Note: Descriptions are shown in the official language in which they were submitted.
21 71 7~9
A Method for Cutting Belts that Incorporate
Reinforcing Inserts, and a Cutter for Belts
of such a Kind
The present invention relates to a method for cutting belts that
incorporate reinforcing inserts, in particular for cutting
conveyor belts that are of an armoured elastomer, in which the
belt is arranged between two clamping jaws; in order to make the
cut, the clamping jaws, with the belt arranged between them, are
pressed against each other and at the same time a cutter is
guided along the clamping jaws, transversely to the longitudinal
direction of the belt, and through the belt material, this being
done by means of a drive system.
The present invention also relates to a cutter for belts that
incorporate reinforcing inserts, in particular for conveyor belts
that are of an armored elastomer, with a clamping system
consisting of two clamping jaws that are transverse to the belt
and can be clamped against each other with the belt interposed
between them, and with a cutter having at least one cutting edge,
which can be moved along the clamping system by means of a drive
system.
A method and a cutter system of the type described in the
introduction hereto are described in French Utility Model
Certificate 2458497. An elastic belt, which can be a fabric with
rubber-coated threads, is separated into individual strips by a
plurality of transverse cuts; these strips are subsequently used
to manufacture the carcass of a tire. The belt that is used as
raw material is clamped between two clamping jaws that can be
pressed against each other and a cutter that can move
horizontally is guided through the material of the belt. When
this is done, the material from which the belt is made lies on a
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conveyor belt that is of rubber. In order to avoid the conveyor
belt being cut to pieces by the cutter, on the lower edge of the
cutter, which is fitted with two sickle-shaped blades, there is
rounded, wider section, like a bead. During the cutting process,
the bead presses the elastic conveyor belt downward, part way
into a wide groove in the lower clamping jaw, so that no damage
is done to said conveyor belt during the cutting process. The
cutter is secured to a carriage that can be moved precisely along
the upper clamping jaw. The depth of the cut made by the cutter
is so adjusted that the edge of the belt that is to be cut slides
along the upper side of the belt, and thus in the transition area
between the bead and the sickle-shaped cutter blade, during the
cutting process.
The known cutter system can be used to cut up fabric, and in
particular rubber coated fabrics. In contrast to this, it has
been shown to be unsuitable for cutting up heavy-duty conveyor
belts, in particular conveyor belts that are armored with steel
wires, of the kind used, for example, for moving coal and rock in
open-cast and underground mining operations.
Today, conveyor belts that are reinforced by steel cables or wire
mesh are mostly cut up by hand, since no machines or machine
processes suitable for this purpose are available. As a rule, in
order to do this, the elastomer that encloses the armouring is
first cut open from both sides in the form of a wedge that is as
deep as possible. Next, a commercially available, hand-held
cutting wheel is used to cut through each individual steel wire.
This work, which requires at least three persons to perform, is
extremely laborious, very noisy, and generates large quantities
of dust. When this work is being done with a cutter wheel, it is
impossible to avoid the rubber material being cut by the cutting
wheel, which means that this work is also associated with the
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generation of vapors and an unpleasant odor. A cut that is made
in this way through a steel-armored conveyor belt that is two
meters wide takes between half an hour and one hour to complete.
This amount of time is acceptable if all that is required is a
single cut through the belt, in order to make repairs, for
example. However, it is quite unacceptable if a conveyor belt
that is completely unserviceable is to be cut into short
sections, ready for disposal, as will be the case in the future
in view of increasingly strict environmental legislation.
It is the task of the present invention to create a cutting
method by which all kinds of belts that incorporate reinforcing
inserts, and in particular belts that incorporate steel
armouring, can be cut up quickly, and which ensures a long
service life for the cutting tools that are used. In addition, it
is intended to create a cutting system that is suitable for this
purpose.
In order to solve this problem, with respect to the method, it is
proposed that during the cutting process the material from which
the belt is made be cut on both sides by cutting edges of the
cutter, said cutting edges subtending an acute angle and being
straight or curved convexly to the belt. It is preferred that the
cutter be guided through the material of the belt with
considerable vertical free play when the cutter will center
itself automatically relative to the reinforcing inserts embedded
in the belt.
Also proposed for the solution of this problem is a cutter system
of the type described in the introduction hereto, in which the
cutting edge is straight or curved convexly towards the belt, an
additional cutting edge being arranged at an acute angle to the
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first cutting edge, and that the belt be located between these
two cutting edges during the cutting process.
Because of the essentially V-shaped arrangement of the two
cutting edges, which work in conjunction with each other, it is
possible to cut through belts, even those that incorporate steel
armouring, unusually quickly and in a manner that ensures that
the cutter blades have a long service life. A rubber belt that
incorporates steel-cable armouring and that is two meters wide
can be cut through in less than two minutes, and this is done
without the creation of a great deal of dust and with very little
noise. Only one supervising operator is required when this
process is carried out.
In a preferred embodiment of the present invention, the two
cutting edges of the cutter system are located on the cutter.
These two cutting edges can be arranged symmetrically to each
other when together they form the approximately V-shaped cutting
notch; such a configuration of the cut leads to the fact that the
cutter centers itself automatically relative to the reinforcing
inserts that are incorporated in the belt. The maximum cutting
force is concentrated precisely where the greatest resistance of
the material is to be overcome, which is to say in the area of
the armouring through which the cut is to be made.
In order to allow the cutter to center itself relative to the
armouring, the cutter can have considerable clearance in the
direction that is perpendicular to the flat side of the belt; in
contrast to this, the cutter should be held so as to be
essentially rigid in the longitudinal direction of the belt.
The present invention also proposes that the cutter be arranged
on a carriage that can move back and forth along the clamping
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system. In order to permit the cutter to have the desired free
play, cutter can be secured rigidly to the carriage, in which
case the carriage is guided with considerable clearance on one of
the two clamping jaws of the clamping system.
It has also been shown to be advantageous if the tractive forces
that move the carriage act as closely as possible to the cutters.
To this end, one embodiment of the present invention proposes
that the carriage be provided with supporting rollers on its long
side that is remote from the cutter; these rollers can run on
guide surfaces of the clamping jaw that accommodates the
carriage; it is also proposed that means of traction be provided
to move the carriage, these being secured on the carriage, level
with that half of the carriage that is proximate to the cutter.
In order to prevent the cutter from migrating to one side or the
other, the clamping jaw can be provided with an elongated slot
through which the cutter is guided. In this case, lateral
guidance of the cutter can be effected either wholly or in part
by the elongated slot.
For practical use of the cutter system in conveyor systems, it
has been shown to be advantageous if the clamping jaws can be
pivoted toward each other by means of a hinge joint, and the
cutter system, including the clamping jaws, be completely opened
at the end that is remote from the hinge joint, so that the belt
can be slid between the open clamping jaws from the side. In this
way, it is possible to make cuts in situ without disassembling
the whole cutting system, e.g., to make such cuts on conveyor
belts within a belt assembly when they require repair. In order
to make it simpler to move the cutter system, it can be fitted
with lifting eyebolts on its upper side, so that the cutter
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system as a whole can be lifted by a gantry-type crane or other
apparatus and moved to the desired place, or can be pivoted into
a belt assembly.
Additional features and advantages of the present invention will
be described in greater detail below, on the basis of the
drawings appended hereto. These drawings show the following:
igure 1: a diagramatic front view of a cutters system to cut
through an elastomer that is armored with steel cables;
Figure 2: a plan view of the system shown in Figure 1:
Figure 3: a perspective view of the system shown in Figure 1 and
Figure 2, with one section shown cut away for greater
clarity;
igure 4: a detail of a cross section on the line IV-IV in Figure
l;
igure 5: a detail from Figure 3 at even larger scale;
igure 6: a cross section on the line VI-VI in Figure 4, showing
a carriage with an attached cutter;
igure 7: a view as in Figure 5 showing a second embodiment of
the cutter system;
igure 8: a view as in Figure 6 showing a second embodiment of
the cutter system;
igure 9: a view as in Figure 3 showing any third embodiment of
the cutter system;
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Figure 10: a detail of the cutter system shown in Figure 9;
igure 11: a cross section at greater in the area of the
cutter, through a cutter system;
igure 12: a cross-section on the line XII-XII in Figure 11.
Figures 1 to 4 show that the apparatus that is used to carry out
the cutting process comprises a fixed sub-structure 1, at the
outer ends of which there are two supports 2. Two horizontal
U-sections 8 are arranged opposite each other and, as can be seen
from Figure 4, these form an upper inner clamping jaw 10 that
incorporates a hollow spacei these two sections of the clamping
jaw 10 are connected rigidly to each other by means of the
U-clamp piece 9. A movable frame 1' is so arranged that it can
slide vertically on the sub-structure 1. The movable frame
contains a pair of horizontal U-sections 3 that are arranged
opposite each other and in this way form a lower channel-like
clamping jaw 13. Two pairs of vertical side beams are arranged
close to the ends of this lower clamping jaw 13, and these are
connected at their ends by means of a cross tie 5. In addition,
there are two horizontal longitudinal beams 6 between which are
installed a plurality of parallel rollers 7 so as to form a
horizontal supporting surface for the belt that is to be cut up.
At their opposite ends, the two vertical side beams are connected
in pairs by means of cross pieces 4'. Each cross piece 4' is
supported by a double-acting cylinder 12, the shaft of which is
connected to the U-clamp 9 that is installed on the upper
clamping jaw 10 and is located between the side beams 4. The
cylinders 12 are either hydraulic or pneumatic cylinders. They
can work synchronously in order to raise or lower the lower
movable clamping jaw 13 in such a way that this remains parallel
to the fixed upper clamping jaw 10. There are off-set guide
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elements arranged between the fixed section 8 and the
vertically movable side beams 4. These elements can incorporate
guides, although these are not shown in the drawing.
The upper flanges 14 of the sections 3 form the clamping surfaces
of the lower clamping jaw 13 and are located at about the same
level as the surface of the rollers 7. As can be seen in Figure
5, the flanges 14 are separated by a slot 16 through which a
cutter 17 can move. The lower flanges 18 of the section 8 form
the clamping surface of the upper clamping jaw 10 and are
similarly separated by a slot 19 that permits passage of the
cutter 17.
In the drawing, the flanges 14 and 18 that are opposite each
other, together with the clamping surfaces that are formed by
them, are shown as being flat. However, they can also incorporate
raised portions or additional shapes in the form of ridges,
pyramids, and the like in order to hold the belt that is to be
cut up more securely, particularly if this belt is of an
extremely elastic material and displays a recognizable wear
pattern.
The two sections 8 that form the upper, fixed clamping jaw 10
contain the cutting means that consist of a carriage with the
cutter 17, as well as a chain-drive system 21 that runs over two
sprockets 22, 23 that are mounted on the ends of the sections 8.
The sprocket 22 is driven by an electric geared motor 24. The
other sprocket 23 is installed on a chain-tensioning system that
has an opening 26 in the vicinity of each section 8; these
openings simplify installation and removal of the cutter 17 on or
from the carriage 20. A removable housing 27 that is arranged
above the lower clamping jaw 13 protects the blade in this area.
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Another housing 28 protects the drive system for the chain that
is used to move the carriage 20.
Figures 5 and 6 show the carriage 20 that consists essentially of
two side plates 20, between which the cutter 17 is located. The
ends of the chain are secured at the ends of the two plates 30.
The carriage is guided in the interior of the section 8 by means
of ball bearings 33 that serve as rollers. The outside diameter
of each ball bearing is smaller than the clearance within the
interior of the section 8 in order to allow free play 34 for the
carriage 20 and the cutter 17, and permit the cutter 17 to center
itself on the belt that is to be cut up, as will be described
below. The plates 30 and the cutter 17 are connected to each
other by horizontal bolts that pass through bores.
Figure 6 shows that each end of the cutter 17 incorporates a
cutting notch that is approximately V-shaped in longitudinal
profile and comprises two parts 36 and 37 that are directly
opposite each other, with each being symmetrical to the other
relative to the horizontal center line 30. Each V-shaped cutting
notch ends in a center concave section 39. The cutter 17 is
preferably of high-speed steel that is cut out by means of a
laser. The treatment of the cutting notch and the cutting angle
will depend on the product that is to be cut up. In general, it
is not made extremely sharp, so that the cutter notch remains
less sensitive. Such a design makes it possible to manufacture a
relatively thin cutter 17 that can cut rubber and even metal
armouring and other material that may be embedded in the rubber.
The symmetrical arrangement of the two parts 36 and 37 of the
cutter makes it possible for the cutter 17 to be self-centering
relative to the element that is to be cut up and which is held
between the two clamping jaws 10, 13. In the present case, it is
21 71 79 9
the vertical free play of the carriage within the upper clamping
jaw 10 that permits this self-centering.
This free play can also be obtained if the cutter 17 is installed
so as to be able to move on the carriage 20. During the cutting
process, the cutter 17 is moved transversely to the belt and
through the slots 16 and 19 that are located between the two
upper and lower clamping jaws 10, 13.
The fact that the cutter 17 has two pairs of cutter parts 36, 37
makes it possible to make alternating cuts, first in one and then
in the other direction. But even in those cases in which an
alternating cut is not intended, this type of cutter can be of
interest because once one cutter notch has become blunt, the
working direction can be reversed and a change-over be made so
that the other cutting notch is used.
As compared to Figures 1 to 6, Figures 7 and 8 show a variation
of the cutter by that makes it possible to cut particularly thick
belts that are reinforced by very thick steel cables. The cutter
50 is the essential element of a carriage 51, and the upper
clamping jaw 10 contains an axle 52 with two journal bearings 53
that have ball bearings. Within the lower clamping jaw 13 there
is an axle 54 with two journal bearings 55 that have ball
bearings. The cutter 50 has a straight cutting edge 50' that
extends obliquely in the direction in which the cut is made. It
is preferred that this be manufactured from high-speed steel. The
flange 14 of the lower clamping jaw 13 can be provided with fixed
blades 56 that are similarly manufactured from high-speed steel.
The blade 56 consists of two cutting edges 56' on both sides of
the slot 16 of the lower clamping jaw 13. As soon as the cutter
50 encounters resistance during the cutting process, it is held
in a position in which the journal bearings 53 of the carriage 51
21 71 ~99
press against the upper flange of the section 8, when the slide
bearings 55 are pressed against the back of the flange 14 of
section 3. In this position, the cutter notch 50' exerts a force
on the belt that is to be cut and part of this is directed onto
the lower clamping jaw 13 and attempts to squeeze the inner cable
of the belt that is to be cut between the cutting edge 50' of the
cutter 50 and the cutting edges 56' of the blades 56. In one
variation it is also possible that the cutter 50 incorporate a
notch of such a kind that a cutter notch that is V-shaped as in
the previously described embodiment will result.
The method is very simple to carry out, and it can be automated
without any difficulty. The appropriate operating systems are
installed in the control box 40 which, amongst other items,
contains the electrical control unit and the power supply for the
geared motor, as well as the electro-hydraulic or
electro-pneumatic units for actuating the cylinder 12.
Figure 3 shows the belt 41 that is to be cuti this is a rubber
conveyor belt that is reinforced, for example, by wires or metal
cables 42 that must be cut transversely, along a cut line 43. The
belt 41 that is placed upon the rollers 7 can be pushed between
the clamping jaws 10 and 13 manually by an operator before the
cutting process begins. In this way, it is possible to cut up an
old, worn out conveyor belt into small pieces that are easy to
handle, and to do so very quickly.
Once the belt 41 has been correctly positioned between the
clamping jaws 10, 13, with the desired cut line in the proper
position, these clamping jaws 10, 13 are pressed against each
other by actuating the cylinder 12. Then, the blade 17 that is
initially located at one end of the clamping jaws 10, 13 starts
to move, driven by the drive system. Because of the fact that the
11
2~7~799
two cutting edges of the cutter are arranged at an acute angle
relative to each other, during the cutting process the belt 41 is
located between these two cutting edges, i.e., the blade 17
centers itself automatically relative to the belt 41. The belt
material is cut from both sides by the cutting edges so that a
symmetrical and particularly powerful cutting action results, and
this cuts through the metal armouring without any problem.
Figures 9 to 12 show another embodiment of the cutter system. The
ends of the clamping jaws 10, 13 are connected at one end through
a hinge joint 60. In order to make it possible to push the belt
41 between the opened clamping jaws 10, 13 from the other side,
the cutter system, including the clamping jaws 10, 13, can be
opened completely at the end 61 that is remote from the hinge
joint 60. To this end, as can be seen in Figure 10, the piston
rod 62 of the cylinder 12 can be released from the lower clamping
jaw 13 after removal of a safety pin 63 from the lower clamping
jaw 13. Then the lower clamping jaw 13 can be dropped away from
the upper clamping jaw 10 by pivoting it about the hinge joint
60, and the belt 41 can be inserted or removed at the side. This
is a particular advantage in the case of repairs to endless
conveyor belts that cannot be inserted into the cutter system
from the end. A stop 64 that can be swung into position between
the two clamping jaws 10, 13 is located at the same end of the
clamping system as the hinge type 60, and this limits the maximum
angle to which the clamping jaws 10, 13 can be opened.
Lifting eyebolts 65 in the top of the cutter system make it
possible to lift this to the desired workplace by means of a
crane, and optionally make cuts when it is in the raised
position. Guides for the forks of a fork-lift truck or other
load-handling equipment can be used for this purpose in place of
the lifting eyebolts 65.
12
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In the embodiment of the clamping jaws 10, 13, of the carriage
20, and of the cutter 17 that is shown in Figure 11 and Figure
12, each of the two clamping jaws 10, 13 consists of two parallel
beams in the form of a double-T. The upper pair of beams form the
upper clamping jaw 10, the lower pair of beams form the lower
clamping jaw 13; the space between the beams is so narrow because
of suitable distance pieces that the elongated slots 16, 19 that
are just wide enough for passage of the cutter 17. In this way,
the cutter 17 is guided mainly by the edges of these elongated
slots 16, 19. The guide slot that is formed in this way is so
narrow that the cutter 17 is held so as to be essentially rigid
in the longitudinal direction of the belt.
In contrast to the foregoing, the cutter 17 has an obvious amount
of free play 34 in the direction perpendicular to the flat sides
66 of the belt 41. This free play 34 is made up of an upper space
34' and a lower space 34", as is shown in Figure 12. The upper
space 34' is located between support rollers 67 in the area of
the upper longitudinal side of the carriage 20 and the guide
surfaces 68 of the clamping jaw 10 that accommodates the
carriage. The lower space 34" is located between the under side
69 of the carriage 20 and the flange 18 of the clamping jaw 10
that is located there. The drive system 21 in the form of the
chain is secured by a pin 69' close to the under side of the
carriage 20 in order that the force be applied close to the
carriage 17.
Because of this free play for the carriage 20, the cutter 17 that
is connected rigidly to the carriage 20 centers itself
automatically in the vertical direction with reference to the
belt 41 or the wires and metal cables 42 that are embedded
therein. During the cutting process, these wires move precisely
into the concave ground section 39, where the two symmetrically
13
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ground cutting edges 70, 71 of the cutter converge. The space
between the cutting edges 70, 71 is smaller here than the
diameter of the metal wires 42 that are to be cut through. In the
embodiment shown in Figure 12, the cutting edges 70, 71 that are
in a V-shaped configuration and subtend an acute angle are
straight. However, it is also possible to give the cutting edges
70, 71 a slightly convex shape in the direction of the belt 41,
e.g., to impart a parabolic shape to them. In this case, the
cutting edges 70, 71 form an ever more acute angle in the
direction toward the end of the cutting notch, in the section 39.
The average angle between the cutting edges 70, 71 should be at
least 10 degrees and at most 45 degrees in this case.
In place of grinding the cutter 17 itself, it is also possible to
configure the cutter as a cutter body in which suitable cutter
inserts are then installed, e.g., cutter inserts that are of
tungsten, (Widia steel) or ceramic. In this case, it is not
necessary to disassemble the cutter or the carriage when the
cutter becomes blunt. All that need be done is to replace the
cutter inserts.
In order to ensure that equal pressure is exerted by the clamping
]aws 10, 13 across their whole length it is possible to provide
suitable line of flexure compensation, e.g., by a precisely
determine convex pre-curvature of the two clamping jaws 10, 13
toward each other.
14
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INDEX TO REFERENCE NUMBERS
REFERENCE
1 SUBSTRUCTURE
1' FRAME
2 SUPPORT
3 SECTION
4 SIDE BEAM
4' CROSS PIECE
CROSS TIE
6 LONGITUDINAL BEAM
7 ROLLER
8 U-SECTION
9 U-CLAMP
UPPER CLAMPING JAW
12 CYLINDER
13 LOWER CLAMPING JAW
14 FLANGE
16 SLOT
17 CUTTER
18 FLANGE
19 SLOT
CARRIAGE
21 DRIVE SYSTEM
22 SPROCKET
23 SPROCKET
24 GEARED MOTOR
CHAIN TENSIONING SYSTEM
26 OPENING
27 HOUSING
28 HOUSING
SIDE PLATE
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33 BALL BEARING, SUPPORT ROLLER
34 CLEARANCE
34" CLEARANCE
34' CLEARANCE
36 FIRST PART OF CUTTER
37 SECOND PART OF CUTTER
38 CENTRELINE
39 CONCAVE SECTION
CONTROL BOX
41 BELT
42 WIRES, METAL CABLES
43 CUT LINE
CUTTER
50' CUTTING EDGE
51 CARRIAGE
52 AXLE
53 SLIDING BEARING
54 AXLE
SLIDING BEARING
56 FIXED BLADE
56' CUTTING EDGE
HINGE JOINT
61 END
16
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62 PISTON ROD
63 SAFETY PIN
64 STOP
LIFTING EYEBOLT
66 FLAT SURFACE OF BELT
67 SUPPORTING ROLLER
68 GUIDE SURFACE
69 UNDERSIDE OF CARRIAGE
69' PIN
FIRST CUTTING EDGE
71 SECOND CUTTING EDGE
17
