Guide shoe for a cutting machine

The guide shoe according to the invention for cutting machines with a pintype drive has an insertion pocket in which a coupling piece engages from above, which coupling piece is arranged on a guide arm of the cutting machine and to which the guide shoe is attached so as to be pivotable by means of a transverse bolt which passes through the insertion pocket. In order also to allow the guide shoe to be pivotable about a vertical axis, the coupling piece is provided with an upright vertical journal which engages from below in a corresponding bearing hole on the guide arm. In this case, in a preferred embodiment, the bearing journal is decoupled from transverse forces which are transmitted between the guide arm and the guide shoe via a transverse-force piece arranged on the coupling piece.

FIELD OF THE INVENTION 
The invention relates to a guide shoe for a cutting machine, especially for 
a drum shearer which is also often referred to as a coal auger, which 
cutting machine runs above a conveyor and can be moved along the conveyor 
by means of a pin-type drive, the guide shoe being of the type to be 
connected to a guide arm of the cutting machine so that it can pivot about 
a transverse bolt, and the guide shoe having a guide projection which 
interacts with a guide strip on the conveyor. 
BACKGROUND OF THE INVENTION 
As is well known, cutting machines often referred to as coal augers or drum 
shearers are used worldwide in mining operations for excavating coal 
seams. They are used in underground workings together with a conveyor, 
designed as a chain conveyor, which can be advanced in the direction of 
excavation and are designed in such a way that they straddle the conveyor 
in the manner of a portal with their machine body. In this case, the 
cutting machines are supported and guided on both sides of the conveyor on 
guide rails arranged on the conveyor. 
The modern cutting machines are moved along the conveyor with the aid of a 
pin-type drive during their excavation run. In this case, it is usual to 
arrange a pin drive element on the side remote from the coal face, i.e. on 
the stowing side of the conveyor, which element comprises toothed or 
pin-type racks or preferably a pin drive chain. In this case, the cutting 
machine has at least one gearwheel or pin wheel which is driven by a drive 
and engages in the pin-type rack mounted on the conveyor or in the 
horizontal chain links of the pin drive chain (DE-C-25 30 754, DE-A-29 38 
446, FR-C 2 523 639). 
It is usual to guide the cutting machine on that side (generally the 
stowing side) of the conveyor where the pin drive element or the pin drive 
chain is located by means of guide shoes on guide strips which, in this 
case, are attached laterally to the conveyor, machine guiding in the 
vertical and lateral direction being brought about with the aid of the 
guide shoes. In this case, it is also known to attach the guide shoes to 
the cutting machine or to guide arms thereof by means of horizontal 
transverse bolts so that they can pivot up about the bolt to a limited 
extent, so that they are capable of adapting to the path of the conveyor 
which is usually not horizontal. In this case, guide shoes are used, for 
example, which engage around the pin-type racks from above and below 
approximately in the manner of a hook, and which are attached to the 
cutting machine or its machine body with spacing above the pin-type racks 
so as to be pivotable about the horizontal transverse bolts (DE-C-25 52 
085, DE-C-26 26 291, DE-A-29 25 240). However, it is also known to attach 
bearing rails to the conveyor on the stowing side, in which rails the pin 
drive chain is disposed, and which at the same time form guide strips for 
the guide shoes (FR-C 2 523 639). 
A disadvantage of these known arrangements is that, although the guide 
shoe, as a result of its pivotability about the transverse bolt, provides 
compensation when the floor is not flat, the guide shoe can nevertheless 
become clamped on the guide strip while the cutting machine is moving, if 
the guide strip does not extend precisely in a straight line, but assumes 
a slightly curved course, for example when advancing the individual 
conveyor pans of the conveyor. In this case, constraining forces may occur 
between the guide shoe and the guide strip, which forces are transmitted 
to the cutting machine and result in increased wear. 
SUMMARY OF THE INVENTION 
Starting from the abovementioned prior art, which is incorporated herein by 
reference, the invention is mainly based on the object of providing a 
guide shoe for cutting machines, e.g. rolling cutting machines, which 
permits secure and precise guiding of the cutting machine along the guide 
strip without any jamming or the like occurring in the process and thus 
ensuring both good vertical and good horizontal guiding of the cutting 
machine. 
It is therefore proposed to make the guide shoe connectable to the guide 
arm so as to be rotatable or pivotable about a vertical axis. In this way, 
preferably a universal joint-type connection, provided by a combination of 
the transverse bolt and an additional vertical journal, is provided 
between the guide shoe and the guide arm. 
The guide shoe can thus not only be pivoted about the transverse bolt about 
a horizontal axis, but pivoting about the vertical axis is additionally 
made possible, so that, in the event of a slightly curved course of the 
guide rail, for example when the conveyor pans of the conveyor do not lie 
in a straight line, the guide shoe can adapt to the said course, and no 
jamming occurs between the guide shoe and the guide strip. In this way, 
the wear of the parts can be reduced substantially. 
It is particularly expedient if the vertical journal is arranged on an 
approximately plate-shaped coupling piece which is arranged in an 
insertion pocket on the guide shoe so as to be pivotable by means of the 
transverse bolt. 
In this embodiment of the guide shoe in which the coupling piece is bounded 
circumferentially and at the bottom by wall parts of the insertion pocket, 
a good seat results as does reliable pivoting displacement of the guide 
shoe on the guide arm of the cutting machine both about the horizontal 
axis of the transverse bolt and about the vertical axis. This also enables 
the bolt joint for the transverse bolt, at the same time, be arranged at a 
particularly low level on the guide shoe, which results in particularly 
good and reliable guiding of the cutting machine by means of the guide 
shoes attached to it during cutting machine operation. For this purpose, 
the guide shoe furthermore preferably has, on its bottom, a preferably 
central bottom opening for the engagement of the coupling piece, thus 
making it possible for the joint connection for the transverse bolt to be 
arranged at a particularly low level. 
A particularly advantageous refinement results if the coupling piece is 
provided with a transverse-force piece which engages in a cutout on the 
guide arm. Such a design results in the vertical journal only taking on 
the function of a hinge and not having to absorb any forces transversely 
to its axis of rotation, all of which forces are transmitted between the 
guide arm and the guide shoe by the transverse-force piece. The vertical 
journal can thus be dimensioned to be comparatively weak without this 
possibly leading to the journal becoming damaged or even broken off if the 
guide shoe in the guide strip bumps against an obstacle, such as, for 
example, a boulder, and thus inhibited briefly in its free movement. 
On its end faces which receive transverse forces, the transverse-force 
piece is preferably designed to be approximately convex with a centre of 
curvature in the axis of the vertical journal. It can thus pivot freely in 
the cutout on the guide arm while always resting against the front and 
rear contact surfaces of the cutout in the direction of movement of the 
cutting machine, so that the force transmission via the transverse-force 
piece is always ensured irrespective of the angular position of the guide 
shoe in relation to the guide arm. 
It is particularly advantageous if the transverse-force piece projects 
beyond the coupling piece at its end face, and holding webs arranged on 
the guide arm engage below the said transverse-force piece. The holding 
webs engaging below the transverse-force piece effectively prevent the 
guide shoe from dropping down out of the guide arm, and thus bring about a 
positive-locking connection of the two components, but without impeding 
the free pivotability of the vertical journal in the associated bearing 
hole on the guide arm. 
The cutout for the transverse-force piece can be designed to be essentially 
rectangular, while the transverse-force piece has an approximately 
trapezoidal design which tapers in the direction of the end faces. With 
small dimensions of the guide arm and the transverse-force piece, this 
refinement ensures sufficient pivotability which usually does not need to 
be greater than 5 to 10.degree.. On its contact faces facing the end faces 
of the transverse-force piece, the cutout may have a concave curvature 
with a radius of curvature which corresponds approximately to the radius 
of curvature of the end faces of the transverse-force piece. As a result, 
the transverse-force piece is always in flat contact with the guide arm in 
the cutout, irrespective of its angular position, so that the surface 
pressures between these two components is comparatively low. 
A particularly advantageous refinement results if the cutout is designed to 
be open laterally to the direction of travel of the cutting machine. In 
such an arrangement, the guide shoe can be mounted on the guide arm in a 
particularly simple manner, in that, having been rotated through about 
90.degree. relative to its direction of travel, it is inserted from below 
with the vertical journal into the corresponding bearing hole on the guide 
arm and is then pivoted into its direction of travel, the holding webs 
engaging below the transverse-force piece and thus securing the guide shoe 
against dropping out. 
The coupling piece can have a convexly curved shaped-out portion which, in 
the coupling state, is inserted into the bottom opening, and the inner 
surfaces of the parallel side walls of the insertion pocket can form 
vertically disposed flat contact surfaces for the plate-shaped coupling 
piece. In this case, the width of the insertion pocket is closely adapted 
to the width of the coupling piece, so that the latter has a good lateral 
support in the guide shoe, that is to say the coupling piece is mounted 
essentially without play on the transverse bolt, thus resulting in a good 
lateral support of the guide shoe on the guide arm. The guide shoe is 
preferably mounted on the guide arm with a pivoting restriction. 
Further features and advantages of the invention emerge from the following 
description and the drawings in which an embodiment of the invention is 
explained in greater detail using an example.

DETAILED DESCRIPTION OT THE EMBODIMENT 
FIG. 1 shows a very diagrammatic overview drawing of a cutting machine 
system which is generally of the known type with a cutting machine 1 and a 
conveyor 2 which, in underground working, is arranged on the floor 3 in 
front of the coal face (not illustrated). Of the cutting machine 1, 
essentially only its machine body 4 is shown, which straddles the conveyor 
2 in the manner of a portal and is supported on one side of the conveyor 
(coal face side) by means of running rollers 5 or else sliding runners on 
a running rail 6 which is fixedly arranged laterally on the conveyor 2. On 
the opposite side (stowing side) in the region of each of its two ends, 
the machine body 4 has a guide arm 7, to whose lower end a guide shoe 8 is 
pivotably attached, which is guided on a guide strip 9. On its machine 
body 4, the cutting machine 1 has a drive with at least one driven 
gearwheel or pin wheel 10 which meshes with a pin drive chain 11 mounted 
on a bearing rail 12. In the exemplary embodiment shown, the bearing rail 
12 also forms the guide strip 9. It is fixedly arranged on brackets 13 
which are attached to the conveyor 2 on the stowing side. 
The conveyor 2 comprises in the usual way a chain conveyor whose conveying 
port is composed of individual conveying chutes or conveyor pans which are 
each connected to each other with slight vertical and horizontal 
articulation. 
Numerous configurations of cutting machine systems of the general design 
described above or similar designs are known and have been in use for many 
years. The present invention lies in the design and arrangement of the 
guide shoes 8 of the cutting machine. 
As shown in FIGS. 2 and 5, the integrally designed guide shoe 8 has an 
approximately slot-like insertion pocket 14 which is open on the upper 
side of the guide shoe 8 for the engagement of a plate-shaped coupling 
piece 15 which is provided, at its upper end, with a transverse-force 
piece 16 which is arranged slightly offset and whose function will be 
described below. The insertion pocket 14 is bounded on its two 
longitudinal sides by mutually parallel side walls 17 and 18 of the guide 
shoe. It can seen, in particular in FIG. 2 that the inner surfaces of the 
two parallel side walls 17 and 18 of the guide shoe 8 are designed as 
vertically disposed flat surfaces which form contact surfaces for the 
plate-shaped coupling piece 15 whose side surfaces which face the inner 
surfaces of the side walls 17 and 18 are likewise designed as flat 
vertical surfaces. In this case, the width of the coupling piece 15 
corresponds essentially to the inside width of the insertion pocket 
between the inner surfaces of the side walls 17 and 18, so that the 
coupling piece 15 is held in the insertion pocket 14 virtually without 
play apart from pivotability about an approximately horizontal axis. 
As shown in FIGS. 3 to 5, the guide shoe 8 is of symmetrical design 
relative to its vertical centre plane. Arranged on the outside of the 
inner side wall 18 is a fixed guide projection 19 which, as shown in FIGS. 
4 and 5, extends over the entire length of the guide shoe 8 and is 
designed as a hook strip which is provided with an upright guide hook 20. 
As shown in FIG. 1, the hook strip 21 engages from below around the guide 
strip 9 which is fixedly arranged on the conveyor, the guide hook 20 
engaging behind the guide strip 9 in a slot cutout, so that the cutting 
machine 1 is guided in the horizontal and vertical direction on the guide 
strip 9 by the guide shoes 8. 
The parallel side walls 17 and 18 of the guide shoe 8 each have bolt holes 
22 which are flush in the centre thereof and into which a horizontal 
transverse bolt 23 is inserted, whose bolt axis 24 runs transversely to 
the longitudinal direction of the conveyor 2 and accordingly transversely 
to the direction of travel of the cutting machine 1. The transverse bolt 
23 inserted into the flush bolt holes 22 passes through a bolt hole 25 of 
the coupling piece 15 in the insertion pocket 14, as a result of which the 
guide shoe 8 is held on the coupling piece 15 so that it can be pivoted up 
to a limited extent about the transverse bolt 23. 
As can best be seen in FIG. 2, the coupling piece 15 is integrally 
connected, at its upper end which protrudes out of the insertion pocket 
14, to an approximately plate-shaped transverse-force piece 16 which is of 
approximately trapezoidal design in its plan view and has two narrow 
convexly curved end faces 26 extending transversely to the direction of 
travel of the cutting machine 1 and two longitudinal sides 27 which 
converge slightly towards the end faces 26. Arranged centrally on the 
upper side 28 of the transverse-force piece 16 is a vertical journal 29 
which engages from below in a bearing hole 30 provided on the guide arm 7 
and thus allows the entire guide shoe to pivot about an approximately 
vertical axis 31. In this case, the arrangement is such that, with the 
vertical journal 29 engaging in the bearing hole, the transverse-force 
piece 16 lies in a cutout 32 in the guide arm 7, the convexly curved end 
faces 26 resting against the front and rear narrow sides 33 of the cutout 
32, as can be seen in particular in FIG. 4. As a result, the transverse 
forces transmitted from the guide shoe to the guide arm and vice versa in 
the direction of travel of the cutting machine 1 are transmitted via the 
transverse-force piece 16 and not by the pivoting journal 29 which is thus 
decoupled from these forces and will not be damaged even under high 
impact-type loading on the connection of the guide arm and guide shoe, for 
example by a boulder jammed in the guide rail. 
In order to prevent the guide shoe 8 dropping down out of the guide arm 7, 
the transverse-force piece 16 projects at its end-face end regions 34 
beyond the coupling piece 15 with edge beads 35 which are approximately 
square in section and is held on the guide arm by holding webs 36 which 
engage below the edge beads 35. Since the cutout 32 on the guide arm is 
designed to be laterally open, as emerges in particular from FIG. 4, the 
guide shoe can easily be mounted on the guide arm in that, having been 
rotated through about 90.degree. in relation to its longitudinal 
direction, it is inserted with its vertical journal 29 into the bearing 
hole from below and is then rotated through about 90.degree. into its 
operating position, the holding webs 36 engaging below the edge beads 35 
and holding the guide shoe in a positive-locking manner. 
It can be seen that, by means of the invention, adaptation of the guide 
shoe to the course of the guide rail 9 is not only possible in the 
vertical direction, that is to say in the case of an uneven floor 3, but 
the arrangement, which can also be pivoted about a vertical line, can also 
easily compensate for a curved course of the guide rail which occurs, for 
example, when advancing the individual conveying elements (conveyor pans). 
The invention is not limited to the embodiment described and illustrated, 
but a large number of changes and modifications are conceivable without 
departing from the scope of the invention. For instance, the narrow sides 
33 of the cutout 32 could thus likewise be of curved design, i.e. drawn in 
concavely with a radius of curvature which corresponds to the radius of 
curvature r of the end faces 26, so that the force-transmitting surface 
between these two components is enlarged and permissible surface pressures 
are not exceeded.