DE102009052253A1 - Wheelchair for climbing e.g. spiral stairs, has running surface whose segment lies in direct proximity to step edge such that ends of pressure springs are connected with surface and placed on nearest level during rotation of rear wheels - Google Patents

Abstract

The chair has two rear wheels (6) whose running surface (14) is connected with a hub (5) by gas pressure springs (15). The running surface of the rear wheels is sectionally deformed in a radial direction, where radial distance of a segment of the running surface to the hub is reduced when nearest level of steps and/or stairs is reached. The segment of the running surface lies in direct proximity to a step edge such that ends of the gas pressure springs is connected with the running surface and placed on the nearest level during rotation of the rear wheels.

Description

State of the art

The invention relates to a wheelchair with which the driver can also overcome steps and stairs in both directions and other road obstacles without outside help and without additional provided on the stairs technical aids.

For wheelchair users it is only possible to overcome differences in height that are exclusively connected by steps or stairs, with only a few exceptions. A wheelchair is known with a stair climbing device having on each side two spaced apart in the direction of travel, arranged on parallel wheel axles wheels, which are supported on each side in a two-armed rocker. In the middle between the wheels, the rocker is rotatably mounted and rotatable about this adjusting axis via a drive unit, which is optionally also activated for the drive of the wheelchair. For climbing stairs, one of the drive unit outgoing first drive connection is provided, which drives the two wings in ascending or descending, which is pivoted about the adjusting axis and the axis of standing on the stage wheels until the other two wheels on the upstanding wheels away is moved to the step surface of the next higher or lower level. The wheelchair is driven by a second drive connection from the drive unit to at least one wheel ( EP 1 186 284 A1 ). The disadvantage of this wheelchair is that the wheelchair user still requires a wheelchair driver, ie an assistant, to climb the stairs. In addition, the invention is limited to wheelchairs with relatively small wheels, so that they are not suitable for the majority of hand wheelchairs that are manually moved over their large rear wheels.

Johnson & Johnson developed the "Ibot" wheelchair in the USA at the end of the 1990s, which allows wheelchair users to easily negotiate steps and even longer stairs. The wheelchair has two wheels of equal size on each side, of which two wheels sitting on one axle are placed on a step and locked. Thereafter, the other two wheels swing around the former and sat on the next step, while the wheelchair is lifted with it, ie when climbing the wheelchair is only on two wheels. Six gyroscopes and electronic sensors keep it in a vertical position or the seat horizontally. In addition, erecting the wheelchair on two wheels still serves as a lift to allow wheelchair users to reach higher-level facilities and objects ( Der Spiegel 34/1999, p. 165 and Internet link to the iBOT 4000 Mobility System). According to the latest information, however, the distribution of this wheelchair was discontinued, which is probably due to its extremely high price.

In contrast to this technically highly complex solution, the Mechatronics Center of the Leibniz University of Hanover has developed a lower priced wheelchair prototype suitable for wheelchairs, with which the driver can overcome steps and short stairs without assistance. He also has on each side two equal-sized wheels, which are pushed up with cranks, but always sit all four wheels on the steps. A contact clip detects the approach to a step edge, simple tactile sensors control the lifting process and a combination of contact switch and ultrasonic sensor detect the step height. The seat of the wheelchair, which is attached to the chassis with a swivel arm, is kept in a horizontal position during the inclination of the landing gear (Pressetext.deutschland 21.09.2007). According to the developers, the wheelchair is intended above all to overcome individual steps or step groups. For overcoming entire floors, the mechanism is too slow.

However, another group of technical solutions for wheelchairs with a stair-climbing function, which manage to climb stairs without assistance, but require devices or attachments on the wheelchair normal design itself, take over the function of climbing stairs, while the wheelchair up the stairs or slide down. These are usually retractable and extendable cams ( DE 197 48 887 A1 ), Timing Belt Tracks ( DE 38 27 607 A1 ) or caterpillars ( DE 10 2006 049 711 A1 ), which, after folding out or extending from the wheelchair, sit on the steps and gain a hold through positive locking with the step edge. The disadvantage here is that these devices or attachments constantly transported with the wheelchair or must be connected in place only with this. The former is associated with an additional effort, the latter with an additional assembly and disassembly effort.

Finally, a wheelchair with stair climbing function is known in which the drivable rear wheels are each attached to a lever consisting of parallel offset ends levers, wherein the lower end of each lever is extendable. The approximately perpendicular connection of the upper and lower end of each lever are connected to each other via an axis which in the between the seat and footrest of the wheelchair also approximately perpendicularly extending frame parts rotatable is stored. The frame part is supported by small front wheels on the ground. To climb stairs, this is pulled out of our end of the lever and tilted by about 45 ° relative to the seat forward. As a result, the seat occupies a stair driving position, ie the rear wheel fasteners approach the seat, which remains approximately horizontal. The extended end of the lower end of the lever is approximately parallel to the upper edge of the staircase and supported on a step surface. Now the rear wheels can be turned to climb stairs manually or by motor, rolling from step edge to step edge. In order to avoid slippage, extendable nubs are arranged on the rear wheels. The disadvantage of this wheelchair is that despite the nubs there is a high risk of slipping here. Even if the slipping is interrupted when the extended lever hits the next lower step, it is uncomfortable for the wheelchair user. In turn, it is cheaper then to design the rear wheels as revolving drive wheels, whereby however the advantage of the application for hand wheelchairs is lost. In addition, the arrangement of retractable and retractable knobs is associated with additional effort.

Incidentally, the question of safety in general, even with the above-mentioned wheelchairs with smaller wheels, of extraordinary importance. In high-tech wheelchairs, such as the "Ibot" wheelchair, the safety, including the security against slipping, is ensured by a high degree of additional controls and controllable devices. In other technical solutions, safety is achieved by constructive measures, for example, the wheelchair with stair climbing function ( DE 101 56 546 A1 ) by the displacement of the seat backwards to the periphery of the rear wheels out and reaching below the axis of the rear wheels, achieved.

A major disadvantage of all mentioned wheelchairs, finally, is that they are not or only partially suitable for overcoming spiral staircases and pedestals. In most technical solutions, the lifting mechanism requires an unaltered tread over the entire width of the staircase, which is not the case with spiral staircases. Although wheelchairs equipped with caterpillars are curve-like, they particularly stress the step edges, in particular because of the different speeds of both caterpillars to be traveled in curves, which leads to rapid wear of the stairs.

The invention and its advantages

The wheelchair according to the invention with the characterizing features of claim 1 has the advantage that the technical means that allow climbing stairs, relatively simple in design, robust and can be produced in a simple manner. At the same time they enable a low-friction, cushioned ride on the plane and are safe against slipping off the stair nosing. In addition, the control effort for temporally and locally limited change in the tread of the rear wheels of the wheelchair in a technically simple manner to realize, so that from this side of the wheelchair according to the invention is sufficiently robust and less susceptible to interference. It is also advantageous that the solution according to the invention allows stair climbing regardless of the shape of the steps or stairs, so helical and pedestal stairs without additional effort and gently with the wheelchair can be overcome, the steering ability as in a conventional manually operated wheelchair remains.

These advantages are achieved in that the scope and thus the running surface of the rear wheels of the wheelchair is designed to be flexible throughout, d. H. the rear wheels no longer have a rigid rim. This makes it possible to adjust the tread of the rear wheels of the task, namely rollers or stairs to adapt. This adjustment is made by the fact that each of the step edge or generally the edge of an obstacle opposing elbow of the tread of the rear wheel is enabled to quasi make a positive connection with the obstacle, so that the closest to the plane to be reached spoke arranged element on this plane can put on. To roll on the plane, these elbows must then be returned to their original position or form, so that they form a circular tread in their entirety again.

Stair climbing can be compared with a Stelzvorgang, the spoke-like elements perform the function of a stilt. The positive engagement used for the safety of climbing stairs is significantly more pronounced in the present invention than in the publications cited in the prior art. He is no longer formed solely by the surface texture of the tread of wheelchair wheels or by additional extendable on the rear wheel mold elements, but arises only for the purpose and at the time of overcoming obstacles, such as steps and stairs, by a temporary and partial deformation of the otherwise circular Circumference of the rear wheel in the direction of the hub, as a result of the force caused by the driving torque of the rear wheels force on the voltage applied to the step edge elbow of the tread.

According to an advantageous embodiment of the invention, the running surface of each rear wheel is formed from individual elbows, which are each secured to the outer end of the spoke-like elements, ie, the tread is not a closed peripheral surface. The spokes connected to the hub of the rear wheel connecting elements arranged in the elbow are variable in their radial length. As a result, the abutting with his elbow to a step edge element under the force caused by the drive force a piece towards the hub are shortened, so that a lying in the direction of this element lying spoke-like element arranged with the attached sheet on him on the next level to be reached can sit safely. Since the elbows are not connected to each other, so the tread of the rear wheel in the area of the step edge opens briefly, so that it is here exclusively a Stelz- or walking process.

According to another advantageous embodiment of the invention, the running surface of each rear wheel is formed as a closed flexible tires, attack on the inside of the spoke-like elements arranged. This continuous tread improves the handling characteristics of the wheelchair and allows a positive connection between the elbow and step edge regardless of the relative position of the rear wheel, so that consuming and often interference-prone sensors for detecting the respective wheel position can be omitted to the step edge. In addition, the elbow lays flat against the tread surface of the step, so that increases the bearing surface between the rear wheel and tread and thus causes an improvement of the static friction and thus the safety when climbing stairs. A further advantage is that the cost of connection between spoke-like elements arranged and tread is less than single flexible elbows.

The positive engagement of the tread of the rear wheels with a step can basically be achieved in two ways: According to an advantageous embodiment of the invention, the reduction of the distance between abutting on the step edge elbow and hub by reducing the radial length of the or the elbow reaching supporting spoke-like arranged elements. For climbing stairs, the length of the elements located immediately in front of a step edge is reduced so far that the flexible sheet located between these elements pushes towards the wheel hub when approaching the step edge and in this way creates a positive connection between the step and rear wheels. Upon further rotation of the rear wheels, the element located above the step edge sets on the tread surface of the step, wherein the flexible elbow of the tread continuously applies to the tread surface and further transmits the forces introduced by the drive of the rear wheels until the driving resistance force and the slope force are completely overcome , the weight of the wheelchair on the front wheels on the road and on the above flexible elbow distributed to the next higher level and with further forward movement of the wheelchair whose rear wheels lift off the road and roll on the first tread. Once the wheelchair has negotiated the step or stairs, the elements return to their original length and tighten the flexible sheet or pieces to the original circular tread. When shutting down a step or stairs, the process just described runs in reverse order.

After this in this other advantageous embodiment of the invention, only the length of this located between two spoke-like elements arranged elbow is increased to reduce the distance between adjacent to the step edge elbow and hub, without the radial length of the spoke-like elements arranged must be changed. This can be achieved, for example, by changing the inherent rigidity of the relevant elbow piece, by venting the air in the region involved in overcoming the step in the case of an air-tired tread. This of course assumes that the tires of the rear wheels consist of individual chambers. But it is also possible for the stairs to let the air completely out of the tire, since to overcome larger stairs anyway several revolutions of the rear wheels are required, d. H. the entire tread is involved in the process. The advantage of this embodiment of the invention is that rigid and immutable in their length spoke-like arranged elements can be used. However, a compressor for inflating the tires of the rear wheels is required for the preparation of the driving readiness of the wheelchair after climbing the stairs.

According to an additional advantageous embodiment of the invention, the spoke-like elements are guided in a rigidly connected to the hub rim. This simplifies their connection to the hub, since the transverse forces are absorbed by the rim. In addition, the rear wheel gains stability.

According to another advantageous embodiment of the invention, the adjustment of the length of the spoke-like elements arranged automatically. For this purpose, arranged on the wheelchair sensors can signal the approach to a step and the radial length of the immediate vicinity reduce elements to a required extent. The change in length can also be triggered manually by the wheelchair user when approaching a step or stairs.

According to another advantageous embodiment of the invention, the spoke-like elements arranged in their spring travel limitable spring elements. When approaching a step or stairs, the limitation of the spring travel is removed or disabled, so that the upstanding on the floor spring elements initially compress by the weight of wheelchair and wheelchair users. When driving counter to the edge of a step, the force that produces the narrow support surface of a step edge acts on the tread on the spring elements located in the immediate vicinity and presses them together, so that it is used to deform the tread of the wheel of the wheelchair and thereby the positive connection with the step edge comes. The spring force of the spring element and the elastic potential of the tread cancel the deformation as soon as the wheel returns to a flat surface, ie either the tread or the end of the stairs. The process of reducing the radial length and adjusting the initial length of the spring elements thus takes place automatically in this variant of the invention. This has the advantage that unevenness on roads and stepped differences in height are compensated in whole or in part, since the profile of the positive connection of the arc or the tread of the tread forms in the direction of the hub of the rear wheels, thereby introduced due to the unevenness loads not only by the spring elements cushioned, but can be compensated. Consequently, the relative movement of the rear axle of the wheelchair is reduced to the road, which u. a. causes the inclination change of the seat of the wheelchair when climbing stairs is limited. In addition, the suspension gives the wheelchair a smoother ride and thus greater driving safety and improved ride comfort.

A particularly advantageous embodiment of the invention in this respect is to use as spring elements gas springs. Gas springs respond to any resistance force F _W in the longitudinal direction of their piston rod automatically, ie they require no additional control. In addition, they have a long travel at relatively low progression of their spring characteristic, which in turn favors the formation of a positive connection of the elbow of the tread at a step edge. An additional advantage of gas springs is that their spring rate can be varied by adjusting the gas pressure. By such a presetting an adaptation to both the loading conditions of the wheelchair as well as to the lengthening of each gas spring required when climbing stairs is possible. The latter is not necessarily required in any case, because by the narrow step edge per area is exerted a greater force on the located directly above and / or below the step edge gas spring, so that the piston rod is pressed further into the gas space than on a flat surface. The spring action of the gas springs is z. B. also exploited in the spring system for vehicles, in which the gas springs connect the hub with the rigid rim of the wheel ( DE 20 2005 010 968 U1 ). However, in this use of the gas springs, the rim is displaced relative to the wheel axle in order to cushion a shock already in the wheel and not to be transferred to frame or body parts.

Finally, it is an advantageous embodiment of the invention is to increase the static friction of the wheelchair wheels on the road at the moment of impressing the located at the step edge spoke-shaped elements by increasing the contact surface between the wheel and the roadway, similar to a tire with too low a tire pressure , This is done in turn by reducing the radial length of that or those spoke-like elements arranged, whose or the outer end is located in front of a step on the road or just above it. The greater static friction between the wheel and the roadway serves as a safe abutment during the radial shortening of the elements located on the step edge immediately before lifting the wheel.

Further advantages and advantageous embodiments of the invention are the following description, the drawings and claims removed.

drawing

An embodiment of the invention is illustrated in the drawings and described in more detail below. Show it

1 a schematic diagram of the wheelchair according to the invention,

2 the rear wheel of the wheelchair in front of a staircase,

3 the rear wheel of the wheelchair as it approaches the stairs,

4 the rear wheel of the wheelchair when lifting at the stairs and

5 the individual phases of the rear wheel of the wheelchair when overcoming the entire staircase.

Description of the embodiment

Of the various possibilities described above of achieving a positive connection between a wheel and a stage show the 1 to 5 the inventive principle based on a conventional, driven by its rear wheels wheelchair, which have a closed tires. 1 shows a schematic representation of the wheelchair according to the invention, on a flat road surface 1 standing, in the side view with its essential for the stair climbing function components. It consists of two small front wheels 2 with one axis each 3 that have a chassis 4 with the hubs 5 the opposite to the front wheels 2 larger rear wheels 6 the wheelchair are connected. About the chassis 4 can the front wheels 2 in the vertical direction 7 and in the horizontal direction 8th in their distance to the rear wheels 6 to be changed. Furthermore, the front wheels 2 be driven. On the chassis 4 is a seat 9 with a backrest 10 arranged. Both are in a horizontal direction 11 , vertical direction 12 as well as in their inclination 13 to the roadway 1 adjustable. About the vertical adjustment 12 is the distance of the seat 9 to the hub 5 the rear wheels 6 variable.

The rear wheels 6 consist of an endless tread 14 from an elastic material commonly used for tires, for the clarity of illustration of the principle of the invention only about eight spoke-like arranged gas springs 15 with the hub 5 are connected. Coaxial to the hub 5 is a double-walled rim 16 over crosswise struts 17 with the hub 5 connected in which the gas springs 15 are guided. The rear wheels 6 The wheelchair can be driven manually or by a motor.

The wheelchair is with a weight F _G , z. As that of the wheelchair user, charged together with the weight of the wheelchair a normal force F _N on the road 1 exercises. Between roadway 1 and tread 14 there is a frictional force F _R.

In the following 2 to 5 is to illustrate the process of climbing stairs only a rear wheel 6 of the wheelchair and only with his actively involved in the stairs, ie changing components shown. 2 shows the starting situation of the rear wheel 6 when approaching a staircase 18 with risers 19 and step 20 , Both parts of the step abut at a step edge 21 together. To improve the static friction F _R was the piston of the seated on the road gas spring 15 slightly retracted, so that by the weight F _G the present in the range of normal force F _N contact surface between the road 1 and tread 14 slightly enlarged, also known by the term "Laces", and in the 2 to 5 with the number 22 designated. When rolling up to the bottom step of the stairs 18 The length will also be the following on the tread 1 putting on gas springs 15 decreases, so that between the shortened gas springs 15 lying elbow of the tread 14 to the hub 5 can be pushed in.

3 now shows the rear wheel 6 after it, under the action of the drive torque M _D at the step edge 21 the stairs 18 moved up. When the torque M _D continues, the step edge sets 21 the elastic tread 14 of the rear wheel 6 a resistance force F _W against, due to the only linear attack surface of the step edge 21 impressing both the elbow of the elastic tread 14 in this area as well as the piston rod already above the step edge 21 located gas spring 15 and thus causes their shortening. This leads to the above-described temporally and locally limited deformation of the tread 14 the rear wheels 16 providing a secure fit between the step and the rear wheels 6 allows. On the step 20 An upper latsch begins 23 form, now a part of the Normakraft F _N acts on this area.

Out 4 Now it can be seen that with continued rotation of the rear wheel 6 the piston is above the step edge 21 located gas spring 15 on the tread 20 touches on the deformation of the elbow of the tread 14 opposite of the climbing direction wanders and increases in the radial direction. This also increases the area of the upper laces 23 on the first step 20 further, whereby also initiated by the drive torque M _D driving forces on the rear wheel 6 can be further enlarged, supported and transmitted until the driving resistance and the downhill power are overcome and the weight F _{G of} the wheelchair completely on the front wheels 2 and in the upper latsch 23 on the first step 21 supports and thus the normal force F _N in Laces 22 ( 3 ) between the rear wheels 6 and the roadway 1 is compensated, so that with further forward movement of the wheelchair, the rear wheels 6 stand out from the road. At that moment, that will be on the road until then 1 rising gas spring 15 automatically relieves and recovers its initial length, while she is this elbow of the tread 14 brings back into the circular shape and fixed in this.

This process repeats itself until the last step of the staircase 18 is overcome. The case of the tread 14 of the rear wheel 6 gone through phases are in 5 in each case in the 3 known initial deformation and the 4 shown known maximum deformation. The same parts as those already shown in the preceding figures have been given the same reference numerals used in these figures. Out 5 is recognizable that the tread 14 of the rear wheel 6 until it is the three steps of the illustrated staircase 18 has overcome six times deformed, wherein the initial deformation continuously merges into the maximum deformation and the latter is also continuously broken down again, similar to the crawl of a snail.

Also the front wheels 2 can support the steps of climbing the features of the rear wheels 6 exhibit.

All in the description, the following claims and the drawings illustrated features may be essential to the invention both individually and in any combination.

LIST OF REFERENCE NUMBERS

1

roadway

2

front wheels

3

Axle front wheel

4

chassis

5

Hub rear wheel

6

rear wheels

7

Adjustment vertical direction

8th

Adjustment horizontal direction

9

seat

10

backrest

11

Adjustment horizontal direction

12

Adjustment vertical direction

13

Adjustment tilt

14

tread

15

Gas spring

16

rim

17

pursuit

18

stairway

19

riser

20

tread

21

step edge

22

Latsch

23

Upper Latsch

F _G

weight force

F _N

normal force

F _R

friction force

_FW

resistance

M _D

torque

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 1186284 A1 [0002]
• DE 19748887 A1 [0005]
• DE 3827607 A1 [0005]
• DE 102006049711 A1 [0005]
• DE 10156546 A1 [0007]
• DE 202005010968 U1 [0019]

Cited non-patent literature

• Der Spiegel 34/1999, p. 165 [0003]

Claims (11)

Wheelchair for climbing stairs, which has at least one front wheel ( 2 ) and two in relation to the step height of the stairs ( 18 ) larger rear wheels ( 6 ) whose tread ( 14 ) via spoke-like elements ( 15 ) each with the hub ( 5 ) of the rear wheels ( 6 ), characterized in that the tread ( 14 ) of the rear wheels ( 6 ) at least partially deviating from the circular peripheral shape deformable in the radial direction and without rim directly on the spoke-like arranged elements ( 15 ) with the hub ( 5 ) of the rear wheels ( 6 ), wherein to reach the nearest level of the step or stairs ( 18 ) the radial distance of that elbow of the tread ( 14 ) to the hub ( 5 ) at or in close proximity to the step edge ( 21 ), so that when the rear wheels ( 6 ) with the tread ( 14 ) connected end of the closest to the plane to be reached spoke-like arranged element ( 15 ) at this level. Wheelchair according to claim 1, characterized in that the tread ( 14 ) of each rear wheel ( 6 ) by only with the free end of the spoke-like arranged elements ( 15 ) Connected elbows is formed. Wheelchair according to claim 1, characterized in that the tread ( 14 ) of each rear wheel ( 6 ) is designed as a closed flexible tire. Wheelchair according to claim 1, 2 or 3, characterized in that to reduce the distance of the at the step edge ( 21 ) adjacent curved piece of the tread ( 14 ) to the hub ( 5 ) the radial length of the or the sheet piece supporting spoke-like arranged elements ( 15 ) is reduced. Wheelchair according to claim 1 or 3, characterized in that to reduce the distance of the at the step edge ( 21 ) adjacent curved piece of the tread ( 14 ) to the hub ( 5 ) only the length of this between two spoke-like elements ( 15 ) located sheet is increased. Wheelchair according to one of claims 1 to 5, characterized in that the spoke-like arranged elements ( 15 ) in a rigid with the hub ( 5 ) connected rim ( 16 ) are guided. Wheelchair according to one of claims 1 to 6, characterized in that the adjustment of the distance of the or the curved pieces of the tread ( 14 ) to the hub ( 5 ) automatically. Wheelchair according to one of claims 1 to 7, characterized in that the spoke-like arranged elements ( 15 ) consist of in their travel limitable spring elements. Wheelchair according to claim 8, characterized in that the spring elements of gas pressure springs ( 15 ) consist. Wheelchair according to claim 9, characterized in that the adjustment of the length of the gas springs ( 15 ) is pressure-dependent. Wheelchair according to one of claims 1 to 9, characterized in that for climbing stairs, the radial distance of that or those elbows of the tread ( 14 ) is reduced slightly before or immediately above the carriageway ( 1 ) or on or immediately above the step ( 20 ) the stairs ( 18 ) are located.

Images