Abstract:
A weightlifting apparatus having free weight simulation and a safety mechanism includes at least one upright support having a bar engaging pulley assembly and a weight engaging pulley assembly. The upright support includes a universal joint for allowing the upright support to pivot. A lifting bar having an end movably coupled to the bar engaging pulley assembly is also included. The lifting bar includes a grip portion having switch contact disposed therein that is engaged when the grip portion is depressed. A clutch assembly is provided for enabling the bar engaging pulley assembly and weight engaging pulley assembly to move together in unison when a voltage is supplied by engaging the grip portion. Disengagement of the grip portion opens the switch contact and causes voltage to be cut off from the clutch assembly, thereby disengaging the weight support element and the lifting bar.

Description:
FIELD OF THE INVENTION 
       [0001]    In general, the invention relates to a weightlifting apparatus and more particularly to weight lifting apparatus that simulates a free weight barbell while providing a safety mechanism that disengages the weight load when a user releases a grip on the lifting bar. 
       BRIEF SUMMARY 
       [0002]    A weightlifting apparatus having free weight simulation and a safety mechanism includes at least one upright support having a bar engaging pulley assembly and a weight engaging pulley assembly. The upright support includes a universal joint for allowing the upright support to pivot about a base. The weightlifting apparatus also includes a lifting bar support element coupled to the lifting bar engaging pulley assembly. A lifting bar having an end coupled to the bar engaging pulley assembly is also included. The lifting bar includes a grip portion having switch contact disposed therein that is engaged when the grip portion is depressed. A bar end is coupled to the lifting bar support element with a spherical bearing that enables horizontal, vertical and rotational movement of the lifting bar. 
         [0003]    The weightlifting apparatus also includes a weight support element coupled to the weight engaging pulley assembly, wherein the weight support element is adapted to hold weights. The weightlifting apparatus also includes a clutch assembly for enabling the bar engaging pulley assembly and a weight engaging pulley assembly to move together in unison when a voltage is supplied by engaging the grip portion. Disengagement of the grip portion opens the switch contact and causes voltage to be cut off from the clutch assembly, thereby uncoupling the lifting bar engaging pulley assembly and weight engaging pulley assembly and disengaging the weight support element and the lifting bar. 
         [0004]    In one embodiment, the clutch assembly includes a clutch coil and a pair of clutch plates that contact to enable the bar engaging pulley assembly and weight engaging pulley assembly to move together in unison and separate to uncouple the lifting bar engaging pulley assembly and weight engaging pulley assembly, thereby disengaging the weight support element and the lifting bar. The weightlifting apparatus also includes a lifting bar guide rod and a weight support guide rod. The lifting bar support element is a bracket having a sleeve for fitting over lifting bar guide rod and a slot for coupling to lifting bar engaging pulley assembly and where the a weight support element is a bracket having a sleeve for fitting over weight support guide rod and a slot for coupling to weight engaging pulley assembly. Further, the weightlifting apparatus may include a base coupled to the upright support by the universal joint, wherein a base ring is coupled to the base and a restrictor ring is coupled to the upright support adjacent to the universal joint. The restrictor ring and base ring are positioned above and below the universal joint to limit the allowable horizontal movement of the lifting bar and to keep the upright support in a generally upright position. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0005]      FIG. 1A  is a perspective view of a weightlifting apparatus in accordance with an embodiment of the invention and  FIG. 1B  is an enlarged view of a lifting bar support element and weight support element. 
           [0006]      FIG. 2  is a cross sectional view of a lifting bar. 
           [0007]      FIG. 3  illustrates a lengthwise cross-sectional view of the lifting bar. 
           [0008]      FIG. 4  is a wiring schematic of a safety mechanism for use with the weightlifting assembly. 
           [0009]      FIG. 5  is an exploded view of an electromagnetic clutch. 
           [0010]      FIG. 6  is a partial view of a pulley system for the weightlifting apparatus. 
           [0011]      FIGS. 7A and 7B  are assembled and exploded views of upright supports of the weightlifting assembly. 
           [0012]      FIGS. 8A-8C  illustrate top, back and side views of the weightlifting apparatus with the upright structures in pivoted positions. 
           [0013]      FIG. 9A  illustrates the weightlifting apparatus with the upright structures in pivoted positions.  FIGS. 9B and 9C  show enlarged views of base and bar pivoting mechanisms. 
           [0014]      FIG. 10A  is a perspective view of the weightlifting apparatus with the weights in an engaged state with enlarged views of a grip rail switch ( 10 B) and clutch assembly ( 10 C). 
           [0015]      FIG. 11A  is a perspective view of the weightlifting apparatus with the weights in a disengaged state with enlarged views of a grip rail switch ( 11 B) and clutch assembly ( 11 C). 
       
    
    
     DETAILED DESCRIPTION 
       [0016]    A weightlifting apparatus  10  is provided for safely performing a weight lifting exercises, such bench press, without a spotter present to provide assistance if the person doing the exercise is unable to complete a lift or losses control of the weight during the lift. Weightlifting apparatus  10  also simulates a free-weight barbell by allowing independent motion of the lifting bar both vertically and horizontally from end to end. 
         [0017]      FIG. 1  illustrates weightlifting apparatus  10  in accordance with an embodiment of the invention with an enlarged view of a weightlifting safety mechanism  15 . The weightlifting apparatus  10  has a base  18  with a bench  19  and a pair of upright structures, each of which is indicated at  20 . A lifting bar  22  is positioned between and coupled to the upright structures  20 , Each upright structure  20  includes a pivoting mechanism  25 , such as a universal joint.  FIG. 1A  illustrates weightlifting apparatus  10  in an active position. Weights  30  are positioned on weight mounting posts  32  supported by weight mounting support elements  33 . In operation, a user lightly grips lifting bar  22  and moves it into a desired start position. Lifting bar  22  is attached at each end to a lifting bar support element  35  by means of a spherical bearing assembly. This allows the lifting bar to have independent movement at each end and allows the lifting bar to rotate 360 degrees for ideal positioning of the grip rail to hand position. Lifting bar  22  includes a grip rail  38  for engaging weights  30 . Lifting bar  22  moves up or down freely if grip rail  38  has not been depressed. 
         [0018]      FIG. 2  an end cross-sectional view of lifting bar  22 . As shown in  FIG. 3 , when a user is ready to lift weights  30 , the user tightens their grip on lifting bar  22 , thereby squeezing grip rail  38  towards the surface of lifting bar  22 . Grip rail  38  includes a grip engaging portion  40  and a plunger contacting portion  42  with a neck  44  therebetween. Grip rail  38  fits within a slot or opening in an upper side of lifting bar  22  as shown in  FIG. 3 . When grip rail is depressed towards the surface of lifting bar  22 , plunger contacting portion  42  engages switch plungers  48 . Thus, switch contacts  50  are connected and voltage is applied to clutch assembly  55 , which connects lift bar  22  to weights  30 . As is evident, the lifting bar, which is effectively weightless, can be moved with a partial grip. A tight grip on the bar will depress the grip rail  38  applying pressure to the switch plunger depressing it. 
         [0019]      FIG. 3  illustrates a lengthwise cross-sectional view of lifting bar  22 . As shown, when plunger  48  is depressed, electrical contacts within switches  50  at each end of the lifting bar are connected and as illustrated in the wiring schematic of  FIG. 4 . Connecting switch contacts  50  applies voltage to an electrical relay that applies voltage to clutch coils  70 . A stepdown transformer  52  is utilized to keep low voltage to lifting bar area. At this time, lifting bar  22  is effectively attached to the weights simulating a conventional free-weight barbell. When a user relaxes the grip on lifting bar  22 , grip rail  38  extends to remove the electrical connection within switches  50 . Therefore, the circuit is opened and clutch plates are allowed to separate and the weights are disconnected from lifting bar  22 . Additionally, if clutch plates  71  and  72  become mechanically bound and can&#39;t separate, lifting bar  22  with the weights still effectively connected would drop down to their original starting position, thereby preventing harm to a user. 
         [0020]    If a user is unable to complete a lift or control is lost, relaxing the grip on lifting bar  22  allows grip rail  38  to extend. When grip rail  38  is extended, pressure removed from plungers  48 , thereby opening contacts  50  and removing voltage to clutch coils  70 . Clutch plates  71  and  72  are then separated and weights are disconnected from lifting bar  22 . The weights then drop to their start position. At this point, or if the exercise is complete, the user can move lifting bar  22  up and back to allow ease of exiting from the bench. 
         [0021]    In the embodiment shown in  FIGS. 5-6 , clutch assembly  55  is an electro-magnetic clutch. Clutch assembly  55  includes two pulleys  60   a  and  60   b  with belts  62   a  and  62   b  extending upward to two additional pulleys  64   a  and  64   b  at the top of the assembly. Also extending from bottom to top are two sleeves  66   a  and  66   b  attached to weight mounting support element  33  and the lifting bar support element  35 , respectively. Weight mounting support element  33  includes a receiving slot  68   a  for coupling to belt  62   a  and lifting bar support element  35  includes a corresponding receiving slot  68   b  for coupling to belt  62   b.    
         [0022]    Clutch assembly  55  includes a coil of wire  70  and two clutch plates  71  and  72 . Clutch plate  71  is on the same sleeve as pulley  60   a  moving its associated belt  62   a  and support element  33 . Clutch plate  71  is on a separate sleeve attached to pulley  60   b  moving its associated belt  62   b  and lifting bar support element  35 , as illustrated in  FIG. 5 . In an un-activated position, pulley  60   a  and belt  62   a , which are coupled to weight support element  33  and weights move separately from pulley  60   b  and belt  62   b , which are coupled to lifting bar support element  35  and lifting bar  22 . When voltage is applied to clutch coil  70 , a magnetic field is created that pulls clutch plates  71  and  72  together such that clutch plates  71  and  72  act as one combined unit. Movement of lifting bar  22  then causes a corresponding movement of weights  30 . If the voltage is removed from clutch coil  70 , clutch plates  71  and  72  separate and gravity lowers weights  30  and weight support element  33  back to a bottom starting position. Thus, lifting bar  22 , being free of weights, can be positioned wherever desired. Lifting bar  22  stays in whatever location it is placed because a matching counter-weight  75  to the weight of the lifting bar bracket and lifting bar is attached to an opposite side of belt  62   b , thereby creating a generally weightless lifting bar. 
         [0023]      FIGS. 7A and 7B  illustrate assembled and exploded views of upright structure  20 , one of which is positioned at each end of weightlifting apparatus  10 . Each upright structure  20  includes at least two guide rods  80   a  and  80   b . Each guide rod  80   a ,  80   b  is attached to a bracket  81  and restrictor ring  82  at a bottom end and wheel mounting bracket  84  at a top end. Lifting bar support element  35 , which includes sleeve  66   b  fits over lifting bar guide rod  80   b  such that lifting bar support element  35  can slide vertically along guide rod  80   b . Similarly, weight mounting support element  33 , which includes sleeve  66   a , fits over weight support guide rod  80   a  such that weight mounting support element  33  can slide vertically along weight support guide rod  80   a . Belts  62   a  and  62   b  are coupled to lower pulleys  60   a  and  60   b  and upper pulleys  64   a  and  64   b.    
         [0024]    As shown in  FIGS. 8A-8C , weightlifting apparatus  10  includes an upright structure  20  on each end supporting lifting bar  22 . Upright structures  20  pivot relative to base  18  by way of a pivoting mechanism  25 .  FIGS. 8A-8C  illustrate top, back and side views of weightlifting apparatus  10  with upright structures  20  in pivoted positions. The pivoting movement of upright structures allows lifting bar  22  to move in a manner similar to a free weight barbell. 
         [0025]      FIG. 9A  illustrates weightlifting apparatus  10  with upright structures  20  in pivoted positions. An enlarged view of pivoting mechanism  25  is shown in  FIG. 9B . A restrictor ring  82  is coupled to each upright structure  20 . Similarly, a base ring  85  is coupled to each end of base  18 . Thus, restrictor ring  82  and base ring  85  are positioned above and below pivoting mechanism  25  to limit the allowable horizontal movement of lifting bar  22  and to keep upright structures  20  in a generally upright position. 
         [0026]    In addition, lifting bar  22  is capable of swiveling or pivoting with respect to lifting bar support element  35 .  FIG. 9C  is an enlarged view of a joint such as a swivel joint  87  which allows for pivoting movement of lifting bar  22  when upright structures  20  pivot from their upright position. The joint may also be a spherical bearing that enables horizontal, vertical and rotational movement of the lifting bar. 
         [0027]      FIG. 10A  illustrates an additional back view of weightlifting apparatus  10  in an engaged position, such as during an active lift.  FIG. 10B  is a detailed view of grip rail  38  in a depressed position. When grip rail is depressed, switch  50  contacts are closed. A switch  50  is positioned on each end of lifting bar  22 . When both switches  50  are activated clutch assemblies  55  are activated. A detailed view of one of clutch assemblies  55  in an activated is shown in  FIG. 10C . If one or both of switches  50  are released, both clutch assemblies  55  will be deactivated. Lifting bar  22  is capable of rotating to any position that is comfortable for a user to complete a lift and to locate grip rail  38  at a convenient position. As shown in  FIG. 10C , activation of switches  50  causes clutch coil to be activated, thereby forcing clutch plates contact one another. When clutch coil has voltage applied, clutch plates are pulled together and pulleys begin to move simultaneously. Thus, weights being to move with lifting bar. 
         [0028]      FIG. 11A  illustrates a back view of weightlifting apparatus  10  in a disengaged position, such as prior to a lift or during a grip release.  FIG. 11B  is a detailed view of grip rail  38  in a released position. When grip rail is released, switch  50  contacts are opened. If one or both of switches  50  are released, both clutch assemblies  55  will be deactivated, as shown in  FIG. 11C . Deactivation of switches  50  causes clutch coil to be deactivated, thereby separating clutch plates and leaving a gap  90  therebetween. Therefore, pulleys  60   a  and  60   b  begin to move independently and weight support elements  33 , carrying weights  30  are disengaged from lifting bar  22  drop to a released position as shown in  FIG. 11A . 
         [0029]    Various changes and modifications may be apparent to those skilled in the art. It is the intent that these changes and modifications are to be encompassed within the spirit of the appended claims and that the invention described herein and shown in the accompanying drawings is illustrative only and not intended to limit the scope of the invention.