US3162089A

US3162089A - Gear broaching apparatus

Info

Publication number: US3162089A
Application number: US234952A
Authority: US
Inventors: Frank L Riggio; Alfred B Strempel
Original assignee: Giannini Controls Corp
Current assignee: Giannini Controls Corp
Priority date: 1962-11-02
Filing date: 1962-11-02
Publication date: 1964-12-22
Anticipated expiration: 1981-12-22

Description

22, 1964 F. L. RIGGIO ETAL 3,162,089

GEAR BROACHING APPARATUS Filed Nov. 2, 1962 4 Sheets-Sheet l 1964 F. L. RIGGIO ETAL 3,162,089 I GEAR BROACHING APPARATUS Filed Nov. 2, 1962 .4 Sheets-Sheet 2 ma/MM Dec. 22, 1964 F. L. RIGGIO ETAL GEAR BROACHING APPARATUS 4 Sheets-Sheet 3 Filed Nov. 2, 1962 /QAA/A .6. 3 66/0, 9 41 250 B. STREMQEL,

INVENTORS.

United States Patent 3,162,98? GEAR BRGACHlNG APPARATUS Frank L. Riggio, Essex, and Alfred B. Strempel, Deep River, onn., assignors to Giannini Controls Corporation, Duarte, Calif-Z, a corporation of New York Filed Nov. 2, 1962, Ser. No. 234,952 8 Claims. (Cl. 99-40) The present invention relates to improvements in sys terns for the production of such machine elements as gears, or, in fact, any disk-like or cylindric element whether or not having peripheral teeth or notches. An illustrative and presently preferred form of the invention will be described with reference to gear production, but, as will become apparent, the invention may be applied for production of any other disk-like or cylindric element.

A system according to the present invention produces finished gears, for example, by forcing blanks through a series of shaving or broaching dies, with the blanks held in pressurized sandwich fashion between a forcing head and a pressurized yielding shedder head. Held in such manner between two heads, with at least the forcing head accurately fitting the final finishing or polishing die, the formed gear then has no edge burrs and is uniformly finished across its periphery from edge to edge. The finished gear is then ejected from the finishing die preferably by reverse movement of the shedder head pushing the gear back to an open space where it may drop out, or be easily pushed out, after the forcing head has been backed off from the shedder head toward its initial position where it is in preparation to take the next blank.

Such charactenistics of the invention, along with others, will be best understood from the following detailed description of the preferred and illustrative embodiment shown in the accompanying drawings, in which:

FIG. 1 is a general and schematic plan of the mechanical parts of the system;

PEG. 2 is an enlarged plan section of the dies, the containing box, and forcing and shedder heads;

FIG. 3 is a cross-section on line 3-3 on PEG. 2;

FIG. 4 is a section on line 4--4 of FIG.,2, and showing a typical blank feeder;

FlGS. 4a, 5, 6 and 7 are schematic enlarged fragmentary sections on lines da4a, 5--S, 66 and 7--7 on FIG. 2;

FIGS. 8, 9 and 10, are fragmentary sections in vertical axial planes showing several different operative positions of the blank and the forcing and shedder heads;

FIG. 11 is a partial section, in a vertical axial plane, illustrating a modification; and

FIG. 12 is a schematic illustrating automatic control of the several sequential operations.

As shown illustratively in the drawings an accurately formed box it) with bottom 22 (FIG. 3), side walls 24, and end walls 26, rigidly secured together (not shown), is mounted on a base 28 that in turn is mounted on the main base 3d (FIG. 1) of the mechanism. Box 20 is accurately dimensioned with flat faces of the bottom and sidewalls, to receive and accurately aline the several contained die, guide and spacer blocks. As shown illustratively here, a shaving or broaching die unit is preferably made up of an assembly of six

die blocks

49, 42, 44, 46, 43 and 59, accurately fitting the box, and lying between spacers 52, final shaving or polishing die block 54, spacer 56 and guide block 58 (at the left in FIG. 2), and guide block guide block 62, spacer 64 and guide block as (to the right in that figure). The whole assemblage of the elements just named fits the box interior for accurate alinement, and is held in tight face-to-face position by compressing screws 66. .The several blocks being accurately alined by the box, and their internal die and guide passages being accurately located in the same positions in the blocks, those die and guide passages are accurately alined. The spacer blocks 56 and 64, replaceable by others longer or shorter, provide for lesser or greater numbers of die

blocks

40, 42 etc. to suit the material of the blank being worked on, or the speed desired for forcing the blank through the several dies.

Each of the die blocks 40 to 54 has a central, internally toothed opening 8i) of the same outer diameter d, which is accurately the external diameter of the finished gear its teeth tip diameter. Those toothed die openings iii) are typically shown in FIGS. 4a, 5, 6, and 7, with internally projecting broaching or shaving teeth 82 projecting inwardly from that diameter in the die blocks ill to 5d, and polishing or shaving teeth 95 in the final die block '54. As indicated in FIGS. 2, 8, 9 and 10, the teeth in all the die blocks extend axially through the block thicknesses and, in blocks 49 to Sit may or may not have clearance from their initial cutting edges which are at the block faces to the right in FIG. 2. Finishing teeth 96 in block 54 are axially parallel with no clearance. Each block has at its left face a circular relief 83 of diameter greater than d, to take the shavings or polishings and to facilitate washing out by the fluid circulation used for that purpose.

As indicated in enlarged FIG. 4a, the internal tooth formation extends around the circular periphery of diameter d in each of thedie blocks. The fragmentary views in FIGS. 5, 6 and 7 are much enlarged in order to show clearly the progressive increase in tooth width and depth from die block 45), through the assemblage to die block 54. As typified in those figures, those broaching teeth 82 commencing with the teeth in block 4 (FIG. 4a) are relatively narrow as seen axially and project inwardly from diameter d only slightly, and then, through the series of dies to 59 (FIGS. 5 and 6), the teeth increase in width and projection until, at block 48 or 5% (FIG. 6), they are accurately of, or very close to, the shape and dimensions of the inter-teet-h spaces in the finished product. Then the polishing or shaving teeth 96 in final die 54 (PEG. 7) are of dimensions and shape to accurately and tightly fit the finished gear. It is noted that the broaching teeth operate only on the sides and roots of the gear teeth being formed; the tips of the forming gear teeth ride the bores at diameter d to accurately guide and center the blank. The several sets of broaching teeth are, of course, lined up axially with each other and with teeth 96 in final die 54.

Guide block 6%, lying immediately against the first die block 40, has, as shown in FIG. 3, an internal guide passage with internal gear teeth 86 that accurately fit the external gear teeth 88 of the forcing head 90 on the end of forcing mandrel 2. The diametral dimensions and tooth pitch and shape of head 99 are accurately the same as those of the finished gear, the same as the toothed internal die shape of final finishing die 54; and the external (teeth tip) diameter of 90, and also the tooth root diameter in die block 54 are accurately the same as diameter d of the circular die openings 8%) in die

blocks

40, 42, etc. Forcing head 91 with its external teeth 88, is, as shown in FIG. 2, of such axial length as to remain in toothed engagement with the internally toothed guide block 60 when head 5% reaches the end of its stroke to the left (FIG. 9).

The internal die teeth as of final die b1ock 54 may typically be axially parallel without any cutting edge clearance. The broaching die teeth 82 of the several die locks 4t), 42 etc. may have the cutting edge clearance and relief that is common for broaching teeth. Those broaching teeth rough out the gear teeth on the blank forced through them, to configurations to tightly fit the toothed formation in final die 54, which shaves the entire periph- Patented Dec. 22, l fi l a") cry of the tooth with a very light cut, or substantially polishes the tooth surfaces.

FIGS. 2 and 8 show forcing head 90 in its position at the start of its forcing stroke to the left. Internal gear teeth 86 in guide block 60 extend substantially through the whole width of that block and guide forcing head 90 both axially and non-rotatively throughout its stroke to the left. All the broaching teeth 82 in the several die blocks, and the internal tooth formation 96 in finishing die block 54, are axially lined up with the guide teeth at 86 in guide block 60; so that, as forcing head 91) moves on its stroke to the left, guided by the internal bores 89 in the several die blocks, its tooth spacings will line up with the several sets of breaching and polishing teeth. It follows from the dimensions that have been described that forcing head 9% is accurately guided throughout its motion by engagement of the tips of its teeth, which have the diameter d, with theroot portions of the successive dies, all of which root portions have the common diameter d.

As forcing head 90 moves toward the left, a centering pilot pin 10f) projecting from its forward flat face 102, may enter in fairly close fit a central opening 104 in the blank 1% that has been introduced through the slot 1% in guide block 60. The blank drops down slot 108 until, resting on its bottom 110, its 'centralopening 14% is sub stantially in alinement with pilot pin 100. Then as face 162 of the forcing head 99 approaches the blank, pin 10%) may also enter, in close fit, the central bore 114 in the shedder head 116 which, on the inner end of shedder mandrel 118, then stands in such a position as shown in FIG. 2. Further forced movement of forcing head 0 to the left then clamps the blank between the two opposing flat faces of the two heads 9% and 116 as a sandwich (FIG. 8). Shedder head 115, as will be noted later, is under constant yielding pressure less than the pressure moving head 90 to the left, so the blank, as it is moved to the left through the several breaching dies, is held pressurably and flatly between the two heads. As shown in FIG. 4a, shedder 116 has substantially the same diameters and tooth configuration as presser head 90*, with its tooth spacings lined up with the broaching teeth 82 and. with the tooth formation 96 in the final die 54.

Instead of pin 100, head 90 may have a cupped end formation to receive the central projection on a hubbed blank, to center it. Or, in the case of a blank having a previously formed pinion aifixed to one face, pin 10% may enter a central opening in the pinion, or a cup on 913 may take a central pinion shaft or hub. The finally formed gear will then be accurately concentric with the pinion.

Forcible movement of blank 1% to the left'from the position of FIG. 8, presses its outer part againstthe shearing edge of toothed die opening 80in die block 40 and, between the broaching teeth, shears it accurately to an outer diameter d equal to that of the several die openings 86). At the same time the inter-tooth spaces begin to be broached out by the teeth 82 in 40 (FIG. 4a). Then, as the blank is moved on, it is kept centered and alined by its pressure holding between the two heads and by peripheral contact with the outer die diameter a; Its teeth spacings are step-by-step broached out by the progressively widening and deepending breaching teeth 82 until, on leaving the final die or dies 50, 48, its peripheral tooth formation is substantially the same as that of forcing head 530 and that of final die 54.

On leaving the final bro-aching die 50, the blank, sandwiched pressurably between the two heads, moves across the open space between die blocks and 54-the'space provided by the two spacers 52. During that movement shedder head 116 has enteredthe internal tooth formation 96 of final die 54, and presser head 99 is stillfin tooth registration with the internal teeth of guide block 60. The blank, held between the twoheads is thus lined up to enter the final internally toothed die 54. That die finishes the tooth formation on the blank, mainly by polishing action;

and, seeing that the forcing head fits the internal formation of die 54 very closely, any burrs that may have resulted from the actions of the other dies 50, 48 etc. are completely removed.

' Movement of the two heads, with the formed gear between them, stops in the position of FIG. 9. In that position, shedder head shoulders up, for instance against guide bushing 126i. Pressure on shedder head 116 is now relieved, so that, in the next ensuing movement of presser head 98 to the right and to or toward its original position of FIG. 2, head 116 does not immediately follow it, possibly pushing the finished gear 106a out of 54 in clamped engagement with the presser head. Pilot pin is withdrawn from the finished gear liloa, that gear being left against the shedder head as that gear then fits the internal configuration of die 54 quite tightly and pilot pin 160, though it may fit tightly in the gear aperture, is withdrawn relatively easily due to its smaller size.

After return movement of presser head 90 toward the right, the pressure is again applied to shedder shank 118 to move shedder head 116 and the finished gear 1666: to such a position as shown in FIG. 10 where the gear is in the open space between dies 56 and 54 and between spacers 52. There, the finished gear drops off as indicated in broken lines, and may then drop out of the whole machine through suitable passages. Shedder head 116 may be stopped momentarily in the position of FIG. 10 to insure the gear dropping oif before being possibly pushed against die 50. After the gear has dropped off, resumed or continuous pressure on 118 to the right then carries shedder head 116 back to its original position of FIG. 2 where it is stopped by some shouldering action, such for instance as the piston in the actuating cylinder of 118 coming up against a cylinder head. Presser head as has already reached the position of FIG. 2, ready for the next cycle of gear breaching action after a new blank has been dropped to the position of FIGS. 2 and 4.

FIG. 4 shows an illustrative blank feeder mounted on box 20 over the slot 108 in block 60. In the feeder a slot leads from a hopper which keeps that slot full of blanks. The preceding blank web in that line enters the vertical feeder slot 132 and is releasably held from dropping by a spring pressed ball 134. A plunger 136 with a piston head 138 in cylinder 14% is normally held up by spring 142. When hydraulic pressure under valve control is applied at 14 plunger 136 is forced down to press blank 10611 past the detent ball 134. The blank then drops down, as indicated, to the position shown in FIGS. 2 and 4, onto the slot bottom 110, ready for the ensuing cycle of gear formation.

The open space 520 (FIG. 10) through which the finished gear is delivered need not be immediately adjacent final die block 54. It may be located in any spacing between any two of the blocks. FIG. ll shows a modification in which the finished gear is finally delivered through a passage in the guide block (it. In this modification, as an example, the blank introduction slot 1% leads down through block 60 at a slight angle to the vertical, so that the blank 106, dropping down through that slot at that angle, finally comes to rest on the shelf 119a that forms the effective bottom of that slot. The pilot pin 100 in its then position may help guiding the blank to that position.

A delivery slot leads down from the bore in block 60 just to the right of shelf 110a. In this modification the open delivery space 52a between the two die

blocks

50 and 54 may be omitted. The finished gear will be carried back by the reversed movement of shedder head 116, through the several dies, until that head arrives in the position of FIGS. 2 and 11. There, especially by the stopping of head movement, the finished gear will be thrownrofi into such a position as shown at was where it will drop out through slot 156.

Operating shanks 92 and 118 are accurately centered and guided relative to the axis of the dies by bushings 129 in guide blocks 58 and 66 and in final die block 54. The operating hydraulic cylinders and their connected mechanical elements for controlled operation are schematically shown in FIG. 1.

In that figure the die box 2% is shown mounted on the main base 30 on which are mounted the operating cylinders 166 and 162 for the presser and shedder shanks 92 and 118. Solenoid valve 164 controls admission of hydraulic pressure fluid to the outer end of the smaller shedder cylinder 162, and two such valves 166 and 168 control fluid admission to the inner and outer ends of the larger presser cylinder 160. Another solenoid valve 170 is shown on the feeder 172 to control admission of hydraulic fluid to its cylinder. In an automatically controlled system, circuit controlling switches are carried at 176 on the main base and are actuated to closed and opened positions by settable members 178 on slide rods 180 that are connected by arms 182 with the presser and shedder shanks 92 and 118 to move with them.

The sequential operations of the system may be either manually or automatically controlled. In either case the sequence is as follows. Valve 170 is first momentarily opened to operate the feeder to deliver a blank to the position of FIG. 2. Valve 164 will be open to apply hydraulic pressure to the piston in the smaller cylinder 162 to hold its piston 163 up against its cylinder head and hold shedder head 116 yieldably in the position of FIG. 2. After the blank has reached its position of FIG. 2, valve 168 on the larger cylinder 160 will be opened to apply hydraulic pressure to its piston to force the presser head 90 and shedder head 116, with the blank sandwiched between them, through the dies to the position of FIG. 9. Valve 164 on the shedder cylinder 162 may then be closed, and then, with valve 1&8 on the presser cylinder 160 simultaneously closed to hydraulic pressure but opened to exhaust, valve 165 will be opened to apply pressure to the piston 161 in cylinder 16% to move presser head 91) back to the right until it comes to a stop in the position of FIG. 2. After presser head 91) has withdrawn its pilot pin 1% from the finished gear, then valve 164 will be opened to press the shedder head back toward and to the position of FIG. 2, dropping the finished gear at the space 52a, or other similar space, or at the starting position shown in FIG. 11. If the gear ;is delivered at such a spacing as 52a, valve 164 may be momentarily closed to stop the shedder head long enough in that position (FIG. to insure the gear dropping free.

FIG. 12 shows schematically an illustrative semiautomatic control system in which the start of a cycle is controlled manually. In a full automatic system that initiation and all subsequent sequential operations would be automatically controlled.

In FIG. 12, assume that the several solenoid valves are closed to pressure and valves 16:? and 168 opened to exhaust when their solenoids are de-energized; and the several valves opened to pressure when their solenoids are energized.

A manual switch 21M) is thrown manually to apply current via 292 to solenoid valve 170 of the feeder. After feeding in a blank switch 2% is thrown over to apply current to 204 leading through switch 212 to valve 168, and to 295 leading through switch 208 to shedder valve 164. The presser and shedder heads then move through their stroke to the extreme left hand position of FIG. 9. On reaching that position (for delivery of the formed gear at the delivery space 52a) switch 208 is, by actuation of the mechanism shown in FIG. 1, kicked over to its broken line position where it tie-energizes valve 164 and energizes line 210 leading to valve 165. At the same time, at the left hand end of the stroke, switch 212 has been kicked over to its broken line position to de-energize valve 168. With valve 165 open, the presser head now moves to the right to its original position. On reaching that position the mechanical connections kick switch 268 over to the full line position to again energize valve 1e:

and de-energize valve 166. The shedder head then moves to the right to its original position where it is held by the pressure applied by valve 164. To initiate the next cycle, when switch 200 is thrown to its broken line position, to again energize the system after a blank has been fed in, switch 212 is, at the same time, kicked over to its full line position to energize M8, either by mechanical connection with 2% or manually.

It will be noted that if the finished gear is finally delivered as in FIG. 11 at the initial position of the shedder head, that head need only be stopped in its return movement in that position while the presser head moves on away from it to the spaced initial position of the presser head. In general, wherever the delivery space is located, it is only necessary to stop the shedder head on or before reaching that space; and, in the delivery scheme of FIG. 11 where the shedder head is stopped by coming up against a physical stop to allow the presser head to move on away from it, the yielding hydraulic pressure on the shedder head may be continuous.

We claim:

1. A machine for breaching or shaving a peripheral surface of a blank to a predetermined size and shape, comprising the combination of a die unit with an axial opening provided with broaching edges adapted, on forcing a blank through the opening, to form the peripheral surface of the blank to approximately the predetermined size and shape,

a finishing die with an axial opening accurately corresponding to the predetermined size and shape and situated in axial alignment with the die unit at one axial end thereof,

a forcing head axially alined with the openings in the die unit and the finishing die and having a transverse working face of a size and shape accurately the same as the opening in the finishing die,

said forcing head having an initial position with the working face spacedly opposing the other end of the die unit and being movable in a forward stroke to move the working face through the die unit and into the finishing die,

means for positioning a blank in axial alinement upon the forcing head in intimate contact with the working face thereof,

guide means for positively and accurately guiding the forcing head during said forward stroke to enable the forcing head to enter the opening in the finishing die wherein its Working face fits accurately,

and means for driving the forcing head and the positioned blank axially from said initial position through the die unit and into the finishing die to form the peripheral surface of the blank accurately to the predetermined size and shape, any burrs formed on the blank by the broaching edges of the die unit being eliminated by virtue of the accurate fit of the Working face of the forcing head in the opening in the finishing die.

2. A machine for breaching or shaving a peripheral surfaceof a blank to a predetermined size and shape, comprising the combination of a die unit with an axial opening provided with broaching edges adapted, on forcing a blank through the opening, to form the peripheral surface of the blank to approximately the predetermined size and shape,

a finishing die with an axial opening accurately corresponding to the predetermined size and shape and situated in axial alinement with the die unit at one axial end thereof, 7 Y

a guide elementhaving an axial opening accurately corresponding in section to the opening of the finish ing die and situated in axial aiinement with the die unit at the other end thereof,

an axially alined forcing head having a transverse working face at its forward end,

said forcing head having an initial position with'the working face spacedly opposing the other end of the die unit, and being movable in a forward stroke from said initial position to move the working face through the die unit and into the finishing die,

said forcing head having a cross-section that extends effectively continuously and uniformly from the working face rearwardly for a length at least equal to the length of the said stroke plus at least a portion of the axial thickness of the guide element, and is of a size and shape to fit closely the openings in the guide element and in the finishing die, whereby the forcing head is positively guided both radially and rotationally throughout its stroke to maintain accurate alinement with the opening in the finishing die,

means for positioning a blank in axial alinernent upon the forcing head in intimate contact with the working face thereof,

and means for driving the forcing head in its forward stroke to move its working face and the positioned blank axially from said initial position through the die unit and into the finishing die to form the peripheral surface of the blank accurately to the predetermined size and shape, any burrs formed on the blank by the breaching edges of the die unit a being eliminated by virtue of the fit of the working face of the forcing head in the opening in the finishing die.

3. A machine for breaching or shaving a peripheral surface of a blank to a predetermined size and shape, comprising the combination of a die unit with an axial opening provided with broaching edges adapted, on forcing a blank through the opening, to form the peripheral surface of the blank to approximately the predetermined size and shape,

a finishing die with an axial opening accurately corresponding to the predetermined size and shape and situated in 'axial alinement with the die unit at one axial end thereof,

a guided forcing head axially alined with the openings in the die unit and the finishinig die and having a transverse working face of a size and shape to fit closely the opening in the finishing die,

said forcing head having an initial position with the working faw spacedly opposing the other end of the die unit and being movable in a forward stroke to move the Working face through the die unit and into the finishing die,

a guided shedder head axially alined with said die openings and axially reciprocable through the final die and into the die unit through said one end thereof, and having an initial position with one end spacedly opposing the working face of the forcing head in initial position thereof,

yielding means normally acting to move the shedder head through the said dies toward, and to hold it yieldingly in, its initial position,

means for positioning a blank in axial alinement between'the end of the shedder head and the working face of the forcing head in their initial positions,

and means for driving the forcing head in its forward stroke, thereby gripping the positioned blank between the end of the yielding shedder head and the Working face of the forcing head and moving the gripped blank through the die unit and into the finishing die, to form the, peripheral surface of the blank accurately to the predetermined size and shape, any burrs formed on'the blank" by the breaching edges of the die unit being eliminatedby virtue of the fit of the working face of the forcing head in the opening in the finishing die.

4. The combination defined in claim 3,

8 the driving means for the forcing head acting to termihate the forward stroke with the blank within the finishing die, said combination also including means for moving the forcing head on return movement out of the finishing die and through the die unit to its initial position,

return movement of the shedder head in response to said yielding means then ejecting the formed blank from the finishing die,

and means for retarding return movement of the shedder head toward its initial position to allow the forcing head on its return movement to move away from the shedder head to release the formed blank, there being a radially extending discharge aperture adapted for discharge of the released blank.

5. The combination defined in claim 4, and in which said discharge aperture is located between the finishing die and the die unit,

and said retarding means operates to retard the shedder head in the final die.

6. The combination defined in claim 4-, and in which said retarding means comprises means for stopping the movement of the shedder head by said yielding means in said initial position of the shedder head,

and said discharge aperture is located at said other end of the die unit between said initial position of the shedder head and said initial position of the forcing head.

7. A machine for breaching or shaving a peripheral surface of a blank to a predetermined size and shape, comprising the combination of a die unit with an axial opening provided with broaching edges adapted, on forcing a blank through the opening, to form the peripheral surface of the blank to approximately the predetermined size and shape,

a finishing die with an axial opening accurately corresponding to the predetermined size and shape and situated in axial alinement with the die unit at one axial end thereof,

a guided forcing head axially alined with the openings in the die unit and the finishing die and having a transverse working face,

said forcing head being reciprocable to move the working face in a forward stroke through said die unit from the other end thereof and into the finishing die,

a guided shedder head axially alined vn'th said die openings and axially opposing the working face of the forcing head,

yielding means normally acting to move the shedder head axially toward the forcing head,

means for positioning a blank in axial alinement between the end of the shedder head and the working face of the forcing head,

means for driving the forcing head in its forward stroke, thereby gripping the positioned blank between the end of the yieldingshedder head and the working face of the forcing head and moving the gripped blank through the die unit and into the finishing die to form the peripheral portion of the blank to the predetermined size and shape,

. interengageable elements on the forcing head and on the positioned blank adapted to be closely interengaged by the initial movement of the forcing head toward the blank to position the blank accurately with respect to the forcing head,

means for moving the forcing head on its return stroke,

means for'holding the shedder head in its position in the finishing die during at least a part of the return stroke of the forcing head, the formed blank fitting the finishing die in tight frictional engagement to cause release of said interengageable elements in response to said return movement of the forcing head,

and means acting, after completion of said part of the return stroke of the forcing head, to release the shedder head for movement toward the forcing head to eject the disengaged blank from the finishing die,

there being a radially extending discharge aperture 5 adapted for discharge of the released blank.

8. The combination defined in claim 7, and in Which said discharge aperture is located between the finishing die and the die unit,

and said part of the return stroke of the forcing head extends from the finishing die beyond the discharge aperture.

References (Iited in the file of this patent UNITED STATES PATENTS Blanchard Oct. 10, 1922 Smith Oct. 18, 1904 Russell Apr. 25, 1933 Russell Nov. 21, 1933 Hart Mar. 26, 1940 Hansen et a1. Apr. 8, 1941 Green Aug. 14, 1945 Green Feb. 8, 1949 Tozer Apr. 3, 1951

Claims

1. A MACHINE FOR BROACHING OR SHAVING A PERIPHERAL SURFACE OF A BLANK TO A PREDETERMINED SIZE AND SHAPE, COMPRISING THE COMBINATION OF A DIE UNIT WITH AN AXIAL OPENING PROVIDED WITH BROACHING EDGES ADAPTED, ON FORCING A BLANK THROUGH THE OPENING, TO FORM THE PERIPHERAL SURFACE OF THE BLANK TO APPROXIMATELY THE PREDETERMINED SIZE AND SHAPE, A FINISHING DIE WITH AN AXIAL OPENING ACCURATELY CORRESPONDING TO THE PREDETERMINED SIZE AND SHAPE AND SITUATED IN AXIAL ALIGNMENT WITH THE DIE UNIT AT ONE AXIAL END THEREOF, A FORCING HEAD AXIALLY ALINED WITH THE OPENINGS IN THE DIE UNIT AND THE FINISHING DIE AND HAVING A TRANSVERSE WORKING FACE OF A SIZE AND SHAPE ACCURATELY THE SAME AS THE OPENING IN THE FINISHING DIE, SAID FORCING HEAD HAVING AN INITIAL POSITION WITH THE WORKING FACE SPACEDLY OPPOSING THE OTHER END OF THE DIE UNIT AND BEING MOVABLE IN A FORWARD STROKE TO MOVE THE WORKING FACE THROUGH THE DIE UNIT AND INTO THE FINISHING DIE, MEANS FOR POSITIONING A BLANK IN AXIAL ALINEMENT UPON THE FORCING HEAD IN INTIMATE CONTACT WITH THE WORKING FACE THEREOF, GUIDE MEANS FOR POSITIVELY AND ACCURATELY GUIDING THE FORCING HEAD DURING SAID FORWARD STROKE TO ENABLE THE FORCING HEAD TO ENTER THE OPENING IN THE FINISHING DIE WHEREIN ITS WORKING FACE FITS ACCURATELY, AND MEANS FOR DRIVING THE FORCING HEAD AND THE POSITIONED BLANK AXIALLY FROM SAID INITIAL POSITION THROUGH THE DIE UNIT AND INTO THE FINISHING DIE TO FORM THE PERIPHERAL SURFACE OF THE BLANK ACCURATELY TO THE PREDETERMINED SIZE AND SHAPE, ANY BURRS FORMED ON THE BLANK BY THE BROACHING EDGES OF THE DIE UNIT BEING ELIMINATED BY VIRTUE OF THE ACCURATE FIT OF THE WORKING FACE OF THE FORCING HEAD IN THE OPENING IN THE FINISHING DIE.