US2509600A - Rotary take-up for sewing machines - Google Patents

Description

May 30, 1950 Filed July 27, 1948 R. E. J'QHNSON ROTARY TAKE-UP FOR 4SEWING MCI'IINES 3 Sheets-Sheet 1 May 30,` 1950 R, E, JQHNSQN 2,509,600

ROTARY TAKE-UP FOR SEWING MACHINES Filed July 27, 194s s sheets-sheet 2 May 30, 1950 R. E. JOHNSON 2,509,600

ROTARY TAKE-UP FOR SEWING MACHINES Filed July 27, 1948 3 Sheets-Sheet 3 Patented May 30, 1950 ROTARY TAKE-UP FOR SEWING MACHINES Ralph E. Johnson, Rahway, N. J., assignor to The Singer Manufacturing Company, Elizabeth, N. J., a corporation of New Jersey Application July 27, 1948, Serial No. 40,865

6 Claims.

This invention relates to a needle-thread takeup device for sewing machines, and more particularly to a rotary take-up for lock-stitch sewing machines.

A consequence of the use of rotary motion in the take-up or thread-controlling mechanism of a sewing machine is the probable occurrence of thread-winding in instances such as when the thread breaks and the end portion leading from the supply becomes snubbed or bound upon a rapidly revolving, thread-engaging element of the take-up.

A feature of this invention, therefore, is the development of a means for preventing threadwinding in rotary take-ups which is both effective in its operation and economical to produce. A further advantage of the new device is its adaptability to a single-rotary take-up, particularly one in which the thread-engaging element is cycled in a non-circular orbit.

The accompanying drawings show a preferred embodiment of the invention, in which,

Fig. 1 is a longitudinal vertical sectional view of a single needle, lock-stitch sewing machine containing the new take-up mechanism.

Fig. 2 is a head-end elevation of the sewing machine head and includes a full face view of the take-up.

Fig. 3 is a full face View of the take-up with a portion of the cover-plate broken away to reveal the movable, thread-engaging pin and the stationary thread-breaking pin.

Fig. 4 is a full face View of the take-up with the cover-plate completely removed and showing the rotatable, thread-engaging pin in a position subsequent to that shown in Fig. 2.

Fig. 5 is a perspective view of the cover-plate of the take-up showing the hinged element upon which the stationary thread-breaking pin is mounted.

The sewing machine in which the new takeup has been shown is of the conventional, singleneedle, lock-stitch type, having a bed portion l supporting an upright standard 2 which carries an overhanging bracket-arm 3. The bracketarm, which is provided at its free end with an enlarged hollow-'head portion 4, houses a rotary arm-shaft 5 externally actuated through a beltdriven balance wheel 6. A needle bar l, slidably mounted in the head portion is reciprocated by the arm-shaft 5 through a crank 8 and connecting link 9.

The arm-shaft also carries a feed-lift eccentric ID and an adjustable, feed-advance eccentric II which convey the usual four-motor.

2 work-feeding movements to a feed-dog I2 through a pair of pitman links I3 and I4 and through a feed-advance rock-shaft I5 and a feed-lift rock-shaft (not shown) A rotary hook I6 is secured to the end of a rotary hook-shaft I'I journaled in the bed portion I and is driven from the arm-shaft 5 through a vertically disposed connecting shaft I8.

The take-up device comprises a single, movable, thread-engaging element I9 which is cycled in a mono-cusped, epitrochoidal orbit about the center of rotation of a rotary take-up shaft 20 which actuates the take-up. The take-up shaft 20 is driven from the arm-shaft 5 by means of a pair of gears 2| having a 1:1 speed ratio.

The epitrochoidal motion of the thread-engaging pin I9 is achieved by means of sun and planet motion in which a sun gear 22 is rigidly mounted to the frame of the sewing machine concentrically with respect to the take-up shaft 20 which extends therethrough. A large disk 23 is centrally mounted on the free end of the takeup shaft l2l) and a small disk 24 having a hub-portion 25 is rotatably journaled in the large disk 23 eccentrically thereof. A planet gear 26 is secured to the hub 25 adjacent the inside face of the disk 23. The planet gear 26 meshes with the sun gear 22 and is caused to roll about the periphery thereof as the disk 23 is rotated by the take-up shaft 20. The small disk 24 is thus caused to revolve about the center of rotation of the take-up shaft 20, as Well as to rotate about its own center. The thread-engaging pin I 9 is mounted on the small disk 24 eccentrically thereof and hence partakes simultaneously of two revolutionary movements about spaced centers, resulting in its passing through a mono-cusped, epitrochoidal orbit I9 (Fig. 4) once for each stitch-forming cycle. For a detailed description of such a take-up motion, reference may be had to the U. S. patent application of D. A. Graesser, Serial No. 26,525, led May 12, 1948.

This invention is primarily concerned with a means for preventing winding of the needlethread upon the revolving, thread-engaging element. Without an anti-winding device it is possible, if the needle-thread should break, for a rotary take-up to wind upon its thread-engaging pin an extraordinarily large mass of thread in the brief interval it takes an operator to perceive the mal-function and stop the Inachine.

This anti-winding device comprises a stationary thread-breaking pin 21 the free end of which is received in a concentrically disposed channel 28 in the large disk 23 during a portion of the take-up cycle, and in an interconnecting horseshoe channel 29 in the small disk Ell for the remainder of the cycle. The stationary thread-breaking pin 2l is supported by a takeup guard-plate 3l] which is provided with a door 3l hinged thereto on an inclined axis 32. A latching detent 33 holds the door closed and maintains the stationary thread-breaking pin in its proper position relatively to the moving channels 28 and 29.

The annular, concentric channel 2t in the large disk 23 accommodates the stationary thread-breaking pin 2l for that portion of the cycle in which the large disk 23 is rotating past the stationary pin. The horseshoe channel 2B in the small disk 2d receives the pin for that portion of the cycle in which the small disk is being carried past the pin. In Fig. 4 the stationary pin is shown as it is passing from the channel 28 into the channel 29. In Fig. 2 the pin 2l is disposed in the center of the horseshoe channel 29, and in. Fig. 3 it is passing from the channel 29 and reentering channel 23. The revolving thread-engaging pin at this point passes closer to the thread-breaking pin than at any other time in the take-up cycle, and in fact, momentarily yields control oi the thread to the stationary thread-breaking pin over which the thread then lies (Fig. 2.) rlihis represents the point at which the take-up gives up the maximum amount of thread to the needle and hook. In this interval the moving -thread-engaging pin I9 has circumscribed the stationary pin 2l. Ii, during the operation or the machine, the thread leading from the supply has at a previous point in the cycle become snubbed on the revolving thread-engaging pin i9, which condition precedes winding, it will be looped under the stationary pin 2l as the moving pin le describes its orbit thereabout. As the moving pin then moves upwardly away from the stationary pin the looped thread will be stressed, and the stress will increase with each cycle of the take-up until thread-breakage occurs, terminating the winding action.

It should be noted that because the free end of the thread-breaking pin projects into the channels 28 and 29, thereby extending inwardly beyond the root of the thread-engaging member, the possibility of the thread escaping off the end of the thread-breaking pin is practically precluded and its effective operation insured.

The broken piece of thread, if fouled on the pin 21, may then be removed by swinging open the hinged door 3i, thereby carrying the breaking pin from its operative position to an exposed position facilitating the removal of the broken piece of thread. Because the door :il is hinged on an inclined axis 32 it will, when released` tend to fall open, and will, furthermore, remain open until closed by the operator.

Having thus set forth the nature of the invention, what I claim herein is:

l. In a sewing machine, a rotary needle-thread take-up device including a thread-engaging member, driving mechanism for revolving said thread-engaging member in a mono-cusped epitrochoidal orbit at non-uniform angular velocities about a fixed center, a stationary threadbreaking element operative to prevent abnormal winding of the needle-thread on the threadengaging member, and a carrier for positioning said thread-breaking element at a radial distance from the fixed center of revolution of the thread-engaging member greater than the minimum radius of revolution attained by said threadengaging member and less than the maximum radius of revolution attained thereby.

2. In a sewing machine, a rotary needle-thread take-up device including a thread-engaging member, driving mechanism for revolving said thread-engaging member in a mono-cusped epitrochoidal orbit at non-uniform angular velocities about a Xed center, a stationary threadbreaking element operative to prevent abnormal winding of the needle-thread on the thread-engaging member, and a carrier for positioning said thread-breaking element within the orbital path traced by said revolving thread-engaging member at a radial distance from the xed center of revolution thereof which is substantially equal to the minimum radius of revolution of the thread-engaging member plus one half of the distance between the minimum and maximum radii of revolution of the thread-engaging member.

3. In a lock-stitch sewing machine having a reciprocatory needle and a rotary hook, a rotary take-up device including a thread-engaging member, driving mechanism for revolving said thread-engaging member in a mono-cusped epitrochoidal orbit, a stationary thread-breaking element operative to prevent abnormal winding of the needle-thread on t'he thread-engaging member, and a carrier for positioning said threadbreaking element within the orbit of travel of said thread-engaging member, said thread-breaking element being disposed closest to the revolving f thread-engaging member substantially at the point in the take-up cycle at which the take-up gives up the maximum amount of thread to the said needle and hook.

4. In a lock-stitch sewing machine having a reciprocatory thread-carrying needle and a rotary hook, in combination, a rotary needle-thread take-up including a thread-engaging member, driving mechanism for revolving said threadengaging member in a mono-cusped epitrochoidal orbit, a stationary thread-'breaking pin for preventing abnormal winding of the needle-thread about the thread-engaging member, and a carrier for positioning said thread-breaking member substantially along a straight line joining the thread-engaging member and the needle at that point in the take-up cycle at which'the take-up gives up the maximum amount of thread to the said needle and hook.

5. In a sewing machine, a rotary needle-thread take-up device including a primary rotary element having a nat face and adapted to rotate about an axis substantially .perpendicular to said face, a secondary rotary element mounted in said primary element eccentrically thereof and having a flat face substantially coplanar with respect to that of the primary element, means for rotating said primary element, means for concurrently rotating said secondary element about an axis parallel to that of the primary element, said secondary element thereby partaking of combination revolutionary and rotary movement, a thread-engaging element carried by said secondary rotary element eccentrically or the center of rotation thereof, a stationary thread-breaking pin for preventing abnormal winding of the thread on the thread-engaging element, said thread-breaking pin being disposed to project into the orbit of travel of the thread-engaging element, said primary rotary element being provided with a curvilinear channel to accommodate the free end of said thread-breaking prin as the primary element rotates relative thereto, and said secondary rotary element being provided with a curvilinear channel interconnecting with that in the primary element and adapted to accommodate the thread-breaking pin as the secondary element rotates and revolves relative to the thread-breaking pin.

6. In a sewing machine, a rotary needle-thread take-up including a primary disk adapted to roftate about a fixed axis normal thereto, a substantially coplanar secondary disk rotatably mounted in the face of the primary disk eccentrica-ily thereof and adapted to rotate about its own axis concurrently with the rotation of said primary disk, said secondary disk thereby partaking of combination rotary and revolutionary movement, a thread-engaging pin carried by said secondary disk eccentrically thereof, a stationary thread-breaking pin disposed substantially normal to the plane containing said disks and within the orbit of travel of said thread-engaging pin,

6 said lprimary disk being provided with an arcuate concentric channel for accommodating said thread-breaking pin as the primary disk is rotated relative thereto. and said secondary disk being provided with a curvilinear channel for accommodating said thread-breaking pin as the secondary disk is revolved and rotated relative thereto.

RALPH E. JOHNSON.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 2,358,493 Graesser Sept. 19, 1944 FOREIGN PATENTS Number Country Date 219,158 Germany Feb. 23, 1910

Images