Patent GB-191417842-A (GB)
Title: Improvements in or relating to Sewing Machines.
Inventor: MEYER WILLIAM CRISTIAN
IPC: D05B15/00
Filed: 1914-07-28
Granted: 1915-09-28
Abstract: 17,842. Meyer, W. C. July 29, 1913, [Convention date]. Sewing-machines; chain-stitching by devices comprising barbed needle. The usual variable motion is given to the needle bar of a sewing- machine of the McKay type by means of a sliding connexion with a link supported at opposite ends by the pitmans of cranks having differing throws. A bifurcated lever-arm 47, Fig. 2, has pins 49 engaging in the slots on opposite sides of a block 48 secured to the head of the needle bar. The lever-arm 47 is integral with a bifurcated lever-arm 51, Fig. 5, carrying a pin between its branches, upon which a block 53 is mounted which slides in the slot in a link 54. The link 54 is supported at one end by a pair of pitmans 56 of a pair of similar cranks 58 and at the other end by a pitman 55 of another crank 57 between the cranks 58 and having a different throw. The slot in the link 54 is so shaped that the lower limit of the needle movement is fixed. The block 53 is coupled by a pair of links 58<1> to a lever 60 carrying an arcuate plate which is locked by means of two rollers and a cam-actuated wedge between them excepting when the presser first engages with the work in each cycle. The lever 60 has an arm 62 pressed by a spring 64 towards an arm 63 fast on a shaft 14, and the shaft 14 has an arm 13, Fig. 2, which enters a slot in the presser - bar. When the lever 60 is unlocked, the spring 64 brings the arm 62 up to the arm 63 and thereby positions in the block 53 in its slot in accordance with the thickness of the work. The presser-bar is pressed towards the work by a spring 9, Fig. 2, between a shoulder 5<a> on the bar and a screw sleeve 7. The downward limit of the presserbar movement is determined by a nut 10 on the presser-bar. The Specification as open to inspection under Section 91 (3) (a) comprises also the following matter:-The thread passes to the usual whirl by way of a wax pot and a tensioning device situated at the base of the horn. The thread passes round a thread wheel clamped between sleeves on a shaft which is retarded by means of a pair of brake shoes 107, 108, Fig. 19 (Cancelled), surrounding a disk 106 integral with one of the sleeves. The shoes are held from rotation by a pin 110 which engages a slotted part of the sleeve 108 and are pressed together by a spring 114. A pair of tongues comprising the levers 118, 119 is used to remove the brake shoes manually. The shank 73 of the cast-off slides between stops on a bar 74, which is given a stroke shorter than that of the needle-bar by means of a pin 76 on the needlebar which passes into a slot in the bar 74. The bar 74 is supported by a lever 81 integral with a pivoted disk 83 braked by contact with a spring-pressed non-rotary disk. Feed by presser-feet and the like.-The feedpoint receives a vertical work-engaging movement from a stationary cam as it moves through its lateral feeding stroke. It is disconnected from its operating-gear and withdrawn from the work as the machine is stopped. The trough-shaped carrier 86 for the feed-point 5 surrounds the horizontal part of a guide-plate 87 mounted to move vertically on the presserbar. The carrier 86 and the plate 87 are embraced by a slotted part of the presser-bar, and a pin 91 secured upon the carrier 86 passes through an horizontal slot in the central plate 87 and through cam-slots in the walls of the presser-bar slot. The feed-point and its carrier are given feeding movement by means of a link 93, and as they are moved to the left, the camslots cause them, together with the guide-plate 87, to move towards the work at first quickly to engage the work, and afterwards gradually, to keep the point in effective engagement with the work during the feed. On the return stroke, the carrier turns about the pin 91 as a pivot, so that the feed-point rides easily over the surface of the work. The lever 92 is linked to its cam lever 214, Fig. 16 (Cancelled), by a bar 213 which is coupled to the lever 214 by a bolt 219. During the stopping of the machine, a link 222 is moved to the left, draws the bolt 219 with it, and thereby frees the feed devices from their cam lever, and a spring moves them out of operative position. Presser-bars, lifting.-The presser-bin is lifted automatically through a distance independent of the thickness of the work by means of a lever 13, Fig. 2, on a shaft 14 which at its other end carries a lever 16, Fig. 5, and Fig. 9 (Cancelled). The lever 16 has a recess enclosing several discoidal leaves, between which are passed other segmental leaves 19 forming part of a cam-actuated lever 20. The leaves are normally pressed together by a spring 27 acting on a lever 24<a> pivoted at 25 to the lever 16 and thereby the lever 16 is locked to the camactuated lever. The lever 24<a> is periodically actuated, to release the lever 16 and permit the presser to adjust itself to the work, by means of a pin 28 adjustably secured to a cam lever. The boss 36 of the cam lever 20 is made of two screwed parts so that it can be lengthened to take up wear. The presser may also be lifted by the lever 16, a lever 37 engaging the underside of the lever 16 and a treadle gear including a lever and a treadle mounted universally so that it can be swung from engagement with the starting and stopping gear into engagement with another lever. Stopping-gear, automatic. - The machine is driven during stitching through a main clutch and a belt running on a pulley fixed on the machine shaft. In stopping, the main clutch is opened, the machine shaft is clutched to a lowspeed spiral gear 147 until the speed is reduced, and is then stopped positively by a device which also de-clutches the low-speed and puts on a brake. The machine is stopped just after the needle commences to descend, so that the needle loop is somewhat slack, and the presser-gear is unlocked. During the stopping operation, a special movement is imparted to take it out of contact with the work. The treadle used for controlling the main clutch is universally mounted so that it can be moved into position to operate either the presser lifting gear or the main clutch gear and a stop prevents its use in an intermediate position. A rod 133, Figs. 4 (Cancelled) and 12 (Cancelled), is associated with the main clutch gear, so that when the clutch is opened, a lever 184 is moved upwards. The movement of the lever 184 is inoperative until a shoulder upon it contacts with a trip lever 188 and removes this from a stop 189, whereupon a piece 186, Fig. 17 (Cancelled), upon which the levers 184, 188 are pivoted and to which a pin 177 is secured, moves upward and the point 176 of the pin 177 enters a recess in a lever 174, which normally swings idly under the influence of a cam-groove cut in the sleeve of one element of a low-speed clutch. When the lever 174 is locked by the point 176, the cam in its further rotation is caused by the lever 174 to move to the right, carrying with it the clutch element and thereby closing the clutch, which acts as a brake until the speed of the machine is sufficiently reduced, and then drives the machine at a low speed in a forward direction. The upward movement of the pin 177 releases a bar 202, which is pulled upward by a spring 211 so that a hook 203 upon it engages, near the end of the next revolution, a projection 204. The bar 202, which is pivoted upon a lever arm 206, is thereby carried to the left and a lever-arm engages with a rod 1.54, Fig. 14 (Cancelled), by which a clutch 153 is opened, disconnecting the low-speed gear drive, and a brake 156 is brought into action. If the speed of the machine when the parts 203, 204 contact is too great, the bar 202 is moved so far to the left that surfaces 211<b>, 211<c> contact and the bar is forced downward until the projection 204 is released and the machine permitted to make a further revolution. After the pin 177 is released by the trip-lever 188, it is held by a second catch-piece 190, Figs. 4 (Cancelled) and 17 (Cancelled), until the lever end 174 contacts with the catch-piece and moves it out of engagement with its stop. By this means, the pin 177 is released when the recess in the lever end 174 is positioned properly to receive the point 176. To put the positive stopping-gear out of action, the part 194 pivoted upon the catch-piece 190 is turned so as to remove it from the path of the lever end 174. This subject-matter does not appear in the Specification as accepted.