US 1793038 A
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Description (OCR text may contain errors)
Feb. 17, 1931. L. G. ZIMMERMANN 1,793,038
MANHOLE CONSTRUCTION Filed March 7, 1928 2 Sheets-Sheet l LIT gull Z6 I A,
BYQZKVKW M M M21 221 A TTORNEYS.
Feb. 17, 1931. G. ZIMMERMANN 1,793,038
MANHOLE CONSTRUCTION Filed March 7, 1928 2 Sheets-Sheet 2 INVEN TOR.
- A TTORNEYS Patented Feb. 17, 1931 PATENT OFFICE LEROY G. ZIMMERMANN, OF MILWAUKEE, WISCONSIN V MANHOLE CONSTRUCTION Application filed March 7,
This invention relates to improvements in manhole constructions.
It is the object of the invention to provide a manhole casing adapted for factory manufacture and assembly and standardized units in the location and to the required depth of manhole.
Further objects of the invention relate to a novel top section unit adapted to receive a standard cover, and to a floating cover ring mounted on such unit and provided with centering means whereby it need not be secured to the aforesaid top manhole unit and may be heaved by frost independently of such unit without disturbing the proper relation of the parts.
In the drawings Figure 1 is a side elevation in perspective of a device embodying this invention, fragments thereof being broken away;
Figure 2 is a detail View in vertical section' of the upper end of a casing device embodying this invention Figure 3 is a detail in transverse section taken in the plane indicated in 3-3 in Fig. 1;
Figure 4 is a side elevation of the bottom of the device;
Figure 5 is a detail view in plan of a fragment of one of the steps;
Figure 6 is a view of the step in transverse vertical section;
Figure 7 is a plan view of the device shown in Fig. 1;
Figure 8 is a section in the plane indicated at 8-8 in Figure 1.
Like parts are identified by similar reference numerals throughout the several views.
Only three principal types of castings are used to construct manhole casings in accordance with this invention. The fact that the number is limited to three effects great economies in manufacture and enables production methods to be employed for the first time in this industry.
The base section 10 is provided upon two 1928. Serial No. 259,890.
diameters with downwardly opening notches in its opposite margins, as shown at 11 and 12. Notches 11 are semicircular and of relatively large dimensions to take pipe of the relative size indicated at 13. Notches 12 are relatively smaller to receive pipes 14 which are laterals or delivery pipes or may comprise the main. It is intended, however, that pipe 13 shall represent the trunk line sewer and pipe 14 the laterals.
Upon the base 10 are assembled the annular sections 15 in vertical series to any desired height. The base section 10 at each of the intermediate sections 15 is provided with a belled top flange 16 into which the bottom margin of the next succeeding section is receivable, the joint being filled with cement, as at 17 It is obvious that a completely tight casing will result.
At the top of the series of intermediate sections 15, I employ an upwardly tapering top section 21 which is so formed as to eX- tend almost vertically at the side 22 and to have a pronouncedly inclined wall at 18. The vertical wall at 22 makes the ladder, hereinafter to be described, more readily accessible. The cover ring 19 has wedge-shaped centering lugs 20 at intervals about its under surface, such lugs being so disposed as to fit about the open mouth of the top section 21 to position or center the finishing plate 19 with respect to the opening.
In order that branch pipes or laterals may be introduced at a variety of angles to the interior of the manhole casing at any desired elevation, it is preferred to provide each of the several intermediate sections 15 of the casing with potential openings through which the lateral drains may extend. To this end each such intermediate section is provided at a plurality of points (preferably 4.) with round areas 25 of reduced thickness, such areas being bounded by beads 26 of increased thickness. As a result of this construction, it is readily possible to hammer or chisel out 90 the cast iron area of reduced thickness thereb lGELVlII an 0 enin of a sue to receive a b D lateral pipe. The fact that each section is rovided with a number of such potential P l openings and that thereare a number of secceive the correspondingly tapered pin portions 29 of the steps 30. The sections 15 will be so assembled that the lugs QS t-hereof will be in vertical alignment whereby complete ladder may be formed by the simple expedient of inserting the several step elements into their respective lugs insuperposed relation.
In constructing amanhole casing embodying this invention, the bottom section 10 is laid upon the completed length of pipe 13 which extends therebeneath. The .pipe will be received into the notchesll and 12, ac-
cording to the angular position of the manhole, and, as above indicated, is preferably received into notches 11. The bottom section is thus so positioned as to straddle the pipe.
Concrete mix will now be poured around the pipe within and about the bottom section 10 of the manhole casing. The concrete will fill'the bottom of the excavation at least to a depth sufficient to reach the lower margin of the section 10. This will imlced approximately half of the pipe 13 in the concrete foundation. Thereafter, at any subsequent time, the top of pipe 13 is broken in bya sledge or with a chiselto provide an opening 300 for communication between the'in terior of the manhole and the interior of the pipe. f
The several sections 15 are now laid up, one upon another, the joints between them being cemented, as above indicated, and at the proper point the top section 22 is set in place. In laying up the sections 15 the weakened areas will be broken out and lateral drains introduced as may be required. The excavation about the manhole casing is now filled with earth and the finishing ring '19 is laid to cover the upper margin of the top 22 and to receive the manhole cover 32. One of the difficulties heretofore experienced in the use of top plates or finishing plates has been the fact that they afforded a horizontal surface against which the surrounding earth could exert pressure in expanding or heaving under the influence of frost. With a top plate manufactured in accordance with this invention, no difficulty is experienced due to the fact that the top plate is floating and selfcentering so that when the earth again contracts, the top plate will settle back into a properly centered position at the upper margin of section 21 of the manholecasing.
It will be observed that the majority of the parts entering into the construction of this ever, that so far as oversized laterals are concerned it is possible if desired to divide the lateral and bring it into the manhole casing through two or more of the openings already provided for. r
It is possible, therefore, to manufacture cast iron manhole casings by production methods at prices sufliciently low to compete withjthe inferiorv masonry constructions" heretofore employed. g
It will be understood, of course, that the shape of such casings is not specifically material. will necessarily be annular in the sense that eachunit will comprise a closed geometrical figure whenviewed in plan, or in other words, will have a continuous peripheral wall. This does not mean, however, that the casing must necessarily be round as illustrated although the round construction is to be preferred be cause of-convenience and economy, Neither is it essential that the individual sections should maintain the illustrated ratio of diameter to axial extent, but hereagain it is preferred that the sectionsshould be relatively fiat in order that they may not be too weighty and difficult to manufacture and handle. The diameter is preferably relatively large to give the desired size of manhole, while the axial extent is small in order that the units may convenientlybe assembled with small increments of change to any desired structural height in order to meet exist- Each unit entering into the casing ing requirements at the place of installation. 7
I claim: 1. In a device of the character. described, the combination with a casing member having a well defined upper margin, of an overformed to center said plate with reference to said inarginupon the occurrence of relasaid plate having radially disposed lugs nor-.
mally supporting its overhanging portion from the tapering surface of said member and adapted to center said plate with respect to said member upon the occurrence of relative vertical movement with respect thereto.
LEROY G. ZIMMERMANN.