US2382662A - Thread milling machine - Google Patents

Description

Augym, 1945.

FBG.

A. J. FRANCE THREAD MILLING MACHINE Filed Feb. 2, 1942.

e sheets-sheet 1 ATTORNEY.

Aug 14, 1945. A. J. FRANCE 2,382,662

THREAD` MILLING MACHINE Filed Feb. v2, -1942 e sheets-sheet 2 1 wrom ATTORI'YAEY.

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THREAD MILLING MACHINE Filed Feb. 2, :L9/l2 6 Sheets-Sheet 4- v VQINVENTOR.

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Aug. M, 1945-. A. J. FRANCE d 2,382,662

THREAD MILLING MACHINE Filed Feb. 2, 1942 6 Sheets-Sheet 5 TTORNE Y ug. 14, 1945. AQJ, PRANC THREAD MILLING MACHINE 6 Sheets-Sheet 6 R. m m W Filed Feb. 2, 1942 ATTORNY.

Patented Aug. 14, 1945 THREAD MILLING 'MACHINE `Albert J. Prance, Detroit, Mich., assignor to Murchey Machine & vTool Company, Detroit, Mich.,;a corporation of Michigan "v Application February 2, 1942, Serial No. 429,240

3 Claims. 4(C1. :a0-11.56)

The present invention relates to thread milling machines.

Among the objects of the present invention is a thread milling machine which is fully automatic in its operation, is economical to construct and does not easily get out of order.

Another object is a machine which Will produce a more accurate and more flnely finished thread than is the case with .known thread millers.

Another object is a thread miller which, when adjusted for a particular operation will duplicate the work substantially indefinitely withou further adjustment.

Still other objects and advantages will be apparent to those skilled in the` art upon refer- Vence to the following descriptionand the accompanying drawings .in which Figure 1 is anend elevation, partly sectionaLx` as from the right of Figure 3.

.Figure 2 is an end elevation, partly sectional, as from the left of Figure `3. i

Figure 3 is a centralvertical sectional View, with parts in elevation.

Figures 4 and 5 are sectional views. of certain details of construction.

Figure 6 is a partial rear view ofthe maz chine.

Figure 7 is a sectional view showing a detail of construction.

Figure 8 is -a planview of the fluid circulation elements, the connecting conduits being omitted for the sake of clarity.

Figure 9 is an electric wiring diagramand Figure 10 is a uid circulation diagram.

In the drawings, a suitable base III serves as a housing of various elements -and also as a-support, at one end, of the cutting spindle and associated elements and, at the other end, of the Work ysupporting'slide and its associated parts.v

The latter may be and preferably is a'simple sliding table II movable longitudinallyof` the base toward and from the cutter by Vmeansfof a suitable hand Wheel I2 and its vpinion I3-and rack I4.

It is to be understood that suitable work'supporting jigs (not shown) will be used in mounting the work piece thereon; an end of such a f piece being shown in Figure 3 at I5.

The sole function of table II is work-support and movement into and froma suitablelocation for threading. Y

Mounted upon the base III vand in alignment with the `table II is a frame member 2l! `provided with bearings zi in which is mounted for rotation a cylindrical sleeve 22rv bored eccentrically and carrying a secondcylin'drical sleeve 23 also bored eccentrically. Within thhe eccentric bore of sleeve `23 and carriedin suitable antifriction bearings 24 is a toolcarryingspindle 25, an inside threading milling cutterbeing shown at26.

yThe spindle 25 isdriven by means of asuitable sprocket 30 andlink belt 3| from a gear or sprocket v32 (see,Fig.,4) keyed to a short shaft 33 which is driven,'through gears 34 and 35 and shaft 36, from the pulley .31, the ylatter being vin turn driven through'belt 38vby the elec- A tric motor 39. I

In order to provide for the lateral or translative movement of the spindle 25 (to be described) without interference with` lthe, drive thereof, the driving connection from motor 39 to the spindle is arranged to permit such movement, and such arrangement is shown in Figures 2 and 4.

In these figures, the bearing supporting mem'- bers 36a are stationary parts of the supporting base III andhave xed in suitable openings a sleeve 36h serving to support the vshaft 36 in suitable antifriction bearings` 36e. This sleeve 36h also serves as a shaft orspindle uponwhich are rotatably mounted the arms 33a vof the bearing support 33h, having mounted therein the shaft 33, suitable antifriction bearings 33e being provided. Thev assembly. of gears 32 and -34 vwith shaft `33 is, therefore,.movable around .30 and 32 as the spindle moves.

A-variation in the drive speed for the spindle 25 is provided for by mounting the motor` 39 upon va vertically swingable platform 39a to which is attached la .link y39h in turn connected to a threaded shaft 39e coacting'with the bandwheel 39d. 'I'he pulley 38a is so constructedthat its fiangesmove'toward each otheras the motor 39 and its platform are lifted. y

As indicated above, the spindle 25,"i n addition to its rotative `movement'is also movable laterally in order to feed the cutter toward and'from the work. This lateral vor translative movement is produced bythe relativerotatlon of the *two 22E serve as stops for an arm 23A mounted upon sleeve 23 and projecting from slot22A between rails 22B and adapted to coact with the stop Y Loosely mounted upon sleeve 22 is a worm gearl 50 located adjacent the rails 22B and provided with laterally extending ngers SUAspaced sufciently toembrace closely the arm 23A whereby to move the latter between the stop screws 22E,` when said gear isactuated, and thereby move the sleeve 22 as a unit with sleeve 23. Further, in order to provide against movement of sleeve 23 until the arm 23A reaches one of the stopscrews 22E, stationary brake means for sleeve 231s prol vided.

This brake means is shown in Figures 2 and 3 as a brake shoe anchored to the housing 20 as by the screw 52.

The worm gear 50 is driven by a suitable wormv on shaft 53 in turn driven throughthe small gear54 meshing with a large gear 55 fixed to shaft 56 mounted in the housing or frame' 2U of the machine. The outer end of shaft 56 has xed thereon a small pinion 5'! which is adapted to coact with a rack 60, longitudinal movement of which produces the relative movement of the sleeves 22 and 23 and also rotation of these sleeves as a unit. v

Figure 6, showing a rear view of the machine,

- shows the rack 6U and the pressure fluid cylinder 6| within which is a piston (not shown)v connected by rod 62 to the rack and actuated by supplying lluid under pressure to either end of the cylinder through the pipes 63.

In the operation of the machine, as thus far4 described, when an inside thread is to be milled, the work piece. l5 is moved into position over the cutter 26 which is centered with respect to the work because of the relative position of sleeves 22 and 23.

-. When the machine is then put intol operation by setting up the rotation of spindle and starting the operation of rack 60, the worm gear 50 starts to rotate and, through ngers 50A, parl tially rotates sleeve 23 within sleeve 22,' the amount of rotation depending upon the travel of arm 23A between the stop screws 22E, for example, from the position 23AA in dotted lines to the full line position of 23A. 'In this partial relative rotation, the sleeve 22 is held by the brakel until the arm 23A strikes the stop screw and therefore provides for the lateral movement of the spindle 25.

This lateral'movement is adjusted by the screws.

22E and is the feed of the cutter into the work and therefore the depth of the cut.

When the arm 23A strikes the stop screw 22E, the gear 50 continues to turn the sleeve assembly for slightly more than a complete revoluq through the means shown in Figures 8, 9 and 10, in which (in Fig. 8) there is shown a motor 90 directly coupled to a suitable pump 9|, which is arranged to draw suitable fluid from a tank 92 5 serving as a base upon which the motor, pump and other elements may be mounted. The pump 9| draws its fluid from tank 92 through the pipe 93 provided, preferably, with a screen 94.

' .l "From the' pump 9|the f luid'is, conducted to a magnetically a'ctuatedvalve V to the port C and from the valve V is conducted 'through pipes D 'and E to one end or the other of the cylinder 6|, depending upon whether the valve is in position to connect port C with port A, from which leads pipe D, or port B, from which leads pipe E. The

- fourth port Tis 'connected to a pipe T| leading backto the'tank 92.

. In the valve V, the mechanism is so arranged that the ports A and B are alternately connected to port C and port T. When it is desired to actu- .ate the rack 60 ina thread lcutting operation,.the

valve V'is'set to' connect the pump discharge into ,port C withthe port A, whereupon uid is forced directly'to' the end BI of cylinder 5|. Atythe same time, port B is connected to port T for the dis, charge of fluid fromthe end AI of thecylinder Kback to thetank 92.

` This discharge, however, is regulated and 1 throttled, whereby'to'control the speed of movement of the rack.v This throttling and'control lis l provided forby theseveral valves F, G, H and Iof which', the valveuF is a check valve allowing fluid to ilow from the pumpto the cylinder, but preventing back flow.

. I'he valve Gr is a cam operatedl valve actuable yby a cam BDA carried by the rackll. This valve Gis closed or nearly so when the rack is in starting position. If itis desired to provide the rack =with an initial slightly higherspeed, the cam 60A may slope slightly Iupward toward the left end l(Fig. 10), At or near. its other en d it slopes l'sharply upward so as toallow quick and full opening of the valve.

The valves I-I and I arehand-controlled and dial set, and lcalibrated toindicate ,the speed of rack movement. Of these, the valve H is arranged to pass less fluid than the valve I.`

When the nuid'fiowis beginning into end Bl I of the cylinder, the discharge from end AI is through pipe A2 to the valve H, since' both valves F and G are closed toits passage. From valve H the flow is'through pipe HI, and pipe vE back to port B of valve vV which' is connectcdtoport T and through pipeTl totank 92. As soon, .how-

' ever, as'the rack 60 has, moved'far enough to allow the camI 6| 1A`to open or permit the opening of valve G, the flow is through both Valves Hand I, but chiefly through valve I, since the valve G is open. The flow is, ofl course, through valve H, pipe G2, valve G, pipe GI te port B, to port T and thenceftotheftank 92. Consequently, Ythe rack may move at a higheryspe'ed.

When it is desired to return the rack 60 to the vstarting point, the `valve V set so that the port C is connected to the port B and port A connected to port T. In this position of the valve V, fluid y passes from'the pump through pipe E, check valve F,'and directly tothe end AI of cylinder 6|, while the fluid from 4end-BI of the cylinder flows unrestricted through pipe D, valve V, and pipe `T| to tank 92. .Y f

`vIn addition to the several elements of valve V which have already been mentioned.- means isalso provided for permitting the pump 9| lto discharge (5 directlyrback to the tank during the, periodrwhen the rack 6| is at rest. Such means is indicated in Figure 10 by the conduit 9 IA.

In Figure 8, there is also shown a second pump |00, belt-driven by motor 90 and adapted to draw cutting uid from tank IUI (see Fig. 3) and through a suitable nozzle (not shown) flow it over the work and cutter. The pipe 'H32 is shown (see Fig. 3) as the point cf attachment of the nozzle.

In Fig. 9, the power supply lines P lead to the transformer Pl, and thence to a multiple solenoidA switch S to which are connected the solenoids operating the valve V, a pair of rack operated switches, a starting switch and a quick return switch.

In the diagram shown in Figure 9, the valve V is shown diagrammatically being represented as a pair of simple valves actuated by solenoids.

When it is desired to start operation of the rack 60, the rack switch K is held open by a suitable cam on the rack, the button L is pressed and completes a circuit through L2, Lly Sl, solenoid S2, and L3. This circuit closes contacts M and Ml and completes the circuit L2, MI, M2, solenoid M3, L3, thereby operating valve V to start the rack and allowing switch K to close.

At the end of the rack travel, a suitable plate or cam thereon strikes and closes rack switch N, and thereby establishes the circuit through solenoid S3, this circuit being L2, NI, N, N2, S3 and L3 and closing contacts R and RI and opening contacts R2, the latter breaking the holding circuit for solenoid S2.

Contacts Rl complete a holding circuit for solenoid S3, which circuit is L3, Rl, Kl, switch K, N l, L2.

Contacts R complete a circuit L2, R, WI, valve solenoid W, W2, W3, L3, thereby reversing the valve V and consequently the motion of rack 60.

Upon reaching the end of the return stroke, the switch K is openedto break the holding circuit and allow solenoid S3 to become deenergized and thereby reestablish the idle position.

If for some reason, it is desired to return the rack after a part stroke, the button X is pressed. The effect of this is to thereby establish a circuit L2, X, XI, S3, L3. This, of course, has the same effect as described above for the switch N.

It is to be understood that the invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof, and it is desired that the present embodiment be considered in all respects as illustrative and not restrictive; reference being had to the appended claims rather than to the foregoing description to indicate the scope of the invention. I claim:

1. In a thread milling machine, having a pair vof eccentric sleeves, one within the other, and a cutter carrying spindle rotatably mounted within said sleeves, means for relatively rotating said sleeves and then rotating said sleeves as a unit, said rotating means including a reversible hydraulic motor having cam actuated meansfor changing the speed thereof at a predetermined time during the forward or feeding portion of the cycle of operations.

2. In a thread milling machine, having a pair of eccentric sleeves, one within the other, and a cutter carrying spindle rotatably mounted within said sleeves, means for relatively rotating said sleeves and then rotating said sleeves as a unit, said rotating means including a reversible hydraulic motor having means for reversing the flow of uid to and from said motor whereby to reverse said motor, cam actuated means for throttling the outflow of iiuid whereby to regulate the speed of said motor and means for changing the degree of throttling during the forward or feeding portion of the cycle whereby to change the cutting feed.

3. In a thread milling machine, having a pair of eccentric sleeves, one within the other, and a cutter carrying spindle rotatably mounted Within said sleeves, means for relatively rotating said sleeves and then rotating said sleeves as a unit, said rotating means including a reversible hydraulic motor having cam actuated means for changing the speed thereof at a predetermined time, said speed changing means consisting of a plurality of valves capable of passing different amounts of fluid and connected to the outilow of said motor, and means for blocking the flow through one of said valves during part of the operation of said motor and then opening said valve during the remaining part.

' ALBERT J. PRANCE.

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