AU4878000A - A nut - Google Patents

Description

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT (Original) APPLICATION NO:

LODGED:

COMPLETE SPECIFICATION LODGED:

ACCEPTED:

PUBLISHED:

RELATED ART: NAME OF APPLICANT: ACTUAL INVENTOR: ADDRESS FOR SERVICE: INVENTION TITLE: JOHN FORD VERONICA FORD JOHN FORD LORD COMPANY Patent Trade Mark Attorneys 4 Douro Place West Perth, Western Australia, 6005

AUSTRALIA.

"A NUT" DETAILS OF ASSOCIATED PROVISIONAL APPLICATION NO'S: Australian Provisional Patent Application Number PQ1944 filed on August 2, 1999.

The following Statement is a full description of this invention including the best method of performing it known to me/us: 2

TITLE

"A SEALING NUT" The present invention relates to a sealing nut for engaging with an externally screw threaded bolt and, in combination with the externally screw threaded bolt, for exerting a clamping force on at least two members.

It is known to exert a clamping force on at least two members by passing an externally screw threaded bolt through apertures in the two members, engaging an internally screw threaded nut with the bolt and tightening the nut. In some *oo.

circumstances, it is desirable to provide a seal between the nut and an outwardly 10 facing surface of the member adjacent the nut, and to achieve this it is known to provide a partially resilient washer between the nut and the adjacent member. In some circumstances, it may also be desirable to maximise the friction between the nut and the bolt so as to reduce the risk of unintentional loosening of the nut, and to achieve *°ago this it is known to provide a nut of the type having a plastic insert portion which deforms when the nut is engaged with the bolt.

Such a nut, bolt and washer arrangement is commonly used in a grinding mill for tightly and sealably clamping a mill liner to a shell of the grinding mill. In this application, a liner bolt is inserted through the liner so as to protrude from the shell, a washer having a partially resilient portion is placed on the bolt, and the liner is clamped to the shell by engaging a plastic insert type nut with the bolt.

However, although the above arrangement is satisfactory in tightly and sealably clamping the liner to the shell, the arrangement suffers from a disadvantage in that the plastic insert type nut may only be used once. As a result, the nut has to be replaced each time the nut is removed.

3 The present invention seeks, therefore, among other things, to provide a sealing nut which overcomes the above mentioned disadvantage.

In accordance with an aspect of the present invention, there is provided a sealing nut comprising an annular resilient sealing washer and a nut member having an elongate aperture extending through the sealing nut along a longitudinal axis thereof, the elongate aperture including an internally screw threaded portion and an outwardly facing recessed portion arranged to receive the annular resilient sealing washer, the internally screw threaded portion being arranged to engage, in use, with an externally screw threaded bolt.

10 The present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:- Figure 1 is a diagrammatic cross sectional view of a sealing nut in accordance with the present invention; *°oooo Figure 2 is a perspective view of the sealing nut of Figure 1; Figure 3 is a diagrammatic cross sectional view of a nut member of the sealing nut of Figure 1; Figure 4 is a diagrammatic end view of the nut member shown in Figure 2 in the direction of the arrow in Figure 2; Figure 5 is a diagrammatic cross sectional view of the sealing nut shown in Figure 1 in use.

Figure 6 is a diagrammatic cross sectional view of a sealing nut in accordance with a second embodiment of the present invention.

Referring to Figures 1 to 4 of the drawings, there is shown a sealing nut 10 having a nut member 12 and a resilient sealing washer 14.

4 The nut member 12, as shown in Figures 2 and 3, has a head portion 11 with a generally cylindrical outer surface and a body portion 13 with a generally hexagonal shaped outer surface. The nut member 12 includes an elongate aperture 16. The elongate aperture 16 comprises an internally screw threaded portion 18 and a recessed portion 20. The internally screw threaded portion 18 is substantially within the body portion 13 of the nut member 12. The recessed portion 20 is of substantially disc-like configuration and extends inwardly of an end surface 23 of the head portion 11i.

The recessed portion 20 is defined by a circumferential first inclined wall 22 extending inwardly of the end surface 23 away from and at a shallow angle to the .9.

":t910 central longitudinal axis of the nut member 12, an annular lip portion 24 disposed in a plane substantially perpendicular to the central longitudinal axis and extending inwardly of the first inclined wall 22, and a circumferential second inclined wall 26 extending from the annular lip portion 24 towards the central longitudinal axis, away from the end surface 23 and at a shallow angle to the plane containing the annular lip portion 24.

S. In a preferred embodiment of the invention the shallow angle of the first and second circumferential inclined walls 22, 26 is in the range 100-25o.

The resilient sealing washer 14 is of generally annular configuration and includes a circumferential inwardly facing surface 28, a circumferential outwardly facing surface 30, a first flat annular surface 32 and an opposite second flat annular surface 34.

As shown in Figure 1, the resilient sealing washer 14 is configured such that the resilient sealing washer 14 fits snugly into the recessed portion 20 with the first flat annular surface 32 adjacent the annular lip portion 24. Preferably, the resilient sealing washer 14 is configured such that the smallest diameter defined by the circumferential first inclined wall 22 is slightly smaller than the diameter defined by the circumferential outwardly facing surface 30 of the resilient sealing washer 14. The resilient sealing washer 14 is also configured such that the diameter defined by the circumferential inwardly facing surface 28 is substantially the same as the external diameter of a bolt with which the sealing nut 10 is to be engaged in use.

The sealing nut 10 is shown engaged with a bolt 36 in use in Figure 5, the sealing nut and bolt 36 serving to clamp first and second members 40 and 42 together. The first and second members 40, 42 maybe a shell and a liner respectively of a grinding mill.

S 10 It will be understood that as the sealing nut 10 is rotated and thereby engaged with the bolt 36, the second annular surface 34 of the resilient sealing washer 14 comes into contact with an outer surface 44 of the first member 40. Continued rotation of the nut relative to the bolt 36 exerts a force on the resilient sealing washer 14 which tends to urge a portion of the first annular flat surface 32 to move towards the circumferential second inclined wall 26 and to urge a portion of the circumferential inwardly facing surface 28 adjacent the second annular surface 34 to move towards the bolt 36. As a result, portions of the resilient sealing washer 14 are urged to extend into spaces between turns of the bolt 36. Further rotation of the nut 10 relative to the bolt 36 has the effect of urging the remainder of the resilient sealing washer 14 to move into the recessed portion 20, of further urging portions of the resilient sealing washer 14 to extend into spaces between turns of the bolt 36, and of exerting forces against the circumferential first inclined wall 22, the annular lip portion 24, the circumferential second inclined wall 26 and the bolt 36. As a result, when the sealing nut 10 is in the position shown in Figure 4, the sealing nut 10 is tightly fixed relative 6 to the bolt 36 by the resilient sealing washer 14, the resilient sealing washer 14 also providing a substantially hermetic seal between the sealing nut 10, the bolt 36 and the first and second members 40, 42.

It will be understood, that the sealing nut 10 performs both the function of reducing the risk of the nut becoming loose during use and the function of providing a seal between the bolt and the first and second members, which functions have hitherto been performed by a plastic insert type nut and a washer respectively.

It will also be understood that since a plastic insert portion is not required, with the :..•sealing nut 10 of the present invention the sealing nut 10 may be used more than once, 10 the resilient sealing member 14 being replaced if necessary after each use.

It will be appreciated that although the outer surface of the body portion 13 is generally hexagonal shaped, other shaped body portions may alternatively be provided depending on the application.

°oe It will also be appreciated that the transverse dimension of the elongate aperture see* portion 16 and the corresponding internal diameter of the resilient sealing washer 14 may vary to suit the size of bolt with which the sealing nut is to be engaged in use.

A second embodiment of the present invention is shown in Figure 6. In this embodiment the nut member 12 includes an annular recess 46 extending into the internally screw threaded portion 18 at a location remote from the head portion 11. An annular resilient washer 48 is located within the annular recess 46.

In use, the annular resilient washer 48 provides an additional substantially hermetic seal between the bolt 36 and the nut member 12 to further reduce the risk of the nut becoming loose during use.

7 A third embodiment of the present invention is shown in Figures 7 and 8. In this embodiment the body portion 13 includes a plurality of longitudinal slots extending inwardly from an end of the body portion 13 remote from the head portion 11. In this embodiment the diameter of the slotted area of elongate aperture 16 may be reduced relative to the non-slotted area.

A fourth embodiment of the present invention is shown in Figure 9. In this embodiment the body portion 13 includes a single longitudinal slot 50 and a radial slot 52 extending radially of the longitudinal slot 50. The radial slot 50 extends through a 270° to 3300 arc within the body portion 13.

I Modifications and variations as would be apparent to a skilled addressee are deemed to be within the scope of the present invention.

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Claims (7)

1. A sealing nut comprising an annular resilient sealing washer and a nut member having an elongate aperture extending through the sealing nut along a longitudinal axis thereof, the elongate aperture including an internally screw threaded portion and an outwardly facing recessed portion arranged to receive the annular resilient sealing washer, the internally screw threaded portion being arranged to engage, in use, with an externally screw threaded bolt.

2. A sealing nut according to Claim 1, wherein the external diameter of the S.. annular resilient sealing washer is larger than the smallest diameter of the recessed oooo 10 portion.

3. A sealing nut according to Claim 1 or 2, wherein the recessed portion is of substantially disc like configuration, and includes a first circumferential wall extending inwardly of an outer face of the nut member, the first circumferential wall being inclined at a shallow angle to the longitudinal axis of the sealing nut such that the diameter of the recessed portion increases as the first circumferential wall extends inwardly of the outer face. o.

4. A sealing nut according to any one of the preceding claims, wherein the recessed portion includes a second circumferential wall extending away from the internally screw threaded portion, the second circumferential wall being inclined at a shallow angle to a plane extending transversely of the logitudinal axis of the sealing nut member such that the diameter of the recessed portion increases as the second circumferential wall extends away from the internally screw threaded portion.

A sealing nut according to Claims 3 or 4, wherein each shallow angle is in the range of 100-250. 9

6. A sealing nut according to any one of the above claims, wherein an annular recess is disposed within the internally screw threaded portion remote from the recessed portion, and an annular resilient washer is mounted within the annular recess.

7. A sealing nut substantially as hereinbefore described, with reference to, and as shown in, the accompanying drawings. DATED THIS 21 st DAY OF JULY 2000. 10 JOHN FORD VERONICA FORD By their Patent Attorneys LORD COMPANY PERTH, WESTERN AUSTRALIA