US1493212A - Automatic lathe - Google Patents

Description

May 6 1924. 1 493 2 J- .H. MANSFIELD AUTOMATIC LATHE Filed May 14 1920 4 Sheets-Sheet 1 May 6 1924?.

1,493,212 J. .H. MANSFIELD AUTOMATIC LATHE Filed May 14, 1920 4 Sheets-Sheet 2 Mayfi, 1924. 1,493,212

J. H. MANSFIELD AUTOMAT I C LATHE Filed May 14, 1920 4 Sheets-Sheet 5 J. H. MANSFIELD AUTOMATIC LATH Filed M y 4 Sheets-Sheet 4 JUDSON H. MANSFIELD, OF ROCKFORD, ILLIHOIS, ASSIGNOR TO GRELEE BEDS. 4% 60., F ROCKFDRD, ILLINOIS, A. CORPORATION OF ILLIETQIS.

AUTOMATIC LATHE.

Application filed may 14,

1 art of turning, and to that class of lathes in which the tools are automatically moved through predetermined operations,

More particularly, I have des1gned an automatic lathe especially adapted for handling a work-piece, such .as a shaft or tubing requiring turning at both ends. These turning operations I propose to do simultaneouslyto expedite and economize production. xamples of such work pieces are rear axle shafts. torque tubes and propeller shafts for automobiles, trucks and tractors, and armature shafts for electric motors, generators, etc. However, my improvements are not limited to the production of these particular work-pieces, but are adapted for universal work of this general character, as will be better appreciated hereinafter.

One of the primary objects of this inven- 0 tion is the provision of an automatic lathe of generally improved and novel construction designed to expeditiously and accurately turn work-pieces of the character described. -In this regard I have aimed not 5 only to expedite and economize production of such work-pieces, but'more particularly to secure accuracy in duplication thereof.

Another important object of my invention is the provision of automatically conm trolled and operated tools for performing a number of turning operations, on each end portion of a work-piece, employing any required number of turning, facing and forming tools for this purpose, thereby performing in what might be termed a single general operation, the work which heretofore with the use of ordinary turning equipment required many separate operations.

Still another important object is the provision of a lathe which supports the work piece at both ends as by means of centers 1920. Serial No. 881,431.

I have also aimed in the production of an automatic lathe embodying the characteristics described, to so contruct and arrange the co-operating instrumentalities as to secure an exceptionally high degree of precision and accuracy in the duplication of work, so that in the production in large numbers of machined parts such as mentioned, a high standard of efficiency is obtained.

My invention further contemplates in a lathe in which the work-pieceis supported at its ends between centers and driven medially, the provision of a tool carria e at each end of the lathe equipped with a ront cross tool slide and a cam bar for actuatin a rear cross tool slide, and a separate eed screw for each carriage, the operation of which transmits feed movement to its respective carriage lengthwise on the lathe bed and cross feed movement to thefront and back tool slides. Ihus, by the use of a single feed screw for each tool carriage, many practical advantages are obtained. The problem of feeding a large number of tools is made exce tionally simple. The construction is con ucive to accuracy, longevity and efficiency. Many other practical advantages are obtained which will be manifest to those skilled in this art.

I have alsoaimed to provide a lathe of the character'described in which the tool carriages maybe operated through their predetermined movements either by power. or hand in a very simple and practical manner.

A still further object resides in the provision of an automatic lathe of the foregoing character designed along such lines as to enable production of the lathe as a commercial product at a comparatively low cost considering the functions of the machine.

Other objects and attendant advantages will be appreciated as the invention becomes better understood by reference to the following description when considered in connection with the accompanying drawings, m which- Figure 1 is a front elevation of an automatic lathe embodying my improvements;

Fig. 2, a plan view of the lathe;

Fig. 3, an end view thereof, looking at the left hand end of Fig. 1;

Fig. 4, a vertical cross-sectional view taken substantially on the line 4-4 of Fig. 1;

Fig. 5, a face view of the center driving chuck;

Fig. 6, a vertical sectional view through the chuck and the driving gears therefor, taken substantially on the line 66 of Fig. p

Fig. 7, a fragmentary sectional view through the front portion of one of the tool carriages, taken crosswise of the lathe, showing the front cross tool slide in starting position;

Fig. 8, a sectional view taken substantially on the line 88 of Fig. 7;

Fig. 9, a diagrammatic view of the cross tool slide operating-means shown in Fig. 7, moved to the in-feed position; and

Fig. 10, a diagrammatic view showing one example of the tool lay-out for a particular piece of work.

The bed of the lathe designated generally by character is suitably supported as shown, and shaped to provide outer and inner sets of longitudinal ways 16 and respectively, co-extensive with its length. Upon the ways 20 near the ends of the bed are mounted tail stocks 17 and 18 similar in construction, each carrying an axially adjustable spindle 19 equipped with a center 21 upon and between which the work-piece is supported for rotation.

A suitable driving chuck is employed for driving the work-piece at a convenient point intermediate the centers. -'A suitable chuck or gripping device may be employed for revolving the work-piece; consequently that shown will be but briefly described. Referring to Figs. 5 and 6, it will be observed that a plurality of jaws 22 pivotally supported on a centering plate 23 and constantly urged by springs 24 in a direction to grip the work, are adapted to be thrown outwardly away from the work by oscillation in a counterclockwise directionof a throw-out plate 25. The centering plate 23 has diametricallyv opposed radial ribs 26 on its rear face fitting in complemental grooves in the centering plate 27, and this latter plate has similar ribs 28, spaced 90 degrees from the rib 26 and fitting in grooves in the drivin member 29, which is suitably supported y means of ball bearings on a casing head 31, in turnrigidly but adjustably mounted on the ways 20 on the bed. The plates 23 and 26 supported as shown, will automatically accommodate themselves,

- the drive to a second feed screw 41.

and consequently the jaws, to the work-piece in the event that the central portion thereof is eccentric with relation to the centers 21. The jaws are self-gripping as will be obvious. The chuck is driven through the agency of gears 32 and 33 from a driving shaft 34 which extends from end to end of the lathe bed between the sides thereof.

The shaft 34 may be power driven in any suitable manner, and in the present instance I employ a motor for this purpose, mounted upon and in fixed relation to the bed. As shown in Fig. 1, the drive pinion 35 of the motor meshes with a gear 36 fixed to the main drive shaft 34. By means of a suitable friction'brake 30 adapted to be applied by operation of the hand lever 37, the operator may check the momentum of the driven parts and thus quickly stop the machine after the motor has been shut ofi.

At the opposite end of the lathe, shown in Fig. 3, the shaft 34 transmits the drive through a system of gearing, to the feed screw 38 and to a shaft 39 which transmits This system of gearing may be of any suitable or preferred construction, and it shall contain provision for reversing the drive of the feed screws and stopping them at the end of a cycle of operation. This may be done by the inclusion of suitable clutch or reversing mechanism such as may be actuated in part by manual operation of a shifting lever 42 and actuation of a control rod 43 by travel of one of the tool carriages.

In the present case, it is deemed unneces- I sary to illustrate the particular system of feed gearing'and reversing mechanism inclosed by the housing 44, for the reason that any suitable mechanism of such character may be employed. However, a suitable example of such mechanism is disclosed in my U. S. Letters Patent No. 1,376,714' for a carriage feed and stop mechanism, and it will suffice in the present case to. state that the continuous drive of the shaft 34 is transmitted to the secondary drive shaft 39 and.

on the outer ways 16 at each end of the lathe. Each of these carriages designated generally by characters'45 and 46 co-operates with its respective feed screw 38 and 41 and is adapted to be fed lengthwise there- .by on the bed in a manner presently to be described. These carriages and appurtenant parts are substantially identical in construction, although the tool holders per so will invariably be different, because in fact in nearly every job the cuttingoperations to be performedon each end of the work-piece I is are different. Each main carriage carries a front cross tool slide 47 and co-operates with a back cross tool slide 48, and also carries mechanism whereby upon travel of the carriage lengthwise of the bed by means of its respective feed screw, predetermined cross feed movements will be imparted to the front and back tools. In other words, in each instance the feed screw is the source of power for transmitting the feed movements ent No. 1,376,715, which contains a more thorough explanation of the construction and operation and advantages thereof than is necessary in this case.

Referring now more particularly to Figs. 7 and 8 showing the driving connection between the feed screw 38, the main carriage and its cross tool slide 47, it will be seen that the latter is adapted to be manually adjusted crosswise of the bed by operation of a hand wheel 49 which turns the screw shaft 51 connected to the cross tool slide, and that this slide may be fed in and reversed by moving the yoke bracket 52 crosswise of the bed. An eccentric 53 disposed between hardened plates 54 and 54 on the yoke 52 and supported by trunnions 55 in turn supported by bearings 56 on the main carriage, is adapted to be moved rotatably for feeding the tool slide 47 crosswise. An adjustable stop 57 carried by a bolt 58 fixed to the yoke 52 is adapted by contact against the fixed abutment 59 when the eccentric reaches the infeed position shown in Fig. 9, to insure metal-to-metal contact between the high por- .tion 61 of the eccentric and the plate 54',

thereby securing absolute accuracy in controlling thein-feed of the front cross tool slide. By finishing the high portion 61 of the eccentric on an arc concentric with the trunnions 55, any chance of variation in the extent of the in-feed is eliminated. Half revolution movements are imparted to the eccentric 53 for advancing and retracting the cross tool slides. These movements are obtained through the agency of a gear62 fixed to one of the trunnions 55 and meshing with a gear 63 rotatable upon the periphery of a ratchet member 64 splined on the feed screw 38, and driving dogs 65 and 66 carried by the gear 63 and adaptedto be respectively moved into and out of the recesses 67 and 68 in the ratchet member. These driving dogs are constantly urged by suitable springs in a direction to engage in said recesses and It might be are adapted to be moved out ofthe same by stationary pins 69 and 71. A nut 72 on the feed screw 38 held against rotation by the key 73, is adapted by engaging the opposed surfaces 74 and 75 of the main carriage, to feed said carriage lengthwise in opposite direction by similar rotation of the feed screw. A lost motion is provided between the nut and carriage to permit certain rotative movement of the feed screw for the purpose of operatin the cross tool slide'independently o and efore operation of the main carriage. The foregoing mechanism functions as follows: Themain carriage 45 is shown in Figs. 1, 7 and 8 in the startingposition.

Upon rotating the feed screw 38 in a counter-clockwise direction viewing Fig. 7, the ratchet member 64 will revolve the gear 63 throu h the agency of the driving dog- 65, and t us revolving the eccentric 53 in a clockwise direction until it has traveled 180 degrees into the position shown in Fig. 9,

and said'slide has been fed in to position the front tools at their working depth. At this point, the driving dog 65 will be disengaged y the pin 69 and the main carriage which has remained stationary will be fed to the right, Fig. 1, by contact of the nut 7 2- against the surface 75, thus causing the tools to traverse the work-piece lengthwise. The main carriage will continue in this movement un til the tappet 76 on the carriage strikes the stop.77 on the control rod 43 and actuates the reverse clutch shaft 78, Fig. 4, causing- I the drive of the screw 38 to be reversed.

During approximately the first half-revolution of this reverse movement the driving dog 66 will engage the first approaching recess 68 causing the eccentric 53 to be revolved in a counter-clockwise direction until this dog 66 is withdrawn by the stop pin .71, thereby stopping reverse movement of the cross tool slide 74. Continued rotation of the feed screw 38 in the same direction will return the main carriage to starting position at which the tappet 76 will actuate the stop 79, causing the feed screw 38 to be stopped.

During drive of the feed screw after the cross tool slide has been moved either in or out, the drivin dog not engaged by either the pin 69 or 71 will be held retracted by action of a split friction ring 81, the end of which bears against such dog and prevents it from dropping into the notches in the ratchet member. From the foregoing, it will be seen that the feed screw 38 transmits feed movement to both the main carriage 45 and cross tool slide 47 and that the operation is first to advance the front turning tools to working depth, then feed the main carriage lengthwise of the work until a predeter mined point in the travel is reached, and

then upon reversing the drive of the feed screw to retract the cross tool slide and then return the main carriage tostartmgposit'ion.

The feed screw in addition to transmitting feed movement to the main carriage and front cross tool slide also imparts feed movement to the back cross tool slide. This tool slide 48 may be suitably supported on the main carriage for movement toward and from the axis of the work-piece, preferably in an inclined plane, as is most practical in machines of this kind. In the present case, this tool holder 48 is slidably mounted upon a base member 82, adjustable longitudinally of the bed upon a supporting bracket 83 rigidly but adjustably secured to an upright part 84 of the adjacent tail stock 17. Upon a the rear portion 85 of the main carriage is adjustably mounted an upright base member 86 to which is attached a cam bar 87 extending lengthwise of the bed through the slidesupporting bracket 82 and in association with bearings thereon. The back tool slide 48 carries a roller 88 disposed in the cam slot 89 in said cam bar, and it will be manifest that when the main carriage travels lengthwise of the bed, the cam bar 87 will i be correspondingly moved and thus feed the back tool slide 48 toward and from the workpiece'according to the shape of the cam slot. It follows, therefore, that the front turning tools are fed in to the work and then lengthwise thereof, and that the rear facing or forming tools as the case may be, are fed in be mounted on each front and back cross tool slide, it being observed that the back cross-= to the work by operation of the single feed screw 38. h

As mentioned in the preface, this lathe is designed for automatically turning both ends of a shaft or other workpiece to the requisite shape, by performing a relatively large number of turning,-facing and forming operations to'a fine degree of accuracy. For this purpose, a multiple of tools may tool slides do not move lengthwise of the work-piece as do the front slides, and for this reason the tools on the'latter may be caused to move relatively to the tool holder as by means of templates, thus producing tapered or other irregular surfaces. In this regard, I have shown for purpose of illustration, a single lay-out of-an ordinary job done by this machine, reference being had to Fig. 10.

This shows diagrammatically the set-up of the tools for turning an automobile rear axle. The tool holder on the front cross tool slide of the carriage 45 is equipped with three turning tools 91, 98 and 99, the front tool holder of the carriage 46 with two turning tools 92 and 100, the back tool slide of the carriage 45 with a formcutter 93 and a facing tool 94, while the back tool slide of the carriage 46 is equipped simply with a form cutter 95. Tool templates 96 and 97 co-operate with the tools 98-99 and 100 respectively, for varying the position thereof as the tools are carried lengthwise, to thereby produce either tapered or other irregular effects, as may be desired. These templates may be suitably supported as from the tail stocks 1? and 18. The tools in the position shown in Fig.- 10, are at the end of then cutting movement and about to be retracted and returned to starting position. It will be manifest from the foregoing that in starting the operation, as the carriage 45 moves to the right the first tool 91 will turn the workpiece to the diameter of the p0rtion'91', the next succeeding tools 98 and 99 as controlled by the template will turn the portions 98 and 99', respectively. And as the shown in Fig. 1 and the main driving shaft 34 revolving, no action takes place until the operator throws in the feed clutch by operation of the lever 42. This, causes both feed screws 38 and 41 to be revolved and the front cross tool slides of both the carriages 45 and 46 to be fed in. At the completion of this infeed, both the carriages 45 and 46 will be fedlengthwise of the bed toward each other, thereby bringing the tools of both the front and back ,cross tool slides into enga ement with the work-piece as determined iy the setting of these tools and the arrangement 100 of the templets and back tool cams. When the carriages reach a predetermined point in their travel toward each other, the drive of the feed screws38 and 41 will be reversed,

thereby withdrawing the tools carried by the front cross slides and returnin the carriages to the starting position, an likewise withdrawing the back tools.- At this position, the drive of the feed screws 38 and 41 will be automatically stopped and the operator may then stop the machine as mentioned above, to change the work-piece.

It will be observed that the shaft 39 is in constant driving-connectionwith both feed screws 38 and 41, so that when the feed driving mechanism is disengaged the shaft 39 is free'to be operated by hand for the purpose of moving both tool carriages and their tool holders through their respective cycles of operation. To this end, I connect a hand no wheel 101 to the shaft 39 through the a ency of suitable gearing such as a pair of evel gears, not shown. It will thus be seen that by turning the wheel-98, the tools may be moved through their complete cycle of 0 er- I 5 ation, or any portion thereof, as desired when setting up the tools.

It is believed that the foregoing conveys a clear idea of the objects prefaced above,

and while I have shown for purpof g aaeaaia illustration but a single working embodiment of my invention, it should be understood that considerable change might be made in construction and arrangement of the co-operating instrument-alities without departing from the spirit and scope of the invention as expressed in the appended claims, inwhich- I claim:

1. In a lathe, the combination of a bed, a center support upon each end of the bed equipped with centers between and upon which the work-piece is supported for rotation, means intermediate said centers forrevolving the work-piece, a tool carriage mounted on the bed at each side of said work-driving means for movement lengthwise on the bed, a cross tool slide on each carriage, a feed screw for each carriage connected therewith so that rotation of the screw in opposite directions will propel the carriage back and forth on the bed, means on each carriage operated by rotation of its feed screw for advancing and retracting its tool slide, and mechanism for causing each carriage and its tool slide to be independently operated at different periods in and by the rotation of its respective feed screw.

2. In a lathe, the combination set forth in claim 1, including a common driving mechanism for revolving both feed screws, and means actuated by movement of one of the carriagesfor controlling the operation of. said driving mechanism.

3. In a lathe, the combination of means for supporting a work-piece at both ends for rotation, means for revolving the workpiece, a tool carriage adjacent to each end of the work-piece adapmd to travel longitudinally thereof, a cross-tool slide on each carriage, a feed screw passing through each carriage and threadingly connected therewith so that upon rotation of the feed screw in opposite directions its carriage will he traveled back and forth, means on each carriage adapted to be operated by rotation of its feed screw for advancing. and retracting its tool slide, and means for causing the feed screws to automatically move the tool slides and carriages in a cycle commencing with the tool slides retracted and consisting in feeding the tool slides into a predetermined depth for cross feed cuttin feeding the carriages toward each other or longitudinal feed cutting retracting the. tool slides and returning the carriag to the starting position.

4. In a lathe, the combination set forth in claim 3, including manually operable means for operating the feed screws for duplicating the carriage and tool slide cycle.

5. In a lathe, the combination of means for supporting a work-piece at both ends for rotation, means for driving said workpiece medially between its ends, a tool car riage adjacent to each end of the work piece, a cross tool slide on each carriage,

a feed screw co-operating with each carriage, means for driving the said feed screws respectively from the adjacent end. of the lathe, and mechanism operated by each feed screw for imparting to its respective cross tool slide in-feed and reverse movements and for moving its respective carriage lengthwise on the bed.

6. In a lathe, the combination of means for supporting a work-piece at both ends for rotation. means for driving said work-: piece medially between its ends, a tool carriage adjacent to each end of the workpiece, a cross "tool slide on each carriage, a feed screw co-operating with each carriage, means for driving the said feed screws respectively from the adjacent end of the lathe, said feed screws being driven from a common source and simultaneously revolved in forward and reverse movements whereby to simultaneously operate the cross feed slides, and the lead of said screws being opposite so that said carriages will be si multaneously fed toward and away from each other.

7. In a lathe, the combination of means for supporting a work-piece at both ends for rotation, means for driving said work-piece medially between its ends, a tool carriage adjacent to each end of the work-piece, a cross tool slide on each carriage, a feed screw co-operating with each carriage, means for driving the said feed screws respectively from the adjacent end of the lathe, said feed screws being driven from a .common source and simultaneously revolved in forward and reverse movements whereby I,

td simultaneously operate the cross feed slides, and means actuated by one of said carriages at a predetermined point in its lengthwise feed movement for efiectlng reversal of the drive of both feed screws and at a predetermined point in the reverse movement to stop the drive of said feed screws.

8. In a lathe, the combination of means for supporting a work-piece between cen ters; and'driving it medially, a front and a rear cross tool slide for each end portion of the'work-piece, the front slides being also movable lengthwise thereof, a f screw for moving each front cross slide length wise, and means operated by rotation of the feed screws for moving the front and back tool slides toward the work-piece in prede= termined timed relation.

9. In a lathe, the combination of means for supporting a work-piece between centers and driving it medially, a front and a rear cross tool slide for each end portion of the work-piece, the front slides being also movable lenhwise thereof, a feed screw for moving a front cross slide lenhwise,

and mechanism operated by movement transmitted from said feed screws for initially-feeding both front cross slides in toward the work-piece, then feeding them lengthwise thereof, and for feeding the back cross slides in toward the work at a predetermined time in the lengthwise movement of the front cross slides.

10. In a lathe, the combination of means for supporting a work-piece between centers and driving it medially, a front and a rear cross tool slide for each end portion of the work-piece, the front slides being also movable lengthwise thereof, a feed, screw for moving each front cross slide lengthwise, means operated by rotation of the feed screws for moving the front and back tool slides toward the work-piece, one, of the front slides carrying a tool slidable thereon crosswise of the axis of the work-piece, and

a template for determining th position of said slidable tool as it is moved lengthwise of the work-piece.

11, In a lathe, the combination of means for supporting a work-piece at both ends for rotation, means for driving the work-piece intermediate its ends, a pair of tool carriages one adjacent to each end of the work-piece and adapted for movement lengthwise thereof, a cross-tool slide on each carriage, screw means passing through each carriage, threadingly connected therewith and adapted upon rotation in opposite directions to travel the carriages back and forth, and an independent operating connection between each tool slide and said screw means for advancingfland retracting its slide upon rotation of said screw means in opposite direc tions.

12. In a lathe, the combination set forth in claim 11, including means for causing the carriages and tool slides to be operated during separate periods of rotation of said 13. In a lathe of the character described, the combination of means for supporting the work for rotation, a pair of tool carriages one adjacent to each end of the work and movable lengthwise of its axis of rotation, a feed screw for s0 moving each carriage, a cross tool slide on each carria mechanism for simultaneously driving t e naeaaaa riages back and forth, and means on each carriage adapted to be intermittently connected to said screw means for advancing and retracting its tool slide.

15. In a machine tool, the combination set forth in claim 14, in which said cross-tool slides are at the front of the machine, a back cross-tool slide, and means operated by travel of one of the carriages for advancing and retracting the back. cross tool slide.

16. In a lathe, the combination of means for supporting 'a work piece at both ends for rotation, a pair of tool carriages movable lengthwise of said axis of rotation, a feed screw for so moving each carriage, a cross tool slide, means for causing said slide to be moved in a plane transverse to said axis by rotation of one of said feed screws, and means for simultaneously revolving both feed screws for moving in timed relation "the carriages toward and from each "other and said cross tool slide toward and from the work.

17. A machine tool of the character described comprising a bed, means thereon for supporting a work-piece at both ends for rotation, means for medially gripping and revolving the work piece, a pair of tool carriages movable lengthwise on the bed, one at each side of said work revolving means, a feed screw passing through each of said carriages and o eratively connected thereto for traveling't e carriages toward each other in a feed movement when revolved in one direction and away from each otherwhen revolved in the opposite direction, a cross-feed tool holder on each carriage, and mechanism on each carriage adapted to be automatically brought into and out of connection with its feed screw for feeding its tool holder in to the workpiece and retracting the tool holder, and means for causin said feed screws to automatically feed said carriages and tool holders in a cycle starting with the tools withdrawn from the work, said cycle consisting in moving the tool holders inwardly to thereby feed the tools to predetermined depth, then moving the carriages on the bed to feed the tools lengthwise of the work and then retracting the tools by withdrawal of the tool holders, and finally moving the carriages lengthwise on the bed to the starting position.

18. The combination of a bed, means for support-ing a work-piece at both ends-for rotation, a driving chuck on-the bed for medially gripping and revolving the workpiece, a carriage at each side of said chuck movable lengthwise 9n the bed, a cross-tool slide on each carriage, screw means assing through each carriage and threading y connecte therewith and adapted to be revolved in opposite directions for traveling'the carmagma riages back and forth on the bed, said screw means having lost-motion connections with the respective carriages so as to turn idly at certain periods without traveling the carriages, and means operated by said screw means during said period for advancing and retracting each tool slide.

19. The combination set forth in claim 18, in which said screw means comprises a separate feed screw for each carriage.

20. The combination set forth in claim 18, including driving mechanism for revolving said screw means in reverse directions, and means operated by movement of one of the carriages for controlling said driving means.

21. The combination set forth in claim 18, in which the last-mentioned means includes a clutch on each carriage adapted for automatically connecting said means to and disconnecting it from the screw means.

22. The combination set forth in claim 18, including a cross-tool slide opposed to one of the first mentioned tool slides, and means for advancing and retracting said opposed cross-tool slide by travel of one of said carriages.

- 23. The combination set forth in claim 18, including a stationary templet co-oper- 'ating with a tool on one of the cross tool slides for imparting movement to. said tool independently of cross-feed of its tool slide.

J UDSON H. MANSFELD.

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