Double-acting Hydraulic Exerciser

Abstract

A double-acting, hydraulic exerciser composed of two telescoping tubes having handles attached to the ends thereof. The inner tube defines a chamber which is oil-filled and encloses a piston whose actuating rod is attached to the handle end of the outer tube. The piston divides the chamber into right and left sections and is provided with valves that function alternately to allow oil to pass from the right section to the left section when the tubes are brought together by the handles in a compression stroke, and to allow oil to pass from the left section to the right section when the tubes are pulled apart in an expansion stroke. Because of the incompressibility of the oil, the motion in the compression and expansion strokes is linear and affords uniform resistance to motion throughout the entire length of each stroke, so that the exercising effect is even and free of strain in both traction and expansion.

Description

BACKGROUND OF THE INVENTION

This invention relates generally to manual exercisers suitable for athletic and therapeutic purposes, and more particularly to a double-acting, isometric exerciser which requires an evenly-applied muscular force to effect compression or expansion.

One widely-used form of exerciser is constituted by an elongated coil spring or elastomeric band terminating in handles at either end. In order to stretch the spring or band, the user must exert a muscular force. Such exercisers and variations thereof are useful for chest expansion and arm muscle development. However, spring or elastomeric types of exercisers have distinct limitations, for they can only function unidirectionally.

A muscular force is required to expand the spring but when the spring is fully expanded, it must be released to permit it to recover its original length. Hence, the benefit to the user is restricted in that the muscles normally involved in traction are not developed by the exerciser, whereas those involved in expansion may become overdeveloped. This disparate type of muscular development is objectionable.

Another serious drawback characteristic of spring-type exercisers is that the resistance afforded to motion is not constant inasmuch as the tension of the spring varies with its degree of deformation. Thus, spring tension may initially be weak, but as the spring is pulled apart by the exerciser, its tension may increase beyond the aility of the user to stretch it without undue exertion.

In those instances where the exerciser is intended for physical therapy, as with patients having cardiovascular or other medical problems in which gentle forms of exercise are indicated, an uneven resistance to motion may be somewhat dangerous to the patient. When mild exercise is prescribed, it is important that the exerciser create no undue strain, and to this end it is vital that the resistance to motion imposed by the exerciser be even thoughout the stroke, without abrupt changes or jerkiness.

Because the limitations of spring-type exercisers have been recognized, various forms of pneumatically and hydraulically operated exercising devices have been proposed to provide better control of the resistance to motion. But exercisers of the type heretofore suggested do not produce a linear stroke in both tension and traction, and their resistance to motion is uneven, particularly in the case of pneumatic types which make use of compressible air.

SUMMARY OF THE INVENTION

In view of the foregoing, it is the principal object of this invention to provide a double-acting isometric exerciser which offers substantially uniform resistance to motion throughout the entire length of its compression and expansion strokes and which requires an evenly applied muscular force to effect such motion in either direction of movement.

More specifically, an object of this invention is to provide a bi-directional exerciser of the above-noted type, which operates hyraulically with an incompressible fluid.

Among the significant advantages of the invention are that the exerciser avoids undue strain arising out of uneven force resistance characteristics and affords a linear action which accelerates muscular development or rehabilitation. In a typical spring-type exerciser which inherently functions only in the expansion-mode, the force resistance attains an optimum level during a small portion of the total expansion stroke, whereas in the present invention, this optimum level is maintained in both directions in the course of the full stroke.

A salient feature of the invention is that the hydraulic exerciser is of simple, compact construction and is useable in a variety of exercising positions either by individuals or by couples.

Briefly stated, these objects are attained in a double-acting exerciser comprising inner and outer telescoping tubes whose ends have handles attached thereto, whereby the tubes may be pulled apart or brought together. The inner tube defines a chamber which is oil-filled and encloses a piston whose actuating rod is attached to the handle-end of the outer tube so that as the tubes are brought together the piston shifts axially to vary the ratio between the left and right sections of the chamber or either side of the piston.

The piston is provided with valves that function alternately to allow oil to pass from the right section to the left section when the tubes are brought together by the handles in the compression stroke, and to allow oil to pass from the left section to the right section when the tubes are pulled apart in the expansion stroke. Because of the incompressibility of the oil, the motion in the course of both strokes is linear and affords uniform damping or resistance to motion throughout the entire stroke length, so that the exercising effect is even and free of strain in both expansion and traction.

OUTLINE OF THE DRAWINGS

For a better understanding of the invention as well as other objects and features thereof, reference is made to the following detailed description to be read in conjunction with the accompanying drawing wherein:

FIG. 1 is a perspective view of a double-acting exerciser in accordance with the invention, shown at the end of the expansion stroke;

FIG. 2 is an elevation view of the exerciser shown at the end of the compression stroke;

FIG. 3 is a section taken through the exerciser in the course of the compression stroke; and

FIG. 4 is a section taken through the exerciser in the course of the expansion stroke.

DESCRIPTION OF THE INVENTION

Referring now to the drawings, there is shown a double-acting, hydraulic, isometric exerciser in accordance with the invention and including two interfitting tubes 10 and 11. The tubes may be made of a light weight metal such as aluminum or a synthetic plastic material such as high strength nylon or polypropylene.

The diameter of inner tube 11 is smaller than that of outer tube 10 so that tube 10 telescopes within tube 11. Attached to the end of the tube 10 is a single-grip type handle 12 and attached to the end of tube 11 is an identical handle 13. As shown in FIG. 1, the tubes may be pulled apart by the user by grasping their handles and moving the hands away from each other, or as shown in FIG. 2 the tubes may be brought together by moving the hands toward each other.

In practice, a single user yay operate the exerciser, or a couple may exercise, each holding one handle. To facilitate exercise by couples, the handles, instead of being in grip form, as shown, may take the form of handle bars, so that each individual may grasp the handle bar with both hands.

As illustrated in FIGS. 3 and 4, inner tube 11 is sealed at both ends to define a chamber which is oil-filled, preferably with a light-weight oil. Disposed within the chamber is a piston 14 whose actuating rod 15 projects from the end of the inner tube and is attached to the handle-end of the outer tube 10. Piston 14 is provided with flap-valves 16 of the type used in standard automotive shock absorbers. These valves alternately allow oil to pass through the piston in one direction only and act effectively as a throttle valve to produce a damping action resisting the compression of the exerciser and the expansion thereof.

When piston 14 travels to the right, the oil is forced through a flap valve (or through holes) into the left-hand section of the chamber, and when the piston moves back to the left, the oil flows through another valve back into the righthand section. The left-hand section of the chamber is somewhat smaller than the right-hand section even when the piston is positioned at the center of the chamber, due to the presence of the piston rod in the left hand section. It is necessary therefore, to provide a storage cavity 17 to compensate for this inequality.

The arrangement is such that when compression occurs, as shown in FIG. 1, oil passes through a spring-biased valve 18 into the storage cavity 17 which surrounds the main chamber, the valve allowing oil to pass in both directions. However, valve 18 is designed to present a higher flow resistance in compression, for then the oil is not discharged through the orifice of the valve but is forced through the narrow gaps of plates. On expansion, the oil which was forced into the storage cavity, flows back into the chamber through the valve orifice without encountering much resistance.

The double-acting exerciser may be used to carry out various exercising functions. For example, for chest expansion, the exerciser is held by an individual across his chest and the tubes are pulled outward. This affords exercise similar to spring-type chest developers, save for the fact that there is a linearity to the stroke yielding a more even and faster development.

This exercise can be varied in its degree of difficulty by the extent to which the arms are extended in front of the body. For this purpose, the inner tube may have graduations inscribed thereon which are readable against the end of the outer tube to provide an indication of the degree to which the tubes are brought together or extended relative to each other. To effect complete tension, the exerciser involves the forearm muscles as well as the biceps and muscles of the chest. Compression builds up muscles in the chest to give increased strength and to improve the chest build.

For forearm development, the exerciser is held with arms straight behind the back and is pulled back and forth. And in shoulder development, the exerciser is held behind the neck and pulled back and forth. Obviously, various exercising positions are possible for individual muscular development and therapy.

The exerciser lends itself to use by couples or teams. Thus for stomach development, two people may sit facing one another with their knees bent and the soles of their feet pushed up against each other. The exerciser is held by one person at each end, with arms straight. The exerciser is then pushed in and out without bending of the arms.

For group exercising, three or more hydraulic elements may be joined in shunt relation to bar type handles at either end, so that a team of people on either end may exercise together. It is also possible to hook one end of an exerciser to an anchor plate. And to exercise by holding the handle and the other end and then alternately pulling away and toward the anchor plate.

While there have been described preferred embodiments of a Double-Acting Hydraulic Exerciser, it will be obvious that many changes and modifications are possible without departing from the essential spirit of the invention.

Claims

What I claim is:

1. A double-acting hydraulic exerciser which in operation is even and free of strain in both tension and traction, said exerciser comprising:

A. inner and outer tubes in telescoping relationship, the inner tube defining a chamber which is oil-filled and encloses a piston, said inner tube having a storage cavity surrounding said chamber and a valve interposed between the chamber and the cavity to allow oil to pass in both directions, said tubes being formed of relatively light weight material incapable of supporting loads substantially beyond that imposed by a human user and having lengths such that when the tubes are fully extended, the distance between handles attached to the ends thereof is substantially equal to the distance between the outstretched hands of a typical user;

B. a piston rod extending between said piston and the end of said outer tube, said piston dividing said chamber into right and left sections and being provided with valves that function alternately to allow oil to pass from the right section to the left section when the tubes are brought together in a compression stroke, and to allow oil to pass from the left section to the right section when the tubes are pulled apart in an expansion stroke, the compression and expansion strokes being linear throughout their lengths; and

C. a pair of hand-grippable handles attached to the ends of said tubes whereby said strokes may be effected manually by said user.

2. An exerciser as set forth in claim 1 wherein the surface of the inner tube is graduated to indicate the extent to which the tubes are pulled apart or brought together.

3. An exerciser as set forth in claim 1 wherein said tubes are made of high-strength plastic material.

4. An exerciser as set forth in claim 1 wherein said tubes are fabricated of aluminum.