US1170025A - Presser-foot mechanism. - Google Patents

Description

L. E. TOPHAM.

PRESSER FOOT MECHANISM.

APPLICATION FILED MAY 10, I915.

Pafented Feb. 1, 1916.

3 SHEETSSHEET l.

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L. E. TOPHAM.

PRESSER FOOT MECHANISM.

APPLICATION FILED MAY 10, i915.

3 SHEETSSHEET 2.

Patented Feb. 1, 1916.

73 M f m L. E. TOPHAIVI.

PRESSER FOOT MECHANISM.

APPLICATION FILED MAY I0, 1915.

Patented Feb. 1, 1916.

3 SHEETS-SHEET 3.

' 1911, which LAURENCE E. TOPHAM, OF SWAMPSCOTT, MASSACHUSETTS, ASSIGNOR T0 UNITED SHOE MACHINERY COMPANY, NEW JERSEY.

0F PATERSON, NEW JERSEY, A CORPORATION OF PRESSER-FOOT MECHANISM.

1,1'70,025. Original application filed April 15, 1911,

Specification of Letters Patent.

Patented Feb. 1,1916.

Serial No. 621,286. Divided and this application filed May 10,

1915.; Serial No. 27,080.

To all whom it may concern:

Be it known that I, LAURENCE .E. TOPHAM, a citizen ofthe United States, residing at Swampscott, in the county of Essex and State of Massachusetts, have invented certain new and useful Improvements in Presser-Foot Mechanism; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make 'and/use the. same.

The present invention relates to presser foot mechanisms for sewing machines.

The object of the invention is to produce an improved presser foot mechanism particularly adapted for use in wax thread sewing machines employing a straight awl or needle but also embodying features capable of use advantageously in other types of sewing machines.

With this object in view the present invention consists in the constructions, combinations and arrangements of parts hereinafter described and claimed, the advantages of which will be obvious to .those skilled in the art from the following description.

The-present application is a division of application, Ser. No. 621,286, filed April 15, fully illustrates and describes a wax thread lock stitch sewing machine employing a straight awl and a straight hook' needle. In the drawings accompanying the present application only so much of this sewing machine is illustrated asis neces sary to enable the construction and mode of operation of the presser foot mechanism to be understood.

Referring to the drawings; Figure 1 is a view in front elevation of the. head of the machine; Fig. 2 is a vertical cross sectional view looking toward the rear showing particularly the adjusting mechanism for the presser foot spring and the mechanism for raising the presser foot from the foot treadle; Fig. 3 is a sectional plan view of the front portion of the head of the machine; and Fig. 4; is a detail view in section and side elevation of the parts at the upper end of the presser foot bar.

The presser foot 2 which cooperates with the work support to position the work is of usual construction, and is secured to the lower end of a presser bar 3. During the greater part of the cycle of operations of the work, however, the presser foot is raisedfrom the work so as to ofier no resistance to thev feeding movement. At the end of the feeding movement the presser foot is released and is again pressed against the work by said spring so that it has an opportunity to accommodate itself to the thickness of the stock. The presser foot remains pressed against the work until the beginning of the next feeding movement, when it is again lifted and the cycle of operations repeated. To enable the presser foot to be actuated as above described, the presser bar 3 is slidably mounted in brackets 4 and 5 on the machine frame. The presser bar is kept from turning in its sliding bearings by an arm 6 extending radially from it near its upper .end, the outer end of which arm is bifurcated to slidably engage a pin 7 proecting upwardly from the bracket 4. The lower end of the pin 7 is somewhat reduced to form a stud which is eccentric t0 the axis of the pin, and which is secured in a recess in the bracket 4: and clamped therein by a binder 8. The eccentric stud allows the pin 7 to be turned to compensate for wear between the pin and the bifurcated arm 6.

J The means for automatically raising the presser foot during each cycle of the stitch forming operations, includes a collar 9 slidably mounted upon the presser bar above the bracket'5. The collar 9 is provided with aforwardly extending ear or lug 10 which is bored to slide upon a pin 11 extending upwardly from the bracket 5. A helical compression spring 12 surrounding the pin 11 between the enlarged head of said pin and the lug 10 tends to normally press the sleeve 9 down in contact with the bracket 5 which thus acts as an abutment for the sleeve. The sleeve 9 is also provided with two lugs 13 which extend to the left, and between which is pivoted a lifting arm '14. When the free end of the arm 14 is presser bar 3 locking it in the sleeve 9, after which the presser bar 3 and sleeve 9 are lifted together during the continuation of the upward movement of the arm 14. The arm 14 is oscillated by an adjustable link 16 which connects the free end of the arm 14 with the end of an arm 17 which extends radially from the forward end of a.

slot in the side of the projecting end of the pin 20. Adjustment of the link 16 is had by removing the pin 20, moving the link out of engagement with the arm 17, and adjusting the screw and socket connection.

lVhen the arm 14 is in its lowered position, the sleeve 9 is pressed against the bracket 5 and the presser bar is free to adjust itself in accordance with the varying thickness of the work, so that when the arm 14 is afterward raised, it will grip the presser bar in whatever position the presser bar may be and lift the presser foot a predetermined distance from the surface of the work, regardless of the thickness of the work. A fixed amount of motion is communicated to the lifting arm 14, but the amount of lifting movement imparted to the presser bar 3. may be varied by and justing the inclination of the arm 14 by means of the adjustable link 16. By shortening the link 16, the amount of free movement of the lifting arm 14 before its cam shaped end 15 grips the presser bar will be increased, and the amount of lift 1mparted to the presser foot will be correspondingly decreased, since only the lifting movement of the arm 14 after the cam has gripped the presser bar is effective to raise the presser bar.

To enable the presser foot to be raised by the operator with the parts of the ma-. chine in any position which they assume during a cycle of operations, and particularly when the parts are in aposition to permit the removal or insertion of work, a treadle is provided and suitable connections whereby the presser foot may be raised at the will of the operator. To enable the presser foot to be thus raised the upper end of the presser bar is offset rearwardly to form an upwardly extending plate 31 which is provided with a horizontal forwardly extending ledge or shoulder 32. This shoulder 32 engages over the top of around finger 33 which extends rearwardly from the extreme end of a lifting arm 34 and which also bears against the flattened top of the main portion of the presser bar. The shoulder 32 and the fiat upper surface of the main portion of. the'presser bar thus form between them a laterally extending slot for the reception of the finger 33, so that when the arm 34 is lifted it will raise the presser bar. The arm 34 is formed on a sleeve 35 which is rotatably mounted upon a pin 36 which forms the forward bearing of a rock shaft 37. The rear end of the sleeve 35 has formed in it notches or recesses 38 in which are engaged forwardly projecting lugs 39 on the rock shaft 37. The lugs 39 are sufliciently smaller than the notches 38 to allow the sleeve 35 enough lost motion with relation to the rock shaft 37 so that the lever arm 34 is free to turn idly about its bearing on the pin 36 when the'presser bar is raised and lowered by the automatically operated lifting arm 14 during the normal operation of the machine.

The rock shaft 37 is turned to raise the arm 34 and presser bar'3 by means of a sliding bar or rod 40 secured to the laterally projecting arm 41 of a bell crank lever 42 rigidly mounted upon the rear end of the rock shaft. The sliding bar 40 is drawn downwardly by a. wire 43 running to a suitable treadle, not shown. In order to raise the treadle after it is released by the foot of the operator, a helical compression spring 44 is coiled about the rod 40 between the enlarged upper end of said rod and a plate 45 which is secured to the machine frame, and through which the bar 40 is slidably received. When the operator depresses the treadle, the wire 43 is drawn down, turning the rockshaft 37, which by means of the lug-and-notch connection 39 and 38 raises the arm 34 to'lift the presser bar. At the time when the needle and awl are out of the work and permitits easy removal the lifting arm 14 is in its downwardly .turned position and outof its gripping engagement with the presser bar so that the presser bar is free to slide up and down through the sleeve 9 which is held down against the bracket5 by the spring 12. The presser bar may, however, be raised by the treadle when the machine is at any position in its cycle of operation. If the treadle is depressed to raise the presser bar when it is gripped in. the sleeve 9 by the liftin arm 14, the presser bar 3 and sleeve 9 wil be lifted together until the arm 14, whose outer end is held by the link 16, is turned sufliciently to disengage its cam shaped end 15 from the bar, after which thesleeve 9 will be no longer raised, but the presser bar will be freely lifted through said sleeve. The downward pressure which extended laterally and bears down upon the finger 33 of the arm 34, and the rear end of which spring is'secured to the forward end of a sleeve 47 rotatably carried upon the rock shaft 37. Gear teeth 49 are cut in the rear portion of the sleeve l7 and mesh with a worm cut on a shaft 50 which is adapted to be manually turned by means of the handle 51 to adjust the tension of the spring 46 against the presser bar.

The invention having thus been described, what is claimed is 1. A sewing machine, having in combination, stitch forming devices, a work support, a presser foot, a slidably mounted presser bar, a pivotally mounted arm connected at its free end to the presser bar, a spring engaging the arm and acting to normally press the presser foot against the work, power driven means acting on the presser bar to raise the presser foot against the pressure exerted-by the arm once during each cycle of stitch forming operation, and manually operable means acting on the arm to raise the presser foot to permit the removal andv insertion of work.

2. A sewing machine, having in combination, stitch forming devices, a work support, a presser foot, a presser foot bar, a pivotally mounted arm connected at its free end to the presser foot bar, a shaft in alinement with the pivot of the'arm, a sleeve mounted on the shaft, a spring surrounding the shaft and having one end acting on the arm and the other end in engagement with the sleeve, and means for rotatably adjusting the sleeve to adjust the tension of the'spring.

3. A sewing machine, having in combination, stitch forming devices, a Work support, a presser foot, a presser foot bar, a pivotally mounted arm connected at its free end to the presser bar, a spring acting on the arm to normally press the presser foot against the work, power driven means acting on the presser bar to raise the presser foot against the pressure exerted by the arm once during each cycle of stitch-forming operations, a shaft in alinement with the pivot of the arm, means for rocking the shaft to raise the presser foot to permit the removal and insertion of work, and a lost motion connection between the arm and the shaft permitting movement of the presserfoot and arm without rocking the shaft.

4. A sewing machine, having in combination, stitch forming devices, a work support, a presser foot, a presser foot bar, a pivotally mounted arm connected at its free end to the presser foot bar, a shaft in alinement with the pivot of the arm, a sleeve mounted on the shaft, a spring coiled about the shaftand having one end acting on the arm and the other end in engagement with the sleeve, means for rotatably adjusting the sleeve to adjust the tension of the spring, means for rocking the shaftI to raise the presser foot to permit the removal and insertion of work, and a lost motion connection between the arm and the shaft permitting movement of the presser foot and arm without rocking the shaft.

5. A sewing machine, having in combination, stitch forming devices, a work support, a presser foot, a presser foot bar, a pivotally mounted arm'connected at its free end to the presser foot bar, a shaft in alinement with the pivot of the arm, a connection between the arm and the shaft, means for rocking the shaft to raise the presser foot to permit the removal and insertion of work, a sleeve mounted on the shaft, a spring coiled around the shaft and having one end acting on the arm and the other end in engagement with the sleeve, and means for rotatably adjusting the sleeve to adjust the tension of the spring.

LAURENCE E. TOPHAM.

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