US2895324A - Building constructions - Google Patents

Description

M. ROSENSWEIG BUILDING CONSTRUCTIONS July 21, 1959 Filed Jan. 25, 1952 2 'sheetssheet 1 INVEN TOR. 4446K fiswowi/e BY p a c a July 21, 1 5 M. ROSENSWEIG BUILDING CONSTRUCTIONS 2 Sheets-Sheet 2 Filed Jan. 23, 1952 IN V EN TOR.

JTfOIVA/f llLl l I l I l I United States Patent BUILDING CONSTRUCTION S Mack Rosensweig, New .York, N.Y., assignor to Ameray Corporation, a corporation of New Jersey Application January 23, 1952, Serial No. 267,801

3 Claims. (Cl. 72-9-38) This invention broadly relates to building construction and especially to building blocks, which may be termed ray-protective or ray-proof, for use in structures intended to .be proofed against emission of X-rays, gamma and other dangerous rays used in medical and experimental laboratories, and to the method of and means for producing such ray-protective building blocks.

Ray-protective building blocks as such are not unknown in the art. They usually consist of two monolith portions made of a light concrete mixture, and held between these monolith portions is a sheet of ray-barring material such as lead, varying in thickness depending upon the intensity of the rays intended to be blocked from penetrating beyond the structure built from these blocks.

One of the important requirements in wall structures made from such ray-protecting blocks is the positive absence of ray leakage, for which reason the sheet of the blocks must have a suffi cient overlap to prevent any ray penetration.

Numerous attempts have been made to assure such by the use of anchors driven through the sheet and preferably soldered in place, and which anchors project into and are imbedded in the bodies of the monolith portions. Anchoring elements used in that manner very often become subject to corrosion and may, under certain conditions, cause porosity of the lead sheets which results in ray leakage.

The present invention contemplates the elimination of the above-outlined and other serious defects now found in existing ray-proof block constructions and in addition to reduce the cost of such ray-proof blocks and render them more effective, easier to handle in the erection of walls, while assuring a positive overlap of the lead sheets and a ready interlock of the blocks without resorting to costly structural arrangements and without employing anchoring elements for the lead sheets.

One of the basic objects of the present invention is the provision of a ray-proof building block which consists of two monolith or cast portions which are substantially alike in body shape and dimensions but which are offset relative to one another to expose two marginal edges of each of the two portions, and between which portions there is placed a sheet-like lead core or plate, the latter being immovably held between the block portions without the employment of anchoring elements, and wherein two opposite corners of the plate extend beyond the bodies of both monolith block portions.

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Another object of this invention is the method of producing the outlined block structure.

A still further object of this invention is the provision of. means for effectively practicing that method.

The foregoing and numerous other objects and important advantages of the present invention will be more fully understood from the ensuing description in conjunction with the accompanying drawings, which latter are held in a more or less diagrammatical form and are by no means intended to limit this invention to the actual showing, and wherein:

Fig. l is a perspective illustration of a prismatic body indicating the two like component parts from which the future ray-proof block of the present invention is formed;

Fig. 2 is a perspective view of a finished ray-proof wall block produced in accordance with the present invention;

, Fig. 3 is atop view of a wall block;

Fig. 4, is a left-hand end 'view thereof;

Fig. 5 is a top end view thereof;

.Fig. 6 is a right-hand end view thereof;

Fig. 7 is a bottom end view thereof;

Fig. 8 illustrates a partial wall structure made from blocks shown in Figs. 2 and 3;

Fig. 9 is a typical, enlarged, top view of a portion of the wall structure as shown in Fig. 8 with the upper row of blocks indicated in broken lines;

Fig. 10 is a top view of a portion of a wall structure employing, in addition to the blocks shown in Figs. 2 and 3, rectangular corner blocks;

Fig. 11 is a. similar top view to that shown in Fig..l0 showing the use of obtuse corner blocks;

Fig. 12 is a top view of a mold employed in the production of the blocks shown in Figs. 2 and 3;

Fig. 13 is a section taken approximately along lines 1-3-13 of Fig. 12;

Fig. 14 is a top view of a mold for producing a rectangular corner block;

Fig. 15 is a section taken approximately alongline 15-15 of Fig. 14; and

Fig. 16 is a section taken along lines 1616 of Fig. 15.

In order to explain the manner the ray-proof building blocks of the present invention are constructed, Fig. 1 is illustrated to show that the two monolith halves of the futurejblock are formed by passing through a square prismatic block a plane at such an incline that it will divide the block into two identical halves, that is a lower half 10 drawn in heavy lines and an upper half 11 drawn in light limes. Each half of the prismatic block constitutes a peripherally square prism truncated along an inclined plane. The two identical block halves illustrated in Fig. 1 rest against each other along that truncating, inclined plane and their outer faces are disposed in two uniformly spaced parallel planes. As shown in Figs. 2, 4, 5, 6 and 7, these block halves can be offset in a certain manner relative to one another along that inclined truncating plane, without altering the parallel relation of their outer faces. The two thus equally divided block portions or block units will have oppositely disposed highest corners a and a, and in alignment with these highest corners will be the lowest corners d and d. The right-hand corner of the lower unit 10 is indicated at b which is somewhat shorter than corners a and a and equal in height to the opposite corner b of the upper unit 11. Adjacent to corners b and b are corners c and c of the lower and upper block units, respectively, which are shorter than corners b and b but are higher than the lowest corners d and d.

By shifting or offsetting the upper and lower block units in respect to one another along a diagonal vertical plane, which latter is normal to the parallel outer faces of the units, and in which diagonal plane are located diagonally opposite corners b and c of unit and corresponding corners b and c of unit 11, these units will assume the position illustrated in Fig. 2. That offsetting of the units along the diagonal vertical plane causes the separation of the corner pairs a and d and d and a located intermediate between the diagonally offset corners b and c and c and 12'. Thus two corner gaps are formed between these intermediate corner pairs.

As can be readily conceived from Fig. 2, intermediate corners a and d of unit 10 are diagonally opposite to one another and are located in a vertical plane which is normal to the diagonal vertical plane passing through corners b and c of unit 10. Similarly, intermediate corners a and d of upper unit 11 are located in a vertical diagonal plane which is normal to the vertical diagonal plane passing through corners b and c of unit 11. Thus the two vertical planes in which lie the two intermediate corners of thetwo units are in parallelism.

In addition to the corner gap formations between. the intermediate corner pairs of the units, the offsetting of these units produces four converging marginal edge areas, constituting portions of the adjacent inclined faces of the units. Obviously each of the marginal edge areas are differently inclined and extend between the correspondingly converging spaced peripheral body edges of the two units, as will be presently evident.

In Fig. 2 there is shown a lead interlayer or core 12 in the form of a planar or flat plate which is placed between the two adjacent inclined faces of the two units. That interlayer is fixedly attached to these inclined faces in any suitable manner, such as by an adhesive or binder, whereby the units are permanently secured to one another. I p I Interlayer 12 fully covers the aforesaid marginal edge areas of both units, its right-hand corner 13 coinciding with corner [2 of lower unit 10, while its opposite corner 14 registers with corner b of upper unit 11. Moreover corner area 15 of the interlayer extends over and seals the corner gap formed between intermediate corners a and d of the upper and lower unit, respectively. Likewise the opposite corner area 16 of interlayer 12 extends over and covers or seals the corner gap formed between corners a and d of the lower and upper unit, respectively.

Due to the fact that all four corners of each block unit are different in height, the truncating plane referred to in connection with Fig. l and which plane substantially corresponds to the center plane passing through lead core 12, is oriented in more than one direction. That fact can be easily verified by consulting Fig. 2. It will be seen that core or flat plate 12 slants in the direction from the upper point or upper end of corner a of lower block unit 10 toward the upper point or upper end of corner d; it also slants in the direction from upper end of corner I) to the upper :end of corner d; it further slants from upper end of corner c toward the same upper end of corner d. Thus it becomes evident that both the truncation plane dividing the block into identical units, and the center plane passing through core 12 (Fig. 2) slant in three distinct different directions. Consequently all four above referred to marginal ledge areas resulting from the diagonal offsetting of the units, and which areas extend between the peripheral edges of the shifted units, slant in dilferent directions, as clearly shown in Fig. 2. Thus the marginal edge area of unit 10 progressing from the upper end of corner a to the upper end of corner b is inclined differently from the marginal edge area starting at the upper end of corner b and terminating at the upper end of corner a.

A similar directional divergence exists between the marginal edge areas at the undersurface of unit 11, in that the marginal edge area commencing at the lower end of corner a." and terminating at the lower end of corner b= slants differently from the marginal edge area between the lower end of corner b and the lower end of corner a.

The three-directional orientation of the truncation plane (Fig. 1) and the resulting square-prismatic and truncated shapes of the adjacent block units, as seen in their offset position in Fig. 2, are chosen advisedly, since through these combined new features new and most advantageous results are effected. First, the square shapes of the block units facilitate their ready positioning relative to each other during the formation of courses in a masonry structure so that they can be set, with the usual application of mortar, into substantially edge-adjacent position along oertain of their four edges, which are of equal length. Secondly, the three-directionally oriented planar interlayers of any two adjacent blocks, although spaced by mortar, virtually automatically overlap one another as the block edges are brought into adjacent position, whereby a sturdy, uniform structure is produced, the outer surfaces of which are smooth, even and progress in two uniformly spaced, continuous planes. The formation of such structure is effected without resorting to a special shaping of both the marginal edge areas of the blocks and of their interlayers, as is required in heretofore employed blocks in the production of similar masonry structures. Thus the laying of block courses or block rows is effected expeditiously, even by unskilled labor, at a substantial saving in cost, time and effort, when blocks of the present invention are employed.

Thirdly, the three-directional orientation of the joined block surfaces and of their interlayers facilitates a ready positioning of blocks in one row in respect to blocks in any adjacent block row, in that the adjacent block edges of one row can be located anywhere between the adjacent block edges of the next adjacent row. When such positioning is maintained uniformly throughout the formation of the entire structure, the outer faces thereof will lie in two continuous, uniformly spaced parallel, continuous planes. Moreover, due to the three-directional orientation of the block interlayers, the edge portionsof the interlayers of one block row will automatically overlap the edge portions of the interlayers of the next adjacent row, thus automatically effecting a triple overlap of the edge portions of the interlayers along the meeting areas of any two adjacent rows, whereby light leakage is positively prevented. Also this third advantageous result of the present disclosure is achieved at a minimum expenditure of time, effort and cost, since the blocks in one row are readily fitted together with the blocks of each next adjacent row, all without the requirement of specially shaping the marginal block areas and correspondingly bending their interlayers, as is necessary in prior art block structures for similar purposes.

The positioning of the blocks and of their interlayers in the process of erecting wall or similar structures from the present block units will be readily understood when referring to Figs. 8, 9, 10 and 11.

Fig. 3, which is a plan view of the block shown in perspective in Fig. 2, clearly illustrates the relative posi-' tion of the two block members 10 and 11 and of the lead core 12. All the end views shown in Figs. 4, 5, 6 and 7 further elucidate the relative position of the end faces of the two block portions and of the lead core. However, it should be noted that the incline of the plane along which the two block portions are joined is vastly exaggerated over the incline actually used in the production of the block, such incline being determined by the thickness of the lead core to be used, to assure correct overlap of adjacent lead cores and maintain the outer block surfaces in even, vertical parallel planes. In Figs. 3 to 7 the corners of the block portions and of the lead core are marked with the same indices as those shown in Figs. 1 and 2 so as to leave no doubt as to the relative position of the block portions and their corners.

In Fig. 8 a portion of a wall is shown comprising four blocks. The blocks of the lower row are indicated by letters A and A, while the blocks of the upper row are marked B and B.

The same designation of the blocks is employed in Fig. 9, wherein blocks A and A form an upper block layer and are shown in full lines, whereas the blocks B and B constitute the lower block layer and are partly indicated in broken lines. It will be observed from the disposition of the two block layers that at the junction of blocks A and A the lead cores of the blocks overlap at X, but they are also overlapped by the third lead core of block B, and that at the juncture of blocks B and B the respective lead cores of these two blocks overlap at Y and are additionally overlapped by the lead core of block A. The fact that the adjacent surfaces of each two block portions are inclined in the manner stated above, facilitates a smooth overlap of the three layers of lead cores, as at X and Y, without the necessity of bending or otherwise altering thelead core bodies, and in addition assures the ready erection of walls with perfectly aligned outer block surfaces.

As will be observed from Figs. 8 to 11, the monolith portions of the blocks are always spaced from one another. These spaces are filled with a binder or mortar for securely connecting the blocks with one another. That spacing of course is relatively narrow so that an ample overlap of the lead cores of adjoining blocks and in all directions is assured.

In Fig. 10 is illustrated a corner of a Wall structure constructed from blocks of the present invention and including a rectangular corner block C composed of an outer portion 17, an inner portion 18 and a lead core 19 which latter extends partly beyond portion 17 at 20 and beyond portion 18 at 21 so as to effect an overlap with the lead cores of adjacent full-sized or half-sized wall blocks, indicated at 22 and23, respectively.

As will be noted, the blocks and their interlayers are spaced slightly by mortar M, which is also employed for finishing the outer Wall surfaces formed by the blocks.

In Fig. lla wall structure with an obtuse corner is shown, in which is employed an obtuse corner block piece D, again composed of an outer member 24, an inner member 25 and a core 26 which extends beyond inner block portion 25, to eflect an overlap with core 12 of full block element A.

Also in this figure mortar M is employed for cementing the blocks in place and for finishing the outer wall surfaces.

The method of producing ray-proof blocks Contrary to the heretofore used practice of first casting monolith block portions in which are imbedded anchors for holding the lead core, the present method comprises what may be termed a wet process of block production. A suitable mixture of the future monolith material is prepared and one-half or one portion of the future block is cast and tamped. Before the latter is permitted to setthere is applied to its upper surface a binder, such as a self-setting plastic composition, and over that binder there is placed the lead core. Now more of the plastic binder is applied to the upper surface of the lead core and the other half or portion of the future monolith block is cast over the lead core and tamped down. While both of the block portions are still wet and while the binder applied to the top surface of the first-cast block portion and to the top surface of the lead core is not yet set, the block structure in its wet condition is subjected to a curing or hardening process which takes place in the atmosphere at normal room temperature. The curing is effected by the setting of both the block mixture as well as of the binder for holding the core in place between the two monolith bodies. A period of twelve to forty-eight hours is required to cure the block which is then ready for packing, shipping or use in the erection of walls .to totally destroy the latter.

The composition from which the two future monolith block portions is made preferably comprises a waterabsorbent setting agent such as Portland cement, plaster of Paris, or a mixture containing either or 'both, and a relatively porous, lightweight filler, such as cinder, ash, slag. The binder applied to the first-cast, wet block portion and to the upper surface of the core before the other block portion is cast thereon, contains preferably a readily self-setting rubber or other plastic composition which is advantageously applied not in the form of a full layer, but in the form of dabs evenly distributed over the surfaces intended to be joined. As the material of the future monolith "block portions hardens, the binder penetrates into the wet block composition and also hardens and forms anchor-like connections between the core and the block bodies, thus securely holding the lead core in place.

Tests have proven beyond any doubt that the two block portions and the interposed lead core become inseparably united. Even the hardest abuse and even cracking of the concrete block portions will not affect the union between the three elements of the block. Further tests have proven that in order to remove the lead core from between the two concrete portions it became necessary By following the above outlined method steps, a substantially indestructible rayproof block is produced.

Means for fabricating ray-proof blocks In Figs. 12 to 16 there are shown two typical structures of molds for producing ray-proof blocks according to the present invention. Formaking blocks shown in Figs. 2 to 9 the mold structure illustrated in Figs. 12 and 13 is used. That mold is preferably supported upon a platform 27 provided with an aperture for accommo dating the table of an hydraulic lift device indicated at 28. Upon that lift table rests a pallet 29. supported by means of rollers 30 mounted in the table. Pallet 29 serves as the bottom support of the future block while the latteris being cast and during the time ofbeing cured. Surrounding pallet 29 is a mold frame composed of a stationary member 31, shown in Fig. 12, a left movable member 32, another movable member 33 opposite member 31 and still another movable member 34 opposite member 32. All movable members 32, 33 and 34 are preferably hydraulically operated. All four sides of the mold comprise lower and upper portions, as can be plainly observed from Fig. 13. In addition, upper parts 33' and 34' of frame members 33 and 34, respectively, are hinged, as at 33" and 34" so that they may be swung out of the Way for reasons which will be explained presently.

.In fabricating the block, first hinged members 33 and 34 of the movable mold portions 33 and 34 are swung outwardly to provide access to the lower portion of the mold indicated at 35 in Fig. 13. That lower portion is completely filled with a cement mixture of the composition stated previously. Now a self-setting plastic binder is applied to the upper surface of the still wet lower east portion of the future block, whereupon lead core 12 is placed on top thereof. Now the hinged portions 33 and 34' are turned into the position shown in Figs. 12 and 13. Thereupon the plastic self-setting binder is applied to the upper surface of lead core 12 and the upper half of the mold 36 is filled completely with the cement mixture. The future block is now complete. All three movable sides of the mold are now moved outwardly to their broken-line position shown in Fig. 12 so that only stationary wall member 31 remains, and hydraulic lift 28 is operated to elevate the cast block above the mold structure until pallet 29 upon which the block rests assumes the broken-line position shown in Fig. 13. Since pallet 29 is supported by rollers 30, it can be now moved onto a conveyer (not shown) to a place Where the block is tobecured. The curing, as stated before, consists of permitting the block material as well as the binder to set and dry while the block rests upon the pallet. Now the lift is moved downwardly into its normal position shown in Fig. 13, and another pallet is placed over the rollers and the three movable walls of the mold are brought to their position shown in full lines in Figs. 12 and 13 ready for the molding operation of another block.

The illustrations in Figs. 14 to 16 denote a mold for casting a corner block. The mold body again rests upon a platform 37 and is composed of a base 38 provided with an inclined recess 39 into which fits a form or frame 40 which is hinged at 41. Connected with the upper right-hand portion of the block are two frames, a lower frame 42 and an upper frame 43 which are hinged at 42 and 43, respectively. Opposite the hinged connection of the two frames and removably associated with the lower end of base 38 is a removably mounted end block 44 preferably held in place by wing nut bolts 45, operative in guides 46. Between right-hand hinged member 43 and end block 44 there is arranged another hinged member 47 hinged at 47, as can be clearly seen from Figs. 14 and 16, and opposite hinged member 47 is a stationary mold wall 48.

Beneath mold frame 40 there is arranged an hydraulic lift 49 which is adapted to elevate it. Supported by the lower leg of frame 40 is a pallet 50 shown in full lines in its first position and in broken lines in its elevated position to which it is raised by lift 49.

In casting a corner block, first hinged members 43 and 47, shown, respectively, in Figs. 15 and 16, are swung out of the way, whereupon cement material is placed into frame 40 to form a corner structure corresponding to the shape of the lower half of the mold. (See Fig. 15.) Now to the top surfaces of the thus cast half block is applied a self-seting plastic binder, whereupon an angularly bent lead core is placed over the cast concrete. Members 43 and 47 are swung back into place and plastic binder is applied to the upper surfaces of the lead core. Thereupon the upper portion of the mold is filled with concrete material, thus completing the block structure. Now block 4-4 is moved to the left, see Fig. 15, and all hinged members 43, 42 and 47 are swung outwardly, whereupon lift 49 is caused to elevate pallet th, upon which the block rests, into the position shown in broken lines. The thus supported block is then moved, by suitable means, not shown, in the direction toward and beyond wall member 47 to be picked up by a conveyer (not shown) on its way to a curing place.

To make the mold ready for the next block casting operation, hydraulic lift 49 is caused to move downwardly so that frame 45) reassumes its full-line position, end block 44 is clamped in place, and the hinged frame portions are swung back to their position shown in Fig. 15. Thereupon the above described procedure is repeat-ed.

From Figs. 8 and 9 as Well as from Figs. and 11 it will become readily evident that the present block construction, be it that of a full or half block or a corner iblOCk, is designed so that the edge areas of any two adjacent blocks assume approximately parallel relation to one another, that the edge areas of the cores or interlayers of any two adjacent blocks will overlap one another, although they are slightly spaced by mortar cementing the blocks in place, and that the outer faces of the blocks are co-planar and form continuous outer wall surfaces. As stated previously, the block material comprises a plasticized, self-setting composition of a water-absorbing cement-like ingredient as a binder, mixed with a rather voluminous and preferably porous filler. The thus compounded composition will have the tendency of readily setting and drying.

Considering now the application of the binder applied to the wet mass of one of the block portions and to the top surface of the colr e'upon which the wet mass j of the presently preferred form, their structural features of the other block'portion. rests, experiments and tests have shown that the plastic binder material actually penetrates into the still wet, unset block portions and sets so-to-speak' simultaneously with the material of the plasticized block components. The binder obviously also securely adheres to the lead core, whereby 'those portions of the binder which penetrate into the block composition virtually form anchors for the core which is securely held between and to the block material when both the latter as well as the binder set and dry. In that manner the core becomes inseparable from the block components.

.The thickness of the blocks and the thickness of the core between the block components will be governed by the particular application and requirement prescribed by the future users and therefore the structure of the block is subject to variations and changes.

While the molding devices shown and described are are subject to alterations, depending upon the type of blocks to be produced. Thus, for instance, a mold for an obtuse corner block will have to be suitably designed. It will be therefore understood that the drawings of both mold structures illustrated are primarily presented for the purpose of facilitating the description of the modus operandi in efiiecting the fabrication of ray-proof blocks in accordance with the present invention, and are by no means intended to limit the instant disclosure to the specific structures shown.

By the same token, the organization of the several block elements may require alterations in adapting them for erection of different wall structures. Such alterations in the block elements may also affect certain stages of the above described method, requiring changes and improvements. All such possible deviations from the matter outlined in this specification are deemed to reside within the broad scope of the present invention as defined in the appended claims.

What is claimed as new is: v

l. A building block, comprising in combination two identical monolithic cementitious units joined with one another along one of their faces by way of a planar interlayer disposed between their adjacent faces, each of the units constituting a square, right-angle truncated prism, each of the four corners of which being of a different height, whereby the joined adjacent faces of the.

units as well as the said interlayer are caused to assume a position along an inclined plane oriented in three different directions, the outer faces of the units being planar and being disposed in uniformly spaced parallel planes, the units being offset relative to each other along a diagonal plane normal to their outer faces so that two diagonally opposite aligned corners of one unit located in said diagonal plane become spaced from two corresponding diagonally opposite aligned corners of the other unit, and which latter corners are also located in said diagonal plane; that offsetting of the units along said diagonal plane causing the corner pair intermediate between the aligned corners of one unit to shift in respect to the corresponding intermediate corner pair of the other unit whereby the intermediate corner pairs of the two respective units assume positions in spaced parallel planes normal to the said first mentioned diagonal plane, and whereby corner gaps are formed between these intermediate corner pairs of the two units; that offsetting of the units further causing the formatic-n, at portions of the inclined adjacent faces of both units, of converging marginal edge areas extending between correspondingly converging spaced peripheral body edges of the two units, each of said converging marginal edge areas being inclined in different direc-.

tions', and wherein said interlayer not only covers said marginal edge areas of both units, but extends with two of its corn-er areas beyond the aforesaid marginal edge areas and seals the corner gaps formed between the intermediate corner pairs of the units.

2. A building structure produced from building blocks as defined in claim 1, said structure consisting of at least one row of said blocks set in substantially edge adjacent relation to one another, and wherein the interlayers of any two adjacent blocks are in overlapping relation to each other, and wherein the outer faces of the blocks of all rows are co-planar.

3. A building structure produced from building blocks as defined in claim 1, said structure consisting of at least two adjacent rows of said block, and wherein the blocks of each row are substantially in edge-adjacent relation to each other, and wherein the blocks of one row are so positioned relative to the blocks of the next adjacent row that the adjacent areas of blocks in one row overlap the edge areas of the blocks in the next adjacent row, and wherein the interlayers of any two adjacent blocks in any one row overlap one another, and wherein the overlapped interlayers in that one block row overlap the overlapped interlayers of the blocks in the next adjacent row, thus effecting automatically 8. triple overlapping of interlayers along the joining area of each two adjacent block rows while the structure is 10 being formed, and wherein the outer block faces of all blocks in every block row throughout the entire structure are co-planar.

References Cited in the file of this patent UNITED STATES PATENTS Re. 18,349 Lapof Feb. 9, 1932 826,639 Worster July 24, 1906 915,570 Dryden Mar. 16, 1909 1,798,661 Duryea Mar. 31, 1931 1,889,745 Chapman Dec. 6, 1932 1,902,178 Nelson Mar. 21, 1933 2,018,192 Sexton Oct. 22, 1935 2,232,837 Brassert Feb. 25, 1941 2,280,635 Ishman Apr. 21, 1942 2,290,339 Leach July 21, 1942 2,466,106 Hoge Apr. 5, 1949 2,577,323 Goenner Dec. 4, 1951 2,583,912 Weiss Jan. 29, 1952 FOREIGN PATENTS 164,125 Great Britain of 1921 681,138 France of 1930

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