Search Images Maps Play YouTube News Gmail Drive More »
Sign in
Screen reader users: click this link for accessible mode. Accessible mode has the same essential features but works better with your reader.

Patents

  1. Advanced Patent Search
Publication numberUS3628359 A
Publication typeGrant
Publication dateDec 21, 1971
Filing dateJun 6, 1969
Priority dateJun 6, 1969
Publication numberUS 3628359 A, US 3628359A, US-A-3628359, US3628359 A, US3628359A
InventorsTlaker Erich
Original AssigneeFellows Gear Shaper Co
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Forming tool
US 3628359 A
Abstract  available in
Images(1)
Previous page
Next page
Claims  available in
Description  (OCR text may contain errors)

United States Patent {72] Inventor ErichTlaker Springfield, Vt. [211 Appl.No. 831,133 [22] Filed June 6, 1969 [45] Patented Dec.2l,197l [73] Assignee The Fellows Gear Shaper Company Springfield, Vt.

[54] FORMING TOOL 7 Claims, 5 Drawing Figs.

[52] U.S.Cl 72/76,

' 72/467 [51] lnt.Cl.....; B21] 13/02 {50] Field olSearch 72/77, 102, 103,467,468, 1 18,76, 121, 88, 89,90; 29/1592 [56] References Cited UNITED STA-TBS PATENTS 985.905 3/1911 Johnston 29/l59.2 2.375.481 5/1945 Lee eta1.... 72/88 2,906,143 9/1959 Musser 29/1592 3.025.946 3/1962 Raydtet al.... 72/467 3.396.563 8/1968 Tlaker 72/118 FOREIGN PATENTS 321,017 10/1929 Great Britain Primary Examiner-Richard .I. Herbst Att0rney-Cushman, Darby & Cushman method of cold-forming a profiled workpiece through radial material flow is disclosed wherein the flex ring has an internal profile complementary to the profile of the finished workpiece and wherein the lands of the flex ring forming profiles have uniform, relatively narrow widths from the minimum depth leading ends to the maximum depth trailing ends of the profiles while the widths of the forming profiles at a given radial distance from the center of theflex ring gradually increases from their leading to their trailing ends. The flex ring is deflected inwardly to penetrate the workpiece blank as the workpiece is fed therethrough with the feed of the workpiece and the flexing of the ring by the apparatus being coordinated so that the workpiece is progressively formed into the desired profile by the straining of localized circumferential areas of the workpiece and the resulting radial material flow in the workpiece blank.

FORMING TQOlL BRIEF DESCRIPTION OF THE INVENTION The present invention relates to flex ring forming tools for forming externally profiled workpieces and, in particular, to flex ring forming tools wherein the forming profiles of the flex ring are shaped to inhibit any longitudinal flow of the workpiece material and obtain formation of the workpiece by primarily radial flow of the workpiece material.

' Flex ring forming tools heretofore utilized in the cold-forming field have employed forming profiles wherein the lands of the forming profiles are greatest in width at the entrance of the flex ring with the lands decreasing in width from the entrance of the flex ring to the exit of the'flex ring as the profiles progress from minimum depth to full depth. In addition to the above, the widths of the forming profiles for a given radial distance from the axial centerlines of these tools remain constant or substantially constant throughout the length of the profiles.

.One method of forming such flex rings is to first machine an internally profiled part and subsequently machine a conelike entrance section into it. As a workpiece is fed into one of the prior art flex rings, substantially all of the forming action is produced by the lands or tips of forming profiles. The reason for this is the constant of substantially constant transverse cross-sectional width of the forming profiles, at a given radial distance from the center of the workpiece, from the entrance to the exit of the flex ring and the relatively wide contact areas of the forming profile lands which have their maximum width at the point of first contact with the workpiece. The above, in conjunction with the relatively narrow spaces between adjacent profile lands, causes substantial straining of the entire core of the workpiece when the workpiece is being formed and inhibits radial outward flow of the workpiece material thereby resulting in a progressive reduction of the entire cross section of the workpiece along with a corresponding elongation of the workpiece. As a result of this extruding action, the formed part is usually smaller in its exterior dimensions than the blanks from which it is formed. Furthermore, it has been found that it is usually not possible to produce well-defined teeth or toothlike profiles, using this type of flex ring, even when starting with blanks of a larger diametrical dimension than the intended dimension of the finished product.

The flex ring of the present invention solves the above-mentioned problems by restricting the straining of the workpiece blank to localized areas at the periphery of the workpiece blank thereby producing material flow only in such localized areas, while the core of the workpiece blank remains undeformed. By avoiding the straining of the entire cross section of the workpiece blank to such an extent that material flow would occur throughout the entire cross section of the workpiece blank, the lengthwise extrusion of the workpiece blank experienced heretofore is prevented. The resulting finished workpiece has external dimensions substantially the same as the original dimensions of the workpiece blank and the teeth or profiles of the blank are accurately formed.

A preferred form of carrying out the principles of the present invention utilizes a flex ring forming tool that has an internally profiled shape which is the counterpart or the complement of the shape of the finished workpiece. The flex ring has forming profiles with relatively narrow tips or lands of uniform width from the entrance of the flex ring where the forming profiles are of minimum depth to the full depth of the forming profiles at the exit portion of the flex ring. The widths of the forming profiles gradually increase, for a given radial distance from the axial centerline of the flex ring, from the leading ends of the forming profiles until the profiles reach full depth. With this construction, forming action takes place not only on the forming profile lands but also on the profile flanks or sides. The relatively narrow widths of the forming profile lands together with relatively large spaces between the adjacent profile lands and flanks, which define the areas of contact between the flex ring and workpiece blank, promote localized material flow radially outward into the space between the forming profiles and inhibit longitudinal flow of the workpiece material.

Since the width of the forming profile lands remain uniform and the widths of the profiles at a given radial distance from the flex ring axial centerline, increase gradually, a progressive displacement of the workpiece material takes place in localized peripheral areas adjacent the forming profile lands and flanks as the workpiece blank is penetrated. This forming action leads to a gradual squeezing or pinching of the workpiece blank material in the spaces intermediate the forming profiles and aids in the displacement of the material radially outward into the spaces of the flex ring between the forming profiles. Since the core of the material remains unstrained, the material deformed by the forming profiles of the flex ring moves radially outward and the cross section of the formed part measures essentially the same as the original cross section of the work piece blank. Primarily, only the shape of the finished work piece differs from that of the workpiece blank.

The flex ring forming tool of the present invention can be used to form a workpiece by the method and in the apparatus disclosed in my US. Pat. No. 3,396,563, issued Aug. 13, I968 and titled Method Of Forming Profiled Objects" and the entire disclosure of this patent is hereby incorporated into the present application by reference. Accordingly, the workpiece is cold-formed in a continuous process as it is fed through the flex ring by the application of forces through the flex ring to the workpiece in limited circumferential zones of the workpiece while moving the zones relatively circumferentially of the workpiece.

The above objects and advantages of the present invention will become more apparent and other objects and advantages of the present invention will become apparent from the following detailed description when taken in conjunction with the accompanying drawings in which:

FIG. 1 is a longitudinal section of the flex forming tool showing a workpiece about to enter the working portion of the flex ring;

FIG. 1A is a partial section at A-A of FIG. 1 showing only a portion of the flex ring;

FIG. '18 is a partial section at B-B of FIG. 1 showing only a portion of the Hex ring; 7

FIG. 1C is a partial section at CC of FIG. 1 showing only a portion of the flex ring;

FIG. 1D is an enlarged partial section at D--D of FIG. I diagrammatically illustrating the fiex ring with a formed workpiece therein and also illustratingin broken lines the shape of the flex ring profile comparatively at A-A, B-B, and C-C of FIG. ll;

FIG. 2 is a partial section of a machine which can be used with the flex ring forming tool of the present invention; and

FIG. 3 is an enlarged and exaggerated partial view showing the forming tool as it is flexed to form the desired profile in the workpiece when in a forming machine such as that illustrated in FIG. 2.

DETAILED DESCRIPTION OF THE INVENTION As shown in FIG. 1 and 1A through ID, the flex ring forming'tool has a plurality of profiles 22'which are complemental to the shape given to the workpiece W. For the purposes of illustration, the formation of a gearlike workpiece with axially extending teeth T is depicted. However, if other types of externally profiled workpieces are desired, such as workpiece with helical gear teeth or helically disposed elements, it is merely necessary to have the corresponding forming profiles on the flex ring similarly helically disposed and the desired shape will be obtained on the workpiece since the flex ring produces a finished workpiece which is its complement or counterpart.

The flex ring forming tool 20 is made of a suitable metal that is capable of being elastically deformed, such as by the application of forces thereto in limited zones spaced circumferentially about the flex ring. The forming profiles 22 of the flex ring extend radially inward from the inner surface of the flex ring with the depth of the profiles progressively increasing from the leading end or entrance 24 of the flex ring where the raw workpiece enters to a point (section c-c) intermediate the entrance and the trailing end or exit 26 of the flex ring from which the finished workpiece exits.

From their minimum to their maximum depth and throughout the entire length of the forming profiles 22, the forming profile tips or lands 28 have uniform or constant widths, X, which are relatively narrow when compared to either the spacing between adjacent profiles of the widths of the full depth portions of the profiles at their base. As best shown in FIG. 1D for any given radial distance from the axial centerline of the flex ring, the widths of the forming profiles gradually increase from their leading ends to the point C-C where they reach full depth. For example, the width of the profile at the radial distance R changes from X at A-A to Y at D-D.

The substantially constant .widths of lands 28, as compared with the gradually increasing widths of the forming profiles for a given radius can also be seen by comparing FIGS. 1A to IC.

At AA in FIG. IA, the profiles 22 of the flex ring 20 are of comparatively little depth with the relative widths of the profile lands 28, as compared with the spacing between the lands 28 and the side walls 30 of adjacent profiles, being relatively narrow. At B-B in FIG. 1B, the profiles have progressively deepened with the lands remaining the same or substantially the same width while the spacing between the sidewalls of adjacent profiles has become narrower. At C-C of FIG. 1C, the profiles 22 have reached the full depth of the profile to be formed on the workpiece 'and this cross-sectional configuration of the fonning profiles continues to the exit of the tool. The lands 28 are of substantially the same width as at section AA. However, it is to be noted that the width of the profiles for a given radial distance from the centerline of the flex ring has increased to its maximum width thereby farther decreasing the spacing between the sidewalls 30 of adjacent profiles for a given radius.

FIGS. 2 and 3 illustrate one type of apparatus with which the flex ring forming tool 20 of the present invention can be used to produce externally profiled workpieces by material flow of displacement.

Two or more rolls 2 and 3 act on the circumference of the flex ring 20 to deflect the ring inwardly to apply pressure to the workpiece W. These rolls 2 and 3 are carried on slides 4 and 5 which are fed inwardly by any appropriate means as is well known in the art, such as feed screws or hydraulic means if desired.

As shown in FIG. 2, the rolls 2 and 3 are mounted in bearings 6, 7, 8, and 9 which are carried in slides 4 and 5. The rolls 2 and 3 are free to rotate in these bearings upon contact with the workpiece W.

The flex ring 20 is held against axial movement relative to rolls 2 and 3 by a thrust member 10 acting through member 11 against the end 26 of the flex ring 20.

The member 10 acts against thrust bearing 12 and is rotatable in radial bearings 13 and 14.

The workpiece W is fed into and rotated by any suitable mechanism. As shown in FIG. 2, this consists of a work driver 15 which forces the workpiece W into the flex ring while simultaneously rotating the workpiece. The rotation of the workpiece W causes the flex ring 20 to rotate and the rotation of the flex ring 20 causes the freely mounted rolls 2 and 3 to also rotate.

If desired, it should be apparent that instead of rotating the workpiece positively, one or both of the rolls 2 and 3 may be positively rotated in which case, the rolls impart rotation to the flex ring 20 and the workpiece W so as to obtain the desired deflection of the flex ring 20 in the necessary localized circumferentially displaced areas.

It will be apparent that as the flex ring 20 rotates between the rolls 2 and 3 adjacent areas of the outer circumference of the ring pass through the deflection area of the deflection rolls 2 and 3 and as these areas pass through the deflected zone pressure will be applied in limited zones to the workpiece W causing the material to flow radially outward to gradually conform the work to theinternal profile of the flex ring 20 as shown in FIG. 1D.

The radial outward flow of the material of the workpiece W will occur in the deflection zones and in these locations, the

workpiece will be flowed in a direction to conform to the profiles of the flex ring 20 and to be complemental to the flex ring 20. Flow will occur only where pressure is applied; that is, in the deflection zone.

The pressure applied by the rolls 2 and 3 to the flex ring 20 are sufficient in magnitude to exceed the yield strength of the workpiece material in the localized deflection zones and in localized areas and this causes a flow of plastic material which progresses in incremental steps both-circumferentially and axially as the workpiece is fed into the flex ring 20. This flow continues until the final finished profile is produced on the workpiece as shown in FIG. 1D whereby the peripheral shape of the workpiece has changed from its originally circular profile 32 to the complement of the flex ring profile having teeth T.

The incremental feeding is dependent upon the speed of rotation through the deflection zones and the amount of deflection of the flex ring 20. The application of force in localized deflection zones or areas of the flexring circumference together with the unique structure of the flex ring forming tool avoids stressing of the entire cross section of the workpiece thus allowing the workpiece material to flow radially outward as the axial feed and the rotation progress. In addition to ensuring a primarily radial configuration of the workpiece material, the unique configuration of the flex ring forming tool 20 of the present invention inhibits any longitudinal flow of the material.

FIG. 3 shows the formation of a workpiece in apparatus such as disclosed in FIG. 2. In FIG. 3, the deflection of the flex ring 20 is shown in greatly exaggerated form. It will be seen from this FIG. 3 that the material of the workpiece W is forced radially outward into the spaces of the portions of the flex ring 20 which are being forced inwardly by the pressure exerted radially inward by the force of the rolls 2 and 3 acting on the flex ring 20 in the localized pressure zones.

The accuracy of the flex ring 20 is directly reflected in the accuracy of the workpiece since the workpiece is the complement of the contour of the flex ring. Since no generating action is involved nor any conjugate action between workpiece and tool, the workpiece obtained by the present invention is a true complement or negative of the flex ring.

Moreover, due to the fact that the dimension X, as shown in FIGS. 1A through 1D, is constant throughout the axial length of the flex ring, the outside diameter of the workpiece tooth is rigidly controlled throughout the forming operation and no flaking or seaming will occur on the tip of the tooth due to any undesirable outward material flow.

While the preferred form of the invention has been shown and described, it is to be understood that all suitable modifications and equivalents may be resorted to which fall within the scope of the invention.

What is claimed is:

l. A forming tool for forming a profile on a workpiece comprising: a flexible element having an opening therein adapted to receive a workpiece to be fed axially relative to said opening, said opening being peripherally defined by a plurality of inwardly projecting and generally axially extending forming profiles, said forming profiles having inner .terminal lands of substantially constant widths.

2. The forming tool of claim 1 wherein said forming profiles have portions adapted to make initial contact with the workpiece and each of said forming profiles have a minimum depth at said portions.

3. The forming tool of claim 1 wherein said forming profiles have portions adapted to make initial contact with the workpiece and wherein, for a specified depth, said forming profiles have their minimum widths nearest said portions.

4. The forming tool of claim 1 wherein the axially extending forming profiles are substantially straight.

5. The forming tool of claim 1 wherein the axially extending forming profiles are helical.

6. The forming tool of claim 1 wherein said forming profiles have portions adapted to make initial contact with the workpiece, each of said forming profiles having a minimum depth at said portions and said forming profiles, for a specified depth, having their minimum widths nearest said portions.

7. A forming tool for forming a complementary profile on a workpiece comprising: a flexible element having first and second end faces, said element having an opening therein extending between said end faces and adapted to receive a workpiece to be fed axially relative to said opening, said opening being peripherally defined by a plurality of circumferentially spaced, and inwardly projecting forming profiles, said forming profiles extending in a generally axial direction and having leading end portions adjacent said first end face adapted to make initial contact with the workpiece, said forming profiles having inner terminal lands of substantially constant width, said forming profiles increasing in depth from said leading end portions to maximum depths intermediate said first and second end faces, and, for a given depth, said forming profiles increasing in width from said leading end portions to maximum widths intermediate said first and second end faces.

* i I! I i

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US985905 *Jul 12, 1909Mar 7, 1911Allen JohnstonMethod of making gearing.
US2375481 *Jan 17, 1942May 8, 1945Burndy Engineering Co IncMethod of manufacturing a connector tubular splice with worked inner serrations
US2906143 *Mar 21, 1955Sep 29, 1959United Shoe Machinery CorpStrain wave gearing
US3025946 *Dec 12, 1958Mar 20, 1962Heinz Hahne KarlProduction of electric cable sheaths
US3396563 *Oct 21, 1965Aug 13, 1968Fellows Gear Shaper CoMethod of forming profiled objects
GB321017A * Title not available
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US7097399Aug 20, 2004Aug 29, 2006Bourn & Koch, Inc.Cutting machine for gear shaping or the like
WO1998035769A1 *Feb 14, 1997Aug 20, 1998Werth Elmer DTooling and method for forming a container
Classifications
U.S. Classification72/95, 72/76, 72/467
International ClassificationB21J5/12, B21K1/30, B21K1/28, B21C23/10, B21C23/02, B21J13/02, B21J5/06
Cooperative ClassificationB21J13/02, B21K1/30, B21J5/12, B21C23/10
European ClassificationB21C23/10, B21J5/12, B21J13/02, B21K1/30
Legal Events
DateCodeEventDescription
Apr 5, 1990ASAssignment
Owner name: FELLOWS CORPORATION, A CORP. OF DELAWARE, VERMONT
Free format text: RELEASED BY SECURED PARTY;ASSIGNOR:MARINE MIDLAND BUSINESS LOANS, INC.;REEL/FRAME:005280/0147
Effective date: 19900322
Apr 5, 1990AS17Release by secured party
Owner name: FELLOWS CORPORATION, PRECISION DRIVE, NORTH SPRING
Effective date: 19900322
Owner name: MARINE MIDLAND BUSINESS LOANS, INC.
Oct 11, 1988ASAssignment
Owner name: MARINE MIDLAND BUSINESS LOANS, INC., P.O. BOX 1130
Free format text: SECURITY INTEREST;ASSIGNOR:CONGRESS FINANCIAL CORPORATION;REEL/FRAME:004962/0318
Effective date: 19880804
Owner name: MARINE MIDLAND BUSINESS LOANS, INC., MASSACHUSETTS
Oct 3, 1988ASAssignment
Owner name: MARINE MIDLAND BUSINESS LOANS, INC., P.O. BOX 1130
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST. SUBJECT TO AGREEMENT RECITED;ASSIGNOR:FELLOWS CORPORATION;REEL/FRAME:004996/0271
Effective date: 19880825
Oct 3, 1988AS02Assignment of assignor's interest
Owner name: FELLOWS CORPORATION
Owner name: MARINE MIDLAND BUSINESS LOANS, INC., P.O. BOX 1130
Effective date: 19880825
Feb 11, 1987AS06Security interest
Owner name: CONGRESS FINANCIAL CORPORATION, 1133 AVE. OF THE A
Effective date: 19870121
Owner name: FELLOWS CORPORATION, A DE. CORP.
Feb 11, 1987ASAssignment
Owner name: CONGRESS FINANCIAL CORPORATION, 1133 AVE. OF THE A
Free format text: SECURITY INTEREST;ASSIGNOR:FELLOWS CORPORATION, A DE. CORP.;REEL/FRAME:004688/0053
Effective date: 19870121
Owner name: CONGRESS FINANCIAL CORPORATION,NEW YORK
Free format text: SECURITY INTEREST;ASSIGNOR:FELLOWS CORPORATION;REEL/FRAME:004688/0053
Feb 6, 1987ASAssignment
Owner name: EMHART INDUSTRIES, INC., 426 COLT HIGHWAY, FARMING
Free format text: SECURITY INTEREST;ASSIGNOR:FELLOWS CORPORATION, A DE. CORP.;REEL/FRAME:004666/0943
Effective date: 19870121
Owner name: EMHART INDUSTRIES, INC.,CONNECTICUT