GB2083160A - A man lid for a fluid container - Google Patents

Abstract

The invention provides a man lid having a single lever operated catch which has a two stage release whereby the lever 16 is movable from a first position in which the lid is closed to a second position in which the cover of the lid is raised slightly to perm it venting and in which a clasp 18 remains in engagement with an anchor member 68 so as to prevent the lid from bursting open. <IMAGE>

Description

SPECIFICATION A man lid for a fluid container The present invention relates to a man lid for a fluid container and has particular application to road and rail tankers for transporting liquids and gases.

Containers whether for storage or transport of fluids are provided with so called "man lids" which allow access into the container for inspection and/or maintenance and for filling of the container. A known man lid comprises an annular base plate which is secured to the container for example by welding or bolting, and which has an opening which is closable sealingly by a cover.

The cover is pivotally attached to the base plate and is provided with a plurality of swing bolts which are attached to the base plate and which engage with flanges provided in the cover. The swing bolts are spaced circumferentially around the cover. When it is required to open the cover each swing bolt is released gradually so that, if there is a pressure build-up within the container, the cover is permitted to lift, allowing the pressure to equalise, whilst the cover is retained, so preventing the lid from being force fully open by any pressure within the container.

A disadvantage of such a construction is that it is time consuming to release all the swing bolts gradually, and if the lid is opened by an unskilled operator which may not follow this procedure then if the swing bolts are completely released before the pressure is equalised an accident may result as the lid is likely to fly open.

It is an aim of the present invention to provide a man lid which can be released quickly compared with the known man lid and which will allow pressure equalisation during opening without risk of the lid bursting open.

According to a first aspect of the invention there is provided a man lid for a fluid container comprising a base plate which is adapted to be secured to the fluid container and which has an access opening therein which is closable sealingly by a cover member, the cover member being pivotally secured to the base plate, the base plate or cover member carrying a leverjournalled therein for pivotal movement with respect thereto and a clasp member carried by the lever and engageable releasably with an anchor member secured to the other of the cover member or base plate for fastening the cover in a closed position when the lever is in a first position, the lever being movable to a second position in which the cover member unseals the access opening whilst still in engagement with the anchor member, the lever being movable to a further position in which the clasp member disengages with the anchor member permitting further pivotal movement of the cover member to uncover the access opening.

Preferably the lever is secured to the cover member and the anchor member is secured to the base plate.

In one embodiment of the man lid the clasp member comprises a bar fixedly secured to the lever, which bar is received within an arcuate slot formed in the anchor member, the bar engaging releasably with a first notch in the arcuate slot when the lever is in its first position, and the bar engaging in a second notch in the arcuate slot when the lever is in its second position. A locking mechanism is preferably provided to lock the lever in its first position.

According to another aspect of the invention there is provided a man lid for a fluid container comprising a base plate which is adapted to be secured to the fluid container and which has an access opening therein which is closable sealingly by a cover member, the cover member is pivotally secured to the base plate, the base plate or the cover member carries a lever journalled therein for pivotal movement with respect thereto and a clasp is journalled in the lever, the clasp is engageable releasably with an anchor member fixedly attached to the other of the cover member or base plate for fastening the cover in a closed position when the lever is in a first position, the lever being movable to a second position in which the clasp remains engaged with the anchor pin whilst permitting pivotal movement of the cover sufficient to unseal the cover plate from the base plate, the lever being movable to a still further position in which the clasp is disengaged from the anchor member permitting further pivotal movement of the cover member to uncover the access opening.

According to a preferred embodiment of the invention a man lid for a fluid container comprises a base plate which is adapted to be secured to the fluid container and which has an access opening therein which is closable sealingly by a cover plate of a cover member, the cover member is pivotally secured to the base plate and carries a locking mechanism having a leverjournalled in the cover member fior pivotal movement with respect thereto and a clasp journalled about a spindle carried by the lever, the clasp is engageable releasably with an anchor member fixedly attached to the base plate for fastening the cover in a closed position when the lever is in a first position, the lever being movable to a second position in which the clasp remains engaged with the anchor pin whilst permitting movement of the cover sufficient to release the seal between the cover plate and the base plate, the lever being movable to a still further position in which the clasp is disengaged from the anchor member permitting further pivotal movement of the cover member to uncover the access opening.

Preferably a lock is disposed in the cover member and comprises a spring loaded plunger, one end of which is adapted to be received in an opening formed in the handle when the handle is in its first position. The plunger is displaceable by a reieasable key to permit movement of the lever from its first position.

Preferably the cover member comprises an inverted substantially U-shaped cross-bar and the cover plate is secured to the cover member by means of an adjustable locating strut and one or more adjustable spring members.

Preferably the lever is pivotally connected to the cross-bar by a pair of spigots which are secured to sides of the lever and pass through bores formed in the sides of the cross-bar. The spigots carry torsion springs which exert a restoring force between the cover member and the lever to displacethelever towards its second position when the locking mechanism is released. The lever also carries a clasp spindle upon which is journalled the clasp. Each end of the spindle is received in a bore the respective side of the lever and the spindle passes through an arcuate slot formed in the sides of the cross-bar. The spindle carries a further torsion spring whi-ch engages the cross-bar and the clasp biases the clasp towards the anchor member.

The present invention will now be described further, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a sectional view of a man lid in the closed position.

Figure 2 is a fragmentary sectional view of the man lid of Figure 1, in the partially released position; Figure 3 is a sectional view taken along the line A-A of Figure 1; Figure 4 is a part sectional view on section IV-IV of Figure 5 of a second embodiment in accordance with the invention; Figure 5 is an end view of the second embodiment looking in the direction of the arrow A, and Figure 6 is a perspective view of an alternative anchor member.

Referring to the drawings of Figures 1 to 3, a man lid is shown which comprises a cover member generally indicated as 2 which has a substantially inverted U-shaped cross-bar 3 which is pivotally secured to a base plate 6 by means of a spindle 4.

The cross-bar 3 carries a cover plate 8 which is adapted to close sealingly on opening 10 in the base plate 6. The base plate 6 is adapted to be attached to the fluid container by any convenient means for example by welding or by bolting. The cover plate 8 is secured to the cross bar 3 of the cover member 2 by way of an adjustable mounting bolt 12 and four spring members 14. The spring members bias the cover plate 8 away from the cross bar so that, when the cover is in its closed position, the cover plate contacts with a rim 15 of the opening 10 in the base plate 6.

The loading in the spring members may be adjusted by means of the adjustable mounting bolt 12 the purpose of which will be more fully under stood from the description of the operation outlined further herein below. The mounting bolt 12 also acts as an abutment for retaining the cover plate 8 when the cover is in its open position.

The man lid is provided with a pedal assembly which comprises a lever 16 and a clasp 18. Two spigot pins 20,22 act as the pivot for the lever and one spigot pin 20 is attached to one side 24 of the lever and the other spigot pin 22 to the other side 26 of the lever by means of threaded screws 28. The spigot pins 20, 22 pass through a respective bore 30, 32 formed in the sides 34, 36 of the cross-bar 3.

Each spigot pin carries a lever torsion spring 40 one end 44 of which engages a flange 42 on the lever and the other end 46 engages the cross-bar 3. The flange 42 extends beneath the cross-bar, and has a recess 43 within which the clasp 18 is movable. The flange 42 forms a cover to prevent damage and tampering of the lever and clasp mechanism. The lever torsion springs 40 act to bias the lever in a clockwise direction as viewed in Figure 1. The clasp 18 has a bush 50 which is journalled on a spindle 48 and which permits pivotal movement of the clasp with respect to the lever. The spindle is received in bores 52, 54 formed in the sides 24, 26 of the lever and is retained by set screws 56 and washers 58. The spindle 48 passes through an arcuate slot 59 formed in the sides of the cross-bar.A clasp torsion spring 60 is received on the bush 50 and one end 63 engages the cross-bar and the other end 65 engages the clasp so as to bias the clasp 18 in an anticlockwise direction as viewed in Figure 1.

The clasp 18 has a recess 66 which co-operates with an anchor member 68 fixedly attached to the base plate 6. As is in Figure 1 a locking mechanism 70 is provided which has a plunger 72 and a spring 74 which urges the plunger to the right as viewed in Figure 1, so that when the lever 16 is in the position shown in Figure 1 the plunger 72 is received in an aperture formed in a keeper plate 74. The keeper plate 74 forms part of the lever 16. A releasable key (not shown) operates the locking mechanism to release the plunger 72 from the aperture in the keeper plate.

The operation of the catch mechanism of the man lid is described below. For the purpose of the description it will be assumed that the man lid is closed and the clasp is engaged with the anchor member, the opening procedure is as follows. First the releasable key is inserted in a key hole of the locking mechanism 70 and turned to displace the plunger 72 out of the recess in the keeper plate 74.

The lever torsion spring 40 displaces the lever 16 in a clockwise direction and the keeper plate 74 is moved upwardly such that on release of the key the plunger can no longer engage the recess in the keeper plate.

The lever 16 is moved by this torsion spring in a clockwise direction to the position indicated in Figure 2. During this operation the recess 66 of the clasp 18 remains engaged with the anchor member 68, but since the lever 16 pivots about the axis of the pins 20,22 and the clasp 18 is attached by way of the spindle 48 to the lever, the clasp is itself rotated in a clockwise direction about the anchor member. Since the lever, clasp and cross-bar form with the base plate afour-barchain pivoting of the lever causes the cross-bar to be pivoted in an anti-clockwise direction about the pivot 4. The movement is sufficient to actually lift the cover plate 8 off its seating with the opening of the base plate 6 or to reduce the loading of the spring members to such a degree that the pressure within the tank lifts the cover plate. This action allows the pressure within the tank to be equalised with that outside. During this movement of the lever from a first position in which the cover is closed to the second position in which the pressure in the tank is vented, the clasp 18 remains engaged with anchor pin 68 and there is no danger of the lid bursting fully open. During the pivoting of the lever 16 from the first position to the second position the spindle 48 is displaced from one end of the arcuate slot 59 to an intermediate position. This intermediate position is shown in Figure 2.

Further movement of the lever 16 beyond the second position has to be performed manually and such movement results in the spindle 48 moving further in the arcuate slot 59 until it is at the end remote from the starting position. The clasp 18 is thus rotated still further and when in this end position, with the pressure on the cover released, the recess 66 in the clasp 18 is no longer retained by the anchor pin 68 and the clasp 18 is rotated in a clockwise direction or viewed in Figure 2 about the spindle 48 against the force of the torsion spring 60.

The cover may then be swung completely open to permit access to the container.

Closing of the cover is essentially a reverse of the opening procedure. The mechanism has the advantage that is is not possible to lock the lever 16 in its closed position if the clasp 18 is not engaged with the anchor member 68. This is made possible by the provision of a shoulder 80 on the clasp 18. If on closing, the clasp is in a position other than that shown in Figure 1,then the shoulder 80 will engage with a flange 82 of the cross-bar 3 preventing movement of the clasp and it will not be possible to displace the lever 16 into its locked position.

The resilient mounting of the cover plate 8 to the cross bar 3 serves as a safety device such that in the event of excessive pressure build-up within the container the spring members are compressed and the cover plate 8 lifts relieving the pressure. Such excessive pressure may arise as a result of fire engulfment.

Referring now to Figure 6there is shown an alternative anchor member which is intended to be used in place of the anchor member 68 described and illustrated with referenceto Figures 1 to3. It comprises a rod 100 secured between walls 102, 104 which are welded or otherwise attached to the base plate 6. A closure plate 106 is provided between the walls 102, 104 on one side of the rod 100 and an inwardly directed flange 110 is provided on each wall on the other side of the rod 100. An opening 108 is defined between the flanges 110 through which the clasp passes to permit engagement and disen gagementwith the rod 100. The modified anchor member is designed to be more tamper proof than that illustrated in Figures 1 to 3 so preventing the clasp being levered out of contact with the anchor member by external means.

Referring now to Figures 4 and 5 there is shown an alternative embodiment of the invention which utilises the two-stage opening of the first embodiment, but which is of simplified construction. The same reference numerals as used in Figures 1 to 3 will be used for identical parts. Only part of a man-lid is shown in Figure 4 and comprises a cover member 2 comprising a cross-bar 3, a cover plate 8 and a lever 16. Springs 14 are disposed between the cross-bar 3 and the cover plate 8 and act to bias the cover plate 8 towards the opening 10 in the base plate 6. The cross-bar 3 is pivotally secured to a base-plate 6 by means not shown but corresponding to the arrangement shown in Figure 1. The lever 6 is attached to the cross-bar 3 and is pivotable about an axis 21 corresponding to the axis of the spigot pins 22 in Figures 1 to 3.An anchor member 68 is secured to the base plate 6 and comprises a plate 112 having an arcuate slot 1 14 formed therein. First and second notches 116, are formed in an upper edge 120 of the slot. A locking bar or clasp 122 is adapted to be received in the slot and is secured fixedly to the lever 16 by mounting lugs 124.

When the lever is in its first position illustrated in Figure 4 corresponding to the closed position the locking bar 122 is received within the arcuate slot 114 and indeed is engaged with the first notch 116.

The resilience of the springs 14 in conjunction with the pressure in the container serves to bias the cross-bar upwardly so biasing the locking bar 122 into contact with the notch 116. When the lever is raised to its second position the locking bar is rotated in an anti-clockwise direction as viewed in the drawing, since it is fixed to the lever, and the springs and pressure in the container serve to bias it into contact with the upper edge 120 and hence it is urged to engage with the second notch 118. In this position the pressure exerted by the springs 14 is somewhat reduced so permitting the cover plate to lift and allowing venting of the container to occur.

The lever 16 may then be safely moved to its further position wherein the locking bar is disengaged from the arcuate slot 114 to allow the cover member to be opened fully. Thus it will be seen that this embodiment provides a simplified version of the two stage opening which ensures that the man-lid can be opened safely without fear of it bursting open.

The man lids described would be provided with a vent which would serve to equalise small pressure variations between the interior and exterior of the container either positive or negative which occur as a result of ambient pressure or temperature changes. The vent incorporates balls which seal off the vent openings to prevent spillage of the container if overturned.

Whilst the invention has been described with reference to an embodiment in which the lever and clasp are pivotally secured to the cover it is equally possible for the lever to be pivotally connected to the base plate, and for the clasp of the lever to engage with an anchor point on the cover.

The present invention has the advantage that the pre-closing and final locking and interlocking action is achieved through the one clasp and handle (16, 18) and shoulder (80).

Claims (15)

1. A man lid for a fluid container comprising a base plate which is adapted to be secured to the fluid container and which has an access opening therein which is closable sealingly by a cover member, the cover member being pivotally secured to the base plate, the base plate or cover member carrying a lever journalled therein for pivotal movement with respect thereto and a clasp member carried by the lever and engageable releasably with an anchor member secured to the other of the cover member or base plate for fastening the cover in a closed position when the lever is in a first position, the lever being movable to a second position in which the cover member unseals the access opening whilst still in engagement with the anchor member, the lever being movable to a further position in which the clasp member disengages with the anchor member permitting further pivotal movement of the cover member to uncover the access opening.

2. A man lid as claimed in claim 1 in which the lever is secured to the cover member and the anchor member is secured to the base plate.

3. A man lid as claimed in claim 1 or 2 in which the clasp member comprises a bar fixedly secured to the lever, which bar is received within an arcuate slot formed in the anchor member, the bar engaging releasably with a first notch in the arcuate slot when the lever is in its first position, and the bar engaging in a second notch in the arcuate slot when the lever is in its second position.

4. A man lid as claimed in claim 1 or 2 in which the clasp is journalled in the lever for pivotal movement with respect thereto and is engageable with the anchor member when the lever is in its first position and the cover closed, which clasp remains engaged with the anchor member when the lever is moved to its second position whilst allowing pivotal movement of the cover member sufficient to unseal the cover member from the access opening.

5. A man lid as claimed in any preceding claim in which a locking mechanism is provided to secure the lever in its first position.

6. A man lid as claimed in any preceding claim in which the cover member comprises a cross-bar which carries the lever and which is pivotally secured to the base plate, and a cover plate which serves to coverthe access opening and which is coupled to the cross-bar by an adjustable length strut under the influence of at least one spring member.

7. A man lid as claimed in claim 6 in which a pair of spigots having a common axis are secured to the lever, which spigots pass through a respective bore formed in the cross-bar and serve to form the pivotal connection between the lever and the cover member.

8. A man lid as claimed in any of the preceding claims when dependent on claim 5 in which torsion springs are carried by the spigots, which springs bias the lever from its first position towards it second position on release of the locking mechanism.

9. A man lid as claimed in any of claims 5 to 8 in which the locking mechanism comprises a spring loaded plunger carried by the cover member, one end of which plunger is adapted to be received in an opening in the lever when in its first position.

10. A man lid as claimed in claim 9 in which the plunger is retractable by a releasable key to permit movement of the lever from its first position under the influence of springs.

11. A man lid as claimed in any of claims 6 to 10 in which a spindle mounted in the lever carrying the clasp, passes through and is arranged for movement in an arcuate aperture in the cross-bar of the cover member upon movement of the lever between at least its first and second positions.

12. A man lid as claimed in claim 11 in which the spindle carries a further torsion spring which takes its abutment between the clasp and the cover member to bias the clasp in a direction towards the anchor member.

13. A man lid constructed and arranged and adapted to operate substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings of Figures 1 to 3.

14. A man lid constructed and arranged and adapted to operate substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings of Figures 4 and 5.

15. A man lid constructed and arranged and adapted to operate substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings of Figures 1 to 3 as modified by Figure 6.