Abstract:
A lifting mechanism having a first frame and a second frame. The second frame is movable relative to the first frame. A pulley is rotatably attached to one of the frames and a means for rotating the pulley is provided. A cordage is attached at one end to the pulley and another end of the cordage is attached to one of the frames. As the pulley is rotated the second frame is moved relative to the first frame.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    Lifting mechanisms for televisions and beds are generally complex and have many moving parts. Prior art lifts for such items often involve long extruded tracks and elaborate frames that must be attached to walls. Long extruded tracks and complicated mechanisms are expensive not only because of the extra material in the mechanism itself, but also due to additional labor required to install elaborate components onto the walls of a room where the lifting mechanism is to be used. Thus, there remains a need for an improved lift mechanism, which does not require an elaborate framework and that has a minimum number of moving parts. 
       SUMMARY OF THE INVENTION 
       [0002]    The present invention is a lifting mechanism for lifting objects such as a bed or a monitor. In an embodiment suited for lifting a monitor, a rod is rotatably held in a first frame. The first frame is affixed to a substantially vertical structure such as a wall. The first frame may be an extruded track. A second frame has a sliding portion, an arm and a mounting bracket. The sliding portion has rollers that are slidingly retained within the extruded track and allow the entire second frame to move vertically. A strap is affixed to the rod at one end and another end of the strap is attached to the second frame. The rod acts as a pulley and winds the strap around the rod when turned by a motor connected to the rod. As the motor turns the rod to wind the strap onto the rod the second frame and the monitor are lifted. The motor may be turned in an opposite direction to lower the television by unwinding the strap from the rod. A remotely located switch is used to connect current to the motor. The switch may connect current to the motor so that it turns the rod in a direction to wind the strap onto the rod. The switch may also connect current to the motor so that it turns the rod in a direction not unwind the strap from the rod. When the switch is switched to raise the monitor the motor will turn the rod to wind the strap onto the rod until the second frame contacts an upper switch which disconnects current from the motor to prevent it from moving the second frame above the upper switch. Similarly, when the switch is switched to lower the monitor the motor will turn the rod to unwind the strap the until the second frame contacts a lower switch which disconnects current from the motor to prevent it from moving the second frame below the lower switch. 
         [0003]    Another embodiment of the invention is suited to lift a bed or other objects supported on the horizontal structure. A first frame is made of the walls and ceiling of a room. A second frame is slidingly retained within the first frame and may move vertically. The second frame has rollers which roll against the walls to provide lateral stability. A motor is attached to the underside of the second frame and is connected to a shaft rotatably retained by bushings on the second frame. The shaft has a set of outer pulleys at the ends of the shaft and a set of inner pulleys that are next to the outer pulleys. Outer straps are received by the outer pulleys and inner straps are received by the inner pulleys. The motor turns the shaft to wind or unwind the straps on the pulleys to evenly raise or lower the second frame and bed. Similar switches may be employed in this embodiment to stop the motor from moving the second frame past its fully raised or lowered position. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0004]      FIG. 1  is a perspective view of a first embodiment of the lift of this invention shown with a flat panel monitor, with the lift retracted behind a cabinet; 
           [0005]      FIG. 2  is a an exploded perspective view of the lift shown in  FIG. 1 ; 
           [0006]      FIG. 3  is a side view of the lift shown in  FIG. 1 , with the lift in the raised position; 
           [0007]      FIG. 4  is a side view of the lift shown in  FIG. 1 , with the lift in the down position; 
           [0008]      FIG. 5  is a view of the lift shown in  FIG. 1 , with the lift in the raised position; 
           [0009]      FIG. 6  is a perspective view of a second embodiment of the invention shown supporting a bed in its first configuration; 
           [0010]      FIG. 7  is a perspective view showing the components of the lift shown in  FIG. 6 ; 
           [0011]      FIG. 8  is a perspective view of the lift shown in  FIG. 6  installed in a vehicle; 
           [0012]      FIG. 9  is a side view of the lift shown in  FIG. 6  installed in a vehicle with the lift in a partially lowered position; 
           [0013]      FIG. 10  is a side view of the lift shown in  FIG. 6  installed in a vehicle with the lift in a fully raised position; and 
           [0014]      FIG. 11  is a perspective view of a second embodiment of the invention shown supporting a bed in its second configuration. 
       
    
    
     DETAILED DESCRIPTION OF INVENTION 
       [0015]    The lifting mechanism of this invention  10  in one embodiment has a first frame that is an extruded track  12  mounted to a wall or other vertical surface. An exploded view of this embodiment is shown in  FIG. 2 . A motor  14 , which is operated by switch in a remote location, is mounted at the top of the extruded track  12  and turns a rod  16  that acts as a pulley and winds a strap  18  around the rod  16 . The strap  18  may be any cordage that is flexible enough to be wound around a pulley or rod. A first end of the strap  18  which is wrapped around the rod  16  is firmly attached to the rod  16  so that no slippage occurs. The switch is operatively connected to the motor  14  so that it may be switched to connect current to the motor  14  to rotate the rod  16  counterclockwise as viewed from the left. Since the strap  18  is wound over the top of the rod  16  counterclockwise rotation of the rod  16  will cause the strap  18  to be wound upon the rod  16 .  FIG. 2  best shows how the strap  18  is wound upon the rod  16 . The switch may also connect current to the motor  14  to rotate the rod  16  clockwise as viewed from the left side. This will cause the strap  18  to be unwound from the rod  16 . The rod  16  is supported at one end by a bushing  22  and is turned by the motor  14  at the other end through a gear box  24 . A second frame  28  has an arm  30 , a mounting bracket  32 , a sliding portion  34  and a pin  40 . The arm  30  is connected to the sliding portion  34 , which slides in the extruded track  12 . Rollers  36  are mounted on both sides of the sliding portion  34  and are slidingly retained within the extruded track  12 . The sliding portion  34  is bolted to the arm  30 . The mounting bracket  32  is permanently attached to the arm  30  and has four holes  36  that are in a standard pattern, which is common to most flat panel monitors and televisions. 
         [0016]    The strap  18  has a loop  39  at its second end that wraps around the pin  40  to attach the strap  18  to the second frame  28  and hold the second frame  28  in its vertical position. When the arm  30  is in its fully raised, first position, as shown in  FIGS. 1 ,  3 , and  5 , most of the length of the strap  18  is wound around the rod  16 . The pin  40  protrudes through the arm  30  and is placed so that it may contact an upper switch  42  or a lower switch  44  depending on the position of the arm  30 . When the arm  30  is in its fully raised position the pin  40  contacts the upper switch  42  to break the flow of current to the motor  14  required to turn the rod  16  counterclockwise. This prevents the arm  30  from being lifted above the point where the pin  40  contacts the upper switch  42  and also prevents the sliding portion  34  from jamming against the strap  14  as it is wound around the rod  16 . When the arm  30  is in its fully lowered, second position, as shown in  FIG. 4 , most of the length of the strap  18  is unwound from the rod  16 . In this position, the pin  40  contacts a lower switch  44  to break the flow of current to the motor  14  required to turn the rod  16  clockwise. This prevents the arm  30  from being lowered beyond the point where the pin  40  contacts the lower switch  44 . A safety pin  46  is placed near the end of the extruded track  12  to prevent the sliding portion  34  from leaving the track  12  in the event that either the lower switch  44  or strap  18  has failed. 
         [0017]    The lifting mechanism  10  of this embodiment is suited for raising or lowering a flat panel monitor  50 . A flat panel monitor  50  is mounted onto the mounting bracket  32  by placing screws in the four holes  36  of the mounting bracket  32 , which will align with holes in a flat panel monitor  50 . As shown in  FIG. 1  the lifting mechanism  10  may be placed behind a cabinet  52  to hide the monitor  50  when it is not in use.  FIG. 1  shows the fully raised, first position, which is also shown in  FIG. 3 . When a user wishes to use the monitor  50  he may then switch the switch to lower the monitor  50  and the motor  14  will turn the rod  16  clockwise to unwind the strap  18  from the rod  16 . When the monitor  50  reaches its fully lowered, second position, as shown in  FIG. 4  the pin  40  will contact the lower switch  44 , which will place the monitor  50  in a viewing position, yet allow the lifting mechanism  10  to remain hidden behind the cabinet  52 . When the user wishes to hide the monitor  50 , the switch may be reversed to raise the monitor  50  and the motor  14  will stop raising the monitor  50  when the pin  40  contacts the upper switch  42 . 
         [0018]    Another embodiment of the lifting mechanism  60  is shown in  FIGS. 6-11 . An exploded view of this embodiment in a first configuration is shown in  FIG. 7  and a second configuration is shown in  FIG. 11 . In this embodiment the first frame  61  is made of walls  62  and a ceiling  65  of a room. A second frame  64  is slidingly retained within the first frame  61 . The second frame  64  includes rollers  59  which roll along the walls  62  to provide lateral guidance for the second frame  64 . Extruded tracks may also be placed along the walls  62 , to provide further guidance for the rollers  59 , but are not necessary. A motor  63 , which is operated by a switch in a remote location, is connected to the second frame  64  from below and drives a shaft  66 . The shaft is rotatably held by bushings  67  to the second frame  64 . The shaft  66  has outer pulleys  72  which are at the ends of the shaft  66  and inner pulleys  68  that are next to the outer pulleys  72 . The switch is operatively connected to the motor  63  so current may be connected to the motor  63  so that it will rotate the shaft  66  and pulleys  68 ,  72  clockwise as viewed from the left end of the shaft  66 . The switch may also connect current to the motor  63  so that it rotate the shaft  66  and pulleys  68 ,  72  counterclockwise as viewed from the left end of the shaft. The inner pulleys  68  receive inner straps  70 , and the outer pulleys  72  receive outer straps  74 . Ends of each strap  70 ,  74  are attached to the pulleys  68 ,  72  so that no slippage occurs. The other ends of the straps  70 ,  74  are attached to the ceiling  65 . The straps  70 ,  74  wrap around the pulleys  68 ,  72  and hold the second frame  64  in its vertical position. The inner straps  70  are wound around the inner pulleys  68  from the bottom and the outer straps  74  are wound around the outer pulleys  74  from the top. The inner and outer pulleys  68 ,  72  are the same diameter. This configuration, which can be seen most clearly in  FIG. 7 , will wind or unwind all of the straps  70 ,  74  the same amount for each revolution of the shaft  66 . As the straps  70 ,  74  are wound or unwound from the pulleys  68 ,  72  the second frame  64  will move relative to the straps  70 ,  74  and rollers  75  prevent the straps  70 ,  74  from rubbing on the second frame  64 . 
         [0019]    This embodiment may also have the motor  63  mounted to the ceiling  65 , which is a part of the first frame  61 .  FIG. 11  shows the second configuration with the motor  63  mounted to the ceiling  65 . In this configuration the bushings  67  holding the shaft  66  are mounted to the ceiling  65 . The inner and outer straps  70 ,  74  are wound around the pulleys  68 ,  72  in a similar fashion to the previously mentioned configuration. Another set of pulleys  84  are mounted to the ceiling  65  with bushings  86  that rotatably hold a shaft  88 . The pulleys  84  provide guidance to the outer straps  74 . As the straps  70 ,  74  are wound or unwound from the pulleys  68 ,  72  the straps  70 ,  74  will pull the second frame up or down. 
         [0020]    This embodiment of the lift mechanism  60  is suited for lifting a bed  82  which is placed on the second frame  64 . When a user wishes to lower the bed from its stored, first position he will switch the switch so that the motor  63  rotates the shaft  66  and pulleys  68 ,  72 . In the first configuration the shaft  66  and pulleys  68 ,  72  rotate counterclockwise as viewed from the left end of the shaft  66  to lower the bed  82 . In the second configuration the shaft  66  and pulleys  68 ,  72  rotate clockwise as viewed from the left end of the shaft  66  to lower the bed. Since all of the pulleys  68 ,  72  are the same diameter, the straps  70 ,  74  are unwound from the pulleys  68 ,  72  evenly. This provides even movement of the bed  82  downward. When the bed  82  is fully lowered in its second position the user will switch the switch so that it disconnects the current from the motor  63 . Alternatively, the second frame  64  can be set to contact a switch mounted on a wall  62  that will disconnect the current to the motor  63  when the bed  82  is fully lowered. When the user wishes to raise the bed to the stored position, the user will switch the switch so that the motor  63  rotates the shaft  66  and pulleys  68 ,  72  in the opposite direction necessary to lower the bed  82 . In the first configuration the shaft  66  rotates clockwise as viewed from the left end to raise the bed  82 , and in the second configuration the shaft  66  rotates counterclockwise as viewed from the left end to raise the bed  82 . Once the second frame  64  is fully raised the user will switch the switch to stop the motor  63 , or a switch may be placed on a wall  62  that the second frame  64  will contact to disconnect the current from the motor  63  and stop further upward movement. 
         [0021]    The above described invention is not to be limited to the details given but may be modified within the scope of the following claims.