| 摘要 |
<p>1,258,445. Mechanical switches; retractive switches; actuation of switches. PHILIPS ELECTRONIC & ASSOCIATED INDUSTRIES Ltd. 5 Feb., 1969 [8 Feb., 1968], No. 6170/69. Heading H1N. A push-button unit for tape recording and/or playback apparatus comprises a push-button movable to perform a control function, after that as the push-button is moved means produce a perceptible resistance to the movement, and after that the push-button is latched into the operative position. As shown, Fig. 1, when push rod 3 is pushed to the left slider 7 is moved to the left by spring 9 connecting push rod 3 and slider 7. Slider 7 grips switch operating members 6 by means of projections 8 and when slider 7 is moved to the left switch operating members 6 are moved operating contacts 5 in switch units 4. When projections 8 encounter the ends of slots 14 in frame 1 slider 7 cannot move any further to the left and if push rod 3 is released it moves back to the right under the action of spring 2. If push rod 3 is not relaesed but is moved further to the left spring 9 is tensioned thereby offering a perceptible resistance to movement. At the completion of the stroke extension 18 on push rod 3 snaps behind spring loaded catch 17 to hold it in position. If catch 17 is released manually, push rod 3 moves back to the right under the action of spring 2 carrying slider 7 with it. In use the push-button is intended to rewind a tape, for example, the push-rod being depressed until the perceptible resistance is reached and then released when the appropriate spot on the tape is reached, the push rod being latched in for long rewinds. In a second embodiment, Fig. 4, push rod 3 is pivoted and when the push-button is depressed actuates switch unit 4, the push rod then coming up against a brace 21 and spring 20 which provides a perceptible resistance to movement of the push rod, which eventually latches behind catch 17.</p> |
