| 摘要 |
<p>783,297. Stopping shafts in predetermined positions. UNITED KINGDOM ATOMIC ENERGY AUTHORITY. Feb. 2, 1956 [Feb. 8, 1955], No. 3708/55. Class 80 (2). A shaft 18, which operates a valve for taking samples of liquids from a number of pipes, for testing, is adapted to be stopped in any one of fifty-four positions by a primary shaft 16, driven by a motor-driven shaft 10 through a lost-motion claw-coupling 17 and driving the positioned shaft 18 through a non-slip reducing- gear 20. The primary shaft 16 is capable of arrest in either of two positions spaced 180 degrees apart, corresponding to the set positions of the shaft 18, by a detent comprising two axially or radially spring-pressed rollers 30 engageable in V-notches in a fixed plate 25, or cylinder, and the lost-motion coupling 17 permits the detent springs to advance the shafts 16, 18 ahead of the driving-shaft 10 as the located position is approached. During such advance, one of contacts 39 on the positioned shaft 18 makes a contact 40 which may energize a position indicator, or operate a timer which switches off the driving motor and applies a magnetic brake thereto, for a predetermined time, after which the cycle is repeated. The motor may, alternatively, be continuously rotated, and the spring detent may be replaced by one with co-operating fixed and rotatable magnetic teeth.</p> |
