Abstract:
A braking mechanism operably engaging at least one wheel where the mechanism is capable of transitioning the at least one wheel between unlocked and locked states is provided. The braking mechanism includes a flipper and a cam. The flipper is adapted to move in X, Y and Z-directions and includes a discontinuous track having an open slot portion and a surface path portion. The open slot portion includes a home position and an engaged position. The cam includes a pin which cooperatively moves along the discontinuous track. When the at least one wheel is in an unlocked state, the pin is in the home position and when the at least one wheel is in a locked state, the pin is in the engaged position.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     Not applicable. 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable. 
     BACKGROUND OF THE INVENTION 
     The present invention relates to a brake activation mechanism, more particularly, to a brake activation mechanism for movable furniture, such as chairs, beds, tables and the like. Although the following discussion relates to movable chairs, the present invention extends to all pieces of movable furniture on wheels. 
     Wheels are used on movable furniture, such as chairs, to allow for easy movement of the chair even while a person is seated in it. It is often desired to lock the wheels to secure the movable furniture when it is not being moved by a user. For example, a chair is equipped with caster wheels to allow a healthcare professional or other caretaker to easily move furniture, but locked casters are desired when a person is getting in and out of the chair or when the chair and person are not attended by a healthcare professional or other caretaker. Accordingly, pieces of movable furniture with casters may also include a braking mechanism. Users of the movable chairs, beds, and tables require a fast and simple way to activate and deactivate these caster brakes. 
     For example in healthcare, caretakers have faced a number challenges when dealing with movable furniture. One of those challenges has been the need to bend down to activate and deactivate the braking mechanism, and not having a stable hold on the chair, bed, or table while doing so. This is inconvenient for both caretakers and patients alike. 
     Caretakers often are not able to activate and deactivate the braking mechanism on both sides of the piece of furniture. This is inconvenient for the caretakers, and can create difficulties when transferring patients in and out of a movable chair because the activation device may be between the chair and another piece of furniture or too close to a wall, and therefore not accessible. Furthermore, braking mechanisms having one lever to activate the caster brakes and another lever to deactivate the caster brakes are cumbersome and confusing to users, especially in emergency situations. 
     Thus, a brake activation mechanism that allows a user to maintain a hold on a piece of movable furniture during activation and to access an activation/deactivation pedal from both sides of the furniture is activated is desired. 
     BRIEF SUMMARY OF THE INVENTION 
     In one embodiment of the present invention, a braking mechanism operably engages at least one wheel and can transition the at least one wheel between unlocked and locked states. The braking mechanism includes a flipper and a cam. The flipper includes a discontinuous track having an open slot portion and a surface path portion. The open slot portion includes a home position and an engaged position. The cam includes a pin which cooperatively moves along the discontinuous track. In the unlocked state, the pin is located in the home position. As the at least one wheel transitions from the unlocked state to the locked state, the pin moves along the open slot portion from the home position to the engaged position. As the at least one wheel transitions from the locked state to the unlocked state, the pin moves along the open slot portion and then along the surface path portion from the engaged position to the home position. 
     In another embodiment of the present invention, a braking mechanism includes at least one pedal, a connecting rod, a flipper, a cam, a cable junction and cables. The at least one pedal is fixed to an end of the connecting rod. The flipper is movable in X, Y and Z-directions and includes a discontinuous track. The cam is attached to the connecting rod and includes a pin cooperatively movable within the discontinuous track. The cable junction is attached to the connecting rod. Each cable includes one end attached to the cable junction and a second end engaging a brake. 
     In yet another embodiment of the present invention, a supporting platform includes a chassis, a plurality of wheels attached to an underside of the chassis, and a mechanism operatively connected to the plurality of wheels. Each wheel includes a brake and the mechanism is capable of transitioning the wheels between locked and unlocked states. The mechanism includes a connecting rod, an activation subassembly and a cable junction attached to the connecting rod, and a pedal fixed to a connecting rod end. The activation subassembly includes a plate fixed to the chassis, a flipper having a discontinuous track, a spring biased rod pivotally connecting the plate and flipper, and a cam fixed to the connecting rod. The cam includes a pin which cooperatively travels within the discontinuous track. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing and other items and advantages of the present invention will be appreciated more fully from the following figures, where like reference characters designate like features in which: 
         FIG. 1  is a perspective view of the braking activation mechanism in one embodiment of the invention, the brake activation mechanism including a cable junction and an activation subassembly; 
         FIG. 2  is a perspective view of the braking activation mechanism of  FIG. 1  attached to a movable chassis; 
         FIG. 3  is a top perspective view of the cable junction of the braking activation mechanism of  FIG. 1 ; 
         FIG. 4  is a side view of the cable junction of  FIG. 3  when the braking activation mechanism is in an unlocked state; 
         FIG. 5  is a side view of the cable junction of  FIG. 3  when the braking activation mechanism is in a locked state; 
         FIG. 6  is a side perspective view of a portion of  FIG. 2 , showing a braked caster; 
         FIG. 7  is a side perspective view of the activation subassembly of the braking activation mechanism of  FIG. 1 , the activation subassembly including a pin and a discontinuous track; 
         FIG. 8  is a top view of the activation subassembly of  FIG. 7 ; 
         FIG. 9  is a schematic side view of the activation subassembly of  FIG. 7 , where the braking activation mechanism is in the unlocked stated and the pin is in a home position of the discontinuous track; 
         FIG. 10  is a schematic side view of the activation subassembly of  FIG. 7 , where the braking activation mechanism is being activated and the pin is in a first temporary stop position of the discontinuous track; 
         FIG. 11  is a schematic side view of the activation subassembly of  FIG. 7 , where the braking activation mechanism is in the locked state and the pin is in an engaged position of the discontinuous track; 
         FIG. 12  is a schematic side view of the activation subassembly of  FIG. 7 , where the braking activation mechanism is being activated and the pin is in a second temporary stop position of the discontinuous track; 
         FIG. 13  is a schematic side view of the activation subassembly of  FIG. 7 , where the braking activation mechanism is being activated and the pin is traveling along a surface path portion of the discontinuous track; 
         FIG. 13A  is a cutaway end view of the activation subassembly of  FIG. 13 ; 
         FIG. 14  is a schematic side view of the activation subassembly of  FIG. 7 , where the braking activation mechanism is in the unlocked stated and the pin is in the home position of the discontinuous track; and 
         FIG. 14A  is a cutaway end view of the activation subassembly of  FIG. 14 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     For purposes of description herein, it is to be understood that the specific devices illustrated in the attached drawings, and described below are simply exemplary embodiments of the invented concepts. Hence, specific dimensions and other physical characteristics relating to the embodiments disclosed herein are not to be considered as limiting. Also, components described hereinafter as making up various elements of the invention are intended to be illustrative and not limiting. Many suitable components that would perform the same or similar functions as the components described herein are intended to be considered within the scope of the invention. 
     Referring to  FIG. 1 , the present brake activation mechanism  10  includes a connecting rod  12  having a first end  14  and a second end  16 ; at least one pedal  18  attached to the connecting rod; a cable junction  20  and an activation sub assembly  22 . As illustrated in  FIG. 2 , the brake activation mechanism  10  can be attached to a chassis  24 . The chassis  24  can be attached to a supporting platform of a chair, a bed, a table, or any other movable product. 
     Referring to  FIGS. 1 and 2 , the connecting rod  12  may be any shape, but preferably includes at least one planar surface. In one embodiment, the connecting rod  12  is a tube having a square cross section. The connecting rod  12  is attached to a chassis  24  and spans a width of the chassis. In an exemplary embodiment, the connecting rod  12  is attached to an underside of the chassis  24 . At least one pedal  18  is fixed to an end of the connecting rod  12  and preferably, a pedal  18  is fixed to the first end  14  of the connecting rod  12  and a pedal is fixed to the second end  16  of the connecting rod. The pedal  18  extends slightly from underneath a side of the chassis  24 . The pedal may be any shape, but preferably has a flat paddle shape for easy foot access. In an exemplary embodiment, the cable junction  20  and actuation subassembly  22  are positioned toward opposite ends  14 ,  16  of the connecting rod  12 . However, the cable junction  20  and activation subassembly  22  can be positioned anywhere on the connecting rod  12 . 
     Now referring to FIGS.  1  and  3 - 6 , the cable junction  20  holds a plurality of brake cables  21  and includes a first cable holding portion  26  and a second cable holding portion  28 . The first cable holding portion  26  of the cable junction  20  includes slits  30  at a top edge and fastening apertures at a bottom end. First ends  31  of the plurality of brake cables  21  fit in the slits  30  and are held there. Fasteners  32 , such as bolts, pass through the fastening apertures at the bottom end of the first cable holding portion  26  to secure the first cable holding portion of the cable junction  20  to the connecting rod  12 . The second cable holding portion  28  of the cable junction  20  includes a V-shaped plate  34  and an adjacent attached L-shaped bracket  36 . The V-shaped plate  34  is attached to the chassis  24  by fasteners  38 , such as bolts, and is apertured to contain a bearing  40  that surrounds the connecting rod  12  at a first bearing point. The L-shaped bracket  36  contains notches  42  for supporting brake cable end fittings  44  through which the plurality of brake cables  21  pass. A spring  46  having a first end  48  and a second end  50  is connected at its first end  48  to the first cable holding portion  26  and at its second end  50  to the second cable holding portion  28 . As illustrated in  FIG. 6 , second ends  52  of the plurality of brake cables  21  are operatively attached to a plurality of brakes  54 . In a preferred embodiment, the brakes  54  are attached to wheels such as casters  56 . 
     As illustrated in  FIGS. 7 and 8 , the activation subassembly  22  includes a plate  58 , a cam  60 , a flipper  64  having a discontinuous track  66  and ramp  68 . The plate  58  is fixed to the chassis  24  by fasteners  70 , such as bolts, and apertured to contain a bearing  72  that surrounds the connecting rod  12  at a second bearing point. The plate  58  further includes a guide rod  74 , a spring connection rod  76 , and a spring  77  biased rod  78 . The guide rod  74  protrudes from a center of the plate  58  towards the center of the brake activation mechanism  10 . The spring connection rod  76  protrudes from an upper portion of the plate  58  away from the center of the mechanism  10 . The spring  77  biased rod  78  protrudes from the plate  58  toward the center of the mechanism  10 . 
     Referring to  FIG. 7 , the cam  60  includes a tab  80  at its lower end, a pin  82  at its upper end, and a guide track  84  proximate its center. The tab  80  is apertured to allow fasteners  86 , such as bolts, to pass there through and fix the cam  60  to the connecting rod  12 . The pin  82  protrudes from the cam  60  towards the center of the mechanism  10 . The pin  82  travels along a path defined by the discontinuous track  66  of the flipper  64 . The guide track  84  houses the guide rod  74  that is fixed to the plate  58 . The guide rod  74  moves in the guide track  84  to maintain the position of the cam  60  relative to the plate  58 . 
     Still referring to  FIG. 7 , the flipper  64  includes an upper portion  88  and a lower portion  90 . The lower portion  90  of the flipper  64  is positioned at the upper end of the cam  60  on the side of the cam that is closest to the center of the mechanism  10 . The lower portion  90  includes the discontinuous track  66 , the ramp  68 , and an aperture. The spring  77  biased rod  78  protruding from the plate  58  passes through the aperture to loosely and pivotably connect the flipper  64  to the plate. The discontinuous track  66  is a complete and closed loop including two types of track, namely an open slot portion  92  and a surface path portion  94 . The open slot portion  92  of the discontinuous track  66  includes a home position  96  and bends which define a first temporary stop position  98 , an engaged position  100  and a second temporary stop position  102 . The home position  96 , first temporary stop position  98 , engaged position  100  and secondary temporary stop position  102  function as stop points for the pin  82 . The home position  96  is located at one end of the open slot portion  92  of the discontinuous track  66  and the ramp  68  is located at an opposite end of the open slot portion. The ramp  68  operates to transition the pin  82  from the open slot portion  92  to the surface path portion  94  of the discontinuous track  66 . The surface path portion  94  is defined by a route connecting the ramp  68  and home position  96  in the open slot portion  92 . The surface path portion  94  is located on a planar surface of the lower portion  90  of the flipper  64  which faces the plate  58 . The upper portion  88  of the flipper  64  is positioned over the cam  60  and the plate  58 , away from the center of the mechanism  10 . As best illustrated in  FIG. 8 , a spring  104  connects the plate  58  spring connection rod  76  to the flipper  64  upper portion  88 . In particular, a first end  106  of spring  104  engages the spring connection rod  76  and a second end  108  engages the upper portion  88 . 
     When the brake activation mechanism  10  is deactivated, the chassis  24  is movable and the at least one pedal  18  is parallel with the floor. The first and second cable holding parts  26 ,  28  of the cable junction  20  are perpendicular to the floor and parallel to each other as illustrated in  FIG. 4 . Referring to  FIG. 9 , the pin  82  is in the home position  92  in the discontinuous track  66  of the flipper  64 . 
     To activate the brake activation mechanism  10 , a user depresses a pedal  18 . The pedal  18  rotates downward relative to the connecting rod  12  forming an acute angle with the floor. Where there is a pedal  18  located on opposite sides of the chassis, the user only needs to push one of the pedals which causes both pedals to rotate downward. For clarity, activation and deactivation of the brake activation mechanism are described in terms of one pedal, but it is to be understood that the mechanism may include two pedals. Because the pedal  18  is fixed to the connecting rod  12 , the connecting rod also rotates. As the connecting rod  12  rotates, the cam  60  which is fixed to the connecting rod, also rotates. As illustrated in  FIGS. 9-14 , rotation of the cam  60  causes the pin  82  to move along the discontinuous track  66  of the flipper  64 . First, the user steps on the pedal  18 , which moves the pin  82  from the home position  96  ( FIG. 9 ) to a first temporary stop position  98  ( FIG. 10 ) in the open slot portion  92  of the discontinuous track  66 , thereby stretching the spring  104  between the flipper  64  and the plate  58 . The stretch of the spring  104  and movement of the spring over the plate  58  provides audible feedback to the user to signal that the brake activation mechanism  10  will engage. Concomitantly, the first cable holding portion  26  of the cable junction  20 , which is fixed to the connecting rod  12 , also rotates with the pedal  18  and connecting rod. The first cable holding portion  26  rotates away from the second cable holding portion  28  of the cable junction  20 , thereby creating an obtuse angle between the lower ends of the first and second cable holding portions. When the user then removes his or her foot from the pedal  18 , the pedal slightly rotates back up away from the floor, but still maintains a rotated position relative to the floor. As the pedal  18  rotates slightly back, the connecting rod  12  also rotates slightly, which causes the pin  82  on the cam  60  to snap up from the first temporary stop position  98  ( FIG. 10 ) to the engaged position  100  ( FIG. 11 ). The first cable holding portion  26  of the cable junction  20  remains angled away from the second cable holding portion  28 , thereby forming an obtuse angle between the lower ends of the first and second cable holding portions and holding tension in the plurality of braking cables  21 . Tension in the plurality of braking cables  21  causes the brakes  54  to be activated and lock the caster wheels  56 . The rotated position of the at least one pedal  18  is a visible indication to the user that the brakes  54  are engaged and the caster wheels  56  are locked. In one embodiment, three caster wheels  56  are equipped with brakes  54  to prevent any movement of the chassis  24  when the brakes are engaged. 
     To deactivate the brake activation mechanism  10 , the user again steps downward on pedal  18 . This downward motion rotates the cam  60  with the connecting rod  12  causing the pin  82  to move out of the engaged position  100  ( FIG. 11 ) in the open slot portion  92  of the discontinuous track  66  and to a second temporary stop position  102  ( FIG. 12 ). Movement of the pin  82  on the cam  60  to the second temporary stop position  102  stretches the spring  104  between the flipper  64  and the plate  58 , which again provides audible feedback to the user to signal the deactivation of the brake activation mechanism  10 . When the user removes their foot from the pedal  18 , the pedal  18  rotates up away from the floor which causes the connecting rod  12  to rotate, thereby rotating the cam  60 . The rotating cam  60  moves the pin  82  through the open slot portion  92  of the discontinuous track  66  toward the ramp  68 . Referring to  FIG. 13A , when the pin  82  contacts the ramp  68 , the ramp forces the flipper  64  to translate on the spring  77  biased rod  78  away from the pin  82 , cam  60 , and plate  58 . The pin  82  travels up the ramp  68 , behind the flipper and onto the surface path portion  94  of the discontinuous track  66  ( FIG. 13 ), and returns to the home position  96  ( FIG. 14 ). As soon as the pin  82  reaches the home position  96 , the spring  77  between the flipper  64  and the plate  58  forces the flipper back into alignment with the pin in its home position ( FIGS. 14 and 14A ). The first cable holding portion  26  of the cable junction  20  also returns to its deactivated position of being perpendicular to the floor releasing tension in the plurality of braking cables  21 . Release of the tension in the plurality of braking cables  21  causes the brakes  54  to be deactivated and unlock the caster wheels  56 . The unrotated position of the at least one pedal  18  is a visible indication to the user that the brakes  54  are disengaged and the caster wheels  56  are unlocked. 
     As described in detail above, the flipper  64  is adapted to include three degrees of motion which facilitates movement of the pin  82  along the discontinuous track  66 . As illustrated in  FIGS. 9-12 , the flipper  64  moves in an X-Y direction parallel to plate  58  as the pin  82  travels along the open slot portion  92  of the discontinuous track  66 . As illustrated in  FIGS. 13 and 13A , when the pin  82  contacts the ramp  68  and travels along the surface path portion  94  of the discontinuous track  66 , the flipper  64  additionally translates in a Z-direction away from plate  58 . Movement in the Z-direction is limited by upper portion  88  of the flipper  64  coming into contact with plate  58 . Referring to  FIGS. 14 and 14A , when the pin  82  reaches home position  96 , the flipper  64  again translates in a Z-direction toward the plate  58 .