WO2013021282A2 - Rotary cutter drum - Google Patents

Abstract

A rotary cutter drum (1) that includes a barrel (2) around the external periphery (3) of which is welded at least one helical vane (4). A multiple of notches (5) are provided at locations where a mineral cutting tool (S) is required. Each notch (5) receives a portion of a tool holder (6), which is welded in place. The tool holder (6) provides an aperture to receive, and releasably retain, the shank (7) of a mineral cutting tool (8), with the terminal end (16) of the shank (7) being exposed. Each notch (5) has an opening (15A) opposite the exposed, terminal end (16) of a shank (7). The opening (15A) has an extended length toward the barrel (2), by a distance at least approximating to the length of the shank to define a shank-receiving void or chamber.

Description

Title of the Invention

Rotary Cutter Drum

Priority

This application claims the benefit of British Application Serial No. 1113669.4 field August 9, 2011.

Field of the Invention

This invention relates to a rotary cutter drum, primarily for use in mineral winning, such as coal mining, but also useable for other underground purposes such as tunnel or roadway driving, or above ground for civil engineering works, such as road planing, trench cutting, both on land and sub-sea.

Background of the Invention

In coal etc mining by the longwall technique, it is conventional to provide steel roof supports either as components of a series of hydraulically powered roof supports extending along, and advanceable with, the mineral face as the latter is extracted, or permanent supports in the form of rings or arches spaced along roadways that are conventionally provided at each end of a longwall face.

Mineral is removed by a single or double ended ranging drum shearer, which traverses the mineral face, with a rotary cutting drum carried by the, or each, ranging arm to follow the mineral seam, each drum being provided with 50-100 cutting tools, each having a tungsten carbide tipped head or blade and an integral shank by which each tool is replaceably located in a tool holder. However, despite the best efforts of the operatives, the drums, and specifically the tools, frequently strike a steel roof bar or hard inclusions in the roof and floor of the mineral seam, and the tool is fractured - typically its head or blade is sheared from its shank.

Cutting tools need regular replacement when the tungsten carbide tip is worn or damaged, or when the head or blade of a cutting tool is missing. However, removal of a broken or damaged cutting tool is frequently difficult or sometimes impossible, such that removal cannot be effected until the drum is eventually taken to the surface, or a safe underground area, for refurbishment.

In civil engineering works, the cutting tool may strike an unknown buried obstruction such as concrete reinforcement bar, a steel railway line, etc.

In a known arrangement, both the vanes and end plates are provided with multiple notches at locations where a cutting tool is required. Each notch receives a tool holder, which is welded in place. A smaller dimensioned opening extends from each notch, opposite an exposed end of the shank of an inserted cutting tool, so that one end of a lever or drift may be inserted into the opening to engage the exposed end to prise a cutting tool from its tool holder in a radially outward direction. Whilst satisfactory for unbroken cutting tools, it is virtually impossible to remove a residual shank by this method. In detail, for a shank of say 100mm length, the second notch is 20-30mm length. Object of the Invention

A basic object of the present invention is the provision of an improved rotary cutter drum.

Summary of the Invention

In accordance with one aspect of the invention, a rotary cutter drum includes a barrel and at least one helical vane secured to the barrel. Each vane includes a plurality of notches at locations where a cutting tool is required. A tool holder is secured into each notch. The tool holders each include an aperture to receive and re!easably retain a shank of the cutting tool. The aperture extends through the tool holder such that a terminal end of the shank is exposed. Each vane has an opening that communicates with each notch where the exposed terminal end of the shank is located. Each of the openings extends toward the barrel by a distance at least the length of the shank for receiving the shank to accommodate removal of the shank from the tool holder in an inward direction.

In one preferred application, the present invention pertains to a rotary mineral cutter drum comprising a barrel around the external periphery of which is welded at least one helical vane, with an end plate provided at one end of the barrel. The end plate and the vane(s) are provided with multiple notches at locations where a mineral cutting tool is required. Each notch receives a portion of a tool holder, which is welded in place. The tool holder provides an aperture to receive, and releasably retain, the shank of a mineral cutting tool, with the terminal end of the shank being exposed. Each notch has a smaller opening opposite where an exposed, terminal end of a shank will be located. Each opening is extended toward the barrel by a distance approximating the length of the shank to define a shank-receiving void or chamber.

Advantages of the Invention

By providing an extended opening in the vane below the notch to define a shank-receiving void, the remains of a shank may be removed from the tool holder in the opposite direction (radially inwardly) to that conventionally used for tool removal (radially outwardly). The use of a hammer and punch to knock the remains of the broken shank into the opening is easier and quicker in most cases than prying the tool out of the tool holder in an outward direction. Moreover, in circumstances of removing a tool with a lost blade or head, i.e., removing the remains of a broken, damaged or jammed cutting tool, and specifically its shank, can be facilitated with the present invention without requiring the drum to be taken out of service.

in one example, the cutting tool has a 100mm long shank, the opening extends to at least 100mm below the tool holder.

Brief Description of the Drawings

The invention is further explained and exemplified in the accompanying drawings in which:

Figure 1 is a portion of a rotary, mineral cutter drum, and specifically one of Applicants prior art shearer cutting tools inserted into one of Applicants prior art tool holders welded into a notch of a helical vane or end plate, and provided with a second notch of normal, industry-standard length, typically 25% of the shank length; and Figure 2 corresponds to Figure 1, but shows a rotary cutting drum in accordance with the invention, provided with an opening that has a substantial extension of its length beyond the second notch of the prior art to at least 100% of the shank length, to define a shank receiving void or chamber, into which a headless shank may be knocked, radially inwardly, with the broken shank then pushed or tapped out of one side or the other of the chamber.

Detailed Description of the Drawings

In both Figures 1 and 2, like components are accorded like reference numerals. A rotary mineral cutter drum 1 comprises a barrel 2, having an external periphery 3 around which is welded at least one helical vane 4, with an end plate (not shown) at one end of the drum, in a well-known manner. Also as known the, or each, vane is provided with multiple and generally square U-shaped notches 5 (though the notches could have other shapes), each to receive a portion of a tool holder 6 which is welded in position; other means for securing a tool holder to a vane are possible. Each tool holder 6 is provided with a rectangular aperture (not shown) to receive a correspondingly rectangular shank 7 of a mineral cutting tool 8 provided with an integral head or blade 9 extending from seating surfaces 10 engaging abutment surfaces 11 of the tool holder 6. While rectangular apertures and shanks are common, other shapes could be used. An industry-standard latching arrangement (not shown) is used to prevent inadvertent loss of the cutting tool 8 from its holder 6 during rotation of the drum 1. The blade 9 is also provided with a notch 12, defined by nose 13, for engagement by a screwdriver or other lever to prise the cutting tool 8 from its holder 6 when changing of cutting tools is required. The blade 9 ordinarily includes a carbide tip 14.

In a standard drum, it is frequently not possible to extract a pick 8 by engaging the notch 12. The cutting tool 8 can, for instance, become jammed in its holder due to tight tolerances between shank dimensions and receiving aperture dimensions, and/or as a result of impactions in service with resultant metal deformation, and/or rusting between engaging surfaces compounded by the latching device deliberately resisting extraction. Further, the nose 14 could be damaged or missing, such that the notch 12 no longer exists yet the cutting tool 8 remains in place. To deal with this situation to enable the cutting tool to be removed, a second, shank access notch 15 of relatively small dimensions has been provided beneath the tool holder 6, so that the end of a lever may be engaged in the second notch 15 to gain access to the exposed, terminal end 16 of the shank 7, to prise the cutting tool 8 radially from its holder 6. Conventionally, the second notch 15 has a length 17 approximating to some 25% of the length 18 or the shank 7.

However, if the blade 9 has been broken from its shank 7, it is virtually impossible to remove the remains of the shank in the standard drum. As a result, no replacement cutting tool 8 can be inserted until such time, if coal mining is involved, that the drum can be removed from its coal winning machine and taken to the surface, or to a safe area, where welding operations can be effected to remove the tool holder 6, then knock out the remains of the shank 7, and then weld the box back onto the vane 4. The above is the situation depicted in Figure 1 showing the prior art arrangement.

The arrangement in accordance with the invention is depicted in Figure 2, where an opening 15A extends radially inwardly toward the barrel 2 by a length 17A which approximates (or is longer) to the length IS of the shank 7; preferably length 17A is slightly in excess of the length of the shank 7. The extended length of opening 15A defines a shank receiving void. Accordingly, in circumstances of a broken off blade 9, the remains of the shank 7 can be extracted radially inwardly, instead of, conventionally, radially outwardly, by engaging the top of the shank 7 with a punch or chisel and hammering the remains out of its receiving aperture in the holder 6 and into the shank receiving void or chamber, defined by the extended length of opening ISA. It follows that with a means of extracting the remains of the shank of a broken cutting tool 8, a replacement cutting tool S can readily be inserted in the now empty holder 6, and removal of the drum 1 from the machine is unnecessary. It will be appreciated that, with rotary mineral cutter drums 1 of conventional configuration, a small number of pickless tool holders 6 can be tolerated, as a typical drum has 70-100 or more tool holders and cutting tools, but eventually, premature removal of a drum from its machine, with attendant loss of production becomes unavoidable with prior art drums generally as depicted in Figure 1. A drum 1 in accordance with the invention and as depicted in Figure 2 will avoid this drawback.

Claims

1. A rotary cutter drum comprising a barrel, at least one helical vane secured to the barrel, each said vane including a plurality of notches at locations where a cutting tool is provided, a tool holder secured into each said notch, the tool holder including an aperture to receive and releasably retain a shank of the cutting tool, the aperture extending through the tool holder such that a terminal end of the shank is exposed, and an opening communicating with each said notch where the exposed terminal end of the shank is located, each said opening extending beyond the tool holder, toward the barrel, by a distance at least the length of the shank for receiving the shank and accommodating removal of the shank from the tool holder in an inward direction .

2. A drum as claimed in Claim 1 wherein the opening extends beyond the tool holder at least 100mm.

3. A drum as claimed in Claim 1 wherein a plurality of said vanes are secured to the barrel.