GB1596381A - Cutting machines including a table - Google Patents

Description

(54) IMPROVEMENTS IN OR RELATING TO CUTTING MACHINES INCLUDING A TABLE (71) I, HEDE NELSON AKTIESELSKAB, a Company with Limited Responsibility registered under the Laws of Denmark, of Godsbanegade 2, Horsons, Denmark, do hereby declare the invention for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to cutting machines including a steel plate cutting table of the type having a top grate structure for supporting the plate to be cut and an overhead torch system including a movable, normally automatically controlled or guided plasma torch, or a number of such torches, operable to cut the steel or alloy plate according to any desired pattern. In many cases the large cutting tables are not provided with means for exhausting the fume and smoke generated when the burner tools are operating, and a resulting considerable contamination of the air in the workshop is not unusual. However, exhaust systems have been suggested, both for overhead mounting and located beneath the support grating.

If the plate blank covers the entire cutting table it will be sufficient to make use of a relatively small exhaust unit, since the air flow requirements would then be limited, but in practice it is necessary to design the exhaust system in such a manner that it is effective also when the cutting table is partly uncovered by the blank. Of course, it would be possible to make use of an extremely powerful exhaust system, but as the tables are usually rather large this would be an uneconomical solution of the problem.

In order to attack the problem it has already been suggested to divide the exhaust system into a number of parallel zones extending e.g. crosswise of the cutting table and to make the zones selectively operable in response to photo-electric sensor means sensing the occurrence of the torch flame below the plate blank in the particular zone, whereby the zone is automatically connected to a suction duct manifold extending along one side of the cutting table and communication with the various exhaust zones through holes which are closable by means of pneumatically operated doors hinged at one side or end and actuated by means of the said photoelectric sensors. The exhaust zones are defined between transverse partitions and between the support grating and the bottom surface underneath the table, and it is advantageous of course, that the exhaust means should not steadily exhaust the air from all under the table, but only from the zone or zones above which the torch or torches are actually operating.

However, the general sucking out of air from one end of the respective exhaust zones still requires a high capacity of the exhaust means, and even the heavier contaminants, moreover, are liable to follow the air flow, whereby considerable air clearing problems will be involved.

Embodiments of this invention seek to provide a cutting machine, in which the smoke and particulate contaminants resulting from the operation of the torches may be exhausted by a relatively small exhaust power and without the particulate contaminants being liable to be brought along with the air flow.

According to the invention there is provided a cutting machine including a table having a top grate structure for supporting plate material to be cut and an overhead torch system including a movable plasma torch to effect the cutting, exhaust means being provided underneath the top grate and comprising a series of parallel chamber portions defining respective exhaust zones, means for connecting the respective zones to means for exhausting air therefrom, wherein each exhaust zone as defined between opposed walls or partitions underneath the support grating comprises a tray member extending along the zone so as to have its bottom located at a level below the grating and spaced above the absolute bottom of the zone and so as to have upright side portions spaced somewhat from the respective walls or partitions, the space underneath the tray bottom communicating with said air exhausting means permanently or through selectively openable valve means.

Here-by the exhaust means will be operable to create an underpressure in the space underneath the said tray, and the air above the zone will generally be sucked downwardly towards the tray by virtue of the suction between the tray sides and the adjacent walls or partitions, whereby most of the particulate contaminants will be deposited in the tray while the smoke will be brought along with the air flow to the suction means. Thus, the exhaust zone is not entirely open upwardly, whereby a relatively weak air flow is sufficient for ensuring an even suction action throughout the length of the zone, and most of the particulate contaminants will be deposited in the tray from which they are easily removable.

According to a further feature of the invention the said spaces between the tray sides and the rigid walls or partitions are preferably covered by inclined top plate means spaced above the top edges of the tray sides whereby the particulate contaminants cannot fall down directly into the said spaces.

An embodiment of the invention will now be described by way of example with reference to the accompanying drawing, in which: Figure 1 is a perspective view of a cutting table according to the invention, Figure 2 is a schematic top view thereof, Figure 3 is a sectional side view taken along the line III-III of Figure 2, and Figure 4 is a transverse sectional view thereof.

The cutting table shown comprises a lower box structure 2 the open top side of which is covered by a support grating 4 for one or more plate blanks (not shown) which are placed on the support grating in order to be cut by means of a torch tool 6 mounted in a movable manner on an overhad carrier structure (not shown), all in well known manner.

By means of partitions 8 and 10 the box 2 is divided into three transverse zones A,B, and C, the partitions 8 and 10 each being provided with a double inclined roof member 12 along their upper edges. Inside the box 2, centrally along the bottom thereof is provided an exhaust channel 14 extending through corresponding holes in- the partitions 8 and 10. The channel 14, at least at one end of the box 2, is connected to suitable fan means (not shown) for exhausting air from this channel. In each of the compartments A, B, and C the side walls of the channel 14 is provided with opposed circular holes 16 and 18 (see also Figure 2), and at one side of these respective holes is arranged a closing plate 20, these plates being mounted on a common shaft 22, which is extended to one side so as to constitute the piston rod of a cylinder 24, by means of which the plates 20 are movable between an open position as shown in the middle of Figure 2, in which they uncover the openings 16 and 18, and a closed position as shown in the right and left hand side of Figure 2 in which they close these openings.

Above the top side of the channel 14 each of the compartments A, B, and C are provided with a tray member 26 having upright side walls 28 spaced somewhat from the respective partitions 8 and 10 and from the respective end walls 30 and 32 of the box 2. Adjacent the top edge of each of these end walls 30 and 32 respectively there is mounted an inclined roof plate member 12' and all roof members 12 and 12' are arranged so as to cover the space between the tray sides 28 and the respective partitions 8 and 10 and the walls 30 and 32.

The torch 6 is mechanically connected with a sliding sho e 34 (Figure 3) which is operable to actuate anyone of a row of switches 36 corresponding to the torch 6 being located above any of the various exhaust compartments A, B or C, in such a manner that when a particular switch 36 is actuated in response to the torch being located above the zone B the cylinder 24 of this zone will be actuated so as to retract the closing plates 20 from the respective charr nel openings 16 and 18 and thus cause the exhaust channel 14 to be connected to the space defined between the partitions 8 and 10.

As most clearly shown in Figure 3 the space below the bottom of the tray 26 is the compart ment B will thereby be connected to the exhaust channel 14, and air will be sucked downwardly through the grate structure 4, generally towards the tray 26, as shown by arrows. Actually the air will be sucked down through the space between the tray sides 28 and the respective partitions 8 and 10, and practically all particulate contamination prod ucts from the cutting operation will be de posited on the bottom of the tray 26. The roof plates 12 covering the said space will ensure that none of these particles are falling or sucked down directly into the said spaces, and the roof plates 12 furthermore serve the purpose of bending the air flow in such a manner that the air from above is not sucked down into the said spaces in a concentrated manner, but all over the width of the tray 26. It is ensured hereby that the air is exhausted effectively from any of the exhaust zones A, B or C along the entire length thereof, even with the use of an exhaust source of limited capacity, and besides it is obtained that almost all particles of the contamination products are deposited in the tray 26. As shown in Figure 1, outside the end or ends of each of the trays 26 there may be arranged a closable opening 54 in the wall of the box 2, through which the respective trays may be emptied, e.g. by means of some suitable scraping tool or by removal of the entire tray through this opening.

The opening and closing of the channel holes 16 and 18 is controlled by means 34, 36 directly responsive to the actual location of the torch 6, whereby it is unnecessary to make use of special sensing means registering the occurrence of the cutting flame in each of the exhaust zones. The sliding shoe and switch arrangement 34, 36 may well be so adapted that suction is applied to both the zone in which the torch 6 is actually working and the neighbouring zones thereof,or the nearest neigh bouring zone thereof, whereby it is ensured that the neighbouring zone is connected to the exhaust system even prior to the torch tool entering this zone.

The exhaust system, of course, should comprise some kind of air cleaning equipment, but it will be appreciated that the contami nation products will generally be deposited in the trays 26, whereby the cleaning arrange ment may be designed in a rather simple manner. The exhaust duct 14 should not necessarily be located centrally along the bottom of the table, but such location con tributes to an even distribution of the air flow throughout the length of the transverse compartments. Of course, the width of the compartments should be adapted to the capacity of the exhaust system (or vice versa) in such a manner that the suction is effective also along the middle portion of the compart ments.

The invention is not necessarily limited to the use of selectively operable exhaust zones specifically as described with reference to the Figures since several trays may be placed side by side with some spacing between them, whereby these spaces, preferably covered by roof elements 12, may all be connected to the same exhaust chamber underneath the trays, or a series of the said spaces may be connected to an underlying selectively operable exhaust zone.

Immediately underneath the grating 4 there is mounted a network 38 made of round wires or rods serving to catch the cut plate pieces when these fall down from the plate being cut.

WHAT WE CLAIM IS: 1. A cutting machine including a table having a top grate structure for supporting plate material to be cut and an overhead torch system including a movable plasma torch to effect the cutting, exhaust means being pro vided underneath the top grate and comprising a series of parallel chamber portions defining respective exhaust zones, means for connecting the respective zones to means for exhausting air therefrom, wherein each exhaust zone as defined between opposed walls or partitions underneath the support grating comprises a tray member extending along the zone so as to have its bottom located at a level below the grating and spaced above the absolute bottom of the zone and so as to have upright side portions spaced somewhat from the respective walls or partitions, the space underneath the tray bottom communicating with said air exhausting means permanently or through selectively openable valve means.

2. A cutting machine according to claim 1, in which the spaces between the tray sides and the said walls or partitions are covered by inclined top plate means projecting from the top of said walls or partitions so as to be located spaced above the top edges of the tray sides.

3. A cutting machine according to claim 1 or claim 2, in which a closable opening is provided in the chamber wall adjacent one end of each tray.

4. A cutting machine according to claim 1, 2 or 3, in which the means for selectively connecting the respective exhaust zones with the exhausting means are controlled in direct response to presence of the torch above the respective zone.

5. A cutting machine having an exhaust system substantially as hereinbefore described with reference to the drawing.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (5)

**WARNING** start of CLMS field may overlap end of DESC **. neighbouring zones thereof,or the nearest neigh bouring zone thereof, whereby it is ensured that the neighbouring zone is connected to the exhaust system even prior to the torch tool entering this zone. The exhaust system, of course, should comprise some kind of air cleaning equipment, but it will be appreciated that the contami nation products will generally be deposited in the trays 26, whereby the cleaning arrange ment may be designed in a rather simple manner. The exhaust duct 14 should not necessarily be located centrally along the bottom of the table, but such location con tributes to an even distribution of the air flow throughout the length of the transverse compartments. Of course, the width of the compartments should be adapted to the capacity of the exhaust system (or vice versa) in such a manner that the suction is effective also along the middle portion of the compart ments. The invention is not necessarily limited to the use of selectively operable exhaust zones specifically as described with reference to the Figures since several trays may be placed side by side with some spacing between them, whereby these spaces, preferably covered by roof elements 12, may all be connected to the same exhaust chamber underneath the trays, or a series of the said spaces may be connected to an underlying selectively operable exhaust zone. Immediately underneath the grating 4 there is mounted a network 38 made of round wires or rods serving to catch the cut plate pieces when these fall down from the plate being cut. WHAT WE CLAIM IS:

1. A cutting machine including a table having a top grate structure for supporting plate material to be cut and an overhead torch system including a movable plasma torch to effect the cutting, exhaust means being pro vided underneath the top grate and comprising a series of parallel chamber portions defining respective exhaust zones, means for connecting the respective zones to means for exhausting air therefrom, wherein each exhaust zone as defined between opposed walls or partitions underneath the support grating comprises a tray member extending along the zone so as to have its bottom located at a level below the grating and spaced above the absolute bottom of the zone and so as to have upright side portions spaced somewhat from the respective walls or partitions, the space underneath the tray bottom communicating with said air exhausting means permanently or through selectively openable valve means.

2. A cutting machine according to claim 1, in which the spaces between the tray sides and the said walls or partitions are covered by inclined top plate means projecting from the top of said walls or partitions so as to be located spaced above the top edges of the tray sides.

3. A cutting machine according to claim 1 or claim 2, in which a closable opening is provided in the chamber wall adjacent one end of each tray.

4. A cutting machine according to claim 1, 2 or 3, in which the means for selectively connecting the respective exhaust zones with the exhausting means are controlled in direct response to presence of the torch above the respective zone.

5. A cutting machine having an exhaust system substantially as hereinbefore described with reference to the drawing.