EP3512991B1

EP3512991B1 - Weft gripping mechanism for shuttleles weaving machines

Info

Publication number: EP3512991B1
Application number: EP17850359.5A
Authority: EP
Inventors: Sanjay KURKUTE
Original assignee: Individual
Current assignee: Individual
Priority date: 2016-09-14
Filing date: 2017-02-17
Publication date: 2024-01-17
Anticipated expiration: 2037-02-17
Also published as: CN109844197B; EP3512991A1; WO2018051193A1; EP3512991A4; CN109844197A; EP3512991C0

Description

The following specification particularly describes and ascertains the nature of this inventions and manner in which it is to be performed.

DESCRIPTION:

A. TECHNICAL FIELD OF INVENTION :

Present invention relates to textile engineering field and more particularly to the arrangements for tensioning of weft on shuttle less weaving machines. For many decades, catch selvedges or false selvedges are the only resort available for this purpose on shuttle-less weaving machines.
The invention refers to a Weft Gripping mechanism for use on rapier type shuttle-less weaving machines. There is no such or similar device in existence today and the need for such a mechanism arises from the key points disadvantages of existing systems explained below further.

B. PRIOR ART:

Conventionally Catch or False selvedge former, which is a set of selvedge threads which are used to grip the weft yarn. The action is performed just like normal shedding of threads but the only changes which exist are in timing. Catch Selvedge Warp threads are timed to close their shed earlier than body warp and their action too is faster because of short time available to grip the exiting weft insertion media before it relieves the weft from its grip. And because the weft is CAUGHT by the selvedge warp threads, the tension in the weft threads inserted is maintained in such type of set ups. But this mechanism has some serious disadvantages as follows.
DE 90 15 788 U1 discloses a device on weaving machines, which serves to actuate working elements arranged on the sley for the weft thread insertion. The actuating device is preferably used on non-shuttle weaving machines whose weft insertion is carried out with bar or band rapiers. This device is intended to clamp the weft between the weft scissors and the supply bobbins in order to avoid the weft thread falling off.
Also, it is known form prior art US 4 834 147 relating to a weft thread cutting mechanism in a shuttleless loom performs an excess stroke to bring the scissors mechanism, which is combined with a clamping mechanism, as close to the weft thread insertion gripper as possible in order to reduce weft thread waste. For this purpose, the fixed scissors blade is tiltable between a working position and a rest position in a plane extending substantially perpendicularly to the weft thread insertion direction.
Whenever a weft thread is inserted in shed formation, it is always in the form of a single separate thread cut to a certain length. And both the ends of weft, therefore, need to be secured by some means before the insertion mechanism leaves it after which it is cut to length. This securing function is known to be performed by selvedge former which is usually called as FALSE SELVEDGE.

1. Conventionally, the timing of false selvedge is normally kept early and some rubbing occurs between the selvedge warp threads and the gripper and it is observed that, out of total machine stoppages as a result of warp thread breakage, the majority of breakages are from this selvedge area because of this rubbing action which cannot be avoided in conventional set ups. With the advent of this path breaking Weft Gripping mechanism, rubbing action is totally eliminated and so will be the breakages due to rubbing. It also improves the gripping force exerted on the weft thread and brings about a better tension control of the weft thread, which is known to be the key element for a better fabric appearance.
2. Because the timing of conventional false selvedge is not so precise, excessive wastage of weft yarn occurs as the protruding length of weft thread has to be kept to a higher side. Unlike this, the new weft grip mechanism allows a more precision setting of weft grip, which in turn means exact or optimum weft protruding length, which obviously means lesser wastage of weft yarns. This saving can be a reduction of wastage from 4% to 3% with this device. Although this 1% appears very small, when calculated as a cost of 1% weight of total weft yarn consumed per year, this figures becomes a huge amount of saving. Moreover, 1% reduction in 4% waste is a whopping 25% reduction in waste by its weight. This will surely have a huge commercial significance and impact and a major achievement of this path breaking device.
3. The selvedge has to be timed a bit early in order that the insertion mechanism leaves the weft thread after it comes out of the shed and weft must be gripped at this precise moment, the crossing of warp selvedge threads is not one of the precise actions and to find a timing when the warp will grip the weft is too difficult to spot physically on the weaving machine, this makes the timing sequence itself a bit ambiguous and full of compromises. The new Weft Grip Mechanism will eliminate this ambiguity of timing altogether.
4. As mentioned above, the rubbing action of selvedge warp and weft insertion gripper makes the whole idea of this type of gripping vulnerable by dangers of thread breakage and machine stoppages point of view. Any saving in this breakage instances means improvement in the machine efficiency and saving losses arising out of down time in the event of thread breakages, this also has a quality significance as each start and stop on a weaving machine can result in fabric defects known as start/stop marks. The new Weft Grip Mechanism will thus improve efficiency as well as the quality of cloth produced on the machine.

D. OBJECTIVES OF THE INVENTION :

1. Where in the main objective of the invention is to grip the weft thread by purely mechanical means, and unlike conventional false selvedges, before it is cut to length on a shuttle less weaving machine.
2. Wherein the supplementary objective of the invention is to art a weft gripping mechanism, the action timing of which will be easy and precise to set and thus exercise control over the weft yarn wastage by establishing a precise control over the protruding length of weft beyond the grip.
3. Wherein the another additional objective of the invention is to art a weft gripping mechanism wherein the force exerted on weft thread, upon grip, can be precisely set according to the weft yarn variety, so as to achieve a better fabric appearance.
4. Wherein another additional objective of the invention is that the weft grip mechanism is an additional device on the weaving machine, thus it should be very compact and should not hinder with the existing mechanisms on the weaving machine.

E. BRIEF DESCRIPTION OF DRAWINGS:

The invention will now be described with the help of a drawing accompanying this specification wherein salient features have been shown by suitable numerals and referred to appropriately in the following description.

Patent Illustration comprises 7 Diagrams:

Description on Patent Illustration Diagram 1: Weft Grip Mechanism, Exploded view (left), Assembled but Cover Removed View (Right)

The body (1) of weft Grip Mechanism which is mounted securely on a part (numbered 16 and explained further) which is mounted directly on the sley bracket of the weaving machine in such a way that it can be moved sideways at desired position relative to the selvedge of the fabric being woven and can be locked in that place for operation. This is better explained in detail in Description of Patent Illustration 2 below. The body (1) has following details built in, hole (1A) is provided in weft grip mechanism body (1) for shaft (8), a Projection (1B) is provided on the body (1) for arresting plate cam (2) and allowing a sideways motion to the plate cam (2), a small space (1C) for slider part (3) is provided on body (1). A Suitable number of holes (1D) are provided in the body so that mounting fasteners (12) of the Cover (7) as explained further.
Further, Plate Cam (2) has following details built in to it. A Locking place (2A) is provided for slider part (3), a step (2B) is provided for mating with body (1) at (1B), two cam slots (2C) are provided for guiding and moving the pins (4B and 5B), these pins (4B and 5B) are either integrally built or assembled on weft grip levers (4 and 5) explained further.
Slider part (3) which gets affixed to the shaft 8 and has following details built on to it. 3A is hole through which shaft 8 passes and gets fitted, 3B is a cross hole through which a part 9 passes through in order to fix the slider 3 to shaft 8.
The Weft Grip lever Lower (4) which has following details built in to it, A central cylinder portion (4A) which is a pivot for movement of this lever, a cylindrical projection (4C) provided on the motion input lever (4B) to mate with cam slots (2C), and a grip arm (4D) is provided which helps gripping the weft thread in conjunction with Weft Grip Lever upper (5) described further.
The Weft Grip lever Upper (5), which has following details built in to it, A central cylinder portion (5A) which is a pivot for movement of this lever, a cylindrical projection (5C) re provided on the motion input lever (5B) to mate with cam slots (2C), and a grip arm (5D) is provided which helps gripping the weft thread in conjunction with Weft Grip Lever lower (4) described earlier.
Bearing cap (6) for Weft Grip Levers (4 and 5) is devised and intended to clamp the cylindrical portion (4A and 5A)

Cover (7) of the weft grip mechanism is devised to enclose all moving parts inside it, together with the projection (1B) described above it provides a sliding guide to the cam(2)
Sliding shaft (8) is intended to impart motion to weft Grip actuation through slider part (3) described earlier
Slider Part (3) is affixed to the shaft (8) by a brass / copper sleeve (9)
A fastener (10) is provided for clamping sleeve (9), and fasteners (11) for bearing cap (6), fasteners (12) are provided for fastening the cover (7) on to Body (1), Fasteners (13) are for fixing the weft grip mechanism on the tee slot part at desired lateral position depending on fabric width.
WORKING : The body (1) of the weft grip mechanism is affixed by fasteners (13), shaft (8) passes through the hole in body (1) at (1A), in such a way that slider part (3) is engaged with the shaft (8), at hole in to slider (3) at (3A), and it remains in to a small recess (1C) in body (1). Slider (3) is affixed to shaft (8) by means of clamping sleeve (9) and a fastener (10). This way the slider part (9) moves in unison with shaft (8) but within the recess (1C). Weft Grip lower (4) and weft Gripp upper (5) are mounted on to body (1) as shown in figure by means of cap (6) and fasteners (11) in such a way that they can freely swing around their axes at (4A and 5A). Now the plate cam (2) sits on Body (1) in such a way that face (2B) is butted with lower surface of Projection (1B) and Pins (4B and 5B) engage with slots (2C) in the plate cam (2), at the same time plate cam is also mounted in such a way that the notch (2A) engages with the slider part (9) and motion of the shaft(8) is thus transferred to the plate cam (2). The to and fro motion of shaft (8), thus gets transferred to slider part (9), then to Plate cam (2) and then to the Weft Grip lower and upper (4 and 5) through mechanical mate between slots (2C) and pins (4B and 5B). The weft grip can thus open and close based on position of the shaft(8) in a reliable manner.

Patent Illustration Diagram 2:

Overall arrangement for weft Grip Mechanism

This diagram shows an illustration of small section of sley on which a weft grip mechanism is mounted and it is shown as a small section for the sake of description simplicity, however sley will be much longer than what is shown and plurality of sley brackets are present on the machine. Sley Shaft (14) provides a mounting for several Sley shaft brackets (15) on which Tee slot part (16) mounted directly on sley brackets (15), the tee slot (16A) of the tee slot part (16) provides the mounting for entire Weft Grip mechanism by means of fasteners (13) in such a manner that it can be affixed to the tee slot in several lateral positions as per fabric width woven on the weaving machine. The Extruded Sley profile (17) is also mounted on the sley brackets (15). The tee slot part (16) has the small end bearing brackets (18) mounted on both sides of it which provide a sliding support to the shaft (8), another Intermediate support (19) is also provided for shaft (8) to reduce span length and to avoid buckling of shaft (8), this support(19) is also adjustable laterally based on working position of the weft grip mechanism on the tee slot part (16). Guide block and rapier tape guide assembly (20) along with Tape Guide plates (21) for rapier and, weaving reed (22) is also mounted on the sley profile (17). The weft grip mechanism is so adjusted widthwise in such a manner that the upper and lower weft grip levers are in between two tape guide plates and are not fouling with the plates during opening and closing operation of the same.

Patent Illustration Diagram 3:

Side View of Weft Grip Mechanism Mounting on machine

The small end brackets for shaft (8) are clamped to tee slot part (16) by means of fasteners (16B), these were not visible in any of the earlier views. The diagram mainly shows Space for weft carrying media between weft grip lever lower (4) and weft grip lever upper (5) for passing of rapier head and tape through the opened weft grip levers, the view is aligned as if it is seen by the incoming rapier head.

Patent Illustration Diagram 4:

Top View of Weft Grip Mechanism - arrangement on the machine

The diagram shows overall view of the weft grip assembly as seen from the top of the weaving machine. the details of the two rectangles are shown in enlarged view for better understanding of the same at the bottom indicated by respective enlargement arrows. Shaft (8) carries a Clamping collar Stopper (23A), Clamping Collar (23B) for preloading and return spring (23C) arranged in such a manner that spring (23C) itself executes the return action on shaft (8) to keep it at normal pushed out condition. The force of spring (23C) is also the force used for gripping the weft. Stronger the spring better will be the gripping force on the weft yarn and vice versa, and this has to be set according to the type of yarn used, lighter spring for delicate yarns and stronger spring for coarser weft yarns. The diagram also elaborates placement of weft grip mechanism in such a manner that the weft grip levers are working between two adjacent tape guides (21).

Patent Illustration Diagram 5:

Weft Grip Drive and its Timing Setting Arrangement

This figure shows the driving arrangement of weft grip mechanism. Weft Grip Driving Surface Cam assembly is mounted on the machine frame/body and has a setting provision wherein the timing of the weft grip mechanism can be set in a angular advance or retard position relative to the machine. The surface cam (24) having a cam plate (24A) and a cylindrical projection (24B) is clamped by a Clamping and setting disk (25) which is diametrically locked and axially free to move on the surface cam cylindrical projection (24B) which is on the other side of the machine frame / body in such a manner that fastening of the screws will sandwich the machine frame between the surface cam body (24A) and clamping Disk (25). The diametrical lock between Cam Cylindrical projection (24B) and Clamping disk (25) is essential because rotating this disk should also apply equal rotation to the cam. There are several radial holes (25A) on periphery of clamping disk for facilitating setting movement. Swing Lever (26) has a projection (26A) for connection with the connecting rod (31) and an Axial driving shaft (27) passes through the swing lever (26) and is diametrically locked with the swing lever but it is free to slide along its axis and the shaft is spring loaded to remain pressed against the surface cam (24A). Axial drive shaft (27) for weft grip mechanism bears a Cam follower mounting clamp (28), provides a seating for return spring (29 ), stopper (30) with a spring mounting disk is fitted on on shaft (27), further connecting rod (31 ) for Swing link (26) gets motion for the swing shaft through connecting rod having big end (31A) and connecting rod small end (31B), the big end of which is mounted on eccentric cam (32) which is in turn mounted on a machine shaft (33) is running at weaving cycle speed.
WORKING : The connecting rod (31) mounted on the eccentric (32) brings an oscillating motion to the swing lever (26) and the same is transferred to the shaft (27) as this shaft is diametrically locked with swing lever (26). The cam plate (24A) has a cam projection which is better seen and explained in diagram 6 below, this projection causes the follower (28A) to get pressed backward or forward as it follows the cam surface, pre load of the spring (29) keeps the shaft forcefully pressed on the cam and thus it also drives / presses the shaft (8) depending upon its position on the surface cam. The timing, as said earlier is set by means of rotating and clamping the cam along with the setting and clamping disk and locking of fasteners (25B).

Patent Illustration Diagram 6:

Weft Grip and its drive at open and closed positions

Refer to diagram A) Weft Grip of Closed (Gripped) position and/or just before opening position, unless opened by the driving mechanism, the weft grip remains in closed or gripped position, at this position the lever (26A) remains rotated at lower most position as shown by rotary arrow around label 26A, thus follower (28A) remains riding on the cam projection and pressed back towards the activation spring (29), shaft (27) remains retracted behind and thus shaft (8) is at free position, the weft Grip is at closed position.
Refer to diagram B) Weft Grip of Opened position or during weft insertion phase, this is activated position of the mechanism and activation means opening of weft grip, at this position the lever (26A) remains rotated to uppermost most position as shown by rotary arrow around label 26A, thus follower (28A) is released from the cam projection and gets pressed forward by the activation spring (29), shaft (27) comes out as a result and thus shaft (8) is also pressed towards the open position, the weft Grip is also at position, allowing the passage of the weft gripper through.
The closed position remains intact during the beat up operation. As soon as the sley comes back to backward most position or the position where rapier heads move inside the shed formation, but before the rapiers move in, the weft grip mechanism is driven to open position, and as soon as the rapiers exit the shed after transfer of thread, the weft grip is timed to close, coinciding with the gripper opening block timing.

Patent Illustration Diagram 7:

Alternative Embodiments

The alternative embodiments. The weft grip described in above primary embodiment and best mode of this invention, is on two axes of upper and lower weft grip levers. However an alternative embodiment should also be described where in the two axes of the two weft grip upper and lower levers coincide with each other by a hollow shaft in shaft arrangement as shown in diagram 7.
Another alternative embodiment of this mechanism is in the driving mechanism, wherein the connecting rod connection between the swing lever, connecting rod and the shaft can be replaced by a rack and pinion arrangement where in the shaft shall bear the pinion gear and the connecting rod will be replaced by the rack gear oscillating to and fro path imparting a rotary swing motion to the shaft in order to move the follower bearing over the surface cam in the same fashion.
From the descriptions of the diagrams above, it is clearly established that all main as well as secondary objectives of the invention are clearly achieved.

NOMENCLATURE

The nomenclature relates to 7 Patent Illustration diagrams enclosed with this.

Patent Illustration Diagram 1: Weft Grip Mechanism, Exploded view (left), Assembled but Cover Removed View (Right)

1 is body of weft Grip Mechanism,
- 1A is hole for shaft 8,
- 1B is Projection for arresting plate cam,
- 1C is space for slider part 3
- 1D are mounting holes for cover 7
2 is Plate Cam,
- 2A is Locking place for slider part 3,
- 2B is step for mating with body 1 at 1B,
- 2C is cam slots for guiding pins 4B and 5B
3 is slider part
- 3A is hole for shaft 8
- 3B is cross hole for clamping part 9
4 is Weft Grip lever lower,
- 4A is central cylinder portion or pivot,
- 4B is motion input lever
- 4C is cylindrical projections to mate with cam slots 2C
- 4D is grip arm
5 is Weft Grip lever upper,
- 5A is central cylinder portion or pivot,
- 5B is motion input lever
- 5C is cylindrical projection to mate with cam slots 2C
- 5D is grip arm
6 is Bearing cap for Weft Grip Levers 4 and 5
7 is cover of weft grip mechanism
8 is sliding shaft of weft Grip actuation
9 is brass / copper sleeve for clamping part 3 to shaft 8
10 is fastener for sleeve 9
11 are fasteners for bearing cap 6
12 are fasteners for cover 7