US2209027A - Broaching machine - Google Patents

Description

July 23, 1940. KAPLAN ET AL BROACHING MACHINE Filed Au 25, 1938 3 Sheets-Sheet l Ennentors (Ittorneg July 23, 1940. p l. KAPLAN ET AL BROACHING MACHINE Filed Aug. 25, 1938 3 Sheets-Sheet 2 Zhwentofs Zea fffap n ,Zrar Gas/4f Von 71 6/15 8 g Qttorneg I uly 23, 1940- L. l. KAPLAN ET AL 2209,02?

BROACHING MACHINE Filed Aug. 25, 1938 3 Sheets-Sheet 3 IN VENTORS lea J: Keep/a? ATTOEY.

Patented July 23, 1940 UNiT n STATES,

BaoAcmNe MACHINE.

Leo I. Kaplan and Bror Gustaf von Reis, Detroit,

Mich, assignors to Detroit Broach Company, Detroit, Mich, a corporation of Michigan Application August 25, 1938, Serial No. 226,780

12 Claims.

This invention relates to broaches for cutting splines on a male shaft member and also to the fixtures for supporting the broaches on a broach machine.

An object of the invention is to provide means for broaching splines on the exterior of a shaft along the entire length thereof, the breaching operation constituting the only and, hence, the finishing operation in the formation of the splines.

It is also an object to provide meansv for breaching separated groups of splines in the exterior sides of a shaft of any shape in cross section alongthe entire length'thereof in one operation, the shaft blank having finished ground arcuate corners and/or a finished bore longitudinally thereof constituting locating means for the broaches.

More particularly it is an object to provide means for simultaneously broaching a plurality of sides of a shaft blank in such manner that peripherally separated groups of splines are formed thereon, the intervening spaces of the blank or the longitudinal bore being employed as locating means, and to'provide alternate forms of broach holders such that the locating means may be relatively movable or relatively fixed with respect to the blank.

Another object is to provide an improved tool holder or fixture to cut splines along thelength of a shaft characterized by means for holding the shaft blank from opposite sides while cutting two other sides and reciprocal on or with a broach machine table to and from cutting position, the holder positively holding the blank during cutting operations and automatically releasing its hold on the blank when the tool is retracted.

A further object is to provide means for positively holding a shaft blank, as above described, in combination with means for indexing said blank for cutting the remaining sides when the pressure on the first two sides is relieved.

Other objects and advantages will become more fully apparent as reference is had to the accompanying drawings wherein our invention is illustrated and in which:

Fig. 1 is a top plan view of our improved fixtures with a shaft blank inserted therein in position for the initial cutting operation, the breach machine slides being shown in section.

Fig. 2 is a view similar to'Fig. 1 showing also the broaches and completion of the first cutting operation, r i

Fig. 3 is a view similar to Figs. 1 and 2 showing completion of the second cutting operation;

Fig. 4 is a vertical section taken along the line 4-4 of Fig. 2;

Fig. 5 is a detail section taken along the line 5-+5 of Fig. 4;

Fig. 6 is a detail section taken on the line 6-6 of Fig. 1;

Fig. .7 is a top plan view of a modified form of tool holder and cutters,

Fig. 8 is a vertical section taken along the line 88 of Fig. 7 showing the cutters immediately above the blank, the blank being partially broken away;

Fig. 9 is an end elevation of the blank;

Fig. 10 is a vertical section of a modified fixture;

Figs. 11 and 12'are sections taken respectively on the lines ll-ll and l2-l2 of Fig. 10; and

Fig. 13 is a section, similar to Fig. 12, and illustrati'ng the work positioned for the second cutting operation.

More particularly l indicates a stationary table of a breaching machine upon which a work holding fixture platform 2 is slidably mounted. A work holding fixture is keyed at 4 to the platform 2, and is composed of a large block 3 having two work-holding rods 5 slidably mounted therein.

Each of the rods 5 has a work-gripping end 6 normal thereto for engaging a work piece I in order to hold the piece against an oppositelyplaced holding member 8 carried by the block 3. The two work holding means 6 and 8 thusgrip. the work piece, which in this instance is a shaft blank, along two oppositeside walls thereof. It is contemplated, in Fig. 4, that the broaches 9 will approach the work I from above and hence a base member I0 is also provided at the lower end of the work to oppose the thrust. of the broaches 9, this member I!) being supported on the lower one of the rods v5. The other ends of the rods 5 are pivotally connected, jointly, to a toggle device which consists of links I I each pivotally connected at one end to an arm 5 and each pivotally connected at [2 to a further link is which in turn is pivotally anchored at M to astandard l5 rigidly mounted on the machine I. The connections I2 are pivotally connected to links [6 which are mutually pivoted at IT, and between this connection I! and the standardl5 a spring I8 is inserted.

The operation is as followsfl the fixture 2, 3 is slid to the left, Fig. 4, for loading; the spring 18 reduces the angle between the arms l6 pull ing the connections I 2 toward each other to maintain pressure of the fingers G on the work until the fixture has travelled a considerable distance. Further retracting movement of the fixture is accompanied by sliding of the shafts 5 in the block 3 and consequent lateral separation of. the members 6 and 8. The work piece 1, being hollow, is then inserted between the members 6 and 8 and placed on the base in engagement with a tightlyfitting or expansion type extension IS integral with the base II]. The fixture is then traversed to the position illustrated in Fig. l,

whereupon the shafts 5 slide in the block 3, thus closing the members on the work while positioning the work immediately below the broaches 9. The broaches are then actuated through the work taking opposed cuts of tWO' groups of. splines 20, as illustrated in Fig. 2. The work is then indexed and the broaches take asecond cut of the re'- maining two surfaces, as illustrated in Fig. 3.

Any suitable indexing means may beemployed, one suitable type being illustrated in Figs. 4, v5 and6. The base It] is'mounted on a shaft 2| which is journalled in the lower rod 5. A ratchet gear 22 is fixed to the bottom 'of the shaft 2! for engagement by a spring pressed pawl 22a pivotally mounted on a. bracket BSwhich is fixedly mounted on a stationary part of the machine I. The pawl 22a. is placed so that it will rotate the base I B and work 'l -through ninety degrees as "the fixture approaches its retracted position. The work 1 does notshift laterally with respect to the clamping member 6 and hence the member 6 has a cut-out portion 24 formed on an arc of a circle having'the same radiusas that of the corners 25 and 26 ofthework piece.

The work piece is of generally rectangular shape in plan 'view, with the corners rounded andformed on'the arc of a common circle. The

four corners 25, 26, 2'! and Rare first ground to accurate shape, the intervening or' connecting surfaces 28, 30, 3! and 32 being flattened. Since thearcuate cornersarefinished ground before placement of thework piece in the broaching machine l, they are reliable" guide and locating means and are employed as such. The clamps 6 and 8 are provided with arcuate regions to receive these arcuate corners so that when the clamps are drawn together the broaches will then cut surfacesjhavingan exact and known relation with the corner surfaces. The shafts are then cut or broached'throughout their entire lengths and no further operation, such as hobbing, is necessary.

Figs. 1 to 5 illustrate clamps which are stationary, whereas Figs. -8 and 9 illustrate a base support for the work and guide; or locating surfaces which travel withthe broaches. The work blank 33'is placed on a support 34 analogous to the support" it, previously described. Four broaches 35 joined by corner pieces 36 are then clamped together ready for traversal through the work. The broaches. 35. ea'chhas a series of spline cutters thereon and these cutters are separated by the accurately formed arcuate surfaces '31 on the blocks at. As the'broaches'travel ove'r'and through thework the surfaces 31 closely fit the arcuate'surfaces 38 and constitute locating means to maintain correct relative posi tion of the broaches and the wor 'Inthe modified'fixture shown in Fig. 10, a stationary table 48 has awork holding fixture platform 4! slidably mounted thereon. A work holding fixture 42 is keyed'at 43 to the platform 4|, and has a'single' work holding rod 44 which is slidably mounted therein'-.- The slidable rod 44 has a work-gripping formation 45 for engaging a work piece 46 adjacent one end thereof, whereby the pressure of a spring 41, acting on toggle links 48, which are connected to the rod 44, causes the work-gripping formation 45 to hold the work piece 46 against an oppositely disposed Work holding member 59. i

As described in conjunction with Figs. 1 to 5, it is contemplated that the broaches will approachthe work from above, and the rod 44 is,

therefore, provided with a base member 49 at the lower end of the work to oppose the thrust of the broaches. The base member 49 is rotatable, and has a ratchet wheel 50 connected thereto and adapted to be rotated by a pawl as above described for indexing the work piece. The base member 49 has a tightly fitting or expan- 'sion type extension 49a extending into the lower end .of thework piece 46.

In the work fixture 42 is slidably mounted a pin 5|, accurately located with respect to the Work holding member 59, and adapted to project into the upper end of the work piece 46 to hold it against the work holding member 59. Linkage 52 is connected to the pin 5| for the purpose of retracting it from contact with the work piece, and for replacing it in contact with the work piece.

The work-gripping formation 45 and the work holding member 59 both have arcuate surfaces for engagingthe workpiece 46, which is of circular section. The work piece is finished ground before placement in the broaching-machine, and the broaches first cut the splines 53 indicated in dotted lines in Fig: 12 and full lines in Fig. 13. The work is then rotated through ninety degrees, after which the broaches cut the second series of splines shown in dotted lines in Fig. 13;

What is] claimed is:

1. A fixture for holding a work blank in a broaching machine having reciprocable broaches comprising a base reciprocable toward and away from the direction of travel of the broaches, a Work blank support on said fixture, work locating means for gripping the blank along the length thereof, and automatic means responsive to the movement of said base toward the line of travel of said broaches drawing said means together to impose substantial pressure on said blank during cutting travel of said broaches along said blank. 2; A fixture for holding a work blank in a broaching machine having reciprocable broaches comprising a base reciprocable toward and away from the direction of travel of the broaches, a work blank support on said fixture, work locating means for gripping the blank along the length thereof; and automatic means responsive to the movement of said base toward the line of travel of said broaches drawing said means together to imposesubstantial pressure on said blank during cutting travel of said broaches along said blank, said automatic means responding to withdrawal of said base from said line of travel to release the pressure of said locating means from said blank. v v

3. The combination of a broaching machine, an endwise support for a work blank on said machine, reciprocable broaches grouped for simultaneously taking a plurality of peripherally spaced cuts along the exterior of said blank, and non-cutting means separating said breaches and movable therewith and constituting guides for contacting said blank throughout the cutting operation along the spacesbetween said cuts.

" 4. The combination of'a broaching machine, an

endwise support for a work blank of generally rectangular transverse cross-section having rounded corners, broaches for simultaneously cutting splines in a plurality of the sides of the blank, and work locating means active along the length of said rounded corners retaining said blank in correct cutting position.

5. The combination of a broaching machine, an endwise support for a work blank of generally rectangular transverse cross-section having rounded corners, broaches for simultaneously cutting splines in all of the surfaces between said rounded corners, and work locating means movable with said broaches and contacting said rounded corners during the cutting operation.

6. The combination of a broaching machine having reciprocable broaches, a support for a Work blank on said machine, a plurality of guides peripherally spaced about said blank and residing along the sides thereof supporting said blank during the entire reciprocation of said broaches thereover, said guides gripping said work blank during travel of the broaches over said work, means releasing said guides from pressure contact with said blank, means indexing said blank after release of said guides and means automatically returning said guides to work gripping position after indexing 7. A fixture for holding a work blank in a broaching machine having reciprocable broaches comprising a base reciprocable toward and away from the direction of travel of the broaches, a work blank support on said fixture, work locating means for gripping the blank along the length thereof, automatic means responsive to the movement of said base toward the line of travel of said broaches drawing said means together to impose substantial pressure on said blank during cutting travel of said broaches along said blank, said automatic means responding to the withdrawal of said base from said line of travel to release the pressure of said locating means from said blank, indexing means operative to partially rotate said blank after the initial cutting operation by said broaches after the release of the pressure from said blank.

8. A fixture for holding a hollow work blank in a broaching machine having reciprocal broaches, comprising internal positioning abutments shaped to fit into and engage the internal surfaces at opposite ends of the work blank and to extend circumferentially around at least a major portion of such surfaces for contact with a mul tiplicity of diametrically opposed points, an abutment for engaging the work blank externally, and means for causing relative movement between at least one internal abutment and the external abutment whereby said abutments grip the work blank therebetween.

9. A fixture for holding a hollow work blank in a broaching machine comprising a base reciprocal toward and away from the broaches, a pair of oppositely disposed abutments for engaging and clamping one end of a work blank on said fixture, said abutments being movable toward and away from the work blank incident to movement of the base toward and away from the path of the broaches respectively whereby the abutments grip and release the work piece, and a movable abutment for engaging the work blank and adapted to hold the same in contact with one of said first two abutments during movement of the base.

10. A fixture for holding a work blankin a broaching machine comprising a base reciprocal toward and away from the path of travel of the broaches, means on said fixture for supporting a work blank for rotative movement about its longitudinal axis, automatic means for ro-tatively moving the work blank incident to movement of the fixture away from the path of the broaches, and means rendered operative by travel of the fixture toward the path of the broaches for clamping the work against rotative movement.

11. The combination of a broaching machine having a set of broaches relatively reciprocal with respect to a Work support, said work support having an abutment adapted to engage in one end of a work blank to position the blank with respect to the broaches, said set of broaches comprising circularly grouped units adapted to act on all sides of the blank simultaneously, and means for causing relative movement between the broaches and the support.

12. The combination of a broaching machine having. a set of broaches relatively reciprocal with respect to a work support, said Work support having an abutment adapted to engage in one end of a work blank to position the blank with respect to the broaches, said set of broaches comprising circularly grouped units adapted to act on all sides of the blank simultaneously and having guide means engaging the blank to hold the blank and broaches in predetermined position during relative movement between the broaches and the blank.

BROR GUSTAF VON REIS. LEO I. KAPLAN.

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