US2783913A

US2783913A - Manhole cover attaching means

Info

Publication number: US2783913A
Application number: US366848A
Authority: US
Inventors: Frees Joseph H De
Original assignee: ANNE DE FREES
Current assignee: ANNE DE FREES
Priority date: 1953-07-08
Filing date: 1953-07-08
Publication date: 1957-03-05
Anticipated expiration: 1974-03-05

Description

J. H. DE FREES 2,783,913

. MANHOLE COVER ATTACHING MEANS March 5, 1957 2 Sheets-Sheet 1 Filed July 8. 1953 INVENTOR. V559 H Defksss March 5, 1957 J DE FREES 2,783,913

MANHOLE COVER ATTACHING MEANS Filed July 8, 1953' 2 Sheets-Sheet 2 INVENTOR. JIOJEPH hi DEF/F656 A TTdRA/E'YJ United. States, Patent l e MANHOLE COVER ATTACHING Joseph H. De Frees, Warren, 2a., assignor to Anne De Frees, Warren, Pa.

Pl a J .8, 9 3 Ser a area 1 Claim. (Cl. 220-46) This invention relates to safety tank closures, and particularly to novel and improved clamping means for'attachingsuch closure to the tank shell. A

An object of the invention is to provide novel clamping means which is light in weight and exceptionally easyto remove.

A further object of the invention is to provide closure means including novel clamping means which allows rapid removal of the closure, giving clear and unobstructed access to the interior, and avoids the necessity of wrench manipulation within the tank, a disadvantage inherent in many former closures of this general type. As is known to those skilled in this art, the careless or vigorous use of a wrench inside a tank which may be filled with inflammable or explosive vapors is a potent source of accidents from sparking.

A further object of the invention is to provide in combination, closure means for a tank, and clamping means therefor, of such character that the opening to the tank interior is free from bothersome obstructions, such as wing nuts, springs, bolt ends, or other necessary adjuncts of former structure, which have interfered with the normal uses of the fill opening, when opened.

Other objects and advantages will be apparent from a study of the present specification, in conjunction with the accompanying drawings, showing one embodiment of the invention, in which:

Fig. 1 is a top plan view of a manhole cover closure, with clamping means thereon in accordance with my invention.

Fig. 2 is a view, greatly enlarged, taken on the line 2--2 of Fig. 1.

Fig. 3 is a vertical sectional view taken on the line 3-3 of Fig. 1.

Fig. 4 is a vertical sectional view taken on the line 4--4 of Fig. 3.

Fig. 5 is a top plan view and Fig. 6 is a bottom plan view of the vent valve shown in Fig. 4.

Referring now to the drawings I show a fragmentary portion of the upper wall of a storage or transportation tank 10 formed from sheet metal. This wall is provided, as is usual, with a manhole defined by an annular neck 11, also of sheet metal, which is welded or otherwise suitably attached to top wall 10 in leak-proof fashion. This annular neck has an outturned flange 12 around its upper periphery, said flange being preferably in a flat plane since it serves as a seat member, as will appear. A cover plate 13 is provided to seal the manhole opening, and allow for automatic venting in both directions. The present inven tion of course resides in the means for ready removal of the cover plate 13 and associated mechanical elements. Such elements include means for supporting a venting unit, said means comprising a cross bar 14 hinged at 15 on a lug 16 attached to cover 13. The cross bar carries the vent housing 17 which has a threaded connection with a boss 18 on the cross bar. The vent housing carries a discoidal plate 19, a circular gasket 20 of sealing material and a 2,783,913 Patented Mar. 1957 2 retainingplate 21, the purpose of which assembly is to normally seal a filling opening 22 in plate 13.

The function and operation of this filler sealvand vent device is as follows. Within housing 17, and retained by cap 25 'is a mesh screen 26 supporting a light spring 27 which maintains on its top a ball valve unit. This unit comprises two nested cups 2-8 and 29, cup'29 beingfixed'in housing 25 by means of arms 29a. Cup 29 carries a ball 30 normallydownwardly seating by gravity in the neck 29a. Cup 28-carries a ball 31' normally lying inactively in its cup bottom, but adapted to seal theaperture 32 if the tank'rolls upside down.

Any vapor pressure within the tank passes through screen'2 6 andneck 29a andraisesballfiil. It then passes between cups '28 and 29, and through apertures 33 (of which there are four) in the wall of cup'28, thereafter escaping through aperture 32. Should the pressure within the tan'ksuddenly drop by reason ofdumpingor discharge of liquid from thetank, the base plate 34will compress spring 27 thereby'permitting 'immediate pressure equalization. If the tank is involved in an accident so as to be overturned, ball 31 will drop and seal aperture 32 so as to prevent liquid escape.

When clamped as shown, and soon to be described, plate 19 is normally immovably sealed. If unexpectedly heavy pressure suddenly develops within the tank, for example in case of fire, the strength and flexibility of plate 19 are so controlled and designed that said plate will deflect at any pressure in excess of a predetermined amount, for example three to four pounds per square inch, and thus plate 19 serves as a giant pop valve. If, as hereinabove mentioned, the tank overturns, plate 19 is sufficiently firmly clamped to retain the static head of the liquid load, and only an excessive pressure arising from rapid combustion will be relieved by flexure of plate 19.

The cross bar 14 is locked in place by a lock lever 35 pivoted at 36 on a lug 37 attached to cover plate 13. Lever 35 has an opening 33 through which the tongue 14a of lever 14 extends when the parts are in closed position, and levers 35 and 14 have cooperating shoulders which snap into retaining abutment and maintain peripheral edge contact around the edge of the filling aperture 22.

It will be apparent that for normal service use, involving mostly the filling of the tank, the opening operation, first of the lock lever 35 and then the cross bar 14, lifts the venting unit and the associated discs 19, 2t), and 21.

For internal service of any kind it is desirable to remove the whole top plate 13, which is usually retained securely in place in the following way.

Referring particularly to Figs. 1 and 2, the peripheral flange 12 of neck 11 has an annular gasket 40 of U-shaped transverse section snapped thereon. The gasket is formed from resilient, rubber-like material and has lateral edge beads 40a and 401) which serve as strengthening retainers, and the bead 40a takes the sealing pressure, as will appear, because cover plate 13 rests on bead 40a.

For securely clamping plate 13 and flange 12 together I provide a split clamping ring 43 of channeled contour in section, which is here shown as irregular U-contour in section. At the split each end is provided with clips or

blocks

43a and 43b which are tunneled to receive the shank of a bolt 44, retained by a clamping nut 45. Slacking off the nut 45 permits ready removal of ring 43 which is actually biased to spring open suiiiciently to permit its removal from the plate 13 and flange 12.

In prior constructions the main cover plate, corresponding to present member 13, was usually attached by internal bolts, and removal of such plate necessitated removal of a number of bolts, usually six in number, which was a time-consuming activity and manipulation of tools on the inner surface of the tank top could well result in striking sparks from the ferrous metal portions of the structure, which would be most serious in the presence of certain airvapor mixtures. With my invention the attaching and detaching operations are performed while the cover plate 13 is resting on gasket 40, so as to minimize explosion dangers, or subjection of workmen to noxious fumes.

In the present embodiment the

clips

43a and 43b are simple pieces of sheet metal, bent to the shape shown in Fig. 2, and welded in place. The ring 43 is also shaped from sheet metal. Any channeled contour, opening inwardly, which suits the arrangement of the parts to be clamped, will be quite adequate, provided its shape is such as to exert a wedged grip on the flange 12 and the edge of plate 13 when the clamp is tightened.

. What I claim is: I H

Closure and clamping means for a manhole aperture in a tank comprising a peripheral outturned flange fixed around said aperture in a horizontal plane, a closure member overlying said flange and having a circumferential horizontal rim portion also in a horizontal plane, said flange and said rim portion having registered peripheral edge portions, an annular gasket of ruhbcrlike material and of U-shaped sectional contour peripherally embracing said flange edge portion in such manner that one of the legs of the U-shaped gasket lies between said flange and said rim portion, and the other leg lies below said flange, a split ring member of channeled contour opening inwardly and gripping said edge portions, one leg of said channel having a substantially planar surface which lies above said rim and contacts the same, and the other leg of said channel extending downwardly and inwardly and having an inner surface extending at an acute angle to the first said planar surface, said inner surface contacting a peripheral outer portion of said gasket, and cooperating means on each end of said ring on each side of said split for drawing said ends together to maintain said grip.

References Cited in the file of this patent UNITED STATES PATENTS 1,449,940 Hackney Mar. 27, 1923 1,640,430 Stanley Aug. 30, 1927 1,754,776 Stanley Apr. 15, 1930 1,904,09l Shoop Apr. 18, 1933 1,969,120 Coackley Aug. 7, 1934 2,226,396 Wackman Dec. 24, 1940 2,486,565 Kojan et a1 Nov. 1, 1949 2,633,616 Kohout Apr. 7, 1953