Abstract: For use in a system having a master device and slave devices (e.g., an electronic blasting system) and utilizing an automatic detection process that causes any slave devices that have not previously been identified to the master device to identify themselves to the master device, an enhancement to the detection process employs at least a second discriminator to detect superimposed responses from simultaneously responding slave devices, and a “deconvolution” algorithm in order to ascertain their identities.

Abstract: A method for logging a plurality of slave devices is suggested, comprising the following steps: a) connecting a plurality of slave devices each having an identity and a pyrotechnic charge to an electrical conduit; b) after step a), connecting a logging device comprising a power supply, an electrical interface, and a memory and c)causing the logging device to communicate with each of the plurality of slave devices while the plurality of slave devices is simultaneously connected to the electrical conduit.

Abstract: A method of axially spinning an initiator subassembly after the loading of a pyrotechnic charge therein, in order to distribute the charge.

Abstract: A pair of explosive detonators are recessed in the end of a cylindrical body containing a permanent magnet, which serves as the rotor in a brushless, bi-directional torque motor enclosed in a housing. A reversible positioning current causes the motor to rotate the body between armed and safe positions and thereby establish and interrupt axial explosive transfer paths from the detonators to a corresponding pair of explosive transfer lines ported through the housing cover. An internal switching circuit disables the detonators when the body is in the safe position and passes a firing current to them when the body is in the armed position. A detent ring secured to the rotatable body, and a pair of spring-loaded detents in the housing index the rotatable body in the armed and safe positions and prevent its accidental rotation. Mechanical safing means are provided for manually overriding an electrical arming signal.

Abstract: An electro-explosive initiator which may be either a coaxial or floating case type, for example, and which is constructed to be immune from the effects of electrostatic discharges. The initiator includes a bridgewire and contact pins for carrying an electric igniting signal to the bridgewire. The initiator has a discrete capacitor connected across the contact pins to shunt out the energy resulting from an electrostatic discharge pulse, and for preventing such energy from reaching the bridgewire.

Abstract: A medical instrument for measuring depth of fastener hole in bone. The depth gauge has a scale tube which fits into fastener hole in bone. The zero index of scale tube expands exclusively in radial dimension to a diameter greater than the hole diameter, affording a positive stop for the zero index, thus insuring precise alignment of scale zero index with edge of hole in distal bone wall. A sliding scale marker is frictionally mounted to scale tube, affording a record of the measurement.