US2753824A - Stop-motion controller for sewing machine clutches - Google Patents

Description

July 10, 1956 E.VO$SEN STOP-MOTION CONTROLLER FOR SEWING MACHINE CLUTCHES Filed June INVENTOR 0 WARD VGSSE/V wdp ATTORNEY United States Patent STOP-MOTION CONTROLLER FOR SEWING MACHINE CLUTCHES Edward Vossen, Lynbrook, N. Y., assignor to Stop- Motion Devices Corp., Brooklyn, N. Y.

Application June 1, 1953, Serial No. 358,821

3 Claims. (Cl. 112219) This invention relates to a stop-motion controller for sewing machine clutches.

Conventional sewing machines, particularly those used in industry, may be provided with stop-motion switches which are normally open when the machine is in operation and which close only when the thread breaks or terminates. These switches are connected to a stopmotion clutch control mechanism which disengages the clutch and thereby stops the machine when the switches close. The present invention relates to the stop-motion control mechanism to which the stop-notion switches are connected.

The principal object of this invention is the provision of a stop-motion clutch control mechanism which may be installed between the treadle and clutch of a conventional sewing machine without altering the sewing machine mechanism and structural parts and without requiring any change whatsoever in the mode of operation of the machine. Conventional sewing machines are provided with a rod which is connected to the clutch and with a second rod which is connected to the treadle, both rods being normally connected to each other so that working the treadle will actuate or control the clutch. In the present invention, the stop-motion clutch control mechanism is interposed between the clutch and treadle rods, the upper end of said mechanism being secured to the clutch rod. and the lower end of said mechanism being secured to the treadle rod. The machine is operated in conventional manner as though the stop-motion clutch control mechanism were not installed therein.

An important feature of the stop-motion clutch control mechanism herein claimed is its utter simplicity both in its principle of operation and in its structural parts. It is a fool-proof, positive action mechanism which operates without any attention on the part of the operator of the machine. It sets itself automatically and it operates automatically upon the closing of a stop-motion switch.

Another important feature of this invention is the normally closed safety switch which is built into the stopmotion clutch control mechanism herein claimed. When a thread breaks or terminates, one of stop-motion switches will close the circuit to said clutch control mechanism and said mechanism will thereupon disengage the clutch to stop the sewing machine. The circuit remains closed only momentarily-just long enough for the clutch control mechanism to operate-since the safety switch automatically opens with the operation of said clutch control mechanism. Thus, although one of the stop-motion switches may be closed by reason of the breaking or termination of one of the threads, the circuit to the clutch control mechanism will be open, following disengagement of the clutch, since the safety switch will now be open. When the broken or terminated thread is replaced, the stop-motion switch will be open and the safety switch may then be closed without closing the circuit to the clutch control mechanism.

There is another important feature which resides in 2,753,82 l Ice Patented July 10, 1

the ease with which the clutch control mechanism herein claimed may be installed in a conventional sewing machine. All that need be done is to disconnect the treadle rod from the clutch rod and then to secure the upper end of said mechanism to said clutch rod and the lower end of said mechanism to the treadle rod. Conventional treadle rods are provided with an adjustment feature which would compensate for the interposed length of the clutch control mechanism.

A preferred form of this invention is shown in the accomapnying drawing in which:

Fig. 1 is a front view of a stop-motion clutch control mechanism made in accordance with this invention, the front cover plate being removed from the housing of said mechanism to expose its working parts, said mechanism being shown in its normal operating condition which enables the operator to run the machine.

Fig. 2 is a similar view showing said mechanism in inoperative position, that is, following the breaking or termination of a thread and the stopping of the sewing machine.

Fig. 3 is a side view of said mechanism with the side wall of its housing broken away to expose its working parts, showing the mechanism in normal operating condition with none of the threads of the machine broken or terminated.

Fig. 4 is a view similar to that of Fig. 3 but showing the mechanism in inoperative position following the breaking or terminating of a thread.

The stop-motion clutch control mechanism 10 herein claimed has a casing 12 and a cover plate 14. The cover plate may be secured to the casing in any suitable manner and it will be noted that all of the working parts, save actuating rod 16 are mounted within said casing. Actuating rod 16 extends vertically through said casing and through bearing holes 18 and 20 formed in the top and bottom walls of said casing. It will be noted that the upper and lower ends of said actuating rod project outwardly from said casing and that said actuating rod is vertically movable both upwardly and downwardly through said bearing holes. A cross pin 22 extending through the outwardly projecting upper end of actuating rod 16 is engageable with the top wall of the casing to prevent downward movement of said rod relative to said casing beyond a predetermined point. A second stopmember is provided within the casing, as will hereinafter more clearly appear, to prevent upward movement of said actuating rod beyond a predetermined point.

The outwardly projecting downward end of the actuating rod is secured by conventional means to the treadle rod (not shown). An annular boss 24 is provided on the top wall of the casing to receive the lower end of clutch rod 26 and a set screw 28 is provided in said annular boss to engage said clutch rod and to lock it in place in said annular boss. This connection with the clutch rod and the aforementioned connection to the treadle rod are the only connections between the stopmotion clutch control mechanism herein claimed and the structural or operating parts of the sewing machine.

It will be seen from the foregoing that casing 12 moves integrally with clutch rod 26 and that actuating rod 16 moves integrally with the treadle rod. Since the clutch rod and the treadle rod in a conventional installation move integrally with each other, any relative movement that might take place between the casing 12 and the actuating rod 16 may be utilized for the stop-motion purposes of the present invention. When the casing and the actuating rod are locked against relative movement, their presence will not in any way whatsoever interfere with or modify the conventional operation of the machine. v The normal position of actuating rod 16 when the machine is in normal operation is its elevated position with its switch closing cam plate 30 in engagement with leaf spring contact member 32. When this is the case, said contact member is brought into engagement with a second leaf spring contact member 34. Contact 32 would nor mally be biased away from contact 34 and it is only when contact 32 is engaged by cam plate 30 that it is brought into engagement with the second contact member 34.

It will be noted that contact member 32 is secured to the inside wall of casing 12 by means of screws 36 and 38 respectively. It will similarly be noted that contact member 34 is secured to the same Wall by means of screws 40 and 42 respectively. Screws 36 and 40 serve as terminals or binding posts for the conductors which lead to the stop-motion switches and source of electric current. Screws 36 and 38 and screws 40 and 42 are all provided with insulating material in the manner shown in the drawing. Insulating washers 44 and 46 are provided to insulate screw 36 from contact member 32 and washer 44 and another washer 48 are provided to insulate said screw from the casing. Washers 50 and 52 are provided to insulate screw 38 from contact member 32. Insulating pad 54 and washer 56 are provided to insulate screw 40 from the casing and the same insulating pad 54 and washer are provided to insulate screw 42 from contact member 34. Screw 40 is not insulated from said contact member 34. It will be seen in the drawing that an electromagnet 60 is provided in casing 12 for a purpose which will shortly become apparent. There are two leads 62 and 64 which are connected to said electromagnet and it will be noted that lead 62 is connected to screw 36 and lead 64 is connected to contact member 32. It has been stated that screw 36 is insulated from said contact member. Consequently, when the two contact members 32 and 34 are brought together by cam plate 30, a circuit may be closed through screw 36, lead 62, electromagnet 60, lead 64, contact member 32, contact member 34, and screw 40. The circuit will, of course, not actually close until a stop-motion switch (not shown) closes upon the breaking or termination of a thread.

A bracket 70 is mounted within casing 12 and secured to the back wall 72 of said casing. This bracket supports all of the movable parts of the stop-motion mechanism herein claimed with the sole exception of actuating rod 16 and the contact member which it engages through its cam plate 30. Electromagnet 60 is secured to top flange 74 formed on said bracket 70 and it will be seen that said electromagnet may consist of two coils situated side by side and parallel, axially, to the longitudinal axis of actuating rod 16. A pivotally mounted armature 76 is situated opposite cores 78 and S0 of the electromagnet and it will be noted that it is supported by trunnions 82 and 84 which are journaled into side walls 86 and 88 of bracket 70. A leaf spring 90 is mounted on the armature between said armature and core 80 of the electromagnet and it will be understood that the action of this leaf spring is to push the armature away from the cores of the electromagnet. Conversely, when the electromagnet is energized, it attracts the armature against the action of said leaf spring.

Armature 76 is provided with an extension arm 92 which serves as a catch member with respect to an arm 94 which extends from an elongated hub 96. This hub is rotatably mounted on a rod 98 whose ends are secured to side wall 86 of bracket 70 and side wall 100 thereof. When the electromagnet is de-energized and armature 76 is thrust away from the cores of said electromagnet by leaf spring 90, it is in a position to engage arm 94 and to prevent it and the hub which supports it from pivoting about the axis of rod 98. It will be seen that another arm 102 is connected to hub 96 and the combination of said hub and arms 94 and 102 comprises a bell-crank.

A second bell-crank 104 is pivotally mounted on rod 106 Whose ends are secured to sides 86 and 88 of bracket 70. A torsion spring 108 is wound around said rod 106 and one end engages a boss on bracket 70 and the other end engages said bell-crank 104. Bell-crank 104 has one arm 110 which engages between arm 102 on hub 96 and a flange 112 on the same hub. When bell crank 104 is turned in one direction, its arm 110 pushes against arm 1'22 and when said bell-crank 104 is turned in the opposite direction, its arm 110 pushes against flange or projection 112. In the latter case, the movement of hub 96 is in the direction of bringing its arm 94 into engagement with armature 76. In the former case, the movement of hub would be in the opposite direction, namely, to a position where its arm 94 is out of engagement with armature 76 but this movement can take place only in the event that the armature is attracted by the electromagnet when the electromagnet is energized.

Beii-crank 104 has a second arm or catch 114 which is engageable with a notch 116 in actuating rod 16. The action of spring 108 on bell-crank 104 is in such direction that when the actuating rod 16 is moved upwardly until arm 114 enters notch 116, said arm 114 will assist in moving the actuating arm upwardly to its uppermost po sition. Arm 114 also serves as a stop member to prevent upward movement of said actuating rod 16 above its said uppermost position. This is possible because arm 110 of bell-crank 104 engages flange 112 on hub 96 at such time as the actuating rod reaches its topmost position. Further pivotal movement of bell-crank 104 in the same direction is thereby prevented and arm 114 looks the actuating rod 116 against any further upward movement.

Actuating rod 116 is locked against downward movement because bell-crank 104 is itself prevented from pivoting in the opposite direction from the direction last mentioned. This is because arm 110 of bell-crank 104 is in engagement with arm 102 on hub 96 and arm 102 is itself locked against pivotal movement by reason of the fact that arm 94 to which it is connected is engaged by armature 76 and more particularly extension piece 92 on said armature. When the electromagnet is energized, it attracts the armature out of engagement with arm 94. This frees arm 102 for pivotal movement in the direction necessary to release arm 110 of bell-crank 104. The bell-crank is now free to pivot in the direction necessary to release actuating rod 16 for downward movement. Downward movement of said rod will cease upon engagement of cross pin 22 with the top of casing 12.

In the operation of a typical sewing machine in which the stopmotion mechanism herein claimed is installed, the following sequence of events takes place in connection with the functioning of said stop-motion mechanism: The operator of the machine pivots or rocks the treadle in such direction that the treadle rod moves upwardly, taking actuating rod 16 along with it. When the actuating rod reaches its uppermost position, bell-crank 104 will engage notch 116 in said actuating rod and the bell-crank will pivot sufficiently to swing arm 94 into engagement with the armature. The actuating rod will now be locked against any movement relative to the casing of the mechanism. Since the clutch rod is secured to the casing and since the treadle rod is secured to the actuating rod, the clutch and treadle rods will now be locked against any relative movement and the treadle rod may be used to actuate the clutch rod in conventional manner.

The treadle may now be pivoted or rocked so as to pull down upon the treadle rod, the stop-motion mechanism herein claimed, and the clutch rod and the machine will now operate. When a thread breaks or terminates and a stop-motion switch (not shown) is thereby caused or enabled to close, the circuit to the electromagnet in the claimed mechanism and the source of electric current (not shown) will be closed and the electromagnet energized. The armature will now be attracted by the electromagnet and it will disengage arm 94, thereby freeing said arm for pivotal movement and thereby also freeing bell-crank 104 for pivotal movement. The pressure of the operators feet upon the treadle will tend to pull actuating rod 16 downwardly. The clutch spring (not shown) will tend to pull casing 12 upwardly and by reason of these two opposing forces, actuating rod 16 will be moved downwardly through the casing until cross pin 22 will prevent any further such movement. Cam plate 34 now disengages contact member 32 which springs out of engagement with contact member 34, thereby opening the circuit and de-energizing the electromagnet.

The stop-motion switch (not shown) is now closed by reason of the breaking or termination of the thread. When the broken or terminated thread is replaced or rethreaded in conventional manner, the stop-motion switch will be reset, either manually or automatically, to open position. The treadle may once again be pivoted to thrust the actuating rod 16 upwardly until it is locked against movement relative to casing 12. Cam plate 30 will thereby be brought into engagement with contact member 32 to cam said contact member into engagement with contact member 34. The electromagnet will not be energized because of the open condition of the stopmotion switch. The procedure above described may now be repeated in order to operate the machine.

The foregoing is illustrative of a preferred form of this invention and it will be clearly understood that this preferred form is subject to modification and that other forms are contemplated within the broad spirit of the invention and the broad scope of the claims.

I claim:

1. A stop motion controller for a sewing machine comprising a clutch rod and a treadle rod, a casing, an actuating rod mounted on said casing for movement relative thereto, means adapted to attach said casing to the clutch rod of a sewing machine of the character described, means adapted to attach said actuating rod to the treadle rod of said sewing machine, a catch in said casing which is engageable with the actuating rod to prevent relative movement between said actuating rod and said casing and thereby to prevent relative movement between the clutch and treadle rods, a locking mechanism, including an armature, mounted in said casing for engagement with said catch to lock the catch in engagement with the actuating rod, and an electromagnet mounted in said casing in operative position relative to said armature, whereby the armature is attracted by the electromagnet when said electromagnet is energized to unlock the locking mechanism with respect to the catch and thereby to release the catch from the actuating rod, said catch comprising a first bell-crank, the actuating rod having a notch formed therein for engagement with one of the arms of said first bell-crank, the second arm of said bell-crank being in engagement with the locking mechanism, said locking mechanism comprising a second bellcrank having one arm which is engageable with the armature when the electromagnet is de-energized, said second bell-crank having a second arm which is engageable with the second arm of the first bell-crank on one side thereof, the second bell-crank having a projecting portion which is engageable with the second arm of the first bell-crank on the opposite side thereof.

2. A stop motion controller for a sewing machine comprising a clutch rod and a treadle rod, a casing, an actuating rod mounted in said casing for movement relative thereto, means adapted to attach said casing to the clutch rod of a sewing machine of the character described, means adapted to attach said actuating rod to the treadle rod of said sewing machine, a catch in said casing which is engageable with the actuating rod to prevent relative movement between said actuating rod and said casing and thereby to prevent relative movement between the clutch rod and treadle rod of the sewing machine, a locking mechanism, including an armature, mounted in said casing for engagement with said catch to lock the catch in engagement with the actuating rod, and an electromagnet mounted in said casing in operative position relative to said armature, whereby the armature is attracted by the electromagnet, when said electromagnet is energized, to unlock the locking mechanism with respect to the catch and thereby to release the catch from the actuating rod, said catch comprising a first bell-crank, the actuating rod having notch formed therein for engagement with one of the arms of said first bell-crank, the second arm of said bellcrank being in engagement with the locking mechanism, said locking mechanism comprising a second bell-crank having one arm which is engageable with the armature in locking engagement therewith when the electromagnet is deenergized, said second bell-crank having a second arm and a projecting portion formed adjacent said second arm in spaced relation thereto, said second bell-crank being engageable with the first bell-crank by receiving the second arm of the first bell-crank between said second arm andprojecting portion of the second bell-crank, whereby said second bell-crank serves as a keeper for the second arm of the first bell-crank to hold the first bell-crank in engagernent with the actuating rod when said second bellcrank is itself held by the armature when the electromagnet is de-energized, said second bell-crank being movable to move the first bell-crank out of engagement with the actuating rod when the electromagnet is energized and the armature is thereby caused to disengage said second bell-crank, said second bell-crank being also movable in the opposite direction for re-engagement with said armature when the electro-magnet is de-energized and to reengage the first bell-crank with the actuating rod.

3. A stop motion controller in accordance with claim 2, wherein the catch .is spring-urged for movement out of engagement with the actuating rod, being held in engagement therewith against said spring action by said locking mechanism when the locking mechanism is in engagement with the armature and the electromagnet is de-energized, whereby energization of the electromagnet attracts the armature out of engagement wtih the locking mechanism and frees said locking mechanism for movement under the influence of the spring action of the catch, thereby permitting the catch to disengage the actuating rod, movement of the locking mechanism in the opposite direction being adapted to cause said catch to move into engagement with the actuating in opposition to its spring action.

References Cited in the file of this patent UNITED STATES PATENTS 1,727,013 Johnson et a1. Sept. 30, 1929: 1,995,763 Basil et a1 Mar. 26, 1935 2,350,397 Haas June 6, 1944 2,418,356 Kleber Apr. 1, 1947

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