US2688837A

US2688837A - Twisting head

Info

Publication number: US2688837A
Application number: US199171A
Authority: US
Inventors: Hadwich Fritz
Original assignee: Individual
Current assignee: Individual
Priority date: 1950-12-05
Filing date: 1950-12-05
Publication date: 1954-09-14
Anticipated expiration: 1971-09-14

Description

Patented Sept. 14,1954

UN IT E D STATES PAT E N T OFFICE TWISTING HEAD Fritz Hadwich, Bremen, Germany Application December 5,1950, Serial No. 199,171

7 Claims.

It is known to impart a permanent twist to the roving the spinning or twisting machines for use in the spinning of carded yarn and vicugna, by rotating the drawing rollers both about their own axes' and, as a pair, about the longitudinal axis of the yarn passing between them, so that the yarn is simultaneously drafted and twisted. Of the various devices which are available for this purpose, generally called twisting heads, none is entirely satisfactory with regard to constancy of pressure exerted by the drawing rollers.

Hitherto, the roller pressure necessary for ensuring that the roving is satisfactorily fed forward has almost always been produced by sprin pressure acting in opposition to the centrifugal force of the rotating drawing rollers, their bearings: and driving gear. This centrifugal force increases as the square of the circumferential velocity and the rotating masses are not inconsiderable. Therefore, as the driving speed increases, a critical speed is soon reached at which the force. of the spring: is no longer sufficient to overcome the centrifugal force. Beyond. that speed, the roller pressure decreases to zero, and there is then no longer any guarantee that the roving. will: be fed through the rollers and that the driving gears of the rollers will remain. appropriately engaged.

It has also been proposed: to press the drawing rollers. together exclusively by gravity; In such cases, additional disadvantages arise, including, in particular, unsatisfactory feeding of the roving when" vibrations are-set up.

In; all these devices one, at least, of the drawing rollers must have a movable mounting in order that the; spring pressure or gravity may be effective and the construction is thereby complicated.

Finally, it is known to mount the drawing rollers with their axes at a constant distance apart, the rollers being in the form of complementary cones so that the roller pressures may be varied. by moving one or both rollers in the axial direction. This, however, involves the use of a constant predetermined roller pressure, whereas. the yielding mounting of the drawing rollers has the advantage that the rollers can move apartsomewhat on anincrease in the thickness of theroving or if the roving contains lumps formed by dirt, snarls and soon, and thus ensure an-unimpeded passage for the roving.

In. accordance with the invention, the drawing rollers have fixed axes and are elastically constructed'. Thus, the rollers are rigidly mounted at a constant distance apart, so that the centrifugal force is absorbed by the mounting without detrimentally affecting the. roller pressure: once the latter has been adjusted. Owing to the fact that the drawing rollers are themselves elastic; for example by having an elastic core, thick spots in the roving are allowed for by'appropriate yielding. The speed at which the pair' of drawing rollers rotates about the longitudinal axis of the roving can" beselectedas desired and can bemade considerably greater than in the known devices because the roller pressure always remains constant irrespectiveof the centrifugal force, andthe smaller efiect of the weight of a roller can be disregarded.

When the twist-ing and drawing head according to the invention is employed, the spindle speed, and consequently the delivery speed; can be made considerably greater than in ring spinning machines comprising twist tubes, because the twisting and drawing head impart to the roving a permanent twist which is maintained" beyond thelower pair of drawing rollers and thus gives greater strength to theroving.

The mounting of the drawing rollers in accordance with the invention can be simply and reliably effected, and an adjusting device for the roller pressure may be provided, but such a device is not essential.

Elastic rollers are not new in themselves. They are already known in textile machines such as slip draft drawing frames used in worsted and cotton spinning, in which the bottom roller is rigid and the upper roller elastic. In the present case, the use of the novel elastic: rollers serves to solve the very special problem of rendering harmless the undesirable centrifugal forceslin the rapidly rotating. twisting and drawing head.

An embodiment of the invention is illustrated by way of example in the accompanying drawings, in which:

Figure 1 is'a vertical section through the drawing head.

Figure 2 is a plan of Figure 1 with the cover removed; and

Figure 3 is a longitudinal section through the pair of drawing rollers;

Fig. 4 is an enlarged detail sectional view of the means for adjusting the distance between the roll axes.

The housing I of the twisting'and drawing head is stationarily mounted on the spinning machine. Within this housing I, is a rotatable roller mounting 2' having ball bearings 3, 4; The ball bearing 3 lies at the bottom 50f the housing. I, while the ball bearing 4- is situated in the removable cover 6 and, when the cover is fitted, lies with its outer race. in. the top of the roller housing 2. Theremovable cover 6, which is secured by screws to the housing I, ensures ready assembly of, and: access to, the mechanism.

Rotatably mounted in the cover 6 by means of two ball bearings l is a tube 8, the bore of which tapers downwardly like a funnel spout and serves to guide the roving as it is fed to the nip. Keyed to the upper part of the tube 8 is a gear wheel 9 having inclined teeth and driven by a wheel Ill. The tube 8, below the cover 6, has fixed to it a bevel wheel I l for driving the pair of drawing rollers l2.

This pair of drawing rollers I2 is stationarily mounted within the mounting 2. The spindle 13 of the rollers l2 are carried in bearings [4, which are in the form of blocks mounted in corresponding guides in the roller mounting so that the distance between the rollers and consequently the roller pressure is adjustable. The fixed mounting of the drawing rollers I2 is obtained by providing a further bore in each of the bearings l4 transversely to and below the bore for the roller spindles l3. The two bores on the same side of the pair of drawing rollers are provided with right and left hand screw threads respectively and the distance between the drawing rollers l2, and consequently the roller pressure, can be adjusted by turning a threaded spindle l engaged in those bores, by means of its squared end [6. The two adjusting spindles l5 have in the center between the bearings 14, a collar H which lies between two webs l8 alongside the drawing rollers |2 when the latter are introduced into the roller mounting 2, whereby central positioning of the pair of drawing rollers in the mounting 2 is ensured. The drawing rollers which, together with their mounting, form an independent unit, are further held fast in the mounting 2 by two segmental covers l8 held in position by screws.

The drawing rollers I2 are of elastic construction. Two rings 20 of elastic material such as rubber are pushed on to the spindles l3 and are encased in a thin jacket2l. The jacket may be of thin steel or any material which in the form of a thin jacket is yieldable when backed by a resilient or rubber core. Jackets of steel or the like have the desirable property that the fibers of the roving do not adhere thereto. Bevel wheels 22 are mounted on diagonally opposite ends of the spindles l3 and come into engagement with the bevel wheel II when the cover 6 is screwed on. The bevel wheels 22 are preferably made of synthetic material.

A gear wheel 24 passes through a slot in the housing I and meshes with a gear wheel 23 on the roller mounting 2.

The device operates in the following manner:

The gear wheels l0 and 24 are driven by a driving device not shown. The tube 8 is rotated by the gear wheel I8 through the gear wheel 9, and in turn rotates the drawing rollers 12 in opposite directions through the gear wheels ll, 22. When the roller mounting 2 is stationary, the drawing rollers rotate only about their own horizontal axes (referring to Fig. 1) and the roving introduced from above through the tube 8 is drawn down between the drawing rollers 12. If the roller mounting 2 is at the same time rotated by the

gear wheels

24, 23,, the pair of drawing rollers 12 is also revolved about a vertical axis (referring to Fig. 1) and imparts a permanent twist to the roving. The speed of delivery and the drawing and twisting of the roving can be adjusted as desired by varying the speeds of the two drives of the gear wheels I0 and 24.

Owing to the fixed but adjustable mounting of the drawing rollers 12, no centrifugal forces can become effective and detrimentally influence the roller pressure. The elastic rollers automatically accommodate themselves to increases in the thickness of the roving. The necessary roller pressure is produced by appropriate close positioning of the drawing rollers in relation to one another by means of the adjusting spindles l5. Experience has shown that that pressure may be fairly low.

I claim:

1. A twisting head for textile spinning machines comprising a pair of spindles with drawing rollers thereon, means for pressing said rollers together to form a nip, means for rotating said rollers about their own axes, means for revolving said rollers as a pair about an axis perpendicular to their own axes, and means for guiding roving to said nip, and means for pre-,

venting movement of the axes of said rollers under the effect of centrifugal force, and means to enable said rollers to yield to accommodate passage through said nip of locally thickened portions in the roving while avoiding accumulation of fibers on their peripheries, comprising forming at least one of the rollers with a core. of resilient material and a peripheral jacket.

thereon to which the fibers do not adhere.

2. A twisting head as claimed in claim 1, comprising means for adjusting the distance between the axes of said rollers.

3. A twisting head as claimed in claim 2, in which said rollers are mounted in bearings having screw-threaded bores running transversely to the axes of said rollers and in which said adjusting means comprise screw-threaded spindles engaged in said bores.

4. A twisting head as claimed in claim 1, comprising bearings for said rollers in the form of blocks, and a mounting for said rollers formed with emplacements for said bearing blocks, said mounting and said rollers being mounted for rotation as a unit.

5. A twisting head as claimed in claim 1, in which said roller structure comprises a spindle, on which is mounted the core of resilient material, and the jacket being of thin-hard sheet material.

6. A twisting head as claimed in claiml, in which said roller structure comprises a spindle, and the core is of rubber.

'7. A twisting head as claimed in claim 1, in which said roller structure comprises a spindle, the core comprises a pair of disc-like cores of rubber mounted side-by-side on said spindle and the jacket on said cores is of thin-hard sheet material.

References Cited in the file of this patent UNITED STATES PATENTS- Number Name Date 31,031 Plummer Jan. 1, 1861 56,258 Parmelee July 10, 1866 88,375 Goulding Oct. 27, 1868 532,255 Whitney Jan. 8, 1895 571,415 Toye Nov. 1'7, 1896 1,830,728 Weise Nov. 3, 1931 2,307,821 Campbell Jan. 12, 1943 FOREIGN PATENTS Number Country Date 452,048 Great Britain Aug. 1'7, 1936