Patent Publication Number: US-10319544-B2

Title: Bolted pressure switch motor arrangement

Description:
TECHNICAL FIELD 
     This technology relates to an apparatus that shifts a bolted pressure switch assembly between OPEN and CLOSED conditions under the biasing forces of springs. 
     BACKGROUND 
     Electrical switches are often used to act as a main disconnect for commercial and industrial applications. The switch has to make and break the current at the contacts safely to ensure electrical connection and disconnection of the circuit. Since the switches are to make and break on load, an operating mechanism is incorporated before the contacts so as to first store the energy inside the mechanism by means of spring-linkage system, and to then let the mechanism release the stored energy to the contacts to make or break the current at some pre-determined velocities. Traditionally, an external handle is connected to the mechanism shaft and the energy to the mechanism is supplied manually by human effort. 
     SUMMARY 
     In embodiments described below, an apparatus includes an electrical switch assembly and a cam assembly. The switch assembly includes a first contact supported for movement into and out of electrical connection with a second contact. The cam assembly deflects a spring into a stressed condition. The cam assembly also moves the first contact into electrical connection with the second contact under a bias of the spring upon return deflection of the spring from the stressed condition. The apparatus further includes a motor having an output member. A linkage interconnects the output member with the cam assembly to deflect the spring into the stressed condition in response to movement of the output member. 
     In distinction from a manually operated handle, the motor can provide greater amounts of energy to be stored in the spring. Additionally, the motor can be actuated by wireless or other actuation means located remotely from the switch assembly for enhanced user safety. 
     In the given examples, the apparatus further includes a frame having an outer periphery configured for fitting within a switchboard cubicle. The motor and linkage are contained within the outer periphery of the frame to ensure a proper fit within the switchboard cubicle. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an electrical switch assembly and an apparatus that shifts the switch assembly between OPEN and CLOSED conditions under the biasing forces of springs. 
         FIG. 2  is a side view of the apparatus of  FIG. 1 . 
         FIG. 3  is an enlarged front view of the apparatus of  FIG. 1 , with certain parts omitted for clarity of illustration. 
         FIG. 4  is a view showing the parts of  FIG. 3  in different positions. 
         FIG. 5  is a view similar to  FIG. 4 , showing an alternative embodiment of the apparatus. 
         FIG. 6  also is a view similar to  FIG. 4 , showing another alternative embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     The apparatus illustrated in the drawings includes parts that are examples of the elements recited in the claims. The illustrated apparatus thus includes examples of how a person of ordinary skill in the art can make and use the claimed invention. These examples are described to meet the enablement and best mode requirements of the patent statute without imposing limitations that are not recited in the claims. 
     As shown in  FIG. 1 , an apparatus  10  includes an electrical switch assembly  12 . An actuator mechanism  18  is operatively interconnected with the switch assembly  12 . The actuator assembly  18  has a manually operable handle  20  for shifting the switch assembly  12  between OPEN and CLOSED conditions. A motor  24  and a linkage  28  also are provided for shifting the switch assembly  12  between the OPEN and CLOSED conditions. 
     The apparatus  10  is sized and shaped for installation in a switchboard (not shown) which, as known in the art, includes a cubicle for containing a switch assembly. The switch assembly  12  of  FIG. 1  is thus supported on a base panel  30  that is sized and shaped with reference to a switchboard cubicle. The motor  24  and the linkage  28  are supported on a frame  34  that projects from the base panel  30 . In the illustrated example, the motor  24  and the linkage  28  are supported on a front portion  36  of the frame  34 . The front portion  36  of the frame  34  has an outer periphery that is sized and shaped to fit closely within an inner periphery of the switchboard cubicle. 
     This particular example of a switch assembly  12  is known as a bolted pressure switch assembly. As shown in  FIG. 2 , the switch assembly  12  includes three sets  40  of electrical contacts. Each set  40  includes an upper stationary contact  42 , a movable contact  44 , and an intermediate stationary contact  46 . Lower stationary contacts  48  also are included. The movable contacts  44  are supported to pivot from open positions, as shown for example in  FIG. 2 , to closed positions in electrical contact with both the upper and intermediate stationary contacts  42  and  46 . This shifts the switch assembly  12  from the OPEN condition to the CLOSED condition. Fuses (not shown) would be installed to complete electrical current paths from the intermediate stationary contacts  46  to corresponding lower stationary contacts  48 . 
     The actuator mechanism  18  is operatively interconnected with the motor  24  and the linkage  28 , but is otherwise configured as known in the art. As shown partially in  FIG. 4 , the actuator assembly  18  thus includes an actuator shaft  50 , a cam assembly  52 , and a pair of springs  54 . The shaft  50  is supported for rotation about an axis  55 . The cam assembly  52  acts between the shaft  50  and the springs  54  to store and release energy in the springs  54 . 
     In operation, the shaft  50  is rotated from a first position to a second position. The shaft  50  can be rotated either manually by use of the handle  20  or automatically by use of the motor  24  and the linkage  28 . When the shaft  50  is rotating toward the second position, the cam assembly  52  first compresses one of the springs  54 , and then latches the compressed spring  54  in a stressed condition. The shaft  50  is next rotated back to the first position. When the shaft  50  is rotating back toward the first position, the compressed spring  54  remains latched, and the cam assembly  52  compresses the other spring  54  to a stressed condition. However, the cam assembly  52  does not latch the other spring  54  in the compressed condition. Instead, the cam assembly  52  releases the other spring  54  to snap back from the compressed condition. The return movement of the other spring  54  drives the cam assembly  52  to shift the switch assembly  12  from the OPEN condition to the CLOSED condition under the bias of the released spring  54 . The actuator mechanism  18  further includes a release button  58  ( FIG. 1 ) for releasing the latched spring  54 , which then drives the cam assembly  52  to shift the switch assembly  12  back to the OPEN condition in a known manner. 
     As best shown in  FIGS. 1 and 3 , the front portion  36  of the frame  34  has a rectangular outer periphery defined by upper and lower side sections  70  reaching longitudinally between transverse opposite end sections  72 . The actuator mechanism  18  is supported on the lower side section  70  of the frame  34 . The motor  24  is supported on the upper side section  70 . The linkage  28  extends from an end section  72  of the frame  34  to the actuator mechanism  18  on the lower side section  70 . Arranging and containing the motor  24  and the linkage  28  within the outer periphery of the frame  34  in this manner helps to ensure that the entire apparatus  10  will fit properly within the inner periphery of the switchboard cubicle. 
     The linkage  28  includes first, second and third links  80 ,  82  and  84 . The first link  80  is anchored to the end section  72  of the frame  34 , and is movable pivotally about an axis  85 . The second link  82  interconnects the first and third links  80  and  84  through couplings having respective pivotal axes  87  and  89 . The third link  84  interconnects the second link  82  with the rotatable shaft  50  at the cam assembly  52 . The pivotal axes  85 ,  87  and  89  in the linkage  28  are all parallel to the rotational axis  55  of the shaft  50 . 
     This example of a motor is a linear actuator having a fluid piston-cylinder  100  with an output shaft  102  that is driven to reciprocate along an axis  105 . A bracket  106  is fixed to the upper side section  70  of the frame  34 . The motor  24  is supported on the bracket  106  for pivotal movement about an axis  107  that also is parallel to the axis  55  at the rotatable shaft  50 . The output shaft  102  is coupled to the first link  80  for movement about another parallel pivotal axis  109 . 
     When the motor  24  is actuated to extend the output shaft  102  outward from the piston-cylinder  100 , the output shaft  102  moves the linkage  28  from the condition of  FIG. 3  toward the condition of  FIG. 4 . The third link  84  then rotates the shaft  50  such that the cam assembly  52  compresses and latches one of the springs  54 , as described above. When the output shaft  102  is next retracted toward the position of  FIG. 3 , the cam assembly  52  stresses and releases the other spring  54  to shift the switch assembly  12  into the CLOSED condition under the bias of the released spring  54 , also as described above. 
     The linkage  28  can be disconnected if the handle  20  is to be used instead of the motor  24 . This can be accomplished, for example, by disconnecting second link  82  from the third link  84 . However, in distinction from the handle  20 , the motor  24  can provide greater amounts of energy to be stored in the springs  54 . Additionally, the motor  24  can be actuated in the forgoing manner by the use of any suitable actuation means known in the art, including wireless or other actuation means that can be located remotely from the switch assembly  12  for enhanced user safety. 
     Another embodiment is shown partially in  FIG. 5 . In this embodiment, the motor  24  and linkage  28  extend in series from the frame  34  to the actuator mechanism  18 . The motor  24  is fixed to an end section  72  of the frame  34 . The linkage  28  includes first and second pivotally coupled links  120  and  122  reaching from the output shaft  102  to the actuator shaft  50 . The embodiment of  FIG. 6  is similar, but the linkage  28  includes an L-shaped link  130  reaching to the front side of the frame  34  to engage the actuator shaft  50  at that location. 
     This written description sets for the best mode of carrying out the invention, and describes the invention so as to enable a person of ordinary skill in the art to make and use the invention, by presenting examples of the elements recited in the claims. The detailed descriptions of those examples do not impose limitations that are not recited in the claims, either literally or under the doctrine of equivalents.