| 摘要 |
<p>1285337 Push-button switches JOSEPH LUCAS (INDUSTRIES) Ltd 12 Sept 1969 [23 Sept 1968] 45076/68 Heading HlN A three-position successive-actuation switch comprises a body 11 in which a slider 14 is urged to the end position shown by a spring 23 (acting between surfaces 11a and a button 21) and carries a contact 15 which in a second position of the switch interconnects fixed contacts 16 and 17 and in a third position interconnects fixed contacts 16, 17 and 18, the slider being releasably retained in the third and second positions, respectively, by means of two pins 25 (and 26, Fig. 2, not shown) carried thereon by spring blades 24 and which co-operte, respectively, with "heart"-type cam formations (27, 28) spaced laterally and longitudinally inside body 11. One cam formation (27) may have a portion (27a) causing rapid lateral deflection of pin 25 when the slider reaches the second position such that the resistance provides "feel" to locate this position, which is held by pin 26 and cam (28). After being latched in the third position further pressure on button 21 releases pin 25 from cam (27) but the pin 26 is guided by a rib (33) to re-enter its cam (28) and retain the switch in its second position until button 21 is again depressed; thus the switch cannot be directly restored from the third position to the "off" position shown. In a modification (Fig. 4, not shown) a spring-loaded ball in slider 14 cooperates with a shoulder in body 11 to provide the "feel" for the second position.</p> |
