Not applicable.
The present invention relates to strength training employing a pair of straps each having an anchor on one end and a hand/foot hold on the other end.
Exercise devices evolving from gymnastics rings and similar rope exercise devices are widely used for strength training. The anchor ends of the device's straps are usually placed above the person performing the exercises, on an exercise bar, a tree limb, or between a door and a door frame. Exercises are then performed using the weight of the body. While the user holds the strap grips only a portion of the weight of the user's body is lifted by keeping the feet or hands on the ground or other support, and moving the user's body toward or away from the vertical plane. By adjusting the length of the straps the angle of the body with respect to the vertical plane is adjusted and thus the strength required for the movement of the body with respect to the vertical plane is also changed. This single exercise apparatus, itself compact and lightweight and thus easily stored and transported, can thus replace an entire set of exercise weights. To change the exercise intensity or to work different muscles it can often be necessary to change the length of the straps during exercise and many devices are known for adjusting the length of a webbing or other straps.
However, prior art mechanisms are such that it is not easy or intuitive to determine how to operate the mechanism so that the strap or webbing can be adjusted as required between exercises. Further, prior art mechanisms can require two hands or the manipulation of a small lever or button which may require some force. The end result is that the strap cannot be kept under some tension during adjustment and so it is not clear, as the adjustment is made, if the result of the manipulation of the strap adjusting mechanism will be the desired one. Typically, in adjusting the straps, the intent is to change the length of two straps by the same amount or to the same length. Thus, adjusting the straps involves using one hand on the grip to keep the strap under at least enough tension so the strap length under tension can be observed, and using the other hand to lengthen or shorten the strap. With the prior art devices this can be difficult to do which leads to repeated and aggravating efforts to accomplish the length adjustments of both straps. What is needed is a simple and intuitive mechanism for adjusting the length of both straps of a strength trainer.
The strength trainer of the invention has a first closed loop of webbing which is attached to a handle. The first closed loop extends around one side of a closed rectangular ring which forms part of a strap adjustment mechanism. The closed rectangular ring has four sides, one opposite the first member and two parallel sides which join the first member and the opposite side. The strength trainer of the invention has a second length of webbing which has one free end attached to an anchor and a second free end which is wrapped around a second member which is mounted between the two parallel sides of the closed rectangular ring and retained on the closed rectangular ring so as to allow some movement of the ring with respect to and along two parallel sides between the first member and the opposite side. The adjustment mechanism has a rigid housing which wraps the opposite side and the two parallel sides and at least part of the first side such that the closed rectangular ring is retained in the housing but can move within the housing toward or away from the part of the housing that wraps the opposite side of the rectangular ring. Two springs which form part of the adjustment mechanism are mounted between the opposite side and the housing so as to bias the rectangular ring toward the part of the housing which wraps the first side. The opposite side of the rectangular ring has a surface facing into the inside of the ring and has a first aggressive surface which faces the second member. The second member has a second aggressive surface facing the first aggressive surface and a third aggressive surface on a side opposite the second aggressive surface. The second length of webbing extends from the anchor and passes through the closed rectangular ring and is wrapped around the third aggressive surface and passes between the first aggressive surface and the second aggressive surface.
The strap adjustment mechanism thus configured employs in part the principle embodied in a capstan about which a rope is wound, by which a person is allowed to hold one end of the rope to resist the movement of a large boat. The clamping force produced by the springs in the housing closes the first aggressive surface and the second aggressive surface against the second web strap, but is easily overcome to make an adjustment in the strap length pulling on the strap. However, under load the second strap wraps the second member over the third aggressive surface to an angle of about 270° which amplifies the spring and increases hold force by eμφ where μ is the coefficient of friction and φ is the total angle of wrap measured in radians. Thus, the hold force is increased by the friction of the third aggressive surface and the wrap angle φ measured in radians. When the second strap is under load i.e., the strength trainer is supporting a person's weight, the tension in the second strap forces the first and second aggressive surfaces together with a force much greater than the force provided by the springs in the housing.
Further objects, features and advantages of the invention will be apparent from the following detailed description when taken in conjunction with the accompanying drawings.
Referring more particularly to
The strap adjustment mechanism, as shown in
The first closed loop of webbing 22 extends around the ring first member 25. The anchor webbing strap 34 has a first free end 36 which is terminated by a closed loop 37 attached to the anchor 38, and a second free end 40 which extends through the adjustment mechanism 28 wrapping around the cross piece second member 42 and is then clipped to the second strap 34 by a clip 68 as shown in
The cross piece second member 42 as shown in
The adjustment mechanism 28 has two coil springs 48 which are mounted to extend between the opposite member 30 and the housing 44 to bias the rectangular ring 26 toward a lower part 50 of the housing which wraps the first member 25. The rear part 62 of the housing 44 has two spring mounting projections 49 which engage the two coil springs 48. The opposite member 30 has two opposed spring mounting projections 51 which engage the other ends of the coil springs 48.
The opposite member 30 of the ring 26 has an internal surface facing the inside of the rectangular ring which forms a first aggressive surface 52 which faces the second member 42. As shown in
As shown in
To adjust the second length of webbing 34 the strap adjustment mechanism is rotated downwardly about 30-90 degrees usually toward the person using the strength trainer as indicated by arrow 71 shown in
To allow assembly of the rectangular ring 26 and the second member 24, the second member may be formed with four flanges 72 which protrude longitudinally from the body 73 of the second member, as shown in
It should be noted that the strap adjustment mechanism 28 does not depend on the housing 44 to support the tension load through the adjustment mechanism.
It should be understood that an aggressive surface means a high friction surface, which for example, has protrusions 60 as shown in
It should be understood that web or webbing or strap refers to strong (e.g., supports loads of hundreds to thousands of pounds) closely woven fabric which has a length which is at least a few times to hundreds of times longer than the width, and a thickness which is less than approximately one tenth of the width.
It is understood that the invention is not limited to the particular construction and arrangement of parts herein illustrated and described, but embraces all such modified forms thereof as come within the scope of the following claims.
This application claims benefit of priority of U.S. App. No. 62/637,241, filed Mar. 1, 2018, the disclosure of which is incorporated by reference herein.
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Number | Date | Country | |
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62637241 | Mar 2018 | US |