EP0267071A1 - Apparatus for training, investigation and rehabilitation, especially of the myoneural function - Google Patents

Abstract

The apparatus comprises, in a stationary frame (100), a so-called "slaved isokinetic" work chain and a so-called "programmable dual-force drive chain", each comprising a drum (2, 73), a cable (1,1') which is wound on the drum and ends in a handle (27,27') to be gripped by the operator, and a return element (5,5') tending to wind the cable up on the drum. A motor (7) followed by a non-reversible reducing gear (8) is connected to the drums of the two chains by unidirectional transmission means (12, 72, 80) so as to exert or not to exert a force on the cable according to the direction and the speed of movement of the latter. <IMAGE>

Description

The invention relates to an apparatus for training, investigation and rehabilitation, in particular of the neuromuscular function.

French is known from Patent ^No. 2,558,378 a device of this type, including:

- a fixed frame;

- a working member intended to be connected to the subject to be exercised and which can move in a first direction and in a second direction opposite to the first;

- a return member connected to the working member to exert on it a force tending to move it in the first direction;

- a driving organ; and

- an irreversible transmission device capable of transmitting a force from the driving member to the working member in one of said directions, only when the speed of the working member counted algebraically in the second direction is not less than a threshold.

By irreversible transmission is meant here a transmission prohibiting the working member from influencing the movement of the driving member.

In this known device, the working member comprises a rotary drum on which is wound a rope secured to a gripping means by which the subject exerts on the rope a traction tending to unwind the drum. The drive member is a rotary engine, and the transmission device comprises an irreversible reduction gear and a unidirectional transmission element constituted by a free wheel mounted in such a way that its element integral with the drum cannot rotate faster in the direction corresponding to the unwinding of the rope as the integral part of the motor via the reducer.

As for the return member, it comprises an electromagnetic clutch mounted by means of a transmission between the rotary motor and the drum so as to be able to communicate to the latter a movement in the direction of the winding of the rope.

In this known device, when the subject does not exert traction on the rope, the latter is rewound by the movement of the motor transmitted to the drum by means of the clutch, the free wheel not opposing the movement drum in this direction. When the subject pulls on the rope at a speed such that the speed of rotation of the part of the free wheel integral with the drum remains lower than that of the other part, the subject must overcome a constant effort defined by the resistance of the clutch slipping. When the speed of unwinding of the rope reaches a value corresponding to the equality of the rotational speeds of the two parts of the freewheel, it engages and transmits to the reduction gear the force exerted by the subject. Because of its irreversibility, the reducer prohibits exceeding this speed of unwinding of the rope and opposes to the subject a resistant force equal to the force exerted by it.

The device which has just been described works satisfactorily but it cannot respond to certain operating cases necessitated by the evolution of methods of care or sports training.

In addition, a rational realization of the various functions fulfilled and the possibility of combining them simply and economically are desirable in order to widen its field of use.

The object of the invention is therefore to propose an apparatus the design of which allows both:

- the implementation of the functions of the known device;

- addition of additional functions;

- the separation into easily assembled or separable modular function groups.

The invention therefore takes up the two existing groups of functions:

- motor function: the rope is wound on the working pulley and pulls on the subject connected at its end; the recall effort is adjustable;

- resistant function: the rope takes place on the working pulley under the subject's traction, but beyond a certain speed (adjustable), the subject can no longer accelerate the movement. The traction speed regime is said to be "isokinetic". The more the subject pulls, the more the rope resists:
the resistant force is said to be "subject" to the force of which the operator is capable.

But it adds possibilities of rapid "rearming" of the system allowing repetitive efforts at high rate.

It also adds "muscle relaxation functions" by extending the muscle at high speed and low effort.

It also adds "safety functions" in muscle stretching, by automatically "disengaging" the main effort chain beyond a certain speed of retraction of the rope.

It allows automatic programming of the motor force according to the direction of movement of the rope.

It provides a number of technological means facilitating and extending the operation of the device.

It provides for several independent "work chains", usable separately or in combination and giving rise to a whole range of devices by a modular presentation of the groups of functions.

According to an embodiment of the invention, the device comprises two separate and independent "working chains". A work chain called "isokinetic controlled" and a work chain called "drive chain with double programmable force".

The "controlled isokinetic" work chain essentially comprises:

- a rotary drum on which is wound a rope secured to a gripping means;

- a rotary motor driving an irreversible reducer, in particular of the worm type, on the axis of which is mounted a unidirectional transmission element, in particular a freewheel, mounted so as to secure the rotary drum to the irreversible reducer if the speed of rotation communicated to the rotary drum by the operator tends to exceed the speed chosen for the gear unit output shaft;

- a return member comprising a spiral spring resting at one of its ends on a fixed point secured to the frame and driving at its other end the rotary drum either directly or via a pulley whose diameter varies along its axis and pulling a cable winding on the pulley and one end of which is attached to the drum. This return member generates a permanent pulling force on the rope, generally adjusted to produce a low pulling force but a high speed of retraction of the rope if the operator releases its pulling force.

The assembly constituted by this isokinetic working chain then allows exercises with a "concentric" effort (direction of traction of the rope) proportional to those of the operator and at a limited speed, and an "eccentric" effort (direction of relaxation of the rope) at low effort and high speed. The concentric and eccentric exercises can be repeated at a high rate, regulated by the choice of the speed limit in concentric movement.

This chain can be doubled from a reducer with two outputs and allow to actuate two members simultaneously and symmetrically or two members in alternating movement, or allow the training of two operators simultaneously.

The "drive chain with double programmable force" essentially comprises:
- A rotary drum on which is wound a rope secured to a gripping means to which the operator is connected;
- A power motor assembly, called "low speed", comprising a motor, a transmission (or a reduction gear) the output axis of which is integral with the driving element of an effort coupler with adjustable torque, remotely controllable and advantageously independent of the sliding speed (for example an electromagnetic clutch powder). The driven element of the force coupler is connected via a unidirectional transmission element (for example a freewheel) to the rotary drum.

Adjusting the force of the force coupler makes it possible to adjust the tensile force exerted on the rope when it is wound on the rotary drum. As long as the speed of the rope is lower than the speed which results from the speed communicated by the gearmotor to the drum via the force coupler, this force remains identical if the rope unwinds or winds up to this speed. limit. Beyond this winding speed limits the free wheel disengaged and the rotary drum is no longer subjected to the force of the auxiliary drive member or return member.

- An auxiliary motor member, constituted as the return member of the isokinetic working chain described above and whose spiral spring tends to produce a tensile force winding the rope at low effort but high speed, the rotary drum released from the action of the low speed effort coupler by disengaging the freewheel allowing the operator to relax his effort either to protect him from too great an effort of muscular elongation in an area of less physiological resistance, or to allow a muscle relaxation phase under low effort, or simply to activate the rearming phase of the device allowing the distribution of the muscle contraction movement.

- A device for detecting the direction of rotation of the rope consisting of a friction washer driven by the working member and driving a friction plate kept in rotation between two stops, at least one of which is equipped with a finger acting on a microswitch which acts on the selection of the force transmitted by the low speed force coupler (and in particular on the supply current in the electromagnetic powder clutch) to differentiate the force produced when the rope is unwound (muscle contraction) or when it is wound (muscle elongation).

Of course, the two motor / reducer assemblies included in the two working chains can be distinct, but the use of a single geared motor is made technically possible because the two chains each operate at their own pace and neither imposes its own pace on the other.

Similarly, the two chains can be used successively by the operator for exercises of a different nature; they can thus be used to activate different physical parts of the same operator or to simultaneously train two operators.

But they can also be connected, the rope of the second chain coming to connect on the rope of the first chain upstream of the gripping member of the rope of the first chain, a return system allowing the two ropes to come out of the frame support enclosing the mechanism by a single "window", each rope having its own stop to limit its reentry stroke.

Note the following advantages related to the use of this device when the two cables are connected.

The operator is then subject to the superposition of the efforts of the two ropes: he can execute a concentric traction effort (muscle contraction) under adjusted effort up to the isokinetic speed limit, then an isokinetic enslaved effort, then release the rope and perform an eccentric movement (lengthening of the muscle) under a different effort, then quickly release the rope under weak muscular effort.

Two important remarks can also be made:

- Using the same irreversible gearmotor to power the two work chains obviously brings savings, but it is also a safety factor. Indeed, the speeds of the rope during isokinetic (N₀) and eccentric (KN₀) concentric exercises are related to each other by the ratio of the diameters of the working drums. It follows that if the choice of the speed of isokinetic exercises is low, that of the eccentric movement under strong effort is also low, the rhythm of the alternating exercise is respected.

- If the gearmotor is stopped, the movement of the rope of the first chain is prohibited, an operator can then be subjected to a "static" traction exercise of high level of effort.

On the other hand, the use of the rope of the second chain meets only the resistance of the force coupler, then operating as a brake. The pulling movement of the rope under muscular contraction can be adjusted according to the exercise, but the retraction of the rope under muscular stretching only depends on the effort of the auxiliary organ (low effort, high speed) allowing significant relaxation without contribution of external energy. This achieves the functions of a simplified drive device that the module of the second working chain can provide inexpensively on a fixed axis replacing the gearmotor.

A simplified device according to the invention can comprise only the first or only the second of the chains described above. Such an apparatus has the characteristics indicated in the introduction, the return member being entirely separate from the drive member and the transmission device.

In the first chain described, the device for transmitting sion transmits a force in the second direction, and this force is transmitted when the working member moves in the second direction at a speed which is not less than the threshold in absolute value.

In the second chain, the transmission device transmits a force in the first direction and this force is transmitted when the working member moves in the second direction at any speed or moves in the first direction at a speed which does not is not greater than the threshold in absolute value, this threshold being negative in this case.

The apparatus according to the invention can also comprise two isokinetic chains, intended to be used jointly or separately by the same operator or by different operators. In particular, these two chains can be associated with two pulleys secured to the same axis, located inside or outside the fixed frame of the device, the output ropes of the two chains being wound respectively on the two pulleys in opposite directions. The axis is then subjected to a zero restoring torque as long as its rotational movement takes place between two speed thresholds imposed respectively by the two chains, one in a direction of rotation and the other in the opposite direction. Any torsional effort made by an operator on this axis at a speed at least equal to the threshold corresponding to the direction of rotation encounters resistance equal to the effort made by the operator, and the rotational speed cannot exceed this threshold.

According to another characteristic of the invention, the apparatus comprises means for varying the isokinetic speed threshold and / or the limit speed of effect of the eccentric force. To this end, the rotary motor can be of variable speed, constituted for example by a continuous or alternating motor whose speed is regulated by a suitable electronic device; it is also possible, in simpler versions, to use an alternating motor with double winding and two speeds.

It is possible to widen the possibilities of using the device by providing means for measuring the speed of movement of the working member, of the movement carried out by the latter during an exercise and / or the effort. exercised by the subject on the working organ. It is also possible to provide signaling and / or counting means which are excited when a quantity thus measured reaches a determined value, and / or means for displaying the value of a quantity measured as a function of time or as a function of another measured quantity.

Advantageously, the frame of the device comprises a rope exit window comprising two pairs of parallel cylinders, these two pairs being oriented perpendicular to one another.

The invention also provides for making the frame integral with a frame supporting a plate on which the subject can be placed when using the device.

• - la figure 1 est une représentation schématique des éléments mécaniques d'un appareil selon l'invention;
• - la figure 2 est un schéma électrique d'un dispositif électronique de variation de vitesse du moteur utilisable dans l'appareil;
• - la figure 3 est un schéma d'un dispositif de signalisation et d'affichage de l'amplitude du mouvement exécuté au cours d'un exercice;
• - les figures 4 à 6 représentent schématiquement des dispositifs de mesure de l'effort exercé par l'opérateur;
• - la figure 7 représente schématiquement une possibilité de montage des éléments mécaniques dans le bâti de l'appareil;
• - les figures 8 et 9 représentent des détails de réalisation de la fenêtre de guidage pour la sortie du filin de travail;
• - les figures 10 et 11 sont des vues respectivement en élévation et de dessus d'un châssis prévu pour supporter l'appareil et l'opérateur.

Other characteristics of the invention will emerge from the detailed description below and from the appended drawings in which:

• - Figure 1 is a schematic representation of the mechanical elements of an apparatus according to the invention;
• - Figure 2 is an electrical diagram of an electronic device for varying the speed of the motor usable in the device;
• - Figure 3 is a diagram of a device for signaling and displaying the amplitude of the movement executed during an exercise;
• - Figures 4 to 6 schematically represent devices for measuring the force exerted by the operator;
• - Figure 7 shows schematically a possibility of mounting the mechanical elements in the frame of the device;
• - Figures 8 and 9 show details of the embodiment of the guide window for the exit of the working rope;
• - Figures 10 and 11 are views respectively in elevation and from above of a frame provided to support the device and the operator.

To limit the number of figures, we have sometimes shown on the same figure different elements playing the same role and which in principle are not present on the same device.

This device comprises a frame 100 shown by a simple closed line inside which a drum 2 is mounted integral with the outer ring 12b of a freewheel 12. The internal element 12a of the latter is mounted integral with a shaft outlet 11 of a reduction gear 8 of the worm and tangent wheel type, with a high and irreversible ratio. The wheel 10 of the reducer is driven by an endless screw 9 mounted on the shaft of the rotary motor 7.

The rotary drum 2 has a wide groove 2a on which is wound the rope 1 which crosses the wall of the frame and ends outside of the latter by a grip handle 27.

A set of rollers 97 and 98 optionally makes it possible to guide the rope 1 inside the frame towards an outlet window 59 which will be described later.

The rotary drum 2 also has a narrower groove 2b in which is attached one end of a cable 4, by a screw or by any other rapid fixing means. The other end of the cable 4 is attached in the groove of a pulley 5a, the diameter of which can advantageously vary along the axis to ensure speed correction. Pulley 5a is connected to the outer end of a spiral spring 5c, the other end of which is linked to a fixed shaft 5b around which the cable is wound. By its direction of winding around the shaft 5b, the spring tends to rotate the pulley 5a and the drum 2 so as to wind the rope 1 on the drum 2. A button 5d makes it possible to vary the tension of the spiral spring by modifying its fixing relative to the fixed point of the shaft 5b.

The spring assembly 5 formed of elements 5a, 5b, 5c, 5d, could be mounted at the end of the drum 2 in a simplified device, thus eliminating the cable 4 and the groove 2b, and excluding the possibility of adjusting the forces and the speeds. This set is for example constituted by a device of the AEROMOTIVE type marketed by the firm REELS.

The assembly described so far constitutes the first work chain called "isokinetic controlled". When the motor is running, driving the shaft 11 of the gearmotor at a speed W _O in the opposite direction to that in which the return spring acts on the cable 4, the rope 1 can move under the action of the operator being subjected only to the force of the spring 5c, transmitted in a ratio defined by the diameters of the pulleys 5a, 2b and 2a.

If the speed N of the rope which takes place tends to exceed the speed N₀ corresponding to W₀, the freewheel 12 is blocked and secures the drum 2 on the shaft 11 whose speed is irreversibly limited. If the operator slows down or even releases the rope, the rope rewinds under the effect of the spiral spring and resets the device for the next exercise.

We will now describe the second work chain called "drive chain with double programmable effect". On the second shaft 11b of the gearmotor is mounted a force coupler 80 such as an electromagnetic powder clutch MEROBEL type CT350. The interior 81 of the clutch is keyed to the shaft 11b and supports by bearings 82 an inductor driven element 83 carrying a winding 84 which creates a coupling in the powder contained in the air gap 85 between the elements 81 and 84. This force depends on the direct electric current supplied to the coil 84 by the sliding contacts 86 to which an adjustable direct current generator 87 is connected. This makes it possible to vary the torque transmitted between the elements 81 and 84.

A plate 88 secured to the inductor 83 supports the inner ring 70 of a free wheel 71, the outer ring 72 of which is rigidly connected to a pulley 73 provided with two grooves 73a and 73b. In the groove 73b is fixed one end of a rope 1ʹ whose other end is connected to a gripping means 27ʹ outside of the frame 100 and which is returned on casters 95 and 96 so as to rub shoulders with the rope 1 in the same outlet window 59. The groove 73a receives a cable 4ʹ connected to a spring assembly 5ʹ similar to the assembly 5 and tending to rotate the pulley 73 in the direction of winding of the rope 1ʹ.

A friction washer 74 secured to the pulley 73 drives a disc 75 provided with a lug 76 which cooperates with a fixed stop 77 to cause the closing of a microswitch 78 acting on the input of the electric generator 87 when the rope 1ʹ s 'wound on the drum 73.

The freewheel 71 allows the coupling of the drum pulley 73 to the reduction gear as long as the rope 1ʹ takes place under the effect of the traction of the operator exerted on the force handle 27ʹ. It also allows this coupling if the operator lets the rope wind at a speed lower than that produced by the coupler connected to the axis 11b. On the other hand, the freewheel disengages if the rope 1ʹ winds up at a higher speed. It is then driven only by the cable 4ʹ under the effect of the spring assembly 5ʹ.

The effort chain acting on the rope 1ʹ therefore produces a constant but adjustable effort adjusted in the clutch 80 by the current of generator 87, as long as the speed of the rope 1ʹ is negative (the operator pulls) or as long as this speed is positive (the operator releases) but less than a threshold speed KN₀ proportional to the threshold N₀ of the first working chain. Beyond this speed, the rope is brought back at high speed and low effort by the device 5.

When the rope 1ʹ is unwound, the microswitch 78 is open and controls a force in the force coupler 80 at a value called "concentric force".

When the rope 1ʹ is wound, the microswitch 78 is closed and controls a force in the force coupler 80 at a value called "eccentric force".

Each of these two efforts can be adjusted independently.

It will be noted that the generator can be subjected to a value adjustment depending on other parameters, such as the position of the rope which can be identified by a potentiometer 22 linked to one of the working drums 2 and 73.

The two ropes 1 and 1ʹ can be connected to the same force handle 27. Stops 26 and 26ʹ tightened on the ropes 1 and 1ʹ lock on the window 59 and provide mechanical protection for the operator.

The description which follows relates to various alternative embodiments of the motor 7 and of its supply.

In the example shown in Figure 1, the limit speed of unwinding of the rope is unequivocally linked to the speed of the motor. To make a device as economical as possible, a single-phase electric motor of the current type is used providing a single speed limit.

Two speed limits can be obtained by using a single-phase 50/60 Hz double-coil motor, for example a 2-pole-4 pole industrial motor, providing a speed ratio of 1 to 2, or better still a 2-pole-12 pole motor. , conventionally used in washing machines, providing a ratio of 1 to 6.

Under these conditions, the lowest motor speed can be used for bodybuilding exercises involving a low speed and often reduced rope elongation but considerable effort (pelvis, thorax, legs or arms alone), while speed the higher is suitable for high-speed muscular exercises and / or great elongation of the rope with reduced efforts (ensemble exercises where almost the whole body contributes to the speed and the amplitude of the movement).

When the safety rules prohibit a high voltage supply (edges of swimming pools, runoff), one can use a continuous low voltage 12 volt or 24 volt motor similar to car starter motors. If necessary, switching under 12 volts or 24 volts allows two limit unwinding speeds to be obtained.

In professional devices, for example rehabilitation devices, it may be useful to have a continuous and extensive range of speeds, allowing for example to practice the same type of training at a progressively increasing speed, the patient's progress manifesting by carrying out the same movement with a constant effort but an increasingly high speed. To this end, an adjustable speed motor can be used, for example an alternating frequency variation motor associated with a known frequency converter, or a direct current motor associated with an electronic control device such as that shown in the figure. 2.

The device of Figure 2 allows to vary the speed of a DC motor whose field is produced in the stator by permanent magnets and whose armature is supplied from the single-phase sector 220 volts 50/60 Hz, and is distinguished from similar devices known by galvanic decoupling elements of opto-electronic type improving the safety of handling.

A rectifier block 101 supplied from the 220 volt 50 Hz sector comprises, connected in bridge across the sector, two thyristors 101a and 101b associated with two rectifiers 102a and 102b. The armature 103 of the motor to be supplied is connected in series with a shunt 104 at the output terminals of the bridge, the measurement shunt 104 thus being traversed by the current from the armature.

The rectified voltage present at the terminals of the shunt, after amplification by an amplifier 105, drives an opto-electronic block 106 comprising a photo-transistor 106a controlling an output transistor 106b so as to develop a voltage across the terminals of an output resistance 107 isolated and low level constituting a signal representative of the engine speed. This signal is transmitted to a measuring instrument 107a which may be a galvanometer or a preamplifier for a recorder or a cathode oscillograph.

The speed signal also attacks the input of a regulating block 108, in which it is compared with the signal coming from an regulating block 109 serving to select the desired speed. A difference signal produced by the block 108 is sent, via an isolation transformer 110, to the thyristor control electrodes 101a and 101b.

The regulating block 108 and the regulating block 109 are supplied by a direct voltage of the order of 12 volts developed from the 220 volt 50 Hz sector by means of a transformer 111 and a rectifier bridge 112.

Finally, a compensation loop galvanically decoupled by an opto-electronic assembly 113 with photo-transistor and output transistor connects the control block 108 to an auxiliary winding 110a of the control transformer 110 to modify the shape of the input signal in the purpose of ensuring good stability of the engine speed at very low revs.

The adjustment block 109 may include a manual adjustment potentiometer 109a supplied at its fixed terminals by the low direct voltage coming from the rectifier bridge 112, one of these fixed terminals and the variable terminal connected to the cursor producing an adjustable low voltage which is sent as reference voltage to the input of regulation block 108. This is a conventional manual control. There is also shown a second adjustment potentiometer 109b mounted in cascade and making it possible to vary the speed of the motor, for a given position of the cursor of the potentiometer 109a, as a function of a chosen parameter, for example the position of the drum 2, or still time, using a timer.

One can also provide a current ramp generator or a signal generator of variable shape adapted to the exercise. Such a generator, indicated at 109c in FIG. 2, can, thanks to switching, replace the manual adjustment block 109.

.A simple two-speed device can exclusively use two isokinetic chains. For example, two freewheels can be mounted respectively at the two ends of the gearbox output shaft, a first drum of radius Ra being mounted directly on the outside of the first freewheel and a second drum of larger radius Rb being connected to the second freewheel by a system of pulleys and belt ensuring a multiplication ratio P. On the first drum is wound a low speed rope and on the second drum a high speed rope, the ratio limit speeds of unwinding of the two ropes being equal to

.

Each of the two ropes can be associated with its own spiral spring return member as illustrated in FIG. 1. Alternatively, the cable winding on the pulley of variable diameter of a single return device can end in a caster acting on a second cable, the two ends of which are wound respectively on the two working drums, allowing an action independent of the return member on the two working members.

An assembly similar to that which has just been described, but symmetrical and leading to identical limit speeds for the two ropes, can be used to obtain symmetrical alternating forces on the two members.

When you don't have a source of electricity, you can replace the electric motor with a heat engine.

Knowledge of the speed limit of unwinding constitutes a fundamental datum of the training carried out by means of the apparatus according to the invention.

In the case of a continuous variation of the motor speed, it is possible to have recourse to this for locating the positions of the control potentiometer.

A more elaborate solution consists in displaying an analog or digital indication provided by a measurement of the control voltage of the motor regulation. One can for example use a conventional digital display device comprising three displays with seven segments each associated with a pulse counting cell and a decoding block. The counting block associated with the first display counts the pulses supplied by a generator from the analog measurement signal. A clock block allows counting for a given time and resetting. Each of the other counting cells is connected to the previous one and to the clock block. Each decoding block is connected to the corresponding display by seven resistors.

The speed display can also be achieved by a light ramp formed for example by diodes powered respectively by amplifiers which compare the analog measurement signal to different fractions of a reference voltage defined by a chain of resistors.

The rope run is another exercise control parameter. We can identify the angle of rotation of the working drum 2 on which the rope 1 is wound, for example using a multi-turn potentiometer 22 secured to the drum (Figure 1) and whose output voltage depends on the number of laps completed, the zero adjustment can be operated by a button 23 acting on the body of the potentiometer. The latter can be replaced by a pulse sensor associated with a toothed disc or with an impression of light and dark zones on the drum, the pulse sensor being constituted in the latter case by an optical cell counting the light and dark zones. .

The indirect measurement of the displacement of the rope by the rotation of the drum introduces an error due to the overlapping of the turns on the drum. Direct measurement is preferable if high precision is desired. A device proposed for this purpose comprises an echo sounder transceiver fixed to the frame 100 at the level of the exit of the rope oriented by means of a toggle so as to emit a beam of ultrasound in the direction of the fastener 27. The latter carries a shield which ensures the reflection of ultrasound. The receiver produces an analog signal representing the distance between the wall of the frame and the member linked to the rope.

FIG. 3 shows an example of a circuit for processing the measurement of the unwinding of the rope. A first potentiometer 301 supplied by the measurement signal supplies a voltage representing the extension of the movement carried out, while another potentiometer 302 connected to a DC voltage source supplies a voltage representing the extension of the rope to be produced during an exercise. When the difference between these two voltages becomes less than a threshold, a relay 303 supplies one or more indicating devices such as an indicator light 304, a buzzer 305 and / or a counter for exercises accomplished 306. In addition, the voltages supplied by the potentiometers are sent to a display device 307 such as a cathode oscilloscope with two remanence channels. The horizontal scanning of the oscilloscope can be subjected to a voltage increasing linearly in time provided by a time base 308, so as to produce a diagram representing the length unwound as a function of time, or of a voltage as a function increasing from l 'force exerted by the operator, supplied by an amplifier 309 connected to a force sensor 310, leading to the visualization of the length of rope as a function of the force exerted. In both cases, a horizontal line represents the reference voltage and makes it possible to determine when or for what effort the length set as a target is reached. Optionally, a voltage generator 311 which supplies a voltage representing a theoretical effort to be made and connected to the oscilloscope 307 allows the display of a diagram indicating for which elongation the theoretical effort is made.

The force exerted on the rope by the operator can, in turn, be determined by different means. A particularly simple means is illustrated in FIG. 4 which schematically represents certain elements of a variant of the device. The rope 1 unwinding from the drum 2, similar to that of FIG e 1, and shown here in axial view, is deflected by a roller 30 connected to a force sensor 31 secured to the frame 100 before leaving the frame between two guide rollers 32. The opposite reaction force the operator's effort is then proportional to the effort measured by the sensor 31, to the friction near the rope on the rollers 32. Of course, the axis of the caster 30 is placed so that the strand 34 of the rope between the drum and the caster and the strand 33 between the latter and the rollers 32 are symmetrical with respect to the direction of the force transmitted to the sensor 31. The proportionality coefficient depends on the angle between the strands 33 and 34, and is equal to 1 when these strands are parallel, as shown.

In an isokinetic device it is advisable to avoid the use of a force sensor having large deformations under force, for example a load cell with spiral spring, which would introduce a disturbance in the stroke of the rope. It is preferable to use a very slightly deformable sensor, comprising for example a strain gauge bridge 31b whose microdeformations under stress induce an electrical imbalance voltage at the output terminals of the bridge when a low electrical voltage is sent to the input by a generator 35. The imbalance voltage is amplified and collected in a measuring device 36 comprising an analog output and capable of ensuring the control of a threshold relay and the various functions described above for the signal processing (visual or audible signaling, counting and / or recording of the analog signal).

However, if it is desired to use only the information that a certain effort threshold has been exceeded, the sensor 31 can be constituted by a slightly deformable mechanical load cell which, for a given deformation, closes an electrical contact to trigger a signaling appropriate.

A variant of the force measurement device is shown in FIG. 5. A pulley 42, on which the rope 1 is deflected, here again forming two strands 43 and 44 arranged symmetrically leading respectively to the drum 2 and to the output guide rollers 59 , compresses a deformable element 41. The latter comprises a spring 41a working in compression and a rod 41b linked to the movable end of the spring and one end of which carries a magnetic element 41c. The latter acts on a magnetic relay 45 of ILS type whose position is adjustable in height by a screw 46. The contact of the relay is established for a given compression of the spring 41a corresponding to a determined force of the operator. The sensor 41 which has just been described can be replaced by the weighing system of a scale of the bathroom scale type, the weighing of which is transmitted remotely by an infrared system, decoded and displayed on a screen.

The force measurement devices described so far provide a result tainted by errors due to friction. This drawback can be eliminated by the device illustrated in FIG. 6, in which the fastener 60 which connects the end of the rope 1 to the operator is equipped with a flat deformable capsule 62, sensitive to the tensile force or compression exerted between the fastener and the operator and on which is stuck a measuring device 63 based on strain gauges conventionally mounted in bridge. The bridge can be powered by a miniature battery 64 associated with a contact 65 sensitive to compression, which closes as soon as the operator works, thus preventing the battery from discharging when the device is at rest. The battery and the sensitive contact can be incorporated into the clip 60.

The unbalance signal of the bridge can be routed to the frame 100 by an electrical conductor 67 with two or three strands winding on a winch 69 actuated by a motor element 68 similar to that provided for the rewinding of the rope 1. The input of conductor 67 in the frame is done by a guide window 70 adjacent to the guide window 59 of the rope, so as to limit both the incidence of the conductor 67 on the reaction force transmitted by the rope 1 to the operator and the risk of tangling of the conductor and rope.

The transmission of the measurement signal by a conductor 67 can be replaced by the transmission of radiation by a transmitter secured to the clip 60, for example in the form of a pulse signal whose emission frequency is fixed and whose l amplitude is proportional to the analog signal of unbalance voltage of the bridge 63. A receiver housed in a measurement box 66 transforms the signal from the transmitter 71 into an analog signal. Of course, it is also possible to connect the fastener 60 to the box 66 by an electrical conductor, or to house in the frame 100 the receiver associated with the transmitter 71.

The means for measuring displacements and forces have been described above in conjunction with the isokinetic working chain, for which they are more particularly advantageous. However, they can also be used with a double-acting drive chain, or in conjunction with these two types of chain.

The frame 100 of the apparatus may have a parallelepiped shape and be made from welded tubes 400 (FIG. 7) forming a rigid frame and on which are fixed the support elements guiding the traction rope and the auxiliary elements of support or hauling which the operator may need to provide his effort. This frame also includes wall fixing elements or fasteners for fixing on a pillar, a gantry or any other support capable of withstanding the forces.

The mechanical elements comprising in particular the working member 2, the motor element 5 and the resistant assembly are advantageously mounted on a plate 401 fixed to the chassis 400 by means of damping elements 402, for example of the silent block type, so as to reduce the vibrations and the noises produced by the mechanics in motion (see FIG. 7). The guide window 59 for the exit of the rope must be able to withstand significant forces by introducing as little friction as possible. As illustrated in FIG. 8, it is preferably formed by two pairs of cylinders, a pair of cylinders 403 with parallel axes and a pair of cylinders 404 with axes parallel to each other and perpendicular to those of cylinders 403, the four cylinders swiveling on bearings 405 supported by a plate 406. Where appropriate, several such windows are provided, one for each rope to be guided.

Still in order to limit friction, it is desirable that the guide window 59 be placed so as to limit the angular deviation of the rope as it passes. For this purpose, it is advantageous that the position of the plate 406 on the chassis is adjustable. Thus, the plate 406 can be slidably mounted on slides integral with the tubular frame, placed on the front face for a front tensile force or on the upper face for a vertical tensile force, a rapid clamping device making it possible to immobilize the plate 406. The plate can also be supported by a rotary assembly comprising two arms 408 linked to an axis 409 by a bearing 410, the axis 409 being integral with the tubular frame 400 or the plate 401 (FIG. 9). A lever 411 makes it possible to immobilize the bearing 410 in a position corresponding to the direction of traction of the rope.

The faces of the device may be constituted by removable elements such as metal or plastic plates comprising decorative elements and the marks of the adjustment or measuring devices, and possibly supporting on their internal face certain measuring elements. These plates can also be coated with noise absorbing materials.

FIGS. 10 and 11 show an additional tubular chassis 412 on which the frame 100 of the device can be fixed by means of feet 411 fixed on the tubular chassis 400. Casters 413 make it possible to transport the assembly more easily. On the chassis 412 is fixed a support plate 414 on which the operator can mount, ensuring by its own weight and by the reaction force exerted on it by the device the immobilization thereof regardless of the efforts that it develops by pulling on the rope 1. On the plate 414 one can mount any directional return of the rope required by the movement, and also any force measurement equipment, in particular those of FIG. 6. In particular, the rope 1 leaving the guide window 59 can be supported on a roller 415 carried by a non-deformable frame 416 pivoting about an axis 417 secured to the plate 414 and supported by a roller 418 in the center of the platform of a rocker 419 which records a component of the tensile force exerted by the operator on the rope.

Claims (21)

1.- Training, investigation and rehabilitation apparatus, in particular of the muscular-muscular function, comprising:

- a fixed frame (100);

- a working member (2) intended to be connected to the subject to be exercised and able to move in a first direction and in a second direction opposite to the first;

- a return member (5c) connected to the working member to exert on it a force tending to move it in the first direction;

- a drive member (7); and

- an irreversible transmission device (8,12) capable of transmitting from the driving member to the working member a force in one of said directions, only when the speed of the working member counted algebraically in the second direction is not less than a threshold;
characterized in that the return member is entirely separate from the drive member and the transmission device. 2.- Apparatus according to claim 1, characterized in that the working member comprises a rotary drum (2) on which is wound a rope (1) secured to a gripping means (27). 3.- Apparatus according to claim 2, characterized in that the return member comprises a spiral spring (5c) driving a cable (4), one end of which is attached to the drum. 4.- Apparatus according to claim 3, characterized in that the cable (4) is wound on a pulley (5a) whose dia meter varies along its axis. 5.- Apparatus according to one of the preceding claims, characterized in that the motor member is a rotary motor (7) and that the transmission device comprises an irreversible reduction gear (8) and a unidirectional transmission element (12). 6.- Apparatus according to claim 5, characterized in that the reducer is of the worm type. 7.- Apparatus according to one of the preceding claims, characterized in that the transmission device is capable of transmitting a force to the working member in the second direction. 8.- Apparatus according to one of claims 1 to 6, characterized in that the transmission device is adapted to transmit a force to the working member in the first direction. 9.- Apparatus according to claim 8, characterized in that the transmission device comprises a force coupler (80) whose transmitted torque is adjustable. 10.- Apparatus according to claim 9, characterized in that means (77,78) are provided for varying the torque transmitted by the force coupler according to the direction of movement of the working member. 11.- Apparatus according to one of the preceding claims, characterized in that it comprises in the same frame (100) two working members (2.73) associated with respective return members (5c, 5ʹ) and a same driving member (7) by respective transmission devices, one of the transmission devices was as defined in claim 7 and the other being as defined in one of claims 8 to 10. 12.- Apparatus according to claim 11, characterized in that the transmission devices comprise a common reducer (8) and separate unidirectional transmission elements (12,71). 13.- Apparatus according to one of claims 11 and 12, characterized in that the two working members are linked together so that a movement of the subject to be exercised is accompanied by a joint movement of these in the first or second sense. 14.- Apparatus according to one of the preceding claims, characterized in that it comprises means for varying said speed threshold. 15.- Apparatus according to one of the preceding claims, characterized in that it comprises means for displaying said speed threshold of the working member. 16.- Apparatus according to one of the preceding claims, characterized in that it comprises means (22,25) for measuring the movement made by the working member during an exercise. 17.- Apparatus according to one of the preceding claims, characterized in that it comprises means (31,41,58) for measuring the force exerted by the subject on the working member. 18.- Apparatus according to one of claims 15 to 17, characterized in that it comprises signaling and / or counting means (304,305,306) which are excited when a measured quantity reaches a determined value. 19.- Apparatus according to one of claims 15 to 18, characterized in that it comprises display means (307) of the value of a quantity measured as a function of time or as a function of another measured quantity . 20.- Apparatus according to one of the preceding claims, characterized in that the frame comprises an outlet window (59) of the rope comprising two pairs of parallel cylinders (403,404) oriented perpendicular to each other. 21.- Apparatus according to one of the preceding claims, characterized in that the frame is integral with a frame (412) supporting a plate (414) on which the subject can be placed when using the device.

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