US3583345A

US3583345A - Needle clamp for sewing machines

Info

Publication number: US3583345A
Application number: US837494A
Authority: US
Inventors: Edmund B Wilson; William F Caplan
Original assignee: Singer Co
Current assignee: SSMC Inc
Priority date: 1969-06-30
Filing date: 1969-06-30
Publication date: 1971-06-08
Anticipated expiration: 1988-06-08

Abstract

A needle clamp for a sewing machine is disclosed comprising a resilient needle gripping member and means for deforming the resilient member into an operative needle gripping condition.

Description

United States Patent inventors Appl. No. Filed Patented Assignee NEEDLE CLAMP FOR SEWING MACHINES Primary ExaminerRichard J. Scanlan, Jr. Attorneys-Marshall J. Breen, Chester A. Williams, Jr. and

Robert E. Smith sclaimsflnrawing Figs ABSTRACT: A needle clamp for a sewing machine is dis- U.S.Cl 112/226 Closed comprising a resilient needle gripping member and Int. Cl DOSb 55/02 means for deforming the resilient member into an operative Field of Search 112/226 nee e gripp ng co dition.

|9-- 5 57 i 23 gll E 5| I 15 2| g ill PATENTEUJUN SIB?! 3583345.

IN VEN'I'URS William E Caplan Edmund B.Wilsonlll fiyw e Kim,

nnmrv NEEDLE CLAMP FOR SEWING MACHINES SUMMARY OF THE INVENTION This invention relates to a clamping device for fastening a sewing needle to the needle bar of the sewing machine in proper relation to the loop taker.

Heretofore it has been necessary for a sewing machine operator to turn a needle clamp thumbscrew a plurality of revolutions in order to engage the needle shank when fastening a sewing needle in the needle clamp. During the course of turning the thumbscrew the operator may, on occasion. improperly hold the sewing needle in fastening position relatively to the thumbscrew and either drop the sewing needle or fail to internally seat the needle shank the full axial depth of the clamp bore.

Dropping the sewing needle is not only frustrating but may result in damage and serious impairment of the stitch forming instrumentalities should the needle penetrate the needle hole in the throat plate and become lodged in such a way as to possibly damage the loop taker mechanism. In addition, should the operator fail to internally seat the needle shank the full axial depth of the clamp bore, the operator upon attempting to sew may find that the needle thread loop thrown out by the sewing needle is'improperly aligned proximate the needle thread seizing beak of the loop taker, which misalignment will result in the skipping of stitches or in a complete failure to form stitches.

It is therefore an object of the present invention to provide a needle clamp which will minimize the aforementioned undesirable conditions by means of structure readily accessible for manipulation permitting a quick-fastening of the sewing needle to the needle bar.

It is another object to employ means for deforming a resilient needle gripping member which is constrained in a recess formed in the lower end ofthe needle bar, resulting in a structural redistribution of the resilient member in a manner to grip the shank of a needle inserted into the resilient member.

It is further object of the invention to provide a needle clamp which assures that the sewing needle can only be inserted in correct relation to the loop taker.

A further object of the invention is to provide a clamp which firmly supports the sewing needle.

DESCRIPTION OF THE DRAWINGS With the above and additional 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 a perspective view of the lower portion of the sewing head illustrating the present invention in its needlegripping position;

FIG. 2 represents an exploded perspective view illustrating the present invention;

FIG. 3 represents an enlarged elevational view illustrating the assembled form ofthe present invention;

FIG. 4 represents a vertical cross-sectional view of FIG. 3;

FIG. 5 represents a horizontal cross-sectional view taken substantially along line 5-5 in FIG. 4;

FIG. 6 represents an enlarged horizontal cross-sectional view taken through line 6-6 in FIG. 4; and

FIG. 7 represents a view illustrating the development of the slotted camming portion ofthe clamping band.

DETAILED DESCRIPTION OF THE INVENTION The present invention as shown in FIG. 1 is illustrated as embodied on a conventional sewing machine having a frame including a work-supporting bed 11, over which is supported a bracket arm (not shown) terminating in a sewing head 13. Slidably supported for vertical movement in the sewing head 13 is a spring depressed presser bar 15 carrying at its lower end a presser foot 17. Supported for endwise reciprocation in the sewing head 13 is a needle bar 19 carrying at its lower end a needle 21 by means ofa needle clamp 23.

The needle bar 19 is formed with an axial recess 25 in its lower end constraining a resilient needle gripping insert 27. The resilient insert 27 is semicylindrical in form including an axially disposed open channel 29 formed with a flat bottom wall 31 and a rounded sidewall 33, as shown in FIG. 6.

Also supported internally of the recess 25 is a rigid needle carrier 35 semicylindrical in form and including a key 37 radially projecting from its outer surface. The key 37 is adapted to coact with a key slot 39 formed in the lower end of the needle bar 19.

The needle carrier 35 is formed with an axially disposed open channel 41 having a flat sidewall 43 and a flat bottom wall 45 disposed at an acute angle relative to the sidewall 43, as shown in FIG. 6. The lower portion of the needle carrier is cylindrical and provides an abutment face 47 eomplimental in form to the resilient insert 27, which abutment face 47 axially bears against one end of the resilient insert 27 when the needle clamp is assembled.

The flat bottom wall 31 of the resilient insert 27 coacts with the flat bottom wall 45 of the needle carrier 35 to receive the slab side 49 of the needle 21, which structure cooperatively functions, together with the key 37 and keyslot 39, to assure the correct positioning of the sewing needle 21 relative to the loop taker (not shown).

A clamping band 51 formed with a cylindrical bore 53 rotatably embraces the lower end of the needle bar 19. The clamping hand 51 is formed with an inclined camming slot 55. Projecting through the camming slot is a screw pin 57 which is threaded into a tapped hole 58 in the needle bar. The pin 57 secures the clamping band SI on the needle bar with capacity for turning movement, and because of the inclination of the camming slot 55, the clamping band when turned counter clockwise as viewed in FIG. 1, will shift axially upward relatively to the needle bar. To provide for turning the clamping band the latter is provided with a thumb grip 59 which when in its needle secured position can additionally function as a driving element for the usual needle bar actuated attachment. As shown in FIG. 4, the bore 53 at the lower extremity is formed with an inwardly extending flange 60 in which a needle clearance aperture 62 is provided. The needle carrier 35 is supported on the flange 60 so that as the clamping band shifts upwardly when turned counterclockwise, the carrier 35 will also be shifted upwardly so as to compress the resilient insert 27.

In the operation of the preferred embodiment, the operator can insert a needle 21 through the axially formed clearance aperture 62 in the clamping band 51 in only one orientation, i.e., with the slab side 49 of the needle 21 in register with the mutually aligned

flat bottom walls

31 and 45 of the resilient insert 27 and needle carrier 35, respectively. The operator then turns the clamping band 51 by swinging the thumb grip 59, thus causing the clamping band 51, through the action of the camming slot 55 on the screw pin 57, to shift upwardlyalong the needle bar 19.

As the clamping band 51 moves upwardly, the flange 60 shifts the needle carrier 35 upwardly and the abutment face 47 of the needle carrier 35 axially bears against and compresses the resilient insert 27. The resultant deformation of the resilient insert 27 effects a progressive radial deformation of the channel 29 and therefore a radial gripping of the needle 21 by the resilient insert 27.

It will be understood that only a minimal angular displacement of the thumb grip 59 is necessary to change the resilient insert 27 from one of relaxed inoperative condition to one of operative needle gripping condition.

Inasmuch as sewing needles in various sizes are used, the camming slot 55 includes a plurality of transversely formed locking grooves 61-61 adapted to coact with the pin 57 to provide detent means for locking needles differing in shank diameter.

From the foregoing description it is apparent that, in principal, the needle clamp disclosed herein utilizes structure for deforming a resilient member from a relaxed inoperative condition into an operative needle gripping conditions It will be understood that the aforementioned disclosure is merely a description of a preferred embodiment for accommodating a progressive deformation ofa resilient needle gripping member and is not to be construed as limiting the spirit of this invention.

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

1. In a sewing machine having a frame, a needle bar supported in said frame for reciprocation in an endwise path, a needle clamp comprising a resilient needle gripping means, means associated with said needle bar for constraining said resilient needle gripping means, a clamping band rotatably embracing said needle bar, said clamping band formed with an inclined camming slot, means projecting from said needle bar and engaging said needle bar engaging feed camming slot to shift clamping band axially along said needle bar when said clamping band is turned, and support means carried on said clamping band for effecting progressive deformation of said resilient clamping means when said clamping band is turned relatively to said needle bar.

24 A needle clamp as set forth in claim wherein said needle bar includes a cavity in which said resilient needle gripping means is confined, said cavity being formed with a slotted keyway, said clamping band including a needle carrier formed with a key adapted to coact with said keyway, said needle carrier including a needle accommodation channel formed with a flat sidewall and a flat bottom wall disposed at an acute angle relative to said flat sidewall, said channel in said needle carrier terminating in abutment means for deforming said resilient needle gripping means, said resilient needle gripping means in engagement with said abutment means and formed with a needle accommodation channel having a flat bottom wall adapted to coact with said flat bottom wall of said needle carrier for receiving a flat-sided needle shank.

3. A needle clamp as set forth in claim 1 wherein said camming slot includes a plurality of locking grooves transversely formed therein adapted to coact with said projection means providing a detent for locking sewing needles having shanks differing in a diametral size.

Claims

2. A needle clamp as set forth in claim 1 wherein said needle bar includes a cavity in which said resilient needle gripping means is confined, said cavity being formed with a slotted keyway, said clamping band including a needle carrier formed with a key adapted to coact with said keyway, said needle carrier including a needle accommodation channel formed with a flat sidewall and a flat bottom wall disposed at an acute angle relative to said flat sidewall, said channel in said needle carrier terminating in abutment means for deforming said resilient needle gripping means, said resilient needle gripping means in engagement with said abutment means and formed with a needle accommodation channel having a flat bottom wall adapted to coact with said flat bottom wall of said needle carrier for receiving a flat-sided needle shank.