Patent GB-556070-A (GB)
Title: Contouring machine and method
IPC: B23Q35/127
Filed: 1941-10-27
Abstract: 556,070. Selective punching machines. TRINKLE, D. R. Oct. 27, 1941, No. 13815. [Class 31 (ii)] [Also in Group XXII] A punched strip record for controlling a contouring or copying machine (see Group XXII) is made on a tracing machine in the following manner. An enlarged contour of the work to be reproduced is first made on a large scale and from this a line contour for the cutter path is obtained. Preferably this takes the form of a conducting line on a non-conducting sheet. The tracing unit for making a record for use with an end-mill where no rotational positioning is required includes a tracer point which can move in two perpendicular directions one movement being selected as the predominant and the other as the secondary movement. Step-by-step feed movements are imparted to the tracer in the predominant direction as long as the tracer point is on the pattern line but if the tracer moves off the line then one step movement in the secondary direction occurs. If this movement does not cause the tracer to contact the line the tracing stops and the predominant direction must be changed. The tracing machine comprises a unit 601 movable longitudinally on a carriage 602, Fig: 50, which itself moves transversely on a table 604 carrying the templet sheet 605. Pinions 609 on a shaft 611 engage racks on the table and have step-by-step movement to feed carriage and tracer transversely while another pinion engages a rack 622 to feed the tracer unit longitudinally under the guidance of rollers 623. The pinion for the longitudinal feed is mounted on a shaft 627 geared to a shaft 634 carrying oppositelyfacing ratchet-wheels 636, 637, associated with actuating pawls such as 638, Fig. 57, operated by a cam 647 on a cyclically driven shaft 648. The pawl is normally held away from its ratchet wheel by a latch 661 which is moved to pawlreleasing position by energizing a solenoid 664. Similar mechanism controls the opposite ratchet wheel. Each step of this feed moves the carriage .005 inch. Further similar mechanism geared to the pinion 611, Fig. 50, controls the transverse movement also in steps of .005 inch. Control dials 701-703 are provided for the predominant secondary and rotational controls respectively. The dials 701, 702, Fig. 74, actuate commutating devices to select the solenoids associated with the longitudinal and transverse feeds for obtaining any of the four directions of movement of the tracer head, the setting being indicated by arrows on the dial and the secondary feed being always perpendicular to the selected predominant feed. The tracer point 781 is mounted in a housing 758 connected by tubes 754 with the main housing and the tracer is connected by an insulated circuit to a terminal 798 where connections are made to solenoids as described below'. A secondary tracer point 807 urged by a spring 808 is mounted eccentrically in the tracer head beside the main point and is used when rotational adjustment recording is required. The lead from the main tracer point 781 extends to a solenoid 817 and from the secondary tracer to a solenoid 931, Fig. 74. When the solenoid 817 is engaged a rod 842 engages normally open contacts 848 and bell crank lever 844, Fig. 63, is drawn up. A cyclically operable shaft 648 carries a cam 886 which rocks a shaft 883 the full oscillation of which may be obstructed by latch mechanism 877, 882. During part of the cam movement the lever 844 is free to move if the solenoid 817 is energized, in which case a feed movement in the predominant direction is instituted, the contacts 848 being closed and a connection made to a point 892 on the predominant control dial 701. When the predominant circuit is interrupted because tracer point 781 does not complete the circuit of solenoid 817 the shaft 883 has an unrestricted oscillation, since the latch 877 no longer checks pawl 882 on the shaft 883, and a circuit is made by contacts 897 to the secondary control dial. If the secondary feed step does not restore the tracer point to the line being traced the tracing apparatus automatically stops because the pawl 882 pushes back the hook 873 to free the latch 877 which is moved into the path of the pawl on the next oscillation. The rotational tracing control mechanism includes opposed ratchet wheels operated by pawl mechanisms controlled by solenoids 919, 920. By selective actuation of these ratchet wheels in accordance with the setting of the rotational dial 703 the eccentric point 807 may be rotated by small chordal increments of about .005 inch in either direction. The rotational tracer 807 is associated with a solenoid 931 and contacts 943, Fig. 74, the solenoid being put out of operation if rotational control is not required. When the rotational tracer 807 is moved off the traced line and the main tracer is still on the line the tracer 807 is moved its incremental chordal distance. A predominant feed step can only occur if the rotational tracer is on the line. The various solenoids energized by directional and rotational controls have associated therewith the corresponding elements of mechanism for punching the record fed step-by-step through the machine. The record 373 travels over a die 977, Fig. 67, and sprocket wheel 966 and is wound on to reel 956. A shaft 652 at each revolution actuates pawl-and-ratchet gear for feeding the record one step if.a punching operation has occurred. Each punch 982 is pivoted to a link 1008, Figs. 67 and 71, engaged by an arm 1011 on a shaft 994 so that when any link is depressed shaft 994 is oscillated. Each link is connected to the normally retracted armature of a corresponding solenoid 1018, 1023, see also Fig. 74. Energization of these solenoids controls power mechanism for operating the punches. For this purpose a pair of arms 1032 carrying an actuating-comb 1031, Fig. 71, are 'actuated by cams 1038 on a cam shaft 1039 connected to driving sleeve 653. When any particular lirik 1008 is moved by its armature link 1016 against a spring 1024 the comb 1031 engages in a notch 1042 and reciprocates the corresponding punch. The punch selecting solenoids such as 1018 and 1021 are. controlled by circuit breakers. Fig. 74, so that each feed control solenoid of the tracer unit controls the corresponding punch-selecting solenoid. In a modification, a three-dimensional tracing unit is provided having one tracing unit 601A operating as described above and a depth tracer unit 1101 having a direction controlling dial 1102. The table carries the lay-out plate 605A. The depth unit includes solenoids 1103, 1104. connected by circuit-breaker contacts 1108, 1109. Fig. 77, to punching solenoids 1020, 1023, associated with the fifth and sixth columns of the record. Another dial 1114 enables the machine to be set for either three- or twodimensional tracing. The depth tracing is so controlled that as long as arm 844, Fig. 77, is in its outer position a feed step in the direction determined by the dial 1102 occurs but when the tracer point 1111 contacts a line, solenoid 1119 is energized and the arm 844 is latched up so that feed stops. Means is provided whereby the controls of the tracer point 1111 are connected to the contouring tracer point 781 whose usual controls are disconnected. The feed mechanism of the tracer 601A will then operate under line-stopping conditions, a setting which is used in, tracing and recording centre locations as described below. In Fig. 78, 1161 represents the outline of a piece to be contoured and 1162 the cutter centre path for profiling such piece. Hole centres are also marked at points 1163 . . . 1166, and at an external point 1167 to locate the cutter for starting the profiling. The hole centres are located by perpendicular but non-intersecting conducting lines such as 1168, 1169. The dial 1114 of the tracing apparatus is rotated to place the solenoid 1119 in control of tracing point 781 to obtain " line-stopping " operation. Control dial 1102 is set to give a downward feed The tracer is moved until tracer point 781 is adjacent the initial dot in the line and the hook 1121 released. The tracer then moves in increments of .005 inch at about 20-30 steps per second. The operative solenoid 687 closes circuit breaker 1050 so that punchselecting solenoid 1021 is operated to cause a perforation in the record for each step of movement which continues till line 1168 is reached and is then stopped by energization of solenoid 1119. The operator then changes the feed direction by setting the dial as at 1102B, releases the latch 1122 and feed occurs from 1168 to 1169 through solenoid 664 while solenoid 1022 correspondingly operates the punch in column four. When line 1169 is reached the unit stops thus locating the centre 1163. To restart tracing from this centre the operator holds out armature 844 until tracing point moves off line 1169 after which tracing continues to the line 1171 and then stops. At this point the dial 1102 is reset to change the feed direction and tracing resumed to reach point 1173 locating the centre 1164. When a centre point is reached the record is manually moved ahead several steps thus automatically stopping the machine for the actual drilling operation. Similar procedure is adopted for locating other points until point 1167 denoting the start of the actual contouring operation is reached. Specification 556,104, [Group XXII], is referred to.