JP2006297664A - Cylindrical rubber having taper part and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a cylindrical rubber having a taper part capable of performing desired control with respect to the cylindrical rubber having the taper part, which is formed by winding an extruded rubber around a mandrel, so as to precisely make the thickness of the cylindrical rubber constant over its whole length or to change the thickness of the cylindrical rubber so as to make its one end thick and the other end thin. <P>SOLUTION: In the manufacturing method of the cylindrical rubber having the taper partper, in the molding process of spirally winding the belt like rubber 11 extruded in a predetermined cross-sectional shape from an extruder 3 around the mandrel 1 having a taper part IT changing its outer peripheral length as moved in the direction of the axis P of the mandrel, the mandrel 1 is rotated, and the extruder 3 and the mandrel 1 are relatively moved in the direction of the rotary axis P of the mandrel 1 while at least either one of the extrusion speed of the rubber due to the extruder 3, the rotatory speed Vr of the mandrel 1 and the relative moving speed Vi of the extruder 3 and the mandrel 1 is controlled variably. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a cylindrical rubber having a tapered portion, and a cylindrical rubber having a tapered portion created by the manufacturing method.

  The cylindrical rubber having the tapered portion is often used as a basic component in a rubber product or high-pressure hose that requires high-pressure reinforcement. For example, it is used as a fiber-reinforced rubber hose that becomes a pumping tube of a squeeze pump by wrapping a rubber-coated cord around the outer periphery of the rubber-coated cord and vulcanizing it. Moreover, it may be used as a base material for a docking hose.

  As a conventional method for molding a cylindrical rubber having a tapered portion, (1) a method of extruding rubber into a tube shape and inserting it into a mandrel, (2) a method of molding by crosshead extrusion, and (3) a cylindrical rubber sheet There are three types of methods: wrapping around and molding. The manufacturing method of (1) is known as disclosed in Patent Document 1, the manufacturing method of (2) is known as disclosed in Patent Document 2, and the manufacturing method of (3) is patented. The one disclosed in Document 3 is known.

  In the manufacturing method of the conventional example (1), the rubber thickness of the inner diameter can be increased / decreased by extruding the tube, but it is impossible to mold by changing both the inner diameter and the outer diameter. The manufacturing method of the conventional example (2) is the same as the manufacturing method of (1), and it cannot be molded by changing both the inner and outer diameters. In the manufacturing method of the conventional example (3), a truncated cone shape can be formed by changing the sheet shape according to the shape of the cylindrical body around which the rubber is wound. However, the maximum thickness of the rubber molded in a single layer is about 3 mm, and a truncated cone-shaped cylinder having a thickness of about 20 mm cannot be molded.

In addition, it is conceivable that a thin rubber thickness is laminated by the manufacturing method of the conventional example (3) to make it thick, but this method requires a lot of time and cost for the lamination process, and several Since the work of winding a long rubber sheet of m is difficult, it is still not a realistic method. As described above, in the manufacturing method according to the prior art, it is difficult to produce a cylindrical rubber having a tapered portion such as a truncated cone having a certain thickness.
Japanese Patent Laid-Open No. 08-047961 JP 2000-280322 A JP-A-10-264265

  An object of the present invention is to provide a cylindrical rubber having a taper portion formed by extruding a predetermined shape rubber and winding it around a truncated cone (mandrel) with a constant thickness over the entire length. A method of manufacturing a cylindrical rubber having a tapered portion that can be controlled to a desired state, such as changing the thickness so that the thickness at one end is large and the thickness at the other end is thin, and the taper created thereby It is in the point which provides the cylindrical rubber which has a part.

  According to the first aspect of the present invention, in the method for producing a cylindrical rubber having a tapered portion, the outer peripheral length of the belt-like rubber 11 extruded from the extruder 3 with a predetermined cross-sectional shape moves in the direction of the axis P. In performing the forming process of spirally winding around the mandrel 1 having the taper portion 1T in which the mandrel changes, the mandrel 1 is rotated, and the extruder 3 and the mandrel 1 are moved in the direction of the rotation axis P of the mandrel 1 In addition to the relative movement, at least one of the rubber extrusion speed Vg by the extruder 3, the rotation speed Vr of the mandrel 1, and the relative movement speed Vi is variably controlled. is there.

  According to a second aspect of the present invention, in the method for producing a cylindrical rubber having a tapered portion according to the first aspect, in the molding step, the relative moving speed Vi and the rotational speed Vr of the mandrel 1 are kept constant. However, the extrusion speed Vg is variably controlled.

  According to a third aspect of the present invention, in the method for producing a cylindrical rubber having a tapered portion according to the first aspect, in the molding step, the rotation speed Vr and the extrusion speed Vg of the mandrel 1 are maintained constant. The relative movement speed Vi is variably controlled.

  According to a fourth aspect of the present invention, in the method for producing a cylindrical rubber having a tapered portion according to the first aspect, in the molding step, the relative movement speed Vi and the extrusion speed Vg are maintained constant. The rotational speed Vr is variably controlled.

  According to a fifth aspect of the present invention, in the method for producing a cylindrical rubber having a tapered portion according to any one of the first to fourth aspects, the rubber extruded from the extruder 3 is fed through the gear pump 4 to the mandrel. 1, and the extrusion speed Vg of the extruder 3 is variably controlled in synchronization with the discharge speed Ve of the gear pump 4.

  The invention according to claim 6 is the method for producing a cylindrical rubber having a tapered portion according to any one of claims 1 to 5, wherein the rubber wound around the mandrel 1 by the molding step is used as the mandrel 1. It presses in the inner diameter side direction.

  The invention according to claim 7 is characterized in that the cylindrical rubber having the tapered portion is produced by the method for producing the cylindrical rubber having the tapered portion according to any one of claims 1 to 6. It is what.

  According to the first aspect of the present invention, in producing a cylindrical rubber having a tapered portion by winding a belt-like rubber extruded from an extruder with a predetermined cross-sectional shape around a mandrel having a tapered portion, Since one or more of the extrusion speed, the rotation speed of the mandrel, and the relative movement speed of the extruder and the mandrel are variably controlled, the thickness of the rubber wound around the mandrel is related to the position of the mandrel in the axial direction. It becomes possible to variably set in any way. As a result, a cylindrical rubber having a tapered portion formed by extruding a predetermined shape rubber and winding it around a truncated cone-shaped cylinder (mandrel), with a constant thickness over the entire length, It is possible to provide a method for producing a cylindrical rubber having a tapered portion that can be controlled to a desired state such that the thickness is changed so that the thickness of the other end is reduced and the thickness of the other end is reduced.

  As control means in this case, as in claim 2, the relative movement speed and the rotation speed of the mandrel are kept constant, and only the rubber extrusion speed is variably controlled. A means for variably controlling only the relative movement speed while maintaining the speed and the rotation speed of the mandrel. As in claim 4, the relative movement speed and the extrusion speed of the rubber are maintained constant and only the rotation speed of the mandrel is controlled. Means for variably controlling, etc. are possible.

  According to the invention of claim 5, since it is a means for supplying the rubber extruded from the extruder to the die using the gear pump which is a constant supply pump, the accuracy of the amount of rubber supplied by the extruder per unit time is further improved. To provide a method for producing a cylindrical rubber having a tapered portion that can be made high, thereby improving variation in thickness and dimensional error of the cylindrical rubber having a tapered portion, and improving accuracy as a product. Can do.

  According to the invention of claim 6, the belt-like rubber wound around the mandrel is positively cured by pressing toward the inner diameter side, thereby causing various factors such as a molding time difference and a decrease in the rubber temperature. As a result, the rubber thickness is prevented from varying depending on the part, and a cylindrical rubber having a taper portion with higher accuracy can be produced.

  According to the invention of claim 7, the taper portion created by extruding a predetermined shape of rubber and winding it around a truncated cone (mandrel) by the above-described method for producing a cylindrical rubber having a taper portion. The cylindrical rubber that has a constant thickness over the entire length, or that can be controlled to the desired state, such as changing the thickness so that the thickness at one end is thick and the other end is thin. Can be provided as.

  Hereinafter, a method for producing a cylindrical rubber having a tapered portion according to the present invention and an embodiment of the cylindrical rubber having a tapered portion will be described with reference to the drawings. FIG. 1 is an original view showing an apparatus for producing a tubular rubber having a tapered portion, FIGS. 2 and 3 are views showing production examples 1 and 2 of the tubular rubber having a tapered portion, and FIGS. It is a comparison table | surface which shows the various characteristics of each and the thing by a conventional manufacturing method.

[Example 1]
FIG. 1 shows a principle diagram of a cylindrical rubber manufacturing apparatus A having a tapered portion. The manufacturing apparatus A includes a mandrel 1 that is a cylindrical body having a tapered shape over its entire length, a rotating mechanism 2 that drives and rotates a mandrel 1 that is rotatable about an axis P, a rubber extruder 3, and an extruder 3. A gear pump 4 that feeds the rubber extruded from the die, a die 10 for molding the rubber discharged from the gear pump 4 into a predetermined shape, and a moving mechanism 5 that can move the mandrel 1 together with the rotating mechanism 2 in the direction of the axis P. And is configured.

  The mandrel 1 is formed in a cylindrical body having a small-diameter side end 1a having a small diameter, a large-diameter side end 1b having a larger diameter, and a tapered portion 1T whose outer peripheral length changes as it moves in the axis P direction. ing. As shown in FIG. 1, the shape of the mandrel 1 is a truncated cone shape or a small-diameter cylindrical portion having a diameter of the small-diameter side end 1a and a large-diameter side end 1b. It may have a slightly large-diameter cylindrical portion having a diameter and a tapered portion 1T straddling both, and other shapes are also possible.

  The rotation mechanism 2 is configured so that the mandrel 1 can be driven and rotated at an arbitrary speed in the forward and reverse directions using, for example, a first electric motor or the like. The moving mechanism 5 includes, for example, a pair of rails 7 and 7 that support a bed 6 that rotatably supports the mandrel 1 so as to be parallelly movable in the direction of the axis P, a screw shaft 8 that is screwed to the bed 6, and a screw And a second electric motor 9 for driving and rotating the shaft 8, and the bed 6, that is, the mandrel 1, is configured to be movable in parallel in the direction of arrow B or B by forward and reverse driving of the second electric motor 9. That is, the extruder 3 and the mandrel 1 are relatively moved in the direction of the rotation axis P of the mandrel 1 with the moving speed Vi by the moving mechanism 5.

  The extruder 3, gear pump 4, first and second electric motors 2, 9 are connected to the control device 12, rubber extrusion speed (extrusion amount per unit time) Vg by the extruder 3, and rubber extrusion by the gear pump 4. The discharge speed (feed amount per unit time) Ve, the rotation direction and rotation speed (number of rotations per unit time) Vr of the mandrel 1, and the translational speed Vi of the mandrel 1 (bed 6) can be arbitrarily controlled. Has been. Then, the extrusion speed control means 12A included in the control device 12 keeps the movement speed Vi of the mandrel 1 and the rotation speed Vr of the mandrel 1 in the direction of the arrow C, while maintaining the rubber extrusion speed Vg by the extruder 3 to the gear pump 4. , And the extrusion speed Vg by the extruder 3 and the discharge speed Ve by the gear pump 4 are variably controlled. As a result, it is possible to wind the belt-shaped rubber, that is, the rubber band 11, discharged from the gear pump 4 with a uniform thickness and a constant winding angle θ around the mandrel 1.

  In this case, by disposing the gear pump 4 between the extruder 3 and the die 10, the supply amount per unit time of a rubber band (belt-like rubber) 11 continuously extruded in a predetermined shape from the die 10. The accuracy can be further increased and stable supply can be achieved. Further, when the rubber band 11 is wound around the mandrel 1, the rubber band 11 wound with a constant pressure is pressed using a stitcher, or a synthetic resin tape (polyethylene tape) is tracked following the winding of the rubber band 11. Or the like) (by pressing the rubber band 11 wound around the mandrel 1 in the direction of the inner diameter side of the mandrel 1), a more accurate frustoconical cylindrical rubber (cylindrical rubber having a tapered portion) ) 13 can be created.

  Next, the preparation point of the truncated cone-shaped cylindrical rubber (an example of the cylindrical rubber having a tapered portion) by the manufacturing apparatus A will be described. First, the mandrel 1 is moved in the direction indicated by the arrow B, for example, so that the small diameter side end 1a is set in a start state positioned in front of the gear pump 4. Then, the mandrel 1 is driven and rotated in the direction of the arrow C, and the bed 6 is translated in the direction of the arrow B, and a rubber band 11 of a predetermined shape fed out from the gear pump 4 is wound around the mandrel 1 from the small-diameter side end 1a.

  At this time, due to the function of the extrusion speed control means 12A, the screw rotation speed of the extruder 3 and the rotation speed of the gear pump 4 are kept constant while the parallel movement speed Vi of the mandrel 1 in the direction of arrow B and the rotation speed Vr of the direction of arrow C are constant. That is, since the extrusion speed Vg and the discharge speed Ve are controlled so as to increase as the winding position of the rubber band 11 around the mandrel 1 shifts to the large diameter side, the extrusion speed Vg and the discharge speed Ve are extruded from the die 10 and wound around the mandrel 1. The frustoconical cylindrical rubber 13 made of the rubber band 11 can be formed with a uniform thickness.

  That is, in the manufacturing method of the cylindrical rubber having the tapered portion by the manufacturing apparatus A, the outer peripheral length changes as the belt-shaped rubber 11 extruded from the extruder 3 with a predetermined cross-sectional shape moves in the axis P direction. In performing the forming step of spirally winding the mandrel 1 having the tapered portion 1A, the mandrel 1 is rotated, and the extruder 3 and the mandrel 1 are relatively moved in the direction of the rotation axis P of the mandrel 1, and the extrusion is performed. It is characterized by variably controlling at least one of the rubber extrusion speed Vg by the machine 3, the rotation speed Vr of the mandrel 1, and the relative movement speed Vi. In Example 1, in the molding process, the extrusion speed Vg and the discharge speed Ve are variably controlled while the relative movement speed Vi and the rotation speed Vr of the mandrel 1 are kept constant. Next, production examples 1 and 2 of the truncated cone-shaped rubber 13 will be described.

[Example 1]
The frustoconical cylindrical rubber 13 of Creation Example 1 is created under the following conditions. That is, the rubber band 11 extruded from the die 10 has a cross-sectional shape having a width of 70 mm and a thickness of 2 mm by the action of the extrusion speed control means 12A. When this is wound around the mandrel 1 where the parallel movement speed is 2.8 mm / s and the rotation speed is 23 rpm, the rotation speed of the gear pump 4 is 130 rpm at the start of winding (small diameter side end). Is variably controlled to 210 rpm at the end of winding (large diameter side end). Naturally, the extrusion speed Vg of the extruder 3 is controlled to increase or decrease in synchronization with the discharge speed Ve of the gear pump 4. That is, when the rubber extruded from the extruder 3 is wound around the mandrel 1 via the gear pump 4, both the speeds Vg and Ve are variable while the extrusion speed Vg of the extruder 3 is synchronized with the discharge speed Ve of the gear pump 4. To control.

  As a result, as shown in FIG. 2, a truncated cone-shaped cylindrical rubber 13 having a total length of 3000 mm, a large-diameter outer diameter of 122 mm and a thickness of 7.0 mm, and a small-diameter outer diameter of 104 mm and a thickness of 5.5 mm. Created. The frustoconical cylindrical rubber 13 according to this production example 1 is suitable for an inner rubber cylinder of a fiber reinforced rubber hose used as a docking hose in a cement feeder (pump car), for example. As a reference, FIG. 4 shows a comparison of characteristics between the truncated cone-shaped cylindrical rubber 13 according to Preparation Example 1 and the truncated cone-shaped cylindrical rubber 13 produced by the manufacturing method of inserting the rubber tube extrudate into the mandrel [conventional method of (1) above]. Write a table.

[Example 2]
The frustoconical cylindrical rubber 13 of creation example 2 is created under the following conditions. That is, by the function of the extrusion speed control means 12A, the rubber band 11 having a width of 70 mm and a thickness of 2 mm extruded from the die 10 is both constant at a parallel movement speed of 2.8 mm / s and a rotation speed of 23 rpm. When winding around the mandrel 1 maintained at, the rotation speed of the gear pump 4 is controlled from 430 rpm at the start of winding (small-diameter side end) to 530 rpm at the end of winding (large-diameter side end). However, the mandrel 1 (see FIG. 1) has a total length of more than 3300 mm, a diameter on the small-diameter side end of 116 mm, and a diameter on the large-diameter side end of 136 mm.

  As a result, as shown in FIG. 3, the truncated cone-shaped cylindrical rubber 13 having a total length of 3300 mm, an inner diameter (116 + α) mm at the small-diameter side end, and an inner diameter (136-α) mm at the large-diameter side end has a constant rubber thickness of 18 mm. Can be created as The frustoconical cylindrical rubber 13 according to the production example 2 is suitable for an inner rubber cylinder of a fiber reinforced rubber hose used as a pumping tube in a cement feeder (pump car), for example. For reference to the tip hose, FIG. 5 shows a comparative table of characteristics between the truncated cone-shaped cylindrical rubber 13 according to Preparation Example 2 and the truncated cone-shaped cylindrical rubber according to the conventional examples (1) to (3). As can be seen from FIGS. 4 and 5, the method of manufacturing the truncated cone-shaped cylindrical rubber 13 according to the present invention is superior in all aspects as compared with the prior art, and no special technique is required at the time of molding. There is an advantage that no subsequent processes such as finishing are required. In addition, compared with the prior art, there are many advantages such as a significant reduction in material loss, cost reduction by shortening the time, and diversification of processable rubber.

  As described above, according to the method for producing a cylindrical rubber having a tapered portion of the present invention, the following actions and effects can be obtained. 1. By continuously extruding rubber having a predetermined cross-sectional shape and winding it around a mandrel, the cylindrical rubber having a tapered portion is made constant in thickness with high thickness accuracy, or has a thickness on one end side. There is an advantage that it is possible to provide a small size and a large thickness on the other end side.

  2. Using a relatively inexpensive facility (manufacturing apparatus A), not only can the cylindrical rubber 13 having a tapered portion, which has been difficult to be molded, be molded, but also the rubber extrusion speed Vg by the extruder 3 can be increased. By controlling the rotation speed Vr and the movement speed Vi of the mandrel 1, the cylindrical rubber 13 having a tapered portion can be automatically molded. As a result, labor costs and administrative costs can be reduced. In addition, by changing the shape of the mandrel 1, it is possible to mold the cylindrical rubber 13 having tapered portions having various shapes and sizes.

  3. According to the method for producing a cylindrical rubber having a tapered portion according to the present invention, a desired “cylindrical rubber 13 having a tapered portion” can be obtained only by operating the production apparatus A. Therefore, a rubber sheet is prepared in advance. Such a preliminary process is unnecessary, and there is an advantage that advanced technology is not required.

  4). When the rubber extruded from the die 10 is wound around the mandrel 1, it is not limited to molding in which the thickness of the cylindrical rubber 13 having the tapered portion increases or decreases as it advances in the direction of the axis P. For example, rubber Cylindrical rubber having a tapered portion in which the rubber thickness is repeatedly increased or decreased in the direction of the axis P by repeatedly increasing or decreasing the extrusion speed Vg of the cylinder or by repeatedly increasing or decreasing the rotational speed Vr of the mandrel 1 or other specially-shaped cylinders Rubber molding is also possible.

[Example 2]
The manufacturing method according to Example 2 is a method of variably controlling the relative movement speed Vi of the mandrel 1 while keeping the rotation speed Vr of the mandrel 1 and the rubber extrusion speed Vg by the extruder 3 constant in the molding step. That is, in the control apparatus 12 shown in FIG. 1, it manufactures using the moving speed control means 12B instead of the extrusion speed control means 12A.

  For example, when the winding of the rubber band 11 is started from the small-diameter side end, if the moving speed Vi of the mandrel 1 in the direction of arrow A (see FIG. 1) is controlled so as to gradually decrease, the large-diameter side end is reached. Accordingly, the truncated cone-shaped cylindrical rubber 13 (see FIG. 2) whose thickness increases according to the above and the truncated cone-shaped cylindrical rubber 13 (see FIG. 3) having a constant thickness can be created. Further, if the moving speed Vi is set so as to gradually decrease, remain unchanged, or increase, it is possible to create a truncated cone-shaped cylindrical rubber whose thickness decreases as it goes to the large diameter side end.

Example 3
The manufacturing method according to Example 3 is a method of variably controlling the rotation speed Vr of the mandrel 1 while keeping the relative movement speed Vi of the mandrel 1 and the rubber extrusion speed Vg by the extruder 3 constant in the molding process. . That is, in the control apparatus 12 shown in FIG. 1, it manufactures using the rotational speed control means 12C instead of the extrusion speed control means 12A.

  For example, when the winding of the rubber band 11 is started from the end on the small diameter side, the rotation speed Vr of the mandrel 1 in the direction of the arrow C (see FIG. 1) decreases as the amount of movement of the mandrel 1 in the direction of arrow A increases. If it controls so that it may become, the truncated cone-shaped cylindrical rubber 13 (refer FIG. 2) which thickness increases as it goes to a large diameter side end, or the truncated cone-shaped cylindrical rubber 13 (refer FIG. 3) with constant thickness can be created freely. Further, if the rotational speed Vr is set so as to gradually increase, remain unchanged, or decrease as the amount of movement of the mandrel 1 in the direction of arrow B increases, a truncated cone-shaped cylindrical rubber whose thickness decreases toward the large diameter end is created. It is possible.

Example 4
In the molding method according to the fourth embodiment, in the molding process, two or more gains among the three gains of the rotation speed Vr of the mandrel 1, the rubber extrusion speed Vg by the extruder 3, and the relative movement speed Vi of the mandrel 1 are obtained. This is a method for variably controlling. That is, in the control apparatus 12 shown in FIG. 1, it manufactures using the composite control means 12D instead of the extrusion speed control means 12A. By using this composite control means 12D, it is possible to form a cylindrical rubber having a complicated shape and to perform finer control with high accuracy.

[Another Example]
A manufacturing apparatus A having no gear pump 4 may be used. The relative movement speed Vi may be configured such that the mandrel 1 (the bed 6) is fixed in position and the extruder 3 side moves. It is also possible to adopt a method in which the rubber band 11 starts to be wound from the large-diameter side end 1b of the mandrel 1.

Principle diagram showing the structure of a frustoconical cylindrical rubber manufacturing device Sectional view of the frustoconical cylindrical rubber of Example 1 The top view which shows the truncated cone-shaped cylindrical rubber of the preparation example 2 before removing from a mandrel The figure which shows the comparison of the characteristic of creation example 1 and the conventional product The figure which shows the comparison of the characteristic of creation example 2 and various conventional products

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Mandrel 1T Tapered part 3 Extruder 4 Gear pump 11 Belt-shaped rubber A Manufacturing apparatus of cylindrical rubber which has a taper part P Shaft center Vg Rubber extrusion speed Vi Relative moving speed of extruder and mandrel Vr Mandrel rotational speed

Claims (7)

  Rotating the mandrel in a forming process in which a belt-like rubber extruded from an extruder with a predetermined cross-sectional shape is spirally wound around a mandrel having a tapered portion whose outer peripheral length changes as it moves in the axial direction. And relatively moving the extruder and the mandrel in the direction of the rotation axis of the mandrel, and any one of the rubber extrusion speed, the mandrel rotation speed, and the relative movement speed of the extruder. A method for producing a cylindrical rubber having a tapered portion that variably controls two or more speeds.   2. The method for producing a cylindrical rubber having a tapered portion according to claim 1, wherein in the molding step, the extrusion speed is variably controlled while the relative movement speed and the rotation speed of the mandrel are maintained constant.   2. The method for producing a cylindrical rubber having a tapered portion according to claim 1, wherein, in the molding step, the relative movement speed is variably controlled while maintaining the rotation speed and the extrusion speed of the mandrel constant.   2. The method for producing a cylindrical rubber having a tapered portion according to claim 1, wherein in the molding step, the rotation speed is variably controlled while the relative movement speed and the extrusion speed are maintained constant.   The rubber extruded from the extruder is wound around the mandrel via a gear pump, and the extrusion speed of the extruder is variably controlled in synchronization with the discharge speed of the gear pump. The manufacturing method of the cylindrical rubber which has a taper part of description.   The manufacturing method of the cylindrical rubber which has a taper part as described in any one of Claims 1-5 which presses the rubber wound around the said mandrel by the said formation process in the internal diameter side direction of the said mandrel. The cylindrical rubber which has a taper part produced by the manufacturing method of the cylindrical rubber which has a taper part as described in any one of Claims 1-6.

Images