US2729446A - Tension control means in fabric treating apparatus - Google Patents

Description

Jan. 3, 1956 F. B. MORRILL ET AL 2,729,446

TENSION CONTROL MEANS IN FABRIC TREATING APPARATUS Filed Aug. 29, 1952 2 Sheets-Sheet 1 L,K :I I: :l

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22a. 3 2 2 2a 22d 22 a 2 25 /i' J7 -2 /7 2761 L as g 4 $0 10 l L E Z/ H 2e INVENTOR5 FRANK B. MOPRHJ.

BY EDGAR RUST, JR

HTT'ORNE S Jan. 3, 1956 F. B. MORRILL ETAL 2,729,446

TENSION CONTROL MEANS IN FABRIC TREATING APPARATUS Filed Aug. 29, 1952 2 Sheets-Sheet 2 .'1 TE F 4 k j INVENTORS FRANK 5. MOREILL BY EDGAR C. RUST, JR

TENSION CONTROL MEANS 1N FABRIC TREATING APPARATUS Application'August 29, 1952,Serial No. 307,076 7 Claims. (Cl. 271-23) This invention relates to transporting materials under conditions which tend to change their length, as in processing the materials. More particularly, the invention relates to an improved apparatus for transporting such materials lengthwise while maintaining the material tension substantially constant.

The invention will be described, by way of example, in connection with the processing of fabrics, since the transporting of fabrics in process has heretofore entailed considerable difhculty due to shrinking or stretching of the fabric by the processing fluid. It will be understood, however, that the invention is not confined to the transporting of fabrics.

In the commercial processing of fabrics, they are usually subjected to a number of treatments, such as washing, dyeing, bleaching, drying,'and the like. To meet the demands of modern production techniques, it is desirable to move a web or rope of the fabric continuously at high speed through a container where it is subjected to the treating fluid, which may be in liquid or gaseous form. Accordingly, it has been proposed to move the fabric web or rope through the fluid container by way of a series of upper and lower rolls which transport the fabric to nip rolls at the outlet end of the container. However, the handling of fabrics in this matter has presented a serious problem because the changes in length of the fabric, due to shrinking or stretching by the fluid action, tend to cause wide variations in the tension of the fabric moving over the rolls, and the tension may become sufficient to damage the fabric. As the fabric progresses through the fluid container, there is generally considerable variation in the rate (and sometimes even in the direction) of change in its length due to the fluid, and the problem is further aggravated by the fact that different fabrics will react differently to the fluid, in regard to the amount and rate of shrinking or stretching.

It has been attempted heretofore, in various ways, to prevent the tension from becoming greatenough to harm the fabric as it is moved through the fluid. For example, the upper or lower rolls, or both, have been driven at about the same peripheral speed as the nip rolls, or the lower rolls have been driven at a substantially greater peripheral speed than the nip rolls. Also, eiforts have been made to compensate for excessive tension by using movable rolls which shift from one location to another upon change in tension. The results of these attempts have left much to be desired, largely because they fail to meet one or more of the requirements that (l) the systern should be capable of handling different types of fabrics, from the delicate ones to the strong ones; (2) compensation should be provided for both general and local changes in length or tension and for diiferent rates of local change, to prevent excessive tension at any point; (3) the fabric should be movedsmoothly and evenly through the fluid and at high speed, if desired; and (4) the system should be free vices. v p

The present invention, therefore, has for its principal of complicated de- 2,729,446 Patented Jan. 3, 1956 object the provision of an improved apparatus for transporting fabrics lengthwise and which fulfills these re quirements more completely than has been possible heretofore.

Another object is to provide an improved apparatus of the character described, in which the fabric tension is maintained substantially uniform throughout all parts of the fabric being transported, regardless of variations in the amount or rate of stretching or shrinking at diiferent parts of the fabric.

A further object is to provide an improved apparatus of the character described which is of simple construction and readily adjustable to vary the operating tension on the fabric, such tension otherwise being maintained substantially constant.

In an apparatus made according to the present invention, a conical drum or conveyor roll is mounted on a rotatable shaft spaced from a second shaft, which may be any member, preferably an idler roller, coacting with the drum to form a loop-like path for the material to be treated. The drum and the idler roller support the material and define its path extending partly around the idler roller and partly around the drum. The drum shaft is driven at constant speed from an electric motor or other suitable driving means, to draw the material along its path and in this way move it through the treating fluid. A movable element is positioned to engage the material in its path between the drum and the idler roller, and is movable generally parallel to the drum axis. A biasing device, operatively connected to this movable element, urges it toward the enlarged end of the conical drum and in this way biases the material laterally toward the enlarged end of the drum. By reason of the conical shape of the conveyor roll or drum, its peripheral surface speed will vary gradually from a maximum at its enlarged end to a minimum at its reduced end, with the drum shaft rotating at constant angular speed. Thus, the linear speed at which the fabric passes over the drum will depend upon its position axially of the drum, as deter mined by the lateral biasing device, and can vary between these maximum and minimum limits.

The materiai to be treated is delivered to the conical drum and roller system at a linear speed intermediate the maximum and minimum surface speeds of the conical drum, preferably by means of a feed control device. This feed control device may comprise a pair of nip rolls between which the material passes toward the conical drum, and one of these nip rolls is positively driven at the same angular speed as the conical drum and has a diameter equal to that of the drum approximately mid-way between its ends. With this arrangement, assuming that the material neither shrinks nor stretches during its transport, it will tend to center itself on the conical drum where the peripheral speed of the drum is equal to the linear speed at which the material is delivered by the nip rolls.

If the material shrinks as it travels between the conical drum' and the idler roller, the increased tension moves it laterally toward the reduced end of the conical drum where the surface speed of the drum is less, thereby c'ounteracting the increase in tension. However, this lateral movement of the material on the drum is yieldingly opposed by the biasing device through the movable element engaging the material. Thus, the lateral movement of the material toward the reduced end of the drum is arrested when the tension in the material is balanced by the force of the biasing device urging the material toward the enlarged end of the drum. Conversely, if the material stretches during its travel, the biasing de vice moves it toward the enlarged end of the conical drum where the surface speed of the drum is greater, until the force of the biasing device is balanced by the tension in the material. In this way, the apparatus compensates immediately and automatically for either shrinking or stretching of the material during its travel through the treating fluid, and the material is maintained at all times under a substantially constant tension, the magnitude of which can be readily adjusted by adjusting the lateral force appplied to the material by the biasing device.

In its preferred construction, the apparatus has a series of conical drums mounted on a common rotatable shaft; and the material passes in a spiral or loops via one drum, the idler roller, the second drum, the idler roller, the third drum, etc., so that the treating chamber will always contain a considerable length of the material during its travel through the chamber. Each of the conical drums has a biasing device associated with it, to urge the material in the corresponding loop toward the enlarged end of the drum. Thus, local changes in the material length, due to either stretching or shrinking, are automatically compensated regardless of where they occur in the treating chamber.

A better understanding of the invention may be had from the following description taken in conjunction with the accompanying drawing, in which:

Figure l is a front elevational view of a preferred form of the new apparatus, with the front wall of the fabrictreating chamber removed to show the interior, and

Figure 2 is a sectional view taken along the line 22 of Figure 1.

Referring to the drawing, the apparatus there shown is for treating a rope fabric F in a container The container forms a treating chamber partly filled with water or any other appropriate treating agent (not shown). At the bottom of the container 10, and below the level of the treating agent, is an idler roller or shaft 11 mounted for rotation in bearings 12a and 12b. At the upper region of the container lid is a shaft 13 journaled in bearings 14a and 14b. Positioned on an extension of the shaft 13 is a pulley 15 which is driven at constant speed by an electric motor 16 through the motor pulley 16a and belt 17. A second belt 18 connects pulley 15 to a pulley 19 on a shaft 20 rotatably mounted in suitable bearings (not shown). The shaft 2% drives a nip roll 21 adjacent a second nip roll 21a.

The shaft 13 supports and rotates a plurality of tapered or conical drums indicated generally at 22. in the embodiment here illustrated, the conical drums 22 comprise identical cone-shaped rollers 22a, 22b, 22c 22d and 22e positioned in contiguous relation on shaft 13 with their tapered ends extending toward the pulley 15. Discs 23 are provided at the ends of the respective drums. The peripheral or surface speed of each conical drum 22 at a point about midway between its ends is equal to that of the nip roll 21. This may be effected by making the driven angular speeds of shafts 13 and 20 equal and making the diameter of nip roll 21 equal to that of each drum 22 at a point midway between its ends.

Approximately midway between the idler roller 11 and the shaft 13 is an inverted channel member 25 for supporting a plurality of biasing devices indicated gen erally at 26. Each tapered drum 22 has a biasing device 26 associated with it. Since the respective biasing devices 26 are identical, a description of one will sufiice for all. In the embodiment here illustrated, I have shown the biasing means as comprising a crankshaped lever 27 having a lower horizontal arm 27a extending through the sides of the channel member 25, and an upper horizontal arm 27b adapted to engage the fabric F. The lower arm 27a is rotatable in the channel member 25 and carries a depending weight 28 which extends at about right angles to the upper arm 27b, as shown in Fig. 1. Thus, the upper arm 27b constitutes an element which is pressed laterally against the fabric F by the weight 28. Each conical roller or drum 22 tapers in a direction opposite to the direction in which the corresponding lever arm 27b is urged by its weight 28.

The fabric F, in the form of a rope or narrow web, passes between the nip rolls 21, 21a, then downwardly into the treating fluid in container 10 and under and partly around the idler roller 11, then upwardly against the lever arm 27b of the first biasing device 26, and then over and partly around the first cone-shaped roller 22a. From roller 2201, the fabric passes downwardly into the liquid, then under and partly around idler roller 11, and so successively to the rollers 22b, 22c, 22d and 222 via the corresponding biasing means 26 associated with them, and the idler roller 11. From the last cone roller 22c, the fabric F passes under and partly around a dance roll 30, which may be arranged in a conventional manner, and thence upwardly from the container and between a second pair of nip rolls 31, 31a similar to the first pair 21, 21a which serves to control the feeding of the fabric to the container. The dance roll 3t controls a motor 32 through a suitable connection (not shown) so that the discharge roll 31 is driven from motor 32 at a speed determined by the position of the dance roll 30, whereby the fabric is drawn from the apparatus under substantially constant tension, as will be apparent to those skilled in the art.

It will be understood that the fabric F is supported in the container in a series of loops substantially in spiral form, with the lower portions of the loops immersed in the treating fluid. The fabric is fed to the first of these loops at a linear speed equal to the surface speed at the central part of each cone 22, by the feed control device comprising the nip rolls 21, 21a and their driving means 15, 18 and 19".

The gravitational pull on each weight 28 exerts a torque on its lever 27, so that the corresponding arm 27b yieldingly urges the adjacent fabric F to the right as seen in Fig. 1, that is, toward the enlarged end of the respective cone 22. This lateral force exerted by each lever arm 27b is opposed by the tension in the adjacent section of fabric F. If the fabric were to pass through the treating chamber with no shrinking or stretching whatever, this tension would be just sufiicient to hold the fabric on the central portions of the drums 22 (against the action of the biasing devices 26) where the surface speed of the drums equals the linear rate at which the fabric is delivered by the feed rolls 21, 21a. When the fabric shrinks during its passage through the treating bath, the increased tension causes the fabric in the region of shrinking to bear against the adjacent lever arm 2711 with increased force and ride toward the small or tapered end of the corresponding cone 22. As a result, the fabric will now engage this cone at a region of reduced surface speed (that is, at a region where the cone has a surface speed less than the speed at which the fabric is delivered by the feed rolls Z121a), thereby counteracting the increase in tension. This shifting of the fabric toward the reduced end of the cone 22 continues until an equilibrium position is reached at which the tension in the fabric balances the force of the biasing device 26. Conversely, when the fabric F stretches, the biasing device 26 in the region of stretching urges the fabric F toward the larger end of the corresponding cone 22 so that the fabric engages the cone at a region of increased surface speed, thereby counteracting the decrease in tension. This shifting of the fabric toward the enlarged end of the cone 22 continues until an equilibrium position is reached in which the fabric tension balances the lateral thrust of the biasing device 26 against the fabric. It will be understood that shifting of a fabric loop in either direction on its corresponding cone 22, as previously described, will tend to cause a shifting of the preceding loops in the same direction on their respective cones, due to the resulting change in the rate at which the fabric is fed to these prc ceding loops. For example, assume that the fabric in the loop between the cones 22a and 22b should shrink, so as to shift the fabric toward the reduced end of cone 22b, thereby decreasing the linear speed at which it is drawn around the cone 22b. The fabric will then be fed at a slower speed to the preceding loop between cones 22b and 22c, which will tend to increase the tension in the latter loop and thus shift the fabric on cone 22c toward its reduced end. The resulting decrease in the speed at which cone 22c feeds the fabric to the preceding loop between cones 22c and 22d will cause a similar action on the latter loop, etc. The fabric being treated may simultaneously shrink in one loop and stretch in another loop, in which case the above-described compensatory actions of the corresponding biasing devices 26 and cones 22 will likewise occur simultaneously as required by local conditions. In this manner, substantially constant tension is maintained on the fabric at all times throughout its length and under all conditions during the treating operation.

It will be understood that the force of each biasing device 26 increases as the adjacent fabric moves from the enlarged end toward the central portion of the corresponding cone 22, since the effective length of the moment arm of the corresponding weight 28 increases as the weight is raised. Then, as the fabric moves beyond this central portion and toward the reduced end of the cone, the force of the biasing device decreases due to the weight 26 moving beyond its horizontal position. By changing the angle of the weight 26 relative to the arm 27, the biasing force can be made to undergo other desired variations as the fabric moves lengthwise of the cone, to suit individual requirements. However, it is not necessary that the biasing devices function to exert a varying force. That is, the

apparatus will operate very satisfactorily if the biasing devices 26 are arranged to exert a constant thrust on the fabric regardless of its position on the cones 22. Also, the biasing devices may take other forms, such as springs, magnets, air cylinders, etc.

In order to limit the extent to which the position of the fabric on one cone may affect the position of the fabric on the next cone, we provide guides 34 in the form of pins mounted on a support 35 near the idler roller 11. One guide pin 34 is provided for each fabric strand passing to the idler roll 11 and is positioned to be engaged by this strand so as to limit its movement in the direction from the smaller to the larger ends of the cones (to the right, as viewed in Fig. 1). Without these guides, if the strand moving onto the first cone 22a, for example, were to move to the right of its position shown in Fig. 1, the strand leaving cone 22a and looping under shaft 11 would also move to the right. This would unduly upset the equilibrium of the biasing device 26 associated with the next cone 22b, by causing too great a change in the angle of approach of the fabric to this biasing device. Thus, the guides or stops 34 enable each conveyor cone and its associated biasing device to establish their own equilibrium substantially independently of the others.

The member 11, which defines the path of the fabric in the lower parts of the loops, should have a smooth surface to allow slippage of the fabric relative thereto, as the fabric may pass around this member at different speeds in different loops. If the surface of this member is sufiiciently smooth so that its frictional resistance can be overcome by the pull on the fabric from the cones 22, without causing slippage of the fabric on the cones, the member 11 need not be rotatable. If desired, the member 11 may comprise separate rollers, one for each fabric loop.

I claim:

1. Apparatus for transporting a length of material under substantially constant tension through a treating fluid, which comprises a rotatable shaft, a member spaced from the shaft and held against bodily movement toward and away from the shaft, a conical conveyor drum on the shaft adapted to support the material in a loop extending partly around the drum and said member,

means for feeding material into said loop, means for driving the drum shaft to advance the material in the loop and withdraw material from the loop, a movable element positioned to engage the material in said loop and movable generally parallel to the rotation axis of the conical drum, and a biasing device operatively connected to said element and urging it toward the enlarged end of said drum, whereby the material is biased toward said enlarged end.

2. Apparatus according to claim 1, in which said feeding means include a feed device located in advance of the conical drum and operable to feed the material into said loop, and means for operating said feed device to feed the material at a linear speed intermediate the surface speeds of the conical drum at its ends.

3. Apparatus for conveying a length of material under substantially constant tension from a supply point to a delivery point, which comprises a rotatable shaft, means for driving said shaft, a plurality of conical drums mounted on said shaft, a member spaced from the shaft and held against bodily movement toward and away from the shaft, said member and drums forming a path of travel for the material passing partly around each of said drums and said member in loops between said points, means for feeding material into the first of said loops, the drums being operable during the driving of said shaft to advance the material in the loops and withdraw it from said loops, and biasing means for each of said drums positioned adjacent the path of travel and yieldingly urging said material toward the enlarged ends of the respective conical drums.

4. Apparatus according to claim 3, in which each biasing means comprises a lever having two arms, one of which is positioned to engage the material, and a weight secured to the other arm for urging the first arm against the material.

5. Apparatus according to claim 3, in which said feeding means include a feed device located in advance of the conical drums and operable to feed the material into said loops, and means for operating said device to feed the material at a linear speed intermediate the surface speeds of the conical drums at their ends.

6. Apparatus according to claim 3, comprising also a guide adjacent each loop of said path and engageable by the part of the loop moving toward said member, each guide being positioned to limit the movement of said loop part in the direction from the reduced to the enlarged ends of the drums.

7. Apparatus for transporting a length of material under substantially constant tension through a treating fluid, which comprises a rotatable shaft, 21 member spaced from the shaft and held against bodily movement toward and away from the shaft, a conical conveyor drum on the shaft adapted to support the material in a loop extending partly around the drum and said member, means for simultaneously feeding material into and withdrawing it from said loop, a movable element positioned to engage the material in said loop and movable generally parallel to the rotation axis of the conical drum, and a biasing device operatively connected to said element and urging it toward the enlarged end of said drum, whereby the material is biased toward said enlarged end.

References Cited in the file of this patent UNITED STATES PATENTS 939,350 Thompson Nov. 9, 1909 1,100,801 Wendell June 23, 1914 1,114,478 Ibarra Oct. 20, 1914 1,169,096 Thornton Jan. 18, 1916 1,385,403 Sentou et a1. July 26, 1921 2,120,735 Debrie June 14, 1938

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