US3633808A

US3633808A - Nozzle for jet looms

Info

Publication number: US3633808A
Application number: US42764A
Authority: US
Inventors: Vladimir Svaty
Original assignee: Elitex Zavody Textilniho
Current assignee: Elitex Zavody Textilniho
Priority date: 1969-06-06
Filing date: 1970-06-02
Publication date: 1972-01-11
Anticipated expiration: 1989-01-11
Also published as: JPS49427B1

Abstract

A nozzle provided with a body having a bore, a piston mounted in the body bore, the piston having a bore, and a yarn carrier mounted in the piston face. The carrier has a smaller dimension than the piston bore to define an annular orifice. The piston and body are formed with cooperating engaging surfaces forming a valve seat. The piston is provided with channels connecting the surface to the piston bore. Means are provided for forcing a fluid between the engaging surfaces, opening the valve seat and allowing the fluid to flow out of the annular orifice.

Description

United States Patent 113,633,868

[72] inventor Vladimir Svaty [56] Relerences Cited Libel-is, Czechoslovakia UNITED STATES PATENTS g5 s i 2 1970 2,812,850 11/1957 Pape 226/97 a 2:3 1972 3,485,428 12/1969 Jackson 226/97 t [73] Assignee Elitex, zavody textilnlho shojirensti Primary Examiner-Richard Schachef generalni redhel to Attorneys-Richard Low and Murray Schaffer Liberic, Czechoslovakia [32] pnomy Jun. 1969 ABSTRACT: A nozzle rovided with a body havin a bore, a [3 3 Czechoslovakia P 8 [31] Pv 401$ piston mounted in the body bore, the piston having a bore, and a yarn carrier mounted in the piston face. The carrier has a smaller dimension than the piston bore to define an annular [54] NOZZLE FOR JET LOOMS orifice. The piston and body are formed with cooperating en- 8 Claims, 1 Drawing Fig. gaging surfaces forming a valve selgt. The piston is provided with c annels connecting t e an ace to the piston bore. [52] U.S.Cl 4 2232964370, Means are provided for forcing a fluid between the engaging lm Cl I surfaces, opening the valve seat and allowing the fluid to flow 501 Field 61 Search 226/7, 97; m annulamrfim 239/4i0,4ll,4i6.5;28/l.4

if A

PATENTED mu 1 1972 3.633; 808

INVENTOR VLHDImm SWAT BY NOZZLE FOR JET LOOMS BACKGROUND OF THE INVENTION The present invention relates to a nozzle for jet weaving looms, and in particular to a nozzle in which the pressure fluid ejected therefrom surrounds the weft yarn to be inserted and inserts and weft yarn further into the shed.

At present, two nozzle types are known which differ prin cipally only in their construction. The first type is the so-called open nozzle" which is made of two concentric bodies rigidly mounted together. The mouth of this nozzle is always open and the actual control and interruption of the fluid flow is performed in the pumping device supplying the jet stream.

The other conventional nozzle is called the closed nozzle" having a valve situated in the nozzle which interrupts the fluid flow, thus maintaining a constant pressure in the pipeline between the nozzle and the pumping device. The nozzle is generally formed of an outer body and an inner cone.

The two conventional nozzles are well known, as is their advantages and disadvantages. The advantage of the open nozzle" consists in its simple manufacture and the ability for its relatively accurate adjustment of the annulus between the two concentrically arranged bodies.

On the other hand, an important disadvantage consists in that at the beginning of the insertion yarn, the jet flows slower than during the subsequent full insertion. Also, at the end of the ejection, the velocity of the jet is reduced. Thus, there are two passages at the beginning and at the end of the ejection, when the pressure in the pipeline is reduced resulting in the obvious reduction of the velocity of the water thereupon. This gradual increase and decrease of pressure in the open nozzle causes some difficulty, particularly in that the consumption of water for the weft yarn insertion is excessive creating drying or flow down from the nozzle and an excessive splatter of fluid about the machine.

The closed nozzle does not have this disadvantage, as the orifice of the nozzle is opened only at the moment at which the pressure in the pipeline rises to a predetermined value and thereafter the nozzle is automatically closed. This nozzle is, however, more complicated in its manufacture and it is therefore much more difficult to create the proper concentric annulus between the nozzle body and its inner conical member. Simultaneously, the closed nozzle has a great disadvantage in that the closing valve seat directly forms the water jet so that pressure variation in the pump fluid may cause changes in the water jet and vibration of the closing cone. At the same time, there is the danger that the valve seat becomes worn out, also unfavorably influencing the jet.

Both systems, i.e., the open" and the closed" nozzle can be combined in various manners with a pump, so that the nozzles and the pump constitute an integral assembly. Such a combined device has, however, two other disadvantages, in that it is still more difficult to maintain in accurate coaxial arrangement, and it is particularly difficult to suitably adjust the nozzle for inserting the weft through the shed which is necessary for various kinds of weft.

For the reasons given above, a construction is required which constitutes accurate and guaranteed conditions at the exit orifice of the nozzle, securing also a reliable closing of the liquid in close proximity to the ejecting opening of the nozzle. Furthermore, a device is required which would insure the correct course of the pressure in the nozzle to which the pumping device may feed the liquid. It is also advantageous from the viewpoint of weft insertion that the velocity of the liquid should be higher at the beginning of the jet than at the end. Simultaneously, it is also necessary for the weft yarn insertion that the nozzle should provide a very smooth flow, i.e., a flow with a reduced velocity of the liquid. This so-called smooth flow acts to maintain the tension of the weft yarn between the measuring mechanism and the jet and prevents the yarn from elastically reversing itself after its vigorous insertion into the shed.

The object of the present invention is to mitigate all abovementioned disadvantages and to constitute such a nozzle, which would meet the above said high requirements.

SUMMARY OF THE INVENTION According to the present invention, a nozzle is provided comprising a body having a bore, a piston mounted in the body bore, the piston having a bore, a yarn carrier mounted in the piston face. The carrier has a smaller dimension than the piston bore to define an annular orifice. The piston and body are formed with cooperating engaging surfaces forming a valve seat. The piston is provided with channels connecting the surface to the piston bore. Means are provided for forcing a fluid between the engaging surfaces, opening the valve seat and allowing the fluid to flow out of the annular orifice.

Preferably, the piston bore and the yarn carrier are conically shaped, the carrier being mounted securely within the piston bore. The body of a piston is also provided with cooperating portions forming a cavity surrounding the engaging surfaces. Spacer means of predetermined length are located within the cavity to determine the extent of engagement of the piston and body.

Full details of the present invention and illustrations of its objects and advantages are set forth in the following description.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawing is a schematic cross section of the nozzle, formed in accordance with the present invention, attached to a fluid-pumping device.

DESCRIPTION As seen in the FIGURE, the nozzle of the present invention comprises a body having a generally cylindrical interior bore, the rear end of which is provided with a spaced axially inwardly directed rim 3 defining a circular space 12. Movably mounted within the bore is a piston 2, the circumferential exterior extremity of which slides against the interior surface of the body 1. The piston 2 itself is provided with an axially extending interior bore of general conical cross section and an exterior having a pair of stepped shoulders 3 and 4.

An annular collecting groove 5 or assembly surface is formed on the inner edge of the smaller step 3' forming a bypass groove communicating by means of a plurality of inwardly directed inclined centripetal channels 6 with an expanded funnel shape hollow portion 7 in the interior bore of the piston 2, so that fluid can be debouched therein. A yarn carrying cone 8 having an axial opening 9 adapted to receive a not shown weft is mounted centrically within the conical interior bore of the piston 2. The cone 8 is preferably force fit in the rearmost portion of the piston bore, i.e., behind the funnel portion 7 and is tapered to cross section smaller than the forward end of piston bore so as to form an annular orifice directed outwardly of the front end of the body 1. Conventional fastening means may be employed to secure the cone 8 within the piston if desired.

The collecting groove 5 is formed on the smaller step 3 which constitutes, together with the oppositely located surface of the inner rim 3, a circular valve seat. The contact of the valve surfaces 3 and 3 is normally secured by rubber annular pressure spring 10 which is adapted to bear against the front surface of the piston 2. A nut 20 threaded to the front exterior edge of the body 1 secures the pressure spring 10 permits easy adjustment of its resilient bias.

The larger piston step 4 is spaced from and constitutes, together with the opposite circular space 12, in'the body 1, an annular feed cavity 13 which surrounds the circular seat 3 and 3'. The annular feed cavity 13 is connected by means of a conduit 14 and a one-way ball valve 15 to a source of pressurized fluid which may, for example, comprise a conventional singleacting pump 16, which feeds an amount synchronously of the weft inserting pressure fluid, which is, in the present case,

preferably liquid. The pump 16 is connected by conventional means to the weaving loom drive apparatus so that it will be operable in time and cyclical relationship thereto.

In the annular feed cavity 13, a perforated spacer ring 17, acting as a filter, is arranged which, as will be explained later, may also be used in particular cases to adjust the distance between the step 3' of the piston 2 and the opposite surface 3' of the body 1.

The piston 2 is sealed in the body 1 by two rings l8, l9 lodged in suitable retaining grooves.

The device specified above operates as follows:

The pumping device 16 periodically feeds pressurized fluid to the annular feed cavity 13 where it acts according to the known principle of pressure propagation in liquids and gases upon the stepped shoulder 4 of the piston 2. The piston 2 is thus urged to press against the rubber spring 10 carrying with it the cone 8. At the moment at which the pressure of the liquid overcomes the force of the rubber spring 10, the valve seat 3, 3 is opened and the liquid flows into the now accessible collecting surface 5 through the centripetal channels 6 into the funnel-shaped hollow 7, from whence the liquid is ejected in the form of an annular column in the general direction of the arrow A. A weft yarn which is admitted through the rear of the opening 9 may be thus inserted, for example, into a not shown shed.

The advantage of the arrangement of the nozzle according to the present invention consists particularly in that because the piston 2 and cone 8 move together the orifice annulus between the piston 2 and the cone 8 is rigidly adjusted and independent of the liquid pressure. Thus, the nozzle has the advantage of the open nozzle in that the annulus may be accurately preadjusted and its manufacture also inexpensive. The present construction on the other hand does not have the disadvantage of the open nozzle, as the pressure in the pipeline remains normally closed by action of the pressure spring 10 and ball valve 15. Above all, the fluid ejection begins only at full speed since the valve seat surfaces 3 and 3' only open after a predetermined pressure is reached.

For the prevailing majority of cases, the operation of the nozzle as specified above is the most advantageous. lf, however, in individual cases where a completely open nozzle is preferred, the nozzle can be changed in a very easy manner. It is sufficient only to insert into the annular feed cavity 13 a spacer 17, the dimension of which does not permit the full closing of the circular seat 3, 3. The said spacer 17 can be also used as a filter, but maintains fluid flow continuously out of the piston annulus.

If the operation of the nozzle according to the present invention is considered in detail, the following important advantages will be apparent:

When the operating liquid flows into the annular feed cavity 13, at the predetermined pressure, the piston is caused to move against the rubber spring 10, thus increasing the liquid supply in the cavity 13. Upon closing the nozzle, i.e., when the liquid pressure of the liquid fed by the pumping device 16 drops below the predetermined level, the liquid supply is again forced out through the valve seat 3,3 into the annular orifice of the nozzle, thus causing a liquid jet having a lower pressure to be expelled, creating the so-called smooth flow at the end of the ejection cycle.

The piston body 2 can be selectively graded in size by choosing precisely the piston surface against which the liquid is pressed and the strength and size of the rubber spring. Con sequently, the sensitivity of the nozzle to pressure variation can be determined and forces acting outside the nozzle axis can be eliminated, thus avoiding undesirable wear of the movable parts and similar failures.

Besides their actual function, the arrangement of the separate parts of the nozzle is also important. Normally, little attention need be paid to the manufacturing conditions which are of course indispensably necessary for manufacture of very fine mechanisms In the arrangement of the nozzle according to the present invention, a simple conical opening is made in the piston body, which opening can be accurate y machined and into which the cone of the nozzle can be force fit. Also the cone 8 is easily manufactured as it is not provided with any threads and can be easily removed from the piston body 2, this being particularly important for the cleaning of the nozzle.

Various modifications and changes will, of course, be obvious to those skilled in the art. The present specification is, therefore, to be taken as illustrative only of the invention and not at all limiting.

What is claimed:

1. A nozzle for a fluid jet weaving loom in which pressurized fluid is employed to eject a yarn comprising a body having an axially extending bore, a piston movably mounted in said body bore, said piston having an axially extending bore, a carrier mounted in said piston bore, said carrier having an axial bore for supporting a yarn and an exterior surface spaced from the interior surface of said piston bore to form an annular orifice therebetween, said body and said piston having cooperating engaging surfaces adapted to form a seal therebetween, means for normally urging said body and piston surfaces in sealing engagement, channel means extending between the engaging surface of said piston and the annular orifice, and means for forcing fluid under pressure between engaging surfaces to cause fluid to flow through said channels into said orifice.

2. The nozzle according to claim 1, wherein the engaging surface of the piston is formed with an annular groove for collecting fluid therein, said groove communicating with said channels.

3. The nozzle according to claim 1, wherein the bore of said piston is provided with a radially extended hollow portion midway its length, and is conically shaped, the carrier being correspondingly conically shaped having an outer dimension conforming to that of the piston bore axially behind the hollow portion and smaller than that of the piston bore axially ahead of said hollow portion, said smaller portion defining one wall of an axially tapering conical annulus orifice.

4. The nozzle according to claim 1, wherein the exterior of the piston is provided with at least two stepped shoulders, one of which cooperates with an oppositely arranged internal rim in said body to form the engaging surfaces and the other constitutes in cooperation with an opposite surface of said body an annular cavity surrounding said surfaces.

5. The nozzle according to claim 4, including a source of pressurized fluid, a conduit connecting said source to the annular cavity, one way valve means located in said conduit, and means for cyclically feeding said fluid to said cavity.

6. The nozzle according to claim 4, including a spacer ring located within said cavity bridging the other of the opposed surfaces, said ring having an axial length of predetermined distance to regulate the engagement of the engaging surfaces.

7. The nozzle according to claim 1, wherein said means for urging said piston into engagement with said body comprises an annular resilient compression ring.

8. The nozzle according to claim 7, wherein said ring is rubber.

Claims

8. The nozzle according to claim 7, wherein said ring is rubber.