US2406134A - Tool grinding machine - Google Patents

Description

Aug. 20, 1946.

J. A. CAMERON 2,406,134

TOOL GRINDING MACHINE I I Filed July 5, 1943 2 Sheets-Sheet 1 INVENTOR. warp/1A 674M590 0, 1946. J. A. CAMERON 2,406,134

TOOL GRINDING MACHINE Filed July 5, 1943 2 Sheets-Sheet 2 16 INVENTOR was /r 4. 62/192790 Patented Aug. 20, 1946 UNI TED STATES PAT EN 1 r r 2,406,134 i "ibOL GafNnING MACHINE Joseph ameron, Los Angeles; Calif. Application Jilly 5, 1943; Sea No. 493,556 I V raisin. (01. 51-161) This invention has to do with grinding Inachines, and more particularly with grinding machines for grinding surfaces which depart from a circular cross section.

Grinding machines of various designs for grinding cylindrical surfaces arein common use, while other known grinding machines are designed to grind solids of specific generation such as the surfaces of gear teeth or cam shapes. Such machines, however, are limited to the configuration of, the surface which may be ground, or require major and time consuming changes to adapt them to the grinding of a difierent surface.

It is a general object of the present invention to provide a grinding machine which is capable of grinding not only cylindrical surfaces but to grind a wide variety of eccentric and irregular surfaces with a minimum of unproductiv time and effort in changing from one job to another.

It is another object of the invention to provide a grinding machine which is capable of grinding surfaces, the axes of which'are either parallel tool at an angle with the axis of the grinding wheel.

A further-object of my invention is to provide a grinding means which may be arranged either as an attachment or addition to a conventional grinding machine, or as an independent grinding machine.

A still further object of my invention is to provide a grinding machine which is capable of both internal and external grinding operations.

A still further object of my invention is to provide a grinding machine which is simple of construction, economical of manufacture, durable and eflicient in its action.

The grinding machine of the present invention employs a control cam to effect a movement of the rotating workpiece toward and from the grinding wheel during the grinding operation. By this means, contours of various kinds may easily be provided merely by choice or design of proper cams. Preferably, and in accordance with a present illustrative embodiment of the invention; the control cam is secured to amtatable headstock spindle and the workpiece to be ground is secured in a suitable chuck of conventional design such as a three or four jaw chuck or collet chuck of the type used in engine lathes. The control cam and workpiece are then rotated at a suitable speed and the workpiece is caused to move laterally to and from the grinding wheel during the course of each revolution in accordanc with the configuration of the control cam.

- 1 2 l The various features and accomplishments as:

my invention, as well as other f'objects and rea tur'es'wli'ich are preliminarily mentioned, will be set forth in the following detailed description at a present preferred illustrative embodiment of, the invention, reference for this purpose being had to the accompanying drawings, in which: V r Fig. 1 is a fragmentary side elevational View 'of my grinding machine showing the workpiece being hel'd b'yaj'aw chuck; Fig. 2 is a transverse sectional Viewthrof taken through 2-2 of Fig. l;

Fig. 3 is a fragmentarysectional View taken along the line 33 of Fig. 1; I H e v Fig. 4 is an 'enlargedsectionalview through the workpiece and control cam receiving enjdgf. the headstock spindle, showing a collet chuck positioned thereon;

in plan Fig. 5 is a diagram'matical view showingthe angular relationship of workpiece cam andigrind wheel for grinding the clearance angle required for a tap, end mill, router or the like; L

Fig. 6 is a view similar to Fig. 5, but showing a different position of the parts; and n e I Fig. 7 is another diagrammatic view "showing the angular relationship of the control cam cam follower, workpiece and grind wheel for grindmg a square opening in the workpiece.

Th grinding machine is mounted n a 'brkbed'or bed frame I whic may be of conventional design and may be supported and arranged by means not shown, but which may beof any conventional type, for movement both longitudinally and transversely or merely longitudinally with respect to a grinding wheel G, and also for pivotal movement on a vertical axis with respect to thegri'nding wheel. The grinding wheel is supported and driven in a suitable conventional manner, not shown. be so mounted as to move lengthwise of the bed frame or transversely thereto or inboth direc"-' tions much in the manner of the cross feed of a lathe." Since supporting arrangements fenneindicated relative movements of" the 'work bed I and grinding wheel G are well known in the art, and may be of a conventional'n'ature no illustra tion thereof is deemed necessary'in the present drawings; a Me A headstock; base structure 2 is mounted on the work bed I. This base structure may be a member of inverted channel cross section and is secured near one end to the midportion of the work bed I by a pivot pin 3. The pivot pin may be in the form of a bolt adapted, when loosened,- to permit angular adjustment of the base structure The grinding wheel nary l the control cam I6.

jwith respect to the bed frame I about a vertiical axis; and, when tightened, to secure the base structure 2 in its adjusted position. While a bolt is-shown for simplicity,it is of course obvious that more elaborate securing and adjusting jmeans may be provided to facilitate accurate angular adjustment of the base structure 2.

The pivoted end of th base structure may be "rounded and bear scale markings 4 which co-act with a reference line'4a scribed on a contiguous I complementary plate 5. Bracket bearings 6 and I extend upwardly from the base structure 2 and support a rockable shaft 8.

Journaled freely rotatable on the en 7 of the rockable shaft remote from the pivot pin The 7 The headstock arms are, fixedly secured at their lower ends to the rocki able'shaft 8 and their upper ends form coaxial bearings |3a and Ma which receive and support rotatably the headstock spindle l2.

The end of the headstock spindle l2 above the pivoted end of the base frame 2 is provided. with .a control cam collar which is adapted to carry The control cam is in the 1 form of disc secured to collar I5 by screws |'|,'and

j the periphery of the cam is shaped to cause move- 5 ment of the workpiece to and from the. grinding wheel during the course of revolution, as will be describedin more detail hereinafter. 1 may have any outline, depending upon the char- 1 acteristics desired to be given the workpiece. A cam outline specifically designed to grind certain cutting tools or workpieces with a'clear- The cam ance angle appears in Figs.,6 and '7.

The headstock spindle l2 is provided with a I bore [8 therethrough, and its end portion beyond the flange I5 is threaded as indicated at l9 (see i Figure 4) to accommodate various conventional work holding devices such as a jaw chuck shown in Figdl, or a collet chuck2| as shown in Fig. 4. In the latter case the collet chuck receives collets 22 adapted to be tightened by a suitable tension tube 23. Other work holding devices and jigs may of course be employed depending upon the nature of the workpiece W (see Figures 1, 5,6and7).

A cam roller 24 bears on the periphery of the control cam It at a point substantially tangential toan are having its center originating at the rockable shaft 8. The cam roller is mounted at the upper endof a rigid post 25 which extends along the side of the headstock arm [4 and" is secured at its lower end to the base frame 2 so that the roller 24 occupies a fixed position with respectto the base structure 2. A horizontal stem 26 is pivotally connected at 2'! to the head-. stock arm I4 and extends outwardly therefrom through an openin in the post. The extended end of the stem is provided with a head and between the head and post 25 is a heavy spring 28 which, acting against the post 25, draws the entire headstock assembly comprisinghe adstocki arms I3 and I4 and headstock 'spindle l2'towa'rd the post and causes theperiphery of the sem s; to bear against the roller: 24. h a consequence; the headstockspindle and'the workpiece W eard portion.

' 4 ried thereby are moved laterally to and from the grinding wheel G.

Sometimes it is desired to mount a relatively long workpiece between the headstock spindle and a tailstock spindle and to move such work piece bodily to and from the grinding wheel. This is accomplished by means of an extension 29 of the rockable shaft 8 which is supported by bracket bearing 30. Normally the extension 29 is in coaxial relation with the rockable shaft 8; however, topermit pivotal movement of the base frame 2 about the pivot pin 3, a universal joint 3| connects the rockable shaft 8 and its extension 29. Ifdesired, the two shafts may be merely capable of disconnection at this point for the tailstock is not employed in conjunction with the headstockexcept when the two shafts 8 and 29 are coaxial.

The extension 29 of the rockable shaft 8 has secured thereon a tailstock arm 32 which car ries a tailstock spindle 33 or other conventional work supporting tool or fixture, 1 7 Operation of my grinding machine isas follows:

1. Grinding cylindrical objects.--The head'- stock and tailstock spindles are disposed'in alignment; that is, the base structure 2. is in its 0 crneutral straight line position. A plain circular disc concentric with respect to the workpiece is employed in place of the control cam It. The workpiece is then rotated while the grinding wheel is moved into engagement with the work' piece and either the grinding wheel or work bed is moved longitudinally within the region of the work to be ground. If the workpiece be long, it is supported between both the headstock and tailstock spindles; otherwise it need be held only by the headstock spindle. v

2. Grinding noncylindrical objects.-If the surface to be ground is parallel to the axis of rotation, the workpiece is mounted as in the first mode of operation described above, with the exception that a cam |6 having a predetermined variation in radius 'is substituted. For example,

in order to grind the lands 4| of a tap or an end mill 42, indicated diagrammatically in Figs 5 and 6, a controlcam l6 having a periphery of the general shape indicated at 43 may be used. In such operation the object is to give the lands proper clearance angle. The portions 44- of the cam, subtended by the same central angles as the lands 4 I are of gradually increasing radius in the direction of rotation, the difference in radii at the beginning and end point of said portions being of course equal to the depth to which the trailing edges of the lands are to be ground as compared with the forward edges thereof topmvide the desired clearance angle. Figs. 5 and 6' show the clearance angle of the lands 4| and the corresponding shaping of the cam 43 with some exaggeration for clarity of illustration. In

Fig. 5, the parts are shown just before one of the lands 4| engages the grind wheel, and just before the cam' portion 44 engages the roller 24. At a position just beyond that of Fig. 5, the leading portion of the land 4| engages the grind wheel, and the cam portion 44 reaches the roller 24. As the portion 44 of the cam then moves across the roller 24, the entire working assembly including headstock spindle l2, arms [3 and. M, and the workpiece moves gradually towards the grind wheel, thus grinding the land 4| with the clearance angle desired." Fig.6 shows the. parts with the trailing edge portions or heels of the land being ground, and just about to sepa-;

rate from the grind wheel. The portions 45 of the cam between portions 44 merely connect the latter and serve to return the workpiece to the proper position for the beginning engagement of the next land with the wheel G.

3. Grinding a tapered surface.-+A tapered surface is ground in the manner of the first or second mode of operation described above with the exception that the base plate 2 is set horizontally at an angle.

diverge or converge toward its extremity. Thus, the end of a tap may be ground with a taper towards its extremity; whereas, an end mill or router may be ground so that it diverges towards its extremity. In such a mode of operation, the tailstock is not employed. If the workpiece is relatively long, however, it may be desired to support it by the tailstock. In this type of operation the base plate 2 is placed on a centered position on the work bed I, and the latteris pivoted as a whole to the necessary angle relative to the grinding wheel on the previously-mentioned vertical pivot 3 with which the work beds of grinding machines are conventionally provided.

4. Grinding internal surfaces-For such operations, the grinding machine may be set up as for any of the operations 1, 2 or 3 described above. In place of the grinding wheel G, an internal grinding wheel or spindle I, represented diagrammatically in Fig. 7 is employed. The internal grinding wheel or spindle is, of course, small in diameter to fit Within the socket or bore to be ground and is supported by any suitable conven tional means, not shown. In Fig. '7, for purposes of illustration, a control cam I6 having a special surface 5| is hown shaped to cause the grinding of a square opening 52 in a workpiece W. Other internal shapes may be as readily ground by proper shape of the control cam.

By reason of the fact that the control cam It is mounted coaxially with respect to the Workpiece and is adjacent thereto and rotates therewith, it is a simple matter to adjust the phase relation 0r angular position of the workpiece with respect to the control cam.

As indicated in the foregoing description, the Work bed proper and grinding Wheel G themselves together with their directly associated elements may be conventional, in which case my frame structure 2 and its associated part are, in eifect, an attachment. However, it is of course obvious that the work bed and grinding wheel together with their associated elements may be specially This may be at a slant in either one direction or the other so that the workpiece may designed so that the Whole may constitute a complete machine entity, a distinguished from an accessory or attachment.

While I have now described a preferred specific illustrative embodiment of the invention, it is to be understood that the invention is not limited to the exact illustrative machine as shown and specifically described, but that various changes in design, structure and arrangement may be made without departing from the spirit of the present invention or the scope of the appended claim.

Iclaim:

A grinding machine, comprising a headstock base structure pivotally mounted near one of its ends about a vertical axis, means for releasably securing said base structure in its angularly adjusted positions about its pivotal axis, a rockable shaft carried by said base structure and projected at one end over said pivoted base structure end, a headstock unit swingably secured to said rockable shaft above said headstock base structure whereby to be swung laterally of the axis of said rockable shaft upon a forced rocking movement of said shaft, a rotatable spindle iournaled on said headstock unit with its axis parallel to the axis of said rockable shaft, a control cam carried by and rotated with said spindle, a roller abutment positioned peripherally opposite said control cam and fixed stationarily with respect to the headstock base structure, spring means interposed between said roller abutment and said headstock unit for maintaining the control cam forcibly but yieldably in engagement with said roller abutment whereby said headstock unit is caused to swing in accordance with the peripheral configuration of said control cam, means on said headstock spindle for supporting and rotating a workpiece about the axis of said spindle, a grinding element cooperatively positioned and arranged and adapted for peripheral grinding engagement with the workpiece as supported on the spindle of said headstock unit in whatever angular position the headstock base structure may be adjusted about its pivotal axis, a laterally swingable tailstock unit, said tailstock unit being mounted on a rockable shaft supported and arranged as a continuation of the first-mentioned rockable shaft and normally in axial and a universal coupling between said first-mentioned and said last-mentioned rockable shafts, said coupling having its center in alignment with the pivotal axis of the headstock base structure.

JOSEPH A. CAMERON.

alignment therewith,

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