US2276797A

US2276797A - Thread covering apparatus

Info

Publication number: US2276797A
Application number: US352783A
Authority: US
Inventors: Otto W Schlums
Original assignee: Whitin Machine Works Inc
Current assignee: Whitin Machine Works Inc
Priority date: 1940-08-15
Filing date: 1940-08-15
Publication date: 1942-03-17
Anticipated expiration: 1959-03-17

Description

March 17, 1942. I

I THREAD COVERING APPARATUS O. W. SCHLUMS Filed Aug. 15, 1940 INVENTOR.

Ofta WJckh/w'.

Patented Mar. 17, 1942 UNITED STATESPATENT OFFICE THREAD COVERING APPARATUS Otto W. Schl ums, Whitinsville, Mass.,-assignor to Whitin Machine Works, Whitinsvillc, Mass, a corporation of Massachusetts Application August 15, 1940, Serial No. 352,783

3 Claims.

This invention relates to a method and apparatus for producing covered rubber thread by winding one or more covering threads about a tensioned rubber core thread. In order to produce satisfactory covered rubber thread, it is necessary that the thread be under uniform tension while it is being covered, so that uniform contraction may thereafter occur.

It is the general object of my present invention to provide'an improved method and apparatus for winding orcovering a rubber thread under substantially uniform tension.

To .the attainment of this object, I provide means to produce a predetermined stretch in the rubber thread as it is being covered, and I also provide means to entirely relax the rubber thread before it is thus stretched and tensioned for the covering. operation. In this way, the positively-actuated stretching or tensioning device will always produce the same tensioning result, which would not be the case if the rubber threads were under varying initial tension before stretching.

More specifically, I provide means for entirely relaxing the tension in the rubber core thread just before it enters the lower feed rolls of a covering machine.

My invention further relates to certain ordered I procedure and to certain arrangements and combinations of parts which will be hereinafter described and more particularly pointed out in the appended claims.

- A preferred form of the apparatus is shown 1 the drawing, in which Fig. 1 is a sectional. side elevation of thread covering apparatus embodying my improvements; I I

Fig. 2 is a detail front elevation, looking in the direction of the arrow 2 in Fig. 1; and

Fig. 3 is a similar view showing a slightly modifled construction.

Referring to Fig. 1, I have shown portions of a thread covering machine including a lower covering spindle l0 mounted on a fixed spindle rail II, an upper covering spindle l2 mounted on a fixed spindle rail H, a pair of lower feed rolls l5, and a pair ofupper feed rolls IS. The spindles l0 and i2 are provided with tubular center posts which are axially aligned and through which the rubber thread R isdrawn upward. The covering yarns Y and Y are sup plied fromspools S and S and the yarns are guided to the rubber thread R through rotatably mounted travelers T and T. The upper feed rolls it are driven at a somewhat higher ripheral speed than the lower feed rolls l5, so that the rubber thread R is given a predetermined stretch between the lower and upper feed rolls. As the thread is drawn upward, it first receives a winding of the yarn Y in one direction, and thereafter receives a second windingof the yarn Y. commonly in the opposite direction. The spindles l0 and I! may be driven by belts I8 and I9 from any suitable source of power.

The parts thus far described are or may be of a usual commercial construction and in themselves form no part of my present invention, which relates particularly to improved means for feeding the rubber thread R to the feed rolls IS in a relaxed condition.

The thread R is commonly supplied on spools 20 having peripheral contact with feed rolls 2| by which the thread is unwound. The thread R passes from the spool 20 to auxiliary feed rolls 30 which rotateat a slightly faster peripheral speed than the feed roll 2|, thus slightly tensioning the thread R as it is drawn from the spool 20. This slight tension is desirable to free the thread from the spool and to prevent catching or snarling thereof.

The thread R, as wound on the spool, is

commonly under some initial tension and it is desirable that this tension be entirely relaxed before the thread entersthe feed rolls I5, as

the initial tension in the thread may not be unirelax the thread between the feed rolls 30 and i the feed rolls l5 depends on the initial tension in the thread on the spool 20, on the speed ratio between the 'roller 2| and the rolls l5, and. also on the pressure applied to the thread between the feed rolls l5. g t

It is found that feed roll pressure on a rubber thread produces a kind of negative draft, so that the length of thread delivered by the feed rolls is less than the theoretical delivery calculated 7 from the peripheral speed of the rolls.

This negative draft, plus the decrease in speed of the rolls I5 with reference to the roll 2|, should substantially, equal the percentage of original tension in the thread on the spool 20, in order that the thread may hang in a free loop and that the loop may not substantially gain or lose.

Pressure-adjusting means, such as a spring 30'.

and adjusting screw ll is provided by which the pressure of the rolls I! may beslightly varied tions and satisfactory high grade covered rubber thread is thereby produced.

In Fig. 3 I have shown a slight modification in which the rubber thread is supplied'in' packages P which are supported-on a continuous feed roll ll. The operation is the same as previously described.

Having thus described my invention and the advantages thereof, I do not wish to be limited to the details herein disclosed, otherwise than as set forth in the claims, but what I claim is:

1. In a thread covering apparatus, means-to give a predetermined stretch to. a rubber thread, and means to impart a negative draft to the thread as it is delivered to said stretching means, said negative draft means including feed rolls operating under yielding pressure, and said negative draft being in such amount that the initial tension in the thread is removed and that the thread is fully relaxed as it is delivered to said stretching means.

2. The combination in thread covering apparatus as set forth in claim 1, in which means is provided to regulate the pressure of the feed rolls and thereby varythe negative draft.

3. In a thread covering apparatus, a roll to unwind tensioned rubber thread from a spool,

pressure rolls speeded to additionally tension the thread as it is unwound from the spool, feed rolls having less peripheral speed than said unwinding roll, means to apply pressure between said feed rolls, means to stretch the thread as it leaves the feed rolls and to maintain uniform stretch therein during the covering of the thread,

and means to winda covering thereon.

' o'rro w. scrum/rs.