US3721204A

US3721204A - Automatic needle positioning and presser foot lifting mechanism

Info

Publication number: US3721204A
Application number: US00199555A
Authority: US
Inventors: P Schaffer; B Hoverter; K Haas
Original assignee: Teledyne Inc
Current assignee: TDY Industries LLC
Priority date: 1971-11-17
Filing date: 1971-11-17
Publication date: 1973-03-20
Anticipated expiration: 1990-03-20

Abstract

Needle cooling apparatus, and needle and presser foot position controlling apparatus for use with sewing machines of the type having reciprocable needles and a raisable and lowerable presser foot, the needle cooling being effected by discharging cool air directly onto the needles while they are carrying out stitching with the air discharge being terminated as soon as stitching ceases. On-off operation of the air is provided by a control operated by the sewing treadle. Relative position control of the needle and presser foot is carried out automatically under control of the operator by means of a mode control, a needle positioner mechanism, a presser foot actuating device and a second control operated by the sewing treadle when the latter is heeled. During stitching the presser foot is always down, and when stitching is terminated, the needle is always down while the presser foot may remain down or move up as determined by the position of the mode control. Heeling of the treadle causes the needle to rise and causes the presser foot to rise if it were down, but if the presser foot had been up it is caused to descend until the needle rises and to thereafter rise. Release of the treadle from its heeled position causes the presser foot to descend.

Description

United States Patent 91 Schaffer et al.

1March 20, 1973 1 AUTOMATIC NEEDLE POSITIONING AND PRESSER FOOT LIFTING MECHANISM [75] Inventors: Philip 0. Schaffer, Mohnton; Bryce E. Hoverter, Reinholds; Kenneth C. Haas, Shillington, all of Pa.

[73] Assignee: Teledyne, Inc., Los Angeles, Calif.

[22] Filed: Nov. 17, 1971 [21] Appl. No.: 199,555

[52] U.S.Cl ..112/218 R, 112/219 A, 112/219 B, 9 112/239 [51] Int. Cl. ...D05b 69/22, D05b 71/04, D05b 29/02 [58] Field of Search...l 12/219 A, 219 B, 219 R, 239, 112/237, 220, 218 R [5 6] 7 References Cited UNITED STATES PATENTS 2,961,591 11/1960 Frankel et al ..112/219 A 3,667,410 6/1972 Bianchi ..112/219 B 3,245,369 4/1966 Myska ..112/219 B Primary Examiner-H. Hampton Hunter Attorney-Leon Edelson et a1.

[ 5 7 ABSTRACT Needle cooling apparatus, and needle and presser foot position controlling apparatus for use with sewing machines of the type having reciprocable needles and a raisable and lowerable presser foot, the needle cooling being effected by discharging cool air directly onto the needles while they are carrying out stitching with the air discharge being terminated as soon as stitching ceases. On-off operation of the air is provided by a control operated by the sewing treadle. Relative position control of the needle and presser foot is carried out automatically under control of the operator by means of a mode control, a needle positioner mechanism, a presser foot actuating device and a second control operated by the sewing treadle when the latter is heeled. During stitching the presser foot is always down, and when stitching is terminated, the needle is always down while the presser foot may remain down or move up as determined by the position of the mode control. Heeling of the treadle causes the needle to rise and causes the presser foot to rise if it were down, but if the presser foot had been up it is caused to descend until the needle rises and to thereafter rise. Release of the treadle from its heeled position causes the presser foot to descend.

l 1 Claims, 9 Drawing Figures PATENTEDMARZO I973 3. 721. 204

SHEET 16? 4 FIG.

3 F INVENTORS l 7 PHIL/P 0. scmrrzn am'cz' E. HOVE'RTER, .12 KENNETH c. HAAS iluewww ATTORNEYS PATENTEUMARZO 197s 3,721, 204

SHEET 2 BF 4 KENNETH C. HAAS 8) WM PM ATTORNEYS 22" INVENTORS PH/L/P O. SCHAFFER BRYCf E. HOVERTER, TR.

PATENTED M820 I975 SHEET 3 [IF 4 INVENTORS PH/L IP 0. SCHAFFEI? BRYCE E. HOVERTER, T 0 KENNETH c. HAAS A TTOR/VEYS PATENTEDMARZO I975 3,721, 204 SHEET u or 4 49 DROPOU DEL A Y a F/G.9

INVENTORS PHIL/P 0. SCI- AFTER BRYCE E. HOVERTER, IR,

KENNETH G. HAAS WM M A TTORNEYS AUTOMATIC NEEDLE POSITIONING AND PRESSER FOOT LIFTING MECHANISM This invention relates generally to sewing machines, and more particularly, relates to apparatus which may be either built integrally into a sewing machine or may be added to existing sewing machines as an attachment device for the purpose of cooling the stitching needle.

There are many sewing applications where the sewing needle becomes very hot during the course of a stitching operation due to the frictional engagement between the needle and the materials being stitched as the needle passes rapidly repetitively through the material. Particularly is this a problem in commercial and industrial stitching which utilize high speed sewing machines and machines which are used for stitching thick and dense materials, such as multiple plies of leather and plastic fabrics.

The apparatus according to the invention provides a control system for controlling the movements of the sewing needle and the presser foot with respect to one another in two different modes of operation, as well as controlling the activation of an air supply which is directed upon the stitching needle to effectively cool the needle. A cooling-air volume flow control is provided for selectively controlling the air volume to maintain it at a level sufficient to properly cool the needle while restricting the volume to a level which does not distort the stitching pattern by moving the thread from its normal running path.

As before stated, the control system provides two modes of operation which are selectable by the operator by movement of a mode selector switch to either the mode one or mode two position. In either mode, the apparatus is in one of three states as controlled by the particular position of a three position sewing machine treadle. The treadle positions are a center neutral to to which the treadle is normally biased, a toed position and a heeled position. When the treadle is toed by the operator, the presser foot is always down and the sewing machine is performing stitching. However, when the treadle is in either the center neutral or in its heeled position, the mechanical actions of the sewing machine apparatus are determined by the mode selection.

When the apparatus is in mode one, and the treadle is in the center or neutral position, the sewing machine needle is down and the presser foot is up. These conditions are desirable for adding an additional piece of material to be joined in fabricating an article. The additional piece of material can thus be positioned precisely with respect to the sewing needle and the already stitched plies. Additionally, this mode is also useful in single needle machines for pivoting the material being stitched about the needle to retain the stitch alignment and stitch formation during a stitching operation.

In this same mode one, when the treadle is heeled by the operator, the presser foot first moves down to retain the stitched fabric, followed by the upward movement of the presser foot which thereby totally releases the stitched fabric from both the presser foot and the stitching needle and leaves it free on the sewing machine bed. This function permits easy removal of thick materials from engagement with the sewing machine needle because such materials would not normally remain in place when the sewing machine needle were raised for disengagement but would instead remain on and move upward with the needle.

In mode two then the sewing machine treadle is in its center or neutral position, both the needle and the presser foot are down. This mode is used during a stitching operation when it is necessary or desirable to realign' the plies being stitched before continuing, and it is important that the work previously stitched be held securely in the same position prior to the resumption of stitching. Additionally, this mode is very useful when an additional piece of material is being inserted between plies of the material already in the machine so that alignment and registry are maintainable.

' It is a primary object of the. invention to provide a novel sewing machine needle cooling apparatus including a control system for controlling movements of the sewing needle and presser foot in two different modes, and a selective activation of the cooling air supply.

It is another object of the invention to provide an apparatus as described which includes a selectively adjustable air volume flow control to provide proper cooling of the sewing machine needle while avoiding distortion of the sewing pattern which can occur if the thread is shifted from its normal running path.

It is a further object to provide a novel apparatus as described that is capable of construction as an auxiliary device which is functionally combinable with pre-existing sewing machine structures to provide such machines with the desired needle cooling and controlled positions of the needle and presser foot.

The foregoing and other objects of the invention will become clear from a reading of the following specification in conjunction with an examination of the appended drawings, wherein:

FIG. 1 is a fragmentary rear elevational view of a sewing machine with part of the apparatus according to the invention illustrated as installed thereto:

FIG. 2 is an end elevation of a sewing machine according to the invention as seen from the stitching end with both the presser foot and needles shown in the down position;

FIG. 3 is a front elevational view of the presser foot and the needles as would be seen when viewed along the line 33 of FIG. 2;

FIG. 4 is a perspective of the sewing machine needle and presser foot as would be seen when looking somewhat down and from the right front region of the showing of FIG. 3; i

FIG. 5 is a perspective similar to that of FIG. 4 but as would be seen when viewed looking forward from the right and to the rear of the structure shown in FIG. 3;

FIG. 6 is a front elevation similar to that of FIG. 3 but illustrating the controlled conditions where the needle is down and the presser foot is up;

FIG. 7 is a front elevational view similar to that of FIG. 6 but illustrating the conditions in which both the needle and presser foot structure are elevated;

FIG. 8 is a front elevational view similar to that of FIGS. 6 and 7 illustrating the condition of needle up and presser foot down; and

FIG. 9 is a schematic diagram of the control circuitry by means of which the apparatus according to the invention is caused to function in the desired manner.

In the several figures, like elements are designated by like reference characters.

Turning now to the drawings, consider first FIGS. 1 to 5 and particularly FIGS. 1 and 2 which show the components which are physically attached to the sewing machine for the purpose of providing a flow of cooling air to the sewing machine needle and for automatically actuating the sewing machine presser foot. For illustrative purposes, the sewing machine is illustrated as having a pair of needles 1] carried by a vertically reciprocable needle bar 12 in the normal and usual manner. Similarly, the presser foot is shown as being the type having a curved plate 13 and a knurled wheel 14 both of which are secured to and carried by a vertically shiftable presser foot bar 15. The presser foot bar 15 extends upward into the sewing head of the sewing machine 10 and is coupled to the normal mechanism for biasing the presser foot downward against the bed plate by means of the compression spring 16, and is also coupled to a presser foot manual lift mechanism including a lift arm 17 which extends outward through the rear of the sewing head and which can be manually raised and lowered by means of the finger lift cam 18 pivotable about the pivot 19. The foregoing parts associated with the needle and presser foot systems are all standard parts of sewing machines and are present in all types of machines in one form or another.

As best seen in FIG. 1, to the rear of the sewing machine 10 and toward the hand wheel end is fixedly secured a bracket 20 by machine screws 21. The bracket 20 carries a single acting air cylinder 22 within which is vertically reciprocable a piston which is connected outward through the cylinder head to a piston rod 23. The upper end of the piston rod 23 is connected through an adjustable linkage designated generally as 24 to one end of a crank arm 25 which runs longitudinally behind the sewing machine to a pivotal connection 26 which secures the crank arm 25 to the sewing machine. The crank arm 25 turns vertically downwardly at the pivot 26 and then again extends over toward the stitching head where it is fixedly connected to a laterally offset lift finger 27 which extends just beneath the presser foot lift arm 17, all as best seen in FIGS. 1 and 2.

The arrangement of the air cylinder 22 and its associated piston and piston rod 23 is such that when the air cylinder 22 is not pressurized, the piston rod 23 is in its upward position out of the cylinder and the lift finger 27 is consequently at its low point so that presser foot lift arm 17 is in its down position as is the presser foot itself. When the air cylinder 22 is pressurized from a source of compressed air through pneumatic line 28 and quick dump air valve 29, the air cylinder piston is driven downward within the cylinder and thereby pulls downward on the piston rod 23 causing the crank arm 25 to pivot about the pivot 26 causing the lift finger 27 to elevate the presser foot lift arm 17 and consequently to raise the presser foot. When the air pressure is released, the piston rises within the cylinder 22 at a rate determined by the dump rate regulator 30 to thereby permit the presser foot to descend but at a rate which seats the presser foot gently and avoids sharp impact thereof against the bed plate.

The air for cooling the sewing machine needles ll flows from the air source through pneumatic line 31 into and through the adjustable air flow control 32 to pneumatic line 33 which terminates at a discharge end 34 held in proper position by a bracket 35 carried by the presser foot structure. The air volume through the flow control valve 32 is adjusted by means of the knurled ring 36.

Understanding now the basic mechanical changes to a sewing machine which are represented by the apparatus just described, an understanding-of the operation of the apparatus will be best appreciated from an examination of the circuit diagram of FIG. 9 to which attention should now be directed. The schematic diagram of FIG. 9 encompasses two basic sections, one being that portion of the apparatus which is concerned with needle positioning, while the other portion of the apparatus is concerned with positioning the presser foot either up or down and with activating and deactivating the needle cooling air. Necessarily, there are of course interconnections between the two sections, and both sections utilize parts of the same power supply. The power supply includes the terminals 37 which are connectable to a power source of alternating current, step-down transformer 38 and full wave rectifier 39 together with the conductors which interconnect these elements to the source of power.

The needle positioner portion of the apparatus for down positioning of the needles 11 includes treadle switch 40, pole 41 and contact 42 of relay 43, brushes 44 and 45 and rings 46 and 47 of synchronizer device 48, relays K1 and K2, drop out delay device 49 and needle positioning motor 50. The needle positioner aspects of the control mechanism are essentially the same as those of the needle positioning mechanism previously illustrated and described in US. Pat. No. 2,961,591 assigned to the assignee of the present invention, a brief description of which now follows.

The synchronizer 48 includes a rotor which has a plurality of rings, of which ring 47 is completely conductive regardless of the rotated position of the synchronizer and in which others of the rings are conductive in the arcuate regions shown in heavy line while being nonconductive in the arcuate portions shown in lighter line. This ring assembly is concentrically mounted to the spindle shaft of the sewing machine'and rotates therewith while a brush holder which carries the brushes which engage the rings is mounted in fixed position with respect to the sewing machine so that the rings rotate past the brushes as the sewing machine spindle shaft rotates. Since one revolution of the spindle shaft corresponds exactly to one complete stitch forming cycle, the positions of the sewing machine needles always correspond to unique positions of the rotatable rings. Accordingly, the brushes of the synchronizer can be positioned so that when the needle is in particular positions, the brushes will be engaged with particular portions of the rings, as for example a conductive portion or a nonconductive portion.

The positioning motor 50 is of the direct current type and has its field winding and armature both energized for driving movement by the motor for positioning the sewing machine needle, and incorporates dynamic braking by having its armature shortcircuited while the motor is rotating with its field winding still energized. The control of the positioning motor is carried out by the relays K1 and K2 together with the dropout delay circuit 49.

When the sewing machine operator finishes a stitching sequence and releases the operating treadle the treadle assumes its center or neutral position, the switch 40 closes as illustrated in FIG. 9 to thereby establish a current flow path through pole 41 and contact 42 of relay 43 to synchronizer brush 44. If the sewing machine has stopped with the needles 11 in the desired down position then the brush 44 will be in contact with a nonconducting segment portion of the ring 46, also as shown. In this event, there can be no current flow from the brush 44 into the ring 46 so that the needle positioning motor cannot be energized and no change in the position of the needles 1 1 will occur.

If however the needles 1 1 have come to rest in a nondesired position, then the synchronizer brush 44 will be in contact with an electrically conductive portion of the ring 46 and current will flow from the power supply through the path previously traced to the brush 44, into ring 46 and then to center conducting ring 47 through the shorting link 51, thence outward through brush 45 to energize the relay K1. When relay Kl pulls in it also pulls in relay K2, energizes the dropout delay circuit 49, which typically may be a capacitor, and also removes a short circuit across the positioning motor armature so that the positioning motor when energized may drive the sewing machine and consequently also rotate the synchronizer rings. The pull-in of relay K2 energizes the field and armature windings of positioning motor 50.

Rotation of the synchronizer rings continues until brush 44 runs off of the conductive portion of ring 46 and onto a nonconductive portion which then interrupts the flow of current to relay Kl. When relay K1 drops out, it automatically applies a short circuit across the armature of positioning motor 50. However, the field winding of the motor 50 remains energized for a time because the dropout delay 49 temporarily maintains relay K2 in an energized state. Dynamic braking of the positioning motor 50 therefore occurs which stops the motor and consequently the sewing machine within the nonconductive interval of the ring 46 corresponding to positioning the sewing machine needles 11 in their down position as shown in FIGS. 2 through 6. Relay K2 thereafter drops out and deenergizes the positioning motor windings.

As before described, in the center or neutral position of the treadle, the sewing machine needles 11 are in the down position for both mode one and mode two, and the foregoing needle positioner description describes how this is accomplished. However, also for both mode one and mode two, when the treadle is heeled, among other things which occur the needles 11 are caused to rise to an up position by operation of the needle positioner. This up positioning of the needles is effected in the following manner.

When the treadle is heeled, heel switch 52 closes to thereby establish a current flow path from the power supply through the coil 53 of relay 43 and through blocking diode 54 to ground. Energization of relay coil 53 causes relay pole 41 to transfer from contact 42 to contact 55, and also causes relay pole 56 to transfer from Contact 57 to contact 58 to latch the relay even if the heel switch 52 is opened by release of heeling pressure on the treadle. With pole 41 now engaged with contact 55, current flows from the power supply through treadle switch 40, pole 41 and contact 55 to synchronizer brush 59, into synchronizer ring 60 to shorting link 51, thence to ring 47 and through brush 45 to relay Kl of the needle positioner. The positioning motor is then operated as before until brush 59 runs off of the conductive portion of ring 60. Since the nonconductive portions of

rings

46 and 60 are 180 out of phase, the sewing machine needles 11 will then be in their up position when positioning is terminated.

Understanding now how the needle positioner mechanism works to provide automatic down positioning of the sewing machine needles in either mode one or mode two when the sewing machine treadle is in its center or neutral position, and that heeling of the treadle always causes automatic positioning of the needles in the up position, the remainder of the diagram of FIG. 9 which is concerned with the raising and lowering of the presser foot and with the supply of cooling air to the needles will be readily understood. As shown in FIG. 9, the conditions shown are with power on, needle cooling air not flowing, sewing machine treadle in its neutral or center position in which the treadle switch 40 is closed and the treadle heel switch 52 is open, and the mode switch 61 in its mode one position, that is, where the needles are down and the presser foot is up as shown in the front elevational view of FIG. 6.

It should be noted that the treadle switch 40 is the master control switch in that needle positioning and presser foot control functions can only be carried out when the sewing machine treadle is in either its center neutral or heeled position since it is only in these positions that the switch 40 is closed. During normal stitching operations when the treadle is toed by the operator in the usual manner, treadle switch 40 is open which disables the needle positioning mechanism and the automatic presser foot lifting mechanism. Needle cooling air is also controlled by the treadle switch 40 in such manner that air is caused to .blow on the needles during stitching when treadle switch 40 is open, while the air is cut off when stitching is terminated and the treadle switch 40 is closed.

The needle cooling portion of the circuit shown in FIG. 9 includes the relay 62 and air controlling solenoid 63. When treadle switch 40 is closed as shown, current flows from the power supply through the treadle switch and energizes the coil 64 of relay 62 thereby causing the

relay poles

65 and 66 to engage the normally open contacts 67 and 68. Since the actuating coil 69 of air controlling solenoid 63 is connected to contacts 70 and 71 of relay 62, the actuating coil 69 cannot be energized from the alternating current supply source through

relay poles

65 and 66 so long as the coil 64 of relay 62 is energized. Consequently, the solenoid actuated air valve 72 is closed and no air can be transmitted from the air source 73 to pneumatic line 31, and the needle cooling air supply is thereby shut off.

When however stitching is commenced, the treadle switch 40 opens and thereby denergizes coil 64 of relay 62 causing the

relay poles

65 and 66 to transfer to contacts 70 and 71 and thereby energize the solenoid coil 69 which opens air valve 72 and connects pneumatic line 31 to the source of air 73. Needle cooling air is therefore directed at the sewing needles during the stitching operation. As soon as stitching has terminated, the treadle switch 40 again closes to thereby shut off the air supply in the manner just described until a subsequent stitching operation is initiated. It should be noted that this actuation and deactuation of the cooling air supply is controlled solely by the condition of the treadle switch 40, is independent of the condition of the mode switch 61, and is therefore independent of whether or not the machine is operating in mode one or mode two.

The remainder of the circuitry is involved in controlling the up or down position of the presser foot in mode one and in mode two and includes

relays

74, 75 and 76, blocking diodes 77 and 78, and air control solenoid 79. One end of the coil 80 of relay 74 and one end of coil 81 of relay 75 are commonly connected to the power supply through the treadle switch 40, while the opposite end of coil 80 is connected to the ungrounded end of heel switch 52, and the opposite end of coil 81 connects both to contact 57 of relay 43 and to the pole 82 of relay 74. Contact 83 of relay 74, which is associated with relay pole 82, is connected to the ground return of the power supply.

With the conditions as shown, coil 80 of relay 74 is not energized since the heel switch 52 is open, and coil 81 of relay 75 is energized by current flow through contact 57 and pole 56 of relay 43. Consequently,

poles

84 and 85 of relay 75 arepulled into engagement with

contacts

86 and 87 and thereby carry alternating current from the supply source to

poles

88 and 89 of relay 76. Since the sewing machines needles 11 are in their down position, current cannot flow through the opencircuited synchronizer rings and brushes, and coil 900i 330 presser foot lift air cylinder 22 and cause the presser foot to be in its raised position.

Summarizing the conditions shown in FIG. 9, the

treadle is in its neutral or center position so that no sewing is occuring, and the mode switch 61 is open so that the equipment is in mode one with the sewing needles down and the presser foot up. If it is desired to transfer the operation of the sewing machine to mode two in which the sewing needles remain down and the presser foot is also down, it is only necessary to close the mode switch 61. With the mode switch 61 closed, current now flows from the power supply through the closed treadle switch 40, through closed pole 41 and contact 42 of relay 43 and by-passing the open-circuited synchronizer brushes and rings by flowing through the now closed mode switch 61, through diode 77 and coil 90 of relay 76 to the power supply ground return. Energization of coil 90 of relay 76

causes poles

88 and 89 to transfer from contacts 91 and 92 to contacts 95 and 96, thereby open-circuiting and de-energizing coil 93 of air control solenoid 79. De-energization of the solenoid coil 93 allows the air valve 94 to drop out and disconnect pneumatic line 28 from the source of pressurized air 73, consequently depressurizing the presser foot lift air cylinder 22 and causing the presser foot to descent.

When it is now desired to initiate a stitching operation and the operator toes the sewing machine treadle, treadle switch 40 opens and de-energizes coil 64 of relay 62 to turn on the cooling air flow to the sewing machine needles, and also

de-energizes coils

81 and 90 90

permits poles

88 and 89 to re-transfer to contacts 91 I and 92 of air control solenoid 79 and would of course normally energize the coil, open the air valve 94 and cause the presser foot to rise. However, the de-energization of coil 81 of relay causes its

poles

84 and 85 to disengage from

contact

86 and 87 and transfer to contacts 97 and 98 and thereby disconnect the coil 93 from the source of alternating current, preventing energization of air control solenoid 93 so that the presser foot remains in its down position. The de-energization of relay coil 90 is delayed momentarily with respect to de-energization of relay coil 81 by discharges of capacitor 99 through the coil 90 across which it is shunted. This insures that the

relay poles

84 and 85 have been open-circuited before

relay poles

88 and 89 engage contacts 91 and 92.

When a stitching operation has been completed and the treadle has been returned to its center or neutral position, the sewing machine needles will stop in a down position under control of the needle positioning mechanism, and the presser foot will be either in a down or an up position as a function of whether the mode switch 61 is closed or open for selecting respec-' tively mode two or mode one operation.

As shown in FIG. 9, since mode switch 61 is open, the apparatus is in mode one condition, so that the presser foot is in its up position. If the treadle is now heeled, thereby closing treadle heel switch 52, as previously described the needle positioner mechanism is activated to move the needles 11 to their up position. At the same time, coil of relay 74 is energized thereby causing relay pole 82 to engage contact 83 .which maintains the coil 81 of relay 75 in an energized state even though pole 56 of relay 43 has disengaged from contact 57. With relay coil 81 remaining in its energized state,

relay poles

84 and 85 remain engaged with

contacts

86 and 87. However, while needle positioning was being carried out, current passed from the power supply through treadle switch 40, pole 41 and contact 55 of relay 43, brush 59 and ring 60 of synchronizer 48 to shorting link 51, thence into center conductive ring 47, brush 45 and out through blocking diode 78 to energize coil of relay 76. This disengages

relay poles

88 and 89 from contacts 91 and 92 and thereby de-energizes coil 93 of relay 79 to cause the presser foot to descend.

As soon as needle positioning has been completed, the current flow to coil 90 of relay 76 is terminated, and upon the discharge of capacitor 99 through the coil 90 to a point where hold-in current can no longer be maintained,

relay poles

88 and 89 retransfer and engage with contacts 91 and 92 of relay 79 to thereby energize relay coil 93 andcause the presser foot to then move up. From this sequence it will be understood that the presser foot at first descended to hold the work being stitched in place while the sewing needles were withdrawn upward out of the work, and thereafter the presser foot then again moved upward.

When the heel pressure is released on the treadle, heel switch 52 opens thereby de-energizing coil 80 of relay 74 and allowing pole 82 to disengage from contact 83. Since pole 56 of relay 43 remains engaged with contact 54 and disengaged from contact 57 there is no current return path for coil 81 of relay75, and this coil is thereby de-energized causing its'poles 84 and 85 to disengage from

contacts

86 and 87 thus de-energizing coil 93 of relay 79 and causing the presser foot to again move to its down position. The machine thus remains with the sewing needles in their up position and the presser foot in its down position until such time as the treadle is either again heeled or is toed. A second heeling of the treadle switch will merely cause the presser foot to again rise until the heeling pressure is released. When the treadle is toed, stitching is again carried out and upon termination thereof the machine will stop with the sewing needles in their down position by reason of the de-energization of coil 53 of relay 43 when the treadle switch 40 opened at the start of stitching.

If mode switch 61 had been closed so that the apparatus was in the mode two condition, then the sewing needles would be in their down position and the presser foot would also be down by virtue of the energization of relay coil 90 of relay 76 through the closed mode switch 61. When the treadle is now heeled, as before, the needle positioner immediately starts to operate and moves the needles from their down to their up position. The transfer of pole 41 to contact 55 of relay 43 when the latter is energized due to closure of the heel switch 52 does not cause de-energization of relay coil 90 of relay 76 even though the current passing through closed mode switch 61 has been interrupted, because current still flows through the operating synchronizer 48 and through blocking diode 78 to coil 90 for the same length of time that synchronizer current is flowing to needle positioning relay Kl. Consequently, relay coil 90 remains energized during the needle positioning so that the presser foot remains down until the needles have risen to their up position. Thereafter, the interruption of current flow through the synchronizer 48 causes relay coil 90 to become de-energized so that

relay poles

88 and 89 transfer to contacts 91 and 92, thereby energizing relay coil 93 and causing the presser foot to then rise. The presser foot remains up so long as the treadle is in its heeled position, but moves to the down position when the treadle is released and moves back to its centerneutral position thereby allowing switch 52 to open. The opening of switch 52, as before described, causes de-energization of relay coils '80 and 81 to thereby cause

relay poles

84 and 85 to disengage from

contacts

86 and 87 and de-energize relay coil 93 so that the presser foot again descends. A summary of the aforedescribed functional operation of the apparatus is Having now described our invention in connection with a particularly illustrated embodiment thereof, it will be apparent that variations and modifications of the invention may now occur from time to time to those normally skilled in the art without departing from the essential scope or spirit of our invention, and accordingly it is intended to claim the same broadly as well as specifically as indicated by the appended claims.

We claim:

1. Needle and presser foot position controlling apparatus for use with sewing machines of the type having a raisable and lowerable presser foot structure and a reciprocable needle, the needle being respectively driven for stitching and stopped by a main needle drive when the main drive is actuated and deactuated by an operator controlled stitching control, and including an auxiliary needle positioning drive mechanism operative to position the sewing machine needle in the down or up position independently of the main needle drive as determined by the sewing machine operator, comprising in combination.

a. actuatable presser foot shifting means engageable with the sewing machine presser foot lift mechanism effective when actuated to raise the presser foot and when deactuated to lower the presser foot,

. actuatable needle position control means coupled to the needle positioning drive mechanism effective when actuated to move the needle to its up position and when deactuated to move the needle to its down position,

. master control means coupled to the operator controlled stitching control and to said presser foot shifting means and said needle position control means, said master control means preventing actuation of said presser foot shifting means and needle position control means when the operator con trolled stitching control is operated to carry out stitching, and said master control means permitting actuation of said presser foot shifting means and needle position control means when the operator controlled stitching control is not carrying out stitching,

d. auxiliary control means coupled to said presser foot shifting means and needle position control means effective when actuated to actuate both said latter named means to thereby raise the presser foot and move the needle to its up position, and effective when thereafter deactuated to deactuate at least said presser foot shifting means and lower the presser foot.

2. Apparatus as described in claim 1 further including second auxiliary control means coupled to said actuatable needle position control means effective to maintain the latter actuated and the needle in its up position independently of the actuated or deactuated condition of said auxiliary control means once the latter has been actuated.

3. Apparatus as described in claim 1 further including additional auxiliary control means coupled to said presser ib ot shifting means effective when actuated to cause the latter to be deactuated and lower the presser foot.

4. Apparatus as described in claim 1 wherein said actuatable presser foot shifting means comprises a solenoid actuated linkage mechanism, wherein said master control means is an electrical switch which is opened during stitching and which is closed when stitching is terminated, and wherein said auxiliary control means is also an electrical switch which is rendered inoperative by said master control electrical switch when the latter is opened.

5. Apparatus as described in claim 2 wherein said second auxiliary control means is also coupled to said master control means and is rendered inoperative by the latter whenever the operator controlled stitching control is operated to carry out stitching.

6. Apparatus as described in claim 3 wherein said auxiliary control means is effective while in its actuated state to overide said additional auxiliary control means and raise the presser foot, after the needle has been moved to its up position by the needle positioning drive mechanism.

7. Apparatusas described in claim 3 wherein said additional auxiliary control means is also coupled to said master control means and is rendered inoperative by the latter whenever the operator controlled stitching control is operated to carry out stitching.

8. Apparatus as defined in claim 5 further including needle cooling apparatus, comprising in combination,

a. an air conduit having an inlet end and an open outlet end, said outlet end of said conduit being positionable to discharge air directly upon the sewing machine needle portion which is directly above the position of work being stitched,

b. an openable and closable air valve having an air inlet and an air outlet, said air conduit inlet end being coupled to said valve air outlet, and said valve air inlet including means for coupling to a source of pressurized air,

c. selectively operable air control means coupled to said air valve for opening and closing the latter, said air control means being coupled to and controlled by the sewing machine stitching control so that said air control means opens said air valve to discharge air upon the sewing needle when the stitching control actuates the sewing machine neer dle drive and closes said air valve to terminate air discharge when the stitching control deactuates the sewing machine needle drive.

9. Apparatus as described in claim 8 wherein the sewing machine has a presser foot, and said air conduit outlet end is secured to and moves with the sewing machine presser foot.

10. Apparatus as described in claim 8 further including adjustable air flow control means in the air flow line by means of which the volumetric air discharge upon the sewing machine needle may be regulated.

11. Apparatus as described in claim 8 wherein the sewing machine stitching control is an operator controlled treadle, wherein said air valve is a solenoid controlled valve, and wherein said air control means is an electrical switch openable and closeable in accordance with the stitching and nonstitching positions of the operator controlled treadle.

Claims

1. Needle and presser foot position controlling apparatus for use with sewing machines of the type having a raisable and lowerable presser foot structure and a reciprocable needle, the needle being respectively driven for stitching and stopped by a main needle drive when the main drive is actuated and deactuated by an operator controlled stitching control, and including an auxiliary needle positioning drive mechanism operative to position the sewing machine needle in the down or up position independently of the main needle drive as determined by the sewing machine operator, comprising in combination. a. actuatable presser foot shifting means engageable with the sewing machine presser foot lift mechanism effective when actuated to raise the presser foot and when deactuated to lower the presser foot, b. actuatable needle position control means coupled to the needle positioning drive mechanism effective when actuated to move the needle to its up position and when deactuated to move the needle to its down position, c. master control means coupled to the operator controlled stitching control and to said presser foot shifting means and said needle position control means, said master control means preventing actuation of said presser foot shifting means and needle position control means when the operator controlled stitching control is operated to carry out stitching, and said master control means permitting actuation of said presser foot shifting means and needle position control means when the operator controlled stitching control is not carrying out stitching, d. auxiliary control means coupled to said presser foot shifting means and needle position control means effective when actuated to actuate both said latter named means to thereby raise the presser foot and move the needle to its up position, and effective when thereafter deactuated to deactuate at least said presser foot shifting means and lower the presser foot.

3. Apparatus as described in claim 1 further including additional auxiliary control means coupled to said presser foot shifting means effective when actuated to cause the latter to be deactuated and lower the presser foot.

7. Apparatus as described in claim 3 wherein said additional auxiliary control means is also coupled to said master control means and is rendered inoperative by the latter whenever the operator controlled stitching control is operated to carry out stitching.

8. Apparatus as defined in claim 5 further including needle coOling apparatus, comprising in combination, a. an air conduit having an inlet end and an open outlet end, said outlet end of said conduit being positionable to discharge air directly upon the sewing machine needle portion which is directly above the position of work being stitched, b. an openable and closable air valve having an air inlet and an air outlet, said air conduit inlet end being coupled to said valve air outlet, and said valve air inlet including means for coupling to a source of pressurized air, c. selectively operable air control means coupled to said air valve for opening and closing the latter, said air control means being coupled to and controlled by the sewing machine stitching control so that said air control means opens said air valve to discharge air upon the sewing needle when the stitching control actuates the sewing machine needle drive and closes said air valve to terminate air discharge when the stitching control deactuates the sewing machine needle drive.