US3006115A

US3006115A - Screed chair

Info

Publication number: US3006115A
Application number: US19139A
Authority: US
Inventors: Hillberg Bror
Original assignee: Superior Concrete Accessories Inc
Current assignee: Superior Concrete Accessories Inc
Priority date: 1960-03-15
Filing date: 1960-03-15
Publication date: 1961-10-31
Anticipated expiration: 1978-10-31

Description

1961 B. HILLBERG SCREED CHAIR Original Filed Aug. 20, 1956 BROR HILLBERG 36 5 \50 y y w:

3,0t6,1l5 SCREED CHAR Bror Hillberg, Elmwood Park, Ill, assignor to Superior Concrete Accessories, Inc., a corporation of Delaware Continuation of application Ser. No. 604,982, Aug. 20, 1956. This application Mar. 15, 1960, Ser. No.

3 Claims. (Cl. 50322) The present invention relates generally to screed chairs of the type which are designed for use in connection with the formation of concrete slabs or other concrete bodies. More particularly, the invention is concerned with mechanical screed holders of the two-part separable type wherein there is provided a lower screed chair base and an upper screed holder proper, the former being adapted to be positioned on the supporting surface and the latter being detachably mounted on the base in such a manner that it may be removed from the base and withdrawn from the concrete after the latter has become set or partially set, thus leaving the base structure embedded in the concrete as an expendible item but serving the incidental function of reinforcing the poured concerete mass.

Heretofore, screed chairs of this general character have been possessed of certain limitations, principal among which are the inability of the holder to maintain the supported screed element firmly and fixedly in position against floating on the poured concrete, and also the inability of the screed holder proper to be removed from its lower screed chair base without appreciably disturbing the surface of the poured material so that refinishing operations of a substantial character must be resorted to after removal of the screed. An additional limitation that is attendant upon the construction and use of screed chairs of this general character resides in the fact that the upper screed holder part and the lower chair base part have threaded engagement with each other through the medium of a threaded shank and socket arrangement, thus necessitating extensive winding operations, first when the upper part is assembled and adjusted on the lower part and, secondly, during disassembly of the parts and withdrawal of the upper screed-supporting part from the base part. Furthermore, with screed chairs of this sort, the screed must be lifted from the usual cradle structure provided for it on the removable portion of the holder before the latter can be withdrawn from the poured cement so that, where large expanses of concrete surface area are concerned, it is necessary to walk on the partially set concrete with the attendant danger of the creation of footprints which must be erased by costly refinishing operations. Additionally, the provision of mating threaded surfaces on the upper and lower parts of the two-part separable screed chair is costly from the standpoint of actual use inasmuch as frequently the larger particles of concrete infiltrate the threaded region of the parts and cause binding of the parts so that it is necessary to utilize tools which are capable of applying a high degree of torque to the upper part before it can be removed from the lower part and withdrawn from the concrete.

The present invention is designed to overcome the above-noted limitations that are attendant upon the construction and use of present day screed chairs of the two-piece separable type and, toward this end, it contemplates the provision of a screed chair having separable parts as outlined above wherein, after the chair has been operatively positioned in a concrete installation and the concrete poured and partially set, the upper part or screed holder proper may be removed from the lower base part and withdrawn from the poured concrete with a minimum of effort and Without appreciably disturbing the surface contour of the concrete body.

nited Smtes atent O 3,06,115 Patented Oct. 31, 1961 'ice The provision of a screed chair of the character briefly outlined above being among the principal objects of the invention, another object is to provide such a chair wherein the chair base is formed entirely from flat sheet metal stock and rod stock with the various parts thereof being welded together and characterized by the absence of rivets, threaded fastening devices, individual clamps and the like, thus contributing toward economy of manufacture. A similar and related object is the provision of such a chair base including two identical sheet metal stampings, each of which may be formed by a simple die stamping operation, with the two parts being welded to gether to form a rigid compact socket-forming member designed for cooperation with the upper screed-holding part to loosely receive therein a projecting portion of the latter whereby the two parts are releasably held in their assembled relation, the construction and assembly of the socket-forming member further contributing toward economy of manufacture.

A further object of the invention is to provide a screed chair of this character wherein, after the upper part has been assembled upon the lower chair base in an actual installation, the elevation of the upper screed-supporting part may be varied by a simple manual operation utilizing interengaging threaded members on one of the parts only for effecting the adjustment so that thereafter the upper part may be separated from the chair base with out requiring unthreading of the members or, in fact, any relative rotation of the parts which otherwise would disturb the surface contour of the concrete of the installation.

Yet another object of the invention is to provide a screed chair of the separable shank and socket type wherein the shank portion of the upper screed supporting part is threaded and receives thereon an adjusting nut adapted to rest on the rim of the socket provided in the base part for adjusting purposes and in which the nut further serves the purpose of preventing infiltration of grout into the socket portion after the concrete has been poured and prior to withdrawal of the upper part.

Another object of the invention is to provide a screed chair of the two-part separable type in which the upper part has associated therewith an open screed-supporting cradle member adapted initially to receive the screed and having formed thereon bendable screed-clamping fingers capable of being distorted into screed-engaging position whereby the screed is firmly clamped in the cradle against longitudinal or other shifting movement as well as against floating after the concrete is poured. Another and related object of the invention is to provide a screed chair of this sort wherein the clamping means just referred to also serves as a lifting means whereby one or more of the upper screed-supporting parts associated with a series of the chairs may be disassociated from their respective base parts and withdrawn from the poured concrete by manipulation of the screed itself and without necessitating actual contact with any portion of the screed chair.

With these and other objects in view which will become more readily apparent as the following description ensues, the invention consists in the novel construction, combination and arrangement of parts shown in the accompanying single sheet of drawing forming a part of this specification.

In this drawing:

FIG. 1 is a perspective view of a two-part screed chair constructed in accordance with the principles of the present invention; 7

FIG. 2 is a perspective view of one of the parts, namely, the actual screed-supporting part, shown in FIG. 1;

FIG. 3 is a sectional view taken substantially along the horizontal plane indicated by the line 3--3 of FIG. 1; and

FIG. 4 is a sectional view taken vertically through a 3 freshly poured concrete body and showing the improved screed chair in its operative position with respect to a screed and embedded within the concrete body.

Referring now to the drawing in detail, the screed chair illustrated therein constitutes a preferred embodiment of the invention. It is designed to support a cylindrical pipe type screed S. In its general organization, the chair is comprised of two main parts or assemblies, namely, a lower chair base and an upper screed-supporting or cradle part 12. As is customary with screed of this type, the screed S is utilized as a reference surface so as to properly orient a straight edge bar or device (not shown) by means of which freshly poured concrete which cooperates to make up a slab S2 may be levelled when supported on a surface S3 provided, for example, on a wood or plywood deck S4.

The base part 10 is adapted to be supported on the surface 83 during pouring of the concrete for the slab and is adapted to remain embedded in the latter and form a reinforcement for the same. It may be nailed or otherwise anchored to the surface S3 and is comprised of a socket assembly 13 and a plurality of generally inclined downwardly and outwardly diverging legs 14 by means of which the socket assembly 13 is supported in an elevated position above the surface S3. The socket assembly is comprised of two identical

sheet metal stampings

16 and 16, respectively, each having a medial semi-cylindrical portion 20 and a pair of laterally extending flanges 22 which are oppositely directed in the same plane. The side flanges of the two

stampings

16 and 18 are secured to each other in face-to-face relation as by welding at 24 so that, when so secured, the stampin-gs form, in effect, a hollow cylindrical tube providing a central bore 26 and having diametrically disposed radial composite side flanges 28. The legs 14 include vertical posts 30 which merge into the legs proper and are welded or otherwise secured as at 32 to the composite flanges 28 on opposite sides thereof to form a quadruped structure having outwardly and upwardly turned foot portions 34 formed at the lower ends of the legs. The foot portions 34 facilitate nailing of the chair base to the surface S3. Transverse reinforcing rods or struts 36 connect adjacent pairs of legs 14 in the medial regions thereof.

When the chair base 10 is fixedly secured in position on the supporting surface so that it rests squarely thereon as shown in FIGS. 1 and 4, the axis of the cylindrical bore 26 extends vertically and the bore provides in effect a socket designed for reception of the shank portion of the upper part 12 or screed support proper, as will be described presently.

The upper part 12 involves in its general organization a screed cradle 44 which may be in the form of a sheet metal stamping of generally U-shape cross section and having a semicircular base portion 42 and upstanding sides 44, the outer ends of which are slotted as at 46 so as to provide a series of bendable tongles or fingers 48 capable of being bent in wrap-around fashion, as illustrated in FIG. 4, so that the screed S which is initially loosely received within the cradle 40 may subsequently be clamped therein against longitudinal shifting or vertical floating movements when the screed is. in use in a concrete installation. Reference to FIG. 4 will disclose the fact that the depth of the sheet metal cradle stamping 46 is greater than the radius of the screed S, and that the over-all length of the U-shaped cradle stamping, including the semi-circular base portion 42 and the upstanding side portions 44, is less than the circumference of the screed. The radius of curvature of the base portion 42 is, of course, substantially equal to the radius of the screed so that the latter will seat or nest within the cradle stamping with a snug fit. For these reasons, when the fingers 48 are bent over the upper region of the screed, they will not overlap, but instead, a slight gap between the ends of each pair of opposed fingers will be left so that an unbroken exposed longitudinal screed edge will remain available for sliding movement therealong of a strickle bar without interference by the upper ends of the fingers 48.

Attached by Welding to the underneath side of the cradle 40 and centered with respect thereto is a depending threaded shank 50, the threads 52 of which are of relatively long pitch. The shank 50 receives thereover an adjusting nut 54- which is preferably of hexagonal design so that it may receive thereover a conventional adjusting tool, such as a wrench or the like.

In using the screed chair in connection with the formation of a slab S2, the chair base 10 is nailed or otherwise secured in its erect position on the supporting surface S3, as previously described, and in alignment with a series of similar chair bases. Thereafter, the shank portion 50 of the cradle part 12 is loosely inserted Within the cylindrical bore 26 afforded by the mating semicylindrical portions of the two

stampings

16 and 18 so that the underneath face of the nut 54 rests on the rim of the bore 26. The nut is then adjusted to bring the screed cradle 40 to the proper height and the various cradles associated with the aligned series of such cradles are individually turned and brought into axial alignment so that they may receive therein one of the elongated screed pipes S. It is contemplated that in the various adjustments involved the extreme upper portion of the screed S will be flush or coplanar with the desired top level of the slab 32. When the screed S is in position within the various cradles 40, the tongues 48 are bent inwardly so that they will become wrapped around the cylindrical surface of the screed as shown in FIG. 4 to hold the latter firmly against longitudinal shifting or floating. It is to be noted that the free ends of the tongues 48 do not meet or overlap when the bending operation is completed and, therefore, it is possible, if desired, to check the alignment of the screed pipe S, utilizing a straight edge tool for this purpose.

After the assembled screed holders have been thus mounted on the supporting surface S3, the concrete is poured until it builds up to the upper portion of the screed, which is the desired level, and, in order to properly surface the slab, a straight edge is moved across the screed or across adjacent screeds in the usual manner of surfacing such slabs. The concrete is allowed to partially harden or set and, when the same has reached the desired degree of plasticity, the various upper parts 12 of the screed holders are removed from their respective base portions 10 by pulling the same vertically upwardly so that the shank portions 59 are withdrawn from the cylindrical bores 26 and from the partially hardened concrete. This removal operation may be performed without manually engaging the individual cradles 46 inasmuch as a mere lifting operation of the screed S will suffice, through the medium of the tongues 48, to elevate the cradles and their attached parts. It is thus unnecessary to traverse the surface of the concrete with the attendant leaving of footprints or otherwise marring the surface of the slab.

It is to be noted that the nut 54 serves as a seal over the upper end of the cylindrical bore 26 of the base part 10 when the concrete is poured so that there will be no seepage of concrete into the bore, thereby facilitating easy removal of the shank St} at the time screed removal operations are in effect.

The invention is not to be understood as restricted to the details set forth since these may be modified within the scope of the appended claims without departing from the spirit and scope of the invention.

This application is a continuation of patent application Serial No. 604,982, filed August 20, 1956, and entitled Screed Chair and now abandoned.

Having thus described the invention what I claim as new and desire to secure by Letters Patent is:

1. A two-part, separable composite screed chair for for maintaining a screed in fixed elevated position over a supporting surface in connection with the formation of a concrete body, said chair comprising a lower chair base adapted to be positioned on the supporting surface and to remain embedded in the concrete body after the concrete has been poured and become set, and an upper cradle part designed for removal from the chair base and withdrawal from the concrete body when the latter has become partially set, said chair base comprising a pair of semi-cylindrical sheet metal members each having radially extending side flanges on opposite sides thereof coextensive with the longitudinal extent of the member with the side flanges being disposed in a common plane, said members being positioned one against the other with said pairs of side flanges being disposed in coextensive face-to-face relationship and welded together so that the members define therebetween a vertically disposed open-ended tubular body providing a central bore having smooth vertical walls, with said welded flanges on each side of the body constituting radially outwardly projecting and longitudinally extending ribs having oppositely facing fiat sides, a plurality of supporting legs of cylindrical rod stock having upper vertical lengths extending longitudinally along and welded to the sides of said ribs, said vertical lengths merging with downwardly and outwardly extending intermediate lengths and said intermediate lengths terminating at their lower ends in laterally extending foot portions adapted to rest on said supporting surface below the lower end of said tubular body whereby the latter is supported in an elevated position above the supporting surface, said upper cradle part comprising a cradle proper adapted to receive the screed therein and an elongated shank depending from said cradle proper and threaded throughout its vertical extent, and an adjusting nut threadedly received on said shank, said shank being loosely and slidably received within said bore with the nut resting on the rim of the latter whereby turning movement of the nut will vary the elevation of said cradle proper.

2. In combination, a cylindrical screed and a twopart, separable composite screed chair for maintaining the screed in fixed elevated position over a supporting surface in connection with the formation of a concrete body, said chair comprising a lower chair base adapted to be positioned on the supporting surface and to remain embedded in the concrete body after the concrete has been poured and become set, and an upper cradle part designed for removal from the chair base and withdrawal from the concrete body when the latter has become partially set, said chair base comprising a pair of semi-cylindrical sheet metal members each having radially extending side flanges on opposite sides thereof coextensive with the longitudinal extent of the member with the side flanges being disposed in a common plane, said members being positioned one against the other with said pairs of side flanges being disposed in coextensive face-to-face relationship and welded together so that the members define therebetween a vertically disposed openended tubular body providing a central bore having smooth vertical walls, with said welded flanges on each side of the body constituting radially outwardly projecting and longitudinally extending ribs having oppositely facing flat sides, a plurality of supporting legs of cylindrical rod stock having upper vertical lengths extending longitudinally along and welded to the sides of said ribs, said vertical lengths merging with downwardly and outwardly extending intermediate lengths and said intermediate lengths terminating at their lower ends in laterally extending foot portions adapted to rest on said supporting surface below the lower end of said tubular body whereby the latter is supported in an elevated position above the supporting surface, said upper cradle part comprising a cradle proper within which the cylindrical screed is seated and an elongated shank depending from said cradle proper and threaded throughout its vertical extent, and an adjusting nut threadedly received on said shank, said shank being loosely and slidably received within said bore with the nut resting on the rim of the latter whereby turning movement of the nut will vary the elevation of said cradle proper, said cradle proper comprising an upright sheet metal stamping of U-shape cross section having a base portion to which the cradle shank is welded and having outwardly extending side portions, said side portions being slotted inwardly to provide a series of bendable fingers, the depth of said U-shape stamping being greater than the radius of said screed and the overall length of said U-shape stamping including said base and side portions being less than the circumference of the screed, said fingers being bent inwardly over the upper portion of the screed Without overlapping so as to provide an unbroken longitudinal screed edge for sliding movement therealong of a strickle bar, said fingers serving frictionally to hold the cradle proper to the screed so that upon lifting the screed, the cradle part including the shank will be pulled bodily upwardly from the partially set concrete body, allowing the chair base to remain embedded in the concrete body.

3. In combination, a cylindrical screed and a two-part separable composite screed support for maintaining the screed in fixed elevated position over a supporting surface in connection with the formation of a concrete body, said screed support comprising a lower base part and an upper cradle part for holding the screed elevated above the supporting surface, said base part comprising a tubular member having a smooth cylindrical bore, said base part being adapted to be received on the supporting surface with said bore extending vertically, said upper cradle part comprising a cradle proper within which the cylindrical screed is seated, an elongated shank depending from said cradle proper and threaded throughout its 'ver tical extent, and an adjusting nut threadedly received on said shank, said shank being loosely and slidably received within said bore with the nut resting on the rim of the latter whereby turning movement of the nut will vary the elevation of said cradle proper, said cradle proper comprising an upright sheet metal stamping of U-shape cross section and having a semi-cylindrical base portion to which the cradle shank is welded, said stamping presenting outwardly and upwardly extending side portions which are slotted inwardly from their upper edges to provide a series of bendable fingers, the radius of curvature of said semi-cylindrical base portion being substantially equal to the radius of the cylindrical screed, the depth of said stamping being greater than the radius of said screed and the overall length of said U-shape stamping including said base and side portions being less than the circumference of the screed, said fingers being bent inwardly over the upper portion of the screed without overlapping so as to provide an unbroken longitudinal screed edge for sliding movement therealong of a strickle bar, said fingers serving frictionally to hold the cradle proper to the screed so that upon lifting of the screed, the cradle part including the shank will be pulled bodily upwardly from the partially set concrete body, allowing the base part to remain embedded in the concrete body.

References Cited in the file of this patent UNITED STATES PATENTS 1,123,107 Darr Dec. 29, 1914 1,810,287 Mahon et al. June 16, 1931 2,257,421 Mabry Sept. 30, 1941