US2388064A - Thread grinder - Google Patents

Description

4(hatr 30, 1945.

A. F. MARKUS THREAD GRINDER 5 Sheets-Sheet 1 Filed June 29, 1944 6) 8 z m? P. il-

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THREAD GRINDER Filed June- 29, 1944 5 Sheets-Sheet 2 l m@ gm ww o. QQ

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5 Sheets-Sheet 3 QV Y 0t 30, 1945- A. F. MARKUS THREAD GRINDER Filed June 29, 1944 Oct. 30, 1945. AF, MARKUS Y 2,388,064

THREAD GRINDER Filed June 29, 1944 5sheets-sht 4 TTO m54? Oct. 30, 1945. A* F. MARKUS 2,388,054` I THREAD GRINDER Filed June 29, 1944 5 Sheets-Sheet E5" l usf War/Zad -r-ro Ptnmied oct. 3o, 19454 UNITED STATES PATENT \oFF1cE '4 2,388,064 THREAD GRINDER August F. Markus, Detroit, Mich., assignor to Ex- Cell-O Corporation, Detroit, Mich., a corporation of Michigan \k Application June 29, 1944, Serial No. 542,719

18 Claims.

The present invention pertains to a n vel machine for performing thread grinding operations.

Thegeneral aim of the present invention is to provide a thread grinder embodying a novel and simplified combination of elements such asv to adapt it `especially for production in small sizes while still incorporating various refinements necessary in producing high precision work, the resultantsimplication and minimization of size affording not only a low cost machine suited to the quantity production of high precision thread ground parts such as are used, for example, in aircraft, but also one which may be operated with facility by women in view of the small mus"- Fig. 2 is an enlarged fragmentary sectional i view taken from front to rear through the machine substantially along the line 2-2 in Fig. 1.

Fig. 3 is a longitudinal sectional view taken substantially along the line 3-3 in Fig. 2.

Fig. 4 is an enlarged detail sectional view taken substantially along the line 4 4 in Fig. 2.

Fig. 5 is a perspective view of the drive and operating connections for the work supported head, the latter being indicated partially in phantom by broken lines.

Fig. 6 is a fragmentary detail perspective view of the adjustable support for the grinding wheel included in the machine.

Fig. 7 ls a fragmentary front elevation of the work support and underlying intermediate supscribe in detail the preferred embodiment, but it is to be understood that I do not thereby intend to limit the invention to the specific form disclosed, but intend to cover all modifications and alternative constructions falling within the spirit and scope of the invention as expressed in the appended claims.

Referring more particularly to the drawings,

'the invention has been exemplified therein as embodied in a` `thread grinder especially adapted for speedy production of high precision thread ground parts. In Fig. 1, the illustrative machine there shown embodies a grinding Iwheel Ill mounted for rotation about an axis extending generally transversely of the machine and adapted to grind a work piece indicated at W in Fig. 3 and received between centers II arid I2 of headstock and tailstock I4 and I5, respectively, incorporated in a worl supporting head designated generally as I6. .Such head I6 is arranged in a manner hereinafter detailed to reciprocate to and fro past the grinding wheel I0 and also to pivot or rock toward and away from the latter about a horizontal axis generally parallelingthewheels axis of rotation. Reference is made to the axes as being generally" parallel since provision is made for adjustably skewing the `heel axis slightly out of exact parallelism with the work axis to accommodate various desired helix angles for the threads to be ground. As will appear hereinafter in connection with detailing of the various parts of the exemplary machine shown, provision is made for tilting the work relative tothe grinding wheel by several mechanisms and for various purposes, viz: (l) to effect incremental infeeding of the work for size control and to effect subsequent rapid retraction ofthe work, (2) to effect progressive motion of the work toward or from the wheel in timed relation with the work translation for taper grinding, and (3)` to effect periodic motion of the work toward and from the wheel in timed relation with the work rotation, or more often in timed relation with both the work rotation and translation, for use, for example, in relief grinding as in backing off" or relieving the teeth of thread cutting tools beingyground s'uch as taps or thread milling cutters. l,

Turning now to the'matter of the supporting arrangement for the head I6, the same comprises a guide bar of cylindrical exterior shape along which the head is adapted to slide while being I guide bar section II-is solid, being flxed lnped- The - I8 is tubular in form and is fixed intermediate its ends within a pedestal bracket 22 projecting upwardly from the machine base. The opposite or outer end of this guide bar section I8 is supported through the medium of a hollow shaft 23 which is journaled in it and is in turn journaled in a pedestal bracket 24 on the machine base `2I.

The work supporting head I6 itself comprises a main frame casting 25 having depending integral feet 26, 21 bored respectively at 28, 29 to receive corresponding ones of the guide bar sections I8 and I1. The head I6 is thus adapted to slide axially of the aligned guide bars I1 and I8 as well as to rock or pivot laterally about their longitudinal axis. The tailstock I is of conventional form, being adjustable endwise of the head frame 25 along guide surfaces 30, 3I (Fig. 2) fashioned on the latter'and adapted to be releasably clamped in position by a clamping foot 32 operable by a handle 33. The headstock I4, on the other hand, comprises an upstanding wall 34 (Fig. 3) integral with the head frame 25 and bored to receive a work supporting spindle 35 that carries the center II. An antifriction bearing 36` in a bore 31 supports one end of the spindle 35, whereas the intermediate portion of such spindle is journaled in a second antifriction bearing 38 carried bya tubular extension 39 on a gear housing 40 removably fixed to the wall 34.

As a part of the mechanism for translating the work supporting head I6 in a direction axially of its spindle II, a second head 4I is provided (Fig. 3), the same being tiltable on the guide rod I8 with the first or main head I6 but restrained against a lalmovement with the latter along the guide rod Such second head 4I comprises a main frame casting 42 having a depending lower leg 43 which is bored to receive 'the cylindrical guide rod or sleeve I8. A block 44 fixed to the lower portion of the frame 42 is disposed at the side of the supporting pedestal 24 opposite the leg 43 and coacts with the latter to restrain the head 4I against movement axially of the guide rod I8. In the upper portion of the head frame 42 a sleeve 45 is revolubly journaled and is vopen at its righthand end (as viewed in Fig. 3). The tubular extension 39 on the cover plate 4I! of the other or main head I6 is telescoped within this open end of the sleeve 45 so thatthe two head frames are slidably connected for tilting movement in unison while still permitting displacement of the same relative to each other in a direction axially of the guide rod I8.

Axial feed ofthe main work supporting head I6 is accomplished through the use of coacting feed screw and nut elements, one of which elements is xed to the work supporting spindle 35 carried by the head I6 and the other fixed to the companion or non-translating head 4I. Such screw and nut elements are desirably mounted for ready replacement since the lead of the thread on the feed or master screw must match that being ground on the work piece. instance a feed nut 46 isr clamped to the outer end of the supporting sleeve 45 on the head 4I and,l threaded on a feed'screw 41 keyed to the spindle 35. The nut and its supporting sleeve are normally held stationary, except during adjustment rotation of the same, so that the turning of the feed screw 41 Within the nut 46, 1n-

cident to rotation of the spindle 35,- causes the latter to be moved axially in timed relation with its rotation. A removable dust guard 48 encloses the outer end of the head 4 I.

Rotation of the work spindle 35 and its feed screw. 41 is accomplished from a drive shaft 49 In the present (Fig. 3) disposed concentrically with the axis of tilting or pivotal motion of the heads I6, 4I so that the drive connections will remain undisturbed during all tilting movements of the latter. This shaft 49 is journaled 4within the tubular shaft 23 heretofore mentioned and is driven by a worm gear 5I) (Figs. 3 and 6) fixed to its outer end and meshed with a worm 5I which is in turn connected by a pulley 52 and belt 53 with a reversible electric drive motor 54 fixed to the lower portion of the machine base 2| (Fig. l). A pinion 55 fixed to the drive shaft 49 meshes with a gear 56 carried by a shaft 51 journaled Within the block 44. For the drive connection for revolving the spindle 35 the shaft 51 has a sliding spline connection 58 with a shaft 59 journaled in the main head I6 and carrying a gear 6I). The latter gear meshes with a second gear 6I rigid with a hub sleeve 62 keyed to the spindle 35. As is customary in machines of the general class here under consideration, provision is desirably made for automatically reversing the drive, as for example by the reversal of the motor 54 at the end of each traverse of the work past the grinding wheel so that the work will reciprocate to `and fro past the wheel. Since controls for such purpose are well-known, however, ina variety of forms in the art and since they do not enter into the present invention, detailing here is unnecessary.

Provision is desirably made for lead pickupand backlash compensation. For that purpose a worm wheel 63 (Fig. 5) is fashioned on the exterior of the feed nut supporting sleeve 45 and meshed with a worm 64 carried on a shaft 65 journaled in the head frame 42. Either rotation or axial movement of this shaft 65 correspondinglyfturns the sleeve 45 and feed nut 46, thereby shifting the work supporting spindle 35 axia1ly.

For feed pickup the shaft 65 may be turned by a handwheel '66 located conveniently at the front of the machine (see also Fig. l), whereas'for purposes of backlash compensation fluid pressure is applied (from a suitable source, not shown) alternatively to opposite ends of a piston 61 fixed to the shaft 65 for urging the same in a directionv appropriate to take up backlashfor .the particular direction of rotation selected for the spindle 35.

Progressive tilting motion is imparted to the work supporting head I6 in timed relation with its translation,4 for use in grinding tapered work through the action of an adjustably inclined cam or taper bar 68 pivoted to this head at 69 and locked in selected positions of angular adjustment, the bar being arranged to ride over an upwardly projecting pin 10 (Figs. 1, 2 and 5), whereas periodic in and out tilting of the head in timed relation with its rotation, for use in relief grinding, is accomplished bythe action of a cam 1I (Fig. 5) 'in periodically tilting a pivoted transverse bar 12 on the outer end of which the pin 18 is mounted (Fig. 5). The cam 1I is of the peripheral type and comprises a disk eccentrically fixed to a shaft 13 journaled in an intermediate supporting member 14 hereinafter more particularly described, and is driven in timed relation with the spindle 35 from the shaft 49 through a set of pick-off gears 15, 16, 11 and 18 arranged to remain in mesh throughout the range of tilting movement of the intermediate support 14. The transverse bar 12 is pivoted on this same intermediate support 14 for tilting motion about a generally centrally located adjustable pivot point.

To afford an adjustable pivotal support fo;` the bar 12 such bar is slotted longitudinally as indicated at 19 (Fig. 4) and a parallel slot is provided at 8| in an upstanding web 80 on the intermediate support 14. Such web is recessed as indicated at 8Ia at the ends of, and along the rear of, the slot 8| to permit insertion and removal of parts so that the slot 8| is in effect dened between two opposed ribs included in the web 80. A bolt 82 passes through these two slots 19, 8| and has telescoped on it a bushing 83 with an end flange 83a. Tightening of a nut 82a threaded on the bolt 82 thus clamps the web 80 between the opposed headof the bolt and flanged end of the bushing 83 to hold'the latter rigidly -in a selected position of adjustment along the pair of depending lees 89 on the latter (see also Fig. 5). Such legs are pivoted to the inner end of links 90, the latter being pivoted at` their opposite ends on trunnions 9| projecting laterally from a head 92 rotatably mounted on the inner end of an axially movable size control screw 93.

The screw 93 is threaded within `a piston 94 (Fig. 2) comprised in the fluid operator 88. Such piston is slidable within a cylinder V95 and keyed at 98 against rotation. The cylinder is, on the other hand, i'lxed in a body bracket 91 mounted Ain a recess in the front of the machine base 2|, and having a removablecover plate 98 overlying y the same, as well as an integral face plate 199 at its length of the slot 8|. `A second bushing 84 is journaled on the first bushing 83 and is releasably clamped to the bar 12 by a nut 84a threaded on such second bushing. To change the location of the pivot point for the bar 12 both the nuts 82a and 84a are loosened and the bushing and bolt assembly slid along the registering slots 19, 8|, being retightened at the selected new location. Y

In some instances, as for example in grinding a tapered tap, it is necessary to use both th taper bar 88 and th'e relief control cam-1I for simultaneously varying the position of the work piece (through tilting of the head I 6) relative to the grinding wheel. In other instances it may be desirable to disable either or both the taper bar 68 and the cam 1I. To disable the taper bar it is necessary merely to lock it in such position that its lower edge is exactly horizontal or, in other words, in zero taper position. On the other hand, to disable the cam 1I, the nut 84a is loosened, the bar 1.2 slid outward until the cam 1I no longer contacts it, and the bar locked in such position by a clamping bolt (not shown) passed through the registering slots 19, 8|. Variation in the timing of the cam 1| relative to rotations of the work spindle 35 can, of course, be effected at will by substituting appropriately ratioed sets of pick-olf gears 15 to 18 to accommodate the requirements of a particular work piece.

The intermediate member 14 heretofore reouter end. When pressure fluid is supplied (from a suitable source and control valves, not shown) to the left end of the cylinder 95, the piston 94 is thrust to theright, rocking the intermediate support-14 and the head I6 outward away from the grinding wheel I0 to eiect a separation of work and tool. Similarly, when pressure fluid is supplied to the opposite or right end of the cylinder 95, the piston 94 is thrust to the left,

rocking the intermediate and work supports towheel preparatory to starting grinding and in ferred to constitutes a tiltable, but non-translatable, support on which the main head I6 rests. The intermediate support 14, being non-translatable, is adapted for attachment to it of suitable actuating means on the base, as will hereinafter appear, for tilting or rocking the same. The head I8, being restedon the intermediate support 14 beneath it, rocks or tilts with the latter but is free to slide lengthwise over it. The other head 4|, being connected to the main head I6, of

course rocks with the latter. In the present instance the intermediate support 14 is a casting of shelf or apron shape extending generally horizontally beneath the overhanging head I8 (Figs. 2 and 5) and is pivoted by integral upstanding legs 85, 88 (Figs. 3 and 5) on the guide bar I 1 coaxially with the head I6.

A size control operating mechanism, designated generally as 81 (Figs. 1 and 2) and located conveniently at the front of the'machine, is provided for tilting the intermediate support 14 to shift the work toward the grinding wheel in reducing the work to a desired size. Tilting of the intermediate support 14 for quick retraction of the work is, on the other hand, accomplished by a uid operator 88 (Fig. 2). Both the mechanism 81 and uid operator 88 are connected to the rockableintermediate support 14 through a withdrawing the work at the completion of the grinding ol` to interrupt the process. On the other hand, \the coacting operating mechanism 81 is used to effect the precision controlled, and relatively slow, advances of the work as the grinding progresses regilsite to bring the diameter of the work down to accurately determined size.

It is to be observe` that fluid operator 88 does not in any way distu -b the setting of the operating mechanism 8'I an\d that, on the other hand, the taper and relief controls heretofore described function automatically, in whatever manner they may be set to do, contemporaneously with, but without interference with, the size control mechanism 81.

The size control mechanism for turning the size control screw 93 may take a variety of forms. In the illustrative arrangement provision is made for revolving the screw 93 tok,v adjust its axial position either manually or by power. As to the manual operating mechanism, a circular indexing plate |00, having an axial hub |0I, is bolted concentrically to a peripheralflange |02 on t-he forward end of a tubular shaft |03 so that the two are rotatable as a unit. The forward end of the shaft extension of the screw 93 is splined for rotation and relative axial movement in the tubular shaft |03, the latter being journaled in a bushing |04 in the body bracket. An annular dog ring |05 formed in the periphery with a Tl` slot I 08 is rotatable on the flange |02 and supports an annular internal ring gear |01. Meshing with the ring gear |01` is a planetary gear l|08 mounted for rotation on a stub shaft |09 supported in and between the flangel |02 and the index plate |00 to revolve therewith. A stub shaft I|0 is conned in and extends through the hub |0| of the index plate |00, and a coaxial sun gear fixed to the inner end thereof meshes with the planetary gear |08.

Fixed on the outer end of the stub shaft I|0 is a hand wheel II 2. A graduated ring I I3 is rigidly secured to the index plate and rotatably encircles the hand wheel H2. A second graduated ring H4 is rotatably disposed in a notch in the periphery of the ring H3, and is secured against rotation by a key H bolted to a lug H6 on the front of the base 2|. The hand wheel H2 is adapted to be adjustably connected to the index pla'te |00 for rotation therewith, or to be disengaged therefrom for independent rotation, by means of a retractable spring detent H1. The detent is adapted for selective engagement with any one of a series of uniformly spaced index apertures ||1a (only one of which is shown) in disengaged from the index plate |00, the hand Wheel H2 is manually rotatable independently of the dog ring |05 to adjust the feed screw 93 for the purpose of rocking the work supporting head I6 into the initial size setting as determined by the diameter of the work piece W. IRotation of the hand wheel ||2 acts through the sun gear to turn the planetary gear |08 and cause the latter to roll along the stationary ring gear |01 thereby rotating the terminal shaft |03. The degree of adjustmentis indicated by cross graduations on the ring |3 against a reference point on the adjacent ring H4, and fine graduations on the former ring againstreference points on the hand wheel |2. y

A ratchet mechanism is provided for rotating the dog ring |05 through a predetermined degree upon each reversal of movement of the work supporting head I6. The'ratchet mechanism comprises an annular ratchet wheel H8 having external teeth'and is rigidly secured to the dog ring |05 for rotation with it. Rotatable on the outer end of a bushing |04 in position against the face plate 99 is a ring |20 having pivoted thereon a pawl |2| engageable with the ratchet wheel H8 to advance the same upon oscillation of the carrier ring |20. Such ring is notched at |22 to receive a pin |23 projecting from a piston |24 slidable endWise within a cylinder |25 (Fig. 1) integral with the face plate 99. By means of suitable controls, not shown since they form no part of the present invention but a variety of forms of which are well-known in the art, pressure fluid is admitted to alternate ends of the cylinder |25 to oscillate the piston |24 in timed relation with the reciprocation of the head I6.

Turning now to the matter of the mounting of the grinding wheel I0 (see Fig. 2), it will be observed that it is journaled in bearings |26a at the upper end of a generally upstanding bracket |26. On the lower end of this same bracket an electric drive motor |21 is carried on a base |28 pivoted to the bracket at |29 so that the weight of the motor will retain taut a belt |30 which connects the same to the grinding wheel.

Provision is made for adjusting the grinding wheel I0 longitudinally of a work piece carried on the work supporting head I8, as well as for skewing the Wheel axis in accordance with the helix angle of the thread 'to be ground. For that purpose flat, accurately machined surfaces |3|, |32

are provided in opposed relation on the machine base 2| and bracket |26, respectively, such surfaces being generally vertical but inclined slightly forward toward the work in this case. A block |33 (see also Fig. 6) having flat, accurately machined, parallel opposite side faces is sandwiched between the surfaces |3|, |32. This block is releasably secured to the base 2| by bolts |34 having heads received in T-slots |35 extending longitudinally of the surface |3|, the block being accurately guided for adjustment movement axially of the work piece (i. e., longitudinally of the surface |3I) by a key |36. The bracket |26 is, in turn, similarly secured to the block |33 by bolts |31 having heads eceived in T-slots |38 (Fig. 6) which are in this instance arcuate. Adjustment movement of the bracket on the block is accurately guided by an arcuate key |39. The key |39 and slots |38 are centered about a line passing through the axes of the work and grinding wheel. Both lateral and angular adjustment of the grinding wheel l0 can thus be accomplished readily and with precision.

From the foregoing it will be perceived that a grinding machine has been provided incorporating what is, in a structural sense, quite a simple work support, but which aiords a high degree of versatility of operation in moving such support i quick retraction or approach motion for the work (by the hydraulic operator 88) and progressive adjustable tilt of the work support (by the taper bar 68) in timed relation with thework translation for cutting tapers as well as in and out tilting of the work (by the cam 1|) in timed relation with its rotation and translation for relief grinding. Accordingly, the machine is well adapted for grinding threads on either straight or tapered work pieces and for performing relief grinding operations such as are required, for example, in grinding taps. The adjustment and control of these various instrumentalities are simple so that rapid manipulation and high speed production result.

I claim as my invention:

1. A thread grinding machine having, in combination, a base, a rotatively driven grinding wheel mounted on said base, a stationary guide rigid with said base and presenting a cylindrical exterior guide surface positioned. with its longitudinal axis substantially paralleling the axis of rotation of said wheel, a work supporting head and an intermediate support disposed, respectively, above and beiow said guide with the head resting on the intermediate support, both the head and intermediate support being journaled on said guide to swing about the latters axis, means restraining said intermediate support against movement longitudinally of the guide While leaving the head free to slide therealong, power actuated means for translating said-head longitudinally of said guide, and means for adjusting the angle of tilt of said intermediate support to adjust correspondingly the displacement of said head with reference to the grinding wheel.

.2. A thread grinding machine havin'g, in com- Ibm-ation, a base, a rotatively driven grinding wheel mounted on said base, a stationary guide rigid with said base and presenting a cylindrical exterior guide surface positioned with its longitudinal axis substantially paralleling the axis of nut restrained against rotation, and means ini cluding a screw threaded in said nut for operatively connecting said size control device to said intermediate support for rocking the .latter in response to rotation ci' said device.

3. A thread grinding machine having, in combination, va base, a rotatively driven grinding wheel mountedon the base, a stationary guide rigid with said base and presenting a cylindrical exterior guide surface positioned with its longitudinal axis substantially paralleling the axis of rotation of said wheel, a work supporting head having means thereon slidably embracing said guide to Journal the head on the latter for both translatory movement of the head longitudinally of the guide and bodily rocking motion of the head about the axis o1' the guide toward and from the wheel, an intermediate support also journaled on said guide for tilting moyementabout the latter's axis but restrained againstmovement endwise ofthe guide, said intermediate support being positioned beneath the head with the latter resting on it and slidable therealong, a size control device rotatively mounted on said base, a cylinder fixed to said base and having a piston slidable therein, a screw threaded axially through said piston and connected at one end to said in- `termediate support for rocking the latter in response to endwise displacement of lthe screw effected either by shift of the piston under the influence of pressure fluid applied thereto or by threading'of the screw through the piston, `and means forming a spline connection between said i.

size control device and said screw.

4. A thread grinding machine having, in combination. a work support, means including an intermediate support beneath said workv support sustaining the latter with freedom of endwise sliding movement for the work support with reference to the underlying intermediate support, means mounting both said supports for pivotal motion about a common horizontal axis extending longitudinally of the same and restraining the intermediate support against longitudinal motion while leaving the work support free for y such motion,'.means for adjustably rocking Asaid intermediate support about said axis to thereby a cylindrical exterior guide surface positioned with its longitudinal axis substantially paralleling the axis of rotation of said wheel, a head including a frame having a headstock and `a tailstock at opposite ends thereof with a work supporting spindle journaled in said headstock,

and; means includingdepending feet on said stock and tailstock and slidably embracing said guide to journal the head on the lattergfor both' translatory movement of the head longitudinally` of the guide and bodily swinging motion of the head about the axis of the guide toward and from the wheel.

6. A thread grinding machine having, in combination, a base, a rotatively driven grinding wheel mounted on the base, a stationary guide rigid with said base and -presenting a cylindrical exterior guide surface positioned with its longitudinalaxis substantially paralleling the axis of rotation of said wheel, ahead having a work supporting spindle journaled therein, means on said head slidably embracing said guide to journal the head on the latter for both translatoryv Y movement of the head longitudinally of the guide and bodily rocking motion of the head "about lthe axis of the guide toward and from the wheel, a drive motor on said base, and a drive connection from said motor and including a rotatable element concentric withsaidguide axisv for both rotating said spindle and translating said Ihead. 7. In a thread grinding machine, the vcombination of a base having a guide bar rigidly mounted thereon,v first and second heads journaled on said guide for bodily tilting motion thereof about the latters longitudinal axis, means restraining said first head against movement axially of the guide bar, the second head being a-grinding wheel positioned alongside said work spindle for engagement with a workpiece carried by said spindle. 'l

8. In a thread grinding machine, the combination of a base having an elongated guide rigidlyv mounted thereon, first and second heads JQllrnaled on said guide for bodily tilting motion thereof about the latters longitudinal axis, means restraining said first head against movement axially of said guide, the second head being slidable axially along said guide relative to the first head, said first head having an opening therein and a feed nut mounted thereon in alignment with said opening, a rotatable work spindle Journaled in said second head with its axis eccentric to but substantially paralleling said guide, said `spindle having a feed` screw fixed thereto and threaded lin said nut, a tubular projection rigid guide for bodily tilting vmotion thereof about thev latters longitudinal axis, means restraining said first head against movement axially of said guide.

frame located respectively beneath said head`lv the second head being slidable axially along said guide relative to the first head, said first head having a sleeve journaled therein with an open end ipresented toward said second head, a feed nut fixed to the end of said sleeve remote from -said second head and concentric with said sleeve,

a rotatable work spindle journaled in said second headwith its axiseccentric to but substantially paralleling said guide, `said spindle having a feed screw fixed thereto/projecting through said sleeve and threaded in said nut,\a tubular projection rigid with said second head surrounding said spindle and slidably telescopd within saidsleeVe to retain said heads in coincidence of angular adjustment aboutthe axis of'said guide, power means for rotating said spindle and screw, means i alongside said work spindle for engagement with a. work piece carried by said spindle.

10. A thread grinding machine having, in cornfor adjustably turning said sleeve to control the "lead pick-up, and a grinding wheel positioned termediate member and arranged to 'contact' the Aopposite end of said rocker bar for oscillating the latter about its pivot to raise and lower said head in accordance with the movement of said rockerv \bar;\ann means for connecting said cam in driven relationA with said 'power means for rotation of the cam in timed relation with\the rotation of said spindle.\l X, i

\13. Athread grinding machine having, in co bination, abase, a Work support having a work supporting spindle thereon, means mounting said bination, a base, an intermediate support mounted on said base for rocking motion about a horizontal axis, a work support rested on said intermedi- `ate support for sliding motion relativeto the latl ter in a .direction para'lleling` said axis a d mountedfor pivotal motion about the same h rizontal axis as said intermediate support, a rot tively driven grinding wheel mounted on said base alongside said worksupport, means for adjusting the angle of tilt of said intermediate support to tilt the work support correspondingly towardor away from the grinding wheel, and means including adjustable engaging elements carried A respectively by said -intermediate support and said worksuppoit for progressively tilting the lat- \ter about\said axis relative ,to the intermediate support inthe course of sliding motion of said work support along they intermediate support.

11. A thread grinding machine having, in combination, a base, an intermediate,supportmounted on said base for rocking motion bout a horizontal axis, a head having-.a work su orting i pindle journaled therein, said head being ested o said intermediate support fo sliding m tion relative to the latter in a directi lparalleling said axis, means connecting` said head to said base for tiltsupport about said axis, power means fory rotating said spindle and translating said head in timed relation, a rotatively driven grinding wheel mounted on said base alongside said work support, means for adjusting the angle of tilt of said intermediate support to tilt the head and its work supporting spindle correspondingly toward or away from the grinding wheel, and means including a cam driven by said power means for progressively tilting said head about said axis relative to the intermediate support in timed relation with the rotation of said spindle.

12. A thread grinding machine having, in combination, a base, an intermediate support mounted on said base for rocking motion about a horizoning motion of the head with said intermediate tal axis, a head having awork vsupporting spindle Journaled therein, said head being rested on said intermediate support for sliding `motion relative to the latter in a direction paralleling said axis,

means connecting said head to said base for tiltingr motion of the head with said intermediate support about said axis, powe,r means for rotating said spindle and translatingsaid head in timed relation, a rotatively driven grinding wheel mounted on said base alowgside said work support, means for adjusting heangle f tilt oi said work upport on said base for rocking motion about a horizontal axis paralleling said spindle and for t nslation ina direction paralleling such axis, said" base presenting a generally upright planar surface paralleling said axis, a grinding wheel disposed alongside'v said `work support in position `for" the support to rock toward and away ifrom the same, a mountinglbracket for said wheel presenting a surface opposed tosaid surface on the base, a flat block interposed between said opposed surfaces,an`d means* keying said block for E adjustment of the same along said surface on the base in a direction parallelin said 'axis as well as for angular adjustment of thje bracket relative to said block about an axis passing between the axis of said grinding wheel and the axis of said spindle. l 14. Ay thread grinding maehine comprising, in combination, a base, a tool head on said base and` supporting a rotary grinding wheel, an inter` mediate supporupivotally mounted on said base for rocking motion transversely of the axis of said wheel, a work support pivotally mounted on said base over said intermediate support for rocking.

motion transversely "of said axis and for translation e generally longitudinally of said axis, a work spindle mounted in said work support, means for driving said Work spindle and translating said work support in positivetim'e'd relation and in all pivotal positions of saidiwork support, means on said intermediate supprt for supporting said work support, means for rocking sa'd support` "simultaneously as a unit, and means Ior roeking mediate support. y

15. A thread ,grinding machine comprising, inw,

said work support independently of "said interl e combination, a base, a tool head on said base` and supporting a/'rotary grin/,ding wheel, an intermediate support pivotally mounted o sai base for rocking motion transversely of t/ e axis of said wheel, a work support pivotally mounted on said base over said intermediate support for rocking motion transversely of said axis/ and for translation generally longitudinally of lsaid axis, a work spindle mounted in said work support, means for driving said work spindle'and'translating said work'support in positive timed relation and in all pivotal positions of ,said work support, means on said intermediate/support for supporting said work support, means-,ifor rocking said supports simultaneously as a unit, andselectively available means for rocking said work intermediate support to tilt thehead and its work Support relative t0 Said intermediate SHDPQT iill j 2,888,064 "timed relationwi'th the-translation oi said work support.

16. A thread grinding machine comprising, in combination, a base, a tool head on said base and supporting a rotary grinding wheel, an intermediate support pivotally mounted on said base'ior rocking motion transversely of the axis of said wheel, a work support pivotally mounted on said 4said work support for oscillating the latter relative to said intermediate support.

17. A thread grinding machine comprising, in combination, a base, a tool head on said base and supporting a rotary grinding wheel, an intermediate support pivotally mounted on said base' for rocking motion transversely ofthe axis of said wheel, a work support pivotally mounted on said base over said intermediate' support for rocking motion transversely of said axis and for translation generally longitudinally of said axis,

x a work spindlemounted in said work support, means. for driving saidiwork spindle and transbase over said intermediate support for rocking lating said work support in positive timed relation and in all pivotal positions of said work suD- port, means on `said intermediate support for supporting said work support, means for rocking said support simultaneously as a"'unit, means for progressively tilting said work support relative to said :intermediate support in timed relation with -the translation of -said work support, and means driven in timed relation with the rotation `of said spindle for oscillating said work support relative to said intermediate support.

18. A thread grinding machine comprising, in combination, a base, atool head on said base and supporting a rotary grinding wheel, an intermediate support pivotally mounted' on said base for rocking motion transversely of the axis of said wheel, a work support pivotally mounted on said basev over said intermediate support for rocking `motion transversely of said axis and for translation generally longitudinally of said axis, a work spindle mounted in said work support, means for driving said workspindle and translating said work support in positive timed relation and in all.

pivotal positions of said work support, means on said intermediate support for supporting said work support, means operable in timed relation with the reciprocation of said work support for imparting successive increments of rocking movement to said supportsimultaneously as a unit, and means for rocking said work support relative to said intermediate support.

AUGUST F. MARKU

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