Patent GB-455656-A (GB)
Title: Improvements in engraving machinery
IPC: B44B3/00
Filed: 1935-04-27
Abstract: 455,656. Milling-machines. TAYLOR, W., and KAPELLA, Ltd., 104, Stoughton Street, Leicester. April 27, 1935, Nos. 12627/35 and 11142/36. [Class 83 (iii)] [See also Groups XVI, XX, and XXIV] A pantographic engraving or like machine comprises a base, a carriage member for carrying and feeding the tool and constrained for movement relatively to the base in a plane, a primary reducing pantograph pivotally carried on a fixed axis on the base, pivotally constrained for movement in a plane parallel to the base and adapted to move the carriage in the plane and a secondary pantograph pivoted to the base and to the primary pantograph. The main axle, Figs. 1 and 2, of the pantograph, the pattern holder 5 and work holder 69 are all detachably and adjustably mounted by means of bolts in T-section grooves in a base 1, which may be mounted on the column 71 of a machine tool. A swivel member 11 is carried by spaced ball or roller bearings on the axle 8 and in its turn carries on an axle 12 and spaced bearings 13 a carriage 15 for the tool 19. To secure rigidity the bearings on the axles 8, 12 are each spaced further apart than the distance between the axles. The tracer arm 21 and link 26 are pivoted to the member 11 and carriage 15 and complete a parallelogram. The arm 21 may carry a tracer point or a pin 23 on a slider 88, which is mounted on the slidable link 87 of secondary pantograph. The bar 87 slides on arms 81, 82 pivoted to an arm 78, which is pivoted at 75 to a bracket 74 bolted to the base. The arm 82 carries a tracer 89. The axes of the axles and pivot pins 19, 8, 22 are always maintained in the same plane as are the axes of the pin 89, 22, 75. The ratio of the secondary pantograph can be varied by shifting the link 87 or reversed by interchanging the functions of the pivots 22, 89, 75, or, by bringing the link 78 to the other side of the pivot 22 the tool 19 can be caused to produce an upright copy of the pattern. The tool is driven by pulley 29, band 30 and a motor mounted on the member 11 with the axis of its pulley coincident with that of the axle 12. The tool 19 is mounted in a quill 17, Fig. 3, slidably coupled to the carriage 15 by crossheads 32, 36, moving against the pressure of springs 33 on rods 35, sliding in holes in lugs 37, 38 on the carriage. A rotatable tube 40 has a rim 41 engaging the bottom of a bore in the lug 37 and is itself engaged by a nose 47 on a head 46 at the bottom of a screw 45. A rotatable nut 43 on the screw 45 presses the cross-head 36 and tool downwards. For ordinary twodimensioned work the tool is adjusted by the nut 43, and the arm 21, which is flat and flexible, can be lifted from and replaced on the work. For three dimensioned work the arm is braced by a strut 65 and the tracer is formed as an adjustable screw, with a notched head co-operating with a spring detent. The nut 43 is similarly notched and provided with a detent in such a way that successive steps of the tracer and tool are proportional to the horizontal ratio of the pantograph. Successive layers at increasing depths are then removed by the tool. In an alternative method a former 49 is carried by an arm 48 mounted on the axle 8 and held in correct position by a wedge bolt 52 and a flat on the axle 8. A tongue 53 maintains the former in position on the arm 48. The former is followed by a follower 54 on the screw 45. To permit the reciprocation of the tool the tube 41 is turned until the nose 47 can slide in a keyway 42. A sleeve 57 with balls 56 acts as a frictionless guide for the extension 39 of the crosshead 36. Specification 6420 /94, [Class 101], is referred to.