Primer

• US 5,069,131 A
• Filed: 09/25/1989
• Issued: 12/03/1991
• Est. Priority Date: 09/23/1988
• Status: Expired due to Fees

• Current Assignee: Orica Explosives Technology Pty Limited (Orica Limited)
• Original Assignee: ICI Australia Operations Proprietary Limited
• Inventors: Kennedy, David, Smetham, James N., Mussett, Gerard, Van Maanan, Alfons
• Primary Examiner(s): Kyle, Deborah L.
• Assistant Examiner(s): Johnson, Stephen
• Application Number:
  US07/412,202
• Time in Patent Office: 799 Days
• Field of Search: 102/275.1, 102/275.2, 102/275.4, 102/275.5, 102/275.6, 102/275.7, 102/202.14
• US Class Current: 102/275.6
• CPC Class Codes: F42B 3/00 Blasting cartridges, i.e. case and explosive fuse cords, e.g. detonating fuse cords C06C5/00; chemical aspects of detonators, blasting caps or primers C06C7/00
• CPC Class Codes: F42B 3/26 Arrangements for mounting initiators; Accessories therefor, e.g. tools

Abstract

A primer is provided for use in detonating an explosive charge. The primer includes a rigid explosive-filled container which is fitted with an elongated neck. A bore in the neck extends into the explosive of the primer and provides accommodation for a firing device such as a detonator or fusecord. The primer is attached to a shock tube/wiring of a detonator or a fusecord with a fastener which is located at the end of the neck remote from the container and which is capable of supporting the entire weight of the primer. The container is preferably spherical and the neck is preferably formed from a plastics material which is molded with protrusions around which the fusecord/shock tube/wiring can be looped and with a griping device to hold them in place. The primers of the invention are particularly safe and efficacious in use.

Claims

1. A primer for detonating explosives, the primer being fired by firing means which receives a firing signal via continuous elongate flexible transmission means directly connected to the firing means, the primer comprising a charge of explosive to which charge is appended an elongate neck, there being within the neck and the charge a continuous bore having an axis substantially parallel to a longitudinal axis of the neck and dimensioned so as to accommodate said firing means to an extent which ensures at least one of protection of said firing means and an efficient functioning of said firing means, the neck comprising, at an end thereof remote from the primer charge, fastening means for fastening the primer to the transmission means such that the primer can be fully supported by said transmission means and wherein there is within the primer explosive charge a hollow insert having a bore of a diameter which permits a firm fitting of the firing means.

2. A primer according to claim 1, wherein the continuous bore is substantially coaxial with the neck.

3. A primer according to claim 1, wherein the charge of explosive is housed within a rigid container to which the neck is attached.

4. A primer according to any one of claims 1--3, wherein the primer is one of cylindrical, and spherical.

5. A primer according to claim 4, wherein the primer is spherical.

6. A primer according to claim 1, wherein the firing means is a detonator and the hollow insert is so dimensioned that a base charge of the detonator is located substantially adjacent a geometric centre of the primer explosive charge.

7. A primer for detonating explosives, the primer being fixed by firing means which receives a firing signal via continuous elongate flexible transmission means directly connected to the firing means, the primer comprising a charge of explosive to which charge is appended an elongate neck, there being within the neck and the charge a continuous bore having an axis substantially parallel to a longitudinal axis of the neck and dimensioned so as to accommodate said firing means to an extent which ensures at least one of protection of said firing means and an efficient functioning of said firing means, the neck comprising, at an end thereof remote from the primer charge, fastening means for fastening the primer to the transmission means such that the primer can be fully supported by said transmission means and wherein the fastening means comprises gripping means for gripping the transmission means and attaching means for attaching the gripping means to a remainder of the neck, the gripping means comprising:

(i) a pair of opposed jaws at least one of which jaws is movable towards the other, which jaws comprise gripping surfaces which are so shaped as to deform the transmission means in a plane of closing motion of the jaws such that the transmission means may be gripped to a desired extent; and

(ii) securing means for holding the jaws in fastening contact with the transmission means.

8. A primer for detonating explosives, the primer being fired by firing means which receives a firing signal via continuous elongate flexible transmission means directly connected to the firing means, the primer comprising a charge of explosive to which charge is appended an elongate neck, there being within the neck and the charge a continuous bore having an axis substantially parallel to a longitudinal axis of the neck and dimensioned so as to accommodate said firing means to an extent which ensures at least one of protection of said firing means and an efficient functioning of said firing means, the neck comprising, at an end thereof remote from the primer charge, fastening means for fastening the primer to the transmission means such that the primer can be fully supported by said transmission means, and wherein the fastening means is so shaped externally as to define a pathway which the transmission means is constrained to follow such that, in following the pathway of said transmission means from which the primer is suspended, a transmission means loop in a substantially vertical plans, the pathway being additionally equipped with at least one gripping member at least one of which is positioned at a part of the loop wherein, when the primer is suspended from that part of the loop of the transmission means, a tangent drawn to that part of the loop is substantially horizontal.