Field of the Invention
This invention relates to the apparatus for holding the cop/conical tube by the auto doffer of the textile machine for the exchange of cops with conical tubes. More particularly this invention relates to the gripper assembly.
Background and prior art
The gripper assembly includes a plurality of tube gripping devices each for individually gripping a tube to support the tube during the various transfer operations.
In US Patent No. 4,472,934 a pneumatic gripper for bobbin changer devices with an elastically deformable collar in the gripper housing is used. The gripper housing and the collar are of bell-shaped construction. The collar is inserted into the gripper housing. The collar overlaps the edge of the gripper housing and is pressed air tightly against the edge by means of a screw collar ring.
Holding and releasing of the cop and the conical tube during the exchange of cop with the conical tube is achieved with the help of the gripper assembly attached to the gripper beam of the auto doffer of the textile machine. The gripper assembly essentially comprises an inflatable membrane made of elastomer material. For the purpose of holding and releasing of the cop/conical tube as the case may be the membrane is inflated / deflated as the case may be. Mostly compressed air is employed for inflating the membrane.
The known grippers comprise a gripper body which is made of polymer material, a flexible inflatable membrane member made of elastomer material and sealing rings. The flexible member is positioned in the body of the gripper and retained

by the sealing rings arranged on both the ends of the gripper body. In the event of damage caused to the elastomer member, it will result in the escape of air and the malfunctioning of the gripper.
For this purpose the sealing rings are to be removed, the flexible member has to be exchanged with good one and the sealing rings are to be assembled by exerting pressure means. This may cause mechanical damage to the flexible membrane.
There is a need for a holder assembly in which the flexible member can be easily replaced without causing damage to the flexible membrane so as not to affect the productivity and also to provide a greater holding area for the cop/bobbin. The applicants after extensive work have found that such needs could be met by providing a novel locking design for the holder assembly.
Objects of the invention
Accordingly, one object of the present invention is to provide a holder assembly, which will facilitate easy replacement of the membrane with out causing mechanical damage as well as without the requirement of means for applying pressure.
Another object of the present invention is to provide a gripper in which the elastomer member can be replaced easily at the machine site itself.
Another object of the present invention is to provide a locking nut assembly easily operable by hand.

Summary of the invention
According to one aspect of the present invention there is provided an improved
holder assembly for holding the cop/conical tube by auto doffer of the textile
machine, said assembly comprising a central body ;
an inflatable flexible member; and
locking means;
said central body defining a circular portion
wherein the central body comprises at least two projections operatively located at
ends of outer part of the central body,
wherein said locking means being operatively engaged with the projections on
the central body thereby holding the locking means and projections firmly against
each other.
Detailed description of invention
According to an embodiment of the invention the locking means is comprised of at least a pair of locking rings and locking nuts adapted to engage each other. The locking means comprises locking rings and locking nuts. The flexible member is held inside the circular portion of the central body by the locking means. The locking means clamps the flexible member with the central body in which it is housed in a manner such that it communicates with said projections of the central body.
The locking means has a unique arrangement of tapered projections provided at the ends of the outer part of central body which communicates with corresponding tapered projections in the inner surface of the locking nut such that upon tightening the locking nut engages by the engagement of the corresponding tapered projections. In the tightened position the tapered

projection hold against each other firmly and can be disengaged easily by rotating the locking nut in the appropriate direction.
The tapered projections are at least two in number on the sides of the central body and inside the locking nut and preferably the number of the projections is three and most preferably four. Between the projections provided on the central body as well as the locking nut there is sufficient space so that the projections of the nut can pass through the edges of the central body and get engaged with the projection of the central body when the locking nut is tightened.
The flexible member is substantially cylindrical and is held at the ends by circular rigid members which may be of metal or other suitable polymeric material. The locking rings have inner diameter which is greater than the outer diameter of the said circular rigid members such that the locking ring engages against the circular rigid member firmly when assembled.
The use of the locking rings and locking nuts make the construction cheap and simple and the assembling or disassembling of the gripper assembly is much more user-friendly compared to the known constructions. The simplicity of the construction would enable the replacement of the flexible member at the machine site itself and this will not affect the productivity and will also considerably ease the operation.
Brief description of the accompanyinq drawings
Figure 1 illustrates isometric view of the holder assembly of the present invention in an assembled condition.
Figure 2 illustrates the various parts of the assembly in a disassembled condition in the sequence they are assembled.

Detailed Description of the accompanyinq drawings
The invention will now be illustrated with reference to accompanying drawings, which are provided for ready and better understanding of the invention. The drawings represent only a specific working embodiment of the assembly according to the invention although variants of the assembly may be made within the scope and ambit of the present invention.
In fig 1, the assembled holder assembly is shown in which the locking nuts 5 are held to both ends of the central body (1) which is mounted on a base (B).
As per fig 2, the central body (1) is having an inlet for fluid entry and four numbers of tapered projection (2) at the end of the body for positive locking purpose. The flexible member (3) is to hold either Cop/Bobbin as the case may be. Locking ring (4) and locking nut (5) has depression at its inner side for locking purpose and outer shape/round portion with serration for easy hand tightening purpose. The locking nut outside surface is of hexagonal shape. However, this shape does not limit the scope of the present invention and any other shape can be used.
The holder assembly consists of a central body (1), inflatable flexible member (3) which is a substantially cylindrical body. The flexible member (3) has projecting edges (3a) located circumferentially at the ends thereof so that it can firmly engage into the locking ring (4) which is pressed on the edges (3a). The outer diameter of the locking ring (4) is such that it concentrically fits into the inner cavity of the locking nut (5) firmly into a groove (5a) in the inner part of the locking nut (5). The locking nut (5) also has four numbers of tapered projections (5b) integrally provided at the lower end of the inner part of the nut. The assembly is made by inserting the flexible member (3) inside the central body (1) and thereafter pressing the locking ring (4) on the edges (3a) of the flexible

member and the locking nut (5) is finally assembled on the locking ring (4) and pressed on the edges of the central body (1) and thereafter tightened by rotating the nut (5) such that the tapered projections (2) on the central body and the tapered projection (5b) in the inner part of the locking nut are engaged.
The construction of the assembly enables the use of the tubular flexible member, damage to the said flexible member is avoided due to the construction of the assembly according to the invention because no direct pressure is exerted on the flexible member. As a result of the novel construction of the assembly the flexible member is housed without any difficulty and clamped with the central body by the lock nuts.
The unique locking design is made more simple so that assembling or disassembling will be more user-friendly. In case of any damage happened to the flexible member within shortest possible time the same can be replaced. Further the assembly can be made in cottage industries which further cuts down the cost of the assembly and eventually provides additional efficiency to the machine during use.
The invention has been shown and described in a preferred form only and many variations may be made in the invention, which will still be comprised within its spirit. It is understood, therefore, that the invention is not limited to the details cited above. Number of projections, number of sides of the nut herein described do not limit the scope of the present invention. The same can be replaced by its technical equivalence and yet the invention can be performed. The structure thus conceived is susceptible of numerous modifications and variations, all the details may furthermore be replaced with elements having technical equivalence. In practice the materials and dimensions may be any according to the requirements, which will still be comprised within its true spirit.

We claim
1. An improved holder assembly for holding the cop/conical tube by auto
doffer of the textile machine, said assembly comprising
a central body;
an inflatable flexible member; and
locking means;
said central body defining a circular portion
wherein the central body comprises at least two projections operatively
located at ends of outer part of the central body,
wherein said locking means being operatively engaged with the
projections on the central body thereby holding the locking means and
projections firmly against each other.
2. Holder assembly as claimed in claims 1 and 2, wherein the central body comprises plurality of projecting edges circumferentially located on the central body.
3. Holder assembly as claimed in claim 1, wherein the locking means comprises at least a pair of locking rings having depression at its inner side adapted for locking purpose.
4. Holder assembly as claimed in claim 4, wherein the locking ring further comprises outer round portion with serration adapted for easy tightening.
5. Holder assembly as claimed in claim 1 further comprises locking nut having depression at its inner side adapted for locking purpose.

6. Holder assembly as claimed in claim 1, wherein the central body
comprises preferably 3 projections, most preferably 4 projections.
7. Holder assembly as claimed in claim 5, wherein the locking nut comprises
preferably 3 projections, most preferably 4 projections.
8. Holder assembly as claimed in any of the preceding claims wherein the locking rings being concentrically engaged with the locking nut in a manner to provide tight fit on the central body by way of rotation of the locking nut.
9. An improved holder assembly as substantially herein described and illustrated with reference to accompanying figures.