US 2785842 A
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March 19, 1957 c. A. PHELPS 2,785,842
- LADDERS FOR CONCRETE STRUCTURES F 'iled July 29,' 1955 IN V EN TOR. (2/1005 A l l /1 P5 A TTO/P/YE Y United rates Patent LADDERS FOR CONCRETE STRUCTURES Claude A. Phelps, Birmingham, Mich.
Application July 29, 1955, Serial No. 525,302
1 Claim. (Cl. 228-45) This invention relates to ladder construction and in particular to improved ladder construction for concrete structures.
Ladders for concrete structures such as manholes, tanks, bins, wharves, dams, retaining walls, buildings and the like are generally built by forming suitable U-shaped steps from round rods, bending anchor hooks on the ends thereof and inserting the bent ends of the said U-shaped steps through the form defining a surface of the concrete structure to be poured, and concreting the steps in place. This method of construction usually requires special forming at the ladder steps and prevents the stripping of the forms after pouring the concrete structure without damage to the form. If steel wall forms are used, special provisions are required at the ladder steps, and rapid stripping and moving of the forms to adjacent portions of the structure to be poured is quite difiicult and time consuming. Furthermore, it is not practical to incorporate safety features in ladder steps constructed as above indicated.
With the foregoing in view, the primary object of the invention to provide improved ladder construction for poured concrete structures in which the ladder steps may be readily built and installed with a minimum of man hours of labor, and in which required safety features may be incorporated at substantially no additional cost.
A further object of the invention is to provide improved economical ladder construction for poured concrete structures which does not require special forming and in which the ladder steps are readily replaceable.
Other objects of the invention will become apparent by reference to the following detailed description taken in connection with the accompanying drawing, in which:
Fig. 1 is a plan view of the improved ladder construction for poured concrete structures embodying the invention, certain portions being shown in section to illustrate the invention more clearly.
Fig. 2 is a horizontal view part in elevation and part in section of the improved ladder step construction taken on the line 2-2 of Fig. 1.
Fig. 3 is a cross sectional view taken on the line 33 of Fig. 1.
Referring now to the drawing wherein like numerals refer to like and corresponding parts throughout the several views, the ladder construction embodying the invention consists of the combination of specially formed U-shaped ladder steps engaged in suitable cast iron or cast aluminum inserts 11 concreted into the poured concrete structure 12, the said inserts 11 being secured at the proper spacing to a form (not shown) for the concrete structure 12 prior to pouring the same. After the concrete structure 12 has been poured and has set, the forms are stripped leaving pairs of inserts 11 in the structure 12 ready to receive ladder steps 10 as hereinafter described.
Each insert 11 is preferably provided with a suitable anchor 13 at the rear thereof to assure its firm and permanent anchorage into the concrete structure 12. The body of the said insert 11 is provided with a cavity 14 and preferably has downwardly and inwardly sloping 2,785,842 .Tatented Mar. 19, 1957 ice side Walls 15. The insert 11 has a vertically disposed T-slot 16 formed in the front wall 17 thereof. The rear wall 18 of the insert 11 is preferably perpendicular and parallel to the front thereof; however, the rear of the front wall 17 is tapered sloping from being relatively thin adjacent the head of the T-slot 16 to relatively thick adjacent the bottom of the said T-slot 16. This construction makes the cavity 14 of the insert 11 generally wedge shaped at the rear of the front wall 17 each side of the stem or shank of the said T-slot 16 therein.
The U-shaped ladder steps 10 are formed of cast iron or cast aluminum, and preferably have a safety tread cut or cast in the top of the rung 18 thereof as shown in Figs. 1 and 3. At the outer ends of the rung 18 are upstanding safety nubs 19 which prevent the foot of a person using the ladder from accidentally sliding sidewards from the said rungs 18. The rung 18 of each U-shaped ladder step 10 is supported on outstanding arms 20 formed integral therewith, each arm 20 being provided with a T-shaped head 21 wherein the overhang of the T is sloped at 219 complementary to the slope of the rear 170 of the front wall 17 of the insert 11. Spaced from the said T-shaped head 21 of each arm 20 and depending therefrom is an apron 200, the rearwardly disposed face of which abuts the front of the front wall 17 of an insert 11 when the Tshaped head 21 of the said arms 20 of the ladder steps 10 are inserted in the cavity 14 of the said insert 11 and wedged downwardly therein, whereupon the said ladder steps 10 are firmly supported in cantilever relationship from the said inserts 11. As indicated in Fig. 3 only, after the T-shaped heads of the arms 20 of the U-shaped ladder steps 10 are wedged into the inserts 11, the cavities 14 of the inserts 11 may be filled with a mastic cement or other suitable material 22 that may be removed therefrom to permit ready replacement of a ladder step 10 should one become broken.
Although but a single embodiment of the invention has been disclosed and described herein, it is obvious that many changes may be made in the size, shape, arrangement and detail of the various elements of the invention as defined by the appended claim.
In a ladder for poured concrete structures, a pair of laterally spaced inserts embedded in a concrete structure with the front walls of said inserts disposed parallel to the surface of said structure, each insert having a cavity therein and a T-slot through said front wall thereof communicating with said cavity, the inner portions of the front wall adjacent the stem of said T-slot being tapered forming within said cavity laterally spaced female wedges, a U-shaped ladder step comprising a transverse rung portion and a pair of rearwardly disposed arms, each of said armsincluding a T-shaped portion at its inner end sloped each side the stem thereof forming a pair of laterally spaced male wedges engageable with the laterally spaced female wedges of an insert, each arm including an apron depending therefrom having a rearwardly disposed face which abuts the front of an insert when the said male spaced wedges of said arm are positioned in the cavity of the insert and urged into engagement with the female spaced wedges thereof.
References Cited in the file of this patent UNITED STATES PATENTS 793,770 Covert July 4, 1905 990,267 Hill Apr. 25, 1911 1,141,554 Klumpp June 1, 1915 1,178,368 Williamson Apr. 4, 1916 1,639,210 Brown Aug. 16, 1927 1,727,296 Matte, Jr. Sept. 3, 1929