US3732596A

US3732596A - Top roll loading system for drafting units

Info

Publication number: US3732596A
Application number: US00153608A
Authority: US
Inventors: S Staneff
Original assignee: Industriewerk Schaeffler OHG
Current assignee: INA Waelzlager Schaeffler OHG
Priority date: 1971-06-16
Filing date: 1971-06-16
Publication date: 1973-05-15
Anticipated expiration: 1990-05-15

Abstract

A guide arm of a top roll loading system of a drafting unit is pivotally mounted on a bracket, with the pivot thereof positioned a substantial distance below and rearwardly of the plane of all of the drafting rolls so that yieldable force applied to the guide arm is transmitted to the top rolls in an inclined downward and forward direction, as is particularly desirable where the back or feed top roll is offset rearwardly of the back or feed bottom roll of the drafting unit. Also, a novel compound linkage connects a yieldable force means to a latch arm pivoted on the guide arm and is so designed that a compression spring or a pressurized pneumatic bag or tube may be used alternatively as the yieldable force means therefor by a simple interchange of parts.

Description

United States Patent (1 1 Staneff [54] TOP ROLL LOADING SYSTEM FOR DRAFTING UNITS [75] Inventor: Stefan Staneff, Herzongenaurach,

Germany [73] Assignee: Industriewerk Schaeffler, OI-IG,

Herzongenaur'ach, Germany [22] Filed: June 16, 1971 [21] Appl. No.: 153,608

[52] US. Cl ..l9/267, 19/295 [51] Int. Cl. ..D0lh 5/46 [58] Field Of seillch ..l9/266, 267, 261, 19/295, 258

[56] References Cited UNITED STATES PATENTS 840,779 H1907 Libby ..19/26I 3,310,848 3/1967 Stahlecker et al ..l9/267 3,568,258 3/1971 Schiltknecht et al ..I9/295 1 3,732,596 May 15, 1973 FOREIGN PATENTS OR APPLICATIONS 732,939 6/l955 Great Britain l9/258 Primary ExaminerDorsey Newton Attorney- Warley L. Parrott ct al.

[57] ABSTRACT A guide arm of a top roll loading system of a drafting unit is pivotally mounted on a bracket, with the pivot thereof positioned a substantial distance below and rearwardly of the plane of all of the drafting rolls so that yieldable force applied to the guide arm is transmitted to the top rolls in an inclined downward and forward direction, as is particularly desirable where the back or feed top roll is offset rearwardly of the back or feed bottom roll of the drafting unit. Also, a novel compound linkage connects a yieldable force means to a latch arm pivoted on the guide arm and is so designed that a compression spring or a pressurized pneumatic bag or tube may be used alternatively as the yieldable force means therefor by a simple interchangc of parts.

15 Claims, 9 Drawing Figures PATEME MAY 1 5 ms sum 1 0r 4 PATENTEI] HAY] SE73 SHEET 3 BF 4 TOP ROLL LOADING SYSTEM FOR DRAFTING UNITS This invention relates to drafting units for roving frames, spinning frames, and the like, and is particularly concerned with loading or weighting means for the top rolls of such drafting units.

Heretofore, such drafting units generally have been provided with a loading system including a pivoted guide arm carrying front and rear'saddles to which the usual holders or support blocks for the top drafting rolls are adjustably secured for varying the spacing be tween adjacent top rolls. Various forms of releasable pressure means have been proposed heretofore for applying downward pressure to the pivoted guide arms of such loading systems to, in turn, load the top rolls while they occupy operative positions over the bottom drafting rolls.

As far as is known, at least those top roll loading systems which have not been equipped with individual springs or other individual pressure devices for each top roll heretofore, have been so constructed as to apply pressure to the top rolls only in a downward di rection substantially perpendicular to the mean path of travel of the textile fibers being drafted through the drafting units. However, there are instances in which it is desirable to apply such pressure in a direction inclined forwardly and downwardly, as for example, when the loading system is used with a drafting unit of the type having at least the rearmost or back feed roll of its top rolls offset rearwardly of the corresponding bottom feed roll. Also, it is desirable that the effective pressure being applied to each top drafting roll is adjustable without necessarily providing an individual pressure device or spring means for each top roll.

It is therefore an object of this invention to provide a loading system for the top rolls of a drafting system including a pivoted guide arm and means for applying a generally downward yielding force to the guide am, but wherein the arm is so mounted that such force is transmitted to the top rolls in an inclined downward and forward direction, and additionally wherein the guide arm has a rear saddle for the top feed roll pivotally connected thereto, with a front saddle for the intermediate and front top roll being pivotally connected to the rear saddle, in such a manner that the pivots are selectively positionable to vary the moment of force applied to each top drafting roll.

It is another object of this invention to provide a top roll loading system of the character described including a support bracket stationarily mounted rearwardly of the drafting rolls, and wherein the rear portion of the guide arm is pivotally connected to the bracket for movement about an axis spaced a substantial distance below the mean plane of the path of travel of the textile fibers being drafted through the drafting unit so that, when a yieldable force is applied to the guide arm tending to pivot the same downwardly about its axis, the pressure is transmitted to the top rolls in an inclined downward and forward direction.

Still another object of this invention is to provide a top roll loading system of the character last described including improved means for transmitting pressure or force from a yieldable force means to the guide arm and comprising a compound linkage having an upper lever and a lower lever pivotally mounted on the aforementioned bracket and whose proximal portions overlap each other with the upper portion of the lower lever positioned forwardly of the lower portion of the upper lever. A forwardly projecting downwardly facing cam surface is provided on the upper lever above its pivot point, and a latch arm is pivotally mounted on the guide arm on an axis above and rearwardly of the cam surface and has a locking element which is movable with the latch arm into and out of engagement with the cam surface. The yieldable force means urges the lower lever in one direction about its pivot so that its upper portion engages and urges the upper lever in the opposite direction about its pivot whereby the cam surface is biased forwardly and downwardly, and the relationship of the locking element and the pivot of the latch am is such that, when the locking element is engaging the cam surface, it biases the guide arm downwardly thereby loading the top rolls of the drafting unit. The latch arm may be pivoted upwardly relative to the guide arm so that the top rolls may be readily relieved of the load thereon, and the guide arm then may be swung upwardly and rearwardly to an inoperative position with the guide arm.

Some of the objects of the invention having been stated, other objects will appear as the description proceeds when taken in connection with the accompanying drawings, in which FIG. 1 is a side elevation of a drafting unit, partially in section, showing the improved top roll loading system in association therewith;

FIG. 2 is a top plan view of the apparatus shown in FIG. 1;

FIG. 3 is an enlarged longitudinal vertical sectional view through the drafting unit and the loading system with the bottom drafting rolls being shown in broken lines, and wherein the assembly of parts is shown in a different position from that of FIG. 1 for purposes of clarity;

FIG. 4 is a fragmentary vertical sectional view taken substantially along line 4-4 in FIG. 3;

FIG. 5 is a fragmentary vertical sectional view taken substantially along line 5-5 in FIG. 3;

FIG. 6 is a fragmentary rear elevation of the guide arm and associated supporting means therefor looking in the general direction of the arrow indicated at 6 in FIG. 3;

FIG. 7 is an exploded perspective view of the front and rear saddles, associated top roll holders and one of the top drafting rolls, removed from the guide arm of the loading system;

FIG. 8 is a fragmentary vertical sectional view similar to the right-hand portion of FIG. 3, but wherein the various parts shown in FIG. 8 occupy positions corresponding to FIG. 1, and showing the loading system arranged to accommodate pneumatic pressure to serve as its yieldable force means as an alternative to the compression spring means of FIG. 3; and

FIG. 9 is a fragmentary vertical sectional view taken substantially along line 99 in FIG. 8.

The loading system of this invention, although not limited thereto, is especially useful in association with drafting units of the type having one or more top rolls which are offset rearwardly of respective bottom drive rolls. Therefore, referring more specifically to the drawings, the drafting unit shown in FIGS. 1-3 includes three spaced bottom drafting rolls, namely, a bottom back or feed roll 11, a bottom intermediate roll 12, and a bottom front or delivery roll 13. As preferred, the

bottom rolls are shown in the form of fluted rolls.

Top drafting rolls

11a, 12a, 13a are provided adjacent the respective

bottom drafting rolls

11, 12, 13, and to aid in controlling the fibers being drafted, the bottom feed roll 11 may be offset upwardly of the plane of

bottom rolls

12, 13. As preferred, the top rolls are shown in the form of cushion rolls. Although the three top rolls may be disposed in a substantially common plane extending through the axes thereof, top feed roll 11a is offset rearwardly of bottom feed roll 11 to form a nip therewith which is spaced angularly rearwardly of the apex of feed roll 11 with respect to the mean plane of the path of travel or draft path" of the fibrous textile material T through the drafting unit. Suitable endless draft aprons 14, 14a may engage the

respective rolls

12, 12a with the forward portions of aprons 14, 14a engaging suitable cradle nose members 15, 15a adjacent the nip of

delivery rolls

13, 13a to aid further in control of the fibers being drafted.

The improved loading or weighting system of this invention comprises a guide arm of hollow construction and which includes an elongate forward portion or body 20a of inverted substantially U-shaped crosssectional configuration and having a rear downwardly extending portion 20b thereon which straddles a stationarily mounted, hollow support bracket 21. The two legs of the downwardly extending portion 20b of guide arm 20 are pivotally connected to the respective opposite side walls of bracket 21 by substantially axially aligned pivot pins 22. It is important to note that, although the pivot axis of guide arm 20 is shown in FIG. 1 positioned above the level of all of the drafting rolls 1 1-13, 1 1a-13a when the top rolls Ila-13a occupy the solid line, operative, positioned of FIG. 1, such axis, represented by pivot pins 22, is positioned a substantial distance below the mean plane of the draft path through the drafting unit, which plane is represented by the broken line P in FIG. 1. Stated in another way, the axis of guide arm 20 is spaced a substantial distance from the substantially common plane of top rolls Ila-13a and is located on the opposite side of such plane from that of the guide arm body 20a which carries the top rolls Ila-13a and, also, the pivot axis of guide arm 20 is spaced a substantial distance rearwardly of the drafting rolls 11-13, Ila-13a. Preferably, the guide arm pivot axis is spaced below the plane of all of the drafting rolls.

Thus, with the top rolls occupying the operative position shown in solid lines in FIG. 1, when a predetermined yieldable force is applied to guide arm 20, by means to be later described, and thus urges guide arm 20 in a counterclockwise direction in FIGS. 1 and 3, such force is transmitted about the axis of pivot pins 22 and thus to the top drafting rolls'1la-13a in an inclined forward and downward direction with respect to the mean plane of the draft path of the textile material T passing through the drafting unit. It is apparent that, by applying the force to the top feed roll 11a in this manner, the pressure is more efiective at the nip of rolls 11, 11a than would be the case if the pressure was directed downwardly thereat in a direction substantially perpendicular of the mean plane of the draft path or in a direction inclined downwardly and rearwardly with respect to the mean plane of the draft path as has been the case heretofore. In instances in which the nip of the feed rolls is located closely above the rearmost surface of the bottom feed roll it is important that the pressure applied to the top feed roll has a component of forward thrust or force as opposed to having only a downward or downward and rearward component of thrust. Otherwise, the top feed roll might have the effect of a wedge against the bottom feed roll, or in the event of the top roll having a yieldable cover or cot thereon, the top roll might slip downwardly relative to the bottom feed roll.

Suitable means is provided for removably securing bracket 21 on an elongate shaft 25 which may extend past the rear portions of a plurality of drafting units of the type heretofore described and which are usually provided on a single roving or spinning machine. To this end, and is preferred, the rear portions of the side walls of bracket 21 are each provided with a slot 21a separating the upper and lower portions thereof, and opposite ends of upper and lower clamping bars 21b, 210 are connected to or extend through the bracket side walls. Cam surfaces 21b on the proximal edge portions of

clamping bars

21b, 21c, and adjacent the elongate shaft 25, engage corresponding cam surfaces on a clamping block or cam block 21e extending between the two

clamping bars

21b, 21c. Clamping block 21c has an arcuate inner surface which is substantially of the same configuration as and engages the outer surface of the elongate shaft 25. A screw 21f loosely penetrates the lower clamping bar 210 and threadedly penetrates the upper clamping bar 21b. Thus, it is apparent that the screw may be tightened to draw the opposing upper and lower portions of the bracket side walls toward each other while, at the same time, the cam surfaces 2ld on

clamping bars

21b, 21c engage the cam surfaces of clamping block 21e to cam the same against and tightly secure the bracket 21 in the desired position on the elongate shaft 25.

Referring to FIGS. 1, 3 and 4, it will be observed that the elongate body 20a of guide arm 20 includes depending spaced apart side walls or flanges 200 between which the upper portions of rear and

front saddles

26, 27 are positioned. The rear portion of rear saddle 26 (FIG. 7) is substantially U-shaped in cross-section and the bridging lower wall thereof forms a slotted guideway 26a for receiving therein a bolt 30 which adjustably secures thereto a rear holder or support block 11b for top delivery roll 11a. As shown in FIGS. l-3, as is conventional, top rolls 11a, 12a, are journaled on shafts releasably mounted in the corresponding holders or support blocks 11b, 12b, 13b.

The side walls or flanges of rear saddle 26 extend for wardly beyond the slotted guideway26a and have the upper portions of the side walls of front saddle 27 positioned therebetween. Front saddle 27 also is substantially U-shaped in cross-section and the bridging lower wall thereof also forms a slotted guideway 27a for receiving bolts 32, 33 therein to adjustably secure thereto the respective intermediate and front holders or support blocks 12b, 13b for the respective intermediate and

delivery top rolls

12a, 13a. To aid an operator in determining the desired adjusted spacing of the

top drafting rolls

11a, 12a, 13a, the lower portions of the side walls or flanges of

saddles

26, 27, below the side walls of guide arm body 20a, may bear suitable. graduated indicia thereon, as shown in FIG. 1. Such indicia may be in the form of a metric scale.

The

saddles

26, 27 are pivotally mounted in such a manner as to facilitate changing the moment arm ratios thereof with respect to each other and with respect to guide arm thereby varying the amount of pressure applied to each top drafting roll Ila-13a without changing the positions of the saddles relative to each other and relative to guide arm 20. To this end, the front upper portions of the guide arm side walls 20c and the side walls of rear saddle 26 are provided with longitudinally extending rows of aligned, spaced, holes or bores 35, and a first saddle pivot pin 36 passes through an opposing set of the bores 35 in guide arm side wall 20c and rear saddle 26 to pivotally mount rear saddle 26 on guide arm 20. Pivot pin 36 may be selectively positioned in the sets of aligned bores, three sets of which are shown in FIGS. 1, 3 and 7, to thereby vary the position of the pivot axis of rear saddle 26 relative to guide arm 20. Opposite ends of the pivot pin 36 may extend outwardly beyond guide arm side walls 200 and may be suitably recessed for receiving thereon suitable snap rings 35a (FIG. 4), preferably of resilient material, for removably securing the pivot pin 36 in the desired position.

The proximal overlapping portions of the side walls of

saddles

26, 27 also are provided with longitudinally extending rows of aligned, spaced holes or bores 40 therethrough, and a second saddle pivot pin 41 passes through an opposing set of bores 40 in

saddles

26, 27 to pivotally connect the medial portion of front saddle 27 to a forward portion of rear saddle 26. Although the sets of bores 40 are positioned in such proximity to each other that they are in open communication with each other, it is apparent that the scalloped upper and lower edges of the slots thus formed from the bores 40 constitute, to all intents and purposes, definition of the aligned holes or bores 40. Thus, it is apparent that pivot pin 41 may be selectively positioned in the sets of aligned bores 40 to thereby vary the position of the pivot axis of front saddle 27 relative to rear saddle 26 and guide arm to thereby vary the effective pressure applied to each top drafting roll Ila-13a. It is thus seen that the first and second pivot pins 36, 41 are selectively positionable along guide arm 20 and rear saddle 26, respectively, for pivotally connecting rear saddle 26 to guide arm 20 and for pivotally connecting front saddle 27 to rear saddle 26 to vary the pivot axes of the rear and front saddles 26, 27 without changing the position of the saddles relative to each other and relative to guide arm 20.

Utilizing an actual apparatus constructed according to the invention, different top roll pressures have been obtained by varying the positions of pivot pins 36, 41 longitudinally of the

saddles

26, 27 without shifting them longitudinally of guide arm 20 and without changing the amount of yieldable force applied to guide arm 20. For example, with the axes of top intermediate roll 12a and top feed roll 11a spaced rearwardly from the axis of top delivery roll 47 millimeters (mm) and 108 mm, respectively, pivot pin 36 (FIG. 3) was positioned in the frontmost set of holes 35, and pivot pin 41 was positioned in the second set of holes from the front as in FIG. 3. This resulted in loads of l3, l5 and 18 kilograms being applied to the respective

top rolls

11a, 12a, 13a. Simply by changing the position of pivot pin 41 to the frontmost set of holes 40, this changed the loads on

top rolls

11a, 12a, 13a to l8, l0 and 20 kilograms, respectively.

As a further example, the roll spacing was changed so that the axes of rolls 12a, 11a were spaced 70 mm and 144 mm, respectively, rearwardly of the axis of top delivery roll 13a, and pivot pins 36, 41 were positioned in the rearmost sets of

holes

35, 40. This resulted in loads of l7, l5 and 20 kilograms being applied to the respective

top rolls

11a, 12a, 13a.

Novel means are provided for applying pressure to guide arm 20 while it occupys the lowered, operative position shown in solid lines in FIGS. 1 and 3, and for releasing such pressure and retaining guide arm 20 and the top drafting rolls carried thereby in the raised, inoperative, position shown in broken lines in FIG. 1. In this regard, two embodiments of yieldable force means are shown in FIGS. 3 and 5 and FIGS. 8 and 9, respectively. The first embodiment utilizes a mechanical spring means for the yieldable force means, and the second embodiment utilizes a pneumatic bag or tube for the yieldable force means. Either embodiment of the yieldable force means may be used with the same support bracket 21, guide arm 20 and the parts carried thereby, and with essentially the same releasable yieldable force transmitting means, to be later described, with the exception of interchanging a relatively few parts to convert one embodiment to the other. In fact, if desired, one or more of the drafting units of a particular textile machine may be equipped with top roll loading systems of this invention utilizing the mechanical spring type of yieldable force means, while one or more others of the drafting units of the same textile machine may be equipped with top roll loading systems of this invention utilizing the pneumatic type of yieldable force means. To facilitate interchangeability of the two forms of yieldable force means, it is preferred that support shaft 25 is of tubular form and is slotted along its length, preferably by providing a slot or opening 25a (FIGS. 3 and 6) through its lower wall portion corresponding to each bracket 21, although support shaft 25 may be solid when utilizing the mechanical spring means of the first embodiment of the yieldable force means with the top roll loading system.

The first embodiment of the yieldable force means comprises a coiled compression spring 45 (FIG. 3) which encircles a plunger 45a whose rear portion is guide for longitudinal movement in an upstanding spring abutment 21g positioned between the rear lower portions of the side walls of bracket 21. Spring abutment 21g may be formed integral with a bottom wall portion 21h extending between and integral with the side walls of bracket 21.

The rear end of spring 45 bears against spring abutment 21g and the front end thereof bears against an enlarged portion 45b of plunger 45a. The front end of plunger 450 may be bifurcated and provided with a wedge-shaped forward portion 45c which bears against the grooved lower leg of a substantially vertically extending lower lever 50 which is a component of the releasable yieldable force transmitting means. A medial portion of lower lever 50 is pivotally mounted on a pivot pin 500 whose opposing end portions extend through suitable holes provided in the side walls of bracket 21 and may be retained therein by suitable snap rings 50b (FIGS. 1 and 5). The upper portion of lower lever 50 (FIG. 3) overlaps the proximal lower portion of an upper lever 51, the upper portion of lower lever 50 being positioned forwardly of the lower portion of upper lever 51 and preferably having a roller or follower 50c journaled thereon for engaging the front surface of the lower portion of upper lever 51. A me dial portion of upper lever 51 is also pivotally mounted on a pivot pin 51a which may be removably mounted in the side walls of bracket 21. Upper lever 51 is provided with a forwardly projecting downwardly facing cam surface 51b which is positioned above the pivot point or pin 51a of upper lever 51, and the upper portion of lever 51 is provided with an upper guide surface 510 thereon which extends upwardly and rearwardly from the front extremity of cam surface 51b and whose rear portion terminates adjacent shoulder means 21i formed by the side walls of bracket 21, which side walls straddle

levers

50, 51.

The yieldable force transmitting means further comprises a latch arm broadly designated at 54. Latch arm 54 comprises an elongate forward or handle portion 54a which overlies the body 20a of guide arm 20. Latch arm 54 is preferably of inverted substantially U-shaped cross-section and is provided with a downwardly projecting rear portion 54b which loosely penetrates the upper wall of guide arm 20 and is pivotally mounted on a pivot pin 54c extending between and positioned in the side walls or flanges 200 of guide arm 20. It is to be noted that pivot pin 540 is positioned above and rearwardly of the cam surface 51b of upper lever 51. Positioned between the side walls of the lower portion 54b of latch arm 54 is a locking element which preferably takes the form of a roller 54d rotatably mounted in the latch arm 54. Roller 54d is movable with latch arm 54 about pivot pin 54c and the relationship of roller 54d and pivot pin 54c is such that, when roller 54d is engaging cam surface 51b, the handle portion 54a of latch arm 54 is in engagement with the upper wall of the body 20a of guide arm 20 and the roller 51b will have moved the upper lever 51 in a clockwise direction in FIG. 4 against follower 50c and in opposition to compression spring 45 thereby applying a predetermined downward pressure to the body 20a of guide arm 20 for loading the top rolls of the drafting unit. On the other hand, when the latch arm 54 is pivoted upwardly relative to guide arm 20, roller 54d moves forwardly and upwardly out of engagement with cam surface 51b, thus releasing guide arm 20 and permitting cam surface 51b to move downwardly and forwardly a relatively short distance to the extent permitted by engagement of the lower portion of upper lever 51 with the front surface of support shaft 25.

In this regard, since counterclockwise movement of upper lever 51 is limited by engagement thereof with shaft 25 when guide arm 20 is released, the effective pressure to be transmitted to guide arm 20 when roller 54d is engaging cam surface 51d may be varied by adjustably varying the angular position of bracket 21 about support shaft 25 and relative to

bottom drafting roller

11, 12, 13. Thus, the overall load on the

top rolls

11a, 12a, 13a may be adjusted to some extent without necessarily changing spring 45 or the position of either

saddle pivot pin

36 or 41. It is to be noted that the upwardly projecting front edge portion of bottom wall 21h of bracket 21 also serves to limit forward movement of the lower portion of lower lever 50, as is desirable to facilitate installing bracket 21 on shaft 25, and removing bracket 21 from shaft 25, with guide arm 20 thereon and with latch arm 54 mounted on guide arm 20. In fact, if desired, the upwardly projecting front portion of the lower wall 21h of bracket 21 may be so positioned as to be engaged by lever 50 at the same time as or before its roller 50c pushes lever 51 against shaft 25 upon roller 54d being moved out of engagement with cam surface 51b,

To permit movement of latch arm 54 relative to guide arm 20 for applying pressure to and releasing pressure from guide arm 20 and also facilitate utilizing the latch lever 54 for raising and lowering guide arm 20, a torsion spring 54c is coiled about pivot pin 54c and has one leg thereof engaging the lower surface of the top wall of body 20a of guide arm 20. The other leg of torsion spring 54e engages the upper edge of an abutment 54f integral with and projecting inwardly from a forward portion of one of the side walls of the portion 54b of latch arm 54.

Thus, with the latch arm 54 occupying the operative position shown in FIG. 3, an operator may pivot the handle portion 54a upwardly relative to latch arm 21) until roller 54d moves out of engagement with cam surface Slb of upper lever 51, whereupon torsion spring 54e will urge the body of guide arm 20 upwardly against latch arm 54. During the upward pivotal movement of guide arm 20 and latch arm 54, follower or roller 54d may ride upon the arcuate guide surface 51c of upper lever 51. Upon the guide arm 20 and latch arm 54 being moved upwardly a predetermined distance to the inoperative position shown in broken lines in FIG. 1, for example, an abutment means 51g (FIG. 3) on the opposing side walls of the relatively short lower portion 54b of latch arm 54 may b moved into engagement with the shoulders Zli on the upper portions of the side walls of bracket 21 so as to support the guide arm 20 and its

top rolls

11a, 12a, 13a in the raised position independently of spring 45 and the compound linkage embodied in levers 51B, 51. When the guide arm is to be returned to the lowered or operative position, the operator may apply downward pressure to the body 20a of guide arm 20 as latch arm 54 is pivoted upwardly relative to guide arm 20 to thereby release the abutment means 51b from the shoulders 21i of bracket 21, whereupon the roller 54b may again be guided upon the guide surface 51c on upper lever 51 as the guide arm 20 is returned to the fully lowered or operative position and until roller 54d is again moved into engagement with cam surface 51b.

In most instances, pivot pin 41 is likely to be so positioned that, when the

top rolls

11a, 12a, 13a are not being supported by bottom rolls 11-13 or the stock passing therebetween, the rear portion of front saddle 27 tends to fall away from the guideway 26a of rear saddle 26, as when guide arm 20 occupies raised, inoperative, position or is being moved toward or away from the latter position. To avoid such condition without interferring with that movement of front saddle 27 necessary to its intended function, it will be observed in FIGS. 3 and '7 that spring means, in the form of a relatively light, small, inverted substantially U-shaped, leaf spring 27b, has one of its legs suitably attached to the rear portion of guideway 27a of front saddle 27. The other, rear, leg of spring 27b overlies and may rest upon the front portion of guideway 26a of rear saddle 26. Thus, rear saddle 26 may support the rear portion of front saddle 27 while guide arm 20 is raised, but

spring 27b permits front saddle 2'7 to move in either direction about its pivot pin 41 while guide arm 20 is being moved into operative position and while it occupies operative position. Spring 27b should be light so that it will have very little, if any, noticeable effect on the pressure being applied to the

top rolls

11a, 12a, 13a

if spring 27b happens to come into contact with rear saddle 27 while guide arms occupies operative position.

The second embodiment of the yieldable force means shown in FIGS. 8 and 9 requires only very slight modification of the top roll loading system as described heretofore. Therefore, those parts of the loading system shown in FIGS. 8 and 9 which correspond to like parts shown in FIGS. 1-7 will bear the same reference characters, where applicable.

The second embodiment of the yieldable force means comprises an elongate pliable air bag or tube 55 closed at its opposite ends and positioned within tubular support shaft 25. One end of pliable tube 55 has a fitting 55a thereon (FIG. 9) for connecting the same to a conduit 55b extending from a suitably controlled source of compressed air, not shown. Fitting 55a may be in the form of a check valve through which compressed air may be introduced into tube 55 by means of a portable air hose, not shown, if desired. Within shaft 25, pliable tube 55 is engaged by the flanged upper portion of a plunger 550 which loosely penetrates the corresponding slot a heretofore described. In this second embodiment, the yieldable force transmitting means is modified with respect to the first embodiment to the extent that the substantially straight lower lever 50 of FIG. 4 is replaced by a substantially L-shaped lever or bell crank 60. Conveniently, lever 60 may be pivotally mounted on the same pivot pin 50a as that used in the first embodiment for mounting lever 50 on bracket 21. As is the case with respect to lever 50, the upper portion of lever 60 extends upwardly in overlapping relation to and forwardly of the lower portion of the upper lever 51 and has a roller 60c mounted therein for engaging the front surface of the lower portion of upper lever 51. However, the lower arm of lower lever 60 extends rearwardly beneath tubular support shaft 25 and its rear upper portion is engaged by the lower end of plunger 55c. Thus, the pneumatic pressure in pliable tube 55 urges plunger 55c against lever 60, thus tending to move the same in a clockwise direction in FIG. 8 to apply a rearward force to the upper portion of lever 60 against the lower portion of lever 51. It is apparent that the lever 51 operates in the same manner when utilizing the second embodiment of the yieldable force means shown in FIGS. 8 and 9 as is the case when utilizing the first embodiment of the yieldable force means which is best shown in FIG. 3. Accordingly, a further description thereof is deemed unnecessary.

In the drawings and specification, there have been set forth preferred embodiments of the invention and, although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation.

That which is claimed is:

1. A loading system for a drafting unit having a series of bottom drafting rolls and a series of top drafting rolls defining a draft path for textile fibers being drafted therebetween, said loading system comprising a guide arm having a forward portion normally overlying said drafting rolls, a rear saddle pivotally connected to said forward portion of said guide arm and including a first guideway on a rear portion thereof for adjustably receiving a holder for a feed roll of said series of top rolls, a front saddle pivotally connected to a forward portion of said rear saddle and including a second guideway for adjustably receiving at least one other holder for an other roll of said series of top rolls, first and second pivot pins selectively positionable longitudinally along said guide arm and said rear saddle, respectively, for pivotally connecting said rear saddle to said guide arm and for pivotally connecting said front saddle to said rear saddle to vary the pivot axes of said rear and front saddles, means including a bracket stationarily mounted rearwardly of said drafting rolls pivotally supporting a rear portion of said guide arm on a pivot axis spaced a substantial distance below and rearwardly of the plane of all of the drafting rolls and positioned on the opposite side of the drafting rolls from that of said pivot pins, and releasable force applying means for applying a generally downward pressure to said guide arm such that the location of said pivot axis of said guide arm causes the pressure on said guide arm to be transmitted to the top rolls in a downward and forward direction, and whereby the force applied to the top rolls may be varied by varying the pivot axes of said saddles, said releasable force applying means comprising yieldable force means carried by said bracket, a lever pivotally mounted on said bracket and having a downwardly facing cam surface on its front portion above its pivot, means operatively connecting said lever to said yieldable force means so that said cam surface thereon is biased forwardly and downwardly, a latch arm having a rear portion thereof pivotally connected to said guide arm on an axis above and rearwardly of said cam sur face of said lever, a locking roller carried by said latch arm and movable therewith into and out of engagement with said cam surface, and the distance from the pivot axis of said latch arm to said locking roller being such that said locking roller displaces said cam surface upwardly in opposition to said yieldable force means when said top drafting rolls are in loading relation to said bottom drafting rolls.

2. A loading system according to claim 1, wherein said guide arm and said rear saddle are provided with means for receiving said first pivot pin and arranged to vary the position of the pivot axis of said rear saddle longitudinally of said guide arm.

3. A loading system according to claim 1, wherein said rear saddle and said front saddle are provided with means for receiving said second pin therein and arranged to vary the position of the pivot axis of said front saddle longitudinally of said rear saddle.

4. A loading system according to claim 1, wherein said first and second guideways of the respective rear and front saddles are disposed in proximal nonoverlapping relationship, and a leaf spring attached to a rear portion of said second guideway and overlying a front portion of said first guideway to limit downward movement of the rear portion of said front saddle relative to said rear saddle whenever said guide arm is swung upwardly manually to lift the top drafting rolls away from the bottom drafting rolls.

5. A loading system for a drafting unit for drafting textile fibers, said drafting unit having a series of top drafting rolls and a series of bottom drafting rolls; said loading system comprising a guide arm, means mounting said top rolls on a forward portion of said guide arm, a support shaft extending generally parallel with said drafting rolls and spaced rearwardly from said drafting unit, a support bracket secured on said shaft and to which a rear portion of said guide arm is pivotally connected, compound linkage including an upper lever and a lower lever pivotally mounted on said bracket and having proximal overlapping portions with the upper portion of said lower lever positioned forwardly of the lower portion of said upper lever, a forwardly projecting downwardly facing cam surface on said upper lever above its pivot point, yieldable force means urging said lower lever in one direction about its pivot so that its upper portion engages and urges said upper lever in the opposite direction about its pivot whereby said cam surface is biased forwardly and downwardly, a latch arm pivotally mounted on said guide arm on an axis above and rearwardly of said cam surface, a locking element carried by said latch arm and movable therewith into and out of engagement with said cam surface, and the relationship of said locking element and the pivot of said latch arm being such that, when said locking element is engaging said cam surface, it biases said guide arm downwardly thereby loading the top rolls of the drafting unit and whereby, by pivoting said latch arm upwardly relative to said guide arm, the top rolls may be relieved of the load thereon and said guide arm may be pivoted upwardly and rearwardly about its pivot.

6. A loading system according to claim 5, wherein the pivot axis of said guide arm is located at a lower portion of said bracket substantially below the plane of the drafting rolls whereby yielding force is transmitted to the top rolls from said yieldable force means through said guide arm in a downward and forward direction.

7. A loading system according to claim 5, wherein said bottom rolls include a bottom feed roll and said top rolls include a top feed roll which, when occupying an operative position, has its rotational axis spaced rearwardly of and above the rotational axis of said bottom feed roll, and wherein the pivot axis of said guide arm is located at a lower portion of said bracket substantially below the mean plane of the path of the fibers through the drafting unit whereby yielding force is transmitted to the top rolls from said yieldable force means through said guide arm in a downward and forward direction to thereby urge said top feed roll downwardly and forwardly toward its nip with said bottom feed roll.

8. A loading system according to claim 5, wherein said yieldable force means comprises a spring carried by said bracket.

9. A loading system according to claim 5, wherein said yieldable force means comprises a spring-loaded plunger movably supported by said bracket and engaging and applying a forward force to said lower lever below its pivot.

10. A loading system according to claim 5, wherein said yieldable force means comprises a coiled spring arranged to apply forward force to said lower. lever below its pivot point, means limiting the extent of rearward movement of the lower portion of said upper lever and thus limiting the extent of forward and downward movement of said cam surface when said locking element is out of engagement with said cam surface, and means adjustably securing said bracket on said support shaft for angular adjustment of said bracket about the axis of said support shaft to thereby permit adjustment of the position of said cam surface relative to said bottom drafting rolls whereby the load to be applied to said top rolls when said locking element is engaging said cam surface may be adjusted by angular adjustment of said bracket.

11. A loading system according to claim 5, wherein said support shaft is tubular, and wherein said yieldable force means comprises a yieldable pneumatic tube in said support shaft adapted to contain compressed air therein, and a plunger engaging said tube, loosely penetrating the wall of said shaft, and engaging said lower lever to apply a rearward force to its upper portion against said upper lever.

12. A loading system according to claim 5, wherein said latch arm includes a handle portion overlying said guide arm, and spring means between said latch arm and said guide arm arranged to apply a lifting force to said guide arm when said latch arm is raised and said locking element is out of engagement with said cam surface.

13. A loading system according to claim 12, wherein said bracket is provided with shoulder means thereon rearwardly of said upper lever, and abutment means on said latch arm engageable with said shoulder means when said latch arm is raised a predetermined distance relative to said cam surface on said upper lever to thereby support said guide arm and its top rolls in a raised position.

14. A loading system according to claim 13, wherein said upper lever is provided with an upper guide surface thereon extending rearwardly from said cam surface to a point adjacent said shoulder means for engagement by said locking element and arranged to guide said locking element between said cam surface and said shoulder means during raising and lowering of said latch arm and said guide arm.

15. A loading system for a drafting unit having a series of bottom drafting rolls and a series of top drafting rolls defining a draft path for textile fibers being drafted therebetween, said loading system comprising a guide arm having a forward portion normally overlying said drafting rolls, a rear saddle pivotally connected to said forward portion of said guide arm and including a first guideway on a rear portion thereof for adjustably receiving a holder for a feed roll of said series of top rolls, a front saddle pivotally connected to a forward portion of said rear saddle and including'a second guideway for adjustably receiving at least one other holder for another roll of said series of top rolls, first and second pivot pins selectively positionable longitudinally along said guide arm and said rear saddle, respectively, for pivotally connecting said rear saddle to said guide arm and for pivotally connecting said front saddle to said rear saddle to vary the pivot axes of said rear and front saddles, a support shaft extending generally parallel with said drafting rolls and spaced rearwardly of said drafting unit, a bracket secured on said shaft and to which a rear portion of said guide arm is pivotally connected for movement on a pivot axis spaced a substantial distance below and rearwardly the plane of all of the drafting rolls and positioned on the opposite side of the drafting rolls from that of said pivot pins, compound linkage including an upper lever and a lower lever pivotally mounted on said bracket and having proximal overlapping portions with the upper portion of said lower lever positioned forwardly of the lower portion of said upper lever, a forwardly projecting downwardly facing cam surface on said upper lever above its pivot point, yieldable force means urging said lower lever in one direction about its pivot so that its upper portion engages and urges said upper lever in the opposite direction about its pivot whereby said cam arm downwardly thereby loading the top rolls of the drafting unit whereby the location of said pivot axis of said guide arm causes the pressure on said guide arm to be transmitted to the top rolls in a downward and forward direction, and whereby the force applied to the top rolls may be varied by varying the pivot axes of said saddles.

* i i t

Claims

1. A loading system for a drafting unit having a series of bottom drafting rolls and a series of top drafting rolls defining a draft path for textile fibers being drafted therebetween, said loading system comprising a guide arm having a forward portion normally overlying said drafting rolls, a rear saddle pivotally connected to said forward portion of said guide arm and including a first guideway on a rear portion thereof for adjustably receiving a holder for a feed roll of said series of top rolls, a front saddle pivotally connected to a forward portion of said rear saddle and including a second guideway for adjustably receiving at least one other holder for another roll of said series of top rolls, first and second pivot pins selectively positionable longitudinally along said guide arm and said rear saddle, respectively, for pivotally connecting said rear saddle to said guide arm and for pivotally connecting said front saddle to said rear saddle to vary the pivot axes of said rear and front saddles, means including a bracket stationarily mounted rearwardly of said drafting rolls pivotally supporting a rear portion of said guide arm on a pivot axis spaced a substantial distance below and rearwardly of the plane of all of the drafting rolls and positioned on the opposite side of the drafting rolls from that of said pivot pins, and releasable force applying means for applying a generally downward pressure to said guide arm such that the location of said pivot axis of said guide arm causes the pressure on said guide arm to be transmitted to the top rolls in a downward and forward direction, and whereby the force applied to the top rolls may be varied by varying the pivot axes of said saddles, said releasable force applying means comprising yieldable force means carried by said bracket, a lever pivotally mounted on said bracket and having a downwardly facing cam surface on its front portion above its pivot, means operatively connecting said lever to said yieldable force means so that said cam surface thereon is biased forwardly and downwardly, a latch arm having a rear portion thereof pivotally connected to said guide arm on an axis above and rearwardly of said cam surface of said lever, a locking roller carried by said latch arm and movable therewith into and out of engagement with said cam surface, and the distance from the pivot axis of said latch arm to said locking roller being such that said locking roller displaces said cam surface upwardly in opposition to said yieldable force means when said top drafting rolls are in loading relation to said bottom drafting rolls.

4. A loading system according to claim 1, wherein said first and second guideways of the respective rear and front saddles are disposed in proximal non-overlapping relationship, and a leaf spring attached to a rear portion of said second guideway and overlying a front portion of said first guideway to limit downward movement of the rear portion of said front saddle relative to said rear saddle whenever said guide arm is swung upwardly manually to lift the top drafting rolls away from the bottom drafting rolls.

10. A loading system according to claim 5, wherein said yieldable force means comprises a coiled spring arranged to apply forward force to said lower lever below its pivot point, means limiting the extent of rearward movement of the lower portion of said upper lever and thus limiting the extent of forward and downward movement of said cam surface when said locking element is out of engagement with said cam surface, and means adjustably securing said bracket on said support shaft for angular adjustment of said bracket about the axis of said support shaft to thereby permit adjustment of the position of said cam surface relative to said bottom drafting rolls whereby the load to be applied to said top rolls when said locking element is engaging said cam surface may be adjusted by angular adjustment of said bracket.

15. A loading system for a drafting unit having a series of bottom drafting rolls and a series of top drafting rolls defining a draft path for textile fibers being drafted therebetween, said loading system comprising a guide arm having a forward portion normally overlying said drafting rolls, a rear saddle pivotally connected to said forward portion of said guide arm and including a first guideway on a rear portion thereof for adjustably receiving a holder for a feed roll of said series of top rolls, a front saddle pivotally connected to a forward portion of said rear saddle and including a second guideway for adjustably receiving at least one other holder for another roll of said series of top rolls, first and second pivot pins selectively positionable longitudinally along said guide arm and said rear saddle, respectively, for pivotally connecting said rear saddle to said guide arm and for pivotally connecting said front saddle to said rear saddle to vary the pivot axes of said rear and front saddles, a support shaft extending generally parallel with said drafting rolls and spaced rearwardly of said drafting unit, a bracket secured on said shaft and to which a rear portion of said guide arm is pivotally connected for movement on a pivot axis spaced a substantial distance below and rearwardly the plane of all of the drafting rolls and positioned on the opposite side of the drafting rolls from that of said pivot pins, compound linkage including an upper lever and a lower lever pivotally mounted on said bracket and having proximal overlapping portions with the upper portion of said lower lever positioned forwardly of the lower portion of said upper lever, a forwardly projecting downwardly facing cam surface on said upper lever above its pivot point, yieldable Force means urging said lower lever in one direction about its pivot so that its upper portion engages and urges said upper lever in the opposite direction about its pivot whereby said cam surface is biased forwardly and downwardly, a latch arm pivotally mounted on said guide arm on an axis above and rearwardly of said cam surface, a locking element carried by said latch arm and movable therewith into and out of engagement with said cam surface, and the relationship of said locking element and the pivot of said latch arm being such that, when said locking element is engaging said cam surface, it biases said guide arm downwardly thereby loading the top rolls of the drafting unit whereby the location of said pivot axis of said guide arm causes the pressure on said guide arm to be transmitted to the top rolls in a downward and forward direction, and whereby the force applied to the top rolls may be varied by varying the pivot axes of said saddles.