US2794251A

US2794251A - Metal cutting ax

Info

Publication number: US2794251A
Application number: US425399A
Authority: US
Inventors: Claude M Towne
Original assignee: STEIN BROS Mfg CO
Current assignee: STEIN BROS Mfg CO
Priority date: 1954-04-26
Filing date: 1954-04-26
Publication date: 1957-06-04
Anticipated expiration: 1974-06-04

Description

v June 4, 1957 c; M. TOWNE METAL CUTTING AX Filed April 26, 1954 United States Patent 2,794,251 METAL CUTTING AX Claude M. Towne, Watertown, Wis.,

assignments, to Stein Bros. Mfg. Co., corporation of Illinois assignor, by mesne Chicago, 11]., a

This invention relates to an ax head for cutting materials by swinging the ax against the material. The particular disclosed ax head is for cutting metal such as sheet or light weight plate although the form of the ax is also appropriate for cutting into walls, partitions, doors and the like.

It is the principal object of this invention to provide a new and improved ax head for cutting materials.

Another object is the provision of an ax head of the character described having a cutting edge shaped to provide maximum shearing of metal for a given blow of the ax.

Another object is to provide an ax head according to the invention having means for preventing the ax from wedging in a cut.

Another object is to provide an ax of the character described having a means for prying the head out of the cut should it become wedged therein.

A further object is to provide an ax head formed of a quantity and kind of material to accomplish the most efficient cutting job of metal and similar materials which is commensurate with practical life.

Other features, objects and advantages of the present invention will be apparent from the following description of a preferred embodiment of the invention illustrated in the accompanying drawings, in which:

Figure 1 is a plan view of the ax head of the present invention mounted on a handle shown in part;.

Figure 2 is an enlarged fragmentary plan view of the blade of the ax shown in Figure 1;

Figure 3 is a fragmentary sectional view taken through the arcuate portion of the cutting edge substantially along line 3-3 in Figure 2;

Figure 4 is a fragmentary sectional view taken through the stop leg and substantially along line 4-4 in Figure 2; and

Figure 5 is a fragmentary enlarged sectional view through the sharpened cutting edge and taken substantially along line 5-5 in Figure 2.

The structure shown for purposes of illustrating the invention is incorporated in a firemans ax. The ax is intended to permit the fireman to break into a locked automobile, through walls, partitions and the like which would be found in a building, or through metal panelling of one kind or another which might be found in a factory building. The ax is particularly formed for shearing metal. The cutting blade has a carefully selected contour for accomplishing the cutting of metal and the material of the ax head is carefully chosen to accomplish the best results.

As shown in Figure 1, the ax head, generally indicated 10, is equipped with an opening 11 for reception of an ax handle 12 of select hardwood. In the particular illustrated form, the rear portion of the head is formed with a pick point 13 as are common on firemens axes. The blade portion 14 of the ax is formed with a cutting edge 15 extending from the leading edge 16 of the head toward the trailing edge 17 and inwardly tostroke of the ax.

"ice

ward the handle opening 11. A stop leg 18 is provided on the trailing edge of the blade and it may be used for stopping the penetration of the head through sheet metal. The general structure of the ax head, therefore, employs a body having a particularly shaped cutting edge and a stop leg adjacent the cutting edge on the trailing side of the ax head.

It is preferable to make the ax head out of a high manganese steel or a silicon bearing steel analogous to chisel steel. In order to cut through sheet metal, the head should have a weight of around 6 lbs. to 8 lbs., a minimum of 4 lbs. being required for an adequate job whereas a weight of over 8 lbs. becomes difiicult for most men to handle. Emergency tools of lesser weight, such as 1% lbs., are less efficient in cutting, however may serve a very useful purpose.

The head may be blanked in a die from a forged head made for a conventional ax. The cutting edge is then ground to the proper proportions to form the cutting ax. After the grinding, it has been found expedient from the standpoint of long life to harden the blade to about 56 to 58 Rockwell (C scale). This is in contrast to the normal ax head which has a hardness of 48 to 50 on the same scale.

The particular form of the cutting edge is important, particularly in achieving the best cutting for a given The piercing point 20 at the leading edge 16 of the ax is adjacent to the sharpened cutting edge portion 21 which slopes only gradually from the point. This portion 21 is at an acute angle to the handle opening so that the piercing point 20 has a rapidly broadening base or a wide angle taper to add strength to the point. It is important that the ax begin to shear material as soon as it enters or pierces. The point 20 may enter through sheet steel, for instance, and the portion 21 of the sharpened cutting edge will immediately begin to shear. This action uses the inertia of the ax head for cutting rather than merely for breaking through the sheet steel.

It has been found that the cutting occurs more easily and gives longer cuts for a given stroke of the ax if the blade is shaped to have convolutions. Thus, immediately adjacent the inwardly inclined portion 21 is a more steeply inclined portion 22 having a reverse curved portion 23 adjacent thereto adjoining a step portion 24 which is substantially straight for some distance. The portion 24 is substantially parallel with the ax handle opening and does not reverse its direction from portion 23 outwardly on the ax blade as this has been found particularly undesirable. At the same time, the portion 24 does not have any appreciable slope toward the ax handle opening. The position of this step portion may be defined herein as having substantially no inclination to the ax handle opening.

A more steeply inclined portion 25 on the sharpened edge gently joins the straight portion 24 with a similar portion 26. The portion 26 has very little inclination to the ax handle opening. and is straight for at least a short distance. The'se straight portions are believed to shear the material in action and utilize the energy of the ax head particularly upon the initial penetration into a sheet of metal. On subsequent cuts after a penetration has been made, the blade of the ax moves quickly into the arcuate portion 28 which is joined to the straight portion 26 by a steeply inclined portion 27. The arcuate portion of the cutting blade has a curvature On a very short radius. Figure 2 is drawn to actual scale of one model of the ax head. The center of curvature of the cutting edge is shown at 29 and thus the radius can be measured as approximately It has been found that the extent of the sharpened arcuate portion 28 is particularly important in obtaining the best cuts. The ax Works best if the movement is between 30 and 40 to the material upon the original entry whereas on succeeding cuts the angle is not so important as the ax moves to the arcuate portion almost immediately.

in the particular ax illustrated, the arcuate portion is curved in the main part. There is a transition between the curved portion and the surface 30 of the pry-out leg or stop leg, a part of .which' transition is sharpened and joined smoothly with the curved portion of the cutting arcuate portion. The actual point at which the sharpened portion stops is indicated as 31. Experimentation has indicated that the sharpened portion should not be carried along the pry-out leg a distance beyond the point marked 32 if the best results are to be achieved. 'Thisdistance is about equal to the radius of curvature of the arcuateportion extending from the transitionpoint"33 on the .cutting edge. Extending the cutting edge beyond the point 32will permit the ax head to easily wedge in an opening.

A failure to extend the cutting edge at least as far as the point 33, the transition point between the arcuate and extended cutting edge, will waste energy in performing the cuts as each cut will not be as long as it would be otherwise. With the ax of the present invention, cuts have been madein 17 ga. steel of beween 6" and 8" per stroke after entry. Heavier metal may be cut but at less distance per stroke.

The ax of the present invention is provided-with a pryout or stop leg 18 which has a rounded surface 30 as is illustrated in Figures 2 and 4. This stop leg is purposely dullso as to stop penetration of the ax through sheet steel and the like. Also, should the ax head become wedged, the pry-out leg 30 may be used to actually release the head simply by appropriate manipulations of the handle 12.

The cutting edge itself is preferably formed as is shown in Figures 3 and to attain longest possible life and to stand up under the impact blows of cutting metal. The cutting edge 35 is sharpened, however, the

sides

36 and 37 leading to the cutting edge are slightly convex or the blade is cannelled or has a rolled edge, according to the usual reference to such cutting edges in the trade. The cutting edge preferably has an included angle of 60 between the

ground portions

36 and 37 and is hardened as mentioned above after grinding. The particular form of the cutting edge is carefully maintained, however, the stop leg may be changed in form without particularly detracting from its purpose. The rearward portion 38 of the stop leg as illustrated comes to a blunt point whereas another form could be as readily utilized.

While the primary function of the present ax head is for use as a fire fighting tool, it can also be used as a rescue device or for a scrap breaking hammer and ax. The tool is a hand tool intended only for such use, however, the principal of the cutting edge may be utilized in other tools or for use ondifierent materials.

While I have shown and described a particular embodiment of my invention, it is to be understood that it is capable of many modifications. Changes, therefore, in the construction and arrangement may be made without departing from the spirit and scope of the invention as disclosed in the appended claims.

I claim:

'1. An ax head for cutting metals, comprising: an ax body having a handle opening therein and a cutting blade extending generally in the direction of the handle opening, said blade having leading and trailing edges with a cutting edge extending across a part of the blade portion from the leading edge in a direction diagonally toward the handle openingand the trailing edge, said cutting edge having alternate portions sloping toward the handle opening joined by step portions generally parallel to the handleopening, said portions merging gently to form a wavy cutting edge; an integral stop leg for arresting movement of the head through metal, said leg extending from the trailing edge in a direction diagonally toward the handle opening and the leading edge, said leg being dull for the greater portion; and a sharpened arcuate portion joining said wavy cutting edge and said stop leg.

"2. Anax' head as specified in claim 1 wherein the cutting blade is sharpened to include about 60 between sides thereof.

'3. An ax head as specified in claim 1 wherein the ax head has a weight of at least'four pounds and has a hardness in excess of 50 and no greater than 5 8 Rockwell (C scale).

4. An ax head as specified in claim 1 wherein said cutting edge at the leading edge-of the blade provides a piercing point with the sharpened cutting edge immediately adjacent the point sloping only slightly toward the handle opening, said edge having a portion of greater slope toward the handle opening adjacent thereto joined to the step portion closest to the piercing point.

5. An axhead for cutting metals, comprising: an integral ax body having means for attaching a handle thereto and a blade portion; a cutting edge extending across a part of the blade portion diagonally from the front of the blade toward the rear'thereof and toward the handle attaching means, said edge having alternate portions of greater and lesser slope toward the handle attaching means forming a stepped cutting edge; an arcuate cutting section at the inner extent of said cutting edge and having a relativelyshort radius of curvature; and a blunt stop leg on the rear portion or" said ax body immediately adjacent and joining the arcuate cutting section for stopping penetration of the ax head through metal and for prying the head out of a cut, a portion of the stop leg next adjacent thearcua-te cutting section being sharpened for a length therealong not substantially greater than the radius'of thearcuate section.

References Cited in the file of this patent UNITED STATES PATENTS 771,419 Conover Oct. 4, 1904 798,141 Morgan et al Aug. 29, 1905 934,008 Olson Sept. 14, 1909 1,033,485 Steel July 23, 1912 1,423,140 Olesberg July 18, 1922 2,017,447 Simmons Oct. 15, 1935 2,075,302 Poe Mar. 30, 1937