Exercise machines having alternating reciprocating foot supports configured to traverse or travel about a closed path to simulate a striding, running, walking, and/or a climbing motion for the individual using the machine are well known in the art, and are commonly referred to as elliptical exercise machines or elliptical cross-trainers. In general, an elliptical or elliptical-type exercise machine comprises a pair of reciprocating foot supports designed to receive and support the feet of a user. Each reciprocating foot support has at least one end supported for rotational motion about a pivot point or pivot axis, with the other end supported in a manner configured to cause the reciprocating foot support to travel or traverse a closed path, such as a reciprocating elliptical or oblong path or other similar geometric outline. Therefore, upon operation of the exercise machine to rotate the proximal end, each reciprocating foot support is caused” to travel or traverse the closed path. The reciprocating foot supports are configured to be out of phase with one another by 180° in order to simulate a proper and natural alternating stride motion.
An individual may utilize an elliptical or elliptical-type exercise machine by placing his or her feet onto the reciprocating foot supports. The individual may then actuate the exercise machine for any desired length of time to cause the reciprocating foot supports to repeatedly travel their respective closed paths, which action effectively results in a series of strides achieved by the individual to obtain exercise, with a low-impact advantage. An elliptical or elliptical-type machine may further comprise mechanisms or systems for increasing the resistance of the motion, and/or for varying the vertical elevation or height of the closed path. In addition, the reciprocating motion of the feet to achieve a series of strides may be complemented by a reciprocating movement of the arms, whether assisted by the exercise machine via a suitably configured mechanism or system, or unassisted.
A typical closed path may comprise a generally horizontal outline having a longitudinal axis therethrough. Depending upon the exercise machine, a closed path may be many different sizes. As such, a particular measurement of interest to individuals with respect to an elliptical or elliptical-type exercise machine is “stride length”. A stride length is essentially a measurement of the distance separating the two furthest points along the longitudinal axis of the closed path. Therefore, upon actuation of the exercise machine, a single stride may be referred to as travel by the reciprocating foot support, and therefore the foot of a user, along the closed path from a first endpoint on the along the longitudinal axis of the closed path to the a distal endpoint, also on the longitudinal axis. The stride and resulting stride length provided by an exercise machine, although simulated and possibly modified, is comparable to a single stride achieved during natural and/or modified gait of an individual.
Obviously, the strides, and particularly the stride lengths, between different individuals may vary, perhaps considerably. Indeed, a person of small stature will most likely have a much shorter stride length than a person of large stature, and thus will be more comfortable on an exercise machine configured to accommodate his or her particular size and resulting stride length. As such, it is important that the exercise machine function with a stride that corresponds to the stride of the user. The challenge arises when the exercise machine is intended for use by many individuals that may or may not have the same stride length. Moreover, it may be desirable within an exercise routine to vary the speed or frequency of strides along the closed path, the resistance felt, and/or the vertical height of the closed path, wherein some or all of these variable elements may require the user to adapt his or her stride to the changing routine to realize a more natural motion.
Despite their many advantages, and despite recent efforts to attain such, elliptical or elliptical-type exercise machines are devoid of a simple and efficient way to vary their stride length for the purpose of accommodating the stride lengths of individuals of different size and of providing a more natural stride motion. Many prior related exercise machines exist in the art that comprise complex or intricate solutions. However, many of these are difficult to operate at best, and are also expensive to manufacture and cumbersome to assemble as many of them comprise several components or linkages to ultimately achieve a variable stride length.
Another inherent deficiency with the many prior related exercise machines comprising a mechanism or system for varying the stride length of the machine is that they are so complex in design that it would be difficult to utilize the system or mechanism technology on different machines without requiring significant modifications to the machine, if possible at all.