US3776443A - Fastener driving tool with slidable fastener guide - Google Patents

Abstract

An explosive fastener driving tool has an adapter mounted on the muzzle end of the barrel and slidably holds a gas actuated liner for receiving a ram. The liner bears on the washer portion of a fastener while the ram impacts the fastener head to insure that the fastener piercing point is guided for efficient work penetration.

Description

United States Patent [1 91 Oefinger 1 Dec. 4, 1973 FASTENER DRIVING TOOL WITH SLIDABLE FASTENER GUIDE [75] Inventor: Richard W. Oefinger, Shelton,

Conn.

[73] Assignee: USM Corporation, Boston, Mass.

[22] Filed: May 23, 1972 [21] Appl. No.: 256,086

[52] US. Cl. 227/10 [51] Int. Cl. B25c 1/14 [58] Field of Search 227/8, 9, 10, ll

[56] References Cited UNITED STATES PATENTS 2,930,042 3/1960 Temple et al 227/l0 3,348,751 lO/l967 Henning ..227/8 Primary Examiner-Granville Y. Custer, Jr. Attorney-Carl E. Johnson et a].

[57] ABSTRACT 5 Claims, 5 Drawing Figures FASTENER DRIVING TOOL WITH SLIDABLE FASTENER GUIDE BACKGROUND OF THE INVENTION Explosive fastener driving tools commonly comprise a housing for a barrel, a firing mechanism and means for energizing the mechanism whereby a cartridge or other charge in the breech end of the barrel may be ignited and the resultant gas directed into the barrel to axially drive a ram for impacting a fastener. The latter ordinarily has a pointed end and a head end, the head end being struck by the ram to drive the pointed end into a solid material such as concrete or steel.

The driving forces produced are not always uniform, and neither is the resistance to penetration which may be provided by a structure. Aside from the fact that fasteners of different size and shape are employed, the hardness of different fastener receiving structures vary, and the efficiency of explosive driving tools is inconstant. One approach to accommodating different fastener sizes has been to provide a suitable adapter or guide at the muzzle end of the barrel for directing the ram against each fastener head. Also, to enable the tool and a particular fastener to adjust to the varying driving and reactive forces, a washer is often frictionally slidable on the fastener stem.

It is found that in the known tools the driving of washer-carrying fasteners from an adapter by a ram is not reliably effective since penetration resistance offered by a hard receiving structure may cause the fastener to bend or break. Moreover, this fastener deformation usually occurs oftener when shorter fasteners are used since they tend more easily to become cocked, i.e., tilted from coaxial relation with the ram.

SUMMARY OF THE INVENTION In view of the foregoing it is a primary object of this invention to provide, in an explosive fastener driving tool of the type having a barrel with a telescoping ram, and a tubular adapter coaxially mounted on the barrel for receiving a fastener to be driven by the ram, an improved means slidable within the adapter for axially guiding the fastener to insure its effective penetration into hard structure.

Another object of this invention is the provision, in a tool'of the type aforesaid, of a guide means telescoped between the adapter and the ram and arranged to be concurrently driven therewith by the high velocity gases in the barrel bore, the guide means bearing axially on a washer on the fastener stem as the ram impacts a head of the fastener peripherally supported in the guide means-whereby the fastener is stabilized during penetration of hard material.

To these ends, and as herein shown, a feature of the invention resides in the combination with a barrel having a bore for axially mounting on the barrel for receiv-' -ingly accommodating the ram and the fastener head,

one end of the liner being subjected to the pressure of the explosive gases bypassing the ram and the other end of the liner engaging the washer to stabilize the fastener during driving.

BRIEF DESCRIPTION OF THE DRAWINGS The foregoing and other features of the invention will now be more particularly described in connection with an illustrative embodiment, and with reference to the accompanying drawings thereof, in which:

FIG. 1 is a view in side elevation of an explosive fastener driving tool in uncocked condition, a muzzle end portion being shown in axial section to reveal an adapter liner;

FIG. 2 is an enlarged view in axial section of the muzzle portion shown in FIG. 1, a fastener and driving parts now being in ready-to-fire condition;

FIG. 3 is a sectional view showing a conventional adapter and a fastener improperly driven due to lack of adequate guidance thereby;

FIG. 4 is a view similar to FIG. 2, the parts now being in driven position and the result contrasting with that shown in FIG. 3, and

FIG. 5 is a transverse section taken on the line VV of FIG. 2 and indicating the slidable mounting connection of the muzzle adapter to its liner.

DESCRIPTION OF PREFERRED EMBODIMENT An explosive fastener driving tool generally designated 10 in FIG. 1 comprises a housing 12 having an open side 14 for providing access to load the breech bore of an axially slidable barrel 16. It will be understood that a firing mechanism not shown is mounted within a handle portion 18 secured to the housing and having a trigger 20. Preferably the tool has its firing mechanism cocked by thrusting the housing 12 relatively muzzleward on the barrel and forcing an adapter 22 (FIGS. 1, 2, and 4) endwise against a work piece P to be secured to a surface S, for instance of solid steel, wherein a fastener F is to be driven.

Actuation of the trigger 20 effects explosion of a suitable charge (not shown) whereby a piston-type ram 24 coaxially slidable in the barrel 16 is caused by the explosive gases therein to drive the fastener F through the work piece and into the structure S.

The fastener Fmay have a head at one end to be impacted by the ram 24 and a pointed end for penetrating the structure. Also the fastener may, though not necessarily, be of the type including a washer W frictionally slidable axially on the fastener stem as it penetrates the work to prevent overdrive. The washer customarily has a larger diameter than the fastener head and is concentric therewith.

As illustrated in FIG. 3 the conventional type of muzzle adapter shown at 26 allows the washer W and the fastener to be tilted from the driving axis on eccentrically engaging the work piece and meeting resistance to work piece penetration. Hence the fastener becomes bent in fishhook manner and may break. The result is that the fastener is not fully driven and a relatively lower holding power of uncertain degree is obtained.

The present invention advantageously provides for the adapter 22 to have a coaxial guide or liner 28 of shorter length as will next be described. The adapter 22 is herein shown as having retention in the barrel by means of an O-ring 30 seated in mating circumferential grooves, and a retaining ring 32. As a precautionary measure a flat spring clip 34 may have inturned diametric end portions 36 in latching relation with a shoulder of the barrel. The adapter 22 has a generally uniform bore 38 coaxial with the ram 24 and an enlarged, slightly tapered mouth portion for frictionally accommodating the washer W. Coaxially telescoped between the adapter 22 and the ram 24 is the liner 28 having an enlarged muzzle end 40 for bearing on the washer W, a head end 42 in which an end of the ram 24 is initially received, and a flat side portion 44 for slidably receiving a spring pin 46 partly nested in a transverse bore formed in the adapter 22 as shown in FIG. 5. In an alternate design (not shown) the liner 28 may be of uniform diameter except for an enlarged head at the barrel bore end.

Referring to FIG. 2, the tool is now cocked and, as in the uncocked condition shown in FIG. 1, the liner 28 retains the fastener coaxially aligned, its head being guided in the smooth bore of the liner 28 and the washer W, if employed, being engaged by the liner muzzle end 40. This fastener supporting and guiding relation is maintained during driving. Following ignition of the charge the gas of combustion propels the ram 24 axially to impact the fastener head, and it is believed that a portion of the gas escapes at high velocity around the ram to advance in the barrel bore for reaction against a rear face of the liner head end 42. While the velocity relationship of the liner and the ram is unknown, it is believed that the liner 28 is axially driven at about the same time as the ram. As a consequence, the liner muzzle end 40 thrusts the washer W toward the work piece while the liner bore axially guides the fastener head as it is driven by the ram. The fastener F is thus preventing from wobbling and engaging the work piece P eccentrically. Accordingly, the fastener pointed end will, despite stiff resistance, penetrate the work piece and structure S with good efficiency and no distortion or breakage. A five-eighths inch length fastener, for instance, is thus enabled to be driven to full penetration in solid steel without requiring extra power in a charge such as would be required were the fastener to become askew as shown in FIG. 3.

While the fastener guiding influence of the washer W is usually preferred, it will be understood that the adapter line 28 is advantageous in the guiding and driving of the headed and threaded fastener having no washer. The bore of the liner as it is driven axially maintains the fastener head aligned so that the fastener stem is kept substantially normal to the work piece during driving.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. An explosive fastener driving too] comprising a barrel having a bore for axially guiding a fastener driving ram, an adapter mounted on the muzzle end of the barrel for receiving a fastener to be driven by the ram, and a tubular liner disposed for coaxial telescoping movement between the ram and the adapter, the bore of the liner being adapted to slidably support and guide at least one peripheral portion of the fastener as it is driven into a structure.

2. An explosive tool for driving washer-carrying headed fasteners comprising a barrel, a muzzle adapter mounted on the barrel for receiving a fastener to be driven, a ram axially slidable in the barrel bore for impacting the head of the fastener, and a liner axially slidable in the adapter while telescopingly accommodating a portion of the ram and the head of the fastener, an end of the liner being adapted to bear on the washer endwise to stabilize the fastener during driving.

3. A tool as in claim 2 wherein a head end of the liner remote from a fastener to be driven occupies the space between the adapter and the ram for reaction to explosive gases bypassing the ram.

4. A tool as in claim 2 wherein means interconnects the adapter and the liner to permit them relative, limited longitudinal movement.

5. A tool as in claim 4 wherein said means comprises a longitudinal flat portion on the liner and a transverse pin mounted in the adapter partly extendsfor relative movement along the flat portion.

Claims (5)

1. An explosive fastener driving tool comprising a barrel having a bore for axially guiding a fastener driving ram, an adapter mounted on the muzzle end of the barrel for receiving a fastener to be driven by the ram, and a tubular liner disposed for coaxial telescoping movement between the ram and the adapter, the bore of the liner being adapted to slidably support and guide at least one peripheral portion of the fastener as it is driven into a structure.

2. An explosive tool for driving washer-carrying headed fasteners comprising a barrel, a muzzle adapter mounted on the barrel for receiving a fastener to be driven, a ram axially slidable in the barrel bore for impacting the head of the fastener, and a liner axially slidable in the adapter while telescopingly accommodating a portion of the ram and the head of the fastener, an end of the liner being adapted to bear on the washer endwise to stabilize the fastener during driving.

3. A tool as in claim 2 wherein a head end of the liner remote from a fastener to be driven occupies the space between the adapter and the ram for reaction to explosive gases bypassing the ram.

4. A tool as in claim 2 wherein means interconnects the adapter and the liner to permit them relative, limited longitudinal movement.

5. A tool as in claim 4 wherein said means comprises a longitudinal flat portion on the liner and a transverse pin mounted in the adapter partly extends for relative movement along the flat portion.

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