US3918621A

US3918621A - Explosive charge-driven anchoring element setting gun

Info

Publication number: US3918621A
Application number: US483717A
Authority: US
Inventors: Peter Jochum; Gottfried Benz
Original assignee: Hilti AG
Current assignee: Hilti AG
Priority date: 1973-07-03
Filing date: 1974-06-27
Publication date: 1975-11-11
Anticipated expiration: 1992-11-11
Also published as: DE2333887C2; DE2333887A1

Abstract

In a setting gun using an explosive charge for driving anchoring elements into a solid receiving material, a barrel is provided which is axially displaceable within the gun housing. The rearward end of the barrel is positioned adjacent a member which forms the cartridge chamber. A shoulder is formed on the rearward end of the barrel facing toward the cartridge chamber and the explosive gases developed when a cartridge is fired, are directed against the shoulder providing a propulsive force displacing the barrel toward the forward end of the gun housing.

Description

United States Patent [191 Jochum et al.

[4 1 Nov. 11,1975

1 1 EXPLOSIVE CHARGE-DRIVEN ANCHORING ELEMENT SETTING GUN [75] Inventors: Peter Jochum, Meiningen, Austria;

Gottfried Benz, Nendeln,

Liechtenstein [73] Assignee: Hilti Aktiengesellschaft,

Liechtenstein [22] Filed: June 27, 1974- 21 App]. No.: 483,717

[30] Foreign Application Priority Data July 3, 1973 Germany .Q 2333887 [52] U.S. Cl. 227/10 [51] Int. Cl. B25C 1/14 [58] Field of Search 227/8, 9, 10, ll

[56] References Cited UNITED STATES PATENTS 12/1960 Schulz 227/8 3,075,197 l/1963 Kissane .227/8 3,481,143 12/1969 Hsu .237/1UX Primary Eraminer-Granville 1. Custer, Jr. Attornar, Agent, or FirnzToren, McGeady and Stanger 5 7 ABSTRACT In a setting gun using an explosive charge for driving anchoring elements into a solid receiving material, a barrel is provided which is axially displaceable within the gun housing. The rearward end of the barrel is p0- sitioned adjacent a member which forms the cartridge chamber. A shoulder is formed on the rearward end of the barrel facing toward the cartridge chamber and the explosive gases developed when a cartridge is fired, are directed against the shoulder providing a propulsive force displacing the barrel toward the forward end of the gun housing.

10 Claims, 2 Drawing Figures 1 atem Nov. 11, 1975 FIG. 2

EXPLOSIVE CHARGE-DRIVEN ANCHORING ELEMENT SETTING GUN SUMMARY OF THE INVENTION The present invention concerns a setting gun using an explosive charge for driving anchoring elements into a solid receiving material and, more particularly, it is directed to a barrel which is axially displaceable within the gun and can be driven forwardly by the explosive gases developed when acartridge is-fired.

These are known setting guns in which the barrel is axially displaceable within the gun housing; When the gun is is use, the forward end of the barrel is .placed in contact with the receiving material, that is, the material into which the anchoring element is driven. For safety reasons, that is, to prevent accidental discharge of the anchoring elements, such setting guns are designed so that the cartridge is not in position to be ignited by the firing pin until the barrel is pressed against the receiving material and is displaced rearwardly within the gun housing. Only when the gun is pressed against the receiving material and the barrel rides rearwardly through the housing, is the cartridge moved into position for ignition. Normally, the displacement of the barrel within the gun is effected against the action of a spring positioned between the barrel and the housing, so that the cartridge is held out of the range of the firing pin when the barrel is not pressed with sufficient force against the receiving material. Accordingly, the force with which the barrel of the gun must be pressed against the receiving material is that amount necessary to overcome the force of the spring biased against the rearward end of the barrel, or appropriately, the force acting on the barrel must be only slightly greater than the spring force for positioning the gun so that a cartridge can be fired. However, for technical reasons, the force of the spring must not be too high, since it would make handling the gun more difficult and increase the risk of accidents in places where access is difficult to achieve, particularly when working on a ladder. Accordingly, it is customary to select the spring tension at about kp.

It has been found, however, that the relatively low pressing force required to overcome the spring force, is not always sufficient to press objects to be fastened, for example, metal plates, tightly against the receiving material. In such conventional guns, a cartridge is fired and the anchoring element propelled into the receiving material, there may still be a cavity between the member to be fastened and the receiving material. Usually such cavities are invisible to the person operating the setting gun, especially when metal sheets are being fastened. If the anchoring element is driven against a loosely held member, the head of the anchoring element pierces the member and effective attachment to the receiving material will not be achieved. This characteristic is particularly critical when stacked sheets are being attached to the receiving material.

Due to thereaction forces produced when a cartridge is fired, the barrel may recoil or rebound along with the ;setting gun. When such rebounding action takes place,

lit occurs before the head of the anchoring element has reached the member or members, to be fastened and it increases the likelihood that the head will pierce through the member rather than holding it against the receiving material.

The primary object of the present invention is to provide a setting gun which assures a tight bearing of the members to be fastened against the receiving material, especially during the entire driving-in process.

In accordance with the present invention, the barrel of the setting gun is axially displaceable within the gun housing and, in addition, it is also axially displaceable with regard to a member in the housing which forms the cartridge chamber. The rear end of the barrel facing the cartridge chamber is provided with a shoulder surface, facing the opposite direction from the muzzle end of the barrel, and positioned so that it is exposed to the explosive gases developed when a cartridge is fired.

The action of the explosive gases against the barrel forces or displaces it forwardly in the firing direction so that the barrel is pressed in the direction of'the receiving material, while the member forming the cartridge chamber in which the reaction forces are produced can recoil with the gun housing away from the receiving material. The explosive gases, which act on the shoulder surface, provide a force directed toward the receiving material the size of which depends on the pressure generated by the explosive gases and on the area of the shoulder surface on the barrel. While the pressure is determined by the size of the cartridge and the size of the chamber in which the explosive gases are released, the force can be varied by a selection of the shoulder surface area. The essential characteristic of the invention is that the force for displacing the barrel toward the receiving material acts at the time when the barrel in conventional guns tends to be lifted off the material, due to the recoil action, and results in the loss of the tightly held bearing contact of' the members to be attached to the receiving material. The force transmitted over the barrel to the receiving material is independent of the force with which the gun is pressed against the receiving material for readying it for firing. Preferably, this arrangement is used in a setting gun which employs a piston guided in the barrel for driving in the anchoring element.

In the simplest embodiment, the member forming the cartridge chamber is arranged as a part of the housing itself. In such an arrangement the bore can then extend directly up to the rear end of the barrel. As a result, the shoulder area against which the explosive gases act is provided between the outside diameter of the barrel and the diameter of the bore.

In another embodiment the member forming the cartridge chamber can be detachably mounted within the gun housing. This arrangement is particularly advantageous for purposes of manufacture and facilitates the exchangeability of the member, which is subject to considerable wear. Another advantage of such an arrangement is that the member can be removed for various manipulations, such as loading and ejecting the cartridge, which simplifies these different steps considerably. To afford a connection of the member to the gun housing a screw thread, a bayonet lock or similar arrangement can be used.

To provide a uniform force acting on the barrel so that it does not become jammed, it is advisable to arrange the surface against which the explosive gases act, if the subdivision of the surface should be necessary, symmetrically of the barrel axis. This condition can be met with particular advantage by the use of a ring shoulder surface extending about the barrel bore and such a surface is easy to form.

To assure ease in the axial displacement of the barrel within the gun housing, the barrel is guided within the housing by a running fit. The resulting play between the barrel and housing permits a portion of the explosive gases to escape unused. Therefore, it is preferable if the member forming the cartridge chamber is designed with a cylindrically shaped portion of its axial length extending into the rearward end of the barrel with the diameter of the cylindrically shaped portion being greater than the diameter of the bore at the rearward end of the barrel whichserves to guide the trailing end of the piston. As a result, the surface on the barrel encircling the trailing end of the bore can be used as the surface against which the explosive gases act in displacing the barrel forwardly against the receiving material. The fit of the member into the rear end of the barrel can be a sliding or a push fit.

The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawings and descriptive matter in which there is illustrated and described a preferred embodiment of the invention.

BRIEF DESCRIPTION OF THE DRAWING In the drawing:

FIG. 1 is aside view ofa setting gun, partly in section, embodying the present invention; and

FIG. 2is a partial sectional view, on an enlarged scale, of a portion of the gun shown in FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION A setting gun is shown in FIG. 1 consisting of a gun housing 1 forming an elongated passage la and with a handle 2 and trigger 3 attached to one end of the housing. Abarrel 4 is axially displaceably mounted within the passage la in the gun housing 1 and forms a bore in which a piston 5 is guided for use in driving anchoring element 6 as shown positioned in muzzle end of the bore. At the rear end of the barrel 4, that is, the opposite end from the muzzle end, a member 7 is positioned within the gun housing which forms a chamber 7a in which a cartridge 8 can be positioned. The rear end of the barrel is formed with an annular skirt 4 which laterally encloses a cylindrically shaped portion 7b of the member 7. In other words, the cylindrically shaped portion 7b extends forwardly into a recess formed in the rear end of the barrel 4.

When the gun is being used, the barrel 4 must be pressed in the direction opposite to the firing direction against a bolt 9 biased on the firing direction by a compression spring 10, for positioning the cartridge 7 in the chamber 7a in the range of firing pin 11. in FIG. 1, the setting gun is shown in the position ready to be fired, that is, with the barrel axially displaced rearwardly against the force of the spring 10. Normally, this rearward displacement is achieved by pressing the muzzle end of the barrel against the receiving material into which the anchoring element is to be driven or against a member supported on the receiving material through which the anchoring element is to be inserted for securing the member to the receiving material. When the cartridge is fired, the explosive gases developed by such firing act through the cartridge chamber, open to the rearward end of the bore in the barrel act against the bottom or rearward surface of the piston 5a and also on the ring shaped shoulder surface 411 laterally encircling the end of the bore facing toward the adjacent end surface of the cylindrically shaped portion 7b of the member 7. As a result, both the piston 5 and the barrel 4 are propelled in the firing direction with the propelling force holding the barrel against the receiving material or the member to be attached to the receiving material.

As mentioned above, the piston is guided within the bore in the barrel and it has an enlarged rear end 5b and an axially extending shank end 50 having a smaller diameter than the rear end. Similarly, the bore in the barrel has a small diameter forward end 4b and a larger diameter rearward end 4c. The rear end 5b of the piston 5 is guided within the larger diameter end 4c of the bore while the smaller diameter shank 5c of the piston is guided within the smaller diameter forward end 4b of the bore. The barrel can also consist of several parts. The individual parts of the barrel can bear directly on one another in the axial direction or they can bear on one another with the interposition of spring elements.

As shown on an enlarged scale in FIG. 2, the end surface 5a of the piston 5 against which the explosive gases act in propelling the piston forwardly is located across the opening into the cartridge chamber 8 within the member 7. The piston extends slightly rearwardly of the end of the bore in the barrel holding the piston so that it projects rearwardly from the ring shoulder surface 4a. Further, the axial length of the cylindrically shaped portion 7b of the member 7 is less than the axial dimension of the annular skirt 4 on the rearward end of the barrel so that the shoulder surface 4a is spaced in the axial direction from the juxtaposed end surface of the cylindrically shaped portion 7b. Accordingly, as the explosive gases commence to drive the piston through the bore in the barrel, an opening is provided between the end surface 5a of the piston and the cartridge chamber so that the explosive gases flow into the space between the member 7 and the shoulder surface 4a for displacing the barrel forwardly through the passage la in the gun housing 1. The area of the shoulder surface 4a is determined by the radial dimension extending between the bore and the inner surface of the annular skirt 4'. As the barrel is pressed forwardly by the explosive gases it slides relative to the member 7 with the annular skirt 4 forming a guiding surface for the trailing end of the barrel.

While a specific embodiment of the invention has been shown and described in detail to illustrate the application of the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles.

What is claimed is:

1. In a setting gun using an explosive charge for driving anchoring elements into a solid receiving material, comprising a gun housing forming an axially extending passage providing a muzzle opening from one end of the housing, a barrel having a bore extending axially therethrough and mounted for axial displacement within the passage in said gun housing and having one end arranged to extend outwardly from the muzzle opening, a member mounted in said housing at the opposite end of said barrel from the muzzle opening, said member forming the chamber arranged to receive a cartridge and the chamber being open to the bore in said barrel. wherein the improvement comprises that said barrel is axially displaceable within said housing relative to said member, the end of said barrel adjacent to and facing toward said member having a shoulder positioned within the path of the explosive gases generated when a cartridge is fired within the chamber in said member so that the explosive gases exert a propulsive force against the end of said barrel for displacing it in the direction of the muzzle opening in said housing.

2. In a setting gun, as set forth in claim 1, including a piston mounted in the bore in said barrel and axially displaceable to said barrel under the propulsive forces generated by the explosive gases for driving an anchoring element from the bore in said barrel.

3. In a setting gun, as set forth in claim 2, wherein the bore in said barrel has a larger diameter for the portion extending from the end containing the shoulder than the remaining portion extending therefrom to the muzzle end of said barrel, and said piston having a rear end portion arranged to be displaced through the end of the bore adjacent the cartridge chamber and said rear end portion having a diameter approximately equal to the larger diameter of the bore so that the rear end of said piston can slide in said bore, and said piston having a forward end portion extendingaxially from the rear end portion toward the muzzle opening and having a diameter approximately equal to the smaller diameter of the remaining portion of the bore so that the forward end of the piston can slide through the forward end of the bore.

4. In a setting gun, as set forth in claim I, wherein said member forming the cartridge chamber is detachably connected to said housing.

5. In a setting gun, as set forth in claim 1, wherein said shoulder is ring shaped and extends around and is located radially outwardly from the end of the bore in said barrel adjacent to said member.

6. In a setting gun, as set forth in claim 4, wherein said barrel has an annular skirt extending from the end forming said shoulder in the direction opposite to the muzzle opening, said annular skirt laterally closes at least an axially extending portion of said member, the portion of said member enclosed by said annular skirt being cylindrically shaped and having a diameter greater than the diameter of the bore in said barrel at its end adjacent said member.

7. In a setting gun, as set forth in claim 6, wherein said ring shaped shoulder having a dimension in the radial direction of the bore equal substantially to the difference between the radius of the end of the bore in said barrel adjacent said member and the radius of the interior surface of said annular skirt.

8. In a setting gun, as set forth in claim 6, wherein said member extends radially outwardly from the end of the cylindrically shaped portion thereof which is spaced more remotely from the shoulder on said barrel and forms a shoulder thereon against which the rearward end of said annular skirt contacts, and the axial dimension of said cylindrically shaped portion from the shoulder on said member to its end adjacent said shoulder on said barrel is less than the axial length of said annular skirt so that the end of said cylindrically shaped portion adjacent said shoulder on said barrel is spaced in the axial direction from the shoulder on said barrel.

9. In a setting gun, as set forth in claim 8, wherein spring means are located within said housing for biasing said barrel in the axial direction toward the muzzle end of said housing and said barrel. being axially displaceable through said housing toward the cartridge chamber against the spring biasing action for moving said barrel into the firing direction.

10. In a setting gun, as set forth in claim 8, wherein the opening from the cartridge chamber in said member to the end of said bore diverges outwardly to a diameter less than the diameter of the bore adjacent to the end of said member, and said piston extending rearwardly from the end of said bore into the space disposed between said ring shoulder and the juxtaposed end of said member so that the rearward end of said piston extends across the opening from the cartridge chamber to the end of said bore.

Claims

1. In a setting gun using an explosive charge for driving anchoring elements into a solid receiving material, comprising a gun housing forming an axially extending passage providing a muzzle opening from one end of the housing, a barrel having a bore extending axially therethrough and mounted for axial displacement within the passage in said gun housing and having one end arranged to extend outwardly from the muzzle opening, a member mounted in said housing at the opposite end of said barrel from the muzzle opening, said member forming the chamber arranged to receive a cartridge and the chamber being open to the bore in said barrel, wherein the improvement comprises that said barrel is axially displaceable within said housing relative to said member, the end of said barrel adjacent to and facing toward said member having a shoulder positioned within the path of the explosive gases generated when a cartridge is fired within the chamber in said member so that the explosive gases exert a propulsive force against the end of said barrel for displacing it in the direction of the muzzle opening in said housing.

3. In a setting gun, as set forth in claim 2, wherein the bore in said barrel has a larger diameter for the portion extending from the end containing the shoulder than the remaininG portion extending therefrom to the muzzle end of said barrel, and said piston having a rear end portion arranged to be displaced through the end of the bore adjacent the cartridge chamber and said rear end portion having a diameter approximately equal to the larger diameter of the bore so that the rear end of said piston can slide in said bore, and said piston having a forward end portion extending axially from the rear end portion toward the muzzle opening and having a diameter approximately equal to the smaller diameter of the remaining portion of the bore so that the forward end of the piston can slide through the forward end of the bore.

4. In a setting gun, as set forth in claim 1, wherein said member forming the cartridge chamber is detachably connected to said housing.

9. In a setting gun, as set forth in claim 8, wherein spring means are located within said housing for biasing said barrel in the axial direction toward the muzzle end of said housing and said barrel being axially displaceable through said housing toward the cartridge chamber against the spring biasing action for moving said barrel into the firing direction.