Abstract:
A vibration switch includes an electric contact body which is movably disposed in an accommodation chamber of a housing in an upright direction. A biasing member holds and restrains the contact body from moving towards a lower inner wall surface of the housing. A switching unit includes a contact member extending into the chamber, and is placed in one of switch-on and switch-off states in response to movement of the contact body relative to the contact member as a result of an inertial force of the contact body when the housing is jerked to move upwards.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    This invention relates to a vibration switch, more particularly to a vibration switch with an electric contact body which is movable to engage or disengage from a contact member of a switching unit by means of a biasing member so as to place the switching unit in one of switch-on and switch-off states.  
           [0003]    2. Description of the Related Art  
           [0004]    Referring to FIG. 1, a conventional vibration switch  1 , which is applied to a warning device or a step-counting device, is shown to include a metal swing shaft  101  which has a pivot end  102  mounted pivotally on a circuit board  105 , and a swing end  103  with a metal head  104 . A metal pad plate  106  is secured on the circuit board  105  adjacent to the head  104 . A string-shaped biasing member  107  is connected to the swing shaft  101 . When the switch is jerked by means of a force (F), the swing end  103  will swing to move the head  104  to punch the pad plate  106  so as to place the switch  1  in an on state. By virtue of the biasing action of the biasing member  107 , the swing end  103  can swing back to remove the head  104  from the pad plate  106  so as to place the switch  1  in an off state. However, the swing shaft  101  is bulky, and has a relatively large number of components, thereby resulting in inconvenient carrying and packaging and manufacturing costs.  
         SUMMARY OF THE INVENTION  
         [0005]    The object of the present invention is to provide a vibration switch which has a simple construction and compact size, and which can be fabricated at a relatively low cost.  
           [0006]    According to this invention, the vibration switch includes a housing which is adapted to be mounted on a support in an upright direction. The housing has upper and lower inner wall surfaces which are spaced apart from each other in the upright direction, and a surrounding wall which is interposed between and which cooperates with the upper and lower inner wall surfaces to confine an accommodation chamber. An electric contact body is disposed in the accommodation chamber and is movable in the upright direction. The contact body has electrically conductive uppermost and lowermost ends opposite to each other in the upright direction. A biasing member has an engaging end which is disposed to engage one of the upper and lower inner wall surfaces, and a holding end which is disposed opposite to the engaging end and which holds the electric contact body such that the uppermost and lowermost ends are nearest to the upper and lower inner wall surfaces, respectively. By means of a biasing action against the weight of the electric contact body, the holding end restrains the electric contact body from moving towards the lower inner wall surface. A switching unit includes a contact member which is disposed to extend into the accommodation chamber such that the switching unit is placed in one of switch-on and switch-off states in response to movement of the electric contact body in the upright direction relative to the contact member as a result of an inertial force of the electric contact body when the housing is jerked to move upwards. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]    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:  
         [0008]    [0008]FIG. 1 is a schematic view of a conventional vibration switch;  
         [0009]    [0009]FIG. 2 is an exploded perspective view of the first preferred embodiment of a vibration switch according to this invention;  
         [0010]    [0010]FIG. 3 is a sectional view of the first preferred embodiment;  
         [0011]    [0011]FIG. 4 is a sectional view of the first preferred embodiment when vibrated;  
         [0012]    [0012]FIG. 5 is a sectional view of the second preferred embodiment of a vibration switch of this invention;  
         [0013]    [0013]FIG. 6 is a sectional view of the second preferred embodiment when vibrated;  
         [0014]    [0014]FIG. 7 is a sectional view of the third preferred embodiment of a vibration switch of this invention; and  
         [0015]    [0015]FIG. 8 is a sectional view of the third preferred embodiment when vibrated. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0016]    Referring to FIGS. 2 and 3, the first preferred embodiment of a vibration switch  10  according to the present invention is shown to comprise an elongate housing  11 , two ball-shaped electrically conductive contact bodies  13 , an electrically conductive biasing member  12 , and a plug member  14 .  
         [0017]    The housing  11  is adapted to be mounted on a support (not shown) in an upright direction, and is made from an insulating material. The housing  11  has a lower inner wall surface  114  and a surrounding wall  111 , which cooperatively confine an accommodation chamber  115  with an upper opening end  113 . The surrounding wall  111  is formed with a shoulder  116  adjacent to the upper opening end  113 .  
         [0018]    The plug member  14  is made from an electrically conductive material, and has a top surface  141  which is formed with an electric contact terminal  142  extending upwardly therefrom, and a surrounding wall with an annular guiding protrusion  145  for facilitating fitting insertion of the surrounding wall into the upper opening end  113  such that a lower surface  143  of the plug member  14  abuts against the shoulder  116  to close the upper opening end  113 .  
         [0019]    The contact bodies  13  are disposed in the accommodation chamber  13 , and are superimposed upon each other in the upright direction so as to define uppermost and lowermost ends which are opposite to each other in the upright direction and which are proximate to the upper opening end  113  and the lower inner wall surface  114 , respectively. The contact bodies  13  are movable together in the upright direction.  
         [0020]    In this embodiment, the biasing member  12  is a tension coil spring, and has an engaging end  121  which engages the lower surface  143  when the lower surface  143  abuts against the shoulder  116  and which is in the form of a loop with a first dimension so as to permit the contact bodies  13  to pass therethrough, and a holding end  122  which is in the form of a loop with a second dimension that is smaller than the first dimension so as to hold the contact bodies  13 .  
         [0021]    An electric contact member  117  is disposed to extend into the accommodation chamber  115  via a through hole  118  in the housing  11  to cooperate with the electric contact terminal  142  to form a switch unit.  
         [0022]    By means of a biasing action of the coil spring  12  against the weight of the electric contact bodies  13 , the holding end  122  can restrain the lowermost end of the electric contact bodies  13  from moving towards the contact member  117  so as to break an electrical connection between the contact terminal  142  and the contact member  117 , thereby placing the switch in an off state. As shown in FIG. 4, once the housing  11  is jerked to move upwards by means of a force (F), the contact bodies  13  will move downwards as a result of an inertial force of the contact bodies  13  so as to contact with the contact member  117 , thereby making the electrical connection between the contact terminal  142  and the contact member  117 .  
         [0023]    As illustrated, the vibration switch of this invention has a simple construction that is easy to fabricate at a relatively low manufacturing cost and that has a compact size to facilitate carrying.  
         [0024]    Referring to FIGS. 5 and 6, the second preferred embodiment of a vibration switch  20  is shown to include an electrically conductive housing  21 , an insulating plug  24 , a ball-shaped electrically conductive contact body  23 , and an electrically conductive biasing member  22 . The housing  21  has an upper inner wall surface  213  and a surrounding wall  215 , which cooperatively confine an accommodation chamber  211  with a lower opening end  212 . An electrically contact terminal  214  is integrally formed with and extends upwardly of the upper inner wall surface  213 . The plug  24  is fittingly inserted into the lower opening end  212 , and has an electrically conductive plate member  241  which is mounted on an end wall surface  243  thereof. An electric contact member  242  extends through the plug  24 , and passes insulatingly through the plate member  241  into the accommodation chamber  211 . The biasing member  22  is a compression coil spring and is in a loop form to permit the contact member  242  to pass therethrough. The biasing member  22  has an engaging end which engages the plate member  241 , and a holding end which holds and which biases the contact body  23  to abut against the upper inner wall surface  213  so as to restrain the lowermost end of the contact body  23  from moving toward the contact member  242 , thereby breaking the electrical connection between the contact terminal  214  and the contact member  242 . Once the housing  21  is jerked to move upwards by means of a force (F), the contact body  23  will move downwards as a result of an inertial force of the contact body  23  so as to contact with the contact member  242 , thereby making the electrical connection between the contact terminal  214  and the contact member  242 .  
         [0025]    Referring to FIGS. 7 and 8, the third preferred embodiment of a vibration switch  30  is shown to include an electrically conductive housing  31 , an insulating plug  34 , a ball-shaped electrically conductive contact body  33 , and an electrically conductive biasing member  32 . The housing  31  confines an accommodation chamber  311  with an upper opening end  312  for fitting insertion of the plug  34 . An electric contact member  341  extends through the plug  34  into the accommodation chamber  311 . An electric contact terminal  314  extends downwardly of and is formed integrally with a lower inner wall surface  313  of the housing  31 . The biasing member  32  is a compression coil spring and is in a looped form. The biasing member  32  has an engaging end which engages the lower inner wall surface  313 , and a holding end which holds and biases an uppermost end of the contact body  33  to abut against the contact member  341  so as to make the electrical connection between the contact terminal  314  and the contact member  341 . Once the housing  31  is jerked to move upwards, the contact body  33  will move downwards to disengage from the contact member  341 , thereby breaking the electrical connection between the contact terminal  314  and the contact member  341 .  
         [0026]    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.