WO2005098111A1

WO2005098111A1 - Water jet loom as well as a plunger pump for use in a water jet loom

Info

Publication number: WO2005098111A1
Application number: PCT/NL2005/000215
Authority: WO
Inventors: Gerard Cox
Original assignee: Te Strake Textile B.V.
Priority date: 2004-04-07
Filing date: 2005-03-22
Publication date: 2005-10-20
Also published as: NL1025893C2

Abstract

The invention relates to a water jet loom (1) comprising means (11) for forming a shed (13) of warp yarns (12), with inserting means (14, 16) being disposed on one side or on both sides of the shed (13) for inserting one or several different weft yarns (15) into the shed (13) by means of a pulsed water jet, which inserting means are made up of: a plunger pump (20) comprising a plunger housing (22) having a plunger chamber, which can hold an amount of water required for every weft yarn, as well as a plunger (23) that is movable within the plunger chamber (22) under the influence of a pre-tensionable plunger spring element that is accommodated in the housing. The invention also relates to a plunger pump for use in a water jet loom. The object of the invention is to provide a water jet loom and a plunger pump as referred to in the introduction, which enable a quick and especially automatic adjustment of the plunger pump to the type of weft yarn. According to the invention, the water jet loom comprises comparing means (34) arranged for comparing a detected time of arrival of the weft yarn at a particular position in the shed with a desired time of arrival and for delivering a signal in case a difference is detected between the two times, as well as adjusting means arranged for adjusting the pulsed water jet as delivered by the inserting means on the basis of said signal.

Description

Water jet loom as well as a plunger pump for use in a water jet loom.

DESCRIPTION The invention relates to a water jet loom comprising means for forming a shed of warp yarns, with inserting means being disposed on one side or on both sides of the shed for inserting one or several different weft yarns into the shed by means of a pulsed water jet, which inserting means are made up of: a plunger pump comprising a plunger housing including a plunger chamber, which can hold an amount of water required for every weft yarn, as well as a plunger that is movable within the plunger chamber under the influence of a pre-tensionable plunger spring element that is accommodated in the housing. The invention also relates to a plunger pump for use in a water jet loom. Water jet looms are generally known and are described in, for example, US Patent No. 4,121,626. In a water jet loom, a weft yarn is inserted or "shot" into the shed each time by means of a pulsed water jet delivered by a plunger pump. The weft yarn has a length that corresponds to the length of the shed. It is desirable, therefore, for the weft yarn to be precisely inserted into the shed with every "shot", with the beginning of the weft yarn being positioned at or just beyond the end of the shed. If the plunger pump is not correctly controlled, weaving faults will result, with every weft yarn being stopped too soon or too late in the shed. To that end, the position of the weft yarn in the shed, more particularly at the end of the shed, of a water jet loom is determined, usually by manual means. Then the water jet loom, and in particular the pulsed water jet as delivered by the plunger pump, is set manually on the basis of said measurement data. Adjusting a water jet loom manually by "trial and error" is a fairly labourious and complex process, which problem is even aggravated when the water jet loom is to process several different weft yarns (for example differing in colour, thickness, composition, etc). Each type of weft yarn requires a different setting of the plunger pump and it is also for this reason that several plunger plums are used in the water jet loom. The manual setting and adjusting of the known the water jet looms thus becomes even more complex and time-consuming. The object of the invention is to provide a water jet loom and a plunger pump as referred to in the introduction which do not exhibit the above drawbacks and which enable a quick and especially automatic adjustment of the plunger pump to the type of weft yarn. According to the invention, the water jet loom comprises comparing means arranged for comparing a detected time of arrival of the weft yarn at a particular position in the shed with a desired time of arrival and for delivering a signal in case a difference is detected between the two times, as well as adjusting means arranged for adjusting the pulsed water jet as delivered by the inserting means on the basis of said signal . As a result it is no longer necessary to set or adjust the water jet loom by "trial and error". The automatic feedback of differences in the arrival times of the various weft yarns to the inserting means and the adjustment of the water jet loom by adjusting means make it possible to obtain a correct weaving result. Furthermore a more efficient operation and a simpler construction of the water jet loom can be obtained in this manner, because only one plunger pump will suffice for processing several, different types of weft yarns (differing in colour, thickness, composition, etc). A fully automatic adjustment of the water jet loom and the plunger pump can be obtained in that, according to a functional embodiment, the water jet loom is provided with time determining means for detecting at least the time of arrival of the weft yarn at a particular position in the shed. In a specific embodiment, the adjusting means are arranged for adjusting the length of stroke of the plunger. In another embodiment, in which the plunger is connected to a plunger lever, which plunger lever can be pivoted about a pivot point by means of a rotary cam follower for pre-tensioning the plunger spring element and determining the length of stroke of the plunger, the adjusting means are arranged for influencing the pivoting movement of the plunger lever. With this aspect, the adjusting means may comprise a stop surface to be moved into contact with the plunger lever, which stop surface may vary in height. On the other hand, the stop surface may be built up of several, mutually different stops. To enable a quick and functional adjustment of the length of stroke of the plunger pump in dependence on the differences in the insertion of successive weft yarns or a changeover to another type of weft yarn, the stop surface is provided on a rotary disc. The stops may be arranged in a circle on said rotary disc. The above aspects of the stop surface according to the invention make it possible to realise a very quick and automatic changeover of the water jet loom and in particular the plunger pump during operation, for example to another type of weft yarn, or an adjustment thereof in response to detected differences in the arrival times or the velocity of the weft yarns. To prevent damage or irreparable deformation caused by the repeated striking of the plunger lever against the stop surface, the rotary disc is according to the invention provided with cuts extending on either side of each stop. As a result, each stop forms a slightly springing element, which absorbs the initial impact of the plunger lever. In another functional embodiment according to the invention, the adjusting means are arranged for adjusting the position of the pivot point of the plunger lever with respect to the plunger pump. The adjusting means used in said embodiment comprise an extension element that can be actuated, which extension element engages the pivot point of the plunger lever. More specifically, the extension element is in the form of a spindle. In yet another embodiment according to the invention, the adjusting means are arranged for adjusting the pre-tension of the plunger spring element. The adjusting means used in sa d embodiment may comprise a drivable transmission, which transmission engages a plunger spring element adjusting screw that forms part of the plunger housing. More in particular, the transmission is a gear transmission made up of a drivable gear and teeth present on the plunger spring element adjusting screw. The invention will now be explained in more detail with reference to a drawing, in which: Figure 1 shows a water jet storm according to the prior art; Figure 2 shows a plunger pump for use in a water jet loom according to the prior art; Figures 3A-3C show different embodiments of a water jet loom according to the invention; Figure 4 shows a first embodiment of a plunger pump according to the invention; Figures 5a-5d show further aspects of the embodiment of a plunger pump according to the invention as shown in Figure 4; Figure 6 shows a second embodiment of a plunger pump according to the invention; Figure 7 shows a third embodiment of a plunger pump according to the invention. For a better understanding of the invention, like parts will be indicated by the same numerals in the description of the figures below. Figure 1 shows a water jet loom according to the prior art. The water jet loom 10 comprises means 11 for forming a shed 13 of warp yarns 12. Inserting means 14, 16 are disposed on one side of the shed 13 for inserting one or more, whether or not different, weft yarns 15 into the shed 13 by means of a pulsed water jet. The weft yarn 15 is pulled off a bobbin 17 by a pre-unwinding device 16, which winds the length of the weft yarns 15 that is required for each weft in one or more windings onto a winding body. The inserting means 14 thus will pull the length of weft yarn required for each weft from the winding body of the pre-unwinding device 16 in one go. To insert or "shoot" the successive weft yarns 15 into the shed, a water jet loom 10 according to the prior art makes use of a pulsed water jet that is squirted or shot into the shed 13 via a nozzle 14 (which forms part of the inserting means), "dragging along" the weft yarn 15. To pressurise and deliver a brief pulsed water jet via the nozzle 14, said nozzle is connected to a plunger pump 20 via a water pipe 21a-21b. The housing 22 of the plunger pump 20 forms a plunger chamber (not shown), in which a plunger 23 is movable. The plunger 23 is movable within the plunger chamber under the influence of a pre- tensionable the plunger spring (not shown, either). The plunger 23 can be moved reciprocatingly by means of a rotary cam follower 25 via a plunger lever 24, which pivots about a pivot point 24a, for delivering a pulsed water jet with each inward stroke. The weft yarn 15 being inserted with each inward stroke is cut off by cutting means 18 on either side of the shed 13, and the end product 19 thus woven is rolled up for further processing. Figure 2 shows a plunger pump 20 according to the prior art as currently used in the water jet loom 10 that is shown in Figure 1. A cylindrical part 26 forming a plunger chamber 31 is present in the plunger housing 22. The plunger 23 is accommodated in the plunger chamber 31 for reciprocating motion therein. The inward stroke of the plunger 23 (from the right to the left in Figure 2) takes place under the influence of a plunger spring element (a plunger spring in this embodiment) 27, which is accommodated in the plunger housing 22, surrounding the plunger 23. The reciprocating motion of the plunger 23 is effected by a plunger lever 24, which is connected with one end 24c to the part 23a of the plunger 23 that projects from the plunger chamber 31 and that bears against a rotary cam follower 25 with another lever end 24b. The known plunger lever 24 pivots about a fixed pivot point 24a. Rotation of the cam follower 25 will impose an outward stroke on the plunger 23 via the lever 24, thereby pre-tensioning the plunger spring 27 in the plunger housing 22-28. As a result, the plunger chamber 31 is filled with a certain amount of water via the inlet side 21a of the water pipe 21. To enable this, the one-way ball valve 30a opens, whilst the one-way ball valve 30b in the outlet side 21b of the pipe 21 remains closed. The moment the lever 24 is "released" by further rotation of the cam follower 25, the plunger 23 will carry out an inward stroke under the i fluence of the pre-tension to plunger spring 27, thereby driving the amount of water that is present in the plunger chamber 31 into the pipe portion 21b towards the nozzle 14 (Figure 1) with great force via the one-way ball valve 30b. The ball valve 30a is closed during the outward stroke. The characteristics of the pulsed water jet which is delivered as a result of the reciprocating motion of the plunger 23 and which is utilized via the nozzle 24 for "shooting" the weft yarn 15 into the shed is largely determined by the pre-tension of the plunger spring 27 on the one hand and by the length of stroke of the plunger 23 in the plunger chamber 31 on the other hand. With the plunger pumps that are currently known, the tension of the plunger spring 27 can be set by means of the plunger spring adjusting screw 28, which mates with screw thread 22a of the plunger housing 22 via screw thread 28a. Adjustment of the pre-tension of the plunger spring 27 and thus of the pressure of the water pulse being delivered with each reciprocating stroke can be effected by tightening or loosening the plunger spring adjusting screw 28. The amount of water that is delivered from the plunger chamber 31 is largely determined by the amount of travel of the plunger 23 during the inward stroke (from the right to the left in Figure 2), which amount can be adjusted by means of a stop 29 in the form of an adjustable screw or bolt, by which the maximum amount of travel of the lever end 24c after being released by the cam follower 25 can be adjusted. When the water jet loom 10 as shown in Figures 1 and 2 is normally operated, the weft yarn 15 in question is preferably positioned between the warp yarns 12 across the entire width of the shed 13 with every "shot". It is undesirable if the weft yarn 15 stops too soon or too late in the shed 13, since such deviations not only have an adverse effect on the efficiency of the loom, but eventually they will inevitably lead to weaving faults and thus to the woven product being rejected. To ensure that the weft yarn 15 is positioned between the warp yarns 12 across the entire width of the shed 13 with every shot, it is (manually) verified whether the beginning of each weft yarn 15 is correctly positioned in the shed 13. If any deviations are detected, the water jet loom must be stopped for a short period of time and the plunger pump 20 must be (re)adjusted. This means that the pre-tension of the plunger spring 27 must be changed manually by turning the plunger spring adjusting screw 28 accordingly with respect to the plunger housing 22. On the other hand, it is also possible to adjust the stop by rotating the bolt 29 so as to adjust the length of the inward stroke of the plunger 23. The setting or adjusting of a prior art water jet loom 10 according to this "trial and error" principle is a labourious process, which affects the efficiency of the loom. Said setting or adjusting of a prior art water jet loom 10 becomes even considerably more complex if the water jet loom 10 makes use of di fferent types of weft yarns 15, which differ from each other as regards their colour, their thickness or their composition. A separate plunger pump must be used for each different type of weft yarn, which pumps need to be adjusted specifically for the yarn in question. A changeover of the water jet loom 10 to another type of weft yarn makes it necessary to readjust the plunger pump in question, therefore. As nowadays weaving products 19 comprising a large number of different weft yarns (different as regards their colour, thickness and/or composition), it will be understood that adjusting the water jet loom in question only becomes more complex. According to the invention (Figure 3A) , the water jet loom 10 according to the invention comprises time determining means 32 for detecting at least the time of arrival of the weft yarn 15 at a particular position in the shed. The measuring position is located at the end of the shed 13 in the embodiment according to Figure 3A, whereas in the embodiment according to Figure 3B the time determining means 32 and the measuring position are located at the beginning of the shed 13. Figure 3C shows yet another embodiment, in which the time determining means 32 are placed on or near the inserting means 16 and thus measure and consequently measure at the location where the weft yarn is delivered to the shed by the inserting means. The water jet loom according to the invention (and as shown in Figures 3A-3C) also comprises comparing means 34 for comparing the detected time of arrival with a desired time of arrival and for delivering a signal to the inserting means 16, 14-20 in case a difference between the two times is detected. The water jet loom also comprises adjusting means (not shown in Figures 3A-3C) arranged for adjusting the pulsed water jet delivered by the inserting means, and more particularly by the plunger pump 20, on the basis of the signal delivered by the comparing means 34. In this way the water jet loom 10 can be automatically (re)adjusted in a simple manner during full operation in case differences should be detected during the insertion of successive weft yarns into the shed 13. In Figure 3C the comparing means 34 are arranged for delivering different signals to the various inserting means 16, 17-20 (intended for different types of weft yarns and indicated by the numerals "1", "2", "3", etc. in subscript) in case a difference is detected between the two times. This makes the water jet loom universally applicable, since different types of weft yarns can now be processed in a quick and efficient manner. A first embodiment of the water jet loom 10 and the plunger pump 20 according to the invention is shown in Figure 4. In Figure 4, the adjusting means are indicated at 40, being arranged in this embodiment for adjusting the length of the inward stroke of the plunger 23. More particularly, the adjusting means 40 influence the amount of travel of the pivoting plunger lever 24, since the adjusting means 40 form a stop surface 44 that can be brought into contact with the plunger lever 24. In the embodiment of Figure 4, the adjusting means 40 comprise a disc 41 which is mounted on a rotary shaft 42 that can be rotated by a drive motor 43. Several stops 44 are present on the disc 41, which stops are different from each other as regards their height. Thus, a specific stop 44 having a specific height can be positioned in front of the lever end 24c through rotation of the disc 41 by the motor 43 on the basis of the setting signal delivered by the comparing means 34. This makes it possible to adust the maximum amount of travel of the plunger lever 24 and thus the length of stroke of the plunger 23. The embodiment of the adjust ng means 40 is shown in more detail in Figure 5A. In another embodiment as shown in Figure 5B, the stop surface on the disc 41 is not made up several stops of varying height 44, but it is configured as a continuous, sloping stop surface 44'. Suitable rotation of the disc 41 by the motor 43 will position a stop surface 44 of a particular height just in front of the lever end 24c, thus reducing/adjusting the maximum lergth of (the inward) stroke of the plunger 23. As Figure 5C shows, the various stops 44 are arranged in the form of a circle on the rotary disc in the embodiments of the adjusting means 40 that are shown in Figures 4 and 5A. In another embodiment, which is shown in Figure 5B, the rotary disc 41' ' is provided with several radially extending cuts 45, which are formed in the disc 41' ' on either side of each stop 44. Each stop 44 thus forms a slightly springing element, which has a slightly absorbing effect as regards the repeated impact of the plunger lever 24c on the stop 44. As a result, the load on -the disc 41, the shaft 42 and the motor 43 is considerably reduced, resulting in a prolonged life span thereof. In another embodiment as shown in Figure 6, the adjusting means are indicated at 50. The adjusting means 50 are arranged for moving the pivot point 24a of the plunger lever 24 with respect to the cam follower 25 and the plunger pump 20. The adjusting means 50 comprise an extension element 51, in this case in the form of a spindle, which can be extended or retracted by means of a drive motor 53 and a screw guide 55 connected to the fixed construction 54. The spindle 51 engages the plunger lever 24 near its pivot point 24 wi h a supporting surface 52. As indicated in the dotted lines, the pivot point 24a will be moved downwards (in Figures 6) upon extension of the spindle 51 by the motor 53, causing the length of stroke of the plunger 23 to decrease. As a result, the amount of water being forced -From the plunger chamber 31 through the ball valve 30b into the pipe portion 21b with every inward stroke is reduced. Another embodiment of the adjusting means is indicated at 60 in Figure 7. In Figure 7, the adjusting means 60 are arranged for adjusting the pre-tension of the plunger spr ng 27. The adjusting means 60 comprise a drive motor 63, which rotates a shaft 62. A gear 61 is mounted on the shaft 62, which gear comprises external teeth 61a that mate with external teeth 28b mounted on the plunger spring adjusting screw 28. The difference signal delivered by the comparing means 34 functions as a control signal for the drive motor 63, which rotates the gear 61 on the basis thereof, thus adjusting the tension of the plunger spring 27 by means of the plunger spring adjusting screw 28. It will be apparent that the water jet loom 10 and the plunger pump 20 according to the invention provide a fully automatically operated water jet loom, which plunger pump 20 can be quickly adjusted during operation when differences are detected or when the water jet loom 10 is to be changed over to another type of weft yarn. The water jet loom according to the invention makes it possible to realise a more efficient operation whilst using a simpler construction, because only one plunger pump is needed, by means of which a large number of different types of weft yarns, which are different from each other as regards their composition, their colour and their thickness, can be processed.

Claims

1. A water jet loom comprising means for forming a shed of warp yarns, with inserting means being disposed on one side or on both sides of the shed for inserting one or several different weft yarns into the shed by means of a pulsed water jet, which inserting means are made up of: a plunger pump comprising a plunger housing including a plunger chamber, which can hold an amount of water required for every weft yarn, as well as a plunger that is movable within the plunger chamber under the influence of a pre-tensionable plunger spring element that is accommodated in the housing, characterized in that the water jet loom comprises comparing means arranged for comparing a detected time of arrival of the weft yarn at a particular position in the shed with a desired time of arrival and for delivering a signal in case a difference is detected between the two times, as well as adjusting means arranged for adjusting the pulsed water jet as delivered by the inserting means on the basis of said signal.

2. A water jet loom according to claim 1, characterized in that the water jet loom is provided with time determining means for detecting at least the time of arrival of the weft yarn at a particular position in the shed.

3. A water jet loom according to claim 1 or 2, characterized in that the adjusting means are arranged for adjusting the length of stroke of the plunger.

4. A water jet loom according to claim 3, in which the plunger is connected to a plunger lever, which plunger lever can be pivoted about a pivot point by means of a rotating cam follower for pre-tensioning the plunger spring element and determining the length of stroke of the plunger, characterized in that the adjusting means are arranged for influencing the pivoting movement of the plunger lever.

5. A water jet loom accordi ng to claim 3 or 4, characterized in that the adjusting means comprise a stop surface to be moved into contact with the plunger lever.

6. A water jet loom according to claim 5, characterized in that said stop surface varies in height .

7. A water jet loom according to any one or more of the claims 4-6, characterized in that the stop surface is built up of several, mutually different stops.

8. A water jet loom according to any one or more of the claims 4-7, characterized in that the stop surface is provided on a rotary disc.

9. A water jet loom according to claim 8, characterized in that the stops are arranged in a circle on said rotary disc.

10. A water jet loom according to claim 9, characterized in that the rotary disc is according to the invention provided with cuts extending on either side of each stop.

11. A water jet loom according to any one or more of the preceding claims, characterized in that the adjusting means adjust the position of the pivot point of the plunger lever with respect to the plunger pump.

12. A water jet loom according to claim 11, characterized in that the adjusting means comprise an extension element that can be actuated, which extension element engages the pivot point of the plunger lever.

13. A water jet loom according to claim 12, characterized in that said extension element is in the form of a spindle.

14. A water jet loom according to claim 1, characterized in that the adjusting means are arranged for adjusting the pre-tension of the plunger spring element.

15. A water jet loom according to claim 14, characterized in that the adjusting means comprise a drivable transmission, which transmission engages a plunger spring element adjusting screw that forms part of the plunger housing.

16. A water jet loom according to claim 15, characterized in that the transmission is a gear transmission made up of a drivable gear and teeth present on the plunger spring element adjusting screw.

17. A plunger pump for use in a water jet loom, comprising a plunger housing including a plunger chamber, which can hold an amount of water required for every weft yarn, as well as a plunger, which is movable within the plunger chamber under the influence of a pre- tensionable plunger spring element that is accommodated in the housing, as defined in any one or more of the preceding claims.