| 摘要 |
1,082,902. Press-button retractive switches. NAVIGATION COMPUTER CORPORATION. April 9, 1965 [May 22, 1964], No. 15202/65. Heading H2B. An electrical switch mechanism comprises a housing 10 and a key member 19 normally spring-biased to rest in one position and displaceable against the spring bias to actuate contacts 14, 15 and to engage resilient damping pads 32 to absorb the impact of the engagement at the end of the contact actuating movement of the key member 19 and to give the switch a soft bottoming characteristic to eliminate the feeling of an abrupt stop. Pads 32 may be of semi-rigid urethane. Member 19 slides in grooves 18 in housing 10 and nylon bumper 20 bears on the free end 16 of coil spring 15 so that when push 21 is depressed spring 15 is flexed and contacts fixed contact 14. The contact region of spring 15 is plated with precious metals such as rhodium. The antiresonant vibration node region of spring 15, when actuated by flexing end 16 is located at the position of fixed contact 14 to avoid bounce or chatter due to resonance of coil spring 15. The base of housing 10, through which terminals 12, 13 extend, has a slanted surface for permitting direct mounting on a flat printed circuit panel of a keyboard assembly.
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