GB2387134A - A method of manufacturing metal gutters - Google Patents

Abstract

A metal gutter (10a; 10b; 10a'; 10b') is formed from a spin-cast, hollow, cylindrical pipe (10'; 10, ), by parting the pipe along two lines (11, 12) that are mutually circumferentially spaced on the pipe (10'; 10, 110, ) and extend parallel to its longitudinal axis. The pipe (10'; 10, ) is parted using a plasma cutter head to cut the pipe along the lines (11, 12). A programmable support jig supports and positions the pipe (10'; 10, ) during the cutting operations.

Description

r METHOD OF MANUFACTURING METAL GUTTERS

This invention relates to a method of manufacturing metal gutters. The invention also relates to an apparatus for forming such gutters; and to gutters formed using the method and apparatus of the invention.

In general there are two kinds of gutter in widespread use. These are so-

called "plastic" gutters that are formed, in discrete lengths, from any of a range of plastics materials; and metal gutters that typically are formed from .. iron or aluminum.

Plastic gutters have become very popular in recent years, for the following reasons: À they are cheap À they are light in weight and hence easy to store, transport, install, cut to length and adjust; À they are regarded as "maintenance-free", primarily because they do not require regular painting; À they can be produced in a variety of self-coloured finishes; and À they are available in a range of profiles.

Despite these apparent advantages, there are many installations in which plastic gutters are unsuitable.

For example, many older buildings, that constitute a substantial part of the housing and public building stock of the UK, are protected in a variety of

regulatory ways against visible adulteration. Plastic gutters are rarely permissible in such locations.

Moreover, plastic gutters require more maintenance than is popularly perceived. This is partly because plastic gutters tend to sag over time and require adjustment to prevent them from leaking, overflowing or looking unsightly.

Moreover the lightness of plastic gutters renders them susceptible to damage caused ea. by storms.

Metal gutters are commonly used in cases, such as those outlined above, in which plastic gutters are unsuitable.

Traditionally the method of forming metal gutters has been by die pressing or sand casting of iron to form individual gutter lengths.

These techniques require a substantial excess of iron. In the case of die pressing this is because of the need to overpress the metal. Consequently the yield of the die pressing technique is approximately 50%; and that of sand casting about 70%.

Furthermore the die pressing technique results in the production of noticeable amounts of flash at the edges of the gutter profile. The gutters require de-flashing as a result. This step requires clamping of each pressed gutter in a straightening jig until its temperature drops from the as-pressed temperature, of about 700 C, to about 400 C. At this temperature the shape of the gutter is sufficiently set to allow deflashing ea. by virtue of an operator using a grinding tool.

The need to de-flash the gutters results in a scrap rate of about 10%.

Although the scrap can be re-cycled, the existing process nonetheless is time-consuming and expensive to operate. Typically in the UK a gutter die pressing line requires the equivalent of 4/: men to operate. Such a line produces approximately 40 gutters per hour, at a cost (at present iron prices) of about ú1,100 / tonne.

Recently, cheaper metal gutters have entered the UK market. Typically they arrive from countries where one or more of the following situations prevail: À iron prices are artificially low, ea. because of government subsidies; À health and safety standards are poor or non-existent; and À wages are very low.

According to a first aspect of the invention, there is provided a method of manufacturing metal gutters comprising the step of cutting at least one hollow, elongate, cylindrical metal pipe lengthwise along at least two circumferentially spaced lines so as to form two open sided, elongate, hollow, part-cylindrical troughs.

The pipe, from which the gutters are formed, may be produced by a more efficient method such as that specified hereinbelow, than the prior art die

pressing method.

In one embodiment of the invention the lines are circumferentially spaced from one another by approximately 180 . This version of the method of the invention results in the production of two "half round" gutters from each

cylindrical pipe.

In an alternative embodiment of the method the pipe is cut lengthwise along three circumferentially spaced lines a first of which is spaced equally from the second and third, that are spaced from one another by a lesser spacing then that from which they are each spaced from the first line. This version of the method results in the production of two gutters, from each cylindrical pipe, that in cross section are each an arc of less than 180 in the angular direction. Preferably the lines, along which the pipes are cut, are mutually parallel and substantially straight. However if desired it is possible to cut the pipe along mutually divergent lines and/or lines that are non-rectilinear.

Conveniently the method includes the sub-step of using one or more plasma cutter heads to cut the pipe along the said lines. This type of cutter produces cut lines of high quality, that resemble machine cut (ea. milled) lines. As a result the gutters are attractive and unlikely to cut a user.

The preferred method according to the invention includes the further sub-

step of moving a said pipe and a said plasma cutter head relative to one another generally parallel to the lengthwise dimension of the pipe during cutting of the pipe along each said line. More specifically the method includes sequential cutting of the pipe along the respective lines, the method further including the step of rotating the pipe and the plasma cutter head one relative to the other between the cuts of the sequence.

These method steps advantageously lend the method of the invention to implementation by a programmable apparatus that is programmed to effect a series of cuts and rotations.

In a particularly preferred embodiment of the method, the pipe is formed by spin casting of molten metal, especially so-called "grey iron", before cutting of the pipe commences.

Even more preferably the method of the invention includes the simultaneous cutting of a pair of the pipes each along a said lengthwise extending line.

In a further preferred aspect of the method of the invention the pair of pipes are part of a batch of pipes consisting of a number of said pairs, the respective pairs of each batch being cut alternately until completion of the method in respect of all pairs of pipe of the batch. Advantageously the method includes the use of a pair of plasma cutter heads to effect simultaneous cutting of the or each said pair of pipes.

The foregoing features of the method greatly improve the efficiency of gutter manufacture. Using the method of the invention it is possible to produce metal gutters at a rate of about 140 per hour, using the equivalent of three men. The cost of such production is about ú700 / tonne. The yield is approximately 95% and the scrap rate is 3%. The straightening and de-

flashing steps needed in the prior art methods are unnecessary in the method

of the invention.

According to a second aspect of the invention there is provided apparatus for carrying out a method according to the invention as hereinbefore defined, the apparatus comprising a moveable bed for supporting one or more metal pipes with their longitudinal axes generally parallel; and one or more plasma cutter heads supported for movement relative to the pipes, the bed being moveable perpendicular to the said longitudinal axes; and the or each plasma cutter head being moveable parallel to the said longitudinal axes.

Preferably the or each pipe is rotatably supported on the bed; and preferably the apparatus includes one or more motors for moving the bed and the or each plasma cutter head; and for causing rotation of one or more said pipes on the said bed.

Conveniently the or each said motor is controlled by a programmable device that is programmed to produce a predetermined sequence of cuts in each pipe.

According to a third aspect of the invention there is provided a metal gutter formed from an elongate, hollow pipe parted along at least two circumferentially spaced lines extending generally parallel to the longitudinal axis of the pipe. In a further, optional embodiment of the gutter of the invention the pipe is parted along three circumferentially spaced lines extending generally parallel to the longitudinal axis of the pipe.

Optionally the lines are plasma cut; and/or the gutter includes a lip at or adjacent at least one end thereof.

The lip assists in jointing adjacent gutter lengths together by acting as a socket-like member for receiving the free end of an adjacent gutter length.

Preferably the pipe from which the gutter is cut is a spin cast pipe.

There now follows a description of preferred embodiments of the invention,

by way of non-limiting example' with reference being made to the accompanying drawings in which: Figure 1 is a schematic representation of one type of spin-cast, cylindrical water pipe, showing one pattern of cuts according to the invention; Figure 2 is a schematic view of another pipe, showing a different

arrangement of cut lines; and Figures 3A-3E represent a sequence of cuts and movements needed to process a batch of two pairs of pipes to produce eight gutter lengths.

Referring to Figure 1 of the drawings one method, according to the invention, of forming gutters in its simplest form includes cutting an elongate, hollow, cylindrical pipe 10 lengthwise along two circumferentially spaced lines 11, 12 represented by dotted lines in Figure 1.

Such cutting of the pipe 10 results in the production of two open sided, elongate, hollow, part-cylindrical troughs lea, lOb that are each suitable as lengths of gutter.

As. In the Figure 1 embodiment the lines 11, 12 are circumferentially spaced from one another by an angular measurement of 180 . The lines 1 1, 12 are rectilinear and mutually parallel, whereby each of the resulting troughs lOa, 1 Ob is of half-round cross section along its length.

Figure 2 shows a variant on the arrangement of Figure 1.

In Figure 2 the pipe 10' is similar to the Figure 1 pipe 10, being a hollow cylinder of constant cross section over almost all its length.

At one end pipe 10' flares outwardly to define an open, annular bell mouth 13 of larger diameter than the remainder of the pipe 10'.

Pipe 10' is according to the method of the invention parted along three lines 11, 1 2 and 1 4 represented in the figure by dotted lines. Lines 1 1, 1 2 and 1 4 are mutually parallel, and rectilinear.

first line 11 of the three is circumferentially equally spaced from the

second and third lines 12, 14.

Lines 12 and 14 are spaced from one another by a lesser circumferential distance than that from which they are each spaced from line 11.

Consequently the cross sections of the troughs lOa' and 1 Ob' resulting from cutting of the pipe 10' as signiiE;ed in Figure 2 are arcuate, and of less than 180 circumferential dimension.

A further variant on the Figure 2 arrangement is to part the pipe 10' along three lines arranged asymmetrically so as to produce two troughs that are of mutually different cross sections although commercially this may be undesirable. The bell mouth 13 at one end of pipe 10' defines at one end of each of the finished troughs lea' and lOb' a so-called gutter lip. This acts as part of a socket in which in use is receivable the nonflared end of a further length of gutter to define a gutter joint.

The gutter joint may be finished in any of a number of per se known ways including but not limited to screwing together of the adjoining gutter lengths; and/or the use of sealing compounds in the joint.

The Figure 1 pipe may be modified within the scope of the invention to include the flared bell mouth 13 visible in Figure 2, whereby the troughs 1 Oa, 1 Ob would also each include a respective gutter lip at one end.

The preferred method of cutting the pipes 10 and 10' involves moving the pipe 10 or 10' and one or more plasma cutter heads relative to one another during operation of the cutter head to cut the lines as described herein.

The relative movement between the pipe and the cutter heads includes plural movements generally parallel to the lengthwise dimension of the respective pipe; and rotation of the pipe and the cutter head relative to one another, intermediate at least two such lengthwise movements.

In practice the pipes 10 or 10' are cut in batches of two pairs (ie. batches of four pipes each) so as to produce eight gutters at a time.

The preferred production sequence for the gutters, and the preferred production apparatus, are shown schematically in plan view in Figures 3A-

3E. Figures 3A-3E show the steps in the production of four pairs of gutters 10a, 10b as shown in Figure 1. The sequence of steps requires only minor modification to produce the gutters 10a', lob' of Figure 2.

In Figures 3A and 3B a series of four hollow, cylindrical pipes 10, 110, 210, 310 are fed via an horizontally extending conveyor 17 from a pipe production apparatus (not shown) onto a moveable, horizontal bed 16 that at the outset of the procedure lies adjacent part of conveyor 17.

In the preferred embodiment the pipe production apparatus is a spin casting mould. This apparatus has the advantage of producing pipes that are uniformly cylindrical and are self-supporting after a comparatively short period of cooling in an upright position.

Preferably the pipes 10, 1 10, 210, 310 are cast from so-called grey iron.

Other pipe production methods are possible within the scope of the invention. In the preferred embodiment of the invention the pipes 10, 110, 210, 310 are sequentially fed lengthwise along conveyor 17 as signified by arrow A.

Adjacent bed 16 conveyor 17 is open along one side thereby permitting ejection of the pipes one at a time onto the bed 16. Such ejection may occur, as signified by arrows B. by means of solenoid actuated pushers; further conveyor elements; a gated gravity feed or any of a range of other mechanisms. The precise pipe ejection mechanism is omitted from Figures 3 for clarity.

The result of ejection of the pipes 10, 110, 210, 310 is that they lie side by side on the upper surface of bed 16, as shown in Figure 3B, with their longitudinal axes parallel to one another.

Along one side edge 16a bed 16 has secured thereto a row of rotary motors 18, 19, 21 22, each presenting a mandrel 23 that is secured to its output shaft and overlies the upper surface of bed 16.

Each mandrel 23 is expandable and contractable or otherwise capable of gripping the exterior of a pipe 10, 110, 210, 310. Following ejection of the pipes 10, 110, 210, 310 to lie as shown in Figure 3B the respective pipe ends are each insertable into an adjacent mandrel 23 and clamped thereby ea. under control of a conko1 system, by releasing of a latch or by any equivalent means.

As a result each mandrel 23 secures one of the pipes 10, 110, 210, 310 against unintended movement, until operation of the motors 18, 19, 21, 22 as described below.

As signified by dotted lines in Figure 3A-3E, a gantry 24 extends horizontally above bed 16 from one side thereof to the other. A pair of plasma cutter heads 26, 27 are suspended from the underside of the gantry 24 and are each slideably moveable, ea. in parallel tracks, from one side of

the gantry 24 to the other, parallel to the lengthwise dimension of the pipes 10, 110,210, 310.

The gantry 24 includes one or more motors and associated drive train components for driving the plasma cutter heads in both directions along the gantry 24. Such components are not visible in the drawings but are of kinds that will readily occur to those of ordinary skill in the relevant art.

Also associated with the plasma cutter heads 26, 27 are flexible pipes and cables (not visible in the drawings but known per se) for supplying the plasma gas and arc current to the cutter heads.

Oxygen is a suitable plasma gas for cutting iron, although other gases are possible. As signified by arrows C in Figure 3B, the cutter heads are initially moved from one side of gantry 24 to the other while operating to cut on each of pipes 10 and 110 along first lines 11. Such cuts are visible in Figure 3C.

With the cutter heads 26 and 27 located as shown in Figure 3C the bed 16 is then moved horizontally as indicated by arrows D, so that gantry 24 overlies pipes 210, 310.

The plasma cutter heads 26, 27 then return across gantry 24 to cut lines 11 in pipes 210, 310.

Simultaneously with the cutting of the lines 11 in the pipes 210, 310 the motors 18, 19 operate to rotate each of the pipes 10, 110 through 180 so that the cuts 11 lie on the undersides of the pipes. The bed 16 may include in its upper surface rollers or bearings that facilitate the rotation of the pipes.

l It is then possible to return the bed 16 to its initial position as signified by arrows E in Figure 3D. Subsequently the plasma cutters 26, 27 may be driven back across the gantry 24 to cut the further lines 12 in the pipes 10, llO as shown in Figure 3E. This separates the pipes 1O, 110 into four gutters. During this action the motors 21, 22 rotate the pipes 210, 310 through 180 each on the rollers or bearings (if present), so that the cuts 11 therein lie on the undersides of the pipes adjacent the bed 16.

The bed 16 may then be returned to its position as indicated in Figure 3D for cutting of the lines 12 in the pipes 210, 310 that also then separate into four gutters.

The eight resulting gutters may then be removed from bed 16 manually or by any of a range of mechanised means.

The above-described process may then re-commence in respect of a further batch of two pairs of pipes.

In order to cut the pipes as shown in Figure 2 it is necessary only for the plasma cutter heads 26, 27 to make an extra pass over each pair of pipes.

When as in the preferred embodiment the apparatus of the invention is configured as or is operatively connected to a programmable device, this is straightforwardly achieved.

It is also possible within the scope of the invention to cut the various lines 1 1, 12 and 14 as desired with non-rectilinear edges. This is also particularly suited to programming of a programmable device.

Claims (24)

1. A method of manufacturing metal gutters comprising the step of cutting at least one hollow, elongate, cylindrical metal pipe lengthwise along at least two circumferentially spaced lines so as to form two open sided, elongate, hollow, part-cylindrical troughs.

2. A method according to Claim 1 wherein the lines are

circumferentially spaced from one another by approximately 180 .

3. A method according to Claim 1 including the step of cutting the pipe lengthwise along three circumferentially spaced lines a first of which is spaced equally from the second and third, that are spaced from one another by a lesser spacing then that from which they are each spaced from the first line.

4. A method according to any of Claims 1 to 3 wherein the said lines are mutually parallel and are each substantially straight.

5. A method according to any preceding claim including a sub-step of using one or more plasma cutter heads to cut the pipe along the said lines.

6. A method according to Claim 5 including the further sub-step of moving a said pipe and a said plasma cutter head relative to one another generally parallel to the lengthwise dimension of the pipe during cutting of the pipe along each said line.

7. A method according to Claim 6 including sequential cutting of the pipe along the respective lines, the method further including the step of rotating the pipe and the plasma cutter head one relative to the other between the cuts of the sequence.

8. A method according to any preceding claim including the step of forming the pipe by spin casting molten metal, before cutting of the pipe commences.

9. A method according to Claim 8 wherein the pipe is spin cast from grey iron.

10. A method according to any preceding claim including the simultaneous cutting of a pair of the said pipes each along a said lengthwise extending line.

1 1. A method according to Claim 10 wherein the pair of pipes are part of a batch of pipes consisting of a number of said pairs, the respective pairs of each batch being cut alternately until completion of the method in respect of all pairs of pipe of the batch.

12. A method according to Claim 10 or Claim 11 including the use of a pair of plasma cutter heads to effect simultaneous cutting of the or each said pair of pipes.

13. Apparatus for carrying out a method according to any preceding claim, comprising a moveable bed for supporting one or more metal pipes with their longitudinal axes generally parallel; and one or more plasma cutter heads supported for movement relative to the pipes, the bed being moveable perpendicular to the said longitudinal axes; and the or each plasma cutter head being moveable parallel to the said longitudinal axes or vice versa.

14. Apparatus according to Claim 13 wherein the or each pipe is rotatably supported on the bed.

15. Apparatus according to Claim 13 and Claim 14 including one or more motors for moving the bed and the or each plasma cutter head; and for causing rotation of one or more said pipes on the said bed.

16. Apparatus according to Claim 15 wherein the or each said motor is controlled by a programmable device that is programmed to produce a predetermined sequence of cuts in each pipe.

17. A metal gutter formed from an elongate, hollow pipe parted along at least two circumferentially spaced lines extending generally parallel to the longitudinal axis of the pipe.

18. A gutter according to Claim 17 when formed from a pipe parted along three circumferentially spaced lines extending generally parallel to the longitudinal axis of the pipe.

19. A gutter according to Claim 18 or Claim 19 wherein the lines are plasma cut.

20. A gutter according to any of Claims 17 to 19 including a lip at or adjacent at least one end thereof.

21. A gutter according to any of Claims 17 to 20, and formed from a spin cast pipe.

22. A method generally as herein described, with reference to and/or as illustrated in the accompanying drawings.

23. Apparatus generally as herein described with reference to and/or as illustrated in the accompanying drawings.

24. A metal gutter generally as herein described with reference to and/or as illustrated in the accompanying drawings.