Abstract:
A door opening circuit comprises pipe-shaped housing and a button which can be moved axially in a housing in order to actuate a circuit component connected to the housing. The button is held in a rest position by a force and can be pushed in a direction opposing said force. Perpendicular to the push path of the bottom and pivotable about a pivot mount. A lever is provided perpendicular to the push path of the button and pivotable about a pivot mount. The lever acts upon a circuit component from a position at a distance to the pivotal mount, whereby the button impinges upon the lever between the pivotable mount and the aforementioned position. Another button is located concentrically to the first button on the reverse side of the housing. The pivotal mount is provided with a lever element. The lever can be moved in the direction of the housing longitudinal axis towards the first button. The other button impinges on the lever element and is held by a force in a rest position and can also be pressed in against the action of said force.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a door opener switch with a tubular housing and a button that can move axially in the housing to actuate a switching mechanism that is connected with the housing, whereby the button can be held in its idle position by a restoring force and can be pushed in against the action of said return force, with a lever that is oriented transversely in the path of movement of the button and can be pivoted by the button around a pivot bearing, which lever acts with a location that is at some distance from the pivot bearing on the switching mechanism, whereby the button contacts the lever between the pivot bearing and the above mentioned location. 
     2. Brief Description of the Related Art 
     Door opener switches require a push button that has a large surface area with a short actuator travel and a flat construction. To achieve this combination, switches of the prior art are equipped with electronic circuit elements, although such elements are sensitive to voltage surges. Voltage surges of this type are common, especially in public transit systems such as railroads, streetcars etc. and can lead to damage to the switches or to disruptions in the operation of the door. 
     To correct this undesirable situation, this same applicant&#39;s EP 0 743 136 describes a door opener switch that combines the advantages of an electronic switch that has a short actuator travel with the advantages of a mechanical switch, in particular the rugged construction of the latter. This door opener switch works satisfactorily. 
     The door opener switches of the prior art described above generally have a collar, the front or back side of which forms a contact surface, and which are mounted in contact with the side surface of a streetcar or similar vehicle. In the prior art, two door opener switches, one inside and one outside, are currently required to operate a door. 
     SUMMARY OF THE INVENTION 
     On the basis of the prior art described above, the object of the invention is a door opener switch of the type described above, with which, in the form of a single switch, a door, for example the door of a public transit vehicle, can be actuated both from inside and from outside. 
     The invention teaches that on the back side of the housing there is an additional button which is oriented concentric to the first button, that the pivot bearing is provided in a lever element which can be displaced in the direction of the longitudinal axis of the housing toward the first button, that the additional button contacts the lever element and that the additional button is held in its idle position by the restoring force and can be pushed in against the action of said restoring force. Therefore the invention also teaches a dense construction that creates a simple and also streamlined double door switch regardless of the actual thickness of the glass. 
     Additional advantageous embodiments of the invention are disclosed. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention is described in greater detail below on the basis of the accompanying schematic drawings, in which: 
     FIG. 1 is a longitudinal section through a door opener switch according to the present invention, 
     FIG. 2 illustrates the function of the door opener switch illustrated in FIG. 1 when the switch is actuated from the front side, 
     FIG. 3 illustrates the function of the door opener switch illustrated in FIG. 1 when the switch is actuated from the back side, and 
     FIG. 4 is a view in perspective of the door opener switch illustrated in FIG. 1 installed in a glass door. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1 shows a longitudinal section through a door opener switch according to the present invention. The switch has a multiple-part, tubular housing which is installed in a mounting surface  1 . The mounting surface  1  can be, among other things, a glass door on a public transit vehicle. The housing consist of, among other things, a rear, hollow, cylindrical jacket  2  and a front cover hood  3 . The cover hood  3  covers, among other things, the jacket support  4  which has at least one opening through which a screw  5  is screwed into a corresponding thread of the rear jacket  2 . In this manner, the door opener switch is fixed in position in the mounting plate  1 . Inserted into the rear jacket  2  is a housing ring  6  which is realized in its internal area so that it is similar to the housing jacket support  4  and forms a symmetrical interior with regard to the housing axis  7  and the switch plane  8  that is perpendicular to said housing axis  7 . 
     Two circuit boards  9  and  10  are oriented parallel to each other and symmetrically with reference to said plane  8 . On these circuit boards  9  and  10  there are, among other things, diodes  11  in a diode array that preferably illuminate the ends  12  and  13  of the door opener switch and improve the visibility of the switch for a user or indicate to the user the operating status of the switch. For this purpose, the housing elements  4  and  6  naturally must be made of a translucent material. The circuits boards  9  and  10  have a through-boring placed around the axis  14 , whereby the axis  14  runs at a short distance of one millimeter, for example, parallel to the longitudinal axis  7  of the housing. A sleeve  15  is inserted into this opening through the circuit boards  9  and  10 , in which sleeve a lever element  16  is mounted. This lever element  16  is movable in the direction of its axis of symmetry  14 . The lever element has, on its front side, a stop collar  17  which forms a stop for the movement of the first lever element  16  into the rear portion of the switch. 
     Instead of a diode array, it is also possible to use optical fibers that, starting from a luminous element, can be routed to different points of the switch underneath a transparent area of the switch. The light that escapes from the ends of the optical fibers then indicates to the user the operating status of the switch. It is thereby possible to bundle different optical fibers at the respective light exit points, that are each fed light from a different colored light source, such as a light-emitting diode, for example. 
     The circuit boards  9  and  10  are inserted in a ring-shaped circuit board carrier  18  which is supported between the housing elements  4  and  6  and against them. They thereby lie on a plurality of small pyramids  38  and when the housing elements  4  and  6  are assembled, they are pressed against them correspondingly. The result is an outward facing surface of the circuit boards  9  and  10  that has a defined axial position. These above mentioned connections are then ultrasonically welded to form a tight, one-piece switch unit. In the sleeve there is an opening through which the connecting cables  28  can be led out sideways. 
     The switch function is initiated by means of a front pushbutton  20  and a back pushbutton  30 , both of which preferably have a rather large diameter. The pushbutton  20  and  30  are connected with the elements  4  and  6  by means of a sealing elastic sealing bellows, which is illustrated in greater detail in FIG.  4 . The pushbuttons  20  and  30  can in particular move along their axis of symmetry  7  toward the center of the housing of the door opener switch. In the idle position of the switch illustrated in FIG. 1, the pushbutton  20 , which is connected with the pushbutton carrier  22 , is in a stop by means of the collar  21 . The same arrangement is used for a push button  30 , which is secured to prevent it from falling out by means of a corresponding stop  34  against the element  6 . 
     The above mentioned lever element  16  has a pivot bearing  23  that can be offset laterally from the axis  14  with respect to the axis  7 , and has among other things a ball socket in which a projection  24  of a lever  25  is mounted. As shown by the additional axis  46  which is shown parallel to the housing axis  7 , the pivot bearing  23  is located at some lateral distance away from the longitudinal axis  7  of the housing, which distance is greater than the distance between the axis of symmetry  14  of the lever element  16  and the longitudinal axis  7  of the housing. This distance can be 2.2 millimeters, for example. The lever  25  has a shaft that runs transversely in which a roller  26  is mounted and impacts a leaf spring  27 . The lever  25  has a lever end  29  which is at a distance from the housing longitudinal axis  7  that is, for example, eight to ten times greater than the distance from the additional longitudinal axis  46 . The lever end  29  is in contact with a spring-loaded actuator cam  31  which is associated with a mechanical switching mechanism  32 . 
     The operation of the electrical door opener when the switch is actuated from the front side is illustrated in FIG.  1 . The same features are identified with the same reference numbers in all the figures. For reasons of simplicity, however, not all the elements are shown in all the figures. The arrow  40  indicates the application of a force to the front push button  20 . When actuated by said force, the push button carrier  22  is displaced toward the longitudinal axis  7  of the housing into the interior of the switch. The above mentioned contact  21  is thereby released. With the movement of the push button carrier  22 , the leaf spring  27  of the push button carrier  22  is likewise displaced, whereby the roller  26  is in contact with the leaf spring. As a result of the lateral offset of the pivot bearing  23 , the roller  26  runs along the leaf spring  27  and moves away from the longitudinal axis  7  of the housing. This happens because the lever element  16 , on account of the contact  17 , can move no farther toward the longitudinal axis  7  of the housing. As a result of the lever arm thereby formed between the roller  26  and the pivot bearing  23 , the lever  25  tilts and the lever end  29  actuates the actuator cam  31  inside the mechanical switching mechanism  32 . 
     This function occurs regardless of whether the force is applied centrally to the longitudinal axis  7  of the housing, as illustrated by the arrow  40 . When the force is applied in the area  41 , FIG. 1 shows that the roller is thereby moved even somewhat more quickly toward the longitudinal axis  7  of the housing. The ring-shaped stop  37 , or when the push button  30  is pressed, the ring-shaped stop  39 , on the opposite side between the front push button carrier  22  and the housing element  4 , forms the fulcrum of such a lateral application of pressure. The same is true if the force is applied on the opposite peripheral area  42 , because the movement of the push button  20  in any case leads to an axial movement of the roller  26  which results in a tipping of the lever  25 . Therefore a central application of force is not necessary; any force applied to the push button  20  that leads to a tipping produces the desired switching result. 
     With reference to FIG. 3, the actuation of the door opener switch from the back side is described below, and is symbolized by the application of force corresponding to the arrow  50 . The rear push button  30  is thereby displaced along the longitudinal axis  7  of the housing into the interior of the door opener switch. This movement results in a detachment of the rear push button carrier  33  with its collar  34  from the corresponding stop of the element  6 . The rear push button carrier  33 , analogous to the front push button carrier  22 , has a leap spring  35 , whereby in this case an additional actuator cam  36  is in contact, which is a projection of the first lever element  16 . As a result of the axial displacement of the push button  30 , the leaf spring  35  and thus, via the additional actuator cam  36 , the first lever element  16  is displaced in its sleeve  15  along the axis  46  and thus parallel to the axis  7 . This displacement leads to a lifting of the collar  17  of the lever element  16  from the circuit board  9 . Because the front push button  20  is in the stop by means of the collar  21  of the front push button carrier  22 , the leaf spring cannot move in the axial direction  7 . In this case, too, the roller  26  is therefore also in a restricted guidance, which as a result of the axial upward movement of the pivot bearing  23  leads to a tipping movement of the actuator cam  24  together with the roller  26 , so that the lever  25  in this case is also tipped and with its lever end  29  actuates the actuator cam  31  of the mechanical switching mechanism  32 . 
     The same observation applies in the event of the application of pressure to the rear push button  30  at the sites  51  and  52 , or in general on the circular edge of the push button. In all cases, the facing part of the collar  34  of the rear push button carrier  33  is in contact, so that a tipping of the rear push button  30  still leads to an axial movement of the first lever element  16 , although with a somewhat shorter stroke. However, that is actually an advantage in the illustrated construction, because even extremely short actuator travels result in a reliable actuation of the mechanical switch element  32  on account of the translation ratio of the lever  25 . 
     Finally, FIG. 4 shows a door opener switch installed in a glass door, in which case the mounting plate  1  can be made of glass, for example. Reference number  53  designates the electrical feed lines that run in a frame  54  of the glass pane  1  to a control circuit. In the view in perspective, the mechanical switching element  32  which is switched by means of the actuator cam  31  is shown particularly clearly. The lever  25  is a rectangular element in which the roller  26  is mounted in a slot that runs transversely. FIG. 4 shows especially clearly the collar  34  of the rear push button carrier  33  as well as the front and rear sealing bellows  55 . 
     The restoring force, however, is generated essentially exclusively by the spring-loaded actuator cam  31  which, after the end of the application of pressure to the front or rear push button  20  or  30 , returns said push button  20  or  30  to its normal position by a return movement of the lever  25 . This sequence of events occurs because on one hand the lever  25  with its cam  24  pushes the lever element  16  with its collar  17  into contact with the circuit board  9 , and on the other hand moves the roller  26  into its idle position, which brings the front push button  20  into contact with the collar  21 . 
     As shown in FIG. 4, the rear jacket  2  forms the rear rosette which covers the switch and can be designed aesthetically and holds the glass pane  1  between it and the element  4 , whereby the front rosette  3  is engaged on this element. In contrast to the configuration illustrated in the accompanying figures, the door opener switch can naturally also be symmetrical with reference to the mounting plate  1 . In general, however, the illustrated embodiment, in which the flat side with the push button  20  faces outward, improves operational safety and reliability, because it is more resistant to tampering and attempted vandalism.