US 3555759 A
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Jan. 19, 1971 KAMBERG ETAL 3,555,759
DIVIDER FOR LIGHT-WEIGHT AGGREGATE BALCONY. FLOORS Filed July 25.- 1969 INVENTORS HL-WRY KAMBEKG,
BY J cK K. W000 v fflion/ TOR/VEKS.
United States Patent Office US. Cl. 52--378 4 Claims ABSTRACT OF THE DISCLOSURE A divider for light-weight aggregate floors of the class having a wood substrate (subfloor) comprising a unitary extended metal strip with a reference upright axis relative to the substrate. An example of such a floor is a balcony. The divider has an attachment flange intended to be attached to the wooden substrate and extends upwardly from the attachment flange so as to include in the following order from the base, a spacer segment, a first (fiat ramp segment sloping away from the spacer segment, a curved key segment, a second flat ramp segment, the flat ramp segments forming an open dihedral between them facing toward the axis, and a fiat terminal segment. Radius segments interconnect the previously recited segments. The curvatures of the various radii and of the key segment minimize stress concentrations in the concrete and the flat ramp segments give greater effectiveness of the divider over the relatively large expansions and contractions encountered with the use of light-weight aggregate. This enables a straight, accurately-located crack to be formed in the light-weight aggregate While still keying the two adjacent sections of aggregate together to prevent their vertical separation.
This invention relates to a divider for light-weight aggregate floors of the type having a wood substrate and a lightweight aggregate atop it.
Flooring of the above type are customarily provided with dividers so as to divide different areas of the surfaces into discrete sections ordinarily defined by a crack which is as straight as possible in the surface. This is a common construction in balconies, sidewalks, roadways, general flooring in multiple-story apartment houses, and the like. The art is replete with solutions to the problems involving the use of dense concrete. However, constructions utilizing light weight aggregate have complications far beyond those involved in the use of dense concrete aggregates for the reasons that thermal expansion and contraction is considerably greater, and that they are laid atop an inherently flexible base namely a wooden substrate or substructure.
Accordingly, previously known devices have proved unsuccessful for use in balcony floors of this class for several important reasons. One is that most of them have had relatively sharp edges which caused stress concentrations which cannot be resisted by the relatively weak concrete aggregate, and chipping and spalling of the flooring structure has been common. Second, because of the buckling which is often a consequence of the common constructions during changes of wetness and of temperature, it has not been unusual for two adjacent concrete structures to pull out of a keying relationship with each other and no longer to join. There then becomes a disjointed and unsightly broken floor. Still another problem is involved with the creation of a straight crack at an accurately determined location during the early cyclings of the floor.
In previous devices, the advantages derivable from the foregoing have not been attainable for the reason that there have ordinarily been compound motions involving both rotation and lateral separation resulting in an un- 3,555,759 Patented Jan. 19, 1971 acceptable separation and breakage of the material. It should be recalled that in floorings of this type the cement layer is relatively thin, ordinarily being no greater than about one and five-eighths inches. Therefore, the present invention must be distinguished between devices utilized in sidewalks and roadways which are generally upward of three inches thick and which use high density concrete. The objective of the structures of this invention is to provide a reasonably strong body of minimum weight because it must often be supported many stories above the ground.
A divider according to this invention is used in connection with a floor having a wooden substrate, this divider having an upright reference axis. It includes an attachment flange that extends laterally and on a first side of the axis and is to be attached to the substrate. In the following order from the attachment flange, there is a flat spacer segment, a flat first ramp segment, a curved key segment, a second flat ramp segment, and a flat terminal segment, the segments all being joined to each other by radius segments, the spacer segment and the flat terminal segment being parallel to the axis and the two ramp segments forming a dihedral opening onto the axis and disposed on the opposite side of it from the attachment flange.
According to a preferred but optional feature of the invention, the attachment flange is perforated to receive nails by means of which the divider is attached to the substrate.
The above and other features of this invention will be fully understood from the following detailed description and the accompanying drawings in which:
FIG. 1 is a cross section of a balcony according to the presently preferred embodiment of the invention;
FIG. 2 is a top view of FIG. 1;
FIG. 3 is an enlarged and detailed portion of FIG. 1; and
FIG. 4 is a top view of FIG. 3.
A floor '10, in this case a balcony floor although according to the invention is shown in FIG. 1 which includes a plurality of wood planks 11 forming a substrate 12 in the nature of a subflooring. Atop the substrate there is poured a layer 13 of light-weight aggregate sometimes known as light-Weight aggregate concrete which forms a wearing surface 14 upon which persons walk, upon which objects may be placed, or upon which another layer such as carpet or linoleum may be placed.
A divider 15 according to the invention is cast into the layer and will form a crack 16 which with the divider itself will divide the layer into sections 17, 18. The crack is shown in FIG. 2 and, while irregular, is generally recognized and accepted as a reasonably straight line. With the properly designed arrangement of this invention, its edges will be free of spalled-out sections and chips, and will form an aesthetically acceptable discontinuity in the flooring. This is good, because such a division is required to prevent an unacceptable crazing throughout the structure such as would otherwise result from thermal expansion and contraction of a monolithic sheet. Furthermore it is accurately located, so as to be properly positioned relative to doorways, intersections of floor coverings, and the like,
The divider is attached to the substrate by means of nails 19 which are driven through perforations 20 in an attachment flange 21. The divider includes a reference axis 22 which is generally vertical relative to the attachment flange and to the substrate. It will be recognized that the divider is an elongated strip such as may be formed by rolling a sheet metal or extrusion of other materials. Therefore, in discussing and defining this invention, the cross section will be referred to, but it will be recognized in a geometric sense as the generator of the entire length.
A flat spacer segment 25 is parallel to the reference axis and departs from the attachment flange. Next in order is a flat first ramp segment 26, a curved key segment 27, a flat second ramp segment 28, and a flat terminal segment 29. The segments are all joined to each other by radius segments and as can best be seen in the drawings the flat spacer segment 25 is joined to the attachment flange by first radius segment 30, the flat spacer segment 25 is joined to the first ramp 26 by second radius segment 31, the first ramp segment 26 is joined to the curved key segment 27 by a third radius segment 32, the curved key segment 27 is joined to flat second ramp segment 28 by a fourth radius segment 33, and the second ramp segment 28 is joined to the terminal segment 29 by a fifth radius segment 34.
Of considerable importance to the design of the invention is the fact that radius 35 of the curved key segment 27 is significantly larger than that of either of the third or fourth radius segments 32 and 33 which should be identical whereby a tongue region 36 is formed in section 18 which is devoid of sharp discontinuities, and the same is true of the groove region 37 in section 17. Similarly, the first and fifth radii are relatively small but still smaller than that of radius 35.
The flat ramp segments provide considerable dimensional stability for the aggregate layer when the lightweight aggregate sections move apart laterally relative to the axis. It should be borne in mind that the thermal coefficient of expansion and contraction of light-weight aggregate is much greater than that of the more compact concrete aggregates, and that more care needs to be taken to provide structural integrity to take advantage of such strength as there is in this relatively lighter material. Accordingly, it has been found advisable especially in view of the fact that in wet climates, or in flexible structures, the substrate can buckle and warp, to provide these flat ramp segments to provide for as great an angular stability as is possible for the adjacent concrete segments sections such as sections 17 and 18 over as large an excursion as possible.
In the prior art devices, completely curved tongues have been formed which do not exert any restriction on angular movement. In the prior art this may have been suitable with compact and dense concrete, but with lightweight aggregate the results of such constructions are that there will be spalling, chipping and failure of the thinner sections of the light-weight aggregate, and often even a complete popping out of register of the tongue and the groove section. With this instant device it has been found that the attachment flange frequently enables the two aggregate sections to be held to the deck over a surprisingly large range of thermal expansions and contrac tions combined with variantly and randomly exerted weight loads atop the aggregate at various regions thereof.
The segments will be continuous unimpeded and imperforate, while the attachment flange may conveniently be adapted for attachment to the substrate by perforations 20 as shown.
Convenient approximate measurements for a device for use in a light-weight aggregate structure having a concrete thickness of approximately one and five-eighths inches is a width of attachment flange of approximately 78'', a height of the terminal point of the terminal seg ment above the attachment flange of about 1 /8", an excursion of the central portion of the key segment from the axis of approximately the radius of the various radius segments of approximately one-eighth inch and a radius of the key segment of approximately one-half inch, the width of the spacer segment about A, and of the terminal segment about Ms".
This device enables a light-weight aggregate structure to be made which is resistant to loads exerted in varying combinations during varying thermal cycles over long periods of time while cracking it between sections along .anaesthetically acceptable reasonably straight line and preventing the popping up of one section relative to another.
What is claimed:
1. A divider for a light-weight aggregate floor having a wood substrate, said divider having an upright reference axis, and comprising: an attachment flange extending laterally and on a first side of said axis which is to be attached to the substrate, a flat spacer segment parallel to said axis, a first radius segment joining the spacer segment to the attachment flange, a flat first ramp segment on the second side of said axis making an acute angle therewith, a second radius segment joining the first ramp segment to the spacer segment, a key segment formed with a radius, a third radius segment joining the key segment to the first ramp segment, a flat second ramp segment making an acute angle with the axis, the two ramp segments forming a dihedral which opens toward the axis, a fourth radius segment joining the second ramp segment to the key segment, a flat terminal segment parallel to said axis and in the same plane as the spacer segment, and a fifth radius segment joining the terminal segment to the second ramp segment, the third and fourth radii being smaller than the radius of the key segment, all of the segments extending as a strip free of discontinuities and interruption.
2. A divider according to claim 1 in which the attachment flange is perforated to receive nails for attaching the attachment flange to the substrate.
3. A floor comprising: a wood substrate, a layer of light-weight aggregate, and a divider attached to the substrate and cast into the aggregate, said divider having an upright reference axis and comprising: an attachment flange extending laterally and on a first side of said axis which is attached to the substrate, a flat spacer segment parallel to said axis, a first radius segment joining the spacer segment to the attachment flange, a flat first ramp segment on the second side of said axis making an acute angle therewith, a second radius segment joining the first ramp segment to the spacer segment, a key segment formed with a radius, a third radius segment joining the key segment to the first ramp segment, a flat second ramp segment making an cute angle with the axis, the two ramp segments forming a dihedral which opens toward the axis, a fourth radius segment joining the second ramp segment to the key segment, a flat terminal segment parallel to said axis and in the same plane as the spacer segment, and a fifth radius segment joining the terminal segment to the second ramp segment, the third and fourth radii being smaller than the radius of the key segment, all of the segments extending as a strip free of discontinuities and interruption.
4. A floor according to claim 3 in which the attachment flange is perforated, and in which nails are driven through at least some of said perforations and into the substrate to attach the attachment flange thereto.
References Cited UNITED STATES PATENTS 1,539,988 6/1925 Bowman 523l8 2,014,841 9/1935 Heeren et al 52-601X 2,031,249 2/ 1936 Bowman 94-3 2,238,355 4/1941 Whitenack 52-318X 3,437,018 4/1969 Jackson 94-17 FOREIGN PATENTS 332,741 7/1930 Great Britain 94--l7 ALFRED C. PERHAM, Primary Examiner U.S. Cl. X.R.