Hydraulic Torque Reaction Wrist and Arm Exerciser

This invention relates to an improved wrist and arm exerciser generally of the type employing hand grips and a resistance torque device therebetween that reacts to and resists relative turning motion applied through the hand grips. The invention is herein illustratively described by reference to the presently preferred embodiments thereof; however, it will be recognized that certain modifications and changes therein with respect to details may be made without departing from the essential features involved.

It has long been known, of course, that the development and strengthening of wrist and arm muscles can be accomplished through daily exercises that repeatedly stress the muscles and that uniformity of development requires working all the muscles. Among the better exercises of this nature are those which require the participant to pit the strength of one arm against the other. While "isometrics" excercises can be performed in variety sufficient to work most of the muscles, it is found that muscle strains that change due to motion or changes of position are very helpful. For example, wrist and arm exercises involving forceful turning of a rotary resistance torque device held between the hands about an axis parallel to the line of the shoulders and that may, if desired, be canted into different orientations relative to that line in order to vary the exercise are highly effective. Exerting turning force first in one direction and then oppositely in alternate sequence over a period of time, with the exercises graduated from easy beginnings to more strenuous effort as the strength and stamina of the participant develop are highly effective.

In the course of investigating prior art exercising devices, a number of United States patents were located of varying degrees of interest and pertinence as background to the present improvements. These are as follows: U.S. Pat. Nos. 3,955,655; 3,944,221; 3,807,729; 3,764,131; 3,717,338; 3,495,824; 3,396,967.

An important purpose of the present invention is to provide a rotary resistance torque type wrist and arm exerciser that, unlike those employing relatively rotatably elements worked against the increasing stress of a return spring, permits the user to incur or experience immediate selected resistance torque in response to and measured by turning effort applied in either direction through the hand grips. Another and related object is to provide such an exerciser that eliminates the disadvantages of working against friction discs or bands rubbing together. Wear, static friction to be overcome and a tendancy for resistance torque to decrease as relative rotation speed between the discs or bands is increased tend to impose certain torque charateristics on devices of this nature that are considered to be less than satisfactory.

An important object is to overcome such difficulties and limitations in a device of small bulk and weight requirements and economical to manufacture. More specifically, it is an object hereof to provide a device the units of which can be started into relative rotation smoothly without encountering a large starting resistance in either direction of rotation. A further object hereof is to devise a wrist and arm exerciser in which the resistance torque developed within it increases with attempts to increase the relative rotational speed of the units and which thereby inherently affords to the user a wide range of exercise forces available to the user without the necessity of making any mechanical adjustments. However, it is also an object hereof to devise such a mechanism or exerciser with provision for convenient adjustability of the relative rotation resistance torque characteritic thereof.

Still another object hereof is to provide a versatile exerciser in which the resistance torque device therein is readily adapted for interchangeability of hand grips of different types, including rounded knobs that enable the user to grip and hold the unit in different hand positions, thus to vary the exercises of the muscles in the wrist and forearms, and also a scissor-type hand grip arrangement in which the forces are borne in a different manner by the wrists and forearms without less taxing of the hand muscles.

As herein disclosed, the invention resides in an exerciser comprising a pair of hand grips and a resistance torque device including first and second units respectively mounting the hand grips and interconnected to permit relative rotation therebetween about a common axis. Formed cooperatively by or within the first and second units of the torque device, is an annularly extending chamber sealed to hold hydraulic fluid such as grease. One of the units incorporates partition means forming opposite end walls for the chamber and the other unit incorporates a vane projecting therefrom into the chamber in a sliding fit and serving as a two-way plunger dividing the chamber into compartments that are varied oppositely in volume by the vane accompanying relative rotary motion of the units one way or the other. The force required through the hand grips to rotate the units relatively is determined by the viscosity of the fluid chosen and by the size or calibration of a flow restriction permitting the fluid to pass from one compartment to the other accompanying relative rotation between the units. While the flow restriction may, for example, comprise an aperture through the partition means in the first unit, it is perferably an aperture through the vane on the second unit.

As a further feature a screw threaded through the second unit into the aperture through the vane permits controlling the size of the aperture from the exterior of the device in a convenient manner.

Still other features reside in providing such an exerciser having hand grips that are symmetrically rounded in the form of knobs permitting the user to grip the same with the hands in varying positions and thus thereby to exercise the wrists and arm muscles in different ways. For example, the hands may be applied to such grips with the palms facing each other, or with both palms facing upward, with both facing downward, or with one palm facing upward and the other facing downward, or at various intermediate angular orientations relatively. In this way the muscles around the entire perimeter of the wrists and forearms can be exercised selectively and in repeating cycles by alternately reversing the direction of relative rotation.

With the hand grips removably mounted on the exerciser resistance torque units, another form of hand grip may be substituted, comprising elongated handles mounted at right angles to the rotation axis of the exerciser may be employed and in this way the user may work the exerciser back and forth in the manner of working the handles of pruning shears or the like.

These and other features, objects and advantages thereof will become more fully evident from the following description by reference to the accompanying drawings.

FIG. 1 is an isometric view of the improved exerciser having hand grips of the rounded knob type.

FIG. 2 is an exploded isometric view of the same exerciser shown in FIG. 1 with the parts separated axially.

FIG. 3 is an isometric view of one of the resistance torque device units showing the annularly extending hydraulic fluid chamber therein and other details.

FIG. 4 is a longitudinal sectional view of the exerciser shown in FIG. 1 taken on an axial plane to reveal interior details with the parts assembled.

FIG. 5 is an enlarged fragmentary sectional view illustrating the formation of the fluid impeller or vane on one unit cooperating with the chamber in the other unit and also illustrating the fluid seals and adjustment screw for varying the flow restriction through the vane aperture.

FIG. 6 is an isometric view illustrating an alternate handle arrangement for the improved exerciser.

Referring to FIGS. 1 to 5, the improved exerciser comprises a pair of hand grips 12 and 14 mounted upon and interconnected by a resistance torque device 10. The resistance torque device 10 includes first and second relatively rotatable units 16 and 18 which have parts that are formed and arranged to cooperate in such a manner as to develop the desired resistance torque characteristics set forth within the above statement of objectives.

Unit 16 preferably comprises a disc-like body 16a with an inner flat or planar face 16b perpendicular to the relative rotational axis A of the device. Opposite the face 16b the unit has an axially projecting tubular shaft 16c preferably provided with a circumferential series of longitudinally extending grooves that form ribs or keys between them designed to fit removably into similar grooves 12a in the wall of a longitudinal bore formed in the adjacent end of the hand grip knob 12. The body 18a of unit 18 is also of generally annular or disc-like form, but preferably somewhat thicker axially and is likewise provided with an axially projecting tubular shaft 18c. The exterior of shaft 18c is grooved longitudinally at intervals around its periphery so as to engage complemental ribs and grooves formed in the wall of a central bore in hand grip 14. Thus, the hand grips may be slipped longitudinally on and removed from the hollow shafts 16c and 18c and in the installed position will securely engage the respective shafts for application of rotational torque thereto.

The inner face of the annular body 18a is formed with an annularly extending groove or chamber 18b therein facing and in confrontal proximity to the opposing face 16b. A radial partition 18e is incorporated in the unit body 18a to form opposite end walls 18f and 18g for groove 18b.

The opposing unit body 16a has a radially extending vane 16e projecting from the end face 16b thereof and adapted to enter into the groove or chamber 18b with a sliding fit therein enabling it to function as a form of piston or paddle adapted to compress hydraulic fluid incorporated in the groove 18b against one end wall 18f or the other 18g, depending upon the direction of relative rotation between the units. A bore or aperture 16f extending laterally through the vane 16e permits hydraulic fluid to flow from one side of the vane to the opposite side accompanying relative rotation between the units. A threaded bore 16g in the body of the unit 16 receives an adjustment screw 16h, the tip of which can be caused to enter the aperture 16f by varying amounts in order to vary the size of the flow restriction afforded by the aperture.

Surrounding the annularly extending chamber 18b in the unit body 18a is a shallow aperture 18h adapted to receive an elastic "O" ring 20. A similar shallow aperture 18i in the unit body 18a surrounded by the groove 18b also accommodates an elastic "O" ring 22. These "O" rings project slightly from their respective grooves when nested therein so as to be compressed against the face 16b of unit body 16a when the units are secured together in relative operating positions as depicted in FIG. 4. Thus, the compressed "O" rings serve as inner and outer seals preventing escapement of hydraulic fluid trapped within the annularly extending chamber 18b and placed under compression in either of the two compartments thereof formed by the presence of the rotatively reciprocative vane 16e.

In order to interconnect the cooperating units in coaxial alignment so as to permit their relative rotation while preventing relative axial separation thereof, the hub or inner portion of the unit body 18a has a threaded axial bore 18j accessible through the hollow interior 18c' of the open end tubular shaft 18c. A somewhat larger bore 16n, unthreaded, formed axially in the unit body 16b is also accessible through the hollow interior 16c' of hollow tubular shaft 16c. With the hand grips 12 and 14 removed and the units 16 and 18 pressed together, with the chamber 18b filled with grease or other hydraulic fluid, the bolt 24 may be inserted through the hollow of shaft 16c until its shoulder 24a abuts the end face of unit body 18a and its threaded end portion projects beyond the bore 18j to receive the nut 26 installed through the opposite shaft bore 18c'. The underside of the head of bolt 24 presses against the step 16m as the shoulder 24a abuts the end face of unit body 18a. The distance between these elements (i.e., the under side of the bolt head and the bolt shoulder 24a) is such that tightening of the knob 26 on the bolt places the rubber "O" rings 20 and 22 under the desired degree of compression to effect a seal without unduly increasing the mechanical rubbing friction between the solid parts of the interconnected units 16 and 18.

Gussets or ribs 18k reinforce the junction between the tubular shaft 18c and the unit body 18a. Similar ribs 16k strengthen the junction between the unit body 16a and the tubular shaft 16c joined thereto.

As depicted, removable knob-like hand grips 12 and 14 are preferably spherically rounded, rather than being simply cylindrical, for example. As a consequence the device affords a greater variety of specific muscle exercises due to the greater variety of ways in which these grips may be held comfortably in the user's hands.

In operation, hydraulic viscosity of the fluid selected for incorporation in the chamber 18b directly affects the resistance to relative rotation and hence the amount of torque or force that must be applied by the user. The faster the user attempts to rotate the parts relatively, the greater the resistance or torque reaction encountered. This also applies to the starting force necessary to rotate the units in either direction from any starting position. It can be made either large or small depending upon whether the user attempts to rotate the units rapidly initially. For example, by the user exerting maximum effort from the start, full muscular stress can be developed throughout the entire relative rotational stroke in either direction. Alternatively, or slow and easy start can be succeeded by a progressive increase of effort as the stroke continues. In all cases the force required at all points throughout the stroke is wholly within the user's control and can be varied at will. There is no substantial starting friction to overcome such as in certain prior art devices. The head of calibration screw 16h is accessible from the exterior of the device permitting the tip of the screw to be advanced or retracted in the flow aperture 16f in the vane 16e so as to increase or decrease the resistance torque factor as desired.

In the embodiment shown in FIG. 6, the relatively rotatable units 26 and 28 mount radially extending arms 30 and 32, respectively, that are angled slightly toward each other in relation to a mid-plane perpendicular to the relative rotational axis between the units 26 and 28. These arms 30 and 32, respectively, carry hand grips 34 and 36 that, because of the aforementioned offset, are positioned substantially in the same plane perpendicular to the rotational axis of the units. Preferably the interior details of construction and the mode and manner of operation of the resistance torque device comprised in the units 26 and 28 is the same as or similar to the corresponding units in the first described embodiment.

The invention has thus been described in its presently preferred embodiments illustrative and not delimiting with respect to the intended scope of interpretation of the claims hereafter defining the novel combinations comprising the invention.