Abstract:
Exercising is made more comfortable and effective by providing a foot rest that has a front end which holds the ball of the user&#39;s foot fixed and a back end that both cradles the user&#39;s heel and allows the user to pivot his heel around the ball of his foot in a natural manner. The frame of the machine can be easily and repeatedly taken apart and put back together because it has two arms which mate at a connector that can be mated and unmated by simple pivoting of the two arms.

Description:
This application is a continuation of Ser. No. 08/976,792 filed Nov. 25, 1997. 
    
    
     BACKGROUND OF THE INVENTION 
     This invention relates to exercise machines. 
     The frames of some kinds of exercise machines, e.g., a rowing machine, are made of long, heavy rigid metal pieces which are strong enough to support a seated user and to withstand the forces and motion which occur during exercise. Places are provided on the frame for the user to rest his feet. 
     SUMMARY OF THE INVENTION 
     In the invention, exercising is made more comfortable and effective by providing a foot rest that has a front end which holds the ball of the user&#39;s foot fixed and a back end that both cradles the user&#39;s heel and allows the user to pivot his heel around the ball of his foot in a natural manner. The frame of the machine can be easily and repeatedly taken apart and put back together because it has two arms which mate at a connector that can be mated and unmated by simple pivoting of the two arms. 
     Thus, in general, in one aspect, rowing is made more comfortable and effective by providing a rowing machine in which the footrest has a front end for holding the foot portion of a rower&#39;s foot substantially fixed relative to the frame of the machine, and a back end for cradling the heel of the rower&#39;s foot. The back end is movable relative to the front end to permit the rower to pivot the heel of his foot relative to the front portion of his foot. 
     Implementations of the invention may include the following features. The back end may be a flexible strap that slides in a channel in the front end to permit adjustment for foot length. The adjustment may be enabled by a post in the front end and a series of holes along the length of the strap. The hole fit over the post to fix the position of the back end relative to the front end. 
     The back end of the foot rest may include a cross strap which resists backward sliding of the rower&#39;s foot and which defines a window for receiving the heel of the rower&#39;s shoe. The back end may provide some degree of resistance to pivoting of the rower&#39;s heel. The back end may cradle the rower&#39;s heel against lateral movement. 
     In general, in another aspect, the invention features an exercise machine which is easily stored and set up for use, the machine frame having two beams which mate at a joint configured to allow the two beams to be quickly and repeatedly put together and taken apart. Each beam is supported at an end opposite the joint, and the unsupported end of each beam tends to fall, by force of gravity, about the supported end when the beams are not mated. The joint includes mating mechanical elements on the beams (e.g., a pair of pins and a pair of hooks) which cooperate when mated to lock the unsupported ends to each other to the tendency of the beams to fall. The joint is unlocked by reverse pivoting at least one of the beams about its supported end. 
     Other advantages and features will become apparent from the following description and from the claims. 
    
    
     DESCRIPTION 
     FIG. 1 is a perspective view of a rowing machine. 
     FIGS. 2A,  2 B,  2 C, and  2 D are side views of stages of a rowing cycle. 
     FIG. 3 is a perspective view of a right foot rest. 
     FIGS. 4A and 4B are plan and side elevational views, respectively, of a heel strap. 
     FIG. 5A is a plan view of a toe block. 
     FIG. 5B is a sectional view at  5 B— 5 B in FIG.  5 A. 
     FIG. 5C is an enlarged sectional side view of a portion of the toe block (indicated by a circle in FIG.  5 B). 
     FIGS. 6A and 6B are side elevational and top views, respectively, of left and right foot rests attached to an extension arm. 
     FIGS. 7A,  7 B, and  7 C are diagrammatic side views of a joint structure. 
     FIG. 8 is a perspective view of the rowing machine, disassembled. 
    
    
     A rowing machine  10  (FIG. 1) has a two-piece frame including a hollow, extruded aluminum monorail beam  14  and a hollow angled extruded aluminum extension arm  16 . The beam and the arm are mated at an unsupported quick-release joint  18 . The other end  19  of the beam is supported by a bracket  20 , and the other end  23  of the angled arm  16  is supported by a bracket  22 . A flywheel/fan mechanism  24  is mounted near the bracket end of the angled arm. Cross bars  25 ,  27 , perpendicular to the beams, provide lateral stability. Casters  29  on the front cross bar  27  allow the flywheel section of the rowing machine to be rolled, when the machine is disassembled, for easy transport. A wooden rowing handle  28  with molded rubber grips is connected to the flywheel/far mechanism via a drive cable  26 . A contoured rowing seat  30  glides (arrows  33 ) on rollers  31  along the monorail beam  14 . A pair of foot rests  32 ,  35  are attached on either side of the angled arm near the quick-release joint. 
     The rowing cycle begins (FIG. 2A) with the rower  36  in the catch position. The rower then drives backward by extending his legs and swinging his torso through the vertical position (FIG.  2 B), and finishes the stroke by drawing the handle into his abdomen (FIG.  2 C). The rower then uses his legs to draw his body back (FIG.  2 D), recovering to the catch position. 
     During the drive portion of the cycle the ball of the foot is held fixed relative to the frame of the rowing machine. During recovery the foot is prevented from lifting away from, or sliding laterally relative to, the foot rests. 
     Each foot rest  32  (FIG. 3) includes a support platform  42 , a toe block  44 , a heel strap  46 , and an adjustable anchor strap  48 . The support platform is bent from 8 gauge aluminum or 13 gauge steel, with gussets  50  welded between the two sides  52 ,  54  of the angle iron to brace them. The toe block is fastened to the support platform with nuts and screws  56 . The heel strap passes through a channel  58  (FIGS. 5A,  5 B, and  5 C) under the toe block and out a slot  60  in the front of the toe block. Referring again to FIG. 3, the anchor strap passes through a hole  61  on the inside side of the support platform and surrounds the toe block. It fastens with a buckle  64 , and holds the ball of the rower&#39;s foot securely against the toe block. 
     The heel strap (FIGS. 4A,  4 B) is made from a single piece of semi-flexible, injection molded thermoplastic elastomer such as Santoprene. It has a heel cup  66 , to cradle the rower&#39;s heel, formed by a pair of risers  68  and a curved cross strap  70  connected between the risers. A window  72  is left under the cross strap through which the heel  73  of the rower&#39;s shoe  75  protrudes. 
     A series of cross channels  74  across the width of the bottom of the heel strap, combined with the flexibility of the plastic, allow the heel strap to flex in mid-region  76 . 
     Referring again to FIG. 2A, in the catch position, the rower&#39;s heel  38  tends to “lift” and pivot relative to the ball of the foot  40 . As the rower moves into the catch position and his heel rises from the support platform, the heel of the rower&#39;s shoe catches the bottom surface of the cross strap  70  and carries the heel cup with it. Thus, because the heel strap flexes, the rower&#39;s heel is free to rotate relative to the ball of the foot. 
     Because the heel strap rides with the rower&#39;s shoe, it also provides a small downward restraining force. The restraining force adds to lateral stability of the heel strap and prevents the rower&#39;s foot from rotating out from under the anchor strap  48 . It also gives the rower a sense that his foot is securely held by the foot rest, and helps to simulate the “feel” of the foot restraints found in most rowing shells. 
     The toe block  44  (FIGS. 5A and 5B) is made from a single piece of injection molded plastic such as Polycarbonate. It has a pair of legs  84  which have upper surfaces that curve up at the front, and a toe-rest  86  which bridges the legs. The upward curve is such that, as the rower pushes against the toe-rest to drive himself backward, he applies force more nearly perpendicularly to the foot rest than he would if the toe-rest were not curved, which makes the drive portion of the rowing cycle more efficient. The upward curve also helps to prevent the rower&#39;s foot from sliding forward under the anchor strap  48  so that the ball of the foot stays fixed relative to the frame. 
     The legs  84  and toe rest  86  define the channel  58  through which the heel strap passes. A post base  88  spans the channel at the bottom front of the toe block, blocking a portion of the channel. The front ends  85  of the legs  84 , the bottom of the toe rest, and the post base define the slot  60  through which the heel strap passes to allow adjustment of the length of the foot rest. 
     A pair of 0.375 inch diameter posts  90  extend perpendicularly from the post base in front of the slot  60 . The toe portion  78  (FIG. 4B) of the heel strap has six evenly spaced pairs of 0.400 inch diameter adjusting holes  80  which fit over the posts to prevent the heel strap from sliding. The position of the heel cup, relative to the toe block, is adjusted by lifting the toe portion of the heel strap clear of the posts, sliding the heel strap one way or the other, then pressing the toe portion down so that the posts extend through a different pair of adjusting holes. The top surfaces  92  of the posts are angled (FIG. 5B) to make it easy to adjust the heel strap. 
     The toe rest  86  has a pair of ribs  94 ,  96  on its bottom surface which strengthen the toe rest. The toe portion of the heel strap has a tapered overlap portion  82  which extends forward from its upper surface. The overlap portion butts up against the front rib  96 , when the heel strap is fully extended, to prevent the heel strap from being pulled out from under the toe block (FIG.  5 C). 
     The foot rests  32  are attached (FIGS. 6A and 6B) to the frame at the joint end of the extension arm  16  with bolts  98 . A pair of joint pins  102 ,  104  (FIGS. 7A,  7 B,  7 C) are bolted through the foot restraints, and a pair of hooks  106 ,  108  are bolted to the upper and lower surfaces of the monorail beam  14 , facing in opposite directions. 
     The monorail beam and the angle arm are mated by inserting the joint end of the monorail between the foot restraints, hooking the lower joint pin  104  with the lower hook  108 , and rotating the monorail beam relative to the extension arm until the upper hook  106  engages the upper joint pin  102 . Because the joint is unsupported, the two beams tend to rotate towards each other about their respective support brackets  20 ,  22  as shown by arrows  110 ,  112 . The joint pins and hooks are configured to resist this rotation and hold the rowing machine in its assembled configuration. The two beams are easily disconnected, however, simply by lifting up on the joint  18  and rotating the beams apart from each other. 
     For storage (FIG.  9 ), the monorail beam stands upright on its bracket end. The angle arm is pivoted around its bracket until the casters  29  rest on the floor. The angle arm may be moved around on the casters to a storage location and than rested on the flywheel/fan mechanism. 
     Other embodiments are within the scope of the following claims. For example, the foot restraint structure and the quick-release joint could be used in other exercise equipment, e.g., recumbent exercise bicycles.