US1873751A - Grinding machine - Google Patents

Description

Aug. 23, 1932. w. F. FRASER GRINDING MACHINE Filed July 25. 1927 3 Sheets-Sheet l allzl" IIIIIIIIIIIIIIIIIIIII I IIIIIIIIIIIIIIIIIIIIIII llIf/lV/ll a l:

'INVENTOR.

ATTORNEY.

Aug. 23, 1932. w. .F. FRASER GRINDING MACHINE Filed July 25, 1927 Fig.3. 0

3 Sheets-Sheet 2 Aug. 23, 1932. w E ER 1,873,751

- GRINDING MACHINE Filed July 25. 1927 s She ets-Sheet 5 Fig.4.

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Patented Aug. 23, 1932 stares PATENT ersice .WAEEEN F. FRASER, F WESTBOBQ, MASSACHUSETTS I GRINDING MACHINE V Application filed July 25, 1927. Serial No. 208,185.

' This invention relates to grinding ma- Themachine shown comprises a grinding chines and is especially concerned with grindwheel 2 and a work support 8 which isshown ing machines of the automatic type. somewhat diagrammatically in Fig. 4. This I It is the general object of the invention to machine is of the so-called cylindrical type 'fiimprove machines of this character with a and it is designed especially for grinding 55 view to producing more accurate and nut work having cylindrical or tapered external form results, and facilitating the making of surfaces such as pistons, shafts, shackle bolts, exact and rapid adjustments. g and the like. A work support of any suitable The invention will be herein disclosed as construction may be used in it, the support embodied in a machine of the type in which shown at 3 being designed to revolve an arti- 60 the wheel head and the work support are cle of work W around a stationary axis while mounted to produce relative approaching the grinding wheel 2 operates on it, suitable and receding movements of the work and mechanism being provided, if desired, to progrinding wheel, In such machines the apduce a relative traversingmotion of the preaching movement must be controlled very Wheel and work. 65

exactly in order to produce accurate results. The work support is mounted on upright T have found thatin machines of this, type extensions of the machine frame or base 4, the presence of oil films between the parts while the wheel 2 is mounted in a wheel head which limit the approaching movement is deor wheel support 5 which can be moved tocidedly detrimental to the high degree of acward or from the work. For this purpose 7O "curacy required in many classes of work. the support 5 is mounted on a bed 6which is Accordingly, it is an important object of this provided with a V-shaped guideway 7 and a invention to devise a construction in'which flat guideway 8, ,(see Figs. 3 and 5) the sup- 7 errors arising from this cause will be .elimport 5 having correspondingly shaped parts inated. to fit these guideways- This construction 75 The'nature of the invention will be readily permits a sliding movement of the whole und rstood from the following description wheel head or wheel support 5 toward or when read in connection with theaccompanyfrom the work W. V ing drawings, and the novel features will be The approaching movement of the wheel .30 particularly pointed out in the appended toward the work is produced by a spring 10, S0

' claims. Fig. 3, which is held in a casing 12 and which In the drawings, serves to force a plunger 13 outwardly,this Figure 1 is a plan view showing those plunger carrying a threaded stud or bolt 1 v parts of a grinding machine with which the which is adjustable in the plunger 13. The present invention is more especially constud or bolt 1 L acts on one end of a lever'15, 85 cerned the opposite end of this lever bearing against Fig. 2 is a perspective View showing a dea bar 16, Fig. 4, whichis rigidly mounted in tail of construction; j the wheel support 5 but is adjustable rela- Fig. '3 is a plan view of a portion of the tively thereto; So far as the operatlon of the machine frame andbed, the wheel headbeing spring 10 on the wheel support is concerned, 90

removed; 1 I the bar 16 may be considered to be an inte- Fig. 4is avertical, cross-sectional view ap gral part of the support 5. It Wlll be ev1- proximately on the line le-4, Fig.1; 1 dent from an inspection of Figs. 3 and 4 that T Fig. 5 is a cross-sectional view through the the spring 10 tends constantly to force the wheel head and a part of the supporting bed wheel 2 toward the work W. a r '95 therefor, the section being taken approxi The receding movement of the wheel relamately on the. line 5-5,. Fig. 1; and tively to the work is produced by a power Fig. 6 is a front View, partly in vertical driven mechanism which comprises a cam 17, cross-section, showing certain details of the Fig. 4, secured fastona driven shaft 1 8 and wheel head adjusting mechanism. arranged toosclllate a lever 20 which 1s fulcrumed on the machine frame at 21. An inclined guideway is provided on the upper side of this lever in which a wedge 22 is mounted, this wedge having a rod 23 connected to it which extends through an upright projection 24 on the rearward end of the lever. Nuts 2525, Fig. 4, threaded on the righthand end portion of the rod 23 serve to adjust this rod longitudinally, and this adjustment, in turn, adjusts the wedge 22 in its guideway. Bearing on the wedge 22 is an upright pin or rod 26, and one arm 27 of a bell crank lever bears on the upper end of t iis pin, while its other arm 28 engages a vertical face 30 formed on the bar 16. 2728 is supported on a pivot 31 which is mounted in cars 32-32, 2, of a bracket 33 which is set into a socket formed in the machine bed 6, the bracket being bolted securely to the bed so that it is to all intents and purposes, so far as-operation is concerned, an integral part of the bed.

It will be observed that when the machine is in operation the spring 10 will tend to hold the wheel 2 in contact with the work l/V, but that when the high part of the cam 17 operates to raise the lever 20, this'movement will be transmitted through the pin 26 and bell crank lever 2728 to the bar 16 which, being rigid with the wheel support 5, will give the wheel a receding or withdrawing movement away from the work. In a completely automatic machine the work is changed during this receding movement and a new article of work is presented to the wheel before the cam 17 again permits the lowering of the lever 20 and allows the spring 10 to move the wheel 2 again into contact with the work. The shape of this cam is such that after the wheel has engaged the work the cam still controls the rate of approach or feed of the wheel.

As above indicated, an important feature of this invention resides in the mechanism which limits the work approaching movement of the wheel 2. Referring to Figs. 2, 3 and 4 it will be seen that a bar 34 is secured in the recess 35 in the bracket 33, and that when the lowering movement of the lever 20 occurs, the work approaching movement of the wheel will be limited by the engagement of portions of the upright face 30 on the bar 16 with faces 39 of this fixed bar 34; In other words, this bar 34 acts as a stop, since it is 'xounted in a fixed position with reference to the machine frame. The time at which the approaching movement of the wheel head or work support 5'is stopped in the rotation of the cam 17 may be varied by adjusting the wedge 22 in the manner above described. That is, the bar 16 will strike the stop 34 and thus limit'the approaching movement of the wheel head at some time during the stroke which is imparted to the lever 20 by the cam 17, and the point in this stroke at which such The bell crank lever stopping of the movement of the wheel head occurs may be determined by adjusting the wedge 22. The portion of the stroke of said lever 20 which occurs after the wheel head is stopped results simply in a dwell or pause in the movement of the wheel head. It will be noted that the right-hand face, Fig. 4,.of the lever arm 28 moves into and out of contact with the upright face 30 on the bar 16, and that the upright face 30 also moves into and out of contact with the faces 39 on the bar 34. The pivot or fulcrum 31 for the lever 27-28 is positioned in a pocket formed in the base 6 which is adapted to hold a quantity of oil so that the pivot may be well lubricated, but the cooperating faces of the stop 34 and bar 16 are all located a substantial distance above this pocket so that they are kept substantially free of oil. They are also protect ed from dustby the fact that they are located under the wheel head 5 in a substantially closed chamber. This arrangement thus eliminates inaccuracies in the work which otherwise would be caused by the presence of oil or dust films on the surfaces of the parts which limit the work approaching movement.

In order to adjust the wheel angularly with reference to the work, the bed 6 on which the wheel support 5 slides is mounted on a horizontal planed surface on the frame or base 4 and is pivoted on a bushing 36 through which the pin 26 projects. An extension 37 of this bed projects forward through the front of the frame 4 and overlies a bracket 38 rigid with the frame. Adjusting screws 40-40 are threaded through upright lugs formed on this bracket and bear against the opposite sides of the extension 37 where they can be conveniently manipulated to adjust the angular relationship of the grinding wheel and the work. A bolt 41 projects through both the extension 37 and the bracket 38 and serves to lock the bed in its adjusted position.

For the purpose of adjusting the grinding Wheel to work of different diameters, the bar 16 is mounted to slide in the wheel support 5 but is prevented from rotating by the key 42, Fig. 4, and the forward or left-hand end of the bar is screw threaded, as shown at 43. An internally threaded sleeve 44 is mounted on the threaded portion 43 of the bar and is secured by means of a key and a nut 47 to a hand wheel 45 through which the sleeve maybe rotated to adjust the bar 16, and consequently the wheel 2, toward or from the work. The sleeve is held by parts 46 and 47-against axial movement relatively to the bracket 56 which is secured to the support 5 by means of the part 59. This permits a fine adjustment of the bar 16 with relation to the wheel head, and the periphery of the hand wheel 45 preferably is graduated, as shown in Fig. l, to cooperate with a stationary pointer 48, Figs. 1 and 4, in making these adjustments.

For extremely fine adjustments a micrometer screw mechanism also is provided. That is, a worm wheel 50 is bolted securely to the hand wheel 45 which is keyed to the sleeve 46 so that it must rotate with it, and a micrometer screw 51, Fig. 6, is arranged to mesh with and drive the worm wheel 50. This screw is mounted on the lower end of a shaft 52 which is rotatably supported in a bracket 53, the upper end of the shaft being provided with a graduated finger wheel 54. The bracket 53 is pivoted at 55, Fig. 6, on a stationary casing 56 in which the screw threaded sleeve 44 is mounted, and this pivotal support permits the movement of the micrometer screw into or out of mesh with the worm wheel 50. Normally the screw is held out of contact with the worm wheel by a spring 57, Figs. 1 and 6, which encircles a rod 58 and bears against a portion of the bracket 53. It may be moved into mesh with the worm wheel, however, by a cam 6O having a handle 61, the cam being mounted to rotate on the rod 58 and cooperating with a stationary cam member 62, secured on. said rod, to force the lower end of the bracket inwardly far enough to carry the screw 51 into mesh with the worm wheel 50 and hold it there. A pin 63, Fig. 6, projecting from the cam 60 and, working in a slot formed in the bracket 53, limits the operative move ment of the cam. Fig. 6 shows the micrometer adjusting mechanism in its operative position. When the handle 61 is moved backwardly the spring 57 immediately throws the screw 51' out of mesh with the worm wheel 50.

The screw threaded mechanism which cooperates with the left-hand end, Fig. 4, of the bar 16 serves to make adjustments of the wheel head or wheel support 5 relatively to the bar 16, the bar being held between the levers 15 and 28, so that the grinding wheel is adjusted relatively to the work, and these adjustments can be made very minute, if desired, through the use of the micrometer mechanism. These adjustments also determine the relationship of the grinding wheel to the work.

The invention thus provides a grinding machine in which extreme accuracy can be obtained and in which this accuracy is not likely to be disturbed by-the presence of oil films, dust or the like.

While a preferred embodiment of the invention has been herein shown and described, it will be understood that the invention may be embodied in other forms without departing from the spirit or scope thereof.

Having thus described my invention, what I desire to claim as new is:

I claim:

1. In an automatic grinding machine, the combination of a wheel support, a work support, a machine bed having guideways upon .1 which one of said supports is mounted for sliding movement to produce a relative approaching or" receding movement of the Work and grinding wheel, a bar adjustable in said slidable support, screw threaded means for making fine adjustments of said bar relatively to said slidable support, power driven mechanism operable through said bar to produce said? receding movement; a spring for producing said approaching movement, said mechanism including a power, driven cam and a lever mechanism through whlch motion 1s transmitted from sa1d cam to said bar,

7 one of the levers of said mechanism including an arm arranged to act on the bar mone direction; and a stop for engaging said bar and limiting its movement in; the opposite direction.

2. In an automatic grinding machine, the

combination of-a grinding wheel support, a

work support, a, machine bed having guideways, upon which one, of said supports is mounted for sliding movement to permit relative approaching and receding movements of the work and grinding wheel, a machine frame supporting said bed, a hollow pivot connecting said bed and frame for angular adjustment of the bed on the frame, abar adjustable in said slidable support, power driven mechanism operable through said bar to produce said receding movement, and yieldable means for producing said ap preaching movement, said mechanism comprising a cam and connections between said cam-and said bar, lncludlng a member sl dably mounted in said hollow pivot, for moving's'a'id bar in one direction.

3. In an automatic grinding machine, the comb nation of a grinding wheel support, a work support, a machine bed having guldeways upon which one of said supports is mounted for horizontal sliding movement to produce relative approaching and receding movements of the work and grinding wheel,

a horizontal bar adjustable in said slidable support, screw threaded means for adjusting said bar relatively to said slidable support, said bar having an upright shoulder, a bell crank lever mounted on said bed and having an arm to engage said shoulder and a second arm extending at an angle thereto, a power driven cam, a lever arranged to be actuated by said cam, and connections between the latter lever and the second arm of said bell crank lever for operating said bell crank lever to cause it to engage said bar and thereby produce said receding movement of said slidable support.

4. In an automatic grinding machine, the

combination of a grinding wheel support, a

work support, a machine bed having guideways upon which one of said supports is mounted for horizontal sliding movement to produce relative approaching and receding movements of the Work and grinding Wheel,

a horizontal bar adjustable in said slidable support, screw threaded means for adjusting said bar relatively to said slidable support,

said bar having an upright shoulder a bell crank lever mounted on said bed and having an arm to engage said shoulder and a second arm extending at an angle thereto, a power driven cam, a lever arranged to be actuated by said cam, connections between the latter lever and the second arm of said bell crank lever for operating said bell crank lever to cause it to engage said bar and thereby produce said receding movement of said slidable support a spring for producing said relative approaching movement, and a stop rigid With the machine frame and arrangedto engage said bar to limit said relative approaching movement.

5. In an automatic grinding machine, the combination of a grinding Wheel support; a Work support; a machine bed having guide- Ways upon Which one of said supports is mounted for sliding movement to produce relative approaching and receding movements of the Work and grinding Wheel; arod adjustable in said slidable support; screw threaded means for adjusting said rod relatively to said support; power driven mechanism operable through said rod to control said approaching movement; and a stop rigid Withthe machine frame for engaging said rod and limiting said approaching movement, said mechanism comprising a power driven cam, a lever operated thereby, means for transmitting the motion of said lever to said rod, and means adjustable to vary the range of movement imparted to sald slldable support by said cam.

WARREN F. FRASER.

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