US3046557A - Explosively actuated tool - Google Patents

Description

July 31, 1962 s. H. BROUGHTON ETAL 3,046,557

ExPLosIvELY ACTUATED TooL Original vFiled May 17, 1954 4 Sheets-Sheet 1 Q' ln n I 5N roN N Y'. 9 Q

' INVENToRs SIDNEY H. BROUGHTON BYIRGINIUS R.ER|CKsoN July 31, 1962 s. H. BROUGHTON ETAL 3,046,557

EXPLOSIVELY ACTUATED TOOL original Filed may 1.7, 1954.

4 Sheets-Shaei: 2

INVENToRs SIDNEY H. BRoUGHToN IBGINIUS R. ERICKSON Mw, mm 4% ATTO R N EWYS July 31, 1962 s. H. BROUGHTON ETAL 3,046,557

EXPLOSIVELY ACTUATED TooL,

Original Filed May 1.7, 1954 4 Sheets-Sheet 3 INVENTORS SIDNEY H. BROUGHTON BxYIRGlNIUS R. ERICKSON @j MMMMM` ATTORNEYS `July 31, 1962 s. H. BRouGHToN `ETAL 3,046,557

EXPLOSIVELY ACTUATED TOOL 4 Sheets-Sheet 4 @riginal Filed May 1.7, 1954 s WWK ,v n MUR N VOR R NRE O IBR. n H. A YS Mw DW SG mm m VW Nmlj nite @tace tent 3,046,557 Patented July 31, 1962 3,445557 EXPLOSIVELY A-CTUATED TOOL Sidney H. Broughton and Vrginius Robert Erickson, Portland, Oreg., assignors, by mesne assignments, to Omarlr Industries, Inc., a corporation of Oregon Griginal application May 17, 1954, Ser. No. 430,288, now Patent No. 2,773,259, dated Dec. 11, 195o. Divided and this application Nov. 5, 1956, Ser. No. 628,945

7 Claims. (Cl. lult-4.5)

This invention relates :to devices or ,tools which employ an explosive char-ge for forcibly imbedding fastening elements, such as bolts, studs and the like, in masonry or in other hard or semi-hard `Surfaces and substances. This application is la division of :our copending application Serial No. 430,288, tiled May 17, 1954, now Patent No. 2,773,259 granted December l1, 1956.

The use of eXplosively driven projectiles in the form of bolts and studs for the purpose of providing anchoring or `fastening elements on such structures as concrete walls, for example, is well known, and various devices or tools have been developed for this purpose. Such tools employ explosive'ly driven projectiles and are provided with ltiring mechanism generally of more or less familiar type.

An explosively actuated tool of the general type with which this invention is concerned may be used for imbedding elements into Walls or other bodies of different density. If, for example, the density of the work surface is considerably less than that of ordinary concrete, the use of the same `explosively driven projectiles suitable for ordinary concrete would be likely to result in the projectile being driven too far into the work `and thus being driven in so far that it would be of no use as `a fastening element.

Accordingly, another object of the invention .is to provide `an explosively actuated tool in which the force with which -a given ex-plosively driven projectile is driven into the work can be adjusted and modified to some extent in a simple `and practical manner whenever this is necessary.

While generally the work in which the projectile or fastening element Iis required to be imbedded has a continuous at surface and the muzzle end of the gun barrel of the tool is held against such surface and approximately perpendicular thereto, it is sometimes necessary for a fastening element to be secured in a recessed portion of a surface. A further object of the present invention is to provide an improved explosively actuated tool in which the gun barrel muzzle can be held in a recess while the protective means, previously mentioned, at the same time can be held against the outer face of the work around the recess in order to alford the desired protection against any particles which may be dislodged in the recess in the operation of the tool and which particles otherwise might be forcibly ejected from the recess and thus constitute a dangerous hazard to the operator or to any other persons standing nearby.

An additional object of the invention is to provide an improved explosively actuated tool having a gun barrel and associated suitable firing mechanism so arranged that the tool cannot be tired unless the barrel is pressed against the portion of the work in which the projectile is to be imbedded; and further with the firing mechanism so controlled that it cannot then be fired by the operator unless the operator releases a safety control with one hand while yhe actuates the trigger with the other hand, thus making impossible any inadvertent tiring or discharging of the tool.

A still further object of the invention is to provide an explosively actuated tool which will accomplish the previously indicated objects, and which must be opened each time for loading, the opening requiring special manipulation on the part of the operator, and from which a previously fired cartridge will be automatically ejected upon the opening of the tool. v

The construction and manner of operation of our improved explosively actuated tool and the means by which these mentioned objects and other advantages are achieved will be briefly described and explained with reference to the accompanying drawings.

In the drawings:

FIGURE 1 is a sectional elevation taken longitudinally yalong the approximate center line of the device showing the device loaded with a projectile to be explosively driven, but with the device `shown prior to bein set for tiring;

FIGURE 2 is a similar sectional elevation showing the device set for tiring;

FIGURE 3 is an end elevation taken from the right of FIGURE l showing the front face of the safety pad attachment, which safety pad is placed `against the work in the ordinary use of the device;

FIGURE 4 is a vertical sectional View taken on line 4 4 of FIGURE 1 FIGURE 5 is a fragmentary vertical sectional view taken along the longitudinal section of the muzzle end of the gun barrel of the device and through the safety pad, and illustrates the manner -in which the safety pad will accommodate 4a slight tilting of the barrel with respect to the work surface during the firing of the device;

FIGURE 6 is a fragmentary vertical sectional view corresponding in part to the left hand portion of FIGURE 2, but showing the position of the trigger and related members of the tiring mechanism when the device is being tired;

FIGURE 7 is a fragmentary vertical section taken on line 7 7 of FIGURE 2;

FIGURE 8 is a corresponding vertical fragmentary lsection talc-en on line 8-8 of FIGURE 6;

FIGURE 9 is a fragmentary horizontal sectional view taken on line 9-9 of FIGURE 7 and looking upwardly as indicated by the arrows;

FIGURE 10 is a perspective view of the entire device viewed from the opposite side;

FIGURE 11 is a fragmentary horizontal sectional View taken on line 11--11 of FIGURE 6;

FIGURE 12 is a fragmentary side elevation of the rear or handle end of the device with a portion broken away and showing the breech end of the gun barrel, and also illustrating the device as partly opened preparatory to the ejecting of the empty cartridge and the reloading of the device;

FIGURE 13 is a similar fragmentary side elevation corresponding to FIGURE 12, with a portion similarly broken away and shown in section, but showing the device fully opened and the empty fired cartridge in the process of being ejected; v

FIGURE 14 is a fragmentary vertical sectional vview taken on line -14-14 of FIGURES 1 and 2;

FIGURE 15 is a fragmentary side elevation, with portion Vbroken away, taken from the left of FIGURE 14;

FIGUR-E 16 is a'fragmentary horizontal section taken online 16-16 of FIGURE 15; and

FIGURE 17 is a vertical sectional view corresponding in part to FIGURES 1 and 2, but showing the muzzle portion of the gun barrel pressed into extended position beyond the safety pad for special use in discharging a projectile into a recess in the work.

Referring iirst to FIGURES 1, 2 and 10, the housing for the device is made up of three separate portions, namely, the handle portion 10, the intermediate portion 11, and a front end sleeve portion 12. The gun barrel 13` of the device extends through housing portions 11 Yand 12 and both of such housing portions are longitudinally slidable to a limited extent relative to the gun barrel. The muzzle end of the gun barrel preferably has a removable tip 14, which tip has a bore coinciding with the gun barrel bore and which tip also has two or more radially extending exhaust gas ports located at the approximate relative distance from the end of the tip 14 shown in FIGURES 1 and 2. Although the tip 14 could constitute an integral part of the muzzle end of the gun barrel we prefer to have the tip removable so that it can be easily replaced in the event of damage or excessive wear in the course of the use of the device.

The outer end of the sleeve portion 12 of the housing has an integral eccentric circular flange 16. A square shaped housing or shield 17, having an off-center circular opening of slightly less diameter than that of the flange 16, is rotatably mounted on the circular flange 16 by means of a circular disc 16A, attached to the flange 16 by suitable rivets (not shown) and having lugs 16B (FIGURE 4) which engage the underside of the housing 17 around the circular opening in the housing. The

housing 17 is formed with a wall 17 extending around all four sides. Due to the fact that the circular flange 16, on which the housing 17 is mounted, is eccentric with respect to the gun barrel 13 and also due to the fact that the housing 17 is eccentric with respect to the circular flange 16, the housing 17 can be rotated with respect tO the gun barrel muzzle so as to bring the gun barrel muzzle either close to an edge of the housing 17 or at the center of the housing 17. FIGURES 3 and 4 show the gun barrel muzzle at the center of the housing 17. The reason for having the housing 17 movable and adjustable with respect to the gun barrel channel will be explained later.

A square plate 18 (FIGURES l, 2 and 5), slightly smaller than the housing 17, is mounted in the housing 17 by means of four mounting pins 19, located at the four corners of the plate 18, which pins extend freely through slightly larger apertures in the top of the housing 17. These pins terminate in enlarged heads in order to prevent the plate 18 from dropping away from the housing 17. A coil spring 20 is carried on each pin 19 and held under slight compression between the plate 18 and the housing 17. The plate 18 has an olf-center circular opening corresponding to and in registration with the olf-center circular opening in the housing 17.

A second plate 21, which is circular and the diameter of which is less than the diameter of the circular opening in the plate 18, is located in the opening, and this second plate is similarly mounted in the housing 17 by similar pins 22 which extend through the flange 16 and disc 16A. Coil springs 23 are similarly mounted on the pins 22.

A pad 24, preferably of resilientV material such as rubber, covers the outer face of the plate 18 and is secured to the surface of the plate. A similar pad covers the second plate 21 and is secured to the second plate. The pad 24 is preferably formed with a rim shoulder 24 at its periphery and the pad 25 is similarly formed preferably with a rim shoulder 25' at its periphery.

The breech end of the gun barrel 13 is secured to a barrel block 26 on which the housing portion 11 of the device is slidable to a limited extent. A sleeve 27, mounted on the central portion of the gun barrel, has one end held in a recess in the block barrel 26 and the opposite end held in engagement with a ring 28, the ring 28 in turn being held in place on the gun Ibarrel by a locking ring 29. The sleeve 27 extends through a wall partition 30 which is secured within the housing portion 11, and the wall 30 slides on the sleeve 27 when the housing portion 11 is moved with respect to the gun barrel. Similarly, the front housing sleeve portion 12 of the device is slidable on the ring 28. A coil spring 31, held under compression between the wall 30 and the ring 28, normally holds the housing portion 11 in the position shown in FIGURE 1, with reference to the gun barrel, but permits the housing portion 11 to he moved forwardly with respect to the gun barrel against the force of spring 31 (thus towards the right as viewed in FIG- URE l), to the position illustrated in FIGURE 2. A shoulder 27 on the sleeve 27 limits the forward movement of the housing assembly with respect to the gun barrel by engaging the wall 30.

The front end sleeve portion 12 of the housing and a ring band 60 secured in the front of the housing portion 11 are relatively slidable with respect to each other. The ring band is rrnly held in the end of the housing portion 11 by a latch member 61, which, in turn, engages a locking notch in the ring 60. The inner end of the sleeve portion 12 has a rim flange 62 which engages the ring 60 when the sleeve portion 12 is in the normal position shown in FIGURE l. A spring 64, extending around the muzzle portion of the gun barrel, is held under compres' sion between the ring 28 on the gun barrel and the disc 16A which is secured to the flange 16 of the sleeve portion 12. A spring-controlled lever lock 63 ordinarily limits the extent to which the housing portion 11 can be moved forwardly with respect to sleeve portion 12.

As will be later explained, before the device can be fired the housing assembly must be thrust forwardly against the force of springs 31 and 64 from the position of FIGURE l to the position of FIGURE 2. This is done by placing the muzzle end of the gun barrel (or the end of the tip 14 when the gun barrel is equipped with the removable tip) against the work W (FIGURE 2) and pressing the device against the work suihciently to cause the housing portion 11, and with it the handle portion 10, to be pushed forwardly the necessary distance for bringing the device into position for tiring. While this is done the pads 24 and 25 on the springmounted plates 18 and 21 will be held pressed against the work as illustrated in FIGURE 2. In such position the pads 24 and 2S with their surrounding housing 17 will act aS a protection to the operator and to any bystanders against any fragments or particles which may be dislodged from the work around the gun barrel muzbzle as a result of the tiring of the device, for any such dislodged fragments will strike against the pads 24 or 25 and be restrained by the pads. The rim shoulders 24 and 25 on the forward face of the pads furthermore will prevent any possibility of such fragments being discharged laterally between the pads and the work surface. The pads 24 and 25 with their rim shoulders, are held against the surface of the work not only by their springs 20 and 23 but, during the tiring of the device, some of the high velocity air and gases will pass through the ports 15 at the muzzle end of the gun barrel and will momentarily cause pressure to be exerted on the rear face of the plates 18 and 21 within the housing 17 and thus exert additional force to keep the pads 24 and 25 rmly pressed against the work as the projectile is driven into the work.

Even though the device is held by the operator at the time of the tiring of the same, in such way that the gun barrel is inadvertently tilted slightly out of the desired position of perpendicularity with respect to the work surface, and thus if the gun barrel should be held in the manner illustrated in FIGURE 5, the plates 18 and 21 and their pads 24 and 25, due to the fact that the pins 19 and 22 are loosely mounted in the housing 17 and ange 16 respectively, will nevertheless accommodate themselves to any such slight inclination of the gun barrel with respect to the work surface and thus continue to perform their function of preventing any fragments from flying away from the work surface.

Ordinarily the housing or shield 17 and the protecting pad 24 are arranged as shown in FIGURES 3 and 4, thus with the gun barrel centrally located with respect to the pad and its surrounding housing. However, there may be occasions when the projectile is required to be driven into the work adjacent a wall extending at right angles to the work. In such case, the housing 17, and with it the plate 1.8 and pad 24, `upon lbeing rotated 180 with respect to the gun barrel and `the ange 16, will cause one outside edge of the pad 24 and housing to be brought close to the gun barrel, thus enabling the gun #barrel to be positioned in close proximity to the intersection of such wall with the work surface.

A ybreech yblock 32 (FIGURES l, 2, 6, 7, 8, 14 and 16) is positioned in the handle portion .til of the housing assembly, and the handle portion isslidable to a limited extent on the breech block 32. This breech block is U-shaped in horizontal cross section, having two separated extending portions 32', shaped in the form of cylindrical segments, which are positioned within extended side portions 16 (FIGURES 13 and 16) of the housing portion 16. A lug 33 (FIGURES l?, `and 13) extends outwardly from `one of these portions `32. of the breech block and extendsthrough a slot 34 in the corresponding housing extension dit. The engagement of the lug 33 with the ends yof the slot 34 limits the travel of the handle portion 1() with respect to the breech block 32. The two extending portions 32 of the breech block 32 are positioned respectively -adjacent the at sides of the barrel block 26 at the breech end of the gun barrel ( FEGURES 13, 14 and 16), yand these portions 32', and with them the yblock `.32.jand handle 10, are pivotally mounted on the barrel block 26 by means of the pivot pin 35 (FIGURES l, 2, 6 and l2) by which the portions 32 are connected to the barrel block 26.

A rod 36 (FIGURES l2 and 13) extends longitudinally through the barrel block 26 and is slidable therein and is also slidably mounted in the housing wall 39. This rod 36 has an enlarged head which is located Within a recessed chamber 37 in the housing portion 11 and engages -a coil spring 3S. The `opposite end of this rod 36 is arranged for engagement with a recess 39 (FIGURE i2) in the middle lbody portion of the breech block 32. The arrangement is such that the rod 39 prevents any pivoting of the breech block 32 and handle portion 1)y with respect to the barrel block 26 and housing portion 11 until the handle portion lIitl of the housing assembly and `the portion l1 are iirst pulled a maximum distance apart from each other, which results in thrusting the housing portion 11 forwardly with respect to the gun barrel and pulling thev handle portion 16, and with it the barrel block 26 and gun barrel as far as possible in the opposite direction, as illustrated in FIGURE 12. When this is done the handle portion of the device can then be pivoted with respect to the rest of the device and thereby bring the device into 'the `opened position illustrated in FIGURE 13.

A cartiidge ejector plate 40 (FIGURES 1, 13, 14, 15 and 16), normally seated in -a corresponding recess in the rear face of lthe barrel block 26, is mounted on a rod 41 which is slidable in a bore in the barrel block 26. A pin 42, `secured to the rod 41 and extending at right angles from the rod 41, slides ina slot 43I in the ybarrel block 26 and extends a slight distance beyond the side face of the barrel block 26 as shown in FIGURE 16. A coil spring 44 engages the pin 42, land normally holds the pin 42` and rod 41 and ejector plate 46 in the position illustrated in FIGURES 15 and 16.

An arm 44 (FIGURES 13, 15 and 16), located in a recess 45 on the face of one of `the portions 32 or" the breech block l32 and opposite the slot 43, which arm 44 is pivotally supported in the recess 45 for limited movement, is so shaped and arranged (as shown best in FIG- URES 13 and l5) that, when lthe device is opened and the handle portion 10 including breech block 32 is swung down (in counter-clockwise direction, as viewed in FIG- URE 15, and in clockwise direction, as viewed in FIG- URE 13), `the arm 44 will normally engage the pin 42, pushing the pin 42, and with it Ithe rod 41 and ejector plate 40 against the force `of spring 44 and thrusting the plate 40 into the ejectng position shown in FIGURE 13. However, as the handle portion is rotated downwardly still further, the arm 44 then slips out of engagement with the pin 42 and the plate 46 will be returned to its normal position by the yforce of thespring 44. The ejector plate dit is formed With a curved shoulder along `its 'bottom edge which is concentric with the gun barrel channel and which is adapted for engagement' with the rim of the head of the cartridge C as shown in FIGURES 1 and 13.

The l'breech block V32 (FIGURES l, 2 and 6) has a bore to accommodate the tiring pin 46 so las to enable the tiring pin to strike the cap on the head ofthe cartridge v C when the tiring pin is released. The liring pin 46 is slidably mounted `in a stationary Wall 47 in the handle portion it) and is moved by the force of -a compression spring 48. A sear plate 49 i-s slidable up and down to a limited extent on the breech block 32.

The tiring pin i6 has a reduced diameter portion at its forward end forming a `shoulder on the firing pin. The Sear plate 49 (see also FGURES 7 and 8) has an aperture 49A, the diameter of which corresponds -to the tiring pin diameter behind the shoulder, and this sear plate also has a slot 49B extending above the aperture 49A the width of which slot corresponds to fthe smaller tiring pin diameter ahead of the shoulder. When the sear plate is in the normal low position of FIGURES 1 and 7 it holds the tiring pin back from engagement with the cartridge, but when raised to the firing position -of FIGURES 6 and 8, the sear plate releases the firing pin. A spring 50 holds the saar plate normally in the low, iiring-pin-engaging position. A trigger 51 (FIGURES l, Zand 6) is so positioned as yto enable the sear plate 49 tto be raised when vthe breech block 32 occupies the rear position of FG- URES 2 and 6.

In order to prevent any inadvertent actuation of the 'trigger 5l, even when the members of the device are in tiring position, la trigger `safety locking lever S2 is provided (FIGURES 2, 6, 9, l0 and 13) which is pivotally mounted in `an outside recess in the housing portion 10 and which has an outwardly extending linger push knob 53 (FGU'RES 9 and 13) at its forward end. The opposite or rear end of the -lever 52 entends inwardly into the device sufficiently to rest on the top of the trigger, as shown in FiGURES 1 and 2,fand prevents actuation of the Itrigger when in such position. The lever 52 is pivotally mounted on the pin 52 (FGURE 9) and a spring, indicated at 53', holds the lever 52 in its normal position (shown in full lines in FIGURE 9), in engagement with the trigger but permits the lever to be moved Vout of trigger-engaging position to the position shown in dotted lines in FIG. 9 by linger pres-sure on the knob 53. Thus,

in order to tire the device not only must `the muzzle of thegun barrel be pressed against the work and the device held thrust against the work, but the knob 53 must also be pressed inwardly before the trigger can be pulled. Due to the location of the knob 53, Iboth hands of the operator are Irequired to be used in order to tire the device. Consequently any inadvertent tiring of the device is quite impossible.

The inner portion of the gun Ibarrel 13 is formed with a longitudinally-extending groove 54 (FIGURES -'1 and 2) on its outside wall. Ports 55 and 56 at the ends of this groove respectively connect with the gun barrel chailnel. The groove 54 is formed into a separate channel by the encompassing walls of the sleeve 2'7 and barrel block 26. Thus the resul-ting ychannel groove 54, due to its connection at each end with the main gun barrel channel, constitutes an auxiliary bore or gas escape passage. An adjustable screw 57, controlling passage through the port S5, is capable of allowing `some of the discharge gas from the discharging cartridge C to pass through this auxiliary bore, `and consequently the adjusting of this screw 57 regulates the `amount of discharge gas which will pass through the auxiliary bore. The screw 57 can, of course, close ofi the auxiliary bore entirely.

The head 58 of this adjustment screw 57 (FIGURES 7 l, 2 and 6) is located in a recess 59 in the bottom of the barrel block 26 (see also FIGURE ll) and is accessible for adjustment when the device is in fully opened position. Preferably the head SS of the adjusting screw and the cavity wall are provided with some indicia markings so that the screw 57 can be set for a predetermined accurate adjustment and in this way provide for accurate control of the passage of gas through the port 55 and thus through the auxiliary bore.

As will be evident from FIGURES 1 and 2, `the purpose of this auxiliary bore or gas escape passage S4 is to enable a portion of the explosive gases, Ydischarged upon the tiring of the cartridge C, to pass through the auxiliary bore, `when desired, in order to reduce the amount of driving force exerted upon the projectile by the discharged gases released from the fired cartridge. By bleeding off some of the discharged gases behind the tired projectile and delivering them subsequently back into the main bore of the gun barrel (which gases will be delivered back into the gun barrel bore in advance of the projectile due to the inertia in the projectile, when first acted upon by the explosive gases) the force with which the projectile is driven into the work can be modified. This is an important feature since it enables identical explosively driven projectiles to be used on different densities of material without having the projectile driven too far into the work surface if the density of the work happens to be less than that for which such explosively driven projectile was originally intended.

Preparatory to operating the device the handle portion 10 and the portion 11 of the housing are pulled a maximum distance apart into the relative position shown in FIGURE l2. The handle portion 10 is then swung downwardly to the position illustrated in FIGURE 13 causing any previously tired cartridge to be ejected, and, as the handle portion I10 swings down slightly further, the ejector plate 40 returns to normal position, enabling a cartridge and projectile to be placed in the breech end of the gun barrel. The handle portion 10 is then moved back into normal position and the handle portion 10 and portion l1 of the housing are allowed to come together. The device will now be in the normal position illustrated in FIGURE l and loaded for tiring.

In the tiring operation the muzzle end of the gun barrel is placed against the surface into which the projectile is to be discharged and the handle portion 10, and with it the housing portion 11, are thrust forwardly on the gun barrel against the force ofthe springs 64 and 31, and also against the force of the springs 20 and 23 which bear against the plates 18 and 21 respectively. The Sear plate 49 holds the firing pin 46 against forward movement so that the firing pin spring is also compressed. This brings the device into the position illustrated in FIGURE 2 in which the lower portion of the sear plate is above the trigger 51. While the device is held in this position, the operator presses the knob 53 (FIGURE 9) inwardly to release the trigger locking lever 52, and then presses the trigger 5i. The pressing of the freed trigger raises the sear plate 49 (FIGURE 4) and releases the tiring pin 46, causing the tiring pin, under the impetus provided by the spring 48, to strike the head of the cartridge and cause the ex plosively-driven projectile to be discharged.

Occasionally it may be desired to drive the projectile or fastening element into the work at some point which is recessed from the remaining work surface. If the muzzle end of the gun barrel were held spaced from the bottom of each recess it would then be spaced from the actual surface to be pierced by the projectile. This would prevent the firing of our improved device, but even if ring were possible with the gun muzzle end spaced from the surface to be pierced the results would not be satisfactory. Therefore, we have made provision so that the gun barrel muzzle in such case may extend for considerable distance beyond the protective pads 24 and 25 and the housing 17.

The inner end of the housing portion or sleeve 12 has a rim tlange 62 which is normally engaged by the springcontrolled locking lever 63 when the device is set for firing. However, release of the locking lever 63, which is done by pressing the opposite end of the lever against the force of spring 65, enables the rest of the housing assembly, together with the gun barrel, to be thrust forwardly against the force of spring 64 to some such position as illustrated in FIGURE l7. In this position this muzzle end of the gun barrel will extend a considerable distance beyond the protective pads 24 and 25.

Thus, by releasing the locking lever 63, the muzzle tip of the gun barrel can be caused to engage the inner wall of a recess in the work while at the same time the protection pads Z4 and 25 are held by spring force against the main surface of the work around such recess and will continue to perform that function of protecting the operator and bystanders against any fragments which may be dislodged by the impact of the projectile or discharged gases.

Several minor modifications would be possible in our improvedv device without departing from the principle and scope of our invention. The device in the form as described and illustrated has been found to be very satisfactory in practice and we regard this as the preferred construction, but it is not our intention to limit our invention otherwise than as set forth in the claims.

We claim:

l. In a stud driving tool, a rear handle portion including a breech block comprising a yoke member having spaced apart yoke sections extending forwardly from said handle portion, a front barrel containing portion including a barrel block positioned between said yoke sections, a barrel mounted in and extending through said barrel block and between said yoke sections, a pivot pin connecting said yoke sections and said barrel block to provide for pivotal movement of said portions to expose the breech end of said barrel and interlock means normally preventing relative pivoting movement between said portions, parts of said portions being connected to have relative sliding movement in a direction longitudinally of said barrel away from each other, resilient means urging said parts toward each other `to engage said interlock means, said interlock means being released by relative movement of said parts away from each other.

2. In an explosively actuated tool including a handle portion and a barrel containing portion, a breech block carried by said handle portion, a gun barrel carried by said barrel containing portion, a connection between said portions providing for relative pivotal movement of said portions about an axis transverse to the axis of said barrel to expose the breech end of said barrel, locking means preventing said relative pivotal movement, said handle portion being slidable relative to said barrel containing portion in a direction longitudinally of said barrel, resilient means urging said handle portion toward said barrel containing portion to engage said locking means, said locking means being releasable by movement of said handle portion away from a portion of said barrel containing portion.

3. In an explosively actuated tool, a housing assembly including a handle portion, an intermediate portion and a forward end portion, a gun barrel in said intermediate portion and forward end portion of said housing assembly, said housing assembly being mounted for limited slidable movement with respect to said gun barrel and said handle portion and intermediate portion being relatively movable in a direction longitudinally of said barrel away from each other, the breech end of said gun barrel adapted to receive a cartridge, a barrel block secured on the breech end of said gun barrel and located in said intermediate portion of said housing assembly, a breech block adjacent said barrel block and located in said handle portion of said housing assembly, said handle portion being slidable to a limited extent on said breech block, said breech block bcing hingedly connected with said barrel block, whereby said handle portion with said `breech block may be swung to open position lwith respect to said barrel block and intermediate portion of said housing assembly, resilient means urging said handle portion and intermediate portion toward each other, and a hinge flock engageable by relative movement of said handle portion and intermediate portion toward each other for preventing said handle portion from being swung to open position, said hinge lock being releasable by relative movement of said handle portion and said intermediate portion in a direction away from each other.

4. In a device for driving projectile fastening elements into a `solid work surface, a housing assembly comprising a handle portion, an intermediate portion and a forward end portion, a gun barrel in said intermediate portion and forward end portion of said housing assembly, said hou-sing assembly being mounted for limited slidable movement with respect to said gun barrel and said handle portion and intermediate portion being relatively movable in a direction longitudinally of said barrel away from each other, spring means holding said housing assembly in normal position with respect to said gun barrel and urging said handle portion and intermediate portion toward each other, the breech end of said gun barrel adapted to receive 'a cartridge, a barrel block secured on the breech end of said gun barrel and located in said intermediate portion of said housing assembly, a breech block adjacent said barrel block and located in said handle portion of said housing assembly, said handle portion being slidable to -a limited extent on said breech block, said breech block -being hingedly connected with said barrel block whereby said handle portion with said breech block may be swung to open position with respect to said barrel block and intermediate portion of said housing assembly to expose the breech end of said barrel, and a hinge lock preventing said handle portion from being swung to open position, said hinge lock being e11- gageable by relative movement of said handle portion and said intermediate portion toward each other and releasable by relative movement of said handle portion and I'said intermediate portion in a `direction away from each other.

5. In a stud driving tool a rear handle portion including a breech block comprising ya yoke member having spaced apart yoke sections extending forwardly from said handle portion, a front portion containing a barrel and including a barrel block positioned between said yoke sections, a pivot pin connecting said yoke sections and said barrel block to provide for pivotal movemen-t ot" said portions to expose the breech end of said barrel and interlock means normally preventing relative pivoting movement between said portions, parts of said portions being connected to have relative sliding movement in a direction longitudinally of each barrel away from each other, resilient means urging said parts toward each other to engage said interlock means and said interlock means being released by relative movement of said parts away from each other.

6. |In an explosively actuated tool including -a handle portion and a barrel portion, :a breech block carried by said handle portion, a gun barrel carried 4by said barrel portion and having a breech end normally closed by said breech block, a connection between said portions providing for movement of said breech end of said barrel in a direction laterally of said breech block to expo-se the breech end of said barrel, interlock means normally preventing said movement, parts of said handle and barrel portions having relative sliding movement in a direction longitudinally of said barrel away from each other, resilient means urging said handle and barrel portions to ward each other to engage said interlock means and said interlock means being released by said relative movement of said parts away from each other.

7. An explosively actuated stud driving tool comprising a front portion including a barrel block and a barrel having Ii-ts rear end extending through said barrel block, and a rear portion including a handle pant land a breech block in the form of an integral yoke member having yoke portions extending forwardly and embracing said barrel block, the axis of said barrel and said end of said barrel extending .between said yoke portions, a pivot pin connecting said breech block to said barrel block for relative pivotal movement of lsaid portions between a closed position and an open position of said portions, said rear portion having a part thereof in alignment with the longitudinal axis of said barrel when said portions are in said `closed position relative to each other, said pivot pin being spaced laterally from said longitudinal axis and extending perpendicularly to said longitudinal axis, said front portion also including a barrel housing assembly slidably mounted on said barrel vfor movement longitudin-ally of said barrel,-a Spring positioned between said housing assembly and said barrel to urge said housing assembly toward said rear portion of said to-ol with respect to said barrel, a locking element carried by said housing assembly and interengagingwith said rear portion to lock said rear portion to said front portion against said pivotal movement when said front and rear portions are in said Iclosed position relative to each other, said locking element being relea'sable from said rear portion upon sliding movement of said housing assembly longitudinally on said barrel to compress said spring to thereby enable pivotal movement of said front and rear portions relative to each other to said open position.

References Cited in the le of this patent UNITED STATES PATENTS 239,662 Martin Apr. 5, 1881 258,923 Hollenbeck June 6, 1882 530,467 Balensiefer Dec. 4, 1894 1,365,869 Temple Jan. 18, 1921 2,645,772 Walker July 21, 1953 2,775,762 Hilti Jan, 1, 1957 2,799,108 Kopf et :al July 16, 1957 2,804,620 Gannon Sept. 3, 1957y 2,835,894 Behrend May 27, 1958 2,945,236 Kopf et a1 July 19, 1960 FOREIGN PATENTS 506,769 Belgium Nov. 14, 1951 521,711 Belgium Aug. 14, 1953 306,918 Great Britain Feb. 28, 1929 772,351 Great Britain Apr. 10, 1957 (Corresponding to 521,711) Y 1,093,416 France Nov. 17, 1954 France June 18, 1956

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