US2756462A - Drafting mechanism - Google Patents

Description

y 31, 1955 G. D. LOVE ETAL 2,756,462

DRAF'I ING MECHANISM Filed Nov. 7, 1952 mmvron GE 1:. LOVE By DAVID B. HOPKINSOIV United States Patent DRAFTING lvmcrrAmsM George D. Love, Saco, and David B. Hopkinson, Kennebunk, Maine, assignors to Sam-Lowell Shops, Boston, Mass.,a corporation of Maine Application November 7, 1952, Serial No. 319,272

6 Claims. (Cl. 19-131) This invention relates to textile fiber drafting mechanisms for spinning and roving frames and pertains more specifically to a textile drafting mechanism capable of drafting fibers of widely varying lengths and characteristics, particularly extremely long fibers as Well as mixtures of fibers of such widely varying lengths and characteristics.

With the development of synthetic textile fibers in recent years, the range of staple lengths available has been greatly broadened. In particular, fibers having extremely long fiber lengths have been made available. In addition, mixtures of such synthetic fibers with various natural fibers, such as cotton or wool, have come into widespread use as well as mixtures of two or more different synthetic fibers, which may be of the same or different lengths. has been used for many years for drafting short fibers, such as cotton, or for drafting long fibers, such as wool, has not been completely satisfactory for handling mixtures of fibers of such widely varying lengths and characteristics.

It has heretofore been proposed to solve the foregoing ditficulties by employing a drafting apparatus of the apron type having between a pair of delivery rolls and a pair of back rolls a fiber control mechanism comprising an overlying roll cooperating with an endless apron to control the fibers, the endless apron generally having an apron driving roll and an apron bar as well as a suitable tensioning roll within its loop, and with the overlying roll run ning in a depressed curve of the apron and providing a control zone having a soft yielding grip on the sliver being drafted. By varying the mounting and/or weighting on the overlying apron roll, it is possible to employ such an apparatus either as a single zone drafting mechanism, in which the main draft occurs between the back rolls and the delivery rolls with a slip draft between the apron and its overlying roll, or to use it as a two-zone drafting mechanism with the fibers being firmly nipped between the apron and the overlying roll. However, in either case, the control of the fibers being drafted depends largely upon the extent of the arc of contact between the apron and the overlying roll forward of the apron driving roll. In order to provide a sufficiently long are of contact, it has been necessary to set the apron bar rather close to the apron driving roll. Hence, in the case of very long fibers, where it is desirable to have the control mechanism set well back from the delivery rolls so as to control the fibers from their tail ends only, it has been impossible to provide any support for the sliver in the region between the apron bar of the control mechanism and the delivery rolls, the sliver being held together in this region solely by the inter-fiber friction. This situation is particularly undesirable when a blend of long and short fibers is being drafted, since little or no control over the short fibers is provided by such an arrangement, especially near the nip of the delivery rolls.

It is an object of the present invention to provide a drafting mechanism having spaced delivery rolls and The conventional drafting mechanism which i ree holding rolls provided in the space therebetween with a control mechanism of the apron type having the delivery end of the apron extending well up to the nip of the delivery rolls.

Another object is to provide a drafting mechanism having spaced delivery rolls and holding rolls provided with a fiber control mechanism of the apron type, either a single zone drafting device or a two-zone drafting device, which provides continuous support for the fibers from the fiber control mechanism to a point adjacent the nip of the delivery rolls regardless of fiber length.

Another object is to provide a drafting mechanism in which the fiber control mechanism is adjustable to and from the delivery rolls without separation of the apron from the delivery rolls and without loss of control over short fibers.

Another object is to provide a mechanism of the type described having two apron bars which are readily removable so as to convert the device, if desired, from a long fiber to a short fiber drafting mechanism.

Still other objects will be apparent from the drawings and from the description which follows.

In the drawings,

Fig. l is a vertical section of a drafting mechanism embodying the present invention, and

Fig. 2 is a detailed vertical section of one portion of the device showing a second embodiment of the invennon.

Referring first to the embodiment shown in Fig. l, the device includes a pair of delivery rolls 8 and 9 at its forward end, an intermediate pair 10 and 11, and a back pair 12 and 13 at its rearward end. Lower rolls 9, 11 and 13 extend for substantially the entire length of the machine and are driven by conventional gearing (not shown) located at the end of the spinning or roving frame. Lower roll 9 is mounted in bearing block 14 secured toroll stand 15 while lower holding roll 13 is mounted in hearing block 16 adjustably secured to a track 17 in the upper face of roll stand 15 by means of bolt and nut 18.

Upper rolls 8 and 12 are mounted in guide members 20 and 21 adjustably secured on cap bar 22. Trumpet 23 mounted on bar 24 serves to guide and feed the sliver between holding rolls 12 and 13.

The fiber control mechanism mounted between the holding and delivery rolls includes positively driven apron driving roll 11 and apron bar 26 mounted in slots on hearing block 27, which is adjustably secured to the track of the roll stand by means of bolt and nut 28 so as to be movable to and from delivery rolls 8 and 9. An auxiliary apron bar 29 is mounted on hearing block cap 19 on hearing block 14. Apron 30 passes about apron driving roll 11, apron bar 26 and auxiliary apron bar 29, being held under tension by apron tensioning roll 31 engaged by arms 32 pivoted on rod 33. Overlying top apron roll 10 contacts the outer face of apron 30 between apron driving roll 11 and apron bar 26, this roll being supported by the outer race 35 of its anti-friction bearing resting on seat 36 of cap bar fitting 37. Accordingly roll 10 thus supported is free to move only along seat 36 to and from apron driving roll 11 so as to nip apron 3i and the sliver between the two rolls. Control roll 4%) is mounted in slots 41 in guide member 42 adjustably secured to cap bar 22 disposed above auxiliary apron bar 29. Control roll 4%) is urged against the top face of apron 3b as it passes over auxiliary apron bar 29 solely by its own weight, being free to slide in slot 41, so that slippage of the fibers occurs between the roll and the apron.

A suitable weighting arrangement for the top rolls is shown, similar to that of Rabasa U. S. Patent No. 2,381,856, in which a cartridge 45 containing a compression coil spring is mounted on main frame 46 so as to urge pusher rod 47 upwardly against lever arm 48. Lever 48 is pivoted at 49 on a pivot support 50, which is threaded at its lower end and adjustably secured to frame 46 by nuts.51 51. A lugSZat the opposite end of lever 48 is engaged by connectingmember-SZ whichyin turn i pivoted to floating lever 54. Weight hooks 55 and 56 are in turn pivoted at opposite ends of lever 54, hook 55 resting on the arbor of top delivery roll 8 and hook 56 resting on saddle 57 which in turn bearsupon the arbors of top rolls and 12.

In the embodiment shown in Fig. 2, auxiliary apron bar 29 is separately mounted on bearing block 69, which is adjustably secured on track 17 of the roll stand by means of nut and bolt 61. With this arrangement the auxiliary apron bar may readily be adjusted toand from the nip of delivery rolls 8 and 9 or may be completely removed from the device without the necessity for dis turbing the mounting of thedelivcry rolls.

It should be noted that the use of control roll 49 bearing on apron 3% as it passes over auxiliary apron bar 29 is optional, being unnecessary in the case of certain fibers but being desirable in the case of others having different surface characteristics.

The rolls employed may be of any conventional con struction. Bottom rolls 9, 11 and 13 are of suitably fluted or roughened steel so as to grip and hold securely the fibers of the sliver or the inner face of the apron, as the case may be. Top rolls 8, 10 and 12 are suitably provided with resilient bosses or covers made of cork, leather, synthetic rubber, or the like. Control roll 40 is suitably a steel roll; in the case of many fibers it is beneficial to use a heavy roll at this point, the weight being just less than enough to cause cockling of the fibers. Apron 30 may be made of any suitable natural or synthetic material, leather being commonlyemployed. Roll speeds will vary depending upon the draft desired, as pointed out in some detail in Shaw U. S. Patent No. 2,233,963; with a weighted upper apron roll, as shown, it is generally desired to adjust speeds so as to obtain a break draft between the holding rolls and the fiber control mechanism, with the main draft being obtained between the fiber control mechanism and the delivery rolls. However, the weighting arrangement may be adjusted so that the middle top roll '10 operates as a slip roll instead of a drafting roll, if

desired. In this case it is desirable to provide a supplemental apron driving roll as described and claimed in the co-pending application of Burnham and Adams Serial No. 230,986 filed June 11, 1951. When roll 10 is arranged to operate as a slip roll, the main draft will occur between delivery rolls 8 and 9 and back rolls l2 and 13, and will be determined by the relative peripheral speeds of these two sets of rolls, since the fibers are not firmly gripped between top apron roll 10 and apron 39.

In either event, whether a slip draft occurs between top roll 19 and apron 30 (single-zone drafting), or top roll 10 is weighted so .as to grip the fibers firmly (two-zone drafting), back rolls 12 and '13 function as holding rolls. In the case of two-zone drafting, of course, middle rolls 1i) and 11 should be spaced from delivery rolls 8 and 9 and from back rolls 12 and 13 a distance greater than the average fiber length of the sliver.

'With the arrangement of the driving mechanism shown, itwillbe apparent that the fibers, as they pass between roll 10 and apron 30, are gripped and held by these respective elements, the degree of gripping and holding depending upon the weighting of top roll 10. Whatever the degree of weighting, it will be apparent that the pressure between apron 30 and top roll 10 decreases gradually forwardly from apron driving roll 11 so as to provide a soft grip on the fibers of the sliver. Furthermore, apron 30, as it extends forward over auxiliary apron bar 29, continues to support the sliver after it leaves top roll 10 up to a point closely adjacent the nip of the delivery rolls. While this added support alone is sufiicient to retain satisfactory control over the fibers in many cases, supplemental control roll 40 overlying auxiliary apron bar 29 provides an additional means for/ controlling the fibers between top roll 10 and the nip of the delivery rolls. This arrangement makes it possible to control long fibers during drafting by holding only the tail ends of the fibers between top roll 10 and apron 31' (as is particularly desirable in the case of long staple nylon fibers) while at the same time supporting the fibers, which would otherwise be limp, in the space between top roll 10 and the nip of delivery rolls 8 and 9. Furthermore, this-arrangement makes it possible to provide adequate control of blends containing a mixture of short'fibers with suchlong fibers while at the same time providing for taihend ,control of the long fibers.

Although we have herein described specific embodiments of our invention, we do not intend to limit ourselves thereto but to include all of the variations and modifications within the scope .of theappended claims.

We claim:

1. In a drafting mechanism, .the combination of a first pair of upper and lower rolls arranged to grip and draw a sliver therebetween, a second pair of upper and lower rolls behind the first pair between which the sliver is fed on its way to the first pair of rolls, an endless apronzrunning over the lower roll of said second pair of rolls, a first apron-supporting bar disposed between said lower rolls beneath said apron, said upper roll of said second pair of rolls bearing upon said apron and depressingit between said bar and said lowerroll of said second pair of rolls, supporting means for directly supporting said first apron bar for adjustable movement toward and away from the first pair of rolls and a second apron-supporting bar disposed beneath said apron adjacent the nip of the first said pair of rolls, the second pair of rolls and the first apronesnpporting bar being supported independently ofand adjustable toward and away from the first pair of rolls independently of the second apron-supportingibar.

2. A drafting mechanism of the character described comprising a pair of delivery rolls at the forwardend and a pair of holding rolls atits oposite end, .means sup.-

porting said rolls to act simultaneously on portions of a sliver spaced apart by a distance greater than the average fiber length of the sliver to feed and draft it, means for revolving said rolls, and a rotary fiber control mechanism mounted between said pairs of rolls, said control mechanism including an endless looped underlying sliversupporting apron, a positively driven apron-supporting r011 within the "loop of and in contact with saidapron for supporting and driving said apron, supporting means for said apron supporting roll directly supportingsaid.

apron supporting roll for adjustable movement toward and away from said delivery rolls a first apron bar mounted on said supporting means and disposed forwardly of said supporting roll within the loop of said apron and in contact therewith, an upper roll overlying said. apron outside the loop thereof between the apron=supporting roll and the apron bar, and a second apron bar disposed forwardly of the first said bar adjacent nip of the delivery rolls within the loop of the apron, said apron-supporting roll, upper roll, and first apron bar being movably adjustable toward and away from thedelivery rolls independently of said second apron bar.

3. A drafting mechanism of thecharacter described comprising a pair of delivery rolls at the forward endand a pair of holding rolls at its opposite end, means support ing said rolls to act simultaneously on portions of a sliver spaced apart by a distance greater than the average fiber length of thesliver to feed and draft it, .means for re volving said rolls, and a rotary fiber control mechanism mounted between said pairs of rolls, said .controlmechanism including an endless looped underlying sliver-sup porting apron, a positively driven apron support-ing roll within the loop of and in contact with said apron for sup- P n n ng said apron, upp rtingrncanstm aid apron supporting roll directly supporting said porting roll for adjustable movement toward and away from said delivery rolls a first apron bar mounted on said supporting means and disposed forwardly of said supporting roll within the loop of said apron and in con tact therewith, an upper roll overlying-said apron outside the loop thereof between the apron-supporting roll and the apron bar, a second apron bar disposed forwardly of the first said bar adjacent the nip of the delivery rolls within the loop of the apron, and a control roll overlying the upper face of said apron above said second apron bar, said apron-supporting roll, upper roll, and first apron bar being movably adjustable toward and away from the delivery rolls independently of the second apron bar and control roll.

4. A drafting mechanism of the character described porting and driving said apron, supporting means for said apron supporting roll directly supporting said apron sup-' porting roll for adjustable movement toward and away from said delivery rolls a first apron bar mounted on said supporting means and disposed forwardly of said supporting roll within the loop of said apron and in contact therewith, an upper roll overlying said apron outside the loop thereof between the apron-supporting roll and the apron bar, and a second apron bar disposed forwardly of the first said bar adjacent the nip of the delivery rolls 5 within the loop of the apron, said second apron bar being movably adjustable toward and away from said delivery rolls independently of all of the other rolls and said apron-supporting roll, upper roll and first apron bar being movably adjustable toward and away from the delivery rolls independently of said second apron bar.

5. A drafting mechanism 'of thecharacter described comprising a pair of delivery rolls at the forward end and a pair of holding rolls at its opposite end, each of said pairs of rolls comprising atop roll and a bottom roll, means supporting said rolls to act simultaneously on portions of a sliver spaced apart by a distance greater than the average fiber length of the sliver to feed and draft it, means for revolving said rolls, and a rotary fiber control mechanism mounted between said pairs of rolls, said control mechanism including an endless looped underlying sliver-supporting apron, a positively driven apron-supporting roll within the loop of and in contact with said apron for supporting and driving said apron, supporting means for said apron supporting roll directly supporting said apron supporting roll for adjustable movement toward and away from said delivery rolls a first apron bar mounted on said supporting means and disposed forwardly of said supporting roll within the loop of said apron and in contact therewith, an upper roll overlying said apron outside the loop thereof and depressing the apron between the apron-supporting roll and the apron bar, a second apron bar disposed forwardly of the first said bar adjacent the nip of the delivery rolls within the loop of the apron, a control roll overlying the upper face of said apron above said second apron bar, said apron-supporting roll, upper roll, and first apron bar being movably adjustable toward and away from said delivery rolls independently of said second apron bar and control roll, and means for urging each of the top delivery roll, the upper apron roll, and thetop holding roll toward the corresponding opposing roll to grip the fiber therebetween.

6. A drafting mechanism of the character described comprising a pair of delivery rolls at the forward end and a pair of holding rolls at its opposite end, each of said pairs of rolls comprising a top roll and a bottom roll, means supporting said rolls to act simultaneously on portions of a sliver spaced apart by a distance greater than the average fiber length of the sliver to feed and draft it, means for revolving said rolls, and a rotary fiber control mechanism mounted between said pairs of rolls, said control mechanism including an endless looped underlying sliver-supporting apron, a positively driven apronsupporting roll within the loop of and in contact with said apron for supporting and driving said apron, supporting means for said apron supporting roll directly supporting said apron supporting roll for adjustable movement toward and away from said delivery rolls a first apron bar mounted on said supporting means and disposed forwardly of said supporting roll within the loop of said apron and in contact therewith, an upper roll overlying said apron outside the loop thereof between the apron-supporting roll and the apron bar, a second apron bar disposed forwardly of the first said bar adjacent the nip of the delivery rolls within the loop of the apron, said apron-supporting roll, upper roll and first apron bar being movably adjustable toward and away from the delivery rolls independently of said second apron bar, and means for urging each of the top delivery roll, the top holding roll and the upper apron roll toward the corresponding opposing roll to nip the fiber therebetween.

References Cited in the file of this patent UNITED STATES PATENTS 2,233,963 Shaw Mar. 4, 1941 2,426,425 Zalkind Aug. 26, 1947 FOREIGN PATENTS 712,800 Germany Oct. 25, 1941

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