Abstract:
A jerking-initiated switch includes first and third shank members secured to an insulating frame and spaced apart from each other, and at least one second shank member interposed therebetween. Each of the shank members has a contact terminal extending outwardly of the frame to electrically contact a substrate. Two limb members are integrally formed and are connected to the second shank member, and extend towards the first and third shank members, respectively, so as to form guideways that an electrically conductive ball is rollable thereon. Each guideway has idle and threshold regions at different heights such that the ball is caused to displace from one of the idle and threshold regions to the other of the idle and threshold regions in response to a jerking action, thereby placing the switch in one of the first and second switching states.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   This invention relates to a jerking-initiated switch, more particularly to a jerking-initiated switch having an electrically conductive ball rollable within an insulating frame to engage or disengage from two spaced apart electric contact terminals. 
   2. Description of the Related Art 
   Referring to  FIGS. 1 and 2 , a conventional jerking-initiated switch  100  is shown to include an insulating housing  101 , an electrically conductive ball  102 , four contact terminals  103 , and a plug  104 . In assembly, the ball  102  is received in the housing  101 , and an access opening of the housing  101  is closed by the plug  104 . Tapered contact ends  1031  of the contact terminals  103  are inserted into the housing  101  through four through holes  1041  in the plug  104  by using a tool (not shown). By contacting the ball  102  with the contact ends  1031  of two of the terminals  103 , the electric contact between the terminals  103  can be established. However, since the terminals  103  are mounted on the plug  104  and are disposed in a suspended state, the operation of the tool for assembling the terminals  103  must be precise so as to align the contact ends  1031  with one another. Moreover, as the terminals  103  are not firmly secured in the plug  104 , sensitivity of the switch  100  is unsteady. 
   The switch  100  can be mounted on a substrate  105  in an upright state shown in  FIG. 2 . The switch  100  can also be mounted under the substrate  105  by bending the terminals  103  such that an included angle (θ) is formed between the housing  101  and the substrate  105 . The angle (θ) is liable to be changed by an external force to result in failure of the switch  100 . 
   SUMMARY OF THE INVENTION 
   The object of the present invention is to provide a jerking-initiated switch which has contact terminals mounted in a steady manner, and which can achieve enhanced sensitivity. 
   According to this invention, the jerking-initiated switch includes an insulating frame which has a base wall and first and second upright walls extending respectively from first and second lateral sides of the base wall to define a rolling path. An electrically conductive ball is disposed to be rollable along the rolling path between first and second switching positions where the switch is in first and second switching states, respectively. An interconnecting member is disposed adjacent to the first lateral side, and extends to terminate at front and rear joining ends. Front and rear first shank members, which are made from an electrically conductive material, are respectively connected to the front and rear first joining ends, and extend to respectively terminate at front and rear first contact terminals that extend outwardly of the frame to electrically contact a substrate. At least one second shank member, which is made from an electrically conductive material, is secured to the base wall. The second shank member extends to terminate at a second contact terminal that extends outwardly of the frame to electrically contact the substrate, and at a second joint that is opposite to the second contact terminal. At least one limb member is integrally formed with and extends from the second joint to form a guideway along the rolling path such that the ball can slidably contact the limb member. The limb member extends towards the front and rear first shank members to terminate at a threshold region. The threshold region is spaced apart from the front and rear first shank members, and corresponds to the first switching position. The limb member has an idle region which is configured to correspond to the second switching position such that once the ball is caused to displace from one of the idle and threshold regions to the other of the idle and threshold regions in response to a jerking action, the switch is placed in one of the first and second switching states. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other features and advantages of the present invention will become apparent in the following detailed description of the preferred embodiments of the invention, with reference to the accompanying drawings, in which: 
       FIG. 1  is an exploded perspective view of a conventional jerking-initiated switch; 
       FIG. 2  is a sectional view of the conventional jerking-initiated switch mounted on a substrate; 
       FIG. 3  is a sectional view of the conventional jerking-initiated switch mounted under a substrate; 
       FIG. 4  is an exploded perspective view of the first preferred embodiment of a jerking-initiated switch according to this invention; 
       FIG. 5  is a schematic perspective view of the first preferred embodiment in a rest state; 
       FIG. 6  is a cross-sectional view of the first preferred embodiment in the rest state of  FIG. 5 ; 
       FIG. 7  is a view similar to  FIG. 5  but showing the first preferred embodiment in a jerked state; 
       FIG. 8  is a view similar to  FIG. 6  but showing the first preferred embodiment in the jerked state of  FIG. 7 ; 
       FIG. 9  is a view similar to  FIG. 5  but showing the first preferred embodiment in another rest state; 
       FIG. 10  is a view similar to  FIG. 6  but showing the first preferred embodiment in the rest state of  FIG. 9 ; 
       FIG. 11  is an exploded perspective view of the second preferred embodiment of a jerking-initiated switch according to this invention; 
       FIG. 12  is an exploded perspective view of the third preferred embodiment of a jerking-initiated switch according to this invention; 
       FIG. 13  is a schematic perspective view of the third preferred embodiment in a rest state; 
       FIG. 14  is a cross-sectional view of the third preferred embodiment in the rest state of  FIG. 13 ; 
       FIG. 15  is an exploded perspective view of the fourth preferred embodiment of a jerking-initiated switch according to this invention; 
       FIG. 16  is an exploded perspective view of the fifth preferred embodiment of a jerking-initiated switch according to this invention; 
       FIGS. 17 to 19  are respective schematic perspective views of the fifth preferred embodiment in different states; 
       FIG. 20  is an exploded perspective view of the sixth preferred embodiment of a jerking-initiated switch according to this invention; 
       FIG. 21  is an exploded perspective view of the seventh preferred embodiment of a jerking-initiated switch according to this invention; 
       FIG. 22  is a schematic perspective view of the seventh preferred embodiment in a rest state; 
       FIG. 23  is a cross-sectional view of the seventh preferred embodiment in the rest state of  FIG. 22 ; 
       FIG. 24  is an exploded perspective view of the eighth preferred embodiment of a jerking-initiated switch according to this invention; and 
       FIG. 25  is an exploded perspective view of the ninth preferred embodiment of a jerking-initiated switch according to this invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Before the present invention is described in greater detail, it should be noted that same reference numerals have been used to denote like elements throughout the specification. 
   Referring to  FIGS. 4 to 6 , the first preferred embodiment of a jerking-initiated switch according to the present invention is shown to comprise an insulating frame  1 , an electrically conductive ball  5 , and a first terminal unit  2 , a pair of second terminal units  4 , and a third terminal unit  3 . 
   The frame  1  includes a base wall  11  and a cover  6 . The base wall  11  has first and second lateral sides opposite to each other in a longitudinal direction (X), and front and rear sides opposite to each other in a first transverse direction (Y) transverse to the longitudinal direction (X). The base wall  11  has a pair of projecting blocks  12  disposed on the front and rear sides, and a pair of first through holes  13 , a pair of second through holes  14 , and a pair of third through holes  15  extending therethrough in a second transverse direction (Z) transverse to both the first transverse direction (Y) and the longitudinal direction (X) and disposed in the first lateral side, a middle region, and the second lateral side, respectively. The cover  6  has a base  61  and a surrounding wall  64  extending from a periphery of the base  61  to terminate at an opening  63  to receive the base wall  11 . The surrounding wall  64  includes first and second upright walls  641 , 642  extending in the second transverse direction (Z) to be connected to the first and second lateral sides, respectively. The cover  6  further has two projecting blocks  65  which are disposed to interengage the projecting blocks  12  so as to firmly secure the cover  6  to the base wall  11 , as shown in  FIG. 6 . Thus, an accommodation space  62  is confined between the base wall  11  and the cover  6 , and defines a rolling path therein. 
   The ball  5  is received in the accommodation space  62  to be rollable along the rolling path between first and second switching positions where the jerking-initiated switch is in first and second switching states, respectively (to be described in greater detail in the succeeding paragraphs). 
   The first and third terminal units  2 , 3  have the same construction and are made from an electrically conductive metal plate, such as a copper plate. Each of the first and third terminal units  2 , 3  includes a first (second) interconnecting member  20  ( 30 ), and front and rear first (third) shank members  21  ( 31 ). The first (second) interconnecting member  20  ( 30 ) extends in the first transverse direction (Y) to terminate at front and rear first (second) joining ends. The front and rear first (third) shank members  21  ( 31 ) are connected to the front and rear first (second) joining ends, respectively, and extend in the second transverse direction (Z) to terminate at front and rear first (third) contact terminals  23  ( 33 ), respectively. The front and rear first (third) contact terminals  23  ( 33 ) extend respectively through the first (three) through holes  13  ( 15 ) to be disposed outwardly of the base wall  11  so as to electrically contact a substrate  7 . Each of the first (third) shank members  21  has a shoulder portion  24  ( 34 ) that abuts against the base wall  11  when the respective contact terminal  23  ( 33 ) is extended through the respective through hole  13  ( 15 ) so as to secure the first (third) terminal unit  2  ( 3 ) to the frame  1 . 
   Each of the second terminal units  4  has a single-piece construction, and is made from an electrically conductive material, and includes a second shank member  42 , a first limb member  41 , and a second limb member  43 . The second shank member  42  extends in the second transverse direction (Z) to terminate at a second contact terminal  421  that extends through the respective second through hole  14  to be disposed outwardly of the base wall  11  so as to electrically contact the substrate  7 , and at a second joint  422  that is opposite to the second contact terminal  421 . The first and second limb members  41 , 43  have the same configuration, and extend from the second joint  422  in the longitudinal direction (X) and away from each other to form respectively first and second guideways  412 , 432  along the rolling path such that the ball  5  can slidably contact the first and second limb members  41 , 43 . The first and second limb members  41 , 43  extend respectively towards the first and third shank members  21 , 31  to terminate at first and second threshold regions  416 , 436 , respectively. The first and second threshold regions  416 , 436  are spaced apart from the first and third shank members  21 , 31 , respectively, and correspond to the first switching position. The first and second limb members  41 , 43  have first and second idle regions  415 , 435 , respectively, which are configured to correspond to the second switching position. 
   In this embodiment, each of the guideways  412 , 432  is configured to descend from the respective idle region  415 , 435  to the respective threshold region  416 , 436  in the longitudinal direction (X). Therefore, as shown in  FIGS. 5 and 6 , when the switch of this embodiment is mounted uprightly on an upper surface  71  of the substrate  7 , the ball  4  rests on one of the threshold regions  416 , 436  (the first threshold region  416  in  FIG. 5 ) to place the switch in the first switching state, where the second contact terminals  421  are electrically connected to one of the first and third contact terminals  23 , 33  (the first contact terminals  23  in  FIG. 5 ) through the ball  5 . 
   As shown in  FIGS. 7 and 8 , a jerking action will cause the switch to tilt and the ball  4  to displace from the threshold region  416  to the idle region  415  or  435  without contacting the first terminal unit  2  so as to place the switch in the second switching state, where the electric connection between the first and second contact terminals  23 , 421  is cut-off. 
   Thereafter, as shown in  FIGS. 9 and 10 , once the ball  4  rolls over the idle regions  415 , 435  and to the other one of the limb members  41 , 43  (the second limb member  43  in  FIG. 9 ) to rest in the corresponding threshold region  436 , the switch is placed in the first switching state, where the second contact terminals  421  are electrically connected to the other one of the first and third contact terminals  23 , 33  (the third contact terminals  23  in  FIG. 9 ) through the ball  5 . 
   As illustrated, in comparison with the conventional switch  100 , the first, second and third terminal units  2 , 4 , 3  in this invention are fitted into the frame  1  individually, and are retained therein by virtue of the engagement between the base wall  11  and the cover  6 . Thus, the problem associated with alignment of the terminals  103  in the housing  101  of the conventional switch  100  can be overcome, and the terminal units  2 , 4 , 3  can be retained on the frame  1  steadily and firmly. In addition, since the limb members  41 , 43  are of a plate shape, the area of contact between the limb members  41 , 43  and the ball  4  is increased to result in enhanced electric contact and improved sensitivity. 
   Referring to  FIG. 11 , the second preferred embodiment of a jerking-initiated switch according to this invention is shown to be similar to the first embodiment in construction. In the second embodiment, each of the first, second and third contact terminals  23 , 421 , 33  has a contact end  231 , 4211 , 331  which is bent to extend in the first transverse direction (Y) and which has a major surface that is adapted to be attached to the substrate  7  using a conventional SMT (surface mount technology) process. 
   Referring to  FIGS. 12 to 14 , the third preferred embodiment of a jerking-initiated switch according to this invention is shown to be similar to the first embodiment in construction. In the third embodiment, the switch is adapted to be mounted on a lower surface  72  of a substrate  70 . Specifically, the second joint  422  of each second shank member  42  has a bent connecting portion  423  which is bent to extend in the first transverse direction (Y) such that the respective first and second limb members  41 , 43  extend from the bent connecting portion  423  in the second transverse direction (Z). 
   Referring to  FIG. 15 , the fourth preferred embodiment of a jerking-initiated switch according to this invention is shown to be similar to the third embodiment in construction. In the fourth embodiment, each of the first, second and third contact terminals  23 , 421 , 33  has a contact end  231 , 4211 , 331  which is bent to extend in the first transverse direction (Y) and which has a major surface that is adapted to be attached to the substrate (not shown) using a conventional SMT process. 
   Referring to  FIGS. 16 to 19 , the fifth preferred embodiment of a jerking-initiated switch according to this invention is shown to be similar to the first embodiment in construction. In the fifth embodiment, each of the first and second guideways  412 , 432  is configured to ascend from the respective idle region  415 , 435  to the respective threshold regions  416 , 436  in the longitudinal direction (X) such that each pair of the first and second guideways  412 , 432  is V-shaped. Thus, the ball  5  is rested on the first or second idle region  415 , 435  to place the switch in the second switching state, as shown in  FIG. 17 , where the first and third contact terminals  23 , 33  are not electrically connected to the second contact terminals  421 . Once a jerking action causes the ball  5  to roll from the first or second idle region  415 , 435  to one of the first and second threshold regions  416 , 436  (the first threshold region  416  in  FIG. 18  or the second threshold region  436  in  FIG. 19 ), the switch is placed in the first switching state, where the first or third contact terminals  23 , 33  are electrically connected to the second contact terminals  421  through the ball  5 . 
   As illustrated, the switch of the present invention may be designed to be placed in a switch-on state (as shown in  FIG. 5 ) or a switch-off state (as shown in  FIG. 17 ) when mounted uprightly on a substrate. 
   Referring to  FIG. 20 , the sixth preferred embodiment of a jerking-initiated switch according to this invention is shown to be similar to the fifth embodiment in construction. In the sixth embodiment, each of the first, second and third contact terminals  23 , 421 , 33  has a contact end  231 , 4211 , 331  which is bent to extend in the first transverse direction (Y) and which has a major surface that is adapted to be attached to the substrate using a conventional SMT process. 
   Referring to  FIGS. 21 to 23 , the seventh preferred embodiment of a jerking-initiated switch according to this invention is shown to be similar to the third embodiment in construction. In the seventh embodiment, the first and second limb members  41 , 43  have a configuration the same as that of the fifth preferred embodiment, and is adapted to be mounted on a lower surface  72  of a substrate  70 . 
   Referring to  FIG. 24 , the eighth preferred embodiment of a jerking-initiated switch according to this invention is shown to be similar to the seventh embodiment in construction. In the eighth embodiment, each of the first, second and third contact terminals  23 , 421 , 33  has a contact end  231 , 4211 , 331  which is bent to extend in the first transverse direction (Y) and which has a major surface that is adapted to be attached to the substrate using a conventional SMT process. 
   Referring to  FIG. 25 , the ninth preferred embodiment of a jerking-initiated switch according to this invention is shown to be similar to the first embodiment in construction. In the ninth embodiment, a second terminal unit  9  is provided. Specifically, the second terminal unit  9  is formed as a single-piece, and includes a shank member  92  which has the contact terminal  921  extending through a through hole  14  that is formed in a central region of the base wall  11  between the first and second lateral sides, and first and second limb members  91 , 93  which extend in the first transverse direction (Y) to confront respective ones of the first and third terminal units  2 , 3  in the longitudinal direction (X). 
   While the present invention has been described in connection with what is considered the most practical and preferred embodiments, it is understood that this invention is not limited to the disclosed embodiments but is intended to cover various arrangements included within the spirit and scope of the broadest interpretations and equivalent arrangements.