Patent GB-190611842-A (GB)
Title: Improvements in or relating to Machines for Folding Over a Portion of a Sheet of Flexible Material.
Inventor: LUFKIN RICHARD HENRY
Filed: 1906-05-21
Granted: 1907-05-21
Abstract: 11,842. Lufkin, R. H. May 21. Cutting - machines for leather &c. - Relates to machines for folding over the edges of a sheet of material such as leather, and consists principally in providing co-operating feeding and stretching members above and below the material, preferably of the four-motion feed type. The parts of the feed and stretching members, producing positive motion, are out of contact with the material during the return movement so that there is no retractile action tending to produce wrinkles. The invention is described in connexion with a machine of the type having a folding presser and also an edge gauge 10, Fig. 2, to guide the material under a knife 11, reciprocated vertically on a shaft 16, the knife coacting with a shearing block 12 that can be moved out of operation by a projecting lever. In this type of machine, the material is stretched immediately after a feeding-movement and simultaneously with the movements of the folder and knife. The knife is chiefly used to snip curved edges so as to enable them to be easily folded over against a bevelled block 14. The work is held down during the cutting operation by a presser foot 13, connected by a bar 23 with a vertical plunger 24. The turned-over edge is folded right down, so as to be stuck, if cemented, by a presser 15, actuated by a pivoted arm 25, which is connected outside the machine to an eccentric 27 on the power shaft. The feeding- mechanism consists of a composite frame having essentially an arm 29, Fig. 3, on which the upper .gripping-part A is mounted, and an arm 31 engaging loosely with a reciprocating part e, on which the lower gripping-part B is mounted. Both arms are joined by a connexion c to a vertically reciprocating rod d by which the part A is moved down on to the work before the feed, and away from it when feed has taken place. Lateral movement is obtained by rotating the parts 29, 31, c, bodily for a short distance round the rod d as a pivot. The rotation is effected by causing a pin z in a slotted extension 30 of arm 29, to enter a slot in an independent arm 20, which is pivoted below to the knife shaft and above is developed into a strap embracing an actuating eccentric. The part e, carrying the lower presser member B, has one end forked and entered by a fixed supporting roller 35. The fork admits of part e being moved lengthwise by the rotatable arm 31 which enters a vertical slot in a spindle g. The latter is supported so as to rotate, and takes a bearing below in the part e, and above in a recess in the part B. The lower presser member is moved to and from the work by a graduated cam f on which a finger 36 on the part e is held pressed by a spring 37. The cam is pivoted on au eccentrically-mounted spindle 40, Fig. 6, the arrangement bein such that by rotating the spindle by means of a cross-slot in its head the centre of rotation of the cam in the supporting frame is adjusted. A rod 41 connects the cam to a crank h on a shaft i which is rocked by an eccentric on the main shaft. At the end of the feed, the presser foot is dropped on to the work to hold it during the stretching operation. To ensure consecutive action of the pressar foot and feed-actuating bars 24, d, Fig. 2, respectively, both bars are pivoted above in slots in a cross-link 46, the end of which is pivoted to and derives motion from the upper end of knife shaft 16. A heavy leaf spring 47 presses down on the link at 48, and forces down on the work one of the bars 24, d, the depressed bar acting for the time as a fulcrum on which the link 46 lifts the other bar. The stretching-mechanism consists of upper and lower gripping-members C, D, Fig. 4, the lower one comprising a simple lever r, pivoted at 53, and oscillated in the arc of a circle by connecting- rod 54 from rock shaft i. The upper member receives a digging motion to and from the work to stretch it. It consists of a guide rod l, rigidly mounted on a bracket m, and telescoped into a tubular part k on which the head C is mounted. A helical spring tends to separate the parts k, l. The bracket m is adjustably held by a set-screw on an arm o which passes through a part p which is rotatable but otherwise fixed. The upper end of arm o is connected to an eccentric on the main shaft. The downward movement of member C under the influence of its spring is limited by a screw which is threaded into a lug on the part k, and which passes loosely through a hole in the bracket m, on which the screw head abuts.