Patent GB-1349350-A (GB)
Title: Guiding apparatus for a sewing machine
IPC: D05B33/00
Filed: 1970-06-18
Abstract: 1349350 Sewing NATIONAL RESEARCH DEVELOPMENT CORP 15 June 1971 [18 June 1970] 29640/70 Heading D1G An article is guided past a sewing machine 11 by apparatus comprising supports 25, 27, 29, 31 for the article, the machine 11 being disposed between two of the supports 25, 27, and sensor means 59 being provided to produce a guidance signal indicative of the position of the edge of the article to be stitched relative to a desired position, means 35 being provided to move at least one support (25) to guide the edge to that position. As described the work is of tubular form and the edge is either folded and blind stitched (Figs. 1-3 not shown) or an elasticated tape is to be sewn thereto. In the former case edge folding mechanism 37 is provided. Sewing tubular articles, fluidic sensors. The rolls 25, 27, 29, 31 are rotatable in bearings 33; the roll 27 is mounted on the rod of a pneumatic run 36 controlled by a solenoid value SV2 to be moved transversely of the roll axis to allow the article to be mounted on the roll. Roll 25 is movable parallel to its axis, to guide the edge being sewn, by the pneumatic ram 35 having an air suspended piston controlled by pneumatic relays SUR1 and 2. The sensor 59 is a fluidic sensor, as is a further sensor 67 which detects the approach of the seamed edge.  Seams, folding edges, severing work. The completed edge presents a folded edge (1 Figs. 1-3 not shown) secured by a blind stitch (7); this is accomplished by folding the edge to an S shape (Fig. 6 stitching through the fold 15 and trimming off the free end 17 by a reciprocating knife 21<SP>1</SP>, Fig. 4, not shown) and allowing the folded bight to fall back. The folding device (Fig. 6) comprises a first element 41 with a first tongue 43, a second element 39 hinged at 57 and presenting a second tongue 49 and a third element 201 presenting a third tongue 202. The first element is pivoted at 203 to the third element so as to be deflected against the action of spring 205 when the starting point of the sewn seam of the tubular article returns and abuts the tongue 43, thus operating microswitch MS2 to operate a valve SV6 controlling a pneumatic ram 53 and withdraw the elements 41, 201 from the path of the sewn edge. A hook 208, and a rod 209 is moved by a run 211 to remove the edge of the article from the sewing machine. At the commencement of sewing the element 39 is swung down into position where it operates a monitoring microswitch MS1. Operation. The Specification described circuitry which may be actuated by the fluidic sensors or by photo-electric devices to control the seaming in the manner described after the operator has started the machine and then switch off the guidance effected by the rollers 25, 31 when sensor 67 detects the seamed edge; operation of switch MS2 starts timers to operate the hook 208 when the stitching is completed with a slight overlap, and to stop the machine after operation of hook 208. Finally the operator lifts the second element 39 of the folding device, when operation of switch MS1 causes the roller 27 to move to the loading position and the rollers 31 and 35 to move to a 'parked' position controlled by a further sensor 212. In modifications a wheel (441, Figs. 14b, c not shown) is provided to uncurl the edge of the work and the folding guide is modified (Fig. 13 not shown) to eliminate the tongue 202.