US2208780A - Detonator - Google Patents

Description

F. A. WITT A DETONATOR July 23, 1940.

2 Sheets-Sheet 1 Filed Aug. 4, 1938 Patented July 23, 1940 DETONATOR Fred A. Witt, Los Angeles, Calif.

Application August 4, 1938, Serial No. 223,037

13 Claims.

This invention relates to a detonator and more particularly pertains to a mechanism for firing an explosive charge at a remote point in a well or other bore or shaft.

An object of the invention is to provide a detonator which is adapted to be advanced into a bore and then be actuated mechanically to effect ignition of an explosive, and in which the operating mechanism of the detonator is so constructed and controlled as to minimize if not obviate either premature firing of a charge, or in event. of mis-fire, to obviate subsequent accidental firing of the charge.

Another object is to provide an effective means for mechanically controlling operation of the detonator after being advanced into a bore by manipulation of a support on which the detonator iscarried.

Another object is to provide a detonator in which ignition of an explosive is controlled by reciprocal movement of the detonator body relative to the walls of the bore in which it is positioned, and in which a predetermined number of strokes of the detonator body is required in order to efiect ignition of the explosive.

Another object is to provide a construction whereby service operation of the detonator to fire an explosive can only be efiected when it is located in a bore having a diameter for which it is made to fit, such for example as the reduced lower end portion of an oil well.

A further object is to provide a detonator having a firing hammer, in which a detent for the hammer has a screw thread mounting, and in which a ratchet mechanism is employed as a means for retracting the detent with a step by step movement.

With the foregoing objects in view, together withsuch other objects and advantages as may subsequently appear, the invention is carried into eifect as illustrated by way of example in the accompanying drawings, in which:

Fig. 1 is a view in side elevation of the detonator showing it as applied and depicting it as being lowered into the upper portion of a well casing;

Fig. 2 isa view similar to Fig. 1 showing the parts as arranged when the detonator is disposed 50 in the reduced lower end portion of a well casing and with the parts in position in readiness for operation;

Fig. 3 is a view in elevation similar to Fig. 2 showing the parts in an alternative position and as subsequent to operation of the detonator;

Fig. 4 is a detail in horizontal section taken on the line 4-4 of Fig. 2;

Fig, Sis a detail in horizontal section taken on the line 5-5 of Fig. 3 as seen in the direction indicated by the arrows;

Fig. 6 is an enlarged detail invertical section taken on the line 6--6 of Fig. 1 as seen in the direction indicated by the arrows and showing the parts in a'normal position;

Fig. 7 is a detail in horizontal section taken on the line l! of Fig. 6;

Fig. 8 is a detail in section taken on the line 88 of Fig. 6;

Fig. 9 is a view in section and elevation with parts broken away as seen on the line 9-9 of Fig. 8, in the direction indicated by the arrows;

Fig. 10 is a view in section and elevation as seen on the line I0l0 of Fig. 8 in the direction indicated by the arrows.

Referring to the drawings more specifically A indicates generally the body of the detonator Which is preferably cylindrical and embodies a tubular upper section IE to which is det'achably connected a lower end section t5 as by means of an exteriorly threaded nipple IT on the lower end of the upper section i5 which is screwed into engagement with an interiorly threaded socket [8 formed in the upper end of the lower section IS. The nipple I? is formed with a bore 19 slightly larger than the internal diameter of the upper section l5in which is arranged a sleeve 20 having an inwardly tapered bore 2| and which sleeve abuts a shoulder 22 at the bottom of the bore I9. A tapered plug 23 fastened on the end of a cable 24 extending through the upper section l5 seats in the sleeve 20 in wedge engagement therewith to afford a connection between the cable 24 and'the detonator A and whereby the detonator may be lowered into a well casing B by the cable 24 and be suspended therein as indicated in Figs. 1, 2 and 3.

The lower end section iii of the 'detonator is formed with a diametrically extending bore 25 having enlarged internally threaded outer end portions for the reception of socket plugs 26 and 21, and is also formed with an internally threaded bore 28 extending perpendicularly to the bore 25 and opening thereto intermediate the ends thereof.

The plug 21 is formed with a tubular extension 29 of a diameter slightly less than that of the bore 25, the outer end of which extension is adapted to receive an explosive cap 30 here shown as comprising a blank cartridge, and the inner end of which extension constitutes a firing chamber 3| which is formed with apertures 32 communicating with a fire passage 33 leading to an explosion chamber 34 in the lower end of the section l6.

The explosion chamber 34 is temporarily closed by a diaphragm 35 held in place against a shoulder 36 by an externally threaded demountable ring 31 screwed into the lower end portion of the lower section IS. The explosion chamber 34 is designed to contain an explosive, such as gun powder, adapted to. be fired by a flame emitted from the passage 33. A normally open check valve 38 is interposed between the explosion chamber 34 and the adjacent end of the passage 33 and is adapted to close the passage 33 on exploding of a charge in the explosion ..chamber 34 to prevent escape of the resultant expanding gases in chamber 34 will have a shearing action on the diaphragm.

Slidably encompassing the inner end of the cartridge receiving extension 29 is a sleeve 39 fitted with a firing pin 40 arranged to strike the cap of the cartridge 30 and mounted in the portion of 'thebore 25 extending between the sleeve 39 andthe "plug 26 is a reciprocal sleeve 4| fitted on its inner end with a hammer 42 arranged to strikethe cap sleeve 39. Bearing between the sleeve 4| and the plug 26 is a coil spring 44- adapted 'tobe placed under tension on retraction of the sleeve 4| and to act to advance the latter to effect firing of the cartridge 30 through the hammer'42 and cap sleeve 39.

As a'ineans for holding the sleeve 4| in a retracted position in opposition to the spring 44, a

shiftable'pin detent 45 is extended through a packing gland 46 mounted in the bore 28, the innerend of which detent is positioned in front of the forward or inner end of the sleeve 4| when the latter is in a retracted position. The outer end of the detent 45 is affixed to an externally threaded hub 41 in the interior of a hollow hexagonal nut 48, which hub is screwed into engagement with an internally threaded extension 49 of the packing gland 46 whereby rotation of the nut48 will effect either advance or retrograde movement of the detent 45 to move the latter in and out of engagement with the spring pressed Encircling the nut 48 and disposed in a recess 50 in the section' I6 is a ratchet disc 5|, particularly shown in Fig. 10, having a central opening conforming to the nut 48 whereby rotation of the disc 5| will effect corresponding movement of the nut. The outer margin of the disc 5| is formed with recesses 52 arranged to be engaged by a ball detent 53 which bears against the edge of the disc 5| under the urge of a spring 54 seating in. a bore 55 formed in the'section IS. The disc 5| is formed on its outer" face with a. series of arcuate channels 56 having inclined bottom walls and end shoulders 51, and which channels and shoulders constitute elongated ratchet teeth.

Revolubly mounted in the recess 50 is an arcuated disc 53 which is supported on ball bearings 59 interposed between the periphery of the disc 58 and the side walls of the recess 50. A spring pressed pawl 60 carried by the disc 58 projects into cne or the arcuate channels 56 of the ratchet disc 5| to abut the shoulders 51 thereof; the pawl movable successivelyinto engagement with the several shoulders 51 to effect rotation of the disc 5| with a step by step movement on eifecting oscillation of the actuating disc 58. This move merit of the disc is effected by means or a sleeve 6| completely encircling the section l6; the sleeve 6| being formed with a circumferential channel 62 on its inner periphery with which is engaged a pin 63 protruding from the outer face of the disc 58 in oii-set relation to the vertical center of the latter.

Revolubly encircling the upper end portion of the section i5 is a sleeve 64 which is connected to the sleeve 6| by a series of spring strips 66, which strips constitute grips for engaging the inner surface of the well casing B to hold the sleeves 6| and 64 stationary relative to the detonator sections l5 and I6, whereby the latter may be reciprocated collectively in relation to the rings when the strips 65 are in their gripping engagement with the casing.

As a means for limiting relative movement or the detonator sections and the sleeves 6|64, a series of pins 66 and 61 are arranged on the sections I5 and I6 respectively to project therefrom below the sleeves, and pins 68 are arranged to project from the section i6 above the lower sleeve 6|; the pins 61 and 68 being spaced apart a distance exceeding the width or the sleeve 6| to permit the requisite relative movement of the detonator body and the sleeves. The pins 66 are spaced from the pins 68 a distance substantially corresponding to the normalspacing of the sleeves BI and 64, as shown in Fig. 1, and primarily serve as safety stops to prevent collective movement of the sleeves longitudinally of the detonator body when the strips 66 are in their normal expanded position and whereby operation of the detonator is prevented until inward contraction of the strips. 65 is efiected as shown in Figs. 2 and 3 and which contraction acts to increase the spacing between the sleeves 6| and 64.-

The sleeve 6| is formed with an opening 69 leading to the channel 62 through which the pin 63 may be passed and engaged with the disc 58 and thus be disposed in engagement with the channel 62; the pin 63 being formed with a threaded stem 10 whereby it may be screwed in place. The pins 68 are removable to permit the sleeve 6| being moved to a position to clear the disc 58 to give access to an opening 1| therein through which a tool may be engaged with a socket 12 in the nut 48 to effect manual rotation thereof in setting the detent 45. Shifting of the sleeve 6| also affords access to the plug 21 to permit removal and replacement thereof in loading the sleeve 29 with the cartridge 30 and in eflecting reengagement of the sleeve 4| with the detent 45. p

The lower end section iii of the detonator may be attached to any suitable mechanism to be operated by the firing of the cap 30, or of the explosion of the charge in the explosion chamber 34, but is here shown as adapted for connection to the'upper end of a tube 13 embodied in the well cleaning device set forth in an application Serial No. 223,036 for Letters Patent filed coincident herewith, and in which device expanding gases formed by exploding the charge in the explosion chamber 34 will be directed into the interior of the tube 13 on rupturing the 'diaphragm 35 and then be caused to efiect expansion of an elastic sleeve 14 encompassing the tube I3. As here shown the tube 13 is internally threaded and is screwed into engagement with an externally threaded nipple 15 formed on the lower end of the section l6 and in which the explosion chamber 34 is formed.

In the operationv of the invention a suitable explosive material is placed in the chamber 34 when the tube 13, ring 31 and diaphragm 35 are detached, whereupon these parts are replaced.

The sleeve 6| is then retracted after removal of the pin 63 through the opening 69, whereupon the plug 21 is removed and the sleeve 4| of the firing hammer retracted in opposition to the spring 44 by insertion of a suitable tool the outer end of the then opened bore 25. The nut 48 is then turned to advance the detent 45 to project in front of the inner end of the sleeve 4|.

A cap 30 is placed in the sleeve 29 and the firing pin sleeve 39 is put in place thereon, whereupon the plug 2l'-is remounted.

Although the detonator is now loaded, the cap 30 cannot be fired until the detent 45 has been retracted clear of the hammer sleeve 4|, and

which cannot be accomplished without rotation of the nut 48 one or more turns. In this instance rotation of the nut 48 is designed to be eifected by relative reciprocal movement-of the detonator body A and the sleeve 6| but which movement is efiective to turn the nut 48 only when the pin 63 is engaged in the channel 62 of the sleeve 6|. As a matter of safety the placing of the pin 63 may not be effected until the detonator is about to be lowered into a well.

n placing the pin 63 in position in the channel 62 of the sleeve 6| and restoring the stop pins 68, the device is conditioned for operation and which operation is carried out by lowering the detonator into a well casing B by means of the cable 24, as particularly shown in Fig. 1; the detonator being lowered through the enlarged upper portion of the well casing B where the spring strips 65 have little or no gripping action on the casing unless especially designed for such purpose; the spring strips 65, however, being ordinarily formed so that when the detonator is lowered .into a reduced lower end portion of the well casing B, as shown in Fig. 2, the spring strips will be contracted under tension and thereby be caused to effect a gripping action on the inner periphery of the casing.

By this arrangement the detonator may be operated only when positioned in a bore sufliciently small to afford a gripping action on the strips 65 and also eiiect such inward compression thereof as to increase the spread of the sleeves 6| and 64, and whereby the possibility of unwanted firing of the detonator in a well is practically eliminated. 4

As the detonator body A moves downward the rings 6| and 64 will lag by reason of the drag of the spring strips 65 on the casing wall; the ring 6| then abutting the stop pins 68 so as to limit upward movement of the ring 6| on the detonator and causing the ring 64 to move to a position spaced above the pins 66. The rings 6| and 64 will then be spaced from the pins 61 and 66 respectively as shown in Fig. 2.

On thus lowering the detonator into the desired position in the well casing the detonator body A is reciprocated relative to the rings 6 |-64 by raising and lowering the cable 24, which action operated through the pin 63 engaged by the sleeve 6| to eifectoscillation oi the disc 58 with a resultant step by step movement of the ratchetdisc by reason of the pawl 60 successively engaging the shoulders 51 on the disc 5|. 5- This movement of the disc 5| effects correspondingmovement of the nut 48, and acts to retract the latter'so as to draw the detent 45 out of engagement with the sleeve 4| with a step by step movement so that the spring 44 will act to suddenly advance the latter and impact the hammer 42 thereon against the firing sleeve 39 and cause the firing pin 40 thereof to explode the cap 30. Firing of the cap effects propagation of a fiarne in the passage 33 and the resultant ignition of the explosive material in the explosion' chamber 34 which exploding material will burst. the diaphragm '35 so as to direct expanding gases into the tube 13. It will be understood, however, that firing of the cap may be employed to fire any other desired explosive charge.

On having completed the firing operation as stated the detonator may be withdrawn from the well and reloaded as before described.

-An important feature of the invention resides in the provision of the ratchet control of the firing pin which permits of a series of up and down movements of the detonator body relative to the control sleeves GI and 64 without effecting firing of the charge, since in lowering the detonator into the well casing it is sometimes necessary to repeatedly raiseand lower, the detonator before it reaches the firing position and on the other hand a predetermined number of reciprocations of the detonator is necessary in order to efiect a firing action.

While I have shown and described a specific embodiment of my invention, I do not limit myself to the exact details of construction set forth, and the invention embraces such changes, modifications and equivalents of the 'parts and their formation and arrangement as come within the purview of the appended claims.

I claim:

1. In a detonator, a body having a firing chamber, a cap holder in said chamber, a firingpin for exploding a cap in said holder, a spring pressed hammer for actuating said firing-pin,

a, detent for engaging and holding saidv ham.- mer in a retracted position; and means for moving said detent step by step to a position out of engagement with said hammer including a ratchet, a connection between said ratchet and detent, a pawl engaging said ratchet, an oscillatory disc carrying said pawl, a sleeve slidably carried on said body, and engaging means between said sleeve and disk for imparting step by step movement to said disk on relative reciprocation of said sleeve and body.

2. The structure called for in claim 1 together with well casing engaging means connected with said sleeve to hold the latter stationary relative to said body, and a support for said body through which the latter maybe reciprocated relative to said sleeve.

3. In a detonator, a body, a cable support for said body by which it may be lowered into a well casing and withdrawn therefrom, a sleeve loosely carried on and encircling said body, means for limiting relative movement of said body and 70 sleeve in the direction of the length of the latter,

a cap carrier in said body, and means actuated by relative reciprocal movement of said body and sleeve for firing a cap in said carrier.

4. In a detonator, a body, a cable support for 75 said body by which it may be lowered into a well casing and withdrawn therefrom, a sleeve loosely carried on and encircling said body, means for limiting relative movement of said body and sleeve in the direction of the length of the latter, a cap carrier in said body, and means actuated by relative reciprocal movement of said body and sleeve for firing a cap in said carrier including a ratchet, a firing-pin controlled by said ratchet, and an operating connection between said sleeve and ratchet.

5. In a detonator, a body, a cable support for said body, a sleeve slidably carried on said body, means for holding said sleeve stationary relative to said body, a spring pressed firing hammer in said body, a detent for holding said hammer in a, retracted position, a screw threaded mounting for said detent, and means connected with said sleeve for moving said detent on its threaded mounting by relative reciprocation of said sleeve and said body.

6. -In a detonator, a body having a flre passage, a cable support for suspending said body, a sleeve loose on said body, means limiting relative movement of said body and sleeve, means for holding said sleeve stationary in a well bore in which the body is suspended, a ratchet carried by said body and connected to said sleeve, said ratchet being movable step by step on reciprocating said body relativeto said sleeve, and means controlled by said ratchet for propagating fire in said passage. I

7. In a detonator, a body having a fire passage, a cable support for suspending said body, a sleeve loose on said body, means limiting rel-' ative movement of said body and sleeve, means for holding said sleeve stationary in a well bore in which the body is suspended, a ratchet carried by said body and connected to said sleeve, said ratchet being movable step by step on reciprocating said body relative to said sleeve, and means controlled by said ratchet for producing fire in said fire passage including an explosive cap, a hammer for exploding said cap, a detent for said hammer, and a connection between said detent and ratchet.

8. In a detonator, a body having an ignition chamber, a cap support in said chamber, a hammer for exploding a cap in said support, a detent for said hammer, a screw thread mounting for said detent, and means for imparting intermittent rotary motion to said detent, to effect step by step retraction thereof including a turnable ratchet ring connected to said detent, a pawl engaging said ring, a turnable disc on said body carrying said pawl, and means carried on said body for effecting. oscillation of said disc.

9. In a detonator, a body having an ignition chamber, a cap support in-said chamber, a hammer for exploding a cap in said support, a detent for said hammer, a screw thread mounting for said detent, and means for imparting intermittent rotary motion to said detent, to effect step by step retraction thereof including a turnable ratchet ring connected to said detent, a pawl engaging said ring, a turnable disc on said body carrying said pawl, a sleeve loosely encircling said body having. an internal peripheral channel, and a pin on said disc extending into said channel.

10. In a detonator, a body having an ignition chamber, a cap holder in said chamber, a spring pressed hammer for exploding a cap in said holder, a detent for holding said hammer retracted, a screw threaded hub carrying said detent, a threaded collar carried by said body in which said hub is screwed, a turnable ratchet ring carried by said body, means for inter-engaging said hub and ring, a ball detent engaging,

said ring, a turnable disc on said body, a pawl on said disc engaging said ratchet ring, a demountable pin on said disc, a sleeve loose on said body with which said pin is engageable, means connecting with said sleeve engageable with an encompassing wall to hold said sleeve stationary relative to said body, and means for suspending said body by which it may be reciprocated relative to said sleeve.

11. In a detonator, a body member having an explosion chamber therein, a pair of spaced sleeves slidably carried on said body member, stops on said body member contiguous the adjacent ends of said sleeves normally holding said sleeves against movement longitudinally of said. body member; compressible means engaging said sleeves for spreading said sleeves relative to each other and to said stops, and means actuated by one of said sleeves for igniting an explosive in said chamber.

12. In a detonator, a body member having an explosion chamber therein, a pair of spaced sleevesslidably carried on said body member, stops on said body member contiguous the adjacent ends of said sleeves normally holding said sleeves against movement longitudinally of said body member, outwardly bowed spring strips connecting said sleeves adapted to be pressed inwardly to spread said sleeves relative to each other and to said stops to render said sleeves movable longitudinally of said body, and means operable by such movement of one of said sleeves for igniting an explosive in said ignition chamber.

13. In a detonator, a body member having an explosion chamber therein, a pair of spaced sleeves slidably carried on said body member, stops on said body member contiguous the adjacent ends of said sleeves normally holding said sleeves against movement longitudinally of said body member, outwardly bowed spring strips connecting said sleeves adapted to be pressed inwardly to spread said sleeves relative to each other and to said stops to render said sleeves movable longitudinally of said body, a ratchet mechanism, means for actuating said ratchet mechanism with a step by step movement by reciprocating said body member relative to one of said sleeves, and means controlled by said ratchet mechanism for firing an explosive in said explosion chamber.

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