CA2924352A1

CA2924352A1 - Releasable fastener assembly

Info

Publication number: CA2924352A1
Application number: CA2924352A
Authority: CA
Inventors: Brian Davies
Original assignee: Brian Investments Pty Ltd
Current assignee: Brian Investments Pty Ltd
Priority date: 2013-08-19
Filing date: 2014-08-19
Publication date: 2015-02-26
Also published as: WO2015024053A1; ZA201601507B

Abstract

The present invention provides a releasable fastener assembly (11) for securing an object (19) to a structure (13). The structure comprising a first surface (15) and a second surface (17) against which the object is secured. The fastener assembly comprises a housing (43) adapted to be secured relative to the structure, a nut (63) adapted to be received in the housing and a bolt (73) adapted to pass through a hole (25) in the object and engage the nut. When the nut is received in the housing and the bolt fastened relative to the nut, the object is clampingly secured to the surface.

Description

Releasable Fastener Assembly TECHNICAL FIELD
[0001] The present invention generally relates to a releasable fastener assembly. In particular the invention relates to a fastener assembly to secure a first object to a second object, such as a structure wherein only one side of one of the objects may be readily accessible.
BACKGROUND ART

[0002] Fasteners are a common and well-used means to secure one object to another.
Typically when doing so an operator is able to access both sides of each object and can therefore easily tighten the fastener to ensure the two objects are securely fastened.
However, there are many instances where only one side of the object may be easily accessed. This is problematic when securing an object to another object using fasteners.

[0003] In the mining industry there are numerous applications where only one side of an object is accessible, particularly after the plant has been installed. One such application is in relation to securing wear liners to a structure. Wear liners are used extensively throughout the mining industry to protect those parts of structures which are exposed to wear. Due to their very nature, the wear liners are sacrificial and require regular replacement as they wear to a level where they no longer serve their purpose.
It is therefore important that the wear liners can be readily removed. However, due to the harsh operating conditions, it is also important that the wear liners are held firmly in place during their service cycle.

[0004] Wear liners are used to protect mills, transfer chutes, crushers and other structures. Once these structures have been installed the rear side of the structure is often concealed or is difficult to access.
In order to secure any object to these structures a number of solutions are available.

[0005] Fastening with conventional nuts and bolts or studded plates requires access by personnel to both sides of the structure. They therefore do not allow for quick and easy installation and removal.

[0006] Attachment methods which enable the attachment and removal of objects, particularly wear liners, from a single side of the structure are limited and have a number of disadvantages.

[0007] One of these solutions includes the use of a blind fastener or blind rivet.
Normally these methods do not allow the head of the fastener to be exposed to wear, as this would cause the failure of the retention system. They may also not be removable, rendering it difficult to replace the object secured to the structure.

[0008] A further deficiency in using some forms of blind fasteners is that they rely upon a complementary match of the surface profile of the structure with the engaging surface profile of the wear liner as they have a fixed 'grip length' i.e. it is important that the underside surface of the wear liner closely mirrors that of the surface it is to protect.
Where this does not occur the operator may be prevented from being able to install the fasteners to secure the object properly or at all.

[0009] Some blind fasteners also require complex parts in their design or specialised installation and removal tooling.

[0010] Other methods for securing and removing wear liners to structures involve welding of the liner to the structure and thermal cutting them away from the structure when ready to be replaced. This involves dangerous and time intensive 'hot work' every time the liner is changed. It can also be damaging to the structure and the new wear liner. In addition to this, the requirement for welding limits the range of suitable material which can be selected for use as a wear liner.

[0011] Several methods which allow for single-sided attachment and removal of a wear liner require the permanent fixing of an adapter or retainer to the structure.
The deficiency in many of these systems is that the adapters or retainers are vulnerable to damage, as they sit upon the surface of the structure which is exposed to wear. If these adapters or retainers are damaged, hot work including thermal cutting and welding is needed to replace it with a new one before another liner can be fitted.

[0012] The preceding discussion of the background art is intended to facilitate an understanding of the present invention only. The discussion is not an acknowledgement or admission that any of the material referred to is or was part of the common general knowledge as at the priority date of the application.
SUMMARY OF INVENTION

[0013] It is an object of this invention to provide to a releasable fastener assembly which ameliorates, mitigates or overcomes, at least one disadvantage of the prior art, or which will at least provide the public with a practical choice.

[0014] The present invention provides a releasable fastener assembly for securing an object to a structure, the structure comprising a first surface and a second surface against which the object is secured, wherein the first surface is not readily accessible once the structure is complete, the fastener assembly comprising:
a housing adapted to be secured to the structure;
a nut adapted to be received in the housing;
a bolt adapted to pass through the object and engage the nut whereupon the nut being received in the housing and the bolt fastened relative to the nut, the object is clampingly secured to the surface.

[0015] The present invention provides a releasable fastener assembly for securing an object to a structure, the structure comprising a first surface and a second surface against which the object is secured, the fastener assembly comprising:
a housing adapted to be secured relative to the structure;
a nut adapted to be received in the housing;
a bolt adapted to pass through a hole in the object and engage the nut;

whereupon the nut being received in the housing and the bolt fastened relative to the nut, the object is clampingly secured to the surface.

[0016] In contrast to the prior art the present invention allows the object to be easily installed, removed and replaced, particularly when only the second surface of the structure is readily accessible. The bolt and/or the nut can also be easily removed and replaced without requiring extensive modification of the structure. The housing may be secured to the structure during manufacture or after installation. The nut may then be placed within the housing prior to the object (e.g. wear liner) being secured to the structure. The fastener is designed to be used with structures where the first surface of the structure is not accessible once the structure is complete. However, it is to be understood that this invention is not limited to such a structure. It is readily understood that the present invention can be applied to all manner of structures, providing a convenient and quick means to secure and subsequently remove the object from the structure.

[0017] In one aspect of the invention the housing is secured to the structure during construction of the structure.

[0018] In another aspect of the invention the housing is secured to the structure after construction of the structure.

[0019] Preferably the housing is secured relative to an aperture in the structure. The housing may be secured directly to the structure or it may be secured to a separate plate or object which aligns with an aperture in the structure.

[0020] In one aspect of the invention the housing comprises a fixed rear wall.

[0021] In another aspect of the invention the housing comprises a rear wall which may be easily removed therefrom. In this regard the rear wall may be provided by a thin metal section which can be detached from the housing with minimal force or may be easily broached. The rear wall may be in the form of a cap which can be readily removed.

[0022] In yet another aspect of the invention the housing comprises a sleeve having a plug retained therein.

[0023] Adjacent a first end, the sleeve may have a threaded section for threadingly receiving the nut. Adjacent a second end, the sleeve may have a first annular ring. The sleeve may provide a second annular ring between the threaded section and the first annular ring, defining an annular surface extending inwardly, perpendicular to the sleeve wall.

[0024] The plug may have a first section of larger diameter than a second section. The diameter of the first section may be larger than the internal diameter of the first annular ring. The diameter of the second section may be smaller than the internal diameter of the first annular ring. The diameter of the second section may be slightly larger than the internal diameter of the first annular ring such that the second section may be snugly received in the first annular ring. The plug may be made from a resilient and/or deformable material. The plug may incorporate a blind bore for receiving the end portion of the shank. Preferably the blind bore is smaller in diameter than the diameter of the shank such that there is an interference fit therebetween when the shank is received in the blind bore.

[0025] When the sleeve and plug are assembled the second section of the plug is received through the first annular ring, while the first annular ring prevents the first section of the plug from passing through to therefore retain the plug within the sleeve.
When assembled, the outer surface of the first section of the plug remains proud of the annular surface. As the nut is received in the threaded section, and tightened relative to the housing, the nut clamps that part of the plug which is proud of the annular surface to provide a seal therebetween. When installing the fastener, as the shank is received through the nut, the end portion of the shank that extends through and out of the nut is received in the blind bore. As the blind bore is smaller in diameter than the end portion of the shank, an interference fit is formed between the two. This assists in retaining the shank in place (i.e. minimises accidental unwinding of the shank from the nut) as well as assists to seal the shank and nut to minimise corrosion and build up of dirt.

[0026] In yet another aspect of the invention the housing comprises a plug having a blind bore in an outer surface, and an annulus extending upwardly from the outer surface of the plug, wherein the nut is receivable in the annulus. The blind bore may be adapted to receive the portion of the shank that extends from the nut when the fastener is installed and fastened. Preferably the blind bore is smaller in diameter than the diameter of the shank such that here is an interference fit therebetween when the shank is received in the blind bore.

[0027] The housing may be in the form of a sleeve secured to the plug. At one end of the sleeve the sleeve ends may curve inwardly to secure the plug to the sleeve.

[0028] In yet another aspect of the invention the housing is solid and provides a first cavity for receiving the nut, and a second cavity for receiving the portion of the shank that extends from the nut when the fastener is installed and fastened, such that when the releasable fastening assembly is installed, the nut, and the portion of the shank housed in the housing are relatively sealed from the environment. This inhibits the ingress of materials in the housing which may lead to corrosion and make removal of the shank from the nut, and the nut from the housing difficult. Preferably the second cavity is smaller in diameter than the diameter of the shank such that here is an interference fit therebetween when the shank is received in the second cavity.

[0029] Preferably a face of the housing is flush with or recessed below the second surface of the structure when secured thereto.

[0030] Preferably the nut is threadingly received in the housing.

[0031] Preferably the housing incorporates a threaded section on an inner surface thereof for threading engagement with a thread on the outer surface of the nut.

[0032] Preferably a coating may be provided on the threaded section of the housing and/or a coating on the threads of the nut. The coating may be in the form of thread tape, a non-setting silicone, wax or binder. The coating may also inhibit rust and debris (especially mining fines) from forming on the threaded portions. The coating may also reduce any play/slack between the housing and the nut.

[0033] Preferably the nut is flush with or recessed below the face of the housing when received therein.

[0034] Preferably the nut is flush with or recessed below the second surface of the structure when received in the housing.

[0035] In one aspect of the invention the bolt comprises a shank extending from a head.

[0036] In another aspect of the invention the bolt comprises a shank extending from a locking element. An end of the shank remote from the locking element may be threadingly received in an aperture in the head of the bolt.

[0037] The shank may have a diameter smaller than the diameter of a bottom wall of the head.

[0038] Preferably the nut incorporates an aperture therein for receiving the shank.

[0039] In one aspect of the invention the aperture in the nut is threaded.

[0040] Preferably the shank incorporates a thread along its outer surface which threadingly engages the thread of the aperture to fasten the bolt relative to the nut.

[0041] In another aspect of the invention the aperture in the nut is in the form of a slot.

[0042] Preferably the locking element is receivable relative to the aperture when in a first position, and is releasably locked relative to the aperture when in a second position.

[0043] Preferably the locking element comprises a clamping portion and a locking member. The clamping portion may comprise two arms extending outwardly from the shank in an opposed relation.

[0044] Preferably the angular displacement of the locking element between the first position and second position is less than 180 .

[0045] Preferably the angular displacement of the locking element between the first position and second position is 90 .

[0046] Preferably an outer surface of the bolt head is flush with the second surface of the object when the object is clampingly secured to the structure.

[0047] The releasable fastener assembly may further comprise a rubber boot which may be secured to the housing once installed relative to the structure. This assists in sealing the housing and nut to minimise corrosion and the ingress of contaminants/dirt.

[0048] Preferably the head is adapted to co-operate with a tool to fasten the bolt relative to the nut.

[0049] Preferably the head has at least two openings in spaced relation, each opening is adapted to receive a corresponding projection of the tool, whereupon rotation of the tool the projections received in the openings cause the head to rotate to wind the shank into the nut to fasten the fastener, securing the object to the structure.
In those embodiments which incorporate a locking element rotation of the tool causes the head to rotate and causes the locking element to move from the first position to the second position, when installing the fastener, and vice versa when removing the fastener.
When installing the fastener, further rotation of the head will result in the object being clampingly secured between the surface and the head while the locking element remains in the second position.

[0050] The openings may extend from the upper surface of the head and terminate adjacent the bottom wall of the head. The openings may be parallel relative to each other. This ensures the tool can be used to rotate the head regardless of its wear profile.

[0051]

[0052] The bolt may comprise a sensor. The sensor measures the wear experienced by the bolt and transmits this data so that an operator is able to predict when the wear liner may need to be replaced. The sensor may transmit data via a wired infrastructure or through a wireless system.

[0053] Preferably the sensor extends through the bolt and terminates in close proximity to the outer surface of the bolt head. In typical installations the outer surface is exposed to wear.

[0054] Preferably the sensor is received in a cavity in the shank of the bolt, or the shank and head of the bolt. when they form a unitary member

[0055] Preferably the sensor has a transmitter secured to or relative to the end of the shank for transmitting data collected by the sensor.

[0056] In one aspect of the invention the housing has a passage passing therethrough for receiving the sensor. The housing is adapted to receive a protective shroud for protecting the transmitter when the bolt is fastened relative to the nut. The housing may have a sleeve extending rearwardly to receive the shroud thereon.

[0057] The present invention provides a structure adapted to have a plurality of wear liners secured thereto using a plurality of fasteners as herein before described..

[0058] In those embodiments in which the nut comprises a slotted aperture, the locking element is receivable in the slotted aperture in the nut when the locking element is in a first position, and is releasably locked with respect to the structure when the locking element is in a second position.

[0059] Preferably the head is received in a hole in the object such that an outer surface of the head is flush with the outer surface of the object when the fastener is installed.

[0060] A sidewall of the head may provide a tapered portion. The tapered portion may extend along the length of the sidewall of the head to define a generally frusto-conical head. The head may have a first tapered sidewall and a second tapered sidewall, defining a step in the sidewall of the head at the junction of the first tapered sidewall and the second tapered sidewall. The second tapered sidewall may be adjacent a bottom wall of the head and be of a larger diameter than the first tapered sidewall at the junction. In those embodiments in which the sidewall of the opening is also tapered, the configuration of the head ensures the bottom section of the sidewall of the head remains in contact with the sidewall of the hole as the head wears.
It also accommodates variations in the opening which may otherwise lead to unsatisfactory positioning of the bolt within the hole when installed and fastened. If upon installation the head of the bolt is only in contact with the upper portion of the sidewall of the opening, then as the head and object wears beyond the areas of initial contact, the bolt and object may become loose and the attachment of the object to the structure will be compromised. The configuration of the head enables the clamping forces to be distributed through the sidewall of the hole of the object through the service life of the object, leading to a more robust means of securing the object to the structure.

[0061] The shank may have a diameter smaller than the width of the bottom wall of the head. The shank may have a diameter smaller than the diameter of the bottom wall of the head.

[0062] In one aspect of the invention the hole in the object is shaped to complement the head, wherein a sidewall of the hole is the same or similarly tapered as the tapered portion of the head.

[0063] In another aspect of the invention the angle of the sidewall of the hole is slightly offset to the angle of the tapered portion of the head.

[0064] The locking element may be located at an end of the shank remote from the head.

[0065] In one aspect of the invention the locking element is formed integral with the shank to provide a unitary member.

[0066] Preferably the shank is threadingly received in the head. In this arrangement rotation of the head may wind the head on or off the shank.

[0067] Preferably there is resistive engagement between the head and the shank, whereby the resistive engagement causes the shank to rotate with the head when the head is rotated, the resistive engagement being overcome when the locking element secured to the shank has passed to the second position and sufficient force is applied thereto to overcome the resistive engagement. Further rotation of the head then fastens the bolt.

[0068] The resistive engagement may be provided by a coating on the external threads of the shank and/or a coating on the internal threads of the head. The coating may be in the form of thread tape, a non-setting silicone, wax or binder. The coating may also inhibit rust and debris (especially mining fines) from forming on the threaded portions.
The coating may also reduce any play/slack between the head and the shank.

[0069] In another aspect of the invention the locking element is threadingly received on the shank. Preferably the shank is formed integral with the head to provide a unitary member. In this arrangement rotation of the head may wind the head and shank on or off the locking element.

[0070] Preferably there is resistive engagement between the shank and the locking element, whereby the resistive engagement causes the locking element to rotate with the shank when the shank is rotated, the resistive engagement being overcome when the locking element has passed to a second position and sufficient force is applied thereto to overcome the resistive engagement. Further rotation of the head then fastens the bolt.

[0071] The resistive engagement may be provided by a coating on the external threads of the shank and/or a coating on the internal threads of the locking element.
The coating may be in the form of thread tape, a non-setting silicone, wax or binder. The coating may also inhibit rust and debris (especially mining fines) from forming on the threaded portions. The coating may also reduce any play/slack between the locking element and the shank.

[0072] In those embodiments where the locking element is threadingly received upon the shank, the resistive engagement may be provided by a nylon ring incorporated in the locking element.

[0073] In those embodiments where the locking element is threadingly received upon the shank, the shank has a stop located at its end to prevent the locking element from being wound completed off the shank.

[0074] Preferably the locking element comprises a clamping portion wherein the clamping portion assists in clamping the object to the structure.

[0075] Preferably the locking element comprises a locking member to lock the clamping portion in a manner which prevents rotation of the clamping portion beyond the second position.

[0076] Preferably the locking element further comprises a mating surface which aligns with and mates with a complementary mating surface of the slotted aperture in the nut to releasably retain the locking element with respect to the aperture when the locking element is in the second position.

[0077] Preferably the angular displacement of the locking element between the first position and second position is less than 180 .

[0078] Preferably the angular displacement of the locking element between the first position and second position is 90 .

[0079] Preferably the bolt comprises an identification means to identify whether the locking element is in the first position or second position. The identification means may be in the form of indicia on an end of the shank adjacent the head. This is particularly beneficial when the locking element and shank are integrally formed.

[0080] Preferably the fastener comprises a retaining means to retain the locking element in the second position.

[0081] Preferably the retaining means assists to prevent, or at least minimise accidental rotation of the locking element from the second position to the first position. The retaining means may be in the form of a detent arrangement.

[0082] The detent arrangement may be in the form of a resilient projection extending from a surface of the locking member, whereby the projection engages the side of the aperture as the locking element passes between the first position to the second position. The projection may provide resistance to the rotation of the locking element, whereby when a prescribed force is applied the initial resistance is overcome, causing the resilient projection to deform or retract to allow the further rotation of the locking element to the second position.

[0083] The resilient projection may be vulcanised or glued to the surface of the locking member. The resilient projection may be silicon.

[0084] Preferably the initial resistance provided by the projection is less than the resistive engagement between the head and the unitary shank and locking element.
This allows an operator to rotate the head, resulting in simultaneous rotation of the unitary shank and locking element, and causing the locking element to move from the first position to the second position.

[0085] Preferably the initial resistance provided by the projection is less than the resistive engagement between the shank and the locking element. This allows an operator to rotate the unitary head and shank, resulting in simultaneous rotation of the locking element, causing the locking element to move from the first position to the second position.

[0086]The resilient projection may be on at least one of the curved surfaces.

[0087]The locking member may be adjacent the clamping portion.

[0088] A portion of the locking member may be confined to the slotted aperture in the nut when the locking element is received in the aperture and the object and structure are not securely clamped between the head and the locking element. Before the bolt has been fastened and the object secured to the structure, the locking member is partially located within the aperture. In this position the object may still be retained relative to the structure but the object is capable of a degree of movement relative to the structure. The bolt will need to be fastened in order to secure the object to the structure.

[0089] The locking member may be completely confined to the slotted aperture in the nut when the locking element is received in the aperture and the object and structure are securely clamped between the head and the locking element. When the bolt has been fastened and the object is secured to the structure such that object is held in position, the locking member is located in the confines of the aperture and the clamping portion bears against the surface of the structure adjacent the aperture.

[0090] The cross sectional profile of the locking member may have a first dimension which is less than the smallest dimension of the aperture, and a second dimension greater than the smallest dimension of the aperture such that as the locking member is rotated the locking element may be rotated between the first position and the second position. With this arrangement the locking element may only be rotated from the first position to the second position, and rotated in the reverse direction from the second position to the first position. The configuration of the locking member prevents rotation of the locking element past the second position.

[0091] The cross sectional profile of the locking member is of a rectangular or square configuration modified such that two diagonally opposed corners are curved such that as the locking member is rotated the curved corners permit the locking element to be rotated between the first position and the second position. Preferably the distance between the two curved corners is equal to or less than the smallest dimension of the slotted aperture in the nut. Preferably the distance between the two non curved corners is greater than the smallest dimension of the aperture.

[0092] Preferably the clamping portion comprises two arms extending outwardly relative to the locking member in an opposed relation. The extent of the arms is less than the largest dimension of the slotted aperture in the nut such that the clamping portion may be received therethrough.

[0093] The hole in the object may have a diameter which is greater than the extent of the two arms. The smallest diameter of the tapered sidewall of the hole is greater than the extent of the two arms. .

[0094] The smallest diameter of the tapered sidewall of the hole may be smaller than the smallest diameter of the head. With this configuration the bottom wall of the head is spaced from the structure when the bolt is installed and fastened. In another embodiment the smallest diameter of the tapered sidewall of the hole is sized such that when the head is received therein and the bolt is installed and fastened, the bottom wall of the head is in direct engagement with the structure while the sidewall of the head is still able to engage with the sidewall of the hole.

[0095] When the locking element is in the first position the clamping portion is arranged such that it aligns with the slotted aperture, allowing the arms to pass therethrough.
When the locking element is in the second position, the clamping portion bears against the back of the nut as the bolt is tightened. In the ideal situation, the bolt is only removed from the structure after the bolt is loosened and the locking element rotated back to the first position.

[0096] Once the bolt is installed the openings in the head may be filled with a removable material. Each opening may have a plug inserted in the bottom of the opening before a material is placed therein to seal the opening. The filling of the opening ensures that each opening is not compromised during the objects service life, allowing the tool to readily engage the openings, rotate the head, and remove the fastener when required.
BRIEF DESCRIPTION OF THE DRAWINGS

[0097] Further features of the present invention are more fully described in the following description of several non-limiting embodiments thereof. This description is included solely for the purposes of exemplifying the present invention. It should not be understood as a restriction on the broad summary, disclosure or description of the invention as set out above. The description will be made with reference to the accompanying drawings in which:
Figure 1 is a perspective front view of a housing of a fastener assembly according to a first embodiment of the invention;
Figure 2 is a perspective front view of a nut of the fastener assembly according to the first embodiment of the invention;
Figure 3 is a perspective side view of a bolt of the fastener assembly according to the first embodiment of the invention;
Figure 4 is a perspective view of the fastener assembly according to the first embodiment of the invention showing the nut received in the housing;
Figure 5 is a perspective view of the fastener assembly according to the first embodiment of the invention showing the housing secured to a structure (depicted as a section of a plate);
Figure 6 is similar to figure 5 with the nut received in the housing;
Figure 7 is similar to figure 6 with the bolt securing the wear liner (depicted as a section of a plate) to the structure;
Figure 8 shows a first surface of the structure with housing of the second embodiment and a further embodiment secured thereto;
Figure 9 is a perspective front view of a housing of a fastener assembly according to a second embodiment of the invention;

Figure 10 is a perspective front view of a nut of the fastener assembly according to the second embodiment of the invention;
Figure 11 is a perspective side view of a bolt of the fastener assembly according to the second embodiment of the invention;
Figure 12 is a perspective view showing the nut of figure 10 received in a housing of a third embodiment of the invention;
Figure 13 is a perspective side view showing a nut received in a housing of a fourth embodiment of the invention;
Figure 14 is a perspective side view showing a bolt partially received in the housing and nut shown in figure 13;
Figure 15 is a perspective view of a tool for securing and releasing the nut of figure relative to the housing, as well as the bolt relative to the nut;
Figure 16 is a perspective view of a further tool to assist in securing the housing to the structure;
Figure 17 is an exploded view showing a housing of a fifth embodiment of the invention; and Figure 18 is an assembled front view of the housing shown in figure 17.

[0098] In the drawings like structures are referred to by like numerals throughout the several views. The drawings shown are not necessarily to scale, with emphasis instead generally being placed upon illustrating the principles of the present invention.
DESCRIPTION OF EMBODIMENTS

[0099] The present invention provides a fastener assembly for securing a first object to a second object, or a structure. In the embodiments discussed below, the fastener assembly is specifically designed to secure an object in the form of a wear liner 19 to a structure 13, such as a transfer chute, whereby the fastener assembly allows the wear liner to be quickly installed on and removed from the structure.

[00100] While the present invention provides a very quick and easy fastener to secure a wear liner 19 to a second surface 17 of the structure 13, it has particular application for those structures 13 having a first surface 15 which is either concealed or which is not readily accessible during wear liner replacement..

[00101] The wear liner 19 comprises a first surface 21, which is secured against the second surface 17 of the structure 13 and a second surface 23. The second surface of the wear liner is exposed to wear. The wear liner comprises a plurality of holes 25 to assist in securing the wear liner to the structure, as is described below.

[00102] For ease of illustration the structure and wear liner are represented by a plate section, as can be noted in figures 5, 6 and 7.

[00103] Referring to figures 1 to 7, the invention according to the first embodiment is in the form of a fastener assembly 11 comprising a housing 43, a nut 63 and a bolt 73.

[00104] The housing 43 is cup-like in configuration comprising a void 44 defined by a rear wall 47 of the housing 43 and sidewalls 48. The inner surface 45 of the sidewall 48 is configured to provide a threaded profile for reasons described below. The outer periphery of the sidewall 48 is configured to provide a reduced outer diameter 49. The reduced outer diameter region 49 assists in fixing the housing to the structure.

[00105] The nut 63 has an outer surface 65 configured to provide a threaded profile, whereby the nut 63 can be threadingly received in the housing 43, as shown in figure 4.
The nut 63 incorporates an aperture 66. An inner surface 67 of the aperture 66 is configured to provide a threaded profile for reasons described below. The nut 63 also incorporates three openings 69 adapted to receive corresponding projections 403 of a tool 401, as shown in figure 15, to secure and remove the nut 63 from the housing 43.

[00106] The bolt 73 has a shank 75 extending from a tapered head 77. The shank 75 is configured to provide a threaded profile, whereby the shank 75 can be threadingly received in the aperture 66 of the nut 63.

[00107] Several steps of installation of the fastening assembly 11 of the first embodiment are shown in figures 5, 6 and 7. As shown in figure 5, the housing 43 is secured in an aperture 27 in the structure 13 such that when in position a face 46 of the housing is located below the second surface 17. As shown in figure 6, the nut 63 is threadingly received in the housing 43 such that the nut 43 is also located below the second surface 17 of the structure 13. Where required, the tool 401 may be used to position the nut 63 in the housing 43. Once the nut 63 is in position, the wear liner 19 may be placed on the structure such that each hole 25 in the wear liner 19 aligns with corresponding holes 27 in the structure. Using the tool 401, the bolt 73 may be threadingly received in the aperture 66 of the nut. Using a torque wrench or other device, the bolt 73 may be tightened to the required torque, securing the wear liner 19 to the structure 13.

[00108] When required, the wear liner 19 may be removed from the structure by removing the bolt 73, allowing the wear liner to be removed and replaced. When replacing the wear liner 19 the bolt 73, which also experiences wear, can also be replaced. Also, if required, the nut 63 is easily replaced when the wear liner 19 has been removed from the structure 13.

[00109] Each hole 25 located in the wear liner 19 is tapered in a complementary fashion to the tapered head 77 of the bolt 73 such that when the wear liner 19 is secured to the structure 13, the outer surface of the bolt 73 is substantially flush with the second surface 23 of the wear liner 19, as shown in figure 7.

[00110] Figure 8 illustrates a section of the first surface 15 of a structure 13. The section has six apertures 27, two of which are not supporting a housing. Each of the middle pair of apertures 27 support a housing 243 which has been fitted to the structure 13 after construction of the structure has been completed, leaving the first surface 15 relatively inaccessible. Under these conditions a housing 243 as shown in figure 9 is fitted to the structure. The housing 243 has a sidewall which has a tapered edge in a region adjacent its open end. In order to fit the housing 243 a hole larger than the outer diameter of the housing 243 is created in the structure 13. The housing 243 is then fixed in place, such as by welding. Any material which projects beyond the second surface of the structure is then removed.

[00111] Each of the remaining pair of apertures 27 also support a housing 143 that has been fitted to the structure 13 after construction of the structure has been completed. The housing 143 is adapted to receive a protective shroud which will be discussed below.

[00112] A second embodiment of the fastener assembly 111 is illustrated in figures 9 to 11. In this embodiment the fastener assembly 111 comprises a housing 243, a nut 163 and a bolt 173.

[00113] The housing 243 is cup-like in configuration comprising a void 44 defined by a rear wall 47 of the housing 243 and sidewalls 248. The inner surface 45 of the sidewall 248 is configured to provide a threaded profile for reasons described below.
The outer periphery of the sidewall 248 is configured to provide a tapered edge 249.
The tapered edge 249 assists in fixing the housing to the structure.

[00114] The nut 163 has an outer surface 165 configured to provide a threaded profile, whereby the nut 163 can be threadingly received in the housing 143, as per the first embodiment. The nut 163 incorporates a aperture in the form of a slot 166. The slot 166 is defined by two flat inner surfaces 169 in parallel relation, and two arced inner surfaces 171 extending between the inner surfaces 169.

[00115] The bolt 173 comprises a tapered head 177 which is connected to a locking element 175 so as to be spaced apart. The locking element 175 is adapted to be received in and cooperate with the slot 166 of the nut 163 to retain the bolt 173 relative to the nut 163.

[00116] The locking element 175 has a clamping portion in the form of a plurality of arms 181 extending outwardly from a central axis at a distal end 182 of the bolt 173.
The extent of the arms 181 is less than the length of the slot 166 such that the locking element 175 may be received therein. The locking element 175 also comprises a locking member 183 located adjacent the arms 181. The cross sectional profile of the locking member 183 is of a rectangular configuration modified such that two diagonally opposed corners 185 are curved.

[00117] In operation the bolt 173 is moveable between a first position, wherein the locking element 175 of the bolt 173 is receivable in the slot 166, and a second position wherein the bolt is retained relative to the nut. When in the second position, arms 181 abut a rear surface of the nut 163 adjacent the flat inner surface 169, preventing the bolt from being removed from the nut 163. In this position the fastening assembly secures the wear liner to the structure.

[00118] When the locking element 175 of the bolt 173 is receivable in the slot 166 the tool 401 may be used to rotate the bolt between the first position and the second position, which in this embodiment is 900.

[00119] A further embodiment is illustrated in figure 12. This embodiment combines the same housing 243 illustrated in figure 1, in combination with the nut163 illustrated in figure 10.

[00120] A fourth embodiment of the fastener assembly 211 is illustrated in figures 13 and 14. In this embodiment the fastener assembly 211 comprises a housing 143, a nut 163 and a bolt 273.

[00121] The bolt 273 is similar in construction to the bolt of the second embodiment.
However, in this embodiment the bolt is fitted with an internal wear sensor.
The wear sensor extends along the length of the bolt from adjacent the end surface of the tapered head, and is connected to a transmitter 151 secured to the end of the locking element 175.

[00122] The housing 143 supports a shroud 149 which is received in a sleeve extending rearwardly of the housing 143. The shroud acts to protect the transmitter when the bolt 273 is received in the slot 166 of the nut 163.

[00123] As noted above, figure 15 provides a tool 401 which assists in securing and releasing the nut from the housing. The tool 401 has an end 405 which may connect with a tool, such as a pneumatic driver capable of rotating the tool 401. As previously noted, projections 403 of the tool 401 engage corresponding apertures 69 in the nut to release and secure the nut. Projections 403 are also adapted to engage the apertures 79 in the bolt for securing and releasing the bolt. The apertures 79 extend through the head of the bolt such that the tool 401 can still engage and release the bolt after substantial wear.

[00124] When fitting a housing to a structure post-construction, the housing may be held in place using the support tool 421 shown in figure 16. The support tool comprises three outwardly extending arms 423 which may engage the second surface 17 of the structure 13, and a plurality of magnets 425, to hold the housing relative to the tool 421. The housing may then be secured to the structure while the tool holds the housing in place,. This is particularly beneficial when securing the housing from the inside of the side wall.

[00125] A fifth embodiment of the fastener assembly is illustrated in figures 17 and 18. In this embodiment the fastener assembly is different in that the housing comprises a sleeve 571 and a plug 573 retained therein.

[00126] Adjacent a first end 575, the sleeve has a threaded section 577 for threadingly receiving the nut (not shown). Adjacent a second end 579, the sleeve 571 has a first annular ring 581. The sleeve 571 provides a second annular ring between the threaded section 577 and the first annular ring 581, defining an annular surface 585 extending inwardly, perpendicular to the sleeve wall.

[00127] The plug 573 has a first section 587 of larger diameter than a second section 589. The diameter of the first section is larger than the internal diameter of the first annular ring 581. The diameter of the second section 589 is sized so as to be snugly received in the first annular ring 581.

[00128] The plug 573 is made from a resilient material and incorporates a blind bore 591 for receiving the end portion of the shank when the fastener is installed.
The blind bore 591 is smaller in diameter than the diameter of the shank such that there is an interference fit therebetween when the shank is received in the blind bore.

[00129] When the sleeve and plug are assembled, as shown in figure 18, the second section 589 of the plug is received through the first annular ring 581, while the first annular ring prevents the first section 591 of the plug 573 from passing through to therefore retain the plug within the sleeve.

[00130] When assembled, the outer surface 593 of the first section of the plug remains proud of the annular surface 585. When the nut is received in the threaded section, and tightened relative to the housing, the nut clamps that part of the plug which is proud of the annular surface to form a seal.

[00131] When installing the fastener, as the shank is received through the nut, the end portion of the shank that extends through and out of the nut is received in the blind bore 591. As the blind bore is smaller in diameter than the end portion of the shank, an interference fit is formed between the two. This assists in retaining the shank in place (i.e. minimises accidental unwinding of the shank from the nut) as well as assists to seal the shank and nut to minimise corrosion and build up of dirt.

[00132] Modifications and variations such as would be apparent to the skilled addressee are considered to fall within the scope of the present invention.
The present invention is not to be limited in scope by any of the specific embodiments described herein. These embodiments are intended for the purpose of exemplification only.
Functionally equivalent products, formulations and methods are clearly within the scope of the invention as described herein.

[00133] Reference to positional descriptions, such as lower and upper, are to be taken in context of the embodiments depicted in the figures, and are not to be taken as limiting the invention to the literal interpretation of the term but rather as would be understood by the skilled addressee.

[00134] Throughout this specification, unless the context requires otherwise, the word "comprise" or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.

Claims

1. A releasable fastener assembly for securing an object to a structure, the structure comprising a first surface and a second surface against which the object is secured, the fastener assembly comprising:
a housing adapted to be secured relative to the structure;
a nut adapted to be received in the housing;
a bolt adapted to pass through a hole in the object and engage the nut;
whereupon the nut being received in the housing and the bolt fastened relative to the nut, the object is clampingly secured to the surface.

2. The releasable fastener assembly according to claim 1 wherein the housing is secured relative to an aperture in the structure.

3. The releasable fastener assembly according to claim 1 or 2 wherein the housing comprises a fixed rear wall.

4. The releasable fastener assembly according to claim 1 or 2 wherein the housing comprises a rear wall which may be easily removed therefrom.

5. The releasable fastener assembly according to claim 4 wherein the rear wall is provided by a thin metal section which can be detached from the housing with minimal force or may be easily broached.

6. The releasable fastener assembly according to claim 4 wherein the rear wall is in the form of a cap which can be readily removed.

7. The releasable fastener assembly according to claim 1 or 2 wherein the housing comprises a sleeve having a plug retained therein.

8. The releasable fastener assembly according to claim 7 wherein adjacent a first end of the sleeve, the sleeve has a threaded section for threadingly receiving the nut.

9. The releasable fastener assembly according to claim 8 wherein adjacent a second end, the sleeve haa a first annular ring, and a second annular ring between the threaded section and the first annular ring, defining an annular surface extending inwardly, perpendicular to the sleeve wall.

10. The releasable fastener assembly according to claim 7, 8 or 9 wherein the plug has a first section of larger diameter than a second section.

11. The releasable fastener assembly according to claim 10 wherein the diameter of the first section is larger than the internal diameter of the first annular ring.

12. The releasable fastener assembly according to claim 10 or 11 wherein the diameter of the second section is smaller than the internal diameter of the first annular ring, or is slightly larger than the internal diameter of the first annular ring such that the second section may be snugly received in the first annular ring.

13. The releasable fastener assembly according to any one of claims 7 to 12 wherein the plug is made from a resilient and/or deformable material.

14. The releasable fastener assembly according to any one of claims 7 to 13 wherein the plug incorporates a blind bore adapted to receive the end portion of a threaded shank.

15. The releasable fastener assembly according to claim 14 wherein the blind bore is smaller in diameter than the diameter of the shank such that there is an interference fit therebetween when the shank is received in the blind bore.

16. The releasable fastener assembly according to any oen of claims to 15 whereby when the sleeve and plug are assembled the second section of the plug is received through the first annular ring, while the first annular ring prevents the first section of the plug from passing through to therefore retain the plug within the sleeve, wherein an outer surface of the first section of the plug remains proud of the annular surface.

17. The releasable fastener assembly according to claim 1 or 2 wherein the housing comprises a plug having a blind bore in an outer surface, and an annulus extending upwardly from the outer surface of the plug, wherein the nut is receivable in the annulus.

18. The releasable fastener assembly according to claim 17 wherein the blind bore is adapted to receive the portion of the shank that extends from the rear of the nut when the fastener is installed and fastened.

19. The releasable fastener assembly according to claim 17 or 18 wherein the blind bore is smaller in diameter than the diameter of the shank such that here is an interference fit therebetween when the shank is received in the blind bore.

20. The releasable fastener assembly according to claim 17, 18 or 19 wherein the housing is in the form of a sleeve secured to the plug.

21. The releasable fastener assembly according to claim 19 or 20 wherein an end of the sleeve the curves inwardly to secure the plug to the sleeve.

22. The releasable fastener assembly according to claim 1 or 2 wherein the housing is solid and provides a first cavity for receiving the nut, and a second cavity for receiving the portion of the shank that extends from the nut when the fastener is installed and fastened, such that when the releasable fastening assembly is installed, the nut, and the portion of the shank housed in the housing are relatively sealed from the environment.

23. The releasable fastener assembly according to claim 22 wherein the second cavity is smaller in diameter than the diameter of the shank such that here is an interference fit therebetween when the shank is received in the second cavity.

24. The releasable fastener assembly according to any one of the preceding claims wherein a face of the housing is flush with or recessed below the second surface of the structure when secured thereto.

25. The releasable fastener assembly according to any one of the preceding claims wherein the nut is threadingly received in the housing.

26. The releasable fastener assembly according to claim 23 wherein the housing incorporates a threaded section on an inner surface thereof for threading engagement with a thread on the outer surface of the nut.

27. The releasable fastener assembly according to claim 26 wherein a coating is provided on the threaded section of the housing and/or a coating on the threads of the nut.

28. The releasable fastener assembly according to claim 27 wherein the coating is in the form of thread tape, a non-setting silicone, wax or binder.

29. The releasable fastener assembly according to claim 22, 23 or 24 wherein the nut is flush with or recessed below the face of the housing when received therein.

30. The releasable fastener assembly according to any one of the preceding claims wherein the nut is flush with or recessed below the second surface of the structure when received in the housing.

31. The releasable fastener assembly according to any one of the preceding claims wherein the bolt comprises the shank extending from a head.

32. The releasable fastener assembly according to any one of claims 1 to 30 wherein the bolt comprises a shank extending from a locking element.

33. The releasable fastener assembly according to claim 32 wherein an end of the shank remote from the locking element is threadingly received in an aperture in the head of the bolt.

34. The releasable fastener assembly according to any one of claims 8 to 33 wherein the shank has a diameter smaller than the diameter of a bottom wall of the head.

35. The releasable fastener assembly according to any one of claims 819 to 34 wherein the nut incorporates an aperture therein for receiving the shank.

36. The releasable fastener assembly according to claim 35 wherein the aperture in the nut is threaded.

37. The releasable fastener assembly according to claim 35 or 36 wherein the shank incorporates a thread along its outer surface which threadingly engages the thread of the aperture to fasten the bolt relative to the nut.

38. The releasable fastener assembly according to claim 35 wherein the aperture in the nut is in the form of a slot.

39. The releasable fastener assembly according to claim 38 wherein the locking element is receivable relative to the slot when in a first position, and is releasably locked relative to the slot when in a second position.

40. The releasable fastener assembly according to claim 39 wherein the locking element comprises a clamping portion and a locking member.

41. The releasable fastener assembly according to claim 40 wherein the clamping portion comprises two arms extending outwardly from the shank in an opposed relation.

42. The releasable fastener assembly according to any one of claims 39 to 41 wherein the angular displacement of the locking element between the first position and second position is less than 180 .

43. The releasable fastener assembly according to any one of claims 39 to 41 wherein the angular displacement of the locking element between the first position and second position is 90°.

44. The releasable fastener assembly according to any one claims 17 to 43 wherein an outer surface of the bolt head is flush with the second surface of the object when the object is clampingly secured to the structure.

45. The releasable fastener assembly according to any one of the preceding claims comprising a rubber boot which may be secured to the housing once installed relative to the structure.

46. The releasable fastener assembly according to any one claims 17 to 45 wherein the head is adapted to co-operate with a tool to fasten the bolt relative to the nut, the head has at least two openings in spaced relation, each opening is adapted to receive a corresponding projection of the tool, whereupon rotation of the tool the projections received in the openings cause the head to rotate to wind the shank into the nut to fasten the fastener, securing the object to the structure.

47. The releasable fastener assembly according to any one claims 17 to 45 wherein the head is adapted to co-operate with a tool to fasten the bolt relative to the nut, the head has at least two openings in spaced relation, each opening is adapted to receive a corresponding projection of the tool, whereupon rotation of the tool the projections received in the openings cause the head to rotate, causing the locking element to move from the first position to the second position, when installing the fastener, and vice versa when removing the fastener.

48. The releasable fastener assembly according to claim 47 wherein the openings extend from the upper surface of the head and terminate adjacent the bottom wall of the head, the openings are parallel relative to each other.

49. The releasable fastener assembly according to any one of the preceding claims comprising a sensor connected to the bolt.

50. The releasable fastener assembly according to claim 49 wherein the sensor extends through the bolt and terminates in close proximity to the outer surface of the bolt head.

51. The releasable fastener assembly according to claim 49 or 50 wherein the sensor is received in a cavity in the shank of the bolt, or the shank and head of the bolt.

52. The releasable fastener assembly according to claim 49, 50 or 51 wherein the housing has a passage passing therethrough for receiving the sensor, the housing is adapted to receive a protective shroud for protecting the transmitter when the bolt is fastened relative to the nut.

53. A structure adapted to have a plurality of wear plates secured thereto using a plurality of fastener assemblies according to any one of the preceding claims.

54. A releasable fastener assembly for securing an object to a structure, the structure comprising a first surface and a second surface against which the object is secured, wherein the first surface is not readily accessible once the structure is complete, the fastener assembly comprising:
a housing adapted to be secured to the structure;
a nut adapted to be received in the housing;
a bolt adapted to pass through the object and engage the nut whereupon the nut being received in the housing and the bolt fastened relative to the nut, the object is clampingly secured to the surface.