US3031987A - Thread break safety device for shoe machines with automatic welt severing mechanisms - Google Patents

Description

R. W. BRADLEY ETAL May 1, 1962 3,031,987 THREAD BREAK SAFETY DEVICE FOR SHOE MACHINES WITH AUTOMATIC WELT SEVERING MECHANISMS Filed March 15, 1960 3 Sheets-Sheet 1 [loyd G Mzller Robert WBrad/ey By theirAztarrzey EEC l @WM MIH Q May 1, 1962 R. w. BRADLEY ETAL 031,987

3 THREAD BREAK SAFETY DEVICE FOR SHOE MACHINES WITf-I AUTOMATIC WELT SEVERING MECHANISMS Filed March 15, 1960 3 Sheets-Sheet 3 II; II

United States Patent Ofiice 3,031,987 Patented May 1, 1962 Jersey Filed Mar. 15, 1960, Ser. No. 15,186 15 Claims. (Cl. 112-46) The present invention relates to Goodyear inseam sewing machines for attaching welts to lasted shoe uppers and sole members, in which a welt is severed automatically in advance of the sewing point in the machine through the use of a feeler engaging the leading end of the welt first attached to the shoe as that end approaches the operating point a second time during continued sewing operations. More particularly the invention relates to improvements in slack or broken thread safety devices arranged to prevent severing of the welt in case the machine is of necessity stopped to correct slack or broken thread before the completion of a seam extending about a shoe, as disclosed in an application for United States Letters Patent, Serial No. 840,148, filed September 15, 1959, upon application of the present inventors.

In the inseam sewing machine of the prior application above identified, a welt is severed automatically at a position in advance of the sewing point, either through the use of a feeler for engaging the end of the welt first attached to the shoe or, in the alternative, through the action of a stopping mechanism in bringing the machine to rest at the end of a seam. When the machine is used in either manner to effect the welt severing action, difficulty is encountered if it is necessary to bring the machine to rest before the end of the seam is reached, as for instance, upon the occurrence of a break in the thread or other improper sewing operation. In the machine of the prior application a thread break safety device is provided which renders the welt severing mechanism inoperative in that machine to sever the welt. The thread break safety device of that machine operates on the occurrence of slack thread at that particular time in each stitch forming cycle of operation in which each stitch of a seam is being tightened and set. That thread break safety device requires the use of a slack thread measuring means, including a thread tension responsive lever which is locked at certain times during each sewing cycle and unlocked at other times when each stitch is being set. Necessarily, the prior thread break safety device is somewhat complex in its construction, is subject to possible malfunctioning under certain conditions, and is difficultto adjust for the best results.

To avoid the difiiculties encountered with the use of the prior thread break safety device, it is an object of the present invention to provide an improved device for this same purpose, which will be simpler in construction, freer from the likelihood of malfunctioning, and more easily adjusted than the prior device. A further object of the invention is to provide a safety device for use in a Goodyear welt inseam sewing machine in which the welt is severed automatically at the end of a scam, the safety device having its principle of operation based upon the movement of thread past a thread tension device rather than upon actual occurrence of slack thread.

To achieve the objects noted, the present machine has, besides the usual stitch forming, feeding and guiding devices, an intermittently acting stitch setting device, a welt severing knife actuated by mechanism including a solenoid and an armature connected to the knife, a current supply line, and a normally inoperative circuit controlled in advance of the time for stopping the machine to connect the solenoid with the supply line, the machine also being provided with a time delay circuit acting after the stitch setting device tightens a stitch with a predetermined tension in each sewing cycle to render a normally inoperative safety circuit operative temporarily for that period only of time required to tighten a succeeding stitch. Thus, the inoperative circuit controlled in stopping the machine may be rendered operative only in case each stitch formed during a previous stitch forming cycle is adequately tightened against the action of a tension device, and there is no possibility that the welt may be severed after an operator discovers a broken thread or other improper stitch formation, while the safety circuit is operative. Accordingly, the welt will not be severed as a result of an emergency stop before the scam in a shoe is complete. In this way an unnecessary joint in the welt along an intermediate portion of the inseam is avoided and other difiiculties normally encountered in making such joint are obviated. In the illustrated form of this feature the thread tension device consists of a conventional traction member or wheel, against which the stitch setting device acts in setting each stitch and the means for initiating the period of time delay includes an electrical switch actuated by the traction member whenever the traction member is shifted by the thread. As illustrated, the time delay is accomplished by use of a relay having a coil connected to a condenser, and contacts in the switch provide a path of retarded discharge through the coil to render the circuit for the knife actuating solenoid operative during that period of time required for the condenser to become discharged. With such arrangement the period of time delay may readily be adjusted by the use of a variable resistor connected to the relay coil.

While the present invention is to be described in connection with a Goodyear welt inseam sewing machine and is utilized for the purpose of rendering a welt severing knife mechanism inoperative to sever the welt whenever improper operation of the stitch forming devices occurs, the invention is not intended to be so limited but is capable of advantageous use in any type of sewing machine in which an auxiliary operation is performed and in which it is desired that such operationbe avoided when improper stitch formation occurs. Accordingly, it is within the scope of the present invention to utilize the normally inoperative safety circuit disclosed herein for such purposes, including the bringing to rest of the machine automatically and independently of the normal control of the machine exercised by the operator and other equivalent auxiliary operations.

These and other features of the invention as hereinafter described and claimed will readily be apparent to those skilled in the art from the following detailed specification, taken in connection with the accompanying drawings, in which:

FIG. 1 is a perspective view looking from the left front of a sewing head in a machine embodying the features of the present invention;

FIG. 2 is a plan view on an enlarged scale of the machine head shown in FIG. 1;

FIG. 3 is a sectional detail view in front elevation and on a further enlarged scale of portions of a thread break safety control switch mechanism in the machine; and

FIG. 4 is a diagram of circuits employed.

The machine illustrated in the drawings is a Goodyear welt shoe inseam sewing machine, such as that disclosed in the application above identified, and is provided with the usual stitch forming, setting, work feeding and guiding devices for the shoe parts. The stitch forming, setting, feeding and guiding devices are capable of operating entirely around the marginal portions of a last supported Goodyear welt shoe upper and sole member, and at the end of an inseam inserted by the machine the welt is severed by aknife mounted for movement toward and from the welt as it passes through its guiding devices, automatic mechanism being provided for actuating the knife including an electromagnetic solenoid, an armature connected to the knife and a feeler of extremely light weight and sensitivity mounted for engagement by the leading end of the welt already attached to the shoe, as that end approaches the stitch forming devices a second time.

Referring to FIGS. 1 and 2 of the drawings, the parts of a shoe including an insole 2, an upper 4, mounted on a last 6 and a welt 8 are operated upon by stitch forming and setting and work feeding devices of the machine which inserts an inseam 14 and the leading end of the welt 8 first attached to the shoe is engaged by the feeler, indicated at 12 (see FIG. 4) and mounted for movement toward and from a position of engagement with the leading welt end during the feeding movement of the shoe, as that welt end approaches the point of sewing operations a second time. As the leading welt end engages the feeler a control circuit is closed and the welt severing knife, indicated at 14, is projected'against the welt along that portion engaging a welt guide '16 to form a bevel cut at a position in advance of the point of operation of the stitch forming devices. Thereafter, the machine continues in operation until one or more stitches are inserted overlapping the ends of the welt, which ends are thus brought into, close fitting abutting relation with each other. The machine is brought to rest as the inseam is being completed by driving and stopping mechanisms under the control of an operator and other mechanisms are thrown into operation for advancing the end of the welt remaining in the machineacross the sewing point in preparation for the start of an inseam in a new shoe.

The welt severing knife 14 is rigidly secured to an armature 18 of a solenoid Ztl (FIG. 4.). The solenoid 29 is connected to the control circuit having main alternating currentsuppy lines 22 and 24. in order to avoid the possibility that the feeler 12 may be actuated by improper engagement of the shoe during the major portion of. an inseam an operator actuated microswitch 26 is provided to prepare a normally inoperative safety circuit connected to the solenoid to be energized a few stitches in advance of the end of the inseam 10 connecting the shoe parts. Closure of the safety circuit renders a feeler actuated switch 28 capable of initiating the welt severing operation. In the machine of the prior application a similar normally inoperative safety circuit is rendered.

operative to connect the welt severing solenoid with a source of power by engagement of the operator's knee with a pad corresponding to the pad 30carried by a lever 32 fulcrumed on a portion of the machine frame 34. Except for the removal of an isolation transformer in the diagram of FIG. 4 and for the changes to be described the illustrated machine is the same as that of the application.

In the machine of the present invention the normally inoperative circuit cannot be rendered operative by the closure of contacts in the safety microswitch 26 alone, the normally inoperative circuit being arranged to be rendered operative only as a temporary expedient so long as the stitches inserted by the stitch forming devices are properly tightened. To this end the present normally inoperative safety circuit is connected with a time delay circuit acting for a limited time after the stitch setting device tightens each stitch in the work. Although it is sufiicient to render the safety circuit operative for a period of time required to tighten the next succeeding stitch only, as a practical matter it has been found effective if the period of time during which the safety circuit is operative is extended for two or possibly three stitches. This is because it is extremely unlikely that an operator can bring to rest a machine of the type to which the present invention relates within two or possibly three stitches after he d discovers that the thread has become broken or the stitches are being tightened with improper tension.

The control circuit for the knife actuating solenoid 20 includes the supply line 24 at one side of the solenoid, and at the other side of the solenoid a set of normally closed contacts KZB of a releasing relay, a set of normally open contacts K313 of a knife actuating relay K3, a selector switch 154, a set of safety relay contacts KlC and a secondary line switch LS1, all as described more fully with the use of the same reference characters in the prior application. above referred to.

The normally inoperative safety circuit includes the coil of the knife actuating relay K3, which. when energized closes the contact K313 and causes the knife actuating solenoid to be connected to the supply lines. The coil of the knife actuating relay K3 is connected at one side directly to the supply line 24 and at the other side to a resistor R3, the feeler switch 28, a contact SS, of a selector switch including an element 144 engaging the contact SS, a set of contacts KlB of a safety relay K1, a set of contacts KSA of a time delay relay K5, a rectifier 144), a resistor R2 and the selector. switch 154, back to the other side of the supply linc22, as in the case of the solenoid control circuit. The rectifier acts to supply direct. current for the knife actuatingrelay K3, thus enabling a more nearly. instantaneous actuation of the knife actuating relay after the. feeler switch 28 is closed.

The time delay circuit includes the coil of relay K5,

the energization of which is dependent uponmovement of the thread past a tension device. As the thread is drawn past the thread tension device a serrated pole.

piece of a magnetic disk 36 rotates past a switch provided with an actuating plate 38 of high magnetic permeability, mechanically connected to a contact in the.

switch for actuating the switch intermittently. The switch plate 38 is actuated by the magnetic disk first, in one direction and then, the other as the disk is rotated. Intermittent movement of the plate 33 in one direction completes an electrical connection betweenthe rectifier 149 to a two microfarad condenser 40, charging the condenser during the first stitch of a new seam, and thereafter, movement of the plate -38 in the other direction causes the charge of the condenser 40 to be transferred to a second two microfarad condenser 42. As soon as the second condenser 42 is charged it startsvto discharge through the coil of relay K5, energizing the relay and closing the contacts KSA. Closing the contacts KSA renders the normally inoperative circuit between the feeler switch 28 and the knife actuating relay K3 to be prepared for operation, so that as the knee lever 32 is actuated by the operator, closing the switch 26 and.

actuating the safety relay K1, the safety circuit will be rendered operative. thread or if a stitch is set with improper tension for more than two stitches after the knee lever 32 is actuated, the condenser 4-2 will become completely discharged through the coil of the relay K5, causing the contacts KSA to be opened. Opening the contacts KSA renders the safety and solenoid circuits inoperative.

When the machine is at rest it is occasionally desirable to cause the welt severing knife 14 to be actuated for test purposes or to form a bevel cut at the leading end of a welt newly introduced into the machine. Accordingly, the machine is equipped with an auxiliary manual push button 43 connecting the selector switch 154 through the coil of a relay K6 to the supply line 24. For convenience in actuation the push button 43 is mounted to project from a connection box 44 at the left side of the machine. The relay K6 is provided with a set of contacts K6B connected in parallel with the contacts KlB and KSA, in such position that closure of thecontacts K613 will complete the circuit to the knife actuating relay K3, even though the machine has been If there is a break in the sewing brought to rest and no thread has been drawn past the tension device within the specified time limit of the delay circuit. To insure a reliable actuation of the knife actuating relay upon closure of the push button switch the coil of the relay K6 also has a set of contacts K6A bridging the manual push button switch 43. Besides actuation of the manual button 4.3 it is also necessary to hold the treadle 94 depressed, at least partially, to close a switch LS2 and to comply with other requirements for energizing the control circuit for the solenoid 20. The push button switch 43, thus renders the safety circuit operative independently of the time delay circuit.

Besides the welt guide 16 the stitch forming, stitch setting and work feeding devices of the machine include a needle 45 (see FIG. 1) of the usual curved hook type, a looper 46, a thread finger 48, a take-up 50, a thread tension wheel 52 (FIG. 2) comprising a traction member over which the sewing thread, indicated at 54, passes. The stitch forming devices are actuated by a main sewing shaft 55 (FIG. 1) having at its left end a hand wheel 56. Others of the stitch forming, setting, feeding and guiding devices are more fully described in the prior application. As the take-up 50 acts to tension the thread and to set each stitch in the work, a predetermined tension is applied to the thread and the tension wheel 52 is rotated to provide additional thread for use in a succeeding stitch. The tension wheel is secured to one end of a shaft 57 rotatably mounted in a bracket 58 secured to the machine frame. The shaft 57 is surrounded by a tension wheel brake in the form of a spring 60 for imparting frictional resistance to the tension wheel and for insuring that the tension applied to the thread will reach a predetermined value while each stitch is being set.

The magnetic disk 36 is secured by a screw 62 to the other end of the tension wheel shaft 57 and the bracket 58 has fastened to it a brace 64 carrying a clip 66 within which is mounted an insulating tube 68. Within the tube 68 is disposed the permeable plate 38. Also within the tube 68 are mounted four contacts 70, 72, 74 and 76, of which contacts 70 and 74 are connected together with a single lead-in wire '78 and the other contacts 72 and 76 are connected with individual lead-in wires 80 and 82 (see also FIG. 3). All of the contacts are sealed within the upper end of a giass bulb 84 contained within the tube 68. At the lower end of the bulb 84 is sealed a lead-in rod 86 carrying a leaf spring 88, to which the permeable plate 38 is attached for causing the upper end of the plate to be yieldingly pressed normally into a position bridging the contacts 70 and 72 and which together with the plate 33 provide the means for initiating the period of time delay for the normally inoperative safety circuit. The disk 36 is located with its magnetic field passing through the plate 38, so that as the disk rotates opposite serrations will come into line with the plate and actuate it away from the contacts 70 and 72 and against the contacts 74 and 76, which provide means for charging the condenser 40. The movements of the plate are reversed as the spaces between adjacent serrations come into line with it. By utilizing the magnetically operated switch formed by the time delay initiating contacts and the condenser charging contacts 70 and 76 to charge first condenser 40 and thereafter to initiate transfer of the charge to condenser 42, there is no possibility of connecting the condenser 42 directly with the power lines. Thus, the safety circuit is rendered operative so long as proper sewing continues.

To adjust the period of time required for the condenser 42 to become discharged, in accordance with the preference of the operator for rendering the safety circuit operative for either two or three sewing cycles, in which improper tension is applied to the sewing thread, the coil of the relay K5 is connected in series with a variable potentiometer 90 (FIG. 4) through which the charge on the condenser 42 must pass. Also, in charging the condenser 40 it is desirable to utilize a resistor 92 for the purpose of stabilizing the timing circuit. To enable the potentiometer 90 to be mounted conveniently, it is mounted within the connection box 44 at the left side of the machine as shown in FIG. 1 of the drawings with a control knob extending through the upper surface of the connection box.

Before the welt severing knife 14 may be actuated without rendering the safety circuit operative the shaft 55 must be rotated to a position in which a secondary line switch LS1, more fully disclosed in the prior application, is closed. In this way the danger of improper actuation of the knife is minimized.

If the machine is to operate upon seWed-heel-seat shoes the selector switch element 144 is maintained in engagement with the SS contact and the operation of the machine is in the manner above indicated. If the machine is to be used in sewing regular Goodyear welt shoes from breast-line to breast-line, the selector switch element is moved into engagement with the BB contact. Under these conditions the manner of operation is similar to that employed in sewing sewed-heel-seat shoes except that the feeler and its switch 28 are rendered inoperative. shoes from breast-line to breast-line only, the welt is severed whenever a control treadle 94 (FIG. 4) is released at the end of a seam. As in the machine of theprior application, the control treadle 94 is pivotally mounted at 96 on the machine frame and is connected through a link 98, a lever 100, and a bell crank 102 to a micro-switch 104 arranged for normally closing a tripping circuit running between the knife actuating relay K3 and the contacts BB, which are connected by the:

regular Goodyear welt shoe approaching, he actuates the.

knee lever 32 to render the safety circuit operative.

Thereafter, when the end of the seam is reached he re-' leases the control treadle 94 to bring the machine to rest and to sever the welt. However, if a break in the thread or improperly tightened stitches are detected by the operator through failure of the tension wheel to rotate between the times when the knee lever is actuated and the control treadle is released, the machine may be brought to rest without severing the welt, so that new stitches may be inserted over those improperlyformed to repair the shoe without the presence of a break in the welt.

The nature and scope of the invention having been in dicated and a particular embodiment having been specifically described, what is claimed is:

1. A sewing machine for attaching parts of work together, said machine having stitch-forming, feeding, and guiding devices for the work parts including an intermittently actuated device for applying a stitch setting tension to the thread for each stitch formed by the stitch forming devices, means for performing an auxiliary operation during sewing, mechanism for actuating the auxiliary operation performing means including a solenoid and an armature connected to the auxiliary operation performing means, a current supply line and a normally inoperative safety circuit connecting the solenoid with the supply line, in combination with a time delay means acting after the stitch setting device tightens a stitch to render operative the normally inoperative safety circuit for 21 However, in sewing regular Goodyear welt:

aosnasv a period of time required to tighten the next succeeding stitch.

2'. An inseam sewing machine for attaching a Goodyear welt to a last supported shoe upper and a sole member, said machine having stitch forming, feeding, and guiding devices for the shoe parts including an intermittently. actuated device for applying a' stitch setting tension to the thread for each stitch formed by the stitch forming devices, a welt severing knife mounted for movement across the welt as it passes through the guiding devices, mechanism for actuating the knife to sever the welt, including a solenoid and an armature connected to the knife, a current supply line and a normally inoperative safety circuit actuated at the end of a seam to connect the solenoid with the supply line, in combination with a time delay circuit acting after the stitch setting device tightens a stitch to render operative the normally inoperative safety circuit for a period of time required to tighten the next succeeding stitch.

3. An inseam sewing machine for attaching a Goodyear welt to a last supported shoe upper and a sole member, said machine having stitch forming, feeding, and guiding devices for the shoe parts including an intermittently actuated device for applying a stitch setting tension to; the thread for each stitch formed by the stitch forming devices, a welt severing knife mounted for move ment across the welt as it passes through the guiding devices,.mechanism for actuating the knife to sever the welt, including a solenoid and an. armature connected to. the. knife, acurrent supply line and a normally in operative safety circuit. actuated at the end of a seam toconnect the solenoid with thesupply line, in-combinationiwith a time delay circuit acting after the stitch setting device. tightens a stitch to render operative the normally inoperativeisafety circuit for a period of time required to tighten the next succeeding stitch, a traction member about which the sewing thread passes, and electrical contacts actuated relatively to each other by the traction member whenever the traction member is shiftedvby the threadtfor' initiating theoperative periodof time for thenormally inoperative circuit.

4; An inseam sewing machine, for attaching a Goodyear welt to a last'supportedshoe upper and a sole member, said machine having stitch-forming, feeding, and guiding'devices for the shoe parts including an intermittently actuated device for applying a stitch setting tension to the thread foreach stitch formed by the stitch formingdevices, a welt severing knife mounted for move ment across the welt as it passes through the guiding devices, mechanism for actuating the knife to sever the welt, including a solenoid and an armature connected to the knife, acurrent supply line and a normally inoperative safety circuit actuated at the, end of a seam to connect the solenoid with, the supply line, in cornbination with a time delay circuit acting after the stitch setting device tightens a stitch to render operative the normally inoperative safety circuit for a period of time required to tighten the nextsucceeding stitch, a traction member about whichthe sewing thread passes, and electrical contacts actuated relatively to each other by the traction member whenever the traction member is shifted by the thread for initiating the operative period of time for the normally inoperative circuit, said time delay circuit including a condenser connected to one of the traction member actuated contacts and to the supply line to charge the condenser, and a relay having a coil connected to the condenser, providing a path of retarded discharge through the coil to render the knife actuating solenoid operative during the period of time required for the condenser to become discharged.

5. An inseam sewing machine for attaching a Goodyear welt to a last supported shoe upper and a sole member, said machine having stitch forming, feeding, and guiding devices for the shoe parts including an intermittently actuated device for applying a stitch setting tension to thethread for each stitchformed by the stitch forming mechanism for. actuating the knife to sever the welt, in:-

cluding a solenoid and an armature connected to the knife, a current supply line and a normally inoperative safety circuit actuated at the end of a seam to connect the solenoid with the supply line, in combination with a time, delay circuit acting after the stitch setting device tightens a stitch to render operative the normally inoperative safety circuit for a period of time required to tighten the next succeeding stitch, the stitch setting device comprising a take-up and the time delay circuit comprising a thread tension wheel against which the take-up acts in setting each stitch, a brake for imparting frictional resistance to the thread tension wheel and for insuring that the tension applied to the thread willreach a predetermined value while each stitch is being set and contacts actuated by the tension wheel.

6. An inseam sewing machine for attaching a Goodyear welt to a last supported shoe upper and a sole member, said machine having stitch-forming, feeding, and" guiding devices for the shoeparts, including an intermittently actuated device for applying astitch setting tension,

to the thread for'each stitch formed by the stitch forming devices, a welt severing knife mounted for movement across the welt as it passes through the guiding devices, mechanism for actuating the knife to sever the welt, including a solenoid, and an armature connected to the knife, a current supply line and a normally inoperative safety circuit actuated at the endiof a seam to connect the solenoid with the supply line, in combination with a time delay circuit acting after the stitch setting device,

tightens a stitch to render, operative the normally in-v operative safety circuit for a period of. time required .to tighten the next succeeding stitch, a traction member about which the sewing thread passes, electrical contacts, actuatedrelatively to each other by the traction member whenever the traction member is shifted by the thread.

being discharged,and means mechanically connected to the traction member for actuating the contacts between.

the supply line and the condenser when thread is drawn past the traction member.

7. An inseam sewing machine for attaching a Goodyear welt to a last supported shoe upper and a sole mem-v ber, said machine having stitch-forming, feeding, and

guiding devices for the shoe parts including an intermit-- tently actuated device for applying a stitch setting tension to the thread for each stitch formed by the stitch forming devices, a welt severing knife mounted for movement across the welt as it passes through the guiding devices, mechanism for actuating the knife to sever the welt, including a solenoid and an armature connected to the knife, a current supply line and a normally inoperative safety circuit actuated at the end of a seam to connect the solenoid with the supply line, in combination with a time delay circuit acting after the stitch setting device tightens a stitch to render operative the normally inoperative safety circuit for a period of time required to tighten the next succeeding stitch, the stitch. setting device comin setting eachtstitch, a brake applied to the thread tension wheel for insuring that the tension applied to the thread will reach a predetermined value while each stitch is being set and contacts actuated by the tension wheel, magnetic means attached to the thread tension wheel and disposed with its field extending into operative relation to the condenser charging contacts and high magnetic permeability means connected to the contacts for actuating them, first to open them and then to close them as the thread is drawn past the tension wheel.

8. An inseam sewing machine for attaching a Goodyear welt to a last supported shoe upper and a sole member, said machine having stitch-forming, feeding and guiding devices for the shoe parts including an intermittently actuated device for applying a stitch setting tension to the thread for each stitch formed by the stitch forming devices, a welt severing knife mounted for movement across the Welt as it passes through the guiding devices, mechanism for actuating the knife to sever the welt, including a solenoid and an armature connected to the knife, a current supply line and a normally inoperative safety circuit actuated at the end of a seam to connect the solenoid with the supply line, in combination with a time delay circuit acting after the stitch setting device tightens a stitch to render operative the normally inoperative safety circuit for a period of time required to tighten the next succeeding stitch, a traction member about which the sewing thread passes, electrical contacts actuated relatively to each other by the traction member whenever the traction member is shifted by the thread for initiating the operative period of time for the normally inoperative circuit, a condenser connected between one side of the supply line and the contacts to charge the condenser, a relay having a coil connected between the other side of the supply line and the condenser, and a resistor in circuit with the condenser providing a path of retarded discharge through the coil to render the circuit for the feeler switch operative during the time required for the condenser to become discharged.

9. An inseam sewing machine for attaching a Goodyear Welt to a last supported shoe upper and a sole member, said machine having stitch-forming, feeding and guiding devices for the shoe parts including an intermittently actuated device for applying a stitch setting tension to the thread for each stitch formed by the stitch forming devices, a welt severing knife mounted for movement across the welt as it passes through the guiding devices, mechanism for actuating the knife to sever the welt, including a solenoid and an armature connected to the knife, a current supply line and a normally inoperative safety circuit actuated at the end of a seam to connect the solenoid with the supply line, in combination with a time delay circuit acting after the stitch setting device tightens a stitch to render operative the normally inoperative safety circuit for a period of time required to tighten the next succeeding stitch, a traction member about which the sewing thread passes, electrical contacts actuated relatively to each other by the traction member whenever the traction member is shifted by the thread for initiating the operative period of time for the normally inoperative circuit, said time delay circuit including a condenser connected between one side of the supply line and the time initiating contacts to charge the condenser, a relay having a coil connected between the other side of the supply line and the condenser, providing a path of retarded discharge through the coil to render the circuit for the knife actuating solenoid operative during the time required for the condenser to become discharged, and a variable resistor in circuit with the time initiating contacts to enable the period of time to be changed.

10. (An inseam sewing machine for attaching a Goodyear welt to a last supported shoe upper and a sole member, said machine having stitch-forming, feeding, and guiding devices for the shoe parts including an intermittently actuated device for applying a stitch setting tension to the thread for each stitch formed by the stitch forming devices, a welt severing knife mounted for movement across the welt as it passes through the guiding devices, mechanism for actuating the knife to sever the welt, including a solenoid and an armature connected to the knife, a current supply line and a normally inoperative safety circuit actuated at the end of a seam to connect the solenoid with the supply line, in combination with a time delay circuit acting after the stitch setting device tightens a stitch to render operative the normally inoperative safety circuit for a period of time required to tighten the next succeeding stitch, a traction member about which the sewing thread passes, electrical contacts actuated relatively to each other by the traction member whenever the traction member is shifted by the thread for initiating the operative period of time for the normally inoperative circuit, said time delay circuit including a condenser connected to one side of the supply line, a relay having a coil connected to the condenser, providing a path of retarded discharge through the coil to render the circuit for the knife actuating solenoid operative during the period of time required for the condenser to become discharged, and a second condenser connected between certain of said time initiating contacts and the same side of the supply line, certain other of said contacts being connected to the other side of the supply line to charge said second condenser and to cause the charge on said second condenser to be transferred to the first mentioned condenser.

11. An inseam sewing machine for attaching a Goodyear welt to a last supported shoe upper and a sole member, said machine having stitch-forming, feeding, and guiding devices for the shoe parts including an intermittently actuated device for applying a stitch setting tension to the thread for each stitch formed by the stitch forming devices, a welt severing knife mounted for movement across the welt as it passes through the guiding devices, mechanism for actuating the knife to sever the welt, including a solenoid and an armature connected to the knife, a current supply line and a normally inoperative safety circuit actuated at the end of a seam to connect the solenoid with the supply line, in combination with a time delay circuit acting after the stitch setting device tightens a stitch to render operative the normally inoperative safety circuit for a period of time required to tighten the next succeeding stitch, a traction member about which the thread passes, stationary contacts, a movable contact actuated between the stationary contacts by the traction member whenever the traction member is shifted by the thread for initiating the period of time delay, said time delay circuit including a first condenser connected between certain of the stationary contacts and one side of the supply line to charge the condenser, a relay having a coil connected to the condenser and providing a path of retarded discharge through the coil to render the circuit for the knife actuating solenoid operative during the period of time required for the condenser to become discharged, and a second condenser connected to another of the stationary contacts to enable the second condenser to be charged and thereafter to connect the second condenser with the first condenser to cause the charge of the second condenser to be transferred to the first condenser as the traction member is shifted by the thread.

12. An inseam sewing machine for attaching a Goodyear welt to a last supported shoe upper and a sole member, said machine having stitch-forming, feeding and guiding devices for the shoe parts including an intermittently actuated device for applying a stitch setting tension to the thread for each stitch formed by the stitch forming devices, a welt severing knife mounted for movement across the welt as it passes through the guiding devices, mechanism for actuating the knife to sever the welt, including a solenoid and an armature connected to the knife, a current supply line and a normally inoperative safety circuit actuated at the end of a seam to connect the solenoid with the supply line, in combination with a time delay circuit acting after the stitch setting device tightens a stitch to render operative 11 the normally inoperative safety circuit for a period of time-.requiredto tighten the next succeeding stitch, and a. manual push button switch mounted on the machine for closing the circuit through the solenoid while bypassing the normally'inoperative safety circuit.

13. A sewing machine for attaching work parts, said machine having stitch-forming, feeding, and guiding devices for the work parts, including an intermittently actuated device for applying a stitch setting tension to the thread for each stitch formed, means for performing an auxiliary operation other than stitch forming on the work, parts, mechanism for actuating the auxiliary operation performing means including a solenoid and an annature connected to the auxiliary operation performing means, acurrent supply line and a normally inoperative safety circuit for connecting the solenoid with the supply line, in combination with time delay means acting after the stitch setting device tightens a stitch with a predetermined tension to render the normally inoperative safety circuit operative for a period of time required to tighten the next succeeding stitch.

14. A sewing machine for attaching work parts, said machine having stitch-forming, feeding, and guiding devices for the work parts, including an intermittently actuated. device for applying a stitch Setting tension to the thread for each stitch formed, means for performing an auxiliary operation other than stitch forming on the work parts, mechanism for actuating the auxiliary operation performing means including a solenoid and an armature connected to the auxiliary operation performing means, a. current supply line and a normally inoperative safety circuit for connecting the, solenoid with the supply line, in combination with time delay means acting after the stitch setting device tightens a stitch with apredetermined tension to, render the normally inoperativesafety circuit operative for a period of time required to tighten the next succeeding stitch, a traction member about which 12 the sewing thread passes, magnetic means attached to the traction member, contacts for controlling the safety circuit and high magnetic permeability means connected to the contacts within the field of the magnetic means to actuate the contacts intermittently whenever the thread is drawn from he traction member.

15. A sewing machine for attaching work parts, said machine having stitch forming, feeding, and guiding devices for the work parts including an intermittently actuated take-up for applying a stitch setting tension to the thread for each stitch inserted in the work parts, a thread tension wheel against the rotation of which the take-up acts in applying a stitch setting tension to the thread, auxiliary means for performing an operation other than forming and setting stitches, mechanism for actuating the auxiliary, means including a solenoid and an armature connected to-the auxiliary operation performing means, and a normally inoperative safety circuit actuated at the end of a seam to connect the solenoid with the supply line, in combination with mechanism for controlling the safety circuit, including magnetic means having a serrated pole piece attached to the thread tension wheel and contacts. electrically connected to the safety circuit and provided with a plate of high magnetic permeability mechanically connected to the contacts for actuating them intermittently as the thread is drawn past the tension wheel.

References Cited in the file of this patent UNITED STATES PATENTS 2,211,362 Bennett Aug. 13, 1940 2,381,250 Baurnann Aug. 7, 1945 2,581,960 Kronenwetter Jan. 8, 1952 2,885;9 80 Carter May 12, 1959 2,900,933 Carter Aug. 25, 1959

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