WEAR PROTECTION CAP AND A BIT HOLDER ARRANGEMENT

Abstract

A wear resistant cap securable to a surface of a bit holder is provided. The wear resistant cap includes a top panel and a side panel. The top panel has a peripheral section enclosing an opening. The forward extension of the top panel, or together with an extension of a side wall at the front, is larger than the rearward extension the top panel. A bit holder arrangement is also provided. The bit holder arrangement includes a bit holder and a wear resistant cap releasably attached to the upper surface of the bit holder.

Claims

1. A wear resistant cap that is securable to a surface of a bit holder, wherein the bit holder is configured to receive a cutting tool, the wear resistant cap comprising: a top panel; and a side panel connected to the top panel, wherein the top panel is configured to cover a top surface of the bit holder, the top panel including a peripheral section enclosing an opening that is configured to receive the cutting tool, and wherein the side panel includes at least one side wall connected to the outer edge of the top panel, and configured to cover at least a portion of a side surface of the bit holder, the top panel including a forward extending portion having a forward extension and a rearward extending portion having a rearward extension, the extensions being defined as a length measured from an inner edge of the peripheral section or a centre of the opening to a forward or rearward edge of the top panel, wherein the forward extension or together with an extension of a side wall at the front, is larger than the rearward extension, the extension of the side wall being defined as a length measured from the top edge to a bottom edge of the side wall.

2. The wear resistant cap as claimed in claim 1, wherein the top panel includes a front portion extending forward beyond the peripheral section, in a generally rectangular or U form with an inner starting edge in an arc form joining the peripheral section.

3. The wear resistant cap as claimed in claim 1, wherein the forward extension, or together with an extension of a side wall at the front, is at least twice as large as the rearward extension.

4. The wear resistant cap as claimed in any claim 1, wherein the side wall at the rearward is tapered inwardly or outwardly in a direction towards the top panel.

5. The wear resistant cap as claimed in any claim 1, wherein the peripheral section has a thickness smaller than a thickness of the rest of the top panel.

6. The wear resistant cap as claimed in any claim 1, wherein at least a part of the side panel has an enlarged thickness than the rest of the wear resistant cap.

7. The wear resistant cap as claimed in any claim 1, wherein at least a part of the side panel includes bulging ribs, arranged in a grid form.

8. The wear resistant cap as claimed in any claim 1, wherein the top panel and the side panel are formed as one integral part, and wherein the peripheral section includes a closed circumferential ring starting in a radius direction from the opening.

9. The wear resistant cap as claimed in claim 1, further comprising a transitional segment situated between the top panel and the side panel, the transitional segment leading from the top panel into the side panel.

10. The wear resistant cap as claimed in claim 1, wherein the side panel extends to a desired length corresponding to a permissible wear distance, wherein the desired length is not less than a radius of the opening.

11. The wear resistant cap as claimed in claim 2, wherein the front portion includes a protrusion in relation to the rear portion of the top panel.

12. A bit holder arrangement for supporting a cutting tool, the bit holder arrangement being securable on a cutter drum of an underground mining machine, the bit holder arrangement comprising: a bit holder, including a base portion and a bit mounting portion located above the base portion, wherein the base portion includes a bottom surface that is configured to be fastenable on the cutter drum, wherein the bit mounting portion includes a bore for receiving the cutting tool, wherein the central axial axis of the bore tilts forward and/or forms an acute angle in relation to the bottom surface, wherein the bit holder includes a top surface from which the bore extends, and a side surface that extends between the bottom surface and the top surface; and a wear resistant cap according to claim 1, the wear resistant cap being attachable to the bit holder, the wear resistant cap being configured to cover the top surface and at least a part of the side surface.

13. The bit holder arrangement as claimed in claim 12, wherein the wear resistant cap is releasably attached to the bit holder by an adhesive material.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0040] A specific implementation of the present application will now be described, by way of example only, and with reference to the accompanying drawings in which:

[0041] FIG. 1 is a top view of a wear resistant cap, according to a specific implementation of the present application;

[0042] FIG. 2 is a side elevation view of the wear resistant cap of FIG. 1;

[0043] FIG. 3 is a cross-section view of the wear resistant cap of FIG. 1 along cross-section A-A of FIG. 1;

[0044] FIG. 4 is perspective view of a bit holder in accordance with one embodiment of the present application;

[0045] FIG. 5 is a side elevation view of a bit holder of FIG. 4;

[0046] FIG. 6 shows a perspective view of a bit holder arrangement having a wear resistant cap in accordance with another embodiment of the present application;

[0047] FIG. 7 shows a perspective view of a bit holder arrangement having a wear resistant cap in accordance with a further embodiment of the present application;

[0048] FIG. 8 is a top view of a wear resistant cap, according to a specific implementation of the present application;

[0049] FIG. 9 is a side elevation view of the wear resistant cap of FIG. 8;

[0050] FIG. 10 is a cross-section view of the wear resistant cap of FIG. 8 along cross-section A-A of FIG. 8;

[0051] FIG. 11 is perspective view of a bit holder in accordance with one embodiment of the present application;

[0052] FIG. 12 is a top view of a wear resistant cap, according to a specific implementation of the present application;

[0053] FIG. 13 is a side elevation view of the wear resistant cap of FIG. 12;

[0054] FIG. 14 is a cross-section view of the wear resistant cap of FIG. 12 along cross-section A-A of FIG. 12;

[0055] FIG. 15 is perspective view of a bit holder in accordance with one embodiment of the present application;

[0056] FIG. 16 shows an existing design of bit holder having wear segments.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT OF THE INVENTION

[0057] Referring to FIGS. 1, 2 and 3, a wear resistant cap 100 is shown in top view (seen along axis z), side elevation view and cross-section view along cross-section A-A, respectively. The cross section A-A passes through the center of the opening 105 of the top panel 101.

[0058] The wear resistant cap is in substantially trumpet-like form and tapered toward the top panel 101.

[0059] The wear resistant cap 100 comprises a top panel 101 and a side panel 102 connected/joined to the top panel; the top panel 101 comprises a peripheral section 103 enclosing an opening 105, the peripheral section 103 has a form of a circumferential ring starting in radial direction immediately from the opening 105, to ensure that no surface portion of the bit holder is exposed from top.

[0060] The side panel 102 comprises a plurality of side walls 106, 108, 109, 111 connected/joined to the outer edge of the top panel, optionally via a transitional segment 107 which is in a form of a bevel; the side walls 106, 108, 109, 111 may be planar or curved plates, for example side wall 108 is concatenated to adjacent side wall 109 at lateral edge 110, in this way the plurality of side walls joining in sequence to form a continuous side protection and form a surrounding closed wall, and configured to cover at least a top portion of the side surface 402 of bit holder. In this embodiment, some side walls like 109, 111 are in curved form.

[0061] The top panel comprises a front portion 104, 801, 1201 extending forward beyond the peripheral section 103 in a generally rectangular or U form with its starting edge in an arc form joining the peripheral section 103.

[0062] The top panel 101 comprises a forward extending portion having a forward extension e1 and a rearward extending portion having a rearward extension e2, said extension is measured from an inner edge of the peripheral section (103) to the forward or rearward edge of the top panel 101 respectively. The extension e3 of a side wall is defined as a length from the upper edge to the bottom edge of the side wall. In particular, it is the length of intersection line of the side wall intersecting with a cutting plane that is through the normal line of the top panel at the center of the opening 105. In this example, the side wall is around 5 mm thick and 50 mm high adapted for a tool shaft having a diameter of 60 mm.

[0063] It is seen that the forward extension e1 together with an extension e3 of a side wall at the front is larger than the rearward extension e2. The side wall at the front includes an opening 112, this opening corresponds, in position and diameter, to a channel 408 in a bit holder 400 for passage of fluid.

[0064] The wear resistant cap 100 is made of a hard material, it is more wear resistant than the material of the bit holder, for example, the cap may be in manganese steel, hardened steel, white iron, or cemented carbide such as HX900. The body of wear resistant cap 100 is made by deep drawing, it is not necessarily be hot formed but may be hot formed.

[0065] In FIGS. 4 and 5, a bit holder is designated by 400, which includes a bore 404 defined by a bore surrounding wall, in which a cutting bit is lead into and is held therein. It has outer flat periphery surface 401, the bit holder 400 can be fixed via bottom surface 405, by means not represented in greater detail, for example, to a cutting roller.

[0066] The bit holder 400 includes a base portion 410 and a bit/sleeve mounting portion 411 located above and supported by the base portion, the bit/sleeve mounting portion includes a surrounding wall to form a generally cylindrical bore which is forward and upward angled/tilted in about 40-60 degree for receiving a cutting bit or sleeve. The bit mounting portion has a top face 401 which is substantially flat, has a forward extension e1. The axial protection depth si is at least 40 mm (see FIG. 5).

[0067] The side surface 403 in the front includes a channel 408 for the supply of pressurized fluid (e.g., oil, water, or oil emulsion, or other fluid), the fluid applies a force against the rear end of the cutting bit or sleeve shank, moving it axially towards the open end, so as to urge a cutting bit or sleeve shank out of the bore 404.

[0068] When it becomes necessary to replace the wear resistant cap, take out the cutting bit or sleeve shank first either manually or by supply of pressurized fluid, and then remove the cap by overcoming the bonding force of the adhesive.

[0069] The bit holder is made of steel, or manganese steel, or chromium molybdenum steel, the wear resistant cap that is releasably attached onto the top panel and upper part of side panel of the bit holder. In the embodiment of FIGS. 1 to 3, the side panel 102 is shown to consist of multiple pieces of wear plates 106, 108, 109 and 111 arranged side by side. The wear resistant cap extends about 50 mm in height from upper edge to lower edge, and 5 mm in thickness.

[0070] FIG. 6 shows a bit holder arrangement having a wear resistant cap, the wear resistant cap is a variant of a wear resistant cap of the embodiment in FIGS. 1 to 3, wherein the cap has similar design as in FIGS. 1 to 3, except that it has an enlarged thickness in a part 601 of the side wall at the rearward and at the left side and at the right side. Part 601 is the applied wear resistant surface.

[0071] FIG. 7 illustrates a further bit holder arrangement having a wear resistant cap, the wear resistant cap is a further variant of a wear resistant cap of the embodiment in FIGS. 1 to 3, wherein the cap has similar design as in FIGS. 1 to 3, except that it includes bulging ribs 701 in a grid form in a part of the side wall at the rearward and at the left side and at the right side. Part 701 is the applied wear resistant grid.

[0072] Referring to FIGS. 8, 9 and 10, a wear resistant cap 800 according to a further embodiment of the present application is shown in top view, side elevation view and cross-section view along cross-section, respectively. It is designed for a second type of bit holder 1100 as shown in FIG. 11, wherein the bit holder has a substantial cylindrical bit receptacle, while the bit receptacle wall is slightly tapered in a direction away from the top surface. The bit holder 1100 differs from that of FIG. 4 in that the top panel has a front portion 801 extending farther forward in relation to the center of the bore. Such front portion may be tapered inwardly as it extends toward the forward edge of the top surface, the front portion is a generally flat. The bit holder 1100 also differs from that of FIG. 4 in that the bit receptacle wall is slightly tapered in a direction away from the top surface rather than tapered in a direction towards the top surface as in FIG. 4.

[0073] To adapt to the shape of the bit holder 1100, the wear resistant cap 800 also has, at the rearward and at the left side and at the right side, a slightly inwardly tapered side wall in a direction away from the top panel. In addition, the front portion 801 of the top panel has enlarged extension along axis x in relation to the design of FIGS. 1 to 3. This allows that the top panel covers at least a part of a base portion of the bit holder. The front portion 801 of the top panel is flat and may have enlarged thickness.

[0074] Referring to FIGS. 12, 13 and 14, a wear resistant cap 1200 according to a further embodiment of the present application is shown in top view, side elevation view and cross-section view along cross-section, respectively. It is designed for a third type of bit holder as shown in FIG. 15, wherein the bit holder has a substantial cylindrical bit receptacle, while the bit receptacle wall is slightly tapered in a direction away from the top surface. The bit holder has a front portion 1201 extending farther forward, like the design of FIG. 11. Such front portion may be tapered inwardly as it extends toward the forward edge of the top surface, the front portion includes a central protrusion 1401 in relation to the rear portion of the top surface.

[0075] To adapt to the shape of the bit holder, the wear resistant cap also has, at the rearward and at the left side and at the right side, a slightly inwardly tapered side wall in a direction away from the top panel. In addition, the front portion 1201 has a convex shape like a saddle in relation to the design of FIGS. 8 to 10, there are arising transitional portions leading the top panel into a ridge 1401. This allows the top panel to conform to the shape of the bit holder and covers at least a part of a base portion of the bit holder.