A rear opening type expansion tube and expansion bolt

Abstract

The utility model relates to a kind of bolts, specifically discloses a rear opening type expansion pipe and expansion bolt. The rear opening type expansion pipe in it includes pipe body, the one end of pipe body is front end, the other end is rear end;The pipe body sequentially includes first part and second part from rear end to front end, the first part is provided with expansion groove, the expansion groove is set in the direction perpendicular to pipe body center line and extends to rear end;The second part is solid structure. The rear opening type expansion pipe described above can be reliably expanded and compressed when screw starts to drill, with reliable connection, the advantage of convenient operation.

Description

Technical Field

[0001] This utility model relates to a bolt, specifically to a rear-opening type expansion tube and an expansion bolt. Background Technology

[0002] Expansion bolts are threaded fasteners used to connect equipment to bases such as walls, floors, and boards. Compared to conventional bolts, expansion bolts include an expansion tube. During use, the bolt is screwed into the expansion tube by rotating it. The expansion tube expands and deforms, tightening with the opening in the base, thus providing excellent connection reliability.

[0003] Currently, the expansion tubes of common expansion bolts on the market are usually open in the middle or at the front. After the matching screw is drilled in, the expansion tube needs to be drilled into the grooved area to achieve a good expansion and tightening connection. For example, Chinese utility model patent CN209195894 U discloses a plastic expansion tube with an expansion slot in the middle section, allowing expansion only in the middle section; for example, Chinese utility model patent CN 223136624 U discloses an expansion tube with a slender opening in the middle section and an opening at the front end in the form of an open flap, allowing expansion in the middle and front ends separately.

[0004] However, neither of the aforementioned expansion tubes has an opening in the rear end region, meaning that the rear end region lacks expansion capacity or has a weak expansion capacity. Initially, when the screw aligns with the rear end region during drilling, there is virtually no expansion and tightening effect, and the expansion tube may rotate during the initial drilling phase, affecting screw penetration. Furthermore, when the base thickness is small, the lack of expansion and tightening capacity at the rear end of the expansion tube results in poor connection or even prevents a connection from being achieved. Summary of the Invention

[0005] The technical problem to be solved by this utility model is to provide a rear-opening type expansion tube and expansion bolt, which can reliably expand and tighten when the screw begins to be drilled, and has the advantages of reliable connection and convenient operation.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a rear-opening expansion tube, comprising a tube body, one end of which is the front end and the other end of which is the rear end; the tube body comprises a first section and a second section sequentially from the rear end to the front end, the first section having an expansion groove, the expansion groove being disposed through the tube body in a direction perpendicular to the center line of the tube body and extending to the rear end; the second section being a solid structure.

[0007] During connection, the expansion tube is inserted into the pre-set hole in the base with its front end facing forward. The matching screw is then gradually screwed in from the rear end of the tube. Because the expansion groove extends to the rear end, the expansion tube expands and tightens as soon as the screw is screwed in, ensuring more stable and reliable subsequent drilling operations. Simultaneously, since the expansion groove extends to the rear end of the tube, the effective expansion connection area includes the rear end of the tube. Even for bases with relatively small thicknesses, effective expansion and clamping are possible, accommodating both thick and thin bases. Furthermore, because the second section is a solid structure, it provides overall support to the tube, preventing the tube from dispersing due to the expansion of the expansion groove, thereby improving the reliability of the connection.

[0008] Preferably, the length of the second portion is 1 / 10 to 1 / 7 of the length of the first portion.

[0009] Preferably, an annular retaining ring is provided on the outer side of the rear end of the tube, which can serve as a limiting ring outside the preset hole at the base.

[0010] Preferably, the outer side of the tube is provided with several ribs, which are located near the tail end of the tube and extend to the annular retaining ring. The ribs are not higher than the annular retaining ring.

[0011] Preferably, the first section is divided into two expansion lobes with the expansion groove as the center, and the outer sides of the two expansion lobes are distributed with a number of grooves and protrusions.

[0012] The grooves and bumps can increase the friction between the expansion flap and the base, thereby improving the connection force.

[0013] Preferably, fins are provided on the outer sides of the two expansion lobes, and the fins are inclined toward the rear end.

[0014] The fins can abut against the base to prevent the expansion tube from exiting the base hole.

[0015] Preferably, a guide groove is provided at the rear end of the tube body, the guide groove passing through the center line of the tube body and being perpendicular to the expansion groove.

[0016] The guide groove can guide and center the screw during drilling.

[0017] Preferably, the expansion groove includes a first segment, a second segment, and a third segment along the direction from the rear end to the front end of the pipe body; the first segment and the third segment are aligned and are arranged through the center line of the pipe body; The second segment includes several straight groove segments, with adjacent straight groove segments connected by inclined groove segments. The straight groove segments are parallel to and offset from the center line of the pipe body, and the deviation directions of adjacent straight groove segments from the center line of the pipe body are opposite. The straight groove segments are connected to the first segment by inclined groove segments, and the straight groove segments are connected to the third segment by inclined groove segments.

[0018] As the screw is screwed in along the centerline of the pipe, the first section guides the screw's insertion. Due to the staggered arrangement of the straight groove segments within the second section relative to the pipe's centerline, the expansion flaps have asymmetrical thicknesses in the portions corresponding to the straight groove segments. When the screw is screwed in, the side with the larger thickness expands more, resulting in a greater connection force. Through the alternating distribution of the straight groove segments, several key connection areas can be alternately formed on both sides of the pipe, ensuring an orderly and reliable distribution of tension force along the circumference and axial direction of the pipe.

[0019] Preferably, the two side walls of the third segment are provided with a number of toothed ribs, which are arranged perpendicular to the center line of the tube.

[0020] Toothed ribs can engage with the screw tip after the screw is fully drilled in, improving the connection between the screw tip and the tube body. An expansion bolt includes a screw and a rear-opening expansion tube as described above. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of the rear-opening expansion tube in this embodiment; Figure 2 This is a cross-sectional view of the rear-opening expansion tube in this embodiment; Figure 3 This is a front view of the rear end of the rear-opening expansion tube in this embodiment. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model. Example

[0023] like Figures 1-3 As shown, a rear-opening expansion tube includes a tube body, one end of which is a front end 7, and the other end is a rear end 8. An annular retaining ring 41 is provided on the outer side of the rear end 8 of the tube body, which can function as a limiting device outside a pre-drilled hole at the base. Several ribs 42 are provided on the outer surface of the tube body, located near the rear end of the tube body and extending to the annular retaining ring 41. The ribs 42 are not higher than the annular retaining ring 41.

[0024] like Figures 1-3 As shown, the tube body comprises a first section 5 and a second section 6 sequentially from the rear end 8 to the front end 7, and the second section 6 is a solid structure. Specifically, the length of the second section 6 is 1 / 10 to 1 / 7 of the length of the first section 5.

[0025] like Figures 1-3 As shown, the first section 5 has an expansion groove 1, which penetrates the pipe body perpendicular to the center line and extends to the rear end 8. The rear end 8 of the pipe body has a guide groove 9, which passes through the center line of the pipe body and is perpendicular to the expansion groove 1. The guide groove 9 guides and aligns the screw during drilling.

[0026] like Figures 1-3 As shown, the first section 5 is divided into two expansion petals 2 centered on the expansion groove 1. Several grooves and protrusions are distributed on the outer sides of the two expansion petals 2. The grooves and protrusions increase the friction between the expansion petals 2 and the base, thereby improving the connection force. Specifically, fins 3 are provided on the outer sides of each of the two expansion petals 2, and the fins 3 are inclined towards the rear end 8. The fins 3 can abut against the base, preventing the expansion tube from exiting the base hole.

[0027] During connection, the expansion tube is inserted into the pre-set hole in the base with its front end 7 facing forward. The matching screw is then gradually screwed in from the rear end 8 of the tube. Since the expansion groove 1 extends to the rear end 8, the expansion tube expands and tightens as soon as the screw is screwed in, ensuring a more stable and reliable subsequent drilling operation. Simultaneously, because the expansion groove 1 extends to the rear end 8 of the tube, the effective expansion connection area includes the rear end 8 of the tube. Even for bases with relatively small thicknesses, effective expansion and clamping are possible, accommodating both thick and thin bases. Furthermore, since the second section 6 is a solid structure, it provides overall support to the tube, preventing the tube from dispersing due to the expansion of the expansion groove 1, thereby improving the reliability of the connection.

[0028] like Figures 1-3As shown, further, the expansion groove 1 includes a first segment 11, a second segment, and a third segment 14 along the direction from the rear end 8 to the front end 7 of the pipe body. The first segment 11 and the third segment 14 are aligned and pass through the center line of the pipe body. The second segment includes several straight groove segments 13, with adjacent straight groove segments 13 connected by inclined groove segments 12. The straight groove segments 13 are parallel to and offset from the center line of the pipe body, and the deviation directions of adjacent straight groove segments 13 from the center line of the pipe body are opposite. The straight groove segments 13 are connected to the first segment 11 by inclined groove segments 12, and the straight groove segments 13 are connected to the third segment 14 by inclined groove segments 12. The two side walls of the third segment 14 are respectively provided with several toothed ribs, and the toothed ribs are arranged perpendicular to the center line of the pipe body.

[0029] As the screw is screwed in along the centerline of the pipe, the first segment 11 guides the screw's insertion. Due to the misalignment of the straight groove segment 13 within the second segment relative to the pipe's centerline, the expansion flap 2 has an asymmetrical thickness in the portion corresponding to the straight groove segment 13. When the screw is screwed in, the side with the larger thickness expands more, resulting in a greater connection force. Through the alternating distribution of the straight groove segments 13, several key connection areas can be alternately formed on both sides of the pipe, ensuring an orderly and reliable distribution of tension force along the circumferential and axial directions of the pipe. The toothed ribs can engage with the screw tip after the screw is fully drilled in, improving the connection force between the screw tip and the pipe. An expansion bolt includes a screw and a rear-opening expansion tube as described above.

[0030] In summary, the above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A rear-opening expansion tube, comprising a tube body, wherein one end of the tube body is a front end and the other end is a rear end; characterized in that: The tube body includes a first section and a second section from the rear end to the front end. An expansion groove is provided on the first section. The expansion groove is provided through the tube body in a direction perpendicular to the center line of the tube body and extends to the rear end. The second section is a solid structure.

2. The rear-opening expansion tube according to claim 1, characterized in that: The length of the second part is 1 / 10 to 1 / 7 of the length of the first part.

3. The rear-opening expansion tube according to claim 1, characterized in that: An annular retaining ring is provided on the outer side of the rear end of the tube.

4. The rear-opening expansion tube according to claim 3, characterized in that: The outer side of the tube is provided with several ribs, which are located near the tail end of the tube and extend to the annular retaining ring. The ribs are not higher than the annular retaining ring.

5. The rear-opening expansion tube according to claim 1, characterized in that: The first section is divided into two expansion lobes with the expansion groove as the center, and several grooves and protrusions are distributed on the outer side of the two expansion lobes.

6. The rear-opening expansion tube according to claim 5, characterized in that: The outer sides of the two expansion lobes are respectively provided with fins, and the fins are inclined towards the rear end.

7. The rear-opening expansion tube according to claim 1, characterized in that: The rear end of the tube is provided with a guide groove, which passes through the center line of the tube and is perpendicular to the expansion groove.

8. The rear-opening expansion tube according to any one of claims 1-7, characterized in that: The expansion groove includes a first segment, a second segment, and a third segment along the direction from the rear end to the front end of the pipe body; the first segment and the third segment are aligned and are set through the center line of the pipe body; The second segment includes several straight groove segments, with adjacent straight groove segments connected by inclined groove segments. The straight groove segments are parallel to and offset from the center line of the pipe body, and the deviation directions of adjacent straight groove segments from the center line of the pipe body are opposite. The straight groove segments are connected to the first segment by inclined groove segments, and the straight groove segments are connected to the third segment by inclined groove segments.

9. The rear-opening expansion tube according to claim 8, characterized in that: The two side walls of the third segment are respectively provided with a number of toothed ribs, which are arranged perpendicular to the center line of the tube.

10. An expansion bolt, characterized in that: Includes screws and rear-opening expansion tubes as described in any one of claims 1-9.

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