US1619362A

US1619362A - Withdrawing cores from molded conduits

Info

Publication number: US1619362A
Application number: US738151A
Authority: US
Inventors: Thomas E Murray
Original assignee: Individual
Current assignee: Individual
Priority date: 1924-09-17
Filing date: 1924-09-17
Publication date: 1927-03-01
Anticipated expiration: 1944-03-01

Description

1 l a March 927 T. E. MURRAY WITHDRAWING CORES FROM MOLDED CONDUITS Filed Sept. 17', 1924 avwe'ntom 7710/17/15 5 Mar/"(1y Patented Mar. 1, 192 7.

UNITED STATES PATENT OFFICE.

THQMAS E. MURRAY, OF BROOKLYN, NEW YO RK. q

wrrnnimwme corms FROM MOLDED CONDUITS.

Application filed September 17, 1924. SerialNo. 738,151.

In an application of Thomas E. Murray,

No. 670,423, now Patent 1,556,869, dated composition that when pulled longitudinally it will contract transversely to break its adhesion to the surrounding material and permit its withdrawal. Such cores are generally made of high grade rubber composition to secure the necessary resiliency. When the conduit is of considerable length or is curved longitudinally the' withdrawal of the core requires a very strong pull, and a point is reached at which high gradematerial wil not stand the strain, but will break.

My present invention provides a way of lessening the strain required to pull such cores out of the molded material; thus permitting the use of longer cores or, for a given 'ength, of cores of greater resiliency even, though this means reduced strength. The accompanying drawings illustrate an embodiment of the invention. Fig. 1 illustrates in longitudinal section the operation of pulling a flexible core out of the molded conduit. Fig. 2 illustrates the same in crosssection on the line 22. Fig. 3 illustrates a modification in section.-

The tubular soft rubber core 1 has'been used to form a conduit 2 in a body of plastic material 3. The conduit is shown with a curvedportion t by way of example. The invention, however, is useful on straight lengths as well as on curves. The projecting end of the core is pulled in the direction of thearrow 5. If the length be not too great or the friction due to the 'curvein the conduit be 'not. too great, the core can be pulled out without putting a strain on it which is beyond the strength of the material of which it is composed. Such a pull will diminish the cross-section and break the ad'- hesion of the rubber to the surrounding concrete progressively backward along the length-of the conduit. and permit the withdrawal of the core. I

But where the strainrequired is beyond the strength of the material a-special means is used or breaking the adhesion between the tube and the surrounding wall at least sufiiciently .to permit the withdrawal of the core under a tension less than its breaking strength. The adhesion may readily be broken to a considerable extent by thrusting a nozzle 6 between the core and the sur-' rounding wall at the exposed end of the. conduit and forcing air or water or other lubr1cant into the space between the core and the surrounding wall. The nozzle may be made of iron pipe or any other suitable material. will force its way between the core and the surrounding wall backward along the length of the core escaping into the rear end of the conduit as indicated by the arrows 7 .The mere loosening of the core in this way will sometimes be suflicient, theoperation being The air or other fluid introduced completed before the core is pulled. But

pressing the latter in the direction of its withdrawal.

According to Fig. the nozzle .6 is con-- nected at its rear end to two branch pipes 7 and 8, theformer for air and the latter for generally it will be preferable to continue water, with a cock 9- for cutting oif the water.

Instead of water, oil or other liquid lubricant may be used.

With this apparatus, according to the circumstances of the case, air, may be used alone to release the core from the surrounding wall, or water (or other liquid) may be used alone, or the two may be supplied at the same time. I have found it particularl advantageous to first forcea liquid through the nozzle and th follow this with Although I have described with great particularity' of detail a certain embodiment of my invention, yet it is not to be understood therefromthat the invention is restricted 'to the particular embodiment of the invention disclosed. Various modifications there- What I claim is material by means .of a flexible core, the

method of withdrawal which consists in.

forcing a lubricating fluid into the space be- 1. In the molding of conduits in plastic tween the core and the surrounding-wall so as to flex the core to break the adhesion While pulling the core longitudinally to withdraw it from the conduit. 7

2. In the molding of conduits in plastic material by the use of a flexible tubular highly resilient core, the method of Withdrawing the core which consists in the foreing of a fluid between the outside of the core and the surrounding wall so as to break their adhesion to each other and simultaneously pulling the end of the core so as to cause it to contract in cross-section and thus augment the breaking of its adhesion to the surrounding Wall. a

3. In the molding of conduits in plastic material by means of a flexible core, the method of withdrawal which consists in the forcing of a liquid and air into the space between the core and the surrounding Wall.

In Witness whereof, I have hereunto signed my name.

THOMAS E; MURRAY.