Patent Publication Number: US-4579018-A

Title: Band selector switch

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a band selector switch for use on a television receiver. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a band selector switch capable of proper band selection. 
     According to the present invention, there is provided a band selector switch comprising a rotor having click teeth on its outer circumferential surface, a sleeve rotatably fitted in the rotor and composed of a plurality of axial resilient pieces separated by axial slits defined in the sleeve, the resilient pieces having click grooves defined in inner peripheral surfaces thereof for engaging the click teeth, one of the resilient pieces being deformable radially outwardly, and stop surfaces disposed radially outwardly of those resilient pieces disposed on opposite sides of the one deformable resilient piece for preventing the resilient pieces on opposite sides of the deformable resilient piece from being deformed radially outwardly. 
     The above and other objects, features and advantages of the present invention will become more apparent from the following description when taken in conjunction with the accompanying drawings in which a preferred embodiment of the present invention is shown by way of illustrative example. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a fragmentary perspective view, partly in cross section, of upper and lower cases of a band selector switch of the present invention; 
     FIG. 2 is an exploded perspective view of a rotor and a sleeve; 
     FIG. 3 is a plan view of the rotor and the sleeve as interfitted; and 
     FIG. 4 is a view similar to FIG. 3, but showing click teeth on the rotor spreading the sleeve. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     As shown in FIG. 1, a casing comprises an upper case 1 and a lower case 2 which are secured together in interfitting engagement. The lower case 2 has an array of holes 3. In FIG. 1, a band selector switch includes a rotor 4 rotatably inserted in each of the holes 3. The rotor 4 has a slot defined in its upper surface 4a for insertion therein a jig such for example of a screwdriver, and two pairs of click teeth 4b formed on a lower outer circumferential surface thereof, the click tooth pairs being diametrically spaced from each other. A stop projection 4c is integrally formed with one of the pairs of click teeth 4b at lower portions thereof, the stop projection 4c being thicker than the click teeth 4b. 
     The upper case 1 has on its lower surface an array of sleeves 5 in registry with the holes 3 in the lower case 2. Each of the sleeves 5 has three axial slits 6 dividing the sleeve 5 into three resilient pieces 5a, 5b, 5c. One of the resilient pieces 5a is shorter than the other resilient pieces 5b, 5c to provide a recess 9 in a lower end of the sleeve 5. Each of the resilient pieces 5a, 5c has a pair of axial click grooves 7 defined in its inner peripheral surface for engagement with the click teeth 4b on the rotor 4. The resilient piece 5b has only one axial click groove 7 defined in its inner peripheral surface for engagement with one of the click teeth 4b. 
     When the upper and lower cases 1, 2 are assembled together, the longer resilient pieces 5b, 5c enter a corresponding one of the holes 3 in the lower case 2 with the shorter resilient piece 5a positioned on the upper surface of the lower case 2. The hole 3 has stop surfaces 8 formed therein for preventing the longer resilient pieces 5b, 5c from being deformed radially outwardly. Thus, only the shorter resilient piece 5a is freely deformable in the radially outward direction, but the longer resilient pieces 5b, 5c are prevented at their portions closer to the shorter resilient piece 5a from being opened radially outwardly. 
     Band selecting operation will be described with reference to FIGS. 3 and 4. 
     The rotor 4 is inserted from below into the lower case 2, and the upper and lower cases 1, 2 are assembled together. The rotor 4 has an upper portion projecting from the corresponding sleeve 5 mounted on the upper case 1. At this time, one pair of click teeth 4b on the rotor 4 is received in the click grooves 7 defined in the shorter resilient piece 5a, while the other pair of click teeth 4b is fitted in the click grooves 7 defined in one of the longer resilient pieces 5b, 5c. Therefore, the rotor 4 is retained in a desired position. For band selection, the tip of a jig such as a screwdriver is inserted in the slot 4a in the upper end of the rotor 4, and turned to rotate the rotor 4. The click teeth 4b then move out of the click grooves 7 to spread the sleeve 5 radially outwardly. Continued rotation of the rotor 4 causes the click teeth 4b to engage in adjacent click grooves 7, whereupon the rotor 4 is retained in position again. During such rotation of the rotor 4, the lower resilient pieces 5b, 5c are prevented at their portions closer to the shorter resilient piece 5a from being forced radially outwardly. Accordingly, the click teeth 4b that have been received in the click grooves 7 in the shorter resilient piece 5a will not enter the longer resilient pieces 5b, 5c. This allows the rotor 4 to turn about its own axis in an angular range shown by A in FIG. 3 for proper band selection. The stop projection 4c of a larger thickness formed on the lower portion of one pair of click teeth 4b is positioned in the recess 9 downwardly of the shorter resilient piece 5a. The stop projection 4c will then engage side edge of the longer resilient pieces 5b, 5c to limit the angular interval of the rotor 4 to the range A. Consequently, band selection on this band selection switch construction is rendered more reliable in operation. 
     With the foregoing arrangement, the rotor 4 is limited in its angular movement to a certain angular range by the longer resilient pieces 5b, 5c held against the stop surfaces 8 and also by the stop projection 4c engageable with the side edges of the longer resilient pieces 5b, 5c. Such reliable angular movement of the rotor 4 allows a proper band selecting operation. 
     Although a certain preferred embodiment has been shown and described, it should be understood that many changes and modifications may be made therein without departing from the scope of the appended claims.