WO1993017901A1 - Stair walking mechanism - Google Patents

Abstract

The invention is related to a stair walking mechanism, which is mountable to a hand driven vehicle (1) for example a handcart, wheelchair or similar transport device, which is characterised by two parallel passing elongated, primary and secondary parts (13, 17; 113, 117), optimally in the form of two telescopically movable, one inside the other, cross sectionally equal pipes or bars, of which said primary part is connected or joined to the vehicle (1) and said secondary part is equipped with a support foot (31; 131) whose lower end is constructed to make contact with a surface (34, 37) on which the vehicle rests with the goal of transportation up-or downstairs or other bilevel surface. The mechanism also has an operating device that by means of an operating pedal (12) or follower (144), is equipped in such a way as to guide the support foot up or down in relation to the vehicle, whose means (27) are equipped to guide said elongated parts to such a position to which the support foot will be found to be in an upper position.

Description

STAIR WALKING MECHANISM

The present invention relates to a special stair walking mechanism that can be mounted on to a hand driven vehicle, push¬ cart, wheelchair or other wheeled transport device.

Referring to US-A-3734 518, such a mechanism is already known, comprising a hand actuated lift mechanism coupled to a chain which is placed between two chain gears. Pulling the handle in an upwards direction causes a mechanical foot to be pushed downwards between the wheels of a handcart in order to assist the user with transport up and down a set of stairs. This mechanism is, however, very complicated in its construction and futhermore has a flaw in its practical usage as well; when walking the stairs, the mechanical foot, due to the handcart wheel size, comes extreemly close to the upper lip of the stair that is to be ascended, thus risking that the foot interfers with the lifting process.

Another type of handcart with a similar device, as mentioned above, is US-A-2834602. This mechanism also activates a mech¬ anical foot by pulling a hand lever in an upwards direction. The lever is fastened with a wire which is guided between reels in order to achieve a pully effect, thus assisting the foots movement when it raises or lowers the handcart up or down the stairs. This mechanism has, located towards the base of the foot, via a linkage, support wheels, which, when the vehicle is loaded down during transportation up or down, the linkage folds inwards towards the landing of the stair. A spring is fastened to one end of the linkage which strives to place the leading arm of this linkage in a position parallel with the horizontal plane of the handcart. This mechanism also presents the drawback of having an extremely complicated construction with many included parts. cl6385

Another previously known stair walking mechansim is shown in SE- A-8800252-2, which has a lift assembly pushing the handcart upwards one step at a time. To produce a stair climbing vehicle using this lift assembly (SE-A-8800252-2) is both complex and expensive.

Other similar mechanisms are shown in US-A-3338586, US-A- 3053546, US-A-2192396, EP-A-0056490, EP-A-0099061, EP-A-0109927 and EP-A-028757. All these mechanisms have one thing in common, the need of many parts and expensive mechanisms. These mech¬ anisms, therefore, are very complex and expensive to produce and futhermore, due to their many included parts, they are often unreliable to their function and construction.

The object of the present invention is to provide a stair walking mechanism for handcarts, wheelchairs or the like, which mechanism is so constituted, that it avoids the above mentioned drawbacks and is able to be mounted on a existing handcart, wheelchair or the like, and furthermore is easy to construct, with few parts, which are not complicated and therefore inexpensive to produce.

Another object with this invention is to produce a stair walking mechanism for a hand driven vehicle, handcart, wheelchair or the like, which, with great safety and with little risk of tipping or fastening on a stair ledge, and even with the less efforts of steering from the user, can transport the load up or down a flight of stairs.

These objects are achieved according to the invention by giving introductory part of the description of the mechanism the characterising features of claims 1 and 2.

The prefered embodiment of the invention has been given the characterising features defined in the subclaims. Another advantage with this mechanism according to the inven¬ tion, is that, due to its few and simple parts, it will be very reliable in both construction and function.

The invention is described in more detail with reference to the attached drawings, which show various proposed embodiments.

Fig. 1 is a perspective view of a handcart with the stair walking mechanism according to the invention attached thereon.

Fig. 2 is a perspective view of the mechanism.

Fig. 3 is another perspective view of the mechanism in another position.

Fig. 4 is a perspective view of the mechanism, similar to the view of fig.2, but with some parts partially or wholly removed due to clarity.

Fig. 5 is a partial cross sectional view of a portion of the mechanism, but on a larger scale.

Fig. 6 shows a partial side view of another embodiment showing the attachment of a spring to the lower end of the mechanism.

Figs. 7a - 7d show schematically how a handcart, upon which the mechanism according to the invention is mounted, is transported by hand up a flight of stairs.

Fig. 8 shows a view similar to the view of fig. 2 of another embodiment of the mechanism according to the invention. Fig. 9 shows a partial cross sectional view through the lower end of the mechanism according to the invention.

Figure 1 shows a handcart 1, by which a stair walking mechanism 2 according to the invention is mounted. The handcart 1 can be of the same type as shown in the drawings, with four vertical supports 3, of which the two outermost are extended at the top and bent in order to form two handles 4 and which at the top are attached to each- other by means of a horizontal cross member 5 and at the bottom are attached to each other by means of the loading flange 6 of the cart. A wheel shaft 7 supports two wheels 8 and is joined to the frame of the cart by means of stems 9. The mechanism 2 according to the invention, which assists by transporting the handcart up and down a stair, is, by means of fittings 10 and 11, fixed to the uppermost crossmember 5 of the handcart and the shaft 7 of the wheels 8. In fig. 1 it is evident that a control pedal 12 for the actuation of the mechanism 2 is facing the side on which the person operating this handcart will be standing.

Figures 2 - 4 show a more detailed presentation of the mech¬ anisms' 2 parts. The mechanism includes a pipe sleeve 13, which has two opposing machined slits 14 and 15 (See fig. 1) . The pipe sieve 13, which doesn't necessarily need to be rectangular in its cross section as shown, is attached to the hand cart 1 by means of fittings 10 and 11 and the lower flange fitting 16. Inside this pipe sleeve, which optimally can have the same cross sectional form as the pipe sleeve 13, whose upper end is fashioned with a opened machined slit 18 sits a reel 19 which is mounted at 20. The reels 19 diameter is of such a dimension as to be able to slide out of slits 14 and 15 on the pipe sleeves' 13 both sides in such a way that a line 21, preferably a wire of woven steel, can freely glide along the sleeves' 13 outer body. The lines' 21 one end is fastened to the front side of the sleeve 13 at 22 (see fig.l), and with its other end is fastened to the upper inner bent portion of the control pedal 12 at 23. The control pedal 12, in its turn, composes part of the sleeves' 13 exterior moving part 24, that in order to move along the pipe sleeve, can, as shown in fig.5, be fashioned with two reels 25 and 26), that are mounted on each side of the pipe sleeve 13. A reel, or a glide surface of some fabricated material should also be able to be mounted on to the inner edge of the control pedal 12 whose inner edge can lie beside or against the sieves' 13 outer body when the part is in upwards motion.

A pull spring 27 at 28, with one end connected to the pipe sleeves' 13 fixed upper end 29 and its other end 30 connected to the bars' 17 lower ended lead support foot 31. The pull spring 27 is, according to proposed design, placed exterior to the pipe sleeve 13, but can also, within the framework of the attached pattent claim, be placed inside the sleeve or have another type of construction, as long as its function is to assist the bar 17 upwards within the pipe sleeve 13. A spring (not shown) with a spring tension, that would be less than the tension of pull spring 27 could be connected to guide the control pedal 12 to its lower position (according to fig.3) with the aim of holding the line taut.

The support foot 31 has wheels 32 attached in pairs (with space in between each other) , in order to, in a stable fashion, be able to lift the applicable wheeled vehicle that this mechanism is attached (for example a hand cart or other vehicle) , up or down one or more stairs. Within the framework of the attached patent claim, the total number of wheels can vary on the support foot, other than the four shown, or, the lower end of the bar 17, can have another type of support foot design in the form of rubber, plastic or other material that can slide along the transport surface without damaging or marking it.

Figure 6 shows an alternative design of the pull springs' 27 lower receiving plate 33. This has the form of a double con¬ nected eyelet with two positions for the pull springs' eye hook - one position for transportation up a stair or stairs by means of the mechanism according to the invention, and the other for transportation down the stair or stairs. These positions can be manually adjusted by the operator by moving the end of the spring over to the appropiate position.

Figures 7a - 7d show schematicly how a handcart can be trans¬ ported up a flight of stairs by means of the mechanism 2 according to the invention. Fig. 7a shows how the handcarts' 1 wheels 8 rest against a step 34. Figure 7b shows how the mechanisms' 2 control pedal 12 distributes an applied force by the operator of the vehicle, as he/she pushes the control pedal down in the direction of the arrow 33, at the same time as he/she pulls up on the handles of the vehicle in the direction of arrow 36. The force that the operator applies to the control pedal 12 minimize the force needed to pull up on the handles, which in its turn, lifts the vehicle upwards at the same time as it draws it against and up the next step 37, all the while applying the nessesary force needed by the operators' arms and the leg which is applying the inital downwards force to the control pedal 12. Fig. 7c shows how the wheel 8 has reached the next steps' plateu 37, thereafter the control pedal 12 is released and the bar 17 moves in the direction of the arrow 38 within the pipe sleeve 13 by means of the pull spring 27. Fig. 7d shows how the bar 17 is guided into its origional position within the pipe sleeve 13, so that the support foot 31 can swing in over and against the next stairs' plateu 37. With transport being made down a set of stairs or other bilevel surface, the function is in the reverse, with the difference being that the support foot 31 swings over to its position against the load flange 6. This can also be done with a spring attachment according to fig. 6.

Figure 8 shows another possible design of the mechanism according to the invention, in which a bar 117 is telescopicly moved within a pipe sleeve 113 in which both the bar and sleeve preferably have a rectangular cross section. On the upper end of the pipe sleeve is a part 129 fixed on which a spring 128 is attached. The other end of the spring is attached at 130 beside a wheel 132 supplied support foot 131. At the base of the pipe sleeve, a connection plate 116 is affixed in order to connect the mechanism to a hand driven vehicle, pushcart, wheelchair or other transport device. Chain wheels 141 and 142 are attached on a certain distance away from each other, on the pipe sleeve 113 and a chain 143 is passed between these wheels. A follower 144 that is attached at one of the chains' links is provided with a peg 145 at its other end, of which is fixed to a hole (not shown)in the bar 117, and is movable within a slit in the pipe sleeve so that the bar can move up and down in relation to the pipesleeve. A reversable motor 146 and a transmission device 147 is mounted on the pipe sleeve 113 in order drive the lower chain wheel in both directions. This action is controled via control switches mounted in a control box 148 that is preferably mounted to one of the handles of the transport vehicle and is connected to the motor and transmission via a harness 149. The motor 146 and transmission 147 are schematically shown in the drawings. These units can, of course, be mounted up to and beside the upper chain wheel 141 and can also be smaller in size and have another construction than what is shown.

During transport of the vehicle down a flight of stairs, it is important that the wheels come so far in and up on the stair plateu as possible, in order to minimize the risk that the vehicle goes past the plateu edge. For this purpose the lower end of the mechanism can be designed as shown in the cross section in fig.9. The support foot 131 is attached at 150 on the bar. A rod 151 is attached to the support foot 131 and is controlled by a controller 152. A push spring 153 is attached to the controller in order to press the rod and there upon also the support foot, in the direction of the arrow 154. When the operating device, made up of a motor, transmission and chain drive is activated, the pull spring 127 (shown in fig.8) is streched. After a certain position is reached, the pull springs' force overcomes the push springs' 153, and the support foot swings out to the shown position in figs. 8 and 9. When the pipe sleeve 117 and the bar 113 return towards each other, the opposite action is preformed i.e. at a certian position the pull springs' force is slackened and the push spring 153 pushes the support foot to such a position as to make the support foot parallel with the mechanisms' vertical plane. Of course this motion of the support foot can be done by other means, but optimally a spring should be used.

A proposed design of the mechanism according to the invention specifications has been described with reference to the attached drawings, but can, of course, be modified within the framework of the attached patent claim.

Claims

1. A stair walking mechanism, which is mountable to a hand driven vehicle (1) for example a handcart, wheelchair or similar transport device, characterised by two parallel passing elongated, primary and secondary parts (13,17/113,117) of which said primary part is connected or joined to the vehicle (1) and said secondary part is equipped with a support foot (31/131) whose lower end is constructed to make contact with a surface (34,37) on which the vehicle rests, with the goal of transporting goods up or down stairs or other bilevel surface and an operating device that is equiped with said secondary parts' operating pedal (12) or follower (144) and which, when activated, is equiped in such a way as to guide the support foot up and/or down in relation to the vehicle, whose means can be equiped to guide said elongated parts to such a position in which the support foot is found to be in an upper position.

2. The mechanism, according to claim 1, characterised in that said primary and secondary parts (12,17/113,117) consist of two telescoping, one inside the other, guided pipes or bars, which have optimally the same cross sectional shape.

3. A mechanism according to claim 1 or 2, characterised in that said operating device incorperates an, optimally, reversable motor (146) , that, via a gearing or transmission (147) , is equipped to drive a chain (143) or similar linked structure, whose follower (144) is fixed and that the named motor can be controlled by the person who operates the vehicle.

4. A mechanism according to claim 1 or 2, characterised in that said control pedal (12) is attached to a line (21), preferably a wire of woven metal, that is guided over the upper end (19) of said secondary part and whose ends are connected with, in part, to said control pedal (12) .

5. A mechanism according to claim 4, characterised in that said secondary part (13) , whose upper portion is fashioned with a slit (18), in which a reel (19) is, spin free mounted and that, said line (21) , is passed over said reel (19) .

6. A mechanism according to claim 5, characterised in that said control pedal (12), which makes up a part of a vehicle (24), that is guidable by means of a control device along said primary part (13) .

7. A mechanism according to claim 6, characterised in that said control device on the exterior moving part (24) which is made up of, on each side of the primary part (13) , attached reels (25,26) that are spin free mounted on the primary part.

8. A mechanism according to any of the claims 1 - 7, charac¬ terised in that said means (27) comprises a spring, optimally a pull spring, that is connected between the primary and secondary parts (13,17) .

9. A mechanism according to claim 8, characterised in that said spring (27) is a pull spring, and comprises, on its lower end, an eye hook to which it then can be attached to a reciever plate which is fixed onto the afore mentioned support foot, and is formed in such a way as to provide two positions for said eye hook, and that said support foot (31) is movably connected with the secondary parts' (17) lower end, and is, optimally, on its outer end fashioned with a support wheel (32) with which, in the primary position, the support bar strives to reach a retracted position for transport up a stairway and in the secondary position, an extended position for transport down a set of stairs.

10. A mechanism according to any of the claims 1 - 7, charac¬ terised in that said means comprises a primary spring, preferably a pull spring (127), that is connected between the primary and secondary parts (113,117) and a secondary spring, preferably a push spring (153), that is connected between the bar and the lower end of the secondary parts' (17) attached support foot (131) with which the primary and secondary springs' characteristics are such, as when the secondary part is guided downwards at an exact position, enables the primary spring to guide the support foot to such a position that it reaches inwards onto the stair plateu on which it lies against.