US2288991A - Mold for cementitious material - Google Patents

Description

July 7, 1942. o. s. BURMAN MOLD FOR CEMENTITIOU S MATERIAL Filed Nov. 18, 1940 2 Sheets-Sheet l nvenior' 0107 151' Barman By fiMAfforneyJ M WM July 7, 1942. o. s. BURMAN 2,288,991

MOLD FOR CEMENTITIOUS MATERIAL Filed Nov. 18, 1940 2 Sheets-Sheet 2 2/ w I Jnvniar Z0 Olaf v31 Barman By lil'dflborneya 'l' l .".'IIIIE"IIIIIIII III// Patented July 7, 1942 UNITED STATES PATENT OFFICE MOLD FOR CEMENTITIOUS MATERIAL Olof S. Burman, Minneapolis, Minn.

Application November 18, 1940, Serial No. 368,101

6 Claims.

My present invention provides a highly efficient mold for the casting of cementitious materials and, generally stated, consists of the novel devices, combinations of devices, and arrangement of parts hereinafter described and defined in the claims.

Particularly the invention is directed to the provision of a mold for casting concrete or cementitious laundry tubs with either single or multiple compartments, as desired. Hitherto molds for casting of such cementitiou tubs have involved an outer shell and an inner shell or core arranged to be properly spaced for the pouring of the fluid concrete or cementitio-us material; but such molds have not been well adapted for the casting or molding of tubs having in wardl projecting shelves.

My invention relates particularly to the structure of the inner shell or core and provides improvements in the inner shell or core, whereby the casting of the tub with inwardly projecting shelf is made an easy matter and in which scams or joints in the visible interior of the tub will be eliminated. This improved feature involves a ledge plate hingedly connected to the main body of the inner shell or core but which, when turned to an inoperative position, will permit the inner shell or core to be readily removed from the interior of the cast tub.

The above ledge-forming plate is preferably made somewhat shorter than the width of the tub compartment and for an important reason, which will hereinafter more fully appear, the core is formed with openings at the ends of the ledge plate and these openings are arranged to be closed by corner plates to complete the core for molding action.

A commercial form of the improved mold is illustrated in the accompanying drawings wherein like characters indicate like parts throughout the several views.

Referring to the drawings:

Fig. 1 is a view in perspective, but with some parts sectioned, showing the elements of the improved mold turned upside down for the purpose of molding the tub which latter is also indicated in Fig. 1;

Fig. 2 is a view in perspective showing the inner shell or core removed from working position and turned right side up;

Fig. 3 is a fragmentary section taken on the line 33 of Fig. 2;

Fig. 4 is a fragmentary view in plan showing in detail certain parts found in the immediate vicinity of one side of Fig. 2;

Fig. 5 is a section taken through the inner shell or core on the line 55 of Fig. 2 and showing in section also the molded or cast tub from which the outer shell has been removed;

Fig. 6 is a view corresponding to Fig. 5 but showing by dotted lines the adjustments of the elements of the inner shell for removal from the cast or molded tub; and

Fig. 7 is a detail in horizontal section taken on the line 'l'! of Fig. 2.

The cast or molded tub is indicated by the numeral [0 and is formed with an integral inwardly projecting shelf H. The tub here illustrated is of the general character disclosed and claimed in my Design Patent No. 117,329 of October 24, 1939.

My improved mold is especially adapted for the molding of tubs of the above character, to wit: tubs with inwardly projecting shelves such as are frequently designated as soap trays.

The outer shell of the mold is made up of side plates I2 connected at their ends by end plates l3, the outer shell thus formed being normally opened at bottom and top. In practice, it has been customary to rigidly but detachably connectthe plates I2 and I3 at their abutting edges. This outer shell is arranged to rest upon the bars M of a rectangular base frame, shown as made up of angle irons. The bars M are shown with raised aligning ribs or ledges It which properly locate the outer shell when it is seated on the base frame in an inverted position, as shown in Fig. 1. In Fig. 1 the side plates l2 are shown as reinforced by angle bars or ribs it.

The inner shell or core H is made of such form that it will be spaced from but it will be parallel to the plates of the outer shell, thereby leaving the proper space for the casting of the tub. The normal bottom of this inner shell I! is closed, but when the inner shell is inverted, as shown in Fig. 1 and placed upon the frame [4, its downturned edges will be just inward of the aligning ribs l5 and the two shells will be properly spaced for the molding of the tub.

To form the top of the shelf II the inner shell is formed with a rigid inwardly projecting plate I8 which, as shown. is additionally supported and made rigid with the inner shell by bars l9. As best shown in Fig. 2, the normal top of the inner shell H has edge flanges inturned at I1 and which flanges, when the inner shell and core is inverted as shown in Fig. 1, rest directly on the bars 14. Just below the plate |8 the back of shell or core I! is cut away at to form a space for the hinged ledge plate 2| and for end blocks or pieces 22. The ledge plate 2| is hingedly connected at 23 to the rear wall of the inner shell or core IT. The end blocks 22 fit in the ends of the recess 20 and are flanged to correspond to the cross-section of the ledge plate 2|, to the ends of which they are arranged to be aligned. The hinged ledge plate 2|, at its free edge, see Fig. 5, is arranged to be aligned with the downturned edge flange l8 of the fixed plate |8, thereby properly spacing the said elements l8 and 2| for forming the shelf I.

As a simple means for locking the ledge plate 2|, in the position just stated and as shown in Fig. 5, a lock-bolt 24 is shown as pivotally connected thereto and provided with a nut 25. When nut 25 is loosened, bolt 24 is arranged to be turned into a notch 26 of a metal strap 21 which is shown as rigidly secured to and projects from the fixed plate l8.

To detachably but securely hold the end blocks or plates 22 in working positions, they are shown as provided with pivotally connected levers 28 that are adapted to be turned against the end walls of the inner shell and under spring-acting retaining flanges 29 secured on the interior of the end plates of the said inner shell.

The use of the improved mold is probably obvious from the foregoing statements, but may be briefly summarized as follows:

Inner and outer shells are applied on the base frame M, as already described, with the end blocks and the ledge plate locked in the operative positions stated, and then the concrete or cementitious material is poured into the mold through the open top of the outer shell and against the inverted bottom of the inner shell. When the interior of the mold has been properly filled, the bottom of the tub, which is then inverted, will be levelled off and the tub allowed to set in its inverted position until it is properly set or hardened; then the outer shell will be first removed; next, the formed tub with the inner shell applied will be turned right side up and the inner shell will be removed from the tub. As clearly shown in Fig. 6 by dotted lines, the removal of the inner shell or core is made an easy matter when the end blocks or plates 22 have first been removed and then the ledge plate 2| is turned first downward to the position indicated by full lines in Fig. 6, thereby permitting the inner shell or core to be removed, as indicated by dotted lines in said view.

In the forming of multi-compartment tubs, two or more of the inner shells or core-forming elements will be placed within the outer shell, spaced apart properly for the forming of the tub partitions. Of course the outer shell will be made in a length proper for forming tubs of the desired number of compartments. The most common form of the tub will, of course, be a two-compartment tub which would require two of the above described inner shells or cores.

The outer surfaces of the corner blocks 22 are flush with the end plates of the core and with the ends of the ledge plate 2| and fit the same with close joints so that there will be very little seam line formed on the interior of the tub; and, moreover, even these slight seam or joint lines are entirely under the shell H, and hence, will not be within the line of vision of a person using or inspecting the tub. Seam or joint lines on the interior of the tub, where in full View, are very objectionable and all such are avoided in the use of my improved mold.

In actual practice this improved tub has been found to be highly efficient and to very greatly reduce the amount of labor required in forming laundry tubs of the character referred to. It will, of course, be understood that a preferred form of the mold above described is capable of various modifications Within the scope of the invention herein disclosed and broadly claimed.

What I claim is:

1. In a tub molding device, an inner coreforming shell having inwardly projecting upper and lower shelf-forming plates extended along one wall of said shell, said lower plate being displaceable to permit removal of said shell after the molded tub with inwardly projecting shelf has set and hardened.

2. In a tub molding device, an inner coreforming shell having inwardly projecting upper and lower shelf-forming plates extended along one wall of said shell, said upper plate being relatively fixed to said shell and said lower plate being displaceable to permit removal of said shell after the molded tub with inwardly projecting shelf has set and hardened, said lower plate being made in sections and including an intermediate portion and corner-forming end blocks having independent securing means.

3. The structure defined in claim 1 in which said displaceable lower shelf-forming plate is hingedly connected to the back of said inner shell and is provided, at its free edge, with means for detachably locking the same to said upper shelf-forming plate.

4. The structure defined in claim 1 in which said displaceable lower shelf-forming plate is hingedly connected to the back of said inner shell and is provided, at its free edge, with means for detachably locking the same to said upper shelfforming plate, and in further combination with corner blocks set into the side Walls of said inner shell at the ends of said displaceable lower shelfforming plate.

5. The structure defined in claim 2 in which said upper shelf-forming plate is provided with a projecting notched lug and said displaceable lower shelf-forming plate is provided with a nut-equipped bolt engageable with said notched lug to lock said two shelf-forming plates in cooperative shelf-forming position,

6. The structure defined in claim 1 in which said displaceable lower shelf-forming plate is hingedly connected to the back of said inner shell and is provided, at its free edge, with means for detachably locking the same to said upper shelf-forming plate, and in further combination with corner blocks set into the side walls of said inner shell at the ends of said displaceable lower shelf-forming plate, said corner blocks having projecting lock levers pivoted thereto and the sides of said inner shell having retaining clips with which said levers are fric tionally engageable to detachably hold said corner blocks in operative positions.

I OLOF S. BURMAN.

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