Cored rivet installation tool

Abstract

The application provides a core-pulling rivet installation tool, which comprises a shell, a driving unit contained in the shell, a pulling unit, a clamping unit and a nose portion. The clamping unit comprises a plurality of clamping blocks arranged in sequence at an angle around the pulling direction. The clamping blocks comprise a plurality of clamping teeth towards the inner side of the core rod of the core-pulling rivet. The clamping teeth located at the front section of the clamping blocks are at least partially removed in advance, so as to reduce or remove the stress concentration or shearing force formed on the front section of the clamping blocks by the clamping sleeve and the core-pulling rivet during the pull riveting process due to the fact that the core rod of the core-pulling rivet is not always parallel to the axis R during the pull riveting, and the uneven force is caused by the actual processing tolerance or design. Thus, the early wear or breakage of the clamping teeth on the inner side of the clamping blocks is avoided, the service life of the clamping blocks is prolonged, and the repair rate of the rivet installation tool is greatly reduced.

Description

TECHNICAL FIELD

[0001] The present invention relates to a fastening device, and more particularly, to a blind rivet installation tool. BACKGROUND

[0002] Blind rivet installation tools are commonly used to install fastening blind rivets, such as blind rivets, blind rivet nuts, and the like. The installation fastening process of blind rivets is known.

[0003] Referring to Figure 1 With Figure 2 , the existing pull rivet gun as disclosed in Chinese patent application document CN110834060A is suitable for installing a blind rivet 9 (as shown in Figure 1 ), and comprises a housing 2, a driving unit 3, a pulling unit 4, a clamping unit 5, a nose part 6, and a sensing unit 7. The pulling unit 4 comprises a screw rod 42 extending along the second axis R2, and a connecting piece 43 connected to the screw rod 42. The clamping unit 5 comprises a clamping sleeve 51 connected to the connecting piece 43, a plurality of clamping blocks 52 arranged in angle around the second axis R2 in sequence, a center rod 53, a clamping spring 54, and a limiting piece 55. The clamping sleeve 51 has a surrounding wall 511, and a clamping opening 512 defined by the surrounding wall 511. The clamping blocks 52 are arranged in the surrounding wall 511 and adjacent to the clamping opening 512. The clamping spring 54 can generate an elastic force to keep the center rod 53 constantly abutting against the clamping blocks 52. The clamping blocks 52 can pass through the clamping opening 512 and move towards the second axis R2 to clamp the pull rivet 9 when they are abutted by the center rod 53. The clamping blocks 52 have a plurality of clamping teeth or ribs inside, which are configured and arranged to improve the engagement with the rivet core rod (not shown).

[0004] When approaching the termination position (as shown in Figure 2 ), the clamping spring 54 pushes against the head 531 of the center rod 53, and then the head 531 pushes against the clamping blocks 52, so that the clamping blocks 52 move towards the direction of the clamping opening 512 and pass through the clamping sleeve 51 from the clamping opening 512. When the clamping blocks 52 are pushed by the head 531 to move towards the direction of the clamping opening 512, the clamping blocks 52 also gradually approach the second axis R2, and then can clamp the blind rivet 9.

[0005] However, when approaching the end position, the back of the clamping block 52 is supported on the clamping sleeve 51 in a face contact manner. When installing the hollow rivet fastener, part of the pulling force is used to form the closed head of the hollow rivet fastener, and the other part of the pulling force is used to generate a clamping force by which the clamping block 52 is clamped against the rivet core rod. Thus, the clamping teeth inside the clamping block 52 for engaging the rivet core rod will be subjected to a greater pressure, especially the clamping teeth corresponding to the front end position of the clamping sleeve 51, which are subjected to the greatest load, and therefore, the clamping teeth inside the clamping block 52 are often rapidly worn or broken, resulting in the installation tool being unable to be used normally. SUMMARY

[0006] The present application aims to provide a hollow rivet installation tool, which can effectively solve the problem that the installation tool cannot be used normally due to the damage or wear of the clamping teeth inside the clamping block of the clamping unit of the installation tool, and reduce the repair rate of the installation tool.

[0007] According to one embodiment of the present application, a hollow rivet installation tool comprises a housing, a driving unit accommodated in the housing, a pulling unit, a clamping unit, and a nose portion, the clamping unit comprising a clamping sleeve connected to the pulling unit, a plurality of clamping blocks arranged in sequence at an angle around the pulling direction, and a clamping spring, the clamping sleeve having a surrounding wall and a clamping opening defined by the surrounding wall, the back of the clamping block abutting against the inner wall of the surrounding wall, the inside of the clamping block towards the inner side of the rivet core rod comprising a plurality of clamping teeth for improving the clamping of the clamping block on the rivet core rod, the clamping spring being configured to enable the clamping block to move in the clamping sleeve between an initial position and an end position, when the clamping block is in the end position, the front section of the clamping block protruding out of the clamping opening, the rear section of the clamping block remaining in the clamping sleeve, and the clamping teeth of the front section of the clamping block being at least partially removed.

[0008] According to one preferred embodiment of the present application, the clamping teeth of the front section of the clamping block are all removed.

[0009] According to another preferred embodiment of the present application, the clamping teeth of the front section of the clamping block are partially removed, and the height of the clamping teeth of the front section of the clamping block is smaller than the height of the clamping teeth of the rear section of the clamping block.

[0010] According to yet another preferred embodiment of the present application, when the clamping block is in the end position, the clamping teeth of the front section of the clamping block closest to the clamping opening are at least partially or completely removed.

[0011] Preferably, the clamping teeth are ribs arranged on the clamping block substantially along the pulling direction, the ribs comprising a top edge substantially perpendicular to the center line of the core rod, and a first side surface extending from the top edge to the clamping tooth root portion at a first angle with respect to the pulling direction toward the driving unit, and a second side surface extending from the top edge to the clamping tooth root portion at a second angle with respect to the pulling direction toward the nose portion.

[0012] More preferably, the first side surface and the second side surface form a smooth transition fillet at the tooth root portion of the clamping teeth.

[0013] More preferably, the first angle is greater than the second angle.

[0014] The top edge of the clamping teeth of the rear section of the clamping block is at least partially in surface contact with the outer circumferential surface of the core rod.

[0015] According to an embodiment of the present application, the clamping block is made of medium-carbon nickel-chromium-molybdenum alloy steel with a nickel content of about 1.6-2.0%.

[0016] According to an embodiment of the present application, the clamping block is heat treated to have a hardening layer depth of 0.5-0.8 mm and a surface hardness of not less than HV680.

[0017] The core-pulling rivet installation tool of the present application, when performing rivet installation, clamps the core rod of the core-pulling rivet with the clamping block, and when in the termination position, the front section of the clamping block protrudes from the clamping opening. By previously removing at least part of the clamping teeth of the front section of the clamping block, the front section of the clamping block can function as a clearance, reducing or removing the stress concentration or shear force formed on the front section of the clamping block due to the uneven force caused by actual processing tolerance or design during the riveting process of the clamping sleeve and the core-pulling rivet, thereby avoiding early wear or breakage of the clamping teeth on the inner side of the clamping block, improving the service life of the clamping block, and greatly reducing the repair rate of the rivet installation tool. BRIEF DESCRIPTION OF DRAWINGS

[0018] The embodiments can be better understood with reference to the following detailed description when considered in connection with the accompanying drawings, in which like reference numerals designate identical elements. It is to be expressly understood, however, that the drawings are included merely for purposes of illustration and description and are not intended as part of the specification. In the figures, like numbers indicate like parts throughout the several views.

[0019] Figure 1 is a sectional view of an existing rivet installation tool in an initial position;

[0020] Figure 2 is a sectional view of the existing rivet installation tool as shown in Figure 1 is a sectional view of the existing rivet installation tool in a termination position;

[0021] Figure 3 is a partial perspective exploded view of an embodiment of the rivet setting tool of the present invention;

[0022] Figure 4 is a partial perspective view of an embodiment of the rivet setting tool of the present invention; Figure 3 is a partial cross-sectional view of an embodiment of the rivet setting tool of the present invention in its initial position;

[0023] Figure 5 is a partial cross-sectional view of an embodiment of the rivet setting tool of the present invention in its final position; Figure 3

[0024] Figure 6 is a schematic view of the clamping block of the rivet setting tool of the present invention;

[0025] Figure 7 is a schematic projection of the clamping block of the rivet setting tool of the embodiment shown; Figure 6

[0026] Figure 8 is a partial enlarged schematic view of the clamping block of the rivet setting tool of the embodiment shown; Figure 7

[0027] Figure 9 is a schematic projection of the clamping block of the rivet setting tool of another embodiment of the present invention;

[0028] Figure 10 is a schematic projection of the clamping block of the rivet setting tool of yet another embodiment of the present invention. DETAILED DESCRIPTION

[0029] In the following, a rivet setting tool according to the present invention will be described with reference to the drawings. Figures 3 to 10

[0030] With reference to the drawings, an embodiment of the core-pulling rivet setting tool of the present invention, which is suitable for setting a core-pulling rivet 7, will be described. The core-pulling rivet setting tool 1 comprises a housing 2, a drive unit 3 accommodated in the housing, a pulling unit 4, a clamping unit 5, and a nose 6. The pulling unit 4, the clamping unit 4 and the nose 6 define an axis R extending in the pulling direction. Figures 3 to 5

[0031] ​​​​​The clamping unit 5 comprises a clamping sleeve 50 connected to the pulling unit 4, a plurality of clamping blocks 51 arranged in sequence at an angle to the pulling direction, and a clamping spring 54. The clamping sleeve 50 has a surrounding wall 52 and a clamping opening 53 defined by the surrounding wall 52. The back of the clamping block 51 abuts against the inner wall of the surrounding wall 52. The clamping block 51 comprises a plurality of clamping teeth 55 on the inner side thereof towards the inside of the rivet core rod 8 for improving the clamping of the clamping block 51 to the rivet core rod. Preferably, the clamping teeth 55 are protruding ribs arranged uniformly along the pulling direction on the clamping block. The clamping spring 54 is configured to move the clamping block 51 in the clamping sleeve 50 between an initial position and a final position. As shown in Figure 4 the clamping block 51 is in its final position, the front section 511 of the clamping block protrudes out of the clamping opening 53, and the rear section 512 of the clamping block remains in the clamping sleeve 50.

[0032] Referring to Figure 3 When the clamping unit of the rivet installation tool of the present application is in its initial position, the clamping sleeve 50 is adjacent to the nose 6. The clamping block 51 abuts against one end of the nose 6 and does not protrude out of the clamping sleeve 51 through the clamping opening 32. The clamping block 51 is located in the clamping space surrounded by the surrounding wall 52 and is radially spaced from the axis R, so that the core rod 8 of the hollow rivet 7 can be put between the clamping blocks 51 through the axial hole of the nose 6. The rear side of the clamping block 52 abuts against a center rod 56 and compresses the clamping spring 54. In the initial position, the clamping teeth 55 on the inner side of the clamping block 51 do not exert a clamping force on the core rod 8 in the radial direction.

[0033] The clamping sleeve 50 can be moved along the axis R by the screw rod of the pulling unit and reaches the final position. As shown in Figure 5 the clamping spring 54 pushes against the head of the center rod 56, which in turn pushes against the clamping block 51, so that the clamping block 51 moves towards the clamping opening 53 and protrudes out of the clamping sleeve 50 through the clamping opening 53. When the clamping block 51 is pushed by the center rod 56 to move towards the clamping opening 53, the clamping block 51 gradually approaches the axis R as the hole diameter of the surrounding wall 52 gradually decreases to the clamping opening 53, and the clamping teeth 55 at least partially contact and clamp the core rod of the hollow rivet. In the approach to the final position, the back of the clamping block 51 is supported on the inner wall of the surrounding wall 52 of the clamping sleeve 50 in a surface contact manner. When installing the hollow rivet fastener, the pulling direction is as shown in Figure 5As shown in the figure, part of the pulling force is used to form the closed head of the blind rivet 7, and the other part of the pulling force is used to generate the clamping force by which the clamping block 51 is clamped against the core rod 8 of the blind rivet 7. The core rod 8 of the blind rivet 7 is clamped and pulled back, and finally is pulled off and riveted to the plate.

[0034] With reference to Figure 5 , the clamping unit 5 of the rivet installation tool is in its final position, the front section 511 of the clamping block 51 protrudes out of the clamping opening 53, and the rear section 512 of the clamping block remains in the clamping sleeve 50. Ideally, the inner side of the front section 511 and the inner side of the rear section 512 of the clamping block 51 should be completely parallel to the axis R, that is, the front section 511 and the rear section 512 should exert uniform clamping force to the peripheral surface of the core rod 8 in the final position. However, due to the fact that the core rod 8 of the blind rivet 7 is not always completely parallel to the axis R during the pull riveting, and the possible errors in the machining or assembly process, and the wear of the material, the front section 511 of the clamping block protruding out of the clamping opening 53 has a higher clamping force in the radial direction, especially the critical clamping teeth 551 closest to the clamping opening 53, which are subjected to both the radial clamping force and the pulling force in the pulling direction. Therefore, the clamping teeth of the front section 511 of the clamping block, especially the critical clamping teeth 551 closest to the clamping opening 53, are the most prone to wear or breakage. In order to avoid the wear or breakage of the clamping teeth, the clamping teeth of the front section of the clamping block of the rivet installation tool of the present application are at least partially removed in advance to serve as a relief for reducing or eliminating the stress concentration or shear force caused by the fact that the core rod of the blind rivet is not always completely parallel to the axis R during the pull riveting, and the uneven forces caused by the actual machining tolerance or design during the pull riveting process.

[0035] According to a preferred embodiment of the present application, with reference to Figure 6 and Figure 7 , the clamping teeth of the front section 511 of the clamping block 51 are all removed, for example, the clamping teeth of the front section are ground off, so that the inner side of the front section 511 of the clamping block 51 is basically a flat surface or an arc surface substantially parallel to part of the peripheral surface of the core rod 8. Since the rear section 512 of the clamping block 51 remains in the clamping sleeve 50, and the thickness of the rear section 512 in the radial direction is higher than that of the front section 511, the rear section 512 has higher tensile strength, and the clamping teeth on the inner side of the rear section 512 are sufficient to ensure the clamping of the core rod of the rivet during the pull riveting process. The advantage of grinding off all the clamping teeth of the front section is that the machining process is simple, and it does not affect the pulling force required for the installation of the blind rivet in the installation process.

[0036] Reference Figures 4 to 7 The clamping teeth 55 are preferably ribs arranged on the clamping block 51 substantially along the pulling direction. Preferably, as shown in Figure 7 and Figure 8 , the ribs comprise a top edge 550 substantially perpendicular to the center line of the core rod, and a first side surface 551 extending from the top edge 550 to the clamping tooth root at a first angle a with respect to the pulling direction, and a second side surface 552 extending from the top edge 550 to the clamping tooth root at a second angle b with respect to the pulling direction. More preferably, the first angle a is greater than the second angle b, so that the clamping teeth 55 are easy to insert into the core rod, thereby enhancing the holding force and reducing the wear. More preferably, the first side surface 551 and the second side surface 552 form a smooth transition fillet at the tooth root of the clamping teeth, to reduce the risk of breakage. More preferably, the top edge 550 of the clamping teeth of the rear section of the clamping block is at least partially in surface contact with the outer peripheral surface of the core rod 8. Thus, the top edge 550 is not a ridge line, but a slightly flat curved surface, which is at least partially in surface contact with the core rod surface when the top edge 550 is clamped to the outer peripheral surface of the core rod, thereby making the clamping teeth less likely to be pulled off, while facilitating reducing the degree of wear of the top edge 550.

[0037] Reference Figure 9 According to another embodiment of the present application, unlike the previous embodiment, the clamping teeth of the front section 511 of the clamping block 51 are not completely removed, but are partially removed. As shown in Figure 9 , the tooth height of the clamping teeth of the front section 511 of the clamping block 51 is less than the tooth height of the clamping teeth of the rear section 512 of the clamping block 51. In this way, stress concentration or shear force due to uneven force caused by the core rod 8 of the core-pulling rivet not always being completely parallel to the axis R and actual machining tolerance or design is avoided, while the number of clamping teeth is maintained, and the force on each clamping tooth during the riveting process is more evenly distributed.

[0038] According to still another preferred embodiment of the present application, as shown in Figure 10 , unlike the previous embodiment, only the clamping teeth closest to the clamping opening 513 on the front section of the clamping block are removed or partially removed. Again, the solution of this embodiment also avoids stress concentration or shear force due to uneven force caused by the core rod not always being completely parallel to the axis R and actual machining tolerance or design, while the number of clamping teeth is maintained, and the force on the clamping teeth during the riveting process is more evenly distributed. Moreover, since only one tooth closest to the clamping opening is removed, the wear resistance of the entire clamping block is higher, and the service life is longer.

[0039] In addition, in order to further improve the wear resistance of the clamping block and reduce the possibility of fracture of the clamping teeth, according to the embodiment of the present application, the clamping block is made of medium-carbon nickel-chromium-molybdenum alloy steel with a nickel content of about 1.6-2.0%, such as SNCM439 / SNCM447 / SNCM431 steel. This steel is an alloy steel containing a high proportion of nickel, which can improve the strength and toughness of the alloy steel and has good wear resistance. At the same time, proper heat treatment of the clamping block can also greatly improve the wear resistance of the clamping block. For example, the clamping block is heat treated, the hardening layer depth is 0.5-0.8mm, and the surface hardness is not less than HV680.

[0040] In summary, the coreless rivet installation tool of the present application can install 70,000 coreless rivets without breaking the clamping teeth by improving the structure of the clamping block and / or selecting more suitable materials and processing technology, greatly reducing the repair rate of the installation tool.

[0041] As described above, although the exemplary embodiments of the present application have been described with reference to the accompanying drawings in the specification, the present application is not limited to the above-described specific embodiments, and many other embodiments can be possible, and the scope of the present application should be defined by the claims and their equivalent meanings.

Claims

1. A blind rivet installation tool, comprising a housing, a drive unit housed within the housing, a pulling unit, a clamping unit, and a nose, the clamping unit comprising a clamping sleeve connected to the pull unit, a plurality of clamping blocks arranged at an angle about a pulling direction, and a clamping spring, the clamping sleeve having a surrounding wall and a clamping opening defined by the surrounding wall, the back of each clamping block abutting against the inner wall of the surrounding wall, each clamping block having a plurality of clamping teeth on its inner side facing the rivet shank for improving the clamping of the rivet shank by the clamping block, the clamping spring being configured to allow the clamping block to move within the clamping sleeve between an initial position and a final position, wherein when the clamping block is in its final position, the front portion of the clamping block protrudes from the clamping opening, and the rear portion of the clamping block is retained in the clamping sleeve, characterized in that... The clamping teeth located at the front section of the clamping block are at least partially removed beforehand. The clamping teeth are ribs that are evenly distributed on the clamping block in a substantially pulling direction. The ribs include a top edge that is substantially perpendicular to the center line of the rivet core rod, and a first side surface that extends from the top edge toward the root of the clamping teeth at a first angle with respect to the pulling direction toward the drive unit, and a second side surface that extends from the top edge toward the root of the clamping teeth at a second angle with respect to the pulling direction toward the nose, wherein the first angle is greater than the second angle.

2. The rivet installation tool according to claim 1, characterized in that, All the clamping teeth at the front of the clamping block were removed.

3. The rivet installation tool according to claim 1, characterized in that, The clamping teeth at the front of the clamping block are partially removed, and the tooth height of the clamping teeth at the front of the clamping block is less than the tooth height of the clamping teeth at the rear of the clamping block.

4. The rivet installation tool according to claim 1, characterized in that, When the clamping block is in the terminated position, the clamping teeth on the front section of the clamping block closest to the clamping opening are at least partially or completely removed.

5. The rivet installation tool according to claim 1, characterized in that, The first side and the second side form a rounded corner with a smooth transition at the root of the clamping tooth.

6. The rivet installation tool according to claim 1, characterized in that, The top edge of the clamping teeth at the rear section of the clamping block is in contact with at least a portion of the outer peripheral surface of the rivet core.

7. The rivet installation tool according to any one of claims 1-6, characterized in that, The clamping block is made of medium-carbon nickel-chromium-molybdenum alloy steel with a nickel content of 1.6-2.0%.

8. The rivet installation tool according to claim 7, characterized in that, The clamping block is heat-treated, with a hardened layer depth of 0.5-0.8 mm and a surface hardness of not less than HV680.

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