WO2021214615A1

WO2021214615A1 - An apparatus and a method for changeover of unwinding rolls of fabric

Info

Publication number: WO2021214615A1
Application number: PCT/IB2021/053183
Authority: WO
Inventors: Gaurav LOHIA
Original assignee: Lohia Corp Limited
Priority date: 2020-04-24
Filing date: 2021-04-18
Publication date: 2021-10-28
Also published as: TWI806038B; TW202206362A

Abstract

An apparatus and a method for changeover of unwinding rolls (29, 30) of fabric (28, 28A) is disclosed. The apparatus comprises a main frame (1), a slidable frame (11) and at least two platforms for fabric rolls (24, 24A). Main frame (1) is equipped with guide rollers (6, 7, 8) to guide path of unwinding fabric. A press assembly (9) applies pressure on fabric (28) to help with easy cutting at the changeover time. The slidable frame (11) slides over main frame (1) and comprises a support wall (21) for mounting roll shafts (17, 18) and front and back rail guides (16, 16A) slidably mounted over the base members (2) of main frame (1). Support platforms (24, 24A) over which carrier platforms (25, 25 A) slide form support structure on which fabric rolls (29, 30) are mounted during fabric preparation stage. All movements are automated but controlled by an operator (34).

Description

AN APPARATUS AND A METHOD FOR CHANGEOVER OF UNWINDING ROLES OF FABRIC

Field Of Invention This invention relates to an apparatus and a method for changeover of unwinding rolls of web material or fabric is disclosed. The apparatus and method is particularly well suited for unwinding webs material on high speed bag forming machines. Background Of Invention

In the production of many packaging products, such as sacks and block bottom bags, plastic fdm or flexible woven packaging webs are typically formed in a large roll. These large rolls are unwound for conversion operations, such as sack making or block bottom bag making.

With the increase in bag forming speed, the high-speed unwinding and further processing web is challenging due to winding quality of rolls. Unwinding of such rolls in a fast and efficient changeover process can also be problematic. For instance, in many traditional operations, web rolls are unwound one roll at a time. After a web roll is unwound, the machine is stopped for the removal of the core and deployment of a new web roll. The downtime associated with web roll changeover creates a substantial reduction in total available run time that reduces the maximum output that can be obtained from a conversion line. Therefore, there is need to develop an apparatus and a system for reducing the roll changeover time and thereby increasing efficiency of conversion line.

Many prior arts describe different kinds of unwinding system and techniques for changing web roll. As an example of conventional unwinding apparatus for fabric web rolls is disclosed in GB 2021520 B (‘520). The patent (‘520) relates to the unwinding stand for a plurality of the fabric web roll with a lifting mechanism by means of which individual fabric roll may be lifted upon their support blocks provided on the two sides of the unwinding stand. The invention (‘520) comprises of system where the arrangement of the rolls are opposite to each other such that if first roll is placed in-line with the bag making machine then to make second roll in-line with the machine the whole apparatus has to be turned which eventually increases the downtime. The further drawback of the invention (‘520) is the use of pneumatic cylinder which may eventually hamper the continuous motion of the roll if there is a lag/drop in air pressure.

Therefore, there is need to develop an apparatus and a system for reducing the roll changeover time and at the same time increasing the efficiency of conversion line. The present invention overcomes the drawbacks unwinding web roll for bag making machine as well as changing roll efficiently to reduce overall downtime.

Objects of Invention:

The main objective of present invention is to provide an apparatus and method which substantially reduce changeover time.

A further objective of present invention is to provide a web roll changeover system that is efficient. Another objective of the present invention is to provide a web roll changeover system that allows efficient changeover between different width web rolls.

Another objective of the present invention is to provide a web roll changeover system that is capable of unwinding different type of web roll material. Brief Description Of Figures:

Figure 1 shows perspective view apparatus of invention

Figures 2 and 2a show perspective view of slidable frame

Figure 3 shows apparatus of invention with fabric roll and fabric path

Figure 4 shows the press assembly and its parts

Figure 5 shows the locking assembly and its parts

Figures 6-A to 6-L illustrate the various steps of the method of the invention as follows:

Figure 6-A shows sliding direction of carrier platform of the apparatus Figure 6-B shows rolling of replacement roll over carrier platform Figure 6-C unlocking the carrier platform and sliding roll towards roll shaft Figure 6-D shows sliding roll shaft downwards to make it concentric with the axis of roll

Figure 6-E shows sliding roll onto the roll shaft up to the distance piece Figure 6-F shows unwinding of fabric over guide rods

Figure 6-G shows unwinding of fabric completed over guide rod and waiting for active roll to finish

Figure 6-H shows lowering of press assembly and cutting the fabric Figure 6-1 shows pasting replacement fabric with the existing fabric Figure 6-J shows raising press assembly and unwinding of fabric begins Figure 6-K shows lowering roll shaft to replace the near to empty roll onto the carrier platform

Figure 6-L shows removal of the near to empty roll from the apparatus

Summary Of Invention:

The apparatus and method as disclosed herein for changeover of unwinding rolls of web material is designed to reduce downtime involved in changing the unwinding roll. The apparatus of the invention has one operational web roll unwinding station or simply an unwinding station, and a standby web roll platform or simply a replacement roll platform. At the unwinding station, there takes place the unwinding activity where the web roll is unwound for supply to the downstream processing station. While one roll (the active roll) is being thus unwound, at the another platform a replacement roll is prepared for eventual unwinding. When the active roll is to be replaced, the fabric is severed from the active roll, the replacement roll is positioned for unwinding, the fabric from the replacement roll is joined with the severed fabric from the active roll, so that unwinding of fabric from the replacement roll can continue without much interruption. The replacement roll now becomes the active roll.

When the fabric needs to be replaced, the same process is repeated. When the fabric from the replacement roll is different from the fabric of the active roll - either in its width, denier, or type - suitable measures are taken so that the joining of the replacement fabric with the fabric being unwound is such that the downstream processes can continue with least possible interruption. The only downtime during the unwinding process is thus the time it takes to sever the fabric from the active roll and the time taken to position the replacement roll for unwinding and joining the replacement fabric onto the fabric of the active roll.

Moreover, since the fabric preparation is carried out simultaneously with unwinding of the active roll the total downtime is significantly reduced. Furthermore, the time taken to position the replacement roll into the unwinding position is also greatly reduced in the system and method of the invention - the significant amount of which also overlaps the unwinding process, thereby further reducing the overall downtime.

List of Parts:

1. Main frame

2. Base members

3. Right arm

4. Left arm 5. Joining element

6. First guide roller

7. Second Guide roller

8. Third guide roller 9. Press assembly

9A. Press arm 9B. Overlaying arm 9C. Handle 9D. Pivot 10. guide rail motor of active roller shaft0A. Guide rail motor of replacement roller shaft

11. Slidable frame

12. First guide rod 12A. Third Guide rod 13. Second guide rod

13 A. Fourth Guide rod

14. Connecting rod

15. Bracket

16. Front rail guide 16A. Back rail guide

17. Inactive roll shaft

18. Active roll shaft

19. Distance piece

20. Drive motor 21. Support wall for roll shaft

22. First base plate 2A. Second base plate

23. First vertical guide rail 3A. Second vertical guide rail 24. First support platform 24A. Second support platform

25. First carrier platform 25A. Second carrier platform

26. Locking assembly 26A. Press element 26B. Spring

26C. Hinge 26D. Projection 26E. Cavity 26F. Position

27. First rail guide 27A. Second rail guide

28. Unwinding Fabric on active roll

28A. Replacement fabric on replacement roll

29. Active roll

30. Replacement roll

31. Unwinding position

32. Drive unit

33. First vertical level adjustment mechanism 33A. Second vertical level adjustment mechanism

34. Operator

Detail Description Of Invention:

The apparatus and the method of invention for changeover of an unwinding roll of fabric is disclosed.

Figure 1 shows an apparatus of present invention, which comprise a main frame (1), a slidable frame (11) and at least two support platforms (24, 24A) for fabric rolls (29, 30)where main frame (1) also comprises a right arm (3) and a left arm (4) which are connected by at least one joining element (5) so as to make the main frame (1) sturdy. A first guide roller (6), a second guide roller (7), and athird guide roller (8) are mounted on the right arm (3) and left arm (4) such that they guide the unwinding fabric (28) unwinding from the active roll (29). The first guide roller (6), second guide roller (7), and third guide roller (8) allow a change in the direction of the fabric (28, 28A) as it unrolls from the respective rolls (29, 30), as shown in Figure 3.

A press assembly (9) is provided to apply pressure on the unwinding fabric (28) so that during roll changeover from the active roll (29) to the replacement roll (30) carrying replacement fabric (28A), the fabric (28) is easily accessible to an operator (34) and can be cut in the a direction transverse to the fabric travel direction without being deviated from its initial position. The main frame (1) may be in the form of a structure such that it is supported by the base members (2), which are also a part of the main frame (1), affixed firmly to the ground onto which the slidable frame (11) slides.

As shown in Figure 2, the slidable frame (11) which slides over the main frame (1) comprises a support wall (21) for roll shafts (17, 18) and at least two members - a front rail guide (16) and a back rail guide (16A) - serving as rail guides for slidable frame (11). The front and back rail guides (16, 16A) are slidably mounted over the base members (2) ofthe main frame (1). The support wall (21) is fixedly connected to the front and back rail guides (16, 16A) using any mechanical means such as welding or bolting or screwing to form a rigid part. Rail guides (16,16A) may be of any type to provide smooth sliding motion to the frame (11) which can be achieved with linear bearing /bush or any mechanical means known to person skill in art.

Further, the slidable frame (11) also has on its one side a first guide rod (12) and a second guide rod (13). On its other side, the slidable frame (11) has a corresponding pair of guide rods, namely a third guide rod ( 12A) and a fourth guide rod (13 A). The first and third guide rods (12, 12A) and the second and fourth guide rods (13, 13A) are connected to each other with connecting rods (14) to make the arrangement robust. The guide rods (12, 13, 12A, and 13A) are provided to facilitate the direction change of the fabric (28, 28A) referred to earlier. The guide rod assembly comprising the guide rods (12, 13, 12A, 13A) interconnected by connecting rods (14) is affixed to the slidable frame (11) by a bracket (15) using any mechanical arrangement such as welding, bolting or screwing.

The slidable frame (11) further constitutes at least one pair of roll shafts referred to earlier - an active roll shaft (18) and an inactive roll shaft (17) - provided to mount the fabric rolls (29, 30) respectively. The active roll shaft (18) and inactive roll shaft (17) are arranged on opposite faces of the support wall (21). Depending on the size of the rolls (29, 30), the vertical level of the roll shafts (17, 18) during their working positions, i.e. the position in which they are mounted at the time of fabric replacement, may vary. This is achieved by providing a vertical level adjustment mechanism (33) which helps the roll shafts (17, 18) to adjust their vertical level. The vertical level adjustment mechanism (33) comprises a first base plate (22) provided on which the roll shaft (18) for active roll (29) is mounted, and a pair of first vertical guide rails (23) that are affixed to the support wall (21) and over which the first base plate (22) slides vertically. The vertical sliding movement of the first base plate (22) is controlled by a first guide rail motor (10) as shown in Figure 2A. A similar arrangement is provided for the inactive roll shaft (17) - a second base plate (22A) which is slidable by a second guide rail motor (10A) on second vertical guide rails (23A) as shown in Figure 2.

Further, a set of sensors (no shown) is provided to determine the position of the movement of the roll shafts (17, 18) in upwards and downwards direction. The motors (10, 10A) are provided with braking arrangement so as to hold the roll shafts (17, 18) at their desired levels in a stationary condition. Since the width of the fabric is variable, the position of the rolls (29, 30) along the roll shafts (17, 18) is also variable. A distance piece (19) is provided on each of the roll shafts (17, 18) to act as a barrier or a stopper for the active roll (29) or replacement roll (30) so that the rolls (29, 30) are aligned centrally to the respective roll shaft (17, 18). The distance piece (19) can be moved over roll shafts (17, 18) and its position can be locked according to the width of the roll (29, 30) loaded on the roll shafts (17, 18).

In one of the embodiments, support wall (21) can be made from multiple structural members or can be made from a single block which is sturdy enough to bear the weight of the roll shafts (17, 18) as well as that of the active roll (29) and the replacement roll (30).

In another embodiment, the front and back rail guides (16, 16A) may be linear members with a tubular or round cross section, or any kind of structural member which can smoothly slide over the base members (2). The length of the front and back guide rails (16, 16A) may be different from each other. One of the said guide rails (16, 16A) comprise a drive unit (32) to drive the slidable frame (11) by a drive motor (20) to and fro as shown in figures 2 and 2A. The direction of motion is shown in Figures 2 and 2A with a dashed arrow.

The activity of mounting the rolls (29, 30) onto the respective roll shafts (18, 17) requires that the rolls (29, 30) are brought into the vicinity of the respective roll shafts (18, 17) and then lifted up so that their centre hole is aligned with the respective roll shafts (18, 17). Following this, at appropriate stages of the changeover operation, the rolls (29, 30) are moved laterally so as to slide them onto the respective roll shafts (18, 17). During the mounting operation of the rolls (29, 30) onto the respective roll shafts (18, 17), the said rolls are supported on respective support platforms (24, 24A): a first support platform (24) for the active roll (29) and a second support platform (24A) for the replacement roll (30). The support platforms (24, 24A) are firmly affixed to the ground by any kind of mechanical means such as bolting or grouting or clamping and are aligned such that the corresponding roll shafts (18, 17) are concentric to each other facing opposite to the support wall for roll shaft (21).

Both the support platforms for roll (24A, 24) can be of identical construction. The mounting operation of the rolls (29, 30) also involves their lateral movement which is facilitated by respective carrier platforms: a first carrier platform (25) for the active roll (29) and a second carrier platform (25A) for the replacement roll (30). The carrier platforms (25, 25 A) are slidable over the respective support platforms (24, 24A) with the help of respective pairs of rail guides - a pair of first rail guides (27) and a pair of second rail guides (27A) - that are affixed to respective support platforms (24, 24A). A locking assembly (26) is provided to lock the slidable carrier platforms (25, 25A) at the position (26F) so that the replacement roll (30) can be mounted over it without any mechanical movement.

Figure 3 shows the apparatus with an active roll (29) and a replacement roll (30) wherein the unwinding fabric (28) is being unwound from the active roll (29). It also shows with a dashed arrow the direction of feeding of the unwinding fabric (28). The replacement roll (30) is shown in standby position over the second carrier platform (25 A) slidably supported by the second support platform (24A). Fabric being unwound may need replacing for one of many reasons such as the active roll (29) coming to an end of unwinding fabric (28) or change in type of fabric (denier, gsm, print/colour, fabric width) being necessary.

Figure 4 shows the press assembly (9) which comprises at least one pair of press arms (9 A) which are connected together by an overlaying arm (9B). A handle (9C) is provided to move the press assembly manually towards and away from the unwinding fabric (28) about a pivot (9D). Such motion can be achieved by a hinge mechanism or by bush and pin arrangement to swing the press assembly (9) about an axis. During roll changeover, the unwinding fabric (28) of the active roll (29) is held in place under pressure by the press assembly (9) before cutting so that the unwinding fabric (28) does not deviate from its present condition. The press arm (9A) can be metallic or non-metallic and of which one end comprises of a handle (9C) and another end pivot (9D). Further, the overlaying arm (9B) can also be metallic or non-metallic of enough strength to press the unwinding fabric (28) and restricts its movement.

Figure 5 shows the locking assembly which comprises press element (26A), spring element (26B) and a hinge (26C) wherein during the process of the preparation of the replacement roll (30), the first/second carrier platform (25/25A) is made to slide over first/second support platform (24/24 A) to a position A. As soon as the first/second carrier platform (25/25A) reaches the position A, the projection (26D) gets inserted into the cavity (26E) and locks the position of first/second carrier platform (25/25 A). Locking is done so that first/second carrier platform (25/25A) does not move while loading of replacement roll (30). When the loading of the replacement roll (30) is done, operator (34) presses the press element (26A) manually and thereby releases the projection (26D) from cavity (26E). The movement of press element (26A) to and fro is governed by hinge (26B) and a spring (26B), the said spring (26B) exert a back force so that after release, press element (26A) assumes its original position.

As an example, a bag making machine which is running at a speed of 120 meters per minute and having bag output of 120 bags per min using conventional unwinding system. It was observed during roll changeover the machine stops and operator takes 5 mins to change the roll and again start the machine and in such case, there is a production loss for 5 minutes i.e. of 600 bags. In the same machine when operator uses the inventive unwinding system wherein it was observed that the roll changeover time, the down time is reduced to 2 minutes, thus reducing production loss to 240 bags from 600 bags.

Figures 6-A to 6-L show inventive method of roll changeover from an active roll (29) to a replacement roll (30) such that the down time during the changeover operation is minimised. The method to change from active roll (29) to a replacement roll (30) involves following steps: a. an operator (34) inspects the fabric for suitability for making the objects and prepares the starting portion of the fabric (28A) of the replacement roll (30) for joining with the fabric (28) of the active roll (29). The top layers of rolled fabric of the replacement roll (30) may have become damaged during transport/handling. These layers may need removing before unwinding. The operator thus ‘prepares’ the replacement roll (30) for unwinding with its visible end ready for joining with the fabric that is being unwound. This activity may be carried out near the unwinding station or at any place suitable for this activity. b. before loading the replacement roll (30) onto the second carrier platform (25A), the operator slides (sliding movement shown by a dashed arrow in Figure 6-A) the second carrier platform (25 A) to a position A shown by a solid line in Figure 6-A and locks it. c. the replacement roll (30) is placed, preferably by rolling it over, onto the second carrier platform (25A) as shown in Figure 6-B. d. the operator (34) presses the press element (26A) to release the second carrier platform (25 A) and slides it over the second support platform (24A) towards the inactive roll shaft (17) as shown in Figure 6-C. e. preferably simultaneously, the second base plate (22A) slides vertically till the axis of the inactive roll shaft (17) becomes concentric with the axis of the replacement roll (30) as shown in Figure 6-D. f. the sliding second carrier platform (25A) is further moved such that the replacement roll (30) inserts into the inactive roll shaft (17) and stops once it reaches the distance piece (19) that acts as a barrier for further advancement as shown in Figure 6-E. g. the fabric (28A) is unwound by the operator and is overlaid onto the third and fourth guide rods (12A and 13A) as shown in Figure 6-F, 6-G. h. once the fabric (28) from the active roll (29) comes near its end as shown in Figure 6-G, it is stopped by the operator from unwinding. The operator lowers the press assembly (9) with the help of handle (9C) onto the fabric (28) such that the fabric (28) is held down in position and cut transversely across its width at a suitable point, and the remaining fabric (28) (which is hanging loose from the point of cut) is wound back on the active roll (29) as shown in Figure 6-H. i. the slidable platform (11) is now moved by the drive motor (20) laterally to move the active roll (29) away from the unwinding position (31) such that it assumes an inactive position, and whereby said replacement roll (30) is placed in the unwinding position (31). j . the fabric (28A) from the replacement roll (30) is now passed over the first guide roller (6) and is joined with already overlaid fabric (28) (which was unwound from the active roll (29)) by any mechanical or electromechanically means such as welding, gluing, pasting as shown in Figure 6-1. k. the press assembly (9) is now raised so that unwinding of the fabric (28A) from the replacement roll (30) begins as shown in Figure 6-J.

The replacement roll (30) has now become the active roll (29), and the previously active roll is now an empty fabric roll. The empty fabric roll is removed from its shaft and away from the carrier platform (25) as shown in Figure 6-K & 6-L so that a new replacement roll may be mounted on it, when the currently active roll needs replacing. It is evident from the foregoing discussion that the invention has a number of embodiments.

In the preferred embodiment, an apparatus for changeover of an unwinding roll of fabric of the invention comprises the following; a main frame (1) over which said fabric unwinds, and which is affixed to ground by its base members (2), a slidable frame (11), which is equipped to support two rolls of said fabric, namely an active roll (29) and a replacement roll (30), and which is capable of sliding in a direction parallel to the axes of said rolls (29, 30), at least two support platforms (24, 24A) on which said carrier platform (25, 25 A) is slidable.

The key aspect of the preferred embodiment is that the slidable frame (11) is capable of sliding in a first direction to place said active roll (29) in the unwinding position while it supports said replacement roll (30) for pre-unwinding fabric preparation, and wherein upon completion of required amount of unwinding of fabric from said active roll (29), said sliding frame (11) is capable of sliding in a second direction to place said replacement roll (30) in the unwinding position, wherein said sliding in first and second directions takes place on corresponding said support platform (24 or 24A), and wherein said support platforms (24, 24A) are firmly affixed to the ground by any kind of mechanical means such as bolting or grouting or clamping.

In another embodiment of the apparatus of the invention, the main frame (1) comprises a right arm (3) and a left arm (4) which are connected by at least one joining element (5) so as to make the main frame (1) sturdy, a first guide roller (6), a second guide roller (7), and a third guide roller (8) that are mounted on the right arm (3) and left arm (4) in a position to guide the fabric (28) unwinding from the active roll (29). In yet another embodiment of the apparatus of the invention, a press assembly (9) is provided to apply pressure on the fabric (28) during the unwinding operation.

In still another embodiment of the apparatus of the invention, the slidable frame (11) comprises a support wall (21) on the opposite faces of which are mounted an inactive roll shaft (17) for mounting said replacement roll (30) and an active roll shaft (18) for mounting said active roll (29); and at least two members - a front rail guide (16) and a back rail guide (16A) - being slidably mounted over said base members (2), on its one side a first guide rod (12) and a second guide rod (13), and on its other side, a corresponding third guide rod (12A) and a fourth guide rod (13 A), wherein said first and third guide rods (12, 12A) and the second and fourth guide rods (13, 13 A) are connected to each other to with connecting rods (14).

In a further embodiment of the apparatus of the invention, the support wall (21) is fixedly connected to the front and back rail guides (16, 16A) using any mechanical means such as welding or bolting or screwing to form a rigid part.

In a yet further embodiment of the apparatus of the invention, the replacement fabric (28A) is arranged around said respective guide rods (12A and 13A) to expose said replacement fabric (28 A) for preparation at the time of fabric changeover.

In a still further embodiment of the apparatus of the invention the assembly of guide rods (12, 13, 12A, 13A) interconnected by connecting rods (14) is affixed to the slidable frame (11) by a bracket (15) using any mechanical arrangement such as welding, bolting or screwing.

In another embodiment of the apparatus of the invention, the vertical level of the active roll shaft (18) during its working position is adjusted using a first vertical level adjustment mechanisms (33) comprising a first base plate (22) on which the active roll shaft (18) is mounted, and a pair of first vertical guide rails (23) that are affixed to the support wall (21) and over which the first base plate (22) slides vertically.

In yet another embodiment of the apparatus of the invention, the vertical level of the inactive roll shaft (17) during its working position is adjusted using a second vertical level adjustment mechanisms (33 A) comprising a second base plate (22A) on which the inactive roll shaft (17) is mounted, and a pair of second vertical guide rails (23A) that are affixed to the support wall (21) and over which the second base plate (22A) slides vertically.

In one more embodiment of the apparatus of the invention, the vertical sliding movement of the first base plate (22) is controlled by a first guide rail motor (10), and the vertical sliding movement of the second base plate (22A) is controlled by a second guide rail motor (lOA)wherein said motors (10, 10A) are provided with braking arrangement so as to hold the roll shafts (17, 18) at their desired levels in a stationary condition.

In still another embodiment of the apparatus of the invention, a set of sensors is provided to determine the position of the movement of the roll shafts (17, 18) in upwards and downwards direction.

In still another embodiment of the apparatus of the invention, a distance piece (19) is provided on each of the roll shafts (17, 18) as a barrier or a stopper for the rolls (29, 30) for aligning the respective rolls (29, 30) centrally on their respective roll shafts (18, 17).

In a further embodiment of the apparatus of the invention, the support wall (21) is made from multiple structural members or from a single block. In a yet further embodiment of the apparatus of the invention, the front and back rail guides (16, 16A) are linear members with a tubular or round cross section, or any kind of structural member capable of smoothly sliding over said base members (2), and wherein the length of the front and back guide rails (16, 16A) may be different from each other.

In a still further embodiment of the apparatus of the invention, any one of said guide rails (16, 16A) comprises a drive unit (32) to drive the slidable frame (11) by a drive motor (20) to and fro.

In another embodiment of the apparatus of the invention, a first carrier platform (25) provided which is slidable over said first support platform (24) on a pair of first rails (27) affixed to said first support platform (24), and a second carrier platform (25A) provided which is slidable over said second support platform (24A) on a pair of second rails (27A) affixed to said second support platform (24A).

In yet another embodiment of the apparatus of the invention, the carrier platforms (25 and 25A) are locked in position on respective support platforms (24 and 24A) with a locking assembly (26) is provided on each of said support platforms (24 and 24A).

In yet another embodiment of the apparatus of the invention, the locking assembly (26) comprises a press element (26A), spring element (26B) and a hinge (26C) wherein said press element (26A), when pressed, lowers a projection (2D) attached to said press element (26A) and when said press element is released, said projection comes back up with the help of said spring element (2B), and engages into a cavity (26E) provided in the first and second carrier platforms (25, 25 A) In still another embodiment of the apparatus of the invention, the said press assembly (9) comprises at least one pair of press arms (9A) which are connected together by an overlaying arm (9B), a handle (9C) provided to move the press assembly manually towards and away from the unwinding fabric (28) about a pivot (9D), said movement being achieved by a hinge mechanism or by bush and pin arrangement to swing the press assembly (9) about an axis.

In one more embodiment of the apparatus of the invention, the said press arm (9A) and said overlaying arm (9B) are made of metallic or non-metallic materials and of which one end comprises of a handle (9C) and another end pivot (9D).

The preferred embodiment of the method of changeover of an unwinding roll of fabric on the apparatus as described in the aforementioned embodiments comprises the following steps: a. inspecting and preparing the starting portion of the replacement fabric (28A) of a replacement roll (30); b. sliding said second carrier platform (25 A) over the second support platform (24A) and locking it in position and rolling the said inspected and prepared replacement roll (30) onto said second carrier platform (25A); c. pressing the press element (26A) to release the second carrier platform (25 A) carrying said replacement roll (30) and sliding it over said second support platform (25) towards the inactive roll shaft (17) as shown in Figure 6-C. d. using second vertical level adjustment mechanism (33A), sliding the second base plate (22A) vertically to align the axis of the inactive roll shaft (17) affixed to said second base plate (22) concentrically with the axis of the replacement roll (30); e. sliding second carrier platform (25 A) further to mount said replacement roll (30) over said inactive roll shaft (17) and keep sliding it till it reaches the distance piece (19); f. unwinding replacement fabric (28A) and arranging it around the third and fourth guide rods (12A and 13A); g. stopping unwinding of fabric (28) from the active roll (29) and holding it down in position using the press assembly (9) and making a transverse cut in it; h. moving said slidable platform (11) to carry said active roll (29) away from the unwinding position (31) to an inoperative position, and whereby said replacement roll (30) is placed in the unwinding position (31); i. passing fabric (28A) from the replacement roll (30) over the first guide roller (6) to join with already overlaid fabric (28), thereby completing the changeover from active fabric (28) to replacement fabric (28A).

In an embodiment of the method, the vertical sliding movement of said second base plate (22A) of said step d is controlled by a second guide rail motor (10A), and wherein said motors (10A) is provided with braking arrangement so as to hold the inactive roll shaft (17) at their desired levels in a stationary condition.

In another embodiment of the method of the invention, the position of the inactive roll shaft (17) movement in upwards and downwards direction in step d is determined by sensors.

In yet another embodiment of the method of the invention, the lateral movement of slidable frame (11) is carried out by a by a drive motor (20) controlled by a drive unit (32).

Claims

Claims:

1. An apparatus for changeover of an unwinding roll of fabric characterised in that said apparatus comprises: a main frame (1) over which said fabric im winds, and which is affixed to ground by its base members (2), over which an active roll (29) of fabric unwinds, a slidable frame (11), which is equipped with a support wall (21) to support two rolls of said fabric, namely said active roll (29) and a replacement roll (30), and which is capable of sliding in a direction parallel to the axes of said rolls (29, 30), at least two support platforms (24, 24A) on which said main frame (1) is slidable wherein said slidable frame (11) is capable of sliding in a first direction to place said active roll (29) in the unwinding position while it supports said replacement roll (30) for pre-unwinding fabric preparation, and wherein upon completion of required amount of unwinding of fabric from said active roll (29), said sliding frame (11) is capable of sliding in a second direction to place said replacement roll (30) in the unwinding position, wherein said sliding in first and second directions takes place on corresponding said support platform (24 or 24A) which are firmly affixed to the ground by any kind of mechanical means such as bolting or grouting or clamping.

2. The apparatus as claimed in claim 1, wherein said main frame (1) comprises a right arm (3) and a left arm (4) which are connected by at least one joining element (5) so as to make the main frame (1) sturdy, a first guide roller (6), a second guide roller (7), and a third guide roller (8) that are mounted on the right arm (3) and left arm (4) in a position to guide the fabric (28) unwinding from the active roll (29).

3. The apparatus as claimed in claims 1 and 2, wherein a press assembly (9) is provided on said main frame (1) to apply pressure on the fabric (28) during the fabric changeover operation.

4. The apparatus as claimed in claims 1 to 3, wherein said slidable frame (11) has an inactive roll shaft (17) for mounting said replacement roll (30) and an active roll shaft (18) for mounting said active roll (29), both said shafts (17, 18) mounted on opposite faces of said support wall (21); and at least two members - a front rail guide (16) and a back rail guide (16A) - being slidably mounted over said base members (2), on its one side a first guide rod (12) and a second guide rod (13), and on its other side, a corresponding third guide rod (12A) and a fourth guide rod (13 A), wherein said first and third guide rods (12, 12A) and the second and fourth guide rods (13, 13A) are connected to each other to with connecting rods (14).

5. The apparatus as claimed in claims 1 to 4, wherein said support wall (21) is fixedly connected to the front and back rail guides (16, 16A) using any mechanical means such as welding or bolting or screwing to form a rigid part.

6. The apparatus as claimed in claims 4 and 5, wherein said replacement fabric

(28A) is arranged around said third and fourth guide rods (12A and 13A) to expose said replacement fabric (28A) for preparation at the time of fabric changeover.

7. The apparatus as claimed in claims 4 to 6, wherein the assembly of guide rods (12, 13, 12A, 13A) interconnected by connecting rods (14) is affixed to the slidable frame (11) by a bracket (15) using any mechanical arrangement such as welding, bolting or screwing.

8. The Apparatus as claimed in claims 4 to 7, wherein the vertical level of the active roll shaft (18) during its working position is adjusted using a first vertical level adjustment mechanism (33) comprising a first base plate (22) on which the active roll shaft (18) is mounted, and a pair of first vertical guide rails (23) that are affixed to the support wall (21) and over which the first base plate (22) slides vertically.

9. The Apparatus as claimed in claims 4 to 8, wherein the vertical level of the inactive roll shaft (17) during its working position is adjusted using a second vertical level adjustment mechanism (33A) comprising a second base plate

(22A) on which the inactive roll shaft (17) is mounted, and a pair of second vertical guide rails (23 A) that are affixed to the support wall (21) and over which the second base plate (22A) slides vertically. 10. The apparatus as claimed in claims 4 to 9, wherein the vertical sliding movement of the first base plate (22) is controlled by a first guide rail motor (10), and the vertical sliding movement of the second base plate (22 A) is controlled by a second guide rail motor (10A), and wherein said motors (10,

10 A) are provided with braking arrangement so as to hold the roll shafts (17, 18) at their desired levels in a stationary condition.

11. The apparatus as claimed in claims 1 to 10, wherein a set of sensors is provided to determine the position of the movement of the roll shafts (17, 18) in upwards and downwards direction.

12. The apparatus as claimed in claims 1 to 11, wherein a distance piece (19) is provided on each of the roll shafts (17, 18) as a barrier or a stopper for the rolls (29, 30) for aligning the respective rolls (29, 30) centrally on their respective roll shafts (18, 17).

13. The apparatus as claimed in claims 1 to 12, wherein said support wall (21) is made from multiple structural members or from a single block.

14. The apparatus as claimed in claims 4 to 13, wherein said front and back rail guides (16, 16A) are linear members with a tubular or round cross section, or any kind of structural member capable of smoothly sliding over said base members (2), and wherein the length of the front and back guide rails (16,

16 A) may be different from each other.

15. The apparatus as claimed in claims 4 to 14, wherein any one of said guide rails (16, 16A) comprises a drive unit (32) to drive the slidable frame (11) by a drive motor (20) to and fro.

16. The apparatus as claimed in claims 4 to 15 wherein a first carrier platform (25) provided which is slidable over said first support platform (24) on a pair of first rails (27) affixed to said first support platform (24), and a second carrier platform (25 A) provided which is slidable over said second support platform (24 A) on a pair of second rails (27 A) affixed to said second support platform (24 A).

17. The apparatus as claimed in claim 1, wherein said carrier platforms (25 and 25 A) are locked in position on respective support platforms (24 and 24A) with a locking assembly (26) provided on each of said support platforms (24 and 24 A).

18. The apparatus as claimed in claim 17, wherein said locking assembly (26) comprises a press element (26A), spring element (26B) and a hinge (26C) wherein said press element (26A), when pressed, lowers a projection (26D) attached to said press element (26A) and when said press element is released, said projection comes back up with the help of said spring element (26B), and engages into a cavity (26E) provided in the first and second carrier platforms (25, 25A).

19. The apparatus as claimed in claims 3 to 18, wherein said press assembly (9) comprises at least one pair of press arms (9A) connected together by an overlaying arm (9B), a handle (9C) provided to move the press assembly manually towards and away from the unwinding fabric (28) about a pivot (9D), said movement being achieved by a hinge mechanism or by bush and pin arrangement to swing the press assembly (9) about an axis.

20. The apparatus as claimed in claim 19 said press arm (9A) and said overlaying arm (9B) are made of metallic or non-metallic materials and of which one end comprises of a handle (9C) and another end pivot (9D).

21. A method of changeover of an unwinding roll of fabric on the apparatus as claimed in claims 1 to 20, characterised in that said method comprises the steps of: a. inspecting and preparing the starting portion of the replacement fabnc (28A) of the replacement roll (30); b. sliding said second carrier platform (25 A) over the second support platform (24A) and locking it in position and rolling the said inspected and prepared replacement roll (30) onto said second carrier platform (25 A); c. pressing the press element (26A) to release the second carrier platform (25A) carrying said replacement roll (30) and sliding it over said second support platform (24A) towards the inactive roll shaft (17) as shown in Figure 6-C. d. using second vertical level adjustment mechanism (33A), sliding the second base plate (22A) vertically to align the axis of the inactive roll shaft (17) affixed to said second base plate (22) concentrically with the axis of the replacement roll (30); e. sliding second carrier platform (25A) further to mount said replacement roll (30) over said inactive roll shaft (17) and keep sliding it till it reaches the distance piece (19); f. unwinding replacement fabric (28 A) and arranging it around the third and fourth guide rods (12A and 13A); g. stopping unwinding of unwinding fabric (28) from the active roll (29) and holding it down in position using the press assembly (9) and making a transverse cut in it; h. moving said slidable platform (11) to carry said active roll (29) away from the unwinding position (31) to an inoperative position, and whereby said replacement roll (30) is placed in the unwinding position (31); i. passing said fabric (28A) from the replacement roll (30) over the first guide roller (6) and is joined with already overlaid fabric (28), thereby completing the changeover from active fabric (28) to replacement fabric (28 A).

22. The method as claimed in claim 21, wherein said vertical sliding movement of said second base plate (22A) of said step d is controlled by a second guide rail motor (10A), and wherein said motors (10A) is provided with braking arrangement so as to hold the inactive roll shaft (17) at their desired levels in a stationary condition.

23. The method as claimed in claims 21 and 22, wherein the position of the inactive roll shaft (17) movement in upwards and downwards direction in step d is determined by sensors.

24. The method as claimed in claims 21 to 23, wherein the lateral movement of slidable frame (11) is carried out by a by a drive motor (20) controlled by a drive unit (32).

25. The method as claimed in claim 21 , wherein all steps a to i are carried out by an operator (34).

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