GB2312442A - Looper drive in tufting machine - Google Patents

Abstract

In a tufting machine a rocker shaft (25) carrying loopers is driven from a rotating main shaft (20) through an orbital crank pin (70) which reciprocates a link (75) connected to the looper shaft (25). The main shaft is connected through a belt (60) to a spindle to which the crank pin (70) is detachably connected through a member (65) keyed to the spindle. By replacing the member (65) with another member having a crank pin thereon at a different position the timing of the loopers can be altered.

Description

BELT DRIVEN LOOPER DRIVE This invention relates to a tufting machine and is moie particularly concerned with a looper drive system for a tufting machine.

BACKGROUND OF THE INVENTION In the past, belts have been utilized as part of the drive train for driving the needle bars of tufting machines from the main drive shaft. Examples of such drive systems which utilize belts are found in U.S. Patent No. 4,665,845 and U.S. Patent No. 4,586,445. Such tufting machines, however, have had conventional looper drive systems which employ eccentric cams which drive straps for reciprocating the loopers. Such straps are quite heavy and have materially contributed to the unbalancing of the tufting machine. Such straps are infinitely adjustable and, therefore are difficult to adjust by the same amounts so that the straps at both ends of a looper shaft apply equal torque.

SEARY OF THE INVENTION Briefly described, the present invention includes a conventional tufting machine having a nain drive shaft which supplies power for reciprocating the needle bar and te loopers. This machine has a conventional looper shaft which is disposed below the main drive shaft in parallel relationship thereto. The looper shaft is journaled at its end portions by pillow blocks and has power trains from the main drive shafts, each of which has a freely rotatable spindle disposed above and parallel to the looper shaft.

Each drive train includes a flexible, endless, timing belt, which extends around a pulley or sheave on the main drive shaft and encompasses a sprocket on the end of the spindle so that the sprocket drives the stub shaft in synchronized, timed relationship to the rotation of the main drive shaft at a position closely adjacent to the looper shaft. A concentrically mounted, stroke control lug removably fits onto the radially disposed outer face of the sprocket, and has an eccentrically mounted drive pin which protrudes outwardly from the lug so as to travel in an orbital path when the sprocket is rotated. This drive pin is removably received in a bearing at one end of a short, rigid, link, the other end of which is pivotally connected to the distal end of a looper drive lever which protrudes radially from the looper shaft. Thus, as the sprocket is rotated, the link will be moved upwardly and downwardly for imparting a reciprocal or rocking motion to the looper drive shaft.

Such a construction is ine:ensive, weighing about oneeighth of the weight of the conventional train so that it creates little vibration at high speed. The lugs are readily changeable to alter the stroke and timing of the loopers.

Accordingly, it is an object of the present invention to provide a tufting machine having a looper assembly which substantially reduces the weight of the drive train for rocking the looper shaft.

Another object of the present invention is to provide, in a tufting machine, a drive train which will increase the speed at which the tufting machine may be operated.

Another object of the present invention is to provide a tufting machine in which the amount of heat and friction required for rocking a looper shaft and loopers is reduced to a minimum.

Another object of the present invention is to provide a tufting machine in which the drive train for the looper shaft can be readily and easily re-timed and the stroke of loopers readily and easily altered.

Another object of the present invention is to provide a tufting machine having a drive train for the looper shaft which reduces the vibration of the machine.

Another object of the present invention is to provide a tufting machine in which the drive train for the looper shaft can be readily and easiiy repaired.

Another object of the present invention is to provide a tufting machine in which the looper stroke can be readily and accurately changed and which will provide more positive adjustment of the timing and stroke of the loopers Another object of the present invention is to provide a tufting machine in which the drive train for the looper shaft will allow for better synchronization between the drives on both ends of the machine.

Another object of the present invention is to provide a tufting machine in which the centrifugal and lateral forces generated by the drive train are minimized.

Another object of the present invention is to provide a tufting machine having a drive train which requires no coun.ter-balancing weights to neutralize inertia and centrifugal forces generated by the drive train.

Another object of the present Invention is to reduce to a minimtim the horizontal and vertical vibrations of the tufting machine when it is in operatIon.

Another object of the present invention is to provide a tufting racnine which is inexcens ve to manufacture, efficient in operation and durable in structure.

Other obJects, features and advantages of the present invention will become apparent from the following disclosure when considered in conjunction with the accompanying drawings, wherein like characters of reference designate corresponding parts throughout several views.

DESCRIPTION OF THE DWINGS FIG. 1 is a fragmentary perspective view of a portion of tufting machine having a drive train for the looper shaft, constructed in accordance with the present invention; FIG. 2 is an enlarged fragmentary perspective view of portion of the tufting machine depicted in Fig. 1; FIG. 3 is an enlarged exploded perspective view showing portions of the tufting machine depicted in Fig. 1; FIG. 4 is a vertical sectional view of a portion of the drive train of the tufting machine depicted in Fig. 1; and PIG. 5 is an exploded vertical sectional view of the spindle package of the drive train of the tufting machine shown in Fig. 1.

DETAILED DESCRIPTION Referring now in detail to the emboclment chosen for the purpose of illustrating the preferred embodiment of the present invention, numeral 10 in Fig. 1 denotes, generally, the frame of a conventional tufting machine including legs, such as leg 11, which support a horizontally disposed base plate 12.

A main drive shaft 20 extends transversely throughout the width of the tufting machine, the main drIve shaft 20 being drIven by a motor or motors (not shown) so as to provide newer for reciprocating the needle bars (not shown) for inserting the needles (not shown) through backing material (not shown) as the needles are reciprocated for inserting yarns into the backing material in a conventional way. Such yarns are caught by conventional loopers 21, the loopers 21 being reciprocated in timed relationship to the rotation of the shaft 20. The loopers 21, in turn, are supported by looper bars, such as looper bar 22, which are carried by brackets 23 on shaft 25 mounted on and rocked back and forth by a looper shaft 25 which extends adjacent to base plate 12 and parallel to and below main drive shaft 20.

The frame 10 also includes a top plate 13 and end plate 14, a frcnt plate 15 and a rear plate 16. Tne looper shaft 25 is appropriately journaled by pillow blocks, such as pillow bloc 26, mounted on te base plate 12 and by end support blocks, such as end support block 27, so that the looper shaft 25 is free to rotate or rock back and fort for actuating the loopers 21.

According to the present invention, the looper shaft 25 is rocked back and forth in timed relationship to the rotation of the main-drive shaft 20 by means of a pair of complImentary drive trains, such as drive train 30, best seen in Fig. 2. The drIve trains are mounted in the opposite end portions of the froze 10. Since each drive train, such as drive train 30, is identical and cooperates in driving oppcsite end portions of the looper shaft 25, only the drive train 30 at one end portion of the free 10 is illustrated. This drive train 30 includes an upstanding pillow block denoted, generally, by the numeral 31. This pillow block 31 has a flat base 32 which mounts flat against the upper surface of base plate 12. Base 32 supports a pair of upstanding, longitudinally extending, opposed, complimentary, parallel brackets 33 and 34, the inner surfaces of which are spaced apart by a horizontal crossbar 35 which is parallel to and above base 32. The upstanding brackets 33 and. 34 are provided with lower transversely aligned holes, such as hole 36, which receives roller bearings, such as roller bearing 37, press fitted therein. The looper shaft 25 passes through and is journaled by bearings 37 and is received by the end block 27, as illustrated in Fig. 1. Collars, such as collar 38, carried on the shaft 25, outwardly adjacent the bearings 37, prevents the inner races of the bearings from coming out of their holes and arrest appreciable axial movement of the shaft 25.

At their upper end portions, the upstanding,brackets 33 and 34 are provided with transversely aligned second holes 40 and 41 which are adapted to receive the spindle package denoted, generally, by numeral 42. This spindle package 42 includes a tubular, cylIndrical, bearing housing 43 which receives a pair of oppcsed, spaced, roller bearings or ball bearing 44 which, in turn, journal a stub shaft or spindle 45 which is disposed concentrically with and protrudes from both ends of the housing 43. One end of housing 43 has a butt flange 39. ' hen the pillow block 31 is appropriately mounted on base plate 12, the spindle 45 is disposed in parallel relationship to both the main drive shaft 20 and the looper shaft 25.

when the spindle package 42 is mounted in the maligned holes 40 and 41 of the upstanding brackets 33 and 34, the peripheral shoulder 39 is held in place by a pair of bolts, such as bolt 91 passing through shoulder 39 and into bracket 33.

Spindle 45 has a hollcw counter-bored bore 46, axially through its length and is provided with a circumferential shoulder 47 inwardly adjacent its outer end. At its other or inner end portion, the spindle 45 is provided with a circumferential groove 48 for receiving the snap ring 49.

Press fitted on the end of the spindle 45 is a sprocket 50 which has peripheral teeth 51 and a radially disposed flat outer front face or surface 50a, an alignment pin 52 protrudes from its front face and has an axis parallel to the axis of the shaft or sidle 45. J"'hen the spindle package 42 is assembled, the shaft or spindle 45 is passed through the two aligned roller bearings 44 and is retained thereon by the shoulder 47 abutting one roller bearing 44 and the snap ring 49 abutting the other bearing 44. At its outer end, the spindle 45 is counter-bored to a larder ai=meter to form an outwardly opening socket.

The shaft 20 is provided with a freely rotatable sheave or wheel 55 having external teeth (not shown) along its periphery. Bolts or set screws not shown) secure the sheave 55 in place on shaft 2 0 when it has been timed.

Adjacent to the sheave 55, shaft 20 is provided with a ke,way and 15 keyed to timing disc 56 having indicia 57 thereon. The purpose of this indicia 57 is to permit the pcsitioning of sheave 55 in an appropriately timed reiationship to te other sheave (not shown) at the other end portion of the tufting machine.

The sprocket or wheel 50 senses a double function of being driven by belt 60 in synchronization with the rotation of shaft 20 and of providing a flat radial outer surface for removably receiving and retaining for rotation therewith, the timing or stroke control lug 65 inserted axIally onto the outer surface 50a of sprocket 50. The pin 52 and stub shaft 66 function as an alignment means which assures the appropriate positioning of the lug 65 against sprocket 50, to thereby automatically fix circumferentially and radially the position of the crank or pivot pin 70.

The wheel or sheave 55 is provided circumferentially disposed external teeth (not shown) which mesh with the teeth 61 on the internal surface of a timing belt 60.

This timing belt 60 forms a drive member which passes partially around te sheave 55 and thence partially around the wheel or sprocket 50 received on the end of spindle 45.

Thus, the teeth 61 mesh with the teeth of sheave 55 and teeth 51 of sprocket 50. Hence, the sprocket 50 is rotated by belt 60 in timed synchronous relationship and at the same speed as the main drive shaft 20. Sprocket 50 functions as a receiving plate against which the stroke control lug 65 is mounted.

The function of this timing lug or stroke control lug 55 is to establish both the timing and the stroke or extent of rocking of the looper shaft 25 per revolution andt therefore, the timing and extent of the rocking of the loopers 21. Lug 65 has a disc-shaped body 57 having a central alignment finger or stub shaft 66 protruding from the Inner face or surface of the body 67. Stub shaft 66 is concentric with the periphery of body 57 and concentric with sprocket 50. Its finger or central stub shaft 66 is of a diameter to be snugly received in the counter-bored end portion or socket of the bore 46 of spindle 45. The timing lug 65 is also provided with a hole 68 parallel to and offset from the stub shaft 56 and through which the aliaizment pin 52 protrudes so as to alIgn the lug 65 circumferentially with the sprocket 50.

Protruding outwardly from the outer face or surface of the body 67 of lug 65 is an axIally extending orbital looper drive pin or crank pin 70, the axis of which is parallel to but offset from the axis of the sprocket shaft 45 and stub shaft 66. The distance between the axis of the crank pin 70 and the axis of spindle 45 will determine the extent of the stroke of the loopers 21. The position of the crank pin 70, circumferentially with respect to the pin 52, will determine the timing for the looters 21. Thus, there can be provided a number of interchangeable connec~-na links or looper control lugs 65 in which the crank pin 70 is positioned in oi-erent locations radially and/or circumferentially prescribing different strokes and timis for the loopers 21.

Mounted for reciprocation by the orbital looper drive or crank pin 70 is a rigid iooper drive strap or connecting link 75. This connecting link 75 carries at its upper end portion a roller bearing or ball bearing 76 through which the crank pin 70 protrudes. The lower end portion of the connecting link 75 is provided with a roller bearing or bail rearing 78 through which a removable linch pin 79 projects when the bearing 78 is aligned with opposed holes 81 of G clevis or bifurcated distal end of lever 82. This lever .32, in turn, is removably mounted by the clamping blocs 83 on its proximal end which clamp about the looper shaft 25. Bolts 84 removably secure the two clamping blocks 83 in clamping relationship on opposite sides of the shaft 25 so that lever 82 protrudes sidewise or radially from one end portion of shaft 25, at a position between the end support bloc 27 and pillow block 31.

A draw bolt 90 which passes from the open end of spindle 45 through the bore 46 of the spindle 45 is threadedly received in the end of stub shaft 66, securing the stroke control 1-ug 65 in place. By removing shaft 66, the lug 65 can to be replaced, from time to time, as is deemed necessary. The stroke control lug 65 is quite Inexpensive to manufacture and can readily be replaced when the link or looper drive strap 75 and the bolt 90 are removed.

The belt driven looper drive train of the present invention, as described above, is about one-eighth of the mass of a conventional cam and strap assembly for the tufting machine. The bearings 76 and 78 are much smaller than the bearings necessary for the conventional cam nd strap assembly and, therefore, can operate at much higher rates of speed than the bearings of the conventional cam and strap assembly. Furthermore, these bearings 76 and 78 carry a lighter load and there is less heat generated by them. Also, bearings 76, being spherical roller bearings, can carry both axial loads as well as radial loads.

In this belt driven drive train of the present invention, the parts are much easier to replace, in the event of failure, and the main drive shaft does not required disassembly for achieving most repairs. Indeed, in most instances, the draw bolt 90 and the linch pin 79 are the only parts which need be removed in order to permit the other replaceable parts to be removed and changed. In contrast, in a traditional looper drive system, it is necessary to remove the belts and pulleys which drive the main shaft from te motor, remove the end cover plates of the machine, the bearing pillow blocks, the drive cams and straps to simply replace a ccnve:lticnal drive train.

Furthermore, the removal of the cam and strap assembly or assemblies often results in damage to the main shaft, thereby recuiring replacement of the main shaft.

-In the machine of the present invention, the looper stroke charges are made by simply chancing the- lug and connecting link assembly which includes both the timing lugs, such as lug 65 and an associated link, such as link 75, rather than attempting to adjust notn straps by the same amount in the traditional tufting machine. The use of the identical lugs 65 and links 75 on both ends of the tufting i2chine, allows for immea ate synchronization between the drives on both ends of the machine without the necessity of any timing adjustments relating to the main drive shaft 20. In a conventional looper drive train, the adjustments of the strap are infinite r.aking it difficult to provide exactly the same effective length for straps on both ends of the tufting machine. Furthermore, increasing the length of the prior art straps results in acceleration and displacement differences in the motion of the opposite ends of the machine.

Preferably, the lugs 65 and links 75 of the various assemblies are so matched to each other that each lug and link assembly adds to or subtracts from the arc of travel for the loopers; however, all will prescribe the same retracted position as a starting reference for the loopers but will permit the loopers to travel to different prescribed forwardmost positions.

Due to the low mass of the looper drive train of the present invention, no ccmpensation of counterweights are needed to neutralize the inertia or centrifugal forces generated by the drive train. In addition, the looper drive train has a low center of gravity, which is much lower than that of a conventional cam and strap system and reduces the horizcntal vibrations of the tufting machine.

In the past, special slotted steel straps were needed on machines equipped with sliding needle bars so as to avoid interference with the needle bar shifting drive.

This large heavy strap is eliminated by the present invention, due to the new location and compact nature of the belt looper drive train of the present invention It will be obvious to those skilled in the art that many variations may be made in the embodiment here chosen for the purpose of illustrating the present invention, without departing from the scope thereof as defined by the appended claims..

Claims (1)

1. A tufting process performed on a tufting machine wherein loops of yarn are

inserted through a backing material, the tufting machine having a rotating tufting machine drive shaft and a spaced looper drive shaft that imparts a reciprocating motion to a series of spaced loopers driven thereby so that the loopers catch and temporarily hold the respective loops of yarn formed during the tufting process. said method comprising the steps of: a) moving a pin in an orbital path about an axis in timed relationship with the rotation of the tufting machine drive shaft; b) translating the orbital movement of the pin into a reciprocating motion; and c) imparting the reciprocating motion to the looper drive shaft for rocking the loopers in timed relationship with the rotation of the tufting machine drive shaft.

2. The process of claim 1, including the steps of; a) translating the orbital movement of the pin into a reciprocating motion of an elongate link; and b) imparting the reciprocating motion of the link To an elongate lever fastened at one of its ends to the link and at the other of its ends to the looper drive shaft for imparting the reciprocating motion to the looper drive shaft.

3. A tufting method for forming a series of successive tufts of looped yarn in a backing material being advanced through the tufting zone of a tufting machine, the tufting machine having a frame with an elongate rotatable main drive shaft supported on an upper portion of the frame, a drive motor for rotating the main drive shaft, and an elongate looper drive shaft rotatably supported on a lower portion of the frame spaced from the main drive shaft, the looper drive shaft having a spaced series of loopers disposed thereon with respect to the tufting zone, said method comprising the steps of: a) rotating an elongate spindle shaft supported on a spindle assembly mounted on the frame of the tufting machine with respect to the looper drive shaft in timed relationship with the rotation of the main drive shaft, said spindle shaft extending along a longitudinal axis; b) mounting a control lug assembly on the spindle shaft, said control lug assembly including a crank pin offset from the axis of said spindle shaft; c) orbiting the crank pin about the axis of the spindle shaft in response to the rotation of the spindle shaft; d) reciprocating an elongate drive pinion fastened to the crank pin in response to orbiting the crank pin about the axis of the spindle shaft; and e) rocking the looper drive shaft and the loopers disposed thereon toward and away from the tufting zone in timed relationship with the rotation of the main drive shaft with an elongate drive lever fastened at one of its ends to said drive pinion and at the other of its ends to the looper drive shaft.

4. The method of claim 3, further comprising the step of varying the offset of the crank pin about the axis of the spindle shaft, and varying the timed relationship of the rocking of the looper drive shaft with respect to the rotation of the main drive shaft in response thereto.

5. The method of claim 3, wherein the step of rotating said spindle shaft in timed relationship with the rotation of the drive shaft comprises the steps of: a) positioning a drive sprocket on the drive shaft; b) positioning a driven sprocket on said spindle shaft in substantial alignment with said drive sprocket: and c) encircling said drive sprocket and said driven sprocket with a timing belt for transferring the rotational movement of the drive shaft to said spindle shaft.

6. A tufting method for forming a series of successive tufts of looped yarn in a backing material being advanced through the tufting zone of a tufting machine. the tufting machine having a frame with an elongate rotatable main drive shaft supported on an upper portion of the frame, a drive motor for rotating the main drive shaft. and an elongate looper drive shaft rotatably supported on a lower portion of the frame spaced from the main drive shaft, the looper drive shaft having a spaced series of loopers disposed thereon with respect to the tufting zone, said method comprising the steps of: a) rotating an elongate spindle shaft supported on a spindle assembly mounted on the frame of the tufting machine with'respect to the looper drive shaft in timed relationship with the rotation of the main drive shaft, said spindle shaft extending along a longitudinal axis; b) mounting a first control lug assembly on the spindle shaft, said first control lug assembly including a first crank pin having a first offset distance from the axis of said spindle shaft; c) orbiting the crank pin about the axis of the spindle shaft in response to the rotation of the spindle shaft; d) reciprocating a drive pinion fastened to the crank pin in response to orbiting the crank pin about the axis of the spindle shaft; and e) rocking the looper drive shaft and the loopers disposed thereon toward and away from the tufting zone with a drive lever fastened at one of its ends to said drive pinion and at the other of its ends to the looper drive shaft.

7. The method of claim 6, comprising the steps of: a) replacing the first control lug assembly with a second control lug assembly, said second control lug assembly including a second crank pin having a second offset distance from the axis of said spindle shaft different than said first offset distance; and b) varying the timed relationship of the rocking of the looper drive shaft and the loopers disposed thereon toward and away from the tufting zone with respect to the rotation of the main drive shaft in response thereto.

8. A tufting machine of the type naving a frame, a transversely extending drive shaft in said frame, and a looper shaft in said frame and disposed in parallel relationship to said drive shaft, said looper shaft controlling the rocking of said loopers during the tufting operation of said machine, wherein the improvement comprises: (a) a rotatable spindle journaled in a fixed position on said frame, between said drive shaft and said looper shaft; (b) a drive .,.enDer for transmitting power from said drive shaft to said spindle; (c) a link carried by said spindle for being reciproc-.~d in synchronization with the rotation of said drive shaft; and (d) a lever connected to said link and to said looper shaft for imparting rocking motion to sad looper shaft in synchronization with the reciprocation of said link.

9. The tuftina machine defined in claim 8 wherein the axis of said spindle s parallel to the axes of said drive shaft and said looper shaft.

10 . The tufting machine defined in claim 8 wherein said drive me.-er includes an endless belt passing partially around said drive shaft and said spindle for rotating said spindle.

11. The tufting machine defined in claim 8 wherein said drive member includes a first wheel on said drive shaft, a second wheel on said spindle and an endless belt passing partially around said first wheel and said second wheel.

12. The tufting machine defined in claim 8 wherein said drive member includes a sprocket on the end of said spindle for rotation thereon, a sheave on said drive shaft, an endless flexibie belt passing partially around said sheave and said sprocket for driving said sprocket in synchronization with the rotation of said drive shaft, a pivot pin carried in an orbital path by said sprocket when said sprocket Is rotated, said pivot pin being connected to said link for imparting said reciprocation to saga -n..

13. The tufting machine defined in claim 8 including a pivot pin carried at one end of said sprocket for movement In an orbital path about the axis of said sprocket upon rotation of said sprocket, said pivot pin being received in one end portion of said Ink for imparting saic reciprocation to said link.

14 . - Le tufting machine defined in claim 8 including a lug on one end of said spindle and connected to said link, and a pivot pin cn said lug for being moved in an orbital path when said power is transmitted from said drive shaft for imparting said reciprocation to said link.

15. The tufting machine defined in claim14 including a belt extending between said drive shaft and said spindle for driving said lug.

16. The tufting machine defined in claim 15 including a wheel on the end of said spindle, said wheel carrying said pivot pin and -ecetsing said power from said drive shaft.

17 . The tufting machine defined in claim 16 wherein said wheel on the end of said spindle Is a sprocket and said belt includes ~-ltern l teeth for meshing with the teeth of said sprocket.

18 The tufting machine defined in claim 8 including a wheel on the end of said sprocket, a pivot pin parallel to said spindle for being carried by said wheel n an orbital path about the axis of said spindle, said pin being connected to one end of said link for Imparting said rocking motion to said link.

19. The tufting machine defined In claim 18 wherein said wheel Is provided a radial face with a central opening and including a lug carrying said pin, said lug being removably received against said radial face for rotaton with said wheel when said wheel is rotated.

20. The tufting machine defined in claim 8 including a stroke control lug between said spindle and said link for reciprocating said link upon rotation of said spindle.

21 . The tufting machine defined in claim 20 including a receiving plate on the end of said spindle, said receiving plate having a radially extending outer face and wherein said lug is removably received on said outer face for rotation thereby, said lug having a crank pin protruding axially therefrom far being received in an end of said link.

22. A tuftlng machine for carrying out a tufting operation in which successive tufts are sewn in a backing material, said machine having a frame, a transversely extending drive shaft in the upper portion of said frame and a looper shaft disposed in a lower port ion of said frame parallel to said drive shaft for carrying loopers which engage said tufts, wherein the improvement includes a drive train comprising: (a) a first wheel on said main shaft; (b) a second wheel carried for rotation about an axis parallel to said drive shaft and said looper shaft; (c) an endless belt extending between said first wheel and saic second wheel for driving said second wheel upon rotation of said first wheel; (d) a crank pin carried by said second wheel, said crank pin being offset for said axis of said second wheel for movement n an orbital path about said axis ton rotation of said second 4been; (e) a link connected to said crack pin for being reciprocated by said crank pin upon ;rotation of said second wheel; and (f) a lever protruding sidewise from said looter shaft and having a distal end spaced from said looper shaft, said link being connected to said distal end of said lever for transferring the reciprocal motion of said link into rocking motion of said looper shaft.

23. The tufting machine defined in claim 22. including a spindle for supporting for rota ion of said second wheel below said drive shaft and above said looper shaft.

24. The tufting machine defined In claim 23 including a pillow block supporting said spindle for rotation with said second wheel about said axis of said second wheel.

25. The tufting machine defined in claim 24 in which said second wheel is supported for rotation on an end of said spindle and said crank pin protrudes from said second wheel in a direction away from said axis and is moved in a radial plane of said axis.

25. The tufting machine defined in claim 22 including a stroke control lug removably mounted on a side of said second wheel and said crank pin protrudes from said stroke control lua.

27. The tufting machine defined in claim 26 including an alignment memser between said second wheel and said lug for positioning said lug on said second wheel.

28. Process of tufting in which a drive shaft is rotated for producing a tufting operation in a tufting machine wherein loops of yarn are inserted through a backing material and a looper shaft t imparts reciprocation to loopers which catch and temporarily hold the loops of yarns after such loops of yarns have been formed, wherein the improvement ccrnprises: (a) moving a pin in an orbital path about an axis in timed relationship to the formation of said Icops; (b) translating the orbital movement of said pin into reciprocating movement; and (c) imparting said reciprocating motion to said looper shaft for rocking said loopers in synchrcnizatlon with the rotation of said drive shaft.

2w The process defined in claim 22 including the step of translating the orbital motion of said pin into reciprocal motion of a link and imparting said reciprocal motion of said link to a lever on said looner shaft for imparting said reciprocation to said looper shaft.

30. A tufting machine of the type having a frame, a transversely extending drive shaft in said frame, and a looper shaft in said frame and disposed in parallel relationship to said drive shaft, said looper shaft controlling the rocking of said loopers during the tufting operation of said machine, wherein the improvement comDrises: (a) a rotatable member in said frame, between said drive shaft and said looper shaft for rotation about an axis; (b) a drive member for transmitt ng power from said drive shaft to said rotatable member; (c) a lug carried at one end of said rotatable member for rotatIon therewith; (d) a pivot pin protruding offset from said axis for movement in an orbital path about said axis, upon rotation of said member; (e) a link carried by said pivot pin for being reciprocated in synchronization with the rotation of said drive shaft; and (f) a lever connected to said link and to said looper shaft for imparting rocking motion to said looper shaft in synchronization with the reciprocation of saId link.

31. The tufting machine defined in-claim 30 wherein said lug and said link are replaceable by other lugs and links for varying the stroke of said looper shaft.