US2934030A

US2934030A - Operation control means for mechanism actuating levers of sewing machines

Info

Publication number: US2934030A
Application number: US750463A
Authority: US
Inventors: John A Herr
Original assignee: Singer Co
Current assignee: Singer Co
Priority date: 1958-07-23
Filing date: 1958-07-23
Publication date: 1960-04-26
Anticipated expiration: 1977-04-26
Also published as: DE1183772B; FR1230380A; GB918436A

Description

April 26, 1960 J. A. HERR 2,934,030

- OPERATION CONTROL MEANS FOR MECHANISM ACTUATING LEVERS OF sswmc MACHINES Filed July 23. 1958 2 Sheets-Sheet l u L l INVENTOR.

John A. Herr 3 BY Fig.3. W

ATTORNEY April 26, 1960 J. A. HERR 2,934,030

OPERATION CONTROL MEANS FOR MECHANISM ACTUATING LEVI-IRS 0F SEWING MACHINES Filed July 25. 1958 2 Sheets-Sheet 2 INVENTOR.

John A. Herr AT TORNE Y United States Patent F OPERATION CONTROL MEANS FOR lVIECHANISM ACTUATING LEVERS OF SEWING MACHINES John A. Herr, Garwood, N.J., assignor to The Singer Manufacturing Company, Elizabeth, N.J., a corporatron of New Jersey Application July 23, 1958, Serial No. 750,463

7 Claims. (Cl. 112-220) This invention relates to sewing machines having mechanism-actuating levers for starting, raising a work clamp, operating a cutter and similar functions. More particularly, this invention relates to means for applying relatively constant operating forces to such levers wherein the actual forces may be supplied by the same motor which drives the sewing machine and are applied responsively to either automatic or operator-actuated means requiring a minimum effort.

It is a primary object of this invention to provide simple and effective means for moving the mechanismactuating levers of a sewing machine, which means may derive its entire moving power from the electric motor driving the sewing machine or from an auxiliary motor.

It is a further object of this invention to provide operation control means for the mechanism-actuating levers of sewing machines which means shall apply substantially constant working forces to said levers responsively to switch closure requiring a minimum effort on the part of the operator or in response to simple automatic control means.

With the above and other objects in View, as will hereinafter appear, the invention comprises the devices, combinations and arrangements of parts hereinafter set forth and illustrated in the accompanying drawings of a preferred embodiment of the invention, from which the several features of the invention, and the advantages attained thereby, will be readily understood by those skilled in the art.

In the drawings:

' Fig. 1 is a front elevation of a device embodying the invention with the supporting table structure in section. I Fig. 2 is a side elevation, partly in section, of the device looking in the direction of the arrows 2-2 of Fig. l.

Fig. 3 is a schematic diagram showing electrical connections for the device of Figs. 1 and 2.

Referring to Fig. 1, 1t} denotes a table-top, through an aperture 11 of which extends a belt 12 for driving a sewing machine (not shown) mounted on the table-top 10. A motor 13 is hung from supports 14 secured to the underside of the table-top as seen best in Fig. 2, and carries an output shaft 15 to which is secured a pinion 16 and a pulley 17 for driving the belt 12.

'Secured to the motor 13 at the ends thereof are parallel plates 18-18 which serve as supports for many of the elements to be described. A plate 19 secured transversely to plates 18-18 provides a platform on which are mounted conventional A.C. solenoids 20 and 21 having

movable armatures

22 and 23, respectively.

Journaled in

bearings

24 and 25 secured to the plates 18-18 is a shaft 26 having a long splined portion 27. A-large gear 28 in mesh with the pinion 16 is frictionally coupled to the shaft 26 by friction washers 29-29 heldv resiliently by means of a spring 30 between a hub member 31 fast on the shaft 26 and a free washer 32, as seen 2,934,030 Patented Apr. 26, 1960 best in Fig. l. The foregoing structure constitutes a simple friction clutch which may be adjusted by taking up on nuts 33-33 to transmit torque from the pinion 16 to the shaft 26 up to a maximum set limit, after which slippage occurs.

A shaft 34, journaled in the plates 18-18, carries a slide block 35 slotted to receive a rack36 which is thus constrained to slide endwise within the block and/or to be turned with it about the axis of the shaft 34. A lever arm 37 secured to the shaft 34 is engaged by a leaf spring 33 held in a split stud 39 to bias the shaft 34 and hence the block 35 in a direction normally to urge the rack 36 out of engagement with the splined portion 27 of the.

shaft 26. The stud 39 is secured to the plate 18 and adjustment of the biasing force is made by manipulation of nut 40.

A pivot rod 41 secured to the plates 18-18 forms the axis about which swings a lever 42 pivotally connected to a link 43 which, in turn, is pivotally connected to the armature 22. Secured to the lever 42 by means of screw 44 and nut 45 is a channel shaped guide-piece 46 which receives the rack 36 as seen best in Fig. 2. The free end of the screw 44 is reduced and hardened to form a wear finger 47 in relatively slidable contact with the rack 36. in the position shown in Fig. 2, the armature 22 of energized solenoid 20 is closed so that the finger 47 presses the rack 36 into driving engagement with the splined portion 27 of shaft 26. As shown, the rack 36 has been driven to its lowermost position by the shaft 26, and a stop-pin 48 rests against the slide block 35, the shaft 26 is thus stopped and the friction clutch is slipping.- If now the solenoid 20 were to be deenergized, the spring 38 would urge the slide block 35 to pivot about the axis of the shaft 34 and thereby disengage the rack 36 from the splined portion 27, whereupon the rack is released' for upward movement limited by a stop-pin 49 coming into contact with the bottom of the slide block 35. The lever 42 would be urged counterclockwise about the pivot rod 41, as viewed in Fig. 2, and the armature 22 would comes to rest against a stop bracket 50.

The upper end of the rack 36 is bifurcated to admit a hook 51 which is connected at one end to the stop-pin 48 and at the other end to a chain 52 which runs over

pulleys

53 and 54 to the upper side of the table-top 10,, where it may be connected, for example, to the clamplift lever of a group-stitch sewing machine of the type shown and described in the United States Patent No. 1,822,854, to which reference may be had for a complete understanding of the machine itself.

It is to be noted that the chain 52 can be connected to any mechanism-actuating lever which is biased to one position and requires a single pull for operation.

A customary arrangement for group-stitch sewing ma chines, as in the patent referred to above, is to have two levers, one for operating the work-clamp and the other for starting the machine. With this in mind, the present invention provides a second rack 55 slidable in a slideblock 56 secured to a shaft 57 journaled in the plates 18-18. A lever arm 58 secured to the shaft 57 is engaged by a leaf spring 59 held in a split stud 60 to bias the shaft 57 and hence the block 56 in a direction normally to urge the rack 55 out of engagement with the splined portion 27 of shaft 26. Adjustment of the biasing spring 59 is made by manipulation of nut 61. a

. A lever 62, pivotable about the pivot rod 41, is pivot ally connected to a link 63 which is, in turn connected;

pivotally to the armature 23. Secured to the lever 62 by means'of a screw 64 and a nut (not shown) is a channelshaped guide-piece 65 which receives the rack 55 ip the 3 same manner that the guide-piece 46 receives the rack 36, as shown in Fig. 2. The guide-piece 65 is not shown in Fig. 2 to avoid confusion of lines.

The armature 23 is shown in its open position against the stop 56 (as seen in Fig. 2) to which it is biased by the spring 59 acting through lever arm 58, shaft 57 block56, rack 55, lever 62 and link 63. This corresponds to .a position in which the rack 55 is out of engagement with the splined portion 27 of the shaft 26 and is thus in its uppermost position with a stop-pin 66 resting against the block 56 as viewed in Fig. l.

The upper end of the rank 55 is bifurcated to receive a cable 67 secured thereto by a stop-pin 68. The cable 67 7 runs over

pulleys

69 and 70 to the upper side of the tabletop where it may be connected, for example, to the starting lever of a group-stitch sewing machine of the type shown and describedin the United States Patent No. 1,822,854 referred to above.

'Fig. 3 shows how the solenoids 20 and 21 may be connected into a simple circuit for selectively controlling their energization. The solenoid 21 which controls the rack 55 for operating the starting lever of the sewing machine is connected through a switch 71 to a source S of electrical energy. The solenoid 20 which controls the rack 36 for operating the clamp-lift lever of the sewing machine is connected through a switch 72 in series with an interlock switch 73 to the source S. The

switches

71 and 72 may be treadle-operated switches or relay contacts in an automatic controlsystem. The switch 73 may be operated responsively to the position of a conventional stop-motion lever 74 found on group-stitch sewing machines of the type shown in theabove-mentioned United States patent. It will be noted that so long as the lever 74 is in the stopped position as shown, the switch 73 is closed and the clamp-lift lever can be actuated by closure of the switch 72. As soon, however,.as the lever 74 is pulled down tostart the sewing cycle, the switch 73opens and remains open throughout the running period of the machine, and solenoid 20 cannot be energized by closure of switch 72. This interlock function prevents the work clamp from being lifted accidentally while the machine is running. a

A further mechanical interlock is also provided by the structure of this invention which prevents accidental starting of the machine with the work clamp raised. This comes about by the fact that all lever-moving power is derived frorn the single common shaft 27. Thus, if the clamp is raised, it means that the rack 36 is in its lowermost position as shown, with the stop-pin 48 against the block 35. In this position the rack 36 engages the splined portion27 and acts to lock the shaft 26 against rotation.

'Thus, if the solenoid 21 were now energized by accidental closure of the switch 71, the rack 55 would bepushed into engagement with the-stationary shaft 26and no force could be-transmitted to the cable 67 and no starting would result.

While the present invention has been specifically described in connection with the starting and clamp-lift levers of sewing machines it is not to be construed as so limited but includes within its scope application to any of the mechanism-actuating levers of a sewing machine, as

set forth in the appended claims.

-Having thus set forth the nature ofthe invention, what I claim herein is:

, 1.--A control system for a sewing machine having mechanism-actuating levers comprising an electric motor connected for drivingsaid sewing machine, a speed reducer, a torque-limiting clutch, a pinion driven from said motor through said speed reducer and clutch, racks operatively'connected each to a respective one of said levers, said racks being slidably pivoted to permit selective driving engagement with said pinion, electric solenoidmeans for" each of said racks to move said rackintodriving engagement with the pinion, spring bias means'normally to hold the racks out of engagement with the pinion, and I means for effecting selective energization of the solenoids to overcome said bias means.

2. The combination with a sewing machine having mechanism-actuating levers, of control means comprising an electric motor for driving said sewing machine, a torque-limiting clutch, a pinion driven by said motor through said clutch, a rack connected to each of said mechanism-actuating levers, said racks each being mounted on a respective pivoted slide block which is normally spring biased to hold the rack out of mesh with said pinion and manually-controlled solenoid-actuated means for selectively moving each rack about said slideblock pivot into meshed engagement with, said pinion:to transmit substantially constant operating forces from said motor'to said levers.

3.'Apparatus for operating the mechanism-actuating levers of a sewing machine comprising in combination, an electric motor, a torque-limiting clutch, a single pinion driven by said motor through said clutch, a separate rack connected to each .of said mechanism-actuating levers,

each rack being slidable endwise through a slide block which is pivoted on a fixed axis, means actuated by solenoids for turning each of said slide blocks about said axis to bring the respective rack into driving engagement with said single pinion, biasing means for normally holding each of said racks out of engagement with said pinion, and manually selective switch means for energizing each of said solenoids.

4. A device for utilizing the driving motor of a sewing machine to supply the forces for operating the mechanism-actuating levers of the sewing machine, comprising a torque-limiting clutch, a pinion driven by said motor through said clutch, a separate rack operatively connected to each of said mechanism-actuating levers, each of said racks being slidable endwise but pivotable about an axis drivingly to engage the pinion, biasing means for normally holding said racks out of driving engagement with the pinion, and manually-selective solenoid-actuated means for overcoming said biasing means .to pivot a selected rack about said axis drivingly toengage said pinion'and operate a selected one of said levers.

' 5. A lever-actuating device for sewing machines comprising a rotating shaft, a torque-limiting clutch, a pinion driven by said shaft through said clutch, racks connected to respective levers to be actuated, separate means supporting each of said racks for endwise sliding through a block pivoted on a fixed axis, means forbiasing each of said blocks to an angular position in which each rack is held out of driving engagement with said pinion, means opposing said-biasing means actuated by solenoids for moving-each of said racks into driving engagement with said pinion, manually selective'switch means for energizing said solenoids, and limit stop means for limiting the'endwise travel of said racks.

6. Apparatus for operating the mechanism-actuating levers of'a sewing machine comprising, in combination, driving means, a torque-limiting means, a single pinion driven by said driving means through said torque-limiting means, a separate rack connected to each of said mechanism-actuating' levers, each rack being slidable endwise and pivotableabout a fixed axis, means actuated by solenoids for turning each of said racks about said axis into driving "engagement with said pinion, biasing means for normally holding eachof said racks laterally out of engagement with said pinion, manually selective means means, a separate rack connected to each of said mechanism-actuating levers, each rack being slidable endwise and movable into and out of driving engagement with said single pinion, means actuated by solenoids for moving each of said racks into driving engagement with each pinion, biasing means for normally holding each of said racks laterally out of engagement with said pinion and manually selective means for energizing said solenoids.

References Cited in the file of this patent UNITED STATES PATENTS McCann Apr. 2, 1940 Althens Oct. 2, 1945 Worthington Oct. 23, 1951 Sweet Nov. 1, 1955 Goldberg Feb. 4, 1958