Projectile or gripper shuttle loom with anti-ballooning cone for

Details Projectile or gripper shuttle loom with anti-ballooning cone for Projectile or gripper shuttle loom with anti-ballooning cone for

1996-05-13

1998-06-23

Falik, Andy

Textiles: weaving

Weft manipulation

Weaving with stationary weft supply

57 5883, 57354, 242 4701, 242128, 242157R, 139452, D03D 4734, B65H 5122

Patent

active

057691320

DESCRIPTION:

BRIEF SUMMARY
FIELD OF THE INVENTION

The present invention relates to a projectile or gripper shuttle loom having a weft-thread delivery unit which includes a stationary drum, a withdrawal eye and a yarn brake, and to a delivery unit having a storage drum from which weft yarn can be withdrawn through a yarn eye.


BACKGROUND OF THE RELATED ART

In a projectile loom known from U.S. Pat. No. 3,411,548 (FIGS. 1 to 5), the weft yarn is drawn from the drum below a cylindrical annular body, which encloses the face end of the drum, into the withdrawal eye which has arranged downstream thereof a controlled yarn brake. It is true that the annular body limits the size of the yarn balloon that forms during withdrawal, but only within a narrow axial range. A strong yarn balloon which performs braking, thereby increasing the tension level in the yarn in an inexpedient manner, is respectively formed in front and behind the annular body. Furthermore, when the yarn brake is being closed, the kinetic energy of the yarn balloon is released, whereby yarn is subsequently pulled from the windings on the drum until one or several loops of loose yarn are formed, resulting in disturbances during the next feeding operation, above all when these get caught on the annular body or on the withdrawal eye.
In a projectile loom known from DE-B-20 28 543, an internally smooth withdrawal cone is pulled on a delivery unit over a conical front nose of the drum with an intermediate spacing to limit ballooning. The withdrawal cone can be axially adjusted. The effect of the internally smooth withdrawal cone is not sufficient at the high yarn speeds in modern looms of this type. However, there might be formed a spatially limited balloon which in the cone stores a great length of yarn that relaxes upon braking, leading to the formation of loops and tangles.
Therefore, according to the above-mentioned U.S. Pat. No. 3,411,548 (FIGS. 8 to 13), it was already suggested about 30 years ago that an additional brake should be arranged on the drum, for instance a brush-type ring or a felt ring which touches the drum and fixes the yarn by clamping. This is supposed to counteract any subsequent pulling of yarn from the windings on the drum when kinetic energy is released in the yarn balloon after braking of the yarn by the controlled yarn clamp. However, such an additional brake on the drum has the serious disadvantage of a braking action which progressively increases considerably in response to the yarn speed and which inadmissibly increases the tension level in the yarn. That is why U.S. Pat. No. 3,411,548 provides for an axial temporary adjustment of the additional brake to reduce the influence thereof temporarily. Such a motional control is extremely troublesome and sluggish from a technical point of view because of the great masses to be moved.
Modern projectile looms operate at very high yarn speeds, e.g. up to 1500 m/min. Without an additional brake on the drum of the delivery unit, loops leading to frequent disturbances will be formed upon braking of the yarn by the controlled yarn clamp. Therefore, the provision of an additional brake on the drum, e.g. of the type shown in FIGS. 8 to 15 of U.S. Pat. No. 3,411,548, has generally been accepted in practice, the additional brake remaining, however, passive in a preselected position because an axial motional control of the additional brake can hardly be implemented technically in today's high-speed looms. The brake actively touches the drum with bristles, teeth or lamellae. The resultant yarn speed-dependent braking action, however, leads to an inacceptably high tension level in the yarn and is a cause for frequent yarn breakages and disturbances.
It is therefore the object of the present invention to provide a projectile or gripper shuttle loom as well as a delivery unit for such a loom wherein, despite high yarn speeds, the risk of operational malfunctions caused by loose yarn loops is considerably reduced.


SUMMARY OF THE INVENTION

This object is achieved by providing a hollow body over the storage drum which h

REFERENCES:
patent: 3411548 (1968-11-01), Pfarrwaller
patent: 3761031 (1973-09-01), Pfarrwaller
patent: 3848820 (1974-11-01), Stutz et al.
patent: 3958404 (1976-05-01), Kanai
patent: 3971522 (1976-07-01), Pfarrwaller
patent: 4367773 (1983-01-01), Newcomb

Affiliated with

Also associated with

Rating

Projectile or gripper shuttle loom with anti-ballooning cone for does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Projectile or gripper shuttle loom with anti-ballooning cone for, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Projectile or gripper shuttle loom with anti-ballooning cone for will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-1386032