US2487704A - Automatic feed mechanism for grinding machines - Google Patents

Description

New 8, 1949 a. J; GRUENBERG ET AL AUTOMATIC FEED MECHANISM FOR GRINDING MACHINES 7 Sheets-$heet 1 Filed Aug. 12, 1946 UQU S m c E T RN m V ST N NS 1 R GH i0 N m m HR Y B y/mww wwmw ATTORNEYS Nov. 8, 1949 1. .J. GRUENBERG ET AL AUTOMATIC'FEED MECHANISM FOR GRINDING MACHINES 7 Sheets-Sheet 2 Filed Aug 12, 1946 INVENTORS LGRUENBERG REIN O H. MUSTONEN ATTORNEYS Nov. 8, 1949 J. GRUENBERG ET AL 9 3 AUTOMATIC FEED MECHANISM FOR GRINDING MACHINES Filed Aug. 12, 1946 7 Sheets-Sheet 3 LLgL S2 Ll.-

1N VEN TORS work J.GRUENBERG BY Rsmo H. MUSTONEN WW MMWM ATTO RNEYS Nov. 8, 1949 Filed Aug. 12,

l. J. GRUENBERG ET AL AUTOMATIC FEED MECHANISM FOR GRINDING MACHINES 7 Sheets-Sheet 4 T INVENTORS IVOR J.GRUENBERG BY REINO H.MUSTONEN ATTORNEYS Nov. 8, 1949 All I. J. GRUENBERG ET AL AUTOMATIC FEED MECHANISM FOR GRINDING MACHINES Filed Aug. 12, 1946 7 Sheets-Sheet 5 INVENTORS \VOR J. GRU EN BERG W I BY R EINO H. MUSTONEN ATTORNEYS Nov. 8, 1949 1. J. GRUENBERG ETAL AUTOMATIC FEED MECHANISM FOR GRINDING MACHINES Filed Aug. 12, 1946 7 Sheets-Sheet 6 DU 8/ J h mu if Q INVENTORS IVOR J.GRUENBER5 y REINO HMUSTONEN ATTORNEYS Nov. 8, 1949 1. GRUENBERG ETAL AUTOMATIC FEED MECHANISM FOR GRINDING MACHINES '7 Sheets-Sheet '7 Filed Aug. 12, 1946 X aiL a INVENTORS QGE IVOR J.GRUENBERG REINO H.MUSTONEN ATTORNEYS Patented Nov. 8, 1949 AUTOMATIC FEED MECHANISM FOR GRINDING MACHINES Ivor J. Gruenberg, Pleasant Ridge, and Reino H. Mustonen, Detroit, Mich., assignors to The Gear Grinding Machine Company,

Hamtramck,

Mich., a corporation of Michigan Application August 12, 1946, Serial No. 690,024

The invention relates to automatic feed mechanisms for grinding machines and more particularly to grinding machines of the type used in the grinding of gears with formed grinder wheels.

It is the object of the invention to obtain a construction which is applicable to any grinding machine and functions to automatically advance the grinder wheel into the work in successive steps.

It is a further object to accurately control this advancement so that the successive steps thereof are neither too large nor too small and will terminate when the work is of finished size.

It is a further object to obtain a construction which does not in any way interfere with the manual adjustment of the grinder wheel into or out of operative relation to the work.

It is a further object to utilize certain elements of this manually operable adjustment mechanism as essential elements of the automatic feed. With these and other objects in view the invention consists in the construction as hereinafter set forth.

In the drawings:

Fig. 1 is a front elevation of a grinding machine to which my automatic feed mechanism is applied;

Fig. 2 is a plan view of a portion of the machine;

Fig. 3 is an elevation similar to Fig. 1 illustrating only the automatic feed mechanism and being partly in section;

Fig. 4 is a vertical central section on line 4--4, Fig. 3, illustrating the step by step automatic feed mechanism;

Fig. 5 is a section on line 5-5, Fig. 4;

V Fig. 6 is a vertical central section through the metering means and on line 6-6, Fig. 2;

Fig. '7 is a plan view of Fig. 6;

Fig. 8 is an elevation of the construction shown in Fig. 4 viewed from the right end thereof;

Fig. 9 is a diagrammatic view illustrating the hydraulic operating system;

Fig. 10 is a section substantially on line l0l0,

Fig. 9, illustrating the locking valve for the hydraulic operation mechanism.

While the automatic feed mechanism is ap plicable to various types of grinding machines,

it is specifically shown in connection with a ma- I chine designed for the grinding of gears. Generally described, this machine comprises a bed member A on a portion of which is mounted a work support including a head stock B and tail stock B having centers B for engaging an arbor nut G engaging the same.

on which the gear to be ground is mounted. There is also an indexing mechanism 13 (not shown in detail) for periodically rotating the arbor step by step. On another portion of the bed A is mounted for longitudinal reciprocation a table C. This table carries a grinder wheel D which is mounted on a head E vertically adjustably secured to a column F. As the specific construction of this grinder wheel mounting is not a part of the instant invention, it will be suificient to describe the means employed for manually vertically adjusting the head E on the olumn F so as to move the grinder wheel toward or from the work. This comprises a vertically extending screw-threaded rod G and a The nut is attached to the head E and the rod is rotatively mounted on the column F. A gear wheel H at the upper end of the screw-threaded rod is in mesh with a gear wheel H on a parallel shaft H which latter is adapted to be rotated by a hand wheel H at the front of the column through the medium of a horizontally extending shaft H and beveled gear wheels H Thus, the operator can raise or lower the grinder wheel D as required to place the same in operative relation to the work.

The mechanism above described may be used not only for the initial adjustment of the grinder wheel into operative relation to the work but also for manually feeding said grinder wheel into the work step by step. Where it is so used the screw-threaded rod G is held against axial movement and, consequently, will impart movement to the head E only, by its rotation in the nut G. However, in the automatic feed the rod G is moved axially by a mechanism now to be described,

Automatic feeding mechanism The rod G at its upper end is journaled in a bearing G which permits axial as well as rotary movement of said rod. At its lower end it extends into a housing I mounted on the table C which housing also contains the mechanism for imparting axial movement to the rod. This mechanism includes a member J which is swiveled upon the rod by end thrust roller bearings J, J These bearings prevent any relative axial movement between the rod G and the member J while permitting free relative rotation. The member J is axially slidable within a cylindrical bearing I in the housing I and is provided centrally with a depending portion J which is connected by a wrist pin K with a bifurcated connecting rod member K. The lower portion of the member K is apertured for the passage therethrough of a horizontal shaft L which is journaled in bearings M, M within the housing I. The shaft L has an eccentric portion L on lWhiCh the member K is mounted by radial .and end thrust roller bearings K Thus, the rotation of the lshaft Lin the bearings M and M will through the eccentric L and connecting rod member K impart .an axial movement to the member J and shaft G. Beyond the bearing M the shaft i-L has .a concentric portion L on which is mounted a pinion N. The latter is in mesh with arack member N which has on opposite (ends thereof piston portions N, N engaging hydraulic lcylinders and O which are mounted on opposite :sides .of l.

the casing I by bolts 0 Afurther extension of the shaft L has fixedly mounted thereon a tripper P and adjacent thereto a rotatively adjustable tripper P. These function to operate limit switches -.controll-ing the operation of hydraulic valves which will later be :described. Finally at the end of the shaft L beyond the portion ,L thereof there is mounted a radiusarm Q.

Before :further description of the apparatus, it may :be stated that the .feeding :movement of the grinder wheel is effected .by an .axial movement of the screw-threaded ,rod G which, in turn, is accomplished .by a rotation of the shaft L causing "the eccentric portion L thereof to move the con- .necting rod K :and member J. The rotation of the shaft L is accomplished by a movement of the pistons N and N in the hydraulic cylinders .0 and O, which movement .is controlled by admission of hydraulic fluid to one of said cylinders and expulsion of fluid :from the other cylinder.

Consequently, the amount of feeding movement must be controlled by accurately :metering the fluid entering-and leaving thecylinders O-and O.

Hydraulic operating system Generally described the hydraulic operating system includes a source-of hydraulic fluid under pressure, a valve controlling the admission of fluid alternatively .to the .cylinders -O and O, :a imeteri-ng means connected to .the cylinder 0 -:operating .to successivelyleject predetermined volumes of fluid therefrom under pressure of fluid :admitted to .the cylinder .0, and ,a valve controlling thesuccessive-operations of said metering means. More specifically, the system includes a tank :R for the fluid, a pump B, operated by an electric motor R ior propelling the fluid from the tank through an'outgoing conduit 8 .and a relief valve R which :returns the unused fluid to the tank while maintaining a predetermined (constant pressure on the line S. The line 8 has a branch s extending to the cylinder 0 and a second branch S leading to the metering device U. In theline-S is an electromagne'ticallyoperated valve "T and in the branch S an electromagnetically operated v-alve'I". A'conduitS extends from the cylinder 0 to the metering device and in this conduit is "a :normally .closed and locked check valve V. The valve'T normally opens the con- 'duit S to maintain hydraulic pressure on the flu d in the "cylinder 0 :but in another position ot said valve, fluid is exhausted from the cylindero" to be returned to the tank R while pressure fluid is supplied through a conduit S 'to the cylinder 0. ncc' eok valve V in this conduit prevents movement therethrough in the opposite direcition. The valve 'T normally opens the branch :conduit "S to supply fluid through a port on S thered'fito oneen'dof theovlin der ofithe metering device U (as will be hereinafter explained), While :rgylinder U..

- \of .the cylinder.

in another position of the valve T, the conduit portion S will be connected to an exhaust conduit S returning fluid to the tank. In the latter position of the valve T the branch conduit S is connected .toa conduit .s leading to the check valvevzandiunctiorflng to unlock and open said valve. There is also a conduit S leading from the conduit portion 8 to the conduit S but containing a check valve V which prevents movement of fluid itherethrough in reverse direction. In the normal position of the valve T, both the conduits is and .S .areconnected with the exhaust conduit -.S

.Metering means stop :is preferably formed by a rod having a threaded .portion U engaging a correspondingly threaded ,portion .in.a head U atone end of the The conduit 5* connects with the end of the cylinder containing the stop U 1, While the conduit ,S .is connected to the opposite end .Thus, normally pressure .fluid in .therconduits S and .8 holds the ,piston 11 against the .stop U Locking check valve The .check valve .V illustrated in "Fig. has a spring a ,for normally holding the valve seated. There is, however, a piston 12 in a cylinder 0 con- .nected .to the conduit Si, and this piston when iaotuatecl will .press .arod 11 against said valve to unseat the same.

Operation The operation of the hydraulic system as thus .far described is as follows. Fluid under pressure fills both of the cylinders O and -O to press against the pistons N and N "therein and hold ""the rack member N against movement. This stationary position of the parts is assured as the check valve Yis lockedirom opening which provents any escape of fluid from the cylinder 0, while the cylinder 0 is in open communication with the conduit S containing the pressure ffluid. Assuming that the valve T is operated, the valve T remaining in normal position, this will first connect the conduit S with the conduits thereby unseating the check va'JVeV. ,Also, the conduit S will be connected -.to the exhaust conduit S Consequently, .the piston is free to move in .the cylinder U under pressure of expelled 'from the cylinder'Oend.passinginto the metering device through the iconduits and open check valve V. Suchexpulsion .irom the cylinder 0 is caused by the pressure of fluidin the cylinder 0 which .actuates the pistons 1N .and N and moves the rack N .a corresponding distance. If the valve 7 1T .isthen restored tonormal position, the valve V will be closed and locked and pressure .fiuid .willenterthemetering-cylinder through the con- Eduit S :returning the piston U to .its position against the stop U and expelling fluid from the opposite sideof said piston through the conduit 1S and check valve V into the exhaust conduit S It is, therefore, apparent that .each actuation .of the valve T will result in the expulsion of a measured volume of fluid from the cylinder O and .a corresponding movement of the pistons N .and N and rack N .The latter will actuate the .pinion N which .will rotate the shaft L causing the eccentric L and connecting rod K to reciprocating table.

pull downward the member J and rod G. This will feed the grinder wheel into the work a predetermined amount and in successive operations of the valve T the grinder wheel will be fed step by step to a predetermined limit. The valve T will then be operated (through control means hereinafter described) which will connect the cylinder with the pressure line S and the cylinder 0' with the exhaust thereby returning the rack N and the mechanism connected therewith to normal position.

Control mechanism In the grinding of gears by formed grinder wheels as heretofore practiced, the relative reciprocation of the work and grinder wheel will move the latter through an interdental space of the gear to fashion the teeth on opposite sides thereof. In one method. the gear is indexed after each reciprocation to register another interdental space with the grinder wheel and this is continued through a plurality of cycles until the finished size is attained. In another method the grinding of the teeth is completed at one point of registration before indexing to bring another pair of teeth in registration. Our improved. automatic feed mechanism may be used with either method but preferably and, as specifically illustrated and described, the latter method is used. This has the advantage of expediting the work as it reduces the number of indexing operations to not more than the number of teeth.

' The control mechanism, which is preferably employed, includes in addition to the hydraulic operating system previously described a plurality of electromagnetic limit switches and actuating members therefor. These are diagrammatically shown in Fig. 9 and. to avoid confusion, electrical connections are indicated in dotted lines. The

table or carriage C is recinrocated by hydraulic 1 means forming no part of the instant invention and, therefore, not illustrated in detail. However, it includes a reversible hydraulic valve ill which is operated by a pair of dogs X and X adjustably mounted on the table to determine the amplitude of reciprocation. The electromagnetically operated hydraulic valves T and T are controlled by limit switches some of which are operated by the trippers P and P and others by dogs on the More specifically. the valve T is operated by a pair of limit switches W and W mounted on the bed A and a pair of cooperating dogs X and X adjustably mounted on the table. These dogs are so positioned that after the grinder wheel has cleared the work at each 7 end of the reciprocatory movement of the table one or the other of the dogs X and X will operate its corresponding limit switch to energize the electromagnet or solenoid of said valve. At the beginning of the return stroke of the table the magnet is de-energized so that it remains energized for only a brief interval. The operation of the valve T is primarily controlled by the tripper P in conjunction with a limit switch W operated thereby at a predetermined point in the rotation of the shaft L counterclockwise (Fig. 9). The closing of the limit switch W energizes an electromagnet which withdraws the dog X so as to permit a further movement of the table C be ore reversing the same. As shown. the dog X is pivotally mounted in a housing member X (not indicated on Fig. 9) and is operated by a solenoid therein when the latter is energized. The member X also carries a dog X spaced from the dog X and performing a similar function when the per P is rotatively adjustable.

latter is withdrawn. In other words, it reverses the direction of travel of the carriage C after its longer movement. This reversal does not, however, immediately occur for the longer movement of the table causes the dog X to operate a limit switch W which temporarily renders the reversing valve I0 inoperative so that the table remains stationary. There is also an adjacent limit switch W operated by the dog X which starts in operation the indexing mechanism H (not shown in detail). Before the completion of the indexing operation a switch [2 is operated thereby to energize the solenoid of the valve T. This, as previously described, will connect the cylinder Owith the pressure line S and the cylinder 0 with the exhaust thereby actuating the rack N in the reverse direction and rotating the shaft L clockwise back to its initial position. Finally, at the completion of this clockwise movement the tripper P actuates the limit switch W which de-energizes the magnet of the valve T thereby completing the cycle.

total amount of the automatic feed As previously described, the trippers P and P are mounted on the shaft L. The tripper P is keyed in fixed position on the shaft but the trip- It is normally locked in its adjusted position by serrated adja cent faces on the members P and P and a handled locking nut P engaging a threaded portion of the shaft. The member P is also provided with a handle P so that by loosening the nut P the tripper P may be drawn out of engagement with the tripper P and adjusted to be in the desired angular relation to the latter. Thus, the relative adjustment of the trippers P and P determines the total angular adjustment of the shaft L and correspondingly the total depth that the grinder wheel will be automatically fed into the work. The tripper P is so located on the shaft L as to actuate the limit switch W when the lid eccentric L is at or near its lower dead center. The tripper P' is adjusted on the shaft L so that when the latter is turned to engage said tripper with the limit switch W the tripper P will be turned from its limit switch W through a pre determined included angle. This determines the total feed of the grinder wheel from it initial to its final position. It will be obvious that the successive removal of equal volumes of fluid from the cylinder 0 by the metering device U will produce equal angular adjustments of the pinion N and shaft L but the vertical adjustment of the rod G will be varied. For instance, if the eccentric F of the shaft F is in its initial position at from the dead center, this will produce the maximum vertical movement of the rod G for a given volume of fluid and in successive steps the vertical adjustment will be progressively diminished. This produces a desirable effect in grinding as the finishing cuts should be less in depth than at the start. If, however, it is desired to change this ratio, it may be accomplished by the following means.

Adjustment of metering means within the cylinder U.

gas-7,704

rod U Therefore, a rotation of this cap will turn the rod U which by reason of its threaded engagement with the head U will move it axially The cap may be calibrated to indicate the change volume by such rotary adjustment.

Automatic adjustment of metering means In addition to .the manual adjustment for the metering means there is provided automatic operating adjustment means of the following construction. The portion ,of the rod U which projects beyond the cap U engages .a bifurcated bearing U and between the furcations .of this "hearing a pinion U is ,mounted on .said rod. A

' a nut Q engaging a threaded outer end portion 0f said pin. Asleeve'Q on the pin between the .nut Q and arm Q forms a pivot connection to the .outer end of the rack bar U so that by adjusting the pin :Q it may be placed at any .desired radial distance from the center of the shaft L and pretera'bly alternatively on opposite sides of said center. The rack U may be disengaged from the pinion U by a handle U threaded-1y engaging a bearing at the .outer end of the strap U and having .a swivel engagement with a c0u- V pling member U 3. The latter has a finger U engaging a longitudinal channel in the rack bar so that said rack bar may be withdrawn from the pinion and reengaged with the same by manipulation of the handle U This permits of making any desired adjustment of the pin Q and also of arranging the radius .arm U in any desired angular relation to the strap U Thus, the .step by step :rotation hi the shaft L will communicate rotary movement to the stop rod U to Change the length -of free travel permitted to the piston. This will change the volume of fluid ejected from the =cylinder O andcorrespondi-ng-ly change the axial movement of the feed screw G. F

What we claim as our invention is:

1. A feed mechanism comprising a nut connected with the member to be fed, a feedscrew engaging said nut, means for manually rotating said screw, a member rotatable about an axis transverse to that of said screw and having an eccentric portion, a connection between said eccentric portion and said feed screw includin a swivel permitting independent rotation of the latter while resisting independent axial movement thereof, a pinion on said rotatable member, a rack intermeshing with said pinion, a hydraulic cylinder and piston motor for actuating said rack, and fluid metering means associated with said hydraulic motor to operate the :same successively step by step.

2. A feed mechanism comprising a nut connected with the member to be fed, a feed screw engaging said nut, :means 'for manually rotating said screw, .a member rotatable about an axis transverse to that of said screw and having an eccentric portion, anon-nection between said eccentric portion and said feed screw including a swivel permitting independent rotation of the latter while resisting independent .axial movement thereof, a pinion .on said rotatable member, .a rack intermeshing with said pinion, pistons at opposite ends of said rack, hydraulic cylinders with which said pistons are engaged, means for supplying fluid under pressure to one of said cylinders, and means for successively ejecting metered volumes of fluid from the other of said cylinders whereby said rack is actuated step by step to communicate a corresponding step by step movement to said feed screw.

3. A feed mechanism comprising a ,nut connected with the member to be fed, a feed screw engaging said nut, means for manually rotating said screw, a member rotatable about an :axis transverse to that of said screw and having an eccentric portion, a connection between said eccentric portion and said feed screw including a swivel permitting independent rotation of the latter While resisting independent axial movement thereof, a pinion on said rotatable member, a rack intermeshing with said pinion, pistons at opposite ends of said rack, hydraulic cylinders with which said pistons are engaged, means for supplying fluid under pressure to one of said cylinders, means for successively ejecting metered volumes of fluid from the other of said cylinders whereby said rack is actuated step by step to communicate a corresponding .stepby step movement to said feed screw, and means .for periodically reversing the direction of fluid in said .cylinders to return said rack and feed screw to their initial positions.

4. In a grinding machine, the combination with a. work holder, a grinder wheel and means for relatively reciprocating the same to effect the grinding of the work, of automatic means for relatively feeding said grinder wheel and .Work holder towards or from each other comprising a ,nut connected with the member to be fed, a feed screw-engaging said nut, means for manually rotating said screw, a member rotatable about an axis transverse to that of said screw and having an eccentric portion, a connection between said eccentric portion and said feed screw including a swivel permitting independent rotation of the latter while resisting independent axial movement thereof, a pinion .on said rotatable member, a rack intermeshing with said pinion, a hydraulic motor for actuating said rack alternatively in opposite directions, fluid metering means associated with said hydraulic motor to operate the latter successively step by step, and means operated by the relative reciprocation of said work holder and grinder wheel and between successive reversals thereof for actuating said metering means to feed said grinder wheel one step.

5. In a grinding machine, the combination with a work holder, a grinder Wheel and means for relatively reciprocating the same .to effect the grinding of the work, of automatic means for relatively feeding said grinder wheel and work holder towards or ,from each other comprising a nut connected with the member to be fed, a feed screw engaging said nut, means for manually rotating said screw, a member rotatable about an axis transverse .to that of said screw and having an eccentric portion, a connection between said eccentric portion and said feed screw including a swivel permittingi-ndependen-t rotation of the latter while resisting independent axial movement thereof, .a pinion on said rotatable member, a rack intermeshing with said pinion, a hydraulic motor for actuatingsaid rack alternatively in opposite directions, fluid metering means associated with said hydraulic motor to operate the latter successively step by step, means operated by the relative reciprocation of said work holder and grinder wheel and between successive reversals thereof for actuating said metering means to feed said grinder wheel one step, and means operating after a predetermined feeding movement of said grinder wheel for reversing said motor to return said Wheel to its original position.

6. In a grinding machine, the combination with a work holder, a grinder wheel, means for relatively reciprocating the same to effect the grinding of the work and an indexing mechanism for said work holder, of automatic means for relatively feeding said grinder wheel and work holder towards or from each other comprising a nut connected with the member to be fed, a feed screw engaging said nut, means for manually rotating said screw, a member rotatable about an axis transverse to that of said screw and having an eccentric portion, a connection between said eccentric portion and said feed screw including a swivel permitting independent rotation of the latter while resisting independent axial movement thereof, a pinion on said rotatable member, a rack intermeshing with said pinion, a hydraulic motor for actuating said rack alternatively in opposite directions, fluid metering means associated with said hydraulic motor to operate the latter successively step by step, means operated by the relative reciprocation of said Work holder and grinder wheel and between successive reversals thereof for actuating said metering means to feed said grinder wheel one step, means operating after a predetermined forwarding movement of said grinder wheel for stopping said reciprocation, operating said indexing mechanism and reversing said motor to return said grinder wheel to its original position, and means operated by the return of said grinder wheel for again reversing said motor and starting said reciprocation.

7. A feed mechanism comprising an axially movable member connected with the member to be fed, a member rotatable about an axis transverse to that of said axially movable member and having an eccentric portion, a connection between said eccentric portion and said axially movable member, a pinion on said rotatable member, a rack intermeshing with said pinion, pistons at opposite ends of said rack, hydraulic cylinders with which said pistons are engaged, means for supplying fluid under pressure to one of said cylinders, and means for successively ejecting metered volumes from the other of said cylinders, whereby said rack is actuated step by step to communicate a corresponding step by step movement to said axially movable member.

8. A feed mechanism comprising an axially movable member connected with the member to be fed, a member rotatable about an axis transverse to that of said axially movable member and having an eccentric portion, a connection between said eccentric portion and said axially movable member, a pinion on said rotatable member, a rack intermeshing with said pinion, pistons at opposite ends of said rack, hydraulic cylinders with which said pistons are engaged, means for supplying fluid under pressure to one of said cylinders, means for successively ejecting metered volumes of fluid from the other of said cylinders whereby said rack is actuated step by step to communicate a corresponding step by step movement to said axially movable member, and means for periodically reversing the direction of fluid in said cylinders to return said rack and axially movable member to their initial positions.

IVOR J. GRUENBERG. REINO H. MUSTONEN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,022,542 Flygare et al. Nov. 26, 1935 2,068,529 Baldenhofer Jan. 19, 1937 2,101,383 Asbridge Dec. '7, 1937 2,411,456 Orcutt Nov. 19, 1946

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