleys 9, 10, which are rotatably mounted on the bearings 7, 8, and then over a further pulley 12 located near the rear skateboard axle 3. The rear pulley 12 prevents the distance between the rear pulley 12 and the bearings 7, 8 from increasing when the footboard 1 is pressed down and the skateboard rear axle 3 tilts as a result.The rear deflection pulley 12 is also mounted so that it can tilt laterally, so that the rope-like drive element 11 cannot jump out of the deflection pulley guide during steering movements of the rear skateboard axle 3.

[0028] The board-like connecting element 5 has a recess in the area of ​​the rear guide pulleys 12, through which the rope-like drive element 11 can be guided unhindered towards the rear skateboard axle 3. The rear skateboard axle 3 differs from a standard skateboard axle in that it has a continuous pivot shaft (not shown) on which the wheels 4 are mounted in a rotationally fixed manner. The pivot shaft of the rear skateboard axle 3 is connected to the axle frame 13 via ball bearings. The axle frame 13 is partially open, allowing a gearbox 14, preferably in the form of a freewheel gearbox or a centrifugal clutch, to be mounted directly on the pivot shaft. The rope-like drive element 11 is attached to the end of this gearbox so that it can be wound and unwound in a first direction of rotation.For this purpose, the gearbox 14 has a first groove-shaped spindle contour 15 for the winding and unwinding of the rope-shaped drive element 11.

[0029] Furthermore, the rear skateboard axle 3 is attached in the usual way for skateboard axles, so that a lateral tilt of the footboard 1 causes the skateboard to steer.

[0030] Thus, the rope-shaped drive element 11 extends between a fixed attachment on the footboard 1 or connecting element 5 in the area of ​​their mutual maximum distance 6 and the gearbox 14 attached to the rear skateboard axle 3.

[0031] To ensure that the rope-shaped drive element 11 is wound securely and in a controlled manner onto the first spindle contour 15 arranged on the gearbox 14 when the skateboard is under load, especially since the maximum distance 6 between the footboard 1 and the connecting element 5 is minimal in this state (see Figures 2a, b), the gearbox 14 provides a second groove-shaped spindle contour 16 on which a rope-shaped winding element 17 is wound and fixed, with a second winding direction oriented opposite to the first. The other end of the winding element 17 is fixed to a spring assembly 18, which is preferably attached centrally to the underside of the footboard 1.

[0032] The spring arrangement 18 generates a tensile force or tension acting along the rope-shaped winding means 17, which is designed to be just strong enough to wind the loose rope-shaped drive means 11 onto the first spindle contour 15 on the gearbox 14, especially since, as will be explained further below, it counteracts the drive torque.

[0033] The gearbox 14 is arranged and designed such that, when the rope-shaped drive element 11 is wound up, it can move freely in the opposite direction of travel without affecting the rotation of the drive shaft to which the wheels 4 are fixedly attached. Conversely, when the rope-shaped drive element 11 is unwound, a torque accelerating the skateboard is transmitted to the drive shaft as long as the unwinding occurs faster than the rotation of the rear axle's drive shaft.

[0034] The winding and unwinding process of the rope-shaped drive element 11 onto and from the first spindle contour 15 is explained below.

[0035] The Figures 1a, b Figure 1 shows the skateboard in a load-free state, in which the deck 1 and the connecting element 11 located beneath the deck 1 are at their maximum distance from each other. In a first phase, a rider steps onto the skateboard and pushes the elastic deck 1 downwards. This reduces the distance between the deck 1 and the connecting element 5, and the rope-like winding element 17 winds the now freed, or loose, rope-like drive element 11 onto the first spindle contour 15 of the gearbox 14. This state is shown in the Figures 2a, b illustrated. The winding process of the rope-shaped drive element 11 does not impair the forward movement of the skateboard.

[0036] As soon as the rider pushes off upwards and relieves the pressure on the footboard 1, the footboard 1 returns to its original shape on its own due to the inherent elastic restoring forces. This load-free state is described in the Figures 1a, b The maximum distance 6 between the footboard 1 and the connecting element 5 increases, causing a tensile force along the rope-shaped drive element 11, which initiates the unwinding of the rope-shaped drive element 11 from the first spindle contour 15 on the gearbox 14. The elastic restoring forces released in the footboard 1 are converted by means of the rope-shaped drive element 11 into a torque that acts on the rotating shaft of the rear skateboard axle 3, accelerating the movement, as long as the rotational speed of the gearbox 14 is greater than the rotational speed of the rotating shaft during the unwinding of the rope-shaped drive element 11 from the first spindle contour 15. Reference symbol list

[0037] 1 Footboard 2 Front skateboard axle 3 Rear skateboard axle 4 Wheels 5 Connecting element 6 Maximum spacing 7, 8 Bearings 9, 10 Pulleys 11 Cable drive 12 Rear pulleys 13 Axle frame 14 Freewheel gear 15 First spindle contour 16 Second spindle contour 17 Cable winding device 18 Spring assembly

Claims

1. A skateboard having an elastically deformable deck (1), on the underside of which two skateboard axles (2, 3) are mounted, which are arranged spaced apart from one another in the longitudinal direction of the deck (1) and which are orientated transversely with respect to the longitudinal direction for mounting two wheels (4) in each case, wherein one of the skateboard axles (3) has a rotary shaft to which both wheels (4) are connected in a rotationally fixed manner and along which a gear is mounted which is capable of exerting, onto the rotary shaft, a driving torque orientated exclusively in one direction of rotation about the rotary shaft, and on the underside of the deck (1), a connecting element (5) is mounted which extends between the skateboard axles (2, 3), has two connecting element ends which are fastened to the skateboard axles (2, 3) and / or the deck (1) and between which the connecting element (5) is spaced apart from the underside of the deck (1), has a convex shape facing away from the deck (1), and, centrally between the two skateboard axles (2, 3), has a maximum distance (6) from the deck (1) which is maximum in a load-free state of the deck (1) and can be reduced by way of a load-induced, elastic deformation of the deck (1), characterised in that a cable- or belt-shaped drive means (11) which transmits tensile forces is articulated, on the one hand, on the gear such that it can be wound up and unwound with a first winding direction of rotation, and, on the other hand, is articulated in the region of the maximum distance (6) between the deck (1) and the connecting element (5) in such a manner that, when the deck (1) is loaded and there is an associated reduction in the maximum distance (6), the drive means (11) can be wound up onto the gear, and, when there is a reduction in the loading and an associated increase in the maximum distance (6), the drive means (11) can be unwound while exerting the driving torque which is caused at least by an elastic return force inherent in the deck (1) and acts on the rotary shaft, and in that at the location of the maximum distance (6) between the deck (1) and the connecting element (5) at least one rotatably mounted deflection roller (9, 10), over which the drive means (11) is guided, is arranged on each of the underside of the deck (1) and a side of the connecting element (5) facing the deck (1).

2. The skateboard according to claim 1, characterised in that the gear is a freewheel gear (14) or a centrifugal clutch.

3. The skateboard according to claim 1 or 2, characterised in that the connecting element (5) is elastically bendable.

4. The skateboard according to any one of claims 1 to 3, characterised in that in the load-free state, the deck (1) has a convex curvature facing away from the connecting element (5).

5. The skateboard according to any one of claims 1 to 4, characterised in that a cable- or belt-shaped winding means (17) which transmits tensile forces is joined, on the one hand, to the gear in such a manner that it can be wound up and unwound in a winding direction of rotation opposite to the first winding direction of rotation and, on the other hand, is fastened to a spring arrangement (18) for generating a tensile stress acting along the winding means (17).