Background of the Invention

This invention relates generally to machines and metho for resurfacing the opposed faces of a disk-shaped workpiec in particular relates to a novel machine and system for ref ing clutch flywheels to achieve a desired pattern.

Motor vehicle clutches normally have a flywheel as a r ing element to be engaged by a friction disk or pressure pl The pressure plate is usually lined with high-friction mater whereas the clutch flywheel itself is usually of metal so a dissipate the heat of friction rapidly and remain sturdy dur operation.

In order to achieve proper clutching action, it is desi that the face of the flywheel, like those of a brake disk, parallel and smooth. However, long or hard use of the clutc tends to roughen or groove the face. Furthermore, rust and contamination may develop with time. Accordingly, refinishi the clutch flywheel surface is often necessary.

Refinishing of brake disks is normally done on a lathe. U.S. Pat. No. 3,456,401 to Rushmuk, for example, shows a br disk resurfacing apparatus which is used as an attachment t lathe. U.S. Pat. No. 3,500,589 to Ellege, which shows a tw resurfacing process, similarly discloses use of a lathe. O resurfacing methods are also disclosed in the art: U.S. Pa No. 3,619,952 to Leming et al., for example, shows the use resilient finishing disks after turning. Additionally, U.S. patents Nos. 4,361,988 to Scharfen and 3,548,549 to Dunn dis the use of opposed cutting members and opposed grinders, re tively. These prior designs all necessitate the use of lar machine tools, in most cases brake lathes, which are quite

SUSSTΪTUTE SKΞET

sive and are furthermore fairly difficult and unwieldy to use well as difficult to assemble and disassemble. Finally, disk resurfaced by prior art methods, which have a concentric patt of resultant machined "lines," in a "phonograph" pattern, ten wear unevenly and display a tendency to glaze.

Clutch flywheels have often been resurfaced on a machine having a rotating abrading element which made full-face conta with the frictional contact area of the flywheel surface. Th resulting complex pattern caused glazing fo the flywheel surf in operation.

This invention is directed to a new machine and method f refinishing clutch flywheels and other disks such as brake di and constitutes a significant improvement over the prior art. The apparatus of the invention is relatively compact. Additi ally, the apparatus is fairly simple to assemble and disasse as it is comprised of relatively simple component parts; thus can be manufactured economically. Flywheels and disks refini by the method of the present invention have a substantially reduced tendency to wear unevenly, and are provided with gre improved surface pattern and parallelism. In addition, fric pad seating ability and parallelism of the flywheel surface, according to testing done by the inventor of the instant inv tion, is substantially improved and there is thus less of a tendency to develop wave patterns that are inherent in metal disks resurfaced by prior art methods which have concentric patterns. Disks resurfaced by the prior art methods display surface pattern that is conducive to galling and glazing; th with the new method, metal disks may be resurfaced far less frequently, and flywheels and disks which otherwise might be thrown away can be salvaged.

summary of the Invention

Accordingly, it is an object of the present invention t provide a method of grinding and resurfacing flywheels and o metal disks which produces a greatly improved surface patter

SUBSTITUTESHEET

thus obviating the need for frequent resurfacing and promoti proper wear.

It is still a further object of the present invention t provide a relatively compact apparatus for grinding disks an flywheels, which apparatus is comprised of relatively simple component parts, is fairly easy to assemble and disassemble, is relatively inexpensive to manufacture.

In one aspect of the present invention, an abrading whe applied to the rotating surface of a flywheel. The flywheel is caused to rotate by means of a drive shaft which supports disk and extends perpendicularly through its axis of rotatio Disc rotation speed may be adjusted by means of a potentiomet

In another aspect of the present invention, the abrading wheel is caused to rotate in an angular direction the same as that of the rotating flywheel. Coarse and fine adjustment mechanisms are included in order to direct the movement of th abrading wheel. In one preferred embodiment of the invention the adjustment mechanisms comprise an interlocking worm gear. The fine adjustment may be driven by a motor with sensor cont based on abrading wheel current draw, for controlling the gri ing pressure and resistance.

The rotating cup-shaped abrading wheel is tilted slightl with respect to the disk surface, so that only one portion of wheel engages the disk at a time.

Other objects, advantages and features of the invention be apparent from the following description of a preferred emb ment, considered along with the accompanying drawings.

Description of the Drawings

Figure 1 is a perspective view of the clutch flywheel an disk grinder of the invention.

SU STSTUTE SHEET

Figure 2 is a partially cut away top plan view of the gr

Figure 3 is a cut away view of the abrading wheel adjust mechanism.

Figure 4 is a side elevation view illustrating the sligh tilt of the abrading wheel with respect to the flywheel.

Figure 5 is a fragmented frontal view of one surface of flywheel or disk, showing the surface pattern achieved by the machine and method of the invention.

Figure 6 is a frontal view of the opposite surface of th flywheel, showing the resurfacing pattern on that side.

Figure 7 is a schematic circuit diagram showing a fine grinding adjustment system preferably incorporated in the invention.

Description of Preferred Embodiment

In Figure 1, the clutch flywheel grinder of the inventio shown generally at 10, is preferably mounted on a level surfa such as a table 11. A flywheel or other grindable disk 12 is shown mounted and held in place by means of a centering devic 14, a washer 16, and a centering bolt 18. The flywheel 12 is caused to rotate about its axis of rotation by means of a dri belt 22. When no longer in operation, the linear position of flywheel may be adjusted by means of a disk adjustment knob 2 operatively connected to a drive shaft 20 (see Figure 2). Wh in operation, the abrasive surface 28 of an abrading wheel 30 caused to contact the disk or flywheel 12, thereby smoothing disk and producing a ground pattern of lines 31 generally in form of curving grooves extending outwardly from the center o the flywheel toward the flywheel perimeter (see Figures 5 and This pattern, in contrast to the pattern of concentric circle produced by the machining methods of the prior art, contribut

SUBSTITUTE SHΞE ^"

to the surprising improvement in results achieved by the pre invention.

Part of the abrading wheel assembly 6 shown generally a the abrading wheel 30 extends toward the flywheel 12 from th motor 38. The abrading wheel is preferably of the cup-shape as shown in the drawings. The wheel is rotated, preferably angular direction the same as that of the disk or flywheel 1 shown by arrows in Figure 1. Superior results are achieved the rotation speed of the disk 12 is at least approximately rpm, and that of the abrading wheel at least about 3450 rp . abrading wheel 30 is rotated by means of the motor 38, and i operatively connected to the abrading wheel assembly shaft 3 The abrading wheel assembly 32 is mounted to the table 11 by means of bolts 44 and 44'. The position of the abrading whe relative to the flywheel 12 may be adjusted by means of a co adjustment knob 40 and a fine adjustment knob 42.

The flywheel grinder is shown in somewhat more detail i Figures 2 and 3. In Figure 2 the mounting assembly is seen partially cut away view. The flywheel 12 is held in place o drive shaft 20 by means of a tapered, generally conical cent device 14, engaged against an opening in the flywheel or dis a bolt 15 and spring 17. The spindle and drive plate assemb is caused to rotate by means of a drive belt 22 driven by th motor 24.

The operational mechanism of the coarse adjustment knob and the fine adjustment knob 42 may be seen in Figure 2 and somewhat more detail in Figure 3. As may be seen, coarse an fine adjustment of the positioning of abrading wheel 30 rela to the disk 12 is effected by means of a worm gear arrangeme shown generally at 46. The worm gear arrangement operates b means of evenly spaced teeth 54 on a worm gear 56 on a coars adjustment shaft 41 by means of an adapter 58, the teeth int locking one-for-one with threads 60 of a worm or screw on a adjustment shaft 52.

SUBSTITUTE SHEET

As can be clearly seen from Figures 2 and 3, the coarse fine adjustments operate as follows: The coarse adjustment k 40 and shaft 41 are rotated to shift the position of the hous 38 via a base 39. The knob 40 and shaft 41 rotate but do not move axially because they are held against axial movement by bracket 43 as shown in Figure 1. Movement of the base 39 is effected by threaded engagement between the threaded shaft 41 internal threads of the worm gear of adapter 58 (if it is fix to the worm gear). Rotation of the shaft therefore causes th worm gear to move axially while remaining non-rotational, and this motion is transferred to the base 39 by free-floating sp sleeves 59 positioned somewhat loosely over the shaft 41 as shown. Rotation of the shaft 41 therefore causes movement of base axially with respect to the shaft 41, in a coarse adjust mode. However, if the fine adjustment knob 42 and shaft 52 worm threads 60 are rotated, the worm gear 56 will rotate ver slowly, advancing along the now stationary threads of the co adjustment shaft 41 and causing the base 39 to advance very slowly, axially with respect to the shaft 41 and the bracket

Figures 4, 5 and 6 illustrate the system and method of invention for achieving a resurface pattern which is highly effective in promoting proper wearing-in of the flywheel dis the friction disk or pad or pressure plate which engages it.

As shown in Figure 4, the abrading wheel 30 is on an ax rotation 64 which is slightly tilted from parallelism with a axis of rotation 66 of the flywheel and its rotating assembl The two axes are at a small angle A from each other, which m about 1°. This assures that only one section of the cup-sha abrading wheel's face will contact the flywheel or disk 12, produce the surface grinding patterns 31 and 31a shown in Fi 5 and 6. In the arrangement shown, generally the lower area the face of the abrading wheel 30 contacts the flywheel, whi the upper area of the face remains spaced from the flywheel.

Figure 5 shows in dashed lines the general position of abrading wheel 30 as it engages the flat face 12a of a flywh

SUBSTITUTE SHEET

or disk 12, as the disk is shown positioned in Figure 4. Th grinding wheel 30, when engaging this unobstructed flywheel 12a, preferably generally straddles the annular frictional a of the face 12a as shown in Figure 5. Only the lower edge o portion of the wheel 30 engages the flywheel face 12a, but because both the wheel 30 and the flywheel 12 are rotating i direction indicated, a surface pattern of curving lines 31 i generated. The curving lines 31 are not truly arcuate, but is of varying radius generally as shown. The lines 31 are g ally transverse to the circumference of the flywheel and to path of engagement of the friction pad or disk or pressure p with the face 12a. Thus, the lines 31 are "generally radial with respect to the general direction in which they sweep ac the contacting friction disk or pad.

Figure 6 shows the position of the abrading wheel 30 on opposite side of the disk 12, for the case wherein a two-sid disk such as a brake disk is to be resurfaced. The wheel 30 engages the frictional surface area 12b. On this side of th disk is a hub 12c, schematically indicated in Figure 6. The prevents the abrading wheel 30 from moving any closer to the center of the disk 12. The resulting resurfaced pattern of 31a is shown generally in Figure 6. Again, the surface line generally radial as engaged by the friction disk (e.g. brake pad), actually comprising a complex curve of varying radius.

Figure 7 shows schmatically a circuit diagram for alter tive type of control for advancing the abrading wheel agains flywheel or disk.

The system diagramatically illustrated in Figure 7 is a ciated with or can replace the fine adjustment of the coarse fine adjustment shown and described above.

in the grinding control system shown in Figure 7, which provides a very fine adjustment of the advancement of the ab ing wheel and thus of the rate of grinding of the material o the face of the flywheel or disk, current draw of the grindi

SUBSTITUTE SHEET

wheel motor 38 is monitored to determine the degree of pressu existing between the abrading wheel 30 and the flywheel or di 12, and thus the rate of grinding.

In the system of Figure 7, 120 volt AC current flows thr the circuit defined by the black wire 70, the gray wire 72 an the motor 38. A starting capacitor 74 is included in the cir cuit. The gray wire 72 passes through a metal loop Hall effe sensor 76 which forms a part of a sensor/controller 78. As indicated, the sensor/controller 78 receives 12 volt current a transformer 80.

The sensor/controller, which may be a Potter and Bru fie current sensor SDAS—017Y251024, is connected to control lead wires 82 and 84, in a circuit with a grinding wheel advanceme motor or lead screw motor 86 as indicated. The lead screw mo 86, although not shown in Figures 1 through 4, can be assumed connected to the fine adjustment knob 42 and shaft 52/56 in Figures 2 and 3. However, it can operate a lead screw advanc mechanism different from the illustrated mechanism if desired

As indicated, the circuit with the lead screw motor or f feed motor 86 is connected to 120 volt AC power, but this is subject to on/off control via the lead wires 82 and 84, under control of the sensor/controller 78.

In order to enable the operator to set and maintain a gi grinding rate or pressure, an adjustment knob 88 on the sen- sor/controller 78 is set at a given amperage by the operator, e.g. three amps or five amps. The Hall effect sensor 76 sen whether the current to the grinder motor 38 is at or below t set level. If the amperage is below the set level on the ad ment knob 88, the sensor/controller will close the circuit w the lead wires 82 and 84 and power the lead screw motor 86 u current reaches the set level. When grinder motor current i the set level, the sensor/controller 28 re-opens the circuit, turning off the lead screw motor 86 and leaving the abrading wheel in the position then set.

SUBSTITUTE SH T

The lead screw motor 36 may have an operating speed of 7 rpm, so that it moves the abrading wheel 30 very slowly i closer contact with the flywheel or disk being surfaced. preferred embodiment of the invention, one revolution of th screw motor 36 (or of the output of an included gear reduct box) preferably causes about .005 inch advancement of the a ing wheel 30.

Thus, by the abrading wheel feed control system shown Figure 7, very fine control of the surfacing/abrading proce made possible. The system also gives the operator a guidel the current level adjustments set from time to time with di ent flywheels or disks, and helps achieve repeatable result

The feed control system, of Figure 7 is applicable to o operations wherein a motor driven tool or implement, whethe grinder, polisher, sander, circular or band saw or other cu surfacing operation, is moved into contact with a workpiece (rotating or still), or vice versa where the workpiece is m toward the implement. The rate and pressure of feed of the workpiece or of the motorized tool can be closely controlle this feed control apparatus.

The above described preferred embodiment is intended t illustrate the principles of the invention, but not to limi scope. Other embodiments and variations to this preferred embodiment will be apparent to those skilled in the art and be made without departing from, the scope of the invention a defined in the following claims.

i CLAIM:

SUBSTITUTE SHEE ^"