WO1996009854A1

WO1996009854A1 - A weight lifting apparatus

Info

Publication number: WO1996009854A1
Application number: PCT/IE1995/000050
Authority: WO
Inventors: Eugene Long
Original assignee: Eugene Long
Priority date: 1994-09-28
Filing date: 1995-09-28
Publication date: 1996-04-04
Also published as: AU3576595A

Abstract

A weight lifting apparatus (1) of the free type allows a user to lift a barbell and to release it at any stage safe in the knowledge that it will not drop by any appreciable amount. The user presses against a handle on the barbell to keep a lock released and immediately when he stops pressing the handle, the lock moves to its default, locked state and the barbell is suspended. Guide spools (15) are used to gather the belts (11) under the action of a counter-weight bracket (18). The barbell is suspended by ratchet and pawl mechanism locks which prevent the spools (15) from rotating.

Description

"A weight lifting apparatus"

The invention relates to a weight lifting apparatus of the "free" type and comprising a support frame, flexible links for connection to a barbell, a guide means for maintaining the links taut during lifting of the barbell, and a lock for the guide means.

Such an apparatus is described in Canadian Patent Specification No. CA 2023385 (Webber) . In this apparatus, the flexible links are belts which are connected to counter-weights which maintain the belts taut. The lock comprises stop pins which extend through vertical frame members and limit upward movement of the counter-weight and therefore downward movement of the barbell so that it is suspended at a pre-determined position.

Traditionally, free weight lifting was very popular with users because of the wide variety of exercises possible and the relatively inexpensive apparatus required. However, popularity waned over time as they were perceived as providing an unacceptably high risk of injury. Developments in safety such as those provided by CA 2023385 did not result in significantly more widespread use of free weight lifting apparatus, apparently because the barbell may still drop a considerable distance and cause injury to the user. Indeed, it could be said that while the barbell will only drop a certain distance to the pre-determined height if the user releases it, once the barbell has been lifted from this pre-determined height, the user may not regard the apparatus as being different from one without safety features, and will tend to hold the barbell as long as possible. This may result in injury such as back strain. The safety problems of free weight lifting apparatus helped to cause a major shift towards "fixed" apparatus in which the weights are lifted indirectly. A simple example is a bench press in which the user pulls handlebars against the force of weights at the other end of a lever. If the user releases the handlebar, the weights drop in a safe manner onto the base of the apparatus. However, more recently, it has become apparent that a different type of safety problem is associated with fixed apparatus. This problem is strain of the back or other parts of the body caused by the fact that the users hands must follow a pre¬ defined path, which path is sometimes incompatible with the posture. This path may, for example, be an arc around a lever fulcrum.

The invention is therefore directed towards providing improved safety in free weight lifting.

The invention is characterised in that:-

the lock comprises an actuator and is operable in response to the actuator to prevent movement of the links whereby the barbell may be suspended by the links substantially at any desired height.

Because of the manner in which the lock operates, the links are immediately or almost immediately prevented from moving so that the barbell does not drop. This means that a user can release the barbell at any time during an exercise, safe in the knowledge that it will not drop as it remains substantially at the desired height. In these circumstances, the user is unlikely to have any reluctance to release the barbell and will therefore do so as soon as strain starts to become noticeable. This is a fundamental difference from the prior art in which the user may psychologically regard the apparatus as being the same as a traditional free weight lifting apparatus without any safety features once the barbell has been lifted from the pre-determined height. It will be appreciated, therefore, that the invention provides significantly improved safety for a free weight lifting apparatus.

In one embodiment, the lock is biassed into a default locked state and is releasable only by action of the actuator. This is a particularly advantageous feature as any fault which arises in the actuator will not cause the lock to remain released any longer than is required. The worst than can happen is that the barbell is suspended at a height when the user does not desire it. It is, of course, much better for an exercise to be disrupted than for a safety problem to arise if a fault develops.

In one embodiment, the actuator comprises a user interface. This allows the user to control the lock according to his or her requirements. In this latter embodiment, the lock is preferably releasable only by a positive user input detected at the user interface. This is a very advantageous feature as it provides for locking if the user does not provide an input at the interface. Accordingly, the user is free to simply release the barbell and avoid providing an input into the interface to allow the barbell to be suspended.

In one embodiment, the user interface comprises a handle having means for mounting on the barbell and a connector linking the handle with the other parts of the lock. This is one particularly suitable method of providing a user interface. The connector may be a cable, or alternatively it may comprise a fluid line. If a fluid line, the line preferably contains a gas and a liquid. An advantage of this arrangement is that the volume of gas such as air required is reduced by the volume of liquid such as oil and therefore, problems which could arise by expansion and contraction of the gas are avoided. The presence of a gas in the line provides a resilience whereby action of the handle may cause the gas to be compressed and provide a fast action of the lock.

In an alternative embodiment, the actuator comprises means for sensing dropping of the barbell for automatic operation of the lock. Numerous different sensors could be provided to detect dropping of the barbell. For example, a roller on each belt could be provided to detect downward movement of the links. Alternatively, an optical sensor may be used. It is also envisaged that mechanical arrangements such as non-reversible cleats could be used to detect dropping of the barbell. In this embodiment, the user may not be required to provide an input, in which case the barbell will be automatically suspended at the current height if it is released.

In one embodiment, the guide means comprises spools for gathering the flexible links and bias means for urging rotation of the spools to gather the links, the lock comprising means for preventing rotation of the spools. This is a particularly suitable way of maintaining the links taut and also of locking them at a particular height. Spools are inexpensive and robust.

Preferably, the guide bias means comprises a counter¬ weight suspended by a link wound on a spool connected to the guide spools. This is a very effective way of biassing the spools to gather the links as a consistent bias force is provided at all times. Provision of springs to provide the bias with a constant spring force is difficult and expensive and springs are unlikely to be as reliable as the counter-weight arrangement. In one embodiment, the guide spools and the counter¬ weight spool are mounted on a single shaft. This is a simple way of interconnecting the counter-weight spool and the guide spools to provide the necessary gathering bias .

In one embodiment, the lock comprises a ratchet and pawl mechanism connected to the guide means . This is a particularly robust and inexpensive mechanism.

In this latter embodiment, the pawl is preferably biassed by a spring and a counter-weight into the default locked position. This provides for improved safety as failure of either the spring or the counter-weight will still cause the lock to move to the locked state by default.

In one embodiment, the ratchet is a ratchet wheel. Preferably, the guide spools, the counter-weight spool and the ratchet wheel are mounted on a common shaft. This is a particularly simple and convenient way of providing the guide means and the lock.

In one embodiment, the lock comprises a plurality of ratchet wheel and pawl mechanisms, the ratchet wheels being mutually offset in angular relationship. By being mutually offset, there is a slight difference in time between engagement of the mechanisms to reduce the delay before the first one engages. It also helps to prevent a pawl missing a tooth of the wheel. Mounting of the ratchet wheels in this manner is very simple.

The invention will be more clearly understood from the following description of some embodiments thereof, given by way of example only, with reference to the accompanying drawings in which:- Figs. 1(a), 1(b) and 1(c) are diagrammatic side views showing an apparatus of the invention in use;

Fig. 2 is a perspective view from the front of the apparatus;

Fig. 3 is a front view of the apparatus;

Fig. 4 is a perspective view of the apparatus from above and behind;

Fig. 5 is a diagrammatic cross-sectional side view showing operation of a lock of the apparatus; and

Figs. 6(a), 6(b) and 6(c) are various views showing an actuator handle of the apparatus.

Referring to the drawings, there is shown a weight lifting apparatus 1 of the free type. The apparatus 1 comprises a steel support frame 2 having a base 3 with adjustable feet 4. The frame 2 also comprises uprights 5 supporting a top portion 6, which in turn supports various functioning parts of the apparatus 1. Uprights 5 at the rear of the apparatus 1 have protruding arms 7 for supporting weights when not in use.

The apparatus 1 is shown with weights 9 supported on a barbell 10. The barbell 10 is suspended by a pair of flexible links, namely, belts 11. The top portion 6 of the apparatus 1 supports a control shaft 12 which is rotatable on bearings 13. The belts 11 are connected to a guide means comprising a pair of guide spools 15 around which they are wound. There is a guide spool 15 on each side of the apparatus 1 and a counter-weight spool 16 is mounted centrally on the shaft 12. The counter-weight spool 16 is part of a mechanism to urge the guide spools 15 to rotate in a direction whereby the belts 11 are gathered as the barbell is lifted. A belt 17 is wound on the counter-weight spool 16 and is connected at its lower end to a counter-weight 18 which runs within a track 19 at the rear of the support frame 2.

There is a lock 25 adjacent each guide spool 15, a lock being shown in detail in Fig. 5. Each lock comprises a ratchet wheel 26 fast on the control shaft 12. There is a pawl 27 for engagement with each ratchet wheel 26 and each pawl 27 comprises a tooth 28 for engagement with corresponding teeth on the ratchet wheel 26 and each pawl is pivotable about a pivot pin 29. Each pawl 27 is urged into engagement with the associated ratchet wheel 26 by both a set of springs 30 and a counter-weight 31. The springs 30 urge the tooth 28 of the pawl 27 upwardly, the same direction as that urged by the counter-weight 31 at the other side of the pivot pin 29. Each lock 25 also comprises an actuator 40 shown most clearly in Figs. 6(a), 6(b) and 6(c). Each actuator 40 comprises a handle 41 which is adjustable in position along the length of the barbell to suit the user and is also rotatable about the barbell as shown in Fig. 6(c). The handle 41 is curved to the shape of the barbell so that it only protrudes slightly from the surface of the barbell to provide a neat and convenient grip for the user. The extremity of each handle 41 moves within a block 42 within which it is connected to a cable connector 43 which runs in a sleeve 44. As shown in Fig. 5, the other extremity of the cable 43 is connected to the pawl 27 whereby pushing of the handle 41 downwardly against the barbell causes the cable 43 to pull the tooth 28 out of engagement with the ratchet wheel 26.

In operation, the apparatus 1 is mounted on the ground with the adjustable feet 4 being used for levelling if this is required. The user attaches the required weights 9 onto the barbell 10, being informed beforehand of the weight of the counter-weight 18 so that he may make an allowance for this. At all times, the barbell 10 is suspended by the belts 11 and accordingly, it is at a particularly convenient position for the user to apply the weights without excessive bending.

To perform an exercise, the user slides the handle assemblies along the barbell until they are at the desired positions. They will remain in this position because of friction between the block 42 and the barbell, however, it is envisaged that a fastener of any suitable type may be used to provide a more positive engagement. Referring to Figs. 1(a), 1(b) and 1(c), when comfortable and ready to take the weight of the barbell 10, the user pulls the handles 41 against the barbell. He may do this without actually taking the weight of the barbell provided he does not lift at the same time. However, immediately upon lifting the barbell by a very slight distance, the resilience of the cable 43 will cause the pawl to snap out of engagement with the ratchet wheel 26 so that the user then takes the full weight of the barbell . The user then lifts the barbell in conventional manner. While lifting, the user holds the handles 41 against the shaft, thereby providing a positive user input to keep the locks released. As the user lifts the barbell, the guide spools 15 rotate under the action of the counter-weight 18 in order to keep the belts 11 taut at all times. When the user is finished the exercise, or if he experiences strain, he simply releases the handles 41 as shown in Figs. 1(b) and 1(c) thereby allowing the locks to return to the default, locked state. When this happens, the barbell will only drop a very small distance corresponding to that required for engagement of the pawls with their associated ratchet wheels. This is no more than the pitch of the ratchet wheel. Indeed, in this embodiment, the ratchet wheels are mounted on the control shaft 12 in a manner whereby they are offset in angular relationship by 5°. Accordingly, one lock will engage a very short period of time before the other to provide for a faster response. This also helps to ensure that the locks do not slip. Immediately when the user has released the barbell 10, therefore, he may walk away from the apparatus.

It will be appreciated that at all times during the exercise, the user will be conscious of the fact that he may release the barbell at any stage without fear of the barbell dropping any appreciable distance. This is a fundamental improvement on the prior art in which the user knows that the barbell will drop to the initial height if he releases it. The invention therefore provides for a major improvement in safety of weight lifting exercises, without the attendant problems which are associated with fixed weight lifting.

It will be appreciated that the arrangement of guide spools and counter-weight provide a very simple and effective manner of gathering the belts as the barbell is lifted with a consistent bias force. It will also be appreciated that the locks 25 are of a very simple and reliable construction. Because the guide spools, the counter-weight spool, and the lock ratchet wheels are all mounted on the control shaft 12, there is little or no chance of a fault arising in interconnection of the various parts and the arrangement is very simple and inexpensive to produce.

The invention is not limited to the embodiments hereinbefore described. For example, it is envisaged that the lock may not be biased into a default locked state and action of the actuator may be required to cause it to be locked. It is also envisaged that the actuator may comprise a sensor for automatic operation instead of or in addition to a user interface. Such a sensor may take many different forms. It is envisaged, for example, that an accelerometer-type roller connected to the belts may detect reversal of direction of the belts and the speed with which this takes place may cause the locks to become engaged. It is also envisaged that an optical sensor could be used to detect dropping of the barbell. The important point is that when the sensor detects dropping of the barbell at a pre-determined rate, it causes the locks to become engaged. Where there is no user interface, the actuator may cause the locks to become engaged when the barbell drops at greater than a pre- determined rate. If the barbell is deliberately lowered down by a user at a slower rate than this, it may be moved to a desired height without the lock becoming engaged.

Where the actuator comprises a user interface, this may alternatively be provided by a foot pedal.

The connector which links the handle to the lock may alternatively comprise a fluid line. Where the fluid line contains only a gas such as air, expansion and contraction of the gas could cause a lack of reliability if the fluid line has a relatively high volume. This problem may be overcome by inclusion of oil or some other liquid within which the gas is not soluble within the line. An advantage of using gas such as air in the line is that pressing of the handle causes the gas to be compressed to some extent, thereby storing energy which may be used to cause the pawl to snap out of engagement immediately when the barbell is lifted by a slight amount. This effect is provided in the described embodiment by a cable having some resilience. It is also envisaged that the handle may be connected to the other parts of the lock by use of an electronic or electrical connection, or indeed by radiation signals.

It is also envisaged that instead of belts, the flexible links may comprise cables or chains. If chains are used, they could engage sprockets at the top of the apparatus and rotation of the sockets may be controlled by the locks .

The invention is not limited to the embodiments hereinbefore described, but may be varied in construction and detail.

Claims

1. A weight lifting apparatus comprising a support frame, flexible links for connection to a barbell, a guide means for maintaining the links taut during lifting of the barbell, and a lock for the guide means, characterised in that,

2. An apparatus as claimed in claim 1 wherein the lock is biassed into a default locked state and is releasable only by action of the actuator.

3. An apparatus as claimed in claim 1 or 2, wherein the actuator comprises a user interface.

4. An apparatus as claimed in claim 3, wherein the lock is releasable only by a positive user input detected at the user interface.

5. An apparatus as claimed in claims 3 or 4 , wherein the user interface comprises a handle having means for mounting on the barbell and a connector linking the handle with the other parts of the lock.

6. An apparatus as claimed in claim 5, wherein the connector is a cable.

7. An apparatus as claimed in claim 5, wherein the connector is a fluid line.

8. An apparatus as claimed in claim 7, wherein the fluid line contains a gas and a liquid.

9. An apparatus as claimed in claim 1 or 2, wherein the actuator comprises means for sensing dropping of the barbell for automatic operation of the lock.

10. An apparatus as claimed in claim s 1 to 9, wherein the guide means comprises spools for gathering the flexible links and bias means for urging rotation of the spools to gather the links, the lock comprising means for preventing rotation of the spools.

11. An apparatus as claimed in claim 10, wherein the guide bias means comprises a counter-weight suspended by a link wound on a spool connected to the guide spools.

12. An apparatus as claimed in claim 10, wherein the guide spools and the counter-weight spool are mounted on a single shaft.

13. An apparatus as claimed in any preceding claim wherein the lock comprises a ratchet and pawl mechanism connected to the guide means.

14. An apparatus as claimed in any of claims 2 to 13, wherein the pawl is biased by a spring and a counter¬ weight into the default locked state.

15. An apparatus as claimed in any claims 13 to 14, wherein the ratchet is a ratchet wheel.

16. An apparatus as claimed in any of claims 10 to 15, wherein the guide spools, the counter-weight spool and the ratchet wheel are mounted on a common shaft.

17. An apparatus as claimed in claim 15 or 16, wherein the lock comprises a plurality of ratchet wheel and pawl mechanisms, the ratchet wheels being mutually offset in angular relationship.

18. An apparatus substantially as hereinbefore described, with reference to and as illustrated in the accompanying drawings.