US2161141A - Presser mechanism for sewing machines - Google Patents

Description

June 6, 1939. A. H. DE VOE PRESSER MECHANISM FOR SEWING MACHINES Filed March 18, 1938 2 Sheets-Sheet 1 Gum/Mn,

C WLWeao: f7? Q "June 6, 1939. A. H DE VOE PRESSER MECHANISM FOR SEWING MACHINES Filed March 18, 1938 2 Sheets-SheetB Patented June 6, 1939 UNITED STATES PATENT OFFICE 2,161,141 r rnns'sea MECHANISM Fon SEWING MACHINES Application March 18, 1938, Serial No. 196,643

12 Claims. (01. 112-235) This invention relates to presser-mechanism for sewing machines and has for an object to provide a presser-m'echanism which will effectively cooperate with a four-motion feed-dog to feed the work at high operative speeds.

The usual four-motion feed-dog of a sewing machine is opposed by a presser-foot carried by a downwardly spring-pressed presser-bar. When the feed-dog rises through the slotted throatplate in the bed of the machine, it grips the work against the presser-foot and actually lifts the presser-foot and -bar a short distance during the work-feeding stroke of the feed-dog. At the end of it's work-feeding stroke the feed-dog drops below the top surface of the throat-plate and the presser-foot and -bar drop with the feeddog until the down-movement of the work is arrested by the throat-plate. The work then remains stationary while the feed-dog returns below the level of the throat-plate to its initial position ready to begin another feeding stroke. These engagements of the feed-dog with the work occur once for each stitch made by the machine, and the presser-bar and foot must rise and fall with the feed-dog once for each stitch.

As sewing machine speeds are pushed higher and higher, it becomes increasingly difficult to provide spring-pressed presser-mechanism which will follow the rapid up-and-down movements of the feed-dog and effectively cooperate with the feed-dogto feed the work. Increasing the spring-pressure upon the usual presser-bar has been tried but, at high speeds, this method of overcoming the difficulty puts too great a load upon the feeding mechanism and causes the feed-dog teeth to injure or cut the work.

According to the present improvement, in its preferred embodiment, the presser-foot is carried by a small and light Weight pivoted lever which is biased preferably by an adjustable vertically disposed cantilever spring housed in a cavity in the presser-barL The presser-bar may be lifted, as usual, for insertion and removal of work but remains stationary during the normal cooperative work-feeding movements of the feed-dog and presser-foot. A cantileverspring is found to be highly responsive to speed require- I ments and, according to the present improvement, a spring may be used which is stout enough to cause the light weight presser-foot and carrier lever to effectively follow the feed-dog at 1 speeds of the order of 8000 to 9000 stitches per minute, without loss of control of the work and without damaging work of fine texture, such as crepes and chifions.

In the accompanying drawings, Fig. 1 is an end elevation of the gooseneck of a sewing machine embodying the invention. Fig; 2 is a vertical section taken longitudinally of the presserbar shown in Fig. 1. Fig. 3 is a section on the 8 line 33, Fig. 2. Fig. 4 is a rear side elevation of the gooseneck. Fig. 5 is a top plan view of the head at the free end of the gooseneck. Fig. 6 is a, disassembled perspective view of the presserfoot and its carrier and parts associated there- 10 with, and Fig. '7 is a transverse sectional view. through the pressure-foot and teed-dog of the machine.

The sewing machine is constructed with a frame including the bed A-from which rises the stand- I ard B of the overhanging gooseneck C terminating at its free end in the head D. The machine has stitch-forming mechanism including the reciprocatory needle i and work-feeding mechaa nism including the four-motion feed-dog 2 which g rises and falls through the slotted throat-plate 3 and has feed-and-return movements above and below the level of the top surface of the throat-. plate.

Opposed to the feed-dog 2 is the presser-foot g; l which is pivoted on the pint carried by the lever-arm 6 having fixed thereto a pivot-pin l journaled in bearings in the arms 8, 8 of the bracket 9 clamped to the presser-bar l0 mounted for vertical sliding movement in a sleeve ll 30 fixed in the gooseneck head D. The presser-bar is pressed downwardly by the usual leaf spring l2 which bears upon a hardened pressure button I3 set in a socket in an offset portion ll of a split block l5 clamped upon the upper end of the presser-bar Ill.

,The presser-bar l0 and foot 4 may be lifted for insertion and removal of work, by operation of the usual hand-operated cam-lever It or treadle-operated'lever ll. When the presser- 40 foot is lowered to engage the work,'the downmotion of the presser-bar I0 is limited by engagement of the adjustable stop-screw l8 with the machine frame. This stop-screw I8 is threaded into the block l5 and is locked in adjusted position by the lock-nut Ill. The block l5 has a guide arm 20 integral therewith, which guide-arm works in a guideway 2| between the bracket-arm "C and a cheek-piece 22 screwed thereto. Thus, the presser-bar I0 is held from turning in its bearing sleeve II. The hand-operated cam-lever it engages the block 23 screwed to the block l5, while the treadle-controlled lever I'I engages the elongated head of the clamp-screw 24 by 55 which the split block i is clamped upon the presser-bar.

The lever-arm 6, which pivotally carries the presser-foot G, has formed integral therewith an upstanding arm 25 and a rearwardly extending arm 26. The upstanding arm 25 has in its rearward face a transverse groove 21 which receives the forward end of a strut or thrust-member 28 the notched rearward end of which engages the necked lower end-portion 29 of a cantilever spring 30 which is housed in a cavity or slot 3| in the presser-bar l0 and at its upper end is anchored in a. hole 32 formed in and axially of the presserbar above the slotted portion thereof.

The force of the spring 30 upon the strut 28 may be adjusted by manipulation of the adjusting screw 33 which is threaded into the presser-bar l0 and bears upon the spring 30 between the ends of the latter.

When the presser-bar I0 is lifted for insertion or removal of work, the motion of the lever-arms 6 and 25 imparted thereto by the strut 28 and spring 30 is limited by engagement of the crosspin 34 in the lever-arm 26 with the stop-shoulders 35 on the arms 8 of the bracket 9.

It will be seen that, by the means described, the movable parts 5, 28 of the presser-mechanism between the foot 4 and spring 30, may be made light in weight, so that they will quickly respond to the force of the spring 30 when the feed-dog 2 is falling below the throat-plate 3. Also the spring 30 is so supported and disposed of that it may be readily made strong enough to secure an ample working pressure of the presser-foot upon :the work and feed-dog.

.the bracket 9. There is no cramping tendency of any of the parts in such lifting movement.

By the means described, a spring of adequate force is brought to bear upon a vertically movable presser-foot with intervening moving parts of minimum inertia. Thus a presser-mechanism is provided which is responsive to a four-motion feed-dog working at higher speeds than have heretofore been successfully used.

The spring I2 is, of course, strong enough to hold the stop-screw 18 in continuous engagement with the frame-head D, during the feeding operation of the mechanism. In other words, the presser-bar it) remains stationary and does not vibrate vertically with the 'presser-foot 4 and feeddog 2.

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

1. In a presser-mechanism for sewing machines, a spring-pressed presser-bar, a stop to limit the down movement of the presser-bar under its spring, a lever pivotally carried by said presser-bar, a presser-foot carried by said lever, and a cantilever spring carried by said presserbar and acting upon said lever to bias the presserfoot toward the work.

2. In a presser-mechanism for sewing machines, a presser-bar, means to hold said presser bar stationary at a predetermined operative position, a presser-foot carried by and movable relative to said presser-bar, a cantilever spring carried by said presser-bar to bias the presser-fcot in one direction, and an adjusting screw carried by said presser-bar and bearing upon said spring between the ends of the latter.

3. In a presser-mechanism for sewing machines, a hollow presser-bar, a lever pivotally carried by said presser-bar,'a presser-foot carried by said lever, and a cantilever spring housed in .said presser-bar and arranged to bias said lever' in one direction relative to said presser-bar.

4. In a presser-mechanism for sewing machines, a presser-bar having a cavity extending longitudinally thereof, a lever pivotally carried by said bar at one end of said cavity, a presserfoot carried by said lever, a cantileverspring housed in said cavity and fixed at one end to said presser-bar, and an operative connection between the other end of said spring and said lever.

5. In a presser-mechanism for sewing machines, a presser-bar having a cavity extending longitudinally thereof, a lever pivotally carried by said bar at one end of said cavity, a presser-foot carried by said lever, acantilever spring housed in said cavity and fixed at one end to said presser bar, a connection between the other end of said spring and said lever, and means to adjust the Working force exerted by said spring upon said lever.

6. A hollow presser-bar, a tubular bearing in which said presser-bar is endwise slidably mounted, a prcsser-foot mounted on one end of said presser-bar for movement relative to said presser-bar, and a cantilever spring housed in and anchored at one end to said presser-bar and connected at its free end to move said presser-foot in one direction relative to said presser-bar.

7. In a sewing machine, a frame, a springpressed hollow presser-bar, means to lift the presser-bar, an adjustable stop to limit the down movement of said presser-bar, a lever pivotally carried by said presser-bar, a presser-foot carried by said lever, and a spring housed in said presser-bar and arranged to bias said lever in one direction relative to said presser-bar,

8. The combination with a four-motion feeddog, of an endwise slidable presser-bar and a presser-foot supported by and movable relative to said presser-bar and arranged to follow the rising and falling movements of said feed-dog independently of the presser-bar, and a spring to bias said foot downwardly upon the feed-dog during the falling movement of the latter, said spring reacting upon the presser-bar.

9. In a sewing machine, the combination with a frame, a four-motion feed-dog, and a presserbar, of a presser-foot supported by and having feed-dog-following movements relative to said presser-bar, a presser-foot spring for moving said presser-foot downwardly relative to' said presser-bar in response to the falling movement of said feed-dog, a presser-bar spring acting upon said presser-bar to move the latter toward said feed-dog, an adjustable stop engaging said frame to limit the movement of said presser-bar under the influence of said presser-bar spring, and means to lift the presser-bar for insertion and removal of work.

10. In a sewing machine, a frame including a bed, and a gooseneck terminating at its free end in a head, a presser-bar endwise slidably mounted in said head and formed with a cavity extending longitudinally thereof, a bracket fixed to the lower end of said presser-bar, a lever pivotally supported by said bracket, a presser-foot carried by said lever, a cantilever spring disposed in the cavity in said presser-bar and fixed at its upper end to said presser-bar, means at the lower end of said spring to transmit theforce thereof to said lever, and means carried by said presserbar to adjust the force of said spring.

12. The combination with a sewing machine frame having a bed and an overhanging bracketarm terminating in a head, of a presser-foot pivotally carried below the lower end of said head for rising and falling movements, a vertically disposed cantilever spring anchored at its upper end in said head and terminating at its lower free end adjacent said presser-foot, and an operative connection between the lower end of said spring and said presser-foot, whereby the rising move- 10 ment of the presser-foot is opposed by said spring.

ALBERT H. DE VOE.

Images