Patent Publication Number: US-6702724-B2

Title: Hamstring exercise machine

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to the field of exercise equipment. More specifically the present invention relates to an exercise machine for exercising the hamstrings, the machine having at least one movement resistance weight and a weight support surface positioned below the weight, a weight displacement pedal slidably mounted to an upright pedal guide shaft, a machine frame and a pulley rotatably mounted on a pulley axle secured relative to the machine frame at a position above the at least one lifting weight and also above the weight displacement pedal, a cable having a cable distal end secured to the weight and having a cable proximal end secured to the weight displacement pedal, the cable being of a length relative to the elevation of the pulley such that when the weight is resting on the weight support surface the pedal is elevated above its rest position. The pedal preferably includes a pedal brake biased with brake engagement biasing means which engages the pedal guide shaft when at rest and which releases the pedal guide shaft upon application of downward force to the pedal against the biasing of the brake engagement biasing means, so that when the pedal is released, the brake engages the pedal guide shaft and prevents the weight from falling. 
     2. Description of the Prior Art 
     There have long been weight machines for exercising various muscles of the human body. Many of these have included stacks of discrete and separable weight plates, any desired number of which can be lifted by means of levers or pulleys. A problem with these prior machines has been that none have been suited to exercising the hamstrings and the muscles to which the hamstrings connect. Another problem has been that a sudden release of the weight plates causes the plates to fall freely and crash into plates or a support structure below the stack, causing potential damage to the machine, to the gym floor, and to the user if the falling weight plates should cause a pedal or grip to fly into high impact contact with his or her body. 
     It is thus an object of the present invention to provide an exercise machine which is configured to permit full range exercise of the hamstrings. 
     It is another object of the present invention to provide such an exercise machine which includes weight stack brake means to prevent suddenly released raised weight plates from falling and crashing into a plate or structure below the raised plates, and the resulting sudden displacement of pedals and grip handles. 
     It is still another object of the present invention to provide such an exercise machine which is compact and readily transported. 
     It is finally an object of the present invention to provide such an exercise machine which is safe, reliable, simple in construction and relatively inexpensive to manufacture. 
     SUMMARY OF THE INVENTION 
     The present invention accomplishes the above-stated objectives, as well as others, as may be determined by a fair reading and interpretation of the entire specification. 
     An exercise machine is provided for exercising the hamstrings, including at least one weight; a weight support surface below the weight; an upright weight guide shaft laterally spaced apart from the weight; a weight displacement pedal slidably mounted to the pedal guide shaft; a machine frame; a generally horizontal pulley axle secured to the machine frame at a position higher than the weight and higher than the weight displacement pedal and laterally between the weight and the pedal guide shaft; a pulley mounted on the pulley axle so that the pulley is rotatable relative to the machine frame; a cable extending over and riding on the pulley and having a cable distal end secured to the weight and having a cable proximal end secured to the weight displacement pedal, the cable being of a length so that when the weight rests on the weight support surface the weight displacement pedal is elevated. 
     The exercise machine preferably additionally includes a pedal brake positioned adjacent to the pedal guide shaft and biased with a brake engagement biasing mechanism to engage the pedal guide shaft and including a brake disengagement mechanism operatively connected to the pedal which releases the pedal guide shaft upon application of downward force on the weight displacement pedal against the biasing of the brake engagement biasing mechanism. The machine frame preferably includes a parallelepipped structure having a generally horizontal rectangular base frame, a generally horizontal rectangular top frame spaced above the base frame and laterally spaced apart upright frame posts interconnecting the base frame and the top frame. The frame posts preferably include a first proximal frame post and a first distal frame post and a second proximal frame post and a second distal frame post. The exercise machine preferably additionally includes a first pulley mounting member interconnecting and secured to the first proximal frame post and the first distal frame post, and a second pulley mounting member interconnecting and secured to the second proximal frame post and the second distal frame post, where the pulley axle extends between and is secured relative to the first pulley mounting member and the second pulley mounting member and passes through the center of the pulley, the pulley being positioned between the first pulley mounting member and the second pulley mounting member. 
     The pedal guide shaft preferably extends between and is secured to the base frame and the top frame. The at least one movement resistance weight preferably includes a weight guide port and is slidably mounted on an upright weight guide shaft extending through the weight guide port, the weight guide shaft extending between and being secured to the base frame and the top frame. The at least one movement resistance weight preferably includes a stack of discrete and separable weight plates and an upright plate engaging rod connected the cable distal end and having a longitudinal series of weight key passing holes, the engaging rod extending through registering engaging rod ports in the weight plates, and a weight key fitted underneath a given number of the weight plates selected for lifting in a given workout and into a corresponding engaging rod port. The exercise machine preferably additionally includes a housing cover fitted over the machine frame upper end and around the pulley to protect a user from injurious contact with the pulley and the cable. 
     The exercise machine preferably additionally includes a substantially horizontal base plate resting on the ground beneath the pedal, and base plate legs secured to the base plate and extending upwardly, and leg brackets connecting the base plate legs to two opposing frame posts. 
     The exercise machine preferably still additionally includes first and second grip handles secured relative to and extending from the frame upper end, above the weight displacement pedal. The exercise machine preferably still additionally includes a first grip arm connected to the first grip handle and a second grip arm connected to the second grip handle, the first and second grip arms extending forwardly from the frame; first and second grip arm support structures including a structure for receiving and slidably passing the first and second grip arms respectively and including a structure for securing the first and second grip arms at any of various forward extensions. 
     Each grip arm preferably includes a longitudinally extending grip arm keyway and wherein each grip arm support structure includes a grip arm key which fits into the corresponding the grip arm keyway for preventing rotation of each grip arm about its longitudinal axis while permitting each grip arm to slide longitudinally within the corresponding grip arm support structure. 
     The weight displacement pedal preferably includes a tubular pedal support arm formed of telescoping proximal and distal pedal support arm segments, where the weight displacement pedal is secured to the proximal pedal support arm segment and the cable proximal end is secured to the distal pedal support arm segment, the pedal distal support arm segment including a pedal guide tube slidably fitting around the pedal guide shaft, and including a mechanism for releasibly securing the proximal pedal support arm segment relative to the distal pedal support arm segment. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Various other objects, advantages, and features of the invention will become apparent to those skilled in the art from the following discussion taken in conjunction with the following drawings, in which: 
     FIG. 1 is a perspective side view of the preferred embodiment of the exercise machine. 
     FIG. 2 is a front view of the exercise machine of FIG.  1 . 
     FIG. 3 is a perspective rear view of the machine of FIG.  1 . 
     FIG. 4 is a view as in FIG. 3 with the housing cover removed. 
     FIG. 5 is a side view of the machine of FIG. 4, revealing details of the pulley and cable structures. 
     FIG. 6 is a perspective top view of the machine of FIG.  4 . 
     FIG. 7 is a perspective side view of the machine of FIG. 4, showing the weight displacement pedal depressed and the weight stack lifted by the cable. 
     FIG. 8 is a side view of the machine of FIG. 7, once again showing the weight stack elevated. 
     FIG. 9 is side view as in FIG. 8 with the weight stack lowered to its rest position and the pedal elevated to its rest position. 
     FIG. 10 is a side view as in FIG. 9, showing the pedal arm telescoped to a contracted configuration. 
     FIG. 11 is a side view as in FIG. 10, with the weight stack elevated and secured in its elevated position by the machine brake. 
     FIG. 12 is a perspective view of the machine positioned as in FIG.  11 . 
     FIG. 13 is a view as in FIG.  12 . 
     FIG. 14 is a perspective exploded view of the apparatus, revealing its various operational elements and their spacial relationships. 
     FIG. 15 is a perspective view of the horizontal base plate. 
     FIG. 16 is broken away side view of the inventive pedal portion of the brake engagement biasing means of the brake mechanism. 
     FIG. 17 is a detailed, perspective view of the elements making up the brake mechanism. 
     FIG. 17 a  is a partial view of the machine frame, showing pedal guide shaft engaging elements of the brake mechanism. 
     FIG. 18 is a front perspective view of the machine frame and the base plate legs and leg brackets. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention which may be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriately detailed structure. 
     Reference is now made to the drawings, wherein like characteristics and features of the present invention shown in the various FIGURES are designated by the same reference numerals. 
     First Preferred Embodiment 
     Referring to FIGS. 1-18, an exercise machine  10  is disclosed for exercising the hamstrings, the machine  10  having at least one movement resistance weight  12  and a weight support surface  14  below the weight  12 , a weight displacement pedal  20  slidably mounted to an upright pedal guide shaft  22 , a machine frame  30  and a pulley  32  rotatably mounted on a pulley axle  34  secured to the machine frame  30  at a position above the lifting weight  12  and above the weight displacement pedal  20 , a cable  60  extending over and riding on pulley  32 , having a cable distal end  62  secured to the weight  12  and having a cable proximal end  64  secured to weight displacement pedal  20 , the cable  60  being of a length relative to the elevation of pulley  32  such that when the weight  12  is resting on weight support surface  14  the pedal  20  is elevated. The pedal  20  preferably includes a pedal brake  70  biased with brake engagement biasing means  72  which engages the pedal guide shaft  22  when pedal  20  is at rest, and which releases the pedal guide shaft  22  upon application of downward force onto pedal  20  against the biasing of the brake engagement biasing means  72 . 
     Machine frame  30  preferably includes a parallelepipped structure having a generally horizontal rectangular base frame  36 , a generally horizontal rectangular top frame  38  spaced above base frame  36  and four upright frame posts interconnecting the corners of base frame  36  and top frame  38 . The frame posts include a first proximal frame post  42  and a first distal frame post  44  and a second proximal frame post  46  and a second distal frame post  48 . The members making up machine frame  30  are preferably tubular for reduced machine  10  weight. A first pulley mounting member  52  extends from the first proximal frame post  42  to the first distal frame post  44  and a second pulley mounting member  54  extends from the second proximal frame post  46  to the second distal frame post  48 . The pulley axle  34  extends between and is secured to the first and second pulley mounting members  52  and  54 , respectively, and through the center of pulley  32  which is positioned between first and second pulley mounting members  52  and  54 . The pedal guide shaft  22  is preferably circular in cross-section and extends between and is secured to the base frame  36  and to the top frame  38 . 
     The weight  12  preferably has two weight guide ports  16  and is slidably mounted on two preferably spaced apart, upright first and second weight guide shafts  56  and  58  extending through weight guide ports  16 . The first and second weight guide shafts  56  and  58  extending between and are secured to first and second sides of the base frame  36  and the top frame  38 . The weight  12  is preferably of stack of discrete weight plates  12 , any desired number of which are selectable and can be isolated for lifting independently of any remaining weight plates  12 . In this instance, cable distal end  62  is connected to an upright weight engaging rod  82  having a longitudinal series of weight key passing holes  84 , the engaging rod  82  extending through an engaging rod port  86  in each weight plate  12 , and a weight key  92  is fitted underneath the number of weight plates  12  selected for a given workout and into a corresponding engaging rod port  86 , in a well-known configuration. A housing cover  94  is preferably fitted over the machine frame  30  upper end and around the pulley  32  to protect a user from injurious contact with machine  10  moving parts. 
     A substantially horizontal base plate  102  preferably rests on the ground G beneath the pedal  20  and is secured to first and second base plate legs  104  and  106  extending upward to leg brackets  112  and  114  connecting the base plate legs  104  and  106  to first and second proximal frame posts  42  and  26 , respectively. Each base plate leg  104  and  106  is preferably tubular and has an upper end cap  108 . A strut  116  extends between and connects the base plate legs  104  and  106  to enhance structural integrity. 
     First and second upright grip handles  122  and  124  preferably extend forwardly from the frame  30  upper end, above the pedal  20  on grip arms  126  and  128  which slidably pass through correspondingly located first and second leg brackets  112  and  114 , for a machine  10  user to hold and brace himself or her self while pressing downwardly with a foot against the weight displacement pedal  20 . Each grip arm  126  and  128  has a longitudinal guide keyway  132  into which a frame key  134  passes so that the grip arms  126  and  128  can slide forwardly and rearwardly but cannot rotate about their axes relative to the leg brackets  112  and  114 , so that the grip handles  122  and  124  do not pivot out of their upright orientations. A grip arm pin screw  136  passes through each leg bracket  112  and  114  and releasibly enters any one of a longitudinal series of grip arm pin ports  142  in the corresponding grip arm  126  or  128  to secure the grip arm at a desired forward extension against longitudinal sliding during machine  10  use. 
     The pedal  20  preferably includes a tubular pedal support arm  24  formed of telescoping proximal and distal pedal support arm segments  24   a  and  24   b , respectively. The pedal  20  is secured to the proximal pedal support arm segment  24   a  and the weight cable proximal end  64  is secured to the distal pedal support arm segment  24   b . The pedal  20  is preferably mounted to the pedal support arm  24  on a horizontally oriented pin  20   a  so that the pedal  20  is pivotable forwardly and rearwardly to any of several tilt positions relative to horizontal, and the pedal  20  is releasibly securable in each of these tilt positions with a set screw or other well known mechanical means to alter the nature of the exercise. The distal pedal support arm segment  24   b  includes a pedal guide tube  26  which slidably fits around the pedal guide shaft  22 . 
     The pedal brake  70  preferably includes a brake arm pivot pin  74  about which first and second brake arms  76  and  78 , respectively, pivot away from and into contact with opposing sides of the pedal guide shaft  22 . See FIGS. 16,  17  and  17   a . A spring  66  biases the brake arm free ends toward each other and into gripping contact with the pedal guide shaft  22 , and the free end of each brake arm  76  and  78  has a brake pad P oriented toward the pedal guide shaft  22 . A brake cable  80  having a cable sleeve  80   a  passes through a sleeve mount  96  secured to a brake arm extension  76   a  of the first brake arm  76  and is secured to a brake cable mount  98  secured to the second brake arm  78 . Pressing the weight displacement pedal  20  causes the brake cable  80  to be pulled back into the cable sleeve  80   a  and thus lengthens the free length of the brake cable  80 . This releases any biasing force on the brake pads P. In the rest state, the brake cable  80  is pulled away from the sleeve  80   a  by the spring  66  and the swing rod  88 . 
     To use exercise machine  10 , one simply faces machine  10 , grips the grip handles  122  and  124  with each hand, places one foot onto the pedal  20 , and presses pedal  20  downwardly against the resistance of the lifting of the weight(s)  12  and then raises his or her foot and the pedal  20 , and repeats this cycle as many times as desired for one set of repetitions (“reps”). Then the user places his or her other foot on the pedal  20  and repeats this method. The user foot not on pedal  20  preferably rests on top of base plate  102  during machine use. 
     While the invention has been described, disclosed, illustrated and shown in various terms or certain embodiments or modifications which it has assumed in practice, the scope of the invention is not intended to be, nor should it be deemed to be, limited thereby and such other modifications or embodiments as may be suggested by the teachings herein are particularly reserved especially as they fall within the breadth and scope of the claims here appended.