US2957498A - Stop motion for tight and loose warps - Google Patents

Description

R. S. MARTIN STOP MOTION FOR TIGHT AND LOOSE WARPS Oct. 25, 1960 2 Sheets-Sheet 1 Filed Dec. 9, 1958 INVENTOR: AYMOND S. MARTIN By ofilm,

ATTORNEYS Oct. 25, 1960 R. s. MARTIN 2,957,498

STOP MOTION FOR TIGHT AND LOOSE WARPS Filed Dec 9, 1958 2 Sheets-Sheet 2 INVENTOR. RAYMQND 5. MARTIN ATTORNEYS United States Patent 2,957,498 STOP MOTION FOR TIGHT AND LOOSE WARPS Raymond S. Martin, Fieldale, Va., assignor to Fieldcrest Mills, Inc., Spray, N.C., a corporation of Delaware Filed Dec. 9, 1958, Ser. No. 779,162 1 Claim. (Cl. 139358) This invention relates to warp stop motions for pilefabric or terry looms and, more especially, to an ill]!- proved apparatus for detecting abnormally slackened and/ or parted strands in the socalled loose warp or terry warp to effect operation of the stop motion and wherein operation of the stop motion is not affected by predetermined slackness intentionally induced in the terry warp.

As is well-known, the pile warp in terry and other pile-fabric looms is intermittently advanced relative to the ground Warp preceding each fast pick woven in at the fell of the cloth. Thus, the pile warp becomes slackened or loose relative to the ground warp and is taken up during each fast pick to form terry or pile loops. In order to actuate the usual plain loom stop motion, a drop wire rests upon each ground warp strand and when one of the ground warp strands breaks or becomes excessively slack, the respective drop wire falls into engagement with a detecting bar which actuates the loom stop motion.

Heretofore, drop wires have been used in a similar manner for detecting the presence of broken or excessively slackened terry warp strands. However, apparatus had to operate in conjunction with the terry warp let-off or variable beat-up mechanism of the loom so as to support the terry warp drop wires independently of the terry warp strands during each loose pick and to thereby prevent false loom stoppage. Apparatus of this type is disclosed in US. Patent No. 2,065,731, for example. Such supporting apparatuses necessarily comprise considerable parts which require space on the loom which is already overloaded with parts, and such apparatuses must be precise in their operation and are, therefore, expensive to manufacture, install and maintain? In order to overcome the above and other defects, it is an object of this invention to provide a novel method and apparatus for detecting broken terry warp ends or abnormally slack terry warp strands for actuating the loom stop motion in which drop wires of relatively lightweight construction are supported solely by the terry warp strands and are maintained out of actuating engagement with the detecting bar while they are supported only by the latter strands even though predetermined slack is induced in the strands. However, when the slack in any strand exceeds said predetermined amount or the strand is parted, the respective drop wire is dropped into actuating engagement with the detecting bar.

To this end, I have provided drop wires whose slotted upper portions are of such length that the upper walls of the slots will not drop into actuating engagement with the detecting bar extending through said slots whenever the terry warp is let off to a predetermined extent. Further, I have positioned separator bars in closely spaced relation to and astride the drop wires so as to maintain the drop wires in upright position and to cause the terry warp strands to pass over a rear separator bar, downwardly between the rear and a succeeding separator bar, through the drop wires, and then upwardly over the "forward or succeeding separator bar in its course to the fell of the .cloth whenever slack is induced in the terry ice warp. Thus, the terry strands are subjected to a minimum of stress as they move through the drop wires, since the steeper the slope of the strands, the lesser the stress applied thereto. This also minimizes the resistance to movement of the strands through the drop wires.

Since the upper slotted portion of each terry warp drop wire is relatively long to accommodate its range of vertical movement, it is another object of this invention to provide an improved drop wire whose upper portion, from its strand-contacting point or surface to its upper end, is heavier than its remaining or lower portion, the lower portion being of reduced length to minimize the over-all weight of. the drop wire.

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- Figure 1 is a somewhat schematic side elevation of a terry loom with which a preferred embodiment of my invention is associated.

Figure 2 is a somewhat schematic View similar to the left-hand portion of Figure 1 showing a portion of a conventional stop motion actuating apparatus as used on terry looms prior to my invention;

Figure 3 is a greatly enlarged view of the stop motion detecting apparatus shown in the central portion of Figure 1;

Figures 4 and 5 are isometric views of two types of separator and detector bar support blocks shown in Figure 3.

In Figures 1 and'2, two terry looms or pile-fabric looms are partially illustrated, the loom of Figure 1 being equipped with a preferred embodiment of my improved stop motion actuating mechanism and the loom of Figure 2 showing, by way of comparison, a conventional type of stop motion apparatus such as is disclosed in said US. Patent No. 2,065,731, for example. For purposes of brevity, pertinent parts of the loom shown in Figure 1 will be described and like parts of the loom shown in Figure 2 will bear the same reference characters with the prime notation added, where applicable.

The loom of Figure 1 comprises a frame 10 and a lay L movable in the usual manner by a crank shaft 11. A reed 12 is pivoted, as at 13, to the lay and has wellknown operating connections, not shown, which are eifective periodically to change the angular relation of the reed relative to the lay, the reed 12 and said connections being commonly known as a variable beat-up mechanism. This variable beat-up mechanism usually operates to move the reed 12 to forward position relative to the lay L with certain beat-up strokes of the lay, such as every third pick when producing a three-shot terry fabric. This periodic forward movement of the reed 12 is generally known as a fast pick.

Explaining the operation of the reed 12 further, the reed is so manipulated in a three-shot terry, for instance, as to have a short forward motion on the first and second beats or picks of the cycle in order to leave two shots of filling in different sheds an appreciable distance. behind the fell of the cloth. On the third beat, however, the reed has a full or long forward stroke and beats the three shots of filling together with the terry warp up to the fell of the cloth, thus looping the slack terry warp between the fell and the first of the three shots of filling.

Strands of ground warp G are drawnfrom a ground warp beam 14 which may be associated with any form of let-off, not shown, to produce the usual tension and hold the ground warp relatively tight at all times. A terry or pile warp beam 15 may be mounted on brackets,

"one of which is indicated at 16 in Figure 1. The terry 3 downwardly from terry beam 15 to a terry warp let-E or feed mechanism generally designated at 17. Terry warp let-off 17 comprises front and back rolls 20, 21 which are mounted for rotation on frame and are normally held against each other. Terry warp T passes beneath roll 20, then over roll 21, downwardly to a guide rod 22, and thence forwardly.

A ratchet feeding wheel 23 is secured to rear feed roll '21, and a feed pawl 24 is mounted on a rocking lever 25 which preferably oscillates about the axis of rear feed roll 21. Pawl 24 is controlled by a movable arm 26 which may be connected to a suitable operating means, such as a pattern mechanism, not shown. In Figure 1, arm 26 is shown in lowered position to permit pawl 24 to engage ratchet wheel 23 for rotating feed rolls 20, 21 in a step-by-step manner with oscillation of lever 25. Of course, during the weaving of a heading, in which no terry loops are to be formed, arm 26 is raised by the pattern mechanism so that the terry warp T then remains taut during the weaving operation.

Rocking lever 25 is oscillated by means of a cam 30 mounted on a shaft 31 carried by frame 10. Cam 30 is engaged by a follower 32 mounted on the front end of a lever 33 oscillatably mounted on frame 10, as at 34, and having the lower end of a connecting rod 35 connected to its rear end. Cam 30 is shown in the form of an eccentric and is operatively connected to a gear, indicated diagrammatically at 36, rotating about shaft 31. Gear 36 is engaged by a gear 37 fixed on a driven main shaft 40. Assuming that the loom is set up for weaving a three-shot terry fabric, gear 37 may be two-thirds as large as gear 36 so that connecting rod 35 is given an upward movement every third beat of the loom.

The lower or ground warp G is led upwardly from beam 14 over a guide bar 41 and passes forwardly toward the warp stop motion control generally designated at 42. It will be noted that roll 22 is mounted on adjustable brackets 44 so that roll 22 may be vertically adjusted and whereby the terry warp T extends forwardly and downwardly from roll 22 at an angle relative to the substantially horizontal upper portion of the ground warp G. The ground and terry warps G, T then extend forwardly from the stop motion control 42, through the usual harnesses or heddles 43 and to reed 12 where they are formed into pile or terry fabric generally designated at F. The terry fabric F may be taken up as it is Woven in a well-known manner at the front of the loom.

As is well-known, conventional stop motions or stop motion controls for terry and ground warps include banks of drop wires with the strands each passing through one of the drop wires and, upon parting of any one of the terry or ground warp strands, the corresponding drop wires drop downwardly against detecting bars for actuating the stop motion. However, due to the fact that slack is induced in the terry warp periodically, the terry warp drop wires have had to be supported by means other than the terry warp strands passing therethrough or the detecting bars extending through the terry warp drop wires had to be momentarily rendered ineffective in order that the dropping of the terry warp drop Wires effected by induced slack in the terry warp strands would not cause false stoppage of the loom. A device for supporting the terry warp drop wires during the fast picks; when slack is induced in the terry warp strands, is disclosed in said US. Patent No. 2,065,731 and an illustration of a. similar form of conventional device is shown in Figure 2 for the purpose of comparing a known type of terry warp stop motion with that embodied in the present invention.

Referring to Figure 2, it will be noted that the strands of ground warp G extend through banks of drop wires A and the strands of terry warp T extend through front banks of drop wires B, there being one drop wire for each strand in each instance. The drop wires A, B are all of the same general conventional CQ 'l ction, each having a relatively heavy or solid lower portion 45 and a slotted upper portion 46. A detecting bar 47 extends through the slotted upper portions 46 of the drop wires A, B in each bank and is adapted to be engaged by the upper wall of the corresponding slot in any drop wire which is permitted to drop due to the occurrence of excessive slack in any respective terry or ground warp strand or upon any respective strands becoming broken or otherwise parted. The terry and ground warps extend above separator bars or rods 50 which are disposed adjacent opposite sides of each bank of drop wires A, B to assist in retaining the drop wires in proper position as the terry and ground warp strands T, G are drawn through the drop wires.

Opposite ends of the detecting bars 47 and separator bars 50 are suitably clamped or otherwise supported between series of support blocks only one of the sets of support blocks being shown in Figure 2 indicated at 52. Support blocks 52 are all mounted on a common threaded shaft 53 having nuts 54 on opposite end portions thereof for clamping the blocks 52 therebetween. The rear end of shaft 53 is curved downwardly and fixed in a bracket 55 carried by frame 10'.

As heretofore stated, the conventional terry warp stop motion includes means to support the terry warp drop wires when the terry warp is slack, and such means generally raises the terry warp drop wires slightly above their normal position so that their weight is taken off the terry warp. To this end, a lifter plate 60 is positioned beneath the front pair of banks of drop wires B. Opposite ends of litter plate 60 are fixed to levers 61, only one of which is shown, and these levers are operated by means, such as cam 30, so as to move upwardly and lift the two banks B of terry warp drop wires at the same time that the slack is induced in the terry warp T by the feed mechanism or let-off 17', thus preventing the terry warp drop wires B from falling into engagement with the respective detecting bars 47 even though induced slack is present in the terry warp T. This also avoids placing undue stress on the terry warp T as it is taken up with the succeeding fast pick of the loom. Since an example of suitable apparatus for controlling and imparting movement to levers 61 and lifting plate 60 is disclosed in US. Patent No. 2,065,731, a further description and illustration thereof is deemed unnecessary. Although the conventional type of terry warp stop motion illustrated in Figure 2 operates satisfactorily in some respects, it is apparent that the use of a plate such as plate 60 or a similar mechanism for raising the terry warp drop wires B requires considerable parts which are costly to manufacture and which must be precise in their operation. Further, since the terry warp drop wires B of the conventional terry warp stop motion control are supported during the forming of induced slack in the terry warp T, the parting or excessive slackness of any of the terry warp strands is not detected during such intervals. Also, since cam 30 is driven throughout operation of the loom, the lifting plate 60 continues to operate for periodically raising and lowering the terry warp drop wires B even during intervals in which terry loops are not being formed, such as during the weaving of the usual heading.

Now, there is shown in Figures 1, 3, 4 and 5 an improved terry warp stop motion control for carrying out my improved method which stop motion control obviates the necessity of providing apparatus of any kind for raising the terry warp drop wires while producing predetermined slack in the terry warp T and which also enables detection of broken or abnormally slack terry warp strands at all times during operation of the loom regardless of whether or not the terry warp has induced slack therein and without interfering with the taking up of the slack in the terry warp with fast picks in the forming of terry loops. Referring to Figures 1, 3, 4 and 5, the terry warp stop motion control 42 is also embodied in four banks of drop wires, including two banks of ground warp drop wires C and two banks of terry warp drop wires D.

The ground warp drop wires C and associated detecting bars, separators and supports therefor may be of any desired or conventional construction, such as the corresponding elements shown in Figure 2, the detecting bars for the ground warp drop wires C each being designated at 70 and the separator bars being designated at 71, 72 and 73. The detecting bars 70 are shown as being of a type used for controlling an electrical stop motion. However, it is apparent that the features of my invention apply equally well to any form of warp stop motion which depends for its operation upon the falling of a drop wire. In this instance, the separator bars 71, 72 are mounted in notches or slots 75 provided in support blocks 76, which support blocks are also provided with notches 77 in the upper portions thereof for supporting corresponding ends of the detecting bars 70. As is conventional, blocks 76 are mounted on a threaded shaft 80 having nuts 81 thereon for clamping the bar supporting blocks therebetween.

It will be observed in Figure 1 that each shaft 80, only one of which is shown, extends downwardly at its rear end and'is fixed in a bracket 82 carried by the frame 10. As is usual, the. ground warp strands G pass above separator bars 71, 72, 73 and each passes through an eye or opening 84 in a medial portion of a respective drop wire C. In this instance, each drop wire C has a slot 85 in its upper portion through which the corresponding detecting bar 70 loosely extends and, since the present stop motion control is shown as being of a' type used for controlling an electrical stop motion, opposed side walls of each slot 85 in the upper portion of each conventional drop wire C are provided with projections 86 which are adapted to engage insulatably separated contact elements 87, 88 of the respective contact bar 70 for closing a circuit therebetween whenever any one of the ground warp strands G is parted or becomes abnormally slackened to the extent that the corresponding drop wire C will drop downwardly to where the projections 86 will engage the contact elements 87, 88.

The terry Warp drop wires D are of construction similar to conventional drop wires (see U.S. Patent No. 2,556,332, for example) to the extent that they are made from a relatively thin light metal and each includes a slotted upper portion 90 and a slotted lower portion 91 provided with respective elongated slots 92, 93 therein.

The slot 93 is preferably open at its lower end and the upper wall of slot 93 serves as a seat resting upon a respective terry Warp strand. Detector bar means, comprising detector bars 94 extend through the upper slots 92 in the respective banks of drop wires D and in this instance, the detector bars 94 are each in the form of an electrical contact bar adapted to be engaged by the inclined upper wall 95 of a respective drop wire upon the latter being permitted to drop due to the presence of abnormal or excessive slack in the respective terry warp yarns or due to the breakage or parting of the respective terry warp yarn or strand. Each detector bar 94 is mounted in and insulated from a detector bar holder 96 and each end of each detector bar holder 96 is positioned in a notch 97 provided in a respective detector bar support block 98 mounted on shaft 80.

Since the drop wires -D are of substantially lighter construction than the drop wires C, the contact or detector bars 94 are preferably relatively narrow with respect to the vertical. This also positions the upper edges of the bars 94 substantially below the level of the upper edges of the main contact or detector bars 70. Accordingly, the blocks 98 are preferably reduced in height as best shown in Figures 3 and 5, as compared to the main detector bar supports 76 shown in the left-hand portion of Figure 3 and in Figure 4. The upper ends of the blocks 98 are notched at 97 for receiving therebetween corresponding ends of detecting bars 94 and holders 96.

The lower portions of the detector bar support blocks 98 are also relatively thin horizontally at notches of slots 99, as compared to the conventional blocks 76, in order to support separator bars 100, 101 in relatively closely spaced relationship and to also support separator bar 100 in relatively closely spaced relation with respect to separator bar 73. This provides a relatively narrow space through which the lower portions 91 of terry warp drop wires D loosely extend. This not only assists in maintaining the drop wires D in substantially upright position, but also insures that the portions of terry yarn or terry Warp strands, which are pulled downwardly into the space between adjacent separator bars 73, 100 or 100, 101 by the respective drop wires D, extend at the steepestpossible angle from the points at which they are contacted by the upper walls of the slots 93 to the upper edges of the respective separator bars. Thus, each time that terry warp T is let off or fed, drop wires D move downwardly and partially draw the terry Warp in which slack has been induced downwardly between adjacent separator bars and, as the induced slack is subsequently removed from the terry warp with the succeeding fast pick of the lay L and reed 12, drop wires D otter a minimum of resistance to the movement of the terry warp therethrough and also apply very slight stress to the terry warp strands while they are being taken up with thefast pick. The angle at which the terry warp strands extend between roll 22 (Figure 1) and drop wires D may also be varied somewhat, through trial-and-error, to establish the optimum angle at which the yarn will most readily pass through the terry warp drop wires without being placed under excessive stress by vertical adjustment of the rod or roller 22, it being well-known that the steeper or more acute the angle of the yarn as it enters and leaves opposite sides of each drop wire, the more easily the yarn or terry strand passes through the slot 93 in the lower portion of each terry warp drop wire D.

Now, the important difference between the terry warp drop wires of the present invention and conventional drop wires lies in the fact that the upper wall 95 of slot 92 is disposed on a substantially higher level relative to the upper edge of the corresponding detector bar 94 and relative to the level of the upper edges of the separator bars than is usually the case, in order to insure that, whenever predetermined slack is induced in the terry warp T, with consequent slackening of the terry warp T at the drop wires D, the upper walls of slots 93 in drop wires D remain in contact with and are solely supported by the strands of terry warp.

It follows, therefore, that the drop wires D move downwardly to a considerable extent each time slack is induced in the terry warp T by the feed mechanism 17. In spite of this, the upper walls 95 of the slots 92 in the slotted upper portions of the terry warp drop wires D are maintained above the level of or out of contact with the terry warp detector bars 94. Also, in order that movement of the terry warp strands through the terry warp wires D is not resisted due to constant engagement of drop wires therewith while the terry warp strands are caused to form loops between adjacent separator bars, the additional weight effected by providing the additional length to the upper portions 90 of the terry warp drop Wires D is compensated for by reducing the length of the lower portions 91 of the terry warp drop wires D so that the terry Warp drop wires D are actually top-heavy.

It is thus seen that I have provided a novel method and means for controlling a loom stop motion in which the upper walls or contact means of the slots 92, through which the contact bars or detector bars extend, are maintained out of actuating position or out of contact with the detector bars 94 while the terry motion drop wires D are supported solely upon the respective terry warps during both induced slack and taut conditions of the terry warp and wherein, regardless of whether the slack is induced in the terry warp or the terry warp is under normal tension, upon the presence of abnormal or excessive slack in any one or more of the terry warp yarns or upon the parting or breakage of any one or more of the terry warp yarns, the respective drop wires D drop further to where the upper walls of the slots in the upper portions thereof engage the respective detector bars for actuating the loom stop motion, thus obviating the necessity of providing external means (other than the terry warp yarns) for maintaining the terry warp drop wires out of actuating engagement with the terry warp contact or detector bars during the intervals in which the terry warp is let off or slackened by the let-off or feed mechamsm.

In the drawings and specification there has been set forth a preferred embodiment 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, the scope of the invention being defined in the claim.

I claim:

In a terry loom having a terry warp and a ground warp, an oscillatable reed and means for intermittently letting ofl said terry warp to provide slack therein preceding successive fast picks of the reed whereby said slack is taken up and terry loops are formed of the terry warp with each fast pick, an improved warp stop motion comprising at least two first and second banks of a plurality of drop wires, each of said drop wires in the first bank resting upon and being solely supported by one of the strands of said terry warp, each drop wire in said second bank resting upon one strand of said ground warp, each wire having a slot in its upper portion, a first stationary detecting bar extending through the slots in the wires of said first bank, a second stationary detecting bar extending through the slots in the wires of said second bank, the upper wall of each slot in the wires of said first bank being spaced suiiiciently above the bar to remain out of contact with said bar each time said terry warp is slackened by said letting off means, and the upper Walls of the slots in said second bank of wires being substantially closer to the second bar than are the upper walls of the slots in said first bank relative to said first bar whereby the upper walls of the slots of said first bank will engage said first detecting bar only upon slack in respective strands of terry warp exceeding the amount of slack efiected in the terry warp by the letting off means or upon the respective strand of terry warp being parted, and whereby the upper portions of the walls of the slots of said second bank will engage said second detecting bar upon the occurrence of relatively little slack in respective strands of ground warp as compared to the amount of slack effected in the terry warp by the letting off means.

References Cited in the file of this patent UNITED STATES PATENTS 1,019,026 Cutting et al. Mar. 5, 1912 1,322,671 Davis Nov. 25, 1919 2,065,731 Payne Dec. 29, 1936 2,844,860 Ayars et a1. July 29, 1958 FOREIGN PATENTS 557,294 Germany Aug. 20, 1932

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