GB2316349A - Device for shearing off weld-deposit projections in rail joints - Google Patents

Abstract

The device for cutting off weld-deposit projections of a rail joint weld, has two shearing blades (13, 14) which can be actuated by pressure medium arranged for the pincer-like shearing-off of the weld-deposit projections at least in the region of a rail head (31). A closed frame which consists of longitudinal members (1, 2) and end cross-pieces (3, 4) carries the shearing blades (13, 14) and a piston/cylinder unit (11, 12) for actuating them. One shearing blade (13) is arranged on the side of the cross-piece (3) facing the inside of the frame, and the other shearing blade (14) is arranged on the side of a sliding cross piece (6) movable relative to the frame. The longitudinal members (1, 2) being configured as guide elements for the movement of the cross-piece (6). The device is characterized in that the longitudinal members (1, 2), the cross-pieces (3, 4) and the piston/cylinder unit (11, 12) are made of high-strength steel or an aluminium alloy.

Description

DEVICE FOR SHEARING OFF WELD-DEPOSIT PROJECTIONS IN RAIL JOINT WELDS The invention relates to a device for shearing off weld-deposit projections in rail joint welds.

It is known that a joint weld between two rail ends facing one another in the laid track is very simple to make by aluminothermic methods by introducing a molten weld deposit into the gap separating the rail ends and surrounded on the outside by a mould device. Here, the molten weld deposit is produced by igniting an aluminothermic mixture consisting of aluminium particles and iron-oxide particles, in which case the iron oxide is reduced in the course of the highly exothermic reaction, a slag containing aluminium oxide floats on the surface, and the molten iron is poured in the gap. A considerable advantage of this process, which is of great importance for practical manipulation on site, consists in the fact that no external power source is required for preparing the molten weld deposit.

The space to be filled by the weld deposit is limited by the end faces of the rail ends opposite one another and in addition by the longitudinally split mould device covering the gap on both sides and as a rule having at least one foot riser and one head riser. However, relative to the profile of the rail ends to be joined, weld-deposit projections result, which necessitate reconditioning at least in the region of the functional surfaces of the rail head, so that profile adaptation of the weld-deposit region to the profile of the rail ends to be joined is aimed at in the region of the rail head. The risers, which have predetermined breaking points in the region joined to the rail profile, may be removed at the same time in the course of this reconditioning.

For energy reasons, it is considered to be appropriate to remove the substantial portion of the weld-deposit projection while still in the hot state by shearing off said weld-deposit projection, so that merely a finishing operation via a subsequent grinding operation has to be carried out in order to maintain predetermined dimensional tolerances with regard to the rail-head profile in the weld-deposit region.

DE 26 43 260 C2 discloses various forms of devices suitable for carrying out the shearing operation under site conditions, namely in the laid track, in which devices shearing blades are provided which, to remove the weld-deposit projections, are hydraulically movable pincer-like towards one another and away from one another on both sides of the same, a closed frame being provided for absorbing the reaction forces developed by the shearing operation, to which frame two or more piston/cylinder units are attached. An embodiment of such a device disclosed by this publication consists of two longitudinal members connected at the ends by cross-pieces and extending parallel to one another, two piston/cylinder units being attached to the one cross-piece, the piston rods of the said piston/cylinder units extending parallel to one another and carrying a further movable cross-piece. Both the last-mentioned cross-piece and the cross-piece opposite said cross-piece and fastened to the longitudinal members each carry a shearing blade adapted to the rail-head profile to be worked. The longitudinal members are designed as tubular or angular guide elements for the piston/cylinder units and hold-downs are located on both cross-pieces, connecting the longitudinal members, in each case on both sides of the rail profile, which hold-downs are intended and configured for engaging underneath the rail head so that the vertical reaction forces developed by the shearing operation are also reliably absorbed by the rail profile. At the same time, the cutting height of the shearing blades is set by these hold-downs. The operation of this device requires additional equipment for providing a hydraulic medium under a requisite pressure, although this additional equipment does not form a constructional unit with the device. In accordance with the thickness, but also with the temperature, of the weld-deposit projection to be sheared off, both the longitudinal parts and the said cross-pieces together with working cylinders have to be designed for absorbing high reaction forces, so that these parts are normally made of steel, e.g. structural steel.

However, this leads to the design of a device of comparatively high mass, the manipulation of which on site turns out to be laborious. Now the problem of the reduction in weight has also formed the basis for the conception of this known device - however, the measures proposed for this purpose are restricted to varying the number of piston/cylinder units to be provided for the shearing-off operation. However, there are relatively narrow limits to a reduction in mass by this method due to the reaction forces predetermined by the shearing operation. In addition, there is also the fact that the shearing operation in some cases is intended to cover not only the weld-deposit projection in the region of the rail head but also in the region of further parts of the rail profile and the risers.

Against this background, in particular in order to avoid physiological damage caused by the continued manipulation of relatively heavy masses, there is therefore a great need to provide a device for shearing off weld-deposit projections which is improved with regard to its operating features.

According to the present invention there is provided a device for cutting off weld-deposit projections of a rail joint weld, having two shearing blades which can be actuated by a pressure medium and are intended and arranged for the pincer-like shearing-off of the weld-deposit projections at least in the region of a rail head, and a closed frame which consists of longitudinal members and first and second fixed cross-pieces, wherein the closed frame supports the shearing blades and at least one piston/cylinder unit for actuating the shearing blades, wherein one shearing blade is arranged on the side of the first cross-piece facing the inside of the frame, and the other shearing blade is arranged on the side of a moveable cross-piece facing the first cross-piece, wherein the moveable cross-piece is also connected to the piston/cylinder unit and is movable relative to the frame, wherein the longitudinal members act as guide elements for the movement of the moveable cross-piece, and wherein the longitudinal members, the cross-pieces and the piston/cylinder unit are made of high-strength steel or an aluminium alloy.

In the present invention special materials, e.g. high-strength fine-grained steel or an aluminium alloy, e.g. F53, are used for the parts determining the mass of the device, in order to utilize the strength of these materials, which is increased compared with the materials used hitherto, in order to correspondingly reduce the mass.

The purpose of these measures is to facilitate the manipulation of this device, namely the transport, the mounting of the device on the laid track to be worked, and the subsequent removal of the device and therefore to relieve the strain for the person working with this device in practice. For example, the longitudinal members and the cross-pieces may be made of the said fine-grained steel and the at least one piston/cylinder unit may be made of an aluminium alloy, so that a homogeneous design of the entire device in terms of materials is not absolutely necessary.

However, a homogeneous design in terms of materials is expedient. Therefore, the parts substantially determining the mass of the device are preferably made of the said high-strength special materials - provided this is technically possible and justifiable in terms of cost.

Furthermore, according to the features of claim 2, hold-downs, hand grips and guide stirrup are made of high-strength steel or an aluminium alloy. In terms of design and function, these components correspond to components known per se. By virtue of the fact that these components are made of high-strength special materials, this helps to reduce the mass further.

The features of claims 3 and 4 are directed towards further measures for reducing the mass of the device. Both the hold-downs and the guide stirrup are made of the said high-strength materials, which equally applies to the mounting plates attached to the cross-pieces and functioning as supports for the hold-downs and the guide stirrup. At the same time, a reinforcing effect on the cross-pieces comes from the mounting plates.

According to the features of claims 5 and 6, the components of the device which are mentioned there and are to be connected to one another are welded to one another if they are made of a high-strength steel. This is the most expedient type of connection. In addition to these said components there are of course hand grips and guide elements for the hold-downs and the guide stirrup. If the said parts are made of a high-strength aluminium alloy, a screwed connection is also suitable in principle, although the use of high-strength steel and the welding of the said parts will be preferred.

The features of claims 7 to 12 are directed towards a further improvement in the operating features inasmuch as a safety risk which is generally present is removed according to said features. As a function of the admission of pressure medium to a piston to which pressure medium can be admitted on both sides, pressure differences result on both sides of the piston on account of different areas to which the pressure medium can be admitted, which pressure differences, when pressure medium is fully admitted on one side of the piston to its piston area and the piston area opposite the piston area to which pressure medium is fully admitted is reduced by the cross-section of the piston rod, may lead to inadmissible excess pressures in the space allocated to the reduced piston area, namely when the non-return valve arranged in the connecting line to a tank is closed on account of an incorrect coupling state of a connecting line. The pressure-relief valve used here ensures that such an excess pressure is avoided, in which case the opening pressure of the said pressure-relief valve can correspond, for example, to the highest permissible pressure which can be tolerated in the connecting lines between the directional control valve and the pressure generator. The directional control valve and the pressure-relief valve expediently form a constructional unit which according to the invention is likewise made essentially of high-strength special materials of the aforesaid type.

The features of claims 13 and 14 are directed towards the constructional configuration of the device, in which case use is essentially made of known design elements, which, however, are made of the high-strength materials mentioned at the beginning.

The invention is described in more detail below with reference to the exemplary embodiment reproduced schematically in the drawings, in which: Fig. 1 shows a plan view of the device according to the invention; Fig. 2 shows a side view of the device according to arrow II in Fig. 1; Fig. 3 shows a simplified end view of the device according to arrow III in Fig. 1; Fig. 4 shows an end view of the device according to arrow IV in Fig. 1 with representation of the rail head to be worked; Fig. 5 shows a partial representation of the hydraulic circuit allocated to the device.

Reference is first of all made below to the diagrammatic representations of Figs. 1 to 4.

The device according to the invention is characterized by an outer rigid frame which consists of two longitudinal members 1, 2 which extend parallel to one another and are connected to one another at the ends via firmly arranged cross-pieces 3, 4. As Figs. 3, 4 show, the longitudinal members 1, 2 have an angle profile and are arranged facing one another in the said frame. They form a guide for a movable cross-piece 6 in the direction of the longitudinal members 1, 2, thus in the direction of the arrows 5, which cross-piece 6 extends parallel to the cross-pieces 3, 4.

All cross-pieces 3, 4, 6 are of plate-like design and extend perpendicularly to the base plane containing the longitudinal members 1, 2. The sections of the movable cross-piece 6 which face the longitudinal members 1, 2 are designed with regard to engagement with the angle profile of the longitudinal members, so that a guidance function can be performed via the latter during a movement in the direction of the arrows 5.

A piston/cylinder unit 7, 8 extends in each case between the facing sides of the movable cross-piece 6 and the fixed cross-piece 4, specifically at their marginal regions, the respective cylinders of which piston/cylinder units 7, 8 are connected at the end face to the movable cross-piece 6 and the respective piston rods of which are connected to the fixed cross-piece 4. Pressure medium can be admitted on both sides to the cylinder/piston units 7, 8, and 9 designates a 4/3-way directional control valve, the housing of which is fastened to the cylinders of the piston/cylinder units 7, 8 in a suitable manner (not shown diagrammatically in more detail). The directional control valve 9 can be actuated by a hand lever 10 and is connected via connecting lines (not shown diagrammatically) to a pressure generator containing a tank, preferably to a pump which can be motor-driven. The connections of the directional control valve 9 serving to connect the pressure generator as well as the connecting lines to be connected to the pressure generator are preferably equipped with quick-disconnect couplings as well as non-return valves, which prevent the pressure medium from escaping if a connecting line is detached.

Connecting lines between the piston/cylinder units 7, 8 and the directional control valve 9 are each designated by 11, 12, and a movement of the cross-piece 6 in the direction of the arrows 5 can be effected by alternative admission of pressure medium to said connecting lines 11, 12.

Both the fixed cross-piece 3 and the movable cross-piece 6 carry shearing blades 13, 14 on their sides facing one another, which shearing blades 13, 14 are intended for gripping the rail head to be worked and are set up at least for a shearing-off operation in the region of the travel surfaces and the flanks of the rail head. The shearing blades are preferably detachably fastened to the said cross-pieces so that different blade profiles are used, including in particular those which are set up for shearing off weld-deposit projections in the region of the rail head and likewise for shearing off risers.

15, 16 each designate mounting plates, which are fastened to a centre region of the cross-pieces 3, 6 - in each case on their sides remote from the shearing blades 13, 14. The mounting plates 15, 16 extend essentially perpendicularly to the planes of the cross-pieces 3, 6. The mounting plate 15 has a centre section 15' which extends parallel to the base plane defined by the longitudinal members 1, 2, sections 15'', 15''' of dimensions identical to one another and angled relative to the said base plane extending on this centre section 15'.

The mounting plate 16 merely consists of a centre section which extends parallel to the said base plane.

The centre section 15' of the mounting plate 15 and the mounting plate 16 serve in like manner to attach hold-downs 17, 18 which are made identical to one another.

A hold-down 17, 18 is allocated to each mounting plate 15, 16, which hold-downs 17, 18 are located at the same distances from, but on different sides of, a vertical centre plane 19. The hold-downs 17, 18 are intended for engaging underneath the rail profile to be worked and thus for transmitting vertical reaction forces, resulting from the shearing process, to the rail profile.

Each hold-down 17, 18 consists of a threaded bolt 20, on the one top end of which a handle 21 is arranged and on the other bottom end of which a holding element 22 is arranged which is intended and designed for engaging underneath the rail profile. Each threaded bolt 20 is held in a guide cylinder 23 which extends perpendicularly to the centre section 15' or to the mounting plate 16 and is continued via corresponding bores in the said mounting plates. Each guide cylinder 23 is provided with a threaded section at a suitable location, here a nut firmly connected to said location and in engagement with the thread of the threaded bolt 20, so that the holding element 22 can be lowered or raised relative to the plane of the mounting plate by turning the threaded bolt.

24, 25 designate hand grips, which are fastened to the outsides of the longitudinal members 2, 1 in a suitable manner, in particular welded to the longitudinal members 2, 1, and serve to manually transport the device.

26 designates a roughly U-shaped stirrup, the vertically extending legs 26', 26'' of which form at their lower ends guide surfaces 27 intended for bearing against the rail profile to be worked. To hold the stirrup or guide stirrup 26, guide cylinders 28 are provided which accommodate the side legs 26', 26'' and which in turn are arranged on mounting plates 29 which are fastened to the side of the cross-piece 4 facing the cross-piece 6. The guide cylinders 28 are arranged in alignment with corresponding bores in the mounting plate 29 so that the guide surfaces 27 extend below the mounting plate 29.

The stirrup 26 can be fixed in the guide cylinders 28 in a suitable manner.

The cross-pieces 3, 4 and 6 each have recesses on the underside, specifically in symmetrical relationship to a vertical centre plane 30, the clear width of which recesses is dimensioned to be greater than the profile of the rail head 31 to be worked, so that no vertical supporting forces are transmitted to the rail head 31 directly via the cross-pieces 3, 4 and 6 during the shearing operation on the rail head 31.

As mentioned at the beginning, pressure medium can be admitted on both sides to the piston/cylinder units 7, 8, the directional control valve 9 being connected to a pressure generator in a manner not shown in Figures 1 to 4 of the drawing. For safety reasons, the pressure generator is normally equipped with a pressure-relief valve in order to protect components of the pressure generator, but also to protect the connecting lines to the directional control valve, from mechanical overload. However, an additional safety aspect is taken into account in the pressure-medium system of the device according to the invention and to this end reference is made below to Figure 5 of the drawing.

32, 33 in Fig. 5 designate connecting lines which can be connected to the connecting lines 11, 12 via the directional control valve 9 in accordance with its operating position in order to effect a corresponding movement of the shearing blade 14 in the direction of the arrows 5. Here, the connecting line 32 designates a pressure line, whereas the connecting line 33 designates a return line.

34, 35 in turn designate connecting lines which lead to a pressure generator, the connecting line 34 designating the pressure line and the line 35 designating the line leading to a tank. At their end points facing one another, all connecting lines 33 to 35 have non-return valves 36 and can be connected to one another via coupling elements 37, of which only one is indicated diagrammatically. The connecting lines are closed at their end points via the non-return valves 36 in each case in the uncoupled state, so that undesirable escape of pressure medium is prevented.

The coupling element 37, however, is made in such a way that the non-return valves 36 are functionless in the coupled state.

38 designates a pressure-relief valve, which is set to a defined maximum pressure dependent, inter alia, on the characteristics of the directional control valve 9. The purpose of this pressure-relief valve 38 is to be seen in combination with the non-return valves 36 at the end points of the connecting lines 32, 33, which are integrated in the housing of the control valve 9, and consists in the following: During the shearing feed of the shearing blade 14, pressure medium is fully admitted to the piston areas of the piston/cylinder units 7, 8, in the course of which the pressure medium is fed back via the connecting line 33 into the tank of the pressure generator in the coupled state of the connecting line 35 in accordance with the feed. The maximum permissible pressure of the line system is determined here by a safety valve allocated to the pressure generator. If, for whatever reason, a coupling state does not exist between the connecting lines 33, 35, so that the non-return valves 36 allocated to these lines are in the closed state, different pressures develop on both sides of the pistons of the piston/cylinder units 7, 8 while pressure medium continues to be admitted to the connecting line 32, since, on the side remote from the pressure-side piston area, there is only a piston area reduced by the cross-section of the piston rod. Therefore a pressure can build up in the connecting line functioning as return line, including all parts of the directional control valve which are to be considered as return, which pressure turns out to be higher than the pressure in the connecting line 32 by a factor determined by the front- and rear-side pressure ratio of the effective piston areas, which may lead to mechanical damage, inter alia, of the directional control valve 9 as a result of an overload. In this case, the pressure-relief valve 38 ensures that the pressure in the connecting line 33 cannot exceed a defined value, so that, for example, the maximum pressure predetermined on the pressure-generator side is decisive for the entire line system of the pressure medium and a local build-up of a pressure increased in contrast thereto is ruled out.

The longitudinal members 1, 2, the cross-pieces 3, 4 as well as the mounting plates 15, 16 and 29 are made, for example, of a high-strength fine-grained structural steel and are welded to one another. The movable cross-piece 6, the hold-downs 17, 18, the hand grips 24, 25, the stirrup 26 and the connecting lines 11, 12 may likewise be made of such steel. The directional control valve 9 including the piston/cylinder units 7, 8 is made entirely or at least substantially of a suitable aluminium alloy, e.g. F53.

However, these parts may also be made either entirely or substantially of the said high-strength steel.

To use the device, it is placed on the rail head to be treated on both sides of the weld-deposit projection to be sheared off and is fixed by adjusting the hold-downs 17, 18, namely in such a way that their holding elements 22 engage under the rail head on both sides of the centre plate 19. In this phase, the device is supported in the vertical and lateral direction by the shearing blades 13, 14 in combination with the stirrup 26. The aim is to shear off the weld-deposit projection down to a height of 1 to 2 mm, in which case this residual projection is subsequently to be removed by grinding or another abrasive machining operation. The hold-downs 17, 18 ensure that shearing-off down to the said residual projection takes place. By subsequent admission of pressure medium to the piston/cylinder units, the cross-piece 6 is moved in the direction of the weld-deposit projection to be worked until it comes to bear against the latter, and during the further extension of the piston/cylinder units the shearing blade 13 is also drawn towards the weld-deposit projection. This and the subsequent shearing movement characterized by the two shearing blades 13, 14 moving pincer-like towards one another, during which shearing movement the weld-deposit projection is sheared off down to the said residual size, is effected under lateral guidance by the profile of both the shearing blades 13, 14 and the stirrup 26. After the shearing operation is complete, pressure medium is admitted to the piston/cylinder units 7, 8 in the opposite direction by appropriate actuation of the hand lever 10, whereupon the piston/cylinder units 7, 8 return into their initial position shown in the drawings.

Compared with the known embodiments, the device according to the invention is distinguished by a significantly lower mass and therefore improved ease of manipulation. This is achieved by the use of materials high-strength steels or suitable aluminium alloys - but also by design methods by virtue of the fact that mechanically highly stressed parts, such as, for example, the cross-pieces 3, 4, 6, are considerably stiffened by the mounting plates attached to them. In addition, the shearing blades, in particular during their movements initiated by means of the piston/cylinder units 7, 8, are guided in a precise manner along the rail profile to be worked.

Finally, safety aspects in particular, in combination with the control of the pressure medium, are also taken into account in the device according to the invention, the build-up of an inadmissibly high pressure in the region of the directional control valve being prevented in the event of an unsatisfactory coupling state of the return line.

Claims (15)

1. A device for cutting off weld-deposit projections of a rail joint weld, having two shearing blades which can be actuated by a pressure medium and are intended and arranged for the pincer-like shearing-off of the weld-deposit projections at least in the region of a rail head, and a closed frame which consists of longitudinal members and first and second fixed cross-pieces, wherein the closed frame supports the shearing blades and at least one piston/cylinder unit for actuating the shearing blades, wherein one shearing blade is arranged on the side of the first cross-piece facing the inside of the frame, and the other shearing blade is arranged on the side of a moveable cross-piece facing the first cross-piece, wherein the moveable cross-piece is also connected to the piston/cylinder unit and is movable relative to the frame, wherein the longitudinal members act as guide elements for the movement of the moveable cross-piece, and wherein the longitudinal members, the cross-pieces and the piston/cylinder unit are made of high-strength steel or an aluminium alloy.

2. A device according to claim 1, further comprising hand grips for use in transporting the device, hold-downs which, in use, engage underneath the rail head in a positive-locking manner, and a guide stirrup for laterally engaging around the rail head, in use, wherein the hand grips, hold-downs & guide stirrup are made of a high-strength steel or an aluminium alloy.

3. A device according to claim 2 wherein two holddowns are provided, wherein the hold-downs are arranged adjacent to the shearing blades on different sides of a vertical centre plane of the device, the guide stirrup is arranged adjacent to the second fixed cross-piece, and the hold-downs as well as the guide stirrup are made of high-strength steel or an aluminium alloy.

4. A device according to claim 3, wherein a mounting plate is attached to each of the cross-pieces, which mounting plates extend essentially perpendicularly to the planes of the cross-pieces, wherein the mounting plates each form supports for each of the hold-downs and the guide stirrup respectively, and the mounting plates are made of high-strength steel or an aluminium alloy.

5. A device according to any one of claim 4, further comprising a welded joint between the longitudinal members, made of high strength steel, the fixed cross-pieces and the mounting plates attached to the fixed cross-pieces.

6. A device according to any one of claims 4 or 5, further comprising a welded joint between the movable cross-piece, made of high-strength steel, and the mounting plate to which it is attached.

7. Device according to any one of claims 1 to 6, wherein said pressure medium can be admitted on both sides of the piston/cylinder unit.

8. A device according to any one of claims 1 to 7, wherein connection lines are provided for coupling the pressure-medium system of the device to a pressure generator and a tank, and which end in non-return valves which are in the closed position in the uncoupled state of connecting lines leading to the pressure generator and the tank.

9. A device according to claim 7 or 8 wherein the pressure-medium system includes a directional control valve.

10. A device according to claim 9, wherein a pressure-relief valve is provided which limits the pressure difference between a pressure line and a return line, between the directional control valve and the piston/cylinder unit and

11. A device according to claim 10, wherein the directional control valve and the pressure-relief valve are made at least substantially of high-strength steel or an aluminium alloy.

12. A device according to claim 10 or 11, wherein the pressure-relief valve is combined with the directional control valve to form a constructional unit, and the constructional unit is firmly connected to the frame.

13. A device according to any one of the preceding claims, wherein the longitudinal members have an angle profile, the inner surfaces facing one another, the legs of the profiles of the two longitudinal members forming guide surfaces for the movable cross-piece.

14. A device according to claim 13, wherein two piston/cylinder units are connected to the lateral marginal regions of the second fixed cross-piece and the movable cross-piece and are controllable together via the or a directional control valve, the piston/cylinder unit having parts which are movable relative to the second fixed cross-piece and which interact with the guide surfaces of the longitudinal members and are symmetrically arranged, relative to the vertical centre plane, of the device.

15. A device substantially as described herein with reference to Figures 1 to 5 of the accompanying drawings.