US3598100A

US3598100A - Dresser structures

Info

Publication number: US3598100A
Application number: US803751A
Authority: US
Inventors: Thomas A Deprez; Alvin W Snook
Original assignee: Gleason Works
Current assignee: Gleason Works
Priority date: 1969-03-03
Filing date: 1969-03-03
Publication date: 1971-08-10
Anticipated expiration: 1988-08-10
Also published as: FR2033055A5; GB1274582A; CH528337A; DE7006204U; DE2007973A1

Abstract

Rotary dresser structures are described with specific reference to novel characteristics for dressing cup-shaped grinding wheels of the type which are useful for grinding teeth in face couplings. The dressing structures include a pair of rotary dressers for shaping and dressing side surfaces of the cup-shaped grinding wheel together with a third rotary dresser which dresses an annular end of the grinding wheel. The dresser structures which will be described are especially useful for precision dressing and for grooving grinding wheels which are to be used in high heat formation grinding operations.

Description

United States Patent Inventors Thomas A. Deprez; 7%

Alvin W. Snook, both of Rochester, N.Y.

Mar. 3, 1969 Aug. 10, 197 1 The Gleason Works Rochester, N.Y.

Appl. No. Filed Patented Assignee DRESSER STRUCTURES 17 Claims, 22 Drawing Figs.

US. Cl.

lut- CL.

Field of Search References Cited UNlT ED STATES PATENTS 7/1926 Slade 1,689,565 10/1928 Trbojevich 2,360,127 10/1944 Harley Primary Examinerl-larold D. Whitehead Auorney-Cushman, Darby and Cushman ABSTRACT: Rotary dresser structures are described with specific reference to novel characteristics for dressing cupshaped grinding wheels of the type which are useful for grinding teeth in face couplings. The dressing structures include a pair of rotary dressers for shaping and dressing side surfaces of the cup-shaped grinding wheel together with a third rotary dresser which dresses an annular end of the grinding wheel. The dresser structures which will be described are especially useful for precision dressing and for grooving grinding wheels which are to be used in high heat formation grinding operations.

PATENTEUAUBIOISYI 3.598.100

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sum 15 0F 15 I INVENTORS 7% 0/445 fl. Dzpmez ATTORNEYS DRESSER STRUCTURES BACKGROUND AND BRIEF DESCRIPTION OF INVENTION This invention relates to improvements in means for dressing grinding wheels, and in particular the invention provides for rotary dressers having capabilities of precisely controlling contour and length of a cup-shaped grinding wheel. The rotary dressers include shaped heads having abrasive surfaces which are preferably formed by cementing diamond particles onto the work-engaging surfaces, and the rotary dressers are provided with mounting and adjustment means for care fully controlling contact of the dressers with a grinding wheel during periodic dressing operations of the grinding wheel. In addition, an assembly of dressers is provided for presenting a pair of dressers to opposite side surfaces of a cup-shaped grinding wheel, and a third-dresser makes contact with an an- 7 nular edge of the grinding wheel. The three dressers are related to one another in such a way that the grinding wheel can be grooved on its sides and its annular end to improve its grindingcharacteristics when it is being used in high heat formation operations with a coolant.

It is known in the art of dressing grinding wheels and other members to provide for single point diamond dresser structures which can control the: profile of a cup-shaped grinding wheel member. In fact, single point dresser structures of the type shown'in US Pat. No. 2,409,240 have become almost the only means ofdressing certain forms of grinding wheels in certain gear cutting operations. However, it is also known to provide dresser structures in the. form of rotary dressers which can contact a grinding wheel to shape the wheel in accordance with rotating heads of such dressers. Rotary dressers have been designed and constructed to provide rotating abrasive surfaces which can contact and shape members, and it is known to form the abrasive surfaces of a rotary dresser by cementing or setting small particle diamonds onto the surfaciwhich must engage a grinding wheel or other member;-

The present invention offers mounting and adjusting structures for rotary dressers which are especially adapted for precisely dressing cup-shaped grinding wheels of the type that may be used in grinding teethon. face gears and couplings. A typical machine and method of operation for such grinding is disclosed in my copending application entitled, Apparatus and Method for Grinding Toothed Face Members," as filed even date herewith, by the assignee ofthis application.

In accordance with the present invention, very stable and precisely positionable support structures are provided for three separate dressing units. Two of the dressing units function as a pair of dressers which simultaneously contact opposite annular sides of a cup-shaped g'rinding'wheel, and the third dresser unit may be brought into simultaneous engagement with an annular end surface of the grinding wheel. The mounting and support arrangements which are provided by this invention assure extremely precise and stable dressing operations which can be set and adjusted for the type of geometric accuracy and surface finish which are required for periodic dressing of cup-shaped grinding wheels useu in gear cutting operations. As is well-known, rotary dressers present special problems of deflection and vibration, as compared to the more commonlyused single point dressers, however, the structures of the present invention overcome problems which are normally expected'from rotary dresser usage. By utilizing rotary dressers, with the precision arrangements offered by this invention, it is-possible to dress a grinding wheel at a much higher rate of speed than would be the case with single point dressers, and also, unusual surface finishes and configurations can be obtained for the first time..ln the specific use for which the present invention is intended, as described in the above mentioned copending application, it has been found that a grooved configuration can be placed on a grinding wheel to improve its cooling characteristics while it is being used in high heat formation grinding operations. Such operations may speed grinding, the result of removing relatively large amounts of material from large workpieces, or grinding exotic materials of extreme hardness, but whatever the reason, it is desirable to maintain the grinding wheel in a cool and safe condition while the grinding operation is taking place. By dressing the grinding wheel with a grooved configuration, it is possible'to move a greater quantity of coolant liquid into the grinding zone while the grinding wheel is engaging a workpiece. The rotary dresser structures of this invention can be used to automatically effect such a grooved configuration on a cup-shaped grinding wheel while simultaneously dressing remaining surfaces of the grinding wheel to very precise tolerances and shapes.

' With three separate dresser units related to one another as provided by the present invention, it is possible to control the effective length of a cup-shaped grinding wheel independently of controlling the precise contour of the grinding wheel. In addition, the three dresser units of this invention can be adapted for either rough or finish dressing of a grinding wheel, and repair and replacement of dressing heads can be accomplished with a minimum of shutdown time for a grinding machine and with assurance of a prescribed contour or adjustment being repeated with a replacement unit.

These and other advantages of the present invention will become more apparent in the detailed description which follows, and in that description reference will be made to the accompanying drawings as briefly described below:

BRIEF DESCRIPTION OF DRAWINGS FIG. I is a front elevational view of a grinding machine of a type for which the dresser structures of this invention are especially useful;

FIG. 2 is a front elevational schematic view showing basic components ofa pair ofdresser units ofthis invention;

FIG. 3 is a top plan view of what is shown in FIG. 2 together with a view of a third dresser unit of this invention;

FIG. 4 is a view of FIG. 2, as seen from line 4-4 of FIG. 2;

FIG. 5 is a front perspective view of three dresser units of this invention, as mounted on the machine shown in FIG. 1;

FIG. 6 is a rear perspective view of what is shown in FIG. 5;

FIG. 7 is a partially exploded perspective view of the first and second dresser units shown in FIG. 5 as seen from the'bottom of the assembly;

FIG. 8 is a further exploded view of'the assembly shown in FIG. 7;

FIG. 9 is a top plan view showing details of a pair of dresser units, and adjusting means therefor, in a detailed embodiment of this invention;

FIG. 10 is a side elevational view of the embodiment shown in FIG. 9',

FIG. 11 is an end view, partially in section, as seen on line 11-11 of FIG. 9;

FIG. 12 is an end view as seen on line 12-12 of FIG. 11;

FIG. 13 is an end view, partially in section, as seen on line 13-13 ofFIG. 11;

FIG. 14 is a perspective view, partially exploded, of a third dresser unit in accordance with this invention;

FIG. 15 is a perspective, taken at a different angle than the view of FIG. 14, showing exploded details of the third dresser unit;

FIG. 16 is a top plan view, partially in section, showing a third dresser unit in a detailed embodiment thereof;

FIG. 17 is an end view of the embodiment of FIG. 16', as seen on line 17-17 ofFIG. 16',

FIG. 18 is a sectional view of a detail of construction of the third dresser unit;

FIG. 19 is a sectional view of a detail of construction of the third dresser unit;

FIG. 20 is a sectional view of a detail of construction of the FIG. 22 is a perspective view of an outside surface portion of a cup-shaped grinding wheel which has been dressed and grooved with the apparatus ofthis invention.

DETAILED DESCRIPTION OF INVENTION As mentioned above, this invention relates to improvements in structures for dressing grinding wheels, and the improvements are especially concerned with dressing cup-shaped grinding wheels of the type used for grinding toothed face members or pinions. The improvements of this invention provide a capability for automatically dressing a grinding wheel at periodic intervals during grinding operations, and the dressing functions are carried out by rotary dressers which have capabilities of precisely dressing a requisite profile on a grinding wheel while simultaneously dressing grooves into the grinding wheel if desired.

' Cup-shaped grinding wheels have been used for a number of grinding operations for producing toothed face members and other gear members. In a typical grinding operation, it has been the practice to oscillate the grinding wheel into and out of actual contact with a workpiece so that a coolant can be introduced into the grinding area to reduce heat and prevent burning of the workpiece and deterioration of the grinding wheel. Prior practice has also provided for a periodic dressing of the grinding wheel, usually with three single point dressing arms which shape the sidewalls and annular end of the cupshaped grinding wheel. However, single point dressers, consisting of single diamond points mounted for dressing engagement with a grinding wheel, have certain limitations in use because they require frequent adjustment to compensate for wear on the diamond point which is initially presented to a grinding wheel. Present day technology requires the grinding of relatively large workpieces and of workpieces which are made from especially hard metals, such as titanium, and these grinding operations produce relatively high levels of heat during actual engagement of the grinding wheel with the workpiece. In fact, the heat problem has become so great that it has become virtually impossible in certain grinding operations to oscillate a grinding wheel rapidly enough to maintain coolant in the grinding zone. A solution to this type of grinding problem is described in the above mentioned copending application with reference to a method for forming grooves or undulations into the sidewalls and the annular end of a grinding wheel so that coolant can be introduced into the grinding not while the grinding wheel is maintained in actual grinding con tact with a workpiece. However, the use of a grooved grinding wheel has created special problems of how to dress such 2 grinding wheel periodically during grinding operations so as I:

maintain a precise profile on the wheel while simultaneousl maintaining grooves on both sidewalls and the annular end of the wheel. In order to meet the needs of grinding techniques which utilize grooved grinding wheels, the present invention provides for dresser structures having capabilities of automatically and simultaneously dressing the entire grinding profile of a cup-shaped wheel while, at the same time, dressing grooves into the sidewalls and annular end of the wheel, if desired. However, the present invention is also very useful for dressing operations which do not involve grooving ofa grinding wheel.

In accordance with the present invention, three separate rotary dresser units are mounted in specific relationships to provide dressing functions which will maintain the profile of a grinding wheel and which may be used to maintain grooves in a grinding wheel. Unlike prior art uses of single point dressers, the present invention utilizes rotary dresser units having shaped heads which are preferably covered with diamond pa. ticles. The shaped heads are rotated at relatively high speeds relative to a rotating grinding wheel, and the rotation of the shaped heads can be reversed to effect changes in surface finish of a grinding wheel. In addition, the invention provides for a number of adjustment features for two of the dresser units so that the same pair of units can be utilized for dressing the sidewalls of grinding wheels having different characteristics of size, pressure angle, and point width. With the adjustment features which are provided by this invention, an identical pair of grinding wheels can be used for a variety of dressing operations, and also, the same pair of dresser units may be used for dressing a grinding wheel for either convex or concave grinding in the case of manufacturing toothed face members.

FIG. 1 is a schematic illustration, in elevation, of a typical machine which may utilize the dresser structures of this invention. The machine which is illustrated is described in greater detail in the above mentioned copending application, but generally, the machine is of a type which can grind curved toothed slots into a face ring of a coupling member. However, it can be appreciated that the dresser structures of this invention can also be used in other grinding machines which utilize cup-shaped, or even disc shaped grinders, and which require periodic dressing of such grinders. The illustrated machine includes a cup-shaped grinding wheel mounted in a housing 102 for rotation and reciprocation within the housing. Means are provided for rotating the grinding wheel during dressing of the wheel and also during actual engagement with a workpiece 104, and any suitable means may be included for oscillating the grinding wheel up and down on its vertical axis of rotation, as viewed in FIG; 1. Detailed descriptions of means for oscillating and rotating the grinding wheel 100 are included in the above-mentioned application, and such means include motor means and control devices for dictating a sequence of movements to the grinding wheel, as may be required for any particular grinding operation. FlG. 1 shows an assembly 106 of dresser structures mounted on the machine so as to be movable from inoperative to operative positions for dressing the grinding wheel 100. The dresser structure assembly 106 may be pivotally pinned at 108 to a portion of the machine housing, and a hydraulic ram may be interconnected between a portion of the machine and the dresser assembly 106 to move the dresser assembly from the inoperative position (which is illustrated) to a dressing position (shown by dashed lines in FIG. 1). Any suitable control means may be provided for actuating the hydraulic ram 110 at periodic intervals to place the dresser assembly 106 in a position to receive the cup-shaped grinding wheel 100. When the dresser assembly is in a dressing position, the cup-shaped grinding wheel, which opens downwardly in the illustrated embodiment, is moved downwardly on its vertical axis of rotation so as to engage separate dresser units of the dresser assembly.

Referring to FIGS. 2 and 3, it can be seen that the dresser assembly 106 includes three separate rotary dresser units which are mounted in positions for dressing the inner and outer sidewalls and the annular end of a cup-shaped grinding wheel. A first rotary dresser unit 112 contacts an inside sidewall portion 113 of the grinding wheel 100, and a second rotary dresser unit 114 contacts and outside sidewall portion 115 of the grinding wheel. As shown in FIG. 3, a third rotary dresser unit 116 is positioned to contact the downwardly depending annular edge of the grinding wheel 100. Thus, the three dresser units may be considered to include a pair of

units

112 and 114 which cooperate to simultaneously dress both inner and outer sidewalls of a cup-shaped grinding wheel together with a third dresser unit 116 which contacts and dresses the annular end of the grinding wheel. Of course, it is to be understood that the orientation of the dresser units and of the grinding wheel may be changed from what is shown in FIG. 1 inasmuch as some grinding machines mount cupshaped grinding wheels on horizontally disposed axes of rotation. Also, it can be appreciated that FIGS. 2 and 3 illustrate the dresser units in positions for actually dressing a grinding wheel, and when a dressing operation is completed, the entire assembly 106 of dresser units is moved outof the way of the grinding wheel (as shown in FIG. 1) so that the grinding wheel can be brought into grinding engagement with the workpiece 104. In a typical operation, grinding is carried on for a period of time before the grinding wheel is withdrawn for periodic dressing, and the frequency of dressing depends largely upon the type of grinding operation which is being carried out and the amount of deterioration of the grinding wheel which may exist for the particular grinding operation.

FIGS. 2 through 4 illustrate the three dresser units of the present invention in a schematic form so as to emphasize basic components and adjustment features which are provided for the entire assembly FIGS. 5 through illustrate the same three types ofdresser units in greater detail and with reference to a specific embodiment.

Referring to FIGS. 2 through 4, each of the three

dresser units

112, 114, and 116 comprises a rotary dresser unit having a shaped head which contacts a cup-shaped grinding wheel for dressing operations. The-shaped head portion of each rotary dresser is preferably surfaced with diamond particles in accordance with known techniques, and typical known constructions provide for a cementing or setting ofa large number of relatively small diamond particles on all surfaces which are intended to engage and dress a grinding wheel. All three of the dresser units are considered rotary dressers in the sense that they include means for rotating the shaped heads while in contact with a grinding wheel to effect a dressing operation. The two

dresser units

112 and 114 which function to dress inner and outer sidewall portions ofa grinding wheel are rotated by a common motor means 118. The third dresser unit 116 is rotated by its own motor means 120 so that it can be controlled separately from the pair of dresser units which dress the sidewalls of a grinding wheel. The three dresser units are rotated at relatively high speeds (for example, at approximately 5000 r.p.m. or 3700 feet per minute) to effect a dressing operation. While the three dressing units are in contact with the grinding wheel 100, the grinding wheel is also rotated. In a rough dressing operation, the grinding wheel may be rotated at a relatively slow rate (for example, 5 rpm.) and in a direction which moves its sidewall surfaces in the same direction as surface movements of the two

dresser units

112 and 114. When it is desired to change the characteristic of dressing of the grinding wheel, the

dresser units

112 and 114 may be reversed in their directions of rotation so that hey are opposing the surface movement of the grinding wh :el 100 between them. Such a change in dressing operation may be desired in a finish dressing process wherein the grindii g wheel is rotated at a much higher rate (for example, at 2000 r.p.m. or 60007000 feet per minute). FIG. 3 shows the movement of the grinding wheel 100 between the

dresser units

112 and 114 in a direction which is the same as the surface movements of the two dresser units. If it is desired to change the dressing characteristic, the grinding wheel is rotated in the same direction as shown in FIG. 3, but the two

dresser units

112 and 114 are reversed in their rotations. Also, dressing characteristics can be changed by providing variable speed motors for the rotary dresser units so that the rotation of the units can be varied over a range ofsurface speeds.

FIGS. 2 through 4 illustrate basic adjustment means which are provided for the dresser units, especially the two

dresser units

112 and 114 which contact inner and outer sidewalls of the cup-shaped grinding wheel 100. As is well-known in this art, it is very important to carefully control the precise shape and size ofa grinding wheel so as to effect a precision cut in a workpiece. To a large extent, the shape of the grinding wheel can be controlled by the shapes of the dresser heads which contact the grinding wheel, but in addition, it is necessary to be able to provide for some modification or adjustment of whatever shape may be imparted to the grinding wheel by a particular set of rotary dressers. This is especially critical with respect to the sidewall portions ofthe grinding wheel since the sidewall portions include almost all of the grinding area which will contact a workpiece, and therefore, the sidewall dresser units of this invention are provided with a number of adjustment features for controlling precise positions of the two

dresser units

112 and 114.

Considering only the two

dresser units

112 and 114. as illus trated in FIGS. 2 and 3, it can be seen that the two units are mounted relative to the grinding wheel, during a dressing operation, so that their axes of rotation 122 and 123, respectively, are parallel to each other and to the axis of rotation 126 of the grinding wheel. In addition, as shown in FIG. 3, the axes of rotation 122 an 124 lie on a line 128 which comprises an extension of a single radius of the grinding wheel. Using these relationships as references, there is an imaginary apex point of the grinding wheel at 130 (see FIG. 2), and this apex reference may serve as a guide for positioning the third dresser unit 16 relative to the end of the cup-shaped grinding wheel. For example, in a typical dressing setup, the third dresser unit 116 is positioned to make contact with the grinding wheel at a level which is just above (0.010 inches, for example) the position of the imaginary apex" so that there will always be some dressing of the very end of the grinding wheel. The various adjustment features which are provided for the dresser units, especially the two

units

112 and 114, are concerned with providing variations in the positions of the two dresser units relative to each other and to the grinding wheel itself.

The adjustment features for the

side dressers

112 and 114 include the following:

a. A first adjustment means for adjusting the spacing between the

axes

122 and 124 of the first and

second dresser units

112 and 114. This adjustment means may comprise means for mounting the dresser unit 112 for sliding movements toward and away from a fixed position of dresser unit 114. Such a mounting arrangement is shown. in FIGS. 2 and 3 wherein the dresser unit 112 is carried by a mounting block 132 which can slide toward and away from the dresser unit 114 on a track or guiding means provided in a separate mounting block 134 which carries the dresser I14. Fastening devices 126, such as bolts, can be used to fix the position of the block 132 once a correct spacing is determined, and elongate slots 138 are provided in the block 134 so that the bolts 136 can be loosened and moved with the movement of the block 132. This adjustment feature provides for a variation in the point width of the lowermost annular end of the cup-shaped grinding wheel which is illustrated.

b. A second adjustment means for simultaneously moving both

dresser units

112 and 114 up or down the sidewalls of the cup-shaped grinding wheel so as to change the height at which a work tooth chamfering surface is formed on each sidewall of the grinding wheel, as related to the annular end of the grinding wheel. Both

dresser units

112 and 114 can be lifted and lowered as a unit by loosening fastening bolts 140 and sliding the mounting block 134 up and down on a track or guiding means 142 associated with a separate mounting block 143 which carries the motor 118. Although not shown clearly in FIG. 2, the shaped heads of the

dresser units

112 and 114 include somewhat irregular configurations which provide a surface on each sidewall of the grinding wheel, which simultaneously grinds a tooth profile and a chamfered top edge on a tooth. This adjustment feature allows the level of chamfering to be changed relative to the end of the grinding wheel.

c. A third adjustment means for simultaneously moving both of the dresser units 112 and 1141 along the radius line 128 so as to adjust the positions of the dressers for various diameters of grinding wheels or to modify the radial position of the annular end of the grinding wheel. This adjustment is provided by sliding a block member 144 back and forth on a mounting casing structure 146. The block member 144 carries all subassembly components of the two

dresser units

112 and 114 and therefore, the two dresser units are simultaneously moved back and forth along the radius line 128 when the fastening bolts 147 are loosened to permit a sliding movement of the block 144 in tracks or guide slots 148 of the mounting casing structure I46. Relatively large adjustments may he provided for this movement so that the dresser structures can be positioned to dress a wide range of diameters of grinding wheels. For example, it is contemplated that the illustrated dresser units may be adjusted to dress grinding wheels which vary in size from approximately 9 inches in diameter to approximately 24 inches in diameter.

d. A fourth adjustment means for simultaneously tilting both of the

dresser units

112 and 114 in the plane which passes through the radius line 128 and both axes of

rotation

122 and 124 of the dresser units. In the adjustment positions as illustrated in FIG. 2 this tilting movement would take place about the imaginary apex point 130, and such movement has the effect of changing the otherwise parallel relationship of the axes of rotation of the two

dresser units

112 and 114 relative to the axis of rotation 126 of the grinding wheel. However, the real purpose in providing this adjustment is one of changing the pressure angle which is formed on the sidewall surfaces of the grinding wheel (the pressure angle surface being the surface on a grinding wheel below the chamfered surface mentioned above). This adjustment constitutes a very fine and critical adjustment for carefully controlling the pressure angle of a finished toothed slot which is formed in a workpiece. The .adjustment is made by loosening fastening bolts 150 so that a mounting block 152 t an slide and rotate relative to the fixed position of an ounting block 154. Curved tracks or guide slots 156 are j rovided to guide the tilting movements of the mounting block 152 and all of the components carried by it (the dresser units .112 and 114 and the motor 118).

. A fifth adjustment means for simultaneously tilting both of the

dresser units

112 and 114 about an axis 158. The axis 158 passes through the axis of rotation 126 of the grinding wheel. Tilting movement of both

dresser units

112 and 114 about the axis 158 provides for a modification of the profile of the sidewalls of the cup-shaped grinding wheel 100, and this modification, although slight, is important for precise control of the tooth profile configuration. In accordance with known theories and techniques, the profile of a grinding wheel is modified to change the bearing surface of a tooth which is formed by contact of the grinding wheel with a workpiece. This ad justment is effected by loosening

fastening bolts

160 and 162 so that the mounting

blocks

132, 134 and 143 can be rotated relative to an extended portion 164 of the mounting block 152. It can be seen that the mounting block 143 is journaled into the portion 164 of block 152 so that rotation takes place about the axis 158.

f. A sixth adustment means for lifting and lowering the level i of the axis 158 so as to change the position of the point about which the above-mentioned fourth and fifth adjustments can take place. This adjustment feature has the effect of changing the level from which the profile adjustment is made on the sidewall surfaces ofa grinding wheel, for example, to make the profile modification symmetrical about a line representing the mean height of a tooth. This adjustment is accomplished by loosening fasteners 168 so that the mounting block 154 can be lifted and lowered on a track 170 relative to the slide block 144. The third dresser unit 116 does not require the same number of critical adjustment features as discussed above for the

sidewall dresser units

112 and 114. Therefore, the third dresser unit 116 may be mounted in a relatively fixed position so as toalways contact the grinding wheel at or near the imaginary apex point 130. However, adjustment is provided for the third dresser unit 116 to precisely set its position relative to the apex" point 130 (or to any other datum line which may be established for the operation of the grinding machine), and an additional adjustment feature may be provided lor automatically lifting the third dresser unit 116 by a sufficient amount to completely remove the grinding edge which is otherwise formed at the annular end of a cup-shaped grinding wheel. Such an adjustment feature may be provided when it is intended to use the grinding wheel in finish grinding operations where no contact is made by the annular ind of the wheel with a previously roughed bottom of a tooth slot.

FIGS. 5 through 13 illustrate details of a specific embodiment for the pair of

dresser units

112 and 114 discussed above. The basic relationships and adjustments which were discussed above with reference to FIGS. 2 through 4 apply to the specific embodiment which will now be discussed, and it is to be understood that this specific embodiment represents only one example of a detailed construction which can be manufactured in accordance with this invention. Other examples of construction, including equivalent variations, will come to mind to those skilled in this art, and it is not intended that the present invention be limited to the specific example shown in FIGS. 5 through 13.

FIGS. 5 and 6 illustrate two different perspective views of the dresser units of this invention, as installed on a machine of the type shown in FIG. 1. Although the following discussion will emphasize the detailed features of the pair of

dressers

112 and 114, it can be seen that the relationship of the third dresser unit 116 is also shown in FIGS. 5 and 6. As discussed above, all three dresser units are carried by a relatively large mounting casing structure 146, and this mounting casing structure functions to properly position all dresser units relative to each other and relative to a grinding wheel carried by the machine. The mounting casing structure 146 is pivotally attached at 108 to a portion of the machine, and a hydraulic ram functions to swing the entire casing structure, and the dresser units mounted thereon, about the pivot 108 so as to place the dresser units into an operative position for dressing a cup-shaped grinding wheel which is moved downwardly into engagement with the rotary dresser heads. FIGS. 5 and 6 illustrate the dresser units in such an operative position, and FIG. 5 clearly shows the upwardly directed dressing heads of the two

dressers

112 and 114 and a horizontally disposed dresser unit 116. The shaped dressing heads contact opposite sidewalls and an annular end wall of the cup-shaped grinding wheel when the grinding wheel is brought down into dressing engagement with the dresser units. However, it is to be un derstood that dressing could be accomplished by moving all three dresser units upwardly into engagement with the grind ing wheel as well.

' FIG. 5 shows the mounting block 132 which carries the rotary dresser 112 for movement towards and away from the second rotary dresser 114. An adjustment device 232 is carried by the mounting block 134 so that precise movements of the dresser 112 can be made relative to the position of the dresser 114. The adjustment means 232 includes a threaded member which can be manually turned to effect sliding move ment of the block 132 relative to the block 134, and this adjustment means will be discussed in greater detail with reference to FIGS. and 10. FIG. 5 also illustrates the relationship of mounting block 134 relative to the separate mounting block 143. The mounting block 134 can be moved vertically relative to the block 143, and this provides for the second adjustment feature discussed above under (b). An electric motor 118 is shown as being mounted on the mounting block 143 for driving a pulley 180. Both of the

dressers

112 and 114 are driven from this motor 118, and the motor is preferably of a reversible type so that the directions of rotation of the dresser heads can be reversed.

FIG. 6 illustrates the mounting block arrangements which provide for the additional adjustment features discussed above, and the various sliding blocks and other members can be picked out by the reference numerals which are related to the discussion of what is shown schematically in FIGS. 2 and 3. Also, FIG. 6 shows a rear end portion 182 of the third dresser unit 116, and it can be seen that the third dresser unit is mounted in the same mounting casing structure 146 which carries the two

side dresser units

112 and 114.

FIGS. 7 and 8 show the assemblies for the two

dresser units

112 and 114 of FIGS. 5 and 6, but the assemblies have been tilted and partially exploded to show detail. The views of FIGS. 7 and 8 are more or less from the bottom of the dresser units, as compared to the positions in FIGS. 5 and 6, and the driving arrangement for the two

dresser units

112 and 114 is

Claims

1. In apparatus for dressing grinding wheels, especially cupshaped grinding wheels, the improved combination comprising: first and second rotary dresser units which function as a pair of dressers for simultaneously dressing inner and outer sidewall portions of a cup-shaped grinding wheel, said first and second rotary dresser units having axes of rotation which are parallel to each other and to the axis of rotation of said cup-shaped grinding wheel when the dressers are in dressing contact with the grinding wheel, mounting means for positioning said first and second rotary dressers into dressing contact with said cup-shaped grinding wheel with the axes of rotation of both of the dressers being on a common radius line taken from the center of rotation of the grinding wheel, adjustment means for adjusting the positions of said first and second dressers relative to each other and to said grinding wheel, and motor means for rotating said rotary dresser units.

2. The combination of claim 1 wherein said adjustment means further comprises (a) a first adjustment means for adjusting the spacing between the axes of rotation of said first and second dressers so as to change the point width of the dressers relative to the grinding wheel, (b) a second adjustment means for simultaneously moving both of said dressers up or down the sidewalls of said cup-shaped grinding wheel so as to change the heights of chamfered surfaces on the sidewall portions of the grinding wheel relative to annular end of the grinding wheel, (c) a third adjustment means for simultaneously moving both of said dressers along said common radius line so as to adjust the positions of the dressers for various diameters of grinding wheels, (d) a fourth adjustment means for simultaneously tilting both of said dressers in a plane which passes through their axes of rotation and through the axis of rotation of said grinding wheel, so as to change the pressure angle contact of said dressers with said grinding wheel, (e) a fifth adjustment means for simultaneously tilting both of said dressers in a plane at right angles to the plane in which said fourth adjustment means is made so as to modify the profile of the inside sidewall of said grinding wheel, and (f) a sixth adjustment means for moving the level at which said fourth and fifth adjustment means take place.

3. The combination of claim 1 wherein each of said first and second dresser units includes a shaped head portion covered with diamonds for making dressing contact with a grinding wheel.

4. The combination of claim 1 wherein said motor means comprises a reversible motor, whereby the rotating contact of said dressers with a grinding wheel can be reversed to obtain different dressing characteristics.

5. The Combination of claim 1 and including a third rotary dresser unit for dressing an annular end of a cup-shaped grinding wheel.

6. The combination of claim 5 wherein said third dresser unit is mounted relative to said first and second dresser units with its axis of rotation parallel to a radius line from the center of said grinding wheel and angularly displaced from said common radius line along which said first and second dresser units are located during dressing operations.

7. The combination of claim 6 wherein said third dresser unit is angularly displaced from said common radius line by 36*.

8. The combination of claim 5 wherein said third dresser unit includes means for moving said dresser unit towards the annular edge of said grinding wheel so as to remove an excess amount of material from the annular edge for certain grinding operations.

9. In apparatus for dressing grinding wheels, especially cup-shaped grinding wheels, the improved combination comprising: first and second rotary dresser units which function as a pair of dressers for simultaneously dressing inner and outer sidewall portions of a cup-shaped grinding wheel, said first and second rotary dresser units having axes of rotation which are parallel to each other and to the axis of rotation of said cup-shaped grinding wheel when the dressers are in dressing contact with the grinding wheel, a third rotary dresser unit which functions to dress an annular end of said grinding wheel, means for moving all three rotary dresser units into and out of dressing engagement with a rotating grinding wheel, motor means for driving all three rotary dresser units.

10. The improved combination of claim 9 and including adjustment means for adjusting the positions of said first and second rotary dressers relative to each other and to said grinding wheel.

11. The improved combination of claim 9 and including means for effecting relative movement between said dresser units and said grinding wheel so as to generate grooves in the sidewalls and the annular end of said grinding.

12. The improved combination of claim 9 wherein said third dresser unit has an axis of rotation which is parallel to a radius of said grinding wheel and angularly displaced from another radius of said grinding wheel along which said first and second dressers are positioned.

13. The improved combination of claim 12 wherein said third dresser unit is angularly displaced from said first and second dresser units by an angular amount which divides a 360* circle into equal segments.

14. The improved combination of claim 9 wherein said adjustment means further comprises (a) a first adjustment means for adjusting the spacing between the axes of rotation of said first and second dressers so as to change the point width of the dressers relative to the grinding wheel, (b) a second adjustment means for simultaneously moving both of said dressers up or down the sidewalls of said cup-shaped grinding wheel so as to change the heights of chamfered surfaces on the sidewall portions of the grinding wheel relative to an annular end of the grinding wheel, (c) a third adjustment means for simultaneously moving both of said dressers along said common radius line so as to adjust the positions of the dressers for various diameters of grinding wheels, (d) a fourth adjustment means for simultaneously tilting both of said dressers in a plane which passes through their axes of rotation and through the axis of rotation of said grinding wheel, so as to change the pressure angle contact of said dressers with said grinding wheel, (e) a fifth adjustment means for simultaneously tilting both of said dressers in a plane at right angles to the plane in which said fourth adjustment means is made so as to modify the profile of the inside wall of said grinding wheel, and (f) a sixth adjustment means for moving the level at which said fourth and fifth adjustment means take place.

15. The combinatioN of claim 9 wherein each of said dresser units includes a shaped head portion covered with diamonds for making dressing contact with a grinding wheel.

16. The combination of claim 9 wherein the motor means for at least said first and second dresser units is a common motor for both units.

17. The combination of claim 16 wherein said motor means is reversible.