A hole opener

Abstract

The utility model provides a kind of trepanner, belong to mechanical technical field.It solves the problem of inconvenient operation caused by preventing core clamping, and the problem that hole opening precision is difficult to guarantee.The present trepanner includes the body of lower end open cylindrical shape, the inner peripheral wall of the lower end part of body is provided with protruding part, protruding part is annular and concentrically arranged with body, the center hole wall of protruding part is tapered surface, the inner diameter of protruding part gradually decreases from bottom to top.It has the advantages of preventing core clamping, and enabling staff to conveniently operate, hole opening precision is guaranteed etc..

Description

Technical Field

[0001] This utility model belongs to the field of mechanical technology and relates to a hole opener. Background Technology

[0002] A hole saw is a type of drill bit primarily used to create holes in materials with high surface hardness, such as ceramics, glass, marble, and granite. Existing hole saws typically consist of a cylindrical body with an open bottom. The outer circumference, lower end, and inner circumference of the body are all fixed with a diamond abrasive layer. In use, the hole saw is attached to a tool, and its lower end is perpendicular to the marble slab (or ceramic, glass, granite, etc.). The high-speed rotation of the hole saw, through the diamond abrasive layer, cuts through the marble slab, creating a circular hole. The cylindrical core material cut from the marble is located within the body of the hole saw. Because the hole opener is actually cutting at its lower end, the height of the diamond cutting layer is generally not too high, usually not exceeding half of the body (if the entire outer and inner walls are fixed with the diamond cutting layer, the cost would be very high). This results in a step being formed between the diamond cutting layer and the upper inner hole of the body. In this case, if the core material is discharged into the upper inner hole of the body, it is easy for the core material to get stuck in the body and not be discharged because it is pressed against the step. In this case, the hole opener is scrapped and can no longer be used.

[0003] For this purpose, the applicant previously filed a patent application with patent number 202323020287.8 for an anti-jamming hole opener, which includes a base having a columnar drilled part, an inner hole penetrating one end of the drilled part, a protruding part protruding from the hole wall of the inner hole at the end of the drilled part, the protruding part being arc-shaped and concentrically arranged with the inner hole, and an inner drilling layer being provided on the protruding part and the hole wall of the inner hole. It features a protrusion at one end of the drilled section that penetrates the inner hole, forming an arc shape and concentric with the inner hole. Both the protrusion and the inner hole wall have an inner drilling layer. The thickness of the inner drilling layer at the protrusion is the same as the thickness of the inner drilling layer on the inner hole wall. This ensures that the distance from the inner drilling layer on the arc surface of the protrusion to the center line of the inner hole is less than the distance from the inner drilling layer on the inner hole wall to the center line of the inner hole. In other words, the inner diameter of the fan-shaped ring formed by the inner drilling layer at the protrusion is smaller than the inner diameter of the fan-shaped ring formed by the inner drilling layer on the inner hole wall. In this case, when drilling into marble or granite using this anti-jamming hole saw, the remaining debris is the same diameter as the inner drilling layer at the protrusion location. Clearly, there is a relatively large gap between the remaining debris and the inner wall of the inner drilling layer on the inner hole wall. This large gap allows the remaining debris to be easily discharged without getting stuck in the hole saw and causing blockage.

[0004] As is well known, hole saws operate by high-speed rotation. However, the aforementioned anti-jamming hole saw, due to the presence of its protruding portion, has its center of gravity offset relative to its rotation center. This causes significant radial wobbling during actual processing. This substantial wobbling not only greatly inconveniences the operator during hole-making but also affects the drilling accuracy, leading to hole deformation. To address this, a common technique used by those skilled in the art is to incorporate a weight-reducing groove on the substrate above the protruding portion to ensure that the hole saw's center of gravity does not shift. Utility Model Content

[0005] The purpose of this invention is to address the aforementioned problems in the existing technology by proposing a hole opener that solves the problems of inconvenient operation and difficulty in ensuring hole opening accuracy caused by preventing core jamming.

[0006] The objective of this utility model can be achieved through the following technical solutions:

[0007] An opening device includes a cylindrical body with an opening at the lower end, wherein a protrusion is provided on the inner peripheral wall of the lower end of the body, characterized in that the protrusion is annular and concentrically arranged with the body, the central hole wall of the protrusion is a conical surface, and the inner diameter of the protrusion gradually decreases from bottom to top.

[0008] In practice, a diamond cutting layer is fixed to the lower end of the main body. This diamond cutting layer is located on the outer peripheral wall of the lower end of the main body, the lower end face of the main body, and the central hole wall of the protrusion. As the hole opener rotates at high speed, the diamond cutting layer cuts on the marble slab until the lower end of the hole opener penetrates the lower end of the marble slab, creating a circular hole. The core material cut off from the marble slab due to the hole is located inside the protrusion.

[0009] Because the protrusion is annular, and the central hole wall of the protrusion is conical with its inner diameter gradually decreasing from bottom to top, the diamond-cutting layer fixed to the central hole wall of the protrusion is also of the same shape. This results in the core material cut from the marble slab being truncated cone-shaped, wider at the bottom than the top, while the hole itself is circular. The upward movement of the core material is firmly restricted by the diamond-cutting layer at the central hole wall of the protrusion, preventing it from flowing into the upper inner hole of the main body and forcing it to fall out. This avoids the core material getting stuck inside the main body and rendering the hole saw unusable. Furthermore, because the protrusion is annular, its center of gravity is no longer offset relative to its rotation center. This ensures that the hole saw does not wobble significantly during high-speed rotation, making the hole-making operation easier for workers and ensuring that the hole does not deform, thus improving drilling accuracy.

[0010] In the aforementioned hole opener, the protrusion is uniformly provided with several notches and grooves along the circumference, and the notches and grooves are arranged as straight grooves along the center line direction of the body.

[0011] By designing the notch, the actual contact area between the punch and the core material can be reduced. The smaller the actual contact area, the easier it is for the core material to fall out of the punch.

[0012] In the aforementioned hole opener, the number of notches is three, and the arc of the protrusion between two adjacent notches is 60°.

[0013] The diamond cutting layer is actually formed by bonding diamond abrasive to the main body. Therefore, diamond abrasive will also adhere to the notch / groove to form a diamond cutting layer, although this part does not participate in the cutting process. The curvature of the protrusion between two adjacent notches / grooves is 60°, which means that the curvature of each notch / groove is also 60°. This design ensures that the central hole wall of the protrusion is tapered, while also ensuring that each notch / groove is large enough to allow the diamond abrasive to adhere evenly within it, thus avoiding the situation where the notch / groove is too small and is directly filled by the diamond abrasive.

[0014] In the aforementioned hole opener, a connecting part is provided protruding from the central region of the upper end of the main body, and a threaded connecting hole communicating with the inner hole of the main body is provided in the connecting part.

[0015] With the above settings, this hole saw can be connected to an angle grinder, which can then drive the hole saw to rotate at high speed to make holes.

[0016] Compared to existing technologies, this hole saw features a circular protrusion with a conical central hole wall and an inner diameter that gradually decreases from bottom to top. This means the diamond abrasive layer fixed to the central hole wall of the protrusion also has the same shape. Consequently, the core material cut from the marble slab is shaped like a frustum, wider at the bottom than the top. This effectively restricts the upward movement of the core material, preventing it from being discharged into the upper inner hole of the main body and forcing it to fall out. This avoids the core material getting stuck inside the main body and rendering the hole saw unusable. Furthermore, its center of gravity is no longer offset relative to its rotation center, ensuring that the hole saw does not wobble significantly during high-speed rotation. This makes hole-making operations easier for operators and ensures that the drilled hole does not deform, thus improving drilling accuracy. Attached Figure Description

[0017] Figure 1 This is a cross-sectional schematic diagram of Embodiment 1 of the hole opener.

[0018] Figure 2 This is a cross-sectional view of a hole being made on a board using this hole punch.

[0019] Figure 3 This is a cross-sectional schematic diagram of Embodiment 2 of this hole opener.

[0020] Figure 4 yes Figure 3 Sectional view along the AA direction.

[0021] In the figure, 1 is the main body; 1a is the protrusion; 1a1 is the notch; 1b is the connecting part; 1b1 is the threaded connection hole; and 2 is the diamond cutting layer. Detailed Implementation

[0022] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.

[0023] Example 1

[0024] like Figure 1 As shown, a hole opener includes a cylindrical body 1 with an open lower end. A protrusion 1a is provided on the inner peripheral wall of the lower end of the body 1. The protrusion 1a is annular and concentrically positioned with the body 1, meaning its centerline is collinear with the centerline of the body 1. The central hole wall of the protrusion 1a is conical, and its inner diameter gradually decreases from bottom to top. A diamond abrasive layer 2 is fixedly connected to the lower end of the body 1, and the diamond abrasive layer 2 is located on the outer peripheral wall of the lower end of the body 1, the lower end face of the body 1, and the central hole wall of the protrusion 1a. A connecting portion 1b protrudes from the central region of the upper end of the body 1, and the connecting portion 1b has a threaded connecting hole 1b1 communicating with the inner hole of the body 1.

[0025] In use, the hole saw is installed and fixed to the output shaft of the angle grinder through the threaded connection hole 1b1 on the connecting part 1b. The operator holds the angle grinder with the lower end of the body 1 perpendicularly against the marble slab (or glass, granite, etc.), and then starts the angle grinder to drive the hole saw to rotate at high speed to make a hole. As the hole saw rotates at high speed, the diamond cutting layer 2 cuts on the marble slab until the lower end of the hole saw penetrates the lower end of the marble slab, creating a round hole in the marble slab. The core material cut off from the marble slab due to the hole is located inside the protrusion 1a. At this time, if... Figure 2 As shown.

[0026] Because the protrusion 1a is annular, and the central hole wall of the protrusion 1a is conical with its inner diameter gradually decreasing from bottom to top, the diamond cutting layer 2 on the central hole wall of the protrusion 1a is also of the same shape. This results in the core material cut from the marble slab being truncated cone-shaped, wider at the bottom than the top, while the hole in the marble slab is circular. The upward movement of the core material is firmly restricted by the diamond cutting layer 2 on the central hole wall of the protrusion 1a, preventing it from flowing into the upper inner hole of the body 1 and forcing it to fall out. This avoids the core material getting stuck in the body 1 and rendering the hole opener unusable. Furthermore, because the protrusion 1a is annular, its center of gravity is no longer offset relative to its rotation center. This ensures that the hole opener does not easily wobble during high-speed rotation, making hole opening operations easier for workers and ensuring that the opened hole does not deform, thus improving opening accuracy.

[0027] Example 2

[0028] This embodiment is basically the same as embodiment one in structure and principle, except that: Figure 3 and Figure 4 As shown, in this embodiment, the protrusion 1a is uniformly provided with several notches 1a1 along the circumference, and the notches 1a1 are straight grooves along the center line of the body 1. By providing the notches 1a1, the actual contact area between the hole opener and the core material can be reduced. The smaller the actual contact area, the easier it is for the core material to fall out of the hole opener. There are three notches 1a1, and the arc of the protrusion 1a between two adjacent notches 1a1 is 60°. A diamond cutting layer 2 is also fixedly connected inside the notches 1a1.

[0029] The specific embodiments described herein are merely illustrative examples illustrating the spirit of this utility model. Those skilled in the art to which this utility model pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of this utility model or exceeding the scope defined by the appended claims.

Claims

1. A hole opener, comprising a cylindrical body (1) with an opening at the lower end, wherein the inner peripheral wall of the lower end of the body (1) is provided with a protrusion (1a), characterized in that, The protrusion (1a) is annular and concentrically arranged with the body (1). The central hole wall of the protrusion (1a) is conical, and the inner diameter of the protrusion (1a) gradually decreases from bottom to top.

2. The hole opener according to claim 1, characterized in that, The protrusion (1a) is uniformly provided with a number of notches (1a1) along the circumferential direction, and the notches (1a1) are straight grooves along the center line direction of the body (1).

3. The hole opener according to claim 2, characterized in that, The number of notches (1a1) is three, and the arc of the protrusion (1a) between two adjacent notches (1a1) is 60°.

4. A hole opener according to claim 1, 2, or 3, characterized in that, The upper end of the main body (1) is provided with a connecting part (1b) protruding from the central region, and the connecting part (1b) is provided with a threaded connecting hole (1b1) that communicates with the inner hole of the main body (1).

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