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Patent Searching and Data


Title:
CALIBRATED CRUSH MODULE
Document Type and Number:
WIPO Patent Application WO/2014/064413
Kind Code:
A1
Abstract:
A module (5), designed to respond to a specific compressive force, comprising: a two- part deflection ring (25) consisting of upper and lower components (10, 15); an outer casing portion (30); and a fluid-filled capsule (40) positioned between the lower component (15) of the deflection ring and the outer casing portion, placed between a force-applying component exemplified by, but not confined to, a nut, bolt, screw, rivet or cam-locking handle and the assembly it is designed to tighten. As the required force is reached the capsule ruptures, releasing the fluid.

Inventors:
STEVENS PETER ROMAIN (GB)
Application Number:
PCT/GB2013/051400
Publication Date:
May 01, 2014
Filing Date:
May 28, 2013
Export Citation:
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Assignee:
STEVENS PETER ROMAIN (GB)
International Classes:
F16B31/02; G01L5/24
Domestic Patent References:
WO1984003741A11984-09-27
Foreign References:
JP2005140314A2005-06-02
JPH10281127A1998-10-20
JPH1193929A1999-04-06
DE102010042263A12012-04-12
Attorney, Agent or Firm:
DOWLING, Andrew John (5th Floor Lincoln House,300 High Holborn,London, Greater London WC1V 7JH, GB)
Download PDF:
Claims:
CLAIMS:

1 A module configured to respond to a predetermined compressive force, the module comprising:

a two-part deflection ring, consisting of first and second components, an outer casing portion, and

one or more fluid-filled capsules positioned between the second component of the deflection ring and the outer casing portion,

wherein the module is configured to be placed within a tightenable assembly that requires tightening to the predetermined compressive force, and is configured to release the fluid from the fluid-filled capsules at the point the predetermined compressive force is attained,

wherein the second component comprises one or more radial vent grooves provided on a surface of the second component that faces the fluid-filled capsules when in an installed configuration.

2 A module as in claim 1 , wherein the fluid contained in the capsule gives visual indication that the predetermined compressive force has been attained. 3 A module as in claim 1 or 2, wherein the fluid contained in the capsule is capable of sealing the thread in the assembly to prevent it being loosened accidentally due to vibration.

4 A module as in any preceding claim, wherein the fluid-filled capsules are pre- filled with fluid such that walls of the capsule are in tension.

5 A module as in any preceding claim, wherein the module comprises a plurality of fluid-filled capsules. 6 A module as in claim 5, wherein different capsules may be configured to rupture at different forces.

7 A module as in claim 5 or 6, wherein the plurality of capsules are circumferentialiy distributed between the second component and the outer casing portion. 8 A module as in any preceding claim, wherein the radial vent grooves have a rectangular, triangular, trapezoidal or rounded cross-section when viewed in the radial direction. 9 A module as in any preceding claim, wherein the material from which the second component of the deflection ring is made is selected to provide a particular predetermined compressive force at which the fluid is released.

10 A module as in any preceding claim, wherein the thickness of the second component of the deflection ring is selected to provide a particular predetermined compressive force at which the fluid is released.

1 1 A module as in any preceding claim, wherein the shape and depth of a cavity between the deflection ring and the outer casing portion is selected to provide a particular predetermined compressive force at which the fluid is released.

12 A module as in any preceding claim, wherein the first component and outer casing portion comprise correspondingly angled surfaces. 13 A module as in claim 12, wherein the second component is held between the angled surfaces of the first component and the outer casing portion and wherein the second component flexes from a substantially flat condition to a frustoconical condition upon tightening of the tightenable assembly. 14 A module as in any preceding claim, wherein the outer casing portion or first component comprise a rim circumferentially disposed about a periphery of the outer casing portion or first component, the rim being configured to at least partially surround the second component. 15 A module as in claim 14, wherein one or more holes are provided in the rim.

16 A product, device or assembly comprising the module of any of the preceding claims.

17 A module as described herein, with reference to, and as shown in the accompanying drawings.

Description:
CALIBRATED CRUSH MODULE

FIELD OF THE INVENTION The present disclosure relates to a module, e.g. a crushable module, that particularly, but not exclusively, yields at a predetermined level of compressive force, releasing a substance that visually confirms the correct force has been reached and may additionally lock the thread, preventing accidental loosening. BACKGROUND

Mission-critical structures and assemblies are typically tightened during manufacture and maintenance using a torque wrench or similar device. Such a device responds in some way to the amount of turning force or torque being applied to a threaded component, showing the operator when the required torque has been attained.

The amount of torque required to produce a specific compressive force in a particular assembly may depend on a number of factors including, but not necessarily confined to: the pitch and profile of the thread being tightened; the friction between surfaces that rotate relative to each other during tightening; the characteristics of any lubricant present; and/or the characteristics of any compressible component(s) in the assembly.

Torque is thus an indirect readout of the force in an assembly, and the optimum torque must be calculated by the assembly's designer based on expectations of factors such as those listed above and others.

Torque wrenches also have a tendency to go out of range; such tools used in mission- critical applications often require periodic recalibration. Finally, the fact that an assembly has been tightened to a specific torque will not be apparent for subsequent inspection or verification; a further process is needed, which may itself be prone to error.

Accordingly, it is desirable to mitigate the disadvantages of the use of torque wrenches by responding directly to the force present in an assembly, removing the variables listed above and others, and by obviating the need to periodically check the wrench's accuracy. it is also desirable to provide a means of visually indicating when the assembly has been tightened to the predetermined level of force. It is further desirable to provide a means of sealing the thread so that it does not become loosened over time due to vibration.

STATEMENT OF THE INVENTION According to an aspect of the present invention there is provided a module configured to respond to a predetermined compressive force, the module comprising: a two-part deflection ring, consisting of first and second components, an outer casing portion, and one or more fluid-filled capsules positioned between the second component of the deflection ring and the outer casing portion, wherein the module is configured to be placed within a tightenable assembly that requires tightening to the predetermined compressive force, and is configured to release the fluid from the fluid-filled capsules at the point the predetermined compressive force is attained, wherein the second component comprises one or more radial vent grooves provided on a surface of the second component that faces the fluid-filled capsules when in an installed

configuration.

The fluid contained in the capsule may give visual indication that the predetermined compressive force has been attained. The radial vent grooves may facilitate the flow of the fluid to an outer periphery, thereby aiding the visual indication.

The fluid contained in the capsule may be capable of sealing the thread in the assembly, e.g. to prevent it being loosened accidentally due to vibration.

The fluid-filled capsules may be pre-filled with fluid such that walls of the capsule may be in tension. Alternatively, the fluid-filled capsules may be pre-filled with fluid such that walls of the capsule may not be in tension, e.g. the fluid-filled capsules may be pre-filled to a pressure just before the walls are in tension.

The module may comprise a plurality of fluid-filled capsules. Different capsules may be configured to rupture at different forces. The plurality of capsules may be circumferentially distributed between the second component and the outer casing portion.

The radial vent grooves may have a rectangular, triangular, trapezoidal or rounded cross-section when viewed in the radial direction, e.g. along the radial vent groove. The radial vent grooves may facilitate flexing of the second component.

The material from which the second component of the deflection ring may be made may be selected to provide a particular predetermined compressive force at which the fluid may be released. The thickness of the second component of the deflection ring may be selected to provide a particular predetermined compressive force at which the fluid may be released. The shape and depth of a cavity between the deflection ring and the outer casing portion may be selected to provide a particular predetermined compressive force at which the fluid may be released.

The first component and/or outer casing portion may comprise correspondingly angled surfaces. The second component may be held between the angled surfaces of the first component and the outer casing portion. The second component may flex from a substantially flat condition to a frustoconical condition upon tightening of the tightenable assembly.

The outer casing portion or first component may comprise a rim circumferentially disposed about a periphery of the outer casing portion or first component. The rim may be configured to at least partially surround the second component. One or more holes may be provided in the rim. The holes may line up with the radial vent passages, e.g. thanks to a feature, such as a protrusion and corresponding recess, configured to ensure that they line up. The holes may assist visual indication that the predetermined compressive force has been attained by allowing the fluid to pass through the holes or be viewed through the holes.

The module may be configured to be placed under a non-threaded or threaded tightening device. The module may be configured to be used with a nut, bolt, screw, rivet, cam-locking handle or other force-producing device whether threaded or not. A product, device or assembly may comprise the above-mentioned module. The outer casing portion may be a separate component with respect to the product, device or assembly or the outer casing portion may be integral with a portion of the product, device or assembly.

In a further aspect of the invention there is provided a module, to be placed between a nut or the head of a bolt or screw and the adjacent component of the structure or assembly which is to be tightened, comprising; a two-part deflection ring, an outer casing, and a rupturable fluid-containing capsule positioned in the cavity between the lower surface of the deflection ring and the outer casing; wherein the action of tightening the bolt, nut or screw presses on the deflection ring causing it to distort and encroach on the cavity between the lower surface of the deflection ring and the upper surface of the outer casing, thereby rupturing the capsule and releasing the fluid contained in it.

Embodiments of the invention have the advantage that, by varying the material from which the lower part of the deflection ring is made and/or its thickness, and/or the shape and depth of the cavity between the deflection ring and the outer casing, the force required to rupture the fluid-containing capsule can be varied.

Embodiments of the invention have the further advantage that the release of fluid from the fluid-containing capsule gives a positive indication that the assembly has been tightened to the degree intended by its designer.

Embodiments of the invention have the additional advantage that the incorporation of a further fluid-containing capsule or capsules can give additional functionality including, but not limited to, a visual alert that the assembly has been tightened beyond its intended force, and/or that the assembly has been loosened subsequent to its correct tightening.

Embodiments of the invention also have the advantage that their use is not limited to applications where the mechanism providing the force is a threaded bolt or screw. Instead it can indicate correct force when tightened by an alternative means exemplified by, but not confined to, a rivet or cam-locking handle.

Embodiments of the invention have a yet further advantage that the fluid contained within the capsule can be a thread locking fluid, so that when the fluid is released as well as indicating the optimum force has been reached it will also lock the bolt, nut or screw to its mating thread so as to maintain this optimum force over a long period of time and not creep into a relaxed position.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be described with reference to the

accompanying figures in which:

FIGURE 1 is a plan view of the calibrated crush module.

FIGURE 2 shows the two components of the deflection ring sub-assembly: FIGURE 2A is an underside view of the lower component or washer; FIGURE 2B shows the components in exploded view; and FIGURE 2C shows the components assembled. FIGURE 3 is a cross-sectional elevation of the calibrated crush module: FIGURE 3A shows the components in exploded view; FIGURE 3B is a cross-sectional elevation of the complete module.

FIGURE 4 is a cross-sectional elevation of the complete calibrated crush module located on the assembly onto which it will be tightened and with a bolt in situ: FIGURE 4A shows the assembly prior to tightening; FIGURE 4B shows the assembly fully tightened.

FIGURE 5 is a partial cross-sectional view of the calibrated crush module with the rupturable fluid-filled capsule omitted.

FIGURE 6 is a cross-sectional view of the radial vent grooves viewed in the radial direction. FIGURE 7 is a partial perspective view of the outer casing portion. DETAILED DESCRIPTION

FIGURE 1 shows a plan view of the calibrated crush module 5 according to a first embodiment of the present invention. A first upper component 10 and second lower component 15 form a deflection ring sub-assembly 25. An outer casing 30 comprises a hole 50 in which a bolt, rod or screw (threaded or otherwise) will be positioned as the module is being used.

FIGURE 2 shows deflection ring sub-assembly 25. FIGURE 2A is an underside view of the lower component 15, illustrating radial vent grooves 20 to encourage fluid to escape to the upper surfaces of the module for visual verification of the required force having been reached, although it is to be appreciated that other means of encouraging fluid to escape could be employed. FIGURE 2B shows the upper and lower components 10, 15 of the deflection ring sub-assembly in exploded view. FIGURE 2C shows the components assembled, with the tubular projection of the upper component 10 flared to hold the sub-assembly 25 together while allowing relative rotation of the two components. It is to be appreciated that the sub-assembly could be constructed in alternative ways in order to achieve the same objective. FIGURE 3 shows the components of the calibrated crush module 5. FIGURE 3A is an exploded cross-sectional elevation showing the deflection ring sub-assembly 25, rupturable fluid-filled capsule 40, and outer casing 30. In this embodiment the fluid- filled capsule 40 is toroidal in form, although it is to be appreciated that other shaped capsules could be used. FIGURE 3B is a cross-sectional elevation of the complete calibrated crush module 5. As is depicted, the capsule 40 may be disposed between the lower component 15 and outer casing 30 at a radially inner position, e.g. adjacent to the hole 50. A groove 32 may be formed in the outer casing 30 for receiving the capsule 40. The capsule 40 may additionally be held in place with an adhesive. The upper component 10 and/or outer casing 30 may comprise correspondingly angled surfaces 11 , 31 , which may be angled with respect to a radial plane, e.g. so as to form frustoconical surfaces. The lower component 15 may be held between the angled surfaces 1 1 , 31 of the upper component and the outer casing. The outer casing 30 and/or upper component 10 may comprise a rim or lip

circumferentially disposed about a periphery of the outer casing or upper component. The rim or lip may be configured to at least partially surround the lower component 15. For example, a rim 45 in the form of a cylindrical projection at the top of the outer casing 30 may be formed over to trap the deflection ring sub-assembly 25 by the outer edge of its lower component 15, although it is appreciated that other methods could be employed to fulfil this objective. In the first embodiment the capsule 40 contains a threadlocking fluid such as 3M Scotch-Weld (RTM) Anaerobic Threadlocker TL43, although it is to be appreciated that other fluids could be used.

In the first embodiment the capsule 40 is made of a thin plastic film, but it is to be appreciated that other materials could also be used. For example, the capsule could be formed from a resilient material, such as rubber. Furthermore, in a particular example, the fluid-filled capsules 40 may be pre-filled with fluid such that walls of the capsule may be in tension. Alternatively, the fluid-filled capsules 40 may be pre-filled with fluid such that walls of the capsule may not be in tension, e.g. the fluid-filled capsules may be pre-filled to a pressure just before the walls are in tension.

In the first embodiment a single capsule 40 is used and the capsule may be ring shaped, e.g. in the shape of a toroid such as a torus. However, it is to be appreciated that multiple capsules containing the same or different fluids, e.g. with different colours, could be used. In the case of there being multiple capsules, different capsules may be configured to rupture at different forces. Multiple capsules may be circumferentially distributed between the lower component and the outer casing.

In the first embodiment the parts of the module other than the fluid-filled capsule 40 may be made from metal, although it is to be appreciated that other materials could also be used. FIGURE 4 is a cross-sectional elevation of the complete calibrated crush module 5 located on a product, device or assembly 55 onto which it will be tightened and with a bolt 60 in situ. Although FIGURE 4 shows the outer casing 30 being a separate component with respect to the product, device or assembly 55, it is also envisaged that the outer casing 30 may be integral with the product, device or assembly 55, e.g. such that the outer casing 30 is a portion of the product, device or assembly 55 FIGURE 4A shows the assembly prior to tightening; and FIGURE 4B shows the assembly fully tightened, with the deflection ring having ruptured the fluid-filled capsule.

As depicted in FIGURE 4, the lower component 15 may flex from a substantially flat condition to a frustoconical condition due to the angled surfaces 11 , 31. In use, the module is placed under the nut or the head of a bolt or screw securing an assembly prior to tightening. As the nut, bolt or screw is tightened, force is produced which distorts the lower component of the deflection ring until its upper and lower surfaces are in full contact with the ramped surfaces of the upper component of the deflection ring and the outer casing. At this point the fluid-filled capsule ruptures, releasing its contents.

The degree of tightness required to achieve this condition is controlled by the diameter, thickness and material of the lower component of the deflection ring, and by the profile of the matching ramps on the upper component of the deflection ring and the outer casing. By manipulating these variables, modules can be designed which operate at different compressive forces.

Referring to FIGURE 5, either or both of the angled surfaces 11 , 31 may be curved. In the particular example shown, the angled surface 31 is straight in cross-section and the angled surface 11 is curved in cross-section, e.g. with a convex curve. The curved angled surface 11 may assist in bending the lower component 15.

As further depicted in FIGURE 5, the groove 32 in the outer casing 30 may be shaped, e.g. curved in cross-section, so as to conform to the shape of the capsule 40. Such shaping may assist in holding the capsule 40 in place, e.g. during assembly of the module.

Turning now to FIGURE 6, it will be appreciated that the radial vent grooves 20 may have a rectangular (including square), triangular, trapezoidal, rounded or any other cross-section when viewed in the radial direction. It will also be appreciated that the radial vent grooves 20 may facilitate flexing of the lower component, e.g. as the lower component 15 flexes from a substantially flat condition to a frustoconical condition. With reference to FIGURE 7, one or more holes 33 may be provided in the rim 45. The holes 33 may extend radially though the rim 45 and they may be circumferentially distributed about the rim. The holes 33 may line up with the radial vent passages 20. The alignment of the holes 33 and radial vent grooves 20 may be ensured by virtue of an alignment feature, such as a protrusion and corresponding recess provided on the lower component and outer casing respectively or vice versa. The holes 33 may assist visual indication that the predetermined compressive force has been attained by allowing the fluid to pass through the holes or be viewed through the holes. In the case of a rim being provided on the upper component 10, the holes may also be provided in such a rim. Throughout the description and claims of this specification, the words "comprise" and "contain" and variations of the words, for example "comprising" and "comprises", means "including but not limited to", and is not intended to (and does not) exclude other moieties, additives, components, integers or steps. Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise. Features, integers, characteristics, compounds, chemical moieties or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith.