A plug screw sleeve

Abstract

The invention discloses a latch screw sleeve. It comprises a screw sleeve body and a keyway of the body, wherein a latch is arranged in the keyway, and the latch is composed of an action part, a transition part and a guide part; the keyway is composed of a keyway dovetail part and a keyway rectangular part; the two sides from the guide part to the transition part are continuous arc transitions, and the arc vertex is located at the guide part. The arc transition of the guide part and the transition part of the invention can reduce the wear of the mold and increase the service life; the latch and the keyway have an interference fit to ensure that the latch and the screw sleeve do not fall off; the height of the guide part does not exceed the difference between the minor diameter of the outer thread of the screw sleeve and the major diameter of the inner thread, and the dovetail part of the screw sleeve keyway is located between the minor diameter of the outer thread of the screw sleeve and the major diameter of the inner thread, and the intersection of the dovetail groove and the rectangular groove is lower than the minor diameter of the outer thread, which ensures that the outer thread of the screw sleeve and the inner thread of the base will not interfere during installation, affecting the connection performance; the thread height of the latch that destroys the meshing part is 25-30%, which meets the maximum installation torque of the connection, does not damage the product, and the connection is more stable and reliable.

Description

Technical Field

[0001] The present invention belongs to the technical field of fastener design, and relates to the structural design and application of a plug-type thread insert, in particular to a plug screw insert. Background Art

[0002] The plug screw insert is mainly used to increase the thread strength of the connecting base and repair the thread. By installing the plug screw insert, the plug key destroys the thread connection between the external thread of the screw insert and the base, so that the connecting body is self-locked to achieve the purpose of locking and anti-loosening.

[0003] In the existing plug screw insert, since the guiding part of the plug key is too short, the plug key is easily broken during installation; and the existing keyway size of the screw insert does not match the plug key, resulting in partial pin keys falling off during transportation or use of the assembled plug screw insert; at the same time, the existing transition part structure of the plug key cannot well control the depth of the acting part entering the base, and the die is easily damaged during stamping. Summary of the Invention

[0004] The present invention discloses a plug screw insert according to the deficiencies of the prior art. The purpose of the present invention is to provide a plug screw insert structure with a more reasonable structure and more stable and reliable locking.

[0005] The present invention is achieved through the following technical solutions:

[0006] A plug screw insert, comprising: a tubular screw insert body, an internal thread is provided on the inner wall of the body, an external thread is provided on the outer wall, a plurality of groups of keyways are arranged on the outer wall parallel to the axis of the body, and a plug is arranged in each keyway. The plug is composed of an acting part, a transition part and a guiding part; characterized in that:

[0007] The keyway is composed of a keyway tail part and a keyway rectangular part; the two sides from the guiding part to the transition part of the plug are respectively continuous arc transition structures, and the arc vertices of the two sides are located at the guiding part.

[0008] Further, the maximum width of the guiding part formed between the arc vertices of the two sides of the guiding part is greater than the width of the equal-height part of the keyway, and an interference fit is formed with the insertion of the plug.

[0009] Further, the maximum width of the transition part is greater than the width of the keyway rectangular part to form a pin blocking structure.

[0010] Further, the thickness of the guiding part does not exceed the difference between the minor diameter of the external thread of the screw insert body and the major diameter of the internal thread.

[0011] Further, the keyway tail part is located in the circular ring area formed between the minor diameter of the external thread and the major diameter of the internal thread.

[0012] Furthermore, the thickness of the plug action part is 0.5-2mm, the thread height of the screw sleeve is 0.5-1.5mm, the keyway depth is 0.5-2mm, and the action part destroys 25-30% of the thread height of the meshing part after the screw sleeve external thread is connected with the installation base.

[0013] The length ratio of the guide portion to the action portion of the present invention is 2:3.

[0014] The guide part and the transition part of the present invention are formed by an integral arc R. Compared with other designs, the arc R transition can reduce the wear of the mold and increase the service life. The keyway and the latch on the screw sleeve are matched through the arc R. The maximum width L3 on the guide part is greater than the width L2 of the keyway at the same height. The insertion of the latch forms an interference fit to ensure that the latch and the screw sleeve do not fall off. The transition part forms a stopper pin. The maximum width L of the transition part is greater than the width L1 of the rectangular part of the keyway, ensuring that the latch just sinks the guide part completely into the keyway. At the same time, the position of the screw sleeve screwed into the base is consistent during installation. When the latch is typed into the base during installation, multiple latch keys are stressed at the same time to ensure the stability of the mechanical properties of the product.

[0015] The invention makes interference fit between the height and width of the dovetail groove of the screw sleeve and the latch key, which can effectively prevent the screw sleeve from falling off after assembly. At the same time, the outer contours of the guide part, transition part and action part of the latch key are connected by arc transition, so that the depth of the latch key entering the screw sleeve is consistent during assembly, and the arc transition can protect the mold.

[0016] After the bolt of the present invention is inserted into the screw sleeve, the height h of the guide part does not exceed the difference between the minor diameter of the outer thread of the screw sleeve and the major diameter of the inner thread, so that when the keyway is processed on the screw sleeve, the screw sleeve body will not be damaged and penetrated, the inner thread structure will be damaged, and the connection and installation between the bolt and the screw sleeve will be affected. In addition, the dovetail part of the keyway of the screw sleeve is located between the minor diameter of the outer thread of the screw sleeve and the major diameter of the inner thread, and the intersection of the dovetail groove and the rectangular groove is lower than the minor diameter of the outer thread, which ensures that the outer thread of the screw sleeve and the inner thread of the base will not interfere with each other during installation, thereby affecting the connection performance.

[0017] After installation, the latch of the present invention can damage the threads between the installation base and the screw sleeve to a limited extent, thereby preventing the installation base and the latch screw sleeve from rotating relative to each other and playing an anti-loosening role; the thread height of the meshing part after the latch destroys the connection between the external thread of the screw sleeve and the installation base is 25-30%; the destruction height in this range can meet the maximum installation torque of the corresponding workpiece connection without damaging the product, and at the same time can meet the installation force when the screw sleeve is keyed into the base, thereby reducing the risk of the latch being broken during installation, protecting the installation tool and extending its service life.

[0018] The ratio of the length of the guide portion and the action portion of the latch of the present invention is 2:3. When the length of the action portion meets the product installation performance, the guide portion can meet the guiding function when it is two-thirds of the length of the action portion and the latch will not break during installation.

[0019] The present invention further determines the structural relationship between the keyway of the screw sleeve and the latch, which is more convenient for installation and use, and avoids unqualified installation caused by non-standard assembly; the transition part structure of the latch of the present invention can avoid damage to the mold during production, reducing cost consumption in the production process. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the screw sleeve structure of the present invention;

[0021] Figure 2 It is a front structural perspective view of the screw sleeve body of the present invention;

[0022] Figure 3 It is a schematic diagram of the top view of the screw sleeve body of the present invention;

[0023] Figure 4 This is a schematic diagram of the partial enlarged structure of the keyway of the screw sleeve body of the present invention. Figure 3 The enlarged schematic diagram of the middle part I;

[0024] Figure 5 It is a schematic diagram of the screw sleeve latch structure of the present invention;

[0025] Figure 6 It is a schematic diagram of the front structure of the screw sleeve latch of the present invention;

[0026] Figure 7 It is a schematic diagram of the top view of the screw sleeve latch of the present invention;

[0027] Figure 8 It is a cross-sectional schematic diagram of the threaded sleeve of the present invention in the application and installation state.

[0028] In the figure, 1 is the body, 2 is the internal and external threads, 3 is the keyway, 4 is the pin, 5 is the action part, 6 is the guide part, 7 is the transition part, 71 is the arc segment of the transition part, 8 is the keyway rectangular part, 9 is the keyway dovetail part, M is the major diameter of the external thread, N is the major diameter of the internal thread, M1 is the minor diameter of the external thread, N1 is the minor diameter of the internal thread, L is the maximum width of the transition part, L1 is the width of the rectangular part, L2 is the width of the keyway equal height part, L3 is the maximum width of the guide part, h is the thickness of the guide part, h1 is the thickness of the action part, h3 is the height of the broken thread, R is the arc, and α is the step angle of the transition part. DETAILED DESCRIPTION

[0029] The present invention is further described below in conjunction with specific implementation methods. The specific implementation methods are further descriptions of the principles of the present invention and do not limit the present invention in any way. Technologies that are the same or similar to the present invention do not exceed the scope of protection of the present invention.

[0030] As shown in the figure, the dowel bushing includes: a tubular bushing body 1, with internal threads provided on the inner wall of the body 1 and external threads provided on the outer wall. Multiple groups of keyways 3 are provided on the outer wall parallel to the axis of the body. A dowel 4 is arranged in each keyway 3. The dowel 4 is composed of a working part 5, a transition part 7, and a guiding part 6.

[0031] The keyway 3 is composed of a keyway dovetail part 9 and a keyway rectangular part 8; on both sides of the guiding part 6 to the transition part 7 of the dowel, there are continuous arc R transition structures respectively, and the vertices of the arcs R on both sides are located at the guiding part 6.

[0032] The maximum width L3 of the guiding part formed between the vertices of the arcs R on both sides of the guiding part 6 is greater than the width L2 of the equal-height part of the keyway, and an interference fit is formed when the dowel 4 is inserted.

[0033] The maximum width L of the transition part 7 is greater than the width L1 of the keyway rectangular part 8 to form a stop pin structure.

[0034] The thickness h of the guiding part 6 does not exceed the difference between the minor diameter M1 of the external threads of the bushing body 1 and the major diameter N of the internal threads.

[0035] The keyway dovetail part 9 is located in the circular ring area formed between the minor diameter M1 of the external threads and the major diameter N of the internal threads.

[0036] It is proposed that the thickness h1 of the working part of the dowel 4 is 0.5 - 2 mm, the tooth height of the external threads of the bushing is 0.5 - 1.5 mm, and the keyway depth is 0.5 - 2 mm. The working part 5 destroys 25 - 30% of the thread height at the connection and meshing part of the external threads of the bushing and the installation base.

[0037] In the dowel bushing of the present invention, the length ratio of the guiding part 6 to the working part 5 is 2 to 3.

[0038] Figure 1 It is a schematic diagram of the structure of the bushing in an embodiment of the present invention. As shown in the figure, in the figure, four groups of keyways 3 are symmetrically arranged parallel to the axis of the bushing body 1, and four groups of dowels 4 are correspondingly inserted during installation.

[0039] Figure 2 It is a perspective view of the front structure of the bushing body, Figure 3 It is a schematic diagram of the top view structure of the bushing body, Figure 4 It is a schematic diagram of the partial enlarged structure of the keyway of the bushing body, that is Figure 3 The enlarged schematic diagram of part I in the figure. As shown in the figure, the keyway 3 is composed of a keyway dovetail part 9 and a keyway rectangular part 8. M is the major diameter of the external threads, N is the major diameter of the internal threads, M1 is the minor diameter of the external threads, N1 is the minor diameter of the internal threads, and the keyway dovetail part 9 is located in the area formed by the major diameter N of the internal threads and the minor diameter M1 of the external threads.

[0040] Figure 5 It is a schematic diagram of the dowel structure of the bushing, Figure 6 It is a schematic diagram of the front structure of the dowel of the bushing, Figure 7It is a schematic top view structure diagram of a screw sleeve plug pin; the two sides of the plug pin guiding part 6 to the transition part 7 are respectively continuous arc R transition structures, and the vertices of the arcs R on both sides are located at the guiding part 6. The maximum width L3 of the guiding part formed between the vertices of the arcs R on both sides of the guiding part 6 is greater than the width L2 of the keyway equal-height part, and an interference fit is formed with the insertion of the plug pin 4. The maximum width L of the transition part 7 is greater than the width L1 of the keyway rectangular part 8 to form a stop pin structure, and the thickness h of the guiding part 6 does not exceed the difference between the minor diameter M1 of the external thread of the screw sleeve body 1 and the major diameter N of the internal thread.

[0041] Figure 8 It is a schematic cross-sectional view of the application and installation state of the screw sleeve of the present invention. In the figure, the thread height h3 of the meshing part after the acting part 5 destroys the connection between the external thread of the screw sleeve and the installation base is 25-30%.

Claims

1. A plug screw sleeve, comprising: The tubular screw sleeve body (1) has an internal thread provided on the inner wall of the body (1) and an external thread provided on the outer wall. A plurality of key grooves (3) are provided on the outer wall parallel to the axis of the body. A pin (4) is arranged in each key groove (3). The pin (4) is composed of an acting part (5), a transition part (7) and a guiding part (6). It is characterized in that: The key groove (3) is composed of a key groove tail part (9) and a key groove rectangular part (8). The two sides from the guiding part (6) to the transition part (7) of the pin are respectively continuous arc (R) transition structures, and the vertices of the arcs (R) on both sides are located at the guiding part (6). The maximum width (L3) of the guiding part formed between the vertices of the arcs (R) on both sides of the guiding part (6) is greater than the width (L2) of the equal-height part of the key groove, and the pin (4) is inserted to form an interference fit. The thickness (h) of the guiding part does not exceed the difference between the minor diameter (M1) of the external thread of the screw sleeve body (1) and the major diameter (N) of the internal thread. The maximum width (L) of the transition part is greater than the width (L1) of the key groove rectangular part to form a pin-blocking structure. The key groove tail part (9) is located in the circular ring area formed between the minor diameter (M1) of the external thread and the major diameter (N) of the internal thread.

2. The plug screw sleeve according to claim 1, characterized in that: The thickness (h1) of the acting part of the pin (4) is 0.5 - 2 mm, the tooth height of the external thread of the screw sleeve is 0.5 - 1.5 mm, the depth of the key groove is 0.5 - 2 mm, and the acting part (5) destroys 25 - 30% of the thread height of the connection and meshing part between the external thread of the screw sleeve and the installation matrix.

3. The plug screw sleeve according to claim 1, characterized in that: The length ratio of the above-mentioned guiding part (6) to the acting part (5) is 2 to 3.

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