US2924915A - Automatic feed mechanism for grinding machines - Google Patents

Description

Feb. 16, 1960 M. l. RUDNICKI 2,924,915

AUTOMATIC FEED MECHANISM FOR GRINDING MACHINES Filed Jan. 15, 1957 5 Sheets-Sheet 1 "*N 4 '0 1| 1 52 M]? I k 1.5 4 l 1-; g A 2'9 v 2. Z I 6 1 2 A u. i Y m x M Q 1 U E a 2 I I h m: '1 I N1 51 If v A I )7 Q I 5 "2: VINVENTOR. N MARK memzusz RUDNIGKI ATTORNEYS Feb. 16, 1960 M. 1. RUDNIQKI 2,924,915

AUTOMATIC FEED MECHANISM FOR GRINDING MACHINES Filed Jan. 15, 1957 s sheets sheet 2 INVENTOR.

MARK IRENEUSZ RUDNICKI ATTORNEYS Feb. 16, 1960 M. l. RUDNICKI AUTOMATIC FEED MECHANISM FOR GRINDING MACHINES Filed Jan. 15, 1957 a Shets-Sheet :s

INVENTOR. MARK lRENEUSZ RUDNICKI BY g ATTORNEYS/ AUTOMATIC FEED MECHANISM FOR GRINDING MACHINES Mark Ireneusz Rudnicki, Harper Woods, Mich., assignor,

by mesne assignments, to Ex-Cell-O Corporation, Detroit, Mich,, a corporation of Michigan 4 Application January 15, 1957, Serial No. 634,185

Claims. c1. 51-165) The invention relates to automatic feed mechanism for form grinding machines of the type forming the subject matter of US. Patent No. 2,487,704, Ivor J. Gruenberg and Reino H. Mustonen, issued November 8, 1949. This construction comprises essentially automatic means operating during the work grinding cycle for intermittently feeding the grinder'wheel into the work by predetermined amounts, which continues until the work is fashioned to size and form. More specifically, a carriage on which the grinder wheel is mounted is advanced into' the work by a screw threaded rod engaging a correspondingly threaded sleeve on the carriage, being manually rotatable for adjusting the grinder wheel in relation to the work and axially movable by the automatic feed. For effecting the axial movement one end of the rod is coupled by a connecting rod to an eccentric on a transversely extending rotatable shaft, which shaft is rotated by a rack engaging a gear wheel thereon and itself intermittently actuated by metered hydraulic fluid. In case the work to be ground is a gear wheel, it is mounted on an arbor intermittently rotated by an indexing mechanism and movable axially relative to the grinder Wheel by a reciprocating carriage. It will be understood that the cross sectional contour of the grinder wheel is fashioned by a trimmer mechanism also mounted on the machine and occasionally operated to restore the contour which has been distorted by wear.

However, the accuracy of the gear ground on this automatic machine may not be as high as with grinding machines manually controlled, and gears generally are manually finished to obtain higher precision.

It ,is' the object of the invention to obtain a construction of grinding machine which is fully automatic and will produce as high or a higher degree of accuracy than possible by manual control.

To this end the invention consists in means operable after termination of the rough grinding of the work to approximate form and size, for taking one or more additional grinding cuts by the redressed grinder wheel, each of which cuts is of slight depth causing correspondingly slight wear of the grinder wheel to alter its contour or size. Thus, with a gear wheel all of the ground teeth thereof ,will be closely the same in contour and in radius from the axis of rotation. r

The invention further consists in the provision of a stop for limiting the feeding movement, which stop is minutely adjustable from a position for terminating the rough grinding to a position permitting a finishing cut.

The invention further consists in providing a second stop insertable to arrest movement of the feed member in a position intermediate the two positions effected by said first mentioned stop and used for a semi-finish grinding operation.

In the accompanying drawings:

Fig. 1 is a vertical longitudinal section through a portion of the grinder machine frame containing the automatic feed mechanism.

Fig-"218' a horizontal section on line-Z-Z, Fig. 1.

2,924,915 I Patented Feb. 16, 1960 Fig. 3 is a cross section on line 3-3, Fig. 4. Fig. 4 is a section on line 44, Fig. 3. Fig. 5 is a section-on line 5-5, Fig. 2. Fig. 6 is a section on line 6-6, Fig; 5.

As the general construction of the grinding machinemay be substantially the same as that in the patent above referred to, I shall omit illustration and description of the same and shall confine this case to the construction of the automatic feeding mechanism and controlling means therefor. It will be understood that this mechanism is mounted upon a portion of the frame of the grinding machine on which the carriage for the form grinder wheel is also mounted to be actuated thereby.

- of the rack bar but this does not insure that allof the contour and will also slightly diminish its size.

As shown in Figs. 1 and 4, A is a frame portion or head having a shaft B journaled therein to extend across a chamber A within said frame. On the shaft centrally within said chamber is an eccentric portion B. C is a connecting rod mounted on this eccentric portion by roller bearings C and at its lower end pivotally connected by a cross pin C with a member D slidable in a direction transverse to the axis of said shaft in a bearing A of the frame. The member D is hollow and has extending therein the end portion of a rod E which: is connected by end thrust roller bearings D with said member D to be coupled thereto for axial movement While free for relative rotation. The rod E is screw threaded and is coupled to the carriage for the grinder wheel (not shown) by a threaded sleeve or nut so that said carriage may be actuated either by the rotation of the rod or by its axial movement. These parts form no part of my invention and are the same as shown in the patent above referred to in which the screw threaded rod is rotated manually for adjustment of the grinder wheel in relation to the work and is automatically fed into the Work by the axial movement of the rod. A further feature of construction which is in common withthat of the patent above referred to is that the shaft B is rotated by a pinion B thereon which is in mesh with a rack F extending transversely to the axis of the shaft and slidable in bearings in the frame. The rack is hydraulically actuated and to this end has pistons F and F at its opposite ends engaging cylinders G and G? within the frame member A. Metered fluid under pressure is intermittently introduced into one of said cylinders'and fluid in the other cylinder is expelled therefrom, thereby producing a. step by step movement of the rack and corresponding rotation of the shaft B and its eccentric B, as is the case with the constructionof the patent above referred to.

While the construction as thus far describedcan be used for the automatic grinding of the work, such as the teeth of a gear wheel, the accuracy of the ground product is not as high as might be made by a form grinding machine controlled by a skilled operator. This is for the reason that there is always wear of thegrinder wheel during its grinding operation which may alter its formed Consequently if the teeth of a gear wheel are successively ground by a form grinder wheel, after the trimming of the same, they will not all be exactly alike as to contour and radial dimension from the axis of rotation. The amount of wear and change in contour of the grinder wheel is proportional to the depth of cut in the work so that to secure great accuracy the finishing grinding cut must be of slight depth. A skilled operator can accomplish this but with automatic feeding mechanism as thus far used it is diflicult to obtain. Thus, in the patent above referred to, each grinding cut is determined in depth by the quantity of hydraulic fluid metered to the cylinder, which is the same in successive cuts. The final cut or grinding pass is limited by a 'stop contacted by the end parts ground, such as the successive teeth of the gear, will be the same. 7

As above stated, my invention consists in the means for taking one or more final cuts in which the depth of penetration of the grinder wheel into the work is minute and of the order 'of ten thousandths of an inch.- Such limitation could not be produced by metering f the actuating hydraulic fluid. It'can however be obtained by a minute adjustment of the stop which limits movement of the rack bar and which I accomplish as follows:

At the left end of the frame A, as shown in Fig. 2, there is a housing A which is bolted or otherwise secured tosaid frame. In the wall of this housing adjacent to the frame is a hearing A for a cylindrical stop member H axially aligned with the cylinder G. The end of the member H within the housing A has an enlarged bifurcated head H with a roller H between the furcations thereof and mounted on a pin H Extending across the housing A in the plane of but transverse to the axis of the stop H is a guideway I on which is slidably mounted a member J. Attached to the member I is a cam J, the inclined face of which contacts the roller H The member I also has an arm I extending downward therefrom and attached to a rod K of a piston K engaging a cylinder K formed in the housing A The rod K is slidable through an inner head K of said cylinder which also has an outer head K Slidable within the head K? is a stop rod K which projects into the cylinder and may be adjusted into various positions therein to limit the.

stroke of the piston. A portion of the rod K is externally threaded and engages a nut member K which is swiveled in the head K so that by rotation of said nut in one direction or the other, the rod K will, be

moved inward or outward. The outer portion of the rod,

has calibrated markings K thereon indicating the amount of adjustment of the stop member H. Hydraulic connections K and K to opposite ends of the cylinder K will alternatively admit fluid to move the piston K from one end to the other of its freestroke. Thus, when thestop rod K is completely withdrawn from the cylinder K the piston will be moved the full length of the cylinder and through the rod K and arm J will move the cam J its full length. This through the roller H will move the stop member H between two positions separated from each other by the throw of the cam. If, however, the stop rod K is adjusted inward the spacing between the two positions of the stop H may be reduced to any amount desired. Normally the piston K will bein contact with the stop rod K of the left end of the cylinder K which will set the stop H to arrest movement of the rack bar F at the completion of the rough grinding operation. The stop H may then be adjusted as far as permitted by the position of the head K and after retrimming of the grinder wheel a finishing cut may be taken of the desired depth.

To obtain high accuracy in the ground product it may be desirable to take more than one cut around the vgear and to retrim the grinder wheel before each cut. This may be accomplished by the use of a second stop which limits the movement of the rack bar to a point between the two positions of arrest by the stop H. This second stop L is arranged in a housing M at the right end of the frame A, as shown in Fig. 2. A rod N connected to the rack bar extends outward therefrom within the housing M and the stop L in its normal position is out of the path of said rod but may be moved into registration therewith when required. As specifically shown the stop member L is pivotally attached to the housing M at L to swing on its pivot into or out of registration with said rod N. V The member L has in its free end portion an adjustable pin L which by the swinging of said arm may be registered in alignment with the rod N. The adjustment is by a screw threaded engagement between the pin and the member L, which after adjustment may be locked by a set screw L M is a downward extension at the outer end of the housing M which contains a solenoid 0 having a core member 0 movable upward when the solenoid is energized. The upper end of the core member contacts with an arcuate head L on the member L so that when energized the solenoid will move said member L into a position for registering the pin L with the rod N. Thus, in its normal position the stop member L does not interfere with the free movement of the rack bar and rod N to the right, as shown in Figs. 1 and 2. When, however,- it is desiredto use this stop the solenoid is energized and the pin L will be placed in the path of the rod N. Thus, when it is desired to take a semi-finishing cut prior to the final finishing cut, the stop rod K is first adjusted to space the two stop positions of the stop member H a distance from each other, which is the sum of the depth of the semi-finishing cut and the final finishing cut. The piston K is then moved to the left, Fig. 5 into contact with said head K after which the solenoid O is energized to register the pin L with the rod N. This pin may then be adjusted in the member L towards the rod N until spaced from the latter by an amount equal to the depth of thefinal finishing cut. The piston K is then moved to the right It is obvious that by the construction as above de-.

scribed that the semi-finishing and the final finishing cuts of the grinder wheel may be respectively of predetermined depths, Also these depths may be exact to the order of ten thousandths of an inch. Any inaccuracy in the rough ground work, either as to contour or to radial dimension withrespect to a common axis, maybe automatically corrected to as high or higher degree of accuracy as is possible by the manual control of a skilled workman.

What I claim as my invention is: I

1. In a grinding machine, mechanism for feeding a grinding wheel into a workpiece, a stop for arresting movement of said mechanism, a cam having a substantially planar cam surface engageable with said stop and movable transversely with respect thereto for minutely adjusting'the position ofsaid stop with a high degree of accuracy, and means for lineally moving said cam.

2. The construction as in claim 1 in which said means includes a hydraulic cylinder and piston motor having its movable member rigidly connected to said cam and positioning the same lineally at opposite ends of its stroke.

3. In a grinding machine, mechanism for feeding a grinding wheel into ,a workpiece, a 'stop for arresting movement of said mechanism, means including a cam having a substantially planar cam surface for minutely adjusting said stop between two positions with a high degree of accuracy, and a second stop for said feeding mechanism normally removed from obstructingthe same but movable into an arresting position for saidmechanism which is intermediate saidtwo positionsof arrest of said first-mentioned stop.

4. The construction as in claim 3 in which said feeding mechanism includes a longitudinally movable memher, said first-mentioned stop being in the path of one end of said member, and said second stop in its stopping position being in the path of the other end of said member.

5. The construction as in claim 4 in which said second stop is formed by an arm pivotally mounted to swing between obstructing and non-obstructing positions, and motor means for moving said arm from one of said positions to the other.

6. The construction as in claim 5 in which saidarm is in an unobstructing position when said motor means is deenergized and is moved into and held in obstructing position when said motor means is energized and in which the stopping surface of said arm is formed by a member carried by said arm and adjustable into difierent stopping positions.

7. In a grinding machine, mechanism for feeding a grinding wheel into a workpiece, a stop for arresting movement of said mechanism, means for minutely adjusting said stop between two arresting positions with a high degree of accuracy, and a second stop for said feeding mechanism normally removed from obstructing the same but movable into an arresting position for said mechanism which is intermediate said two arresting positions of said first mentioned stop. I

8. In a grinding machine, mechanism including a longitudinally movable member for feeding a grinding wheel into a workpiece, a stop for arresting movement of said mechanism, a cam having a substantially planar cam surface engageable with said stop and movable transversely with respect thereto for minutely adjusting the position of said stop between two positions with a high degree of accuracy, means for lineally moving said cam, including a hydraulic cylinder and piston motor having its movable member rigidly connected to said cam and positioning the same lineally at opposite ends of its stroke, a second stop for said feeding' mechanism normally removed from obstructing the same but movable into an arresting position for said mechanism which is intermediate said two positions of arrest of said first mentioned stop, and a pivotal mounting for said second stop whereby said second stop is adapted to swing between obstructing and non-obstructing positions, said second stop including motor means which when energized moves the second stop into obstructing position and when deenergized moves said second stop into non-obstructing position, said first mentioned stop being positioned in the path of one end of said longitudinally movable feed member, and said second stop in its obstructing position being in the path of the other end of said member.

9. In a grinding machine, mechanism for feeding a grinding wheel into a workpiece, a stop for arresting movement of said mechanism adjustable between two limiting positions and a second stop for said feeding mechanism movable into and out of an arresting position for said mechanism which is intermediate said two limit-' References Cited in the file of this patent UNITED STATES PATENTS 1,961,849 Fraser June 5, 1934 2,335,356 Price et a1 Nov. 30, 1943 2,792,673 Dammert May 21, 1957

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