US2778165A - Centerless grinding machine - Google Patents

Description

Jan. 22, 195? w. STAHLECKER ET AL 2,778,165

CENTERLESS GRINDING MACHINE Filed Nov. 30, 1953 4 Sheets-Sheet l 'LJILHELM STAHLECKER AND HANS RH-L 1957 w. STAHLECKER ET AL 65 CENTERLESS GRINDING MACHINE Filed Nov. 30, 1953 4 Sheets-Sheet 2 L/ILHELM STAHLaKe-R AND HANS @RLL 1957 w. STAHLECKER ETAL 2,778,165

CENTERLESS GRINDING MACHINE Filed Nov. 30, 1953 4 Sheets-Sheet 3 INVENTORI Wdheflm sfqhleckek 1957 w. STAHLECKER ETAL 2,778,165

CENTERLESS GRINDING MACHINE Filed Nov. 30, 1953 4 Sheets-Sheet 4 and By.- HMII 6m! 2,7 7 8,165 CENTERLESS GRINDING MACHINE Wilhelm Stahlecker, 'Iuhingen, and Hans Grill, Sussen, Germany Application November 30, 1953, Serial No. 395,241 Claims priority, application Germany December 6, 1952 9 Claims. '(Cl. 51-103) purposes, but also of objects of conical, convex, and similar shapes.

More specifically, it is an object of the invention to devise a machine for grinding roller-shaped bodies or similar objects to various shapes, wherein such objects are rotatably mounted by their axles, studs or hearing pins in a stirrup or bracket which, in turn, is pivotable in all directions about a certain point distant from the axis of the objects so as to automatically with theiraxes parallel driving. means thereof.

It is a further object of the invention to provide a machine of the type described with additionalmeans for positively moving the objects to beground in certain directions about the pivotal point of their guiding bracket .so as to permit these objects to be ground either to "an accurate cylindrical shape, a conical shape, or a convex shape.

Conical surfaces may possibly be ground. on substantially cylindrical objects by adjusting the rotary axis of the driving roller relative to the axis of the grinding wheel so as to extend at an angle thereto which corresponds to the desired angle of the conical surface to be ground. However, such driving mechanism "has the disadvantage of being rather complicated as well as expensive in manufacture since it would require that the entire heavy driving roller be pivoted from its normal position to the axis of the [parallel with the axis of the grinding wheel to such inclined position, preferably even without interruption of permit the objects to adjust themselves.

its driving action while such adjustment is being carried out.

It has now been found according to the invention that, even though the driving roller extends parallel with the axis of the grinding wheel, conical surfaces may also be ground on previously cylindrical objects by guiding the bracket, on which the object is mounted and which is pivotable in all directions at a point remote from such object, so as to allow the object, aside from its rotation about its own axis, movements. 7

Accordingly, it is afeature of the invention to provide means for guiding the object to be ground so as to be only certain independent pivotal "independently movable, aside from the rotation about its own axis, only in a circular direction about the pivotal point of the bracket carrying the same within a plane passing through such pivotal point and extending at a right angle to the axis of said body, as well as about an axis extending within such planeand connecting the axis of the object to be ground with the pivoting point of "the bracket.

the body to be and for this purpose it may be provided with means for "shifting it laterally,

the direction shown by the shaped-body '2 which is to be ground in the the guiding bracket 5, whereas the two ends of carrying the half-she'lls -d, as well as the opposite end 'of I 2,778,165 Federated Jan. 22, 1957 According to another feature of the invention, the

bracket may, aside from such independent movementof ground, also be given a positive movement,

so as to enable the grinding not only of slightly conical surfaces, but also of convex surfaces without requiring any adjustment of the axis of the driving roller to be'made. l

*Further'objects, features, and advantages of the present invention will appear from the following detailed description of several embodiments thereof and the appended drawings, in which I Fig. 1 is a side view of a grinding machine according to the invention, which is provided with a stirrup or bracket for supporting and guiding a roller-shaped body, and which includes a new mechanism for shifting such body from its normal central position toward one side, so

as'to permit grinding of .a conical surface thereon; #Fig. 2 is :a top view'of the grinding machine shown in Fig. l;

Fig. 3 is a view similar to Fig. 2, but only showing a *Fig. fiis a view similar to "Fig. 3, in which the body to be ground is-disp'osed at an angle relative to the axis of the-driving roller for grinding a conical surface on body; 1 Fig. 5 is a side view of a -to another 'embodimentof the invention, in which two rollers may be ground "simultaneously, and wherein the bracket for supporting and guiding said bodies may be shifted laterallyyby means of an eccentric lever or pin;

,7 Fig. 6 is a front view of the roller-shaped bodies to be "ground by a machine as shown in Fig. 5, and as seen in A arrow VI of Fig. 5;

Fig. 7 is a top view of the grinding machine shown in Fig. 5

Pig. 6 is a side view of. a grinding machine similar to 5, but provided with a mechanism for that shown in Fig. ele'ctromagnetically arresting the lateral movement of the V guiding bracket; 1

Fig. 9 is aside view similar to Fig. 8 and showing a tracer for controlling-the electromagnet;

Fig. 1 0 is a top view of a grinding machine according to a further embodiment of the invention;

Fig. 11 is a partly sectional side view of another emgrinding machine according to the inven- Fig. 12 is a top view of the embodiment shown in As shown particularly in Figs. 1 and 2 of the drawings,

The rollermachine is rotatablysupported on an axle 6 by means of two sets of ball bearings 7. The two projecting end portions of the axle ;6 are halfway embraced from above by halfshells '8 which are secured to a stirrup or fork 9 at one zontal axis ona suitable machine frame.

-end'o f'a guiding bracket 5. The other end of the bracket 5 carries a ball ,4 which is supported in a ball cup 11 which is fixed to the frame of the machine. As shown especially in Fig. 1, the main portion of the fork 9 extends substantially in the same plane as the central portion of the fork 9 the bracket 5 carrying substantially at a part.

Thus, the guiding bracket 5 :tically as *wellas laterally,

the ball 4, are bent downwardly right angle relative to such central would be able to pivot verexcept for the provision ofia grinding machine according guiding element 12 which prevents the bracket from pivoting laterally in a direction parallel to the horizontal plane passing through the ball and socket joint 4, 11. The guiding element 12 is slidably adjustable on a rail 13 on the machine frame in a direction substantially parallel with the axis of the driving roller 1; and may be fixed thereto by means of a thumb screw or the like. To ensure adequate frictional engagement between the driving roller 1 and the body 2 necessary for driving the latter, a suitable weight is suspended on the central part of the bracket 5. As indicated in Figs. 5, 7, and 8, suitable means may be provided to adjust the position of the weight 15 in longitudinal direction of the bracket 5 so as to vary the pressure of the body 2 upon the driving roller 1.

in the position shown in Figs. 1 to 3, the guiding element 12 is secured at the central point of the rail 13, so that the body 2 to be ground in the machine will extend parallel with the driving roller 1 as well as with the rotary axis of the grinding wheel 3, the driving and supporting elements of which are not shown in the drawings. Thus, when the grinding wheel 3 is driven in contact and shifted in a direction parallel to the axis of the body 2, the latter will be ground to an accurate cylindrical shape.

In the position of the various elements shown in Fig. 4, the guiding element 12, together with the bracket 5, is shifted slightly laterally from its central position on the rail 13 so as to maintain the roller-shaped body 2 at a slight inclination relative to the grinding wheel 3. 'Thus, as shown in Fig. 4, the formerly cylindrical body 2 may be ground to a slightly conical shape, the angle and direction of such cone depending upon the amount or degree which the guiding element 12 is shifted laterally from its central position toward one end'or the other of the rail 13.

Figs. 5, 6, and 7 of the drawings illustrate a grinding machine according to the invention which permits two roller-shaped bodies 2 to be ground simultaneously. The two bodies are rotatably mounted on a common axle 6 and are depressed by the guiding bracket 19 by means of a half-shell 28 fitted from above upon the central part of the axle 6 intermediate the two ends thereof carrying the two bodies 2. The half-shell 28 is provided'with two upwardly extending arms 28' having vertical slots 32 therein. The guiding bracket 19 is operatively connected to shell 28 intermediate the said arms 28' by means of pins 29 fixed to bracket 19 and extending into the slots 32 so as to allow a certain movement of the member 28 relative to the bracket 19. The latter is further provided at its forward end with a small central knife edge 14 (Fig. 6) which transmits the pressure produced by the weight 15 upon the axle 6 and the roller-shaped body or bodies 2, and permits minor tilting or pivoting move ments of the axle 6 about the knife edge 14.

The rear end of the guiding bracket 19 is connected bymeans of a universal joint on a bar 20, which is secured to or forms a part of the machine frame, so as to permit both vertical as Well as lateral pivotal movements of the bracket 19. Such universal joint may, for example, consist of a central member 21 which is rotatably mounted on the bar 2% and pivotable about a vertical axis on two pins 18 within the bifurcated end of the bracket 19. Two rings 22 secured to the bar at opposite sides of the member 21 prevent the latter from sliding laterally there- The lateral pivotal movements of the guiding bracket 19 are positively controlled by an eccentric member 16 which is rotatably secured by means of a shaft 31 in a art t its upper end which engages in a slot 34 extending longitudinally of the bracket 19. The eccentric pin 30 may either be fixed to the member 16, or suitable meanes may be provided to adjust the amount of its eccentricity relative to the shaft 31. Thus, by rotation of the shaft 31 by suitable driving means which are not shown in the of the machine frame and has an eccentric pin 30 either manually,

. able tracer may be provided which may act upon,

, projection 38 fixed to drawings, the eccentric movement of the pin 30 in the slot 34 is transmitted to the bracket 19 to pivot the same laterally about its pivotal axis 18 to carry out a reciprocatory movement for rounding oil the bodies 2 toward their opposite outer edges. Thereafter, if desired, the position of the roller-shaped bodies 2 on the axle 6 may be reversed, so as to permit grinding of the two other ends and to obtain evenly convex outer surfaces thereon. Obviously, the means above described for reciprocating the guiding bracket may also be provided in the embodiment of the invention shown in Figs. 1 to 4, in which event a convex surface may be ground on the rollershaped body 2 in one continuous operation and without requiring any reversal of such body on the axle 6.

The machine shown in Figs. 5 to 7 may be used not only for grinding convex bodies, as above described, but also for producing cylindrical or conical rollers. For producing cylindrical rollers, the rotary movement of the shaft 31 is stopped and the eccentric pin 30 is turned so as to be in the central or neutral position, as shown in Fig. 7, whereupon the thumb screw 17 is tightened to lock the pin 30 in such neutral position. The same procedure is applied for producing slightly conical bodies, except for the fact that in such a case the required conical angle is adjusted by turning of the eccentric pin 30 toward one side or the other, and by then locking of it in such position by the thumb screw 17.

The grinding machine according to the embodiment of the invention shown in Fig. 8 corresponds in most details to that shown in Figs. 5 to 7, except for the fact that in place of the eccentric 30, 31 the guiding bracket 25 may be adjustably secured by means of an electromagnet 26 which, when energized, is adapted to hold a plate 27 with two upwardly extending arms 24 in a fixed position thereon. A transverse pin in the bracket 25 slidably engages in the slots 35 in the arms 24. As may be seen in Fig. 8, the slots 35 extend along the arc of a circle, the center of which coincides with the center of the bar 20 about which the bracket 25 is able to pivot in a vertical direction. Thus, when the current is connected to energize the magnet 26, the plate 27 is secured in a fixed position either centrally on the magnet 26 to produce cylindrical rollers or toward the front or rear, as viewed in Fig. 8, to produce slightly conical bodies, and it thereby prevents any lateral movement of the bracket 25 without, however, affecting its vertical movement or its slight tilting movement. Also, the machine illustrated in Fig. 8 may additionally be provided with an eccentric mechanism, similarly as shown in Figs. 5 and 7, for producing convex bodies, in which event the magnet 26 is disconnected to allow the plate 27 to slide loosely thereon.

The magnet 26 may be connected or disconnected semiautomatically, or fully automaticalsuch automatic control of the magnet 26, a suitor be acted upon by, the grinding wheel or cylinder 3, as shown in Fig; 9. Referring to Fig. 9, it will be seen that the lever 37 is turnable about the stationary pivot pin 39 and carries at its lower end a female electrical plug member adapted to cooperate with the male electrical plug member 36 fixed to a stationary part of the machine as indicated in Fig. 9. The spring 40 urges these plug members into operative engagement with each other, as shown in the solid line position of lever 37, so as to energize the electromagnet 26 and to maintain the plate 27 in a predetermined angular position. When the grinding operation has been completed, the grinding wheel 3 is moved in a known manner away from the workpiece 2 to the dotted line position shown at 3 in Fig. 9, and a a bearing for the grinding wheel engages the top end portion of lever 37 during movement of the grinding wheel to its inoperative position to turn the lever 37 in a counterclockwise direction about pin 39, as viewed in Fig. 9, so as to separate plug members 36 and 36' and thus open the circuit to the electromagnet to ly. For

the eccentric shaft 30 deenergize the latter. Thus, the electromagnet 26 is automatically energized when the grinding wheel is in its operative position engaging the workpiece and is autoinatica lly deenergized when the grinding wheel 3 is moved to rts inoperative position.

In place of the grinding or, In a tandem arrangement as shown in Figs. 5 to 8, a separate grinding wheel may be provided for each of the bodies to be ground, as shown in Fig. 10.

c The structure described above and shown in Figs. l-8 is capable of providing slightly conical or slightly spheriin Figs. 11 and 12. As is shown in Figs. 11 and 12, the bracket 19 and the driving roller 1 are turned simultaneously through the same For this purpose the driving roller 1 is turnably which is turnable about its stationary pivot pin 46 which is coaxial with the pivot'pi'ns 18. Turning movement of bracket 19 and tape 42, as well as the bearings 41 for the roller 1 therewith, is produced by which is common to elements 19 and 42. This shaft 30 extends freely through an elongated flap 43 formed in plate 42 as well as into the slot 34 of bracket 19, and as was described above, shaft 31 together with disc 16 may be turned to rotate the shaft about the axis of shaft 31 so as to reciprocate the shaft 6 and the workpiece 2 carried thereby about the common extending between pulleys respectively connected to the motor and driving roller. Motor 47 can be very small since only a small amount of energy is required to drive roller 1 and workpiece 2.

When the claims recite an axle for rotatably mounting the bodies to be ground on the machine, it is to be expressly understood that this term is to include an axle as well as bearing pins or studs which are either fixed to the respective body and projecting from at least one end thereof, or on which the respective body is rotatably mounted and secured from sliding in axial direction thereof.

While we have described our invention with reference to several preferred embodiments thereof, we wish it to be understood that our invention is in no way limited to the details of such embodiments but is capable of numerous modifications within the scope of the appended claims.

What we claim is:

1. Centerless grinding machine for grinding" a substantially cylindrical body having an axle protruding from said body comprising in combination a frame, a driving roller mounted substantially horizontally on said frame and adapted to drive said cylindrical body by frictional engagement therewith when said body is placed on top thereof, means for driving said roller, a grinding wheel, means for rotatably mounting and driving said grinding wheel, means for placing said grinding wheel in engagement with said body so as to grind the outer surface thereof, a bracket, means at one end of said bracket for pivotally mounting the same on said frame so as to be pivotable in various directions, at least one half-shell of a bearing secured to the other end of said bracket and adapted to partly embrace said axle from above, means acting upon said bracket for pressing said half-shell upon said axle to press said body upon said driving roller so as to be driven thereby, and means for restraining said bracketfrom moving in at least one direction about said pivotal mounting means so that the body to be ground, aside from rotating about its own axis, can move independently only in a circular direction about the pivoting point of said bracket within a plane passing through said pivoting point and extending at a right angle to the axis of said body, as well as about an axis lying within said plane and substantially connecting the axis of the body to be ground with said pivoting point.

'2. Centerless grinding machine as defined in claim 1, further comprising means for positively moving said bracket laterally about its pivoting point within a substantially horizontalplane, and means for arresting said lateral movement of said bracket in any position within said horizontal plane.

3. In a centerless grinding machine, in combination, a driving roller adapted torotate about a stationary axis coincident with its'own axis; a shaft located over and being substantially parallel to said roller for rotatably supporting a workpiece in engagement with said roller, whereby the workpiece may be rotated by said roller and ground by a grinding wheel engaging the workpiece; and means engaging said shaft for constraining the same to turn about a first turning axis parallel to said stationary axis and spaced from said roller and shaft and for turning said shaft about a second turning axis normal to said first turning axis and substantially parallel to an axis normal to and passing through the axes of said roller and shaft.

4. In a centerless grinding machine, in combination, a driving roller adapted to rotate about a stationary axis coincident with its own axis; a shaft located over said driving roller for rotatably supporting a workpiece in engagement with said roller, whereby the workpiece may be rotated by said roller and ground by a grinding wheel engaging the workpiece; and means engaging said shaft for-constraining the same to turn about a first turning axis parallel to said stationary axis and spaced from said roller and shaft, for turning said shaft about a second turning axis normal to said first turning axis and substantially parallel to an axis normal to and passing through the axes ofsaid roller and shaft, and for guiding said shaft for tilting movement about a third turning axis which is parallel to an axis normal to said first and second turning axes and passing through the intersection therebetween.

5. In a Centerless grinding machine, in combination, a driving-roller adaptedto rotate about a stationary axis coincident with its own axis; a shaft located over said driving roller for rotatably supporting a workpiece in engagement with saidgroller, whereby the workpiece may be rotated by said roller and ground by a grinding wheel engaging the workpiece; means engaging said shaft for constraining the same to turn about a first turning axis parallel to said stationary axis and spaced from said roller and shaft and for turning said shaft about a second turning axis normal to said first turning axis and substantially parallel to an axis normal to and passing through the axes of said roller andshaft; and means for releasably fixing said shaft in a predetermined angular position with respect to said second turning axis.

6. Centerless grinding machine for grinding a substantially cylindrical body having an axle protruding from said body comprising, in combination, a frame; a driving roller mounted substantially horizontally on said frame and adapted to drive the cylindrical body by frictional engagement therewith when the body is placed on top thereof; means for driving said roller; a grinding wheel; means for rotatably mounting and driving said grinding wheel; means for placing said grinding wheel in engagement with the body so as to grind the outer surface thereof; a bracket; means at one end of said bracket for pivotally mounting the same on said frame so as to be pivotable in various directions; at least one half-shell of a bearing secured to the other end of said bracket and partly embracing said axle from above; means acting upon said bracket for pressing said half-shell upon said axle to press the body upon said driving roller so as to be driven thereby; means for restraining said bracket for moving in at least one direction about said pivotable mounting means so that the body to be ground, aside from rotating about its own axis, can move independently only in a circular direction about the pivoting point of said bracket within a plane passing through said pivoting point and extending at a right angle to the axis of the body, as well as about an axis lying within said plane and substantially connecting the axis to be ground with said pivoting point; and eccentric means for positively moving said bracket laterally about its pivoting point within a substantially horizontal plane.

7. Ccnterless grinding machine for grinding a substantially cylindrical body having an axle protruding from said body comprising, in combination, a frame; a driving roller mounted substantially horizontally on said frame and adapted to drive the cylindrical body by frictional engagement therewith when the body is placed on 'top thereof; means for driving said roller; a grinding wheel; means for rotatably mounting and driving said grinding wheel; means for placing said grinding wheel in engagement with the body so as to grind the outer surface thereof; a bracket; means at one end of said bracket for pivotally mounting the same on said frame so as to be pivotable in various directions; at least one half-shell of a bearing secured to the other end of said bracket and partly embracing said axle from above; means acting upon said bracket for pressing said half-shell upon said axle to press the body upon said driving roller so as to be driven thereby; means for restraining said bracket for moving in at least one direction about said pivotable mounting means so that the body to be ground, aside from rotating about its own axis, can move independently only in a circular direction about the pivoting point of said bracket within a plane passing through said pivoting point and extending at a right angle to the axis of the body, as well as about an axis lying within said plane and substantially connecting the axis to be ground with said pivoting point; and eccentric means for reciprocating said bracket laterally about its pivoting point within a substantially horizontal plane.

8. Ccnterless grinding machine for grinding a substantially cylindrical body having an axle protruding from said body comprising, in combination, a frame; a driving roller mounted substantially horizontally on said frame and adapted to drive the cylindrical body by frictional engagement therewith when the body is placed on top thereof; means for driving said roller; a grinding wheel; means for rotatably mounting and driving said grinding wheel; means for placing said grinding wheel in engagement with the body so as to grind the outer surface thereof; a bracket; means at one end of said bracket for pivotally mounting the same on said frame so as to be pivotable in various directions; at least one half-shell of a bearing secured to the other end of said bracket and partly embracing said axle from above; means acting upon said bracket for pressing said half-shell upon said axle to press point and extending at a right angle to the axis the body upon said driving roller so as to be driven thereby; means for restraining said bracket for moving in at least one direction about said pivotable mounting means so that the body to be ground, aside from rotating about its own axis, can move independently only in a circular direction about the pivoting point of said bracket within a plane passing through said pivoting point and extending at a right angle to the axis of the body, as well as about an axis lying within said plane and substantially connecting the axis to be ground with said pivoting point; eccentric means for reciprocating said bracket laterally about its pivoting point within a substantially horizontal plane; and means for arresting said lateral movement of said bracket in any position within said horizontal plane.

9. Centerless grinding machine for grinding a substantially cylindrical body having an axle protruding from said body comprising, in combination, a frame; a driving roller mounted substantially horizontally on said frame and adapted to drive the cylindrical body by frictional engagement therewith when the body is placed on top thereof; means for driving said roller; a grinding wheel; means for rotatably mounting and driving said grinding wheel; means for placing said grinding wheel in engagement with the body so as to grind the outer surface thereof; a bracket; means at one end of said bracket for pivotally mounting the same on said frame so as to be pivotable in various directions; at least one half-shell of a bearing secured to the other end of said bracket and partly embracing said axle from above; means acting upon said bracket for pressing said half-shell upon said axle to press the body upon said driving roller so as to be driven thereby; means for restraining said bracket for moving in at least one direction about said pivotable mounting means so that the body to be ground, aside from rotating about its own axis, can move independently only in a circular direction about the pivoting point of said bracket within a plane passing through said pivoting of the body, as well as about an axis lying within said plane and substantially connecting the axis to be ground with said pivoting point; eccentric means for positively moving said bracket laterally about its pivoting point within a substantially horizontal plane; and electromagnetic means for arresting said lateral movement of said bracket in any position within said horizontal plane.

References Cited in the file of this patent UNITED STATES PATENTS 566,122 Ashton Aug. 18, 1896 1,779,618 Phelps Oct. 28, 1930 1,879,110 Cramer Sept. 27, 1932. 2,012,716 Colchensky Aug. 27, 1935 2,039,223 Hutchinson Apr. 28, 1936 2,045,894 Binns June 30, 1936 2,242,031 Hjarpe May 13, 1941 2,622,373 Stahlecker Dec. 23, 1952 FOREIGN PATENTS 838,572 Germany May 8, 1952

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