Patent GB-728289-A (GB)
Title: Improvements relating to the pressing and automatic punching-out of portions from non-metallic sheet material
IPC: B26F1/00
Filed: 1951-12-19
Abstract: 728,289. Cutting-out presses. COULTHARD, J. Dec. 15, 1952 [Dec. 19, 1951; July 23, 1952], Nos. 29699/51 and 18569/52. Class 31 (1). [Also in Groups XXIV and XXX] In a cutting-out press in which a slab of fibrous or other non-metallic material is intermittently fed beneath a continuously reciprocating press tool and is punched whilst supported by one of a plurality of spaced rigid plates circulated by a conveyer, the latter is allowed to advance only when the press tool has completed a definite proportion of its return stroke and thereafter to remain in motion during the working stroke of the tool until such time as the advance of a conveyer plate into appropriate relation with the tool is determined by a feeler mechanism influenced by the plates. In the form shown, the press, which is for cutting-out filter and other pads from slabs of cotton wool and the like, comprises a row of tools 28 carried by a platen 20 which is reciprocated by means of a pair of connecting rods 21 associated with a crankshaft 22 driven from a main shaft 26. The conveyer 14 carries a series of plates 16 of nitro-cellulosic material and passes around upper and lower pairs of sprockets 46, 50. One of the lower pairs of sprockets is mounted on a shaft 52 which is driven through a friction clutch 70 from a shaft 53 continuously driven from the main shaft 26. The clutch comprises a driving member in the form of an inflatable hollow elastic ring 60, Fig. 2, secured to the shaft 53 and provided internally with friction pads 61 adapted, when the ring 60 is inflated, to be applied to a drum 62 freely rotatable on the shaft 53 and in driving engagement with the shaft 52. The ring 60 is inflated by means of compressed air admitted through a valve 68 actuated by a solenoid 69. The drum 62 is adapted to be held stationary by means of a brake 77 operated by the solenoid 69, the circuit being completed through adjustable switches 79, 80. The switch 79 is of oneway type and is adapted to be momentarily closed during the initial part of the return stroke of the platen 20 by means of a pivoted catch member 81 engaging a trip lever 82. The switch 80 has a two-way action and comprises stationary contacts 80a, 80b, Fig. 3, and a movable contact 80c controlled by a spring- urged feeler lever 83 which, when the medial line of one of the plates 16 is directly below the row of tools 28, projects through a gap between adjacent plates 16. When the circuit through the clutch 70, solenoid 69 and the normallyclosed contacts 80a, 80c is momentarily completed by the closure of the switch 79 under the influence of the rising platen 20, the brake 77 is released and the drum 62 is free to rotate on engagement of the clutch 70. The next successive plate 16 will depress the feeler lever 83 so as to open the contacts 80a, 80c whilst closing the normally-open contacts 80c, 80b. Subsequently, although the continued upward movement of the platen 20 allows the switch 79 to open, the circuit is maintained through the contacts 80c, 80b, and the conveyer advances until the next gap between plates 16 arrives above the feeler lever 83 and allows the latter to rise and the switch 80 to revert to its original condition. Since the switch 79 is now open, the separation of the contacts 80c, 80b causes the brake 77 to be re-applied and the clutch 70 to be released with the result that the conveyer stops in readiness for the next descent of the tools 28. Each incoming slab fed by means of a conveyer S is compressed and has any internal stress produced during its formation removed therefrom by being engaged successively between a roller 8 and each of a number of rollers 7, the roller 8 being driven from one of the upper pairs of sprocket wheels 46 by means of an endless chain 48 passing around sprocket wheels. Each slab is kept flat during entry of the tools 28 by means of a pad 30. The punched slab is transferred to a series of rollers 33 and the punched portions of the slab are ejected into a shoot 44 by means of plates 42 which move downwardly with the press tools. The perforated waste material passes on between a pair of rollers 45. Specification 701,327 is referred to. According to the first Provisional Specification, a continuously-driven sun wheel meshes with a plurality of angularly-spaced planet pinions rotatably mounted upon a carrier disc or spider frictionally located e.g. between spring-loaded clutch plates at one end of a sleeve which carries the lower pair of conveyer driving sprockets. The sleeve is capable of being held stationary by means of an electrically- or electromagnetically-operated brake associated therewith, a similar brake being associated with a sun sprocket journalled upon the sleeve and connected by an endless chain to planet sprockets on the shafts of the planet pinions. The two brakes are energized alternately by simultaneous actuation or release of two switches controlled by a spring-loaded rocking lever one arm of which is connected to a guided feeler which is urged upwardly by the spring towards the path of the conveyer plates except at such times as it is positively retracted by means of a solenoid acting upon the other arm of the lever. The solenoid is adapted to be energized by the closure of a pair of switch contacts mounted on the press platen and on a stationary part respectively. The punched slab is transferred from the endless conveyer to a subsidiary endless conveyer which leaves the severed portion unsupported so that the punched portions of the slab can be ejected. The subsidiary conveyer comprises a plurality of endless tapes which embrace the main conveyer and rest in recesses formed in its constituent plates, the tapes being circulated by the movement of the main conveyer but being diverted around idle rollers at one end of the main conveyer.