US783183A - Let-off mechanism for looms. - Google Patents

Description

PATENTED FEB. 21, 1905.

0. H. DRAPER.

LET-OFF MECHANISM FOR LOOMS.

APPLIOATION FILED NOV. 18, 1904.

Patented February 21, 1905.

FFIQE.

PATENT CLARE H. DRAPER, OF HOPEDALE, MASSACHUSETTS, ASSlGNOR TO DRAPER COMPANY, OF HOPEDALE, MASSACHUSETTS, A CORPO- RATION OF MAINE.

LET-OFF MECHANISM FOR LOOIVIS.

SPECIFICATION forming part of Letters Patent No. 783,183, dated February 21, 1905.

Application filed November 18, 1904- Serial No. 233,260. v 7

To all? whmn it may concern Be it known that LCLARE H. DRAPER, a citizen of the United States, and a resident of Hopedale, county of Worcester, State of Massachusetts, have invented an Improvement in Let-Off Mechanism for Looms, of which the following description, in connection with the accompanyingdrawings, is aspecification, like characters on the drawings representing like parts.

In the well-known Bartlett let-01f motion the whip-roll or warp-guide is moved or rocked downward at each pick by the tension of the warp, a suitable connection setting a pawl (cooperating with a ratchet through which the warp-beam is rotated) in such manner that a greater or less number of ratchet-teeth will be delivered when the pawl is moved forward to a fixed point on its operating stroke. The greater the warp tension the larger the number of teeth which will be taken by the pawl when set, and a correspondingly greater delivery of the warp will be effected, the pawl being moved to a fixed point at each stroke by a connection between the pawl-carrier and a moving part of the lay. This let-off motion is defective because of the increased strain upon the warp due to the greater movement of the whip-roll when the beam is nearly empty, for as the diameter of the yarn mass on the beam decreases a greater number of ratchet-teeth must be included in the stroke of the pawl to compensate for such decrease, and this greater movement of the whip-roll requires greater power to effect the same. Such increased strain or tension on the warp results in narrower cloth, causes thin places at the time of filling-changing, and increases warp breakage. In United States Patent to Draper and Roper, No. 647,815, dated April- 17, 1900, these objectionable features were overcome by the employment of novel means controlled by the warp tension and the diameter of the yarn mass on the beam to determine the starting-point of each stroke of the pawl. Such means includeda compound pawl-carrier with a relatively movable connection for the members thereof, one of said members being moved in setting the pawl by means governed by the warp tension, while the position ofthe connection between the members of the pawlcarrier was determined by a controlling device dependent upon the diameter of the yarn mass on the beam. This let-ofi' mechanism has been highly satisfactory in operation; but my present invention has for its object the production of a simpler form of let-off mechanism possessing the various advantageous features of such patented structure and free from the objections of the Bartlett type of let-off.

- I have in the present embodiment of my invention eliminated the compound pawl-carrier and the follower which cooperates with the periphery of the yarn mass on the beam, together with the connecting devices between the follower and the compound pawl-carrier, the starting-point of each stroke of the pawl being determined herein by means acting wholly through the whip-roll, so that such starting-point is located in conformity with the combined action of the warp tension and the diameter of the yarn mass on the beam.

Figure 1 is a right-hand side elevation of a loom with let-off mechanism embodying one form of my present invention applied thereto. Fig. 2 is a detail viewed from the opposite side of the loom of the rocking support for the whip-roll and some of the adjacent parts to. be described; and Fig. 3 is a rear view, centrally broken out, of the whip-roll and adjacent parts.

The warp-beam B, having an attached large gear l5,the drivingshaftB carrying-in practice a pinion (not shown) in mesh with the beam-gear B and having loosely mounted upon it the ratchet B, the friction clamp or brake F to cooperate with the ratchet-hub, the speed-reducing gearing inclosed within the casing Gr, forming a part thereof and connected by hub g with the shaft B and the arms 5 and g, slidably connected with'a fixed stud E on the loom side, may be and are all substantially as in United States Patent of Roper, No. 744,941, said patent being based upon the prior patent, No. 647,815, hereinbefore referred to.

Herein the let-off pawl d", which cooper ates with and operates the ratchet B is mounted on a pawl-carrier 1, loosely mounted to rock upon the shaft B adjacent the ratchet and having a depending arm 2 pivotally con' d on the lay-sword A substantially as in Patent No. 744,941 referred to. The forward beat of the lay acts through the link to impart the feed'or operating stroke to the pawl d and moving it to a fixed point on each stroke. Brackets 3 on the loom sides above the warp-beam support a transverse horizontal rock-shaft 4, having secured to it by set screws 5 Fig. 3, upturned arms 5, provided at or near their upper ends with bearings for the journals w of the whip-roll or warp-guide W, over which the warp w passes from the beam to the lease-rods L and harnesses H, Fig. 1. On the end of the shaft adjacent the right-hand side of the loom, as herein shown, an upturned arm 6 is adjustably secured by a'set-screw 7, said arm having an elongated longitudinal slot 8, in which is adjustably secured a stud 9, on which is pivoted the upper end of a link 10, its lower end being pivotally connected at 11 with the pawlcarrier 1 between the pawl and the shaft 13*, on which said pawl-carrier rocks. Adjacent the whip-roll-supporting arm 5 near theup-' turned arm 6 the hub of an arm 12 is mount spring S is secured at one end to the loom.

side and at its other end it is attached to a downwardly and rearward] y extended arm 17, secured to the rock-shaft 4 by a set-screw 18 Fig.2.

It will be manifest from an inspection of the drawings that the warp tension will rock the whip roll forward at each pick, and the greater the tension of the warp the greater will be the amplitude of angular movement of the whip-roll as it rocks on the shaft 4 as a fulcrum. Consequently the arm 6 will be correspondingly rocked to a greater or less extent in conformitywith the warp tension, and the link 10 will depress the pawl-carrier 1 more or less to determine or fix the starting-point for each operating stroke of the let-ofl' pawl 6?. The greater the angle between the portions 11; of the warp leading from the yarn mass N on the beam of thewhip-roll and from the latter forward at w the nearer will the resultant of the forces acting upon the whipthan at the later unwinding. 'ity of. variation in the warp angle should be compensated for in order to obviate any re roll approach its fulcrumviz., the .rockshaft 4and for a given warp tension the less will be the amplitude of the angular movement of said whip-roll. Such angle will be greatest when the beam is full, and,conversely, it gradually diminishes as the diameter of such yarn mass decreases. As the upper side w of the warp angle remains substantially fixed, while the opposite side w (formed by the warp leading from the beam to the whiproll) changes its position, it follows that the resultant of the forces acting upon the whiproll to rock it will gradually move away from the fulcrum on which the whip-roll rocks. Consequently as the diameter of the yarn mass on the beam decreases the whiproll will be rocked a greater distance,but without increasing the strain upon the warp at each pick, inasmuch as the increased leverage effects the desired increased movement without any additional warp strain, and such augmented amplitude of movement of the whiproll will act through arm 6 and link 10 to of .warp let off from the beam. As a matter of :fact, the rate of change in the position of the part w of the warp varies from full to empty beam for a uniform. rate of decrease in the diameter of the yarn mass that is to say, the rate of change in the angular position of the part '90 will be very much greater per inch, say, of 'diametrical decrease in the yarn mass when the unwinding of the beam begins than it will i be when the beam is nearly empty, or, in -other words, the .angle inclosed by the portions' w w of the warp decreases at a faster rate during the early unwinding of a beam This irregularquirement for adjustment of the let-off during the complete unwinding of a beam, and such 1 compensation 1S attained by the connectlon between the whip-roll and the pawl-carrier, such connection comprising the arm 6 and link 10. It will be manifest that the more nearly the arm6 approaches the horizontal as itis moved downward by the forward movement of the whip-roll the greater will be the movement of the pawl to'the starting-point of its effective stroke, and such stroke will belonger. The setting stroke for the pawl will be less, however, for a given angular movement of the arm 6 when the latter is at or about the position shown in Fig. 1 than it will be for the same angular movement of the arm when nearer horizontal position. In other words, the rate of variation of the setting stroke does not increase until a very considerable increase in the regular movement of the arm 6 1S eflected', and this increase in angular minimum.

movement of said arm is not effected until the unwinding has progressed quite far, so the increase in the rate of variation of the setting stroke of the pawl does not occur until the rate of change in the position of the part w of the warp has reached substantially its Thus the rapid rate of change in the one is automatically compensated for by the slow rate of variation of the other, and vice versa, eliminating the necessity for manual adjustment during the unwinding of the beam.

The theory of operation may be stated thus: Supposing the warp pull or tension to be uniform, the whip-roll should be swung through 4 increasingly greater arcs as the yarn mass decreases, and the arm 6 should correspondingly be moved through greater angles to thereby impart by degrees a lengthening stroke to the pawl (Z as the beam empties. An increasing angular movement of the beam should result, letting off the proper length of yarn at each pawl-stroke, increasing little by little as the diameter of the yarn mass decreases; but if the angle between 10 and w decreases at a more rapid rate at the beginning of the unwinding, as is the fact, the corresponding arcs of movement of the whip-roll would at first appear to be so long that there would be a tendency to impart too long a stroke to the pawl, which would result in letting off the yarn too rapidly, presupposing the rate of increase in the pawl-strokes to be regular. Atthe beginning ofthe unwinding. however, the movements of the whip-roll are not great enough to impart sufiicient angular movement to the arm 6 to effect any practical increase of the pawl-stroke, while later as the beam empties the increasing arcs of movement of the whip-roll impart greater angular movements to the arm 6 and the pawl-strokes are gradually lengthened therebyat a more rapid rate as the rate of decrease of the angle between w and w diminishes. The desired compensation is thus effected automatically and the yarn is neither let off too rapidly at first nor too slowly at the last. I am thus enabled to secure substantially the same warp tension during each pick from the full to the empty beam with very simple and direct-acting means, the warp tension and the diameter of the yarn mass onthe beam acting conjointly and wholly through the whip-roll to determine the starting-point of each stroke of the pawl.

The adjusting-screw 14 is provided with a head PI by which the screw can be readily turned with the aid of a wrench or similar tool to change the angle of the arms 5 with relation to the arm 6, enlargement of the angle serving to shorten the feed-stroke of the pawl while decrease of the angle lengthens the stroke. When such adjustment is to be made, the setscrews 5 are loosened and the whip-roll is moved with or against the pull of the warp,

according to the direction in which the screw no change in relation between the pawl-carrier and arm 6. If a change in the latter relation is desired, it can be effected by adjustment of the stud 9 in the slot 8.

My invention is not restricted to the precise construction and arrangement herein shown and described, as the same may be modified in various particulars by those skilled in the art without departing from the spirit and scope of my invention.

Having fully described my invention, what I claim as new, and desire to secure by Letters Patent, is-

1. In let-off mechanism for looms, a warpbeam, means to rotate it, including a ratchet and pawl, an actuating device to move the pawl to a fixed point at each operating stroke, a rocking whip-rollthe amplitude of whose angular movement is controlled conjointly by the warp tension and the diameter of the yarn mass on the beam, to maintain a substantially uniform warp tension throughout the unwinding, and means intermediate said whip-roll and pawl to determine the starting-point of each stroke of the pawl inconformity with the angular movement of the whip-roll.

2. In let-ofi' mechanism for looms, a warpbeam, means to rotate it, including a ratchet and pawl, a pawl-carrier, an actuating device therefor to move the pawl to a fixed point at each operating stroke, a rocking whip-roll the amplitude of whose angular movement is controlled conjointly by the warp tension and the diameter of the yarn mass on the beam, and means intermediate the whip-roll and pawlcarrier and directly connected with the latter to determine the starting-point of each stroke of the pawl in conformity with the angular movement of the whip-roll.

3. In let-off mechanism for looms, a warpbeam, means to rotate it; including a ratchet and pawl, a'pawl-carrier, an actuating device therefor to move the pawl to a fixed point at each operating stroke, a rocking whip-roll the amplitude of whose angular movement is controlled conjointly by the warp tension and the diameter of the yarn mass on the beam, means intermediate the whip-roll and pawl-carrier and directly connected with the latter to determine the starting-point of each stroke of the pawl in conformity with the angular movement of the whip-roll, and an adjusting device for said means.

4. In let-off mechanism for looms, a warpbeam, means to rotate it, including a ratchet and pawl, an actuating device to move the pawl to a fixed point at each operating stroke, upturned arms fulcrumed above the beam, a whip-roll mounted on said arms and adapted to be rocked by or through the warp, the amp'litudeof angular movement of the whip-roll being controlled conjointly hy the warp tension and the diameter of the yarn mass on the 1 is turned, the adjustment so made makingbeam, to maintain a substantially uniform warp tension throughout the unwinding, and means intermediate the whip-roll and pawl to determine thestarting-point of each stroke of the latter in conformity with the angular movement of the whip-roll.

5. In let-off mechanism for looms, a warpbeam, means to rotate it, including a ratchet and pawl, an actuatingdevice to move the pawl to a fixed point at each operating stroke, a rock-shaft mounted above the warp-beam and having rigidly attached upturned arms, a whip-roll mounted in said arms and adapted to be rocked about the shaft as a center, the angular movement of the whip-roll varying in accordance with the warp tension and gradually increasing by or through the decrease of the diameter of the yarn mass on the beam, and means intermediate the whip-roll and pawl to fix the starting-point of the pawl-stroke according to the amplitude of the corresponding angular movement of the whip-roll.

6. In let-off mechanism for looms, a warpbeam, means to rotate it, including a ratchet and pawl, an actuating device to move the pawl to a fixed point at each operating stroke, a rock-shaft mounted above the warp-beam and having rigidly attached upturned arms, a whip-roll mounted in said arms and adapted to be rocked about the shaft as a center, the angular movement of the whip-roll varying in accordance with the Warp tension and grad ually increasing by or through the decrease of the diameter of the yarn mass on the beam, an arm mounted on the shaft and operatively connected with the pawl, and means to vary v the angle between said arm and the whip-rollsupporting arms, the connection between the adjustable arm and the pawl determining the starting-point of the pawl-stroke in conformity with the angular movement of the whip-roll;

7.- In let-off mechanism for looms, a warpbeam, means to rotate it, including a ratchet and pawl, a pawl-carrier, an actuating device therefor to move the pawl to a fixed point at each operating stroke, a rock-shaft mounted above the beam and having attached upturned arms, a whip-roll mounted in the latter and adapted to be rocked about the shaft as a center, the amplitude of angular movement of the whip-roll varying with variations in warp tension and having a gradual increase by or through the decrease of the diameter of the yarn mass on the beam, an arm angularlyadjustable on the rock-shaft, and a link pivotally connecting said arm and the pawl-carrier, to fix the starting-point of the latter for each operating stroke of the pawl in conformity with the corresponding angular movement of the whip-roll. I

8. In let-off mechanism for looms. a warpbeam, means to rotate it, including a ratchet and pawl, an actuating device to move the pawl to a fixed point at each pick, a rocking whiproll, and means acting wholly throughsaid whip-roll to determine the starting-point of each stroke of the pawl in conformity with the combined action of the warp tension and the diameter of the yarn mass on the beam, to thereby maintain a substantially uniform warp tension throughout the unwinding.

9'. In let-off mechanism for looms, a warpbeam, means to rotate it, including a ratchet and pawl, actuating means for the latter, including a rocking whip-roll, and means depending on the angle of the warp between the beam and the whip-roll to effect increased movement of the whip-roll while the tension of the warp remains substantially uniform.

10. In let-off mechanism for looms, a warpbeam, means to rotate it, a movable whip-roll, to govern the amplitude of angular movement of the beam, and means to vary the movement of the whip-roll by or through a change in the position of the plane of the warp between the whip-roll and the beam while the tension of the warp remains substantially uniform.

11. In let-otf mechanism for looms, a warpbeam, means to rotate it, including a ratchet and a pawl, actuating means for the latter, including a rocking whip-roll, and means governed by or through the movement of the whiproll to compensate for irregular variation in the angular position of the warpbetween the full and the empty beam and thereby prevent variation in warp tension.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

CLARE H. DRAPER.

Witnesses:

GEORGE OTIS DRAPER, ERNEST W. WVooD.

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