Patent GB-962160-A (GB)
Title: Improvements in or relating to machines suitable for operating along marginal portions of workpieces
IPC: A43D43/02
Filed: 1960-07-18
Abstract: 962,160. Folding edges of non-metallic sheet material. BRITISH UNITED SHOE MACHINERY CO. Ltd. July 18, 1960 [July 17, 1959], No. 24901/60. Heading B5K. [Also in Division G3] A machine for operating along marginal portions of workpieces, e.g. for folding over an edge, comprises a work support, a tool, and means for co-operating with the support and engageable with the workpiece for causing marginal portions of the latter progressively to be presented to the tool, said means including an edge gauge provided by an abutment adjacent to the tool and arranged to be engaged by a marginal portion of the workpiece, a pair of movable work control members, differently spaced inwardly of the edge of the workpiece, for exerting a feeding action on the workpiece and urging it against the abutment as it is fed, and means for driving one of the control members in either of two directions with variable speed according to the curvature of a marginal portion of the workpiece approaching the tool while driving the other control member in the corresponding direction with a speed proportionate to that of said other control member to effect steering of the workpiece. The machine illustrated is for forming a folding operation on marginal portions of workpieces and includes a hammer 10 co-operating with an anvil 12 and provided with suitable actuating mechanism substantially as disclosed in the Specification 544,010. Preferably, the machine includes adhesive feeding means 26 (Fig. 7) as disclosed in Specification 749,892 for applying adhesive to the workpiece in the vicinity of the operation of the hammer and the anvil. The machine has a frame comprising a base 14 and an overlapping arm 16. To the base 14 is attached a removable supporting plate 20 across which a workpiece W, e.g. a flexible sheet material such as leather, is to be automatically guided for edge folding. An edge gauge comprising a turning post 22 is located adjacent the hammer and anvil and has an upturned surface for deflecting the scarf S (Fig. 7) upwardly prior to the application of adhesive and to the tapping down by the hammer. For the automatic guiding of a workpiece W about a substantially fixed point P (Fig. 5), a pair of movable work control members in the form of coaxially mounted wheel 28, 30 are provided. These wheels are mounted for reversible intermittent and independent rotation on a common shaft 32 under the control of means responsive to changes in curvature of the marginal portion of the workpiece. Shaft 32 is supported for heightwise movements and is preferably inclined slightly to the horizontal plate 20, and to the plane X (Fig. 5) normal to the direction of feed of the workpiece. The control wheels may also exert a feeding action on the workpiece which supplements that of the hammer and anvil and this action is obtained through various parts of the gearing shown, from the central shaft 48 which is driven from a main motor which also controls the operation of the hammer and anvil in a cyclic manner. In operation, during the first half of a cycle, the wheels 28, 30 are driven through pinions 50, 54, 56 and 58 and the associated gear trains from the main motor via an intermittently acting clutch to supplement the straight line feeding imparted to the workpiece by hammer 10 and anvil 12. Following the feeding step, when the workpiece has been released from the hammer and anvil, the wheels 28, 30 operate to turn or steer the workpiece. For this purpose the wheels 28 and 30 are driven through the same train of gears but now driven solely by a pinion 70 which is connected to the shaft of a servomotor 34, to rotate the gear 66 in one direction or the other according to the sign of the error voltage resulting from a light beam passing the edge of the workpiece and directed through aperture 128 from bulb 120 to register on photo-electric cell 130. When driven by pinion 70 the gear train acts as an epicyclic and the two wheels 28 and 30 are driven at different peripheral speeds, but always in the same proportion, such that their nett effect is to turn the workpiece about the centre P until the error voltage is reduced to zero, i.e. when the edge of the workpiece has been restored to cover aperture 128. The machine includes in its controls, means 156 (Fig. 9) for adjusting the zero error voltage position so that the position of the edge of the workpiece relative to the post 22 may be varied, thus determining the width of fold effected by the hammer and anvil. Further the controls include a relay K3 energized by amplifier 152 in response to partial interruption of the light path to the cell 130. The relay K3 closes contact K3-A, whereby assuming closure of master switch 132, an adhesive supply control solenoid 158 is energized to close switch 160 and open switch 162, and open the control valve in the adhesive supply line. Resultant energization of solenoid 116 initiates automatic feed and guidance of the workpiece. Simultaneously a relay K2 is energized which closes contact K2-B of a holding circuit for solenoid 116 and closes a normally open contact K2-A which, when switch 162 is closed, starts timer T and energizes relay K1. After the workpiece passes through the machine, cell 130 automatically de-energizes relay K3 to effect out-feed of the workpiece from the machine. Specification 910,746 is referred to.