US2893441A - Constant rate let-offs - Google Patents

Description

July 7,1959

T. J. OLIVER CONSTANT RATE LET-OFFS Filed Jan. 10, 1957 m i 3 0; I "0 i k I 3? f w l Tomcw J 02127423 United States Patent 2,893,441 Patented July 7,. 1959 CONSTANT RATE LET-OFFS Thomas J. Oliver, Wetumpka, Ala., assignor to H. F. Livermore Corporation, Boston, Mass., a corporation of Delaware Application January 10, 1957, Serial No. 633,477

6 Claims. (Cl. 139-108) This invention relates in general to let-ofis for looms, and in particular to let-offs of the well-known Roper type in which a mechanical escapement allows the warp beam to turn and let the warps advance in direct accord with the tension imparted to the warps by the pull of the take-up motion which draws forward the cloth as it is woven.

' In the standard Roper let-off motion as applied to Draper looms, the pallet lever and the let-off ratchet Wheel are mounted by their hubs directly on the pinion shaft which carries at its inner end the let-off pinion that engages with the gear on the warp beam head to control the unwinding rotation of the Warp beam. In operation, the pallet lever is rocker back and forth continuously in time with the beat of the lay, being linked to an arm on the parallel foot on the lay rocker shaft. The let-01f ratchet wheel moves for varying distances, as determined by the varying Warp tension, in the direction of rotation of the pinion shaft but at twice the shafts speed of rotation, at nearly every beat of the lay. Even though these two parts are mounted free on the pinion shaft which so far as they are concerned merely serves as a stud or axle for supporting them rotatably, and though the co-engaging bearing surfaces are presumably kept lubricated, they still urge on or hold back on the pinion shaft, with the result that the pinion shaft is allowed to turn unevenly. The resulting thick and thin places in the woven fabric occasioned by variation in pick count (weft density) thus caused by the changing rate of warp advance form serious and irreparable defects in the quality of the finished fabric.

Also, this constant relative motion of the pallet lever and let-off ratchet wheel against the pinion shaft increases the rate of wear of these parts unnecessarily.

Further, the entire weight of the let-off mechanism is borne by the pinion shaft with the major portion of it outside the loom frame, causing a tendency of the pinion shaft to tilt and bind within its single bearing provided in the let-off stand near the inward end of the pinion shaft.

Additionally, lint and fly have easy access to the hearing surfaces, being caught and held by the lubricant, increasing the friction drag on the pinion shaft to affect the Warp feed adversely.

The present invention has as its leading aim the attainment of a more nearly constant rate of advance of the warps under the pull of the take-up motion. Further objects of the invention are to eliminate the unnecessary wear of the pallet lever and let-01f ratchet wheel and pinion shaft created by letting the lever and wheel bear on the pinion shaft; and additionally to provide greater support for the pinion shaft and better shielding of the bearing surfaces of these parts from ingress of lint and fly to the bearing surfaces.

It is also an aim to provide these improvements in a form which can be applied to existing let-off motions with a minimum of trouble and expense, and with retention and use of all the original parts thereof.

Other objects of the invention, and the manner of their attainment, are as made plain hereinafter.

An illustrative embodiment of the invention is shown in the accompanying drawings, in which Fig. 1 is a rear elevation of the improved let-off, mainly in vertical section.

Fig. 2 shows the improved bearing and supporting element in side elevation.

The relevant parts of a Roper type let-olf, modified in accordance with the invention, are shown in Fig. 1, and comprise a let-01f pinion 1 engaging with the beam gear 3 forming a part of the warp beam head (not shown), the pinion being fixed by screw 5 on the inward end of pinion shaft 7 extending through hub 9 formed as an integral part of let-off stand 11, which is bolted to the loom side. Hitherto, the interior of hub 9 formed the bearing surface for pinion shaft 7, with the pallet lever 13 and hub 15 of the let-off ratchet wheel 17 mounted rotatably directly on pinion shaft 7 by means of their respective hubs 19 and 21.

In accordance with the invention, however, the pinion shaft 7 is kept entirely out of contact with the pallet lever 13 and the ratchet wheels hub 15 and all other parts thereof, by providing a greatly extended hearing or sleeve 23 which is press-fitted into the original bearing within hub 9 after boring out the passage through the latter to accept it. The interior diameter of sleeve 23 throughout its length is made appropriate to receive and serve as the bearing for pinion shaft 7. This sleeve 23 preferably extends throughout the full length of hub 9, beyond which it has a cylindrical portion 25 of increased outside diameter abutting against hub 9, upon which portion 25 is mounted the hub 19 of pallet lever 13, such hub being bored out and finished to rotate freely on this enlarged portion 25. Next the hub 15 with its integral eccentric 27 which drives the let-off internal gear pinion (not shown) working Within internal gear 29 as heretofore, is bored out and finished to rotate freely on the reduced outside diameter of the outward end portion 31 of sleeve 23, and mounted thereon. The ratchet wheel 17 is attached in usual manner to the inward face of its hub 15 by cap screws 33. As before, internal gear 29 and pinion shaft arm 35 with its pawls 37 are mounted directly on pinion shaft 7, the pinion shaft arm 35 being secured by set screw 39. All the usual additional parts of the standard Roper let-01f such as the pinion crosshead, friction clamp and dog, controlling lever, pinion shaft handle, and the rest, are present in their usual 10- cations and utilized in the usual manner, though omitted from the drawing for clarity.

The novel sleeve 23 which thus provides internal and external bearing surfaces for the stated parts is provided with oil holes 41 at locations aimed to line up with the original oil holes 43 in hub 9. To provide for variations in the location of the original oil holes 43, the sleeve 23 is turned down to form shallow peripheral grooves 45 Wide enough to receive oil introduced through the original passages 43 and conduct it to the oil holes 41 and thence to the interior bearing surface of sleeve 23 and to pinion shaft 7.

The usual spacing collar 47 is applied to pinion shaft 7 to bear against the inward end of hub 9 for use in positioning pinion gear 1 properly in mesh with beam gear 3.

Although the present embodiment is designed to change over existing let-off motions without replacement of the original parts, it will be understood that where new motions are to be built the invention principle will be applied by omitting the sleeve 23 and extending the hub 9 with the formation of the bearing surfaces for the pellet lever 13 and hub 21 of the ratchet wheel directly thereon in the same locations as the bearing surfaces 25 and 31 of the sleeve 23.

While I have illustrated and described certain forms the scope of the invention.

in which the invention may be embodied, I am aware that many modifications may be made in the invention by any person skilled in the art, without departing from Therefore, I do not wish to be limited to the particular formsshown, or to the details of construction thereof, but what I do claim is:

1. A warp let-off motion for looms having in combination apinion gear, a pinion shaft, a let-off stand having a hub supporting the pinion shaft, a pallet lever, a ratchet wheel, and a sleeve fixed Within the let-ofi? stand hub and forming the bearing surface for the pinion shaft, pallet lever, and ratchet wheel.

.2. A warp let-off motion for looms having in combination a let-ofi stand having a hub, a pinion shaft extending through the hub, a sleeve fixed within and extending from the hub :and surrounding the pinion shaft, a pallet lleverv .rotatably mounted on the sleeve, and a ratchet Wheel also rotatably mounted on the sleeve.

3. vA warp let-ofi motion for looms having in combination a let-01f stand having a hub, a pinion shaft, a pinion gear thereon, a pallet lever, a ratchet wheel, and ,a sleeve .fixed Within the hub forming the bearing surfaces for the pinion shaft, the pallet lever, and the ratchet wheel.

'4. A warp let-off motion for looms having in combination a leteofi stand, a pinion shaft, a pallet lever, a ratchet wheel, and means in fixed connection with the stand forming the bearing surfaces for the pinion shaft, the pallet lever, and the ratchet wheel.

5. A warp let-off motion for looms having in combination a let-off stand, a pinion shaft, a pallet lever, a ratchet wheel, and means in fixed connection with the stand having internal bearing surfaces rotatably supporting the pinion shaft and external bearing surfaces rotatably supporting the pallet lever and the ratchet wheel.

6. A warp let-0E motion for looms having in combination a let-off stand having a hub, a pinion shaft extending through such hub, a sleeve fixed in the hub having an internal bearing surface rotatably supporting the pinion shaft, and having a portion of increased diameter abutting the hub and forming an external bearing surface, a pallet lever rotatably mounted on the latter hearing surface, and a ratchet wheel, the sleeve having a portion of reduced diameter located outwardly beyond the increased diameter portion and forming an external bearing rotatably supporting the ratchet wheel.

References Cited in the file of this patent UNITED STATES PATENTS 647,815 Draper et al. Apr. 17, 1900 1,528,579 Stafford Mar. 3, 1925 2,609,006 Lord Sept. 2, 1952

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