| 摘要 |
997,768. Crank linkages. A. F. SHIELDS. Dec. 31, 1963 [Jan. 7, 1963], No. 51384/63. Heading F2K. [Also in Division B6] In a mechanism in which there is a reciprocated element which is rapidly accelerated and decelerated during each cycle thereof, counterbalancing means is provided to minimize the stresses set up. The invention is described as applied to apparatus wherein sheets of cardboard &c. are separated from a stack 10 by a slide 33 mounted on a carriage 41 which is reciprocated along a bed 80. Two links 59 are pivoted to the carriage 41 and to arms 57 which are secured to a rock-shaft 50 rotatably mounted in the machine frame, and an arm 54 is secured to one end of the shaft 50 and is slotted at 53 to receive a roller 52 on a crank-pin 51 carried by a wheel 45. The wheel 45 is keyed to a stub-shaft 46 and has gear teeth 47 in mesh with a gear 81 driven at constant speed; thus, as the wheel 45 rotates the shaft 50 is rocked and the carriage 41 is reciprocated along the bed 80. The maximum velocity of the carriage 41 on the feeding stroke is equal to or slightly higher than the peripheral velocity of feed rollers 11, 11a for the sheets, and is higher than the maximum velocity of the carriage on its return stroke. The counterbalancing means comprises an arm 70, loosely pivoted on the rock-shaft 50, weighted at 79, and slotted to receive a roller on a crank-pin 75 carried by the wheel 45. Preferably, the pin 75 lags behind the pin 51 by 90 degrees to provide maximum counterbalance. The roller 11a is driven at constant speed by gearing from the gear 81, and the rollers 11, 11a grip the separated sheet when the carriage 41 has reached maximum speed. |
