US3363594A

US3363594A - Automatic feed mechanism for sewing machines

Info

Publication number: US3363594A
Application number: US455151A
Authority: US
Inventors: Robert L Kosrow
Original assignee: Union Special Machine Co
Current assignee: Union Special Machine Co
Priority date: 1965-05-12
Filing date: 1965-05-12
Publication date: 1968-01-16
Anticipated expiration: 1985-01-16
Also published as: DE1685060A1

Description

R. KOSROW 37,363,594

AUTOMATIC FEED MECHANIS M FOR SEWING MACHINES Jan. 16, 1968 Filed May 12, 1965 6 Sheets-Sheet l Jan. 16, 1968 R. L. KOSROW 3,363,594

AUTOMATIC FEED MECHANISM FOR SEWING MACHINES Filed May 12, 1965 6 Sheets-Sheet 2 R. L. KOSROW 3,363,594

AUTOMATIC FEED MECHANISM FOR SEWING MACHINES Jan. 16, 1968 6 Sheets-Sheet 5 Filed May 12, 1965 wwwx Jan. 16, 1968 R. L. KOSROW 3,363,594

AUTOMATIC FEED MECHANISM FOR SEWING MACHINES Filed May 12, 1965 6 Sheets-Sheet 4.

l v I23 30 R. L. KOSROW 3,363,594

AUTOMATIC FEED MECHANISM FOR SEWING MACHINES Jan. 16, 1968 6 Sheets-Sheet 5 Filed May 12; 1965 FIG. 9

Jan. 16, 1968 R. KOSROW 3,36 ,594

AUTOMATIC FEED MECHANISM FOR SEWING MACHINES Filed May 12, 1965 6 Sheets-Sheet 6 United States Patent 3,363,594 AUTOMATIC FEED MECHANISM FOR SEWING MACHINES Robert L. Kosrow, Elk Grove Village, IlL, assignor to Union Special Machine Company, Chicago, 11]., a corporation of Illinois Filed May 12, 1965, Ser. No. 455,151 18 Claims. (Cl. 112-210) ABSTRACT OF THE DISCLOSURE A back tacking mechanism for a sewing machine in which first sensing means including a first photoelectric cell is effective to automatically feed the material being sewn in a forward direction, and second sensing means including a second photoelectric cell reverses the direction of feed for a period of time which is dependent upon the rate of discharge of a capacitor. The first sensing means then continues the advance of the material in the forward direction and is effective to automatically shut off the stitching mechanism of the machine when the trailing edge of the material passes therebeneath.

This invention relates to a sewing machine and more particularly to an automatically controlled feeding mechanism for changing the direction of feed of the material being sewn.

There has been developed an adjustable drive for the feeding mechanism of a sewing machine which is positive in action and highly efiicient. One such drive is disclosed, for example, in Daniel Patent No. 3,033,141, granted May 8, 1962. In drives of this type, the direction of feed of the material being advanced through the machine may be readily reversed, to perform back tacking or other stitching operations, in response to the actuation of a reversing lever by the machine operator. The machine also includes an additional manual control, customarily in the form of a foot treadle, for starting and stopping the feeding mechanism.

In order to prevent the possibility of the stitching be coming unravelled, the seam being sewn frequently is locked in place at the leading and trailing edges of the material through the use of locking or back tacking stitches. To perform a back tacking operation on machines of the foregoing type, it heretofore was necessary for the operator to slow down the machine sufficiently to be able to count the desired number of forward locking stitches, to then operate the reversing lever and count the number of reverse locking stitches, and to thereafter return to forward stitching for the sewing and completion of the seam. The operation required the use of both hands of the operator and was particularly disadvantageous in the formation of a back tack at the trailing edge of the material because of the desirability that the operator have his hands free to prepare succeeding pieces of material for seaming. The frequent actuation of the foot treadle and reversing lever in such prior machines has consumed an excessive amount of time and has otherwise proved deficient in several respects.

One general object of this invention, therefore, is to provide a new and improved feeding mechanism for sewing machines which enables the automatic control of the direction of feed.

More specifically, it is an object of the invention to provide such feeding mechanism which is effective to automatically reverse the direction of feed for a predetermined period of time.

Another object of the invention is to provide a feeding mechanism of the character indicated for automatically Patented Jan. 16, 1968 performing a back tacking operation at the trailing edge of the material being sewn.

A further object of the invention is to provide a novel feeding mechanism for sewing machines which is economical to manufacture and thoroughly reliable in operation.

In one illstrative embodiment of the invention, there is provided a sewing machine having a reversible feeding mechanism and a stitching mechanism which are connected through a drive clutch to a suitable source of power. The drive clutch is controlled by a foot treadle for initiating operation of the machine. To perform a back tacking or other reversing operation, the machine includes an automatic control system which is effective to actuate the feeding mechanism in both the forward and the reverse direction in accordance with a predetermined sequence without the intervention of the operator of the machine.

In accordance with one feature of the invention, the automatic control system comprises unique sensing means, such as a photoelectric cell and cooperating light source, for example, which is responsive to a preselected portion of the material being advanced through the stitching mechanism to change the direction of feed for a predetermined period of time. Thereafter, the operation of the feeding mechanism is automatically continued in the initial direction to complete the seam.

In accordance with another feature of the invention, in several advantageous embodiments, there is provided additional photoelectric means for conditioning the 111achine for automatic operation and for bringing the machine to a stop upon the completion of the seam. The arrangement is such that the machine automatically forms a back tack along the trailing edge of the material and then shuts itself off without the intervention of the operator. With this arrangement, the operator is free to arrange successive pieces of material for stitching or to perform other ancillary operations during the formation of the seam.

In accordance with the further feature of certain goo-d embodiments of the invention, automatic operation of the machine is initiated by a manually controlled switch which may be actuated at substantially any point during the formation of the seam. The machine thereafter automatically completes the seam, irrespective of its length, and forms a back tack of preselected length at the trailing edge of the material.

In accordance with a still further feature of the invention, in some embodiments, the actuation of the control switch to initiate automatic operation also is effective to disengage the foot treadle of the machine until the ma- 1 chine has been brought to a stop following the completion of the seam.

The present invention, as well as further objects and features thereof, will be understood more clearly and fully from the following description of certain preferred embodiments, when read with reference to the accompanying drawings, in which:

FIGURE 1 is a front elevational view of a sewing machine in accordance with one illustrative embodiment of the invention, with certain parts shown broken away;

FIGURE 2 is a side elevational view of the machine as seen from the left of FIGURE 1, with portions of the supporting structure omitted for purposes of clarity;

FIGURE 3 is a bottom view of a portion of the machine with the cover plate removed;

FIGURE 4 is a transverse vertical sectional View taken along the line 4-4 in FIGURE 3;

FIGURE 5 is a horizontal sectional view taken generally along the line 5-5 in FIGURE 1;

FIGURE 6 is a horizontal sectional view taken along the line 6-6 in FIGURE 1;

FIGURE 7 is an enlarged front elevational view of the portion of the machine shown in FIGURE 6;

FIGURE 8 is a schematic wiring diagram of a portion of the automatic control circuit for the machine;

FIGURE 9 is a schematic wiring diagram of another portion of the automatic control circuit;

FIGURE 10 is a side elevational view similar to a portion of FIGURE 2 but illustrating a sewing machine in accordance with another illustrative embodiment of the invention; and

FIGURE 11 is a front elevational view of a portion of the machine shown in FIGURE 10.

Referring to the drawings, there is shown a lock-stitch sewing machine of the general type disclosed in somewhat greater detail in Covert Patent 2,977,910, granted Apr. 4, 1961. The machine includes a frame structure indicated generally at 15 which supports a sewing table 16. A vertical standard 17 extends upwardly from the table 15 and is provided with an overhanging arm 18 which terminates in a needle head 19. The head 19 includes a vertically reciprocable stitching mechanism 20 of conventional construction which is controlled by a drive shaft (not visible in the drawings) longitudinally disposed within the arm 18. The end of this shaft opposite that adjacent the head 19 is affixed to a combined handwheel and pulley 22.

The pulley 22 is driven through a V-belt 25 by a drive pulley 26. This latter pulley is mounted beneath the sewing table 16 and is connected to one side of a combined clutch-brake mechanism 28, the other side of which is operated by an A.C. motor or other suitable source of driving power. The clutch-brake mechanism 28 iilustratively may be of the type disclosed in Ingalls Patent 2,739,251, granted Mar. 20, 1956. The mechanism 28 includes an actuating pin 34 which is movable to the left from the position shown in FIGURE 1 to engage the clutch portion of the mechanism and transfer driving power from the motor 30 to the pulley 26, thereby operating the stitching mechanism 20 through the belt 25, the pulley 22 and the drive shaft within the overhanging arm 18. Upon movement of the pin 34 to the right, the clutch is disengaged, and positive braking action is applied to the pulley 26 to rapidly arrest the stitching mechanism. Power is supplied to the motor 30 through a cable 36, a main on-oif switch 37 and a plug 38.

The movements of the actuating pin 34 are controlled by an L-shaped lever 39 which is pivotally supported adjacent one end thereof by a pin 40. The opposite end of the lever 39 is fixedly but adjustably secured to a substantially flat plate 41. Pivotally supported by the plate 41 is an upstanding lever 42 which is offset adjacent its upper end and is connected to the plunger 43 of an automatic take-over solenoid 44. This solenoid is carried by a plate 45 which is mounted on the housing for the motor 30 at the end thereof opposite that adjacent the clutchbrake mechanism 28. The plate 45 additionally supports a braking solenoid 46 having a plunger 47 which is coaxially aligned with the plunger 43. The solenoid 46 is adjustably held in place on the plate 45 by screws 48 and is positioned such that the plunger 47 bottoms within the solenoid when it is in its energized condition. The plunger 43 of the solenoid 44 is similarly positioned by adjusting the angular relationship between the lever 39 and the plate 41 through the use of screws 49.

The facing ends of the

plungers

43 and 47 are fixedly interconnected such that the plungers move in unison. Upon energization of the take-over solenoid 44, the

plungers

43 and 47, together with the offset lever 42, are carried in a downward direction to pivot the lever 38 counterclockwise about the pin and thereby move the actuating pin 34 in a direction to engage the clutch portion of the clutch-brake mechanism 28. Energization of the braking solenoid 46 urges the lever 42 upwardly and pivots the lever 39 clockwise to move the pin 34 in a direction to provide positive braking action, for purposes that will become more fully apparent hereinafter.

A pitman assembly 59 is connected between the flat plate 41 and a foot treadle 51. The assembly 50 comprises two

elongated rods

52 and 53 which extend downwardly from the plate 41 in spaced-apart parallel relationship with each other. The upper end of the rod 52 is secured to the plate 41 by a ball connection 54, and a clamp 55 is fastened adjacent the lower end of the rod. The rod 53 is connected by a ball connection 56 to the foot treadle 51, and this latter rod extends upwardly from the foot treadle and is slidably disposed in a suitable aperture in the clamp 55.

Positioned around the

rods

52 and 53 between the plate 41 and the clamp 55 is a release clamp 58. As best shown in FIGURES 6 and 7, the clamp 53 is maintained in rigid relationship with the rod 52 by set screws 5Q. A lever 60 is pivotally supported by the clamp 58 for movement about a vertical axis. In the illustrated position, this lever is resiliently held against a locking portion 62 of the rod 53 by a coil spring 64. The portion 62 is of reduced diameter such that the lever 66 normally prevents vertical movement of the rod 53 with respect to the rod 52. The lever 66 is connected by a horizontally extending link 65 to a treadle release solenoid 66 (FIG- URE 1). Upon energization of the solenoid 66, the lever 60 is pivoted in a counterclockwise direction from the position shown in FIGURE 6 to permit free sliding movement between the

rods

52 and 53.

The material feeding mechanism of the machine is best shown in FIGURES 35. This mechanism includes a horizontally extending drive shaft 70 which is journalled beneath the table 16 and is suitably connected to the drive shaft within the overhanging arm 18 by approprb ate gearing (not visible in the drawings) in the vertical standard 17. The drive shaft 70 is effective to produce a four-motion feeding movement of a feed bar 71 and an attached feed dog 72 (FIGURE 4). Thus, as more fully described in the Daniel patent referred to above, the shaft 70 includes an eccentric 74 which is connected through a link 75 to a depending arm 76 afiixed to the feed bar 71. As the shaft 70 rotates, the forward end of the bar 71 (the right end, as viewed in FIGURE 4) moves upwardly and downwardly to produce corresponding movements of the feed dog 72. A second eccentric 78 on the shaft '76 is connected through a link 79 to a feed rocker 80 which is pivotally supported on a horizontally extending stationary shaft 81. The rocker 8% is provided with an arcuate slot 82 which extends substantially equal distances above and below the axis of the shaft 81. This slot carries a slide element 83 which is connected through a link 84 to the depending arm 76. As the drive shaft 70 rotates, the rocking movement of the rocker 8 0 acts on the element 83, the link 84 and the arm 76 to produce longitudinal reciprocating motion of the feed bar '71 and the feed dog 72. This movement, when coupled with the movement of the feed dog in response to the eccentric 74, causes the feed dog to describe a generally elliptical path, as shown schematically at 85 in FIGURE 4.

The direction and extent of movement of the feed dog 72 along its elliptical path is determined by the position of the slide element 83 within the arcuate slot 82. In cases in which the element 83 is disposed within the slot 82 above the axis of the stationary shaft 81, the feed dog 72 moves along its path in a direction to advance the material being sewn forwardly through the stitching mechanism 20 (FIGURE 1). With the element 83 below the axis of the shaft 31, the feed dog moves in the opposite or reverse direction. The greater the upward or downward movement of the element 83 from its dead center position, the greater will be the longitudinal movement of the feed dog, thereby providing a control over the length of the stitches.

As best shown in FIGURES 3 and 5 a bent lever 85 interconnects the slide element 83 and one end of a rock shaft 87. The shaft 87 is supported beneath the table 16 in spaced parallel relationship with the drive shaft 70, and its opposite end is connected through

arms

88 and 89 to a forwardly extending shaft 90. This latter shaft is provided with a reversing lever 92 (FIGURE 1) which may be controlled either manually by the operator of the machine or automatically by a reversing solenoid 94. The solenoid 94 is mounted on the vertical standard 17 and is adjustably held in place by screws 95. Upon movement of the lever 92 in a counterclockwise direction, as viewed in FIGURE 1, the slide element 83 (FIGURE 4) is urged progressively above the level of the stationary shaft 81 to operate the feeding mechanism in the forward direction. Conversely, clockwise movement of the lever 92 carries the element 83 progressively below the level of the shaft 81 to reverse the direction of feed.

The reversing solenoid 94, together with the takeover solenoid 44, the braking solenoid 46 and the threadle release solenoid 66, are operated under the control of a lever 97 and two

photoelectric cells

98 and 99 and cooperating light sources 100 and 181. The lever 97 is supported on the upper surface of the table 16 and includes two sets of normally

open switch contacts

103 and 104, only the contacts 103 being visible in FIGURE 1. Upon movement of the lever 97 to the right from the position shown in this figure, the

contacts

103 and 104 close momentarily to initiate the automatic operation of the sewing machine in a manner to be more fully described hereinafter.

The light source 1110 for the photoelectric cell 98 is clamped to the needle head 19 immediately above the stitching mechanism 20. The source 109 directs a beam of light in a downward direction through a transparent plate (not visible in the drawings) in the table 16 to a prism 105 mounted therebeneath. The prism 195 bends the light beam at right angles and directs it toward the photocell 98 which is suitably affixed to the lower surface of the table. The light source 101 and the photoelectric cell 99 are clamped to the needle head 19 adjacent the outfeed side of the stitching mechanism 20, that is, to the right of the mechanism as viewed in FIG- URE 2. The beam of light from this latter source is reflected by the needle plate of the machine toward the photocell 99.

The

switch contacts

103 and 104, the

photoelectric cells

98 and 99, and the

light sources

188 and 101 are electrically connected in a control circuit which is effective to actuate the take-over solenoid 44, the braking solenoid 46, the treadle release solenoid 66 and the reversing solenoid 94 in predetermined relationship with each other. Several of the individual components of the control circuit are mounted on a panel 108 which is disposed above the table 16 and is supported by an upstanding rod 189. These components include five twoposition switches 110114 and a pilot light 115 for lIlClleating the condition of the circuit. Also mounted on the panel 108 is a variable resistor 117 which controls the duration of application of positive braking action to the machine and a variable resistor 118 for controlling the duration of reverse operation.

The control circuit is shown schematically in FIG- URES 8 and 9. The portion of the circuit illustrated in FIGURE 8 includes the photocell 98 and its light source 100 and is effective to condition the machine for automatic operation and to bring it to a stop upon the completion of a seam. The circuit portion shown .in FIGURE 9 includes the photocell 99 and the light source 101 and provides control over the formation of a back tack through energization of the reversing solenoid 94. The deenergized positions of the various relay contacts in the control circuit are shown by full lines in these 6 figures, while the energized positions of the contacts are shown by dotted lines.

Referring to FIGURE 8, the circuit includes

supply lines

120 and 121 which lead to opposite sides of an AC. power source 122 through the two-position switch 110. The pilot light is connected across the lines and 121 and is energized upon the closing of the switch 110 to provide an indication that the circuit is in an active condition. The source 122 also is connected to the motor 30 by

conductors

119 and 123 and the onoff switch 37.

The

lines

120 and 121 supply power to a photocell circuit shown schematically at 124. The circuit 124 is of conventional construction and is effective to produce an output signal in response to the interruption of the light beam from the light source 100 to the photocell 98. This output signal appears in the winding of a relay 125 having normally open contacts 126. One of the contacts 126 is connnected through the two-position switch 111 to the line 120, while the other contact leads through the winding 128a of a multicontact relay 128, a conductor 129, the manually controlled switch 103 and

conductors

130 and 131 to the line 121.

The relay 128 is provided with normally

open contacts

132 and 133 and transfer

contacts

138, 139 and 140. The contacts 132 are interposed between the conductor 129 and the common terminal of the conductors 131i and 131. Upon energization of the relay 128, the contacts 132 are moved to their closed (dotted-line) position to complete a holding circuit for the winding 128a. One of the contacts 133 is connected to a conductor 135 leading to the supply line 120, while the other contact leads to a parallel circuit comprising the take-over solenoid 44 and the treadle release solenoid 66. The circuit is completed through the two-position switch 112 and a conductor 136 to the line 121.

The transfer contacts of the relay 128 comprise a movable contact 138 and two

stationary contacts

139 and 140. The movable contact 138 is connected to the negative side of a condenser 142, the positive side of which leads through a conductor 143 to one terminal of the winding of a relay 145. The opposite terminal of this winding is connected to the stationary contact 139 by a conductor 146. Connected in parallel across the relay winding is a series circuit including a resistor 147 and the variable resistor 117. In addition, the anode of a diode rectifier 148 is connected to the conductor 143, while the cathode of the rectifier leads through a resistor 149 to the supply line 121. In the deenergized condition of the relay 128, the movable contact 138 is maintamed in engagement with the contact 139. Upon energization of the relay, the contact 138 transfers from the contact 139 to the contact 14%), thereby completing a circuit from the condenser 142, the contacts 138 and and a conductor 150 to the supply line 129.

The relay 145 includes normally open contacts 152 which are interposed between the supply line 128 and one terminal of the braking solenoid 46. The opposite terminal of the solenoid 46 is connected through the two-position switch 113 to the supply line 121.

In the portion of the control circuit shown in FIG- URE 9, the

supply lines

120 and 121 are connected from the AC. source 122 to a photoelectric circuit 155. The circuit 155 is generally similar to the circuit 124 of FIG- URE 8 and is effective to produce an output signal in the Winding of a relay 156 upon the interruption of the light beam from the light source 191 to the photocell 99. The relay 156 includes normally open contacts 157. One of the contacts 157 is connected by a conductor 158 to the line 120, while the other contact leads to one terminal of the winding 169a of a multicontact transfer relay The multicontact relay 161) includes a first set of transfer contacts which comprise a movable contact 162 and two

stationary contacts

163 and 164. The movable contact 162 is connected to the terminal of the winding 160a opposite that leading to the supply line 120. The stationary contact 163 is connected to the supply line 121 along a path which extends through the manually operable switch contacts 1114 and

conductors

165 and 166, while the stationary contact 164 leads to the common terminal of these conductors. Upon energization of the relay 160, the contact 162 transfers from the contact 163 to the contact 164 to complete a holding circuit for the relay.

The relay 160 also includes a movable contact 167 and two stationary contacts 168 and 16'9. The contact 167 is connected to the negative terminal of a condenser 1719, the positive terminal of which leads through a conductor 171, the winding of a relay 172 and a conductor 173 to the stationary contact 168. A resistor 175 and the variable resistor 118 are arranged in series between the

conductors

171 and 173. The anode of a diode rectifier 178 is connected to the conductor 171, while the cathode of the rectifier leads through a resistor 179 to the supply line 121. The supply line 120 is connected to the contact 169 by a conductor 180. The relay 172 is provided with normally open contacts 182 which are interposed between the supply line 120 and one terminal of the reversing solenoid 94. The opposite terminal of the solenoid 94 leads through the on-off switch 114 to the supply line 121.

At the start of a particular sewing operation, the operator of the machine moves the two-position switches 110-114 on the control panel 108 (FIGURE 1) to their closed positions. In addition, the on-off switch 37 is moved to its on position to energize the drive motor 30. The pieces of material to be sewn together are then placed on the table 16 and are advanced through the stitching mechanism 20 by the feed dog 72 (FIGURE 4). The operation of the mechanism 26 and the feed dog 72 is initiated by depressing the foot treadle 51 to move the pitrnan assembly 50 in a generally downward direction, as viewed in FIGURE 1, thereby pivoting the L-shaped lever 39 counterclockwise about the pin 40 to carry the actuating pin 34 to the left and thus engage the clutch portion of the clutch-brake mechanism 28. During the time the machine is under manual control, the stitching and feeding mechanisms may be arrested by moving the treadle 51 in the opposite direction to carry the pin 34 to the right and provide positive braking action by means of the braking portion of the mechanism 28. Should the operator for any reason desire to reverse the direction of feed during the formation of the seam, such as to produce a back tack at the leading edge of the material, for example, the reversing lever 92 is actuated to change the direction of movement of the feed dog 72 along its elliptical path in the manner described heretofore.

As the operator of the machine inserts the leading edge of the material into the stitching mechanism 20, the beam of light from the light source 100 to the photoelectric cell 98 is interrupted to produce an output signal in the winding of the relay 125 (FIGURE 8). The relay 125 is thus energized to close its contacts 126, thereby conditioning the multicontact relay 128 for energization to control the sewing operation automatically. The relay 128 remains deenergized at this point, however, because of the open circuit at the contacts 103.

In a similar manner, the leading edge of the material moving beneath the light source 1151 (FIGURE 9) interrupts the light beam therefrom to produce an output si nal in the winding of the relay 156, thereby energizing the relay and closing its contacts 157. As these contacts close, one terminal of the relay winding 160a is connected to the supply line 126, but the relay 160 remains deenergized because of the open contacts 104 between the opposite terminal of the winding 166a and the supply line 121. The machine is thus conditioned for automatic operation.

The formation of the seam continues under the manual control of the foot treadle 51 until such time as the operator actuates the automatic control lever 97. The lever 97 may be operated at substantially any convenient point during the formation of the seam. Upon actuation of the lever, the contacts 103 and 194 close momentarily to initiate automatic operation of the machine under the control of the take-over solenoid 44, the braking solenoid 46, the treadle release solenoid 66 and the reversing solenoid 94.

Referring to FIGURE 8, the closure of the contacts 163 completes a circuit for the winding 128a of the multicontact re-lay 128. This circuit follows a path from the supply line 121), the two-position switch 111 and the relay contacts 126 to one terminal of the winding 128a and from the opposite terminal of the winding through the conductor 129, the contacts 103 and the

conductors

130 and 131 to the supply line 121. The relay 128 is thus energized to close the

contacts

132 and 133 and to transfer the contact 138 from the contact 139 to the contact 140. The closure of the contacts 132 completes a holding circuit for the relay winding, While the closure of the contacts 133 is effective to energize the take-over solenoid 44 and the treadle release solenoid 66. The energizing circuit for the

solenoids

44 and 66 may be traced from the line 126, the conductor 135 and the contacts 133 to one common terminal of the solenoids and then back from the other common terminal through the twoposition switch 112 and the conductor 136 to the supply line 121. As the contact 138 transfers from the contact 139 to the contact 140, a circuit is completed from the supply line 120, the conductor and the

contacts

138 and 140 to the negative terminal of the condenser 142 and from the positive terminal of this condenser through the rectifier 148 and the resistor 149 to the supply line 121, thereby charging the condenser to a DC. potential.

The energization of the take-over solenoid 44 moves its plunger 43 (FIGURE 1) in a downward direction to similarly move the offset lever 42 and the plate 41. The L-shaped lever 39 thereupon pivots about the pin 40 to urge the actuating pin 34 of the clutch-brake mechanism 28 in a direction to continuously engage the clutch portion of the mechanism. Simultaneously, the ener-gization of the treadle release solenoid 66 pivots the lever 60 in a counterclockwise direction, as viewed in FIGURE 6, to withdraw the lever from the locking portion 62 of the elongated rod 53. As the lever 61) moves away from the portion 62, the rod 53 is free to slide in an axial direction relative to the rod 52. The connection between the foot treadle 51 and the clutch-brake mechanism 28 is thus interrupted as long as the solenoid 66 remains energized.

As the contacts 104 (FIGURE 9) close in response to the operation of the lever 97, an energizing circuit is completed for the winding a of the mu-lticontact relay 160. This circuit may be traced from the supply line 120, the conductor 158, the relay contacts 157, the winding 160a, the

relay contacts

162 and 163, the contacts 164 and the

conductors

165 and 166 to the supply line 120. Upon the energization of the relay 160, the contact 162 transfers from the contact 163 to the contact 164, thereby completing a holding circuit for the winding 1612a, and the contact 167 transfers from the contact 168 to the contact 169. The engagement of the

contacts

167 and 169 serves to connect the negative side of the condenser 17!) to the supply line 120, thus placing a charge across the condenser. The relay 172 remains in its deenergized condition at this point, however, because of the break in the circuit between the

contacts

167 and 168.

As the trailing edge of the material being sewn reaches the stitching mechanism 20, the interruption of the light beam from the source 191 is discontinued. The light from the source 101 again strikes the photocell 99 to deenergizc the relay 156, thereby opening the contacts 157 and deenergizing the relay 161 The transfer contact 167 thereupon moves from the stationary contact 169 to the stationary contact 168, and a discharge path is completed for the condenser 170 through the winding of the relay 172. The relay 172 is thus energized for a period of time which is dependent upon the time constant of the con denser 170 and the resistance of the variable resistor 118 and the resistor 175. Energization of the relay 172 closes its contacts 182 to energize the reversing solenoid 94, thereby moving the lever 92 to the right, as viewed in FIGURE 1, to reverse the direction of feed of the material in the manner described heretofore.

As indicated heretofore, the light source 101 is supported adjacent the stitching mechanism 20. The position of the source 101 is such that the energization of the reversing solenoid 94 takes place at the same time that the trailing edge of the material passes beneath the stitching mechanism and the last stitch is completed. The operation of the feeding mechanism continues in the reversed directon until the condenser 170 discharges sufficiently to permit deenergization of the relay 172. During the discharge of the condenser, the stitching mechanism illustratively produces from six to twelve back tacking stitches which are superimposed over the forward line of stitching adjacent the trailing edge of the material. Upon the deenergization of the relay 172, the contacts 182 open to deenergize the reversing solenoid 94. The operation of the feeding mechanism in the forward direction is thereupon automatically resumed to produce an additional line of forward stitching at the trailing edge.

As the trailing edge of the material passes beneath the light source 100 (FIGURE 8), its light beam again reaches the photocell 98, thereby deenergizing the relay 125. Upon the deenergization of this relay, the contacts 126 open to deenergize the multicontact relay 128 and open the

contacts

132 and 133. The opening of the contacts 132 breaks the holding circuit for the relay winding 128a, while the opening of the contacts 133 is effective to deenergize the take-over solenoid 44 and the treadle release solenoid 66. The solenoid 44 is thus no longer effective to hold the actuating pin 34 (FIGURE 1) for the clutch-brake mechanism 28 in its clutch-engaged position. Deenergization of the solenoid 66 releases the spring biased lever 60 (FIGURES 6 and 7), and the lever 60 rides against the cylindrical surface of the rod 53 until such time as the locking portion 62 of this rod is moved to a position adjacent the lever. The spring 64 thereupon draws the lever into contact with the locking portion to reestablish the connection between the foot treadle 51 and the clutch-brake mechanism 28.

The deenergization of the multicontact relay 128 also is effective to transfer the movable contact 138 from the stationary contact 140 to the stationary contact 139. A discharge path is thus completed for the condenser 142 through the winding of the relay 145. This relay is thereupon energized for a period of time which is dependent upon the time constant of the condenser 142 and the resistance of the variable resistor 117 and the resistor 147. Upon energization of the relay 145, its contacts 152 close to energize the braking solenoid 46, thereby actuating the levers 42 and 39 (FIGURE 1) in a direction to operate the braking portion of the clutch-brake mechanism 28 in the manner described above. The stitching and feeding mechanisms of the machine are thus rapidly and automatically brought to a stop.

The variable resistor 117 is adjusted by the operator of the machine to insure that the condenser 142 discharges through the winding of the relay 145 for a period of time sufficient to maintain the braking solenoid 46 energized until the machine has come to a complete stop. In a similar manner, the variable resistor 118 is adjusted to predetermine the time during which the reversing solenoid 94 remains energized to operate the feeding mechanism in the reverse direction. The resistor 118 thus provides a precise control over the length of the back tack.

Referring to FIGURES 10 and 11, there is shown a portion of a sewing machinewhich is representative of another illustrative embodiment of the invention. The machine 185 includes a light source 186 and a cooperating photocell 187 which are mounted on a plate 188 by means of a bracket 189. A light source 190 and a photocell 191 similarly are secured by a bracket 192 to a plate 193. The

plates

188 and 193 are fixedly but adjustably fastened by screws 195 to a support plate 196 which is carried adjacent the upper portion of the needle head 197 of the machine. The positions of the

plates

188 and 193 may be readily varied by loosening the screws 195, to similarly vary the locations of the photocells and light sources carried thereby.

Extending downwardly from the

light sources

186 and 190 and the photocells 187 and 191 are four

elongated rods

200, 201, 202 and 203, respectively. These rods are fabricated of Lucite or other transparent material. The upper ends of the

rods

200 and 202 are attached to the plate 188 by a bracket 205, While the upper ends of the

rods

201 and 203 are secured to the plate 193 by a bracket 206. The lower ends of the respective pairs of rods are suitably held apart, as by

brackets

207 and 208, and are oriented in spaced juxtaposition with the reflective throat plate 210 of the machine.

In operation, the light beam from the source 186 passes along the rod 2-00, is reflected by the throat plate 210 and is directed through the rod 202 to the photocell 187. Similarly, the light beam from the source 190 moves along the rod 201, is reflected by the plate 210 and then passes through the rod 203 to the photocell 191. These light beams are successively interrupted as the leading edge of the material to be sewn passes through the stitching mechanism of the machine. The

sources

186 and 190 and the photocells 187 and 191 are electrically connected in a manner similar to the

sources

101 and 100 and the

photocells

99 and 98, in that order, described heretofore. By employing the transparent rods 200-203, the

sources

186 and 190 and the photocells 187 and 191 may be mounted adjacent the upper portion of the machine in spaced relationship with the stitching mechanism to provide the operator with extremely good visibility of the line of stitching being sewn.

In the illustrated embodiments of the invention, the various photocells, light sources and cooperating circuitry are effective to perform certain of their automatic control functions in response to the appearance of the trailing edge of the material at the stitching mechanism of the machine. In other good arrangements, these components are responsive to other preselected portions of the material. As an illustration, the photocell 99 (FIG- URE 9), the light source 101 and the associated circuitry may be employed to automatically reverse the direction of feed intermediate the edges of the material in response to a suitable change in color, pattern, etc., or upon the appearance of an appropriate mark at a preselected point along the seam.

The terms and expressions which have been employed are used as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding any equivalents of the features shown or described or portions thereof, but it is recognized that various modifications are possible within the scope of the invention claimed.

What is claimed is:

1. In a sewing machine having a power source and a stitching mechanism operated by said power source, the combination comprising a feeding mechanism driven by said power source for advancing material through said stitching mechanism, reversing means cooperating with said feeding mechanism for changing the direction of feed of said material, sensing means supported adjacent said stitching mechanism for producing an output signal upon the appearance of a preselected portion of said material thereat, and circuit means interconnecting said sensing means and said reversing means for operating the same in response to said output signal, to automatically change the direction of feed of the material for a predetermined period of time, said circuit means including electrical discharge means cooperating with said reversing means for controlling the period of operation thereof.

2. In a sewing machine having a power source and a stitching mechanism operated by said power source, the combination comprising a feeding mechanism driven by said power source for advancing material through said stitching mechanism in a given direction, reversing means cooperating with said feeding mechanism for changing the direction of feed of said material, first sensing means supported by said machine, means connected to said first sensing means and cooperating with said feeding mechanism for automatically feeding said material through said stitching mechanism in said given direction, second sensing means supported by said machine for producing an output signal upon the appearance of a preselected portion of said material at said stitching mechanism, and means interconnecting said second sensing means and said reversing means for o erating the same in response to said output signal, to automatically change the direction of feed of the material for a predetermined period of time, said feeding mechanism thereafter continuing to advance said material through said stitching mechanism in said given direction.

3. In a sewing machine having a power source and a stitching mechanism operated by said power source, the combination comprising a feeding mechanism driven by said power source for advancing material through said stitching mechanism, manually operable reversing means cooperating with said feeding mechanism for changing the direction of feed of said material, first sensing means supported by said machine, means connected to said first sensing means and cooperating with said feeding mechanism for automatically feeding said material through said stitching mechanism in a forward direction, second sensing means supported adjacent said stitching mechanism for producing an output signal upon the appearance of a preselected portion of asid material thereat, and means interconnecting said second sensing means and said reversing means for operating the same automatically in response to said output signal, to change the direction of feed of the material.

4. In a sewing machine having a power source and a stitching mechanism operated by said power source, the combination comprising a feeding mechanism driven by said power source for advancing material through said stitching mechanism in a given direction, reversing means cooperating with said feeding mechanism for changing the direction of feed of said material, manually operable means, connections between said manually operable means and said feeding mechanism for operating the same under manual control, circuit means for automatically operating said feeding mechanism to advance said material through said stitching mechanism in said given direction independently of said manually operable means, photoelectric means supported adjacent said stitching mechanism for producing an output signal upon the appearance of a preselected portion of said material thereat, and means interconnecting said photoelectric means and said reversing means for operating the same in response to said output signal during the automatic operation of said feeding mechanism to change the direction of feed of the material for a predetermined period of time, said feeding mechanism thereafter continuing the automatic advance of said material through said stitching mechanism in said given direction under the control of said circuit means.

5. In a sewing machine having a power source and a stitching mechanism operated by said power source, the combination comprising a feeding mechanism driven by said power source for advancing material through said stitching mechanism in a given direction, reversing means cooperating with siad feeding mechanism for changing the direction of feed of said material, circuit means cooperating with said feeding mechanism for matically controlling the same, said circuit means including a manually operable switch for initiating the automatic operation of said feeding mechanism at substantially any point during the advance of said material through said stitching mechanism, photoelectric means supported adjacent said stitching mechanism for producing an output signal upon the appearance of a preselected portion of said material thereat, and means interconnecting said photoelectric means and said reversing means for operating said reversing means in response to said output signal during the automatic operation of said feeding mechanism, to change the direction of feed of the material for a predetermined period of time, said feeding mechanism thereafter continuing the automatic advance of said material through said stitching mechanism in said given direction under the control of said circuit means.

6. In a sewing machine having a power source and a stitching mechanism operated by said power source, the combination comprising a feeding mechanism driven by said power source for advancing material through said stitching mechanism in a given direction, reversing means cooperating with said feeding mechanism for changing the direction of feed of said material, manually operable means, connections between said manually operable means and said feeding mechanism for operating the same under manual control, circuit means for automatically operating said feeding mechanism to advance said material through said stitching mechanism in said given direction independently of said manually operable means, said circuit means including a switch controlled by the operator of the machine for initiating the automatic operation of said feeding mechanism at substantially any point during the advance of said material through said stitching mechanism, photoelectric means supported by said machine for producing an output signal upon the appearance of a preselected portion of said material at said stitching mechanism, and means interconnecting said photoelectric means and said reversing means for operating the same in response to said output signal during the automatic operation of said feeding mechanism, to change the direction of feed of the material for a predetermined period of time, said feeding mechanism thereafter continuing the automatic advance of said material through said stitching mechanism in said given direction under the control of said circuit means.

7. In a sewing machine of the character set forth in claim 6, said photoelectric means including a photoelectric cell and a light source for directing a beam of light toward said cell, said beam of light being interrupted by the material being advanced through said stitching mechanism.

8. In a sewing machine having a power source and a stitching mechanism operated by said power source, the combination comprising a feeding mechanism connected to said power source for advancing material through said stitching mechanism in a given direction, reversing means cooperating with said feeding mechanism for changing the direction of feed of said material, circuit means connected to said feeding mechanism for automatically controlling the same, said circuit means including a manually operable switch for initiating the automatic operation of said feeding mechanism at substantially any point during the advance of said material through said stitching mechanism, photoelectric means supported adjacent said stitching mechanism for producing an output signal upon the appearance of a preselected portion of said material thcreat, means interconnecting said photoelectric means and said reversing means for operating said reversing means in response to said output signal during the automatic operation of said feeding mechanism, to change the direction of feed of the material for a predetermined period of time, said feeding mechanism thereafter continuing the automatic advance of said material through said stitching mechanism in said given direction under the control of said circuit means, and means controlled by said circuit means for disconnecting said feeding mechanism from said power source as the trailing edge of said material leaves said stitching mechanism.

9. In a sewing machine having a power source and a stitching mechanism operated by said power source, the combination comprising a reversible feeding mechanism driven by said power source for advancing material through said stitching mechanism, first manually operable means, connections between said first manually operable means and said feeding mechanism for operating the same under manual control, second manually operable means for controlling said feeding mechanism to reverse the direction of feed of the material, circuit means for automatically operating said feeding mechanism to advance said material through said stitching mechanism in a given direction independently of said first manually operable means, photoelectric means supported adjacent said stitching mechanism for producing an output signal upon the appearance of a preselected portion of said material thereat, and means interconnecting said photoelectric means and said second manually operable means for operating the same automatically in response to said output signal during the automatic operation of said feeding mechanism, to change the direction of feed of the material for a predetermined period of time, said feeding mechanism thereafter continuing the automatic advance of said material through said stitching mechanism in said given direction under the control of said circuit means.

10. In a sewing machine having a power source and a stitching mechanism operated by said power source, the combination comprising a reversible feeding mechanism driven by said power source for advancing material through said stitching mechanism, means interconnecting said power source and said feeding mechanism, reversing means for controlling said feeding mechanism to reverse the direction of feed of the material, first photoelectirc means supported by said machine, circuit means connected to said first photoelectric means and cooperating with said feeding mechanism for automatically feeding said material through said stitching mechanism in a forward direction, second photoelectric means supported by said machine for producing an output signal upon the appearance of a preselected portion of said material at said stitching mechanism, and means interconnecting said second photoelectric means and said reversing means for automatically actuating said reversing means in response to said output signal, to change the direction of feed of the material for a predetermined period of time, said circuit means thereafter continuing the automatic feeding of said material through said stitching mechanism in said forward direction.

11. In a sewing machine having a power source and a stitching mechanism operated by said power source, the combination comprising a reversible feeding mechanism driven by said power source for advancing material through said stitching mechanism, means interconnecting said power source and said feeding mechanism, reversing means for controlling said feeding mechanism to reverse the direction of feed of the material, first sensing means supported adjacent said stitching mechanism, circuit means interconecting said first sensing means and said feeding mechanism for automatically feeding said material through said stitching mechanism in a forward direction, second sensing means supported on the infeed side of said stitching mechanism, for producing an output signal upon the appearance of the trailing edge of said material thereat, and means connected to said second sensing means and responsive to said output signal for automatically actuating said reversing means, to reverse the direction of feed of the material for a predetermined period of time, said circuit means thereafter continuing the automatic feeding of said material through said stitching mechanism in said forward direction.

12. In a sewing machine having a power source and a stitching mechanism operated by said power source, the combination comprising a reversible feeding mechanism driven by said power source for advancing material through said stitching mechanism, means interconnecting said power source and said feeding mechanism, reversing means for controlling said feeding mechanism to reverse the direction of feed of the material, first photoelectric means supported adjacent said stitching mechanism, circuit means connected to said first photoelectric means and cooperating with said feeding mechanism for automatically feeding said material through said stitching mechanism in a forward direction, second photo electric means supported on the infeed side of said stitching mechanism for producing an output signal upon the appearance of the trailing edge of said material thereat, and means connected to said second photoelectric means and responsive to said output signal for automatically actuating said reversing means, to reverse the direction of feed of the material for a predetermined period of time, said circuit means thereafter continuing the automatic feeding of said material through said stitching mechanism in said forward direction and including means for automatically arresting said feeding mechanism as the trailing edge of said material leaves said stitching mechanism.

13. In a sewing machine having a power source and a stitching mechanism operated by said power source, the combination comprising a reversible feeding mechanism driven by said power source for advancing material through said stitching mechanism, means interconnecting said power source and said feeding mechanism, reversing means for controlling said feed-ing mechanism to reverse the direction of feed of the material, first photoelectric means supported by said machine and having a first light path which is interrupted as said material enters said stitching mechanism, the interruption of said first light path conditioning said machine for automatic operation, circuit means connected to said first photoelectric means and cooperating with said feeding mechanism for automatically feeding said material through said stitching mechanism in a forward direction, said circuit means including a switch controlled by the operator of the machine for initiating the automatic operation of said feeding mechanism at substantially any point during the advance of said material through said stitching mechanism, second photoelectric means supported by said machine and having a second light path which is completed as the trailing edge of said material reaches said stitching mechanism, and means connected to said second photoelectric means and responsive to the completion of said second light path for automatically actuating said reversing means, to reverse the direction of feed of the material for a predetermined period of time, said circuit means thereafter continuing the automatic feeding of said material through said stitching mechanism in said forward direction.

14. In a sewing machine of the character set forth in claim 13, said first and second photoelectric means being supported on said machine in spaced relationship With said stitching mechanism, and means including a plurality of light conducting members for transmitting light from said photoelectric means along portions of said light paths to said stitching mechanism.

15. In a sewing machine having a power source and a stitching mechanism operated by said power source, the combination comprising a reversible feeding mechanism driven by said power source for advancing material through said stitching mechanism, clutch means interconnecting said power source and said feeding mechanism, manually operable means, connections between said manually operable means and said clutch means for engaging and disengaging the same, reversing means for controlling said feeding mechanism to reverse the direction of feed of the material, first photoelectric means supported adjacent said stitching mechanism and having a first light path which is interrupted as said material enters said stitching mechanism, the interruption of said first light path conditioning said machine for automatic operation, circuit means connected to said first photoelectric means for maintaining said clutch means in a continuously engaged condition and for interrupting the connections between said clutch means and said manually operable means, to automatically feed said material in a forward direction independently of said manually operable means, second photoelectric means supported adjacent said stitching mechanism and having a second light path which is completed as the trailing edge of said material reaches said stitching mechanism, and means connected to said second photoelectric means and responsive to the completion of said second light path for automatically actuating said reversing means, to reverse the direction of feed of the material for a predetermined period of time, said circuit means thereafter continuing the automatic feeding of said material through said stitching mechanism in said forward direction.

16. In a sewing machine having a power source and a stitching mechanism operated by said power source, the combination comprising a reversible feeding mechanism driven by said power source for advancing material through said stitching mechanism, clutch means interconnecting said power source and said feeding mechanism, first manually operable means, connections between said first manually operable means and said clutch means for engaging and disengaging the same second manually operable means for controlling said feeding mechanism to reverse the direction of feed of the material, first photoelectric means supported by said machine and having a first light path which is interrupted as said material enters said stitching mechanism, the interruption of said first light path conditioning said machine for automatic operation, circuit means connected to said first photoelectric means for maintaining said clutch means in a continuously engaged condition and for interrupting the conneclions between said clutch means and said first manually operable means, to automatically feed said material in a forward direction independently of said first manually operable means, second photoelectric means supported by said machine and having a second light path which is completed as the trailing edge of said material reaches said stitching mechanism, and means connected to said second photoelectric means and responsive to the completion of said second light path for automatically actuating said second manually operable means, to reverse the direction of feed of the material for a predetermined period of time, said circuit means thereafter continuing the automatic feeding of said material through said stitching mechanism in said forward direction.

17. In a sewing machine having a power source and a stitching mechanism operated by said power source, the combination comprising a reversible feeding mechanism driven by said power source for advancing material through said stitching mechanism, clutch means interconnecting said power source and said feeding mechanism, first manually operable means, connections between said first manually operable means and said clutch means for engaging and disengaging the same, second manually operable means for controlling said feeding mechanism to reverse the direction of feed of the material, first photoelectric means supported adjacent said stitching mechanism and having a first light path which is interrupted as the leading edge of said material is inserted into said stitching mechanism, the interruption of said first light path conditioning said machine for automatic operation, circuit means connected to said first photoelectric means for maintaining said clutch means in a continuously engaged condition and for interrupting the connections between said clutch means and said first manually operable means, to automatically feed said material in a forward direction independently of said first manually operable means, said circuit means including a switch controlled by the operator of the machine for initiating the automatic operation of said feeding mechanism at substantially any point during the advance of said material through said stitching mechanism, second photoelectric means supported on the infeed side of said stitching mechanism and having a second light path which is completed as the trailing edge of said material reaches said stitching mechanism, and means connected to said second photo electric means and responsive to the completion of said second light path for automatically actuating said second manually operable means, to reverse the direction of feed of the material for a predetermined period of time, said circuit means thereafter continuing the automatic feeding of said material through said stitching mechanism in said forward direction.

18. In a sewing machine having a power source and a stitching mechanism operated by said power source, the combination comprising a reversible feeding mechanism driven by said power source for advancing material through said stitching mechanism, clutch means interconnecting said power source and said feeding mechanism, first manually operable means, connections between said first manually operable means and said clutch means for engaging and disengaging the same, second manually operable means for controlling said feeding mechanism to reverse the direction of feed of the material, first photoelectric means supported adjacent the outfeed side of said stitching mechanism and having a first light path which is interrupted as the leading edge of said material is inserted into said stitching mechanism, the interruption of said first light path conditioning said machine for automatic operation, circuit means connected to said first photoelectric means for maintaining said clutch means in a continuously engaged condition and for simultaneously interrupting the connections between said clutch means and said first manually operable means, to automatically feed said material in a forward direction independently of said first manually operable means, said circuit means including a switch controlled by the operator of the machine for initiating the automatic operation of said feeding mechanism at substantially any point during the advance of said material through said stitching mechanism, second photoelectric means supported adjacent said stitching mechanism and having a second light path which is completed as the trailing edge of said material reaches said stitching mechanism, means connected to said second photoelectric means and responsive to the completion of said second light path for automatically actuating said second manually operable means, to reverse the direction of feed of the material for a predetermined period of time, said circuit means thereafter continuing the automatic feeding of said material through said stitching mechanism in said forward direction, and means controlled by said circuit means for disengaging said clutch means as the trailing edge of said material leaves said stitching mechanism and for simultaneously braking said feeding mechanism.

References Cited UNlTED STATES PATENTS 3,024,750 3/1962 Winz 112-203 3,080,836 3/1963 Clemens et al 112-2 X 2,052,896 9/1936 Roseman 1l2203 X RICHARD J. SCANLAN, In, Primary Examiner.