US1587933A - Process and apparatus for the production of double-walled tubes - Google Patents

Description

June 8 1926. S 1,587,933

F. BARME PROCESS AND APPARATUS FOR THE PRODUCTION OF DOUBLE WALLBD TUBES Filed Sept. 15, 1924 Patented June 8, 1926.

PATIENT OFFICE.

FRIEDRICH BARME, OF ELBERFELD, GERMANY.

PROCESS ANJJAPPARATUS FOR THE PBODI TCTION OF DOUBLE-WALLED TUBES.

Application filed September 15, 1924, Serial No. 737,948, and in Germany August 27', 1923.

The invention relates to the pressing of double-walled tubes from lead or like suitable material, of the kind in which the inner tube is connected to the outer tube by conand driven through the hollow shaping space of the press mould Without interruption.

According to this invention the working material isfed to the hollowshaping spaces of the press mould from the outside inwardly. In contradistinction to the reverse process, the working material is in this way led together at all points for, the purpose of uniting it, its path being at the same time shortened. By this method the finished complete tube is improved because there can be no seams in the outer tube and the working material for the inner tube is securely closed together. At the same time also the press mould can be made simpler than for the reverse process.

a is an upright container, in which isthe plastic material (for instance molten lead) which can be pressed upwards out of the container by any suitable, for instance,hydraulic press apparatus, not shown. The

a ,press mould is situated in the head of this 40 container. The outer part consists of a press ring 71 seatedin a cover m of the container a. The inner part consists of a hollow member 0? with a cylindrical punch 72.

situated therein. The hollow member cl is secured by a' plug 0 into a socket b mountedin the container a. The hollow member 4 has longitudinal slots so that the upper part of the hollow mem er d consists of four tongues d, between which are the slots 7'.

In this way the press mould has hollow spaces at its outlet mouth which correspond to the material cross section of the doublewalled tube (Figure 1) to be pressed.

I f the pressing apparatus is put into operation, then the lastic working material (for instance lead is forced from outside into the various hollow spaces of the press mould. In the direction of the arrow 1 it passes inwards through the slots 7 and between the .tongues 03 and the punch h-to form the inner tube Z; in the direction of the arrow 2 it passes between the pressing ring 13 and the tongues dlto form the outer tube 2, and in the direction of the arrow 3 it rises upwards in the slots f to form the connecting strips 3. The double-walled tube is extended from the press mould, its length corresponding to the quantity of the material which is fed as desired into the container a.

As mentioned above, not only lead but other metals, or even other non-metallic plastic materials such as rubber, for instance, can also be pressed.

What I claim is .41. A press mold embodying a container, a hollow member therein having separated passa es and radial slots.

2. A press mold embodying a container, a hollow member therein having separated passages and radial slots, and annular tongues between the said slots.

3. The method herein described of making double-walled tubes from plastic material, consisting in feeding plastic material toward an axis and organizing the same into two concentric streams, forcing these streams through two circular concentric dies to form inner and outer pipes, permitting the streams -to work radially toward one another at spaced points to provide connecting webs between the inner and outer pipes, and leaving the spaces between the pipes and intermediate said webs unobstructed to form passa'geways for the circulation of fluid.

In testimony whereof I hereunto aflix my signature.

" FRIEDRICH BARME.

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