Continuous reinforced plastics pipemaking machine

Claim 2

A machine according to claim 2, wherein axial reinforcing rovings are also laid on the extruded tube from bobbins on stationary bobbin carriers.

Claim 3

A machine according to claim 2, wherein the bobbins are in the form of cakes without cores or formers.

Claim 4

A machine according to claim 4, wherein the mandrel axis is vertical, or substantially so, enabling the carrier spindles for the cakes supplying the helical rovings to be likewise vertical or substantially so, and shifting of the cakes along a spindle takes place by gravity under the control of automatic latch means.

Claim 5

A machine according to claim 4, wherein the mandrel axis is horizontal, or substantially so, the carrier spindles for the cakes supplying the helical rovings being likewise horizontal, and powered cake-shifting means are provided in association with each spindle and rendered operative automatically upon occurrence of less than the full number of working cakes on that spindle, to shift the spare cake along the spindle into a working position and so make up the full working complement of cakes.

Claim 6

A machine according to claim 2, wherein said bobbin supply means comprises means to hold a supply of fresh cakes, in combination with transfer means operative to place a fresh cake from the supply on to any carrier spindle which has a cake missing.

Claim 7

A machine according to claim 7, wherein each rotating support applying the helical rovings bears a plurality of cake-carrying spindles parallel to and disposed around the mandrel axis at equal radial distances therefrom, the fresh cakes held by the fresh cake supply-holding means advance from time to time to arrive one after another at a position close to the path followed by said spindles as they rotate with said support, and the absence of a cake on any of the spindles initiates operation of the transfer means as that spindle arrives adjacent said position, the transfer means serving both to transfer a fresh cake to said spindle and simultaneously impart to that cake an angular acceleration about the mandrel axis whereby the transfer takes place without stopping of the rotation.

Claim 8

A machine according to claim 8, wherein the fresh cake supply-holding means comprise a chute down which the cakes advance under gravity.

Claim 9

A machine according to claim 8, wherein the transfer means comprise a cake holder that is rotatable with the support.

Claim 10

A machine according to claim 7, wherein the fresh cake supply-holding means comprise a cake container that is mounted for rotation about the mandrel axis at the same radius as the spindles on the support, and the transfer means comprise a pickup device whereby the cake container is angularly aCcelerated by any spindle which has a cake missing and becomes temporarily coupled to that spindle for transfer of a fresh cake thereto.

Claim 11

A machine according to claim 4, wherein said guide means for the rovings from a plurality of cakes along any one spindle are disposed in a row parallel to said spindle, in an arrangement such that the rovings automatically transfer from one guide to the next along the row as the cakes are shifted along the spindle.

Claim 12

A machine according to claim 12, and comprising a shifter bar operative upon shifting of the cakes along the spindle to engage the rovings and shift them along the row of guides.

Claim 13

A machine according to claim 4, and comprising means to bond the end of the roving of a spare cake to the roving of a working cake alongside it as shifting of the spare cake along the spindle into a working position occurs.

Claim 14

A machine according to claim 1, and comprising a continuous pressure-testing station through which the pipe is fed after it has been formed.

Claim 15

A machine according to claim 15, wherein the pressure-testing means comprises two interconnected pistons within the pipe and around which the pipe slides, which pistons define between them a chamber to which pressure fluid is introduced through the mandrel.

Claim 16

A machine according to claim 1, for making two or more pipes simultaneously either alongside one another or coaxial.

Claim 17

A machine according to claim 17, with provision for introducing material into at least one of the pipes through the respective mandrel as it is made.