CHISEL WITH DOUBLE LIMIT DISCS

Abstract

Disclosed is a chisel with double limit discs. The chisel includes a holding seat and a bit mounted on the holding seat, the bit including a head and an extension provided on the lower side of the head, a first limit disc and a second limit disc arranged up and down are mounted between the holding seat and the head, the middle of the first limit disc having a first mounting through hole, and the middle of the second limit disc having a second mounting through hole, the second limit disc being partially concaved or partially convexed with the first limit disc. For the chisel, the service life of the holding seat and the bit are prolonged, the coaxiality between the chisel position and the holding seat position is maximized guaranteed, and the chisel may maintain the optimal rotary cutting performance during operation.

Claims

1. A chisel (5) with double limit discs, comprising a holding seat (3) and a bit mounted on the holding seat (3), the bit comprising a head (7) and an extension (8) provided on the lower side of the head (7), the bottom of the head (7) having a head support surface (7.1), and the upper end surface of the holding seat (3) having a stress surface (3.4), wherein, a first limit disc (1) and a second limit disc (2) arranged up and down are mounted between the holding seat (3) and the head (7), the middle of the first limit disc (1) having a first mounting through hole (10), and the middle of the second limit disc (2) having a second mounting through hole (20), the second limit disc (2) being partially concaved or partially convexed with the first limit disc (1); the extension (8) passes through the first mounting through hole (10) and the second mounting through hole (20).

2. The chisel (5) of claim 1, wherein, the second limit disc (2) is partially concaved with the first limit disc (1); the lower side of the first limit disc (1) has a lower surface (1.5) and a positioning portion (1.4), the positioning portion (1.4) being an annular convex arranged on the lower edge of the first mounting through hole (10); the upper side of the second limit disc (2) has a force guide surface (2.1) and a guide portion (2.2), the guide portion (2.2) being an annular concave arranged along the upper edge of the second mounting through hole (20); the lower surface of the second limit disc (2) has an annular support surface (2.6).

3. The chisel (5) of claim 2, wherein, the positioning portion (1.4) of the first limit disc (1) is matched with the guide portion (2.2) of the second limit disc (2).

4. The chisel (5) of claim 3, wherein, a central axis L1 of the first mounting through hole (10) coincides with a central axis L2 of the second mounting through hole (20); the first limit disc (1) and the second limit disc (2) are freely rotatable with each other around the central axis L1 or L2.

5. The chisel (5) of claim 4, wherein, the first mounting through hole (10) is the same as the second mounting through hole (20) in diameter, and the first mounting through hole (10) and the second mounting through hole (20) are matched with an extension (8) of the chisel (5).

6. The chisel (5) of claim 2, wherein, the upper surface (1.1) of the first limit disc (1) is in contact with the head support surface (7.1) of the chisel (5); the lower surface (1.5) of the first limit disc (1) is in contact with the force guide surface (2.1) of the second limit disc (2), and the support surface (2.6) of the second limit disc (2) is in contact with the stress surface (3.4) of the holding seat (3).

7. The chisel (5) of claim 6, wherein, the lower side of the second limit disc (2) is provided with a concave portion (2.7) along the second mounting through hole (20), the concave portion (2.7) comprises an inner upper limit surface (2.4) and an outer sloped transition surface (2.5).

8. The chisel (5) of claim 7, wherein, the upper end surface of the holding seat (3) has a support portion (3.1) with an annular convex, the support portion (3.1) is matched embedded in the concave portion (2.7), and there is a clearance between the support portion (3.1) and the concave portion (2.7).

9. The chisel (5) of claim 6, wherein, the lower side of the second limit disc (2) is provided with a convex portion (2.7′) along the second installation through hole (20), the upper end surface of the holding seat (3) has a concave support portion, the convex portion (2.7′) is matched embedded in the support portion, and there is a clearance between the convex portion (2.7′) and the support portion.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] FIG. 1 is a semi-sectional view of a chisel with double limit discs mounted in a holding seat in the disclosure;

[0017] FIG. 2 is an enlarged view of a partial sectional view A in FIG. 1;

[0018] FIG. 3 is a side full sectional view of a combined structure of a first limit disc and a second limit disc in FIG. 1;

[0019] FIG. 4 is an exploded view of a combined structure of a first limit disc and a second limit disc in FIG. 1;

[0020] FIG. 5 is a schematic diagram of an upper structure of a combined structure of a first limit disc and a second limit disc in FIG. 1;

[0021] FIG. 6 is a schematic diagram of a bottom structure of a combined structure of a first limit disc and a second limit disc in FIG. 1;

[0022] FIG. 7 is a side full sectional view of another embodiment of the disclosure.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0023] FIGS. 1 and 2 illustrate a front side view of a chisel 5 with double limit discs mounted in a holding seat 3. The chisel 5 includes a top 6 made of tungsten-cobalt-based cemented carbide and permanently fixed in a blind hole-shaped molten pool of a chisel head 7 by brazing. The chisel extension 8 extends below the chisel head 7 and is formed by a cylinder with a diameter less than that of the chisel head 7. A first limit disc 1 and a second limit disc 2 are sleeved on the holding portion 8.1 of the chisel extension 8, the upper surface 1.1 of the first limit disc 1 is against the support surface 7.1 of the chisel head 7, and the support surface 2.6 of the second limit disc 2 is against the convex torus 3.2 of the holding seat 3. The steel fastening sleeve 4 is usually rolled by a thin steel sheet, with certain elasticity, is provided with an opening, with an appropriate length, and is sleeved on a second holding handle 8.2 of the chisel extension 8. A plurality of inner recesses 4.1 are processed on the surface using a stamping process and matched in the groove 8.3 of the holding handle, the steel fastening sleeve 4 is pressed into the mounting through hole 30 of the holding seat 3, and the outer side surface is expanded and pressed into the mounting through hole 30 of the holding seat 3 by maintaining fixed contact.

[0024] FIG. 2 enlarges a partial sectional view A in FIG. 1, in which the first limit disc 1, the second limit disc 2, the holding seat 3 and the steel fastening sleeve 4 are shown in a semi-sectional view. As illustrated in FIG. 2, in the actual working state, the concave portion 2.7 of the limit disc 2 is configured to be engaged with the support portion 3.1 of the holding seat 3. The upper limit surface 2.4 is in a clearance fit state with the convex torus 3.2, the clearance value being within 0.4 mm to 2.9 mm, and the transition surface 2.5 is in a clearance fit state with the guide surface 3.3, and the support surface 2.6 is in contact fit with the stress surface 3.4, which eliminates dimension errors due to machining. In the working process, it may be deemed that the holding seat 3 is relatively stationary, when the first limit disc 1 and the second limit disc 2 are rotated around the holding seat 3, the central axes L1 and L2 of the first limit disc 1 and the second limit dis 2 are rotated around the central axis L of the holding seat 3.

[0025] Then as illustrated in FIGS. 1 and 2, the support portion 3.1 of the holding seat 3 extends out from one side of the stress surface 3.4 to form a circular boss shape, with the convex torus 3.2 as a termination surface in the length direction and the guide surface 3.2 as a termination surface in the diameter direction, and form a mounting through hole 30 around the central axis L of the holding portion 3 for a steel fastening sleeve 4 for accommodating a chisel 5, a second holding handle 8.2 and a third holding handle 8.3.

[0026] As can be seen from FIGS. 2 to 6, a first holding handle 8.1 of the extension 8 of the chisel 5 has a diameter d1 ranging from 15 mm to 25 mm. The first limit disc 1 has a mounting through hole 10 having a diameter D1 ranging from 16 mm to 26 mm; the second limit disc 2 has a mounting through hole 20 having a diameter D2 ranging from 16 mm to 26 mm, and the first holding handle 8.1 of the extension 8 of the chisel 5 is mounted in the mounting through holes 10 and 20 of the first limit disc 1 and the second limit disc 2. The positioning portion 1.4 of the first limit disc 1 is interlocked with the guide portion 2.2 of the second limit disc 2. The lower surface 1.5 of the first limit disc 1 is configured in contact fit with the force guide surface 2.1 of the second limit disc 2. The central axis L1 of the mounting through hole 10 of the first limit disc 1 is arranged coaxially with the central axis L2 of the mounting through hole 20 of the second limit disc 2. The first limit disc 1 and the second limit disc 2 are freely rotatable with each other around the central axis L1. The concave portion c of the second limit disc 2 is formed by surrounding the upper limit surface 2.4 and the transition surface 2.5. By such a design, the chisel 5 maintains coaxiality with the central axis L of the holding seat 3 to the greatest extent during a rotation process, to improve the use performance and service life of the chisel 5.

[0027] The chisel 5 needs to keep rotating at high speed in the mounting through hole 30 of the holding seat 3. For this purpose, the chisel 5 needs to maintain coaxiality with the central axis L1 of the holding seat 3 to the greatest extent during a rotation process, which is beneficial to improving the use performance of the chisel 5, therefore, the first limit disc 1 and the second limit disc 2 may increase the contact area of the limit disc and the holding seat, reduce the mutual pressure force, and prolong the service life of a chisel and a holding seat, and achieve the beneficial effects of the disclosure.

Embodiment 2

[0028] Similar to Embodiment 1, the difference relies on that the lower side of the second limit disc is provided with a convex portion 2.7' along the second mounting through hole, in this case, the upper end surface of the holding seat has a concave support portion, the convex portion is matched embedded in the support portion, and there is a clearance between the convex portion and the support portion.

[0029] It should be noted that, the attached drawings of the embodiments are all in a very simplified form and use inaccurate ratios, and are only used for assisting in explaining embodiments of the disclosure conveniently and clearly.

[0030] Although an implementation solution of the disclosure has been disclosed as above, it is not limited to the applications listed in description and implementation, and may be applied to various fields suitable for the disclosure. Additional changes may be easily made for those skilled in the art. Therefore, the disclosure is not limited to specific details and illustrations shown and described herein without departing from the general concepts defined by appended claims and equivalent scopes.