US3739664A

US3739664A - Tools and machine parts and methods from inverse draft forging

Info

Publication number: US3739664A
Application number: US00189126A
Authority: US
Inventors: J Swanstrom
Original assignee: Individual
Current assignee: Diamond Tool and Horseshoe Co
Priority date: 1971-10-14
Filing date: 1971-10-14
Publication date: 1973-06-19
Anticipated expiration: 1990-06-19
Also published as: FR2156512B1; SE382766B; DE2201436A1; ES405605A1; IT952022B; FR2156512A1; JPS4847700A

Abstract

The disclosure is directed to the use of forging tools and machine parts by employing a method and structure in the form of a negative draft angle and larger positive draft angle to form tongue or groove elements in the tools and machine parts as forged from the dies. Employment of the negative draft angle with a greater positive draft angle permits tools and machine parts to be formed so that the metal being worked is formed with a continuous uncut and uninterrupted grain flow extending longitudinally of the working member being formed. A negative draft angle of substantially 5 degrees when used with a positive draft of substantially more than 5 degrees has been found to produce excellent results.

Description

United States Patent [1 1 Swanstrom, Jr.

1 TOOLS AND MACHINE PARTS AND METHODS FROM INVERSE DRAFT FORGING [76] Inventor: John E. Swanstrom, Jr., 217 S. 36th Avenue East, Duluth, Minn. 55804 [22] Filed: Oct. 14, 1971 [21] Appl. No.: 189,126

[ 1 June 19, 1973 Primary ExaminerLowell A. Larson Attorney-Everett J. Schroeder, Kenneth D. Siegfried, Joseph E. Ryan 1 ABSTRACT The disclosure is directed to the use of forging tools and machine parts by employing a method and struc ture in the form of a negative draft angle and larger positive draft angle to form tongue or groove elements in the tools and machine parts as forged from the dies. Employment of the negative draft angle with a greater positive draft angle permits tools and machine parts to be formed so that the metal being worked is formed with a continuous uncut and uninterrupted grain flow extending longitudinally of the working member being formed. A negative draft angle of substantially 5 degrees when used with a positive draft of substantially more than 5 degrees has been found to produce excellent results.

10 Claims, 13 Drawing Figures PATENIED 3.739.664

SHEEI E [If 2 F1660 I F1670 FIG. 8., //Z5 t\\\\\ 32 my l ner/0 FIG. 5. LINE 4V INVENTOR PAH/Na John E. Swansfram Jr.

LINE

A 7' TORNE'YS TOOLS AND MACHINE PARTS AND METHODS FROM INVERSE DRAFT FORGING This invention relates to the field of forgings and the tools and dies used therewith and the method incorporated therein.

In the art of forging tools and machine parts, draft angles have always been of a positive nature. That is, the die has always been formed so that there is ample clear ance for the die upon being separated after the part has been forged. Generally speaking, draft angles have ranged from approximately 7 to prevent the forging from sticking to the dies. The draft is always spoken of as originating from the parting line although the draft angle is always measured from the direction of the stroke of the forging press.

Another basic consideration in forming the shape of a piece to be forged, is the fiber direction or flow of the material while being forged. It is generally recognized that forging provides a much stronger article than one 1 which is cast for instance. Casting will produce grains which are generally equally strong in all directions, whereas in the forging, the tensile properties of the forging are stronger along the grain direction than across it, thus producing an added strength. Therefore, forging is stronger in any direction than that of casting of a similar nature due to the work being imparted to the metal. The most important feature of the grain or fiber direction of the metal flow is not so much in the difference in the tensile properties but the ability of the metal along the grain fibers to resist shock, wear, and impact to a much greater extent than when applied across the grain direction. This is particularly important in the casting or forging or machining of different arms, brackets, links, or similar parts in which vibrations or impact takes place.

It has also been recognized that the prior art such as disclosed in U.S. Pat. No. 2,622,464 recognizes that when the fibers of the forging such as the grain flow is cut, by a machining process, the strength which is gained through the forging process is greatly reduced and may even be eliminated for all practical purposes so that the part might just as wellhave been cast in the first place. In other words, any forging which must be machined and particularly with a sharp tool to form a sharp corner or angle in the forging would tend to weaken the tool.

The latter practice is one which is found in U.S. Pat. No. 2,640,381. The latter patent constantly refers to undercutting of certain portions of the tool to achieve what is disclosed herein as a negative draft angle forging. In other words, the present invention eliminates the machining operation from forming the negative draft angle members forming the machine parts or tools. It has been found that the new forging method and die when used with inverse draft at critical and useful points, results in a precision forging notobtainable under present practices in the forging industry. The new method can be used in drop hammer forging, press forging and upsetter forging equipment and it has been found that die life is not adversely affected. It can also be used in the cold forging process under certain conditions of material and analysis of the part to be forged. The inverse draft forging process can also be used at lower temperatures than used normally, even down to cold forging at room temperatures. It can also be used in forging materials other than steel and its alloys such as aluminum, brass, copper, Berryllium copper and other non-ferrous metals or materials.

It is therefore a general object of this invention to provide an improvement in forged tools and machine parts in which components forming grooves and tongues are formed integrally in the working member with a continuous uncut and uninterrupted grain flow extending longitudinally of the working member.

It is another object of this invention to provide forging tools and machine parts using a pivot mechanism in the form of an arcuate tongue and groove in which an inverse draft angle is used and the parts are formed without machining.

It is a further object of this invention to provide structure which may be formed with a negative and positive draft angle in combination when forging tools and machine parts.

It is still another object of the present invention to provide a method of forging machine tools and parts using a negative draft angle and a larger positive draft angle to form the parts while working a hot metal blank with a continuous uncut and uninterrupted grain flow.

It is another object of this invention to provide dies for forging tools and machine parts in which a negative draft angle in combination with a positive draft angle may be formed in at least one of the die members to form a part having a continuous uncut and uninterrupted grain flow extending through the part being formed.

These and other objects and advantages of the invention will more fully appear from the following description, made in connection with the accompanying drawings, wherein like reference characters refer to the same or similar parts throughout the several views and in which:

FIG. 1 is a plan view of a hand tool using a pivotal locking mechanism which may be made in accordance with the teachings of this invention; I

FIG. 2 is a section taken along lines 2-2 of FIG. 1 showing a tongue member of one handle member which is adapted to slide within a groove in the other member;

FIG' 3 is a section taken along lines 33 of FIG. 1 which illustrates the negative and positive draft angles of the other member of the hand tool;

, FIG. 4 is an elevation view of a machine part such as a ratchet formed according to the teaching of this invention;

FIG. 5 is a top plan view of the structure showing in FIG. 4;

FIGS. 6a, 6b, 6c are top plan views of different forms of machine holding dogs formed according to the teaching of this invention;

FIGS. 7a, 7b, and 7c are elevation views of the same dogs shown in FIGS. 60, 6b and 6c.

FIG. 8 is a section ofa pair ofdie members forming a die to forge a tool member having a plurality of grooves; and

FIG. 9 is a section of a pair of members forming a die for forging a tongue member.

FIGS. 1 through 3 show the basic form of a hand tool having a first handle member 10 and a second handle member 11. Handle member 10 has ajaw 12 formed at the extreme end thereof and handle :member 11 has another jaw member 13 formed atthe end thereof. The handles and jaws of the tool form the working members of the improved tool. Set off at an angle, is an intermediate portion 14 of the hand tool which extends between handle and jaw member 12. The intermediate portion 14 has a plurality of grooves 15 formed therein. The grooves have a substantially flat portion at the bottom thereof which may generally be termed a land portion 16. An elongated slot 17 is formed longitudinally of the intermediate member 14 in such a manner that a bolt 20 may ride in the slot, the bolt having a pair of flat edges that ride in slot 17. A bore is formed in handle member 11 and bolt 20 passes therethrough with a nut 21 being secured to bolt 20. Handle member 11 has a tongue 22 which is best shown in FIG. 2. It will also be noted that the tongue is formed with a negative draft angle on one side thereof and a positive draft angle formed on the other side thereof, the sides being separated by a narrow band 23. In each instance, it will be i seen that the negative draft angle is approximately 5 whereas the positive draft angle is substantially more than 5.

Tongue 22 may be pivotally rotated about bolt 20 so that handle member 11 may be slid in the slot 17 and thus engage any of the selected grooves 15. The groove and tongue negative draft angles are equal and thus a pivot mechanism is formed in which the members work in a sliding relationship.

Using only a forging process, results in eliminating any machining operations in the formation of the grooves 15 and the tongue 22. Therefore, through the use of a process of forging which needs no further machining for the tongue and grooves, it will be found that the working members are formed with a continuous uncut and uninterrupted grain flow which extends longitudinally of each of the working members.

In forging a hot metal blank, the blank is first heated to approximately 2,250 Fahrenheit. The hot metal blank is placed in the dies, such as the sections shown in FIGS. 8 and 9 and the dies are brought together to form the pieces such as found in FIGS. 2 and 3. In FIG. 8, a first die member 25 is shown having a substantially smooth and continuous work face cavity for engaging a metal blank 26. Another die member 27 is used with die member 25 which has a work face cavity for engaging the metal blank which has a plurality of grooves formed in confronting relationship with the first die member. Die member 27 has one side or edge 28 of the groove forming a positive draft angle of more than 5, for example, 8. The other side of the groove 29 has a negative draft angle of approximately 5, the portion between grooves sides or edges being designated a land portion 30. A parting line 32 is shown forming the line alongwhich die members 25 an 27 are brought together.

FIG. 9 is representative of a pair of

die members

35 and 37 with a hot metal blank 36 formed between the die members. Die member 35 has a substantially .smooth and continuous work face cavity for engaging a metal blank 36 and die member 37 has a work face cavity for engaging the metal blank which has at least one groove formed therein in which the groove contains a negative draft angle on one edge of a groove 39 with a larger positive draft angle on the other side 38. A land portion 40 is formed between the sides of the groove. The positive draft angle again is substantially more than 5 degrees and the negative draft angle is 5".

FIGS.- 4 and 5 demonstrate what may be achieved through the use of the inverse draft angle forging by producing a ratchet member 41. The ratchet member will boviously be stronger because there will be no machining required to produce the part that is generally undercut by machining to achieve the teeth in the ratchet member. Not only is the member stronger, but the machining process has been eliminated and thus in all of the tools and machine parts produced under the teaching of this invention, machining may be eliminated. Greater accuracy and uniformity per part is ob tained by forming numerous pieces from the same die impression.

FIGS. 6 and 7 show other forms of a holding dog in which FIGS. 6a and 7a demonstrate a member having a square face whereas FIGS. 6b and 7b demonstrate a holding dog with the member having a chisel or triangular face. FIGS. and 7c demonstrate the use of a holding dog having a curved face similar to the type shown in FIGS. 1 through 3. In each of FIGS. 6 through 7, it will be noted that there is no machining required to produce the inverse draft angle on the member As indicated previously, the steps in producing the finished tool are:

A. Forging a hot metal blank having a temperature of 2,250 Fahrenheit;

B. Annealling the pieces which are produced;

C. Heat treatment and finishing of the tool or part.

It will be noted that there is no machining require on the pivotal portion of the tool such as shown in FIG. 1, that is, with the grooves and tongue. By eliminating the machining operation, such as counterboring member 11 at the single tongue 22 to get a proper radius and angle to match the grooves, a more costly operation is eliminated and-due to the hard surface maintained by the heat treatment process, the grooves and tongue are more likely to resist wear and abrasion than a tongue and groove arrangement which is machined.

From the description presented herein, it will be seen that the instant invention provides an improvement in the formation of machine parts and hand tools by eliminating a costly machining operation which tends to weaken forged members. The teaching herein provides a means of forging a member in such a manner that there is a continuous uncut and uninterrupted grain flow of the metal while being worked in the dies. Thus, using dies with a negative draft angle and a greater positive draft angle, in the method set forth herein, produces an improved product of the dies.

It will of course, be understood that various changes may be made in the form, details, arrangement and proportions of the parts without departing from the scope of the invention which consists of the matter shown and described herein and set forth in the appended claims.

What is claimed is:

1. An improvement in forged tools and machine parts including a pair of cooperating working members having a holding mechanism holding the pair of working members in operable relationship and including at least first and second components formed on the pair of working members, the components comprising:

a. at least one groove constructed with a negative draft angle on one side thereof and a larger positive draft angle on the other side thereof separated by a land portion, said groove being formed integrally in the first working member with a continuous uncut and uninterrupted grain flow extending longitu'dinally of the first working member; and

b. at least one tongue constructed with a negative draft angle on one side thereof and a larger positive draft angle on the other side thereof separated by a narrow band, said groove and tongue negative draft angles being equal, said tongue being formed integrally in the second working member with a continuous uncut and uninterrupted grain flow extending longitudinally of the second working member.

2. The structure as set forth in claim 1 including:

0. a pivot mechanism having a plurality of said grooves, each formed in arcuate shape in the first working member, and having at least one tongue formed in arcuate shape in the second working member and fitting in sliding relationship into selected grooves of said plurality in the first working member.

3. The structure as set forth in claim 2 wherein:

said positive draft angle is substantially greater than said negative draft angle.

4. The structure as set forth in claim 3 wherein said negative draft angle is substantially 5.

5. An improvement in the method of forging tools and machine parts from blanks of hot metal having a pair of cooperating working members held in operable relationship with a holding mechanism, one working member including at least one groove formed integrally therewith and the other working member including at least one tongue formed integrally therewith wherein the movement between the dies therefore is in one plane only, the improved method comprising:

a. forging the hot metal blank with a continuous uncut and uninterrupted grain flow extending longitudinally of the one working member while forging all grooves with a negative draft angle on one side thereof, a larger positive draft angle on the other side thereof, and with a land portion between the sides of said groove; and

b. forging another hot metal blank with a continuous uncut and uninterrupted grain flow extending longitudinally of the other working member while forging the tongue with a negative draft angle on one side thereof, a larger positive draft angle on the other side thereof, and with a narrow band between the sides of the tongue.

6. The improved method of forging set forth in claim 5 wherein said positive draft angle is substantially greater than said negative draft angle.

7. The improved method of forging set forth in claim 5 wherein said negative draft angle is maintained at substantially 5.

8. An improvement in forging dies for forging tools and machine parts from metal blanks having working members including at least one tongue or groove integrally formed therewith, said dies comprising:

a. a first die member having a substantially smooth and continuous work face cavity for engaging a metal blank;

b. a second die member having a work face cavity for engaging a metal blank with at least one groove formed therein in confronting relationship with said first die member, said groove having a negative draft angle on one side thereof and a larger positive draft angle on the otherside thereof separated by a land portion, said first and second die members forming a parting line disposed no greater distance from said first die member than the depth of said groove.

9. The structure as set forth in claim 8 wherein:

10. The structure as set forth in claim 9 wherein said negative draft angle is substantially 5.

Claims

1. An improvement in forged tools and machine parts including a pair of cooperating working members having a holding mechanism holding the pair of working members in operable relationship and including at least first and second components formed on the pair of working members, the components comprising: a. at least one groove constructed with a negative draft angle on one side thereof and a larger positive draft angle on the other side thereof separated by a land portion, said groove being formed integrally in the first working member with a continuous uncut and uninterrupted grain flow extending longitudinally of the first working member; and b. at least one tongue constructed with a negative draft angle on one side thereof and a larger positive draft angle on the other side thereof separated by a narrow band, said groove and tongue negative draft angles being equal, said tongue being formed integrally in the second working member with a continuous uncut and uninterrupted grain flow extending longitudinally of the second working member.

2. The structure as set forth in claim 1 including: c. a pivot mechanism having a plurality of said grooves, each formed in arcuate shape in the first working member, and having at least one tongue formed in arcuate shape in the second working member and fitting in sliding relationship into selected grooves of said plurality in the first working member.

3. The structure as set forth in claim 2 wherein: said positive draft angle is substantially greater than said negative draft angle.

4. The structure as set forth in claim 3 wherein said negative draft angle is substantially 5*.

5. An improvement in the method of forging tools and machine parts from blanks of hot metal having a pair of cooperating working members held in operable relationship with a holding mechanism, one working member including aT least one groove formed integrally therewith and the other working member including at least one tongue formed integrally therewith wherein the movement between the dies therefore is in one plane only, the improved method comprising: a. forging the hot metal blank with a continuous uncut and uninterrupted grain flow extending longitudinally of the one working member while forging all grooves with a negative draft angle on one side thereof, a larger positive draft angle on the other side thereof, and with a land portion between the sides of said groove; and b. forging another hot metal blank with a continuous uncut and uninterrupted grain flow extending longitudinally of the other working member while forging the tongue with a negative draft angle on one side thereof, a larger positive draft angle on the other side thereof, and with a narrow band between the sides of the tongue.

7. The improved method of forging set forth in claim 5 wherein said negative draft angle is maintained at substantially 5*.

8. An improvement in forging dies for forging tools and machine parts from metal blanks having working members including at least one tongue or groove integrally formed therewith, said dies comprising: a. a first die member having a substantially smooth and continuous work face cavity for engaging a metal blank; b. a second die member having a work face cavity for engaging a metal blank with at least one groove formed therein in confronting relationship with said first die member, said groove having a negative draft angle on one side thereof and a larger positive draft angle on the otherside thereof separated by a land portion, said first and second die members forming a parting line disposed no greater distance from said first die member than the depth of said groove.

9. The structure as set forth in claim 8 wherein: said positive draft angle is substantially greater than said negative draft angle.

10. The structure as set forth in claim 9 wherein said negative draft angle is substantially 5*.