US2969757A - Yarn measuring device - Google Patents

Description

Jan. 31, 1961 r. H. DE SPAIN 2,959,757

YARN MEASURING DEVICE Filed Aug. 22, 1958 3 Sheets-Sheet 1 IN V EN TOR.

Thomas EDe Spain 1961 T. H. DE SPAIN 2,969,757

YARN MEASURING DEVICE Filed Aug. 22, 1958 3 Sheets-Sheet 2 I {2 74 r A,

34 INVENTOR. F YZ zomasHDeS vaz'n A TTOFMEMS' Jan. 31, 1961 T. H. DE SPAIN 2,969,757

YARN MEASURING DEVICE Filed Aug. 22, 1958 3 Sheets-Sheet 3 I N V EN TOR. v T/zognas H176 Spain a B C7196 United States YARN MEASURING DEVICE Filed Aug. 22, 1958, Ser. No. 756,699

2 Claims. (Cl. 112243) This invention relates to improvements in metering thread to sewing mechanisms and, particularly, to metering thread supplied to a dial looper in which the quantity of thread fed to the mechanism between successive pieces is reduced to avoid excessive amounts of thread during the chaining-01f operation.

Sewing machines of the type known as dial loopers" are designed for joining adjacent loops of two portions of knitted fabric by an elastic chain of stitches. To afford the desired elasticity of the chain of stitches joining the two portions of knitted fabric, these loopers ordinanly have thread metering devices for controlling the quantity of thread supplied to the sewing mechanism during the looping operation.

During the interval between looping operations, when there is not any work at the sewing mechanisms, these mechanisms perform what is known as a chaining oil operation. As the portions of knitted fabric being joined together leave the sewing mechanism at the end of a looping operation, the sewing mechanism continues to manipulate the thread to form a chain of stitches during the chaining off operation. To afford the necessary elasticity in the chain of stitches formed by the looper in joining two portions of knitted fabric, a greater quantity of thread is required than is normally needed to form a chain of stitches when the portions of fabric have passed beyond the sewing mechanism. As a result, this excess quantity of thread frequently becomes entangled in the sewing mechanism and snarls the chain of stitches desired between looping operations.

A major object of this invention is to supply a metered quantity of thread to the sewing mechanism when work pieces are positioned to be looped together and for supplying a lesser quantity of thread during the chaining oif operation between the looping of two portions of fabric.

In the attainment of this object an important feature of the invention resides in the arrangement of a sensing device actuated by fabric at the sewing mechanism to operate a metering device for feeding metered quantities of thread to the sewing mechanism and actuated when the fabric leaves the vicinity of the sewing mechanism to reduce the quantity of thread supplied to the sewing mechanism. More specifically, a metering device is actuated by the presence of fabric at the sewing mechanism for feeding exact amounts of thread to the sewing mechanism and is rendered inoperative when the fabric leaves the sewing mechanism thereby releasing the thread to a tensioning device for restraining the quantity of thread during the chaining ofi operation.

Other objects, advantages and features of the invention will become apparent from the following specification taken in conjunction with the accompanying drawings, wherein:

Fig. 1 is a top plan view of a portion of a dial looper embodying the invention in its preferred form;

Fig. 2 is a vertical sectional view taken on the line 22 of Fig. 1;

atom G ice Fig. 3 is an enlarged elevation of the thread metering device in operative position;

Fig. 4 is a similar view showing the metering device in inoperative position;

Fig. 5 is a sectional view taken on the line 5-5 of Fig. 4;

Fig. 6 is a View similar to Fig. 4 but with parts removed for purposes of clearness;

Fig. 7 is a perspective view of a work sensing finger shown in Fig. 2; and

Fig. 8 is an enlarged plan view of a portion of a dial showing the formation of chain stitches by a sewing mechanism with a thread control in accordance with the invention.

As shown in the drawings, the invention is embodied in a conventional dial looper similar to the dial looper shown in my patent No. 2,167,104. This machine includes a fixed frame designated generally at 10 upon which an annular dial 12 is mounted for rotation about a vertical axis. A plurality of radially extending work impaling points 14 are mounted upon the periphery of dial 12 to define a work support and project outwardly beyond the edge of the dial so that work material M may be impaled and supported upon points 14 as best seen in Figs. 2 and 8. Rotation of dial 112 carries the work material M past a station at which a stitch forming mechanism or looper designated generally at 16 operates upon the material. Rotation of dial 12 and operative movement of stitch forming mechanism 16 are synchonized by driving both elements from a common drive means designated generally at 18.

As best seen in Fig. 2, stitch forming mechanism 16 includes an arm 20 which is mounted for oscillating rotary movement about an axis defined by a shaft 21 which is supported in the frame of the machine. A needle 22 mounted at the outer end of arm 2%) is positioned to pass thread 24 through the work material M upon each oscillation of arm 20. For details of the operation and driving mechanism of the machine, reference is made to my Patent No. 2,167,104.

As previously stated, the present invention is concerned with control of the feed of thread 24 to the stitch forming mechanism. Thread 24 is supplied to the stitch forming mechanism 16 from a schematically illustrated thread supply 26. Fro-m supply 26, the thread passes through a thread guide 28 mounted upon the machine frame and is then led through a thread tensioning device 30 of conventional construction. From tensioning device 30, the thread passes over a portion of the periphery of a feed roller 32 whose periphery is defined by an annular rubber tire 34. Feed roller 32 is mounted upon a shaft 36 which is journaled for rotation in bracket 23 on shaft 21 and fixed relative frame '10 of the machine. During normal operation of the looper, the thread is firmly pressed against the rubber periphery of feed roller 32. by a roller 38.

The shaft 36 to which roller 32 is fixed is driven from a conventional ratchet mechanism 4i) (Fig. 1) which is coupled to drive mechanism 18 to operate in synchronism with rotation of dial 12 and stitch forming mechanism 16. As explained in more detail in my Patent No. 2,167,- 104, the operator of the machine may regulate the amount of thread fed to the stitch forming mechanism by adjustment of ratchet mechanism 40. From feed roller 32, thread 24 passes through suitable guides such as 42, '44, 46 and 48 to needle 22.

Referring now to Fig. 5, roller 38 is mounted for rotation upon a shaft 50 which is journaled for rotation in bracket 23. Roller 38 is carried upon an extension 52 of shaft 50 which is eccentrically located with respect to the axis about which shaft 50 rotates as a whole. Roller 38 is freely mounted upon extension 52 and is main;

tained in position upon the extension by means of a nut and washer 54, 56, respectively, mounted upon a projecting stud 58 integral with shaft 50.

Shaft 50 is rotated by an arm 60 which is fixed .to shaft 50 as by a pin or set screw 51.

The upper end of arm 60 is pivotally coupled as at 62 to the plunger 64 of a solenoid 66. Solenoid 66- is mounted upon bracket 23 and, when enegized, rotates arm 60 to the position shown in Fig. 2. A coil spring 68 is also connected in tension between arm 60 and bracket 23 as at 70 and acts to pivot arm 61 in a counterclockwise direction in Fig. 2 when solenoid 66- is not energized. Rotative movement of arm 60 about the axis defined by shaft 50 under the action of spring 68 is limited by means of a stop 72 which is bolted to bracket 23.

Solenoid66 is energized and deenergized by a snap action switch 74 mounted upon frame by means of a bracket 76 at a location slightly in advance of the stitch forming mechanism 16. Switch 74 includes a striker 78 positioned to be engaged by work material M when material is aligned with needle 22 of stitch forming mechanism 16. The internal electrical connections of switch 74 are such that when striker 78 is engaged by work material M, the contacts of switch 74 are closed. Switch 74 is connected in a suitable electrical circuit schematically illustrated in Fig. 1 so that solenoid 66 is energized whenever striker 78 is engaged by work material M. The construction of switch 74 is conventional and will'not be described in detail.

In operation, the operator positions work material upon impaling points 14 of dial 12 with the pieces of work material normally spaced from each other as shown in Fig. 8. As the dial turns, the spacing between adjacent pieces of work material M as indicated in Fig. 8, creates two different conditions at the stitch forming mechanism 16. In one condition, work material is present and stitch forming mechanism 16 performs a looping operation upon the work material. In the other condition, no work material is present at the stitch forming station and the mechanism performs what is known as a chaining ofi operation. For most efiicient looping, it is desirable that an accurately measured length of thread be advanced to the stitch forming mechanism 16 for each stroke. This amount of thread is greater than that required during the chaining off operation and, in order to prevent the feeding of excess thread to needle 22 during-the chaining 01f operation, the structure described above operates as follows.

During the looping operation, a portion of work material M is in position to receive needle 22 during the stroke of the needle. Whenever work material M is in this position, illustrated in Fig. 2, striker 78 of snap action switch 74 engages the work material and, because of the thickness of the work material, striker 78 is moved to a position which closes the contact of switch 74. Closing-of the contacts of switch 74 energizes solenoid 66, thereby retracting plunger 64 to dispose arm 60 in the position shown in Fig. 2.

Referring now to Fig. 3, which is a detail view of arm 60 and roller 38 when arm 60 is in the Fig. 2 position, it will be seen that roller 38, because of its eccentric disposition upon shaft 50, is forced downwardly against roller 32 to firmly grip thread 24 between roller 38 and the rubber periphery 34 of roller 32. The force with which roller 38 is pressed against the periphery of roller 32 to grip thread 24 between the rollers is greater than the tensioning grip exerted by thread tensioner and the action of feed roller 32 overrides the action of tensioner 30 during the looping operation. Thus, for each operative stroke of stitch forming mechanism 16, feed roller 32 is rotated a predetermined amount to feed the necessary length of thread 24 to needle 22.

When the piece of work material M upon which the looping operation is performed passes beyond the stitch forming mechanism 16, striker 78 is biased, :as by a suitable spring, outwardly into engagement with the periphery of dial 12. When striker 78 moves to this position, the contacts of switch 74 are opened to deenergize solenoid 66 so spring 68 biases arm 60 from the position in Fig. 2 to the vertical position shown in detail in Fig. 4. This causes shaft 50 to rotate in a counterclockwise direction and, as best seen in Fig. 4, rotates the eccentric extension 52 upon which roller 38 is mounted upwardly away from the periphery of feed roller 32.

As best seen in Fig. 4, when arm 60 is in the vertical position, the peripheral surface of roller 38 is no longer in contact with the periphery of feed roller 32 and hence no gripping action is exerted upon thread located between roller 38 and feed roller 32. In this condition, feeding movement of thread 24 is completely controlled by tension device 30. The tension exerted upon thread 24 by tension device 30 is selected to be such that no excess thread is fed to needle 22 during a chaining off operation. Since tensioning device 30 prevents excess thread from being fed to needle 22, there is no possibility of excess thread becoming entangled in the stitch forming mechanism.

While I have described and illustrated one embodiment of my invention, it will be apparent to those skilled in the art that the disclosed structure is capable of being modified. Therefore, the foregoing description is to be considered exemplary rather than limiting and the true scope of my invention is that defined in the following claims.

I claim:

1. In a sewing machine having a work support, and stitch forming means for forming stitches in fabric on said work support; thread feeding means comprising a first roller mounted for rotation about a fixed axis, a shaft mounted for movement toward and away from said first roller, a second roller mounted for rotation on said shaft and movable with said shaft between a first position wherein said second roller is in rolling engagement with the periphery of said first roller and a second position wherein said second roller is out of engagement with said first roller, means guiding thread to be fed to said stitch forming means along the periphery of said first roller at a location where said thread may be gripped between said rollers when said second roller is in said first position, means for rotating said first roller through a predetermined movement in synchronism with each stitch formed by said stitch forming means, means responsive to the presence of fabric on said work support in position to be acted on by said stitch forming means for moving said second roller to said first position to grip thread between said rollers and thereby feed a predetermined quantity of thread to said stitch forming means upon each rotative movement of said first roller, and means responsive to the absence of fabric on said Work support in position to be acted on by said stitch forming means for moving said second roller to said second position.

2. In a sewing machine having a work support, stitch forming means for forming stitches adjacent said work support, and thread tensioning means for tensioning thread fed to said stitch forming means, thread feeding means located between said tensioning means and said stitch forming means comprising a first roller mounted for rotation about a fixed axis, a shaft mounted for movement relative to said first roller, a second roller mounted for rotation on said shaft and movable with said shaft between a first position wherein said second roller is in rolling engagement with the periphery of said first roller and a second position wherein said second roller is out of engagement with said first roller, means guiding thread to be fed to said stitch forming means along the periphery of said first roller at a location where said thread may be gripped between said rollers when said second roller is in said first position, means for rotating said first roller through a predetermined movement in synchronism with each stitch formed by said stitch forming means, means responsive to the presence of fabric on said work support in position to be acted on by said stitch forming means for moving said second roller into engagement with said first roller to grip thread between said rollers With a force suflicient to overcome the tensioning force exerted on said thread by said thread tensioning means to thereby feed a predetermined quantity of thread to said stitch forming means upon each movement of said first roller, and means responsive to the absence of fabric on said work support in position to be acted on by said stitch forming means for moving said second roller to said second position to permit the quantity of thread fed to said stitch forming means to be limited by said thread tensioning means.

References Cited in the file of this patent UNITED STATES PATENTS Chadbourn Oct. 15, Diehl Dec. 1, Topham Dec. 31, Walser et a1. May 27, Lindgren July 13, Menschner May 3, Jorgenson Oct. 23, Winz Oct. 27,

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