US3091814A

US3091814A - Textile drafting mechanism

Info

Publication number: US3091814A
Application number: US722673A
Authority: US
Inventors: Huber Richard; Kubler Friedrich
Original assignee: SKF Kugellagerfabriken GmbH
Current assignee: SKF GmbH
Priority date: 1957-03-29
Filing date: 1958-03-20
Publication date: 1963-06-04
Anticipated expiration: 1980-06-04
Also published as: BE565809A; DE1050696B; CH361513A; GB885974A; FR1204438A

Description

June 4, 1963 R. HUBER A|51- AI 3,091,814

TEXTILE DRAF TING MECHANISM Filed March 20, 1958 3 Sheets-Sheet 1 ATTYS.

June 4, 1963 R. HUBER ET AI.

TEXTILE DRAFTING IIEcIIIINIsI/I 3 Sheets-Sheet 2 Filed March 20, 1958 INVENTORSI RICHARD HUBI-:R FRIEDRICH KBLER Bv im ATTYS.

June 4, 1963 R. HUBER ETAI 3,091,814 TEXTILE DRAFTING MECHANISM Filed March 20, 1958 3 Sheets-Sheet 3 INVENTORS RICHARD HI'JBER FRIEDRICH KUBLER ATT YS.

United States Patent Ciice 3\,9l,8l4 Patented .lune 4, 1963 3,91,814 TEXTLE DRAFTM G MEQHANlSM Richard Huber, Stuttgart-Nord, and Friedrich Khler, Stuttgart-Bad Cannstatt, Germany, assignors to SKF Kugellagerfabriken Gesellschaft mit hesehrankter Haftung, Schweinfurt, Germany, a corporation of Germany Filed Mar. 20, 1958, Ser. No. 722,673 Claims priority, application Germany Mar. 29, 1957 13 Claims. (Cl. 19-28i) This invention is for improvements in or relating to textile drafting mechanism and is concerned with mechanism having a pivotally mounted top-roll carrier arm which can be locked, in the operating position, to a station-ary part of the machine and which receives top rolls on guide arms which are adapted for lateral swinging on the top rolls.

For the faultless operation of a drafting mechanism, it is necessary for the axes of the top rolls to be parallel to those of the bottom rolls during operation. For this reason, constructions have been designed wherein the twin top rolls are mounted in guide arms received for lateral swinging movement in the top-roll carrier arm, so that they can automatically align themselves parallel to the bottom rolls during operation. The biasing or weighting of the top rolls is effected, in these constructions, by helical springs which bear at one end on the guide arm and at the other end lagainst a fixed abutment in the toproll carrier arm. Although helical springs have proved satisfactory in practice as weighting means yfor top rolls at low weighting pressures, they have the disadvantage that, in addition to forces acting in the direction of their central longitudinal axis, laterally acting forces also arise which, particularly at high pressures, assume a value which counteracts an accurate self-alignment of the guide arms or of the twin top rolls parallel to the bottom rolls. As a result, there is interference with the advantageous results intended to be obtained by the provision for lateral swinging of the guide arms in the top-roll carrier arm or this lateral swinging may be entirely prevented if very in quality of the yarn produced.

In order to overcome this disadvantage, it has been proposed that the springs should Ibe tested for the direction of their aforesaid lateral forces before being installed in the drafting mechanism, and should be installed in the drafting mechanism in such a setting that the said lateral forces operate in a neutral direction, that is to say longitudinally of the top-roll carrier arm. In this manner, the action of the lateral forces was rendered comparatively harmless. However, the testing of each individual spring which was necessary, and the careful installation thereof in the drafting mechanism, involved considerable expenditure of time and labor and hence corresponding high costs.

In drafting mechanisms in which very high weighting pressures are required, one helical spring is often not sufficient as a weighting means, so that a plurality of weighting springs have to be installed, connected one behind the other, for example. As a result of the adoption of this construction the lateral forces of the springs are apt to assume too high a value, and in addition, a clumsy arrangeon which rest the weighting means acting.

ment of the elements of the drafting mechanism is involved. In many cases, moreover, the space necessary for the installation of additional weighting springs is not available inside the drafting mechanism. However, it is impossible to obtain a very high weighting pressure on a guide arm with only one single helical spring because this would have to be of a comparatively stijf construction or would reach dimensions which would make it unsuitable for installation in a drafting mechanism. A particular disadvantage of stiff helical springs, apart from a correspending increase in the lateral force, is the relatively steep spring characteristic. This means that in the event of the guide arm carrying the top rolls swinging down to the plane of the drafting field to differing extents, there is a marked variation in the pressure acting on the corresponding top rolls. In practice, however, such variable downward swinging cannot 'be avoided because the roll covers are reground at intervals and become smaller in diameter as a result, so that the guide arm swings further down `and the spring exerts a considerably reduced pressure on the top rolls in accordance with the aforesaid steep characteristic. On the other hand, there would be a corresponding increase in pressure if the spring force were adapted to an laverage roll diameter and a top roll of maximum diameter were used. Such variations in weighting pressure, combination with the inaccurate parallel alignment of the `axes of the top rolls with those of the bottom rolls, caused by the aforesaid lateral forces of the springs, lead to uneven and faulty yarn when the drafting mechanism is in operation.

It is an object of the present invention to overcome these disadvantages and to provide a drafting mechanism wherein the transmission of high pressures to the top rolls is -assured without adversely affecting their satisfactory self-alignment parallel with the bottom rolls, and wherein despite defection of rolls, during operation, a substantially constant pressure is assured. According to the invention, this object is achieved by arranging that `the weighting means allocated to the guide arm are mounted, together with their seatings, for lateral swinging movement, and that the guide arms are supported with point or line contact by two retaining members arranged inside the top-roll carrier arm. By the adoption of this arrangement, the adverse effect of the aforesaid lateral forces of the springs is eliminated in a reliable manner during the operation of the drafting mechanism, while the aforesaid lateral swinging movement takes place in directions parallel to the plane of the drafting iield b arm for lateral swingthe guide ar-m carrying the top tance between the top rolls can easily be varied by adjusting members. The stirrups may, like the guide arm, be manufactured in a simple manner from sheet metal so that the seatings for the weighting means, which may, for example, take the form of helical springs, can be mpressed directly in the guide arms.

The retaining members may be two in number, one 'located above the other and the guide arms may be bent into substantially right angled formation with one portion engaging at its end around the upper retaining member after the fashion of half a bush, and being supported against the lower retaining member either directly or through an interposed additional member. As mentioned above, the retaining members are preferably in the form of pins. These may advantageously be arranged with their longitudinal axes parallel to the aries of the top rolls and be provided with bearing surfaces lfor the guide arms or for the holders carrying the guide arms. For example, the bearing surfaces may be constituted by the cylindrical surfaces of the pins or may consist fof circumferential grooves in which correspondingly shaped ribs on the guide arms or holders engage. Such'ribs may alternatively rest on the cylindrical surface :of the pins. In either case, it is advisable to select the dimensions in such a manner that only a point Y or line Contact is obtained on the pins as a result of whichl there is practically no friction which might hamper satisfactory self-alignment of the guide arms.

It is also contemplated, in carrying out the present invention that the guide arm may be formed of resi-lient material through tension in which the top rolls are biased or weighted, and, if desired, an additional weighting spring may be allocated to one or more guide arms in a carrier arm. 'The weighting pressures may be considerably increased by the installation of an additional weighting spring, the characteristic curve of which is comparatively gradual so that, in the event of a variation in the distance which the guide arm swings downwardly carrying the top rolls towards the corresponding bottom rolls, no variation in weighting pressure takesplace or only a slight variation which is insignificant in practice.

The additional fweighting spring aforesaid may take the form of a leaf spring and may be bent at an angle and mounted inside the guide arm, and provided with Vguide means, for example an impressed trough, which engages over a correspondingly formed guide, for example a rib, in the guide arm. The angular additional weighting spring may, with advantage, be supported at each end on portions 'of the guide arm.

The additional weighting spring may also take the form of a helical spring, one end ci which bears on one portion of the guide arm, while its other end bears on a support carried on the other portion of the guide arm. The said support may either be integral with the guide arm lor be mounted thereon as an added member as desired. The latter alternative enables the guide arms to be modiiied in a simple manner to receive additional weighting springs as a result of which, as mentioned above, a considerable increase is immediately possible in the weighting pressures acting on particular top rolls, while retaining a gradual characteristic curve iorrthe spring.

According to the invention, the downward swing of the guide arms may be limited by stops, and the stops may consist, for example, of contact lugs or the like connected to the guide arm and, if a holder is used, of an abutment mounted on an associated particular holder. it is further advisable to construct the stops in the form of anchors with supporting 'tabs against which the guide arms bear to limit their downward swing. Loops or rings may also serveras stops, which at one end engage under a hump yon the guide arm and at the other end are received in a guide in a stationary part of the drafting mechanism, for example the stirrup or holder. A further construction or the stops is one in which lugs are bent out or the guide arm, and rest against angled portions of the top-roll carrier arm. Alternatively, angled portions may be bent inwards from the top-roll carrier arm to limit the downward movement of the guide arm.

Embodiments of the invention are illustrated by way yof example in the drawings. In these drawings:

FlGURE 1 shows a top-roll carrier and weighting arm in elevation, partially in section;

FIGURE 2 shows a somewhat modified construction of a tcp-roll carrie-r arm, in elevation and partially in section;

FlGURE 3 shows a section on the line -lII-TII in FIGUR-E 2;

FIG-URE 4 shows ano-ther modified construction of a top roll carrier arm, in longitudinal section;

FIGURE 5 shows a section lon the line V-V in FIG- URE 4;

FIGURE. 6 shows a further embodiment ot the carrier arm in longitudinal section;

FGURE 7 shows a section on the line VII- VII in FlGURE 6;

FIGURE 8 shows a single guide with FiGURE 6, in plan view;

FGURE 9 shows a further embodiment of the carrier arm, partially in longitudinal section;

FIGURE l() shows a section on the 'line 'URE 9;

FIGURE ll shows a plan view of a guide arm with an additionalsupporting portion, in accordance with FIG- URE 9.

Referring -iirstl'yV to FiGURE l, a top-roll carrier arm 2, which is bent substantially into the form of a U in cross-section, is pivotally mounted on a supporting bar l lined to the machine and is held in the operating position by means of a locking device. This locking device is not shown in FlGUlE l but may be similar to Athe device shown at 103 in FiGURE 2 lwhich cc-operates with a stationary part or vthe machine, Received inside the arm Z tor longitudinal adjustment therealong are stirrups 4 and 74 with downwardly bent arms, which can be located by screws o reaching through a slot 5 in the arm 2. The stirrup 4 shown in FIGURE 1 at the side remote from the'supporting bar l comprises retaining members constructed in the form of pivot pins 7 and '77 around which are received pin-engaging means or tongues 8 o1' 'l on a holder 9. The holder 9 carries, on angled arms 9', a pivot pin 1? for the pivotal reception ot a substantially angle-shaped guide or support arm 1l, the lower` end of which is constructed in a manner known per se with a saddle-shaped support l2 to receive a pair of top rol-ls i3 indicated in chain line in the drawing (see FIG. 5). A seating 14 to 4receive one end of bias means in the formof a helical spring 15 is impressed in the upper end of the guide arm il. The other end of the helical spring i5 rests against a seating 14 pressed out of the holder 9. The holder 9* and the guide arm `11 constitute an articulated guide-arm assembly having entirely self-contained bias means in the form of the spring l5, urging the support portion l2 downwardly to press the roll i3 against the roll 16. f,

A contact lug .1S provided on angled webs in the guide arm il bears against an abutment 17 on the arm 9 of the holder 9 and thus limits the swing 4of the guide arm il about the pivot 1d.

The lholder and therefore the entire guide-arm assembly can also swing laterally parallel to the plane of the drafting field, to accommodate which movement the tongue S comprises a pressed out rib which is received in a circumferential `recess in the pivot pin 7. The tongue 78 cooperates with the pin 77 in like manner. In this manner, the twin top rol-l 13, which rests as usual, on the bottom roll 16, indicated in chain line in the drawing, can automatically align itself, bringing its axis parallel tothe axis of the bottom roll. The spring ll', with its seatings 14 and i4', also swings about the pivotV provided by the ribs.

arm in accordance X-X in FIG- In the embodiment illustrated in FIGURE l, the two stirrups 74 most adjacent to the support bar 1, comprise pivot pins 19 on which the guide or support arms 11 are mounted for pivoting only. The weighting or biasing of each of these guide arms r11 is likewise affected by bias means in the form of helical springs 15 each of which rests on the one hand against a seating pressed out of the guide arm 11' and on the other hand against a seating pressed out of the stirrup 74. A limitation of the swing of the guide arms 11 is obtained by means of parts 35 bent out of the guide arms, bearing against corresponding abutment surfaces on the stinrup 74. The slot 5 and the lixing screws 6 for the stirrups 4 and 74 are covered by a hood which is pivotally mounted on the arm 2, thus preventing the penetration of ulf into the interior of the arm 2.

In the embodiment shown in FIGURES 2 and 3, an arm 102 similar to the arm 2 receives pivot pins 22 and 122 for the direct reception of a holder 21. The holder 21 comprises pin-engaging means in the form of bearing

tongues

23 and 123 with impressed ribs which engage in recesses in the pins and permit a lateral swinging movement of the holder 21 parallel to the plane ofthe drafting lield (see particularly rib 23 and recess 24 in the pin 22 in FIG. 3). At its front end, the lholder 21 is extended and provided with an impressed seating 26 to receive bias means in the form of a helical spring 25, the other end of which rests against a seating 26 in the glide or support arm 28 which is received for pivoting about a pin 27 mounted in the holder 21. The holder 21 further comprises at its lower end, hook-shaped Contact lugs 29 which engage under a web 30 constructed in the form of an abutment face on the guide arm 2S and thus limit the swing of the guide arm 28 after the release of the arm 11.22 by the locking device 103. The guide arm 28 is constructed at its lower end with a saddle-shaped support 31 which carries the twin top roll 13. The holder 21, the guide arm 2S and the spring constitute an articulated guide arm assembly having entirely self-contained bias means and yoperable to swing laterally on the

pins

22 and 122 parallel to the plane of the drafting eld.

The two guide or support arms 28 adjacent to the supporting lbar 1 are each pivoted on a pin 32 in a holder 33 which is held against displacement in the arm 102, for example by a screw 6 in a slot 5. Each helical spring 25 (only one is shown) rests against seatings pressed out of the guide arm 28 and the holder 33. A limitation of the swing of the guide arm 28' (FIGURE 2) is effected by means of parts 34 bent out of the holder 33 (FIGURE 3) against which the guide arm 2S' bears. The mode of operation of the holder of FIGURE 2 corresponds with that o-f the one shown in FIGURE l, though no provision is made for longitudinal adjustment of the holder 21 in the arm 192.

In FIGURES 4 and 5 of the drawing there is shown a top-roll carrier arm 202 which is bent substantially into a U-shape and is closed at its two ends. The arm 202 is secured by means of a bracket 1', indicated in chain line in the drawing, to the supporting bar 1 which is xed to the machine and likewise indicated in chain line. At the top, the arm 202 comprises slots or bores 5 through which screws 6 reach to secure the

stirrups

84 and 35 in place. As in the other embodiments, these are provided with downwardly bent arms and are longitudinally adjustable along the arm 262 according to the length of the slots 5. Mounted between the downwardly bent arms of the

stirrups

84 and 85 are the pivot pins 87 and 8S to receive double-

armed guide arms

35 and 35 of resilient material which serves as the biasing means. One arm of the

guide arms

35 and 35 is arranged between the arms of the stim'up 84 and is constructed with a pin-engaging tongue in the form of half a bush at its free upper end so that it engages partly around the upper pin 87, The guide arm merely rests against the lower pin 88 of the stirrup 84. In order to reduce the friction between the upper pivot pins 87 and the guide arms 35 and 35', the latter have ribs 35 pressed 'out which rest with point or line contact on the pins 87. Similar ribs are provided at 36' to engage the pin 88, so that the arms 35 and 35', as can be seen from FIGURE 5, can swing laterally in the direction of the arrow A parallel to the plane of the drafting field. In its front end, each of the

guide arms

35 and 35 comprises a saddle-shaped support y112 to receive the twin top rolls 13, which are indicated in chain line and which co-Joperate with bottom rolls 16, likewise illustrated in chain line. In order to limit the swinging of the lower arm of the guide arms 35 and 35', holding the twin top rolls 13, a guide, in the form of a slot, is provided at 37 in the stirrup 84 and at `37 in the stirrups 85 to receive a loop or

ring

39 or 39 which reaches under a hump 38 bent out of the guide ar The length of the guides 37 and 37 should be such that, when the arm 202 is swung down towards the bottom rolls 16, the 'top rolls 13 are raised so far that the loops 39 and 39l are above the bottom end yof the guideways 37 and 37 and when the arm 2112 is locked in operative position (see FIGURE 4) the top rolls exert the pre-set pressure on the bottom rolls 15. As a result `of the resilient construction of the guide arms 35 and 35', a little or no variation biasing pressure occurs when the top rolls 13 are displaced perpendicular to the plane of the drafting held, because the spring characteristic curve is very gradual even at high pressures. The resilient guide arms `35 and 35 and the associated saddleshaped supports 112 comprise guide arm assemblies having entirely self-contained bias means and operable to swing laterally on the pins 37 and 88 parallel to the plane of the drafting field.

Should a considerable increase in the pressure be necessary in such a drafting mechanism, then, as can be seen rom FIGURE 4, an additional bias in the form of a leaf spring 4)y bent at an angle is interposed between the lower pin S3 an-d the guide arm 35. This additional spring 40 is provided, in the region of the lower pin 88, with a stamped tout trough 41 with which it engages over the corresponding rib 36 in the guide arm 35 and rests with point lor line contact on the pin S3. As a result, a considerable increase in pressure is rendered possible while retaining a perfect ability for the whole guide arm 35 to swing laterally, without the springs characteristic curve becoming steeper.

In order to secure the

guide arms

35 and 35 inside the stirrups 84 and S5, tongues 42 are pressed out of the latter so that the portion of each

guide arm

35 and 35 lying between the two pins 87 and `38 is limited as toits downward or oounterclockwise swinging movement.

Referring now to FIGURES 6 8 of the drawing, it will be seen that a helical spring 43 may also be used as additional biasing spring, which rests with one end on the free resilient arm of the guide arm l carrying the twin top roll 13 and with the other end on a supporting member 44 on the guide arm 135. This supporting member 44 is preferably made integral with the guide arm y135 and constructed at its front end in the form of a spring retainer 44 to receive the upper end of the helical spring 43. To limit the swinging Iof the lower arms of the guide arms 135 carrying the top rolls 13 outwardly bent lugs 45 are provided thereon (see particularly FIGURE 7) to bea-r against inwardly bent portion 46 of the arm 212. The mounting Aof the guide arms 135 inside the stirrup 214 and the securing of the stirrups inside the top-roll carrier and weighting arm 212 is effected in the same manner as in the embodiment shown in FIGURE 4. The guide arms i135 and their associated saddle-shaped supports comprise guide arm assemblies having entirely selfcontained bias means and operable to swing laterally on the pins of the stirrups 214 in the plane of the drafting eld.

Finally, FIGURES 9-1-1 show a further embodiment of a resilient guide arm with an additional biasing spring. In the guide arm 235, which is illustrated in the drawing at the front end of the a-rm 222, the supporting portion 144, which forms a spring retainer 144 for the helical spring 143, is integral with the guide arm 235. In contrast to the embodiments shown in FIGURES 1 to 8, an anchor 147, which reaches through slots or perforations in the guide arm 235 and the supporting portion i144, is provided for limiting the swinging movement of the guide arm 235 about the pivot. At its ends, the anchor 147 is 'provided with bent or twisted tabs 148 and 148 (see particularly FIGURE 10) which effect the said limitation by bearing against the edges of the slots in the guide arm 235 and supporting portion 144. The guide arm 235, the support portion 144, the spring '143, the anchor 147 and the saddle-shaped supports comprise a guide arm assembly having entirely self-contained biasmeans and operable to swing laterally on the pins of the carrier arm 222 in the plane of the drafting field.

ln the middle guide arm 335 shown in FIGURE 9, the supporting portion 49 is constructed in the form of an additional part and is substantially U-shaped, and -rails Sil bent out of the arms of the supporting portion 49 bear from the rea-r against the part of the guide arm 335 lying between the pivots 171 and 172, while a web 51, which joins the two arms of the supporting portion 49, has its end face, which is curved towards the pin 171, in edge contact with the upper portion of the guide arm 335. The web 51 lies in a plane passing through the centre axis of the upper pivot 17-1 so that the additional helical spring only acts on the lower arm of the guide arm 335.

The spring -143 bears at one end on the lower end of the guide arm 335 and at the other end on a seating on the supporting portion 49. As in the foremost guide arm illustrated in FIGURE 9, the swinging movement is limited by an anchor 247 with bent or twisted tabs. The guide arm 335, the support portion 49', the spring and anchor 247, and the saddle-shaped supports comprise a guide arm assembly having entirely self-contained bias means and operable to swing laterally on the pins of the carrier arm 222 in the plane of the drafting field.

The arm 222 may be held in the operating position by means of a locking device 53 (see FIGURE 9) which is known per se, and is actuated by means of an operating lever 52. The arm 222 is released from the operating position by pivoting the lever 52 counteroloclcwise on its pivot to permit the depending linli of the locking device 53 to move downwardly so that it may be disengaged from the hook-shaped part which is mounted on the apparatus which carries the lower rolls 16. The length of the operating lever permits the upper rolls to be forced against the lower rolls with a very high loading pressure. After the locking device has been released, it can be swung up and if necessary secured to its upper position. Similar devices are shown in FIGS. 4 and 6. In FIGS. 2. and 3, the locking device 1t3 may be lreleased for displacement out of hooking engagement with a retainer similar to that shown in FIG. 9. To this end, the operating Alever is displaced 180 counterclockwise until it abuts the free end of the arm 102. Further downward pressure on the lever forces the upper rolls 13 downwardly against the lower rol-ls .16 with suthcient pressure to unhook the device 103 and permit it to be pivoted out of the path of the retainer, for example by the part projecting upwardly above the pinned connection to the operating lever and arm 102. Thereupon, the carrier arm 102 may be pivoted upwardly on the bar 1.

In order to limit the swinging of the

guide arms

235 and 335 towards the rear, tongues 142 may -be pressed out of the stirrups and rest either directly against the port-ion `of the guide arm lying betwen the pins as shown with arm 235 or, if the supporting portion 49 separate from the guide arm 335 is used, against the rail 50 (FIGURE 9).

The middle stirrup and the one adjacent to the bracket may be adjustable in the slot in the arm 22,2, as a result of which the mutual distance between the top yrolls 13 may be varied. A further stirrup may also be received inside the arrn 222, depending on the length of the slot and the practical requirements.

It is to be understood that the invention is not restricted to the precise constructional details set forth.

Y We claim:

l. Textile drafting lmechanism comprising a series of top and bottom rolls defining therebetween a drafting field, a top roll carrier arm, pin means rigidly mounted in said carrier arm, |and a guide arm assembly for one top roll having at one end portion pin-engaging means mounted on said pin means and supporting said guide arm assembly for lateral swinging movement parallel to said drafting field and restricting said pin-engaging means against pivotal movement on said pin means perpendicular to said drafting field, said guide arm assembly including top roll supports at the-opposite end portion thereof mounted 'for swinging movement relative to said pinengaging means perpendicular to said drafting field to displace the top roll into and out of engagement with .the associated bottom roll, and said guide arm assembly including entirely self-contained bias means to urge said top roll supports toward the associated bottom roll.

2. Textile drafting mechanism according to claim l including stop means for limiting displacement by said bias irneans of said guide arm assembly adjacent said top roll supports.

3. Textile drafting mechanism according to claim l wherein said pin means comprises a pair of spaced -pins disposed substantially parallel to the roll axes of said top and bottom rolls, and having their axes aligned in a plane transverse to the drafting field, said pin-engaging means comprising at least one tongue wrapped around said pin means and having at least one impressed rib engaging said pin -means to allord said :lateral swinging movement parallel to said drafting eld.

4. Textile drafting mechanism according to claim 1 including a stirrup adjustably mounted on -said carrier arm and mounting said pin means therein for adjustment longitudinally of said carrier ar-m.

5. Textile drafting mechanism according to claim 1 wherein said bias means comprises a substantially flat resilient arm portion mounting said pin-engaging means at one end position and said top supports at the opposite end portion.

6. Textile drafting mechanism according to claim 5, including means for limiting the flexure of said resilient arm portion.

7. Textile drafting mechanism according to claim 5, including a spring element, a first seat for said spring element on said guide arm assembly adjacent said pin-engaging means and an opposed seat for said spring clement on said resilient arm portion adjacent said top roll supports.

8. Textile drafting mechanism according to claim 7 wherein said spring consists of a leaf spring element.

9. Textile drafting mechanism according to claim 7 `wherein said spring consists of a helical spring element.

10. Textile drafting mechanism according to claim 9, wherein said first seat comprises a rigid arm projecting outwardly lfrom said guide arm assembly adjacent said pin-engaging elements to ovcrlie said resilient arm, said helical spring being compressed between said rigid arm and said resilient arm to supplement the bias of said resilient arm. Y

ll. Textile drafting mechanism according to claim l wherein said lguide arm assembly comprises a holder having said pin-engaging means thereon, and a support arm pivotally mounted on said holder for pivotal movement about an axis parallel to said top roll and mounting said top roll supports thereon, said bias means being conlined under stress between said holder and said support arm.

l2. Textile drafting mechanism according to claim 11 wherein said bias meansV comprises a helical spring seated at one end on said holder and at the other end on said support arm to bias `said Itop roll supports toward the associated bottom roll.

13. Textile drafting mechanism according to claim 1 wherein the guide arm assembly comprises relatively movable parts, said pin-engaging elements being mounted on one of said parts and said top` roll supports being mounted on another of said parts, said bias means being confined under stress between said parts.

UNITED STATES PATENTS Hohloch Apr. 20, 1954 Da-usch Nov. 6, 1954 Dausch June 26, 1956 Anderson Aug. 14, 1956 Dausch Jan. 14, 1958 FOREIGN PATENTS Switzerland Jan. 16, 1954

Claims

1. TEXTILE DRAFTING MECHANISM COMPRISING A SERIES OF TOP AND BOTTOM ROLLS DEFINING THEREBETWEEN A DRAFTING FIELD, A TOP ROLL CARRIER ARM, PIN MEANS RIGIDLY MOUNTED IN SAID CARRIER ARM, AND A GUIDE ARM ASSEMNBLY FOR ONE TOP ROLL HAVING AT ONE END PORTION PIN-ENGAGING MEANS MOUNTED ON SAID PIN MEANS AND SUPPORTING SAID GUIDE ARM ASSEMBLY FOR LATERAL SWINGING MOVEMENT PARALLEL TO SAID DRAFTING FIELD AND RESTRICTING SAID PIN-ENGAGING MEANS AGAINST PIVOTAL MOVEMENT ON SAID PIN MEANS PERPENDICULAR TO SAID DRAFTING FIELD, SAID GUIDE ARM ASSEMBLY INCLUDING TOP ROLL SUPPORTS AT THE OPPOSITE END PORTION THEREOF MOUNTED FOR SWINGING MOVEMENT RELATIVE TO SAID PINENGAGING MEANS PERPENDICULAR TO SAID DRAFTING FIELD TO DISPLACE THE TOP ROLL INTO AND OUT OF ENGAGEMENT WITH THE ASSOCIATED BOTTOM ROLL, AND SAID GUIDE ARMS ASSEMBLY INCLUDING ENTIRELY SELF-CONTAINED BIAS MEANS TO URGE SAID TOP ROLL SUPPORTS TOWARD THE ASSOCIATED BOTTOM ROLL.