Patent GB-816105-A (GB)
Title: A method of and machine for controlling the handling and working of workpieces
IPC: B23Q35/02
Filed: 1955-07-07
Abstract: 816,105. Programming for machine tools; drilling. COMPAGNIA ITALIANA FORME ACCIAIO. July 7, 1955 [July 7, 1954], No. 19707/55. Class 83 (3). [Also in Group XL (b)] Photo-electric means controlling operations, such as the drilling of holes in a prearranged pattern and sequence, on a workpiece, co-operate with a flexible inextensible opaque tape which has holes corresponding to the operations to be performed and is moved relative to the photo-electric head in correspondence with the movement of the work relative to the tools. As shown, a machine has a bed 1 supporting rails 2 on which runs a carriage 3 supporting the work. Drilling, reaming, and like tools are mounted in parallel relation on one or more gantries over the path of the work. The carriage 3 is provided with arms 8 which support the control tape 9 stretched along the front of the machine. The carriage is fed by two drive motors 23, 33 which cause relatively medium and low speed movement respectively. Operation of both together causes fast movement. Motor 23 rotates a nut 29 fixed relative to the carriage 3 and causes it to travel along screwed shaft 30. The shaft 30 may be rotated by motor 33 through gearing 35 and coupling 32. Each of the motors is provided with a magnetic brake 26, 36 which prevents movement of the rotor when the motor is not energized. The photo-electric head 20, Fig. 7, is attached to the front of the machine and has a slot 21 through which passes the control tape 9 above partition 50. The tape runs between guide rollers 51-54 and vertical rollers (not shown). Above the tape 9 are mounted two light sources 88, 91, the second of which is surrounded by an opaque cylinder 61. This cylinder is rotatable by a stepping relay and has a number of positions. In the initial position, a wide slot is located between the light and the tape, whilst in the " stepped-round " positions small holes are located in turn opposite each of the lengthwise tracks 72 to 76 (Fig. 12) along which control perforations may occur in the tape. The partition 50 is slotted at three positions 85-87; each slot extends across the whole width of the tape and central slot 86 is wider than the other two. Shielded photo-cells 89, 92, 93 receive light passing through the three slots respectively, and their electric outputs are amplified and fed to a control panel. A fan blows air down on the tape to clear the holes in it immediately before it enters the head 20. The exhaust air may be used to cool the electrical equipment in the head. Limit switches 39 cut out the motors when the carriage reaches either end of the machine bed 1. If the machine is loaded with work with the carriage at the left-hand end as shown, and switches operated to set both drive motors running to move the carriage to the right, the latter will continue at fast speed until the row of perforations on line 77 of the tape 9 reaches slit 85. Light passing to cell 89, when this occurs, causes the disconnection and braking of motor 23 so that the carriage is driven at slow speed until the same row of holes permits light to shine on cell 93, which gives an output stopping the drive completely. Cylinder 61 is now stepped round by manual or automatic means to locate in which position or positions there are holes in the tape 9. As each position on which light shines through a hole is reached, the required tool operation is initiated. When all the positions at which there may be perforations in the tape have been investigated by the stepping- round of cylinder 61, a wide slot again comes into position and the carriage movement is again started. The purpose of slot 86 and cell 92 is to prevent the carriage movement recommencing at high speed when another tape perforation is close to slot 87. If light is received by cell 92 at the recommencement of the drive, motor 23 is not energized and only slow-speeddrive occurs. Observing work.-In setting up the machine, the work is located on table 3 by an optical device on the machine frame, having a hair-line corresponding to the position of a tool and of a hole in the tape 9. This line is set opposite the required reference line on the work, which is then clamped to table 3.