BACKGROUND OF THE INVENTION Field Of The Invention:

The present invention relates generally to exercise devices and more particularly to a device for use in exercising, developing and toning hand, arm and wrist muscles and upper body muscles.

Description Of The Prior Art:

Various sports including golf, tennis and baseball require that the players have unusually strong wrist, hand and arm muscles. Even football players, especially offensive linemen, require particularly strong hand, arm and wrist muscles to facilitate their blocking assignments. Moreover, a lack of conditioning of certain muscles may result in various chronic ailments which cause pain and lessen enjoyment and abilities in the pursuit of athletic activities. For example, weakness of the lateral epicondyle of the humerus causes the common "tennis elbow" which may hinder the professional athlete in pursuit of his goals for success and which may dissuade the recreational player from enhancing his skills and furthering his enjoyment. Another commonly recognized problem is that of "golfers elbow" which is caused by weakness of the medial epicondyle of the humerus. This condition can also hinder both the professional and recreational golfer in pursuing their respective goals. The most common method of strengthening those muscles has been in the use of free weights which the athlete uses in wrist curl exercises. Such exercises have proven successful in merely strengthening, for example, the wrist. However, they are not particularly useful in strengthening the entire hand, wrist and arm sections and they also have proven detrimental to the flexibility of the joints. One prior art device has been proposed in an attempt to overcome the above-described deficiencies. This exercise device is disclosed in U.S. Patent

3,184,234 to Struble. Struble provides a device in which handgrips are mounted on a mounting bar such that they can rotate with respect to one another. Adjustable end members 22 are threaded onto the ends of the mounting bar to maintain the handgrips therebetween and to provide adjustment of the amount of friction which opposes rotation of the grip members. The Struble exercise device, however, is somewhat undesirable in use because, if the user is not careful during adjustment, he may cause the device to disassemble by tightening down on one end while the opposite end loosens, thus pushing the grip members off of the end of the mounting bar. Furthermore, upon extended use, the tension producing parts wear and the device tends to become less resistant to turning and thus frequent adjustment is required. In particular, lock washers positioned between the ends of hand grips and the adjustment knobs have rectangular apertures which fit over rectangularly undercut ends of the central rod. As the hand grips are rotated, the washers also attempt to rotate and wear their central apertures. More rotation is therefor transmitted to the adjustment knobs causing them to loosen and tension to back off. In addition, the rotational motion of the device may become sharp and jerky producing unwanted strain on the muscle groups being exercised. The device is also relatively light in weight. Because of this, the advantages attained in using free weights are not realized during the use of this prior art device. That is, by exercising with relative heavy weights a greater variety of muscles are affected during the exercise and the exercise will provide more effective and acute muscle toning and development.

Other prior devices include those of Lopez, U.S. 4,337,937; Williams, U.S. 3,211,453; Zinken, et al. U.S. 3,649,008; Petrosky, U.S. 4,982,950; Sloan, Jr.,

U.S. 684,117 and Goddard, British 161,282. However, none of these devices provide the combination of elements of

the present invention whereby variable friction resistance is obtained in combination with smooth exercising motion while overcoming the mechanical disadvantages of Struble.

SUMMARY OF THE INVENTION

The present invention provides a variable tension and resistance exercise device for use in developing and toning arm, hand, wrist and upper body muscles, wherein the device is capable of variable resistance adjustment and smooth operative motion for efficient and useful exercise while avoiding or overcoming the inherent disadvantages of the prior art devices.

In accordance with the present invention, there is provided a mounting bar upon which two handgrip elements are rotatably mounted. Between these handgrip elements on the mounting bar there is fixably mounted a center stop collar which prevents the pushing off of one of the handgrip elements by the other handgrip element because the center stop element insulates each handgrip element from any inwardly directed force exerted on the other handgrip element.

Each end of the mounting bar is screwthreaded to receive a cylindrical shaped weight with a screwthreaded bore therein. Located on the mounting bar between each handgrip element and each end weight, respectively, is an end stop collar of substantial thickness having a set screw acting against a flat surface of the mounting bar or other means to prevent rotation of the collar. However, the end stop collars are permitted to be displaced slightly axially inwardly toward the handgrip elements upon screwing the end weight compressively thereagainst. Such inward adjustment of the end weights causes frictional resistance to the turning of the handgrip element to increase correspondingly.

Between each end stop collar and its respective handgrip is a compression assembly comprising a rubber compression member flanked by flat washers. Inward adjustment of the end weights compresses these assemblies between the end collars and the handgrips which, in turn, increases the frictional resistance of the handgrips. Additional washers of a material which provides a variable degree of friction depending on the level of compression while allowing slippage of adjacent parts facilitate rotation of the compression assemblies relative to the end stop collars even under tight compression, thus preventing transmission of handgrip rotation to the end collars and thence to the end weights. Additional washers of this material are preferably placed between the end collar and end weights and between the handgrip elements and the center stop collar.

Accordingly, it is an object of the present invention to provide a device which allows for the development and toning of a unique combination of muscles.

It is a further object of the present invention to provide an exercise device which is relatively inexpensive and useful for developing and toning hand, wrist, arm and upper body muscles.

It is yet another object of the present invention to provide a friction exercise device which combines the advantages of free weights with the advantages of a frictional rotation exercise device. It is a still further object of the present invention to provide a friction rotation exercise device which allows for adjustment of the frictional resistance while maintaining a smooth rotation of the handgrip elements. Yet another object of the present invention is to provide a frictional rotation exercise device which

has two end adjustments, yet does not allow accidental disassembly of the device.

A further object of the present invention is to provide a frictional rotation exercise device which tends to retain a constant frictional resistance during continued use.

The present invention will be more fully described hereinbelow in connection with the accompanying drawing figures.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

Figure 1 shows an elevation view, in cross- section, of the rotation exercise stick of the present invention.

Figure 2 shows an exploded view of the exercise stick of Figure 1.

Figure 3 shows an oblique view of the exercise stick of Figure 1.

Figure 4 shows an oblique view of an alternative form of stop collar employed in the exercise stick of this invention.

Figure 5 shows an exploded view of an alternative center stop collar assembly of the present invention.

DETAILED DESCRIPTION OF THE INVENTION The exercise device of the invention will be described with reference to Figs. 1 and 2. The handgrip exerciser 10 includes a mounting bar 12 which is preferably formed of steel and is of a circular cross section, except for one flat side thereof shown at 52. Rotatably mounted on the mounting bar are two handgrips 14 having a cross-sectional diameter of 1-2 inches, preferably about 1 1/2 inches. While the handgrips can be formed of various materials in the preferred embodiment, they include a dowel 16 with a centrally located longitudinal bore 20 therethrough. A

handgrip material 18 is fit onto the outer periphery of the dowel 16 so as to provide a comfortable handgripping portion. This handgrip material may be of various materials that provide cushioning and wear resistance, including cushioned tape, leather, vinyl backed foam, or the like, but is preferably formed of nitral foam. The grip material may be either friction fit over the dowel 16 or bonded thereto by means of any suitable adhesive. The dowel 16 is preferably made from wood but may also be made from solid plastic, aluminum, or similar material with the centrally located longitudinal bore 20 therethrough.

Located centrally on the mounting bar 12 is a center stop means 22 which is fixedly mounted to the center of the bar by a screw 24 which bears against the flat portion 52 of the mounting bar 12 with sufficient force to prevent rotation and axial shifting of center stop means 22. In the preferred embodiment, the screw 24 is of the Allen screw type and is permanently set within its aperture 23 of the collar 22 by a commercially available adhesive such as Loc-tite. Flat or round head screws may also be used.

Center stop means 22 may be a single cylindrical member which may have a diameter equal to that of dowels 16 and a central bore for passage of bar 12. More preferably it is a smaller diameter collar 53, as seen in Figure 1, having a diameter of from 1/2" to 3/4" and a thickness of from 1/4" to 1/2". Washers 54 having diameters equal to that of dowels 16 are mounted against the inner ends of handgrip elements 14 to prevent wear on the ends of dowels 16 by collar 53. Washers 54 have centrally located round holes corresponding to the bore 20 of dowels 16 for passage of mounting bar 12 and to allow washers 54 to rotate. The handgrip elements 14 are mounted on the mounting bar 12 on opposite sides of the center stop means 22. Sandwiched between the center stop collar 53

and the washer 54 on each side of the center stop collar 53 is a washer 25 mounted over the mounting bar 12 and made from a material which provides a variable coefficient of friction depending on the level of compression to which it is subjected and of substantially the same diameter as the center stop collar 53. The washers 25 may have a larger diameter but must be at least as large as center stop collar 53. A preferred material for washers 25 is carbon impregnated polytetrafluoroethylene such as DuPont TEFLON which provides the variable coefficient of friction as well as a degree of lubricity which is necessary for effective rotation of the handgrip elements 14 relative to center stop collar 53 so that the rotation is smooth even when the level of friction is high. Other materials may be used; however, the inventor herein has found that the optimum material is TEFLON impregnated with carbon to a level of 20-25% by weight. By using washers made of this material in the structure of the exercise device herein, the inventor is able to provide a device wherein the level of frictional resistance can be varied while maintaining a smoothness of operation which enhances the useability of the device. In addition, the degree of lubricity offered by the TEFLON reduces the incidence of wear which has been a problem in other devices of this type. The smoothness of operation coupled with the variable friction resistance is important to efficient exercise. If the carbon content is too low, it is not possible to obtain the friction which provides the variable resistance for exercise. Similarly, if the carbon content is too great, the level of friction becomes such that the rotation of the handgrips 14 becomes jerky and uneven which is counterproductive to efficient and useful exercise. End stop collars 28 are mounted on the mounting bar 12 outside of the handgrip elements 14. These collars 28, as with the central stop means 22, may

include screws 30 which are tightened down against the flat side 52 of the mounting bar 12. These screws 30 prevent rotation of the end stop collars 28 and also prevent the collar from being pushed or taken off of the end of the mounting bar 12. They may be set in as shown in the drawings or they may be round or flat head screws of appropriate size. However, screws 30 are not so tight as to prevent slight axial movement along bar 12 in response to tightening of end weights 26. End stop collars 28 are preferably the same size as the center stop collar 53.

Sandwiched between end stop collars 28 and handgrip elements 14 are compression assemblies 32 comprising rubber compression elements 40 mounted over the mounting bar 12 and steel washers 41 and 42 mounted on bar 12 on either side of the rubber compression element 40. The rubber element 40 and washers 41 and 42 all have centrally located holes which are round in shape. In this manner, the compression assemblies may turn upon mounting bar 12 with handgrip elements 14. Rubber elements 40 are made from a rubber composition having a durometer hardness of from 80 to 100. This level of hardness is important to the invention since, if it is too low the rubber element will be caused to extrude out from between the washers 41 and 42. Conversely, if the hardness level is too high, the range of tension adjustment possible with the device will be reduced since the compressive force generated will be more completely passed directly to the handgrips 14 and, thereby, to the center stop means 22. The preferred range of durometer hardness is 85-95 with a most preferred range being 85-90 durometer. The inventor herein has found that the combination of rubber elements 40 having a hardness of most preferably 85-90 durometer and the variable friction washers 25 of 20-25% carbon impregnated TEFLON when employed in the structure of the exercise device of this invention result in a wide range

of adjustable tension not previously obtainable in such devices. Furthermore, the combination produces a smooth rotation of the handgrips 14 when the exercise device is used without any jerkiness of motion caused by parts catching or dragging which jerkiness can put excessive strain on the muscles being exercised. It is well established that smooth, non-jerking force or operation of equipment is desired for proper, even exercise of muscle groups. Sudden jerky or sharp movements of equipment do not produce smooth, even extension and contraction of muscles during exercise and, instead, place excessive stress and strain on the muscles which can cause injury and reduce the efficiency of the exercise being performed. Each end of the mounting bar 12 includes a threaded portion 50. This threaded portion 50 provides two functions. First, it allows the screw of the end stop collar 28 to be tightened down to an extent where the collar 28 can move slightly in the axial direction, yet not move over the end of the mounting bar 12 because it contacts the threaded portion 50. The threaded portion 50 also provides for the rotatably adjustable receipt of end weights 26. These end weights 26 are preferably cylindrical and may be formed of cold rolled steel or other suitable material. They each include a tapped bore 48 formed into one end thereof so as to receive the threaded end portion 50 of the mounting bar 12.

Washers 54 prevent excessive wear of the dowel 16 which forms the handgrip element 14 on the ends adjacent center stop means 22. A protective washer 43 formed preferably of the carbon impregnated TEFLON material previously discussed is disposed on the mounting bar 12 adjacent the outer end of each dowel 16 between the dowels and compression assemblies 32. Similar carbon impregnated TEFLON washers 44 and 45 are disposed on the mounting bar 12 between each of the respective end stop

collars 28 and end weights 26 and between end stop collars 28 and compression assemblies 32. Preferably, however, the washers 45 are of pure virgin TEFLON and the washers 44 are of carbon impregnated TEFLON. Alternatively, carbon impregnated TEFLON washer 43 may be eliminated and compression assembly washer 42 may be fixed to the end of dowel 16 so that relative rotation of handgrips 14 and compression assemblies 32 is eliminated and, instead, relative rotation takes place between the compression assembly handgrip combination and end stop collar 28 due to the lubricity factor of carbon impregnated TEFLON washer 44. Being made of the carbon impregnated TEFLON material, washers 44 contribute to the level of friction induced tension upon compression by tightening the end weights 26 against the end stop collars 28. These washers allow the end weights 26 to be compressively threaded against the handgrip elements 14 without binding and assist in the turning of compression assemblies 32 upon mounting bar 12, relative to the end stop collars 28.

In an alternative embodiment, illustrated in figure 5, center stop means 22 may be built up from a smaller diameter stop collar 53 with large diameter washers 54 positioned on either side and attached to the collar by means of an appropriate adhesive or by welding. In this embodiment washers 54 will then have centrally located holes shaped with a flat side to correspond to the cross-sectional shape of mounting bar 12. This shape together with screw 24 will prevent center stop means 22 from turning upon mounting bar 12. This construction may also be achieved by a single molding or casting in various materials including reinforced polymers, sintered metal powder and the like. With this construction, the carbon impregnated TEFLON washers 25 will be positioned between washers 54 and the inner ends of dowels 16 and will be the same diameter as dowels 16 to facilitate the

tensioned rotation of the handgrip elements 14 relative to center stop means 22.

Also alternatively, center stop collar 53 and end stop collars 28 may be formed with central bores having a flat area corresponding to the flat portion 52 of mounting bar 12. Figure 4 shows a representative form of such a collar 55 with bore 56 having flat area 57 extending longitudinally at least partway along bore 56. Preferably, the dimensions of bore 56 and flat 57 are in close tolerance with the shape and size of bar 12 to provide a tight fit and prevent any attempted rotational movement of collar 55 thereon. In addition, the thickness of the collar 55 eliminates the tendency for the bore 56 to wear against the bar 12 which is a problem in the prior art devices. Where this configuration is used, screws 24 and 30 may be eliminated, although it is preferred that screw 24 in center stop collar 53 be retained to secure against lateral movement of collar 53 along bar 12. In operation, the user grips each handgrip element 14 with one of his hands and rotates it back and forth while retaining his grip. Various exercises can be performed with this handgrip exercise device, such as a simple exercise in which the user grips each handgrip element holding his arms straight out in front of him with his palms down and rotates each handgrip element back and forth to the extent which he is able. This rotating action exercises, tones and develops arm, hand and wrist muscles. When the user holds the weighted device outwardly from his chest it also provides upper body muscle toning and development. Another example of an exercise which can be performed with the device is that of gripping the handgrip elements with each hand in opposite directions and holding the device outwardly such that the user's arms are straight out in front of him and his hands are positioned one above the other. He then

rotates the handgrip elements, as in the first noted example, to the full extent he is able.

It should be noted that with the present device, various amounts of end weight can be provided on each end of the bar by the provision of larger or smaller end weight elements 26. In the preferred embodiment, the two weights total either 2, 3, 4 or 5 pounds. The frictional resistance to turning of each handgrip element may be adjusted by rotation of either one or both of the end weights 26. Rotation in one direction causes the end weights 26 to press axially inwardly upon the end stop collars 28, the grip elements 14, and the compression assemblies 32. The rubber compression elements 40, of course, tend to provide a resistance force both outwardly against the inward adjustment of the end weights and inwardly against the handgrips, thus, the resistance adjustment is variable and evenly distributed across all levels of tension. This even distribution is a direct result of the durometer hardness of the rubber elements 40 which is sufficient to prevent them from being extruded from between the washers 41 and 42 but not so hard that they are not compressible. The fixed nature of center stop means 22 provides a fixed stop against which the resistance force of the compression assemblies 32 can push. In a similar manner, center stop means 22 prevents tightening of one end of the device from loosening or pushing off the other end of the device and allows the resistance of each hand grip to be independently adjustable. Thus, it can be seen that the handgrip exercise device 10 of the present invention can be used by persons of all ages and strengths. For those with less developed hand, wrist, arm and upper body muscles, relatively light end weights 26 can be used and the end weights 26 can be adjusted such that relatively small frictional forces act against the rotation of the grip elements 14. Conversely, those with more developed muscles can use

larger end weights 26 and adjust them inwardly such that a greater resistance force acts against the turning of the grip elements 14.

Various changes and modifications may be made to the preferred embodiments disclosed without departing from the spirit and scope of the present invention. Thus, it is to be understood that the invention is to be limited in scope only by the appended claims.