US3722552A

US3722552A - Hydraulic weft inserter drive in weaving machines

Info

Publication number: US3722552A
Application number: US00162344A
Authority: US
Inventors: J Indra; V Opatril
Original assignee: Elitex Zavody Textilniho
Current assignee: Elitex Zavody Textilniho
Priority date: 1970-07-17
Filing date: 1971-07-14
Publication date: 1973-03-27
Anticipated expiration: 1990-03-27
Also published as: DE2130863A1; FR2099432A1; CS151906B1

Abstract

The present invention relates to hydraulic weft inserter drives for weaving looms. Each of a pair of hydraulic units is located at opposite ends of a guideway along which the weft inserter is slidably movable. Each hydraulic unit contains a piston whose shaft is extendable in a direction along the guideway in a direction along the guideway on the application of hydraulic pressure on the piston in its normally retracted state. A double pump is operated in synchronism with the loom, each half of the pump being connected to a corresponding hydraulic unit, in such a way that hydraulic pressure is alternately applied to each of the hydraulic units by out of phase operation of each of the pump halves. Biased to retract inside the hydraulic units, the driving pistons of the corresponding hydraulic units are alternately extended, each driving piston being extended in an opposite direction along the guideway, to contact the weft inserter and urge it to move towards the other end of the guideway.

Description

United States Patent 1 Indra et al.

[54] HYDRAULIC WEFTINSERTER DRIVE IN WEAVING MACHINES [75] Inventors: Jaromir Indra; Vaclav Opatril, both of Brno, Czechoslovakia [73] Assignee: Elitex, Zavody Textilniho Strojirenstvi Generalni Rediteislvi, Liberec, Czechoslovakia [22] Filed: July 14, 1971 [21] Appl. No.: 162,344

I [30] Foreign Application Priority Data [58] Field of Search ..60/51, 52, 53; 139/142, 144

[5 6] References Cited UNITED STATES PATENTS 2,537,895 1/1951 Hicks ....l39/144 2,231,331 2/1941 Griffith et al.... ....60/51 3,436,913 4/1969 Muller et a1. ....60/51 3,330,305 7/1967 Svaty et al. ..139/144 1 1 Mar. 27, 1973 Primary Examinerl-lenry S. Jaudon Att0rneyMichael S. Striker 57 ABSTRACT The present invention relates to hydraulic weft inserter drives for weaving looms.

Each of a pair of hydraulic units is located at opposite ends of a guideway along which the weft inserter is slidably movable. Each hydraulic unit contains a piston whose shaft is extendable in a direction along the guideway in a direction along the guideway on the application of hydraulic pressure on the piston in its normally retracted state. A double pump is operated in synchronism with the loom, each half of the pump being connected to a corresponding hydraulic unit, in such a way that hydraulic pressure is alternately applied to each of the hydraulic units by out of phase operation of each-of the pump halves. Biased to retract inside the hydraulic units, the driving pistons of the corresponding hydraulic units are alternately extended, each driving piston being extended in an opposite direction along the guideway, to contact the weft inserter and urge it to move towards the other end of the guideway.

11 Claims, 1 Drawing Figure PASTA V0? HYDRAULIC WEFT INSERTER DRIVE IN WEAVING MACHINES BACKGROUND OF THE INVENTION 1 Field of the Invention This invention relates to hydraulic drives, and particularly to a hydraulic weft inserter drive used in a weaving loom.

2. Description of the Prior Art In the past, it has been customary to drive weft inserters either mechanically by means of an inserting arm, or by means of a piston mechanism operating with compressed pair usually fed by a twin pump.

In the case where weft inserters are driven by means of compressed air, piston rods are arranged in the two working cylinders mounted at the sides of the weaving machines, said piston rods being provided at their front ends with recesses, which are engaged by collets, which are always released at a predetermined moment which enable free movement of said piston rod, which is acted upon laterally by depressed air.

In both cases, the pertinent device is complicated, noisy during operation and shows, moreover, a considerable liability, causing frequent breakdowns which result in expensive stops of the machine.

SUMMARY OF THE INVENTION The present invention aims at overcoming the disadvantages of the prior art devices. A hydraulic drive as contemplated by the present invention results in the reliable picking of the weft inserters, the working elements on the extreme positions of the path along which the weft inserter travels, being hydraulic units. The use of a twin hydraulic pump feeding two hydraulic units, one at each end of the path of travel of the weft inserter, results in a reliable and quiet operation, there being almost no mechanical elements which can break down after repeated operations.

In accordance with this invention, a component is slidably mounted for movement in a predetermined path between the two positions along a guideway. A pair of hydraulic units are located at opposite ends of said path. Each hydraulic unit consists of a cylinder and a normally retracted driving piston whose shaft is extensible in a direction along the guideway towards the other hydraulic unit. The component is provided with surfaces to enable abutting contact with the ends of the shafts of the driving pistons at each end of the guideway. Although not required, the component moves between the extreme ends of the guideway and comes to rest thereon in preparation for action on it by the respective piston of a hydraulic unit located on the end where it has come to a stop. A pair of hydraulic pumps are provided, each one of said pumps being connected to one of the respective hydraulic units. The pumps are operated out of phase so that liquid pressure is alternately supplied to the hydraulic units so that pressure is thereby alternately applied to the driving piston inside said cylinders. Application of liquid pressure on a cylinder causes it to extend from its normally retracted position, come into abutting contact with one of the surfaces of the component provided therefor, and slidably move the component a distance which corresponds to the fully extended position of the driving piston. Withthis arrangement, the liquid pressure is removed from the driving piston, the driving piston returned to its retracted position and the component comes to a stop along the guideway. With this arrangement, the pump which now feeds the hydraulic unit positioned on the side of the guideway where the component has come to a stop, comes into play and initiates a liquid pressure buildup in this latter hydraulic unit likewise causing extension of its respective driving piston. The component is thereby slidably moved back to its initial position and the reciprocating movement of the component continues so long as the twin pumps are kept in operation.

The novel features which are considered as characteristic of the invention are set forth in particular in the dependent claim. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWING The FIGURE shows a hydraulic press according to the present invention, partly in a diagrammatic form, shown two hydraulic units on opposite ends of a guideway and a double pump feeding said hydraulic units.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawing, a hydraulic drive mechanism is shown to comprise a pair of hydraulic units 100, located at opposite ends of a guideway 23 defining a predetermined path. For purposes of specifically describing the invention, the invention will be described in conjunction with a weaving loom wherein the invention is utilized to shuttle a weft inserter in a reciprocating motion along a predetermined path. Thus, component 22 will, in this connection, be the weft inserter of the weaving loom. Accordingly, weft inserter 22, to be shuttled in a reciprocating fashion along guideway 23, moves between two end positions on said predetermined path.

A hydraulic unit is situated at each end of the guideway 23. Each hydraulic unit 100 consists of a body or cylinder 17 which is provided with a hollow portion or cavity 17. A driving piston 18 is contained within the body 17 of hydraulic unit 100, the shaft or piston rod of said driving piston extending through body 17 so as to be slidably mounted thereon. A spring 19, which is mounted on the shaft of driving piston 18, rests on one end against the head of driving piston 18 and on the inside wall of body 17 as shown, so as to urge the driving piston 18 to a retracted state into body 17 in the normal state when no other pressures are applied to said piston 18. Driving piston 18 is capable of slidable movement with its shaft in a direction opposing the biasing of spring 19, the shaft of driving piston 18 extending in a direction generally along guideway 23. The hydraulic units 100 on both ends of guideway 23 operate in substantially the same way except that their respective pistons move in opposite directions as said pistons move away from their normally retracted positions. Thus, each piston rod projects along guideway 23 in a direction towards the other of said hydraulic units 100 when the restrictive piston moves away from the retracted position. A component, or the weft inserter in this case, is provided with surfaces for abutting contact with the ends of the shafts of pistons 18. Thus, extension of said shafts result in contact with said surfaces of said weft inserter and sliding movement of the latter along said guideway as will hereinafter be described.

A twin pump assembly 200 is shown to consist of a body or housing 1 and provided with two similar hydraulic pumps. Each pump is provided with a piston 2 which is carried by a piston lifter 4. Means 3 are provided between said housing 1 and said piston 2 for urging said piston 2 into a retracted state and against piston lifter 4. Each piston lifter 4 is in turn slidably mounted within housing 1 and connected to a roller 5 which is rotatably mounted within the arms of piston 4 lifter as shown. Roller 5, and therefore piston lifter 4, rides on cam means 6 which is rigidly secured to cam shaft 7. Thus, by rotation of cam shaft 7, cam 6 causes piston lifter 4 to slide up and down within housing 1 in accordance with the shape of cam 6. It is not critical what means are used to rotate cam shaft 7, however, in this application cam shaft 7 is preferably connected to the weaving loom which incorporates the weft inserter to be reciprocated. In this connection, and for reasons which will become clear in the balance of this disclosure, it is preferred that the cam shaft 7 make one revolution for every operating cycle of the loom. It will be noted in the FIGURE, that the piston 2 on the left side of housing 1 is slightly in extended position while the other piston on the right side of housing 1 is in a more retracted state. As will soon become clear, effec tive operation of the hydraulic drive according to this invention is most effective when the two pistons do not operate in synchronism, that is when the two pistons are both extended or retracted at the same time. In fact, and in connection with a weft inserter for a weaving loom, it is preferred that the pistons 2 move in synchronism but out of phase by difference of 180 so that when one of the pistons 2 is attaining its fully extended position the other of the pistons 2 is just reaching its fully retracted position. This is accomplished by selecting the shapes and arranging the cams 6 so as to lift rollers 5 in such out of phase relationship.

The pistons 2 are shown to be slidably mounted within cavities 14 provided in housing 1. An annular recess 8 is provided near the top of each piston 2 so as to provide a narrowed portion. A series of channels are provided in piston 2 for communicating liquid from working spaces 14' on top of pistons 2 and annular recesses 8. This is accomplished by providing an axial channel which extends from the top of piston 2 down into the narrowed portion of piston 2 in the vicinity of annular recess 8 and a radial channel 9 which is in communication with radial channel 10 and extends throughout the narrowed portion of piston 2 and opens into annular recess 8.

Hydraulic units 100 are connected to the working spaces 14' by means of pump pipe lines 16 which lead to openings 16' of the hydraulic units 100. Cavities 14 are also in liquid communication with areservoir 25 which-contains hydraulic fluid. Thus, reservoir pipeline 1] is connected to vertical inlet channel 12 of housing 1 which is provided between the two cavities l4 and extends somewhat beyond the tops of cavities l4. Horizontal channel 13 is provided which is in communication with vertical inlet channel 12 and opens on each side into each of the cavities 14. In this way, hydraulic fluid can be supplied from the liquid reservoir 25 into the individual cavities 14 as required. With this arrangement, hydraulic fluid generally flows from reservoir 25 into cavities 14 by way of inlet channel 12 and is forced out by pistons 2 through outlet channels 15 where it proceeds through openings 16' into hydraulie units 100. Partly for the reason of providing a closed circuit for the flow of hydraulic fluid, adjustable throttle valves 20 are provided on hydraylic units which communicate the interior portions 17' thereof with valve pipelines 21 which lead to liquid reservoir 25.

As just described, throttle valves 20 provide an escape means to hydraulic fluid contained within hollow cavities 17 of hydraulic units 100. In addition to allowing pressurized hydraulic fluid to escape, adjustment of throttling nozzle 20 also serves the purpose of regulating the necessary stroke of driving piston 18. Thus, by closing up throttle valve 20, less hydraulic fluid is permitted to escape and the overall stroke or the distance travelled by driving piston 18 during the entire extension step will be small. On the other hand opening up throttle valve 20 will have the opposite effect. Thus, a larger throttle valve opening will permit more hydraulic fluid to escape through valve pipeline 21 into reservoir 25 This will permit more hydraulic fluid to enter through opening 16', and consequently driving piston 18 will advance further under these conditions. Another purpose of throttle valve 20 is that, by admitting a small volume of liquid during each discharge into the liquid reservoir, a constant circulation of liquid between piston 2 and the cavity 17' in body 17 is made possible, whereby heating of the compressed liquid is prevented.

A weft inserter 22, therefore, is mounted adjacent to the projecting ends of driving pistons 18, said weft inserter being movable along guideway 23. At each extreme position of weft inserter 22, a device 24 for reversing the weft inserter is mounted, said device being of known construction. This known device is not the subject of the present invention and therefore not further specified.

The device as specified above operates as follows:

The cam shaft 7 of the pump is driven from a driving mechanism of a weaving loom at such a speed, that during one operating cycle of the loom one revolution of the cam shaft 7 is completed. During rotation of cam shaft 7, cam 6 contacts roller 5 of the piston lifter 4, piston 2 begins to move upwards and pushes the liquid out of working space 14. In the first phase of the discharge stroke, the liquid escapes through an open channel 13 back into the liquid reservoir. Only from the moment at which the upper edge of piston 2 covers the upper end of channel 13, the liquid is discharged from the working space through pipeline 16 into the hollow in body 17, where it acts by its pressure upon driving a piston 18. Due to pressure of the transferred liquid, driving piston 18 is ejected against weft inserter 22 which has imparted motion thereupon. The discharge of the liquid from the working space 14' in the hollow body 17, and thus the driving motion of driving piston 18, lasts until the upper end of the annular recess 8 on piston 2 uncovers channel 13. From that moment, during the stroke of piston 2 until its upper dead center the discharged liquid by means of piston 2 escapes from the working space 14' nearly without resistance through channels and 9 and through the annular recess 8 into channel 13 and therefrom through channel 12 and the pipeline 11 attached thereto back to the liquid reservoir, whereupon the pressure of liquid in the working space 14' and in the hollow of body 17 rapidly drops, whereupon the driving piston 18 is stopped.

In the course of the effective discharge of liquid from the working space 14' into the hollow 17' in body 17, a small part of the liquid escapes through throttle valve 20 in pipelines 21 and 11 back into the liquid reservoir. The quantity of liquid thus escaped is determined by the cross-sectional area of flow of throttle valve 20.

Upon further rotation motion of cam shaft 7, as soon as roller 5 begins to move along the dependent parts of cam 6, piston 2 together with the piston lifter 4 is returned downwards by action of the prestressed spring 3. The increasing working space 14' is now being filled by liquid flowing thereto from the hollow of 17' of body 17 due to the back movement of driving piston 18 caused by the prestressed spring 19 until driving piston 18 attains its retracted position. Upon further movement of piston 2 in the downward direction, the volume of liquid which has escaped in the course of the effective discharge stroke through the throttling valve 20 is replaced, after uncovering the channel 13 by the upper end of piston 2, by liquid fed from the liquid reservoir.

In the manner as specified above, driving pistons 18 impart to the weft inserter 22 such impulses, that said weft inserter moves in a reciprocating fashion between positions determined by the distances to which the driving pistons 18 extend. Once the weft inserter 22 is moved into a position by one of the driving pistons 18, the motion of the weft inserter 22 is reversed by action of device 24. Shortly afterwards, the cam of the other piston imparts the discharge stroke thereto, whereupon the driving piston 18 at the opposite end of the machine imparts a back movement to the weft inserter 22. After arrival of the weft inserter 22 into the original position, said weft inserter is again reversed by means of device 24 and shortly afterwards, the cam of the first piston 2 imparts the discharge stroke thereto and the weft inserter 22 is ejected again upon action of driving piston 18 into its other extreme position. This reciprocating motion continues during the entire operation of the loom.

While the invention has been illustrated and described as embodied in a hydraulic drive for weft insertion in weaving looms, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present inventron.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims.

We claim:

l. A hydraulic drive, particularly for weft insertion in weaving looms, comprising a component movable in a predetermined path between two positions; a pair of hydraulic units respectively located at opposite ends of said path and each comprising a cylinder and normally retracted piston means movable in the direction towards the other unit for movement of said component in said path; pump means comprising two independent pumps for respectively supplying liquid under pressure to said cylinders; and drive means for driving said two pumps out of phase with each other to thereby alternatingly moving said piston means of one unit towards the other unit so as to move said component between said positions thereof.

2. A hydraulic device as defined in claim 1, and including a pair of uninterrupted pump pipe lines respectively connecting said two pumps with the respective cylinders of said unit.

3. A hydraulic drive, particularly for weft insertion in a weaving loom, comprising a component movable in a predetermined path between two positions; a pair of hydraulic units respectively located at opposite ends of said path and each comprising a cylinder and normally retracted piston means movable in the direction towards the other unit for movement of said component in said path; pump means comprising two independent pumps respectively connected to said cylinders of the unit for alternatingly supplying liquid under pressure into the respective cylinder to move the associated piston means toward the other unit and thereby said component between the positions thereof, each of said pumps comprising a pump cylinder, a normally retracted pump piston movable in said cylinder between two positions one of which is a fully retracted position in the charging stroke of said pump and the other of which is a fully extended position in the discharging stroke of said pump; power means for moving said pump pistons in the respective pump cylinders in out of phase relationship with respect to each other; and a pair of pump pipe lines respectively connecting said pumps to said hydraulic units.

4. A hydraulic drive as in claim 3, wherein said component is a weft inserter in a weaving loom and wherein said power means consists of a pair of cams, mounted on a rotating weaving loom shaft, the cams being rotated and rigidly mounted on said shaft so as to be displaced by 180 relative to one another, and lifting means supporting said pump pistons and riding on said cams in the respective pump for following said cams and lifting said pump pistons from their retracted positions.

5. A hydraulic drive as in claim 4, wherein each pump piston completes a charging and a discharging stroke for each 360 revolution of said loom shaft.

6. A hydraulic drive as in claim 4, wherein said loom shaft completes a 360 revolution for each operating cycle of the weaving loom.

7. A hydraulic drive as in claim 3, wherein each pump piston is provided in its upper part with a radial annular recess, a radial channel in said pump piston opening into the annular recess, and an axial channel communicating with the radial channel and extending from the radial channel through the pump piston to the top end of said pump piston and opening in a working space above said pump piston in the associated pump cylinder.

8. A hydraulic drive as in claim 7, wherein outlet channels are provided for expelling hydraulic fluid in the discharge stroke of said pump pistons; and pump pipelines, connected to said outlet channels, provided from conducting the expelled hydraulic fluid to said hydraulic units.

9. A hydraulic drive as in claim 8, further having a reservoir for hydraulic fluid; and an inlet channel in the side of each of said pump cylinders, communicating with the working spaces near the tops of said pump cylinders at points just above the tops of said pump pistons when they are in their extreme charging stroke positions, which are connected to said reservoir.

10. A hydraulic drive as in claim 9, wherein the radial annular recesses are located along said pump pistons below the top surfaces of said pump pistons a distance corresponding to the distance between the top of said pump cylinders and the points where said inlet channels are introduced into said pump cylinders, whereby upon movement approaching extreme discharging positions of said pump pistons, said inlet channels are connected with the upper working space and said outlet channels by means of said radial and axial channels in said pump pistons.

11. A twin-pump for generating alternating pressures, out of phase by in two hydraulic systems, comprising an enclosure member having a pair of identical cavities; a pair of pistons slidably mounted in said cavities for movement between two positions, biasing means for urging said pistons into retracted positions; outlet channels connecting the tops of said cavities to said hydraulic systems; a reservoir; inlet channels connecting said cavities to said reservoir, said inlet channels being opened into said cavities at points above said tops of said retracted pistons, said pistons also havingannular recesses at points on said pistons so that said recesses communicate with said inlet channels in the piston extended positions, the pistons further having radial channels which open into said annular recesses, and axial channels which connect said radial channels with the tops of said pistons and the outlet channels whereby fluid communication is obtained between said outlet channels and said reservoir in piston extended positions; and cam driving means for moving said pistons, out of phase with one another, to urge said pistons into extended positions.

Claims

1. A hydraulic drive, particularly for weft insertion in weaving looms, comprising a component movable in a predetermined path between two positions; a pair of hydraulic units respectively located at opposite ends of said path and each comprising a cylinder and normally retracted piston means movable in the direction towards the other unit for movement of said component in said path; pump means comprising two independent pumps for respectively supplying liquid under pressure to said cylinders; and drive means for driving said two pumps out of phase with each other to thereby alternatingly moving said piston means of one unit towards the other unit so as to move said component between said positions thereof.

3. A hydraulic drive, particularly for weft insertion in a weaving loom, comprising a component movable in a predetermined path between two positions; a pair of hydraulic units respectively located at opposite ends of said path and each comprising a cylinder and normally retracted piston means movable in the direction towards the other unit for movement of said component in said path; pump means comprising two independent pumps respectively connected to said cylinders of the unit for alternatingly supplying liquid under pressure into the respective cylinder to move the associated piston means toward the other unit and thereby said cOmponent between the positions thereof, each of said pumps comprising a pump cylinder, a normally retracted pump piston movable in said cylinder between two positions one of which is a fully retracted position in the charging stroke of said pump and the other of which is a fully extended position in the discharging stroke of said pump; power means for moving said pump pistons in the respective pump cylinders in 180* out of phase relationship with respect to each other; and a pair of pump pipe lines respectively connecting said pumps to said hydraulic units.

4. A hydraulic drive as in claim 3, wherein said component is a weft inserter in a weaving loom and wherein said power means consists of a pair of cams, mounted on a rotating weaving loom shaft, the cams being rotated and rigidly mounted on said shaft so as to be displaced by 180* relative to one another, and lifting means supporting said pump pistons and riding on said cams in the respective pump for following said cams and lifting said pump pistons from their retracted positions.

5. A hydraulic drive as in claim 4, wherein each pump piston completes a charging and a discharging stroke for each 360* revolution of said loom shaft.

6. A hydraulic drive as in claim 4, wherein said loom shaft completes a 360* revolution for each operating cycle of the weaving loom.

11. A twin-pump for generating alternating pressures, out of phase by 180*, in two hydraulic systems, comprising an enclosure member having a pair of identical cavities; a pair of pistons slidably mounted in said cavities for movement between two positions; biasing means for urging said pistons into retracted positions; outlet channels connecting the tops of said cavities to said hydraulic systems; a reservoir; inlet channels connecting said cavities to said reservoir, said inlet channels being opened into said cavities at points above said tops of said retracted pistons, said pistons also having annular recesses at points on said pistons so that said recesses communicate with said inlet channels in the piston extended positions, the pistons further having radial channels which open into said annular recesses, and axial channels which connect said radial channels with the tops of said pistons and the outlet channels whereby fluid communication is obtained Between said outlet channels and said reservoir in piston extended positions; and cam driving means for moving said pistons, out of phase with one another, to urge said pistons into extended positions.