An equipment having a means of this kind is known in the prior art from US-A- 6,095, 954 (=SE-C2-512765) with the same inventor and assignee as in the present application. The previously known means is provided with first and second weight magazines, which are capable of generating a variable tractive force in a first toothed belt to which, for example a handle might be connected for the application of a muscle force.

Said first toothed belt is loaded by the mass Ml of said first weight magazine and a second toothed belt is loaded by the mass M2 of said second weight magazine.

Additionally, said second toothed belt is connected to a pneumatic operating cylinder, which is controlled by means of an operating unit.

Said toothed belts are intermatable by means of a coupling means, which is formed as a lock yoke, and said operating cylinder can be made active in dependency of signals from said operating unit, which in turn responds to sensor signals depending on the actual position of the second weight magazine. Intermating the toothed belts alternatingly gives the possibilities of loading the first toothed belt by either the mass M1 or the total of the masses M1 and M2.

During the last five years the technical filed comprising drive units and regulating systems, which are electrically, electronically and/or digitally driven and controlled (pulse controlled) by means of optical sensors, has gone through a substantial development. This involves the fact that regulating units and associated electronic equipment now are less complicated and less costly than before at the same time as

the reliability has improved to a considerable extent and the interference sensitivity has decreased. Therefore, it is possible to use an uncomplicated conventional electric three-phase motor with a braking action for a drive unit, instead of the previously known equipment, which is both driven and controlled pneumatically.

The object of the invention is therefore to provide training equipment of the type mentioned in the introduction, which is less bulky than before, easier to handle and involve an increased security level. This is achieved with a means which has the characteristics stated in the following claim 1. Advantageous developments and improvements as well as an embodiment of the invention are evident from the dependent claims.

Said means according to the invention is also provided with a coupling means of the type mentioned by way of introduction, which however has been improved in that said coupling means is embodied by means of a slide block which is operable by means of an eccenter press and mounted in an auxiliary frame, which is stationary attachable to a training equipment.

The embodiment is described more closely in the following only as an example with reference to the accompanying schematic figures. According to the example the equipment is both driven and controlled by means of an uncomplicated three-phase motor with a braking action, which is controlled in dependency of processors and sensors of conventional type, the detailed construction of which therefore is not touched upon here.

Fig. 1 shows a vertical view of a means according to the invention for the generation of a variable tractive force in training equipment with two weight magazines which are connectable together, Fig. 2 is a view at a magnified scale of an eccenter press for a coupling means of the equipment,

Fig. 3 shows said coupling means of the equipment, operable by means of said eccenter press, Fig. 4 shows parts of the coupling means in an open state of the eccenter press, Fig. 5 shows said parts of the coupling means when the eccenter press is closing, Fig. 6 shows said parts with the eccenter press in its closed position.

The training equipment is constructed on a stand (not shown), on which a first weight magazine 2 with the mass M1 and a second weight magazine 4 with the mass M2 in the respective rest position VI, V2, rest in contact each against their own end position stop 6,8. Each magazine is connected to its own line, preferably a first 10 and a second 12 toothed belt, which run essentially vertically upwards from the respective magazine and which are deflected each by their own pair of pulley- wheels 14,16. From the pulley-wheels the outgoing parts 18 resp. 20 of the two toothed belts run essentially vertically downwards near to each other but without touching each other and are parallel. The toothed belts are mounted in such a way that the teeth on their outgoing parts are facing towards each other.

The outgoing part 18 of the first toothed belt is provided in the conventional way with a (not shown) fastener for an (equally not shown) external training equipment, e. g. handles, oars, levers, foot pedals, bars etc. Said toothed belt is in the unloaded state influenced by a force FO and in the loaded state by a muscle force F1 which overcomes the mass MI and consequently is able to lift the magazine 2 from the rest position VI to the work position Al. The (not shown) stand might be provided with an upper end position stop for each magazine (likewise not shown. If the muscle force diminishes in the direction towards FO so that it becomes less than the mass M1, the magazine 2 returns to its rest position V1.

A driving device 22 comprises a motor provided with a motor-brake 24, e. g. a three- phase motor 25, which via e. g. an electromagnetic toothed coupling 26 is connectable to the input of a reduction gear, e. g. a worm gear 27, which in turn is

provided with an output driving wheel 28. All of the components of the driving device are of a conventional kind, the detailed construction of which therefore is not touched upon here. Said motor-brake 24 is designed with a braking means which, e. g. by means of a spring force, is brought to the braking state and by means of a current supply is brought to its disengaged, not braking state. Said coupling 26 might be designed such, that it maintains its present coupling state on the occurrence of a cut off in the current supply and alters its coupling state on a re-establishment of the current supply only. The coupling 26 might also be designed such, that it always takes to its engaged state on the absence of current and its disengaged state on activated current supply. The outgoing part 20 of the second toothed belt 12 is in engagement with said output driving wheel 28 and might be either winded on or unwinded from said wheel depending on the present direction of rotation.

Said driving device 22 is activated by supplying a current to said motor-brake 24, said three-phase motor 25 and the electromagnetic toothed coupling 26 such, that the coupling 26 takes to or maintains its engaged state and the output driving wheel 28 of said worm gear 27 is rotated such, that the outgoing part 20 of the second toothed belt 12 is winded on said driving wheel 28.

Said driving device 22 is inactivated by cutting off the supply of current to the motor-brake 24, the three-phase motor 25 and the electromagnetic toothed coupling 26. In this state the driving wheel 28 is prevented from rotating due to the influence of the load of the mass M2, thanks to a braking force being exerted by the motor- brake 24 through the driving arrangement which includes the three-phase motor 25, the coupling 26 and the worm gear 27. Consequently, the fact that on the absence of current, the motor-brake 24 takes to its braking state and the coupling 26 its engaged state, it is secured that the second magazine 4 would not fall to the floor in case the supply of current is cut off.

Activating and inactivating of the driving device 22 might be controlled by means of an operating unit 29, which preferably consists of an electronic unit or digital central unit 29, which might be connected to a number of detecting devices or sensors, e. g. contact breakers, photo-electric cells, optical sensors etc. , which might have electrical, electronic or optical analogue/digital operating circuits. Advantageously, said central unit 29 might be arranged to response to sensor signals from e. g. conventional optical sensors, the influence of which will be described later, a starting switch 30 and a control panel, e. g. a display 31.

A first sensor 32 is located in association with the end position stop 6 of the first weight magazine 2 and arranged to emit a signal via a corresponding circuit line to the central unit 29, which signal indicates if the first weight magazine is in its rest position VI or not. A second sensor 34 is located in association with the lower end position stop 8 of the second weight magazine 4 and arranged to emit a signal via its corresponding circuit line to the central unit 29, which signal indicates if the second weight magazine is in its rest position V2 or not.

By activation of the driving device 22 it is possible to produce, in the outgoing part 20, a force F2 which overcomes the mass M2, which results in that the second magazine 4 is lifted from its rest position V2 to its work position A2 in association with a corresponding third sensor or end position sensor 36 attached to the stand (not shown). In this position the driving device 22 is inactivated, depending on the signals sent from said end position sensor 36 to the central unit 29, which results in that the magazine 4 is stopped and will remain in its work position A2. The magazine 4 will return to its rest position V2 only when the central unit receives a control commando to this course. For security reasons, to prevent the second magazine 4 to move past its work position, a fourth sensor or security sensor 38 is arranged, which is activated if for some reason the signals from the end position sensor 36 would fail to turn up. Consequently, in this case the driving device 22 instead would be inactivated by means of the auxiliary signals sent from said

security sensor 38 to the central unit 29. By these measures it is prevented that the magazine, which is possessed of a considerable kinetic energy during its movement from the rest position to the work position A2 and vice versa, neither in this case is causing any damage (goes through the roof).

The outgoing parts 18 respectively 20 of the toothed belts run through a coupling means 40, which is provided with an eccenter press 42 for operating, against the force of return springs 44, a slide block 46. Said side block is movably suspended in an auxiliary frame 48, which is stationary attachable to a training equipment and to which a support plate 50 is fixed. Said eccenter press 42 is in turn operated by means of a linear motor, e. g. an electromagnet 52 controlled by the central unit 29.

The eccenter press actuates said slide block 46 such, that a cam plate 54 mounted to the same, depending on the activating direction of said electromagnet 52, is movable between a first position and a second position in the auxiliary frame. Said cam plate 54 might take to its first position influenced by said return springs 44, provided the electromagnet 52 be activated such, that the eccenter press 42 is rotated counterclockwise to its open state (6). The cam plate 54 might take to its second position being displaced against the force of the return springs 44, provided the electromagnet 52 be activated such, that the eccenter press 42 is rotated clockwise to its closed state (s).

In its first position, the cam plate 54 is located on a predetermined distance (a) from said support plate 50, which distance (a) is sufficiently large to enable the toothed belts to run independent of each other in the gap which is delimited between the plates. When the electromagnet is activated the cam plate 54 is brought from its first position to its second position against the force of the return springs 44 by means of the eccenter press 42. In the second position the gap between the plates 54,50 is reduced to a"constriction"56, which corresponds to a predetermined space (b), through which the outgoing parts 18 respectively 20 of the toothed belts are compelled to pass and brought into contact with each other. Thus, the toothed belts

are mutually locked or hooked up to each other by means of the towards facing corresponding toothings.

In order to make the operation of said coupling means 40 reliable, it is important that the gap between the cam plate 54 and the support plate 50 is adjusted to the thickness of the toothed belts, which are to hand. Thus, in the present example the toothed belts 10,12 might have a thickness of 3-6 mm and the gap between the plates 54; 50 might vary between 6-15 mm. Advantageously, the thickness of each toothed belt 10, 12 might be given a value of 4,5 mm and the gap between the plates 54; 50 be allowed to vary between 7,5 and 13 mm. This means that the distance (a) is given the value of 13 mm and the space (b), or"constriction"56 is given the value of 7,5 mm.

A pulse wheel 58 of a conventional type is arranged to rotate in accordance with the pulley-wheel 14 shown to the left in the drawing. Fifth 60 and sixth 62 sensors arranged in association with said pulse wheel 58 might send signals to the central unit 29, which signals correspond to the direction of rotation of said left pulley- wheel 14 and indicate if the first magazine 2 is moving upwards or downwards.

When the first magazine is moving downwards and the present training equipment is moving towards the machine the pulse wheel 58 is rotating counter-clockwise.

The direction of rotation is sensed by the central unit 29, which activates the electromagnet 52 which, in this case strives to bring the slide block 46 to its second position in the auxiliary frame 48 and thereby to make the toothed belts hook up to each other by means of their corresponding toothings as they are pressed together by and between the cam plate 54 and the support plate 50.

A seventh sensor 64 is associated to the eccenter press 42 and arranged to send signals to the central unit as long as the eccenter press 42 is not in its closed state (s). This occur if the toothed belts are unable to hook up to the toothings of each other as a result of the belts are standing mutually tooth to tooth. Then, if the signals

are emitted for more than (t) seconds, the voltage/current to the electromagnet 52 will be reduced by 75 % by means of the central unit 29. Thanks to this even the clamping force, which is generated by means of the eccenter press 42 and urged by the plates 54; 50 to the toothed belts, will be reduced. A suitable value for (t) might be 0,185 seconds. The measure required for bringing the opposing toothings of the toothed belts slip into the corresponding spaces is just a slight displacement of the belts mutually, by varying the force F 1. When the belts thereafter have slipped into a mutually hooked up locking state, the electromagnet 52 is capable to rotate the eccenter press 42 clockwise even at a reduced voltage/current until said seventh sensor 64 influences the central unit to increase the voltage/current to 100 % and thereby complete the closing of the eccenter press 42. As soon as the eccenter press has taken to its closed state (s), as well as when it has taken to its open state (o), an eighth sensor 66, likewise co-operating with the eccenter press 42, influences the central unit such, that the power support to the electromagnet 52 will be cut off.

This is possible in that the eccenter press 42, in its open state (6) and closed state (s) as well, thanks to its geometry, for each state has a corresponding first and second contact surface/section 68 and 70 respectively in contact with the cam plate 54 and thereby is mechanically detained in the open state (6) and closed state (s) as well.

Therefore, the eccenter press 42 is shaped such that said first contact surface 68 makes an angle of 180°-a in relation to said second contact surface 70 and said a might attain values between 50-60°, preferably 55°. Said contact surfaces merge with each other in a rounded off apex 72. The eccenter press is suspended pivotally about a pivot axle 74 and the distance from said axle to the first contact surface 68 represents a length R1 and the distance to the second contact surface 70 a length R2.

By experimental work it has been shown advantageous that R1 is related to R2 as 3/4 and for the present embodiment suitable values might be chosen e. g. as follows: R1=16, 9 mm and R2=22, 5 mm. Essentially straight opposite to said apex 72, the eccenter press 42 is provided with a joint 76, which is articulated to the slewing bracket of the electromagnet 52. On each side of an imaginary line drawn from the

apex 72 to said joint 76, first and second activation surfaces 78 and 80 respectively are arranged, between the corresponding first and second contact surfaces 68,70 respectively and the joint 76. Said first activation surface 78 is dedicated to activate said eighth sensor 66 while said second activation surface 80 is dedicated to activate said seventh sensor 64. Advantageously, the joint 76 might be eccentrically displaced such that said imaginary line drawn from the same to the apex 72 does not intersect said pivot axle 74, but is displaced in a direction towards the second activation surface 80. Thus, in the open state (6) of the eccenter press 42, which is shown in Fig. 3 and Fig. 4, the cam plate 54, thanks to the influence from the return springs 44 and the attraction of gravity, is seated at the larger distance (a) from the support plate 50 and the toothed belts might run freely in the gap between the plates.

In the state shown in Fig. 5 the gap is decreasing to, in the closed state (s) which is shown in Fig. 6, finally have been reduced into the space (b), whereby the toothed belts hook into the toothings of each other. Thanks to the influence of the electromagnet 52 via the joint 76, in the closed state (s) the apex 72 has been displaced a distance (c) beyond (below) the pivot axle 74 of the eccenter press, whereby a mechanical locking is achieved, which overcomes the influence of the return springs 44 and the attraction of gravity as well. A suitable value for the distance (c) according to the embodiment might be set to approximately 3 mm.

Whenever applicable a ninth sensor 82 and a tenth sensor 84 respectively might be arranged in association with (not shown) protection devices, for example in the form of (likewise not shown) doors arranged in a protective casing for the respective first 2 and second 4 magazines, said doors preventing crushing injuries from occurring during training. These ninth and tenth sensors 82 and 84 respectively are arranged, via associated signal lines, to each supply a signal to the central unit 29 indicating whether the respective doors are closed or not.

As mentioned earlier, the central unit comprises known regulating means (processors) which, in dependence of the actual signals received via each of the

corresponding lines control the power supply to the driving device 22 in such a way that, for the current training situation, an optimal resistance is obtainable in the outgoing part 18 of the first toothed belt 10.

Operation The training equipment is placed in the ready state (B) for training by switching on the starting switch 30, which preferably might be embodied by an ignition lock and key. By means of each one corresponding button on the display 31, it is then possible to achieve a desired training effect by choosing between excentric fitness training (I) and concentric fitness training (II) in accordance with for the desired training effect representative sequences which will be described in closer detail later. Further, there is a button by means of which the equipment takes to its rest position (III).

Concentric operation Provided the starting switch is in its switched on state, the first sensor 32 supplies signals indicating, that the first magazine 2 is in the rest position VI and the display button (II) is operated, to the central unit 29, the latter controls the driving device 22 in such a way, that power is supplied to the motor-brake 24 and three-phase motor 25. By means of the toothed coupling 26 and the output driving wheel 28 of the worm gear 27, said wheel 28 being in engagement with the second toothed belt 12 which runs on the pair of pulley-wheels 16, the three-phase motor 25 then lifts the second weight magazine 4 from the rest position V2 to the working position A2.

When this position is reached the end position sensor 36, or whenever applicable, the security sensor 38 indicates this fact and supplies signals to the central unit 29 to cut off the power supply to the driving device 22. This result in the motor-brake 24 being activated into contact and the motor 25 stopped while the coupling 26 is maintained engaged. Thus, the second magazine 4 is kept in the working position A2 until another display button is operated. Simultaneously, the central unit 29 controls the coupling means 40 in such a way, that the slide block 46 takes to its

first position, which means the toothed belts might move independent of each other in the gap between the cam plate 54 and support plate 50. The equipment is now ready for use in concentric training.

Excentric operation Provided the starting switch is in its switched on state, the first sensor 32 supplies signals indicating, that the first magazine 2 is in the rest position V I and the display button (I) is operated, to the central unit 29, initially the same procedure is accomplished as above described to lift up the second magazine 4 from the rest position V2 to the working position A2 including keeping the magazine in the latter position. In case the second magazine 4 already is situated in its working position A2, the procedure is started from this position instead. The equipment is now ready for use in excentric training. By means of a (not shown) piece of external training equipment selected for the actual group of muscles, the muscle force F 1 is applied on the outgoing end 18 of the first toothed belt 10, which results in that the force F 1, via this toothed belt and the pulley-wheel 14, lifts the first magazine 2 from the rest position V 1 to the working position Al. The second magazine 4 remains in the working position A2 until another button is operated or the first magazine 2 is lowered by the user. This lowering will be indicated by the fifth 60 and sixth 62 sensors in that the pulse wheel 58, which is rotating together with the pulley-wheel 14, is rotating counter-clockwise. This in turn gives an influence to the control unit 29 to control the coupling means 40 and the coupling 26 such, that the cam plate 54 takes to its second position at the reduced space (b) relative to the support plate 50 and the coupling 26 takes to its disengaged state. Further, this means that the toothed belts are coupled together by means of their toothings, as compelled to pass through the gap between the plates 54; 50, which gap has been reduced to a "constriction"56, so long as the first magazine 2 coupled together with the second magazine 4 is lowered and said piece of training equipment is allowed to move in towards the machine.

When the first magazine 2 is lifted again by means of the piece of training equipment being pressed out from the machine, the pulse wheel 58 rotates clockwise, which is indicated by the fifth 60 and sixth 62 sensors, which influence the central unit 29 to control the coupling means 40 such, that the cam plate 54 takes to its first position at the distance (a) from the support plate 50. This means the toothed belts might move independent of each other in the gap between the cam plate 54 and the support plate 50, until the first magazine has reached its working position Al and is to be lowered once again. Simultaneously, the fifth 60 and sixth 62 sensors influence the central unit 29 to activate the driving device 22, whereby the second magazine 4 again is lifted to its working position A2 and when the first magazine 2 is lowered once more a repeated coupling together of the magazines takes place in a manner as described above.

Consequently, since the toothed belts are mutually hooked together, the mass MI and the mass M2 as well has an influence on the outgoing end 18 of the first toothed belt 10 and thus loads the actual group of muscles until both of the magazines has taken to their each rest position VI, V2. Then the first sensor 32 indicates once more to the control unit 29 that the first magazine is in the rest position V1, whereupon the central unit repeatedly activates the driving device 22, which acts for lifting the second magazine 4 to the working position and a new cycle has begun.

Rest position (OFF) When the display button (III) is operated the central unit 29 controls the driving device 22 in such a way, that electric power is supported to the motor-brake 24 and the three-phase motor 25 for a reversed rotation of the motor. By means of the toothed coupling 26 and the output driving wheel 28 of the worm gear 27, said wheel 28 being in engagement with the second toothed belt 12 which runs on the pair of pulley-wheels 16, the three-phase motor 25 then lowers the second weight magazine 4 from the working position A2 to the rest position V2. When this position is reached the second sensor 34 indicates this fact and supplies signals to

the central unit 29 to cut off the power supply to the driving device 22. This result in the motor-brake 24 being activated into contact and the motor 25 stopped while the coupling 26 is maintained engaged. Thus, the second magazine 4 is kept resting on its lower end position stop 8 in the rest position V2 until another display button is operated. Through the use of a three-phase motor 25 with a speed control, it is possible to control the second magazine as to the speed of lift and the speed of lowering as well by means of the central unit 29.

Each weight magazine contains as a rule a number of weights of conventional type, which can be mutually locked together mechanically as required. Automatic magazines with rapid selection available on the market can likewise be connected to the training equipment and facilitates in this case an accurate adjustment to the desired load in the different training phases.

It is also possible to produce a further adjustment of the load by arranging suitable gearing of the outgoing part 18 of the cable 10 by means of gearing with one or more extra pulley-wheels.

For the purpose of reducing the frictional resistance relative to the support plate and the cam plate the toothed belts might be coated by nylon fabric. The sliding surfaces of the support plate and the cam plate as well might be treated with Tuffrans, which result in a hard surface having a relatively low coefficient of friction.

According to the invention a reliable means for the generation of a variable tractive force in training equipment is advantageously achieved. Thus it is achievable after a completed training session to"drive"the second magazine down to its rest position and the motor-brake will be engaged in case the power supply is (accidentally) cut off. These facts prevent the second magazine to run through the floor/ceiling in its respective end position. The new design comprising an electromagnet, the length of stroke of which might amount to 20 mm only, yet will provide a larger total length of stroke and lesser dimensions than previously known means. By the fact that the coupling means is stationary mounted to the auxiliary frame, also a simpler interconnection of the used components is obtained.