US2770194A - Method of and cartridge for loading powder-actuated tools - Google Patents

Description

Nov. 13, 1956 R. J. KOPF ETAL 2,770,194 METHOD OF AND CARTRIDGE FOR LOADING POWDER-ACTUATED TOOLS Filed Oct. 22, 1954 INVENTORS. ROWLAND J. KOPF ROGER MARSH BYBW M A TTORNEYS.

nite States lVIETHOD OF AND CARTRIDGE FOR LOADING POWDER-ACTUATED TOOLS Application October 22, 1954, Serial No. 464,024

3 Claims. (Cl. 102-38) This invention relates broadly to powder-actuated tools of the type used in setting fasteners and more particularly to the cartridges therefor.

It will be understood that so-called powder-actuated tools utilize a blank cartridge to drive a penetrating fastener, the fastener being propelled along a barrel which is held against the work. Usually, the cartridge and fastener are breech loaded as separate items, and the base of the fastener may not always be seated in the same position relative to the mouth of the cartridge case at the instant of firing. When the initial free air space between the cartridge and fastener changes from shot to shot in the course of a job, the driven force and penetration of the fasteners vary, although the fasteners, cartridges and work are all uniform. It has been proposed that unit loads be supplied by the manufacturer, the fastener being secured to the case, as by cannelures, so that the free air space is held to a predetermined uniform value, but such unitized loads are not always satisfactory. In many instances, the operator prefers to make his own selection of cartridge and fastener on the site to fit the requirements of the job, and such selection is not conveniently possible when the fasteners and cartridges are supplied as unitized assemblies.

Accordingly, it is an object of the invention to provide a cartridge which may be used with a variety of fasteners, yet which insures predetermined behavior. The selection of cartridge and fastener is made in the field, yet any given combination is designed to produce predetermined power or penetration in a structure of known resistance to penetration. In addition, the invention contemplates the use of a cartridge which permits the operator to control the driving force and thereby the penetration, within limits, according to his needs, as they are effected by the type of fastener utilized and the character of the work material encountered.

Briefly, the cartridge may be of any type or material, but the mouth of the case projects beyond the charge so as to receive the base of a fastener. This open mouth portion of the case and the base of the fastener are then designed to have a force fit with one another when the fastener is seated at predetermined depth. In one embodiment of the invention, the mouth portion of the case is formed with an inwardly-projecting boss, which extends longitudinally and tapers outwardly in the forward direction. In use, the operator selects the fastener and cartridge desired, and the base of the selected fastener is forced within the case so as to jam on the boss, such a unit being loaded in the tool with assurance that the free air space will remain fixed. Alternatively, a tongue may be cut from the wall of the case adjacent the mouth, this tongue being bent inwardly so as to function as a spring arm in holding the fastener in proper position. If desired, the fastener may include a base section of reduced diameter which telescopes within the case and a body section of somewhat larger diameter which seats against the end of the case.

When it is desired to provide for variation in the drivatent ing force of the cartridge, a series of longitudinally-spaced ears are cut or otherwise formed in the wall of the case, any one of which may be pressed inwardly at the time of use, as by the point of a fastener. Conversely, the mouth of the case might be formed with thread-like bosses, so that a threaded-base type of fastener may be screwed inwardly varying amounts. In all instances, however, the fastener is of a type which permits the base thereof to be inserted and secured within the mouth of the case, or the case is formed with means for predetermining the depth of seating.

Other features of the invention will be in part apparent from and in part pointed out in the following detail description taken in connection with the accompanying drawings, in which:

Fig. l is a sectional view illustrating an assembly of cartridge and fastener loaded within the barrel of a powder-actuated tool;

Fig. 2 is a side elevation of a cartridge case embodying the invention, parts being broken away;

Fig. 3 is a view similar to that of Fig. 1, but showing an embodiment whereby the initial air space is varied to control the force of penetration of the fastener, within limits; and

Fig. 4 is a view similar to that of Fig. 2 but showing a cartridge of the Fig. 4 type.

Referring to the drawings, there is shown a barrel 1 of a powder-actuated tool, the barrel being adapted to receive a cartridge generally designated 3 and a fastener generally designated 5. The barrel is of a breech-loading type, a breech bolt 7 being closed against the breech end 9 of the barrel. In use, the muzzle (not shown) is held against the work surface when the cartridge is fired, so that the fastener is propelled along the barrel and into the work.

Such tools, as is known in the art, are employed to drive penetrating fasteners in a wide variety of materials, including metal plate, concrete and wood. Necessarily, such materials have different resistances to penetration. Also, it is customary to use different types of fasteners, the penetration of which will vary with their weight, shape and size. In a given job, it is accordingly necessary to use a cartridge of predetermined power in achieving proper penetration. If the cartridge is too powerful, the fastener may overly penetrate the work or may be driven entirely through a portion of'the work. On the other hand, a cartridge of insufficient power may not produce the desired amount of penetration for securing several parts in tight assembly. In the usual case, the power is controlled by the charge within the cartridge, cartridges of different loadings being supplied by the manufacturer.

Where a cartridge of suitable power is not available, however, some operators will endeavor to control the penetration by varying the free air space between the mouth of the cartridge and the base of the fastener. For example, when the base of the fastener is pressed tightly against the front of the charge, the free air space is at a minimum and propelling force at a maximum value. As the free air space is increased (the base of the fastener being spaced forwardly of the charge), the propelling force is somewhat reduced. Such a procedure leads to non-uniform penetration, however, because it is difiicult to maintain a uniform distance between the fastener and cartridge case over a number of shots, when using conventional cartridges and fasteners. Unit loads (the fastener being secured to the cartridge) assure more uniform penetration, but they do not permit variation in the driving force or penetration, and their use necessarily restricts the operator in the selection of a cartridge-fastener combination for a given job.

Accordingly, this invention contemplates the provision of a cartridge which permits the operator to make a selec'tion o'f cartridge and fastener and to form a unit load of predetermined power on the site. In Fig. 2, there is shown a cartridge case 3 having a cylindric wallllwhich is formed at one end with arimmed head 13 and at the other endwith an open mouth 15-. The case may be made of steel, copper or aluminum, but it is preferable to use cartridge brass. Also, the cartridge may have a centerfire, rimfire or other type of primer.

The loadingor charge 17 is confined behind a wad 19, which wad is spaced rearwardly within the case from the mouth end 15"of the case so as to'admit the base of a fastener. The wall 1 1 of the case is then deformed at point 21 sp'aced rearwardly of the mouth 15 and forwardly of the wad19 for engagement with the base of a fastener. I V

In the embodiment illustrated in Figs. 1 and 2, this deformation 21 is in the form of a tongue defined by a cut 23 in the wall 11 of the case, the tongue projecting rearwardly and being bent inwardly, as illustrated. Such a cartridge is intended to be used with a fastener having a base portion 25 of such diameter as to telescope within the mouth portion of the case. The fastener otherwise .has a penetrating point 27 and a shank 29 which is adapted to embed within the work. The diameter of the shank portion will depend upon the type of work encountered. The base section 25, however, should have a reasonably close fit with the mouth portion of the cartridge, and the fastener may have an intermediate shoulder 31 of somewhat larger diameter, such intermediate section 31 fitting closely with the bore of the barrel so as to function as a gas check. I

In operation, the operator selects a cartridge of suitable power and a fastener suitable for the particular job at hand. The fastener is then seated within the cartridge prior to loading, the base portion 25 being telescoped within the case beyond the tongue 21 and being retained therein by the spring-gripping force of the tongue. Normally, the fastener would be pushed in until the shoulder 31 thereon abuts against the end 15 of the cartridge case. The assembly of cartridge and fastener is then loaded within the tool and fired in the usual manner. It will be apparent that with this arrangement, the free air space (as defined by the space between the wad 19 and the base end 33 of the fastener) is predetermined, assuming that the shoulder 31 is pressed against the end of the cartridge case.

Under some circumstances, it is desirable to provide for variation of the free air space, within predetermined limits, so as to provide the operator with limited control over the power of the cartridge. In that event, a cartridge 203, such as shown in Fig. 3, is supplied. In this instance, there are a series of longitudinally-spaced tongues 221, but these tongues are not bent inwardly from the wall 11-by the manufacturer.

In operation, one of the retaining elements, such as that shown at 221C, is pressed inwardly by the operator using the pointed end 227 of a fastener, for example. The fastener is then inserted until the base 225 thereof abuts against the inwardly-bent retaining element 221C, so that barrel, and the cartridge case has an equal internal diameter, the firing chamber being of somewhat larger diameter so as to accommodate the wall of the case. The fastener is retained in the case by a press fit or by a deformation, such as shown in Figs. 1 and 2 at 21.

From the foregoing description, it is apparent that those skilled in the art will understand the structure, function and mode. of operation of the invention herein disclosed, and appreciate the advantages thereof. Although several embodiments have been disclosed in detail, it is to be understood that the invention is not limited thereto, but the drawings and description thereof are to be understoodas being merely illustrative. It is realized that many modifications and variations will present themselves to those skilled in the art without departing from the spirit of this invention or the scope thereof as set forth in the appended claims.

Having thus described the invention, what is claimed and desired to be secured by Letters Patent is:

I l. A cartridge for powder-actuated tools comprising an open mouth case, a charge of propellant contained within said case, charge-confining wad means located forwardly of said charge and rearwardly of said open mouth, the wall of the case having a series of longitudinallyspaced weakened sections spaced forwardly of said wad means and rearwardly of said mouth, said weakened sections being bendable inwardly for engagement with the base of a fastener to be'seated therein.

' 2. A cartridge asset forth in claim 1, wherein said weakened sections are defined by U-shaped cuts, thereby providing a plurality of longitudinally-spaced tongues which are bendable inwardly.

3. A cartridge for powder-actuated tools comprising an open-mouth case, a charge of propellant contained within said case, charge-confining wad means located forwardly of said charge but rearwardly of said open mouth, the Wall of the case having at least one weakened section spaced forwardly of said wad means and rearwardly of said mouth, which is bendable inwardly for engagement with the base of the fastener to be seated therein, said weakened section being defined by a U-shaped cut References Cited in the file of this patent UNITED STATES PATENTS 299,162 Peters May 27 1884 651,558 Ryland's June 12, 1900 1,376,530 Greener May 3, 1921 FOREIGN PATENTS 24,289 Great Britain 'of 1894 306,404 Germany Dec. 6, 1920 502 872 Belgium Aug 14, 1952 If the penetration is excessive for the

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