Explosive Actuated Extendable Driving Tool

1. Field of Invention

The present invention relates to explosive actuated tools and, more particularly, is directed towards explosive actuated tools for driving fastening elements into work surfaces such as ceilings, walls and the like.

2. Description of the Prior Art

A variety of explosive actuated tools for driving fastening elements have been developed over the years. Such tools include those shown in U.S. Pat. Nos. 3,665,583; 3,407,982; 3,797,721; 3,805,472; 4,655,380 and the patents cited therein. Prior art explosive actuated driving tools suffer from several disadvantages and limitations. Generally, explosive actuated driving tools are relatively complex in construction and costly to manufacture. In addition, due to inadequate venting of the combustion chamber, many of these tools suffer from the disadvantages that they are relatively noisy and they tend to jam from a buildup of spent powder. Typically, pole assembly driving tools are not readily adaptable to receive extendable members for increasing the length of the pole assembly Furthermore, pistol type explosive actuated driving tools are not easily adapted to be mounted to a pole assembly for driving fastening elements into ceilings.

It is an object of the present invention to provide an explosive actuated driving tool which does not suffer from the heretofore mentioned disadvantages and limitations.

Another object of the present invention is to provide an explosive actuated extendable tool for driving a fastening element into a work surface such as a ceiling, wall or the like.

Yet another object of the invention is to provide an explosive actuated driving tool having an extendable handle which operates as a slidable ram for firing an explosive charge.

A further object of the invention is to provide an explosive actuated tool which permits precise positioning of the fastening element against the work surface into which the fastening element is to be driven by an exploding charge.

Yet a further object of the present invention is to provide an explosive actuated driving tool with a self-aligning muzzle and noise suppression element.

An explosive actuated extendable driving tool embodying the invention has a housing with a barrel connected to a front end of the housing for receiving a fastening element that is to be secured in a work surface such as a ceiling, wall or the like. A manually actuated reciprocatable positioner shaft is slidably received in a retainer that is mounted to a back end of the housing, the positioner shaft being biased by a spring towards a back end of the diving tool. An extendable handle is connected to the back end of the positioner shaft. A muzzle with a self-aligning spall guard and a splash guard is mounted to a front end of the barrel, the spall guard being constrained for limited movement relative to the barrel. The splash guard, which is disposed about the spall guard, is constrained for limited movement relative to the spall guard. A noise suppression element is contained in a compartment that is formed between the spall guard and the splash guard. A penetrating tip of the fastening element extends outwardly from the front end of the spall guard, a back or firing end of the fastening element is in contact with an explosive charge that is placed in a load chamber formed in an inner end of the barrel. A washer with a central opening is received and held in a socket formed in a front end of the spall guard, the penetrating tip of the fastening element projecting through the washer opening. Discharge ports formed in the barrel and spall guard define exits for the discharge of combustion gases and carbon into the noise suppression element When the handle is pushed inwardly towards the front or muzzle end of the driving tool, the positioner shaft is urged into contact with the housing. In consequence, the penetrating tip of the fastening element presses against the work surface and the firing end of the fastening element is forced against the explosive charge with sufficient force to set off the charge and drive the fastening element into the work surface, the washer being held against the work surface by the fastener.

The invention accordingly comprises the apparatuses and systems, together with their parts, elements and interrelationships that are exemplified in the following disclosure, the scope of which will be indicated in the appended claims.

A fuller understanding of the nature and objects of the present invention will become apparent upon consideration of the following detailed description taken in connection with the accompanying drawings, wherein:

FIG. 1 is a side view of an explosive actuated driving tool embodying the present invention;

FIG. 2 is an end view of the muzzle of the driving tool shown in FIG. 1; and

FIG. 3 is a side view in cross-section of the driving tool shown in FIG. 1.

Referring now to the drawings, particularly FIG. 1, there is shown an explosive actuated extendable driving tool 10 embodying the present invention. Driving tool 10 comprises a housing 12 having a muzzle 14 at a discharge or front end 16 of the tool and a trigger assembly 18 at a back end 20 of the tool.

As best shown in FIG. 3, housing 12 includes a barrel 22 at front end 16. Barrel 22 is formed with a central bore 24 and a load chamber 26. Bore 24 is configured to receive a fastening element 28 that is to be secured to a work surface (not shown), for example, a ceiling, a wall or the like. Load or explosion chamber 26 is configured to receive a percussion explodable charge 30 which is ignited by the trigger assembly 18.

Trigger assembly 18 includes a retainer 32 that is mounted to housing 10 and a positioner shaft 34 which is slidably received in the retainer. A nipple 36 is attached to positioner shaft 34 and a handle 38 is connected to the nipple As hereinafter described, handle 38 is pushed inwardly to ignite charge 30 and propel fastening element 28 out of barrel 22 and muzzle 14 and into the work surface.

Muzzle 14 includes a self-aligning spall guard 40 and a splash guard 42. Spall guard 40 is mounted to a front end of barrel 22, the spall guard being constrained for limited movement relative to the barrel. Splash guard 42, which is disposed about spall guard 40, is constrained for limited movement relative to the spall guard. A noise suppression element 44 is contained in a chamber 45 that is formed between the spall guard 40 and the splash guard 42. Preferably, but not necessarily, noise suppression element 44 consists of metal wire mesh. Discharge ports 46 and 48 formed in barrel 22 and spall guard 40, respectively, define exits for the discharge of combustion gases into noise suppression element 44.

Splash guard 42, which captures fragments from the work surface into which the fastening element 28 is to be driven, for example, a concrete ceiling, is a hollow member having a substantially fustro-conical internal chamber 50 with a wide mouth 51 at its front end and a tubular section 52 at its back end. An internal annular rib or flange 54 is formed at a forward end of tubular section 52, the rib being biased against a rear shoulder 56 of spall guard 40 by a compression spring 58.

Spall guard 40 has a substantially mushroom profile in right cross-section with an enlarged head 60 and a fustro-conical body 62 Spall guard 40 has a central bore 64 with an enlarged socket 66 at its front end. Socket 66 is configured to receive a washer 68 with a central opening 70. A plurality of magnet and sleeve assemblies 72 (FIG. 3) are fitted into holes 74 that are drilled into spall guard 40. Magnet and sleeve assemblies 72 releasably hold washer 68 in socket 66. The tip of fastening element 28 projects through opening 70 when the fastening element is loaded into barrel 22. A plurality of grooves 76 that are formed in the front end of spall guard 40 are configured to receive tongue members 78 that are formed at the front end of barrel 22. The tongue and groove arrangement permits limited longitudinal movement of spall guard 40 relative to barrel 22 while constraining the spall guard against rotational movement relative to the barrel. The play between spall guard 40 and barrel 22 compensates for any uneveness in the work surfaces that the spall guard is pressed against and allows for escape of carbon from the ignition of charge 30 in load chamber 26.

As previously indicated, barrel 22 is formed with central bore 26 and a load chamber 26. A spring housing 79 in the form of a cylindrical sleeve 81 with a shoulder 83 at a back end is slidably fitted over barrel 22. Spring 58 is captively held against lateral movement by barrel 22 and spring housing 79, the ends of spring 58 being in contact with rib 54 and shoulder 83. An ejector tube 80 is slid onto barrel 22, a front end of the ejector tube being in contact with the back end of shoulder 83. Ejector tube 78 is formed with opposed longitudinally extending slide slots 82 and opposed transverse lock slots 84.

A tubular hand grip 86 is slidably received on ejector tube 80. A roll pin 88 is press fitted into opposed holes 90 in hand grip 86, the roll pin passing through transverse lock slots 84. When hand grip 86 is rotated to an unlocked position, roll pin 88 is aligned with longitudinally extending slide slots 82, and the hand grip is free to move longitudinally. When roll pin 88 is positioned in lock slots 84 and out of alignment slide slots 82, hand grip 86 is in its locked position and the hand grip is constrained against longitudinal movement. When hand grip 86 is moved longitudinally, it carries with it an ejector 92 which is slidably received in barrel 22.

Ejector 92 has a narrow front end 94 and an enlarged head 96 at a back end Ejector 92 is constrained for movement between a stored position and an ejecting position for ejecting a spent charge from barrel 22. A compression spring 98 bears against a shoulder 100 in barrel 22 and a torsion spring housing 102. In an alternate embodiment, transverse lock slots 84 are eliminated and compression spring 98 is sufficiently strong that ejector 92 moves longitudinally with longitudinal movement of hand grip 86. A torsion spring roller 104 is attached to torsion spring housing 102. A torsion spring 106 is held between torsion spring housing 102 and ejector head 96.

A positioner housing 108 is attached, for example by threads, to a back end of ejector tube 80. Retainer 32 is attached to a back end of positioner housing 108 by threads, for example. Positioner housing 108 has a bore 110 that is configured to receive positioner shaft 34. Positioner shaft 34 has an elongated narrow body 112 and an enlarged head 114 that is internally threaded for interconnecting with nipple 36. A compression spring 116 is constrained between a shoulder 118 of positioner housing 108 and enlarged head 114. A coupling 120 is turned onto a threaded back end of nipple 36 and a front threaded end of a nipple 122 is turned into coupling 120. Handle 38 is attached to nipple 122. Although two connected nipples 36 and 122 are shown, it is to be understood that in other embodiments the number of nipples is other than two, for example one or three or four or some other number. The number of nipples is determined by the desired length of tool 10.

In operation of driving tool 10, a charge 30 is positioned in load chamber 26. Next, a fastening element 28 is placed in bore 24, the fastening element having a ridged head 124 that rests against charge 30. The tip of fastening element 28 projects outwardly of bore 24. Washer 68 is placed over the projecting tip of fastening element 28, the washer being held in socket 66 by magnet and sleeve assemblies 72. Next, spall guard 40 and splash guard 42 are placed against a work surface into which fastening element is to be driven, tool 10 being pushed against the work surface by nipple 36 or handle 38. Next, handle 38 is rapidly pushed toward muzzle 14. This rapid movement of handle 38 causes positioner shaft 34 to strike positioner housing 108. Positioner housing 108, ejector tube 80, spring housing 79, spall guard 40 and splash guard 42 are interconnected in such a manner as to provide a rigid structure. The force exerted by handle 38 on positioner housing 108 via positioner shaft 34 is transmitted to spall guard 40, which in turn is forced backward by fastening element 28 and washer 68. The backward movement of fastening element 28 drives ridged head 124 of the fastening element into the charge 30. The charge is ignited and fastening element 28 is fired into the work surface, washer 68 being pressed against the work surface. Discharge gases resulting from the firing of charge 30 escape through ports 46 and 48 into noise suppression element 44.

Since certain changes may be made in the foregoing disclosure without departing from the scope of the invention herein involved, it is intended that all matter contained in the above description and depicted in the accompanying drawings be construed in an illustrative and not in a limiting sense.