阅读说明：本技术 一种全自动的床垫面布锁边机及床垫面布锁边方法 (Full-automatic mattress surface cloth edge locking machine and mattress surface cloth edge locking method ) 是由 叶健辉 于 2020-07-10 设计创作，主要内容包括：本发明公开了一种全自动的床垫面布锁边机及床垫面布锁边方法,全自动的床垫面布锁边机包括机身、工作台组件、锁边组件、压紧组件和机械手组件,工作台组件包括旋转机构和旋转工作台；锁边组件包括平移机构、摆角机构和锁边机构；压紧组件包括压板传动机构和压板；机械手组件包括机械手传动机构和机械手。本发明的有益效果是：本发明的全自动的床垫面布锁边机能够全自动地进行床垫面布加工,自动加工时,能够加工床垫面布的圆角,能够进行锁边,且能对厚床垫面布进行加工,其加工效果优于人工加工。(The invention discloses a full-automatic mattress surface cloth serging machine and a mattress surface cloth serging method, wherein the full-automatic mattress surface cloth serging machine comprises a machine body, a workbench assembly, a serging assembly, a pressing assembly and a manipulator assembly, wherein the workbench assembly comprises a rotating mechanism and a rotating workbench; the serging assembly comprises a translation mechanism, a swing angle mechanism and a serging mechanism; the pressing assembly comprises a pressing plate transmission mechanism and a pressing plate; the manipulator assembly comprises a manipulator transmission mechanism and a manipulator. The invention has the beneficial effects that: the full-automatic mattress surface cloth serging machine can be used for processing mattress surface cloth in a full-automatic mode, round corners of the mattress surface cloth can be processed during automatic processing, serging can be performed, thick mattress surface cloth can be processed, and the processing effect is superior to manual processing.)

1. The utility model provides a full-automatic mattress face cloth machine of lockstitching a border which characterized in that: the machine comprises a machine body, a workbench assembly, a serging assembly, a pressing assembly and a manipulator assembly, wherein the workbench assembly comprises a rotating mechanism and a rotating workbench; the serging assembly comprises a translation mechanism, a swing angle mechanism and a serging mechanism, the translation mechanism is arranged on the side edge of the machine body, the swing angle mechanism is arranged on the translation mechanism, and the serging mechanism is arranged at the upper end of the swing angle mechanism; the machine body is provided with a pressing plate mounting bracket and a mechanical arm mounting bracket, and the pressing plate mounting bracket and the mechanical arm mounting bracket extend upwards to the upper part of the rotary workbench at the side edge of the machine body; the pressing assembly comprises a pressing plate transmission mechanism and a pressing plate, the pressing plate transmission mechanism is connected with the upper end of the pressing plate mounting support and drives the pressing plate to move up and down, and the pressing plate is opposite to the rotary workbench; the manipulator assembly comprises a manipulator transmission mechanism and a manipulator, the manipulator transmission mechanism is connected with the upper end of the manipulator mounting support, the manipulator transmission mechanism is connected with and drives the manipulator to move up and down and move left and right, and the manipulator is located at the front end of the serging mechanism facing the direction of the machine body.

2. The fully automatic mattress topper overlocking machine of claim 1, wherein: the rotary mechanism comprises a workbench transmission assembly, a first driving motor and a first belt pulley group, the workbench transmission assembly and the first driving motor are mounted on the machine body, the workbench transmission assembly and the first driving motor are connected through the first belt pulley group for transmission, and the rotary workbench is connected to the upper end of the workbench transmission assembly.

3. The fully automatic mattress topper overlocking machine of claim 1, wherein: the translation mechanism comprises a second driving motor, a second belt pulley group, a first linear guide rail and a first sliding table, and the swing angle mechanism comprises a third driving motor and a swing angle transmission assembly; the first linear guide rail is horizontally arranged on the side edge of the machine body, the first sliding table is arranged on the first linear guide rail and can horizontally move along the first linear guide rail, the second driving motor and the first sliding table are connected and driven through the second belt pulley set, the third driving motor is arranged on the first sliding table, the upper end of the third driving motor is connected with the swing angle transmission assembly, and the upper end of the swing angle transmission assembly is connected with the edge locking mechanism.

4. The fully automatic mattress topper overlocking machine of claim 1, wherein: the manipulator transmission mechanism comprises a fourth driving motor, a third belt pulley group, a second linear guide rail, a second sliding table, a driving cylinder, a third linear guide rail and a third sliding table; a second linear guide rail is horizontally arranged at the upper end position of the manipulator mounting bracket, a second sliding table is arranged on the second linear guide rail, a fourth driving motor is connected with the second sliding table through a third pulley group for transmission, a driving cylinder and a third linear guide rail are vertically arranged on the second sliding table in the longitudinal direction, and the third sliding table is arranged on the third linear guide rail; the driving cylinder is connected with and drives the third sliding table to move along the track of the third linear guide rail; and a manipulator is fixedly arranged on the third sliding table.

5. The fully automatic mattress topper overlocking machine of claim 1, wherein: the pressing plate is rotatably connected with the pressing plate transmission mechanism.

6. The fully automatic mattress topper overlocking machine of claim 1, wherein: the axis of the workbench transmission assembly is superposed with the axis of the pressing plate transmission mechanism.

7. A method for lockstitching a border of a mattress surface cloth, which adopts the full-automatic lockstitching machine for the mattress surface cloth as claimed in any one of claims 1 to 6, and the lockstitching step is,

(1) the mattress surface cloth is placed on the rotary workbench, the center of the mattress surface cloth is positioned at the centers of the rotary workbench and the pressing plate, and the pressing plate moves downwards to press and fix the mattress surface cloth;

(2) the swing angle mechanism drives the serging mechanism to rotate clockwise by 45 degrees, and the translation mechanism drives the serging mechanism to enter a first pinhole position of the mattress shell fabric;

(3) the manipulator presses the mattress surface cloth under the drive of the manipulator transmission mechanism, so that the mattress surface cloth cannot rotate, and the serging mechanism rotates 45 degrees anticlockwise;

(4) the rotating mechanism drives the rotating workbench to rotate, the edge locking mechanism locks and sews the mattress surface cloth, and the swing angle mechanism and the translation mechanism adjust the rotating angle and the translation position of the edge locking mechanism according to the rotating position of the mattress surface cloth; the rotating mechanism rotates 360 degrees, and the edge locking mechanism completes the edge locking and sewing of the periphery of the mattress surface cloth 6;

(5) the translation mechanism drives the serging mechanism to return to the initial position.

8. The mattress panel overlock method of claim 7, wherein: in the step (2), the first pinhole position where the edge locking mechanism enters is positioned in the middle of one straight edge of the mattress surface cloth.

9. The mattress panel overlock method of claim 7, wherein: in the step (4), when the edge locking mechanism locks the straight edge of the mattress surface cloth, the direction of the front end of the edge locking mechanism is always vertical to the straight edge of the mattress surface cloth, and when the edge locking mechanism locks the rounded corner of the mattress surface cloth, the front end of the edge locking mechanism always faces the circle center position corresponding to the rounded corner.

Technical Field

The invention relates to the technical field of machining, in particular to a full-automatic mattress shell fabric edge locking machine and a mattress shell fabric edge locking method.

Background

The existing mattress surface cloth serging production process generally comprises the steps that a worker manually operates an industrial serging machine to carry out mattress surface cloth serging operation, great human factors exist when the worker operates the industrial serging machine, the produced products are uneven in quality, the production efficiency is low, and great manpower and material resources are required to be occupied in production and quality inspection. With the development and progress of mechanical automatic production, the manual operation is replaced by the mechanical automatic production, so that the labor cost can be reduced, and the production efficiency can be improved. The automatic mattress surface cloth edge sewing machine consisting of three multi-needle sewing machine heads cannot process the round edges of the mattress surface cloth, cannot automatically lock the edges and can only sew two straight lines; the thick material can not be processed, and the processing effect is not quick and good for manual processing.

Disclosure of Invention

The invention aims to solve the technical problem of the prior art and provides a full-automatic mattress shell fabric serging machine and a mattress shell fabric serging method.

In order to solve the technical problems, the technical scheme adopted by the invention is as follows: a full-automatic mattress cover fabric serging machine comprises a machine body, a workbench assembly, serging assemblies, a pressing assembly and a manipulator assembly, wherein the workbench assembly comprises a rotating mechanism and a rotating workbench; the serging assembly comprises a translation mechanism, a swing angle mechanism and a serging mechanism, the translation mechanism is arranged on the side edge of the machine body, the swing angle mechanism is arranged on the translation mechanism, and the serging mechanism is arranged at the upper end of the swing angle mechanism; the machine body is provided with a pressing plate mounting bracket and a mechanical arm mounting bracket, and the pressing plate mounting bracket and the mechanical arm mounting bracket extend upwards to the upper part of the rotary workbench at the side edge of the machine body; the pressing assembly comprises a pressing plate transmission mechanism and a pressing plate, the pressing plate transmission mechanism is connected with the upper end of the pressing plate mounting support and drives the pressing plate to move up and down, and the pressing plate is opposite to the rotary workbench; the manipulator assembly comprises a manipulator transmission mechanism and a manipulator, the manipulator transmission mechanism is connected with the upper end of the manipulator mounting support, the manipulator transmission mechanism is connected with and drives the manipulator to move up and down and move left and right, and the manipulator is located at the front end of the serging mechanism facing the direction of the machine body.

Among the above-mentioned technical scheme, rotary mechanism includes workstation transmission assembly, first driving motor and first pulley group, and workstation transmission assembly and first driving motor install on the fuselage, connect the transmission through first pulley group between workstation transmission assembly and the first driving motor, and rotary table connects the upper end at workstation transmission assembly.

In the above technical scheme, the translation mechanism includes a second driving motor, a second pulley set, a first linear guide rail, and a first sliding table, and the swing angle mechanism includes a third driving motor and a swing angle transmission assembly; the first linear guide rail is horizontally arranged on the side edge of the machine body, the first sliding table is arranged on the first linear guide rail and can horizontally move along the first linear guide rail, the second driving motor and the first sliding table are connected and driven through the second belt pulley set, the third driving motor is arranged on the first sliding table, the upper end of the third driving motor is connected with the swing angle transmission assembly, and the upper end of the swing angle transmission assembly is connected with the edge locking mechanism.

In the above technical scheme, the manipulator transmission mechanism includes a fourth driving motor, a third pulley group, a second linear guide rail, a second sliding table, a driving cylinder, a third linear guide rail, and a third sliding table; a second linear guide rail is horizontally arranged at the upper end position of the manipulator mounting bracket, a second sliding table is arranged on the second linear guide rail, a fourth driving motor is connected with the second sliding table through a third pulley group for transmission, a driving cylinder and a third linear guide rail are vertically arranged on the second sliding table in the longitudinal direction, and the third sliding table is arranged on the third linear guide rail; the driving cylinder is connected with and drives the third sliding table to move along the track of the third linear guide rail; and a manipulator is fixedly arranged on the third sliding table.

In the technical scheme, the pressing plate is rotatably connected with the pressing plate transmission mechanism.

In the technical scheme, the axis of the workbench transmission assembly is superposed with the axis of the pressing plate transmission mechanism.

A mattress surface cloth edge locking method, which adopts the full-automatic mattress surface cloth edge locking machine in the technical proposal and comprises the steps of edge locking,

(1) the mattress surface cloth is placed on the rotary workbench, the center of the mattress surface cloth is positioned at the centers of the rotary workbench and the pressing plate, and the pressing plate moves downwards to press and fix the mattress surface cloth;

(2) the swing angle mechanism drives the serging mechanism to rotate clockwise by 45 degrees, and the translation mechanism drives the serging mechanism to enter a first pinhole position of the mattress shell fabric;

(3) the manipulator presses the mattress surface cloth under the drive of the manipulator transmission mechanism, so that the mattress surface cloth cannot rotate, and the serging mechanism rotates 45 degrees anticlockwise;

(4) the rotating mechanism drives the rotating workbench to rotate, the edge locking mechanism locks and sews the mattress surface cloth, and the swing angle mechanism and the translation mechanism adjust the rotating angle and the translation position of the edge locking mechanism according to the rotating position of the mattress surface cloth; the rotating mechanism rotates 360 degrees, and the edge locking mechanism completes the edge locking and sewing of the periphery of the mattress surface cloth 6;

(5) the translation mechanism drives the serging mechanism to return to the initial position.

In the step (2) of the method, the first pinhole position entered by the edge locking mechanism is positioned in the middle of one straight edge of the mattress surface cloth.

In the step (4) of the method, when the edge locking mechanism locks the straight edge of the mattress surface cloth, the direction of the front end of the edge locking mechanism is always vertical to the straight edge of the mattress surface cloth, and when the edge locking mechanism locks the rounded edge of the mattress surface cloth, the front end of the edge locking mechanism always faces the circle center position corresponding to the rounded edge.

The invention has the beneficial effects that: the full-automatic mattress surface cloth serging machine can be used for processing mattress surface cloth in a full-automatic mode, round corners of the mattress surface cloth can be processed during automatic processing, serging can be performed, thick mattress surface cloth can be processed, and the processing effect is superior to manual processing.

Drawings

Fig. 1 is a front view of the overall structure of the present invention.

Fig. 2 is a schematic top view of the overall structure of the present invention.

Fig. 3 is a schematic diagram of the first operating state of the present invention.

Fig. 4 is a schematic diagram of the second operating state of the present invention.

Fig. 5 is a schematic diagram of the third operating state of the present invention.

Fig. 6 is a schematic diagram of the operating state four of the present invention.

Fig. 7 is a schematic diagram of the operating state five of the present invention.

Fig. 8 is a schematic diagram of the operating state six of the present invention.

Fig. 9 is a schematic illustration of the operating state seven of the present invention.

Fig. 10 is a schematic diagram of the operating state eight of the present invention.

Fig. 11 is a schematic diagram of the operating state nine of the present invention.

Reference numerals

1. A body; 11. a pressure plate mounting bracket; 12. a manipulator mounting bracket; 2. a table assembly; 21. a table drive assembly; 22. a first drive motor; 23. a first pulley set; 24. rotating the working table; 3. a lockstitch component; 31. a second drive motor; 32. a second pulley set; 33. a first linear guide rail; 34. a first sliding table; 35. a third drive motor; 36. a swing angle transmission assembly; 37. a serging mechanism; 4. a compression assembly; 41. a pressure plate transmission mechanism; 42. pressing a plate; 5. a manipulator assembly; 51. a fourth drive motor; 52. a third pulley set; 53. a second linear guide; 54. a second sliding table; 55. a driving cylinder; 56. a third linear guide rail; 57. a third sliding table; 58. a manipulator; 6. mattress surface cloth.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings.

As shown in fig. 1-2, a fully automatic mattress cover fabric 6 overlocking machine, which mainly comprises a machine body 1, a workbench assembly 2, an overlocking assembly 3, a pressing assembly 4 and a manipulator assembly 5. The machine body 1 is used as an installation main body of a full-automatic mattress surface cloth 6 serging machine and used for fastening and installing the workbench assembly 2, the serging assembly 3, the pressing assembly 4 and the manipulator assembly 5.

The workbench component 2 is mainly used for placing and rotating mattress surface cloth 6 to be subjected to edge locking, the workbench component 2 comprises a rotating mechanism and a rotating workbench 24, the rotating mechanism comprises a workbench transmission assembly 21, a first driving motor 22 and a first belt pulley group 23, the workbench transmission assembly 21 and the first driving motor 22 are fixedly installed on the upper surface of the machine body 1, the axis of the workbench transmission assembly 21 is perpendicular to the upper surface of the machine body 1, the connection transmission between the workbench transmission assembly 21 and the first driving motor 22 is realized through a first belt pulley, the rotating workbench 24 is connected to the upper end of the workbench transmission assembly 21, and the rotating workbench 24 is parallel to the upper surface of the machine body 1. When the mattress is used, the mattress surface cloth 6 is placed on the rotary workbench 24, the first driving motor 22 provides rotary power, and the rotary workbench 24 rotates through the transmission of the first belt pulley set 23 and the workbench transmission assembly 21. In practical applications, the worktable assembly 2 is not limited to use the worktable transmission assembly 21, the first driving motor 22 and the first pulley set 23 as the rotating mechanism to implement the installation and rotation functions of the rotating worktable 24, and other rotating mechanisms capable of implementing the same functions may be used instead.

The serging component 3 is mainly used for serging and sewing the edge of the mattress surface fabric 6, the serging component 3 comprises a translation mechanism, a swing angle mechanism and a serging mechanism 37, the translation mechanism comprises a second driving motor 31, a second belt pulley group 32, a first linear guide rail 33 and a first sliding table 34, and the swing angle mechanism comprises a third driving motor 35 and a swing angle transmission assembly 36. The first linear guide rail 33 is horizontally arranged at the right end of the machine body 1, the track direction of the first linear guide rail 33 is the left-right moving direction, namely the direction that the level is close to or far away from the mattress surface cloth 6, the track of the first linear guide rail 33 is provided with the first sliding table 34, the first sliding table 34 can move along the track direction of the first linear guide rail 33, the first sliding table 34 and the second driving motor 31 are connected and driven through the second pulley set 32, and the second driving motor 31 is used as a power source for the first sliding table 34 to move on the first linear track. A third driving motor 35 is fixedly mounted on the first sliding table 34, the upper end of the third driving motor 35 is connected with a swing angle transmission assembly 36, the axis of the swing angle transmission assembly 36 is perpendicular to the upper surface of the machine body 1, and the upper end of the swing angle transmission assembly 36 is connected with a serging mechanism 37. The serging mechanism 37 realizes the rotation motion along the axis of the swing angle transmission assembly 36 through the swing angle mechanism, and the third driving motor 35 can rotate in the forward direction and the reverse direction to drive the serging mechanism 37 to rotate in the forward direction and the reverse direction. The overlock mechanism 37 achieves movement of itself in the horizontal direction toward or away from the mattress topper 6 by a translation mechanism. In practical applications, the overlock stitching component 3 is not limited to use the second driving motor 31, the second pulley set 32, the first linear guide rail 33 and the first sliding table 34 as the translation mechanism to realize the movement of the overlock stitching mechanism 37 in the horizontal direction, nor is the overlock stitching component 3 limited to use the third driving motor 35 and the swing angle transmission assembly 36 as the swing angle mechanism to realize the longitudinal rotation movement of the overlock stitching mechanism 37, but other swing angle mechanisms capable of realizing the same function may be used instead.

The hold-down assembly 4 is mainly used for preventing the mattress surface cloth 6 from moving when being subjected to edge locking, so that the edge locking deviates and even the mattress surface cloth 6 is separated. The pressing component 4 comprises a pressing plate transmission mechanism 41 and a pressing plate 42, a pressing plate mounting support 11 is arranged on the side edge of the machine body 1, the pressing plate mounting support 11 extends upwards to the rotary workbench 24 on the side edge of the machine body 1, the pressing plate transmission mechanism 41 is tightly mounted on the pressing plate mounting support 11, the pressing plate transmission mechanism 41 is located right above the rotary workbench 24, the pressing plate 42 is connected and mounted at the lower end of the pressing plate transmission mechanism 41, the pressing plate 42 is parallel to the rotary workbench 24, the pressing plate transmission mechanism 41 can drive the pressing plate 42 to move up and down, the pressing plate 42 can move downwards and can press the mattress surface cloth 6 together with the rotary workbench 24, and the mattress surface cloth 6 is prevented from moving horizontally and vertically. The pressing plate 42 is rotatably connected with the pressing plate transmission mechanism 41, and when the rotary worktable 24 drives the mattress surface cloth 6 to rotate, the pressing plate 42 can rotate along with the mattress surface cloth 6. In order to ensure the balance of the acting force of the rotary worktable 24 and the pressing plate 42 on the mattress panel, the axis of the pressing plate transmission mechanism 41 is superposed with the axis of the worktable transmission assembly 21.

The robot assembly 5 is primarily used to press the mattress panel 6 when the overlock mechanism 37 is first entered into the mattress panel 6 and is required to be pivoted. The manipulator assembly 5 is installed above the machine body 1 and the rotary workbench 24, the manipulator assembly 5 comprises a manipulator 58 and a manipulator transmission mechanism for driving the manipulator 58 to move up, down, left and right, and the manipulator transmission mechanism comprises a fourth driving motor 51, a third belt pulley group 52, a second linear guide rail 53, a second sliding table 54, a driving cylinder 55, a third linear guide rail 56 and a third sliding table 57. A manipulator mounting bracket 12 is arranged on the side edge of the machine body 1, the manipulator mounting bracket 12 extends upwards to the rotary workbench 24 on the side edge of the machine body 1, a second linear guide rail 53 is fixedly mounted at the upper end position of the manipulator mounting bracket 12, a track of the second linear guide rail 53 is horizontally arranged, a second sliding table 54 is mounted on the second linear guide rail 53, a fourth driving motor 51 is mounted at the side end of the second linear guide rail 53, and the fourth driving motor 51 and the second sliding table 54 are connected and driven through a third pulley group 52; the driving air cylinder 55 and the third linear guide rail 56 are installed on the second sliding table 54, the track of the third linear guide rail 56 is vertically arranged, the third sliding table 57 is installed on the third linear guide rail 56, and the driving air cylinder 55 is connected with and drives the third sliding table 57 to move along the track of the third linear guide rail 56; a manipulator 58 is fixedly mounted on the third slide table 57, and the manipulator 58 is located at the front end of the overlock mechanism 37 facing the direction of the body 1. According to the size requirements of different mattress shell fabrics 6, the position of the manipulator 58 for pressing the mattress shell fabrics 6 is adjusted up and down, left and right through a manipulator transmission mechanism. In practical applications, the manipulator transmission mechanism is not limited to the fourth driving motor 51, the third pulley group 52, the second linear guide 53, the second sliding table 54, the driving cylinder 55, the third linear guide 56, and the third sliding table 57 for moving the manipulator 58 up and down and left and right, and other manipulator transmission mechanisms capable of achieving the same function may be used instead.

When the full-automatic mattress surface cloth 6 serging machine is used, the mattress surface cloth 6 is placed on the rotary workbench 24, the center of the mattress surface cloth 6 is located at the axis positions of the workbench transmission assembly 21 and the pressing plate transmission mechanism 41, the pressing plate 42 presses the mattress surface cloth 6 on the rotary workbench 24, the serging mechanism 37 moves to the edge of the mattress surface cloth 6, the rotary workbench 24 rotates, the serging mechanism 37 performs serging and sewing at the same time, and the serging mechanism 37 adjusts the distance and the angle between the serging mechanism 37 and the mattress surface cloth through the translation mechanism and the swing angle mechanism.

Referring to fig. 3 to 11, the overlocking method of the fully automatic overlocking machine for the mattress surface cloth 6 includes the following steps:

(1) the mattress surface cloth 6 is placed on the rotary workbench 24, the center of the mattress surface cloth 6 is positioned at the center of the rotary workbench 24 and the pressing plate 42, and the pressing plate 42 moves downwards to press and fix the mattress surface cloth 6 (figure 3);

(2) the swing angle mechanism drives the serging mechanism 37 to rotate clockwise by 45 degrees, and the translation mechanism drives the serging mechanism 37 to move along the first linear guide rail 33 and enter a first pinhole position of the mattress surface fabric 6 (figure 4-5);

(3) the manipulator 58 is driven by the manipulator transmission mechanism to press the mattress surface cloth 6, so that the mattress surface cloth 6 cannot rotate, and the overlock mechanism 37 rotates 45 degrees counterclockwise (figure 6);

(4) the rotating mechanism drives the rotating workbench 24 to rotate, the overlock mechanism 37 overlocks and sews the mattress surface cloth 6, and the swing angle mechanism and the translation mechanism adjust the rotating angle and the translation position of the overlock mechanism 37 according to the rotating position of the mattress surface cloth 6; the rotating mechanism rotates 360 degrees, the serging mechanism 37 completes serging and sewing on the periphery of the mattress surface cloth 6 (fig. 7-10);

(5) the translation mechanism moves the overlock mechanism 37 along the first linear guide 33 and retracts to the initial position (fig. 11).

In step (2) of the above-mentioned overlock method, the first pinhole position where the overlock mechanism 37 enters is located at the middle position of one straight edge of the mattress top fabric 6.

In the step (4) of the above-mentioned overlock method, when the overlock mechanism 37 overlocks the straight edge of the mattress surface cloth 6, the head direction of the overlock mechanism 37 is always perpendicular to the straight edge of the mattress surface cloth 6, and when the overlock mechanism 37 overlocks the rounded corner of the mattress surface cloth 6, the head direction of the overlock mechanism 37 is always towards the position of the center of the circle corresponding to the rounded corner.

The above-mentioned overlocking method is explained by taking the mattress top sheet 6 of a rectangular parallelepiped structure as an example of the overlocking operation, and the overlocking method is also applicable to overlocking and sewing the mattress top sheet 6 of another shape such as a cylindrical shape.

The above examples are intended to illustrate rather than to limit the invention, and all equivalent changes and modifications made by the methods described in the claims of the present invention are intended to be included within the scope of the present invention.