GB2189280A - Cutting machine safety device - Google Patents

Description

GB 2 189 280 A 1 SPECIFICATION transmitter being in principle of similar

construction, theconstruction comprising a slide member Device for preventing a collision between a cooperating with displacement pickups is swivellable loading ramp and an universally remarkable insofar as no seal ing gu ide mea ns is swivellable cutting arm 70 required. The slide member can even be supported with play on a housing or within a housing, and the

Background of the invention mechanical stress acting on such a slide member is,

Field of the invention in case of shocks, substantially lower as compared

The invention refers to a device for preventing a with a hydraulic cylinder-piston-aggregate. This collision between a swivellable loading ramp and a 75 applies also if, as is in correspondence with a cutting arm orcutting tool, which is swivellable preferred embodiment, the constructional part is around a horizontal axis and around a substantially designed as a tubular housing and the slide member vertical axis, of a cutting machine, in which are is inserted into the housing and is guided therein.

connected with the loading ramp and with the The use of electrical switches and, as is in cutting arm sensors for the relative swivelled 80 accordance with a particularly preferred position of the loading ramp and of the cutting arm. embodiment of the invention, of electrical switches notto betouched providesthe possibilityto usefully Description of thepriorart encapsulated, touch-free signal transmitters being,

Devices of the initially mentioned type and using for example, cast into synthetic plastics material and hydraulictransmitters can, for example, be taken 85 providing for a high operation safety. Such signal from AT-PS 366 773. In this known device, there is transmitters, which are cast into synthetic plastics connected one hydraulic cylinder-piston-aggregate material and operate without being mechanically each with the loading ramp orthe loading table, contacted, may also be actuated across non-metallic respectively, noting thatthe liquid forced out of each materials and a tubular housing may,forexample, respective cylinder of the hydraulic 90 consist of synthetic plastics material. The signal cylinder-piston-aggregate is supplied to a common transmitters working without being mechanically receiving part, which effects shut-down of the drive contacted are water- tight, have a relatively good heat means of the cutting arm and of the loading ramp, resistance, are substantially wear-resistent and need respectively. The common receiving deviceforthe substantially no maintainance work, so that a long hydraulic transmitters itself was again designed as a 95 useful life isfor sure. No adverse effectcan be hydraulic cylinder-piston-aggregate and the device produced by dust generated during the cutting work, designed in this manner is, however, of relatively whereas sealing problems may arisewhen using as great accuracy but also of great sensibility underthe displacement pickups hydraulic stress of mining work. Forthese reasons, most cylinder-piston-aggregates in case of a strongly frequently mechanical solutionsforthe problem 100 dust-loaden atmosphere. As a whole,there isthus were preferred in the past, and a corresponding provided a simple device of low space requirement mechanical device for preventing the collision of a and of extremely high operating safety, with which cutting arm with a loading ramp can, for example, be device the collision between a swivellable loading taken from AT-PS 374 888. In this known protective ramp and a universally swivellable cutting arm can devicetherewere provided mechanical control 105 reliably be prevented.

elements being mechanically coupled tothecutting According to a preferred embodimentofthe arm and to the loading ramp, respectively, noting deviceaccording tothe invention,the displacement that both mechanical control elements are pickup is designed as a capacitive or inductive mechanically connected with interposition of a proximity switch and installed within thewall of the switching member. In practice, this known device 110 tubular housing. A plurality of such touch-free was a spring-loaded slide valvewhich was directly switches can be provided along the displacement interconnected into the hydraulic conduits. path of the slide member, noting thatthe tubular housing is preferably designed such thatthe wall of Summary of the invention thetubular housing has a plurality of radial recesses

L 50 The invention now aims atfurther developping a 115 or perforationsfor receiving the electrical switches.

device of the initially mentioned type such that it has, According to a particularly simple embodiment of with accompanying lowspace requirement, a great the invention,the arrangement is such that a slide mechanical stability and shows an only low member is connected with the cutting arm and is susceptibility to troubles also underthe stress of swivellable in parallel relation relativeto afront mining work. Forsolving thistaskthe invention 120 surface, comprising the switches, of the housing.

essentially consists inthatone slide membereach is Such an embodiment may havetheform of a arranged between loading ramp and machine frame fishplatewhich can also laterbefixedto a cutting and between cutting arm andthe bearing supportof arm, so that existing cutting machines can in a the cutting arm and is shiftably guided relativeto a simple manner besupplemented.

constructional part equipped with at least one 125 displacement pickup, in particular an electrical Brief description of the drawing switch. In the following, an electrical valve can be In the following, the invention is explained in actuated or a signal device can be made operative in greater detail with reference to embodiments shown dependence on the position of the switch of the in the drawing.

displacement pickup. As compared with a hydraulic 130 In the drawing 2 GB 2 189 280 A 2 Figure 1 shows a side elevation of a cutting sufficient to provide for controlling the swivel machine equipped with the device according to the cylinder swivelling the cutting arm 6 in direction of invention, the twin arrow 8 and for controlling the swivel Figure2 shows an axial section through a slide cylinderfor lifting and lowering the loading table 4 member serving as a transmitter and being used in 70 when swivelling same around the swivel axis 3 the embodiment according to Figure 1, insofar as no swivelling movement around the Figure 3 shows a modified embodiment, vertical axis 10 is considerated. In dependence on the Figure 4shows a section along line M1V of Figure design of the surface of the loading ramp it may be 3 and possible that a collision at lateral areas of the loading Figure 5shows a further modified embodiment of 75 ramp takes place earlier or later than in central areas a transmitter comprising a slide member. of the loading ramp. By means of the transmitter slide member 13 shown in Figure 1, only Detailed description of thepreferred embodiments approaching movement in vertical direction is

In Figure 1 there is shown a cutting machine 1 detected, but by means of analogous slide members which is movable on a caterpillar (R.T.M) chassis 2. A 80 it is additionally possible to detect any swivelling loading ramp or a loading table 4, respectively, is movement around the vertical axis and thus any swivellably linked to the machine frame 5 for being swivelling movement of the cutting arm in horizontal swivellable around a swivel axis 3 being arranged in direction. The minimum configuration of essentially parai lel relation to the running surface of constructional parts shown in Figure 1 can do with a the caterpillars of the caterpillar chassis 2. Cutting 85 low number of identical constructional parts and heads 7 are rotatably supported on a cutting arm 6 thus provides for a high degree of operation safety.

being swivellably supported for swivelling The particular embodiment of such a transmitter movement essentially in vertical direction in the slide member shown in Figure 2 is of extremely sense of thetwin arrow 8. The swivel axisfor simple construction and has an extremely low upwardly and downwardly swivelling the cutting 90 susceptibility to operation troubles. Thetubular arm 6 is designated bythe reference numeral 9. housing 15 may consist of metal butalso of synthetic Furthermore, an essentially vertical swivel axis 10 is plastics material, noting that, if the housing is made provided for making the cutting arm 6 universally of synthetic plastics material, thetouch-free signal swivellable, and the cutting arm 6 is supported on transmitters can also be mounted on the outer side the machine frame 5 by means of a bearing disc 95 of the tube and the radial perforations 16 are not means, the housing of which is designated by 11. necessary.

Within the rear area, there is provided a removal A modified embodiment of a transmitter slide conveyor means 12 forthe cut or excavated material, member can be taken from Figure 3. In this case,the respectively. slide member 14 is formed of a plate-like protrusion Between the machine frame 5 and the loading 100 of the cutting arm, the swivel axis of which forthe table orthe loading ramp 4, respectively, there is swivelling movement around a substantially arranged a transmitter slide member 13 comprising horizontal axis in vertical direction is again a slide member 14 being swivellably linked with the designated bythe reference numeral 9. On occasion loading table or, respectively, the loading ramp as of such a swivelling movement of the cutting arm in well as a tubular housing 15 swivellably linked tothe 105 direction of thetwin arrow 18,the slide member 14is machineframe 5. An analogous transmitters] ide swivelled and covers in dependence on the swivelled member 13 of substantially identical construction is position a numberof inductive orcapacitive sensors swivellably linked to the housing 11 of the bearing 19. Also in this embodiment, the sensors 19 are disc means and to the cutting arm 6, noting thatthe mounted within a housing 20 and extend, as can be slide member 14 is also in this case linked to the 110 taken from Figure 4, through thatwall 21 of the cutting arm and the tubular housing 15 is linked with housing which is adjacentthe slide member 14. The the bearing housing of the bearing disc means. signal conduits are again designated by 17. In In the representation according to Figure 2,the dependence on the number and the extent of transmitter slide member 13 is shown in a greater covering of the sensors 19 covered bythe slide scale. The wall of thetubular housing 15 has a 115 member 14,there results a different signal. The slide plurality of radial perforations 16, intowhich member 14 can, as is shown in Figure 5, also be touch-free signal transmitters can be inserted. The shifted in shifting direction 22 like a lid over slide member 14 isformed of an iron rod which is sequentially arranged sesors 19 and, respectively, be inserted intothe interior of thetubular housing 15 drawn off these sensors, noting that also inthis case and is supported with playwithin the interior of the 120 it is possibleto gradually determinethe position.

tubularhousing. Such slide members 14 require an only low precision The number of radial perforations 16 can be of the guide means and are substantially insensible selected in correspondence to the desired switching against shocks. In this case, guiding need not be accuracy. The selected number of touch-free effected on constructional parts carrying the electrical switches inserted into the perforations 16 125 sensors, but can also be effected by rigidly is, via signal conduits 17, connected with an connecting the slide members 14with the cutting electrical switch unit, not shown, via which is arm orwith the loading ramp.

controlled in usual mannerthe hydraulic drive The signals of thetransmitter slide members can means for swivelling the cutting arm orthe loading logically be combined one with the other, so thatan ramp, respectively. In this case, it is in principle 130 inadmissible approach is detected in any swivelled 3 GB 2 189 280 A 3 position of the loading ramp and of the cutting arm and the swivel drive means of the cutting arm and of the loading ramp is deactivated, for example by using solenoid valves. The transmitter slide members can be arranged such that signals are obtained already long before any danger of collision and approaching movement of cutting arm and loading ramp can be monitored on corresponding signalling equipments over a long distance.

Claims (6)

1. Device for preventing a collision between a swivellable loading ramp (4) and a cutting arm (6) or a cutting tool (7), which is swivellable around a horizontal axis (9) and around a substantially vertical axis (10), of a cutting machine (1), in which are connected with the loading ramp (4) and withthe cutting arm (6) sensorsforthe relative swivelled position of the loading ramp and of the cutting arm, characterized in that one slide member (14) each is arranged between loading ramp (4) and machine frame (5) and between cutting arm (6) and the bearing support (11) of the cutting arm and is shiftably guided relative to a constructional part (15, 20) equipped with at least one displacement pickup, in particular an electrical switch.

2. Device as claimed in claim 1, characterized in thatthe constructional part is designed as a tubular housing (15) and in thatthe slide member (14) is guided while being inserted into the housing.

3. Device as claimed in claim 1 or 2, characterized in thatthe electrical switch is designed as a touch-free switch.

4. Device as claimed in claim 3, characterized in that a slide member (14) is connected with the cutting arm (6) and is swivellable in parallel relation to a front surface (21), comprising the switches (19), of the housing (20).

5. Device as claimed in claim 1 or2, characterized in thatthe displacement pickup is designed asa capacitive or inductive proximity switch and is installed into the wall of the tubular housing (15).

6. Device as claimed in anyof claims 1 to 5, characterized in that the wall of the tubular housing (15) has a plurality of radial recesses or perforations (16) accommodating the electrical switches.

Printed for Her Majesty's Stationery Office by Croydon Printing Company (U K) Ltd,8187, D8991685. Published by The Patent Office, 25Southampton Buildings, London, WC2A l AY, from which copies may be obtained.