1. Field of the Invention
The present general inventive concept relates to an exercise apparatus resistance unit, and more particularly, to an exercise apparatus resistance unit that is provided with resilient flexural tubes to provide resistance to a user.
2. Description of the Related Art
application Ser. No. 10/370,975 relates to a resistance unit having one or more pulleys on each end. One or more cables are provided across the pulleys and the resistance unit. A force is applied to either end of the cables to deflect the resilient panel. The resistance unit can be a resilient panel or tubular structural members. In addition, the resilient panel can be reinforced with the tubular structural members.
The force applied to the resilient panel through the pulleys provides a bending force to bend the resilient panel. The resilient panel has an original orientation, an elastic resistance, and an elastic memory so that the resilient panel bends from the original orientation when the bending force and a compressive load is applied and where the elastic memory allows the resilient panel to substantially return to the original orientation when the bending force is removed. The pulleys are located at each end of the resilient panel, and are arranged so that the respective pulleys on each end of the resilient panel share the same axis of rotation and are each offset from the plane of the resilient panel. The cable runs from pulley to pulley in a tackle arrangement where each end of the cable emerges from a pulley at the other end of the resilient panel, so that when the ends of the cable are pulled, resistance is generated by applying the bending moment and the compressive load to the opposing ends of the resilient panel. The resilient panel has an adjustable level of resistance.
application Ser. No. 10/351,307 relates to sports equipment having a tubular structural member. The tubular structural member can have variable resistance with respect to a bending plane of the tubular structural member.
Prior art exercise equipment have other methods to convert a free weight or other free standing methods of resistance into a useful means of resistance for exercise equipment. Resistance is achieved by providing a mechanical advantage to lower the mass required. U.S. Pat. No. 4,072,309 teaches the use of a circular elastic cord to provide resistance. U.S. Pat. No. 5,603,678 includes elastomeric weight straps in addition to the use of dead weight as a resistance device. U.S. Pat. No. 4,620,704 and U.S. Pat. No. 4,725,057 each teaches the use of resilient rods as a means of providing resistance.
Other examples of the prior art include resistance devices based on hydraulic systems such as those described in U.S. Pat. No. 3,834,696 and U.S. Pat. No. 4,148,479. U.S. Pat. No. 3,955,655 teaches fluid based resistance exercise devices. Similarly, U.S. Pat. No. 3,944,221 teaches resistance methods based on the use of air cylinders. U.S. Pat. No. 4,333,645 and U.S. Pat. No. 3,638,941 each teaches the use of springs as resistive devices.
Another consideration for the design of exercise machines is the ability to change the level of resistance to suit the particular user and the exercise being performed. When a dead weight method of resistance is used the user must stop the exercise routine to change the amount of weight desired. In the simplest, barbell type system, this requires the user to stop the exercise and physically affix or remove the dead weight on the bar before resuming his workout. Prior art, such as U.S. Pat. No. 3,647,209 teaches a system of cables, pulleys and deadweight to achieve resistance, whereby the movement of pins engages or disengages the desired weights onto the lifting device. However, this type of system also requires that the user stop the exercise and frequently move to a new position to affect the change in weight resistance.
U.S. Pat. No. 4,072,309 adjusts the level of resistance in an exercise apparatus through elastomeric weight straps which requires the user to also stop the exercise and physically move to a new position to affect the change in weight resistance by changing the elastic band and/or adding or removing auxiliary dead weights.
The resilient rod method of resistance as found in U.S. Pat. No. 4,620,704 and U.S. Pat. No. 4,725,057 require the user to also stop the exercise and physically move to a new position to affect the change in weight resistance by changing the number or type of resistance rods that are connected by cable to the exercise apparatus. It is therefore inconvenient for the user to effectively adjust the resistance of the exercise apparatus.