U.S. patent application number 10/691751 was filed with the patent office on 2005-06-02 for safe electronic pyro trigger.
This patent application is currently assigned to Honeywell International Inc.. Invention is credited to DeBona, Michael T., Webb, Winston S..
Application Number | 20050115433 10/691751 |
Document ID | / |
Family ID | 34619766 |
Filed Date | 2005-06-02 |
United States Patent
Application |
20050115433 |
Kind Code |
A1 |
Webb, Winston S. ; et
al. |
June 2, 2005 |
Safe electronic pyro trigger
Abstract
An electronic trigger for pyro testing has a mechanical relay
that is normally open. The relay is fired by electronic logic that
times out two seconds after attempting to close the relay to
trigger a device, such as a device coupled to explosive material.
This results in the relay returning to its normally open state. By
virtue of the mechanical relay being in a normally open state, no
current may pass through the relay after the logic times out. A
display shows status of the trigger and a count down following user
activation of an enable arm switch. The countdown is stopped upon
activation of the abort switch, also preventing activation of the
mechanical relay.
Inventors: |
Webb, Winston S.; (Largo,
FL) ; DeBona, Michael T.; (Pinellas Park,
FL) |
Correspondence
Address: |
SCHWEGMAN, LUNDBERG, WOESSNER & KLUTH, P.A.
P.O. BOX 2938
MINNEAPOLIS
MN
55402
US
|
Assignee: |
Honeywell International
Inc.
|
Family ID: |
34619766 |
Appl. No.: |
10/691751 |
Filed: |
October 22, 2003 |
Current U.S.
Class: |
102/200 |
Current CPC
Class: |
F42C 21/00 20130101;
F42D 1/05 20130101 |
Class at
Publication: |
102/200 |
International
Class: |
F42C 001/00 |
Claims
1. An electronic trigger comprising: a first relay having a trigger
output; a second relay coupled to the first relay that selectively
enables the first relay; and a controller coupled to the first
relay and to the second relay, wherein the controller provides an
enable signal to the second relay to enable the first relay, and
provides a signal to the first relay for providing the trigger
output when the first relay is enabled.
2. The electronic trigger of claim 1 wherein the first relay
comprises a normally open mechanical switch.
3. The electronic trigger of claim 1 wherein the controller is
coupled to user inputs.
4. The electronic trigger of claim 3 wherein the user inputs
comprise an enable arm switch, an enable count switch and an abort
switch.
5. The electronic trigger of claim 4 wherein the enable arm switch
causes the controller to enter a safe mode loop.
6. The electronic trigger of claim 5 wherein the enable count
switch causes the controller to count down from a predetermined
number.
7. The electronic trigger of claim 1 and further comprising a
display coupled to the controller.
8. The electronic trigger of claim 1 and further comprising a
current driver coupled between the controller and the second relay
for providing a current to enable the first relay.
9. The electronic trigger of claim 1 and further comprising a third
relay coupled between the controller and the first relay for
switching current to the first relay under control of the
controller, wherein the current becomes the output signal of the
first relay.
10. An electronic trigger comprising: a blast relay having an
output for triggering a blast cap; means for activating the blast
relay; and means for providing a signal to the blast relay for
providing the output for triggering the blast cap.
11. The electronic trigger of claim 10 and further comprising means
for displaying the status of the controller.
12. An electronic trigger comprising: a set of user inputs
comprising an enable arm switch, an enable count switch and an
abort switch; a first relay having an output for triggering a blast
cap, wherein the first relay has a switch and a field generator; a
second relay coupled to the first relay for enabling the field
generator to activate the first relay switch; a third relay coupled
to the first relay for providing a signal that is passed through
the first relay switch as the output signal when the first relay
switch is activated; a display; and a controller that receives the
user inputs, provides status and countdown signals to the display,
and controls the second and third relays.
13. A method for controlling an output signal provided to a device,
the method comprising: enabling a relay; providing a signal to the
relay that is provided as the output signal when the relay is
enabled; disabling the relay after a predetermined time; and
removing the signal to the relay.
14. The method of claim 13 wherein the relay is disabled prior to
stopping providing the signal to the relay.
15. The method of claim 13 wherein the predetermined time is
approximately three seconds.
16. The method of claim 13 and further comprising counting down by
seconds from a predetermined number of seconds prior to enabling
the relay.
17. An electronically implemented method for controlling an output
signal provided to a device, the method comprising: entering a safe
mode loop; entering an enable loop; entering a countdown loop;
enabling a relay after a predetermined time in the countdown loop;
providing a signal to the relay that is provided as the output
signal when the relay is enabled; disabling the relay after a
predetermined amount of time; and removing the signal to the
relay.
18. The method of claim 17 and further comprising providing status
signals to a display.
19. The method of claim 17 wherein the enable loop is entered after
detecting actuation of an enable arm switch.
20. The method of claim 19 wherein the count down loop is entered
following the enable loop, and in response to detection of
actuation of an enable count switch.
21. The method of claim 19 wherein the relay is disabled and the
signal to the relay is stopped upon detection of actuation of an
abort switch.
22. The method of claim 16 and further comprising firing a blasting
while the relay is enabled and the signal is provided to the
relay.
23. A system for controlling an output signal provided to an
explosive device, the method comprising: means for enabling a
relay; means for providing a signal to the relay that is provided
as the output signal when the relay is enabled; means for disabling
the relay after a predetermined time; and means for removing the
signal to the relay.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to electronic pyro triggers,
and in particular, to a failsafe electronic pyro trigger.
BACKGROUND OF THE INVENTION
[0002] Explosive devices including blast caps are routinely pyro
tested in blast cells by test engineers or technicians. When pyro
testing, people need a fail safe electronic trigger to protect them
while working in a blast cell. When a faulty blast cap is
encountered during testing, it is crucial to know that a blasting
trigger will not try to fire the cap after a count down is over, or
halted by an abort command.
SUMMARY OF THE INVENTION
[0003] An electronic trigger for pyro testing has a mechanical
relay that is normally open. The relay is fired by electronic logic
that times out two seconds after attempting to close the relay to
trigger a device, such as a device coupled to explosive material.
This results in the relay returning to its normally open state. By
virtue of the mechanical relay being in a normally open state, no
current may pass through the relay after the logic times out.
[0004] In one embodiment, the electronic logic is a microprocessor.
The microprocessor has an enable arm switch and an abort switch as
inputs. The microprocessor operates software that drives a solid
state relay linked to a mechanical relay that fires a blasting cap
device. Another output drives a transistor that controls a field
that drives the mechanical relay. A four bit output drives a
display for showing a count down following user activation of the
enable arm switch. The countdown is stopped upon activation of the
abort switch, also preventing activation of the solid state relay
and the field in the mechanical relay.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] FIG. 1 is a block diagram of a fail safe electronic pyro
trigger according to an embodiment of the invention.
[0006] FIG. 2 is a more detailed block diagram of the fail safe
electronic pyro trigger according to an embodiment of the
invention.
[0007] FIG. 3 is a block diagram of top view of a fire box
incorporating the fail safe electronic pyro trigger according to an
embodiment of the invention.
[0008] FIG. 4 is a flow chart of functions performed by the fail
safe electronic pyro trigger according to an embodiment of the
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0009] In the following description, reference is made to the
accompanying drawings that form a part hereof, and in which is
shown by way of illustration specific embodiments in which the
invention may be practiced. These embodiments are described in
sufficient detail to enable those skilled in the art to practice
the invention, and it is to be understood that other embodiments
may be utilized and that structural, logical and electrical changes
may be made without departing from the scope of the present
invention. The following description is, therefore, not to be taken
in a limited sense, and the scope of the present invention is
defined by the appended claims.
[0010] The functions or algorithms described herein are implemented
in software or a combination of software and human implemented
procedures in one embodiment. The software comprises computer
executable instructions stored on computer readable media such as
memory or other type of storage devices. The term "computer
readable media" is also used to represent carrier waves on which
the software is transmitted. Further, such functions correspond to
modules, which are software, hardware, firmware or any combination
thereof. Multiple functions are performed in one or more modules as
desired, and the embodiments described are merely examples. The
software is executed on a digital signal processor, ASIC,
microprocessor, or other type of processor operating on a computer
system, such as a personal computer, server or other computer
system.
[0011] A fail safe electronic trigger system is shown generally at
100 in FIG. 1. In one embodiment, system 100 has a user input 110
having a first enable switch 112, a second enable switch 114 and an
abort switch 116 coupled to a controller 120. The controller may be
a microprocessor or any other type of device capable of executing
logic to provide one or more output signals in response to multiple
inputs. In one embodiment, the outputs are used to provide a status
of the controller, including a visible countdown on a display 125
for activation of a blasting cap represented as output 130. An
output 132 to display 125 is a four bit output in one embodiment to
drive a single character 7 segment light emitting diode (LED)
display. Many other types of outputs and displays may be used.
[0012] First enable switch 112 is an enable arm switch that is used
to initialize or arm the controller 120, and the second enable
switch 114 is an enable count switch that is used to start a
countdown by the controller 120. Numerous other types of switches
may also be used.
[0013] The controller also drives a relay 135 that is linked to a
mechanical blasting relay 140 that fires the blasting cap at 130.
Relay 135 is a solid state relay in one embodiment. Blasting relay
140 is normally open. Another output is coupled to a current
amplifier 142 that drives a relay 145 that controls a field that
drives the blasting relay 140. Output 132 drives the display 125
for showing a count down following user activation of the enable
count switch 114. The countdown is stopped upon activation of the
abort switch 116, also preventing activation of the solid state 135
and blasting 140 relays. A predetermined time after the countdown
ends, activation of the solid state 135 and blasting 140 relays is
also prevented.
[0014] Further detail of the system 100 is shown in FIG. 2. Display
125 contains both an LED character 210 and a fire lock out lamp
215, which is on when the blasting relay 140 is prevented from
firing the blasting cap. Solid state relay 135 contains an element
or circuitry logically represented as a coil 220 coupled to the
controller 120, and a switch 225 activated by the circuitry 220.
Switch 225 is coupled to a switch 230 in blasting relay 140 that is
directly coupled to output 130. Blasting relay 140 also contains a
field generator such as an inductor or coil 235 for producing a
field to activate or enable switch 230 under control of relay 145
containing inductor 240 and switch 245.
[0015] FIG. 3 shows a top view of a container or fire box 310 for
the system 100. The fire box 310 contains the LED character 210,
the fire lock out lamp 215, and switches 112, 114, and 116. It also
contains a safety breaker input 315 and blasting cap inputs 320 and
325 which are used to couple the fire box 310 to blasting caps or
other explosive or pyrotechnic devices that may be electrically
activated. It may also be used for firing model rockets or other
recreational devices. In further embodiments, the inputs 320 and
325 may be modified to activate explosives in a different manner,
such as magnetically or hydraulically or in any other manner
desired.
[0016] FIG. 4 is a flowchart showing functions performed by the
controller. In one embodiment, the controller is a microprocessor
running Parallax, Inc. Basic Stamp.TM. software. Other types of
controller and software may be used as is apparent to those of
skill in the art.
[0017] Power to the fire box 310 is provided at 410. The controller
enters into a safe mode 415 by opening relay 145, and ensuring that
relay 135 is open. The display is initialized to display that the
power is on by displaying a character, such as an "A" for a
predetermined amount of time, such as 0.7 seconds, then displaying
blank, followed by an "A" again, followed by "0". Any characters
may be used. A loop is performed, with the display blinking "0",
waiting for the enable switch 112 to be actuated at 420. The
display is then set to "E", blanked, set to "A", blanked again, and
then stet to "F", which blinks in a loop waiting for the enable
count switch 114 to be actuated at 425. When the enable count
switch 114 is actuated, the display displays and "E" and a "C" for
predetermined times, with predetermined delays between, and then
counts down from "9" to "0" one second at a time.
[0018] At count "0", relay 145 is closed to provide a field to
relay 140, one second is waited, and the relay 135 is turned on,
enabling current to flow to the blast cap through relay 140. The
display is also set to "B" to indicate blast. A predetermined time
is then waited, 3 seconds in one embodiment, and the controller
shuts down the field through relay 145 at 440 and shuts down or
removes the current at 445. It then enters the safe mode loop at
415. At any time prior to blasting, the abort switch may be
actuated at 450, resulting in immediate shut down of the field at
440 and current at 445. The order of these shut downs may be varied
in further embodiments. In one embodiment, the blasting cap is
fired and explodes while the relay 135 is turned on and current is
flowing to the blast cap.
[0019] A double safety is provided by the controller shutting down
the field of the blasting relay, and shutting down the blast
current applied to the blasting cap through the blasting relay. In
further embodiments, the controller may be divided into two or more
logical components, each coupled to separate relays to accomplish
the functions. Other types of relays that require two inputs to
trigger may be used to provide the double safety mechanism. One
safety mechanism involves providing a continuous signal that allows
operation of the blasting relay. In one embodiment, this is the
relay that provides current to the coil 235 to create a field and
close the switch. A further safety mechanism is the relay 135 that
must be activated to provide current through the blasting relay 140
to the blasting cap at output 130. In further embodiments, other
types of safety mechanisms are used to enable a switch, and to
provide blasting current to the enabled switch. In yet a further
embodiment, a short in the blasting cap current loop is detected,
causing the controller to shift into the fail safe mode until the
firing sequence is restarted. This detection is performed with a
circuit breaker, such as a five ampere circuit breaker in one
embodiment.
* * * * *