EP0358112A1 - Cutter jib for cutting machines for cutting rock, concrete, etc. - Google Patents

Abstract

On a cutter jib for cutting machines for cutting rock, concrete, etc., an endless flexible cutting belt equipped on the outside with cutting tools and on the inside with supporting members is arranged in an open guide channel, which cutting belt, driven by a drive pinion, revolves. To reduce the friction between the supporting members and the guide surfaces in the guide channel, provision is made for the supporting members to rest on an endless flexible inner belt which revolves on rolling bodies on the base of the guide channel. A very substantial saving in drive energy as well as a clear reduction in wear on the guide surfaces of the guide channel and on the cutting belt are achieved by the reduction in the friction. <IMAGE>

Description

The invention relates to a cutting arm for cutting machines for cutting stone, concrete, etc., on which in an open guide channel an outer rotating cutting belt driven with cutting tools and inside with supporting members rotates, the supporting members being mounted on the bottom and on the side walls of the guide channel and being longitudinally movable are guided and the lower part of each support member is designed for engagement with a corresponding toothing of a drive pinion at one end of the cutting arm.

In known cutter arms of the above type, as can be seen, for example, from BE-PS 865 185/78, the support members slide on the bottom and on the side walls of the guide channel along the straight or slightly curved channel sections between the drive pinion at one end of the cutter arm and a deflection wheel at its other end. Despite the introduction of water, a high level of sliding friction occurs, in particular at the bottom of the guide channel, with the result of rapid wear of the support members and also of the channel wall, especially since cutting dust penetrating into the channel has an emery effect. At the same time, the guide channel and the cutting belt and in particular the support members are heated up strongly.

Attempts have already been made to reduce the sliding friction by installing a large number of water nozzles on the bottom of the guide channel (EU-PS 0 014 776). The water should form a pillow, or at least a film on the floor of the guide channel, on which the guide members should float. However, it has been found that extremely high water pressure combined with a large amount of water is required to actually create and maintain a continuous water lubrication film that achieves the desired separation between the underside of the support members and the bottom of the guide channel. The high water pressure means that the cutting machines are equipped with high-pressure pumps in conjunction with a correspondingly high energy consumption, which makes cutting stone with such cutting machines uneconomical.

The invention is therefore based on the object of further developing a cutting arm of the type mentioned in such a way that the friction is significantly reduced and thus the energy consumption and the wear on the channel guides and on the cutting belt are reduced.

This object is achieved in that the support members rest on a flexible inner belt which rotates on rolling elements on the bottom of the guide channel. The invention thus takes a path that deviates from the conventional guidance and mounting of the cutting belt in the guide channel of the cutting arm. This new mounting can also be transferred to cutting chains that slide in a guide channel, even if the invention is explained and supplemented below with reference to a flexible cutting belt. A corresponding transfer of the individual parts of the invention to conventional cutting chains, namely the placement of a cutting chain on a flexible inner belt in the guide channel, which rotates on rolling elements arranged on the bottom of the guide channel, is readily possible for the person skilled in the art.

By supporting the support members on an endless flexible inner belt, which in turn rests on rolling bodies that roll in the running direction or at least rotate in the running direction and are located on the bottom of the guide channel, the major part of the sliding friction that has previously occurred with conventional guides and bearings is eliminated. If there is still friction in the guide channel on the support members, this is limited to a side friction that is practically negligible in the friction calculation due to the lateral guidance of the support members on the side walls of the guide channel. Instead, rolling friction occurs when the rolling elements roll on the underside of the inner belt and on the bottom of the guide channel. But the rolling friction is extremely low compared to the sliding friction, so that a considerable energy saving in connection with a significant reduction in wear on the guide channel and on the cutting belt and in particular on the support members etc. is achieved. The amount of spare parts and maintenance work is reduced accordingly.

The essence of the invention can be summarized in that the flexible cutting belt is placed on rolling elements which operate in the guide channel in the same direction of movement as the cutting belt, with the interposition of an inner belt between the rolling elements and the cutting belt, through which the rolling elements are held in the guide channel and which transfers the cutting pressure acting on the support members evenly to the rolling elements.

Although embodiments of the invention allow the roller bearing in the guide channel to be limited to the long sections between the drive pinion and the reversing bend at the other end of the arm, the invention provides for the guide channel to form a closed loop, the pinion-side reversing bend of which runs in front of the drive pinion. While the cutting belt runs over the drive pinion as before, with its support members engaging with corresponding toothed members of the drive pinion, the closed loop of the guide channel bends before reaching the drive pinion, so that the cutting belt separates from the inner belt and only after it has rotated the drive pinion comes into engagement with the inner belt again. At this point, it should be pointed out that the inner belt is frictionally entrained by the support members at substantially the same speed.

According to the invention, the inner belt and the rolling elements are guided on the side walls of the guide channel, so that both the inner belt and the rolling elements are given an exact path of movement and high circulation speeds are readily possible due to this reliable guidance.

The rolling elements preferably consist of rollers which are arranged in a row one behind the other in the guide channel. The rollers transmit the cutting pressure taken over by the inner belt through line contact to the entire width of the bottom of the guide channel. Like the associated guides in the guide channel, they are very easy to manufacture and assemble. Replacement work is also easy to carry out.

According to a first alternative of the invention, the rollers are rotatably mounted in the guide channel in the manner of a roller table. In this case, the rollers are rotatably mounted either directly on the side walls of the guide channel or in a corresponding insert or cage which is inserted in the guide channel. In this embodiment, the roller bearing on the reversing sheet near the sprocket can be made simpler or lighter if necessary, if only the inner belt is to be deflected, but not also a roller conveyor as in other versions.

An important development of the invention is that the sides of the rollers are slightly conical or spherical in shape so that the side friction is as low as possible, and yet a sufficiently wide roller circumference is retained.

According to a second alternative of the invention, which is preferred, the rollers are inserted loosely into the guide channel, wherein they are held together by the inner belt in the guide channel. They form a dense row of rollers, each of which rolls on the top of the inner belt and below on the bottom of the guide channel. As a result of this rolling process, the inner belt rotates twice as fast as the rolling element train, or, conversely, the rolling elements rotate at half the speed relative to the inner belt and the cutting belt, so that the friction is reduced accordingly.

The rollers are dimensioned such that they are guided with a slight play between the two opposite side walls of the channel, preferably with a small contact surface due to the slightly conical or spherical shape of the sides of the rollers. However, it is also possible to give the roles an additional guide if this proves to be expedient. In this case, according to the invention, the loosely inserted rollers are provided on both sides with pins which engage in guide grooves parallel to the floor on the side walls of the guide channel. This guide can facilitate maintenance work, for example, if the inner belt is removed and the loosely inserted rollers are then no longer held together by the inner belt. A holding strap with the inner belt can also be put on the rollers for holding the same together when the inner belt is removed. However, guidance by means of pins and grooves can be preferred.

In the case of guiding the rollers by means of pins and guide grooves, the dimensions and spacings of the pins and the guide grooves should be chosen according to the invention such that the pins do not touch the wall of the guide groove when the rollers are in contact with the ground. This arrangement creates no additional friction during normal operation of the cutter arm, and the pins and guide grooves only take on a function in exceptional cases, namely when the inner belt is removed, for example.

In order to reduce the already relatively low rolling friction, the rollers can each have an annular recess in the middle, so that they - seen in profile - assume a dumbbell shape, have a lower weight and, in addition, only have the guide surfaces on the right and Left full disks in the recess are in contact.

Instead of a loose arrangement of the rollers in the guide channel, it can alternatively be provided according to the invention that the rollers are connected to one another in the manner of a roller chain. In this case, too, the rollers remain in the guide channel when the inner belt is removed. In addition, this solution allows the rollers to be kept at a predetermined distance from one another. Guiding by means of pins and guide grooves can be omitted in this embodiment. A connection from roll to roll can, for example, very easily consist of a curve-flexible, longitudinally rigid strand with annular eyes arranged at the roll spacing for receiving lateral pins of the rolls. This connecting strand only has the task of holding the rollers at a predetermined distance in the guide channel, so that they are not subjected to tensile force comparable to a roller chain.

As an alternative to arranging rollers in the guide channel, the roller bodies can also consist of balls. The balls are preferably arranged on the inside in two rows in the guide channel, which are separated from one another. The balls are expediently inserted loosely and separated from one another by a partition. The balls, like the rollers, in particular if they are arranged next to one another in two rows, ensure reliable support of the inner belt, which in turn forms a moving pressure and support surface of the support members of the cutting belt. The rows of balls are also guided on both sides in the guide channel, so that their path of movement is predetermined. Due to the almost punctiform engagement of the balls with the adjacent contact surfaces of the guide channel and the inner belt, the friction is reduced even further, the wear on the guides, the inner belt and the others moving components is also less than when using rollers.

Instead of loosely inserted balls, it is possible according to the invention to let the balls run in rows in cages in order to ensure a mutual connection and assignment under all operating circumstances. The cages can be designed similarly to ball bearings.

No matter how the roller body and its guidance and arrangement is designed, according to the invention, preferably for cooling, in particular the roller body and the inner belt and the guide channel, water should be able to be introduced by means of feeds into the lower section of the guide channel. Lubrication and, above all, rinsing and keeping the rolling elements and their guide surfaces clean should be achieved at the same time. The feeds should preferably be arranged in the bottom of the guide channel in order to achieve the most uniform possible distribution and effect.

The rolling elements should be made of plastic, in particular for reasons of weight. The plastic should be pressure-resistant, abrasion-resistant and corrosion-resistant, especially waterproof. Plastic roller bodies run quietly and cause little wear on the guides. It can also be provided that the rolling elements are given a wear-resistant metal jacket.

In order to reduce the friction even further and to ensure self-cleaning of the guide channel by water rinsing, according to the invention the floor and the side walls of the guide channel should have a smooth, in particular polished and highly wear-resistant surface, which can possibly be achieved with a coating or a lining of the guide channel.

The support members should mainly consist of a pressure-resistant and highly wear-resistant plastic for weight reasons, with which the function of the support members, including their function as a drive means for the cutting belt, is guaranteed. The support members can also have a metal casing for reinforcement. It can be advantageous if the cross-sectional support members have the shape of an isosceles trapezoid with drawn-in end faces, so that despite a sufficient height of the support members and a short distance from one another, a relatively small deflection bend and thus a correspondingly small drive pinion is made possible.

In order to optimally support the support members through the new guidance and storage by means of inner belts and rolling elements, it should be noted according to the invention that the diameter and thus the mutual distance of the rolling elements are matched to the length of the supporting elements and their spacing from one another such that the supporting elements cannot tilt under the cutting pressure. This presupposes that the section of the inner belt receiving a support member always rests on at least two rolling bodies or pairs of rolling bodies running one behind the other.

The inner belt - like the cutting belt - should have belt inserts where possible, so that no undesired elastic or even permanent elongation of the inner belt can occur.

• Fig. 1 eine Seitenansicht eines erfindungsgemäß ge­stalteten Schrämarms;
• Fig. 2 eine Teilansicht eines Längsschnitts eines ersten Ausführungsbeispiels eines erfindungs­gemäß gestalteten Schrämarms;
• Fig. 3 eine Querschnittsansicht zu Fig. 2;
• Fig. 4 eine Teilansicht eines Längsschnitt eines zweiten Ausführungsbeispiels eines erfindungs­gemäß gestalteten Schrämarms;
• Fig. 5 eine Querschnittsansicht zu Fig. 4.

Embodiments of the invention are explained below with reference to the drawing. The drawing shows:

• 1 shows a side view of a cutting arm designed according to the invention;
• 2 shows a partial view of a longitudinal section of a first exemplary embodiment of a cutting arm designed according to the invention;
• FIG. 3 shows a cross-sectional view of FIG. 2;
• 4 shows a partial view of a longitudinal section of a second exemplary embodiment of a cutting arm designed according to the invention;
• 5 shows a cross-sectional view of FIG. 4.

The cutting arm shown in FIG. 1 has an external, endless and flexible cutting belt 1, which is equipped with cutting tools 2 on the outside and support members 3 on the inside. The cutting belt 1 is driven by a drive pinion 4, with the teeth 5 of which the support members 3 engage in the manner of a toothing.

The cutting belt 1 is held and guided on its circulation by an outwardly open guide channel 6 on the cutter arm, which is formed on the outer edge of a base body 7 by a web 8 of the same and on both sides of the web 8 by means of screws 9 fastened side plates 10.

The guide channel 6 forms a closed loop, the pinion-side reversing arc 11, as can be seen from Fig. 1, runs in front of the drive pinion 4, so that the cutting belt 1 leaves the guide channel 6 at the beginning of the reversing arc 11 for the circulation around the drive pinion 4 and then enters the guide channel 6 again.

In the guide channel 6, the support members 3 of the cutting belt 1 rest on an inner belt 12, which in turn is mounted on rolling elements 13 and is therefore carried along by the cutting belt 1 and also rotates on the cutting arm.

As can be seen from the first exemplary embodiment according to FIGS. 2 and 3, the cutting belt 1 is constructed from two layers reinforced with belts 14. The inner belt 12 also has corresponding belts 15. Both belts 12, 14 are made of highly wear-resistant plastic. The cutting belt 1 has support plates 16 arranged at a distance for the cutting tools 2. In each case one of the support plates 16 is fastened to the cutting belt 1 by means of a support member 3 located under the cutting belt 1 in the manner shown in the drawing by means of two screw bolts 17. The support members 3 are laterally guided in the guide channel 6 on the side walls 18 and 19, which are formed on the side plates 10. With their underside 20, the support members 3 each rest on the inner belt 12, as the drawing shows.

In the first exemplary embodiment according to FIGS. 2 and 3, the rolling bodies 13 consist of rollers 13a, loosely arranged in a row in the guide channel 6 in the form of an endless loop, made of highly wear-resistant, pressure-resistant and in particular waterproof plastic. They are slightly conical on their sides 21, so that there is only a relatively small engagement surface laterally with the side walls 18, 19 of the guide channel 6. The rollers 13a roll on the bottom 22 of the guide channel 6, into which feeds 23 lead through the base body 7 and its web 8, through which water is introduced for the purpose of cooling and keeping the guide channel 6 clean and for lubricating the guide surfaces and the moving parts, that flows outwards. The diameter of the Rollers 13a and the length of the support members 3 are coordinated so that there are always at least two rollers 13a in engagement below each support member 3. In this way, the cutting pressure transmitted from the cutting tools 2 to the support members 3 is distributed to at least two rollers 13a during operation of the cutting arm. However, the use of two belts according to the invention in the form of the cutting belt 1 and the inner belt 12 anyway contributes to a distribution and equalization of the cutting pressure on the rollers 13a. The rollers 13a are securely guided and held together in the guide channel 6 laterally between the side walls 18, 19 and below on the floor 22 and above by the inner belt 12. The speed of the rollers 13a is only half as great as that of the inner belt 12 and the cutting belt 1 on their circulation around the cutting arm, whereby the centrifugal force acting on the rollers 13a is considerably reduced. Because of the three sizes, mass, radius and speed, which are decisive for the centrifugal force, the last-mentioned size is known to be square in the product to be formed, which is very essential for high-speed cutting machines.

The second exemplary embodiment according to FIGS. 4 and 5 differs from the previously described first exemplary embodiment as far as the invention is concerned by the design of the rolling bodies 13 as balls 13b which run in the guide channel 6 in the form of a double row, separated by a central web 24. The shape of the double row is chosen in order to ensure that the support members 3 and the inner belt 12 are supported against tilting. The ball solution has the advantage of a further reduction in the circumferential mass of the rolling elements 13 and a further reduction in the friction due to significantly smaller engagement surfaces with the bottom 22 and the inner belt 12 tion channel 6 is divided into two subchannels in this embodiment, the water supply lines 23a are correspondingly arranged in two rows.

In the second exemplary embodiment, the support members 3 have a metal jacket 25, and the cutting tools 2 are not formed in two parts, as in the first exemplary embodiment, but rather only in one part, as can correspond to the respectively selected frequency of successive cutting tools. For the rolling bodies 13 designed as balls 13b, the explanations for the first exemplary embodiment also apply in analogous transmission.

To avoid repetition, the possible variations that are listed in detail at the beginning of the description should not be mentioned again here. There is also no further explanation of the structure of the cutting arm because known technology can be used for this.

Claims (26)

1.Cutting arm for cutting machines for cutting stone, concrete, etc., on which in an open guide channel an endless flexible cutting belt, which is driven on the outside with cutting tools and on the inside with supporting members, rotates, the supporting members being mounted and guided in a longitudinally movable manner on the bottom and on the side walls of the guide channel and the lower part of each support member is designed for engagement with a corresponding toothing of a drive pinion at one end of the cutting arm, characterized in that the support members (3) rest on an endless flexible inner belt (12) which rests on rolling bodies (13) on the floor ( 22) of the guide channel (6). 2. Cutting arm according to claim 1, characterized in that the guide channel (6) forms a closed loop, the pinion-side reversing arc (11) in front of the drive pinion (4). 3. Cutting arm according to claim 1 or 2, characterized in that the inner belt (12) and the rolling body (13) on the side walls (18, 19) of the guide channel (6) are guided. 4. Cutting arm according to claim 1, 2 or 3, characterized in that the rolling bodies (13) consist of rollers (13a) which are arranged in a row one behind the other in the guide channel (6). 5. Cutting arm according to claim 4, characterized in that the rollers (13a) are rotatably mounted in the manner of a roller table in the guide channel (6). 6. Cutting arm according to claim 4, characterized in that the sides (21) of the rollers (13a) are slightly conical or spherical in shape. 7. Cutting arm according to claim 4 or 6, characterized in that the rollers (13a) are loosely inserted into the guide channel (6). 8. cutter arm according to claim 7, characterized in that the rollers on both sides have pins which engage in parallel to the bottom guide grooves on the side walls (18, 19) of the guide channel (6). 9. cutting arm according to claim 8, characterized in that the dimensions and distances of the pin and the guide grooves are chosen so that the pin does not touch the wall of the guide groove when the rollers (13a) are in contact with the bottom (22). 10. cutter arm according to one or more of claims 4 to 9, characterized in that the rollers (13a) each have an annular recess in the middle. 11. Cutting arm according to one or more of claims 4, 6 to 10, characterized in that the rollers (13a) are interconnected in the manner of a roller chain. 12. Cutting arm according to claim 11, characterized in that the connection consists of a curvilinear-flexible, longitudinally rigid strand with annular eyes arranged in the roller spacing for receiving lateral pins of the rollers. 13. Cutting arm according to claim 1, 2 or 3, characterized in that the roller body (13) consist of balls (13b). 14. Cutting arm according to claim 13, characterized in that the balls (13b) are arranged in two rows in the guide channel (6), which are separated from one another. 15. Cutting arm according to claim 14, characterized in that the balls (13b) are inserted loosely and are separated from one another by a partition (24). 16. Cutting arm according to claim 13 or 14, characterized in that the balls (13b) run in rows in cages. 17. cutter arm according to one or more of the preceding claims, characterized in that for cooling in particular the rollers body (13) and the inner belt (12) and the guide channel (6) water can be introduced into the lower section of the guide channel (6) by means of feeders (23, 23a). 18. Cutting arm according to claim 17, characterized in that the feeds open into the bottom (22) of the guide channel (6). 19. Cutting arm according to one or more of the preceding claims, characterized in that the rolling bodies (13) consist of plastic. 20. Cutting arm according to claim 19, characterized in that the rolling bodies (13) have a highly wear-resistant metal jacket. 21. Cutting arm according to one or more of the preceding claims, characterized in that the bottom (22) and the side walls (18, 19) of the guide channel (6) have a smooth, in particular polished and highly wear-resistant surface. 22. Cutting arm according to one or more of the preceding claims, characterized in that the support members (3) consist of a pressure-resistant, highly wear-resistant plastic. 23. Cutting arm according to one or more of the preceding claims, characterized in that the support members (3) have a metal jacket (25). 24. Cutting arm according to one or more of the preceding claims, characterized in that the support members (3) in cross section have the shape of an isosceles trapezoid with drawn-in end faces. 25. Cutting arm according to one or more of the preceding claims, characterized in that the diameter and the mutual spacing of the rolling elements (13) are matched to the length of the supporting members (3) and their spacing from one another such that the supporting members (3) under the Cannot tilt cutting pressure. 26. Cutting arm according to one or more of the preceding claims, characterized in that the inner belt (12) has belt inserts (15).

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