US3039410A - Automatic clamp opening devices for sewing machines - Google Patents

Description

June 19, 1962 R. P. GRAHAM ETAL AUTOMATIC CLAMP OPENING DEVICES FOR SEWING MACHINES Filed Oct. 1, 1959 3 Sheets-Sheet 1 1' INVENTORS Richard P, Graham and I 1 I v, Joseph C. Huge WITNESS 1 {f By M M4; W M

gays A TORJVZI June 19, 1962 R. P. GRAHAM ETAL AUTOMATIC CLAMP OPENING DEVICES FOR SEWING MACHINES 5 Sheets-Sheet 2 Filed Oct. 1, 1959 INVENTORS Richard P. Graham and Joseph 6. Huge A TTORAEY WITIVE/SS n 1962 R. P. GRAHAM ETAL 3,039,410

AUTOMATIC CLAMP OPENING DEVICES FOR SEWING MACHINES F-iled Oct. 1,

3 Sheets-Sheet 3 IIIL INVENTOR$ Richard P. Graham and H T C. H W MW WITNESS nite AU'IDMATIC CLAMP OPENING DEVICES FOR SEWING MACHINES Richard P. Graham, Strattor'd, Conn, and Joseph C.

Hage, Huntington, N.Y., assignors to The Singer Manufacturing Company, Elizabeth, N.J., a corporation of New Jersey Filed Oct. 1, 1959, Ser. No. 843,705 7 Claims. (Cl. 112-67) This invention relates to devices'for automatically operating an appurtenance to a sewing machine. Although this invention will be described hereinbelow and illustrated as applied to a device for automatically opening and closing a sewing machine work clamp upon starting and stopping of the sewing machine, the device of this invention may be used as well for operating thread or work cutters, presser lifters, work loading, or work manipulating devices, i.e., any appurtenance to a sewing machine which is biased in one direction and requires for operation to be shifted in the opposite direction.

It is an object of this invention to provide a device which is operated by means of a solenoid to open the work clamp automatically when the sewing machine is stopped.

Another object of this invention is to provide a means for relieving the solenoid of the task of maintaining the work clamp in an opened position while the sewing machine is stopped. The solenoid will be used, therefore, only for a brief instant while the work clamp is being opened. Overheating of the solenoid windings is thus obviated, a lighter solenoid may be used, and an alternating current solenoid, which would be unsatisfactory if required for extended periods of time, may be used.

With the above and other objects and advantages in view as will hereinafter appear, this invention comprises the devices, combinations and arrangements of parts hereinafter described and illustrated in the accompanying drawings of a preferred embodiment in which:

FIG. 1 represents an elevational view of a work clamp opening device built in accordance with this invention applied beneatha sewing machine supporting table,

FIG. 2 represents an enlarged cross-sectional view of the starting rock shaft illustrating an interlock in the disengaged position of parts when the sewing machine is stopped and the work clamp may be opened,

FIG. 3 represents a view similar to FIG. 2 but with the interlock illustrated in the engaged position of parts when the sewing machine is operating and the work clamp opening mechanism is locked out of operation,

FIG. 4 represents an enlarged elevational view of the solenoid actuated work clamp opening mechanism in the position of parts illustrated in FIG. 1 in which the work clamp is being held open, and with portions of the framework of this device broken away to expose the operating mechanism,

FIG. 5 is a cross-sectional view taken substantially along line 5-5 of FIG. '4 illustrating the brake device in the engaged position which it occupies in the position of parts illustrated in FIG. 4 for holding the work clamp open,

FIG. 6 represents an enlarged elevational view of the clamp opening mechanism similar to that of FIG. 4 but in the position of parts in which the work clamp is closed,

FIG. 7 is across sectional view taken substantially along line 77 of FIG. 6 illustrating the brake device in the released position which it occupies in the position of parts illustrated in FIG. 6 for releasing the work clamp to closed position,

FIG. 8 represents an enlarged elevational view of the work clamp opening mechanism similar to that of FIGS. 4 and 6 but in the position of parts in which the solenoid i ice is activated and the work clamp opening movements are occurring,

FIG. 9 is an enlarged cross-sectional view taken substantially along line 9' 9' of FIG. 1, and

FIG. 10 is an enlarged cross-sectional view taken substantially along line 10-10 of FIG. 9.

Referring tothe drawings, FIG. 1 illustrates the clamp lifting device of this invention as applied beneath a table top 11 of a sewing machine supporting stand. Reference is made to the United States patent of Hale et al. No. 2,822,771, February 11, 1958, which discloses a cyclically operable sewing machine in conjunction with which the clamp lifting device of this invention is adapted to operate. An aperture 12 formed in the table top has brackets 13 secured at each side fitted with cushions 14 upon which the sewing machine of the Hale et a1. patent is adapted to rest. Included in FIG. 1 is the representation of a sewing machine starting lever 15 which corresponds to the starting lever indicated at 94 of the Hale et al. patent, and a work clamp opening lever 16 which corresponds to the work clam-p opening lever 100 of the Hale et a1. patent. In FIG. 1, the levers 15 and 16 have been turned at right'angles'to their actual position on the sewing machine in the interest of clarity.

It will be appreciated, with reference to the sewing machine disclosed in the above referenced Hale et al. patent, that'turning of the work clamp opening lever 16 in a clockwise direction as viewed in FIG. 1 of this specification opens the Work clamp in opposition to the conventional spring pressure biasing the clamp closed. A counterclockwise motion of the starting lever 15, as viewed in FIG. 1, will shift the sewing machine stop 'rnotion'mechanism into running position, and the starting movement into the stopped position.

Suspended beneath the brackets 13 is a drip pan 20 formed'at one side with hearing lugs 21 in which a sewing machine starting rock shaft 22 is journaled. Fast on the starting rock shaft 22 is an operator influenced rock arm 23 having a pull chain 24 whichmay be connected to a foot treadle or the like (not shown). Also fast on the starting rock shaft 22 is a rock arm 25 apertured to accommodate a pull cable 26 connected to the sewing machine starting lever 15, and a rock arm27 having a connection, as will be described hereinbelow, with the work clamp opening mechanism of this invention. The sewing machine is thus provided with a single operator influenced control means having an on and an off position for controlling the sewing machine operation.

A locking lever'3ti carried on a fulcrum pin 31 adjustable along a stud 32 depending beneath the table top 11, is formed with anenlarged portion 33 having an arcuate slot 34 embracing the starting rock shaft 22. At its free extremity, the locking lever 34} is formed with a lateral :finger 35 underlying the rock arm 25 and apertured to accommodate the pull cable 26. A spring 36 servesto bias the locking lever counterclockwise as'viewed in FIG. 1. As best illustrated in FIGS. 2 and 3, the enlarged portion 34 of the locking lever is formed with an intnrned car 37 which cooperates with a cam edge 38 formed on astop block 39 clamped onthe starting rock shaft 22. When the'sewing machine is in stopped posi tion, the starting lever 15 through the pull cable 26 will turn the locking lever against the action of the spring 36 into the position illustrated in FIGS. 1 and 2 in which theaear 37 is'elevated out of the patch of the stop block 39. The rock shaft 22, and the'rock arms 23, 25 and 27, are therefore, free for turning movement in a clockwise direction. When the rock shaft 22 is turned counterclockwise to start the sewing machine, however, and while the start lever is latched in the running position, the spring 36 will hold the locking lever in the position illustrated in FIG. 3 in which the car 37 engages the cam surface 38 of the block 39 and prevents return movement of the starting rock shaft 22 while the sewing machine is operating.

At the side opposite the bearing lugs 21, the drip pan is formed with bearing lugs 41 in which is journaled a Work clamp opening rock shaft 42. A rock arm 43 fast on the rock shaft 42 is apertured to accommodate a pull cable 44 connected to the sewing machine work clamp opening lever 16. Also fast on the rock shaft 42 is a rock arm 45 to which work clamp opening motions are imparted by the devices of this invention.

The automatic work clamp opening unit of this invention is supported on a bracket secured by screws 51 beneath the table top H. The bracket 50 includes a pair of spaced triangular supports 52 transversely between which is journaled a stud shaft 53 to which is secured a work clamp controlling member in the form of a swinging lever 54 biased in a counterclockwise direction as viewed in FIGS. 1, 4-, 6 and 8 by a spring 55 best illustrated in FIG. 9.

The swinging lever 54 is slotted as at 56 to accommodate a pin 57 carried by the armature S3 of a solenoid 59 secured by screws 60 to the bracket 50. The solenoid 59 is preferably of the type adapted to be actuated by an alternating current. When an operating current is supplied to the solenoid, the armature 58 and the pin 5'7 thereon are drawn upwardly toward the solenoid 59. The solenoid may be provided with a spring (not shown) to bias the armature downwardly when the operating current is discontinued.

Fast on the stud shaft 53, and thus in fixed angular relation with the swinging lever 54 thereon, is a rock arm which carries a lateral pin 66 disposed for engagement with the rock arm 45 on the work clamp opening rock shaft 42. Therefore, when the solenoid 59 is energized and the swinging lever 54 is lifted, the sewing machine work clamp will be opened; and when the solenoid is deenergized and the swinging lever 54 is permitted to return to a lower position, the sewing machine work clamp will be closed. The swinging lever 54 thus is connected between the solenoid armature and the appurtenance to be operated such as the work clamp in the preferred embodiment.

The free extremity of the swinging lever 54 is provided with a notch 76 defining a seat which bears against a cushioning pad 71 on the bracket 50 when the swinging lever occupies a lower position. The swinging lever is also formed with an arm 72 extending upwardly from the notch 76 and formed along the outer edge with a camming surface 73. The arm 72 is disposed in a vertical slot 74 formed in the bracket 50.

The solenoid 559 is controlled by a normally closed held open switch 80 carried on a bracket fill beneath the frame 50. The switch is under the influence of a depending arm 32 of a switch control member in the form of a lever 83 fulcrurned on a pin 84 carried in a bearing lug 85 on the bracket 50.

A depending finger 36 on the lever 83 is engaged by a cam lug 87 fast on a rock shaft 88 journaled in the bearing lug 85. Also fast on the rock shaft 88 is a rock arm 89 which is connected to the rock arm 27 on the sewing machine starting rock shaft by means of a rod 9%.

Thus when the sewing machine starting rock shaft 22 is turned to start the sewing machine the cam lug 87 will shaft the lever 83 to hold open the switch 80, and by virtue of the locking lever 30, the parts will be held in this position during the entire cycle of sewing machine operation during which, therefore, the work clamp cannot be opened. Upon stopping of the sewing machine and release of the rock shaft 22 and with it the rock arm 27, the cam lug 87 will be turned to carry the lever 83 and its depending arm 82 away from the switch permitting the switch to return to the normally closed position and actuating the work clamp opening solenoid 59 automatically to open the Work clamp when the sewing machine stops.

In order that the solenoid 59 will be deenergized immediately after the sewing machine work clamp has been opened and not used to hold the work clamp open, a cam follower finger is secured to the lever 83 and disposed extending through an opening 96 in the frame 50 and into the slot 74 therein in the path of the vertical arm 72 of the swinging lever 54. The camming surface 73 of the vertical arm 72 will act upon the follower finger 95 to turn the lever 83 and hold the switch in opened position when the swinging lever 54 is raised sufiiciently to open the sewing machine work clamp.

The sewing machine Work clamp is held open by a brake device which grips and holds the vertical arm 72 of the swinging lever 54 in the elevated clamp open position. The brake is provided by means of a cylin drical roller 190 which is disposed between one side of the vertical lever arm 72 and a wedge block 101 carried in a niche N2 in the bracket 50 opening onto the slot '74 for the vertical lever arm 72. A set screw 193 is provided for adjusting the position of the wedge block for optimum gripping action of the brake roller 1%. Referring particularly to FIG. 10, a retaining lever 104 for the brake roller is fulcrumed at on the bracket 50 and provided with an ear 1% overlying the roller 100. A coil spring 1G7 connected between the retaining lever 104 and the switch bracket 81 biases the lever 104 and thus the cylindrical roller 1% downwardly toward engaged position of the brake to provide for a quick responseof the brake.

It will be apparent from the foregoing that separate means are provided for deenergizing the solenoid 59. As illustrated in FIG. 4, the cam surface 73 on the vertical arm 72 of the swinging lever 54 acting on the cam follower finger 95 turns the lever 83 sufiiciently far to hold the switch 80 open immediately upon the work clamp reaching raised position. The second means involves the starting rock shaft 22 which by way of the rock arm 27, the rod 90, the rock arm 8%, and the cam lug 37 acting on the finger 86 can turn the lever 83 to hold the switch 80 open as illustrated in FIG. 6.

Comparison of FIGS. 4 and 6 will indicate that the operation of the cam lug 37, as illustrated in FIG. 6, turns the lever 83 more than does the operation of the cam surface '73 as illustrated in FIG. 4. This difference in position of the lever 83 is utilized by way of a brake release arm flit) carried on the fulcrum pin 34 and secured in selected position with respect to the lever 83 by a clamp screw 111 accommodated in an arcuate slot 112 in the lever 33. The brake release arm 11b is formed with a finger 113 extending through an opening 114 in the bracket 50 into the niche Hi2 beneath the brake roller 160. By means of the clamp screw in and arcuate slot 112, the brake release finger 113 may be adjusted to lift the roller 1% and thus to release the swinging lever 54 to close the work clamp when the starting rock shaft is turned to start the sewing machine but not when the solenoid is deenergized immediately after the clamp has been opened.

The operation of the clamp opening device of this in vention might best be understood with reference to the general View illustrated in FIG. 1. In FlG. 1, the parts are illustrated in the position occupied when the sewing machine is stopped between cycles. The work clamp of the sewing machine is opened having been opened by the solenoid 59 which solenoid has been deenergized by the action of the cam surface 73 on the follower finger 95. The work clamp is held open by the brake roller 1W.

Since the sewing machine is stopped and the starting lever 15 is released, the locking lever 30 is raised disengaging the ear 37 from the cam surface 33 such that the operator may at will depress the chain 24 to start the sewing machine.

When the chain 24 is depressed to start the sewing machine, the rock arm 27 and pull rod 90 will shift the rock arm 89 and the cam lug 87 to impart suflicient turning movement to the lever 83 as to cause the finger 113 of the brake release arm to release the brake roller 100. The swinging lever 54 in returning to the position illustrated in FIG. 4 will thus lower the sewing machine work clamp.

Return movement of the rod 90 and of the cam lug 87 will be prevented by the locking lever 30 and the inturned car 37 thereon engaging the cam surface 38 as illustrated in FIG. 3 during operation of the sewing machine and thus, the parts will remain as illustrated in FIG. 6 with the clamp closed during operation of the sewing machine.

When the sewing machine stops and the locking lever 30 is raised, the rock shaft 22, the rock arm 27', the rod '90, the rock arm 89 and the cam lug 87 will be moved to release the switch 80 as illustrated in FIG. 8. The switch 80 closes upon being released and energizes the solenoid such that opening of the work clamp immediately begins.

The final work clamp opening motion of the solenoid 59 on the swinging lever 54 causes the cam surface 73 to shift the follower finger 95 and thus the lever 83 to open the switch 80 and deenergize the solenoid 59, as illustrated in FIG. 4. The cycle of operation is thus completed and the parts are again in the position illustrated in FIG. 1 with the brake roller 100 holding the work clamp open.

Having thus set forth the nature of this invention what we claim herein is:

1. In a sewing machine having a frame, stitch forming mechanism carried in said frame, driving means for said stitch forming mechanism, shiftable operator influenced control means for rendering said driving means effective to operate said stitch forming mechanism, said operator influenced control means having a first position in which said driving means is effective and a second position in which said driving means is inetfectvie, an appurtenance to said stitch forming mechanism shiftably supported on said sewing machine frame, means biasing said appurtenance into a retracted position, and means for automatically shifting said appurtenance out of retracted position whenever said operator influenced control means occupies said second position, said means comprising a solenoid including a solenoid frame and an armature movable relatively to said solenoid frame upon electrical activation of said solenoid, means fixedly supporting said solenoid frame relatively to said sewing machine frame, means operatively connecting said armature to said sewing machine appurtenance to shift said appurtenance out of said retracted position upon electrical activation of said solenoid, switch means controlling the electrical activation of said solenoid, means associated with said operator influenced control means for closing said switch means when said control means occupies said second position, means operated by the relative movement of said armature with respect to said solenoid frame for opening said switch, brake means associated with said appurtenance to prevent movement thereof into retracted position, and brake releasing means associated with said operator influenced control means and effective upon movement of said operator influenced control means into said first position.

2. A power conrtol unit for operating a sewing machine appurtenance of the type which is spring biased into retracted position on a sewing machine having a frame, sewing instrumentalities on said frame, a drive mechanism for said sewing instrument-alities, and a single operator influenced control member for said drive mechanism having an on position in which said drive mechanism is effective and an off position in which said drive mechanism is ineffective, said power control unit comprising, a bracket adapted to be supported in fixed relation relatively to said sewing machine frame, a solenoid carried on said bracket and including an armature movable in one direction relatively to said bracket upon electrical activation of said solenoid, an appurtenance controlling member shiftably supported on said bracket and operatively connected to said solenoid armature and to said appurtenance to be operated, brake means effective between said bracket and said appurtenance controlling member to prevent retrograde movement of said appurtenance controlling member in a direction opposite that in which the appurtenance controlling member is shifted by said solenoid armature, switch means carried by said bracket for controlling the activation of said solenoid, a switch control member shiftably supported on said bracket, means for operativcly connecting said switch control member to the operator influenced control member for said sewing machine drive mechanism to close said solenoid switch means when said operator influenced control member occupies an off position, brake release means carried by said switch control member and efiective when said operator influenced control member occupies an on position, and means carried by said appurtenance controlling member and effective to open said solenoid switch means upon predetermined movement of said appurtenance controlling member by said solenoid.

3. A power control unit for operating a sewing machine appurtenance of the type which is biased into retracted position on a sewing machine having a frame, sewing instrumentalities on said frame, a drive mechanism for said sewing instrumentalities and a single operator influenced control member for said drive mechanism having an on position in which said drive mechanism is effective and an off position in which said drive mechanism is ineffective, said power control unit comprising, a bracket adapted to be supported in fixed relation relatively to said sewing machine frame, a solenoid carried on said bracket and including an armature movable in one direction relatively to said bracket upon electrical activation of said solenoid, an appurtenance controlling member shiftably supported on said bracket and operatively connected to said solenoid armature and to said appurtenance to be operated, brake means effective between said bracket and said appurtenance controlling member to prevent retrograde movement of said appurtenance controlling member in a direction opposite that in which the appurtenance controlling member is shifted by said solenoid armature, switch means carried by said bracket for controlling the activation of said solenoid, a switch control member, means for supporting said switch control member on said bracket for cooperation with said switch means to open and close the same, means for operatively connecting said switch control member to the operator influence-d control member for said sewing machine drive mechanism to close said solenoid switch means when said operator influenced control member occupies an off position, means for operatively connecting said switch control member to said appurtenance control member to open said solenoid switch means upon predetermined movement of said appurtenance controlling member by said solenoid, and brake release means carried by said switch control member and eifective when said operator influenced control member occupies an on position.

4. Mechanism for automatically controlling a solenoid which is carried on a sewing machine and operatively connected to open a biased closed work clamp or the like when activated, said mechanism comprising a solenoid, switch means connected electrically to said solenoid to control the activation thereof, brake means associated with said solenoid to prevent retrograde movement thereof after activation, means rendered effective by the operation of said solenoid for opening said switch means to deactivate said solenoid, a shiftable solenoid control member, operator influenced means for shifting said solenoid control member in opposite directions, means associated with said solenoid control member and effective upon movement thereof in one direction to close said switch means, and means associated with said solenoid control member and effective upon movement thereof in the opposite direction to release said brake means.

5. A power control unit for operating a sewing machine appurtenance of the type which is biased into retracted position on a sewing machine having a frame, sewing instrumentalities on said frame, a drive mechanism for said sewing instrumentalities, and a single operator influenced control member for said drive mechanism having an on position in which said drive mechanism is effective and an off position in which said drive mechanism is ineffective, said power control unit comprising, a bracket adapted to be supported in fixed relation relatively to said sewing frame, a solenoid carried on said bracket and including an armature movable in one direction relatively to said bracket upon electrical activation of said solenoid, an appurtenance controlling member shiftably supported on said bracket and operatively connected to said solenoid armature and to said appurtenance to be operated, brake means effective between said bracket and said appurtenance controlling member to prevent retrograde movement of said appurtenance controlling member in a direction opposite that in which the appurtenance controlling member is shifted by said solenoid armature, a single pole single throw switch of the normally closed held open variety carried by said bracket for controlling the activation of said solenoid, a switch control member, means for supporting said switch control member on said bracket for engagement with said switch to hold said switch open and for movement out of engagement with said switch to close the same, means for operatively connecting said switch control member to the operator influenced control member for said sewing machine drive mechanism to close said solenoid switch means when said operator infiuenced control member occupies an off position, means for operatively connecting said switch control member to said appurtenance control member to open said solenoid switch means upon predetermined movement of said appurtenance controlling member by said solenoid, and brake release means carried by said switch control member and effective when said operator influenced control member occupies an on position.

6. A power control unit for operating a sewing machine appurtenance of the type which is biased into retracted position on a sewing machine having a frame, sewing instrumentalities on said frame, a drive mechanism for said sewing instrumentalities, and a single operator influenced control member for said drive mechanism having an on position in which said drive mechanism is effective and an off position in which said drive mechanism is ineffective, said power control unit com-prising, a bracket adapted to be supported in fixed relation relatively to said sewing machine frame, a solenoid carried on said bracket and including an armature movable in one direction relatively to said bracket upon electrical activation of said solenoid, an appurtenance controlling lever pivotally supported on said bracket and operatively connected to said solenoid armature and to said appurtenance to be operated, brake means effective between said bracket and said appurtenance controlling lever to prevent retrograde movement of said appurtenance controlling lever in a direction opposite that in which the appurtenance controlling lever is shifted by said solenoid armature, switch means carried by said bracket for controlling the activation of said solenoid, a switch control lever, means for supporting said switch control lever on said bracket for cooperation with said switch means to open and close the same, means for operatively connecting said switch control lever to the operator influenced control member for said sewing machine drive mechanism to close said solenoid switch means when said operator influenced control member occupies an off position, a cam follower finger formed on said switch control lever, cam means carried by said appurtenance controlling lever and cooperating with said cam follower finger to open said solenoid switch means upon predetermined movement of said appurtenance controlling lever by said solenoid, and brake release means carried by said switch control lever and effective when said operator influenced control member occupies an on position.

7. A power control unit for operating a sewing machine appurtenance of the type which is biased into retracted position on a cyclic sewing machine having a frame, stitch forming instrumentalities on said frame, a drive mechanism for said stitch forming instrumentalities including a stop motion mechanism automatically effective to render said drive mechanism ineffective upon completion of a predetermined member of stitch forming operations, a single operator influenced control member shiftable in one direction to render said drive mechanism effective, and means associated with said sewing machine for automatically returning said operator influenced control member upon operation of said stop motion mechanism, said power control unit adapted to be supported in fixed relation relatively to said sewing machine frame, a solenoid carried on said bracket including an armature movable in one direction relatively to said bracket upon electrical activation of said solenoid, an appurtenance controlling lever pivotally supported on said bracket and operatively connected to said solenoid armature and to said appurtenance to be operated, brake means effective between said bracket and said appurtenance controlling lever to prevent retrograde movement of said appurtenance controlling lever in a direction opposite that in which the appurtenance controlling lever is shifted by said solenoid armature, switch means carried by said bracket for controlling the activation of said solenoid, a switch control lever, means for supporting said switch control lever on said bracket for cooperation with said switch means to open and close the same, means for operatively connecting said switch control lever to the operator influenced control member for said sewing machine drive mechanism to close said solenoid switch means when said operator influenced control member occupies an off position, a cam follower finger formed on said switch control lever, cam means carried by said appurtenance controlling lever and cooperating with said cam follower finger to open said solenoid switch means upon predetermined movement of said appurtenance controlling lever by said solenoid, and brake release means carried by said switch control lever and effective when said operator influenced control member occupies an on position.

References Cited in the file of this patent UNITED STATES PATENTS 2,195,890 McCann Apr. 2, 1940 2,758,556 Hopkins Aug. 14, 1956 2,764,112 Happe Sept. 25, 1956 2,882,847 Winz Apr. 21, 1959 FOREIGN PATENTS 955,920 Germany Ian. 10, 1957 1,019,537 Germany Nov. 14, 1957

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