EP1378476B1

EP1378476B1 - Traversing drum

Info

Publication number: EP1378476B1
Application number: EP20030014622
Authority: EP
Inventors: Hidetoshi Roureru Couto Muromachi 310 Kimura; Kenji Muraya; Ichiro Hidaka
Original assignee: Murata Machinery Ltd
Current assignee: Murata Machinery Ltd
Priority date: 2002-07-01
Filing date: 2003-06-26
Publication date: 2006-11-22
Anticipated expiration: 2023-06-26
Also published as: DE60309781T2; CN100368274C; EP1378476A3; CN1468795A; JP2004035127A; EP1378476A2; DE60309781D1; JP3744475B2

Description

The present invention relates to a traversing drum according to the preamble of claim 1.

Background of the Invention

In a yarn winding device such as an automatic winder, when a yarn is wound around a package, a traversing drum that is in pressure contact with the package is externally rotatively driven to wind the yarn while rotating the package. An endless guide groove is formed in the surface of the traversing drum as traversing means for winding the yarn around the package uniformly in an axial direction of the package.
Such a traversing drum may be formed of ceramic material as a one-piece, solid drum body as disclosed by GB-A-531 595 also defining the preamble of claim 1.
Traversing drums formed integrally of ceramic material have the disadvantages of having a very large mass thus affording high power drive motors. In view of these problems, it is the object of the present invention to solve these problems and to provide a traversing drum made of ceramics which is rigid, but light.
This object is accomplished by the features defined in the charaterizing portion of claim 1.
When a traversing drum is manufactured using an inner cylinder and an outer cylinder which are integrally molded using a ceramic burned member, it is rigid and light even if the cylinders are thin. It is thus possible to significantly reduce the power consumption of the rotative driving source for the traversing drum and to extend its lifetime.
Since the inner cylinder and the outer cylinder are intermittently connected together using ribs, the rigidity of the traversing drum can be improved.
The ribs may be used to connected the inner cylinder to the groove bottom of the guide groove formed in the surface of the outer cylinder.
The inner cylinder may be installed over a rotating shaft via bearings each having rubber rings installed on its outer peripheral surface. It is thus possible to absorb a difference in thermal expansion based on a difference in material between the metall rotating shaft of the rotative driving source and the ceramic traversing drum. This prevents, for example, a failure to transmit a rotative driving force owing to a possible gap between the rotating shaft and the traversing drum.

Brief Description of the Drawings

Figure 1 is a view of a part of an automatic winder comprising a traversing drum according to a first embodiment of the present invention.
Figure 2 and 3 are vertical sectional views of a traversing drum according to a second and third embodiment.
Figure 4 is a vertical sectional view showing a mounting structure between the inner cylinder and bearings the traversing drum.

Detailed Description of the Preferred Embodiments

Figure 1 shows an automatic winder comprising a traversing drum 1 installed over a rotating shaft 2. A motor 4 is fixed to a frame 3 of the automatic winder as a rotative driving source. The rotating shaft 2 of the motor 4 has two step portions. Two bearings 5A, 5B are externally fitted over the step portions The spacing between the bearings 5A, 5B is held by a spacer 6. The two bearings 5A, 5B are fixed by screwing a nut 7 over the rotating shaft 2.
A winding package P contacts the traversing drum 1 to drive the winding package P. An endless guide groove 8 is formed in an outer peripheral surface of the traversing drum 1 to traverse a yarn Y in the direction along a rotational center line C of the traversing drum 1. A drum main body including the groove 8 is integrally molded of a ceramic burned member. The drum main body is composed of an outer cylinder 9 having the guide groove 8 formed in its outer peripheral surface and an inner cylinder comprising partial cylinders 10A, 10B as bearing supporting portions. The outer cylinder 9 and the inner cylinder 10A, 10B are integrally molded of the ceramic burned member. The traversing drum 1 may be manufactured using a lost wax process. In this case the traversing drum 1 is manufactured as a product by pouring wax into a die to form a mold material, pouring a ceramic material on the mold material, drying and solidifying the ceramic material, then heating the ceramic material to melt and remove the wax to form a molding base for the traversing drum 1 even of a complicated shape, subsequently baking the molding base at a high temperature, and finishing the molding base by subjecting it to surface treatment. In this respect, after the wax has been melted and removed, the remaining wax may be further completely burned before the molding base is baked at a high temperature.
The traversing drum 1 is thus manufactured so as to have a double cylinder structure including the inner and outer cylinders. The inner cylinder 10A, 10B of the traversing drum 1 is externally fitted over two bearings 5A, 5B fixedly installed on the two step portions of the rotating shaft 2. An end plate 13 is fixed by screws 14 to a disk portion of a wheel 12 fixed to the tip of the rotating shaft 2 via a set screw 11.
The traversing drum 1 configured in this manner has a very small mass. It also serves to reduce loads on the motor 4, which thus has significantly reduced power consumption. It is also possible to extend the lifetime of the drum motor 4 itself. Furthermore, the groove bottom of the guide groove 8 in the traversing drum 1 and the inner cylinders 10A, 10B as a bearing supporting portion are integrally connected together. This makes it possible to increase the rigidity of the whole traversing drum 1 including the outer cylinder 9.
Figure 2 shows a second embodiment of traversing drum 15 having, an inner cylinder 16 molded of a single continuous cylinder, an outer cylinder 17 formed integrally with the inner cylinder 16 at one end of it and at the other end fixed to the disk portion of the drum wheel 12 via screws 14. Accordingly, the drum as a whole has a high rigidity, so that the groove bottom of the guide groove 8 and the inner cylinder 16 are not integrally connected together.
Figure 3 shows a third embodiment of traversing drum 18 being a combination of the first and second embodiment. The inner cylinder 16 is molded of a single continuous cylinder. The outer cylinder 17 and the inner cylinder 16 are integrated together at one end. The groove bottom of the guide groove 8 and the inner cylinder 16 are integrally connected together. The traversing drum 18 has an increased rigidity because the inner cylinder 16 and the outer cylinder 17 are integrally molded at one end of them and because the groove bottom of the guide groove 8 and the inner cylinder 16 are integrally molded. Therefore, the traversing drum 18 as a whole has an excellent rigidity.
The traversing drums according to the first to third embodiment are each composed of a ceramic burned member. The ceramic burned member has a thermal expansion coefficient different from that of the rotating shaft 2, made of metal. Thus, as an operation time elapses, the heating of the drum motor 4 makes a difference in thermal expansion between the traversing drum and the rotating shaft 2. This may reduce the coupling intensity between the traversing drum and the rotating shaft 2. Thus, as shown in Figure 4, rubber rings 19 are installed on the outer peripheral surface of the bearings 5A, 5B to support the traversing drum via the rubber rings 19. This serves to absorb the difference in thermal expansion caused by the different materials.

Claims

A traversing drum (1; 15; 18) which drives a winding package and which has an endless guide groove (8) formed in an outer peripheral surface of the traversing drum to traverse a yarn, the traverse drum being made of ceramic material,
characterized in that
the drum main body is composed of an inner cylinder (10A, 10B; 16) and an outer cylinder (9; 17) which are integrally molded using ceramic material and which are intermittently connected together using ribs.
A traversing drum (1; 15; 18) according to claim 1,
characterized in that
the ribs connect the inner cylinder (10A, 10B; 16) to the groove bottom of the guide groove (8) of the outer cylinder (9; 17).
A traversing drum (1; 15; 18) according to claim 2,
characterized in that
the inner cylinder (10A, 10B; 16) and the outer cylinder (9; 17) are formed integrally together at one end.