Patent GB-378921-A (GB)
Title: Improvements in duplicating machines
IPC: B41L9/04
Filed: 1931-04-17
Abstract: 378,921. Duplicating-machines. JOY, C. H., 457, North Racine Avenue, Chicago, U.S.A. April 17, 1931, No. 14971/32. Divided on 378,892. [Classes 100 (i) and 100 (ii).] Hectograph copying-apparatus.-In a duplicating-machine of the type in which a carriage provided with a platen roller is reciprocated over a bed for pressing, through the platen roller, a sheet of paper into contact with the duplicating-band, the platen roller being movable into and out of operative relation to the bed, an operating element for the carriage moves the platen roller in the carriage relatively to the bed and also, through the action on the platen roller, acts on a lock for the carriage to release the carriage when the platen roller is moved into operative position, this release taking place when the operating member has moved through a predetermined initial range of its entire path of movement. The gelatine or other duplicating- band or ribbon 4 is stretched over the bed 3 and guided over rollers 2. The carriage 5 comprises a heavy sheet-metal rectangular frame 6 which is open at the top and bottom. A transverse rockshaft 12 pivotally mounted in the carriage loosely supports arms 14 in the ends of which a platen roller 16 is rotatably mounted. The rock-shaft 12 is secured to an operating-handle 23 which facilitates the reciprocation of the carriage 5, and is adapted to actuate the rockshaft to raise or lower the platen roller. A rod 24, slidable in the handle 23 and normally held yieldably in raised position by a spring 25 engaging an enlarged head portion 26 of the rod, extends through the rock-shaft 12 and its lower end is bifurcated at 28 to embrace a stationary arcuate plate 29 fixed to the frame 6. The prongs of the bifurcations 28 are bridged by a transverse lug 30 which is engaged in a notch 31 in the arcuate plate 29 when the platen roller is in printing position. To raise the platen roller the head 26 is depressed to disengage the lug 30 from the notch 31 and the handle 23, together with the rock-shaft 12, rocked to swing the arms 14 and the platen roller upwardly. The carriage is not moved during this rocking movement until the lug 30 engages a stop 32 on the arcuate plate 29. When it is desired to remove the platen roller the rod 24 is depressed further against the action of an auxiliary spring 27 so that the lug 30 moves past and is retained by the stop 32. The lock for the carriage comprises a lever 74, pivoted on the frame 6 at 47, provided with a downwardly extending portion 75 at one end adapted to engage a notch 76 in the frame 1 of the machine when the carriage is at its terminal position, and with a projection 78 at the other end in a position to be engaged by the edge of one of the arms 14 of the platen roller. A spring 77 tends to depress the lever 74 in the locking position. When the platen roller is lowered to operative position the arm 14 swings the lever 74 about the pivot 47 and releases the lock, and on the withdrawal of the platen roller from operative position the end 75 of the lever 74 is lowered to engage the notch 76 when the carriage reaches its terminal position. The rock-shaft 12 is provided with arms 33 which move the arms 14 through the medium of springs 35 located in the arms 14 so that the platen roller may be kept in contact with the printing-surface regardless of irregularities on the latter. A stop-lug 34 for each arm 33 is also provided on each platen roller arm 14. Sheet-registering devices.-A rotary margin bar 40 for positioning and depositing a sheet of paper on the duplicating-band 4, is similar to that described in Specification 378,892, and is actuated by the operating-handle 23. Tripping-arrangements.-An automatic clutch 63, as described in Specification 378,892, is provided for engaging the roller in the raised position.