US 3299984 A
Description (OCR text may contain errors)
Jam. 24, 1967 c. SVEDAHL STEP INSERT FOR CONCRETE PIPE SECTIONS Filed Jan. 2, 1964 INVENTOR. CL/FFOPD L. -VEDA HL BY %M AT TOR/VEKS United States Patent 3,299,984 STEP INSERT FOR CONCRETE PIPE SECTIONS Clifford L. Svedahl, 2116 3rd Ave. S., Minneapolis, Minn. 55404 Filed .Ian. 2, 1964, Ser. No. 335,257 1 Claim. (Cl. 182-92) My invention relates generally to the concrete pipe molding art, and more specifically to molded concrete pipe sections used in the formation of vertically extended passages normally interposed between an underground sewer and the overlying ground surface, and known in the art as manholes.
In order to facilitate passage through such manholes, it is necessary to secure ladder-forming rungs to the radially inner surface of the concrete pipe sections forming same. It is conventional practice to insert such rungs in operative positions after the pipe sections have been molded and by chopping away the walls thereof, recementing, etc. Such procedure not only is time consuming and costly, but also produces rungs which are frequently insecurely anchored and unsafe.
The primary object of my invention is the provision of a novel anchoring plate which is adapted to be imbedded into the wall of a concrete pipe section during the molding thereof, and a cooperating step-forming member which may be readily detachably secured to the anchoring plate at any time subsequent to the molding operation.
A further object of my invention is the provision of a device of the class immediately above described which is relatively inexpensive to produce and which may be installed in pipe sections in a minimum of time and with a minimum of skill and instruction.
A further object of my invention is the provision of a device of the class described which is rugged and durable and which provides -a maximum of safety to users thereof.
The above and still further objects of my invention will become apparent from the following detailed specification, appended claims, and attached drawings.
Referring to the drawings wherein like characters indicate like parts throughout the several views:
FIG. 1 is a fragmentary view of the anchoring plate of my invention imbedded in operative position in a pipe section, portions thereof broken away and shown in section;
FIG. 2 is a view in vertical section taken on the line 22 of FIG. 1, showing a portion of the mold;
FIG. 3 is a view in vertical section as seen from the line 33 of FIG. 1, showing a portion of the mold;
FIG. 4 is a View corresponding to FIG. 1, but showing the step-forming member added thereto, portions thereof broken away and shown in section;
FIG. 5 is a view in horizontal section as seen from the line 5-5 of FIG. 4;
FIG. 6 is an exploded view in perspective of my novel step insert, and
FIG. 7 is a view in perspective showing my novel stepforming arrangement in operative position in a pipe section.
Referring with greater particularity to the drawings, a conventional pipe section is identified by the reference character A. As indicated in FIGS. 2 and 3, pipe section A is normally formed between spaced concentric inner and outer mold sections 10, 11, respectively, only portions of which are shown.
In the practice of my instant invention, a horizontally disposed elongated anchoring plate 12 is detachably secured to the inner mold section 10, in radially outwardly spaced relation thereto, by means of headed clamping bolts 13 extending through the side wall of the mold section and through threaded apertures 12a in the anchorsection A.
ing plate 12, whereby to become imbedded in said pipe It will be noted that the anchoring plate 12 has rigidly afiixed to opposite ends thereof, parallel generally radially extended cars 14. Bars 14, as shown, are box-like and define sockets 15 which open radially inwardly through the inner peripheral wall surface 16 of the pipe section A, as indicated at 17.
Adapted to cooperate with the anchoring plate 12, and the socket-forming ears 14 carried thereby, after removal of the inner and outer mold sections 10, 11, from the ipe section A, is a step-forming member, identified in its entirety by 18. As shown, step-forming member 18 includes a pair of laterally spaced horizontally disposed parallel arms 19, 20, which are rigidly connected together at their radially inner end portions by a tread-forming step 21, and at their intermediate portions by a vertically disposed cross-brace 22. The radially outer end portions of arms 19, 20, define arm elements 19a, 20a, one each of which is adapted to be slidably received in one of the sockets 15 defined by the ear elements 14, through the mouth-like opening 17 thereof. It will be noted that whereas the vertical dimensions of the arm elements 19a, 20a are such, with relation to the sockets 15 in which they are received, substantially no vertical movement is permitted therebetween. However, the transverse dimensions of the arm elements 19a, 20a are such with respect to said sockets 15 that limited lateral movement in a generally horizontal plane is permitted, for a purpose which will immediately be explained.
It will be observed that the ear elements 14 are each formed to define latch detents 23 which are formed in common side wall portions 14a. As shown, these detents 23 are intermediate the months 17 of the sockets 15 and the closed radially outer ends 24 thereof. Secured to common sides 19!), 20b, of the arm elements 19a, 20a, and projecting laterally therefrom, and positioned longitudinally thereon in a position to be received one each within one of said detents 23 when the arm elements 19a, 20a are fully received within their respective sockets 15, are latch dogs 25, 26. To bring about reception of said latch dogs 25, 26 within their respective latch detents 23, it is but necessary to move the arms 19, 20 laterally, from left to right, with respect to FIGS. 5 and 6. Thereafter, for the purpose of securely locking the tread-forming step member 18 in its operative relationship, it is but necessary to insert a shim element 27 intermediate the arm element 19a and the adjacent wall portion 14b of the ear 14 associated therewith. As shown, the shim 27 is of a thickness to positively limit lateral movement of the arm elements 19a, 20a, thereby locking the latch dogs 25, 26 within their respective latch detents 23. Frictional engagement of the shim 27 with the arm element 19a and the wall portion 14b prevent accidental removal thereof.
My invention has been thoroughly tested and found to be completely satisfactory for the accomplishment of the above objects; and while I have disclosed a preferred embodiment thereof, same may well be capable of modification without departure from the scope and spirit of the appended claim.
What is claimed is:
In a device of the class described,
(a) an elongated horizontally extended anchoring plate imbedded in the wall of a concrete pipe section in spaced relation to .the inner peripheral surface thereof,
(b) opposite end portions of said plate having aflixed thereto generally radially extending socket-forming ear elements which are adapted to open inwardly through said inner peripheral surface,
(c) a pair of laterally spaced arms rigidly secured together adjacent their radially inner ends by stepforming tread members and having radially outer end arm elements which are simultaneously receivable within the sockets defined by said ear elements,
(d) said arm elements being received within said sockets for limited lateral movements in a generally horizontal plane,
(e) a pair of laterally projecting latch dogs, one each on an intermediate portion of one each of said arm elements and receivable Within cooperating latch detents formed in the adjacent Walls of said sockets and receiving said latch dogs when said arm elements are fully received within said sockets, and
(f) shim means insertable in one of said sockets Whereby to detachably lock said latch dogs Within their cooperating latch detents, said shim means extending the length of said socket with a portion thereof ex tending outside of said socket to facilitate grasping.
References Cited by the Examiner 5 UNITED STATES PATENTS 846,995 3/1907 Greeley 52-184 890,573 6/1908 Phelan 18290 2,574,938 11/1951 Sinner 52704 2,785,842 3/1957 Phelps 52184 X 10 3,065,820 11/1962 Prizler 52704 X FRANK L. ABBOTT, Primary Examiner.
JOHN E. MURTAGH, Examiner.