US2390607A - Hobbing machine - Google Patents

Description

, Dec. l1, 19145- G. L. MERRILL TAL 2,390,607

` HOBBlHG MACHINE Y f 1 INVENTOR. 650055 Metz/LL- BY wsopoescneu/v Eau/nea J' En 71925K/ ATTORNEYS "wf/M157@ am@ Dec. 11,1945. G. L. MERRILL ETAL 2,390,607

` HOBBING MACHINE Filed Dec. 15, 1943' 4 sheets-sheet 2 ATTORNEY5 sig m 5 La Zenmw w .QM @W47 U HEER l Yawn. mmm@ @mf W3 ..||l- .Z f f 7 Z llql IIIIUIIIIH a ywnmmilllwl I ...Iq W H. M rw M W l. ::z 'IF 0067 ,F Mm a l Y W 5 llhullfhwnnmuwu M, M W l-- 4 wlll 3 /f fr PI' /l f b .m 2 M 3 N ,u iu w, T@ .u 6 f a 7 lunml ./IIMOQ [@KL 2 ff a n De@ 11,1945- GL. MERRILL Erm.

HOBBING MACHINE 4 Sheets-Sheet .3

Filed Dec. 13, 1943 .L l, 5 @fbg Tzu N mann .m wnww 1,2. A E f5 ep GZ Dec. 11, 1945- l G. l.. MERRlLL x-:TAL

IIOBBING MACHINE Filed Dec. 13., 1943 4 Sheets-Sheet 4 www @www

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Patented Dec. 11, 1945 s PATENT OFFICE HOBBING MACHINE George Carlin,

L. Merrill, East ICleveland, Theodore F. Cleveland, and Edward J. Batorski,

` `Garelcl Heights, Ohio, assignors to The Cleveland Hobbing Machine Co., Euclid, Ohio, a corporation of Ohio Application December 13, 1943, Serial No. 514,004

` (c1. en -4) s claims.

The present invention relates to hobbing machines and more particularly to hobbing machines ofthe general type shown in U. S. Patents Nos. 2,231,866 and 2,307,428.` i

The principal object of the invention is the provision of a novel and improved hobbing machine especially adapted for cuttingA splines on shafts, gun barrels, and the like, wherein an electric motor or other suitable power source is employed for rotating the tool `and work spindles and for producing a relative feed movement therebetween, and comprising electrically controlled means for automatically rendering the feed means inoperative at a predetermined point in the relative movement between the tooland work spindles without stopping the rotation of the spindles,

The invention resides in certain constructions and combinations and arrangements of parts and further objects andladvantages thereof will be apparent to those skilled in the art to which it relates from the following description of the preferred embodiment described with reference to the accompanyingidrawings forming a part of i this specification in which similar reference characters designate corresponding parts, and in which Fig. l is a perspective View of a bobbing machine embodying the present invention; A

Fig. 2 is a vertical section through the bobbing machine shown in Fig. 1, approximately on the center line with portions shwn in elevation;

Fig, 3 is a section approximately on the line 3 3 of Fig. 2 with portions shown in elevation; Fig. 4 is a section Yapproximately on the line 4-4 of Fig. 3 with portions shown in elevation; Fig. 5 is a section approximately on the line 5 5 of Fig. 2;

Fig. 6 is a view approximately on the line 6,-6

Fig. 'l is a wiring diagram of the electrical circuits `of the machine.

While the invention is susceptible of various modifications and alternative constructions, it is herein shown as embodied in a machine similar to the machine shown in U. S. Patent No. 2,307,423. The preferred embodiment ,shown is hereinafter described in considerable detail but it is to be understood that the invention is not limited to the specic form of machine shown and it is my intention to cover hereby all modifications "and alternative constructions thereof that come within the spirit and scope of the invention as defined in the appended claims. Generally speaking, the machine shown com-V prises a frame consisting of a base A having a vertical column B detachably xed thereto, a work head C slidably supported on vertically spaced pairs of vertical Ways I0 and Il on the column B and a tool or hobhead `D adjustably supported cn a pair of horizontal ways l2 also on the column B and located intermediatethe spaced vertical ways l0 and I l. As shown, the work W is supported between a suitable chuck I3 xed to the upper end of 'a work spindle I4 and a center l5 carried by a tailstock I6 slidably supported on vertical ways l'l and I8 on the work head C and the hob H is carried by a, tool spindle 20 rotatmotor 2| is operatively connected by a flexibleV ably supported in the tool or hob head D. i The work and tool spindles I4 and 20, respectively, are geared together and driven from a reversible electric motor 2l, hereinafter referred to as the cut motor. A relative feed movement between the work and hob spindles is elected. by moving the vwork. head C vertically by means of a lead screw 22 geared to the work spindle drive in a manner hereinafter speciiically described. The machine also includes means, such as the high speed reversible electric motor 23 operatively connected to a nut 24 with which the lead screw 22 cooperates `for rapidly elevating 'or1lowe1ing the work head C to bring the work W up to or down to the hob H and/or to return the work head to its starting position after the cutting operation has `been completed and the finished piece removed,

Insofar as the mechanical features of the machine shown are concerned, they are similar to those shown in the aforesaid Patent No. 2,307,428 and will not be herein described in detail. Sufce it to say that the work and tool spindles I4 and 20, respectively, are geared together and operatively connected to the cut motor 2l The cut drive connection, designated generally as 25, to a horizontal shaft 2B, the forward splined end of which shaft projects into the hob head D. The shaft 25 is rotatably supported in the frame B by an anti-friction bearing 21 and the hub 28 of a gear 30, which gear is in turn rotatably sup.. ported by an anti-friction bearing 3l in a member 32 fixed to the frame B. The forward end of the shaft 2B is rotatably supported in the hob head D by a gear 33 splincd to the shaft 26 and rotatably supported in the hob head by an antifriction bearing 34. The gear 33 is continuously in mesh with a gear 35 fixed to one end of `a short shaft 35 rotatably supported in the adjustable member 31 of the hob head D, the opposite endof which shaft is provided with a gear 38 continuwhich projects forwardly through a partition 4i in the work head C and into a gear box or com part-- ment designated generally by the reference charu acter 43. The splined portion of the shaft 43 permits the Iwork head C to be moved vertically. The shaft 46 is operatively connected to a horizontal shaft 50 through the medium of the work spindle drive change gears E, the driving and driven gears 5I and 52 of which are keyed to the ends` of the shafts 46 and 59 respectively. The shaft 50 is rotatably supported in an adjustable cradle and'is provided with a worm 54 continuously in mesh with a worm wheel 55 keyed to the work Y spindle I4.

The work head C is moved in timed relation to the rotation of the tool and work spindles during the cuttingoperation by the lead screw 22 previously referred to, operatively connected to the work spindle drive by a worm wheel Si! keyed to the upper end thereof, which worm wheel is continuously in mesh With a worm 6! xed to a horizontal shaft 62 rotatably supported in the work head D. The shaft 62 projects through the partition 4l' into the gear box i3 where it is operatively connected to the shaft 56 by the feed change gears F, the driving and driven gears 64 and 65, respectively, of which are fixed to the shafts 53 and 62, respectively.

AItv will be apparent from the foregoing that the direction of feed with respect to the direction of rotation of the tool and lwork spindles can be reversed by either inserting or removing an idler gear in the feed change gears F and that the direction of feed and the direction of rotation of the work spindle I4 can be reversed with reference to the direction of rotation of the tool or hob spindle 2G by inserting or removing an idler gear from the work spindle drive change gears E. For the purposes of permitting the use of various change gears, idlers, etc., in the work spindle drive change gears E and the feed change gears E suitable spiders or gear supporting members 66 and 61 are provided. The particular arrangement. shown in the present instance forms no part of this invention and is similar to that disclosed in the aforesaid Patent No. 2,307,428.

The traverse motor 23 is operatively connected to the nut 24 with which the lead screw 22 cooperates by a worm and worm wheel combination comprising a worm I0 fixed to a shaft 'H' operatively connected by a coupling member 'l2 to the armature shaft 'I3 of the motor 23. The worm 10 is continuously in mesh with a worm wheel 'I4 cut in the periphery of the nut 24. The weight of the `work head C is carried by a thrust bearing-' interposed between the lower side of the nut 24 and the bottom of an aperture in a bracket 16 which supports the same. The bracket T6 is detachably connected to the base A of the machine.

According to the provisions of the present invention, the worm 'l0 and worm wheel 'i4 com-` bination is not of the self-locking type and supplemental means is providedfor holding the nut 24 stationary during rotation of the lead screw 22 to produce the feed movement between the work and tool spindles I4 and 2li, respectively. As shown, this means is an electric solenoid-operated brake, designated generally by the reference character G, connected to the left-hand projecting end of the armature shaft 73 of the motor 23 as viewed in Fig. 2. The solenoid-operated brake G comprises two movable brake shoes 8U and 8l adapted to engage a brake drum 82 fixed to the armature shaft 'i3 of the motor gagement with the brake drum 82 by a compression spring 83 interposed between the right-hand shoe 30 and a member B6 secured to the end of a'rod 85 pivotally connected to the shoe 8l. The brake'shoes are actuated t0 disengage the brake drum 82 and thus release the brake on the armature shaft 13 by an electric solenoid 84 connected with the electric control of the machine` in a manner hereinafter described. When the solenoid brake G is released, the nut 24 and in turn the armature shaft i3, etc., are free to rotate and rotation of the'lead screw 22 will not effect any relative rotation f therebetween and the nut 24.

Fromthe foregoing description, it will be apparent that the relative feed movementl between the work and tool spindles can Vbe interrupted without stopping the relative rotation between the spindles by-energizing the solenoid 85 to release the brake, which according to the provisions of the present invention, is accomplished automatically at a predetermined po-int in the relative movement between the spindles. The control for the solenoid 8E of the brake is so arranged thatcthe brake is released whenever the motor 23 is connected to the power source, as will be hereinafter described.

The `machine is started by pushing a start push button switch located on 'a switch panel Si mounted on the side of theV machine, whereupon the traverse motor 23 operates to rotate the nut 24 at a high rate of speed and in such a direction thatV the work W is rapidly moved toward f the hob H. JustY prior to the time the work W engages the hob H a switch 92 located on the left-hand side of the column B is actuated by an adjustable stop 93 carried by the work head C, stoppingj the rapid traverse motor VZ3, and starting the cut motor 2l. The up and down limits of movement of the work head C are controlled by an electric switch 94 actuated by adjustable stops 95 and 9,6 also carried by the work head C. The stop 95 ycontrols-the downward limit of movement of the work head C and the stop 9S the upward limit of movement. Actuation of the switch 94 during the rst movement by either of the stops 95 or S6, energizes the solenoid 84 of the brake G but a timing release maintains the motor 2| energized for a predetermined period of time the duration of which period is sufficient for the work spindle to make at least'one complete revolution. As previouslyv stated, the machine ofthe present invention is exceptionally' adapted for cutting splines on. a shaft and the purpose of having the work spindle make a complete revolution after the feed of the work cut has stopped is to have all of the splines end at the same longitudinal point along the shaft. After the shaft has been cut and removed7 the work head C is returned to its starting position by again depressing the start push buttonlswitch 90. For safety, a normally closed travel limit switch Sg'l is provided, see wiring diagram. YThe limit switch ,91 is located on the The brake shoes are normally held in enaoedeov right-hand side of the eoliimn B and does not snow on Figs. rand 2 of the drawings, but is so mounted and adapted to be opened by a xed stop carried by the work head C that the work head C cannot beraised nigh enough tc damage the machine even ,t though the other switches fail. The control system for the machine is so arranged that the cycle or operations of the machine can `be started with the work head C in either of its `mirmally extreme positions. In the embodiment shown the direction in which the cycle ofcperations is eected is controlled by drum controllers J and `Siinounted on the switch panel 9|. The drum controllerJ has two positions,` designated up and down respectively. When the drum controller J is set in theup position, the circuits to the switches 92 and 94,

. etc., are set up to execute the cycle of operations wherein `the work head C moves in `an upward direction to effect the feed, Aandvice versa. The drum controller K has two positions, designated forward and .reverse respectively. When the controller isset in the"forward" position, the direction of rotation of the hob spindle is such that' the hob moves up in front, that is in a clockdirection as viewed in Fig. l, and vice versa. Since the feed can be effected in either direction of movement `of the Work head C and since the cut motor which drives the hob can be reversed, Vit will be apparent that either climb hobbing or conventional hobbing can be effected in either direction merely yby setting the drum controllers J ,and K in the selected positions Vand by so se- 4looting the change gears that the feed. is in the proper direction. l

The motors 2| and 23 as shown are of the reversible three-phase alternating current type and are "adapted to be connected and disconnected "from power lines 98, 99 and |00 `which in the present instance `constitutes a power source for the machine, by solenoid actuated motor controls and |02 of commercial design mounted within the column B. The controls for the motors 2| and `23 anda solenoid operated brake G, etc., can best be described with reference to the operation of the machine. For the present purposes lit is confsideredslifcientto described but one of the Various `cycles of operation which the machine shown is'capable lof performing :and the cycle selected `is the one wherein conventional hobbing is effected and the work head moved in a vertical upwardly direction to produce the relative feed movement Ibetween the tool andwork With the drum controller J set in its normal position, .the drum controller K set in its for- Ward position, and the change gears as shown in `the drawings, tthe hob will rotate in a clockwise direction 'as viewed in Fig. il, when the machine is started and the work head C will move in an upwardly ldirection to eflect the relative feed movement between the tool and work. At the be- `ginning `:of `the cycle of operations the work head l `C is in its down position. After the work blank,

in the present instance a shaft `W to be splined fat one end, has been positioned in the work head from the line 99 through the overtravel limit.

switch 91, wire ||0, normally closed stop push bttnvswitch III, wire II2, contacts |05, |06,'

wire I7I 3f, operating solenoid I I4 of relay I5, wire 116, contacts Ill-1,` |118 or drum `controller J, wire |20, contacts |2I, |22 of switch 94, wire |23, ,overload contacts |24, |25 for rapid traverse motor 23, Wire |26, overload contacts |21, |28 for cut motor 2| to line |00, energizing the solenoid I |4 of relay H5, Energization of the operating `solenoid I |4 of relay ||5 closes the normally open contacts |30, `|3| thereof, establishing a circuit from the line 99 through the limit switch `91, wire H0, stop push buttonswitcn III, wire |I2, contacts |30, 3|, wire |32, operating solenoid |33 of controller panel IBI, wire 134, contacts |35, |36 of drum `controller J, wire |31, contacts |38, |40 of switch 92, wire IIS, contacts II1, I|3 of drumcontroller J, wire |20, contacts |2I, |22 of switch 94, wire |23, overload contacts |24, |25, wire |26 and overload contacts |21, |28 to line |00. Energization of the solenoid |33 closes the main contacts |4|, |42, |43, |44, |45, |46 for the travel motor 23 connecting the latter to the power lines in such a manner that the motor rotates in a direction to Iraise the work head C. l

When the start'push buttonV switch 90 is released, `the operating solenoid I4` for the` relay ||5 will be momentarily `deenergized dueto the opening of contacts |05, |06 of start push `button switch 90, however, operating solenoid |33 of controller panel IOI will be maintained energized by contacts` |41, |48 thereof which closed simulrtaneously with the contacts |4| to |45, inclusive. This holding or `maintaining circuit is from the line 99 through the overtravel limit switch 91,

wire ||0, stop push button switch IIl, wire ||2, contacts |41, |40, wire |32, solenoid |33, wire |34, contacts |35, |35:` `or drum controller J, Wire I 31,v contacts |38, |49 of switch 92, wire IIS, contacts `I.|1, VI I8 of `drum controller', Wire |20, contacts |2|, |22 of switch 94, wire |23, overload contacts |24, |25, wire |26, and overload contacts |21, |28 to line |00. When the start push button switch isreleased completely, the solenoid |I4 of relay ||5 is lagain energized by the closing of normally closed contacts |03, |04 of start switch 90. 'This circuit is from the line 99 through limit switch 91, wire IIO, stop push button switch |I|, wire II2, contacts |41, |49, controller panel |0I, `wire |32, contacts |03, |94 of start push button switch 90, wire I3, operating solenoid ||4 of relay ||5,' Wire I l5, contacts I I1, I I8 of drum controller J, wire |20, contacts `I2I, |22 of switch 94, wire |23, overload contacts |24, |25, wire |23, overload contacts |21, |28, to'line |90.

`The traverse or travel motor 23 continues to Voperate, raising the work head C until just prior to the engagement of the work W with the hob H at which point the stopl93 on the work head C trips the switch 92, opening the previously closed contacts |38, |40 and closing the open contacts |50, I5I. The opening of contacts |38, |40 of switch 92 breaks the holding circuit for the so-lenoid |33, stopping the rapid traverse or travel motor 23, and'closing of the contacts |50, |5I of rthis switch energizes the operating solenoid |52 of the motor controller panel |02 closing the normally open main contacts |53, |54; |55, |59; |51, |058 and connecting the cut motor 2| to the Apower lines 99, 99 and |00 -in such a manner that 'the motor operates :in a direction to rotate the hob in a clockwise direction as viewed in Fig. `l, and to continue the elevation of the work head C but at a feed rate. The circuit through the voperecting solenoid |52 is from the line 99, through the limit switch 91, wire IIO, stop push button switch III, wire `II2, contacts |30, I3! of relay II5, wire I 32, `normally closed contacts |03, |04

of start push button switch 90, wire I |3, solenoid` |52, Wire |60, contacts I6|, |62 of'drum constroller J, wire |63, contacts |50, of switch 92, wire H6, contacts ||1, ||8 of drum controller J, wire |20, contacts |2I, |22 of switch 94, wire |23, overload contacts |24, |25, wire |26 and overload contacts |21, |28, to line |00.

Upon the energization of the operating solenoid |52 of the controller panel and the closing of the main contacts |53, |54; |55, |56; |51, |58 associated therewith, auxiliary contacts |64, |65 are also closed. The closing of these latter contacts establishes a holding circuit for the operating solenoid |52, control panel |02. This circuit is from the line 99, through the limit switch 91, wire ||0, stop push button switch I, contacts |64, |65, wire ||3, solenoid |52, wire |60, contacts I6I, |62 of drum controller J, wire |63, contacts |50, |5| of switch 92, wire ||6, contacts ||1, I|8 of drum controller J, wire |20, contacts I2 |22 of switch 94, wire |23, overload contacts |24, |25, wire |26 and overload contacts |21, |28 to line |00, The closing of contacts |50, |5| of switch 94 also closes la circuit to solenoid |66 of relay |61 closing the normally open contacts |10 and |1I thereof establishing an auxiliary maintaining circuit from contact |5| of switch 92 to line |00. The circuit for the solenoid |66 of relay |61 is from line 99 through normally closed overtravel limit switch 91, wire |I0, stop push button switch wire I|2, contacts |30, I3| g of relay ||5, wire |32, operating solenoid |66 of relay |61', wire |60, contacts |6|, |62 of drum controller J, Wire |63, contacts |50, |5| of switch 92, wire ||6, contacts ||1, I|8 of drum controller J, wire |20, contacts |2I, |22 of switch 94, wire relay |15, wire |16, closed contacts |11, |18 of selector switch |80 mounted on the control panel 9|, wire |23, overload contacts |24, |25, wire |26, and overload contacts |21, I 28 to line I 00.

` Oper-ation of the cut motor 2| continues until the work blank W is carried to the desired height, whereupon the stop 96 on the work head C actuates the switch 94 to open the closed contacts |2I, |22V thereof and close the contacts |8|, |82. The closing of contacts |8I, |82 of travel limit switch 94 energizes the' operating solenoid |83 of timing relay and the operating solenoid |64 of relay |85. The circuit through the operating solenoid |83 is from the line 99 through the overtravel limit switch 91, wire I |0, stop push :l

button switch wire ||2, contacts |86, |81 -of lay |15, wire |90, contacts |9|, |92 of selector switch |80, wire |93, contacts |94, |95 of drum controller J, wire |96, contacts |8|, |82 of travel limit switch.. 94, wire |23, overload contacts |24, |25, wire |26, and overload contacts |21, |28 to line |00. The circuit throughoperating solenoid |84 of relay |85 is from the line 99 through the overtravel limit switch 91, wire ||0, stop push button switch III, wire ||2, contacts |86, j|81 of relay II5, wire |88, solenoid |84 of relay' |05, wire |91, contacts 200, 20| of selector switch |80, wire |90, contacts |9|, |92 of selector switch |80, wire |93, contacts |94, |95 of drum controller J, Wire |96, contacts |8|, |82 of travel limit switch 94, wire |23, overload contacts |24,`|25, wire |26 and overload contacts |21, |28 to line |00. When the solenoid |84 of relay |85 is energized, it closes a holding or maintaining circuit through (lil normally open contacts 202 and 203 thereof, which circuit, maintains the relay energized. When the contacts |86 and |81 of relay ||5 are Vopened through operation of the timing relay |15, the circuit for the maintaining circuit is from line 99, through overtravel limit switch 91, wire ||0, stop push button switch I||, wire I|2, contacts 202, 203 of relay |85, wire 204, contacts 205, 206 of timing relay 201, wireIBB, operating solenoid |84, relay |85, wire |91, contacts 200, 20| of selector switch 80, wire |90, contacts |9|, |92'of selector switch |80, wire |93, contacts |94, |95 of drum controller J, wire |96, contacts |8|, |82 of travel limit switch 94, wire |23, overload contacts |24, |25, wire |26, and overload contacts |21, 28 to line |00. Energization of solenoid |84 of relay |85 closes the normally open contacts 208, 2|0, 2||2|2 energizing the oper- Hating solenoid 84 for the solenoid brake G, thus allowing the motor shaft of the rap-id traverse motor 23V to turn freely, being driven from the feed screw 22, etc., thus stopping the feed movement of the work head C. The circuit for the operating solenoid 84 of the brake G is from the line 99, through the contacts 2I|, 2|2 of relay |85, wire2l3, solenoid 84, wire 2|4, and contacts 208 2I0 of rlay |85 to line |00.

AfterV tle opening of the closed contacts .|2I, |22 of travel limit switch 94 and the closing of the normally o-pen contacts |8| and |82 thereof, the timing relay |15 maintains the operating solenoid |52 of the control panel |02 energized, thus maintaining Vthe cut motor in operation for a predetermined period of time, which period is at least suflicient to allow the work spindle to make one complete revolution, with the result that all of the splines are ended at the same longitudinal point along the work blank. At the end of the aforesaid predetermined period of time, the normally closed contacts |13, |14 of` the timing relay |15 open, thus breaking the circuit to the operating solenoid ||4 of relay ||5, thereby opening the circuit to the operating solenoid |52 of controller panel |02, thus stopping the motor 2| and the circuit to the oper-ating solenoid |66 of relay |61. Upon the closing of the normally closed contacts 2I5, 2|6 of relay I5, a circuit is closed for the operating solenoid 2|1 of timing relay 201. This circuit is from tire line 99 through the overtravel limit switchV 91, wire ||0, stop push button switch wire ||2, contacts 202, 203 of relay |85, wire 204, contacts 2|5, 2|6, wire 2|9, operating solenoid 2|1 of relay 201, wire |90, contacts |9|,` |92 of selector switch |80, wire |93, contacts |94, |95 of drum controller J, wire |96, contacts |8|, |82 of travel limit switch 94, wire |23, overload contacts |24, |25, wire |26, and overload contacts |21, |28 to line I 00,.

After a predetermined period of time, the timing relay 201 will operate to open its normally closed contacts 205, 206, thereby opening the circuit to operating solenoid |84 of relay |85. The opening of contacts 268, 2|0, 2||, 2|2 of relay will open the circuit to the operating solenoid 04 of the solenoid brake G. The opening of contacts 202, 203 of relay |85 opens the circuit to the operating solenoid 2|1 of timing relay 201. The machine is now ready for the return cycle.

After the work blank is removed, the start push button is again depressed whereupon the rapid the beginning of the cycle of operations.

cuit is established from the line 99 through the limit switch 91, wire I I0, stop push button switch wire II2, contacts |01, |08 of start push button switch 90, wire220, contacts 22|,222 of relay |I5, wire 223, operating solenoid 224 of controller Vpanel |I, wire |93, contacts |94, I65.of drum controller J, wire |95, contacts |8|, |82 of switch 94, wire |23, overload contacts |24, |25, wire |26 and overload contacts I 21, |28, to line |00.

Energization of the solenoid 224 closes the main contacts 225, 226, 221, 228, 229, 230 associated therewith, connecting the rapid traverse or travel motor 23 to the power lines in such a manner that it operates in the reverse direction, that is, in a direction-to lower the work head C. Simultaneously with the closing of the contacts which connect the motor 23 with the power lines, auxiliary contacts 23|, 232 are closed establishing a holding circuit for the solenoid 224 after the start push button switch 90 is released. This holding circuit is from the line 99 through the limit switch 91, 'wire I|0, stop push button switch I I I, wire ||2, contacts 23|, 232, wire 233, contacts 22|, 222, wire 223, solenoid 224,'wire |93, contacts |94, |95 of drum controller J, wire |96, contacts |8|, |82, of switch 94, wire |23, overload contacts |24, |25, wire |26, and overload contacts |21, |28 to line |00. c A f As the work head C` drops, the adjustable stop 93, thereon returns the switch 92 to its original positionlas the stop passes the switch. This reopens the contacts |50, I| and closes the contacts I 38, |40, thus again setting up the circuit with respect to the cut motor 2| which existed at The work head C continues to move down until the switch 94 is tripped by the adjustable stop 95 carried by the work head C. This reopens the contacts |8|, |82, Vstopping the rapid traverse or travel motor 23 and recloses the contacts I2 I, |22, returning the circuit to the rapid traverse or travel motor 23 to its original condition. After a new `work blank is inserted in the work head C, the cycle of operations of the machine can be repeated by again pressingr the start push button switch 90.

If it is desired to stop the feed or vertical movelment of the work head C` at any position in the |62 of drum controller J, wire |63, contacts |50,

I5| of switch 92. wire IIS, contacts ||1, |I8 of drum controller J, wire |20, contacts I2|, |22 of switch 94, wire |23, overload contacts |24, |25, wire |26, and overload contacts |21, |28 to line |00. relay |85 closes the normally open contacts 208, 2 I0 and 2| I, 2|2 thereof, energizing the operating solenoid 84 of the `brake G, thus releasing the brake on the armature shaft of the rapid traverse motor 23, allowing the motor to be driven freely by the lead screw 22, thereby stopping the feed movement of the work head C.

1 If the automatic feed cut-out feature'of the machine is not desired, the machine can be Voperated without it by moving the selector switch Energization of operating solenoid |84 of to its open position. The opening of contacts |11, |18; ISI, |92; and 200,20I of selector switch prevents the circuits to the solenoids |66, |83, |84 and 2I1 of the relays |61, |15, |85 and 201 from closing, and the machine operates in a manner similar to the machine shown in the aforesaid Patent No. 2,307,428.

l When the operating solenoid |84 of relay |85 is deenergized, the solenoid 84 of the solenoid operated brake G is automatically connected to two of the lead wires 234, 235 and 236 which connect the rapid traverse motor 23 to the control panel EBI so that the brake G will be released whenever the rapid traverse motor is operating. As shown, the circuit is from the lead wire 235 through the normally closed contacts 231, 238 or relay |85, wire 2|4, operating solenoid 84 of brake G, wire 2|3, and back through normally closed contacts 240, 24| of relay |85, to lead wire 234. The lead wires 234and 235 are connected to the drum controller J in such a manner that the direction of rotation of the motor is reversed when the drum controller is changed from conventional to climb position andvice versa. The wires from the drum controller J to the motor 23 are designated by the reference characters 242, 243 and are connected to reversing terminals 244, 245 and 246, 241 of drum controller J The wires 234 and 235 are connected to contacts 248 and 249 of the drum controller. rlhe out motor 2| is connected to the main contacts of control panel I 02 by wires 250, 25| and 252. The wires 250 and 25| are connected to contacts 253, 254 of reversing drum controller K and the drum controller is connected to the cut motor by the wires 255 and 256 which, in addition to being connected to the motor terminals, are connected to the reversing contacts 251, 258 and 259, 260 of the drum controller.

`.As previously stated, the machine shown can -be operated so that the cutting operation will be performed in either the conventional manner or in a manner to effect climb hobbing and the cycle of operations can be effected with the feed taking place in either direction and the automatic feedcut-out feature can be had in any of the cycles mentioned, however, it is considered unnecessary to a, complete understanding of the present invention to describe all of these cycles of operations. Both the stat push button switch and the stopy push button switch I I I are of conventional construction and include ferrules whereby the switches may be set with all of the contacts thereof open. When the start push button switch is set in the aforesaid position, the

' machine stops at the point in the cycle of operations where normally the cut motor 2| automatically starts. This feature is useful in setting up the machine. With the stop push lbutton set with its contacts open, the machine cannot be operated.

From the foregoing description of the preferred embodiment of the invention, it will be apparent that a new and improved machine of the type referred to has been provided wherein electrically controlled means is provided for automatically stopping the feed movement between the tool and work spindles without stopping the rota-I tion of the spindles and wherein the rotation of the spindles is stopped after a predetermined period of time. While the preferred embodiment shown has been described in .considerable detail, it is to be understood that the invention is not limited to the particular construction shown and described and it is the intention to cover hereby all adaptations, modifications and uses thereof that come within the practice of those skilled in the art to which the invention relates and within the spirit and scope of the appended claims.

We claim:

l. A hobbing machine of the character described comprising:` a frame; a work spindle; means for rotatably supportingsaid work spindle; a hob o-r tool spindle; means for rotatably supporting said hob or tool spindle; a lead screw member and a cooperating nut member for producing relative movement between said work spindle and said tool spindle; means for rotatably supporting said lead screw member; means for rotatably supporting said nut member; means for holding one of said members against rotation; power actuated means for rotating the other of said members to effect a relative movement between said spindles; means for initiating operation of said power actuated means; and means for automatically rendering said fifth named means inoperative upon said spindles reaching a predetermined relative position.

2. A hobbing machine of the character described comprising: a frame; a work spindle; means for rotatably supporting said work spindle; a hob or tool spindle; means for rotatably supporting said hob or tool spindle; a lead screw vmember and a cooperating nut member for producing relative movement between said work spindle and said tool spindle; an electric motor for rotating said spindles and one of said members to effect a relative movement between said spindles at a feed rate; means for preventing rotation of the other of said members; alreversible electric motor for rotating one of said members in opposite directions to effect relative movementibetween said spindles at a traverse rate; means for effecting operation of said reversible electric motor in one direction whereupon relative movement between said spindles is produced at a traverse rate; means for automatically initiating the operation f said irst named electric motor and discontinuing the operation of said reversible electric motor upon said spindles reaching a predetermined relative position whereupon the relative movement between said spindles is continued at the feed rate;l means for automatically rendering said third named means inoperative upon said spindles reaching a second predetermined relative position; means for rendering said iirst named electric motor inoperative after a predetermined lapse of time; means for subsequently effecting the operation of said reversible electric motor but in such a manner that it operates in a reverse direction whereupon relative movement between said spindles is produced in the opposite direction at a traverse rate; and means for automatically discontinuing the operation of said reversible electric motor upon said spindles reaching their initial relative position.

3. A hobbing machine of the character described comprising: a frame; a work spindle; means for rotatably supporting said work spindle; a hob or tool spindle; means for rotatably supporting said hob or tool spindle; a lead screw member and a cooperating nut member for producing relative movement between said work spindle and said tool spindle, one of said members being adapted to drive the other; an electric motor for rotating said spindles and both of said members, one of said members being driven throughl the other; an electric solenoid controlled brake operatively connected to the member of said members being driven by the other member thereof; a reversible electric motor for rotating one of said members in opposite Adirections'to elect relative movement between said spindles at a traverse rate; means for connecting said reversible electric motor with a power source whereupon relative movement between said spindles is eiected at a traverse rate; means for automatically connecting said irst named'electric motor with a power source, actuating said vbrake to prevent rotation of said member to which it is operatively connected and disconnecting said reversible electric motor from the power source, upon said spindles reaching a predetermined relative position whereupon the relative movement between said spindles is continued at a feed rate; means for automatically rendering said brake inoperative to prevent rotation of said member with which it is operatively connected upon said spindles reaching a second predetermined `relative position; means for automatically disconnecting said first named electric motor from the power source after a predetermined lapse of time; means for subsequently connecting said reversible electric motor with a power source but in such a manner that it operates in a reverse direction whereupon relative movement between said spindles is produced in the opposite direction ata traverse rate; and means for automatically disconnecting said reversible electric motor from said power source upon said spindles reaching their initial relative position.

4. A hobbing machine of the character described compzising: a frame; a work spindle; means for rotatably supporting said work spindle; a hob or tool spindle; means for rotatably supporting said hob or tool spindle; a lead screw member and a cooperating nut member for producing relative' movement between said work spindle and said tool spindle, means for supporti ing one of said members in said frame for free rotation relative thereto whereby it is capable of being driven by the other; an electric motor for rotating said spindles and both of said members; an electric solenoid controlled brake operatively connected to said member adapted to be driven by the other of said members; a reversible electric motor for rotating one of said members in opposite directions to eiect relative movement between said spindles at a traverse rate; means for connecting said reversible electric motor with a power source whereupon relative movement between said spindles is effected at a traverse rate; means for automatically connecting said rst named electric motor with a power source, actuating said brake t0 prevent rotation of said member to which itis operatively connected and disconnecting said reversible electric motor from the power source, upon said spindles reaching a predetermined relative position whereupon the relative movement between said spindles is continued at a feed rate; means for automatically rendering said brake inoperativeA to prevent rotation of said member with which it is operatively connected upon said spindles reaching a second predetermined relative position; means for automatically disconnecting said first namedY electric motor from the power source after a predetermined lapse of time; means for subsequently connecting said reversible electric motor with a power source but in such a manner that it operates in a reverse direction whereupon relative movement between said spindles is produced in the opposite direction at a traverse rate; and means for automatically -disconnecting said reversible electric motor'from said power source upon said spindles reaching their initial relative position.

5. A hcbbing machine of the character described comprising: a frame; a work spindle; means for rotatably supporting said work spindle, a hob or tool spindle; means for rotatably supporting said hob or tool spindle; a lead screw and a cooperating nut for producing relative movement between said work spindle and said tool spindle; means for rotatably supporting said nut in said frame whereby said nut is capable of being driven by said lead screw; an electric motor for rotating said spindles and said lead screw; an electric solenoid controlled brake operatively connected to said nut; a reversible electric Amotor for rotating said nut in opposite directions to effect relative movement between said spindles at a traverse rate; means for connecting said reversible electric motor with a power source whereupon relative movement between said spindles is eiected at a traverse rate; means for automatically connecting said rst named electric motor with a power source, actuating said brake to pre- `vent rotation of said nut and disconnecting said `reversible electric motor from the power source,

upon said spindles reaching a predetermined relative position whereupon the relative movement between said spindles is continued at a feed rate; means for automatically rendering said brake inoperative to prevent rotation of said nut upon said spindles reaching a second predetermined position; means for automatically disconnecting said rlrst named electric motor from the power source after a predetermined lapse of time; means for subsequently connecting said reversible electric motor with a power source but in' such a manner that it operates in a reverse direction whereupon relative movement between said spindles is produced in the opposite direction at a traverse rate; and means for automatically disconnecting said reversible electric motor from said power source upon said spindles reaching their initial relative position.

6. A hobbing machine of the character described comprising; a frame; a hob or tool spindle; means for rotatably supporting said hob or tool spindle in said frame; a work head slidably supported on said frame; a work spindle; means for rotatably supporting said work spindle in said work head; a lead screw member and a cooperating nut member for moving said work head; means for rotatably supporting one of said members in said work head; means for rotatably supporting the other of said members in said frame; means for holding one of said members against rotation; power actuated means for rotating said spindles and the other of said members means for initiating operation of said power actuated means; means for automatically rendering the fifth named means inelective to prevent rotation of said member associated therewith upon said work head reaching a predetermined position;

`and means for subsequently rendering said power actuated means ineffective to rotate said spindles.

7. A hobbing machine of the character described comprising: a frame; a hob or tool spindle; means for rotatably supporting said hob or tool spindle in said frame; a Work head slidably supported on said frame; a work spindle; means for rotatably supporting said work spindle in said work head; a lead screw member and a cooperating nut member for moving said work head; means for rotatably supporting one of said members in said work head and the other of said members in said frame; an electric motor for rotating said spindles and said member rotatably supported in said work head; means for selectively preventing rotation of said member rotatably supported in said frame; a second electric motor for rotating one of said members in opposite directions; means for effecting operating of said second electric motor in one direction; means for automatically initiating operation of said rst named electric motor and discontinuing the op eration of said second electric motor upon said spindles reaching a predetermined relative position; means for automatically rendering the fourth named means inoperative to prevent rotation of said member associated therewith upon said work head reaching a second predetermined position; means for rendering said first means inoperative after a predetermined lapse of time; means for subsequently eiecting the operation of said second means but in a reversed direction; and means for automatically discontinuing the operation of said second means upon said work head reaching its starting position.

8. A hobbing machine of the character described comprising: a frame;'a hob or tool spindle; means for rotatably supporting said hob or tool spindle in said frame; a, work head slidably supported on said frame; a work spindle; means for rotatably supporting said work spindle in said work head; a lead screw member and a cooperating nut member for moving said work head; means for rotatably supporting one of said members in said work head and the other of said members in said frame; an electric motor for rotating said spindles and said member rotatably supported in said work head; means for preventing rotation of said member supported in said frame; a second electric motor for rotating one of said members in opposite directions; means for eiecting operating of said second electric motor; means for automatically initiating operation of said rst electric motor and discontinuing the operation of said electric motor upon said spindles reaching a, predetermined relative position; electric means actuated by the movement of said work head for automatically rendering said fourth named means inoperative to prevent rotation of said member rotatably supported in said frame upon said work head reaching a second predetermined position; means for rendering said rst means inoperative after a predetermined lapse of time; means for subsequently effecting the operation of said second means but in a reversed direction; and means for automatically discontinuing the operation of said second means upon said work head reaching its starting position.

GEO. L. MERRILL. 'rHEoDoRE F. CARLIN. EDWARD J. BAToRsKr.

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