US3137195A

US3137195A - Centering and guiding means for metal studs

Info

Publication number: US3137195A
Application number: US153349A
Authority: US
Inventors: Jr Harry Z Rosenberg
Original assignee: American International Tool Co Inc
Current assignee: American International Tool Co Inc
Priority date: 1961-11-20
Filing date: 1961-11-20
Publication date: 1964-06-16
Anticipated expiration: 1981-06-16

Description

June 1964 H. z. ROSENBERG, JR 3,137,195

CENTERING AND GUIDING MEANS FOR METAL STUDS Filed NOV. 20, 1961 FF 5 3 F! G 4.

INVENTOR Harry 2. Rosenberg,Jr.

ATTORNEY United States Patent fiice 3,137,195 Patented June 16, 1964 3,137,195 CENTERING AND GUIDlNG MEANS FQR METAL STUDS Harry Z. Rosenberg, In, Miami Beach, Fla., assignor to American International Tool Corporation, Miami Beach, Fla, a corporation of Florida Filed Nov. 20, 1961, Ser. No. 153,349 3 Claims. (Cl. 85-10) The present invention relates to centering and guiding means for metal studs, nails, pins and like fastening devices which are fired into surfaces such as concrete, masonry, steel and the like, by the use of an explosively ac tuated hand tool.

Heretofore, a number of centering and guiding means of this type have been proposed but due to their structural shapes and/ or the material from which they are fabricated, they have not been found entirely satisfactory in performance.

It has previously been considered expedient to make these members of a material which will be consumed due to the heat and impact of the explosion during its travel through the tool. It has now been found that this type of material does not give entirely satisfactory performance.

It is therefore an object of the present invention to provide improved centering and guiding means of the aforesaid type which are made from a plastic material which has the characteristics of withstanding the force of the explosion and remaining nearly intact throughout its travel through the tool.

It is a further object of the present invention to provide improved centering and guiding means of the aforesaid type which are capable of substantially increasing the penetration for a given exposive charge over those previously proposed.

It is a still further object of the present invention to provide an improved centering and guiding means which is so constructed as to be usable with various shank diameters of nails and the like.

A still further object of the present invention is to provide an improved cap for an explosively driven nail or the like which has a shape capable of increasing the penetration thereof for a given explosive charge.

Other objects and the nature and advantages of the pres ent invention will become apparent from the following description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a view partly in section of a part of the front end portion of the barrel of an explosively actuated hand tool and containing in the bore thereof a fastening element, the front and rear end portions of which are provided with centering and guiding members embodying the present invention;

FIG. 2 is a longitudinal sectional view similar to FIG. 1;

FIG. 3 is a top plan view of the front centering and guiding member; and

FIG. 4 is a sectional view of the rear centering and guiding member. The centering and guiding members in accordance with the present invention are for use with various types of fastening elements, such as pins, nails, threaded studs, eyelet nails, and the like which are fired into steel, concrete, masonry and like materials by the use of explosively actuated hand tools. When the term stud is used in the claims, it should be understood that any of these conventional fastening elements are contemplated.

As illustrated in FIGS. 1 and 2, a threaded stud is shown in the barrel bore 12 of an explosively actuated hand tool. The front centering and guiding element 14 is mounted on the shank portion 16 of the stud and the rear centering and guiding element 18 is mounted on the head portion 20 of the stud. These front and

rear elements

14 and 18 cooperate to insure true centering of the studs in the tool barrel bores in which they are used and also true guidance of the studs in their travel through the bores. The rear element 18 also serves the important function of sealing otf the gases resulting from the explosive charge and increasing the penetration of the stud in the hard surface into which it is fired.

The rear end centering and guiding member, best shown in FIG. 4, is of generally cup shape with a central chamber 22 of such size as to frictionally grip the rear head portion 20 of the stud. The length of the member may be varied as desired, but it should be sufficient to provide ample contact with the tool barrel and to remain on the fastening element. The outside diameter 24 at the rear end of the element 18 is such as to properly fit the tool barrel, and preferably the remainder of the outside diameter 26 is of a slightly lesser diameter than at 24 to reduce frictional contact with the barrel yet to yield a sufficient seal and guidance means.

The inside chamber 22 may be provided with small wedges or threads 28 on the lower portion thereof. These indentations 28 provide for a better grip against threaded studs and also serve as a ledge for holding the head of a nail in its proper position. A conical hole 30 is provided in the upper wall 32 of the inside chamber 22. This hole 30 provides for an ease in molding and ejection from the mold and also assists in holding the fastening element in the member 18.

The upper outer end of the element 18 is provided with a cup-shaped depression 34 and the edges 36 surrounding the cup-shaped depression 34 are sharp and square to provide for a better seal against the explosive gases and thus prevent them from creeping around the edges of the member 18. The edges 36 are so designed in conjunction with the cup-shaped depression 34 that the explosive force will push the edges against the walls of the barrel maintaining an excellent seal during its travel along the barrel.

The front centering and guiding element 14 has a circular body portion 40 having a diameter intermediate between the outer diameter of the shank portion 16 of the stud 10 and the inner diameter of the barrel of the driving tool. A plurality of flexible inner protrusions or fins 42 are provided integral with the body portion 40 and extending inwardly therefrom. The inner ends of said inner protrusions 42 form a diameter which will frictionally engage the shank portion 16 of the stud. The inner protrusions 42 are capable of bending outwardly to engage shank portions of varying diameters. Thus, for example, the same element 14 can be used with shank diameters varying from inch up to inch.

The element 14 is also provided with a plurality of flexible outwardly extending protrusions or fins 44 which are integral with the body portion 40. As illustrated, there are eight inner protrusions 42 and eight outer protrusions 44 in staggered arrangement about the body portion 40. The outer diameter of the ends of the outer protrusions 44 is such that they contact the barrel of the driving tool.

It should be noted that the inner and outer protrusions are so arranged and spaced so that the bending of the inner protrusions due to a larger shank diameter does not add to the pressure of the outer protrusions on the barrel of the tool which must remain constant.

The rear centering and guiding element 18 is made of a plastic material which is capable of withstanding the force and heat of the explosion without disintegrating and which will remain intact throughout the travel of the stud through the tool. On the other hand, the front centering and guiding element 14 may be made of any plastic material which can be molded or extruded into the shape illustrated and in which the protrusions will be flexible.

I It has been found that the only material suitable for i use as the rear centering and guiding element 18 is a thermoplastic polycarbonate resin. Examples of such polycarbonate resins are Lexan, manufactured by' the .G'ener'al Electric Company, and Merlon, rnanufactured by the Mobay Chemical Company. The polycarbonate name is taken from the carbonate linkage which joins the organic units in the polymer and which is an integral part of the-main polymer chain. Such polycarbonate resins can be made by combining a bifunctional phenol,

, bisphenol-A, with a carbonyl chloride by splitting out hydrochloric acid' to give a linear polymer consisting of V bi'sphenol groups joined together by carbonate linkages as represented by the following formula:

resins, andothers. A simple testwill show :the unexpected-results obtained using the present polycarbonate resinrear centering and guiding element'18 as against an element made of polyethylene. "Using a pin 2%" long with a shank diameter of Y with the polycarbonate resin rear element, a penetration to 78" below the surface of the concrete fora total of three inches of penetration. Using the same pin, with the same strength explosive charge but with a polyethylene rear element, a total penetration of 1% inches is obtained. With heavier explosive charges even more spectacular results are obtained using the guide elements in accordance with-the present invention. V

The front centering and-guiding element .14 can be extruded from a vinyl resin, for example, in a continuous extrusion of the cross section shown in FIG. 3 and then cut into the desired lengths.

It should be noted that although the drawings show the rear element as separate from the stud, it is equally. effective when the rear element is molded ontothe stud.

fpropionate, polyethylene, nylon, polypropylene, vinyl at least a portion of said .cap generally corresponding to the size of said barrel bore, the rear end portion of said cap priorto explosion having a cup-shapeddepres-Y sion in the central portion thereof surrounded by a'lip,v which is sharp and square to yield a gas seal during the travel of the element alongthe barrel, said cup-shaped I depression havinga substantially fiat bottorn'surface there- 1 tively hard material, said element'having' a front guiding and'centering means retained on said element shank portion, said element'havinga" rear guiding and centering 1 means which comprises a cap made {of a thermoplastic polycarbonate resin and being retained'over the near end of the fastening element, said cap having a hollow. central chamber, the outside diameter of at leasti a portion'of said cap generally, corresponding to the size-of said barrel bore the rear end portion of fsaid. cap, prior 9 to explosion having a cup-shaped'depi essionin the cen-' m portion thereof surrounded by a' lip which is. sharp and square to yield a gas seal, during the travel of the element alonglthe barrel, saidcup-shaped depression hav- 7 ing a substantially fiatbottom surface therein.

1.3. A fastening element in accordance with claim wherein said front guiding and centering means comprises a circular body portionhaving a-diarn'eter intervmediate between the outer diameter ofthe shank portion of the element 'and the inner diameter of the barrel of thedriving' tool, a plurality of flexible innerv protrusions integral with said bodyportion and extending inwardly therefrom, anda plurality of flexible'outer pro- It will be obvious to those skilled in the art that various changes may be made withoutdeparting from the spirit,

of the invention and therefore the invention is not'limited said shank portion having a front end part tapered to' a point to facilitate the insertion of the'element into said relatively hard material, said element having a rear guida thermoplastic polycarbonate resin and being retained over the rear end of the fastening element, said cap having a hollow central chamber, the outside diameter of 'to what is shown in the drawings and described in the? ing and centering means which comprises a cap made of trusions integral with said body portion and extending outwardly therefrom, said body portion, inner protrusions and outer protrusions all extending'in the same plane,.

said innerprotrusionsand said outer protrusionsbeing capable of bending as necessary to accommodate various sizes of shanks and barrels respectively.

References Cited in the file of this patent I UNITED STATES PATENTS 2,578,809 Ketchum" Dec. 18, 1951 2,676,508 Erickson Apr.'27, 1.954 2,722,004 Webb'er 6t al.f Nov. 1, 1955, 2,761,348 Williams et al Sept. 4, 1956 2,820,412 Beeuwkes et a1. Jan. 21, 1958 2,911,911 White i Nov. 10, 1959 2,920,563 De Caro 'Jan. 12, 1960 2,983,224 Pros'en et al. May 9, 1961 3,007,726 Palldil Nov. 7, 1961 FOREIGN PATENTS i 228,465 Australia 1 Oct. 9, 1958 737,968 Great Britain Oct. 5,-1955 Y OT E -R FEREN ES Lexan Polycarbonate Resin, General Electric, Chem.

Development'Dept, April 1958 (reprinted fromv Modern Plastics Magazine, April 1958). 1

2. A fastening element for insertion into relatively hard material by its ejection through the bore of the barrel of an explosively actuated driving tool, said element comprising a shank portion and a rear end portion, said shank portion having a front end 'parttapered to a point to. facilitate the insertion of the element into said rela-

Claims

2. A FASTENING ELEMENT FOR INSERTION INTO RELATIVELY HARD MATERIAL BY ITS EJECTIN THROUGH THE BORE OF THE BARREL OF AN EXPLOSIVELY ACTUATED DRIVING TOOL, SAID ELEMENT COMPRISING A SHANK PORTION AND A REAR END PORTION, SAID SHANK PORTION HAVING A FRONT END PART TAPERED TO A POINT TO FACILITATE THE INSERTION OF THE ELEMENT INTO SAID RELATIVELY HARD MATERIAL, SAID ELEMENT HAVING A FRONT GUIDING AND CENTERING MEANS RETAINED ON SAID ELEMENT SHANK PORTION, SAID ELEMENT HAVING A REAR GUIDING AND CENTERING MEANS WHICH COMPRISES A CAP MADE OF A THERMOPLASTIC POLYCARBONATE RESIN AND BEING RETAINED OVER THE REAR