US2058127A - Let-off mechanism for looms - Google Patents

Description

Oct. 20, 1936.- QDBROWN 2,058,127

' LET-OFF MECHANISM FOR LOOMS- Filed May 1, 1936 INVENTOR.

C'AEL D. 5Eow/v BY I @M {M ATTORNEY.

Patented Oct. 20, 1936 PATENT OFFICE LET-OFF MECHANISM FOR LOOMS Carl D. Brown, Hopedale, Mass, assignor to Draper Corporation, Hopedale, Mass., a corporation of Maine Application May 1, 1936, Serial No. 77,402

Claims. (Cl. 139-100) This invention relates to looms and more particularly to means for controlling the'rate at which the warp sheet is let off from the warp beam as the weaving progresses.

Let-off mechanism has been provided in which the rotation of the warp beam is controlled by means operating in timed relation to the other mechanism of the loom, and under control of the various devices for governing the rate of rotation of the warp beam in accordance with the tension of the warp sheet. Such let-off mechanisms have usually been operated only once during each complete reciprocation of the lay, that is, once for each pick. I 4

Under some conditions the action of the takeup and of the shedding mechanism combine to produce such a tension on the warp sheet that it becomes desirable that the let-off operate more frequently than once for each pick. v r 2 An object of the present invention, accordingly is to provide an improved let-off mechanism with simple and efficient controlling devices for causing the let-off operation a plurality of times during each reciprocation of the lay. As illus-' trated, the present invention provides a single operating member for causing the let-off mechanism operation to take place twice during each reciprocation of the lay.

In the drawing,

Figure 1 is a view in side elevation of a loom showing a let-01f mechanism embodying a preferred form of the present invention;

Figure 2 is a detail view showing in full and dotted lines the positions which the parts of the let-off mechanism assume during the forward movement of the sword; and,

Figure 3 is a detail view similar to Figure 2 showing the positions of the parts during return movement of the sword.

The parts of the loom as illustrated may be supported between loomsides 2 which may be of any usual form and construction. A reed 4 is carried by a lay 6 which is mounted upon swords 8. The swords 8 are mounted for reciprocation toward and away from the front of the loom by a crank l0 and a pitman l2 as is usual in machines of this type.

The warp sheet passes from a warp beam, indicated generally at l4, over a whip roll l6, through harnesses l8, andthrough the reed 4. The cloth as it is woven may be taken up by any conventional form of take-up mechanism now well known in the art. The take-up mechanism and the harness operating mechanismare not de- 55; scribed herein since they are not essential to a complete understanding of the present invennun.

The warp beam I4 is provided at one end with a head 20 having gear teeth out therein which cooperate with the teeth of a pinion (not shown). The pinion is fixed upon a shaft 24 which is driven by internal gearing contained within a housing 26 which is operated by a ratchet wheel 28. The parts referred to just above are not described in detail herein since they are described and claimed in United States Patent No. 647,815, granted April 1'7, 1900 to W. F. Draper and C. F. Roper to which reference may be had for a more detailed description.

The whip roll I6 is mounted in arms 30 on a rock shaft 32 journalled. in the loom frame. The rock shaft 32 is provided with an arm 34 which is pivoted at 36 to one end of a link 38. The other end of the link 38 passes through an opening formed in a bracket 40 secured to the loomside 2. A spring 42 surrounds the link 38 and is interposed between the bracket 40 anda collar on the link to yieldingly urge the whip roll l6 against the Warp sheet. The lower end of the link 38 is bent over and engages the front of a lug 44 on a lever 48 which is pivoted at 46 to the bracket 40. lever 48 extends downwardly and is pivotally connected by a suitable stud (not shown) to an oscillating pawl carrier 50. The pawl carrier 50, as shown, is in the form of a lever fulcrumed on the shaft 24. The above mentioned pivotal connection may be positioned and controlled as in the above mentioned patent to Draper et al. A spring 52 is connected at one end to the lever 48 and at its other end to an arm 54 fixed to the bracket 40.

By this construction, it will readily be understood that the spring 52 serves yieldingly to urge the lever 48 in a clockwise direction and thus to urge the pawl carrier 50 in a counter-clockwise direction. Movement of the pawl carrier 50 in a counter-clockwise direction serves to draw the pawl 56 over the teeth 58 of the ratchet wheel 28 and to position the pawl 50 for an operating stroke. This counter-clockwise or return movement of the pawl 50 is limited by the bent end of the link 38. That is, the spring 52 will move the lever 48 in a clockwise direction until the lug contacts with the bent line of the link 38, the position of which is controlled by the tension of the warp sheet. 1 l

I have provided mechanism operating in timed relation to the lay for imparting to the pawl carrier two operating strokes during the interval required for the lay to make one complete recip- The rocation. A preferred form of this mechanism will now be described.

The lower end of the pawl carrier lever 56 is pivotally connected at 66 to one end of a substantially horizontal rod 62. The other end of this rod 62 is pivotally connected at 64 to the lower end of a lever 66 which is fulcrumed at 68 on a. bracket 16 fastened to the loomside 2. An actuating member 12 is secured to the sword 8 by a machine screw 13, and is provided with a pair of outwardly projecting lugs 14, 16. The lugs are arranged on opposite sides of the lever 66 with the lower lug Hi located below the fulcrum 68 of the lever 66 and the upper lug located above the fulcrum 68. When the lay 6 moves'in the direction indicated by the arrow in Figure 2, the lug 14 engages the lever 66 and rocks it in a clockwise direction. When the lay 6 moves in the opposite direction, as indicated by the arrow in Figure 3, the upper lug 16 engages the lever 66 and rocks it in a clockwise direction. The spring 52 between these movements of the lever 66 has operated to move the lever 66 and the pawl carrier 56 connected thereto in a counter-clockwise direction as described above. It is to be noted that the lugs l4, 16 on the actuating member 12 are so arranged that they engage the lever 66 to move it in a clockwise direction only during part of the reciprocating movement of the lay 6. This is accomplished by so spacing the lugs 14, 76 away from the lever 66 that there is lost motion between these parts.

Referring now to Figure 2, the parts shown in full lines are in the position they assume when the lay 6 is in its extreme forwardposition. At this time the lug "i4 is in engagement with the lever 66. The lug 16 at this time does not engage the lever 66. When the lay 6 begins its return movement, the spring 52 operates to return the lever 66 and thepawl carrier 56 connected thereto to starting position. After this return movement has been completed, and the parts are in the positionshown in dotted lines in Figure 2, the upper lug 16, on continued return or rearward movement of the lay 6, contacts with the lever 66 to impart a second clockwise movement to the lever 66 and the pawl carrier 56.

Movement of the lever 66 in a clockwise direction continues until the parts occupy the positions shown in full lines in Figure 3. At this time, the pawl carrier 56 has been advanced to the end of its operating stroke and the lug 16 is still in engagement with the lever and the lug 14 is out of engagement therewith. When the lay 6 is moved from this back position toward its mid position as shown in Figure 1, the spring 52 will operate to move the lever 66 and the pawl carrier 56 in a counter-clockwise direction to return the pawl carrier 56 and the lever 66 to the position shown in dotted lines in Figure 3. Dur ing the movement of the parts from the dotted line position shown in Figure 2 to the dotted line position in Figure 3, the lower lug M has not been in engagement with the lever 66. When the lay 6 continues its forward movement, the lug 14 will come into engagement with the lever 66 and will rock the lever and the pawl carrier 56 in a clockwise direction to operate the let-off mechanism.

Although the invention has been described in detail, it may be well for a clearer understanding of the invention, to review the operationof the machine, briefly. Beginning the cycle of operation of the lay 6 at the extreme back position as shown in full lines in Figure 3, the lay 6 is moved forwardly to the full line position shown in Figure 2. During the first portion of this movement, the spring 52 operates to move the lever 66 in a counter-clockwise direction to return the pawl carrier 56 to the dotted line position shown in Figure 3. After the pawl carrier has been returned to this position, the lug 14 engages the lever 66 and rotates it in a clockwise direction to impart to the pawl carrier 56 its operating stroke to rotate the beam and. let off the warp sheet. The parts continue this movement until the lay 6 reaches its extreme forward position, as shown in full lines in Figure 2. The lay 6 then begins its return movement and the spring 52 operates to return the lever 66 and the pawl carrier 56 connected thereto to the position shown in dotted lines in Fig. 2. The upper lug then engages the lever ,66 to impart an operating stroke to the pawl carrier 56. This return movement is continued until the parts are returned to the position shown in full lines in Figure 3, thus completi ng the reciprocation of the lay 6. It is apparent that the let-off mechanism is positively operated twice during a single reciprocation of the lay 6.

Although the invention has been described with particular'reference to the mechanism disclosed in the drawing, it is evident that the invention is not limited thereto, and that other mechanism could be employed if so desired.

Having'thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. In a loom having a frame, a reciprocating lay and a warp let-off mechanism, said let-off mechanism including gearing operated by a single ratchet wheel for controlling the advance of a warp sheet, an oscillating pawl carrier for moving said ratchet wheel, an actuating member fixed with respect to said lay, and a singlemember movably mounted on the loom frame and arranged to be engaged by said actuating member for imparting two complete oscillations to said pawl carrier for each complete oscillation of the lay;

2. In a loom having a frame, a reciprocating lay and a warp let-off mechanism, said mechanism including gearing operated by a single ratchet wheel for controlling the advance of a warp sheet, an oscillating pawl carrier for moving said ratchet wheel, an actuating member fixed with respect to said lay, and a lever fulcrumed to the loom frame and connected to said pawl carrier, said lever being arranged to be engaged by said actuating member to receive two complete oscillations from said actuating member during a single reciprocation of the lay.

3. In a loom, a reciprocating lay and a warp let-off mechanism, said let-off mechanism including gearing operated by a single ratchet wheel for controlling the advance of a warp sheet, an oscillating pawl carrier for moving said ratchet wheel, an actuating member reciprocating with the lay, said member being provided with a pair of projections, and a single means connected to saidpawl carrier arranged to be engaged by said projections to impart two complete oscillations to said pawl carrier during a single reciprocation of the lay.

4. In a loom having a frame, a reciprocating lay and a warp let-off mechanism, said let-off mechanism including gearing operated by a single ratchet wheel for controlling the advance of a warp sheet, an oscillating pawl carrier for moving said ratchet wheel, an actuating member fixed with respect to the lay and provided with a pair of projecting lugs, a lever fulcrumed to the loom frame and connected to said pawl carrier, one of said lugs being positioned to engage the lever above the fulcrum of said lever and the other lug being positioned to engage the lever below said fulcrum, whereby one of said lugs will engage said lever on movement of the lay in one direction to impart an operating movement to said pawl carrier and the other of said lugs to engage said lever to impart an operating movement to said pawl carrier during movement of the lay in the opposite direction, and yielding means for returning the pawl carrier to its initial position between operating movements, there being lost motion between said lugs and said lever to permit said return movement of pawl carrier.

5. In a loom having a frame, a reciprocating lay and a warp let-oif mechanism, said let-off mechanism including gearing operated by a single ratchet wheel for controlling the advance of a warp sheet, an oscillating pawl carrier for rotating said ratchet wheel, an actuating member reciprocating with the lay, said member being provided with a pair of projecting lugs, a lever fulcrumed to the loom frame and connected to said pawl carrier, one of said lugs being arranged to engage the lever above its fulcrum and the other being arranged to engage the lever below its fulcrum, whereby one of said lugs will engage the lever on movement of the lay in one direction to impart operating movement to the pawl carrier and the other of said lugs will engage said lever to impart an operating movement to the pawl carrier during movement of the lay in the opposite direction, and means for returning the pawl carrier to its initial position between operating movements.

CARL D. BROWN.

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