US2875650A

US2875650A - Double end forming, drilling, etc., machine

Info

Publication number: US2875650A
Application number: US476810A
Authority: US
Inventors: Hazlinger John
Original assignee: Individual
Current assignee: Individual
Priority date: 1954-12-21
Filing date: 1954-12-21
Publication date: 1959-03-03
Anticipated expiration: 1976-03-03

Description

March 3, 1959 J}. HAZLINGER 2,875,650

DOUBLE END FORMING, DRILLING, ETC. MACHINE Filed Dec. 21, 1954 9 Sheets-Sheet 1 INVENTOR JOHN HAZLINGER avg/5" 062 ATTORNEY March 3, 1959 J. HAZLINGER 2,875,650

DOUBLE END FORMING, DRILLING, ETC. MACHINE Filed Dec. 21, 1954 9 Sheets-Sheet 2 INVENTOR H JOHN HAZLINGER ATTORNEY MACHINE March 3, 1959 J. HAZLINGER DOUBLE END FORMING DRILLING, ETC

9 Sheets-Sheet 3" Filed Dec. 21, 1954 INVENTOR JOHN HAZLINGER ATTORNEY .1. HAZLINGER DOUBLE END FORMING, DRILLING, .ETC.

Filed Dec. 21, 1954 March 3, 1959 MACHINE 9 Sheets-Sheet. 4

INVENTOR JOHN HAZLJNGER BY/SMW ATTORNEY March 3, 1959 J. HAZLINGER 2,875,650

DOUBLE END FORMING,\DRILLING, ETC.) MACHINE Filed Dec. 21, 1954 9 sheets-sheet 5 J II v 42 64 7 v %I 97 73A 95A 0 60A I 56 F v 65 INVENTOR JOHN I-IAZLINGER' ATTORNEY MACHINE March 3, 1959 J. HAZLINGER DOUBLE END FORMING, DRILLING, ETC.

9 Sheets-Sheet 6 Filed Dec. 21, 1954 INVENTOR JOHN HAZLINGER March 3, 1959 J. HAZLINGER 2,375,650

DOUBLE END FORMING, DRILLING, ETC. MACHINE 9 Sheets-Sheet '7 Filed Dec; 21, 1954 INVENTOR JOHN HAZLINGER QmhudEXw m OM29 vUOFm OMPQQEPME IEO ATTORNEY 2,875,650 DOUBLE- END FORMING, DRILLING, ETCW MACHINE J. HAZLINGER March 3, 1959 Filed Dec. 21, 1954 9 Sheets-Sheet 8 I25 I26 I24 I23 INVENTOR HO" JOHN HASLINGER BY fiam 0m ATTORNEY .Magch 43, 1 959 J. HAZIJINGER 2,875,650

DOUBLE END FORMING, DRILLINCi, ETC. MACHINE 'Filed Dec. 2-1, 1954 .9 Sheefcs- Sheet 9 l g l i W Ill 1 l INVENTOR 14 ,JOHN HAZLINGER ATTORNEY United States Patent DOUBLE END FORMING, DRILLING, ETC., MACHINE John Hazlinger, Bound Brook, N. J.

Application December 21, 1954, Serial No. 476,810

9 Claims. (CI. 77-21) This invention relates to a machine for performing double end operations on work in a continuous manner.

The principal object of the invention is to provide a machine whereby work pieces, pre-cut to desired length and requiring tool operations, such as drilling, forming, threading, or the like, at both ends thereof, may be successively delivered automatically to work carriers, wherein they are automatically clamped and firmly held intermediate the ends thereof during the cycle of the tool operation thereon, and wherein upon completion of the cycle, the work pieces are automatically released in succession from the work carrier and ejected from the machine during continued movement of the carrier in unison with the working tools, thus providing for continuous operation simultaneously at each end of the Work pieces as they are successively fed to and discharged from the machine.

Another object of the invention is to provide a machine as above described, further characterized by its extreme simplicity of design, the ready accessibility of its parts and its adaptability for use on work of various lengths.

Another object of the invention is to provide a machine of this character which, when once set to perform the desired operations upon the work, will not require indexing for accurately performing the desired operations.

Still another object of the invention is to provide a machine of this general character, wherein the movement of the tools into engagement with the work is effected by mechanism operating to exert pressure on the quills directly in alignment with the axial center of the spindle, thereby reducing strain and wear to a minimum.

Still another object is to provide an improved form of collet or locking mechanism for effectively securing the work pieces to the work carrier, and means which are synchronized with longitudinal movement of the tools into and out of engagement with the work, for actuating and tie-actuating the collet or locking mechamsm.

The foregoing and other objects of the invention, and the advantages thereof, will be more readily apparent to those skilled in the art from the detailed description of the several embodiments given below and from the accompanying drawings, in which:

Fig. 1 is a view in side elevation of a machine embodying the invention;

Figs. 2 and 3 are views in elevation, taken at opposite ends thereof;

Fig. 4 is a view partly-in cross-section and partly in elevation taken along line 4-4 of Fig. 2 in the direction indicated by the arrows;

Figs. 5 and 6 are similar views taken, respectively, along lines 5-5 and 6-6 of Fig. 4 in the direction indicated by the arrows therein;

Fig. 7 is a similar view taken along line 7-7 of Fig. 4, looking in theropposite direction; 1

2,875,650 Patented Mar. 3, 1 959 ice Figs. 8 and 9 are fragmentary views on a somewhat larger scale, of certain of the parts shown in Fig. 7, in several positions thereof;

Fig. 10 is a view in end elevation, on an enlarged scale of collet mechanism illustrated in Figs. 8 and 9;

Fig. 11 is a view of the same in side elevation;

Fig. 12 is a view taken along line 12-12 of Fig. 10;

Fig. 13 is a plan view of the same, taken along line 13-13 of Fig. 11; i

Fig. 14 is a cross-sectional view taken along line 14-14 of Fig. 13;

Fig. 15 is a generated view illustrating in plan the action of mechanism employed for effecting longitudinal reciprocating movement of the tool spindles in operation of the machine;

Fig. 16 is a similar view illustrating the action of mechanism employed for operating the collet mechanism of Figs. 10 to 14;

Fig. 17 is a view similar to Fig. 7, showing a modified form of mechanism for locking the work pieces in the work carrier;

Fig. 18 is a top plan view thereof;

Fig. 19 is an enlarged fragmentary view of the mechanism shown in Fig. 18; and

Fig. 20 is a view in cross-section taken along line 20-20 of Fig. 19.

The particular embodiment. of the invention illustrated in the drawings is a machine for drilling both ends of each work piece. It will be understood that the nature of the work, such as forming, threading, or the like operation, performed by the tools at either or both ends, may be varied to suit the requirements of the particular job. Further, although the work pieces shown are in the form of bar stock, they may also be in the form of tubular stock, in Whole or in part.

Referring particularly to Figs. 1 to 4, the numeral 2 indicates a support or bed frame of suitable construction on which are mounted the working parts of the machine. In brief, these comprise essentially a pair of longitudinally spaced housings for rotary spindle carriers, a work carrier positioned intermediate the housings, means for automatically feeding the work thereto, locking it therein, and ejecting it therefrom, and the drive and actuating means therefor.

The housings 3, 3A are adjustable longitudinally with respect to one another. Thus, the housing 3A may be bolted to the frame as indicated at 8, and the other housing 3 is made slidably movable longitudinally with respect to the housing 3A, to accommodate the machine to work of various lengths, as by an internally threaded boss 9 on the under face of housing 3 and extending downwardly into the bed frame for engagement with a threaded rod 10 extending through the end wall 11 of the.

bed and operated by a hand wheel 12 fixed thereto.

A pair of opposed spindle carriers, indicated by the

numerals

13, 13A are mounted for rotary movement in the housings 3, 3A, respectively. In the particular embodiment illustrated, the spindle carriers are each arranged to accommodate a series of eight

spindle housings

15, 15A, respectively, disposed in turret fashion about the common axis of rotary movement of the carriers.

Each of the spindle housings is made of a tubular portion or quill 17 having ball races 17a, and slidable longitudinally in the carriers. The portions 17 are each in telescoping engagement with a separate portion 18 enlarged as at 19 and having the opposite end thereof externally threaded as indicated at 20 for engagement with the spindle adjusting assembly comprising a cap 21, an adjusting nut'22 and a threaded bolt 23. Each of the caps 21 is formed at the outer end thereof with a longitudinally extending ear 24 to receive and support the 3 bearingpin of camrollers 26, 26A disposed in alignment with the associated spindles.

Fastened to the interior of the end walls 30 of the housings 3, 3A, as by means of bolts 31, are annular collars 32,32A. These collars have their inner or radial edges formed to provide

cam surfaces

33, 33A, respectively, for coaction with the cam rollers 26, 26A, whereby to impart'longitudinal reciprocating motion to the spindle housings during rotary movement of the spindle carriers.

Confining rings

34, 34A may be bolted as indicated at 35, to the respective collars 32, 32A.

Desirably, retraction of the spindle housings from their ,fully extended positions in engagement with the work may be ensured by the provision of springs 36 interposed between the spindle carrier heads and the portions19 of the spindle housings, and normally urging the spindle housings to retracted position.

The

spindle shafts

37, 37A are each provided with a gear 38 fixed thereto, driven as will hereinafter be described. The outer end Walls 30 of the housings 3, 3A are formed with a central hollow hub 39 coaxial with the spindle carriers, to receive the bearings of hollow stub shafts 40, 40A, the inner ends of the shafts being provided with gears 41, 41A meshing with the gears 38. Thus, rotation of the shafts 40, 40A will effect rotation of the

spindles

37, 37A, respectively.

The

spindle carriers

13, 13A are bored centrally thereof to receive a shaft 42 extending longitudinally of the machine and journaled in bearings 43 supported in brackets 44 fixed adjacent the ends of the bed 2. The spindle carriers are each keyed to shaft 42, and as Will be seen, referring particularly to Fig. 4, the shaft extends freely through the hollow shafts 40, 40A.

The shafts 40, 40A may be driven as by means of belt pulleys 45, 45A through

speed reducers

46, 46A driven by

belt pulleys

47, 47A from

motors

48, 48A. Thus, the

spindles

37, 37A may be driven at desired rotational speed for performing the necessary operations upon the work.

Rotary motion of the

spindle carriers

13, 13A is enacted throughrotation of the shaft 42 from any suitable source of power, as from motor 50, driving a pulley 51 connected by belts 52 to a pulley 53 mounted on the shaft 42.

As will now be seen, rotation of the

spindle carriers

13, 13A with shaft 42 will bring about longitudinal reciprocating motion of each of the spindles and the tools carried therein, as a result of the coaction between the stationary cam surfaces 33, 33A and the cam rollers 26, 26A carried by the

spindle housings

15, 15A, respectively.

In accordance with the invention also, a work carrier 54 is positioned on the shaft 42 to rotate in unison with the

spindle carriers

13, 13A, and is constructed and arranged in its operation to automatically receive work pieces, indicated by the letter W, in rapid succession from a feed chute 55 and to discharge the finished pieces to a discharge chute 56. Referring particularly to Figs. 7 to 9, these chutes are supported on brackets 57 fastened to one side of the bed 2, so as to be inclined at opposite angles with respect to the horizontal axis of the machine. Preferably, the chutes will extend at an angle of approximtaely 45 degrees to one another.

The vertical side walls of the chutes are preferably adjustable relative to one another to accommodate work pieces of different lengths. The inner edges of the bottoms of the chutes are positioned in close proximity to the peripheral path of rotation of the work carrier, and the bottom of the feed chute 55 is formed with a pair of spaced, upwardly curved fingers or stops 55a, extending inwardly of said path. Thus, when the chute 55 is loaded with work pieces, the leading piece may come to rest on the peripheral surface of the work carrier, as shown, for example, in Fig. 8, or on the stop fingers 55a as shown in Fig. 7. Rotation of the work carrier in the direction indicated by the arrow in the latter figure will cause each leading work piece in succession to be picked off from the feed chute and to be received by the work carrier, where it is clamped intermediate its ends by mechanism hereinafter described, and thereby firmly held in position for performing thereon the necessary operations before it is released for ejection from the carrier at the discharge chute 56.

The work carrier, in a preferred embodiment of the invention, comprises a pair of spaced, centrally

bored plates

58, 58A mounted on the shaft 42 and keyed thereto as indicated at 59.

The

plate

58, 58A are formed along their peripheries with equally spaced recesses 60, 60A corresponding in number to the number of spindles carried by each of the spindle carriers. As will be seen particularly from Figs. 10 to 14, these recesses are bored axially of the plates to receive collet chucks 61, 61A, which may be fastened therein by any conventional means.

The arcuate length of the recesses at the periphery of the plates will be sufficient for easy clearance by the maximum diameter of the work pieces W. The collet chucks are of tapered wall thickness axially thereof, having the interior surfaces 62, 62A of frusto-conical shape from a maximum dimension at the inner side of the plates to a minimum at the outer side thereof. At the lower end of each chuck, a pin 63 extends radially inward from vits inner surface, substantially midway the axial length of the chuck.

Cooperating with each chuck is a pair of axially tapered

collet segments

64, 65, their direction of taper being reverse to that of the chucks, with circular inner surfaces 66, and frusto-conical outer surfaces 67 conforming to the inner surface of the chucks.

The opposed inner longitudinal edges of the chuck segments comprise inner portions 69 normally in sub stantially abutting relation and outer offset portions 70 parallel thereto, and respectively connected by angular portions 71, as more clearly shown in Fig. 13.

In normal retracted position of the collet segments (Fig. 12), the pin 63 will be freely accommodated in the space between the two edge portions 70. However, upon sliding movement of the segments inwardly with respect to their chucks, the angular portions 71 thereof riding the pin 63 will impart upward circular motion to the segments, causing them to close around a work piece W, and hold it firmly in position therein.

To actuate each pair of collet segments, yokes 73, 73A are positioned adjacent the innerface of the

plates

58, 58A for pivotal movement with respect thereto. Thus, a bolt 74 threaded into the

plates

58, 58A may have its head inserted in an elongated opening 75 of the yoke and provided with an opening 76 to receive a hinge pin 77 inserted in aligned holes 78 bored in the arms of the yoke.

The upper ends of the yokes are bored at 79 to be substantially concentric with the inner surface of the collet segments and each arm of the yoke is formed with a detent or projection 80 spaced from the face 81 of the yoke. The detents 80 are received in annular grooves 83 formed on the outer surfaces of the collet segments, the flanges 85 of the segments being received in the spaces 86 of the yoke arms.

As will now be seen, rocking motion of the yoke from a position such as shown in Fig. 12 to that of Fig. 11 will effect longitudinal movement of the collet segments and at the same time the action of the pin 63 on the inclined edges 71 will effect slight rotary movement of the segments in a direction to cause them to embrace and close around the work piece in a tight grip. Conversely, movement of the yoke 'in the opposite direction will slidably retract the collet segments from the collet chucks and at the same time cause them to rotate in a direction to unlock their grip upon the work piece. To retain the collet segments in position in their chucks,

and to ensure their return to normal position upon retraction from the chucks, a coil spring 87 encircles the chucks and has one end thereof fixed to the upper edge of segment 64 and its other end fixed to the upper edge of segment 65. The outer surface of the chuck is preferably recessed as at 89, 90 to confine the spring adjacent the outer surface of the

carrier plates

58, 58A.

To impart rocking motion to the yokes 73, 73A, the latter are machined at their lower end to receive a cam roller 92. These cam rollers are received for movement in a

cam groove

93, 93A formed on

circular plates

95, 95A which are bored centrally thereof to be fitted loosely on the shaft 42.

Plates

95, 95A are positioned on the shaft interiorly of the

carrier plates

58, 58A, respectively, as more clearly shown in Fig. 4 and are made stationary by means of arms 96 extending radially therefrom and fastened to bars 97 connected to the housings 3, 3A or to brackets on the bed frame. The arms 96, as will be noted particularly from Fig. 7, are both disposed between the feed chute 55 and the delivery chute 56, and hence out of the path of movement of work pieces supported in the work holders during operation.

Desirably, in order to provide for adjustment of the moment of impact of the yokes upon the collet segments, the yokes may have each arm thereof drilled and tapped to receive adjusting screws 98.

Referring particularly to Figs. 7, 15 and 16, the cam surfaces 33, 33A controlling the reciprocal motion of the

spindle shafts

37, 37A, respectively, are formed so that during the rotational movement of the spindle carriers 13,

13A, the spindles will be extended axially into engagement with the successive work pieces when the cam rollers ascend the portions of the earns 33, 33A represented by the inclined line 100 in Fig. 15, until the tools reach their maximum depth in the work, whereupon the tools will be retracted as these cam rollers descend the portions of the respective cam surfaces 33, 33A represented by the inclined line 101 in this figure.

Synchronized with this action of the cam surfaces 33, 33A is that of the

cam grooves

93, 93A (Fig. 16). As will there be seen, these cam surfaces are arranged so that during the time interval of engagement of the work by the tools, the cam followers 92 will ride the surfaces of these cam grooves represented by the horizontal line 102, retaining the yokes 73, 73A in position (Fig. 11) to cause the collet segments to remain in positions for firmly gripping the work piece (Fig. 14). Substantially at the moment the tools are completely retracted from the work piece at both ends thereof, the cam followers 92 ascend relatively steeply inclined portions of the

cams

93, 93A represented by the line 103 in Fig. 16, thereby causing the yokes 73, 73A to be rapidly rocked from a position as indicated in Fig. 11 to a position indicated in t Fig. 12. This action of the

cams

93, 93A causes the collet segments to be moved rapidly to the work-releasing position substantially at the moment the longitudinal axis of the work has arrived at the bottom of the discharge chute 56, so that it can be delivered thereto by gravity. t t t The spindle retracting action ofthe

cams

33, 33A will usually be initiated as each successive work piece reaches approximately the position indicated at F in Fig. 7, and

well in advance of its arrival at the discharge chute 56, and will be assisted by the action of the springs 36.

The tool spindles remain retracted during that portion of the circular path of the spindle carriers during which the cam rollers 26, 26A ride the portions of the

cams

33, 33A represented by the horizontalline 104 inFig. 15. The cam rollers 92, after ascending the portions of

cams

93, 93A represented by line 103 will traverse the portions thereof represented by the line 105 from themoment the collets have released their grip on the work piece until the work holder has received from the delivery chute 55 another work piece. Substantially immediately thereupon and before the

cams

33, 33A (portions represented by line cause the associated tool spindles to start forward towards the work piece, the cam rollers 92 descend the sharply inclined portions of the

cam grooves

93, 93A represented by the line 106 and thereby rapidly actuate the collets, as above described, to effectively grip the work piece.

In Figs. 17 to 20, there is shown a modified form of work holder and mechanism for clamping the work pieces therein. This modification may be used in lieu of the collet and its actuating mechanism above described for clamping the work in the work carrier intermediate the ings 113. The bushing seats of plate 110 are in axial' alignment with those on plate 111, and the bushings may be secured to the plates as by screws 114. Adjacent and to the rear of each of the seats (when viewed in the direction of rotation indicated by the arrow in Fig. 17) the carrier plates are drilled and tapped to receive, respectively,

studs

116, 117. The

studs

116, 117 are provided with collars 119, serving as bearing surfaces for clamping

dogs

120, 121. These latter are in relatively loose-fitting engagement with their respective studs, being normally held against rotation thereon by the action of a coil spring 123 interposed between an inner retainer 124 and an outer retainer 125 held in place by nut 126 threaded on the outer ends of the studs.

Adjustably mounted adjacent the work carrier, in any convenient fashion, as on bars 130, fixed to the frame, so as to be in the path of movement of the

dogs

120, 121, respectively, immediately beyond the feed chute 55, are trip pins 132. These pins are positioned so that on striking the leading edges 134, the clamping dogs will pivot on their studs 116 in clock-wise direction and the dogs 121 will pivot on their studs 117 in counter clock-wise direction, to engage the surface of the work piece.

Fig. 19 shows, in dotted lines, the position of one of the clamps 121 before striking a pin in its path of movement, and in full lines, its position after passing beyond the pin and in which its lower surface has engaged the work piece.

As will be understood, during rotation of the work carrier with shaft 42 in the direction indicated by the arrow in Fig. 17, succeeding ones of the workpieces will be received in the bushings 113and will be locked or clamped therein, in like manner, the work pieces being thereby firmly held in position, until released immediately before arrival at the discharge chute 56. To release the grip of the clamps upon the work, pins 136 similar to pins 132 are positioned in the path of movement of the tail portion 138 of the respective clamps, immediately before they arrive at the chute 56. On striking the pins 136 at their re-entrant edges 140, the clamping dogs are rotated on their respective studs 116, in counter clockwise and clock-wise directions, respectively, and forced to positions enabling the work pieces to be released from the bushings and to drop into the discharge chute upon reaching the mouth of the chute. i

As will be apparent, the interior size and shape of the bushings 113 constituting the work holders will depend upon the size and cross-sectional configuration of the work pieces to be operated upon, and the

clamps

120, 121 may readily be adjusted according to such size and configuration of the work pieces by screwing the

studs

116, 117 the required distance into the carrier plates.

In the work-clamping position of the clamping

dogs

120, 121, normal variations in thecross-sectional dimension of the Work pieces will be compensated by the action of the springs 123.

Having described my invention, what I claim is:

1. In a machine of the character described, a work holder comprising a collet chuck and a pair of collet segments fitted therein, the inner surface of said chuck and the outer surface of said segments being provided with means for causing one of the segments to rotate clockwise and the other of the segments to rotate counterclockwise for gripping the work when the segments are moved axially in one direction with respect to the chuck and for causing them to rotate respectively in opposite directions for releasing the work when moved axially in the opposite direction with respect to the chuck, and

means for effecting said axial movements of the segments.

2. A work holder comprising a collet chuck having an interior frusto-conical surface, a pair of collet segments having exterior frusto-conical surfaces, and means for moving said segments axially of said chuck, said chuck and segments having coacting means to impart slight rotary motion to said segments during axial movement thereof with respect to the chuck.

3. A machine of the character described, comprising in combination, a rotatable shaft, a pair of opposed tool spindle carriers mounted on said shaft for rotation therewith, a work carrier positioned on said shaft intermediate said spindle carriers and rotatable in unison therewith, a series of equi-spaced seats recessed in the periphery of said Work carrier, work-clamping means comprising collet segments positioned in each of said seats, a

work feed chute mounted adjacent the path of movement of said work carrier and having its feed end positioned for feeding work pieces in succession from said chute to said work-clamping means in a direction transverse to the axis of rotation of the work carrier, cam means positioned adjacent said work carrier and means actuated by said cam means for actuating said collet segments to and from work clamping position.

4. A machine of the character described, comprising in combination, a rotatable shaft, a pair of opposed spindle carriers mounted on said shaft for rotation therewith and each having a series of tool spindles arranged in planetary relation to said shaft, means rotatable independently of the rotation of said shaft for driving said spindles, a work carrier mounted on said shaft intermediate said spindle carriers and rotatable in unison therewith, said Work carrier having a plurality of seats formed in the periphery thereof, cam means positioned adjacent the outer ends of the spindles for reciprocating the same axially toward and away from the work carrier, a work feed chute positioned adjacent said work carrier for successively delivering work pieces to said seats of the work carrier in a direction transverse to the axis of rotation of the work carrier, collet segments positioned in each of said seats, cam means positioned adjacent the work carrier, and means actuated by said last-named cam means to reciprocate said segments longitudinally and axially to and from work clamping position.

5. A machine of the character described, comprising in combination, a rotatable shaft, a pair of opposed tool spindle carriers mounted on said shaft for rotation therewith, a work carrier mounted on said shaft intermediate said spindle carriers and rotatable in unison with said 1 spindle carriers, a work feed chute inclined downwardly toward said work carrier and positioned with its lower end adjacent the path of movement of said work carrier,

said work carrier having a plurality of seats formed in the periphery thereof, collet segments positioned in each of said seats and arranged to receive a work piece directly from said chute during movement of said seat past said end of the chute, spindles mounted in said spindle carriers coaxially with said seats, means for imparting reciprocal motion to said spindles, and means synchronized with the reciprocating movement of said spindles for actuating said collet segments in each of said seats successively during rotation of said work carrier and said spindle carriers.

6. A machine of the character described, comprising in combination, a rotatable shaft, a pair of opposed tool spindle carriers mounted on said shaft ror rotation therewith, a work carrier mounted on said shaft intermediate said spindle carriers and rotatable in unison with said spindle carriers, a work feed chute inclined downwardly toward said carrier and positioned with its lower end adjacent the path of movement of said work carrier, a work discharge chute inclined downwardly away from said work carrier, and positioned with its upper end adjacent the path of movement of said work carrier, said work carrier having a plurality of seats formed in the periphery thereof to receive work pieces directly from said work feed chute as the seats pass the lower end thereof and to discharge the work pieces directly to said discharge chute as the seats pass the upper end thereof, spindles mounted in each of said tool carriers coaxially with said work holders, means for imparting reciprocal motion to said spindles, and means synchronized with the reciprocating movement of said spindles for clamping the work pieces in each of said seats successively during its movement past the lower end of the said feed chute and for unclamping the work pieces in each of said seats successively substantially atthe moment the seats arrive at the upper end of said discharge chute.

7. A machine as defined in claim 6, wherein said clamping means comprises cam actuated members positioned in each of said seats, said members being each reciprocable axially and rotatable concentrically of said seats.

8. In a machine of the character described, a work carrier comprising a pair of spaced rotatable plates, each of said plates having a plurality of Work-recelving seats recessed in the periphery thereof, the seats of one plate being axially aligned with the seats of the other plate, a pair of collet segments mounted in each of said seats, a work feed chute mounted adjacent the peripheral path of the carrier and arranged to drop work pieces successively into each axially aligned pair of said seats, and means carried by each of said plates for imparting c rcular motion clockwise and counter-clockwise to each of said pairs of collet segments for actuating said segments to and from work-clamping positions.

9. In a machine as defined in claim 8, wherein said means comprises cam operated yoke members pivoted to each of said plates.

References Cited in the file of this patent UNITED STATES PATENTS 1,021,242 Fishburne Mar. 26, 1912 1,398,226 Fretter Nov. 29, 1921 1,666,732 Brophy Apr. '17, 1928 1,704,080 Davis Mar. 5, 1929 FOREIGN PATENTS 723,489 France Jan. 18, 1932