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Title:
CRIMPING
Document Type and Number:
WIPO Patent Application WO/2012/046163
Kind Code:
A1
Abstract:
A crimping device (10) for crimping the mouth of a metal housing, comprises a support (11), and crimping elements (36) on the support (11). Each crimping element (36) has a front end face (36.2), and a pair of abutment side faces 836.4) located respectively on opposite sides of the end face (36.2). The crimping elements (36) are movable to displace their front end faces (36.2) between extended and retracted configurations. The front end faces (36.2) of the crimping elements (36) collectively define, when the crimping elements (36) are in their extended configuration, a segmented crimping ring having, at its centre, a crimping axis (A1). The device (10) also includes a cam (40) defining a cam surface (40.3), and a connecting element (42) connecting the cam (40) to each crimping element (36). The connecting elements (42) are arranged to displace their associated crimping elements (36) on displacement of the cam (40) such that the front end faces (36.2) of the movable crimping elements (36) are thereby synchronously moved into their extended configuration.

Inventors:
BRAMWELL GAVIN WILLIAM (ZA)
Application Number:
PCT/IB2011/054265
Publication Date:
April 12, 2012
Filing Date:
September 28, 2011
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
AEL MINING SERVICES LTD (ZA)
BRAMWELL GAVIN WILLIAM (ZA)
International Classes:
B21D39/04; F42B3/195; B23P11/00; B25B27/10; B25B27/14
Domestic Patent References:
WO2008056333A12008-05-15
Foreign References:
US0758195A1904-04-26
US1322584A1919-11-25
US4989443A1991-02-05
Attorney, Agent or Firm:
KOTZE, Gavin, Salomon et al. (PO Box 1014, 0001 Pretoria, ZA)
Download PDF:
Claims:
CLAIMS

1 . A crimping device for crimping the mouth of a metal housing, the crimping device comprising

(v) a support;

(vi) a plurality of crimping elements on the support, with each crimping element having a front end face, and a pair of abutment side faces located respectively on opposite sides of the end face, with at least some of the crimping elements being movable to displace their front end faces between extended and retracted configurations and with each crimping element abutting at least one adjacent crimping element such that facing abutment side faces of the crimping elements abut each other when the front end faces of the movable crimping elements are in their extended configuration, the front end faces of the crimping elements collectively defining, when the movable crimping elements are in their extended configuration, a segmented crimping ring having, at its centre, a crimping axis;

(vii) a cam defining a cam surface and which is displaceably mounted to the support; and

(viii) a plurality of connecting elements connecting the cam to the movable crimping elements, one connecting element thus extending between one of the movable crimping elements and the cam, with the connecting elements being arranged to displace their associated movable crimping elements on displacement of the cam such that the front end faces of the movable crimping elements are thereby synchronously moved into their extended configuration.

2. The crimping device according to Claim 1 , wherein the crimping elements are arranged on the support on respective radii of the crimping axis and are thus angularly spaced from each other about the crimping axis, with the movable crimping elements being movable to displace their respective front end faces along their associated radii on displacement of the cam.

3. The crimping device according to Claim 1 or Claim 2, wherein the mounting of the cam on the support is such that the cam is angularly displaceable along an at least partly circular displacement path lying on about the crimping axis.

4. The crimping device according to any one of Claims 1 to 3 inclusive, wherein the cam surface of the cam is directed toward rear ends of the movable crimping elements.

5. The crimping device according to Claim 4, wherein each connecting element is pivotally connected, at respective ends thereof, to the cam and to its associated crimping element by means of cam and crimping element connections respectively, with the cam being displaceable along its arcuate displacement path such that

(iii) at at least one instance of displacement of the cam along its displacement path, associated cam and crimping element connections of respective connecting elements are not in radial register about the crimping axis and the movable crimping elements are in their retracted configuration; and (iv) at at least one other instance of displacement of the cam along its displacement path, associated cam and crimping element connections of respective connecting elements are in radial register about the crimping axis and the movable crimping elements are in their extended configuration.

6. The crimping device according to Claim 5, wherein the cam connections are provided in the cam surface and the crimping element connections are provided in rear ends of the crimping elements.

7. The crimping device according to any of Claims 1 to 6 inclusive, wherein the support comprises a unitary support member to which is mounted the crimping elements, the cam and the connecting elements.

8. The crimping device according to Claim 7, which includes a single cam for all the movable crimping elements and their associated connecting elements, with the cam defining a cam surface which is circular in plan view and which is co-axial with the crimping axis.

9. The crimping device according to any of claims 1 to 6 inclusive, wherein the support comprises a pair of opposed jaws, with a separate cam and associated crimping elements and connecting elements being provided for each jaw.

Description:
CRIMPING

THIS INVENTION relates, broadly, to crimping. More particularly, it relates to the crimping of detonators for detonating explosives. Still more particularly, the invention relates to a device for crimping the mouth of a metal housing, specifically a metal detonator housing, around an initiating element, such as a shock tube, fuse or electrical lead, protruding into the housing through the mouth.

In crimping metal housings, and particularly mouths thereof, it is desirable for a uniform circumferential crimp to be achieved. Such a crimp generally needs to be circular, particularly when the metal housing is also circular. The Applicant is aware of crimping devices, such as that set forth in WO 2008/056333, that seek to achieve such uniform circumferential crimping. However, in the Applicant's experience, very few, if any, such devices are truly successful in this regard, usually exceeding an acceptable crimp ovality. It will be appreciated that an unacceptable crimp ovality impacts negatively on the tightness with which the initiating element is secured to the housing and also on the integrity of the seal that is formed between the housing and the initiating element by the crimp.

The present invention seeks to provide for the crimping of the mouth of a metal housing, bearing in mind the abovementioned difficulties in achieving a uniform circular crimp in a metal housing. In accordance with one aspect of the invention, there is provided a crimping device for crimping the mouth of a metal housing, the crimping device comprising

(i) a support;

(ii) a plurality of crimping elements on the support, with each crimping element having a front end face, and a pair of abutment side faces located respectively on opposite sides of the end face, with at least some of the crimping elements being movable to displace their front end faces between extended and retracted configurations and with each crimping element abutting at least one adjacent crimping element such that facing abutment side faces of the crimping elements abut each other when the front end faces of the movable crimping elements are in their extended configuration, the front end faces of the crimping elements collectively defining, when the movable crimping elements are in their extended configuration, a segmented crimping ring having, at its centre, a crimping axis;

(iii) a cam defining a cam surface and which is displaceably mounted to the support; and

(iv) a plurality of connecting elements connecting the cam to the movable crimping elements, one connecting element thus extending between one of the movable crimping elements and the cam, with the connecting elements being arranged to displace their associated movable crimping elements on displacement of the cam such that the front end faces of the movable crimping elements are thereby synchronously moved into their extended configuration. As to the cam: In this specification, the term "cam" is preferably to be understood to mean, broadly, any component of the device or portion thereof which is subject to angular displacement itself but which effects linear displacement of the movable crimping elements to which the cam is operatively connected by the connecting elements. The connecting elements themselves are not regarded as constituting cams within this meaning. The cam can therefore be regarded as a crimping element displacement component or member that translates its own angular displacement into linear displacement of the crimping elements by means of the connecting elements.

Further, as to the cam: It is envisaged that the device may, in certain embodiments thereof as described hereinafter, have more than one cam, with each cam being operatively associated with and connected, by means of the connecting elements, to a number of the crimping elements. Thus, any reference hereinafter to "the cam" should be construed as not limiting the invention to a configuration of the device having only a single cam, but providing for the possibility that more than one cam may be provided.

As to the crimping axis: The crimping axis is, strictly speaking, defined only when the movable crimping elements are in their extended configuration in which the crimping ring is defined. However, even when the crimping ring is not defined and the movable crimping elements are in their retracted configuration, a hypothetical crimping axis will still exist in the location where the crimping axis stands to be defined, which hypothetical crimping axis becomes defined as the crimping axis when the movable crimping elements are in their extended configuration.

The metal housing may, in particular, be a metal detonator housing into which intrudes an initiating element such as a shock tube, fuse or electrical lead. Crimping of the mouth of the metal detonator housing thus serves to crimp the housing mouth around the intruding initiating element, thereby securing the initiating element in position relative to the housing mouth. The segmented crimping ring may define, at its centre, a crimping passage, preferably a circular cylindrical crimping passage, provided by the front end faces of the crimping elements. The crimping passage may thus be for holding a crimped mouth of a detonator, the mouth having been crimped by the synchronous displacement of the front end faces of the movable crimping elements into their extended configuration in forming the crimping passage.

The crimping elements may be elongate and roughly oblong, tapering in width toward their front end faces along their abutment side faces. Preferably, each crimping element has, in addition to its front end face and abutment side faces, a rear end face and two rearwardly disposed side faces, with the rearwardly disposed side faces being so disposed in relation to the abutment side faces and connecting the abutment side faces to the rear end face. The rearwardly disposed side faces are typically parallel to each other, with the abutment side faces thus being inclined relative to the rearwardly disposed side faces. The front end faces of the crimping elements may typically be parallel to the crimping axis and may be concavely curved in plan view outline. It will be appreciated that such concave curvature results in the segmented crimping ring, when formed, being circular in plan view outline, with each front end face providing an arc of the circular outline of the crimping ring. In the extended configuration of the movable crimping elements, the front end faces of adjacent crimping elements may align flush with each other, thereby to define the segmented ring.

The front end faces of the crimping elements may also be toothed, thus each being provided with a number of tooth formations which protrude therefrom and assist crimping of the detonator housing.

The number of crimping elements may be selected by routine experimentation bearing in mind difficulties in obtaining a desirably circular segmented crimping ring when there are too few crimping elements, and difficulties associated with expense and complexity of construction when there are too many crimping elements.

It is, however, expected that the number of crimping elements may be in the range of 4 to 16. Typically, the number of crimping elements may be in the range of 6 to 10, with the preferred number, in certain embodiments of the invention, being 6.

The crimping elements, or at least the front end faces thereof, may be angularly, preferably equiangularly, mounted relative to each other about the crimping axis. In other words, the crimping elements, or at least their front end faces, may be arranged on the support on respective radii of the crimping axis, with the movable crimping elements being movable to displace their respective front end faces along their associated radii on displacement of the cam. The radii may then be equiangularly spaced from each other about the crimping axis. Typically, the angular spacing between adjacent crimping elements, and thus between adjacent radii on which such crimping elements are provided, about the crimping axis may be 360° divided by the total number of crimping elements. Thus, in the preferred embodiment in the invention in which 6 elements are provided, the angular spacing between adjacent crimping elements, and thus between the radii of the crimping axis on which the crimping elements are provided, may be 60 ° .

The crimping elements may thus be so mounted for displacement, preferably linear or radial displacement, along said radii between their extended and retracted configurations. It will be appreciated that, when displaced into the extended configuration, the front faces of the crimping elements may thus, collectively and synchronously by operation of the cam(s), concentrically converge towards and about the crimping axis along said radii, thereby to form the crimping ring.

In a preferred embodiment of the invention, each crimping element, or at least the front end face of each crimping element, may be diametrically opposite at least one other crimping element, or at least a front end face thereof, about the crimping axis and may remain so diametrically opposite when the front end faces are synchronously displaced into the extended configuration and into the retracted configuration about the crimping axis.

Preferably, all of the crimping elements are movable with all of their front end faces therefore being synchronously displaceable into the extended configuration by displacement of the cam(s). Alternatively, at least one of the crimping elements may be fixed and hence immovably connected to or integral with the support. It will be appreciated that, in such a case, the fixed element may typically be fixed to the support such that its front end face is defined effectively in an extended configuration in relation to the movable crimping elements such that, when the movable crimping elements are displaced into their extended configuration, the front end face(s) of the immovable crimping element(s) define/s a part of the segmented crimping ring. The crimping elements, particularly the movable crimping elements, may be arranged in one or more cavities provided therefor in the support, in which cavities the movable crimping elements are displaceably mounted for displacement of their front end faces into the extended configuration. Preferably, the crimping element cavities define crimping element passages for each of the movable crimping elements. The crimping element passages would then extend radially from the crimping axis and thus be angularly arranged or defined about the crimping axis, in the one or more crimping element cavities. The movable crimping elements would then be provided in the passages, being displaceable along the passages to displace their respective front end faces into their extended configuration.

The crimping element passages may be arranged or defined in identical positions, or rather on identical radii of the crimping axis as the radii on which the movable crimping elements, or at least the front end faces thereof, are provided. The passages may typically be defined by spacing elements provided in the crimping element cavities and which are connected to or integral with the support and thus space the crimping elements from each other in the crimping element cavities.

In being moved into the extended condition, a crimping element, or at least the front face thereof, may move out of its associated passage, if the crimping element is not mounted with its front end face outside the passage, to allow abutment of adjacent crimping elements with each other so as to define the crimping ring.

The cam surface(s) of the cam(s) may have a complemental profile to a general profile in which the crimping elements, or at least the front end faces of the crimping elements, specifically the movable crimping elements, are generally arranged relative to each other. More specifically, when the crimping elements, or at least the front end faces thereof, are angularly arranged relative to each other about the crimping axis, as is hereinbefore described, the cam surface of the, or each, cam may have an at least part-circular, i.e. possibly circular, profile. The mounting of the cam on the support may be such that the cam is angularly displaceable along an at least part-circular, i.e. possibly circular, displacement path about the crimping axis. Preferably, the mounting of the cam on the support is such that the cam surface of the cam is directed toward rear ends of the movable crimping elements. The, or each, cam may therefore be displaceable along its displacement path so as to move the cam's cam surface circumferentially about the crimping axis and across the respective radii along which the crimping elements are typically mounted. The displacement path of the, or each, cam may typically be complementally shaped to the cam surface of the, or each, cam, thus preferably being at least part-circular.

In a preferred embodiment of the invention, the, or each, cam may be mounted in an associated cam cavity provided therefor in the support, which cam cavity defines the cam displacement path. Typically, the, or each, cam cavity is defined in the support operatively rearwardly/outwardly relative to, i.e. behind, the crimping elements of its associated cam, thereby allowing for the cam surface of the, or each, cam to be directed toward the rear ends of its associated crimping elements. The crimping element cavities of the crimping elements that are associated with a particular cam would typically extend into the cam cavity of their associated cam, with the cam cavity thus effectively forming part of the crimping element cavity and enabling connection of the crimping elements to their associated cam along the cam surface thereof. Preferably, the, or each, cam cavity may be at least partly defined by an intermediate wall provided in the support, through which intermediate wall the crimping element cavities or passages as hereinbefore described extend into their associated cam cavities. The intermediate walls preferably have complemental profiles to the profile of the cam surface of their associated cams, such that the cam surfaces of their associated cams may respectively be moved along the intermediate walls by displacement of the cams. Typically, the intermediate wall is defined by operatively rear ends of the spacing formations, when these are provided in the crimping element cavities to define the crimping element passages.

The, or each, cam may have a control member by which displacement of the cam along the displacement path can be controlled or manipulated. The control member may typically be in the form of a radial projection of the cam which projects radially outwardly from an operatively radially outer face of the cam, through an aperture or slot provided therefor in the support, the control member thus projecting beyond outer extremities the support. When more than one cam is provided, the cams may be configured, or operatively associated with each other, for synchronized angular displacement, translating into synchronised linear displacement of the crimping elements with which the cams are respectively associated. Each connecting element may be pivotally connected, at respective ends thereof, to its associated cam and to its associated crimping element by means of cam and crimping element connections respectively, with the cam being displaceable along its at least part circular displacement path such that

(i) at at least one instance of displacement of the cam along its displacement path, associated cam and crimping element connections of respective connecting elements are not in radial register about the crimping axis and the movable crimping elements are in their retracted configuration; and

(ii) at at least one other instance of displacement of the cam along its displacement path, associated cam and crimping element connections of respective connecting elements are in radial register about the crimping axis and the movable crimping elements are in their extended configuration.

The cam connections may be provided in the cam surface and the crimping element connections may be provided in rear ends of the crimping elements.

In a particular embodiment of the invention, the connecting elements may be in the form of pawls which are pivotally mounted both to their associated cam and to their associated crimping elements at respective cam and crimping element connection points that are provided by the crimping element connections. Typically, each pawl may be mounted to respective cam and crimping element pawl engagement formations, constituting the crimping element connections and thus also providing the crimping element connection points. It will be appreciated that, typically, each cam engagement formation will have a corresponding crimping element engagement formation provided by an associated crimping element, with an equal number of cam engagement formations and crimping element engagement formations being provided. Preferably, the cam pawl engagement formations may be defined in their associated cam such that they are spaced, preferably equidistally, from each other along the cam surface of their associated cam so as to allow the formations simultaneously to be brought into radial register about the crimping axis with their associated crimping element engagement formations.

In a preferred embodiment of the invention, both the cam and crimping element connections, or pawl engagement formations when the crimping elements comprise pawls as hereinbefore described, may be in the form of slots which are defined respectively in the cam surface of the or each cam and in rear end face of each movable crimping element. An equal number of cam slots, of course, would be provided to the number of movable crimping elements that are provided, as also indicated hereinbefore.

Typically, each connecting element, or pawl, is elongate, having a longitudinal axis and opposed operatively radially inner or proximal and operatively radially outer or distal end portions that are complementally shaped respectively to the crimping element and cam connections or engaging formations, more particularly being complementally shaped to the crimping element slots and the cam slots, so as to cooperate pivotally therewith. Each of these radially inner and radially outer end portions may define a pivot axis along with their associated crimping element and cam engaging formations, which pivot axes are parallel to the crimping axis, with the connecting elements thus being pivotally connected both to their associated cams and to their associated crimping elements.

It will be appreciated that when associated crimping element and cam connections, by which a connecting element connects a crimping element to its associated cam, are not in radial register about the crimping axis, the longitudinal axis of the connecting element will also not be in radial register with the radius on which the crimping element is located, considering that the connecting elements extend longitudinally between their associated cam and crimping element connections. Angular displacement of the cam along its displacement path would, however, bring associated cam and crimping element connections of the respective connecting elements into radial register, resulting in simultaneous pivotal angular displacement of the connecting elements, and thus of their longitudinal axes, in the same direction in which the cam is being displaced. During such displacement, the radially outer ends of the connecting elements would remain at a fixed radial distance from the crimping axis, travelling along the displacement path of their associated cam(s). The radially inner ends of the connecting elements, however, would not travel along the cam displacement path, being connected to their associated crimping elements that are arranged for linear, not angular, displacement. Thus, as a cam connection of a particular connecting element is brought into radial register with its associated crimping element connection, the operatively inner end of the connecting element is moved into the crimping element cavities of their associated crimping elements, thereby causing or urging the crimping element to move radially linearly inwardly and displace its front end face into the extended configuration. Thus, when the front end faces of the crimping elements are in the retracted configuration, the longitudinal axes of the connection elements may be offset, typically all at equal angles, from the radius of the crimping axis on which its associated crimping element, or at least the front end face thereof, is mounted. By displacing the cams angularly along their displacement paths, the connecting elements are thus also angularly displaced with the longitudinal axes thereof thus being brought into radial alignment or register with said radius associated with its associated crimping element. When the cams are displaced such that the longitudinal axes of the connecting elements are aligned with the respective radii on which their associated crimping elements are defined, the connecting elements may extend a maximum distance into the crimping element cavities of their associated crimping elements, with the crimping elements having been synchronously moved into the extended configuration.

Typically, angular displacement of the cams about the crimping axis results in equal angular displacement of the longitudinal axes of the connecting elements. Accordingly, an angle at which the longitudinal axes of the connecting elements may be typically be offset from the respective radii of the crimping axis on which their associated crimping elements may be mounted when the crimping elements are in the retracted configuration may, at most, be equal to the displacement angle through which the cam surfaces may be displaced about the crimping axis along their respective displacement paths. Preferably, however, said angles of offset may be a fraction, typically half, of the displacement angles, such that displacement of the cams through the displacement angles results, initially, in the longitudinal axes being brought into alignment with their associated radii of the crimping axis and are subsequently, by continued displacement of the cams along their respective displacement paths through the displacement angle, again moved out of alignment with said radii. Thus, in such a case, by displacing the cams along the whole of their respective displacement paths, i.e. through their entire displacement angles, the crimping elements are, initially, moved operatively radially inwardly into the extended configuration and, subsequently, moved operatively radially outwardly towards the retracted configuration. The support may, in one embodiment of the invention, comprise a unitary support member to which is mounted the crimping elements, the cam and the connecting elements. In this embodiment, the device preferably includes a single cam for all the movable crimping elements and their associated connecting elements, the cam defining a cam surface which is circular in plan view outline and is co-axial with the crimping axis.

Alternatively, the support may include a pair of opposed jaws, with a separate cam and associated crimping elements and connecting elements being provided for each jaw. In such a case, at least one of the jaws may be movable relative to the other, being reciprocally mounted so that at least one of the jaws is reciprocally movable alternately towards and away from the other jaw to bring the jaws successively into contact with each other along respective jaw abutment faces and then to space the jaws apart from each other.

The crimping elements of each jaw may, in their extended configuration, define a segmented crimping face so that the crimping faces of the jaws together form the segmented crimping ring. The crimping faces may thus be part-circular, conveniently semi-circular, in plan view outline. It will be appreciated that, in such a case, the crimping ring may typically be circular in cross-sectional outline.

Each jaw may comprise a more or less elongated rectangular flattened bar, conveniently of metal, the bar being longer than it is wide and wider than it is thick, so that it has a pair of major faces spanning its length and width, a pair of side faces spanning its length and thickness, and a pair of end faces spanning its width and thickness. The jaws may be reciprocally mounted with the abutment faces thereof facing each other. Typically, one of the side faces of each of the jaws may constitute the abutment faces of the jaws with the jaws thus being mounted with one pair of side faces thereof facing each other. Each jaw may have an equal number of crimping elements mounted thereto. The number of crimping elements in each jaw may be selected by routine experimentation bearing in mind difficulties in obtaining a desirably circular toothed passage when the jaws are tightly closed, when there are too few crimping elements, and difficulties associated with expense and complexity of construction, when there are too many crimping elements.

The number of crimping elements in each jaw may therefore be in the range of 2 to 8. Typically, the number of crimping elements in each jaw may be in the range of 3 to 5, preferably 3. More particularly, each jaw may have an odd number of crimping elements, for example 3, 5 or 7, the preferred number again being 3, so that there are, in each jaw, a central element and one or more additional crimping elements on each side of the central element.

Typically, the angular spacing between adjacent crimping elements in each jaw may be 180 ° divided by the number of crimping elements in the jaw. Thus, in the preferred embodiment of the invention in which each jaw has three crimping elements, the angular spacing between adjacent crimping elements in each jaw, and thus between the radii of the crimping axis on which the crimping elements are provided, may be 60 ° .

In being moved into the extended condition when the jaws are in abutment with each other along the abutment faces thereof, adjacent crimping elements in the different jaws may also abut each other along side faces thereof, thereby to define the crimping ring. When the jaws are in abutment with each other along the abutment faces thereof, an angular spacing between adjacent crimping elements in different jaws may be such that all of the crimping elements, collectively, are equiangularly spaced about the crimping axis.

The crimping element cavities may be defined in, and may thus extend inwardly into, their associated jaws from the abutment face of the respective jaws, terminating at respective rear walls in the jaws. Typically, the crimping element cavities may also extend from one major face their associated jaws and terminate short of the other major face of the jaw, each cavity thereby defining a floor. The major faces of the jaws in which the cavities are defined may, in such a case, typically be closed by a cover plate, which acts to hold the crimping elements in their associated jaws. The cavities may typically be part-circular, preferably semicircular, in outline plan view cross sectional outline, i.e. perpendicular to major faces of the jaws, thus extending radially from and angularly about the crimping axis. The cavities together, when the jaws are in abutment with each other along their abutment faces, may define a cavity having a circular outline and being co-axial with the crimping axis.

When the support comprises two opposed jaws, each jaw may have associated therewith at least one cam. The cams associated with the respective jaws may, in a preferred embodiment of the invention, each have a body having a generally arcuate, or part-circular, profile, thus defining oppositely facing typically complementally curved, concave and convex faces, the concave face of each cam constituting the cam surface of its associated cam. The cam surface may typically have a part-circular profile which is, preferably, not semi-circular, thus not defining a circle with a mirror image thereof. More particularly, the cam surface may be defined as an arch of the crimping axis having an included angle, between radii of the crimping axis which define the arch between them, which included angle is smaller than 180 ° , e.g. 162 ° . The cams may be mounted in respective cavities provided therefor in the jaws. Typically, the cam cavities are defined in their associated jaws operatively rearwardly relative to the crimping elements of their associated jaws. The crimping element cavities may typically extend into their associated cam cavities, with the cam cavities thus effectively forming part of their associated crimping element cavities and enabling connection of the crimping elements to their associated cams along the respective cam surfaces thereof. Preferably, the cam cavities may each be at least partly defined by an intermediate wall provided in the jaws, through which intermediate wall the crimping element cavities extend into their associated cam cavities, the intermediate walls preferably having complemental profiles to the profile of the cam surface of their associated cams, such that the cam surfaces may be respectively moved along their associated intermediate walls by displacement of the cam. Typically, the intermediate wall is defined by operatively rear ends of the spacing formations, when these are provided in the jaws. The displacement paths defined by the cam cavities in the jaws may typically be part-circular and thus complemental to the cam surfaces of the cams. More particularly, the displacement path may be defined as an arch of the crimping axis having an included angle, between radii of the crimping axis which define the arch between them, which is at least greater than the included angle of an arch defining the cam surface of its associated cam, thereby to define the displacement path in a complemental fashion to the bodies of the cams, but of greater arcuate or part-circular length than the cam bodies. Preferably, the displacement path is semicircular, the included angle of radii enclosing the arch defining the displacement path thus being 180 ° .

It will be appreciated, that a displacement angle about the crimping axis through which the cam surfaces are, in use, displaceable along the displacement paths may typically be the difference between the included angle of the arch defining the displacement path and the included angle of the arch defining the cam surface. Said angle may be less than 180°, typically 18°.

Preferably, each jaw may be provided with one cam, all of the displaceable crimping elements in the jaws then being connected to their associated cam. Alternatively, each jaw may be provided with a plurality of cam elements, with each cam element being connected to at least one displaceable crimping element with the cam elements collectively defining the cams.

The support may include a detonator housing receiving aperture or passage, co-axial with the crimping axis, in which a detonator housing that is to be crimped may be received prior to crimping and may be retained whilst being crimped.

In use, when the support comprises a pair of opposed jaws, the jaws may initially be spaced apart from each other, with the crimping elements in the retracted configuration, so as to allow a detonator housing which is to be crimped to be positioned between abutment faces of the jaws in a position concentric with the crimping axis. Typically, positioning of the crimping element between the jaws may be achieved by means of a conveyor system.

Once the detonator housing has been positioned between the jaws, in the receiving passage, by the conveyor, the jaws may be brought into abutment with each other along the abutment faces thereof such that the detonator housing is secured in position between the jaws.

After the jaws have been brought into abutment with each other, the cams are synchronously displaced along their respective displacement paths and through their respective displacement angles so as to move the crimping elements synchronously into the extended configuration to form the crimping ring about the detonator housing and engage the detonator housing synchronously, thereby radially crimping the detonator housing uniformly about the circumference thereof.

Continued displacement of the cams along their displacement paths results in the crimping elements being moved back towards the retracted configuration, thereby disengaging the now crimped detonator housing.

The jaws are subsequently spaced apart from each other so as to release the crimped detonator housing and allow the crimped housing to be removed from between the jaws to allow for a succeeding detonator housing to be positioned between the jaws and be crimped in identical fashion to the preceding detonator housing.

When, however, the support comprises a unitary support member as hereinbefore described, a detonator housing which is to be crimped may be inserted into the receiving passage either from below or from above the support block such that it is co-axial with the crimping axis. Thereafter, crimping of the detonator housing may be effected in substantially the same manner as in which it is effected when the support comprises two opposed jaws as hereinbefore described, when the jaws are in abutment. Thus, the cam is displaced along its displacement path and through its displacement angle so as to move the crimping elements synchronously into the extended configuration to form the crimping ring about the detonator housing and engage the detonator housing synchronously, thereby radially crimping the detonator housing uniformly about the circumference thereof. Continued displacement of the cam along its displacement path results in the crimping elements being moved back towards the retracted configuration thereby disengaging the crimped detonator housing. The crimped detonator is now allowed housing to be removed from or exit the receiving passage and allow a subsequent detonator housing to enter the receiving passage in order to be crimped.

The invention will now be described by way of example only with reference to the following diagrammatic drawings.

In the drawings: FIGURE 1 shows a three-dimensional perspective view of one embodiment of a crimping device in accordance with the invention;

FIGURE 2a shows an exploded three-dimensional view of the device of Figure 1 ;

FIGURE 2b shows a three-dimensional perspective view of a crimping element of the device of Figures 1 and 2;

FIGURE 2c shows a three-dimensional perspective view of a connecting element of the device of Figures 1 and 2;

FIGURE 3 shows in plan view the crimping device of Figures 1 and 2 in an initialisation configuration, i.e. at initialisation of a crimping sequence for crimping a detonator housing;

FIGURE 4 shows a plan view of the crimping device of Figures 1 through 3 in a detonator housing securing configuration;

FIGURE 5 shows a plan view of the crimping device of Figures 1 through 4 in a crimping configuration; FIGURE 6 shows a plan view of the crimping device of Figures 1 through 5 in a crimped detonator housing disengaging configuration;

FIGURE 7 shows a plan view of the crimping device of Figures 1 through 6 in a crimped detonator housing release configuration;

FIGURE 8 shows, in plan view, another embodiment of a crimping device in accordance with the invention;

FIGURE 9 shows, in plan view, the crimping device of Figure 8 in a detonator housing crimping configuration;

FIGURE 10 shows, in plan view, the crimping device of Figures 8 and 9 in a detonator housing disengaging configuration;

FIGURE 1 1 shows a cross sectional view of a detonator housing crimped by a prior art crimping device, particularly the device described in WO 2008/056333;

FIGURE 12 shows a cross sectional view of a detonator housing crimped by the device of Figures 8 through 10; and

FIGURE 13 shows a plot of the results of pull-out tests conducted on shock tubes mounted to detonator housings by means of a crimper according to the invention.

Referring to the drawings, and in particular to Figure 1 , reference numeral 10 generally indicates a crimping device in accordance with the invention for crimping the mouth of a metal detonator housing 34 (the housing 34 only being shown in Figures 3 through 7).

The device 10 has a support 1 1 comprising two opposed jaws 12A, 12B, each having a generally rectangular cross-sectional profile defined by opposed major faces 14A.1 , 14A.2 / 14B.1 , 14B.2, opposed side faces 16A.1 , 16A.2 / 16B.1 , 16B.2 and opposed end faces 18A.1 , 18A.2 / 18B.1 , 18B.2.

The jaws 12A, 12B are mounted such that the side faces 16A.1 , 16B.1 thereof are directly opposite and facing each other and are spaced apart by a spacing "S". The jaws 12A, 12B are thus in an open configuration relative to each other. The spacing "S" is sufficient to allow a series of detonator housings (such as the housing 34) which are to be crimped by the device 10 to pass between the jaws 12A, 12B in a direction parallel to the facing side faces 16A.1 , 16B.1 of the jaws 12A. 12B.

Although not illustrated as such, it is to be understood that both jaws 12A, 12B are displaceably mounted to a reciprocating mechanism, or caliper, for reciprocal displacement such that the jaws 12A, 12B can selectively be brought into abutment with each other along the facing side faces 16A.1 , 16B.1 thereof, thereby to assume a closed configuration as is illustrated in Figures 4 through 6, and can subsequently be spaced away from each other, thereby to reassume the open configuration. The direction of reciprocation of the jaws 12A, 12B is thus normal to the facing side faces 16A.1 , 16B.1 . It will be appreciated that the facing side faces 16A.1 , 16B.1 thus effectively define abutment faces of the jaws 12A, 12B.

In other embodiments of the invention only one of the jaws 12A, 12B may be reciprocally mounted, with the other jaw thus being fixed or stationary. The reciprocating mechanism is typically operated hydraulically. However, it will be appreciated that the jaws 12A, 12B may, in other embodiments of the invention, be movable by a pneumatic reciprocating mechanism or by a mechanical reciprocating mechanism such as a crank.

A plurality of detonator housings (such as the housing 34) which are to be crimped by the device 10 are, in the present example, carried past the jaws 12A, 12B by a conveyor mechanism (not shown) which is situated below the jaws 12A, 12B, with the detonator housings projecting upwardly from the conveyor mechanism to present their mouths at a desired elevation between the facing side faces 16A.1 , 16B.1 of the jaws 12A, 12B. The conveyor mechanism is configured to move a succession of detonator housings intermittently in a direction parallel to the facing side faces 16A.1 , 16B.1 when the jaws 12A, 12B are sufficiently spaced apart individually to hold one detonator housing stationary between the jaws 12A, 12B at a time so that the detonator housings may be crimped individually by displacement of the jaws 12A, 12B into a crimping configuration (as is hereinafter described). Thus, only one of the detonator housings will be located between the facing side faces 16A.1 , 16A.2 of the jaws 12A, 12B at a time, the spacing between and/or speed of movement of succeeding detonator housings by the conveyor mechanism being selected accordingly. The movement of detonator housings will also be appropriately synchronized with the reciprocation of the jaws 12A, 12B so that the detonator housings are moved to be individually located between the jaws 12A, 12B only when the jaws 12A, 12B are sufficiently spaced apart and thus in the open configuration. Referring now also to Figures 2A through 2C, each jaw 12A, 12B has, in its facing side faces 16A.1 , 16B.1 , a cavity which is semi-circular in plan view, the cavities generally being indicated by reference numeral 20 (and only being shown in exploded view in relation to the jaw 12A).

The semi-circular cavities 20 have equal radii and are symmetrical about a plane parallel to the side faces 16A.1 , 16B.1 , thus together defining a cavity of circular outline when the jaws are in abutment along the facing side faces 16A.1 , 16B.1 thereof, i.e. when in the closed configuration.

The cavities 20 are open at the upper major faces 14A.1 , 14B.1 of their associated jaws 12A, 12B and terminate at respective rear walls 22 and floors 24 in their associated jaws 12A, 12B. The cavities 20 also extend through the operatively rear side faces 16A.2, 16B.2 of their associated jaws 12A, 12B along respective passages 26, the passages 26 having generally rectangular side-view outlines and oblique side walls 26.1 which incline inwardly in plan view outline, the passages 26 thereby each having a tapering appearance in plan view normal to the major faces 14A.1 , 14B.1 of the jaws 12A, 12B. The floors 24 each has a semi-circular cutout 30 in front edges 32 thereof (see Figure 3), the cutouts 30 being oppositely disposed in their associated jaws 12A, 12B and being symmetrical about a plane parallel to the side faces 16A.1 , 16B.1 . The cutouts 30 together define a detonator housing securing or receiving ring with a circular cross-section which is concentric or co-axial with the circular cavity defined by the cavities 20 when the jaws 12A, 12B are in abutment with each other in the closed configuration. In use, a detonator housing 34 (see Figures 3 to 7) which is to be crimped by the device 10 is positioned such that when the jaws 12A, 12b are in abutment, at least a mouth of the housing 34 protrudes through the ring which is defined by the cutouts 30 together, the housing 34 then being laterally secured between the jaws 12A, 12B in the cutout ring when the jaws are in the closed configuration (see, in particular, Figure 4).

Three crimping elements 36 are mounted in series the part-circular cavity 20 of each jaw 12A, 12B, each jaw 12A, 12B thus having a central crimping element which is flanked on either side thereof by one outer crimping element. The crimping elements 36 are mounted in their associated jaws 12A, 12B in respective passages 35 defined therefor in the cavities 20 by generally wedge-shaped spacing formations 38 which are integrally formed with their associated jaws 12A, 12B. As is illustrated more clearly in Figure 2b, each crimping element 36 has a pair of opposite sides 36.1 , providing rearwardly disposed side faces which are straight and parallel. The sides 36.1 of the crimping elements 36 each terminate in respective forwardly disposed abutment side faces 36.4, along which the crimping element 36 tapers in plan view. The abutment side faces 36.4 terminate at concavely curved front end faces 36.2 of their associated crimping elements 36. The front end faces 36.2 are toothed and each has a plurality of tooth formations which extend longitudinally along the front end faces 36.2 in two grouped arrangements 36.3, one being provided above the other. Each crimping element also provides upper and lower faces 36.5 and has a rear end portion 36.6. Each crimping element 36 defines a longitudinal axis "B" parallel to sides 36.1 thereof (see Figures 3 to 6), the crimping elements 36 being longitudinally displaceably mounted in their associated passages 35 such that the end faces 36.2 of the elements 36 can be moved in a direction parallel to the longitudinal axes "B" of their associated crimping elements 36 between an extended, or crimping, configuration, in which, as illustrated in Figure 5, an abutment side face 36.4 of each element 36 abuts an abutment side face 36.4 of at least one adjacent element 36 in the same jaw 12A, 12B, thereby arranging the front end faces 36.2 of adjacent elements 36 flush with each other such that the front end faces 36.2 of the crimping elements 36 of in each jaw together define respective semi-circular segmented crimping faces with adjacent abutment faces 36.4.

The segmented crimping faces of the jaws 12A, 12B together, when the jaws 12A, 12B are in abutment along the facing side faces 16A.1 , 16B.1 thereof, form a segmented crimping ring 17 of circular outline (see Figure 5) with adjacent crimping elements 36 in different jaws 12A, 12B also being in abutment. The crimping ring 17 is concentric or co-axial with the ring defined by the cutouts 30 together, and thus also with the circular cavity defined by the cavities 20 together. The crimping ring 17 defines a central crimping axis "A" (see Figure 5) which is parallel to the front end faces 36.2 of the crimping elements 36. It will be appreciated that the crimping axis "A" is also a central axis of both the cutout ring and the circular cavity, when these are defined. The central crimping axis "A" is, of course, only defined when the jaws 12A, 12B are in the closed configuration and the front faces 36.2 of the crimping elements 36 are in the extended configuration. In view hereof, it should be noted that any reference to positions of components of the device 10 in relation to the crimping axis "A" should thus be regarded as being so in relation to the crimping axis at least when the crimping axis "A" is so defined. However, nonetheless, the crimping axis "A" exists as a hypothetical crimping axis "ΑΓ when the jaws 12A, 12B are in the open configuration and the crimping elements 36 are in the retracted configuration.

The crimping elements 36, and therefore also the passages 38, are equiangularly disposed relative to each other in the part-circular cavities 20 about the crimping axis "A", with inward projections of the longitudinal axes "B" of the crimping elements converging towards and intersecting each other at the crimping axis "A", when the jaws 12A, 12B are in the closed configuration. The longitudinal axes "B" of the crimping elements thus constitute respective equiangularly spaced radii of the crimping axis "A".

Included angles "C" between the longitudinal axes "B" of adjacent crimping elements 36 about the crimping axis "A" are therefore equal, as well as included angles "C1 " (see Figure 4) between the longitudinal axes of adjacent crimping elements 36 in different jaws 12A, 12B, when the jaws 12A, 12B are in the closed configuration. It will be appreciated that the crimping elements 36 are therefore equiangularly disposed in the circular cavity defined by the semi-circular cavities 20 of the jaws 12A, 12B, with the longitudinal axes "B" of the crimping elements 36 being at angles "C" and "C1 " of 60 ° relative to each other about the crimping axis "A". Each jaw 12A, 12B is further provided with a cam 40 comprising a body 40.1 having an arcuate, part-circular plan view profile, the bodies 40.1 of the cams 40 thus having opposed concave operatively inner and convex operatively outer faces 40.3, 40.4. The operatively inner face 40.3 of each cam 40 constitutes what is hereinafter referred to as a "cam surface", along which angular displacement of the cam 40 is translated into linear reciprocating motion of the crimping elements 36 associated with and connected to the respective cams 40 in the fashion hereinafter described. Each cam 40 further has a manipulating member 40.2 which projects operatively radially outwardly or rearwardly from the operatively outer face 40.4 of the bodies 40.1 of the cams 40.

It is important to note that the bodies 40.1 of the cams are not semicircular in profile. The operatively inner and outer faces 40.3, 40.4 of the cams have curvatures complemental to respective arches of an included angle between radii of concentric or co-axial circles including the arches, the included angle being smaller than 180 ° , more particularly 162 ° in the illustrated embodiment. The cam surfaces 40.3 of the bodies 40.1 of the cams 40 therefore do not define a circle with mirror images thereof. Each cam 40 is mounted to its associated jaw 12A, 12B in a semicircular semi-annular cam cavity or slot 21 , forming part of the semi-circular cavity 20. The slots 21 are defined operatively behind the crimping elements 36 in their associated jaws 12A, 12B, being at least partly defined by the spacing formations 38 such that the crimping element passages 36 extend radially outwardly, i.e. operatively rearwardly, into the slots 21 of their associated jaws 12A, 12B. The slots 21 of the respective jaws 12A, 12B together define an annular slot having its midpoint at the crimping axis "A" when the jaws 12A, 12B are in abutment along the facing side faces 16A.1 , 16B.1 thereof. The cams 40 are mounted in their associated jaws 12A, 12B such that the manipulating members 40.2 of the cams 40 project through the slots 26 of their associated jaws 12A, 12B when the cams 40 are received in their respective slots 21 .

The slots 21 are curved complementally to the bodies 40.1 of the cams 40, each slot defining a semi-circular cam displacement path along which the body 40.1 of its associated cam 40 is angularly slidably displaceable about the crimping axis "A", so as to move or slide the cam surface 40.3 of the cam 40 across the longitudinal axes "B" of the crimping elements 36 of its associated jaw 12A, 12B and thus also across the radii on which the crimping elements 36 are disposed. It will be appreciated that, as the slots 21 , and thus the respective displacement paths defined thereby, are semi-circular in profile, in contrast to the operatively inner and outer surfaces 40.3, 40.4 of the bodies 40.1 of the cams 40 which have part-circular profiles of lesser magnitude than a semi-circle of a circle of which their part-circular profiles form part, the bodies 40.1 of the cams 40 are rendered displaceable in their associated slots 21 about the crimping axis "A". More particularly, in comparison to the part-circular profiles of the cam bodies 40.1 , it will be appreciated that an included angle between radii of a circle of which the semi-circular slots 21 form part is 180 ° .

An extent to, or rather a displacement angle "D" (see Figures 4 and 6) through which the cams 40 are displaceable about the crimping axis "A" along the displacement paths in their associated slots 21 , is limited by abutment of their associated manipulating members 40.3 against the sidewalls 26.1 of the passages 26. Desirably, the passages 26 each has a sufficient spacing between its sidewalls 26.1 for each manipulating member 40.3 to displace its associated cam body 40.1 angularly through the displacement angle "D" (see Figures 4, 6 and 7) about the crimping axis "A" along the whole of the semi-circular displacement path defined by its associated slot 21 , i.e. from a position wherein one end face 40.1 A thereof is flush with the side face 16.1 A/16.1 B of its associated jaw 12A/12B at one end of the slot 21 (see Figures 3 and 4), to a position wherein another end face 40.1 B thereof is flush with said side face 16.1 A/16.1 B at the other end of the slot 21 (see Figures 6 and 7). In the illustrated embodiment, said displacement angle "D" is 18 ° . It will be appreciated that, depending on the arcuate length of the bodies 40.1 of the cams 40, as well as on the angular spacing of the crimping elements 36 relative to each other and, in particular, the desired location of the crimping faces 36.2 when in the extended and retracted configurations respectively, the displacement angle may be larger or smaller than 18 ° .

The crimping elements 36 are connected to the cams 40 of their associated jaws 12A, 12B along the cam surfaces 40.3 thereof by means of respective connecting elements which are in the form of pawls 42. As is more clearly illustrated in Figure 2c, each pawl 42 has opposite front and rear end portions 42.1 , 42.2 which are connected by an elongate middle portion 42.3. The front and rear end portions 42.1 , 42.2 of the pawls 42 are part-circular in plan view outline with the rear portion 42.2 having a greater diameter than the front portion 42.1 . The pawls 42 are pivotally connected both to their associated cams 40 and to their associated crimping elements 36 at respective connection points defined respectively on the cams 40 and on the crimping elements 36. Both the cam and crimping element connection points are defined by respective cam and crimping element connections comprising cam and crimping element recesses or slots 46, 48.

The cam slots 46 are defined in the cam surface 40.3 equidistally from each other at equiangularly spaced positions about the crimping axis "A", equal to the angular spacings of the crimping elements 36, i.e. 60 ° relative to each other about the crimping axis "A". It will be appreciated that the cam slots 46 can thus all be brought into radial register with their associated crimping elements 36 simultaneously by displacement of their associated cams 40 along their respective displacement paths about the crimping axis "A".

The crimping element slots 48 are defined in rear portions 36.6 of the crimping elements. The slots 46, 48 have plan view outlines which are complemental to the cross sectional outlines respectively of the rear and front end portions 42.2, 42.1 of the connecting elements so as to define respective pivot axes with these portions 42.2, 42.1 respectively and to receive said portions of the connecting elements 42.2, 42.1 pivotally therein. Each pawl 42 has a longitudinal axis Έ" defined from its associated cam connection point to its associated crimping element connection point, thus connecting midpoints of the respective slots 46, 48 and of the respective front and rear portions 42.1 , 42.2 of the pawls 42 (see Figures 3, 5 and 6.

As also indicated hereinbefore, the displacement paths of the cams 40, defined by the slots 21 , allow for angular displacement of the cams 40 selectively through the cam displacement angle "D". Such displacement serves to bring the connections of the respective pawls 42, i.e. the slots 46, 48 associated with the respective pawls 42, into a configuration of simultaneous radial register or alignment with each other (as illustrated in Figure 5) from an initial configuration of non-radial register or alignment (as illustrated in Figures 3, 4, 6 and 7) along the displacement path. It will be appreciated that, by such angular displacement, the pawls 42 are pivoted and are thus also angularly displaced along with their longitudinal axes Έ", with the axes Έ" thereby being moved from a configuration of non-alignment with the longitudinal axes "B" (see again Figures 3, 4, 6 and 7) of their associated crimping elements 36 into a configuration of alignment with said longitudinal axes "B" (see again Figure 5). As the outer ends 42.2 of the pawls 42 are fixed for pivotal movement with their associated cams 40, these end portions 42.2 remain at a fixed radial spacing from the crimping axis "A". The inner ends 42.1 of the connecting elements 42, on the other hand, being connected to respective crimping elements 36, are not capable of angular displacement along with the cam 40. Thus, the angular displacement of the connecting elements 42 cause the inner ends 42.1 of the connecting elements 42 to move deeper into the passages 35 of their associated crimping elements 36, thereby causing the crimping elements 36 to be synchronously radially inwardly displaced into their extended configurations.

More particularly, when the crimping elements 36 are in the retracted configuration, the manipulating elements 40.2 of the cams 40 are in abutment with one of the sidewalls 26.1 of their associated passages 26. In this configuration, the cams 40 are disposed in their associated slots 20.1 such that the ends 40.1 A of the respective cams 40 are substantially flush with the facing side faces 16.1 A, 16.1 B of their associated jaws 12A, 12B. In this configuration, the pawls 42 are oriented obliquely in plan view relative to their associated crimping elements 36, longitudinal axes Έ" of the pawls 42 being offset from the longitudinal axes "B" of their associated crimping element 36 at a crimping angle "F", which is 9 ° in the illustrated embodiment, i.e. half of the displacement angle "D". It will be appreciated that angular displacement of the cams 40 along their angular displacement paths about the crimping axis "A" causes the ends 42.1 , 42.2 of the pawls 42 to pivot in their associated slots 46, 48 whilst also being angularly displaced equally to the angular displacement of their associated cams 40. Thus, by displacing the cam 40 half-way along its angular displacement path about the crimping axis "A", i.e. an angular displacement of 9 ° , the pawls 42 are also angularly displaced through 9 ° and the crimping angle "F" is closed such that the longitudinal axes "B" and Έ" are brought into alignment or register with each other. The angular displacement of the pawls 42 extends the front ends 42.1 of the pawls 42 further into the passages 35 of their associated crimping elements 36, thereby simultaneously and synchronously displacing the crimping elements 36 radially inwardly. The crimping elements 36 thus synchronously converge towards the crimping axis "A" to abut each other along adjacent abutment faces 36.4 thereof to form the segmented crimping faces and, together when the jaws 12A, 12B are in abutment with each other along the facing side faces 16A.1 , 16B.1 thereof, form the segmented crimping ring 17. Lengths of the crimping elements 36 as well as angles of taper of the abutment faces 36.6 are chosen such that the radial displacement of the crimping elements 36 due to the angular displacement of the pawls 42 is sufficient to bring the abutment faces of the crimping elements into abutment with each other synchronously and simultaneously when the crimping angle "F" has been closed and the longitudinal axes "B", Έ" are in alignment, as is illustrated in Figure 5.

However, as indicated hereinbefore, the angular displacement paths, or displacement angles "D" of the cams 40 each extend 18 ° about the crimping axis "A". Therefore, by continuing displacement of the cams 40 along their angular displacement paths through a further, or rather the remaining, 9 ° the pawls 42 are progressively withdrawn from the passages 35 of their associated crimping elements 36, thereby displacing the crimping elements 36 operatively outwardly or rearwardly and consequently moving the front end faces 34.2 thereof into the retracted configuration, as is illustrated in Figures 6 and 7.

In use in crimping the mouth of the detonator housing 34 around an initiating element protruding into the housing through the mouth, the device 10 will initially, i.e. at commencement of a crimping sequence, as described below, for crimping the detonator housing 34, be in an initialization configuration, in which it is illustrated in Figures 1 and 3, with the jaws 12A, 12B being spaced apart a spacing "S" from each other and with the detonator housing 34 being positioned through the action of the conveyor system as hereinbefore described in between the jaws 12A, 12B in a position where it is concentric with the hypothetical crimping axis "Α- '. In crimping the detonator housing 34, the device 10 is manipulated or controlled through the following crimping sequence which includes, preferably but not necessarily in the specific order described,

(i) bringing the jaws 12A, 12B tightly in abutment with each other along the facing side faces 16A.1 , 16B.1 thereof such that the detonator housing 34 is secured in the cutout ring defined by the part-circular cutouts 30, as is illustrated in Figure 4;

(ii) displacing the cams 40 angularly along their respective displacement paths through the crimping angle "F", i.e. halfway through their displacement angles "D", such that the connecting elements 42 move or extend their associated crimping elements 36 radially inwardly such that the front end faces 36.2 thereof are in the extended configuration with the abutment faces 36.4 of adjacent elements 36 in the same jaw 12A, 12B and adjacent elements in different jaws 12A, 12B being in abutment and with the front end faces 36.2 of the crimping elements 36 collectively defining the crimping ring 17 which engages the mouth of the detonator housing 34 and crimps the mouth of the detonator housing, as is illustrated in Figure 5;

(iii) continuing displacement of the cams along their respective displacement paths such that the connecting elements move or retract their associated crimping elements 36 radially inwardly, thereby displacing the front end faces 36.2 thereof towards the retracted configuration, the front end faces 36.2 thereby disengaging the crimped detonator housing 37, as is illustrated in Figure 6; (iv) spacing the jaws 12A, 12B from each other such that the crimped detonator housing can be removed from between the jaws 12A, 12B; and

(v) returning the device 10 to its initialization configuration, by returning the cams 40 along their respective displacement paths, as is illustrated in Figure 3.

Referring now to Figures 8 through 10, reference numeral 200 generally indicates another embodiment of a crimping device in accordance with the invention. In Figures 8 through 10, the same reference numerals used in Figures 1 through 7 are used to designate parts of the device 200 which correspond to parts of the device 10.

The device 200, in crimping a detonator housing, operates similarly to the device 10, i.e. through cam-driven radial displacement of radially arranged crimping elements 36.

In contrast to the device 10, the support 1 1 of the device 200 does not comprise the two oppositely mounted jaws 12A, 12B of the device 10, but instead comprises a unitary support block or member 202. A detonator housing receiving throughbore 201 is defined centrally in the support block 202 and constitutes a detonator receiving ring, similarly to the cutouts of the jaws 12A, 12B of the device 10 together. The throughbore 201 is coaxial with the crimping axis TV. The crimping elements 36 are disposed in the support block 202 relative to each other in identical fashion to the fashion in which the crimping elements 36 are disposed relative to each other in the device 10, when the device 10 is in the detonator housing securing, detonator housing crimping and detonator housing disengaging configurations, as illustrated in Figures 4 through 6 respectively. Thus, more specifically, the crimping elements 36 are arranged on respective equiangularly spaced radii 'B' of the crimping axis TV. As with the device 10, the radial spacing 'C between adjacent elements is 60°. As the support 202 is in the form of a unitary block as opposed to comprising the two jaws 12A, 12B, the crimping elements 36 are mounted in the support block 202 in a single crimping element cavity of circular cross section, generally designated by reference numeral 203, as opposed to being arranged in the semi-circular cavities 20, as is the case in the device 10.

Further, the device 200 does not comprise two cams 40 as in the case of the device 10, but has only one cam 204. The cam 204 has an annular body 204.1 of circular plan view outline, an inner face thereof defining a circular cam surface 206 which is co-axial with the crimping axis "A" and which surrounds the crimping elements 36. The cam also has a control member 204.2 which projects radially from the cam body 204.1 beyond outer extremities of the support block 202 through a slot 207 defined in the block 202. The cam 204 is mounted in an annular cam cavity 205 which is surrounds the crimping elements 36 in the support block 202 and into which the crimping element passages 35 extend so as to allow communication between the crimping elements 36 and the cam surface 206. Connection of the crimping elements 36 to the cam 204 and displacement of the crimping elements 36 by means of the cam occurs in similar fashion to that of the device 10, as the device 10 is displaced through the detonator housing securing, detonator housing crimping and detonator housing disengaging configurations. Of course, in the device 200, all of the crimping elements 36 are associated with and operatively connected to the cam 204, as opposed to the device 10 in which the crimping elements 36 associated with each of the respective jaws 12A, 12B are connected to their respective associated cams 40.

The cam 204 only has one controlling member 204.1 by which displacement of the cam 204 and corresponding displacement of the crimping elements 36 are effected. The crimping elements 36 of the device 200 are connected to the cam

204 along the cam surface 206 thereof by means of pawls 42 in similar fashion as in the case of the device 10.

Thus, in use, the device 200 is employed in crimping a detonator housing in the following sequence, as illustrated in Figures 8 through 10:

(i) with the device 200 in a detonator housing receiving condition with the crimping elements 36 in their retracted configurations, as is illustrated in Figure 8, a detonator housing is inserted into the receiving ring either from above or from below the support block 202, in axial alignment with the crimping axis "A"; (ii) the cam 204 is then displaced partly through the displacement angle Ό', more particularly through the crimping angle "F", thereby also to effect displacement of the pawls 42 through the crimping angle 'F' and thereby displace their associated crimping elements 36 into their extended configuration such that front faces of the crimping elements 36 together define the crimping ring 17 and act to exert a radial force on the detonator housing and radially crimp the detonator housing;

(iii) displacement of the cam 204 is continued through the whole of the displacement angle "D", with the crimping elements 36 being displaced or retracted by their associated pawls 42 back into the retracted configuration, thereby disengaging the crimped detonator housing and allowing the housing to be removed from the receiving passage and another housing to be inserted into the receiving ring to be crimped. The Applicant has found that the device according to the invention, as hereinbefore described, effects uniform and substantially circular radial crimping of the mouth of a detonator housing about a circumference of the housing, as is illustrated by Figure 1 1 . This is in contrast to prior art devices, such as that of WO2008/056333, the crimping effect of which is illustrated by Figure 12.

The Applicant has further found, in conducting experimental quality tests on detonators comprising detonator housings crimped by means of the crimper of the present invention with shock tubes intruding into the housing, that these detonators have acceptable resistance to pull-out of the shock tube in relation to prior art devices. More particularly, the Applicant conducted a series of pull-out trials on detonators comprising detonator housings crimped by the crimper of the present invention. The results of these trials are presented in Tables 1 and 2 below.

The trials were conducted for two desired crimping diameters, in particular 5.6mm and 6mm. A crimping device in accordance with the present invention was set up for each of these diameters and was employed in crimping a detonator housing about a shock tube intruding into the housing.

Subsequent to crimping, the minimum and maximum diameters of the crimp were measured and the ovality of the crimp determined by calculating the average of the maximum and minimum diameters. A pull-out test was then conducted on the shock tube whilst mounted to the housing to determine the holding quality of the crimp:

Table 1 : Results of 6mm crimp trial runs

Crimp Diameter (mm) Shock tube Diameter (mm) Pullout

Test failure

Trial run Min Max Ovality Min Max Ovality load (N)

1 6.09 6.28 6.1 9 2.91 2.98 2.95 79.06

2 6.07 6.44 6.26 2.89 2.96 2.93 1 01 .32

3 6.09 6.35 6.22 2.94 3.00 2.97 1 00.36

4 6.10 6.38 6.24 2.86 2.97 2.92 85.52

5 6.09 6.42 6.26 2.87 2.91 2.89 88.06 6 6.1 1 6.30 6.21 2.90 2.96 2.93 90.37

7 6.1 1 6.32 6.22 2.91 2.99 2.95 95.41

8 6.15 6.38 6.27 2.93 2.96 2.95 99.94

9 6.1 1 6.35 6.23 2.87 2.96 2.92 94.1 9

1 0 6.13 6.38 6.26 2.98 3.03 3.01 87.88

1 1 6.17 6.25 6.21 2.91 3.04 2.98 97.28

12 6.12 6.32 6.22 2.99 3.08 3.04 1 01 .72

13 6.17 6.38 6.28 2.92 3.00 2.96 87.93

14 6.13 6.49 6.31 3.04 3.09 3.07 1 00.61

1 5 6.21 6.47 6.34 2.87 2.93 2.90 80.81

1 6 6.08 6.35 6.22 2.96 3.04 3.00 90.30

1 7 6.13 6.37 6.25 2.83 2.97 2.90 90.32

1 8 6.12 6.31 6.22 2.92 3.00 2.96 89.64

1 9 6.15 6.38 6.27 3.06 3.07 3.07 99.92

20 6.1 1 6.32 6.22 2.92 2.96 2.94 94.83

21 6.1 1 6.36 6.24 2.92 3.00 2.96 99.91

22 6.1 1 6.36 6.24 2.89 2.94 2.92 95.91

23 6.12 6.39 6.26 2.96 3.05 3.01 94.32

24 6.1 1 6.32 6.22 2.96 3.01 2.99 96.13

25 6.07 6.39 6.23 2.93 2.96 2.95 86.40

26 6.15 6.34 6.25 2.85 3.02 2.94 88.73

27 6.1 1 6.30 6.21 2.84 2.97 2.91 72.1 0

28 6.10 6.35 6.23 2.81 2.96 2.89 82.81

Avg 6.12 6.36 6.24 2.91 2.99 2.95 91.85

Min 6.07 6.25 6.19 2.81 2.91 2.89 72.10

Max 6.21 6.55 6.37 3.06 3.09 3.07 101.72

Stdev 0.032476 0.063698 0.039645 0.057385 0.048812 0.049112 7.511163

Table 3: Results of 5.6mm trial runs Crimp Diameter (mm) Shock tube Diameter (mm) Pullout

Test failure

Trial run Min Max Ovality Min Max Ovality load (N)

1 5.98 6.08 6.03 2.80 3.1 1 2.96 107.22

2 5.91 6.05 5.98 2.88 2.91 2.90 97.22

3 5.89 6.12 6.01 2.85 2.99 2.92 91 .14

4 5.86 6.15 6.01 2.94 3.01 2.98 95.48

5 5.96 6.15 6.06 2.91 3.03 2.97 102.78

6 5.96 6.13 6.05 2.89 3.04 2.97 97.61

7 5.84 6.10 5.97 2.82 3.02 2.92 95.63

8 5.93 6.1 1 6.02 2.84 3.1 1 2.98 101 .09

9 5.96 6.15 6.06 2.98 3.04 3.01 99.20

10 5.89 6.15 6.02 2.91 3.02 2.97 94.61

11 5.92 6.22 6.07 2.80 2.98 2.89 99.22

12 5.98 6.18 6.08 2.97 3.01 2.99 96.72

13 5.98 6.09 6.04 2.83 2.90 2.87 93.33

14 5.88 6.12 6.00 2.91 2.96 2.94 88.1 1

15 5.98 6.18 6.08 2.94 3.05 3.00 101 .03

16 5.99 6.1 1 6.05 2.95 3.05 3.00 96.90

17 5.95 6.14 6.05 2.96 3.04 3.00 103.15

18 5.97 6.12 6.05 2.88 3.08 2.98 99.32

19 5.94 6.12 6.03 2.90 3.01 2.96 99.29

20 5.90 6.10 6.00 2.89 3.08 2.99 96.70

21 5.90 6.08 5.99 2.86 3.02 2.94 93.58 22 5.94 6.1 1 6.03 2.90 2.99 2.95 97.70

23 5.95 6.15 6.05 2.89 3.00 2.95 1 00.37

24 5.90 6.18 6.04 2.87 3.04 2.96 1 05.72

25 5.95 6.15 6.05 2.91 3.00 2.96 1 02.63

26 5.95 6.12 6.04 2.95 3.00 2.98 96.79

27 5.93 6.1 1 6.02 2.94 3.03 2.99 1 01 .43

28 5.89 6.15 6.02 2.92 3.00 2.96 92.93

29 5.92 6.14 6.03 2.91 3.02 2.97 95.74

30 5.92 6.15 6.04 2.93 3.01 2.97 93.66

Avg 5.93 6.13 6.03 2.90 3.02 2.96 97.88

Min 5.84 6.05 5.97 2.80 2.90 2.87 88.11

Max 5.99 6.22 6.08 2.98 3.11 3.01 107.22

Stdev 0.038679 0.035183 0.026953 0.048187 0.046393 0.033851 4.249063

The failure load results of the pull-out trials are represented graphically in Figure 13.

In the Applicant's experience, it is desirous to effect a crimp having a pull-out failure load greater than 80 Newton. As can be seen from the results of the 28 trial runs conducted in respect of the 6mm crimp and the 30 trial runs conducted in respect of the 5.7mm crimp, the detonators exhibited excellent shock tube retention capability, particularly for the 5.7mm crimp.

The Applicant further conducted a series of so-called "pressure-pot" tests on detonators manufactured by means of the crimper of the present invention. These tests involve immersing the detonators in water in a pressurized vessel to assess their resistance to ingress of water. The detonators were subjected to a continuous pressure-pot test over a period of 50 hours and exhibited excellent water resistant behaviour, with virtually no ingress of water into the detonator housing being detected. As will be appreciated, the ingress of water into a detonator, which generally comprises a series arrangement of explosives, may impact negatively on the performance of the detonator, resulting in misfiring or delayed firing, which is highly undesired.

The crimper of the present invention therefore effects uniform and substantially circular radial crimping of the mouth of a detonator housing about a circumference of the housing.