Abstract:
A key operated switch that provides enhanced operational characteristics wherein the rotary motion of a key is translated into the actuation of a switch mechanism that rapidly establishes an electrical connection between a source of electrical current and a load. The switch uses a toggle adapted to interact with a standard switching mechanism which reduces the number of components and the cost of the switch. The key cylinder is coupled to a yieldable member such as spring to provide a positive or snap action when the key cylinder is rotated with a prescribed arc of rotation which reduces the complexity of the switch.

Description:
[0001]     This application claims the benefit of the filing date of a provisional application having Ser. No. 60/658,081 which was filed on Mar. 3, 2005. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to the field of electrical switches. More specifically, this invention relates to a key operated security switch.  
         [0004]     2. Description of the Related Art  
         [0005]     Key operated switches are common in the art and are used to provide a means to conveniently and affirmatively switch electrical current. Key operated switches provide added security by permitting only those individuals with a key to operate the switch. Many variations of key operated switches exist that utilize a key which acts upon a mechanism to connect a load or device to an electrical current. A typical example is a key operated switch that requires that a key be inserted into a lock mechanism and rotated at least 90 degrees in a particular direction in order to switch power on. To switch the power to a load off, the actuation process is reversed. Switches of this type can be quite complicated and often require many specialized and expensive parts to convert the action of turning a key in the switch into the actuation of the device itself. Moreover, switches of this type generally require that the key be rotated at least 90 degrees in a particular direction to actuate the device.  
         [0006]     The present invention seeks to improve on the prior art by providing a switch that provides a reduced number of moving parts, can be produced at reduced cost and provides improved operational characteristics.  
       SUMMARY OF THE INVENTION  
       [0007]     The present invention is a switch that provides enhanced operational characteristics wherein the rotary motion of a key is translated into the actuation of a switching mechanism that rapidly establishes an electrical connection between a source of electrical current and a load. The switch comprises an actuator coupled between a key cylinder and a toggle. When a key is placed in the key cylinder and rotated within an arc of rotation of approximately 60 degrees, the rotation of the key cylinder engages the actuator which converts the rotation of the key cylinder into a rotation of the toggle causing the toggle to trigger a switch mechanism. The switch uses a toggle adapted to interact with a standard switching mechanism which reduces the number of components and the cost of the switch. The key cylinder is coupled to a yieldable member such as spring to provide a positive or snap action when the key cylinder is rotated with the prescribed arc of rotation which thus reducing the complexity and improving the operational characteristics of the switch.  
         [0008]     The foregoing has outlined, rather broadly, the preferred feature of the present invention so that those skilled in the art may better understand the detailed description of the invention that follows. Additional features of the invention will be described hereinafter that form the subject of the claims of the invention. Those skilled in the art should appreciate that they can readily use the disclosed conception and specific embodiment as a basis for designing or modifying other structures for carrying out the same purposes of the present invention and that such other structures do not depart from the spirit and scope of the invention in its broadest form. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]     Other aspects, features and advantages of the present invention will become more fully apparent from the following detailed description, the appended claim, and the accompanying drawing in which similar elements are given similar reference numerals wherein:  
         [0010]      FIG. 1  is a perspective view of an assembled switch according to the present invention;  
         [0011]      FIG. 2  is an exploded view of the switch of  FIG. 1 ;  
         [0012]      FIG. 3A  is a side view of the toggle of  FIG. 2 ;  
         [0013]      FIG. 3B  is a top view of the toggle of  FIG. 3A ;  
         [0014]      FIG. 3C  is a bottom view of the toggle of  FIG. 3A ;  
         [0015]      FIG. 3D  is a front view of the toggle of  FIG. 3A ;  
         [0016]      FIG. 4A  is a top view of the switch in the first position;  
         [0017]      FIG. 4B  is a cutaway side view of the switch in the first position;  
         [0018]      FIG. 5A  is a top view of the switch in the second position; and  
         [0019]      FIG. 5B  is a cutaway side view of the switch in the second position. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0020]      FIG. 1  shows a key operated switch  10  according to an embodiment of the present invention. The switch includes a key cylinder  12  which is capable of being rotated between a first position P 1  and a second potion P 2  spanning an arc of approximately sixty (60) degrees. The switch  10  includes a switching mechanism configured as a single pole double throw (SPDT) switch with an input terminal  14  for connection to a power source (not shown), a first output terminal  16  for connection to a first load (not shown) and a second output terminal  18  for connection to a second load (not shown). In operation, a key (not shown) is inserted into the key cylinder  12  and then rotated to the first position P 1  which makes a first conductive path between the input terminal  14  and the first output terminal  16  and, simultaneously, breaks a second conductive path between the input terminal  14  and the second output terminal  18 . The key can also be rotated to the second position P 2  which breaks the first conductive path and, simultaneously, makes the second conductive path.  
         [0021]      FIG. 2  shows an exploded view of the key operated switch  10  of  FIG. 1 . The actuator  34  is coupled between the key cylinder and the toggle  50 . When a key (not shown) is placed in the key cylinder  12  and rotated within the prescribed arc of rotation (see  FIG. 1 ), the rotation of the key cylinder  12  engages the actuator  34  which converts the rotation of the key cylinder into a rotation of the toggle causing the toggle to trigger a switch mechanism located within switch housing  70 . The toggle  50  is adapted to interact with the switch mechanism which is a standard switch mechanism thereby reducing the number of components and the cost of the switch. The key cylinder  12  is coupled to a yieldable member such as spring  32  to provide a positive or snap action when the key cylinder is rotated with the prescribed arc of rotation which increases the performance and reduces the complexity of the switch.  
         [0022]     The key cylinder  12  comprises a central body  17  having a top portion  19  with a key opening  11  for receiving a key (not shown) and a bottom portion  15  for coupling to the actuator  34 . The top portion  19  has a generally circular shape with a diameter dimensioned to allow the key cylinder  12  to sit over the central opening of the ground strap  20  without having it extend through the central opening. The central body  17  has a generally cylindrical shape with two flat portions  9  (one shown) on opposite sides dimensioned to extend through similarly shaped central openings of the ground strap  20  and the top cover  24 . The configuration of the central body  17  provides an indexed mounting mechanism to enable the key cylinder  12  to be mounted in a particular orientation.  
         [0023]     The bottom portion  15  of the key cylinder  12  is generally square shaped and dimensioned to fit within the square shaped opening of the top portion of the actuator  34 . A fastening assembly comprising a square shaped clamp  38  and screw  40  is used to secure the bottom portion  15  of the key cylinder  12  to the top portion of the actuator  34 . A threaded lock nut  27  is fastened to the central body  17  to secure the key cylinder  12  to the ground strap  20  and to the top cover  24 . The key cylinder  12  is operatively coupled to the actuator  34  such that the key cylinder rotates together with the actuator  34 . A top yieldable member shown as a spring  32  provides snap action mechanism when the key cylinder is rotated between the first and second positions P 1 , P 2  (see  FIG. 1 ). One end of the spring  32  is coupled to a tab  28  located on the inside wall of the top cover  24  and the other end of the spring  32  is coupled to a tab  36  located on a side wall of the actuator  34 . Spring inserts  30  are used at each end of the spring to provide a more secure connection.  
         [0024]     The switch housing  70  supports a switching mechanism capable of having an on position and an off position. When the key cylinder  12  is moved to the first position P 1  (see  FIG. 1 ), the switch is placed in on position which causes a first conductive path to be made between the input terminal  14  and the first output terminal  16  and a second conductive path to be broken between the input terminal  14  and the second output terminal  18 . When the key cylinder  12  is moved to the second position P 2  (see  FIG. 1 ), the reverse occurs, such that switch moves to the off position causing the first conductive path to be broken and the second conductive path to be made. Thus, the switching mechanism by making either the first or second conductive paths but not both conductive paths simultaneously. In other words, when the first conductive path is made, the second conductive path is broken and when the first conductive path is broken, the second conductive path is made.  
         [0025]     The input terminal  14  comprises a screw/clamp assembly for attaching to a conductor such as a wire conductor carrying a current from a power source of an electrical wiring system. The input terminal  14  also includes a first input conductor  72  and a second input conductor  82 . The first input conductor  72  is capable of forming the first conductive path by making electrical contact with a first output conductor  74  of the first output terminal  16  Likewise, the second input conductor  82  is capable of forming the second conductive path by making electrical contact with a second output conductor  84  of the second output terminal  18 . The first and second output terminals  16 ,  18  include a screw/clamp assembly for attaching to a conductor such as a wire conductor from a load of an electrical wiring system. The conductors  72 ,  74 ,  82  and  84  can be yieldable electrical conductors made from relatively thin metallic strips or other configurations. Electrical Contacts are provided at the free end of the conductors  72 ,  74 ,  82  and  84  to improve the electrical contact between the conductors.  
         [0026]     The toggle  50  is operatively coupled to the key cylinder  12  through the actuator  34 . The toggle is configured to respond to the rotation of the key cylinder and alternatively make and break the first and second conductive paths of the switching mechanism. The toggle  50  comprises a rod  43  made of plastic with opposite ends to pivot about holders  66  (one shown) located on opposite side walls of the housing  70  (see  FIGS. 3A through 3D  for further details of the toggle). The bottom portion of the toggle  50  supports a first actuating lobe  58  located to contact the first input conductor  72  and a second actuating lobe  60 , spaced apart from the first actuating lobe along the longitudinal axis of the rod, to contact the second output conductor  84 . The top portion of the toggle  50  supports an actuator pin  56  made of metal positioned to fit within the side walls  31 ,  33  of the bottom portion of the actuator  34 . A bottom yieldable member such as spring  64  has a top end coupled to a tab  62  on the bottom portion of the toggle  50  and a bottom end coupled to a tab  61  located on the inside base of the housing  70 . The spring  64  provides an upward bias to the toggle  50  to maintain the toggle in one of two positions (see  FIGS. 4B and 5B ). First and second stopper arms  52 ,  54  are located transversely to the longitudinal axis of the toggle and are located to contact stopper posts  51 ,  53  (see  FIG. 4B ) to prevent the toggle  50  from rotating or pivoting beyond a predetermined position. The stopper posts  51 ,  53  are made of rubber material to absorb the downward force of the stopper arms  52 ,  54 .  
         [0027]     The middle cover  42  comprises a housing with a pin opening  48  located and sized to allow the actuator pin  56  of the toggle  50  to extend through the opening to interact with the bottom portion of the actuator  34 . The middle cover  42  also includes a stopper arm opening  46  located and sized to allow the stopper arms  52 ,  54  to extend through the opening when the arms alternatively pivot upward and downward. The ground strap  20 , the top cover  24 , the middle cover  42  and the switch housing  70  are secured together to form the switch assembly by inserting screws (not shown) through openings  68  in the housing  70 , openings  44  in the middle cover  42 , openings  26  in the top cover  24  and openings  22  in the ground strap  20 .  
         [0028]     The ground strap  20  includes a ground terminal  25  for connection to a ground conductor (not shown) and ears  23  for attachment to an electrical junction box (not show). The ground strap  20  is made of conductive material such as galvanized steel or other conductive material. The top cover  24 , the middle cover  42  and the housing  70  are made of non-conductive material such as plastic or other non-conductive material. The top spring  32  and bottom spring  64  are yieldable or compressible members made of metallic material but other techniques and other materials such as plastic can be used.  
         [0029]      FIG. 4A  is top view of the switch  10  in a first position PI and  FIG. 4B  is a cutaway side view of the switch  10 . A explained below in detail, in the first position P 1 , the first conductive path is made and the second conductive path is broken (not shown). Referring to  FIG. 4A , it is assumed that the key cylinder  12  is rotated to the first position P 1  from the second position P 2 . In operation, a key  13  is inserted into the key cylinder  12  and rotated in a counterclockwise direction (arrow  90 ) along the longitudinal axis of the key cylinder with sufficient force to compress the spring. Further rotation causes the spring to uncompress and flex in the direction of arrow  98  which urges the key cylinder  12  to the first position P 1  thereby providing a positive or snap action movement. If an insufficient force is applied, then the bias of the spring  32  prevents the switch from moving to the first position P 1  thereby maintaining the switch in the second position P 2 .  
         [0030]     Referring to  FIG. 4B , the rotation of the key cylinder in the counterclockwise direction (arrow  90 ) causes the actuator  34  to rotate in the same direction. As the actuator  34  rotates in the counterclockwise rotation (arrow  90 ), the side walls of the actuator  34  contact the actuator pin  56  of the toggle  50  causing the toggle to rotate in a clockwise direction (arrow  93 ) along an axis perpendicular to the rotation of the key cylinder (arrow  90 ). This clockwise rotation (arrow  93 ) of the toggle must be of sufficient force to overcome the upward bias (arrow  94 ) of the bottom spring  64  which maintains the toggle in a particular position. Assuming that this clockwise rotation (arrow  93 ) is with sufficient force, then the clockwise rotation causes the first lobe  58  to move upward (arrow  94 ) away from the first input conductor  72  which allows the first input conductor  72  to move upward (arrow  94 ) because of the upward bias of the first input conductor. As the first conductor  72  moves upward, it will make electrical contact with the first output conductor  74  thereby making the first conductive path. Although not shown, simultaneous with the upward motion of the first lobe  58 , the second lobe  60  (see  FIG. 2 ) moves in the opposite direction (downward as shown by arrow  92 ) urging the second output conductor  84  downward thereby breaking the second conductive path between the second input conductor  82  and the second output conductor  84 . In addition, the rotation of the toggle  50  in the clockwise direction (arrow  93 ) causes the second arm  54  to move upward (arrow  94 ) and the first arm  52  to move downward (arrow  92 ) until it contacts stopper element  51  which prevents the toggle from further rotation. Moreover, the central portion of the spring  64  flexes towards the left direction (arrow  96 ) which maintains the toggle in the first position until an opposite force is applied to move the switch to the second position.  
         [0031]      FIG. 5A  is a top view of the switch in the second position P 2  and  FIG. 5B  is a cutaway side view of the switch in the second position P 2 . A explained below in detail, in the second position P 2 , the first conductive path is broken and the second conductive path is made (not shown). Referring to  FIG. 5A , it is assumed that the key cylinder  12  is rotated to the second position P 2  from the first position P 1 . In operation, the key  13  is inserted into the key cylinder  12  and rotated in a clockwise direction (arrow  91 ) along the longitudinal axis of the key cylinder with sufficient force to compress the spring. Further rotation causes the spring to uncompress and flex in the direction of arrow  97  which urges the key cylinder  12  to the second position P 2  thereby providing a positive or snap action movement. If an insufficient force is applied, then the bias of the spring  32  prevents the key cylinder  12  from moving to the second position P 2  thereby maintaining the switch in the first position P 1 .  
         [0032]     Referring to  FIG. 5B , the rotation of the key cylinder in the clockwise direction (arrow  91 ) causes the actuator  34  to rotate in the same direction. As the actuator  34  rotates in the clockwise rotation (arrow  91 ), the side walls of the actuator  34  contact the actuator pin  56  of the toggle  50  causing the toggle to rotate in a counterclockwise direction (arrow  99 ) along an axis perpendicular to the rotation of the key cylinder (arrow  91 ). This counterclockwise rotation (arrow  99 ) of the toggle must be of sufficient force to overcome the upward bias (arrow  94 ) of the bottom spring  64  which maintains the toggle in a particular position. Assuming that this counterclockwise rotation (arrow  99 ) is with sufficient force, then the counterclockwise rotation causes the first lobe  58  to move downward (arrow  92 ) urging the first input conductor  72  in the downward direction (arrow  92 ) toward the second output conductor  74  thereby making the first conductive path between the first input conductor  72  and the first output conductor  74 . Although not shown, simultaneous with the downward motion of the first lobe  58 , the second lobe  60  (see  FIG. 2 ) moves in the opposite direction (upward as shown by arrow  94 ) allowing the second output conductor  84  to move upward because of the upward bias of the second output conductor thereby making the second conductive path between the second input conductor  82  and the second output conductor  84 . In addition, the rotation of the toggle in the counterclockwise direction (arrow  99 ) causes the first arm  52  to move upward (arrow  94 ) and the second arm  54  to move downward (arrow  92 ) until it contacts stopper element  53  which prevents the toggle from further rotation. Moreover, the central portion of the spring  64  flexes towards the right direction (arrow  95 ) which maintains the toggle in the second position until an opposite force is applied to move the switch to the first position.  
         [0033]     It should be apparent to one skilled in the art that although the disclosure focuses on a SPDT switch, similar techniques can also be used with other electrical switches such as double pole switch, 3-way switch, 4-way switch and other devices, without departing from the spirit or the scope of the invention. For example, the switch of the present invention can be configured as an on/off switch such as a single pole single throw (SPST) switch with a single input terminal and single output terminal. In the SPST configuration, when the switch is in the first position P 1 , a conductive path is made between the input and output terminal thereby connecting power to a single load and, when in the second position P 2 , the conductive path is broken thereby disconnecting power from the load.  
         [0034]     While the invention has been described in detail and with reference to specific embodiments thereof, it will be apparent to those skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope thereof Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.