US2700948A

US2700948A - Buttonhole attachment

Info

Publication number: US2700948A
Application number: US301062A
Authority: US
Inventors: Robert W Burgess; Arnold E Gundersen; Connors John
Original assignee: Greist Manufacturing Co
Current assignee: Greist Manufacturing Co
Priority date: 1952-07-26
Filing date: 1952-07-26
Publication date: 1955-02-01
Anticipated expiration: 1972-02-01

Description

Feb. 1, 1955 R. w. BURGESS ET Al. 2,700,948

BUTTONHOLE ATTACHMENT Filed July 26, 1952 ATTORN EY5 United States Patent BUTTONHOLE ATTACHMENT Robert W. Burgess, Orange, Arnold E. Gundersen, New Haven, and John Connors, Hamden, Conn., assignors to The Greist Manufacturing Company, New Haven, Conn., a corporation of Connecticut Application July 26, 1952, Serial No. 301,062

3 Claims. (Cl. 112-77) This invention relates to a buttonhole attachment and more particularly to certain improvements in a buttonhole attachment like that shown in the Almquist Patent No. 2,482,607, granted September 20, 1949.

In the structure shown in this Almquist patent a feed blade is pivoted at the underside of the frame, the feed blade carrying a cloth-engaging foot to feed the cloth in which the buttonholes are to be made. Also pivoted to the frame is a lever which is oscillated by means of a cam driven from the usual fork arm. Upon the rear end of this lever is rotatably mounted a pinion, the teeth of which are in engagement with a rack of oblong shape so that when the pinion is rotated the teeth of the rack will be caused to move over those of the pinion, and as the rack is secured to the feed blade, the latter will be caused to move forwardly and rearwardly in an oblong path around the buttonhole, as will be understood from reference to the patent.

Provision is made for eifecting rotation of the pinion that is carried by the actuating lever when the lever is oscillated. This function is performed by a pawl or detent secured to the frame and adapted to engage the teeth of a ratchet wheel secured to the shaft upon which a pinion is mounted. That is, when the actuating lever is moved in one direction, the pawl will engage the teeth of the ratchet wheel and move it through the distance of one tooth space. When the lever is moved in the other direction, the pawl or detent will simply ride over the teeth of the ratchet wheel without rotating the latter. Thus, as the lever is oscillated in a to-and-fro movement, the ratchet wheel will be moved in a step-by-step manner and effect the proper feeding of the cloth in order to sew a stitch around the buttonhole.

This detent which serves to eifect rotation of the ratchet wheel has been found to be subject to considerable wear, and also in dropping from one tooth to another was found to be somewhat noisy in operation, and the invention of the present application is directed to an improvement in this detent or pawl so as to bring about improved operation of the device and to render the parts longer lasting and of greater service.

One object of the present invention is to provide a new and improved buttonhole attachment for sewing machines.

A further object of the invention is to provide a new and improved pawl mechanism to cooperate with a ratchet wheel of a buttonhole-sewing attachment in order that the ratchet wheel will be given a step-by-step movement during oscillation of the ratchet wheel toward and from the pawl.

A further object of the invention is to provide a buttonhole attachment having an actuating lever which is oscillated in a to-and-fro motion, having a ratchet wheel rotatably mounted on said lever to be moved therewith with a pawl mechanism mounted on the stationary frame of the device, which pawl mechanism is designed to engage the teeth of the ratchet wheel without undue noise and without undue wear upon the cooperating parts.

To these and other ends the invention consists in the novel features and combinations of parts to be hereinafter described and claimed.

In the accompanying drawings:

Fig. 1 is a top plan view of a sewing machine attachment embodying my invention;

Fig. 2 is a sectional view on line 2-2 of Fig. 1 with some parts being omitted for the sake of clearness;

2,700,948 Patented Feb. 1, 1955 gig. 3 is a detail perspective view of the pawl members; an

Fig. 4 is a perspective view of the spring which urges the pawl against the ratchet wheel.

To illustrate a preferred embodiment of our invention, we have shown a buttonhole attachment similar to that shown in the Almquist Patent No. 2,482,607. The attachment comprises a frame member 10 having mounted thereon a U-shaped standard 11 between the legs of which is rotatably mounted a cam wheel 12 having a wavy cam track 13.

Disposed at the underside of the frame 10 and pivoted thereto by the pivot 15 is a feed blade 16 carrying at its forward end a feeding foot 17. A rack member 18 of oblong shape is carried by the feed blade at the rear end thereof, this member having internal rack teeth 19, as shown more especially in Fig. l.

Pivoted at 20 upon the upper surface of the frame plate 10 is an actuating lever 21, this lever having at its forward end a cam follower 22 disposed in the cam track 13 so that when the cam member is rotated the lever 21 will be oscillated about its pivot 20.

Adjacent the rear end of the lever is rotatably mounted a shaft 24, which shaft carries upon its lower end a pinion 25, the teeth of which are in engagement with the rack teeth 19. It will be apparent that when the pinion 25 is rotated the rack teeth will be caused to move in engagement with the teeth of the pinion, thus moving the rack and the feed blade by which the rack is carried in an oblong path and in a forward and rear direction in order to sew around a buttonhole.

In order to rotate the pinion 25 a ratchet wheel 26 is secured upon the shaft 24, and provision is made for rotating this ratchet wheel in a step-by-step movement which will in turn rotate the pinion 25 in a step-by-step manner. Pivoted upon the stationary frame plate 10 is a pawl or detent shown in Fig. 3. This member has a base portion 27 which abuts flatly against a part of the frame plate 10 and is provided with an opening 28 to receive the pivot pin 29 so that the pawl has a pivotal movement about this pin. Adjacent the part 27 is a short vertically disposed portion 30, and upon the end of this portion is a horizontally disposed arm 31 having at its end an angularly bent finger 32 which engages the teeth of the ratchet wheel.

A wire spring shown in Fig. 4 is provided with an intermediate coil 33 received upon the pin 29. The rear end 34 of this spring is turned upon itself and bears against a flange 35 on the frame plate 10 so as to hold this end of the spring against upward movement. The other end 36 of this spring is attached to the detent by being inserted through an opening 37 in the portion 30 thereof.

It will be seen, therefore, that the spring will tend to move the detent in a clockwise direction about its pivot, as shown in Fig. l, and, therefore, tend to maintain the finger 32 in engagement with the teeth of the ratchet wheel 26. Also the spring will permit the detent to move away from the ratchet wheel when required so as to permit it to ride over the teeth of the latter as it is oscillated back and forth by the oscillations of the lever 21.

It will be noted that the detent need not be made of spring material although it is preferably made of sheet metal so that it may be manufactured by a stamping operation, and that the relatively light wire spring will serve to hold it in engagement with the ratchet wheel. The detent may be of hardened steel so that it will have longwearing qualities.

Also the finger 32 and the arm 31 may be made of considerable width so that the finger 32 will always engage the teeth of the ratchet wheel although the latter is relatively thin. No guiding means is necessary in order to maintain the engagement of the parts except, of course, as the detent is guided by the resting of the plate 27 flatly upon the upper surface of the portion of the frame plate 10.

It may also be noted that the detent will be locked against movement in a clockwise direction beyond that shown in Fig. 1. If the lever 21 is oscillated to move the ratchet wheel toward the detent, the latter cannot be moved toward the flange 35 due to the fact that its end is in engagement with the inclined surface of the teeth. That is, the detent is prevented by engagement with the ratchet wheel from swinging in a clockwise direction about its pivot 29, and hence the ratchet wheel must be rotated about its shaft. When this occurs the finger 32 of the detent will ride over the apex of a tooth of the ratchet wheel, the detent swinging about its pivot in a counter-clockwise direction. After it has ridden over the point of the tooth, it is then moved in a counter-clockwise direction into engagement with the inclined surface of the next tooth but limits any further movement of the detent.

While we have shown and described a preferred embodiment of our invention, it will be understood that it is not to be limited to all of the details shown, but is capable of modification and variation within the spirit of the invention and within the scope of the claims.

What we claim is:

1. In a buttonhole attachment for sewing machines, a frame, a lever pivoted on the frame for oscillation about its pivot, a shaft rotatably carried by the lever, a ratchet wheel secured to said shaft, means for effecting stepby-step actuation of said ratchet wheel during oscillation of the lever comprising a detent carried by the frame, said detent having a base resting flatly on the frame and pivoted thereto, a portion upstanding from the base and an arm carried by said upstanding portion, and a spring urging said detent in a direction to engage said arm with the ratchet wheel.

2. In a buttonhole attachment for sewing machines, a frame, a lever pivoted on the frame for oscillation about its pivot, a shaft rotatably carried by the lever,

a ratchet wheel secured to said shaft, means for effecting step-by-step actuation of said ratchet wheel during oscillation of the lever comprising a detent carried by the frame, said detent having a base resting flatly on the frame and pivoted thereto, a portion upstanding from the base and a horizontally extending arm carried by said upstanding portion, said arm having an angularly bent finger at one end thereof, and a spring urging said detent in a direction to engage said finger with the teeth of the ratchet wheel.

3. In a buttonhole attachment for sewing machines, a frame, a lever pivoted on the frame for oscillation about its pivot, a shaft rotatably carried by the lever, a ratchet wheel secured to said shaft, means for effecting stepby-step actuation of said ratchet wheel during oscillation of the lever comprising a detent carried by the frame, said detent having a base resting flatly on the frame and pivoted thereto, a portion upstanding from the base and a horizontally extending arm carried by said upstanding portion, said arm having an angularly bent finger at one end thereof, and a spring urging said detent in a direction to engage said finger with the teeth of the ratchet wheel, said finger being of greater width than the thickness of the ratchet wheel.

References Cited in the file of this patent UNITED STATES PATENTS Mowe Oct. 28, 1913