AU735571B2 - Roadway manhole cover hinged to a frame - Google Patents

Description

0.0..

100.

o

AUSTRALIA

Patents Act 1990

NORINCO

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT Invention Title: Roadway manhole cover hinged to a frame The following statement is a full description of this invention including the best method of performing it known to us:- The invention is aimed mainly at roadway manholes and similar, and in essence consists of a frame which is recessed into and level with the roadway, and onto which is mounted a hinged cover.

There are many types of manhole cover already available, and these include types with a quadrilateral type of frame to which are attached complementary triangular plates of right-angle triangle shape forming a cover for closure of the opening which is formed by the frame. In the case of such known triangular-shaped manhole covers, the plates are generally heavy and difficult to lift, and in addition, are hinged on two opposite sides of the frame, making access to the frame awkward if not difficult, that is for the introduction of equipment such as piping of cables, where the aperture in the roadway is bounded by the frame.

Furthermore, this invention is intended to remedy these disadvantages by providing a manhole where opening and closure of the manhole cover is particularly easy, and which, when in the open position, provides easy and immediate access through the frame to the tunnel or the manhole in the **roadway, with no hindrance from the open cover.

According to the invention there is provided a roadway manhole cover comprising a quadrilateral-shaped frame and a plug selectively adopting a S 20 closed position and an open position in which said plug respectively closes and opens the frame, said plug comprising at least a first pair of triangular cover plates respectively hinged onto first and second adjacent edges of the frame so as to allow a free access, in the open position of the plug, to at least a third edge of the frame, and each cover plate having a free apex, characterised 25 in that the cover plates of each pair have the shape of right-angle triangles and are directly juxtaposed by their hypotenuse in the closed position of the plug, and in that the free apices of all the cover plates are mutually adjacent.

As can readily be seen, free access to the frame will be clearly facilitated by the fact that two adjacent sides of the frame will be left clear of hinged cover plates.

According to a second aspect, the manhole cover of this invention includes two triangular cover plates which are hinged by one of their short sides on two adjacent sides of the frame.

According to another method of manufacture, this manhole cover consists of four triangular plates, in the form of two plates hinged open one of their short sides on two opposite sides of the frame, and another two plates hinged on their short sides, side by side to one of the other sides of the frame.

go *ee* eeoc* eeee gee..

According to yet another version of the invention, each triangular plate hinged to the frame, except one, is fitted with at least one projecting lug which fits into the underside of an adjacent plate.

A further feature of the above is that the triangular plate which is not fitted with the mentioned lug is fitted with a system for locking this plate to the frame.

As can be seen from the foregoing, the existence of these lugs, locking the single plate bearing no lug will lock all of the other plates.

However the invention has other advantages and characteristics which are more readily appreciated in the detailed description which follows, and which refers also to drawings in the appendices which are supplied for the purpose of illustration only, and in which: figure 1 is a plan view (from above) of a frame with a cover composed of two triangular plates as per this invention, shown in the closed position.

Figure 2 is a very schematic view in perspective of the roadway manhole cover of figure 1, but S.:i shown in the open position.

Figure 3 is a plan view (from above) of a roadway manhole cover with a cover composed of four triangular plates, in an alternative design.

Figure 4 is a very schematic view, in perspective, showing the manhole cover of figure 3, in the open position.

S Figures 5 and 6 comprise a view in partial section of the hinging of a cover plate on the frame, this hinging being illustrated in the closed position of the cover in figure 5 and in its closed position in figure 6.

•i figures 7 and 8 represent two views in section of the lock associated with one of the cover plates, in the locked and unlocked positions respectively.

Referring to the figures, we see a frame designed to outline an opening made in a roadway, for example, this frame being of quadrilateral shape, and onto which are hinged complementary triangular plates of right-angle triangle form to constitute the cover closing off the frame According to the design in figures 1 and 2, onto this frame are hinged two triangular plates (2 and 3) of right-angle triangle shape, which lie adjacent to each other along their hypotenuses (4) when closed.

According to a further essential characteristic of the invention, the two plates (2 and 3) are hinged on two adjacent sides (la and lb) of the frame. More accurately, plate 2 is attached by two hinges (2a) to side l a of frame 1, and plate 3 is attached by two hinges (3a) to side lb of frame 1, which is adjacent to side la.

As can be seen clearly from figure 2, when triangular plates 2 and 3 are open, very easy access is provided to the manhole or tunnel, since adjacent sides Ic and id will be left conveniently clear.

It can also be seen on figure 2 that one of the triangular plates, namely plate 2 in the example shown, has a lug projecting from this plate and designed to lie below the underside, that is face 3c, of plate 3, which is also fitted with lock 6, clearly illustrated in figures 7 and 8, and which is used to lock this plate onto the frame It can therefore be seen, by referring to the open position of the manhole cover as shown in figure 2, that the cover is closed by first lowering plate 2 onto frame 1, and then plate 3 which bears onto lug 5 of plate 2 which will lock the latter, after which operation of lock 6 on plate 3 will finally lock the cover composed of plates 2 and 3 onto frame 1. It can be seen that plate 3 does S 15 not have any projecting stud •°In the design illustrated by figures 3 and 4, frame 1 is a single-piece frame created by casting (as was frame 1 in the design described above), comes in a more rectangular shape than the squarish shape of the first example.

.**Onto frame 1 in this case are hinged four triangular plates (10, 11, 12 and 13) on three adjacent sides (ld, la and Ib) of frame 1.

More accurately, plates 10 and 13 are attached respectively by hinges 10a and 13a, and by one of their short sides, to two opposite sides (id and Ib) of frame 1. These two sides (Id and Ib) are the short sides of the rectangle forming frame 1.

The other two plates (11 and 12) are attached respectively by hinges I la and 12a, by their other short side to one of the two remaining and opposite sides (la or Ic) of frame 1. Sides la and Ic are the long sides of the triangular frame.

It can be seen clearly in figure 3 that plates 10 and 11 lie alongside each other along their hypotenuses and that plates 12 and 13 likewise lie together along their hypotenuses while plates 11 and 12, hinged to the same side of frame 1, lie alongside each other also along short side 16.

As can be seen on figure 4, plates 10, 11 and 12 are each fitted with a projecting lug while plate 13, which has no such lugs, is fitted with a lock Thus on the same principle as that explained earlier for figures 1 and 2, starting from the open position on figure 4, to close the manhole cover which has just been described, plates 10, 11 and 12 are closed in that order, and these self-lock by means of the lugs Plate 13 is closed finally and is locked onto frame 1, thereby also locking plates 10, 11 and 12. Thus the manhole cover is closed by successive lowering of plates 10, 11, 12 and 13 in an anti-clockwise manner, and the cover is opened in a reverse manner, lifting plate 13 first, and then opening plates 12, 11 and in that order.

In this respect, it can be seen that opening of the plates successively in one order and closure of the plate in the reverse order will have the advantage of facilitating the work of even an untrained o• field operative faced with the problem of raising several cover plates.

Returning to figure 4, it can be seen that in the open position, considerable clearance is made available along the long side (Ic) of the rectangular frame, so that access to the manhole or the S 15 tunnel, and introduction of equipment through the frame, will be particularly easy and rapid.

Hinging of the triangular plates, in the shape of right-angle triangles, into frame 1, whether it concerns the plates in the version of figure 1 or the variant of figure 2, is of a type which is known as such, and will be described briefly with reference to figures 5 and 6.

0 Each plate, such as plate 2 for example, is fitted with an ear or similar (20) which accepts a pin (21) attached to frame 1. Ear 20 has a beak (22) which, in the open position of plate 2 (figure 6) can fit into a cut-out or similar (23) in frame 1.

Thus starting from the closed position of plate 2 as shown in figure 5, the plate is opened by pivoting it in the direction of the arrow whereupon beak 22 lodges in cut-out 23, holding plate 2 positively in the open position.

To close plate 2, slightly lifting the later releases beak 2 from cut-out 23, and it will then fold against the frame moving the direction opposite to that of arrow F. The feet or similar of plate 2 have been shown already, allowing this plate to rest on frame 1 in the closed position.

The locking system associated with the only cover plate of frame I which is not fitted with lug that is plate 3 as shown in figures 1 and 2, or plate 13 as shown in figures 3 and 4, will also be described in a concise manner.

In figures 7 and 8, it can bee seen that lock 6 associated with the aforementioned plate, plate 3 for example, is composed in essence of a rotor (30) mounted to rotate on plate 3, and held by a spring This rotor (30) is associated with a bolt or similar (32) which is designed to fit into a rib (33) on frame 1.

starting from the locked position shown in figure 7, a key (34) is used to turn rotor 30 through a quarter turn for example, to draw bolt 32 clear of frame 2, thus releasing plate 3, as can be seen clearly in figure 8.

Of course the invention is not limited to the methods of manufacture described and illustrated, as these have been given as an example only.

In this manner, triangular plates in the shape of right-angle triangles can be used in numbers other than those described, on condition that these plates are hinged to certain adjacent sides of the frame, so that the other side or sides of the frame are left clear in the open position.

This invention therefore covers all equivalent techniques associated with the system described, •and their combination, as long as these are included in the following claims.

S.

.:•ooi

Claims (4)

1. A roadway manhole cover comprising a quadrilateral-shaped frame and a plug selectively adopting a closed position and an open position in which said plug respectively closes and opens the frame, said plug comprising at least a first pair of triangular cover plates respectively hinged onto first and second adjacent edges of the frame so as to allow a free access, in the open position of the plug, to at least a third edge of the frame, and each cover plate having a free apex, characterised in that the cover plates of each pair have the shape of right-angle triangles and are directly juxtaposed by their hypotenuse in the closed position of the plug, and in that the free apices of all the cover plates are mutually adjacent.

2. A roadway manhole cover as claimed in claim 1, characterised in that the plug comprises a second pair of triangular cover plates respectively hinged onto the first edge and onto a fourth adjacent edge of the frame, and in that the first and second pairs of cover plates have respective adjacent cover plates which are juxtaposed by one of their right edges in the closed position of the plug.

3. A roadway manhole cover as claimed in claim 1 or 2, characterised in that each triangular plate hinged to the frame except one is fitted with at least S 20 one projecting lug which lies against the underside of an adjacent plate.

4. A roadway manhole cover as claimed in claim 3, characterised in that the triangular plate which is not fitted with the above mentioned lug(s) is fitted with a locking system for locking this plate onto the frame. A roadway manhole cover substantially as hereinbefore described with 25 reference to the accompanying drawings. oo Dated this eighth day of May 2001 Norinco Patent Attorneys for the Applicant: F B RICE CO