US2359471A

US2359471A - Contractile casting core

Info

Publication number: US2359471A
Application number: US405650A
Authority: US
Inventors: Grant L Ewing
Original assignee: Individual
Current assignee: Individual
Priority date: 1941-08-06
Filing date: 1941-08-06
Publication date: 1944-10-03
Anticipated expiration: 1961-10-03

Description

0(31.v 3', EwlNG CONTRACTILE CASTING CORE Filed Aug. -6, 1941 3 Sheets-Sheet 1 11v VENTOR GRANT L. Ew/Nc; Mn 9 I M fl ATTORNEY Oct. 3, 1944. G. EWING 2,359,471

CONTRACTILE CASTING CORE Filed Aug. 6, 1941 5 Sheets-Sheet 2 m G A? w N M n r T m w m H M W E u m I. T 3 /Y M 6, L A 4 5. T 2 N a 5 4/45 A R m 4 M B a I a 7 mfi$ a u a, W m 8 Mn f/ 7///4/ a a, I W m 5 n J l 7 mm 5 w 47///// 4 63 e I 3 V 4 I a um Oct. 3, G L. W G CQNTRACTILE CASTING CORE v Filed Aug. 6, 1941 s Shets-Sheet s BYGRANTL.EW/NG ATTORNEY Patented Oct. 3, 1944 UNITED STATES PATENT. OFFICE Application August 6, 1941, Serial No. 405,650

Claims.

The invention relates to the structure and application of a contractile core unit which is particularly designed for use in the production of concrete structural elements which are cored out from one edge or between opposite edges thereof.

An object of the invention is to provide a generally improved contractile core structure which is arranged to be contracted as to both width and thickness in the core space of a cast element in a manner to insure its release from the faces of the cored-out space.

Another object is to provide an elongated core structure which is laterally stiff enough for its support solely from and between appreciably spaced points along it without its deflection during a pouring of the concrete into a mold in which it extends.

A further object is to provide a core structure of the type described which is particularly adapted and arranged for its vibration in place during the initial setting of the concrete to provide a settling action of the concrete about it.

An added object is to provide a core structure which is arranged for a slight and controlled contraction thereof following the initial setting of the concrete about it, wherebyto avoid possible damage to the cast element by any setting contraction thereof about the core while having the core in place. 7

Yet another object is to provide a contractile core which is arranged to have supplementary core face elements used therewith for varying the shape and size of the cross-section of the bore provided by it without altering the core structure.

A still further object is to provide a particularly simple method and means for operatively positioning and mounting cores embodying the present features of invention in concrete forms for producing cored-out elements therewith.

The invention possesses other objects and features of invention, some of which, with the foregoing, will be set forth or be apparent in the following description of preferred embodiments and applications of the invention, and inthe accompanying drawings, in which,

Figure 1 is a perspective view of a core struc. ture embodying the features of present invention, the core being contracted.

Figure 2 is a fragmentary longitudinal section of a core taken generally on a plane through the line 22 in Figure 1.

Figure 3 is a fragmentary and longitudinal section taken at the line 3-3 in Figure 1.

Figure 4 is a transverse section at the line 4-4 in Figure 1.

Figure 5 is a transverse section taken as the section of'Figure 3, but with the core in expanded condition.

. Figure 6 1s a fragmentary and broken-away perspective view showing a core operatively associated with a casting form and cast slab.

Figure '7 is a transverse section through a casting mold at the end of a present core therein having supplementary side wall members so associated with the core as to provide a generally square hollow column or beam having its walls of substantially uniform thickness.

Figure 8 is a view similar to Figure 7 and showing the use of supplementary side members with a present core to provide a hollow beam or column of rectangular cross section which is proportionally thicker than the beam of Figure 6.

Figure 9 is a stepped plan view showing cores embodying the present invention operatively installed in a prone wall-molding form in a manner which provides a door opening in the cast slab and is cored out in lines extending parallel to the door opening.

Figures 10 and 12 are sections taken on the lines Ill-I0 and |2| 2 in Figure 9.

Figure 11 is a fragmentary perspective view showing a sheathed end of a core which is used in the arrangement of Figure 9.

Figure 13 is an enlarged fragmentary section of the mold and a cast element thereon taken,,on the line |3-| 3 in Figure 9.

Figure 14 is a fragmentary plan section showing the manner of attaching adjacent slab elements which have been provided by the use of the casting mold of Figures 9 to 12.

Essentially, the present cores |6 are provided for use in cooperation with a mold box to provide cored monolithic elements of concrete. As brought out in Figures 6 and 9, mold boxes I! and H3 are provided for the precasting of slabs l9 and 20 respectively for their subsequent use in building structures. With particular reference to the structure ofthe cores IE, it will be noted that the exterior faces of each core are provided by opposite side elements 2| and 22 and

edge elements

23 and 24 which are shaped of sheet metal or the like and have like lengths in a particular core; for the prone casting of Figures 6 and 9, the side element 2| provides the upper face of the core. The

edge elements

23 and 24 are alike, and are arranged for interengagementwith and between the side edges of the elements 2| and 22 in such a manner that any change of their mutual spacing must be accompanied by a corresponding change in the mutual spacing of the elements 2| and 22, and vice versa.

As shown, edge portions or extensions 25 of the

elements

23 and 24 are turned obliquely inwardly from the intermediate portions 26 of these elements; the element portions-25 and 26 are each flat and of uniform width whereby the nels of regular trapezoidal cross-section. The core elements 2| and 22 have their side edge portions formed to provide channels for complementarily and slidably receiving the portions 25 of the

elements

23 and 24, the intermediate portions 27 of the side elements 2l and 22 being flat and of uniform width longitudinally of the elements.

In the present structure, each intermediate portion 21 of an element 2| or 22 has portions 28 extending oppositely and inwardly from and beyond its side edges. Portions 29 extend angularly toward the inner faces of the elements from the outer edges of the portions 29, and return portions 30 extend from the other edges of the portions 29 in spaced parallel relation thereto to provide trough-like slideways 3| in which the portions 25 of the

elements

23 and 24 are receivable. The portions 25, and the slideways 3| which receive them, are angularly related to the central plane of the core assembly [6 whereby a mutual separation of the

edge elements

23 and 24 in said plane will effect a mutual separation of the elements 2| and 22 transversely of said plane; a reverse action will occur if the

elements

23 and 24 are moved toward each other.

Means are provided for positioning and maintaining the four exterior core elements 2| to 24 inclusive in like engagement at the four slideways 3|, said means essentially comprising a crankshaft 33 extending longitudinally through the core unit and so connected with and related to said elements that its rotation in opposite directions may effect peripheral expansions and contractions of the core. Ears 34 extend transversely inwardly from the portion 21 of the element 22, both adjacent its extremities and at intermediate points therealong, and are provided with mutually aligned perforations in which the shaft 33 is journalled. As indicated in Figure 5, the axis of the shaft 33 is arranged to lie in the central plane of the core, and symmetrically intermediate the

edge elements

23 and 24 when the coreis fully expanded; when the core is collapsed, as in Figure 4, the shaft 33 is closer to the element 2| than to the element 22 which mounts it in fixed spaced rela- 'tion thereto. Ears 35 extend transversely from the ends and intermediate points of the portions'zl of the side element 2| adjacent and in lapped relation to the shaft-mounting ears 34 of the element 22. The ears 35 are provided with slots 36 extending from their free edges and arranged to slidably receive the shaft 33 therethrough; in this manner, the elements 2| and 22 are restrained by the shaft against relative movement in their planes.

Like disc members 31 are fixed on the shaft 33 adjacent the ears 34 of the element 22, and links 38 connect diametrically opposed crankpins 39 provided on the discs 31 with pivot pins "49 provided on corresponding members 4| extending from the inner faces of the intermediate portions 26 of the

different edge elements

23 and 24 in rigid relation to the elements. The eccentricityof the crankpins 39 is the same for both, and the pins '49 are at the same distances from the portions 26 of the different elements 2 3 and 24. When the core assembly is fully expanded, as in Figure 5, the pivot pin 40 are arranged to ment 2|.

limiting core-expanding position, a dead center locking of the expanded core against its collapse by lateral pressure results. When the core is contracted, the plane of the crankpins 39 is rotated about the shaft axis to thereby, through the action of the links 38, draw the

elements

23 and 24 toward each other to like degrees and so correspondingly draw the elements 2| and 22 toward each other to thereby simultaneously decrease both the width and thickness of the core. As a further and more positive means to lock a present core in fully expanded condition, portions of

corresponding ears

34 and 35 of the

core side members

22 and 2| respectively which are mutually overlapped when the core is fully and symmetrically expanded may be provided with registering holes for removably receiving and retaining locking pins 42 transversely of the engaged ears.

Since the central plane of the

edge elements

23 and 24 must move toward the intermediate portions 21 of the element 22 as the core is collapsed, means are preferably provided to maintain the intermediate portions 26 of the

edge elements

22 and 23 in perpendicular relation to the core plane. As particularly illustrated, the inner ends of the members 4| are laterally expanded to provide forks 43 which receive the shafts 33 in their slots and have their slot sides so engaged by eccentric cam members 44 fixed on the shaft in their planes that the members 4| are retained in the common plane of the core while it is contracted or expanded; when the core is contracted, said plane lies between the shaft axis and the intermediate portion 21 of the element 22, this being evident in Figure 4. In this manner, an appropriate rotative adjustment of the shaft 33 between limiting positions is arranged to contract or'expand the core as desired while maintaining the core elements in mutually fixed angular relations to each other to insure a symmetrical core form and avoid distortion or undue friction during a size adjustment of the core.

It will now be noted that the present core structure is such that it is substantially rigid against lateral flexure between spaced points thereon, whereby it may be engaged with and between opposite sides or ends of a mold space without danger of bending when the concrete is poured, and/or tamped about it. In the latter connection, it is to be particularly noted that the somewhat zig-zag edge structures which provide the slideways 3| for the side elements 2| and 22 stiffen the elements thereat and that the channel form of the

edge elements

23 and 24 stiffen these elements against flexure, particularly when their portions 26 engage the grooves 3| of the elements 2| and 22. The present arrangement, taken with the spreader action of the ears 34 and crankplate 31 centrally along the

sides

22 and 7 2| respectively, permits the forming of the core elements from thinner material than would be possible if the elements are notstiffened in, the

the inner face of the intermediate portions 21 of the element 2| as the core is expanded to prevent an inward deflection of said portion to- As particularly illustrated, the crank' disc 31 has its profile 48 so formed as to engage ward the shaft. 'With the intermediate portions 21 of both the side elements 2| and 22 held spaced from the shaft, inward deflection of the core side portions 2! is prevented, and the form of said portions is maintained against any outer pressure which may be exerted against thereon during the casting of a cored slab with the present core.

At one or both ends, and beyond the

shaftengaging cars

34 and 35, the crankshaft 33 is provided with a socket 45 for receiving the complementarily formed bit end 46 of a suitable wrench 41 for application to adjustably rotate the shaft and so vary the core periphery as re quired. With the present arrangement,'a slight contraction of the core is possible after the primary setting of the concrete occurs whereby to provide against self-damaging contraction of the cast element about the core without rendering the core completely inoperative.

By particular reference to Figure 6, a core I6 embodying the present invention is shown as applied in the casting of a rectangular concrete element 99 which is cored out between opposite edges thereof. In this case, the fragmentarily shown element i9 is provided in the space of the mold box I! having a bottom and ends 52 and sides 53, only one side 53 being shown, and the upper edges of the box ends and sides are coplanar to define the upper face of the slab. At appropriate and opposite points therein, the box ends 52 are provided with openings 54 for closely and complementarily receiving an expanded core therethrough to extend between the aligned openings. In this manner, the length of the slab is determined as the distance between the opposed inner faces of the sides 52, and the core extremities, being external to the box space, need not be sealed against the entry of the plastic concrete in the box. It will be understood that this arrangement, by reason of the inherent stillness of the present cores I5, permits the casting of straight and relatively long concrete elements which are longitudinally cored.

It may, at times, be desirable to provide in a cast element a cored opening which is larger than an available present core. Under these circumstances, members 55 may be mounted on and against the outer faces of the side core'portions 26 to increase the cross-section of the bore provided by the core between the mold ends by the use of such members, whereby the same contractile core structure may be used to provide cored openings of different sizes. This use of members 55 is brought out in the showing of Figure 7, wherein such members are shown as applied against opposite faces of an expanded core [5 which is utilized in providing a hollow column or beam [9 in the box l1. As particularly illustrated, the core sides may be provided with projections 55 for engagement in complementary sockets of the members 55 for securing the members against lateral shifting upon the core sides which they engage. In the present instance, the members 55 are of trapezoidal crosssection with their sloping faces arranged for alignment with the outer faces of portions 28 of the core side elements 2! and 22. A member 55 is shown as mounted on the core element H5 in Figure 6.

It Will, 75

of course, be evident that the auxiliary core mem bers might be segmental in cross-section or. have other sections in accordance with the form of core to be provided. By the use of such supplement'ary elements 55, it will be understoodthat the same collapsible core may be utilized to provide bores of various cross-sections, and so re-v duce the cost of producing cored concrete structure elements of various sizes and shapes.

' Figures 9 to 14 relate to the production and features of the element 25 which comprises a wall slab providing an opening fora door andis precast in the mold box [8. 'As particularly illustrated,,the mold box I8 comprises a casting floor 6| which supports side boards'62 intermediately connected by endboards 63 and 54 to define top and bottom edges for the slab 20; Form boards and'fifi and Bl extend from the floor 6| into the mold space to respectively define the two sides and top of a door opening in the slab 20. The cores it which are utilized at the sides of the door opening are longer than the height of the wall slab and extend through complementary openings in the mold boards .63 and 64 in the previously described manner. The cores I6 may be of different widths as is illustrated. A similar arrangement might provide a window opening interiorly of the slab.

Cores 56 are also utilized to core-out the wall slab portion above the door openings. As particularly illustrated, a board 68 extends from the casting floor between the side mold boards 62 at a point beyond the end mold board 63, and the

boards

63 and 88 are provided with mutually aligned sets of openings for complementarily receiving cores I6 through and between them. The core end portions within the mold space between the

boards

63 and 68 extend to points appropriately spaced from the form board 67 which is arranged to define the top of the door opening.

Caps of p-aper'or the like enclose the extremities of the latter'cores Within the mold space to prevent the entry of unset concrete within the cores, such caps being usable whenever the relatively open core end is to be enclosed in a cast element. Also, a suitable sheet Hi of paper or the like, may be provided at the bottom of the mold space to produce a more finished under face for the cast slab. Suitable reinforcement members H are provided and suitably mounted in the mold space about the core portions within the mold. It is to be particularly noted that the engagement of these cores through the

boards

63 and 68 provide a cantilever support for the core portions in proper position within the mold space with the inherent stiffness of the core structures preventing their deflection by reason of the placement of the initially plastic or fluid concrete in the mold space.

While the cores l6 have been particularly shown as being used in prone position, with their side faces horizontal, it will be understood that the cores might be used in erect position, or in prone position with their side faces other than horizontal. Also, the present cores may be used for providing cored structural elements in place rather than as precast elements. In whatever situation the present cores are used, the application of the hammer Of a vibrator (not shown) to the shaft 33 Of a core is arranged to transmit the imposed vibrations to all parts of the core face whereby the unset concrete may be settled preliminary to its setting, and a compacted and homogeneous concrete slab may result. novel method of providing a compacted casting This by transmitting settling vibrations to'the unset material directly through the core has been found particularly valuable for insuring the production of uniform cast concrete products.

By particular reference to Figures 12 to 14, it will be noted that the slab 28 is provided along its side edges with longitudinal grooves 8| into and beyond which loop members 82 extend for mutual overlapping with like loops extending from an abutting like slab in a structure built up of the slabs, the overlapped loop portions receiving a tieing rod or bar 83 through them as a keying or tieing means connecting the slabs against separation thereat. For providing the slab grooves 8|, the present side form members 62 are formed with longitudinal grooves 84 at the mold faces thereof, and back metallic face plates 85 having intermediate portions offset oppositely from the grooves 83 to define the groove 8| in the slab. A present loop member 82 comprises a return bend of rod, and has its extremities extend through the plates 84 into the mold space for suitable anchorage in the cast slab. When the form is removed from about a cast slab 20, the plates 85 are also removed as a form part.

The present mold form also provides for the integral installation of a metallic frame to case the door, or other, opening of the cast slab. As brought out in Figure 13, the mold faces of the

form boards

65 and 66 and 61 are grooved out to receive the stepped jamb portion 81 of a casing strip 88. Side casing portions 89 of the strip 88 extend from the edge of the portion 81, and the other edges of the portions 89 are provided with inturned flanges 9| for anchoring embodiment in the cast slab. Wire ties 92 may connect the flanges 9| at spaced points therealong for embedment in the slab to further insure a retention of the strip 88 on the slab as a casing in and for the opening.

From the foregoing description taken in connection with the accompanying drawings, the advantages of the construction and method of use will be readily understood by those skilled in the art to which the invention appertains. While I have described the features and applications of a contractile core which I now consider to be a preferred embodiment of my invention, I desire to have it understood that the showing is primarily illustrative, and that such changes may be made, when desired, as fall within the scope of the following claims.

I claim:

1. A contractile casting core comprising four 7 exteriorside members constantly providing the entire peripheral surface of the core and having the side edge portions of adjacent said members mutually engaged in direct interfitting slidable relation therealong for maintaining their engagement in fixed angular and sealed relation thereat, a control shaft extending within the core space and rotatably carried by one said member in fixed spaced relation thereto, and operative connections between the shaft and solely the mem bers which engage the shaft-carrying member such' that opposite rotations of the shaft will positively and similarly move the latter members toward or from eachrother to contract or expand the core while positively maintaining a constant angular relation of all of said side members.

2. A contractile casting core comprising four exterior side members constantly providing the entire peripheral surface of the core and having the side edge portions of adjacent said members mutually and directly engaged therealong in in.- terfitting slidable relation for maintaining their engagement in fixed angular relation, a control shaft extending within the core space and journalled on one said member in fixed relation thereto, operative connections between the shaft and solely the members which directly engage the shaft-carrying member such that opposite rotative movements of the shaft will positively and similarly move the latter members toward or from each other to contract or expand the core, and cam-like spacing members carried by the shaft and automatically operative between the shaft and against the fourth said member in an intermediate longitudinal line thereof to prevent an inward deflection of the member thereat when the core is expanded.

3. A contractile casting core comprising exterior side members constantly cooperative to provide the entire peripheral surface of the core and having the side edge portions of adjacent said members mutually engaged in interfitting slidable relation peripherally of the core for maintaining a sealed engagement thereat while the core is expanded or collapsed, a control shaft extending longitudinally Within the core space and journalled in a said member in fixed relation thereto, operative connections between the shaft and solely the members which engage the shaft.- carrying member such that opposite rotative movements of the shaft will positively move the latter members toward or from each other to contract or expand the core, and arm members extending rigidly from the latter members in fixed angular relation thereto and s0 engaging the shaft that the angularity of the latter members to the first members peripherally of the core is held constant as the shaft is rotated to contract or expand the core.

4. A structure in accordance with claim 3 whereof the arm members are longitudinally slotted at the shaft, and the shaft provides an eccentric disc engaging in the slots of the arm members to maintain the arm members in the same angular relation as the core is contracted or expanded by a rotation of the shaft.

A peripherally contractile tubular casting core comprising four exterior side members constantly providing the entire peripheral surface of the core and having the side edge portions of adjacent said members mutua1ly engaged in direct interfitting slidable relation therealong for maintaining their engagement in fixed angular relation as the core is contracted or expanded, a crank shaft extending through the core space longitudinally thereof and rotatably carried by one said member in fixedly spaced relation thereto, and links connecting the crankpins of the shaft with solely the members which engage the shaft-carrying members in such a manner that opposite rotations of the shaft will positively and similarly move the latter members toward or from each other to uniformly contract or expand the core, said crank pins being arranged to pass through dead-center positions thereof with respect to the shaft axis and corresponding link connections with the core side members when the core is substantially fully expanded. V

GRANT L.,EWING.