Patent GB-1006298-A (GB)
Title: Improvements in and relating to machine tools
Inventor: HEPPELL DONALD ALBERT
IPC: B23Q16/00
Filed: 1962-10-01
Abstract: 1,006,298. Drilling machine details. MIDDLESEX TOOL & GAUGE CO. Ltd. Oct. 1, 1963 [Oct. 1, 1962], No. 37099/62. Heading B3C. A machine tool comprises a reciprocating quill which has a rapid forward and reverse trasverse, and a slow feed, a timer, and a control device, the latter including a collapsible abutment displaceable with the quill to reduce the forward traverse rate as the tool reaches the work, and simultaneously to actuate the timer which is set to a predetermined part of the machining time the abutment being progressively collapsed by an amount equal to the distance moved by the quill during the slow traverse, and means actuated by the timer at the end of the time interval to initiate the reverse traverse, the quill then moving during the rapid forward traverse past the point at which the slow rate was previously initiated due to the collapse of the abutment, to a point just short of that at which the reverse traverse was previously initiated, the abutment then causing the traverse to be reduced to the slow rate, the sequence being then repeated until the machining operation is completed. Spindle head s carries the quill and has a casting a secured thereto on which is formed a cylinder c, and a cylinder d slidable in cylinder c, is secured to a yoke 31 by a plate 29. A piston e in cylinder d has a rod f which is hollow at its outer end, and a plunger g having a rod h is mounted in the rod f and is urged away from the piston by a spring k. An adjustable bush i is screwed into rod f and a rod I projecting from plunger g extends through the bush and carries a flange q and a head m forming the abutment. A switch o is carried by a bracket p mounted on casting a and head m can pass through an opening r in the bracket to engage switch member n. Switch o is shown as switch LS4 in Fig. 1, T 1  is the timer, 16 is the motor which drives the quill, 78 is the rapid forward traverse actuator, 93 is the slow feed actuator and 97 is the rapid reverse actuator. In operation, a button 23 is pressed and actuator 78 is energized, thus supplying oil under the influence of compressed air to the quill, which is moved rapidly up to the work. Switch LS4 is closed and switch LS2 is changed over to de-energize actuator 78 and energize slow feed actuator 93 and also timer T1. A predetermined feed governed by the setting of timer T1 is carried out, whereupon actuator 97 is then energized to rapidly withdraw the quill. At the start of the operation cylinder d and piston e are fully extended in relation to cylinder c, the latter being filled with liquid and head m and flange q occupy the positions shown in Fig. 2. The quill is advanced until the timer is energized and piston e is forced into cylinder d an amount equal to the slow feed distance. At the end of the set time period, the movement of the quill is reversed and cylinder d carries piston e with it. During the initial part of the reverse, spring k urges elements g, h and I outwardly until plunger g engages bush i, whereupon elements g, h and I travel with the piston until switch LS2 is changed over. Head m is now clear of switch member n and opening r and the quill advances until head m operates switch LS4 to actuate the slow feed actuator. Head m is checked by bracket p, and spring k is compressed to move piston e further into cylinder d, thus, due to this movement of piston e into cylinder d, a pecking feed is provided. Specifications 1,001,864 and 1,001,865 are referred to.