Patent GB-191506748-A (GB)
Title: Improvements in or relating to Work Feed Mechanism for Sewing Machines.
Inventor: MEYER WILLIAM CHRISTIAN
IPC: D05B15/00
Filed: 1914-07-28
Granted: 1915-07-28
Abstract: 6748. Meyer, W. C. July 29, 1913, [Convention date]. Sewing-machines; feed by presser-feet; stopping- gear.-The feed-point receives a vertical workengaging 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 It is disconnected from its operating-gear and withdrawn from the work as the machine is stopped.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 presser-bar. 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 wall of the presser-! ar slot. The feed-point and its carrier are given feeding movements by means of a link 93, and as they are moved to the left, the cam-slots cause them, together with the guide-plate 87, to move toward 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. In the return stroke, the carrier turns about the pin 91 as a pivot, so that the feedpoint rides easily over the surface of the work. The lever 92 is linked to its cam-lever 214, Fig. 7, 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. The Specification as open to inspection under Section 91 (3) (a) comprises also the following subject-matter, which does not appear in the Specification as accepted :- Presser-bars, lifting automatically.-The presserbar is urged downward by a spring 9 abutting against a screwed sleeve 7, and its lowest position is determined by the contact of a nut 10 on the bar with the sleeve 7. By adjusting the sleeve, the lowest position is adjusted without varying the compression of the spring. By adjusting the nut, the lowest position and the compression of the spring are adjusted together. The presser-bar is lifted automatically through a distance independent of the thickness of the work by means of a lever 13 on a shaft 14, which at its other end carries a lever 16, Fig. 9 (cancelled). The lever 16 has a recess enclosing several discoidal friction leaves, between which are passed other segmental leaves 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 cam-actudted 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, 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 the lever. C7tain-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 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 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 arranged 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 carry ing an arcuate plate, which is locked by means of two rollers and a cam-actuated wedge between them, excepting when the pressure 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 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 the block 53 in its slot in accordance with the thickness of the work. The presser-bar is pressed toward the work by a spring 9 between a shoulder 5<a> on the bar and a screwed sleeve 7. The downward limit of the presser-bar movement is determined by a nut 10 on the presser-bar. 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 sur.ounding a disk 106 integral with one of the sleeves. The sleeves 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 are used to remove the brake shoes manually. The shank 73 of the castoff 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 needle-bar which passes into a slot in the bar 74. The bar 74 is supported by a lever 81 integral with a pivoted disk 83, which brakes by contact with a spring-pressed non- rotary disk. Stopping-gear.-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, and the machine shaft is clutched to a low-speed spiral gear 147 until the speed is reduced, and is then stopped positively by a device which also declutches the low-speed gear and puts on a brake. The machine is stopped just after the needle commences to descend, so that the neelle loop is somewhat slack, and the presser-gear is unlocked. During the stopping operation, a special movement is imparted to the feed-point 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 presserlif ing gear or the main clutch gear, and a stop prevents its use in an intermediate position. A rod 133, Figs. 4 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 the same 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 camgroove cut in the sleeve of one element of a lowspeed 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 154, 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 engage 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 catchpiece 190, Figs. 4 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 to joint 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.