GB930681A - Improvements in or relating to machine tools - Google Patents

Abstract

930,681. Lathe details. BIRFIELD ENGINEERING Ltd. July 30, 1959 [Aug. 1, 1958], No. 24809/58. Class 83 (3). A stop for a bar being fed through a collet in an automatic machine-tool, is movable axially and transversely, of the collet axis. The stop 2, Figs. 1, 2, is secured to a shaft 3, which is rotated to bring a spring-loaded pad 4 on the stop in line with the collet 1, and then swing away from the collet by a cam 10, which is synchronized with the mechanism for operating the collet, and actuates levers 5-7. The stop 2 is moved axially of the collet axis by a pneumatic cylinder 14. In operation, a bar 25, Fig. 3, is fed through the collet 1 by a second bar 26, until it compresses the spring 5 on the pad 4, and a workpiece is machined and parted off to the required length. This is repeated until the stub end of the bar reaches a certain point in the collet when a detecting means indicates that a new bar is required, and also actuates a control mechanism which supplies air to the pneumatic cylinder 14, Figs. 1, 2. The piston 16 turns a spindle 19, and levers 18, 21 counter-clockwise, thus moving the shaft 3 and stop 2 to the right, as seen in Figs. 1, 3. The stop 2 is rotated and ejects the stub end of the bar from the collet, and moves into line with the collet axis, thus locating the new bar 26 at a shorter feed position until the end of the bar is faced. Air is exhausted from cylinder 14 after a selected time due to a timing switch, and the stop is moved to its previous position. In a modification, stop 30, Figs. 7, 8, is moved from position A to the position B, thus indicating that a bar exists in collet 1. When the stop moves to position C, this indicates that there is no bar in the collet, and the operator is warned, or the machine is stopped. The stop is urged towards the collet by a spring 37 between a fixed stop 33 and an adjustable stop 34 on shaft 32. The rotational movement of the stop is as previously described. In a further modification, stop 41, Fig. 9, is rotated by a metal tape 43 wrapped around shaft 40, and secured to a fixed part 44 of the machine. As cross-slide 45 moves shaft 40 is rotated.