Patent GB-855354-A (GB)
Title: Improvements in printing plate locking mechanism
IPC: B41F27/10
Filed: 1957-02-20
Abstract: 855,354. Printing surfaces. WOOD NEWSPAPER MACHINERY CORPORATION. Feb. 20, 1957 [May 28, 1956], No. 5744/57. Class 100 (2) A tension lock-up for printing plates compprises an axial series of hooks 42, Fig. 6, mounted on a shaft 2 for limited independent rotary movement with respect thereto, each hook being independently biased into engagement with notches 44 in the plate by springs 46 positioned in transverse bores in the cylinder and pressing against plungers 48 acting on the hooks. A poweroperated mechanism Figs. 2, 3 or a manually operated mechanism Fig. 10 is provided for rotating the shaft to release the hooks. The power-operated mechanism comprises a radially movable cam member 1 (Fig. 2) which effects oscillation of the shafts 2 carried by the plate cylinder 3 via linkages 5, 6 and 7. The member 1 is moved radially of the cylinder 3 by a link 9 attached to one arm of a bell crank lever 10 on the end of a shaft 11 of an oscillating piston mounted in a cylinder 12. The cam member 1 is held in either of its positions by a toggle mechanism 13, 14, 15. Rotation of the shaft 11 is effected by fluid pressure applied through one of the ports 18, 18a (Fig. 3) to one side of the cylinder 12. The pressure acts against vanes 16 on the shaft 11. Admission of pressure is controlled by a valve 19 having a port 36 for the admission of fluid under pressure to the valve, ports 37 connected to the ports 18, 18a, and spaced heads,38. The valve 19 is operated by a handle 27 pivoted at 23 and the weight of the valve piston is counterbalanced by a spring 22 mounted on a rod 25 which extends through a base in the machine frame and is adapted to project into a notch 29 in a collar formed on the shaft of the cylinder 3. The valve 19 cannot therefore,be operated to admit pressure to the port 18a to move the cam 1 to release the plates on the cylinder until the latter is in a predetermined position. The plate clamping hooks 42 are mounted with lost motion on splined shafts 40 (Fig. 6) connected to the shafts 2, spacers 43, Fig. 8 (not shown) being provided. Each hook 42 is individually biased by a spring 46, surrounding a rod 49, which bears on a member 48 which in turn bears on lugs 50 formed on the hooks 42. A screw 51 is provided for engaging a notch 52 in the member 48 so that the spring 46 may be inserted and held to the cylinder prior to the attachment of the clamping hook assembly thereto. Plate lifting fingers 45 are also provided for rotation with the shaft 40. Further hooks 52 are provided on a shaft 53 and are normally biased by springs 54 out of plate engaging position. The hooks 52 engage the opposite edge of a plate to that engaged by the hooks 42, and are adjusted circumferentially by inclined cam surfaces on bars 58 (Fig. 7) mounted for movement axially in slots in the cylinder 3. The bars 58 are provided with racks 60 engaged by pinions 61 on shafts provided with square ends for adjusting purposes. The plate locking mechanism is duplicated at each end of the cylinder and each end is provided with two sets of hooks 42, 52 at diametrically opposed points. The hooks 42 of one locking mechanism, where the cylinder carries eight plates, engage one edge of the two plates on one half of the circumference at one end of the cylinder and the hooks 52 of the same assembly engage one edge of the two plates on the other half of the circumference, two bars 58 being provided, one for the hooks 52 engaging the plate adjacent the end of the cylinder, and one for the hooks 52 engaging the plate adjacent the centre of the cylinder. The bars 58 are each provided with extensions 73 which project beyond the cylinder 3 and are supported in brackets 74, attached to the end portion of the cylinder and provided with scale markings. After adjustment the bars 58 are locked in position by screws. Each locking mechanism comprising one set of hooks 42 and one set of hooks 52 is mounted on a cover plate 55 which overlies a slot in the cylinder. The cover plates 55 are attached to the cylinder by a series of members 80 to which they are bolted. Bearing plates are provided for the ends 2 of the shafts 40 and the shaft of the rocker arm 5 which is acted on by the member 1. The toggle mechanism 13, 14, 15 is provided with a finger 90 which closes the switch 91 of the motor driving the cylinder when the cam 1 is moved to its outer position. In the manually-operated release mechanism, Fig. 10, the arm 5 is acted upon by a pivoted cam member 63 having cam surfaces 65, 66 and 67. The member 63 is operated by a crank 68 provided with a handle 69. By reason of the cam surfaces 65 and 66 the plate locking mechanism may be operated before the cylinder 3 has come to rest. Fixed cams 76 are also provided to act upon the rollers 4 of the arm 5 so as to ensure that the roller 4 is moved outwardly as the cylinder revolves should the springs prove ineffective. Radial pins 77 are provided on the cylinder to engage the end of an arm 78 projecting from the shaft of the crank 68 thus ensuring that the crank is turned to release the member 63 from plate releasing position. Specification 619,399 is referred to. Reference has been directed by the Comptroller to Specifications 682,819 and 688,566.