Patent GB-249762-A (GB)
Title: Stencilling machine
IPC: B41L13/04
Filed: 1925-10-26
Abstract: 249,762. Inglesby, J. W. Oct. 26, 1925. Stencilling-apparatus. - A stencilling-machine of the type adapted to be used like a plane comprises a framework 1 on which are mounted drums 10, 28 carrying a stencil S stretched from one to the other, a rotating inking brush 54 arranged midway between the drums, an ink reservoir 50 carried by the brush, and means for releasing a predetermined amount of ink from the reservoir on to the brush. The mechanism is all covered in by a casing 7 removably secured to the framework 1. Initially, the stencil is coiled once around the drum 10 and, in use, it is unwound therefrom and on to the drum 28 the rotation of which tensions a coil spring 44 such that when the apparatus is lifted off the surface the drums and stencil are returned to their initial positions. Each drum has a recess 16 in which is arranged an eccentric shaft 17 adapted to clamp an end of the stencil against an arcuate plate 105 carrying a stop up to which the stencil is moved. In the release position of the shaft 17, discs 108 thereon form guides for positioning the stencil. To regulate the rotation of the drum 10, a retarding-device is provided consisting of a cam 20, Figs. 2 and 8, on the inner face of one end of the drum and a sleeve 23 slidably mounted on a stationary shaft 6 and spring-pressed towards the cam 20. Projecting from the sleeve 23 is a key 24 sliding in a wider keyway in the shaft 6. Initially, the key rests against a stop 21 on the high part of the cam, and, while the stencil is being unwound in use, the cam moves round until, near the ends of its rotation, the side 20<1> of the stop meets the key 24 which moves round in its keyway and gradually stops the drum. During the reverse rotation the friction between the key and the cam prevents too rapid rewinding of the stencil. A counter 101 is advanced at each forward rotation of the drum 10. Inking-apparatus. - The brush 54 is mounted on a hollow spindle 46 and is pressed down on to the stencil by a spring 58 ; it is rotated, during the operative stroke of the apparatus, by means of bevel gears 59, 87 driven by gearing from the drums 10, 28 through a ratchet clutch 89. The spindle 46 is screw-threaded internally to receive a hollow spindle 70 which is fixed to a cup 68 and forms at its lower end a valve 7 for controlling the flow of ink from the reservoir 50 to a chamber 51 communicating by apertures 55 with the brush 54. The cup 68 is provided with a screw cap 74 for filling purposes, the ink flowing down through the spindle 70 and then into the reservoir via apertures 73, and the air escaping through apertures 72. The valve 71 is opened by turning the cup 68, the extent of opening being determined by means of a spring pin which is fixed to the cup 68, bears against a knurled nut 65, and preferably abuts against a stop thereon. Ink can only flow, however, when air is admitted by depressing a plunger 79 part of which engages a conical seating in the cap 74. Air then passes into the interior of the plunger via apertures 83, 85 connected by longitudinal grooves on the exterior of the plunger and from there down through the spindle 70. The nut 65 is fixed to the spindle 46 and constitutes an adjustable stop for limiting the downward movement of the brush.