Abstract:
A double pole sliding contact trigger switch is disclosed having auxiliary butt contact means for affording sequential actuation of a pair of switches in a single housing. Upon depression of the trigger, a double pole switch is closed by sliding bridging contactors to energize a portable tool motor. Upon further depression of the trigger, a single pole switch is closed by a butting bridging contactor to energize a solenoid in the tool.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to improvements in the trigger and related switch arts. The invention specifically arose from efforts to provide a low cost trigger switch for a hand held portable tool and having two sets of contacts which are sequentially actuated upon finger depression of the trigger to sequentially energize a pair of circuits in the tool, though the invention is of course not limited thereto. 
     SUMMARY OF THE INVENTION 
     An object of the invention is to provide an improved switch affording sequential actuation of a set of sliding contacts and a set of butting contacts in the same housing. 
     Another object is to provide a compact trigger switch of the aforementioned character, particularly designed to enable one contact set to carry high load current, while the other contact set may have a lower current rating. 
     Another object is to provide a trigger switch of the aforementioned character comprising main stationary contacts engaged by bridging contactor means in sliding and wiping relation upon depression of the trigger to close a main circuit, and comprising auxiliary stationary contacts engaged by bridging contactor means in butting relation upon further depression of the trigger to close an auxiliary circuit, and upon release of the trigger the auxiliary circuit opens before the main circuit opens. 
     Another object is to provide a trigger switch of the aforementioned character having mounting means for the auxiliary butting contactor which enable a certain amount of free play at the end of the trigger travel stroke whereby the trigger need not be held absolutely fully depressed in order to maintain closure of the auxiliary circuit, and also having positive disengagement means effective during trigger release at the free play limit to strike the auxiliary butting contactor and positively pull it away from the auxiliary contacts and thus assure opening of the auxiliary circuit. 
     Another object is to provide a trigger switch of the aforementioned character particularly designed for double pole main contacts aligned in a common plane parallel to the direction of trigger travel and perpendicular to a plane containing the auxiliary contacts, the sliding bridging contactor means comprising a pair of main contactors carried by the trigger and biased perpendicularly from the latter&#39;s line of travel into engagement with the main contacts, the butting bridging contactor means comprising an auxiliary contactor carried by the trigger rearwardly of the main contactors and biased rearwardly in the line of travel of the trigger to engage the auxiliary contacts upon further rearward depression of the trigger. 
     Another object is to provide a trigger switch of the aforementioned character having a novel housing enabling mounting of both the double pole main contacts and the auxiliary contacts in the requisite specified orientation, and particular cooperation of some of these contacts. 
     Another object is to provide a trigger switch of the aforementioned character with a novel trigger operator having particular mounting means integrally formed thereon for mounting the main and auxiliary contactors in the requisite orientation to cooperate with the main and auxiliary contacts mounted in the housing and specifically affording sequential actuation. 
     Another object is to provide a trigger switch of the aforementioned character wherein each contactor comprises an elongated squared-C-shaped member having inwardly tucked tips and each mounting means therefor comprises a pair of separated standing ear portions extending from the main body of the trigger and having oppositely outwardly extending turned ends tucked interiorly of and behind the tips of the C-shaped contactor to retain the latter, and a bias spring extending between the spaced mounting ears and bearing between the main body of the trigger and the main body of the C-shaped contactor. 
     Other objects and advantages will hereinafter appear. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side elevation view of a switch constructed in accordance with the invention, with the side housing wall removed. 
     FIG. 2 is like FIG. 1, but shows the switch in an actuated condition. 
     FIG. 3 is a sectional view taken along line 3--3 of FIG. 2. 
     FIG. 4 is an isometric view of the trigger. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     There is shown in FIG. 1 a housing 2 guiding a trigger operator 4 which may be rearwardly slid to an actuated condition, FIG. 2. 
     The housing had double pole stationary contact terminals mounted therein comprising a left set 6 and 8, and a right set, one of which 10 is shown in FIG. 3. As viewed in FIG. 1, the right set is disposed behind left set 6 and 8. Each contact terminal is inverted-L-shaped, having a vertical portion, e.g. 6a, 8a, 10a, for external circuit connection by screws such as 12, FIG. 3. The other leg of the L is a slightly curved horizontal portion, such as 6b, 8b, 10b. The horizontal legs of the contact terminals lie in a common horizontal plane and are engageable by a pair of sliding bridging contactors, to be described hereinafter. These double pole stationary contact terminals are connectable to a high current rated main circuit, such as a motor in a hand held tool in which the switch is mounted. Left set 6 and 8 comprise one pole, and the right set 10 and its mate the other pole, of a double pole main circuit. 
     Also mounted in the housing is a set of single pole auxiliary stationary contact terminals 14 and 16 for connection to an auxiliary circuit, such as a solenoid in the tool for engaging a member to be driven by the motor. Auxiliary contact terminal 14 is inverted-L-shaped having a vertical leg 14a disposed against rear housing wall 2a, FIG. 1, and a horizontal leg 14b disposed on a horizontal section of top housing wall 2b for external circuit connection, FIGS. 1 and 3. Terminal 16 has a vertical portion 16a disposed against rear housing wall 2a and spaced below terminal portion 14a in a common vertical plane therewith extending perpendicularly out of the page, FIG. 1. Terminal 16 also has a lower vertical portion 16b bent forwardly (leftwardly in FIG. 1) 90° from portion 16a to lie flat against the inner edge of main terminal portion 8a, FIG. 3, and share the common external circuit connection thereof. Terminal portions 14a and 16a are engageable by a butting bridging contactor, to be described hereinafter, to close a single pole auxiliary circuit. 
     Trigger operator 4, FIG. 4, is slidably mounted in housing 2 for rearward-forward (rightward-leftward, respectively, as viewed in FIG. 1) rectilinear reciprocal movement. The housing has an upper guiding channel through front opening 2c, FIG. 1, through which the rear inner section 4a, FIGS. 1 and 4, of the trigger reciprocates. The trigger has a front outer section 4b engageable by the finger of the user. A central longitudinal cavity 4c, FIG. 4, extends down into the trigger from above and receives helical compression spring 18 which bears between front cavity wall 4d and a front edge of a central dividing wall 2d of the housing, FIG. 1, to bias trigger 4 outwardly of the housing to the position shown in FIG. 1. Dividing wall 2d is a stationary rigid member integrally formed with the top housing wall and extending downwardly into the guiding channel in the upper section of the housing, FIG. 3. The trigger has a slot 4e cut through its rear end to communicate with cavity 4c and to permit clearance therethrough to central wall 2d.  The bottom wall 4f of slot 4e is sloped rearwardly downwardly to facilitate ease of assembly. 
     When the trigger is in a released position, FIG. 1, wall 2d is in slot 4e, with the front edge of wall 2d extending slightly into cavity 4c to provide a stop against the rear end of bias spring 18. In the depressed position of the trigger, FIG. 2, wall 2d is disposed in cavity 4c as the bias spring has been compressed between front cavity wall 4d and the front edge of wall 2d. Formed on left and right sides of the top of the trigger are grooves, such as 4g, FIG. 4, whose back edge engages a nib 2e protruding down from the top housing wall to stop the forwardly biased movement of the trigger, FIG. 1. 
     Mounted on the bottom of the trigger are a pair of left and right main contactors 20 and 22, FIGS. 1 and 3, engageable in sliding bridging relation with the left set, 6 and 8, and right set, 10 and its mate, of the double pole main circuit stationary contact terminals, respectively. Each of these main contactors is a squared-C-shaped member identically mounted to the trigger. 
     The left underside of the trigger inner section 4a, FIG. 4, has a pair of spaced downwardly extending ear portions 4h and 4i having oppositely outwardly turned ends 4j and 4k protruding beneath inwardly tucked ends 20a and 20b, FIG. 1, of main contactor 20. Helical compression spring 24 is disposed between ear portions 4h and 4i, and bears against the bottom of the trigger body and contactor 20 at the center of the latter&#39;s elongated side 20c. Engagement of ends 20a and 20b with ends 4j and 4k, respectively, limit the downwardly biased movement of contactor 20 and retain the latter on the trigger. Spring 24 provides contact pressure by affording downwardly biased bridging engagement by contactor 20 of main contact terminals 6 and 8, FIG. 2. Right main contactor 22, FIG. 3, is identically mounted and closes the right pole of the main circuit when the trigger is depressed. The rear outwardly turned mounting ear end 4m for contactor 22 is visible in FIG. 4. 
     Mounted on the rear end of the trigger is an auxiliary squared-C-shaped contactor 26, FIG. 1, engageable in butting bridging relation with the single pole auxiliary stationary contact terminals 14 and 16. The mounting means for auxiliary contactor 26 is comparable to that for main contactors 20 and 22. The rear end of the trigger has on its left side, FIG. 4, a pair of spaced rearwardly extending ear portions 4n and 4p  having oppositely outwardly upwardly and downwardly turned ends 4q and 4r protruding beneath inwardly tucked ends 26a and 26b of auxiliary contactor 26, FIG. 1. Helical compression spring 28 is disposed between ear portions 4n and 4p, and bears against the rear end of the trigger body and contactor 26 at the center of the latter&#39;s elongated side 26c. Engagement of ends 26a and 26b with ends 4q and 4r, respectively, limit the rearwardly biased movement of contactor 26 and retain the latter on the trigger. 
     FIG. 1 shows the switch in an off condition. Elongated side 20c of main contactor 20 is in engagement with main contact 6b, and main contactor 22 is in engagement with the main contact on the right side of the housing across (behind in FIG. 1) from contact 6b. Upon depression of the trigger, left side main contactor 20 slides along left side main contact 6b and into sliding bridging engagement with left side main contact 8b, FIG. 2, to close the left pole of the main circuit by completing a circuit from terminal 6 through left side bridging contactor 20 to terminal 8. The right side main contactor 22 simultaneously engages right side main contact 10b, FIG. 3, to close the right pole of the main circuit. Further depression of the trigger causes elongated side 26c of auxiliary contactor 26 to buttingly engage auxiliary contacts 14a and 16a to close the single pole auxiliary circuit by completing a circuit from terminal 14 through bridging contactor 26 to terminal 16. 
     The switch is provided with a certain amount of free play at the rear end of the trigger travel stroke so that the trigger need not be absolutely fully depressed in order to maintain closure of the auxiliary circuit. This is especially important in a trigger switch actuated by user applied finger pressure. The free play is enabled by the auxiliary contactor and its mounting means on the rear end of the trigger, particularly contactor sides 26d and 26e and ears 4n and 4p. The lineal length of free play is determined by the length of ears 4n and 4p in combination with the length of auxiliary contactor sides 26d and 26e. Even if the user does not keep the trigger firmly and fully depressed as in FIG. 2, bias spring 28 will compensate possible slack in user applied force and furnish the requisite contact pressure. 
     Upon trigger release, auxiliary contactor 26 remains in engagement with auxiliary contacts 14a and 16 a until a predetermined point in the return forward travel of the trigger, which is the limit of the free play. Turned ear ends 4q and 4r then strike inwardly turned ends 26a and 26b to positively pull auxiliary contactor 26 away from auxiliary contacts 14a and 16a, thus providing positive disengagement and assuring opening of the auxiliary circuit. 
     It is preferred that ears 4n and 4p to made long enough relative to contactor sides 26d and 26e so that at the end of the rearward trigger stroke, FIG. 2, the rear ends of ears 26d and 26e will strike elongated contactor side 26c before inwardly turned contactor ends 26a and 26b strike the trigger body. 
     Ears 4n and 4p and/or contactor sides 26d and 26e are made long enough so that elongated auxiliary contactor side 26c, FIG. 2, engages auxiliary contacts 14a and 16a before main contactor side 20d can strike auxiliary contact 16a. This insures that rearward trigger depression will not be halted prematurely, before closure of the auxiliary circuit. It is preferred that the rear ends of ears 26d and 26e strike elongated contactor side 26c before main contactor side 20d can reach auxiliary contact 16a, to provide positive direct closure of the auxiliary circuit upon full trigger depression without relying on the bias of spring 28. 
     In the embodiment shown, terminal 16 shares the same external circuit connection with terminal 8 because of the contiguous mounting, FIG. 3, of terminal portion 16b, terminal portion 8a and screw 12. The auxiliary circuit could also be completed between terminals 14 and 6 because in the on condition of the switch, FIG. 2, a circuit is completed from terminal 14 through bridging contactor 26 through terminal 16 through terminal 8 through contactor 20 to terminal 6. A modification would be to provide terminal 16 with its own independent external circuit connection. 
     In one particular application of the switch, the main circuit draws higher current relative to the auxiliary circuit. Thus the double pole main contacts are preferred, and the sliding wiping action is desirable, as well as the shearing of contact welds. 
     The lower rated auxiliary circuit only requires a single pole, and butt contacts are sufficient. There is of course room for a double pole auxiliary circuit by adding a contactor and mounting means therefor to the right rear end 4s, FIG. 4, of the trigger. It should be noted that the auxiliary ciruit could handle high current if desired because turned ends 4q and 4r provide positive contact break upon release of the trigger as they directly engage tucked ends 26a and 26b to pull contactor 26 away from terminal portions 14a and 16a. 
     It is recognized that various modifications are possible within the scope of the appended claims.