Die for CIP (cleaning in place) forming of ceramic tubular product

Abstract

A mold for CIP forming of a ceramic tubular product comprises a base provided with an inserting groove, a mold body and a powder filling fixing piece located on the outer side of the base, and a positioning hole is formed in the bottom face of the inserting groove. The mold main body comprises a fixed pipe, an outer sleeve and a core rod; one end of the outer sleeve is inserted into the inserting groove, the other end of the outer sleeve extends out of the inserting groove, and an annular inserting area is formed between the outer side face of the outer sleeve and the inner side face of the inserting groove; one end of the core rod is inserted into the positioning hole, and the other end of the core rod extends out of the outer sleeve; the fixing pipe is located in the annular inserting area and abuts against the outer side face of the outer sleeve and the inner side face of the inserting groove. A powder filling space is formed between the outer sleeve and the core rod; the powder filling fixing part comprises a limiting pipe connected to the fixing pipe in a sleeving mode and an end cover fixed to the side, opposite to the base, of the limiting pipe, the inner side face of the limiting pipe abuts against the outer side face of the fixing pipe, the end face of the outer sleeve abuts against the inner side face of the end cover, and the end cover is provided with a penetrating hole connected with the core rod in a penetrating mode and a feeding hole located beside the penetrating hole and communicated with the powder filling space.

Description

Technical Field

[0001] The utility model relates to the technical field of CIP molding of ceramic tubes, in particular to a mold for CIP molding of ceramic tube-shaped products. Background Art

[0002] CIP (Cold Isostatic Pressing) molding is a powder material molding process at room temperature that uses rubber or plastic as the sheathing mold material and liquid as the pressure medium. It is used to provide a green body for further sintering, forging, or hot isostatic pressing processes. Currently, in the CIP molding process of ceramic tubular products, CIP molding molds are mainly used to produce green bodies. Specifically, a rubber mold is used as the outer sleeve, a metal rod is used as the middle core rod, and the outer core rod and the plugs at both ends are made of rubber material. During production, the outer sleeve, the plug at the large end of the core rod, and the core rod are assembled in sequence. Then, powder is filled into the outer sleeve. After the powder is filled, the plug is inserted and the two ends of the core rod are locked with hose clamps. The mold is then sent to the CIP equipment. When using the aforementioned CIP mold, the mold's long center core rod makes it difficult for the bottom plug to support the rod during CIP molding. This can cause the core rod to deviate from the center during powder filling, resulting in uneven green body density and insufficient product concentricity. This can also lead to uneven edges (the thickness difference between the large and small edges is 0.8mm), making the green body prone to cracking during subsequent processing and increasing the product defect rate. The industry's main approach is to increase the margin of difference (by 0.8mm) to make the original large and small edges have the same thickness. However, this solution increases the amount of post-processing processing, thereby increasing the processing cost of the post-process. Utility Model Content

[0003] Based on this, it is necessary to address the above-mentioned shortcomings and provide a mold for CIP molding of ceramic tubular products with high product concentricity and no need to increase the difference margin at the edge to reduce the post-process processing volume and processing cost. The mold can adapt to the CIP processing requirements of ceramic tubular products with concentricity and roundness greater than 0.25mm.

[0004] A mold for CIP molding of ceramic tubular products, comprising:

[0005] A base, wherein the upper surface of the base is provided with a plug-in slot, and the bottom surface of the plug-in slot is provided with a positioning hole;

[0006] The mold body includes a fixed tube, an outer tube, and a core rod. One end of the outer tube is inserted into the plug-in slot, and the other end of the outer tube extends out of the plug-in slot, and an annular plug-in area is formed between the outer side surface of the outer tube and the inner side surface of the plug-in slot; the core rod passes through the inner cavity of the outer tube, one end of the core rod is inserted into the positioning hole, and the other end of the core rod extends out of the inner cavity of the outer tube; the fixed tube is located in the annular plug-in area, the inner side surface of the fixed tube abuts the outer side surface of the outer tube, and the outer side surface of the fixed tube abuts the inner side surface of the plug-in slot; a powder filling space is formed between the outer tube and the core rod;

[0007] A powder filling fixing part, which is located on the outside of the base, includes a limiting tube sleeved on the fixed tube and an end cover located on the side of the limiting tube facing away from the base and fixedly connected to the limiting tube. The inner side surface of the limiting tube abuts the outer side surface of the fixed tube, and the side of the end cover adjacent to the base abuts the end surface of the outer sleeve facing away from the base. The end cover is provided with a through hole located in the middle of the end cover for passing the core rod, and a feed hole located beside the through hole and connected to the powder filling space, and the outer annular surface of the core rod abuts the inner side surface of the through hole.

[0008] In one embodiment, an inclined material guiding surface is formed on the edge of the feed hole on the end cover.

[0009] In one embodiment, the feed hole is a fan-shaped hole that half surrounds the penetration hole, and the inclined material guiding surface is a fan-shaped inclined surface.

[0010] In one embodiment, the projection of the fan-shaped inclined surface on the side of the end cover facing away from the base forms a fan ring, and the central angle of the fan ring is less than or equal to 270°.

[0011] In one embodiment, a plurality of through holes are evenly formed on the outer side surface of the fixing tube, and the through holes are communicated with the inner cavity of the fixing tube.

[0012] In one embodiment, the outer side surface of the fixing tube is provided with M rows of through holes along the circumferential direction of the fixing tube, each row of through holes includes N through holes extending along the axial direction of the fixing tube, and M and N are both integers greater than or equal to 2.

[0013] In one embodiment, the base includes a first base and a second base located above the first base and detachably connected to the first base, the first base is provided with a first hole that at least passes through the upper surface of the first base, the second base is provided with a second hole that passes through the upper surface of the second base and the lower surface of the second base, the first hole forms the positioning hole, the second hole is concentrically arranged and connected to the first hole, the inner diameter of the second hole is larger than the inner diameter of the first hole, and the inner side surface of the second hole and the upper surface of the first base are enclosed to form the plug-in slot.

[0014] In one embodiment, the first base and the second base are connected by a fixing pin.

[0015] In one embodiment, the mold for CIP molding of ceramic tubular products further includes a throat clamp located at the end of the fixed tube and detachably clamped to the outer surface of the outer sleeve, and a tubular plug located in the plug groove and used to seal the powder filling space.

[0016] In one embodiment, a avoidance groove connected to the plug-in groove is opened on the upper surface of the base beside the plug-in groove, the depth of the avoidance groove is the same as the depth of the plug-in groove, and the inner contour shape of the avoidance groove is adapted to the outer contour shape of the throat clamp.

[0017] The mold for CIP molding of ceramic tubular products of the present invention adopts a base and a fixed tube to jointly define the position of the outer sleeve, and uses the positioning hole on the base to define the position of the core rod, so as to limit the outer sleeve and one end of the core rod. By sleeve-fitting the powder filling fixing piece on the other end of the mold body, the sleeve and the other end of the core rod are limited, so that the width at different height positions in the powder filling space is the same, thereby ensuring the concentricity of the green body formed after the powder filling, so as to improve the large and small edge problems of the green body caused by uneven filling in subsequent processing, and no additional green body edge difference margin is required, thereby reducing the post-process processing amount and reducing the post-process processing cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic structural diagram of a mold in one embodiment of the present invention;

[0019] Figure 2 This is a schematic cross-sectional view of a mold in one embodiment of the present invention;

[0020] Figure 3 This is a diagram of the clamping structure when the green body is sent to the CIP process in one embodiment of the present invention;

[0021] Figure 4 This is a cross-sectional structural diagram of the clamping when the blank is sent to the CIP process in one embodiment of the present invention. DETAILED DESCRIPTION

[0022] To make the above-mentioned objects, features, and advantages of the present invention more clearly understood, the following detailed description of specific embodiments of the present invention is provided in conjunction with the accompanying drawings. The following description sets forth many specific details to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways than those described herein, and those skilled in the art may make similar modifications without departing from the scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0023] Please combine Figure 1 and Figure 2The utility model discloses a mold for CIP molding of ceramic tubular products, which has high product concentricity and does not require an increase in edge difference margin to reduce post-process processing volume and processing costs. The mold includes a base 100, a mold body 200 and a powder filling fixing part 300. The upper surface of the base 100 is provided with a plug-in groove 110, and the bottom surface of the plug-in groove 110 is provided with a positioning hole 120. The mold body 200 includes a fixed tube 210, an outer tube 220 and a core rod 230. One end of the outer tube 220 is inserted into the plug-in groove 110, and the other end of the outer tube 220 extends out of the plug-in groove 110, and an annular plug-in area is formed between the outer side surface of the outer tube 220 and the inner side surface of the plug-in groove 110; the core rod 230 passes through the inner cavity of the outer tube 220, one end of the core rod 230 is inserted into the positioning hole 120, and the other end of the core rod 230 extends out of the inner cavity of the outer tube 220; the fixed tube 210 is located in the annular plug-in area, the inner side surface of the fixed tube 210 abuts against the outer side surface of the outer tube 220, and the outer side surface of the fixed tube 210 abuts against the inner side surface of the plug-in groove 110; a powder filling space 240 is formed between the outer tube 220 and the core rod 230. The powder filling fixing part 300 is located on the outside of the base 100, and includes a limiting tube 310 that is sleeved on the fixing tube 210 and an end cover 320 that is located on the side of the limiting tube 310 facing away from the base 100 and fixedly connected to the limiting tube 310. The inner side surface of the limiting tube 310 abuts against the outer side surface of the fixing tube 210, and the side of the end cover 320 adjacent to the base 100 abuts against an end surface of the outer sleeve 220 facing away from the base 100. The end cover 320 is provided with a through hole 321 located in the middle of the end cover 320 and used to pass through the core rod 230, and a feed hole 322 located next to the through hole 321 and connected to the powder filling space 240, and the outer annular surface of the core rod 230 abuts against the inner side surface of the through hole 321. In this embodiment, the outer sleeve 220 is made of rubber, the core rod 230 is made of tungsten steel, and the fixed tube 210, base 100, and powder filling fixture 300 are all made of steel to ensure the mechanical strength of the mold. Of course, other metal materials, such as aluminum alloy or copper, can also be used to make the fixed tube 210, base 100, and powder filling fixture 300 while ensuring the mechanical strength of the mold. These materials will not be described in detail here.

[0024] It can also be understood that in the above structure, one end of the mold body 200 is inserted into the base 100, and the base 100 positions the one end of the mold body 200, while the other end of the mold body 200 is located outside the base 100 and is positioned by the powder filling fixture 300. Specifically, the positioning hole 120 is used to define the position of one end of the core rod 230, and the through-hole 321 is used to define the position of the other end of the core rod 230. The inner wall of the insertion groove 110 of the base 100 is used to press one end of the fixing tube 210 to constrain one end of the outer sleeve 220, and the inner wall of the limiting tube 310 is used to press the other end of the fixing tube 210 to constrain the other end of the outer sleeve 220. In this way, the concentricity of the outer sleeve 220 and the core rod 230 is ensured, so that the width of the powder filling space 240 at different height positions in the annular structure is the same, thereby avoiding the occurrence of uneven powder filling in the blank.

[0025] In one embodiment, an inclined guide surface 323 is formed on the edge of the feed hole 322 on the end cap 320 to increase the powder feeding area on the end cap 320. At the same time, when the powder is discharged onto the inclined guide surface 323, the powder will slide along the inclined guide surface 323 under the action of gravity. In this way, the powder can be quickly filled without the need for an external funnel to fill the powder, reducing the difficulty of powder filling and improving the efficiency of powder filling. Furthermore, the feed hole 322 is a fan-shaped hole that semi-encloses the through-hole 321, and the inclined guide surface 323 is a fan-shaped inclined surface. Preferably, the projection of the fan-shaped inclined surface on the side of the end cap 320 facing away from the base 100 forms a fan ring, and the central angle of the fan ring is less than or equal to 270°. In this way, while ensuring the structural stability of the mating portion between the end cover 320 and the core rod 230 and preventing the core rod 230 positioning failure caused by the breakage of the mating portion between the end cover 320 and the core rod 230, the feeding area on the end cover 320 is increased, further improving the powder filling efficiency.

[0026] In this embodiment, the fixed tube 210 is nested outside the outer sleeve 220 and serves as a reference for defining the concentricity of the product. Since the mold of this solution is mainly used for ceramic tubular products in smart terminal electronic products such as tablet computers, the target product size is relatively small. In this embodiment, the outer diameter of the fixed tube 210 is 36.28mm, the inner diameter of the fixed tube 210 is 24.27mm, and the length of the fixed tube 210 is 174mm. The outer diameter of the outer sleeve 220 is 24.27mm and the length of the outer sleeve 220 is 208mm. When the fixed tube 210 is sleeved on the outer sleeve 220, the two ends of the fixed end are each 16mm shorter than the ends of the outer sleeve 220. The outer diameter of the core rod 230 is 9.2mm, the inner diameter of the insertion groove 110 is 36.28mm, the depth of the insertion groove 110 is 80mm, and the inner diameter of the positioning hole 120 is 9.2mm and the depth of the positioning hole 120 is 20mm.

[0027] In one embodiment, a plurality of through holes 211 are uniformly provided on the outer side of the fixed tube 210, and the through holes 211 are connected to the inner cavity of the fixed tube 210. Furthermore, the outer side of the fixed tube 210 is provided with M rows of through holes 211 along the circumference of the fixed tube 210, and each row of through holes 211 includes N through holes 211 extending axially along the fixed tube 210, where M and N are both integers greater than or equal to 2. Preferably, in this embodiment, the outer side of the fixed tube 210 is provided with four rows of through holes 211 along the circumference of the fixed tube 210, and each row of through holes 211 includes six through holes 211 extending axially along the fixed tube 210. By uniformly providing a plurality of through holes 211 on the fixed tube 210, the pressure transmitted to the outer sleeve 220 through each through hole 211 during CIP manufacturing can be uniform, thereby ensuring the processing quality of the product.

[0028] In this embodiment, the base 100 includes a first base 130 and a second base 140 located above the first base 130 and detachably connected to the first base 130. The first base 130 is provided with a first hole that at least penetrates the upper surface of the first base 130, and the second base 140 is provided with a second hole that penetrates the upper surface of the second base 140 and the lower surface of the second base 140. The first hole forms a positioning hole 120, and the second hole is concentrically arranged and connected to the first hole. The inner diameter of the second hole is larger than the inner diameter of the first hole, and the inner side surface of the second hole and the upper surface of the first base 130 enclose a plug-in slot 110. Preferably, the first hole penetrates the upper surface of the first base 130 and the lower surface of the first base 130. In this embodiment, the base 100 is split into the first base 130 and the second base 140, which reduces the difficulty of processing the base 100. In addition, in this embodiment, the first base 130 and the second base 140 are connected by a fixing pin 150. Specifically, a first slot is provided on the upper surface of the first base 130, and a second slot is provided on the lower surface of the second base 140. The two ends of the fixing pin 150 are respectively inserted into the first slot and the second slot, and the fixing pin 150 is respectively tightened with the inner surface of the first slot and the inner surface of the second slot to achieve a fixed connection between the first base 130 and the second base 140.

[0029] Please further combine Figure 1-4The mold for forming ceramic tubular products also includes a throat clamp 400 located at the end of the fixed tube 210 and removably clamped to the outer surface of the outer sleeve 220, and a tubular plug 500 located in the insertion groove 110 and used to seal the powder filling space 240. The tubular plug 500 is used to seal the bottom end of the powder filling space 240 to achieve the shaping of the bottom of the blank. The throat clamp 400 is used to clamp the outer sleeve 220 so that after the powder filling space 240 is filled with powder and the blank is formed, the blank is shaped. The throat clamp 400 has an arc-shaped clamping surface that adapts to the shape of the outer surface of the outer sleeve 220. The arc-shaped clamping surface is a superior arc structure, that is, the central angle corresponding to the arc-shaped clamping surface is greater than 180 degrees, so as to ensure the stability of the throat clamp 400 clamped on the outer sleeve 220. In addition, in this embodiment, a relief groove 160 is formed on the upper surface of the base 100, adjacent to the insertion groove 110, and communicates with the insertion groove 110. The depth of the relief groove 160 is the same as that of the insertion groove 110, and the inner contour of the relief groove 160 is adapted to the outer contour of the throat clamp 400. Thus, before the powder filling operation, the throat clamp 400 is clamped to the lower portion of the outer sleeve 220, and the throat clamp 400 is placed into the insertion groove 110 of the base 100 along with the tubular plug 500, outer sleeve 220, core rod 230, and fixed tube 210, thereby saving mold loading time.

[0030] Furthermore, during the CIP process for ceramic tubular products, a CIP fixture 600 is used to position the top and bottom of the mold, assisting in shaping the blank. Specifically, the CIP fixture 600 is a hollow cylindrical structure with an opening at one end. A notch 610 is defined on the side surface of the CIP fixture 600, communicating with the inner cavity of the CIP fixture 600. This notch 610 is also connected to the opening of the CIP fixture 600, and the width of the notch 610 is the same as that of the throat clamp 400. When the CIP fixture 600 is sleeved onto the end of the fixed tube 210, the throat clamp 400 is positioned within the notch 610, thereby limiting the position of the throat clamp 400 and preventing it from rotating.

[0031] During the CIP molding process for ceramic tubular products, the core rod 230 is first inserted into the inner cavity of the outer sleeve 220, and the fixed tube 210 is nested within the outer wall of the outer sleeve 220. The powder filling fixture 300 is sleeved onto the top of the fixed tube 210, and the core rod 230 is passed through the through-hole 321 in the end cap 320. Subsequently, the tubular plug 500 is sealed at the bottom of the powder filling space 240, with the outer surface of the tubular plug 500 abutting against the inner surface of the outer sleeve 220, and the inner surface of the tubular plug 500 abutting against the annular surface of the core rod 230. Simultaneously, the throat clamp 400 is clamped to the lower portion of the outer sleeve 220 and placed into the insertion slot 110 of the base 100 along with the tubular plug 500, outer sleeve 220, core rod 230, and fixed tube 210, so that the core rod 230 is inserted into the positioning hole 120 of the base 100. During the powder filling process, the powder filling fixture 300 can be rotated to change the position of the feed hole 322 on the powder filling fixture 300 relative to the powder filling space 240, thereby ensuring uniform filling of the powder in the powder filling space 240. After the powder filling is completed, the powder filling fixture 300 on the upper portion of the mold body 200 can be removed, and another tubular plug 500 can be inserted into the upper portion of the mold body 200. At the same time, another hose clamp 400 is used to clamp the upper portion of the outer sleeve 220, thereby achieving a fixed shape and sealing of the powder in the powder filling space 240, thereby obtaining a green body.

[0032] Before entering the CIP process, a CIP fixture 600 is placed on each end of the mold. The throat clamps 400 at both ends of the mold are positioned using the notches 610 on the CIP fixture 600. The end of the tubular plug 500 is then abutted against the inner bottom surface of the CIP fixture 600, while the inner side of the CIP fixture 600 is abutted against the outer side of the fixing ring to secure the two ends of the mold. The mold, secured with the CIP fixture 600, is then placed into the CIP equipment and pressed at a pressure of 180 MPa for 10 minutes to obtain a CIP-treated green body. The green body is then removed and sent to the sintering equipment. After using the above mold to produce a green body and performing CIP pressing and sintering on the green body, the product's eccentricity problem is reduced from the original 0.80 mm difference between the large and small sides to 0.20 mm, improving the defect of eccentricity between the large and small sides of the product. Of course, in actual operation, when the powder is loaded into the mold, the tubular plug 500 and the throat clamp 400 at the lower portion of the outer sleeve 220 can also be removed. In this way, after the powder is filled, the powder filling fixture 300 can be removed first, and the tubular plug 500 and the throat clamp 400 can be clamped on the top of the outer sleeve 220. Then, the entire mold is inverted, the base 100 is removed, and the tubular plug 500 and the throat clamp 400 are clamped on the outer sleeve 220 at the position originally matched with the base 100 to achieve the encapsulation of the powder.

[0033] The mold for CIP molding of ceramic tubular products of the present invention adopts a base 100 and a fixed tube 210 to jointly define the position of the outer sleeve 220, and uses the positioning hole 120 on the base 100 to define the position of the core rod 230, thereby limiting the outer sleeve 220 and one end of the core rod 230. By sleeve-fitting the powder filling fixing part 300 on the other end of the mold body 200, the other end of the sleeve and the core rod 230 is limited, so that the width of different height positions in the powder filling space 240 is the same, thereby ensuring the concentricity of the green body formed after the powder filling, so as to improve the large and small edge problems of the green body caused by uneven filling in subsequent processing, without the need to increase the green body edge difference margin, reducing the post-process processing amount and reducing the post-process processing cost.

[0034] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0035] The above-described embodiments merely represent several implementations of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the utility model patent. It should be noted that a person skilled in the art would be able to make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements fall within the scope of protection of the present invention. Therefore, the scope of protection of the present utility model patent shall be determined by the appended claims.

Claims

1. A mold for CIP molding of ceramic tubular products, characterized in that: include: A base, wherein the upper surface of the base is provided with a plug-in slot, and the bottom surface of the plug-in slot is provided with a positioning hole; The mold body includes a fixed tube, an outer tube, and a core rod. One end of the outer tube is inserted into the plug-in slot, and the other end of the outer tube extends out of the plug-in slot, and an annular plug-in area is formed between the outer side surface of the outer tube and the inner side surface of the plug-in slot; the core rod passes through the inner cavity of the outer tube, one end of the core rod is inserted into the positioning hole, and the other end of the core rod extends out of the inner cavity of the outer tube; the fixed tube is located in the annular plug-in area, the inner side surface of the fixed tube abuts the outer side surface of the outer tube, and the outer side surface of the fixed tube abuts the inner side surface of the plug-in slot; a powder filling space is formed between the outer tube and the core rod; A powder filling fixing part, which is located on the outside of the base, includes a limiting tube sleeved on the fixed tube and an end cover located on the side of the limiting tube facing away from the base and fixedly connected to the limiting tube. The inner side surface of the limiting tube abuts the outer side surface of the fixed tube, and the side of the end cover adjacent to the base abuts the end surface of the outer sleeve facing away from the base. The end cover is provided with a through hole located in the middle of the end cover for passing the core rod, and a feed hole located beside the through hole and connected to the powder filling space, and the outer annular surface of the core rod abuts the inner side surface of the through hole.

2. The mold according to claim 1, characterized in that An inclined material guiding surface is formed on the end cover at the edge of the material feeding hole.

3. The mold according to claim 2, characterized in that The feed hole is a fan-shaped hole that half surrounds the penetration hole, and the inclined material guiding surface is a fan-shaped inclined surface.

4. The mold according to claim 3, characterized in that The projection of the sector-shaped inclined surface on the side of the end cover facing away from the base forms a sector ring, and the central angle of the sector ring is less than or equal to 270°.

5. The mold according to claim 1, characterized in that A plurality of through holes are evenly formed on the outer side surface of the fixing tube, and the through holes are communicated with the inner cavity of the fixing tube.

6. The mold according to claim 5, characterized in that The outer side surface of the fixed tube is provided with M rows of through holes along the circumferential direction of the fixed tube, each row of through holes includes N through holes extending along the axial direction of the fixed tube, and M and N are both integers greater than or equal to 2.

7. The mold according to claim 1, characterized in that The base includes a first base and a second base located above the first base and detachably connected to the first base. The first base is provided with a first hole that at least passes through the upper surface of the first base, and the second base is provided with a second hole that passes through the upper surface of the second base and the lower surface of the second base. The first hole forms the positioning hole, and the second hole is concentrically arranged and connected to the first hole. The inner diameter of the second hole is larger than the inner diameter of the first hole, and the inner side surface of the second hole and the upper surface of the first base enclose to form the plug-in groove.

8. The mold according to claim 7, characterized in that The first base is connected to the second base via a fixing pin.

9. The mold according to claim 1, characterized in that The utility model also comprises a throat clamp which is located at the end of the fixed pipe and is detachably clamped on the outer surface of the outer sleeve, and a tubular plug which is located in the plug-in groove and is used for sealing the powder filling space.

10. The mold according to claim 9, characterized in that The upper surface of the base is provided with a avoidance groove connected to the plug-in groove beside the plug-in groove. The depth of the avoidance groove is the same as that of the plug-in groove, and the inner contour shape of the avoidance groove is adapted to the outer contour shape of the throat clamp.

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