GB1598944A - Tube-forming machines - Google Patents

Description

(54) IMPROVEMENTS IN OR RELATING TO TUBE-FORMING MACHINES (71) We, SPIRO INVESTMENT, S.A., a Joint Stock Company organised and existing under the laws of Switzerland, of Industriestrasse, CH-3 178 Bösingen, Switzerland, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to machines for the production of metal tubing.

Lengths of so-called spiral lock-seam or helical lock-seam metal tubing, marketed for example under our Trade Marks SPIRO and SPIROVENT, are known to be produced in machines which form the tubing from metal strip which is pre-formed to provide shaped marginal parts which are then brought into mating relationship and clinched to form a helical lock-seam.

As described in, for example, British Patent No. 959,889 or in our co-pending Application No. 13004/78 Serial No. 1,598,943 filed on April 3, 1978, the marginal parts are brought into mating relationship in a rigid or relatively flexible forming head, and the seam is clinched on leaving the forming head.

These machines have given very satisfactory results, but they do involve the inconvenience of replacing the forming head when the machine is changed from the production of one tubing size to another. It is an object of the present invention to reduce or at least minimise this disadvantage.

According to the present invention there is provided a machine for the production of tubing by passing metal strip through pairs of forming rollers to form shaped marginal parts which are brought into mating engagement and clinched between clinching rollers to form a helical lock-seam, characterised in that said metal strip is guided into a helical path by passing from fixed guide means to the nip of an inner clinching roller and an outer clinching roller which is adjustable round the periphery of the inner clinching roller to effect bending of the strip to the degree required to follow the desired helical path.

Suitably, the axial length of said inner clinching roller and said outer clinching roller is at least equal to the breadth of said preformed strip.

An embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings in which: Figure 1 is a fragmentary side view of a machine for the production of flexible tubing from metal strip; Figure 2 is a plan view corresponding to Figure 1 but not including the metal strip; and, Figure 3 is a detail section on the line III--III of Figure 1.

Referring to the drawings, the machine is provided with a supply spool 10 carrying a coil of aluminium strip 11 from which the lengths of tubing are to be formed. The machine comprises a series of five pairs of driven forming rollers 12 which receive the strip 11 via an oil bath 13, the strip passing over idler de-coiling rollers 14 and then over a driven feed roller 15 before passing between the pairs of forming rollers 12.

The forming rollers operate to produce axial corrugations in the strip and also to pre-form the marginal parts of strip for the subsequent formation of a seam.

On leaving the forming rollers 12, the pre-formed strip passes between a pair of small idler rollers 16 and between a pair of stationary guide plates 17 which extend to a forming station at 18. On reaching the forming station, the strip passes into a nip formed by an elongated inner clinching roller 19 and an elongated outer clinching roller 20, which so bends the strip that it proceeds through a helical path indicated at P to return to the rollers 19 and 20 which clinch the mating marginal parts to form a helical lock-seam of the form described in Patent No. 959,889.

The drive to the various rollers is derived from a hydraulic motor 21 which rotates a horizontal drive shaft extending from gear box 22 through a compartment 23 which contains take-off drives to the upper and lower rollers 12. The shaft then extends under a cover (not shown) through coupling 24, extension piece 25, and coupling 26, to an end box 27 which houses a worm drive shaft 28 to a worm pinion 29 mounted at one end of a short transverse shaft 30. The shaft 30 extends through a stepped tubular extension 31 of the box and carries the inner clinching roller 19 at its other end.

The outer idler clinching roller 20 rotates on a horizontal shaft 32 carried by a split bearing member 33 which is clamped around the tubular extension 31 by means of a clamping bolt 34. On loosening the bolt, the member 33 can be tamed on the extension 31 to move the roller 20 round the roller 19, and so adjust the diameter D of the tubing to be produced. A pin 35 movable in a recess 36 in the extension 31 is provided to limit the movement of the member 33 on engaging the ends of the recess. The shaft 32 has an eccentric outer end 32A which carries the roller 20, and this -end is movable to adjust the radial position of roller 20 which is held by a quick release clamp 37.

It has been found that, particularly in the production of flexible tubing, the positioning of the rollers 19 and 20 in relation to the outlet end of the gap between the virtually rigid guide plates 17 is sufficient to guide the strip satisfactorily without the provision of a helical forming head. It may, however, be desirable to feed the leading end of each length of curved strip manually or mechanically into the nip between rollers 19 and 20 in correct mating alignment with the subsequent section. Furthermore, a change from one tubing diameter to another simply involves a shift of the axis of the outer roller 20, without the time-consuming inconvenience of replacing a forming head, and of course the tubing diameters can be infinitely varied between minimum and maximum limits.

It will also be noted that the operative parts described above are mounted on a chassis 38 which has the same form as the chassis in our earlier machines which incorporated upper and lower drive rollers rotating on axes at 39 and 40. Thus, the operative upper parts of our earlier machine which is normally used for the production of more rigid tubing and ducting, can be replaced by the chassis 38 carrying the various operative parts of the unit and which results in the economy of having a control console indicated at 41 which can be used in the production of the more rigid steel tubing or of the more flexible aluminium tubing.

WHAT WE CLAIM IS:- 1. A machine for the production of tubing by passing metal strip through pairs of forming rollers to form shaped marginal parts which are brought into mating engagement and clinched between clinching rollers to form a helical lock-seam, characterised in that said metal strip is guided into a helical path by passing from fixed guide means to the nip of an inner clinching roller and an outer clinching roller which is adjustable round the periphery of the inner clinching roller to effect bending of the strip to the degree required to follow the desired helical path.

2. A machine as claimed in Claim 1, in which the axial length of said inner clinching roller and said outer clinching roller is at least equal to the breadth of said pre-formed strip.

3. A machine as claimed in Claim 1 or Claim 2, in which said inner clinching roller is mounted at the end of a driven shaft which is journalled in a tubular bearing member and said outer clinching roller is mounted at the end of a shaft which is carried by a split bearing member which is releasably clamped around said tubular bearing member.

4. A machine as claimed in Claim 3, in which said inner clinching roller is driven and said outer clinching roller is an idler roller.

5. A machine as claimed in Claim 3 or Claim 4, in which said outer clinching roller is mounted eccentrically on its shaft to provide for radial adjustment of the position of the outer clinching roller in relation to the inner clinching roller.

6. A machine as claimed in any preceding Claim, in which said forming rollers and drive means for the forming rollers are mounted on a chassis which is removable from the body of the machine, said body comprising a base and a control console adapted to receive a chasis carrying alternative forming rollers and drive means.

7. A machine for the production of metal tubing substantially as hereinbefore described with reference to the accompanying drawings.

8. Tubing whenever produced in a machine as claimed in any preceding Claim.

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

Claims (8)

**WARNING** start of CLMS field may overlap end of DESC **. take-off drives to the upper and lower rollers 12. The shaft then extends under a cover (not shown) through coupling 24, extension piece 25, and coupling 26, to an end box 27 which houses a worm drive shaft 28 to a worm pinion 29 mounted at one end of a short transverse shaft 30. The shaft 30 extends through a stepped tubular extension 31 of the box and carries the inner clinching roller 19 at its other end. The outer idler clinching roller 20 rotates on a horizontal shaft 32 carried by a split bearing member 33 which is clamped around the tubular extension 31 by means of a clamping bolt 34. On loosening the bolt, the member 33 can be tamed on the extension 31 to move the roller 20 round the roller 19, and so adjust the diameter D of the tubing to be produced. A pin 35 movable in a recess 36 in the extension 31 is provided to limit the movement of the member 33 on engaging the ends of the recess. The shaft 32 has an eccentric outer end 32A which carries the roller 20, and this -end is movable to adjust the radial position of roller 20 which is held by a quick release clamp 37. It has been found that, particularly in the production of flexible tubing, the positioning of the rollers 19 and 20 in relation to the outlet end of the gap between the virtually rigid guide plates 17 is sufficient to guide the strip satisfactorily without the provision of a helical forming head. It may, however, be desirable to feed the leading end of each length of curved strip manually or mechanically into the nip between rollers 19 and 20 in correct mating alignment with the subsequent section. Furthermore, a change from one tubing diameter to another simply involves a shift of the axis of the outer roller 20, without the time-consuming inconvenience of replacing a forming head, and of course the tubing diameters can be infinitely varied between minimum and maximum limits. It will also be noted that the operative parts described above are mounted on a chassis 38 which has the same form as the chassis in our earlier machines which incorporated upper and lower drive rollers rotating on axes at 39 and 40. Thus, the operative upper parts of our earlier machine which is normally used for the production of more rigid tubing and ducting, can be replaced by the chassis 38 carrying the various operative parts of the unit and which results in the economy of having a control console indicated at 41 which can be used in the production of the more rigid steel tubing or of the more flexible aluminium tubing. WHAT WE CLAIM IS:-

1. A machine for the production of tubing by passing metal strip through pairs of forming rollers to form shaped marginal parts which are brought into mating engagement and clinched between clinching rollers to form a helical lock-seam, characterised in that said metal strip is guided into a helical path by passing from fixed guide means to the nip of an inner clinching roller and an outer clinching roller which is adjustable round the periphery of the inner clinching roller to effect bending of the strip to the degree required to follow the desired helical path.

2. A machine as claimed in Claim 1, in which the axial length of said inner clinching roller and said outer clinching roller is at least equal to the breadth of said pre-formed strip.

3. A machine as claimed in Claim 1 or Claim 2, in which said inner clinching roller is mounted at the end of a driven shaft which is journalled in a tubular bearing member and said outer clinching roller is mounted at the end of a shaft which is carried by a split bearing member which is releasably clamped around said tubular bearing member.

4. A machine as claimed in Claim 3, in which said inner clinching roller is driven and said outer clinching roller is an idler roller.

5. A machine as claimed in Claim 3 or Claim 4, in which said outer clinching roller is mounted eccentrically on its shaft to provide for radial adjustment of the position of the outer clinching roller in relation to the inner clinching roller.

6. A machine as claimed in any preceding Claim, in which said forming rollers and drive means for the forming rollers are mounted on a chassis which is removable from the body of the machine, said body comprising a base and a control console adapted to receive a chasis carrying alternative forming rollers and drive means.

7. A machine for the production of metal tubing substantially as hereinbefore described with reference to the accompanying drawings.

8. Tubing whenever produced in a machine as claimed in any preceding Claim.