Apparatus for drawing filamentary polymeric material

Abstract

 The invention relates to a device for drawing filamentary polymeric material. Known devices have the problem that "string-up" from a source of the material to a take-up means is not simply and efficiently accomplished and there is considerable operator exposure to rollers moving at very high speeds.
In order to overcome these problems the invention provides at least three rollers (A, B, C, D) at least two of which are motorized. One or more of the rollers are movable between a first and second position, whereby in the first position the filamentary material can be passed from the source through the space between certain of the rollers (A, B, C, D) to the winding means, and by moving one or more of the rollers to the second position the filamentary material (8) contacts the surface of the rollers over a surface angle of less than 360° and adheres thereto without slippage and is drawn there through when the rollers (A, B, C, D) are rotated.

Description

[0001] The present invention relates to the manufacture .of synthetic filamentary polymeric structures. In particular, it relates to the stretching of the filamentary polymeric structures without any operator exposure to moving rollers during string-up from source to take-up.

[0002] Stretched filaments of synthetic high polymers have been conventionally produced in good yields for many years in two distinct process stages, which are separated from one another in respect of both space and time. That is to say, spinning is first accomplished, generally at speeds up to about 1000 to 1200 meters per minute, followed by a separate drawing step which is accomplished on a draw-twisting or draw-winding machine. A more recently developed method of obtaining stretched filaments of synthetic high polymers comprehends spinning and stretching continuously, as in the so-called "spin- draw" processes, the latest modifications of which continuously combine spinning, stretching, and winding with interlacing (or intermingling) and/or texturizing. Similarly the so-called "draw-texturizing" processes continuously combine stretching and winding with texturizing (and interlacing). Exemplary of the aforementioned processes are the inventions disclosed in the following patents: U.S. 2,289,860; U.S. 3,452,130; U.S. 4,035,464; U.S. 3,555,808 and U.S. 3,448,186.

[0003] Notwithstanding the efficacy of these and similar processes involving the drawing of filamentary polymeric material, they are all found wanting in one important aspect; viz., string-up from source to take-up is not simply and efficiently accomplished, especially in coupled processes, and there is considerable operator exposure to rollers moving a very high speeds. The present invention, which obviates these difficulties and inadequacies of the prior art, is nowhere disclosed or remotely suggested by any of the processes or devices of the prior art.

[0004] According to the present invention there is provided a device for drawing filamentary polymeric material, characterised by a roller assembly comprising at least three rollers, at least two of which are motorized, the rollers being spaced from each other in a first position providiing for passage of.filamentary polymeric material in a straight line from a source of supply thereof through the space between the rollers and thence to a means for winding the filamentary polymeric material into a package on a support; and means for moving at least one of the rollers to a second position providing for contact of the filamentary polymeric material with the surface of each motorized roller over a surface angle of less than 360°; whereby the filamentary polymeric material adheres to the surfaces of the motorized rollers without slippage and is drawn between the upstream and downstream motorized rollers when these rollers are caused to move into position, to effect string-up from source to take-up simply and without any operator exposure to moving rollers.

[0005] As a result, the filamentary polymeric material adheres to the surfaces of the motorized rollers without slippage and is drawn between the upstream and downstream motorized rollers when these rollers are caused to move. String-up from source to take-up has been effected simply and efficiently and without.any operator exposure to moving rollers, and the device has been advanced into the operation mode, free of any complexity.

[0006] An especially desirable and preferred embodiment of the present invention provides a device for drawing filamentary polymeric material comprising first and second ruller turrets spaced from each other, each roller turret comprising two motorized rollers which are spaced from each other and communicate with each other by means of a cross-member joining the shafts thereof, the motorized rollers of the first turret being designed to operate at a surface velocity of V₁ and V₂ respectively, and the motorized rollers of the second turret being designed to operate at a surface velocity or V₃ and V₄ respectively, wherein V₁≤V₂, V₃≤V₄, and V₂<V₃, the roller turrets having a first position providing for passage of filamentary polymeric material from a source of supply thereof through the space between the motorized rollers of the first turret, thence through the space between the motorized rollers of the second turret, and thence to a means for winding the filamentary polymeric material into a package on a support; and means for rotating each roller turret in either a clockwise or counterclockwise direction through an angle less than 360° to a second position providing for contact of the filamentary polymeric material with the surface of each motorized roller over a surface angle of less than 360°.

[0007] For the very best results, the surfaces of the motorized rollers should have a surface roughness height index value of 32 RMS or less.

[0008] When the aforementioned preferred embodiment of the present invention is employed, filamentary polymeric material is wound into a package at speeds up to and including 6,000 meters per minute.

[0009] Moreover, it has been found to be especially advantageous in the employment of the aforementioned preferred embodiment .of the present invention if such embodiment additionally comprises (a) sensing means positioned downstream from the second roller turret for the detection of a break in the moving threadline of the filamentary polymeric material coupled with (b) interrupting means for stopping the rotation of the motorized rollers and returning the roller turrets to the first defined position thereof.

[0010] It is very convenient in the utilization of the aforementioned preferred embodiment of the present invention if the roller turrets thereof are rotated from the first to the second defined position thereof through an angle of about 250°; and most conveniently if the first roller turret is rotated in a counterclockwise direction, and the second roller turret is rotated in a clockwise direction. Under such conditions, optimum results are conveniently achieved when the surface velocities of the motorized rollers are defined by the following relationships: V₁=V₂; V₃ = V₄; and V₂<V₃.

[0011] The present invention will now be described further, by way of example only, with reference to the accompanying drawings, in which:-

Fig. 1 is a perspective view, schematically representing an especially preferred embodiment of the present invention in a first defined position thereof, as hereinafter explained in detail;

Fig. 2 is a perspective view schematically representing the same embodiment in a second defined position thereof, as hereinafter explained in detail; and

Fig. 3 is a side view, schematically representing the embodiment of Figs. 1 and 2, which is provided with additional cooperative components.

[0012] Referring now to the Drawings, a particularly preferred embodiment of the present invention (1) is shown in Figso 1 and 2. The embodiment comprises first roller turret (1a) and second roller turret (1b). Roller turret (1a) has two motorized rollers (A) and (B), which are spaced from each other and communicate with each other by means of cross-member (2), joining shafts (4) of rollers (A) and (B). Roller turret (1b) has two motorized rollers (C) and (D), which are spaced from each other and communicates with each other by means of cross member (2¹), joining shafts (4) of rollers (C) and (D). Motorized roller (A) is designed to operate at a surface velocity of V₁; motorized roller (B), of V₂; motorized roller (C), of V₃; and motorized roller (D), of V₄. Surface velocity V₁ is less than or equal to V₂; surface velocity V₃ is less than or equal to V₄; and V₂ is less than V₃.

[0013] Fig. 1 depicts roller turrets (1a) and (1b) being disposed in a first position providing for passage of filamentary polymeric material (8) from a source of supply thereof (not shown) through the space between motorized rollers (A) and (B), thence through the space between motorized rollers (C) and (D), and thence to a means for winding the filamentary polymeric material into a package on a support (not shown).

[0014] By means of pivots (3) and (3¹), roller turrets (1a) and (1b) are caused to rotate to a second position as shown in Fig. 2. The rotation of the individual roller turrets may be either in a clockwise or counterclockwise direction. In Fig. 2, roller turret (1a) is shown as having been rotated in a counterclockwise direction, and roller turret (1b) is shown as having been rotated in a clockwise direction, presenting a configuration which is very conveniently and advantageously employed. The rotation of each roller turret should be through an angle of less than 360°. Fig. 2 shows the rotation of roller turret (1a) through an angle of about 250° and the rotation of roller turret (1b) through an angle of about 250°, presenting a configuration which has been found to be especially useful. As a result of rotation of the individual roller turrets to the second position thereof, filamentary polymeric-material (8) is caused tc contact the surface of the motorized rollers over a surface angle of less than 360°, as seen in Fig. 2. When rollers (A), (B), (C), and (D) caused to rotate at surface velocities V₁, V₂, V₃, and V₄₁ respectively, as hereinbefore set forth, filamentary polymeric material (8) adheres to the surfaces of the motorized rollers without slippage and is drawn between the first and second roller turrets. Especially good results are achieved when the surfaces of the motorized rollers have a surface roughness height index value of 32 RMS or less, and most advantageously 10 RMS or less. Under such conditions, filamentary polymeric material (8) is drawn and wound onto a package at speeds up to and including 6,000 meters per minute. For special convenience in operation and very advantageous results, the following relationships have been determined: V₁ = V₂, within the range 500 m/min to 3700 m/min; V₃ = V₄, within the range 1800 m/min to 4700 m/min; V₂ being in any event less than V₃. The filamentary polymeric material (8) is ordinarily treated with water or an appropriate standard finish composition before being stretched in a device according to the present invention.

[0015] Referring now to Fig. 3, there is shown the same embodiment depicted in Figs. 1 and 2, except that there are additional elements cooperating in the basic combination. In particular, sensing means (5), which is positioned downstream from the second roller.turret, detects any interruption in the moving threadline of the filamentary polymeric material (8). Such sensing means, which are usually based upon photoelectric, capacitance, or pneumatic principles, are readily available commercially. The output signal from such sensing means (5), which is indicated by the dotted line emanating therefrom, is transmitted to interrupting means (7), which stops the rotation of the individual motorized rollers and effects the return of the roller turrets to their first defined position, as set forth hereinabove. Such mechanisms are readily available commercially. In addition, the output signal from sensing means (5) may be transmitted to standard cutting means (6), which severs the threadline of the filamentary polymeric material (8), in order to prevent fouling of the motorized rollers and to facilitate a subsequent string-up procedure.

Claims

1. A device for drawing filamentary polymeric material characterised by a roller assembly (1) comprising at least three rollers (A,B,C,D), at least two of which are motorized, the rollers being spaced from each other in a first position providing for passage of filamentary polymeric material (8) in a straight line from a source of supply thereof through the space between the rollers (A,B,C,D,) and thence to a means for winding the filamentary polymeric material into a package on a support; and means for moving at least one of the rollers to a second position providing for contact of the filamentary polymeric material (8) with the surface of each motorized roller over a surface angle of less than 360°; whereby the filamentary polymeric material (8) adheres to the surfaces of the motorized rollers (A,B,C,D) without slippage and is drawn between the upstream (A,B) and downstream (C,D) motorized rollers when these rollers are caused to move into position, to effect string-up from source to take-up simply and without any operator exposure to moving rollers.

2. A device for drawing filamentary polymeric material, characterised by spaced apart first (1a) and second (1b) roller turrets (1) each comprising two motorized rollers (A,B;C,D) which rollers are spaced from each other by means of a cross-member (2) carrying the shafts (4) of the said rollers, the roller turrets (1) having a first position providing for passage of filamentary polymeric material (8) from a source of supply thereof through the space between the motorized rollers of the first turret (1a), through the space between the motorized rollers of the second turret (1b), and to a means for winding the filamentary . polymeric material into- a package on a support; and means for rotating each roller turret (1a,1b) in either a clockwise or counterclockwise direction through an angle less than 360° to a second position providing for contact of the filamentary polymeric material (8) with the surface of each motorized roller over a surface angle of less than 360 ; whereby the filamentary polymeric material (8) adheres to the surfaces of the motorized rollers (A,B;C,D) without slippage and is drawn between the first and second roller turrets when the motorized rollers are rotated to effected string-up from source to take-up simply and without any operator exposure to moving rollers.

3. A device as claimed in claim 2 in which the motorized rollers (A,B) of the first turret (1a) operate at a surface velocity of V₁ and V₂ respectively, and the motorized rollers (C,D) of the second turret (1b) operate at a surface velocity of V₃ and V₄ respectively, wherein V ≤ V₂, V₃ ≤ V₄ and V₂<V₃.

4. A device as claimed in claim 1, 2 or 3 in which the surfaces of the motorized roller or rollers (A,B;C,D) have a surface roughness height index value of 32 RMS or less.

5. A device as claimed in any of claims 1 to 4 in which the filamentary polymeric material (8) is wound into a package at speeds up to and including 6,000 meters per minute.

6. A device as claimed in claim 2 or any of claims 3 to 5 when dependent on claim 2 in which the roller turrets (1a,1b) are rotated from the first to the second defined position thereof through an angle of about 250°.

. 7. A device as claimed in claim 2 and any of claims 3 to 6 when dependent on claim 2 in which the first roller turret is rotated in a counterclockwise direction and the second roller turret is rotated in a clockwise direction.

8. A device as claimed in claim 2 or any of claims 3 to 7 when dependent on claim 2 in which the surface velocities of the motorized rollers are defined by the relationships: V₁ = V_2' V₃ = V₄, and V₂ < V₃.

9. A device as claimed in any preceding claim, in which sensing means (5) are provided downstream of the downstream motorized roller for the detection of a break in the moving threadline of the filamentary polymeric material (8), which sensing means (5) are coupled with interrupting means (7) for stopping the rotation of the motorized rollers (A,B:C,D) and returning the roller or rollers to the first defined position thereof.

10. A device as claimed in claim 9 when dependent on claim 2 or any of claims 3 to 8 when dependent on claim 2 in which the sensing means (5) are provided downstream of the second roller turret and the interrupting means (7) stops the motorized rollers (A,B;C,D) and returns the roller turrets (1a,1b) to the first defined position thereof.

Drawing