EP2281541B1 - Adjustable support stand with automated deployment - Google Patents

Description

The present invention relates to a variable length stand having a main body, an extendable and retractable foot with respect to said main body, and an actuator comprising a rotary output shaft motor and a worm gear to convert a rotation of said motor shaft in a linear movement of said foot relative to the main body.

Such a variable length crutch has been described in the international patent application WO 99/00101 . In this stand of the state of the art, the extension or retraction of the stand is controlled by simple switches. Limit switches stop the motor when the actuator reaches the end of the stroke. When the engine is stopped, a brake must be activated to maintain the desired position of the stand.

Such an arrangement, however, has certain disadvantages. First, only the end positions are clearly defined, and the user can not easily stop the deployment of the stand in a precise intermediate position. Especially since crutches are often used in pairs, and normally both crutches will have to be adjusted to the same length with some precision, the customizing the stand will therefore require the movement of limit switches, which is a complicated operation. In addition, the brake introduces an additional mechanical element that can be a source of failures. Reliable operation is one of the most important criteria of use for a crutch.

An object of the present invention is therefore to provide a variable length stand allowing precise positioning and reliable locking on any intermediate position in its deployment stroke.

With this object, in a variable length stand according to the present invention, the worm gear is irreversible, and the actuator also comprises a programmable engine control module, said module being connected to said motor in order to control the extension. and / or retracting the stand to a preprogrammed length and stopping the motor when said length is reached.

The stand of the invention further comprises a first tube, and a second tube, the foot being fixed on the first tube, the second tube being fixed on the main body, and the first and second tubes being mounted telescopically relative to to one another. Thus, the first and second tubes can form a telescopic sheath, serving in particular to protect the worm gear transmission.

Said worm gear transmission comprises a threaded rod coupled to the motor shaft, a nut secured to the foot and engaged on said threaded rod, and a linear guide to prevent the rotation of the nut relative to the main body, while allowing its linear movement. In this way a worm gear is obtained with great strength and limited space. However, alternative worm transmission arrangements could be considered by the person skilled in the art depending on the circumstances. Even more preferably, the nut may be of synthetic material. A plastic nut reduces the friction of the worm gear and helps to dampen shocks.

Thanks to the programmable control module and the extension sensor, the extension and / or the retraction of the stand can be controlled and stopped at at least one easily programmable position with great precision. Thanks to the irreversible nature of the worm gear transmission, the stand leg remains reliably locked at this preprogrammed position, regardless of the support force exerted on the leg of the stand. In addition to its innovative ergonomics, the crutch has innovative handling features. It also presents the specificity of being a dynamic assistance tool for recovery.

Preferably, the programmable control module may be an electronic module, which may comprise a specialized logic circuit or a general purpose processor.

Preferably, said module may comprise a touch and / or voice user interface connected to said control module to allow the user to control said extension and / or retraction of the stand. As "touch interface" we mainly consider control buttons. As "voice interface" we consider any device that can react to sound signals emitted by the user.

Preferably, said motor can be electric and the actuator also include a source of electrical energy. Such an engine offers advantages as much by its low weight and size as by the precision of its control. Even more preferably, said source of electrical energy may be formed by at least one rechargeable battery, and possibly also include a socket for recharging said batteries.

Preferably, the stand of the invention may further comprise an interface for programming said control module.

Preferably, the stand of the invention may further comprise a support that can be fixed on the foot in order to keep the standing stand without the need for further support.

Preferably, the main body of the stand of the invention may comprise a handle and a support for forearm or armpit.

The invention also relates to a method of using such a stand, wherein said control module activates the motor for the extension and / or retraction of the stand to a preprogrammed length and stops the motor when said length is reached, and this length is then maintained against axial forces by said irreversible worm gear transmission.

Advantageously, a user can take support on the folded stand to move from a sitting position to a standing position, and then proceed to control, through said control module, the deployment of the stand to rely on it to walk. Since the length of deployment of the stand is automatically controlled, the user can use it in this way without making any particular effort to adjust the deployment length each time.

Advantageously, said control module can activate the motor by transmitting a number of pulses proportional to the distance between an initial length and said preprogrammed length. In this way, the control module can regulate the extension and / or retraction of the open loop stand without the need for a position sensor.

Advantageously, the control module can regulate the speed of said motor by modulation in width of said pulsations. Thus, the speed of extension and / or retraction of the stand can be varied depending on the circumstances.

In particular, the speed of the motor could be progressively decreased as it approaches said preprogrammed length and / or gradually increased during an initial step of the extension and / or retraction of said stand to avoid stopping shocks and / or starting which could damage the actuator of the stand.

• La figure 1 montre une béquille suivant un mode de réalisation de l'invention en position rétractée,
• la figure 2 montre la béquille de la figure 1 en position déployée,
• et la figure 3 montre une coupe transversale de la béquille de la figure 1 dans le plan III-III.

Details of the invention are described below with reference to the drawings.

• The figure 1 shows a crutch according to one embodiment of the invention in the retracted position,
• the figure 2 shows the crutch of the figure 1 in the deployed position,
• and the figure 3 shows a cross section of the crutch of the figure 1 in the plan III-III.

A variable length crutch 1 having a main body 2 with a handle 3 and a forearm support 4, and a foot 5 is shown in the folded position. In this position, the stand allows persons with reduced mobility to help themselves to get up from a position sits in a standing position by resting on the stand 1, its length in this position being adapted to provide maximum support to the user.

Once the user is in a standing position, he / she can trigger an automatic extension of the stand 1 to reach an extended position such as that shown on the picture. figure 2 . In this deployed position, the stand 1 can be used conventionally to support the standing user.

Both the length of the stand 1 in the folded position as that in the deployed position can be adapted to each individual user. For this, the stand 1 comprises an actuator with, in the main body 2, an electric motor 6 powered by rechargeable batteries 7 and controlled by an electronic control module 8 and programmable connected to a touch control interface in the form of pushbuttons 11 placed on the handle 3.

In a preferred embodiment, the rechargeable batteries 7 are two batteries of 8.4V connected in series, the motor 6 is a brushless motor developing a nominal torque of 16 mNm, and the module 8 controls the motor by a pulse signal Pulse Width Modulation (PWM). The angle of rotation of the motor is thus determined by the number of pulses transmitted by the module 8, while the speed of rotation is inversely proportional to the duration (width) of the individual pulsations. The crutch 1 also has an electrical outlet 25 for recharging the batteries 7.

The drive shaft 10 is coupled to a threaded rod 12 through a coupling 13. This coupling 13 is rigid and without play. This threaded rod 12 is in engagement with a nut 14, thus forming a worm gear, the materials and the thread pitch are chosen so that it is irreversible, that is to say, an axial force on the nut 14 can not cause a substantial rotation of the threaded rod 12, although an effort rotation on the threaded rod 12 causes an axial displacement of the nut 14.

The nut 14 is coupled to the foot 5 through a first hollow tube 15. This first tube 15 is telescopically mounted relative to a second tube 16 fixed on the main body 2 of the stand. In order to avoid the rotation of the nut 14, the first tube 15 and the foot 5 with respect to the main body 2 when the Threaded rod 12 rotates, the first tube 15 has a longitudinal groove in engagement with a screw 17 fixed radially on the second tube 16, so as to form a linear guide, as illustrated in FIG. figure 3 . Thus, when the stand 1 is in a folded position, as illustrated in FIG. figure 1 , a simple push of a button 11 can activate the motor 6, rotating the threaded rod 12 so as to deploy the first tube 15 and the foot 5 to an extended position relative to the main body 2, such as that illustrated in the figure 2 . When the user wishes to fold the stand 1, another pressure on a button 11 can activate the motor 6 in the opposite direction, rotating the threaded rod 12 so as to fold the first tube 15 and the foot 5 to the folded position by 2. At the beginning of each movement, the module 8 controls, by PWM, a progressive acceleration of the speed of the motor 6, in order to avoid starting shocks.

Both the folded position and the deployed position can be preprogrammed in the module 8, so that the module 8 controls the stopping of the engine 6 on arrival in one or the other position. However, in the preferred embodiment, the folded position is indicated by a fixed limit stop. In the preferred embodiment, the module 8 controls a progressive decrease in the speed of the motor 6 at the approach of one or the other position, acting in electronic brake mode to avoid shocks and reduce the wear of the motor. actuator. In addition, one or more intermediate positions can also be preprogrammed in module 8, in order to further simplify its adaptation to different users. In order to protect the actuator, the module 8 can also be programmed to stop the motor 6 if a load beyond a preprogrammed threshold is detected, such as, for example, an axial force of 20 N on the rod. This overload could be detected through the power supply of the motor, or, alternatively, by an axial load sensor installed in the axial bearing of the rod.

In the preferred embodiment, the threaded rod 12 is made of brass and has an M8 thread at 2 mm pitch. It is coupled in rotation to the drive shaft 10 by a coupling 14 made of steel, and axially supported by an integrated anti-lock assembly with an intermediate washer of synthetic material, for example polyamide, as an axial bearing. The nut 14 is also made of synthetic material, for example polyacetal, and the tubes 15 and 16 of an aluminum alloy such as that designated AW-AlMgSi according to EN 6060. In this preferred embodiment, the first tube It has an inside diameter of 15.70 mm, an outside diameter of 18.70 mm and a length of 460.00 mm +/- 0.5 mm. The second tube 16 has an internal diameter of 18.80 mm, an external diameter of 22.00 mm and a length of 460.00 mm +/- 0.5 mm. In this preferred embodiment, the first tube 15 telescopes in the second tube 16. Both the outer surface of the first tube 15 and the surfaces internal and external of the second tube 16 are treated by passivation.

On its lower end, the threaded rod 12 also has a block 19 of synthetic material, such as polyacetal, for the internal lateral support of the first tube 15. On its lower end, the second tube 16 has an adjustable handle 22 for the support external side of the first tube 15. An additional support 23, for example of the tripod type, can be mounted, possibly detachably, on the handle 22, in order to be able to maintain the stand 1 standing, when it is in the folded position, without other support. The support 23 may be a laterally unfolding support when the stand 1 reaches a folded position.

In this embodiment, the foot 5 is a foot of elastomeric material, such as rubber, detachably mounted on the lower end of the first tube 15, so as to allow access to the interior of the actuator .

Although the present invention has been described with reference to specific exemplary embodiments, it is obvious that various modifications and changes can be made to these examples without departing from the general scope of the invention as defined by the claims. For example, the stand can also include a more complex interface, or a data connection, to allow the modification of the programming of the control module. Therefore, the description and drawings should be considered in an illustrative rather than restrictive sense.

Claims (15)

1. A variable-length crutch (1) comprising:

   - a main body (2);

   - a foot (5) extensible and retractable with respect to said main body (2); and

   - an actuator including:

   ∘ a motor (6) with a rotary output shaft (9); and

   ∘ a worm transmission for converting a rotation of said motor shaft into a linear movement of said foot with respect to the main body, said worm transmission comprises a threaded rod (12) coupled to the motor shaft (9) and a nut (14) coupled to the foot (5) and engaged on the threaded rod (12);

   characterized in that:

   - said main body further comprises a first hollow tube (15) mounted telescopically with respect to a second tube (16), said second tube being fixed to the main body (2) and before, a screw (17) fixed radially to the second tube (16);

   - said nut (14) is coupled to the foot (5) through the first hollow tube (15);

   - said first tube (15) comprises a longitudinal groove in engagement with said screw (17) on said second tube (16), , so as to form a linear guide for preventing a rotation of said nut (14), of said first tube (15) and of said foot (5) with respect to the main body (2) when the threaded rod (12) turns; and

   - said actuator also comprises a programmable module (8) for controlling the motor (6), said module (8) being connected to said motor (6) in order to control the extension and/or retraction of the crutch (1) to a preprogrammed length and to stop the motor (6) when the length is reached.
2. A crutch (1) according to claim 1, wherein said module (7) comprises a touch and/or voice user interface connected to said control module (8) to enable the user to control said extension and/or retraction of the crutch (1).
3. A crutch (1) according to claim 1 or claim 2, wherein said motor (6) is electric and said actuator also comprises an electrical energy source.
4. A crutch (1) according to claim 3, wherein said electrical energy source is formed by at least one rechargeable battery (7).
5. A crutch (1) according to claim 4, wherein said electrical energy source also comprises a socket (25) for recharging said at least one battery (7).
6. A crutch (1) according to any of the preceding claims, wherein said nut (14) is made from synthetic material.
7. A crutch (1) according to any of the preceding claims, comprising an interface for programming said control module (8).
8. A crutch (1) according to any of the preceding claims, further comprising a support (23) that can be fixed to the main body (2) in order to keep the crutch (1) upright on the foot (5) in the folded position without requiring any other support.
9. A crutch (1) according to any of the preceding claims, wherein said main body (2) comprises a handle (3) and a support (4) for the forearm or armpit.
10. A method of using a crutch (1) according to any of the preceding claims, , wherein said control module (8) activates the motor (6) for extending and/or retracting the crutch (1) to a preprogrammed length and stops the motor (6) when said length is reached, and this length is then maintained in the face of axial forces by said worm transmission.
11. A method of use according to claim 10, wherein a user bears on the folded crutch (1) in order to pass from a seated position to a standing position, and next proceeds, through said control module (8), to control the extension of the crutch (1) to said preprogrammed length so as to rest thereon in order to walk.
12. A method of use according to claim 10 or to claim 11, wherein said control module (8) activates the motor (6) by transmitting thereto a number of pulses proportional to the distance between an initial length and said preprogammed length.
13. A method according to claim 12, wherein said control module regulates the speed of said motor (6) by pulse width modulation signal.
14. A method according to any of claims 10 to 13, wherein the speed of the motor (6) is progressively reduced on approaching said preprogrammed length.
15. A method according to any of claims 10 to 14, wherein the speed of the motor (6) progressively increases during an initial step of the extension and/or retraction of said crutch (1).

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