GB2221262A

GB2221262A - Improvements in or relating to sealing

Info

Publication number: GB2221262A
Application number: GB8817770A
Authority: GB
Inventors: John Wayne
Original assignee: Individual
Current assignee: Individual
Priority date: 1988-07-26
Filing date: 1988-07-26
Publication date: 1990-01-31
Anticipated expiration: 2008-07-26
Also published as: GB2221262B; GB8817770D0

Abstract

A sealing arrangement for a sump includes a bolt 10, a seal 12, a washer 14 and a nut 16. The four components are assembled prior to insertion into an opening. The effect of tightening the nut causes the tapered head of the bolt 10 to be partially drawn through the seal. This causes the seal to expand outwards with the result that three sealing points are made by the one single action. Firstly, the tapered head 18 creates a seal with the seal ring, internally. Secondly, the lip 30 of the seal hub is pressed over the internal surface 38 of the sump, evenly around the sump hole, creating an internal seal. Thirdly, the base section 28 of the seal, contained by the washer, compresses against the outer surface 24 of the sump, evenly around the sump hole, providing an external seal. <IMAGE>

Description

IMPROVEMENTS IN OR RELATING TO SEALING.

The present invention relates to a sealing arrangement and to a method of sealing an opening and Is particularly, although not exclusively applicable to a sump sealing arrangement and to a method of sealing an opening in a sump.

The most obvious application is as a sump plug In an internal combustlon engine, in which lubricating oil is contained within a sump below the working parts of the engine. Every ten thousand miles or so the oil in the sump becomes contaminated with metal worn from the engine. In addition, the oil, itself, tends to break down over this period of time due to exposure to the hot surfaces of the engine. Therefore, the existing oil has to be replaced with fresh oil. This is achieved by removing a plug from the sump and allowing the oil to drain from the engine. When draining is complete, the plug is replaced and new oil is added to the top of the engine, which falls to the sump under the action of gravity. The sump plug commonly in use has a number of disadvantages.In particular, it can be over-tightened, causing difficulty when it has next to be removed or stripping of the threads; it can be under-tightened, allowing leakage of oil around the threads of the plug or even the loss of the plug itself. Furthermore, the sump itself has to be threaded in order for the plug to be screwed into it. These difficultles can, in themselves, lead to additional costs in time, due to the effort required to remove over-tightened plugs, and in material, particularly oil, which causes other difficulties of fouling roadways, if the plug is under-tightened.

The same general problem can apply to tanks containing water or other chemicals, where plugs are used In preference to drain valves.

According to one aspect of the present Invention, In a sealing arrangement arranged to seal an opening, the arrangement comprises a flexible sealing member capable of being Inserted at least partially Into an opening, and an operating member extending at least partially through the sealing member, the sealing member and the operating member being arranged to co-operate such that relative translational movement between the members In one direction Is arranged to cause the sealing member to be urged outwardly In a direction transverse to the direction of relative movement.

The sealing member may be arranged to extend through an opening and the sealing member may be arranged to be inserted through one side of an opening and to seal with the other side of an opening. The sealing member may also be arranged to seal with the surface defining the side of the opening through which the sealing member is inserted.

Relative translational movement between the members In the one direction may be arranged to urge the members into sealIng engagement with each other.

The operating member may be arranged to be threadably engaged by a control member. Relative movement between the screw threads of the co-operating member and sealing members may be arranged to cause relative translational movement between the operating member and the sealing member.

The sealing member may Include an enlarged portion of generally the same cross-section as the opening which It is to seal wlth.

The arrangement may Include means for I imiting the extent of relative translatlonal movement between the operating member and the sealIng member In one direction.

Said means may comprise surfaces on the operating member and control member arranged to abut each other in a limiting position.

The operating member and the sealing member may co-operate to Inhibit relative rotational movement between those members.

According to another aspect of the present invention a method of sealing an opening comprises inserting a flexible member and an operating member at least partially through the opening from one side thereof and causing relative translational movement between the members in the direction through the opening to cause the sealing member to be urged outwardly In a direction transverse to the direction of relative translatlonal movement to seal with the opening.

The sealing member may be urged outwardly by the relative translational movement between the members to seal with a surface defining the opposite side of the opening from that which the sealing member is Inserted from.

The method may comprise limiting the extent of relative translational movement between the members. The relative translational movement may be I Imi ted by abutment of a control member with the operating member.

The control member may threadably engage with the operating member and relative movement between the Co- operating screw threads may be arranged to cause the relative translational movement between the operating member and the sealing member.

The method may also comprise forming a seal between the surface defining the opening from the side of the opening from which the sealing member Is Inserted and the sealing member.

The operating member may extend at least partially through the sealing member when the operating member and the sealing member are inserted through the opening.

The plug detailed in this patent application differs from those currently in use because It is specifically designed to provide a tight and effective seal to prevent liquid loss; the seal would be effective if the nut was only finger-tight; the nut is specifically devised, however, to ensure that it will be tightened by the correct amount, thus preventing over-tightening and avoidlng under-tightening. As a result, considerable savings will occur during normal maintenance operatlons, because troublesome removal of Jammed plugs will be eliminated. Furthermore, unnecessary oil, water or other chemical leakage will be reduced and probably ellminated during normal operations.

The actual size of the new plug is immaterlal, being dependent upon the actual appi ication. For one particular plug, however, the relative size of each of the components is Important to the prlnciple of its operation and its effectiveness. Therefore, it is the prlnciple of the plug and not Its size, which Is the subJect of the patent application.

The present Invention may be carried Into practice In various ways but one embodiment will now be described by way of example and with reference to Figure 1 which Is an exploded perspective view of the components In a sump plug seal.

The plug to which this patent application relates consists of four individual components, each of which combine to provide the unit, itself. The relationship between these Individual components provides the unit, which utilises the devised princlple. The four components, which are described in detail below, are: The bolt 10 The seal 12 The washer 14 The nut 16 The Bolt 10 This is a bolt 10 with a specifically tapered head 18, above a parallel thread 20. It can be manufactured from suitable metal or plastic material though it is suggested that, in the case of a sump plug In an engine, this would be of a material which can be permanently magnetised, in order to trap and hold metal fragments away from the working parts of the engine.

Therefore, in this particular use, it is anticipated that steel would be employed.

The maximum diameter of the bolt 10 is some two ml I I imetres (2mm) smaller than the diameter of a sump hole 22, itself, thus allowing the bolt 10 to be inserted from the outside or outer surface 24 of the sump or container. The bolt head has a taper 18, which may be stralght, from Its maximum diameter to the diameter of the threaded section, within the thickness of the central hub of the seal, so that, as the bolt Is drawn through the seal, it expands the seal.

The parallel threaded screw section of the bolt projects from the smallest diameter of the section to an extent that, when passed through the seal 12 and washer 14, two threads proJect to allow the nut 16 to gain purchase.

The tapered bolt, Itself, can be manufactured in a mass production process to normal tolerances, for instance on a capstan lathe. Similarly, if the bolt is constructed of a rigid plastic, it can be, again, mass produced by inject ion moulding methods within normal tolerance.

The Seal 12 The seal is manufactured from hard rubber compound or plastic material with elastic properties which allow it to expand and distort under the pressure exerted by the tapered head of the bolt. Naturally, this material must be resistant to the chemical I t is containing, e.g. oll resistant in an engine sump.

The seal 12 consists of a hub section 26 and a base 28 section, constructed In one piece. The hub section 26 is a rlng whose internal sides are parallel about a hole which Is one millimetre (imam) larger than the diameter of the threaded section of the bolt. The outer sides of the hub are generally parallel and of the diameter of the sump hole minus two mill imetres (D 2mm), however, the end of the hub ring widens to the diameter of the sump hole by means of a radius to provide a thin lip 30, approxlmately one millimetre (imam) thick at its extremity.

The length of the hub section is dependent upon the thickness of the sump pan In the vicinity of the sump drain hole and is expected to be between two millimetres (2mm) and five millimetres (5mm) greater than the sump pan thickness, depending upon the compressive nature of the material used to construct the seal.

The opposite end of the hub than that which has the expanded diameter, opens to form the base section 28.

The base, itself, consists of a ring whose diameter is approximately twice the diameter of the hub section and whose inner diameter is one millimetre (imam) larger than the diameter of the threaded section of the bolt.

The thickness of the base can be variable but, in the case of an engine sump plug, is expected to be five millimetres (5mm).

The base is formed from the same material as the hub section and, in practice, the seal would be manufactured as one unit. Again, the part lends Itself to Inexpensive mass production moulding techniques.

Washer 14 This part consists of a circular rlng of thin metal or plastic material, with an upturned lip 32 around Its outer edge. The internal diameter of the rlm Is one millimetre (imam) greater than the diameter of the base section of the seal. The rim, itself, stands proud of the washer by one third of the thickness of the base section of the seal. The washer has a central hole 34 whose diameter Is one millimetre (imam) greater than the diameter of the threaded section of the bolt.

If made from steel, it is anticipated that the thickness of the washer and rim will be approxlmately one millimetre (imam) but this Is a variable dimension subject to the stresses to be contalned In the appi Ication.

Nut 16 The nut is, to some degree, the most critical component of the sump plug assembly as this determines the extent to which the unit is tightened.

The nut consists of an Internally threaded, hexagonal nut whose dimensions match the standards which pertain to the thread of the bolt component. The threaded hole of the nut, however does not extend through the whole length of the nut but terminates at a stopped end. Therefore, the lower part of the nut, while retaining the outer hexagonal section and dimensions, is internally sol id, with a concave dome 36 which matches the end shape of the bolt.

This domed nut will therefore, only allow a specific number of turns on the bolt before the end of the bolt is prevented from travelling further by coming Into contact with the solid domed end. Thus, the nut cannot be over-tightened.

While the dimensions of the nut component are critical, they are dependent upon a number of factors In the finial design for any particular operation. The dimensions are, in fact, reiated to the thickness of the hub section of the seal and, hence, the length of the tapered head of the bolt. They are also dependent upon the compressibility of the material used in the construction of the seal. Furthermore, they are dependent upon the size and type of thread chosen. It Is anticipated, however, that, In addition to the two threads projecting to allow purchase of the nut upon the bolt, the nut will be allowed to gain purchase on six more threads. It is therefore anticipated that, in total, the nut will be dimensioned to allow eight full turns to a fully tight position.

Again, as normal threaded tolerances apply, the mass manufacture of the domed nut component should be achieved inexpensively.

APPLICATION OF THE NEW PLUG It will be appreciated from the description, above, that the seal fits inside the rimmed washer and the bolt and hub section of the seal fit through the sump hole.

Therefore, the four components can be assembled prior to insertion. In practice, the seal will be inserted into the washer, the bolt will then be passed through the seal and washer and the nut will be threaded on to the two projecting threads of the bolt. In this condition, the plug Is fully assembled but no loading has been applled to the seal.

The plug is then placed through the sump hole until the base of the seal is positioned against the outer face of the sump. in practice, it will be necessary to ease the radius lip of the seal hub through the sump hole which Is of equal size.

Once the plug Is In position, It i-s simply a matter of tightening the nut to Its full extent, against the dome. In practice, it should be possible to undertake the first part of this operatlon by turning the nut with the fingers, then, using a spanner to complete the action.

The effect of tightening the nut causes the tapered head of the bolt to be partially drawn through the seal. This causes the seal to expand outwards with the result that three sealing points are made by the one single action. First, the tapered head 18 creates a seal with the seal ring, internally. Secondly, the lip 30 of the seal hub is pressed over the Internal surface 38 of the sump, evenly around the sump hole, creating an internal seal. Thirdly, the base section 28 of the seal, contained by the washer, compresses against the outer surface 24 of the sump, evenly around the sump hole, providing an external seal.

In addition, the domed nut provides a final seal which prevents oil escaping through the threads and also prevents water, grit and other materials penetrating the threads at the bolt end, thus reducing corrosion problems. As a result, the unit Is protected to an extent which will allow its easy removal from the sump of a vehicle which has travel led, perhaps, In excess of ten thousand road miles between services.

In an alternative embodiment (not shown) any tendency for the bolt to slip relative to the seal may be reduced by having a knurled or rldged finish on the bolt head or, alternatively or additional ly on the abuting face of the seal with the bolt head. Alternatively or additionally, the bolt head and the Inner seal hole could be of a cross-section other than round, for Instance of square, pentagonal, hexagonal or octagonal.

One or both of the co-operating parts of the bolt head or seal may be tapered. Alternatively or additionally one or both of the bolt head or seal may have lugs.

In additlon to the advantages already stated above, such as ease of removal protection of threads, multiple sealing points and simple construction, the new plug unit offers other benefits. First, it eliminates the need to tap the sump itself, which, in turn, avoids problems of sump pan replacement or sump hole re-tapping, which occur when these threads become corroded or otherwise damaged. Secondly, the new plug could be retro-fitted to conventional sump holes. Thirdly, component manufacture should be competitively priced against existing plugs and, If necessary, component parts, such as the seal, could be replaced without need to replace the unit in its entirety.

Claims

1. A sealing arrangement comprising a flexible sealing member arranged to be Inserted at least partially into an opening, and an operating member arranged to extend at least partially through the sealing member, the sealing member and the operating member belng arranged to co-operate such that relative translational movement between the members in one direction Is arranged to cause the sealing member to be urged outwardly In a direction transverse to the direction of relative movement.

2. An arrangement as claimed In Claim 1 wherein the sealing member is arranged to extend through an opening.

3. An arrangement as claimed In Claim 1 or Claim 2 whereln the sealing member Is arranged to be inserted through one side of an opening and to seal with the other side of an opening.

4. An arrangement as claimed in Claim 3 wherein the sealing member Is arranged to seal with the surface defining the side of the opening through which the sealIng member is inserted.

5. An arrangement as claimed in any of the Claims 1 to 4 wherein relative translational movement between the members in one direction is arranged to urge the members Into sealing engagement with each other.

6. An arrangement as claimed in any of the Claims 1 to 5 wherein the operating member is arranged to be threadably engaged by a control member.

7. An arrangement as claimed In Claim 6 wherein relative movement between the screw threads of the control member and operating member is arranged to cause relative translational movement between the operating member and the sealing member.

8. An arrangement as claimed In any of the Claims 1 to 7 wherein the sealing member includes an enlarged portion of generally the same cross-section as the opening which It is to seal with.

9. An arrangement as claimed In any of the Claims 1 to 8 including means for limiting the extent of relative translational movement between the operating member and the sealing member in one direction.

10. An arrangement as claimed In Claim 6 or 7 and Claim 9 wherein said means comprises surfaces on the operating member and control member arranged to abut each other in a limiting position.

11. An arrangement as claimed in any of the Claims 1 to 10 wherein the operating member and the sealing member co-operate to Inhibit relative rotational movement between those members.

12. A sealing arrangement substantially as herein descr ibed with reference to and as shown In the accompanying drawings.

13. A method of sealing an opening comprising Inserting a flexible member and an operating member at least partially through the opening from one side thereof and causing relative translational movement between the members in the direction through the opening to cause the sealing member to be urged outwardly in a direction transverse to the direction of relative translational movement to seal with the opening.

14. A method as claimed in Claim 13 wherein the sealing member is urged outwardly by the relative translational movement between the members to seal with a surface defining the opposite side of the opening from that which the sealing member is inserted from.

15. A method as claimed In Claim 13 or Claim 14 comprising limiting the extent of relative translational movement between the members.

16. A method as claimed In Claim 15 wherein the relative translational movement is limited by abutment of a control member with the operating member.

17. A method as claimed in any of Claims 13 to 16 wherein a control member threadably engages with the operating member.

18. A method as claimed in Claim 16 to 17 wherein relative movement between the co-operating screw threads Is arranged to cause the relative translational movement between the operating member and the sealing member.

19. A method as clalmed In any of Claims 13 to 18 comprising forming a seal between the surface defining the opening from the side of the opening from which the sealing member is inserted and the sealing member.

20. A method as claimed In any of the Claims 13 to 19 wherein the operating member extends at least partially through the sealing member when the operating member and the sealing member are Inserted through the opening.

21. A method of sealing an opening substantially as herein described with reference to the accompanying drawing.

22. An arrangement as claimed In any of Clalms 1 to 12 when used in a method as clalmed In any of Clalms 13 to 21.