Snap-in trigger
This application is a continuation of Ser. No. 07 249,374, filed on Sep. 26, 1988, which is now U.S. Pat. No. 4,917,303. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to improvements in the construction and assembly of pivotal levers, generally, and to triggers for sprayers, in particular. The trigger of this invention can be integrally molded and includes structural features which permit virtually instantaneous snap-in attachment to a pivot base, such as to the housing of a sprayer, for secure, pivotal attachment. 
     Pivotal levers have widespread utility in industrial articles of manufacture, for example, as triggers in sprayers. Such levers should be pivotally attached securely to a base, such as, for example, a trigger to a sprayer housing. The design and construction of these levers is in response to a number of competing forces. For example, there is a need for low cost manufacture of the trigger element itself, for low cost trouble free assembly, i.e. attachment of the trigger to a spray head, for smooth operation, once assembled, and for long lasting trouble free operation. 
     All these considerations must be addressed effectively in order to provide the manufacturer of finished assemblies with a product of truly competitive cost, and the consumer user with a product of economic, completely satisfactory, trouble free construction. 
     2. Description of the Prior Art 
     There have been many suggestions for improving the design, construction, and assembly of such levers. For example, the McKinney U.S. Pat. No. 4,161,288 suggests retaining the trigger by providing a spiral chamber in the trigger into which pivot lugs on the sprayer housing can be maneuvered. 
     The Martin U.S. Pat. Nos. 4,480,768, 4,489,890, and 4,503,998 are sister patents which suggest providing the pivot attachment elements on flexible portions of both the trigger and sprayer housing, so that both of these sets of elements can flex during mating attachment, in order not to excessively damage the pivot lugs, etc. However, both sets of the flexible portions remain flexible, after attachment of the trigger to the sprayer, and these patents leave unresolved, the problem of dislodgement of the pivot lugs from their respective sockets, during forcible pivoting operation of the trigger due to the flexibility of the lug-carrying portions of the trigger and the sprayer. 
     The Tada U.S. Pat. No. 4,153,203 suggests providing a lever (trigger) with flexible lateral walls carrying cylindrical pivot lugs, and addresses the problem of disengagement during pivotal operation by teaching to provide rigid &#34;stopper boards&#34; on the body which project from the body to bear against the insides of those flexible portions of the trigger which carry the pivot elements. This is purported to prevent the walls carrying the pivot elements from being thrown inward, thereby preventing unmating of the respective pivot lugs and sockets. This patent is silent, however, as to how, on one hand the rigid &#34;stopper boards&#34; can, in the same configuration, allow assembly movement or positioning of the trigger unit to bring the pivot lugs into a pre-mating, coaxially aligned orientation with their corresponding sockets on the sprayer housing for mating of these pivotal linking elements without damage, and yet after mating, prevent the movement of these same flexible elements to that same pre-mating, coaxially aligned assembly position which would then allow disengagement of the pivot elements. 
     There is a need to provide the art with an economical snap-in trigger which will provide secure, trouble free operation for the life of the sprayer, and which allows virtually instantaneous attachment to the sprayer housing, either manually or by machine. 
     SUMMARY OF THE INVENTION 
     The present invention provides a snap-in lever which will not be damaged during the assembly process to a sprayer, and which will maintain a secure assembled position to function properly for the life of the sprayer. 
     In accordance with a preferred aspect of the present invention, the lever, or trigger, is provided with three flexible members, e.g., panels. Two of these members, or panels are bilateral, and carry pivot structure for mating with corresponding elements on a base, or sprayer housing, and for providing pivotal attachment thereto. The third flexible member or panel constitutes a locking system, part of which is transverse to the bilateral panels, and is capable of flexing or hinging into two positions. The first position is one in which the third panel will not interfere with the motion of the pivot structure on the flexible bilateral panels prior to attachment to the base. The second position, the locking position, is one in which at least a portion of the third, i.e., transverse panel is positioned between the flexible bilateral panels, and prevents relative movement of the bilateral panels towards each other, thereby positively locking the pivot structure in proper position, by preventing disengagement of the mating pivot elements from the base. 
     Hence, as used herein, the term &#34;locking&#34; as applied to the flexible bilateral members or panels doesn&#39;t imply that the trigger is rendered immovable, but just that the pivot structure are secured in proper operating pivotal position. 
     In a more preferred aspect of this invention, the lever, or trigger, is a unitary molded element fashioned from strong, resilient, flexible polymer. In such a preferred embodiment, the third panel is molded in the first position referred to above, namely, in a position in which it will not interfere with the inward flexing of the pivot structure bearing bilateral panels. The third, locking, element is furthermore maintained in that open position during shipping, packaging, or other preassembly handling by means of integral, frangible, molded bridge webs extending between portions of the third panel, and respective adjacent portions of the bilateral panels. These integral webs are easily ruptured upon the application of sufficient force to accomplish hinging, or pivoting of the third panel into its locking position between the bilateral panels, during the final instant of assembly attachment of the lever to its base. 
     In addition, the third hinged panel, and the body of the lever is provided with a second locking arrangement for maintaining the third panel in the second, or locking position, in opposition to tis tendency, due to molecular memory, to spring back to the first, open, molded position. 
     According to the invention, there is provided a trigger for mounting to a trigger sprayer housing having trigger pivot mounting means therein, said trigger comprising an elongate body having a top portion, said top portion including (a) first and second flexible side panels each carrying pivoting structure for mating with the trigger pivot mounting means and (b) flexible, movable locking means for locking said pivot structure in pivotal engagement with the trigger pivot mounting means when said locking means are moved relative to said side into a locking position. Further according to the invention, there is provided a pivot assembly in a trigger sprayer comprising a trigger having an elongate body and a top portion and a sprayer housing having a recess, said assembly comprising trigger pivot mounting means in said recess and said top portion of said trigger body including (a) first and second flexible side panels each carrying pivoting structure for mating with the trigger pivot mounting means and (b) flexible locking means for locking said pivot structure in pivotal engagement with the trigger pivot mounting means when said locking means are moved relative to said side panels into a locking position. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a trigger sprayer assembly attached to a container. 
     FIG. 2 is a perspective view of a detached unitary molded trigger constructed in accordance with the teachings of the present invention. 
     FIG. 3 is an outside elevational view of the trigger of FIG. 2, taken along line 3--3 of FIG. 2. 
     FIG. 4 is an inside elevational view of the trigger of FIG. 2 taken along line 4--4 of FIG. 2. 
     FIG. 5 is a cross sectional view of the trigger of FIG. 2 taken along line 5--5 of FIG. 4. 
     FIG. 5a is a top view of the trigger taken approximately along line 5a--5a of FIG. 5. 
     FIG. 6 is a perspective view of the trigger and a sprayer housing illustrating the alignment of the trigger and the sprayer housing, prior to assembly insertion of the trigger into the sprayer housing. 
     FIG. 7 is a perspective view illustrating partial insertion of the trigger into the sprayer housing. 
     FIGS. 8a, 8b, and 8c are fragmentary, cross sectional views of the trigger and the sprayer housing taken along line 8--8 of FIG. 7, and illustrates sequential positions of elements during the mating insertion of the trigger into the sprayer housing or base. 
     FIG. 9 is a perspective, cut-away view of the top of the trigger and shows the trigger in fully inserted position, pivotally attached to the sprayer housing or base. 
     FIG. 10 is a fragmentary cross sectional view of the trigger and sprayer housing taken along line 10--10 in FIG. 9, illustrating the attached, unlocked configuration of the trigger with the third, or hinged panel shown in the open position. 
     FIG. 11 is a fragmentary cross sectional view of the trigger and sprayer housing as shown in FIG. 10, except that the third, hinged panel is shown moved into its locking position. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     The broad aspects of the present invention are illustrated herein by reference to a specific preferred embodiment, namely, by reference to a trigger sprayer comprising a trigger and a sprayer housing. This is not intended to limit the scope of the invention, which is defined in the appended claims. 
     Considering FIG. 1, a trigger sprayer assembly 20 is shown comprising a sprayer housing 25, and a trigger 30. The trigger-sprayer assembly 20 is shown attached to a container 35 by means of a screw cap 40, rotatably attached to the sprayer housing 25. 
     A dip tube 45, other elements 50 associated with a pumping mechanism, and a nozzle 55 are not part of the novel aspects of the present invention, and, for the purposes of this specification, are to be considered conventional. Hence, these structures, and other operational elements associated with the sprayer housing 25, apart from the novel lever, or trigger 30 and associated elements on the sprayer housing or base, will not be described in any further detail. 
     Turning now to the details of construction of the trigger 30, a preferred illustrated embodiment is an integral molded unit comprising side panels 60, 65 transversely joined by stiffener ribs 70, 72, and by front panel 75. (See FIGS. 4 and 9) Side panels 60, 65 include respective flexible end portions 80, 85, and the front panel 75 includes flexible locking end panel or flap 90. Side panels 60, 65 are also stiffened by respective ribs 81, 86. These ribs 81, 86 are preferably of a wedge shape, perhaps best illustrated in FIG. 5a, in order to maintain the correct spacing of side panels 60, 65 for assembly purposes, and yet do not interfere with the flexing of flexible end portions 80, 85 towards each other. It is noted that in the illustrated embodiment, the direction of placement of ribs 81, 86 is generally parallel to the axis of the flex or bend of side panels 60, 65 in the vicinity of flexible end portions 80, 85. 
     Flexible end portions 80, 85 carry pivot pins or lugs 100, and 105, respectively, for mating with respective, corresponding sockets 110 and 115 (see FIG. 6) in the sprayer housing 25. (In an alternative embodiment, not shown, the pivot lugs can be carried by the spray head 25, and the pivot sockets can be carried by the trigger, without departing from the spirit or scope of this invention.) 
     It is noted that pivot lugs 100, 105 are truncated, so that its walls include a round portion 101, 106, and an opposite ramp portion 102, 107. (See FIGS. 3 and 4.) The ramp portions 102, 107 are positioned to encounter the sprayer housing 25 during insertion of the trigger 30 into the sprayer housing 25, during assembly. 
     Two slots 120 (FIG. 2) are formed in the inner wall surface of the flexible portion 80, 85 of the side wall 60 and side wall 65, respectively, behind lugs 100, 105. 
     It is noted that in FIG. 1 the inged end panel 90 of front panel 75 is positioned spaced-apart from the vicinity of pivot elements (lugs 100, 105) on th flexible end portions 80, 85 of the side panels 60, 65. 
     A flexible web bridge 125 or hinged area 125 of reduced thickness between the end panel 90 and front panel 75 maintain 5 this configuration of the trigger 30 during the preinsertion and assembly in order to provide, at the moment of assembly insertion of the trigger 30 into the sprayer housing 25, flexible free ends 80, 85 which can be easily flexed towards each other. Should the hinged end panel 90 be forced out of the &#34;open&#34; configuration shown in FIG. 1, and into the &#34;locking&#34; configuration shown in FIG. 11, prior to insertion assembly of the trigger 30 to the sprayer housing 25, it would be impossible to flex the free end portions 80, 85 inwardly and thus pivot lugs 100, 105 would be severely damaged. 
     Referring now to FIG. 6, trigger 30 is shown aligned for insertion, during assembly, into the sprayer housing 25. Both sockets 110, 115 are visible in FIG. 6, and are shown located in respective rigid side panels 130, 135. Fixed maintenance of rigid panels 130, 135 in the exact spaced-apart dimensions shown, is assisted by integral end face 140 of sprayer housing 25 and recesswall 147 which extends between panels 130, 135, and which assist in preventing even the slightest movement of side panels 130, 135 to or from each other. 
     Referring to FIG. 7, trigger 30 is shown partially inserted between spray head panels 130, 135, and FIGS. 8a, 8b, and 8c show relationships between elements during the continuing insertion of the trigger 30 into the sprayer housing 25. 
     In FIG. 7, the significance of ramp portions 102, 107 of pivot lugs 100, 105 becomes clear. Hence, as the trigger 30 is moved in the general direction of the arrow, so are the ramp portions 102, 107 of lugs 100, 105 which first encounter the ends of sidewalls 130, 135. Continued inward insertion of the trigger 30 into the recess 145, defined by wall 147, sidewalls 130, 135 and end wall 140 and associated parts of the sprayer housing 25, causes the &#34;ramping-in&#34; of the flexible end panels 80, 85 towards each other, allowing lugs 100, 105 to pass between rigid sidewalls 130, 135 of the sprayer housing 25, without damage. 
     Alternatively, manual or machine pressure against the outer surfaces of flexible ends 80, 85 in the vicinity of lugs 100, 105 causes the inward flexing which will allow lugs 100, 105 to clear and enter recess 145, and to travel within recess 145 easily. 
     Also, as an alternative, the trigger 30 can be mated with the sprayer housing 25 by insertion into recess 145 from other directions, for example, along the path indicated by the arrow marked &#34;B&#34; in FIG. 7. 
     FIG. 8a shows the initial relationships, as the trigger 30 is first inserted, along the arrow marked &#34;A&#34; in FIG. 7, and to the extent shown in FIG. 7. In this illustration, the ends of flexible bilateral wall panels 80, 85 are travelling within the recess 145 formed by rigid side panels 130, 135 and connecting inner wall 147 of sprayer housing 25. Cradle arms 150, 155 define respective rigid projections extending from wall 147 of the sprayer housing 25 into the recess 145 region between the rigid sidewalls 130, 135, and are spaced apart from the rigid sidewalls 130, 135 to define respective slots 160, 165. (A cradle arm is also illustrated in FIG. 9.) 
     In FIG. 8a the respective ends 161, 166 of trigger wall panels 60, 65 are shown entering respective slots 160, 165 defined by bilateral cradle arms 150, 155. 
     It is at this point that it is important, for high speed machine assembly, for example, that the spaced-apart dimension of the ends 161, 166 be accurate to match the spaced-apart dimension of respective slots 160, 165, and it is noted that ribs 81, 86 help assure that accuracy at the moment of insertion of the trigger 30 into recess 145 of the sprayer housing 25. 
     FIG. 8b illustrates the limited inward flexing of the flexible side panel portions 80, 85 as pressure against ramp portions 102, 107 of respective lugs 100, 105 wedge flexible panels 80, 85 inwardly towards each other, thereby allowing the lugs 100, 105 to clear rigid sidewalls 130, 135 and move unharmed between rigid sidewalls 130, 135. 
     The positioning of the cradle arm, or stop arm elements 150, 155 adjacent sidewalls 130, 135 to define channels or slots 160, 165 to limit the inward flex of the trigger flexible sidewalls 80, 85 is optional. 
     However, this arrangement of the arms 150, 155 does provide a more positive &#34;snap&#34; when the respective pivot elements 100, 105, and 110, 115 are coaxially aligned and mated, by biasing sidewalls 80, 85 toward the mated position, as shown in FIG. 8c. These cradle arms, in the illustrated position, thereby facilitate achievement of the spaced-apart dimension between flexible panel portions 80, 85, for the ready entry of hinged panel 90 therebetween, after mating of respective lugs 100, 105 with respective sockets 110, 115, for the locking configuration shown in FIG. 8c. 
     Cradle arms 150, 155 also serve another important function which will be described more fully in connection with the description of FIG. 11; namely, they serve as stop means to prevent the hinging motion of the hinged end panel 90 beyond the proper locking position between flexible panels 80, 85 in the vicinity between pivot lugs 100, 105. 
     In FIG. 9, the relative position of only one cradle arm 155 is shown for the purpose of simplifying and clarifying the illustration of the positioning of the trigger 30 in pivotally mated position with respect to the sprayer housing 25. The relationships inherent in FIG. 9 are more fully developed immediately hereinafter with the aid of the cross sectional views of FIGS. 10 and 11. 
     As shown in FIG. 10, the hinged end panel 90, and its columnar rib 92 are positioned spaced-apart from the vicinity of the pivot elements, e.g. pivot lug 105, pivot socket 115, and the integral bridge web 125 maintains the hinged end panel 90 in its &#34;open&#34; configuration. Flexible panels 80, 85 can be flexed inwardly towards each other while the hinged, locking end panel 90 is in this position. 
     FIG. 11 illustrates the configuration prevailing after end panel 90 is moved to a locking position in which the columnar rib 92 is positioned between flexible end walls 80, 85 in the vicinity of the pivot elements, e.g. pivot lugs 100, 105. It is clear from a comparison of FIG. 10 and FIG. 11, that the slots 120 on the respective inner faces of flexible panels 80, 85 of side walls 60, 65 and 180, 185 extending from the respective ends of columnar lock rib 92 serve as a secondary locking arrangement to secure the flexible hinged, locking, end panel 90 in its locking position to provide the primary locking function, namely, keeping flexible panels 80, 85 apart to such an extent that lugs 100, 105 will never leave corresponding respective sockets 110, 115 during operation, or otherwise. The end panel 90 is hinged by the reduced thickness hinge area 125 between the panel 90 and the front panel 75. During assembly or use of the trigger sprayer, cracks will sometimes occur in the hinge area 125. However, with the locking end panel 90 locked in place, such cracks do not adversely affect the trigger 30 or the functioning thereof. 
     Detents 180, 185 are also tapered, or &#34;ramped&#34; at 187 to facilitate their entry between panel ends 80, 85, during the locking movement indicated by the arrow c in FIG. 11 and into respective retaining slots 120. The retaining slots 120 serve to lock the detents 180, 185 in place thereby to lock the end panel 90 in the assembled positions. 
     Thus, the hinged, locking end panel 90 is shown in its open, unlocked configuration in FIGS. 2-10, and is shown in its 35 locked configuration in FIGS. 1 and 11. 
     The role of the cradle arms e.g. 150, namely, preventing overshoot of the flexible, locking end flap 90 beyond the proper locking configuration is clear from FIG. 11. 
     Hence, attachment of the snap-in lever, or trigger 30 of this invention to a base or sprayer housing 25, in accordance with this invention, is virtually instantaneous. 
     Mating of the trigger 30 and the sprayer housing 25 can take place by movement of the trigger 30 into recess 145, from any appropriate direction, e.g. along the lines identified by Arrow A, or Arrow B, in FIG. 9. 
     Positioning of the trigger 30 into the recess 145 approximately as shown in FIG. 9, and moving the trigger relatively towards the sprayer housing 25 along the path indicated by the arrow &#34;A&#34; in FIG. 9, causes the ends 161, 166 of trigger side panels to enter slots 160, 165, respectively, and tapered portions 102, 107 of lugs 100, 105 to engage the ends of rigid sidewalls 130, 135. Continued application of pressure in the mating direction results in inward flexing of the trigger side panel portions 80, 85 towards each other. This allows the lugs 100, 105 to easily pass between sidewalls 130, 135 and to be moved easily into a position of coaxial alignment with sockets 110, 115. The lugs 100, 105 then &#34;snap&#34; into sockets 110, 115 to pivotally attach the trigger 30 to the sprayer housing 25. Pushing hinged locking end panel 90 inward, e.g. along the arrow in FIG. 11, results in the locking of the pivot lugs 100, 105 and sockets 110, 115 in the mating, pivoting configuration, and also automatically secures the hinged end panel 90 into that locking configuration. 
     Hence, this assembly operation can be done almost instantaneously by hand, or by machine. 
     Operation of this lever system by forcibly moving the unattached end of the trigger 30 towards the sprayer housing 25, brings the rounded portions 101, 106 of the lugs 100, 105 to bear against the opposing rounded bearing surfaces of sockets 110, 115 and causes movement of the pump mechanism 50 with mechanical advantage. Hence, providing for truncated portions 102, 107 of pivot lugs 100, 105 doesn&#39;t adversely affect the smooth bearing cooperation between the lugs 100, 105, and their corresponding respective sockets 110, 115. Nor does that cause any tendency for the pivot lugs 100, 105 to jump or wedge out of the sockets 110, 115, because it is only the rounded surfaces 101, 106 of the lugs 100, 105 which will bear against the bearing surfaces of sockets 110, 115, during forcible, pivoting operation of the trigger Note that if desired the truncated ramp surfaces 102, 107 can extend angularly transversely of the trigger 30 and rearwardly toward the sprayer housing 25 or directly upwardly toward the housing 25 on or at an inclined angle to the vertical, e.g., 45 toward the housing depending on the choice of direction of insertion of the top portion of the trigger 30 into the sprayer housing 25. One preferred direction of insertion is shown by the arrow B in FIG. 7. In this assembly method, the trigger 30 is first located a few millimeters below and in front of the housing 25. Then, the ramp 102, 107 on pivot lugs 100, 105 are moved angularly upwardly past the inside corner of the panels 130, 135 into the recess 147. 
     In addition, the close abutment of surfaces of the trigger side panels 60, 65 to opposing surfaces of rigid panels 130, 136 of spray head 25, as well as the presence of ends 161, 166 of side panels 60, 65 in slots 160, 165, and the stiffener ribs 81, 86 on side panels 60, 65, all cooperate to prevent wobble or twisting of trigger 25, after assembly, when twisting, or side-to-side forces are applied to the free end of trigger 25, and to reduce the forces applied on pivot lugs 100, 105. 
     From the foregoing description, it will be apparent that the pivot assembly of the trigger 30 to the sprayer housing 25 provides a number of advantages, some of which have been described herein and others of which are inherent in the assembly. Furthermore, it will be apparent that modifications can be made to the pivot assembly without departing from the teachings of the invention. Accordingly, the scope of the invention is only to be limited as necessitated by the accompanying claims.