| 摘要 |
472,267. Engaging and disengaging toothed gearing ; variable-speed gearing. THOMAS, A. March 19, 1936, No. 8229. Convention date, March 19, 1935. [Classes 80 (i) and 80 (ii)] [Also in Groups XXXVI and XX] A control device for a variable condenser or like apparatus, giving a coarse and a fine adjustment and operated by an initial rotary movement imparted to a control member, comprises a rotatable and axially movable primary shaft associated with coarse adjustment means and fine adjustment means, one or other of which is retained under spring pressure in operative position by means of a leaf spring associated with and adapted to be flexed to one or other of two stable positions by axial displacement of the primary shaft. The shaft 7 of a variable condenser is adjusted by rotating a shaft 9 which is slidably supported in a plate 2 so that in the position shown a fine adjustment is obtained but when the shaft is pushed inwards a coarse adjustment can be made. The fine adjustment drive is obtained from the shaft 9 through two friction discs 10, 11 thereon, between which engages a friction disc 15 on a shaft 14. This shaft is freely rotatable in a sleeve 13 carried by a leaf spring 12 which is fixed to the shaft 9 and can occupy one of two positions, so that when the shaft 9 is moved inwards the spring snaps over from the position shown to its second position. In the position shown for obtaining fine adjustment a gear 16 on the shaft 14 is in mesh with a toothed wheel 8 which drives the shaft 7 through gearing but when the spring 12 occupies its second position, the shaft 14 swings angularly and moves the gear 16 out of engagement with the toothed wheel 8. The inward movement of the shaft 9, in addition to disengaging the members 8, 16, moves a friction plate 9<1> fixed to the end of the shaft 9 into engagement with the face of the wheel 8, and this forms a clutch in the drive for the rapid control. The spring 12 also prevents backlash. |
