US3500588A - Surface grinder or related unit - Google Patents

Description

March 17, 1970 F. w. FISCHER 3,500,583

SURFACE GRINDER OR RELATED UNIT Filed Dec. 5. 1966 2 Sheets-Sheet 1 "'1' FIG.I

INVENTOR. "FRED W. FISCHER BY r ATTORNEYS March 17, 1970 F. w. FISCHER SURFACE GRINDER OR RELATED UNIT 2 Sheets-Sheet 2 Filed Dec. 5, 1966 ill INVENTOR. FRED W. FISCHER Illllll llllllllllllH I I l l I FIG.4

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ATTORNEYS United States Patent 3,500,588 SURFACE GRINDER OR RELATED UNIT Fred W. Fischer, 1450 Silver Bell Road, Rochester, Mich. 48063 Filed Dec. 5, 1966, Ser. No. 599,108 Int. Cl. B24b 7/10 U.S. Cl. 51119 12 Claims ABSTRACT OF THE DISCLOSURE A power spindle rotatively drives a tubular housing encircling the spindle, the drive being through a universal ball and socket connection; and the housing carries a cutting tool. An adjustable wedge-type slide plate in turn cases the rotating housing to have a continual oscillatory motion eccentric of the spindle axis, thus compounding this action at the tool with a spindle-derived rotative action. A separate power source drives the housing for the oscillatory motion; and the slide plate has cam means to adjust it and the path of the oscillatory motion during the operation of the tool.

The present invention relates to a unit to perform an improved surface grinding or related type of material removing or treating operation on workpieces. More particularly, the unit of the invention is one which is intended to be applied as an adapter to a known type of surface grinder head (although its application to equipment for the milling, polishing etc., of objects is also contemplated), and thereby produce an improved, compounded and oscillatory action of the rotary wheel of the head on the workpiece. A typical head to which the improved unit of the invention may be readily applied is the Model No. 24 grinder of Mattison Machine Works of Rockford, Ill.

This type of grinder equipment features a so-called quick tilt head for the successive performance of rough and finish grinding cuts; and the arrangement is such that for initial rough grind the power spindle of the wheel is tilted a very slight amount relative to the vertical (in an upright spindle machine), thus to produce a departure of the grinding surface from the horizontal amounting to, say, 0.010 inch. In the final, finish cutting phase, the wheel is restored to true horizontal parallelism with the work surface being ground.

The purpose of the quick tilt arrangement is to get rid of metal or other particles removed from the workpiece in the rough cut, as well as broken down grit, while the cut is being made. It is, however, characteristic of this tilt type of equipment that the wheel attacks the workpiece, as the latter is held by a magnetic or like rotary chuck, solely at a peripheral wheel edge at the commencement of the cut, i.e., adjacent the center of the chuck, the Wheel progressively taking flush surface engagement with the workpiece surface (in a radially outward sense) as material removal proceeds. The result is that the rough-ground surface has a slightly dished or concavely coned shape.

On the other hand, during the finish grinding phase, the attack of the wheel on the rough-ground surface is progressively in the opposite direction, i.e., from the rim of its dish toward the center of the chuck, until the wheel surface again comes in flush parallelism with the ultimately ground finish surface. The result is that, although the conventional tilt-head feature is effective in dispersing metal particles and grit during rough and finish passes, the entire abrasive surface of the grinding wheel acts on the workpiece during only a portion of the elapsed time of the respective rough and finish grinding operation. This is inefficient, production-wise and, moreover, requires the expenditure of considerable power to Patented Mar. 17, 1970 ICC produce the finished product, as well as at a slower rate. For example, heads of a rating of HP are in common use. Still further, it is usually necessary to employ wheels of as much as five different hardnesses in the grinding of stock of different hardness, i.e., a soft wheel for a hard workpiece, and vice versa, within the work hardness range.

It is therefore an object of the present invention to provide an improved unit applicable to a conventional grinding or related material removing or treating head, which may be either a tilt head type or not, in which the wheel (and it may with comparable advantage be either a segmented or a continuous ring one), has a compounded oscillatory motion inengagement with the workpiece surface throughout the operation. It may be operated under heavy pressure for a fast cut, yet is not subject to objectionable heating, and gets rid of metal particles and fractured grit in the desired manner. It of course follows that the amount of metal or other material that may be removed in a grinding phase of given duration is multiplied; a much lesser horse power input is required. Rough and finish grinding may be performed on metals of the usual hardness range by operating in as little as two grades of wheel hardness.

Further in accordance with the invention, the grinding or other operating tool, as mounted generally concentrically of and driven at high speed by the power spindle of the conventional head, is nevertheless given an independent rotary motion at less speed by the unit, and about an axis a bit eccentric of the axis of the power spindle. Thus, since the lateral displacement of the eccentricity relative to the last named axis is continually changing, there results the mentioned oscillatory action of the tool on the workpiece surface. The action physically involves a slide-modified motion of an oscillatory housing on which the operating wheel is carried, which motion resembles that of a wobble plate or swash plate.

In still further accordance with the invention, the improved unit has means to adjust the extent of the eccentricity during the grinding operation, thus enabling the extent of throw of the oscillation-imparting component to be quickly varied, should need arise.

Another object of the invention, in a more specific aspect, is to provide a unit of the type described, in which the mount afforded by the unit for the grinding wheel includes a slide capable of a rectilinear adjusting movement transversely of the spindle axis. The adjustment is of small extent on a slide guiding and driving plate, which plate has a drive connection to an independent low speed power source. On the other hand, a motion-modifying connection of the slide to the wheel assembly is made through the agency of an elongated oscillatory housing and special universal means drivingly connecting the housing to the wheel.

Thus the guide and drive assembly, as rotated at slow speed from a source independent of the spindle drive, nuta'tes the slide eccentrically of the spindle axis, in turn continuously tilting and varying the direction of eccentricity of the oscillatory housing relative to the spindle axis to produce the compounded eflect referred to.

In further accordance with the invention, the special connection of the oscillatory housing to the spindle of the head is of a ball and socket type to accommodate the tilt and oscillatory shift of the housing and wheel driven thereby. The eccentrically disposed slide is also connected to the housing through special bearing means to accommodate the latters tilt in oscillation, and the housing has still further special bearing means journalling the same in a fixed housing part of the unit for the same purpose. There is continuous contact ofthe wheel with the workpiece regardless of the continuously changing inclination of the oscillatory housing axis to the spindle axis, which inclination or tilting arises from the essentric rotation of the housing-mounting slide relative to the spindle axis.

Pursuant to the invention the connection of a driving ball, drivingly connected to the power spindle, to the oscillatory housing and operating wheel is a key-like one which will permit the desired ball and socket action, being preferably in the form of an annular series of small balls, each drivingly received in an arcuate recess in the periphery of the main driving ball, at a diameter thereof, and drivingly connected through the socket to the oscillatory housing.

A further specific object of the invention is to provide a unit in which the eccentricity of the slide may be readily and accurately adjusted through the agency of inclined wedge surfaces on opposite outer ends of the slide, which surfaces matingly engage correspondingly inclined wedge surfaces of a special slide adjusting ring. This ring is rotatively driven, along with the slide, by the guide and drive plate for the latter; and provision is" made to vary the relative position of the respective wedge surfaces in a direction paralleling the rotative axis, by shifting the adjusting ring axially, with the result that the slide is wedged or cammed along its guide and drive plate, in one direction or other at 90 to the axis. This provides a simple means for accurately adjusting the eccentricity of the slide and oscillatory housing axis relative to the spindle axis for the purpose described above.

"In further specific accordance with the invention the means for effecting the slide adjustment is such that it may be operated readily from an external point and while the grinding or other finishing or treating operation proceeds. Such means takes the form of an externally threaded, rotatively fixed but axially shiftable annular screw member of large diameter, which screw member is in threaded engagement on its periphery with ari annular rotatable, internally threaded elevating and depressing nut member. Annular rack and pinion-type means enable the last named member to be rotated during the work finishing operation, thereby raising or lowering the screw member; and the latter is operatively connected to the slide adjusting ring to effect the desired slide adjusting wedge action as the result of a vertical shift of the adjusting ring by the elevating and depressing. screw member.

In still further accordance with the invention, the slide guide and drive plate, as slowly rotated on an axis eccentric of that of the spindle by a power source independent of the main spindle power input source, is drivingly connected to said independent source by a rack and pinion-type connection. The source is a variable speed motor of relatively small power rating, since the load is small.

The foregoing, as well as other objects, will become more apparent as this description proceeds, especially when considered in connection with the accompanying drawings illustrating the invention, wherein:

FIG. 1 is a fragmentary view in vertical section, as in the plane 1.1 of FIG. 2, through the rotative axes oft he improved unit and the power spindle of a conventional grinder head to which the unit is applied as an adapter, the view generally indicating in solid and dotted lines'two positions of adjustment of an elevating and depressing ring of the unit in producing a wedging rectilinear adjustment of a slide rotatively driven by a slide guide'and drive plate, thus to adjust eccentricity as men- ;ioned :above;

FIG. 2 is a fragmentary view, partially broken away, n horizontal section on line 2-2 of FIG. 1;

FIG. 3 is a view in vertical section of the elevating rnd depressing ring above referred to, as on Section line l-3 of FIG. 2; and

FIG. 4 is a view in section similar to FIG. 3 of the assembled slide and its guide and drive plate.

Referring to FIG. 1, a portion of a Model 24 Mattison grinder head of the quick-tilt type is generally designated by the reference numeral 10. The parts appearing in that figure include a motor housing 11 having an annular bottom boss 12, in a bore of which a lower bearing cartridge 13 encasing lower spindle ball bearings 14 is concentrically received. These rotatively journal the lower end of an elongated drive spindle 16, which will be operated at high speed by a motor (not shown) of, say, 75 HP rating.

The reference numeral 18 generally designates an improved head adapter or conversion unit of the present invention, which will presently be described in detail; and the reference numeral 20 generally designates a typical grinding wheel assembly of unit 18. This assembly is shown as being constituted by a continuous cylindrical abrasive wheel 21 suitably mounted to an annular steel backing ring 22. Ring 22 is received in an annular recess 23 of equal dimensions about the periphery of the bottom of a special mounting body 24 of unit 18. A workpiece W is shown as being mounted on the top of a rotary magnetic chuck C; the axis of rotation is shown at A. It is, of course, to be understood that other types of work holder may be employed, also that the wheel 21 may be a segmented or other type known to the art.

In accordance with the invention, the wheel body 24 is formed to provide a center quasi-spherical recess or seat 25 of substantial diameter and coaxial with wheel assembly 20; and this recess matingly receives the bottom half 26 of a socket 27. Socket half 26 is drivingly connected appropriately in a fired manner to wheel body 24, and presents an internal and upwardly facing, quasispherical socket surface 28.

The upper half of the socket 27 is the form of an integral formation 31 at the bottom of an axially elongated and otherwise cylindrical oscillatory housing 32 of substantial diameter. Housing 32 surrounds the spindle 16 with substantial radial clearance at 33 and serves important functions other than of affording the formation 31, as will appear.

The last named formation has a quasi-spherical internal and downwardly opening socket surface 35 of the same radius as bottom socket surface 28, so that when the oscillatory housing 32 and bottom socket member 26 (which in effect completes the housing) are secured in axially aligned, face to face engagement with one another, as by a series of screws 36, the surfaces 28 and 35 constitute a universal joint to receive a quasi-spherical ball 38 of the same diameter. Ball 38 is conically bored from above and counterbored at its bottom to matingly receive the usual conical nose of spindle 16, as well as a bolt 39, which bolt threads upward into the spindle nose to lock ball 38 to the bottom of the latter. A driving connection between the spindle and ball is provided at a key 40 on the former; the ball is in turn drivingly connected to the socket 27, as constituted by members 26 and 31, through the agency of several small antifriction bearing balls 41, which permit a swivel action of oscillatory housing 32 of drive ball 38.

Thus, each bearing ball 41 is received in part in an upright arcuate groove 42 formed in ball 38 at a horizontal diameter plane thereof, and in part in a semispherical seat 43 formed at the meeting line of socket members 26 and 31. Accordingly, the ball and socket members afford a universal driving connection between spindle 16 and the wheel assembly 20 for the primary rotative drive of the latter, the drive transmitting balls 41 allowing a slight swivel of the wheel assembly relative to the axis of spindle 16. This is important in relation to the eccentrically driven motion in operation of the oscillatory housing.

The wheel mounting body 24 and socket member 26 are centrally apertured at 45, coaxially of the locking bolt 39, for convenient access to the latter. It is of course contemplated that the unit 18 of the invention is of equal utility and merit when applied to a head whose spindle operates on a horizontal or other than vertical axis.

The unit 18 includes a fixed housing 47 of considerable diameter which is internally belled at its lower portion, the oscillatory housing 32 extending upwardly through a circular throat 48 of housing 47. The lower, skirt-like portion of that housing 47 receives the outer race of a special ball bearing 50 of quite large diameter; the inner race of this bearing being fixedly mounted to the universal socket structure 26, 31 at the diametral zone at which its two component portions meet. Ball bearing 50 is, as a significant feature of the invention, one whose race surfaces 51 are slightly arcuate and concentric, thus to permit a slight swiveling tilt of oscillatory housing 32 relative to the spindle axis, just as the driving balls 41 permit a tilt of that housing and wheel assembly 20 relative to the same axis. This ties in with the eccentric drive of housing 32.

Reference being had to FIGS. 2, 3 and 4 in conjunction with FIG. 1, the upper cylindrical end of the oscillatory housing has a splined or like fixed driving connection 53 at its top with the inner race of a second ball bearing 54 of somewhat smaller diameter than the lower bearing 50; and bearing 54 also has slightly arcuate and concentric race surfaces 55 which will permit a slight tilt of oscillatory housing 32 relative to the axis of spindle 16, for the eccentricity-accommodating action mentioned above.

The outer race 56 of ball bearing 54 is fixedly secured in a cylindrical opening of an eccentricity adjusting slide or slide plate 57 which, as best shown in FIGS. 2 and 4, has diametrically opposed outwardly convex ends of corresponding arcuate extent. These ends are formed to provide parallel wedge surfaces 59 and 60 about their respective arcuate lengths; and the wedge surfaces 59, 60 are subtended by parallel upright and rectilinear side surfaces 61, 62 of slide 57. For the purpose of convenience, as viewed in FIG. 4, wedge surface 59 may be considered to be undercut or downwardly relieved and the opposite wedge surface 60 to he beveled or upwardly relieved. These surfaces 59 and 60 function importantly in the adjustment of the axis of eccentricity of oscillatory housing 32 in action, hence of the various drive parts and wheel assembly 20 which are carried thereby.

The slide 57, and the ball bearing 54 through which it is operatively spline-connected to the top of oscillatory housing 32, are slidably guided for their slight rectilinear adjusting movement on the top of a special circular slide guide and drive plate, generally designated by the reference numeral 64. This plate has an integral annular, downwardly projecting flange or shoulder 65 surrounding a central bore 66 which has substantial radially outward clearance at 67 from oscillatory sleeve 32.

Flange 65 slides rotatively on a top surface of the fixed housing 47 surrounding the latters bore 66; and ball bearings 68 outwardly journal the plate flange 65 for this rotation, acting between the latter and an upright cylindrical wall 69 of housing 47. Provision is made outwardly of this wall for the independent rotative drive of plate 64 at relatively low speed, as will be later described.

Referring particularly now to FIGS. 2 and 3 in conjunction with FIG. 1, the plate 64 is provided witlia wide, upright-walled recess of substantial axial depth across its upper surface, the recess being defined by parallel side walls 71 (FIG. 2); and the sides 61 of slide 57 are guided for rectilinear eccentricity adjusting movement between these walls, with the slide also having a rotative drive from the recess walls 71 at a relatively slow speed as compared with that of the spindle 16 and wheel assembly 20.

Referring to FIG. 1, the fixed housing 47 of unit 18 includes an annular horizontal and radially outwardly extending flange formation 73 which has an annular upright outer confining rim or shoulder 74. A cover plate 75 of relatively large diameter is secured downwardly upon this shoulder by a series of set screws 76; and cover plate 75 confines the slide 57 and special bearing 56 from above, as well as other adjusting components to be described, while permitting free rectilinear adjusting shift of the slide. An adapter plate 78, to which cover 75 is connected by screws 79, is in turn upwardly connected by screws or bolts 80 to the bottom of the annular boss 12 of the housing 11 of head 10.

Slide 57 is operated directly in its adjusting action by a flat adjusting ring of large diameter, generally designated 82, of a special kind, which is best illustrated in FIG. 3. It is cylindrical on its exterior, save for the :presence of a small outwardly projecting annular flange 83; 'and it is also generally cylindrical on its interior surface 84, save for the presence of inclined wedge surfaces 85, 86 in diametrically opposite end zones thereof which are, like slide wedge surfaces 59, 60, also of substantial arcuate extent. Inclined surfaces 85 of slide 57 hence may be considered to be downwardly and inwardly beveled, while the opposite surface 86 has a similar mating coaction with the slide wedge surface 60', hence may be considered to be downwardly undercut. At opposite arcuate ends of the wedge surfaces 85, 86 the same meet opposite upright end walls 87 in the bore of adjusting ring 82; and the extremities of opposite sides 61 0f slide 57 are received within and guided by these parallel upright wall components 87, just as the remainder of the slide sides are guided between the recess walls 71 of guide and drive plate 64.

Thus, as guided for rectilinear adjusting action by walls 71 and 87, with its wedge surfaces 59, 60; respectively engaging the surfaces 85, 86 of slide guide and drive plate 64, the slide 57 is also rotatively driven on an upright axis by those walls.

As indicated above, the wedging adjustment is made as the result of relative movement of the pairs of adjusting ring and slide wedge surfaces 59, 85 and 60, 86 in a direction parallel to the axis of spindle 16. More specifically, since the slide 57 is restrained by cover plate 75 against vertical movement, it is the adjusting ring 82 which is shifted in the axial direction; and this is done through the agency of the integral annular side flange 83 of the ring.

As best shown in FIG. 1, a pair of large diameter annular and threadedly engaging adjusting screw and nut members 88, 89, respectively, coact with ring 82 for the purpose, the screw member 88 being externally threaded for coaction with internal threading of the nut member 89 at 90. Member 88, which is held against rotation in the adjustment (member 89 being rotated by means to be described), has an internal annular, flange-like shoulder 91; and the side flange 83 of adjusting ring 82 rests and runs on shoulder 91. An annular retaining ring 93 is secured from above onto said adjusting screw member 88, acting to restrain flange 83 from above, but with a running clearance relative tothe later.

As best shown at the right of FIG. 1 (reference also being had to FIG. 4), the adjusting screw member 88 is restrained against rotation on the flange 73 of fixed housing 47, as by a series of axially extending dowels 95. These extend through bores in member 89 and into the fixed flange 73 and cover plate 75.

Adjusting ring 88 is of the nature of a special ring gear, in that it has a circumferential series of gear or rack teeth 96 formed on and about its bottom. These teeth are meshingly engaged by a. pinion 97 fixed on a small, radially extending and rotatable shaft 99, which shaft extends outwardly of fixed housing shoulder 74 through a bushing 100 in the flange 73 of which the shoulder is a part. Shaft 99 has a hand wheel 101 secured on its outer end.

Accordingly, a rotation of hand wheel 101 in one direction or another causes a corresponding rotation of adjusting nut member 89, accompanied by axial shift of the rotatively fixed annular adjusting screw member 88; and the adjusting ring 82 is correspondingly elevated or lowered. There is an attendant wedging adjustment of slide 57, horizontally in one direction or another, to vary the eccentricity of oscillatory housing 32 at its cylindrical bore space 33 relative to the axis of spindle 16; and as the latter drives wheel assembly 20 at high speed through the agency of ball 38, the constantly changing slide eccentricity (in relation to'the spindle axis) is superposed as a reciprocatory and nutative component on the normal rotation of housing 32 and wheel assembly 20, resulting in the desired oscillatory action of the latter.

The motion of oscillatory housing 32 resembles that of a wobble plate or swash plate; and as indicated above, the special bearing provisions associated with oscillatory housing at ball 38, socket 27 and bearings 41, 50 and 54 permit the tilting shift of housing 32 relative to spindle 16.

It is to be seen that the adjusting of slide and housing eccentricity may be made while grinding is taking place, .due to the use of the adjusting ring, screw and- nut members 82, 88, 89, respectively.

The compounded oscillatory action of wheel assembly 20 of course involves importantly the independent rotative drive of the slide 57 by plate 64 at the top recess of the latter, and the attendant rotative drive of adjusting ring 82 within rotatively fixed adjusting screw member 88. To this end, the plate 64 is equipped at its bottom and about its circumference with a series of downwardly extending rack or gear teeth 104 (FIGS. 1 and 4), which are meshingly engaged by a small pinion 105 located just radially outwardly of upright wall 69 of fixed housing 47 and the radial bearings 68. Pinion 105 is fixed on a radially elongated shaft or spindle 106 which is journaled in a bushing 107 in the fixed housing flange 74; and shaft 106 is driven independently of the drive or power spindle 16, and at much lower speed than the latter, as by a variable DC motor (not shown) rated from 5 to 50 rpm.

Accordingly, with the slide guide and drive plate 64 so driven, and so driving the slide 57, the eccentricity of oscillatory housing 32, as connected by bearing 54 to the slide, is continuously altered at the housing-to-spindle clearance space 33 (FIG. 1) with resultant production of the'improved oscillatory action contemplated by the invention. Axial movement of adjusting ring 82 is accommodated in an annular bottom recess 109 in cover plate 75. a

It is seen from the above that the invention affords a unit capable of being readily applied to a conventional type of grinder or other powered operating unit, as a conversion or adapter device for such a head, which unit substantially and significantly modifies the working action of an operating wheel assembly of the unit on a workpiece. A compounded oscillatory characteristic is imparted to the wheel assembly which is of great utility in improving the grinding or other action. That is, the wheel is kept continuously in engagement with the workpiece, in an action which sweeps away metal particles and grit dislodged from the wheel. Increased operating pressures may be employed, but without creating objectionable heat. The duration of the grinding operation is diminished; and these advantages are obtained with a significantly decreased input of power at the spindle of the head, as compared with what is commonly employed in known type equipment.

What is claimed is:

1. In a grinding or related unit which is adapted to be driven in operation by a grinder or related type power head to operate upon a flat surface of a work-piece, said units having means rotatively driven by an output member of the head and supporting an operating tool member to ingage the latter wi h said workpiece surface at the plane of said surface; the improvement in accordance with which said unit comprises relatively driven means to compound the rotation of said output member, as applied to said tool member, with a generally oscillatory, onbitally traveling motion of the latte-r in its said engagement with the workpiece at said surface plane, and means operatable during the operation of said unit to adjust the orbital path of said oscillatory motion.

2. The unit of claim 1, in which said motion compounding means comprises means drivingly connecting said output and tool members and acting to impose an eccentric component of limited throw upon the rotary motion of the output member to produce said oscillatory motion of the tool member.

3. The unit of claim 1, in which said motion compounding means comprises means drivingly connecting said output and tool members and acting to impose an cecentric component of limited throw upon the rotary motion of the output member to produce said oscillatory motion of the tool member, and means to produce said eccentric component from a source independent of the power drive of said head.

4. The uni-t of claim 3, said last named means comprising means to adjust the extent of said eccentric throw.

5. Ina grinding or related unit which is adapted to be driven in operation by a grinder or related type power head, said unit having means rotatively driven by an out- .put member of the head and supporting an operating tool member to engage the latter with a workpiece; the improvement in accordance with which said unit comprises means to compound the rotation of said output member, as applied to said tool member, with a gene-rally oscillatory motion of the latter in its said engagement with the workpiece, and means operable during the operation of said unit to adjust the path of said oscillatory motion, said motion compounding means comprising means drivingly connecting said output and tool members and acting to impose an eccentric component of limited throw upon the rotary motion of the output member to produce said oscillatory motion of the tool member, said means imposing said eccentric component comprising a slide and means guiding said slide for a rectilinear adjustment at to the axis of rotation of said output member of the head, said guide means and slide having means driving the same on an axis eccentriepf that of said rotative output member.

6. The unit of claim 5, in which said adjusting means comprises coacting wedge surfaces on said slide and its gu de means to variabley shift the slide transversely of said eccentric axis upon relative movement of the wedge sfiiffaces in a direction normal to that of the variable s Y t.

7. The unit of claim 5, in which said throw adjusting means comprises coacting wedge surfaces on said slide and its guide means to variably shift the slide transversely of said eccentric axis upon relative movement of the wedge surfaces in a direction normal to that of the variable shift, and means to effect sa-id relative movement of the wedge surfaces during said workpiece engaging motion of the tool member.

8. The unit of claim -1, in which said adjusting means comprises coacting movable members, one of which engages a part of said mechanism which supports the tool member to make the adjustment and the other of which operates said one member, and means to actuate said other member from the exterior of the unit.

-9. The combination with a grinder or related type power head of mechanism rotatively driven by an output member of said head and supporting an operating tool member to operate upon a flat surface of a workpiece at the plane of said surface, said mechanism comprising rotatively driven means to compound the rotation of said output member, as imparted to the tool member through the mechanism, with a generally oscillatory, orbitally traveling moiion of the latter in its engagement with the workpiece at said surface plane, and means operable during the operation of said tool member to adjust the orbital path of said oscillatory motion.

10. The combination of claim 9, in which said adjusting means comprises coacting movable members, one of which engages a part of said mechanism which supports the tool member to make the adjustment and the other of which operates said one member, and means to actuate said other member from the exterior of the unit.

11. The combination with a grinder or related type power head of mechanism rotatively driven by an output member of said head and supporting an operating tool member, said mechanism comprising means to compound the rotation of said output member, as imparted to the tool member through the mechanism, with a generally oscillatory motion of the latter in its engagement with a workpiece, and means operable during the Operation of said tool member to adjust the path of said oscillatory motion, said compounding means comprising a slide and means guiding said slide for a rectilinear adjustment at 90 to the axis of rotation of said output member of the head, said guide means and slide having means driving the same on an axis eccentric of that of said rotative output member.

12. The combination of claim 11, in which said adjusting means comprises coacting wedge surf-aces on said slide and its guide means to variably shift the slide transverse-1y of said eccentric axis upon relative movement of the wedge surfaces in a direction normal to that of the variable shift.

References Cited UNITED STATES PATENTS 1,343,050 6/ 1920 Goodwin 51-1-20 2,105,634 1/1938 Brendel 5l119 X 3,212,373 10/1965 Basso 2796 X 2,975,565 3/196'1 Phillips 51--124 HAROLD D. WHITEHEAD, Primary Examiner US. Cl. X.R. 5l134.5

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