US442958A - Thomas curran - Google Patents

Description

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T. GURRAN. MOLD 'FOR MAKING yPLA'STER SLABS.

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UNITED STATES PATENT OEEicE,

THOMAS CURRAN, OF NEV YORK, N. Y.

MOLD FOR MAKlNG PLASTER SLABS.

SPECIFICATION' forming part of Letters Patent No. 442,958, dated December 16, 1890. Appncaim filed April 8,1890. sereine. 347,077. (roman.)

To all whom' it may concern:

Be it known that I, THOMAS CURRAN, a citizen of the United States, residing in the city, county, and State of New York, have invented certain new and useful Improvements in Molds for Making Plaster' Slabs, of which the following is a specification.

The invention relates to an improved molding strip or sheet for forming or molding plastic material, especially that which is adapted to be attached to the interior Walls or ceilings of houses, so that when so attached they will vform a means for the reception of a brown coat and a coat of lhard finish, which are generally applied and employed for such purposes.

As stated above, my invention in the pres ent instance relates to the construction of the mold, and it relates particularly toimprove ments on the mold shown, described, and claimed by me in my previous application filed in the United States Patent Office on the 11th day of March, 1890, Serial No. 343,474.

In my previous application I provided a rigid rectangular frame and a flexible molding piece or sheet havin g longitudinal Wooden or other strips inserted in the face thereof, and so arranged as to protrude in relief above the normal surface of the said flexible molding-sheet, whereby when it was applied to a plastic compound contained Within the rectangular frame aforesaid, the longitudinal strips would embed themselves in the plaster and would form corresponding or complementary grooves therein which were to be utilized for the purpose of retaining the furn ther and superimposed brown coat and hard finish Well known in the plasterers art. My present invention is designed to combine the rectangular frame with the flexible molding-sheet and to render the Whole structure homogeneous as Well as iiexible, and to this end I construct a mold with its surround ing frame integrally and of india-rubber and provide the interior raised portions of ribs similar to those described and claimed in my previous application aforesaid.

Referring to the accompanying drawings,

which form apart of this specification, Figure I represents a cross-section of my improved combined fiexible molding sheet and frame, and Fig. II is a plan view thereof.

C represents the longitudinal ribs or raised strips, which extend between and connect the ends B B.

D representsthe longitudinal grooves or depressions in the mold, which are parallel with and intermediate to the longitudinal ribs C. These grooves are provided with corrugation d, as shown in Fig. I, so that When the plaster slab is removed from the mold the outer faces of the slab will have an additional means for supporting the superimposed mortar.

In Fig. I, I show the mold in its operative position, the plasterE being contained therein. When the plaster has been inserted in the mold, as shown, it is smoothed over at the surface so that it will be even With the frame A A B B. When it has hardened sufficiently the frame and its contents are turned over.. The frame is then removed from the slab by lifting it at one of its sides A. The mold is so made that by virtue of its elasticity it can be readily drawn off from the slab in the manner described. i

Another feature of my invention, and which is set forth in my previous application herein referred to, but is applicable also to this, is the formation of the sides or edges of the longitudinal ribs of the flexible molding-strip. These sides or edges are preferably made substantially as shown in Fig. I of the accompanying drawings, one of the edges, as shown at F, being considerably inclined after the manner of a dovetail joint, so that when the plaster cast formed thereby is attached to the Wall or ceiling the outsetting edge G onthe slab formed by the aforesaid projection F will retain the mortar and prevent it from dropping. In other Words, it constitutes a permanent lock for the superimposed plaster or mortar. The opposite sides of the ribs C are made nearly straight, as shown at H, so that when the mold is Withdrawn it Will encounter no opposition. The corrugations d in the grooves of the mold Will create corresponding elevations and depressions on the IOS most exposed part of the plaster slab, thereby 2. A mold for forming` plastic slabs with affording` additional support for the mortar dovetail cavities or projections, consisting,` of when applied. the molding-sheet and the surrounding frame x15 Having thus described my invention, the A A B B, made integral with said sheet, and

5 following is what I Claim as new therein and the Whole sheet and frame being` composed of desire to secure by Letters Patent: I soft rubber, substantially as set forth.

1. A mold for forming plaster slabs with l dovetail cavities and projections, consisting THOMAS CURRAN. of the molding sheet and frame made integral, izo and the Whole sheet and frame being com- W'itnesses:

posed of soft rubber, substantially as set HERBERT KNIGHT,

forthb l M. V. BIDGooD.

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