US3797721A

US3797721A - Explosive actuated tool for driving fastening stud

Info

Publication number: US3797721A
Application number: US00273506A
Authority: US
Inventors: T Clumb
Original assignee: Individual
Current assignee: Illinois Tool Works Inc
Priority date: 1972-07-20
Filing date: 1972-07-20
Publication date: 1974-03-19
Anticipated expiration: 1991-03-19
Also published as: CA968901A

Abstract

Explosive actuated tool for driving element by explosive charge comprises barrel having bore therein for positioning element to be driven by tool. Muzzle is provided at one end of barrel, and explosion chamber communicates with bore for receiving percussion ignitable explosive charge whereby when explosive charge is ignited element positioned within bore is driven from muzzle of tool. Closed gas expansion chamber surrounds barrel and communicates with bore solely through plurality of passageways in barrel directly adjacent muzzle of tool so that high velocity gases produced upon ignition of explosive charge are directed into gas expansion chamber through passageways. Gas expansion chamber functions to receive and dissipate high velocity gases to thereby provide relatively silent operation of tool. Ejection structure associated with explosion chamber removes any spent explosive charges that remain after ignition.

Description

[ Mar. 19, 1974 ABSTRACT EXPLOSIVE ACTUATED TOOL FOR DRIVING FASTENING STUD Inventor: Thomas E. Clumb, 5505 N. lllinois St., Indianapolis, Ind. 46208 Filed: July 20, 1972 Appl. No.: 273,506

United States Patent Clumb 8 Claims, 8 Drawing Figures driven from muzzle of tool. Closed gas expansion chamber surrounds barrel and communicates with bore solely through plurality of passageways in barrel directly adjacent muzzle of tool so that high velocity gases produced upon ignition of explosive charge are directed into gas expansion chamber through passageways. Gas expansion chamber functions to receive and dissipate high velocity gases to thereby provide relatively silent operation of tool. Ejection structure associated with explosion chamber removes any spent explosive charges that remain after ignition.

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B n u H a m m L W S m m J H H .5 m N mnum en n n E m m L m a a mi d fl aw n A 1 .t" .l "H" P a t un m ma Mam em m a T .m t a a m C n n f v .u 8 ip n an PT 6560 m .0 .1 mac MD F m E 250 r 6766 H0 19999 n llll r. L h t N i n C 737 m C a8 0 d IA UIF 026 YW J M 000026 f H M M 6774 m 555 5 9 ,1 H [[rL 2332 PA 1 EXPLOSIVE ACTUATED TOOL FOR DRIVING FASTENING STUD BACKGROUND OF THE INVENTION The present invention relates to an explosive actuated tool for driving a fastening stud, and more particularly to an explosive actuated tool that operates in a relatively silent, safe and trouble-free manner.

The present invention relates to an improvement in an explosive actuated tool of the type described and claimed in US. Pat. No. 3,172,123, granted Mar. 9, 1965. As is now well known, explosive actuated tools function to drive a fastening stud element into a workpiece by the expanding gases produced from the ignition of an explosive charge ignited by impact of the stud element against the charge. This tool includes a barrel member having a bore in which the fastening stud element is received, and a chamber communicating with the bore at the inward end thereof is shaped to receive and position a percussion ignitable explosive charge for ignition by the impact received as a result of inward movement of the stud element in the bore. The

impact producing inward movement of the stud element is obtained by forming the bore with a length that is slightly less than the length of the stud element so that the tip end thereof extends outwardly beyond the end of the barrelmember, and by firing the tool with this extending tip end of the stud element held in contact with the work surface into which it is to be driven. Hitting the rear end of the barrel member with a hammer drives the stud element into the bore to ignite the charge by the impact of the stud element against the charge.

The prior art devices in this particular field are plagued with two major problems. One of these involves the noise associated with the actual use of the tool. In many instances, the noise level is so acute upon ignition of theexplosive charge that it may seriously impair the hearing of the operator using the tool or persons close to the location where the tool is being used. The noise level is primarily caused by a muzzle blast of the high velocity gases produced at the time of ignition of the explosive charge.

The other significant problem with the operation of explosive actuated tools concerns the removal of any spent explosive charges that remain in the tool after ignition. For the most part, the particular tool described in above US. Pat. No. 3,l72,l23 functions in such a manner whereby the spent explosive charge casing is removed from the tool by the high velocity gases generated upon ignition of the charge. The charge is sufficiently loosened by the gases whereby removal thereof is easily achieved by inverting the tool and allowing the spent charge to fall from the barrel. However, in some instances, the spent explosive charge becomes lodged within the bore of the tool and removal is quite difficult. Minor machining imperfections which tend to produce a roughened surface on the inside of the barrel easily receive the spent explosive charge casing when the casing is subjected to the high velocity gases. Usually, the charge casings are fabricated from soft metal such as brass, which assists in the problem of the charge casing becoming lodged within the barrel of the tool.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention 2 v to provide an explosive actuated tool for driving a fastening stud or similar object, the tool operating in a manner that avoids the disadvantages of the prior art and the operation being relatively silent, dependable, safe, efficient and trouble-free.

In accordance with the present invention an explosive actuated tool for driving an element by an explosive charge comprises a barrel having a bore therein for positioning an element to be driven by the tool. A muzzle is located at one end of the barrel. An explosion chamber communicates with the bore for receiving a percussion ignitable explosive charge so that when an explosive charge is ignited an element positioned within the bore is driven from the muzzle of the tool. A closed gas expansion chamber surrounds the barrel and communicates with the bore solely through a plurality of passageways in the barrel directly adjacent the muzzle of the tool. High velocity gases produced upon ignition of an explosive charge are directed into the gas expansion chamber through the passageways and the gases are dissipated within the expansion chamber. Ejection structure is associated with the explosion chamber for removing any spent explosive charges that remain after ignition.

Each of the plurality of passageways in the barrel is inclined away from the muzzle of the tool in a direction from the bore to the gas expansion chamber. Moreover, each of the plurality of passageways in the barrel has a frusto-conical configuration with the larger end thereof opening into the gas expansion chamber. Preferably, four passageways are provided in the barrel.

The ejection structure comprises a reciprocable plunger movable within the bore and the explosion chamber of the barrel between a seated position in the explosion chamber and an extended position adjacent the muzzle of the tool. A stem is secured at one end thereof to the plunger, and an operator engages the free end of the stern for urging the plunger to its extendedposition adjacent the muzzle of the tool. The operator may comprise a reciprocable sleeve on the outside of the barrel and a plug onthe inside of the barrel. At least one longitudinal slot extends through the barrel, and a securing device extends through the slot for attaching the inside plug to the outside sleeve for movement therewith. The plug is arranged to engage the stem at the free end thereof when the sleeve is moved toward the muzzle of the tool to thereby eject any spent explosive charges that remain after ignition.

A first biasing device reacts between the barrel of the tool and the free end of the stem for urging the plunger to its seated position in the explosion chamber. A second biasing device reacts between the barrel and the plug for returning the operator to its position furthest removed from the muzzle of the tool.

BRIEF DESCRIPTION OF THE DRAWING Novel features and advantages of the present invention in addition to those mentioned above will become apparent to those skilled in the art from a reading of the following detailed description in conjunction with the accompanying drawing wherein:

FIG. 1 is a side elevational view of an explosive actu ated tool according to the present invention, with the tool positioned just prior to driving the fastening stud into the workpiece;

FIG. 2 is a side elevational view of the tool illustrated in FIG. 1 showing the tool ejecting a spent explosive charge, according to the present invention;

FIG. 3 is a top plan view of the tool shown in FIGS. 1 and 2',

FIG. 4 is a sectional view taken along line 4-4 of FIG. 3 illustrating the tool in the position shown in FIG.

FIG. 5 is a sectional view similar to FIG. 4 but illustrating the tool in the position shown in FIG. 2;

FIG. 6 is a side elevational view of the upper portion of the barrel ofthe tool, according to the present invention;

FIG. 7 is a sectional view taken along line 7-7 of FIG. 5; and

FIG. 8 is a sectional view taken along line 88 of FIG. 2.

DETAILED DESCRIPTION OF THE INVENTION Referring in more particularity to the drawing, an explosive actuated tool 10 comprises a primary barrel member 12 having a bore 14 therein which extends inwardly from the muzzle 16 of the tool. An explosion chamber 18 extends inwardly from the bore 14, and the chamber 18 communicates with the bore 14 from a shoulder 20 at the inner end of the bore. The explosion chamber 18 has a smaller diameter than the bore 14 as reduced by the shoulder 20. As shown best in FIG. 4, the bore 14 is dimensioned to receive a stud 22 or other element to be driven by the tool. The explosion chamber 18 is provided for receiving a percussion ignitable explosive charge, such as a blank cartridge 24, with the inner shoulder 20 providing a seat for the rim 26 of the cartridge. This relationship positions the firing surface 28 of the cartridge outwardly of the cartridge body 24 which extends within the explosion chamber 18.

The stud 22 is provided with a firing pin protuberance 30 extending from the head 32 thereof for contact with the firing surface 28 of the cartridge 24. The head 32 has a diameter slightly less than the diameter of the bore 14 so that upon firing of the cartridge the head 32 serves as a piston to drive the stud 22 from the bore 14 of the tool 10. The tip 34 of the stud 22 is pointed for driving into a workpiece 36, such as a concrete floor or wall or any other type of material or structure. As shown in the drawing, the stud 22 is utilized to fasten an L-shaped bracket 38 to the concrete ceiling 36.

The stud 22 is of an overall length slightly greater than the length of the bore 14 so that when the cartridge 24 and the stud 22 are positioned in the primary barrel 12 of the tool, the tip 34 of the stud extends slightly beyond the muzzle 16. In this manner, the tool is simply actuated by first positioning the tip 34 in engagement with the ceiling 36 and then striking the base end 40 of the tool. This impact forces the stud 22 further into the bore 14. Ultimately, the protuberance 30 on the head 32 of the stud 22 is forced against the firing surface 28 of the cartridge 24 to ignite the cartridge by percussion. The explosion created upon ignition of the cartridge 24 drives the stud 22 into the workpiece 36, as shown in FIG. 2.

As explained above, the firing of the tool 10 of the present invention is accomplished by striking the tip 34 of the stud 22 against the workpiece 36, and this can be done by hitting the base end 40 of the tool, or alternatively by striking the barrel against the workpiece.

With regard to the latter, a hammer handle may be formed on the barrel, if desired.

As shown best in FIG. 4, a guide washer 42 is provided adjacent the tip 34 of the stud 22. The guide washer 42 is slidable on the stud 22 and is initially positioned thereon by a friction fit. The washer 42 functions as a laterally extending flange and fits within a recess 44 at the muzzle 16 of the tool. As shown in FIG. 4, the relationship between the stud 22, washer 42, recess 44 and bore 14 is such that the stud 22 is centered within the bore. When the stud 22 is driven into the workpiece, it slides through the washer 42 which ultimately remains against the Lshaped bracket 38 as a washer for the head 32 of the stud.

A closed gas expansion chamber 46 surrounds the primary barrel 12 of the tool 10 and communicates with the bore 14 solely through a plurality of passageways 48 in the barrel directly adjacent the muzzle 16 of the tool. In operation, the high velocity gases produced upon ignition of the explosive charge 24 are di rected into the gas expansion chamber 46 through the passageways 48, and these gases are dissipated within the chamber. After the tool 10 is fired, the head 32 of the stud 22 seals off the bore 14 at the muzzle 16 whereby the high velocity gases are directed into the chamber 46 via the passageways 48. Preferably, the volume of the chamber 46 is approximately 3.55.5 cubic inches.

Each of the plurality of passageways 48 in the barrel 12 is inclined away from the muzzle 16 of the tool in a direction from the bore 14 to the gas expansion chamber 46. Also, each of the plurality of passageways in the barrel has a frusto-conical configuration with the larger end thereof opening into the gas expansion chamber. This particular orientation and configuration facilitates flow of the high velocity gases into the expansion chamber 46 after the explosive charge is ignited and the stud 22 is driven into the workpiece. Four passageways 48 are provided in the barrel 12, as shown best in FIG. 7.

An ejection arrangement is associated with the explosion chamber 18 for removing any spent explosive charges 24 that remain after ignition. For the most part, the ejection arrangement comprises a reeiprocable plunger 50 movable within the bore 14 and the explosion chamber 18 between a seated or retracted position in the explosion chamber (FIG. 4) and an extended position adjacent the muzzle 16 of the tool (FIG. 5). A stem 52 is secured at one end thereof to the plunger 50, and an operator 54 engages the free other end of the stem for urging the plunger 50 to its extended position adjacent the muzzle of the tool.

A tubular extension 56 threadably connected to the primary barrel 12 forms part of the overall barrel structure. The operator 54 comprises a reeiprocable sleeve 58 on the outside of the barrel portion 56 as well as a plug 60 on the inside thereof. A pair of opposed longitudinal slots 62 extends through the barrel portion 56, and a pin 64 extends through the slots 62 for attaching the inside plug 60 to the outside sleeve 58 so that the plug and sleeve move as a unit when the sleeve reciprocates on the outside of the barrel portion 56. The inside plug 60 is arranged to engage the stem 52 at the free end thereof when the sleeve 58 is moved toward the muzzle 16 of the tool to eject any spent explosive charges that remain after ignition.

A first coil spring 66 reacts between the barrel 12 and the free end of the stem 52. In this regard, an enlargement 68 is attached to the free end of the stem and this enlargement functions as a stop for the spring 66. As is clear from the drawing, the coil spring 66 urges the plunger 50 to its seated position in the explosion chamber 18, and it also functions to return the plunger to that position after it is extended to eject a spent explosive charge. A second coil spring "70 is also provided and it reacts between the barrel l2 and the inside plug 60 of the operator 54. The second coil spring 70 returns the operator 54 to its starting position which is furthest removed from the muzzle 16 of the tool, that position-being shown in FIGS. 1 and 4.

The longitudinal slots 62 in the barrel portion 56 have inclined portions 72 and enlarged openings 74 at the ends thereof furthest removed from the muzzle 16 of the tool. Accordingly, when ejection of a spent explosive charge is desired, the sleeve 53 of the operator 54 must first be slightly turned to thereby position the pin 64 in alignment with the major portion'of the slots 62. Then, the sleeve is urged toward the muzzle 16 of the tool whereby the plunger 50 ejects any explosive charge remaining in the bore 14 after ignition. The inclined end portions 72 and enlarged openings Mprevent inadvertent operation of the ejection arrangement. If the sleeve is longitudinally shifted without being slightly turned the plunger remains seated in the explosion chamber.

The explosive actuated tool of the present invention is relatively simple in construction and includes very few moving parts. In operating the tool, an explosive charge 24 is initially positioned inside the barrel with the rim 26 of the charge seated upon the shoulder 20. The charge is simply dropped in the tool through the muzzle 16. Next, the stud 22 with its guide washer 42 is inserted into the bore 14 untilthe washer is seated within the recess 44 at the muzzle 16 of the tool. Accordingly, when the stud 22 is driven into the bore M, the protuberance on the head 32 of the stud strikes the firing surface of the charge 24 to thereby ignite the charge. The high velocity gases produced upon ignition of the explosive charge drive the stud 22 out of the bore 14 into the workpiece 36. These high velocity gases do not escape through the muzzle of the tool and are instead directed into the gas expansion chamber 46 via the passageways 48 in the barrel 32. As a result, muzzle blast is substantially eliminated, and the operation of the tool is substantially silenced. The head 32 of the stud 22 remains within the bore M until the tool is removed from the workpiece 36 and it functions to seal off the muzzle of the tool whereby the high velocity gases are directed into the gas expansion chamber where they are dissipated.

in most instances, the cartridge shell that remains after ignition is easily removed by simply inverting the tool. However, in some instances, the spent explosive charge 24 becomes lodged within the barrel E2 of the tool and does not fall out upon inversion of the tool. Under these circumstances, the sleeve 58 of the operator 54 is slightly turned to position the pin 64 attached to the sleeve in alignment with the major portion oflongitudinal slots 62. Next, the sleeve 58 is urged toward the muzzle i6 which in turn causes the plunger 50 to eject the spent explosive charge from the barrel 12 of the tool (FlGS. 2 and 5). Coil spring 70 returns the operator 54 including the sleeve 58 and plug 60 to its retracted position shown in lFlGS. l and 4. Finally, the coil spring 66 returns the plunger from its extended position shown in H0. 5 to its seated position in the explosion chamber 118, as shown in PEG. 4. The tool it) is then ready for receiving another explosive charge and another stud.

What is claimed is:

ll. An explosive actuated tool for driving an element by an explosive charge comprising a barrel having a bore therein for positioning an element to be driven by the tool, a muzzle at one end of the barrel, an explosion chamber communicating with the bore for receiving a percussion ignitable explosive charge whereby when an explosive charge is ignited an element positioned within the bore is driven from the muzzle of the tool, a closed gas expansion chamber surrounding the barrel and communicating with the bore solely through a plurality of passageways in the barrel directly adjacent the muzzle of the tool whereby high velocity gases produced upon ignition of an explosive charge are directed into the gas expansion chamber through the passageways and dissipated therein, and ejection means asso ciated with the explosion chamber for removing any spent explosive charges that remain after ignition, the ejection means comprising a reciprocable plunger movable within the bore and the explosion chamber of the barrel between a seated position in the explosion chamber and an extended position adjacent the muzzle of the tool.

2. An explosive actuated tool as in claim 1 including a stem secured at one end thereof to the plunger, and an operator engaging the free other end of the stem for urging the plunger to its extended position adjacent the muzzle of the tool.

3. An explosive actuated tool as in claim 2 wherein the operator comprises a reciprocable sleeve on the outside of the barrel and a plug on the inside of the barrel, longitudinal slot means extending through the barrel, and securing means extending through the slot means attaching the inside plug to the outside sleeve for movement therewith, and the plug being arranged to engage the stem at the free end thereof when the sleeve is moved toward the muzzle of the tool to eject any spent explosive charges that remain after ignition.

4. An explosive actuated tool as in claim 3 including first biasing means reacting between the barrel and the free end of the stem for urging the plunger to its seated position in the explosion chamber, and second biasing means reacting between the barrel and the plug for returning the operator to its position furthest removed from the muzzle of the tool.

5. An explosive actuated tool for driving an element by an explosive charge comprising a barrel having a bore therein for positioning an element to be driven by the tool, a muzzle at one end of the barrel, an explosion chamber communicating with the bore for receiving percussion ignitable explosive charges whereby when an explosive charge is ignited an element positioned within the bore is driven from the muzzle of the tool, and ejection means associated with the explosion chamber for removing any spent explosive charges that remain after ignition, the ejection means comprising a reciprocable plunger movable within the bore and the explosion chamber of the barrel between a seated position in the explosion chamber and an extended position adjacent the muzzle of the tool.

6. An explosive actuated tool as in claim including a stem secured at one end thereof to the plunger, and an operator engaging the free other end of the stem for urging the plunger to its extended position adjacent the muzzle of the tool.

7. An explosive actuated tool as in claim 6 wherein the operator comprises a reciprocable sleeve on the outside of the barrel and a plug on the inside of the barrel, longitudinal slot means extending through the barrel, and securing means extending through the slot means attaching the inside plug to the outside sleeve for movement therewith, and the plug being arranged to engage the stem at the free end thereof when the sleeve is moved toward the muzzle of the tool to eject any spent explosive charges that remain after ignition.

from the muzzle of the tool.

' PaentNo. 3,797,721

521 UNITED STATES PATENT OFFICE T1 I CERTIFICATE OF CORRECTION Dated March 19,, 197A lmilentofls) Th mafl E. Clumb It is certified thaterror appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

on the Front Pagg, insert Assigneei, Ladd Tool Company,

Wilmington, De1.,

Signed and sealed this 8th day of October 1974.

( EAL) Atltest:

MciCOY M. GIBSON JR. I V C. MARSHALL DANN Commissioner of Patents Atftesting Officer

Claims

1. An explosive actuated tool for driving an element by an explosive charge comprising a barrel having a bore therein for positioning an element to be driven by the tool, a muzzle at one end of the barrel, an explosion chamber communicating with the bore for receiving a percussion ignitable explosive charge whereby when an explosive charge is ignited an element positioned within the bore is driven from the muzzle of the tool, a closed gas expansion chamber surrounding the barrel and communicating with the bore solely through a plurality of passageways in the barrel directly adjacent the muzzle of the tool whereby high velocity gases produced upon ignition of an explosive charge are directed into the gas expansion chamber through the passageways and dissipated therein, and ejection means associated with the explosion chamber for removing any spent explosive charges that remain after ignition, the ejection means comprising a reciprocable plunger movable within the bore and the explosion chamber of the barrel between a seated position in the explosion chamber and an extended position adjacent the muzzle of the tool.

6. An explosive actuated tool as in claim 5 including a stem secured at one end thereof to the plunger, and an operator engaging the free other end of the stem for urging the plunger to its extended position adjacent the muzzle of the tool.

8. An explosive actuated tool as in claim 7 including first biasing means reacting between the barrel and the free end of the stem for urging the plunger to its seated position in the explosion chamber, and second biasing means reacting between the barrel and the plug for returning the operator to its position furthest removed from the muzzle of the tool.