US2964001A

US2964001A - Belt drives for sewing machines

Info

Publication number: US2964001A
Application number: US745616A
Authority: US
Inventors: Francis L Walling; Stanley M Sliva
Original assignee: Singer Co
Current assignee: Singer Co
Priority date: 1958-06-30
Filing date: 1958-06-30
Publication date: 1960-12-13
Anticipated expiration: 1977-12-13
Also published as: GB870601A; DE1836893U

Description

Dec. 13, 19 F. L. WALLING ETAL 2,964,001

BELT DRIVES FOR SEWING MACHINES 2 Sheets-Sheet 2 Filed June 30, 1958 INVENTOR. Francis L. Walling and BY SIan/ey M. Sliva g 9 ATTORNEY Dec. 13, 1960 w 1 ETAL 2,964,001

BELT DRIVES FOR SEWING MACHINES Filed June 30, 1958 2 Sheets-Sheet 1 "W v 14mm? I mmm i i i a i s Francis L. Walling a d 39 4O 2 BY Stanley M. Silva XQQV AT TORNEY United States Patent Ofitice 2,964,001 Patented Dec. 13, 1960 BELT DRIVES FOR SEWING MACHINES Francis L. Walling and Stanley M. Sliva, Trumbull,

Conn, assignors to The Singer Manufacturing Company, Elizabeth, N.J., a corporation of New Jersey Filed June 30, 1958, Ser. No. 745,616

2 Claims. (Cl. 112220) This invention relates to sewing machines and, more particularly, to a novel belt drive between the arm shaft and bed shaft of a sewing machine.

It is an object of this invention to provide a belt drive between spaced shafts of a sewing machine in which the shafts will partake ,of turning movement in opposite directions of rotation.

In the conventional sewing machine construction, an arm shaft which drives the needle bar and the needle thread take-up and a bed shaft which drives the looptaker are interconnected for rotation in timed relation. The direction .of rotation of arm and bed shafts differs in the various sewing machines presently established in the trade. In the event that it is desired to employ a needle bar and take-up mechanism of one established sewing machine design, such as the link take-up mechanism as disclosed in the United States patent of Kaier, No. 2,206,285, July 2, 1940, in combination with a bed shaft and loop-taker mechanism of a different established and proven design, such as that disclosed in the United States patent of Parry, No. 2,314,513, March 23, 1943, the problem arises that the proper direction of rotation of the arm and bed shafts must be maintained.

The present invention provides a novel and effective construction by which opposite directions of rotation may be attained between the arm and bed shafts of a sewing machine where a timing belt is used to drivingly interconnect the shafts.

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 side elevational view of a sewing machine embodying the invention, with portions of the sewing machine frame illustrated in verticfl cross section,

Fig. 2 is an enlarged cross sectional view, taken substantially along line 2-2 of Fig. 1, showing the details of the idler pulley,

Fig. 3 is a vertical cross sectional view of the sewing machine standard taken substantially along line 3-3 of Fig. 1, illustrating the belt drive between the arm and bed shafts, and

Fig. 4 is a vertical cross sectional View of the upper portion of the bracket arm taken substantially along line 44 of Fig. 1, illustrating the arm shaft sprocket pulley and the idler pulleys.

Referring particularly to Fig. 1 of the drawings, the sewing machine frame comprises a bed 11 from which rises a hollow standard 12 supporting a bracket arm 13 which overhangs the bed.

Journaled for rotation in the bed is a bed shaft 14 to which is fixed an internal gear 15 which meshes with a pinion 16 carried on a short hook shaft 17 journaled in the bed. A conventional rotary hook 18 is fast on the hook shaft. This hook driving mechanism beneath the bed is conventional and is similar to that disclosed in the United States Parry Patent No. 2,314,513. The op- 2 eration of the rotary hook requires that the bed shaft 14 be rotated in a clockwise direction as viewed in Fig. 3 and as indicated by the arrow thereon.

Iournaled for rotation in the bracket arm and substantially parallel with the bed shaft 14 is an arm shaft 20 which has fast thereto a hand wheel pulley 21 by which power is transmitted to the sewing machine. Fixed on the arm shaft within the bracket arm is a counterbalance 22 which carries an offset crank pin 23. A needle thread take-up lever 24 fulcrumed in the bracket arm is actuated by means of a drive link 25 which embraces one portion of the crank pin 23. A needle bar drive link 26 embraces the offset portion of the crank pin 23 and is pivoted in turn to a needle bar 27 which is carried for endwise reciprocation in bushings 28 in the bracket arm and has secured at its lower extremity a needle 29 which cooperates with the rotary hook 18 in the formation of lock stitches. The needle and take-up driving mechanism in the bracket arm is conventional and is similar to that disclosed in the United States Kaier Patent No. 2,206,285. The operation of the needle bar and take-up actuating mechanism requires that the arm shaft 20 be rotated in a counterclockwise direction as viewed in Fig. 3 and as indicated by the arrow thereon.

The belt connection by which the arm and bed shafts are drivingly interconnected for rotation in opposite directions of rotation comprises a continuous belt 31 to which is secured evenly spaced lugs or clips 32 which extend on both the inside and the outside of the belt. The belt illustrated in the drawings is preferably formed of a plurality of turns of fiber with metallic clips .crimped thereon. A molded belt of rubber, plastic, or a combination of these materials would also serve in this invention.

Identical sprocket wheels

33, 34 are secured on the arm shaft 20 and bed shaft 14, respectively, in substantially vertical register, that is, with the corresponding points on each sprocket pulley disposed in a common plane.

The bracket arm of the sewing machine frame above the standard is formed with an upwardly open slot 35 which exposes the sprocket pulley 33 on the arm shaft. A bridge piece 36 spanning the slot 35 is secured to the bracket arm on both sides of the slot to strengthen the machine frame. At one side of the slot 35, preferably on that side toward the hand wheel, the bracket arm is formed with a pair of outwardly projecting lugs 37 each of which is apertured to accommodate a crank 38. As best illustrated in Fig. 2, the cranks 38 are each formed with an offset crank pin 39 extending from a flange 40 and are threaded, as at 41, to accommodate a washer 42 and a lock nut 43 serving to clamp the crank to the lug 37 in selected angular positions of the crank pin 39. The crank pins 39 are disposed parallel to the arm shaft 26 and by means of the lock nuts 43 may be selectively adjusted toward and away from the arm shaft.

Journaled freely for rotation on the crank pins 39, preferably on needle bearings 44-, are a pair of idler pulleys 45 which are maintained on the crank pins by means of washers 46 and nuts 47 which engage threaded portions 48 on the extremities of the crank pins.

Referring to Figs. 3 and 4, the crank pins 39 and the idler pulleys 45 are arranged on opposite sides of the arm shaft 20, one of the idler pulleys being disposed above and at one side of the arm shaft while the other idler pulley is disposed below and at the opposite side of the arm shaft. The driving belt 31 is arranged such that the inside of the belt engages the sprocket pulley 34 on the bed shaft and both idler pulleys 45, while the outside of the belt engages the sprocket pulley 33 on the arm shaft.

With this construction, a reverse belt drive is attained readily and conveniently in a sewing machine frame.

The continuous belt is maintained in a vertical position with the corresponding points of the belt in a fixed plane, and the tautness of the belt may be adjusted readily by an angular adjustment of the crank pins 39 without influencing the timing between the arm and bed shafts.

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

1. In a sewing machine having a frame including a work supporting bed, a bracket arm overhanging said bed, an arm shaft journaled in said bracket arm and a bed shaft journaled in said bed substantially parallel to said arm shaft, means for drivingly interconnecting said am and bed shafts for turning movement in opposite directions of rotation, comprising substantially co-planar sprocket pulleys secured one on said arm shaft and one on said bed shaft, said bracket arm being formed with an upwardly open slot exposing said sprocket pulley on said arm shaft, a first idler pulley disposed in said slot, means journaling said first idler pulley in said bracket arm on an axis parallel to, above, and at one side of said arm shaft, a second idler pulley disposed on said slot,

means journaling said second idler pulley in said bracket arm on an axis parallel to, below, and at the opposite side of said arm shaft from said first idler pulley, a continuous belt, evenly spaced lugs carried on said belt and extending on both the inside and outside thereof, the

outside of said belt disposed in engagement with the sprocket pulley on said arm shaft, and the inside of said belt disposed in engagement with both said idler pulleys and with the sprocket pulley on said bed shaft.

stantially parallel to said bed shaft, means for drivingly interconnecting said shafts for turning movement in opposite directions of rotation comprising a sprocket pulley fast on a free extremity of said bed shaft, a sprocket pulley fast on said a=rm shaft between said bearings, a first idler pulley journaled on the free extremity of a stud shaft in said frame and disposed above and sutficiently to one side of the axis of said arm shaft sprocket pulley such that a line which is tangential to the pitch circles at one side of said idler pulley and said bed shaft sprocket pulley extends outwardly beyond the periphery of said arm shaft sprocket pulley, a second idler pulley journaled on the free extremity of a stud shaft in said frame and disposed beneath and sufficiently to the opposite side of said arm shaft sprocket pulley such that a line which is tangential to the pitch circles at one side of said idler pulleys extends outwardly beyond the periphery of said arm shaft sprocket pulley, a continuous belt, evenly spaced lugs on said belt and disposed on both the inside and the outside thereof, the inside of said belt being disposed in operative engagement with both of said idler pulleys and with said bed shaft sprocket pulley, and the outside of said belt being disposed in operative engagement with said arm shaft sprocket pulley.

References Cited in the file of this patent UNITED STATES PATENTS