Abstract:
A switch assembly, an ON/OFF control mechanism for power supply, mainly comprises a switch knob, a contact control member, and a resilient contact piece, wherein the switch knob is to be depressed to drive a protuberance to directly oppress or release the contact control member so as to in turn oppress or release the resilient contact piece for effecting or cutting off a power supply. By using a simple structure like this, easy assembling, low cost, simplification of interactive process, and low breakdown ratio are made possible.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates generally to a switch assembly, and more particularly, to a switch assembly, which is implemented for ON/OFF control by taking advantage of a protuberance of a switch knob that directly depresses or releases a contact control member to thereby oppress or release a resilient contact piece to effect or cut off the power supply. 
     2. Description of the Prior Art 
     Power switch is a widely used electronic component for ON/OFF control of a power supply, and is highlighted in its structural complexity in consideration of cost, or furthermore, in its reliability of security. 
     For improvement of a switch assembly, many patents, such as U.S. Pat. Nos. 4,167,720, 4,937,548, 5,223,813, 5,451,729, 5,558,211, etc., have been disclosed, wherein a common defect is known as excessive elements being used down from a switch knob that results in a complicated interactive process with high breakdown ratio and fabrication cost. 
     For example, in the U.S. Pat. No. 5,223,813 shown in FIGS. 1, 2, 3, after a switch knob has been depressed, a link rod under the switch knob is driven to drive a sway component to oppress or release a resilient contact piece thereunder to enable an upper contact dot to depart from or contact with a lower contact dot to thereby effect or cut off a power supply. It can be operated all right under normal conditions, however, in consideration of cost, productivity, and blunt response, there are still rooms for further improvements. 
     SUMMARY OF THE INVENTION 
     The primary object of this invention is to provide a switch assembly for improvement of assembling work, production cost, response time, and breakdown ratio. 
     Another object of this invention is to pair a thermal-sensitive element with a tact control member so as to ensure security in case of overload or overheat. 
     For more detailed information regarding this invention together with further advantages or features thereof, at least an example of preferred embodiment will be elucidated below with reference to the annexed drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The related drawings in connection with the detailed description of this invention, which is to be made later, are described briefly as follows, in which: 
     FIG. 1 is an exploded view of a prior art in three dimensions; 
     FIG. 2 is a cutaway sectional view showing the prior art under OPEN (OFF) state; 
     FIG. 3 is a cutaway sectional view showing the prior art under CLOSE (ON) state; 
     FIG. 4 is an exploded view of an embodiment (1) of this invention in three dimensions; 
     FIG. 5 is an assembled cutaway sectional view showing the embodiment (1) of this invention under OPEN (OFF) state; 
     FIG. 6 is an assembled cutaway sectional view showing the embodiment (1) of this invention under CLOSE (ON) state; 
     FIG. 7 is an exploded view of another embodiment (2) of this invention in three dimensions; 
     FIG. 8 is a cutaway sectional view of the embodiment (2) showing another structure of a contact control member of this invention under CLOSE (ON) state; 
     FIG. 9 is a cutaway sectional view showing a cutoff action of the embodiment (2) of this invention in case of overload or overheat. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     A switch assembly of this invention illustrated in FIG. 4 mainly comprises a switch knob  1 , a casing  2 , a contact control member  3 , and a resilient contact piece  4 . 
     In the switch knob  1 , a dipped arcuate face is formed on a top end, also, an axle-supporting groove  11  is concavely and centrally disposed at a bottom end to enable the switch knob  1  to rotate surrounding the axle-supporting groove  11 , and the bottom end of the switch knob  1  is extended downwardly to form at least a protuberance  12 , which, in this case, is substantially a triangular protrusion. 
     The casing  2  is a hollow housing having an open lateral wall, wherein an opening  21  is formed at a top end of the casing  2 ; an axle-supporting rod  201  is protrusively resided on an inner wall under the opening  21  for assembling and disposing the switch knob  1  in the axle-supporting groove  11 ; a first and a second slot  23 ,  25  are arranged in a bottom end of the casing  2  for plugging a first and a second terminal  24 ,  26  respectively; a hollow combining column  202 , a stopper  22 , and a stationary supporting pin  27  are protrusively fitted on the inner wall, and a plurality of combining holes  203  are distributed to corners of the inner wall. Moreover, a cover  28  is provided to the casing  2 , wherein an assembling post  281  in a position corresponding to the hollow combining column  202  is protuberantly disposed on an inner wall of the cover  28 , and a plurality of combining holes  282  in positions corresponding to the combining holes  203  of the casing  2  are distributed to corners of the cover  28 ; and the cover  28  is riveted to joint with the casing  2  with a plurality of rivets  283 . 
     In the contact control member  3 , it is found: at least an upper lump  31  located on a top end of contact control member  3 ; the top end being extended to form a hook portion  32 ; at least a lower lump  33  formed at a bottom end of the contact control member  3  in a position substantially corresponding to the upper lump  31 ; and the contact control member  3  being extended to form a tail end  30  with a propping end  301 . Furthermore, an upright longitudinal slot  37  is trenched in a lateral face inside the contact control member  3  for assembling and jointing the contact control member  3  to the stationary supporting pin  27  of the casing  2  so that the contact control member  3  is movable up and down along the stationary supporting pin  27 . 
     The resilient piece  4  is provided with a contact hole  41  at its upper free end for combining with an upper contact dot  42  which is located right above a lower contact dot  241  of the first terminal  24 , and the lower end of the contact piece  4  is a flat sheet coupled with an upper end of the second terminal  26 , and is fixedly clamped between a fixing plate  251  and a sole plate of the casing  2 . 
     As shown in FIG. 5, an assembled cutaway sectional view of an embodiment (1) of this invention under OPEN (OFF) state controlled by a user, when the user depresses the right end of the switch knob  1 , the switch knob  1  is forced to rotate clockwise surrounding the axle-supporting rod  201  which is taken as a pivot. Simultaneously, taking the axle-supporting rod  201  as a pivot, the protuberance  12  rotates clockwise in an arcuate movement (leftward in this case), and the bottom end of the protuberance  12  slides from the right side of the upper lump  31  of the contact control member  3  to the left side of the upper lump  31  so that the resilient contact piece  4  is freed from constraint of the lower lump  33  of the contact control member  3  to bounce upwardly and allow the upper contact dot  42  to depart from the lower contact dot  241  so as to separate the first terminal  24  from the second terminal  26  and cut off the power supply accordingly. 
     As illustrated in FIG. 6, an assembled cutaway sectional view of the embodiment (1) of this invention under CLOSE (ON) state, when a user depresses the left end of the switch knob  1 , the switch knob  1  is forced to rotate counterclockwise and so is the protuberance  12  for arcuate movement (rightward in this case) by taking the axle-supporting rod  201  as a pivot. Simultaneously, the bottom end of the protuberance  12  slides from the left side of the upper lump  31  of the contact control member  3  to the right side to depress the contact control member  3  downwardly to have the lower lump  33  constrain the resilient contact piece  4  so that the upper contact dot  42  at the bottom face of the free end of the resilient contact piece  4  will contact the lower contact dot  241  to thereby build a ready route for the power supply to go through the first terminal  24 , the lower contact dot  241 , the upper contact dot  42 , the resilient contact piece  4 , and the second terminal  26 . 
     Moreover, under OPEN (OFF) state of the switch, the propping end  301  at the tail end  30  of the contact control member  3  is located exactly over the top face of the stopper  22  of the casing  2 , on the contrary, the propping end  301  will prop against the top face of the stopper  22  under CLOSE (ON) state and serve as a pivot center for rotation of the contact control member  3  so that the lower lump  33  will rotate counterclockwise to depress the resilient contact piece  4  and enable the upper contact dot  42  to contact the lower contact dot  241 . 
     Using such a simple structure, a power supply route can be effected or voided by depressing the switch knob  1  to have the protuberance  12  push or release the interacted contact control member  3  to in turn oppress or release the resilient contact piece  4 . 
     In another embodiment (2) of this invention illustrated in FIGS. 7,  8 , an assembling slot  34  is recessively disposed in a lateral face of the contact control member  3 , wherein a slot opening  341  is formed in a tail end of the assembling slot  34 ; a movable tail end  35  with the same function as the tail end  30  in embodiment (1) is assembled in the assembling slot  34 ; a flange  351  is formed enclosing a nearer end of the column body of the movable tail end  35 , the farther end of the movable tail end  35  is a propping end  352 , and the cross-sectional area of the movable tail end  35  is slightly smaller than that of the slot opening  341 ; and a resilient member  36  (a compressible spring in this case) is disposed in the assembling slot  34  so that the movable tail end  35  can be stretched or compressed relatively in the assembling slot  34  and limited by the flange  351 . 
     By taking advantage of assembling a paired metallic alloy strip  5  (thermal-sensitive element) to the movable tail end  35 , the alloy strip  5  will prop against the propping end  352  of the movable tail end  35  in case of overload or overheat (shown in FIG. 9) such that the movable tail end  35  will retreat back toward the casing of the contact control member  3 , and accordingly, the propping end  352  is interacted to depart from the top face of the stopper  22 . Thus, the lower lump  33  will rotate clockwise surrounding the stationary pillar  27  in the longitudinal slot  37  to have the resilient contact piece  4  set free from constraint and bounced upwardly to drive the upper contact dot  42  to escape from the lower contact dot  241  and thereby cut off the power supply to ensure security. 
     Although, this invention has been described in terms of preferred embodiments, it is apparent that numerous variations and modifications may be made without departing from the true spirit and scope thereof, as set forth in the following claims.