Technical Field This disclosure concerns a brake resurfacer. In particular, this disclosure describes a resurfacing pad having a layer of abrasive particles that adheres to a brake pad; and methods for resurfacing a rotatable brake member.

Background Brake rotors and drums provide braking surfaces against which brake pads and brake shoes, respectively, frictionally engage to brake a vehicle. Ideally, brake rotors should rotate perpendicularly to the established axis without tolerance.

Brake drums should rotate concentrically to the established axis without tolerance.

In addition, the braking surfaces of brake rotors should be parallel to the caliper brake pad locating surfaces and the face of the hydraulic plunger.

During braking, it is also important that the brake pads and brake shoes"track"perfectly on the braking surfaces of the brake rotors and brake drums, respectively, without lateral movement. Lateral movement or"skating"of the brake pads and brake shoes with respect to the braking surfaces creates undesirable vibration and noise.

Excessive wear during use of the vehicle causes the braking surface of brake rotors and drums to wear unevenly, and generates heat, causing warping in the braking surface. As a result, brake rotors and drums do not rotate perpendicularly and concentrically, respectively, to the established axis. These errors, or tolerances, are known as run out, flatness, parallelism and perpendicularly.

They are the source of many objectionable problems.

In such cases, the braking surface must be resurfaced or, if beyond specified tolerances, replaced. Previously, the braking surface of brake rotors and brake drums has been resurfaced on independent resurfacing devices using either cutting blades, tips, or grinding stones. With independent resurfacing devices, the brake rotor or drum must be dismounted from the vehicle to resurface the braking surface of the brake rotor. Such procedures involve disassembling the rotor or the drum; securing the rotor or drum to an independent resurfacing device such as a turning machine; machining or resurfacing the braking surface; and reassembling the rotor or drum to the vehicle. This procedure is time-consuming, costly and requires great skill and expertise. As a result, many vehicle owners put off necessary brake resurfacing because of the cost and inconvenience of having their vehicle tied up during brake resurfacing.

Moreover, these methods do not entirely achieve a preferred end result. Because the rotor or drum must be disassembled from its original assembly to be placed upon an independent machine, the rotor or drum will not be returned to its identical position upon reassembly. Upon reassembly of the rotors and drums, any accumulated errors or misalignment causes vibration and other objectionable results.

To reduce some of the time required for brake resurfacing and to improve resurfacing results, brake resurfacing devices have been adapted to resurface brake rotors without removing the rotors from the vehicle. Typically, the device is mounted to the wheel hub, wheel shaft, or any other convenient member of the vehicle. The cutting blade, tips, or the grinding stone of the mounted resurfacer is typically supported by the mounted resurfacing device itself. The resurfacing device positions and aligns either the cutting blades, tips, or the grinding stones against the braking surface of the rotor or drum to resurface the braking surface. As a result, brake resurfacing accuracy is dependent upon proper mounting of the resurfacing device. To properly mount the resurfacing device requires careful adjustment. Such adjustment is time consuming and costly.

With both independent and mounted resurfacing devices, the cutter blades, tips, or the grinding stones are carried or supported by the device itself.

Despite careful adjustment, both devices still result in imperfect brake resurfacing.

Because both the independent and mounted resurfacing devices position the cutting blades, tips, or the grinder stones against the rotor or drum braking surface, the

particular idiosyncrasies of the devices are machined into the braking surface of the rotor or drum. These idiosyncrasies, otherwise known as composite errors, include accumulated manufacturing tolerances and wear upon the resurfacing devices over time. These composite errors, which are machined into the braking surface, prevent rotor surfaces from being parallel to the caliper brake pad locating surfaces and the face of the hydraulic plunger and also prevent brake drums from rotating concentrically to the established axis without tolerance.

Some devices addressing these problems are disclosed in U. S. Patent No. 5,816, 901 and U. S. Patent No. 6,139, 413, which patents are herein incorporated by reference. These patents relate to a resurfacing tool that employs all the components of a brake assembly. In use, either the moveable brake pad is removed from the brake assembly and a resurfacing tool is mounted in the brake assembly in place of the brake pad; or, a resurfacing tool is mounted to a new or the partially worn brake pad. The rotor or drum is resurfaced by operating the vehicle. After completing the resurfacing process, the resurfacing tool is removed. This tool eliminates the need to remove the drum or rotor from the vehicle during the resurfacing process. This tool also uses the existing brake assembly to eliminate the problems associated with mounting a resurfacing device, as described above.

Another device that eliminates the need to remove a rotor or drum during resurfacing is disclosed in U. S. Patent 6,213, 260, which patent is herein incorporated by reference. This patent relates to a resurfacing brake pad that also employs all the components of a brake assembly. This device provides a brake pad having abrasive strips across the surface of the pad. In use, the old brake pad is removed from the brake assembly and the resurfacing brake pad is mounted in the brake assembly in place of the old brake pad. The rotor or drum is resurfaced by operating the vehicle. During the resurfacing process, the abrasive strips degrade to fully expose the underlying brake pad upon completion of the resurfacing process.

This tool also eliminated the need to remove the drum or rotor from the vehicle during the resurfacing process and uses the existing brake assembly to eliminate the problems associated with mounting a resurfacing device. In addition, this tool eliminates the need to replace a resurfacing tool after the resurfacing process is complete as the resurfacing brake pad operates to both resurface the rotor or drum, and then function as a normal brake pad.

Summary One aspect of the present invention relates to a resurfacing pad that mounts to a normal brake pad to resurface a braking surface of a brake member.

The resurfacing pad is constructed to automatically permit continued functioning of the normal brake pad after resurfacing is complete.

Another aspect of the present invention relates to a resurfacing pad that employs the components of the braking assembly. The resurfacing pad includes a substrate that adheres to a normal brake pad. The substrate supports abrasive particles for removing braking surface material to resurface a brake member.

Still another aspect of the present invention relates to a resurfacing pad that adheres to a normal brake pad until completion of a resurfacing process.

The resurfacing pad then degrades to expose the normal brake pad and resume normal braking operation.

Yet another aspect of the present invention relates to a method of braking a motor vehicle causing a resurfacing pad to degrade.

Brief Description of the Drawings FIG. 1 is an exploded perspective view of a braking system, utilizing principles of the present disclosure; FIG. 2 is an enlarged, fragmented, side elevational view of the braking system depicted in FIG. 1; FIG. 3 is an enlarged, top plan view of one embodiment of a resurfacing pad used in the braking system depicted in FIG. 1, constructed according to principles of this disclosure; FIG. 4 is an enlarged, bottom plan view of the resurfacing pad depicted in FIG. 3; FIG. 5 is an enlarged, top plan view of another embodiment of a resurfacing pad used in the braking system depicted in FIG. 1, constructed according to principles of this disclosure; FIG. 6 is an enlarged, top plan view of one embodiment of a brake pad including the resurfacing pad depicted in FIG. 3 mounted thereon, according to principles of this disclosure; FIG. 7 is a cross-sectional view of the brake pad embodiment of FIG.

6, taken along line 7-7;

FIG. 8 is an enlarged, top plan view of the brake pad embodiment of FIG. 6 illustrated after use in resurfacing a rotor; FIG. 9 is an enlarged, top plan view of another embodiment of a resurfacing pad having openings; FIG. 10 is an enlarged, top plan view of the resurfacing pad embodiment of FIG. 9 positioned over a brake pad; and FIG. 11 is an enlarged, top plan view of the brake pad of FIG. 10 after the resurfacing pad embodiment has been trimmed.

Detailed Description A. Overview of Brake Pad Construction and Methods In general, this disclosure describes improvements over U. S. Patent No. 5, 816, 901, U. S. Patent No. 6,139, 413 and U. S. Patent 6,213, 260. While the methods and apparatuses described in U. S. Patent Nos. 5,816, 901,6, 139,413 and 6,213, 260 are improvements over the old methods and constructions of the prior art, there can still be further improvements. This disclosure concerns many such improvements.

For example, in the U. S. 5,816, 901 and U. S. 6,139, 413 patents, the resurfacing tool requires the user to disassemble the caliper unit and replace the resurfacing tool with brake pads after the resurfacing is complete. It is desirable to reduce the amount of time and assembly in the process of resurfacing a brake member.

In the U. S. 6,213, 260 patent, the resurfacing brake pads function both as a resurfacing tool, and thereafter as the normal brake pad. Therefore, the step of removing a resurfacing tool is eliminated. The resurfacing brake pad, however, must be purchased as a one-piece construction of brake pad and resurfacing material, requiring distributors to carry more expensive inventories. Similarly, vehicle owners are limited to the type and quality of brake pad manufactured with the resurfacing material to benefit from this resurfacing process.

The methods and constructions described herein simplify resurfacing processes of rotors and drums. When using the constructions as described herein, the vehicle is ready to drive off with no need for further mechanical work. The resurfacing is accomplished within the first few hundred feet of normal driving, without impacting safety of proper braking. The methods and constructions

described herein also accomplish a task of resurfacing the rotor or drum without restriction to the type of replacement brake pad that may be used. The constructions described herein may be used with a variety of existing brake pad configurations.

B. Example Braking System Attention is directed to FIG. 1. In FIG. 1, one example of a braking system utilizing resurfacing pad constructions of the present disclosure is shown at 20. Brake system 20 can be either a disk brake assembly or a drum brake assembly.

In the particular embodiment illustrated in FIG. 1, the brake system 20 is a disk brake assembly 22 used on a motor vehicle. Although the present disclosure is particularly advantageous in the context of vehicle brakes, it will be appreciated that the principles disclosed have application to a variety of other consumer, commercial and industrial machinery where a friction surface of a moveable member is brought into contact with another rotating or stationary surface, including clutches, brake bands, and the like.

Disk brake assembly 22 of FIG. 1 includes a rotatable brake member 24, which is conventionally attached to a wheel. The rotatable brake member 24 may be either a rotor or a drum. In the particular embodiment illustrated in FIG. 1, the rotatable brake member 24 includes a rotor 26 having a braking surface 28. The rotor 26 may be made of cast iron having a hardness of between 100 and 700 Brinell. Preferably the cast iron rotor has a hardness of 180 to 200 Brinell.

Caliper brackets 30,32 are configured for mounting and supporting brake pads 40,42. A caliper housing 34 defines locating surfaces upon which the brake pads 40,42 are supported. A brake line 36 provides power, typically in the form of hydraulic power, to a piston or hydraulic plunger 38 (FIG. 2).

In operation, the disk brake assembly 22 brakes the motor vehicle by slowing rotation of the rotor 26. Specifically, pressure is applied through the brake line 36, which energizes the hydraulic plunger 38. The hydraulic plunger 38 moves the brake pads 40,42 against the braking surface 28 of the rotor 26. The brake pads 40,42 preferably press against the rotor 26 with a force between about 1 lb. and 3500 lbs. of force ; more preferably between 100 and 750 lbs. of force. This frictional engagement of the brake pads 40,42 against the braking surface 28 of the rotor 26 causes the rotor to slow down its rotation, which causes the wheel to slow

its rotation. Preferably the brake pads are engaged with the rotors for a time period of 0.01 to 180 seconds; more preferably between 1 to 60 seconds, inclusively.

The principles of the present disclosure generally relate to a resurfacing pad construction 60 used in a brake assembly. The resurfacing pad construction 60 includes a resurfacing pad 50 attached to an existing brake pad 40, 42. The brake pads 40,42 typically include at least a first braking frictional material 44 mounting on a backing plate 46. The brake pads 40,42 shown in FIG. 2 are configured with resurfacing pads 50 as described in greater detail below. As braking occurs, the resurfacing pad constructions 60 frictionally engage the braking surfaces 28 of the rotor 26 to remove material from the braking surfaces 28. The rotor 26 is rotated about an axis established by the motor vehicle's own spindle bearing. The resurfacing pads constructions 60 are held stationary with respect to the rotor 26. As a result, idiosyncrasies such as those present with independent and mounted resurfacing devices are not machined into the braking surfaces 28 of the rotor 26.

The resurfacing pads 50 of the pad constructions 60 are designed to degrade and wear away after resurfacing the rotatable brake member, such that the first braking frictional material 44 remains to operate in a normal, braking capacity.

It is contemplated that the resurfacing pad construction 60 can also be used for resurfacing components other than those mounted on an assembly of a, vehicle. For example, the resurfacing pad construction 60 may be used to resurface a rotor mounted on a lathe having a structure to accommodate the resurfacing pad construction.

C. Preferred Resurfacing Pad Embodiments Attention is now directed to FIGS. 3 and 4. In FIGS. 3 and 4, one preferred resurfacing pad embodiment is illustrated at 50. The resurfacing pad 50 may typically be used in the brake system 20, described above.

The resurfacing pad 50 preferably includes a substrate material 54, a layer of abrasive grains or particles 56 bonded to the substrate material 54 by a resin 62, and an adhesive layer 52 (shown also in FIG. 7). A removable cover or liner 64 is preferably positioned over the adhesive layer 52.

The substrate material 54 of the resurfacing pad 50 functions as a base to support the layer of abrasive particles 56 and the adhesive layer 52.

Preferably the substrate material comprises a material that has structural integrity

sufficient to support the resurfacing process and will degrade at an appropriate time when resurfacing has been achieved. Usually, in the preferred embodiment, degradation is a function of time and temperature level. Examples of useful materials for substrate material 54 include, for example, natural cloth, woven synthetic cloth, non-woven webs, foil, paper, cellulose, rubber foam, fibers, vulcanized fiber, fiberglass, thermoplastic materials, paper-like polymer films, or any combination thereof.

In the example shown in the figures, the substrate material 54 includes a first surface 70 and a second surface 72 opposite the first surface. The substrate material illustrated is shaped to generally correspond to the existing brake pad shape. Shapes other than that which correspond to the existing brake pads and shoes may also be used. For example, the substrate may be of a shape that covers only a portion of the brake pad or shoe. In the alternative, the substrate material may partially overlap or extend beyond the brake pad or shoe.

In the particular embodiment shown if Figures 3 and 7, the resin 62 is applied to the first surface 70 of the substrate material 54 to bond the layer of abrasive particles 56 to the first surface 70. Preferably the resin 62 comprises a material that has sufficient strength to bond and maintain the abrasive particles 56 on the substrate material 54 to accomplish resurfacing. In one embodiment, the resin penetrates the substrate material and provides a resin/substrate combination having a Rockwell"B"hardness of at least 77.

The resin 62 also preferably will degrade at a time when resurfacing has been completed. Usually, in the preferred embodiment, degradation is a function of time and temperature level. Examples of useful materials for resin 62 include, for example, acrylic resins, silicone resins, rubber resins, vinyl resins, organopolysiloxane resins, phenolic resins, urethane resins, acrylated urethane resins, epoxy resins, acrylated epoxy resins, ethylenically unsaturated resins, urea- formaldehyde resins, isocyanurate resins, acrylated bismaleimide resins, fluorine- modified epoxy resins, resins containing polypropylene, polycarbonate, polyvinylidene chloride, polytetrafluorethylene, polyethylenerphthalate or polyamide, and combinations thereof.

In the preferred embodiment, the layer of abrasive particles 56 bonded to the substrate material 54 by the resin 62 covers the first surface 70 of the

substrate material 54. In particular, the layer of abrasive particles 56 covers at least 25%, typically at least 60% of the first surface of the substrate material 54.

In the embodiment shown, the adhesive layer 52 is located on the second surface 72 of the substrate material 54. Preferably, the adhesive layer 52 is of a material that has sufficient strength to bond the resurfacing pad 50 to the first braking frictional material 44 of the brake pad 40,42. More preferably, the adhesive layer 52 is a Pressure Sensitive Adhesive (PSA) that possesses adhesive characteristics when pressure is applied. In particular, the adhesive layer has a tensile strength between 1 and 100 lbs of force, preferably between 5 and 30 lbs of tensile force. By providing an adhesive construction, the resurfacing pad 50 is conveniently and easily secured to the brake pads 40,42 and eliminates the need for further mechanical work after resurfacing is completed (i. e. removing a resurfacing tool or device).

The adhesive layer 52 also preferably will degrade at a time when resurfacing has been completed. More preferably, the adhesive layer is of a material that has sufficient shear strength to bond the resurfacing pad to the brake pad to accomplish a resurfacing time duration of at least. 01 second to 180 seconds, preferably 1 seconds to 60 seconds.

Usually, in the preferred embodiment, degradation is a function of time and temperature level. Examples of useful materials for the adhesive layer 52 include, for example, temperature-reactive polyesters, polyurethanes, rubber, nitrile rubber, polythene, or polychloroprene rubber. Other material such as organopolysiloxanes may also be used. The adhesive layer 52 is preferably applied to a majority of the second surface 72 of the substrate material 54 to ensure the resurfacing pad 50 properly secures to the brake pad.

In the preferred embodiment, each of the adhesive layer 52, the substrate material 54 and the resin 62 are temperature sensitive and break down or degrade between about 100 degrees F to 1200 degrees F. By"degrade", it is meant that the components (i. e. the adhesive 52, the substrate material 54, and the resin 62) will be eroded (or breakdown) to a point where less than 5%, typically, less than 1 % of the original abrasive particles of the layer of abrasive particles 56 remains (see, for example, FIG. 8). Preferably the components will degrade between 100 and 800 degrees F. More preferably, the components will begin to degrade at about 200 degrees F. The components 52,54, and 62 are configured such that the temperature

degradation begins only after allowing sufficient time for completion of the resurfacing of the braking surface.

The removable liner 64 is positioned on the adhesive layer 52 of the resurfacing pad 50. The removable liner 64 may include any type of liner or cover commonly known to those in the industry for protecting an adhesive layer. In use, the liner 64 is removed to expose the adhesive layer 52 so that the resurfacing pad 50 may be secured to the brake pad 40,42. Preferably the liner 64 is a peel-type liner 65 that is removed by grasping the liner 65 at an edge 66 and peeling the liner 65 back to remove the liner from the adhesive layer 52 of the resurfacing pad 50, thereby exposing the adhesive layer 52.

Referring now to FIGS. 6 and 7, the first braking frictional material 44 to which the resurfacing pad 50 is adhered is a material suitable for operating during normal, braking operations. As such, the first braking frictional material 44 has a coefficient of friction that is sufficient to cause frictional engagement and slowing of a rotor 26, but without removing material from the braking surface 28 of the rotor 26. Typically, the first braking frictional material 44 will have a Rockwell "B"hardness of typically about 64-84. The first frictional material 44 may be made from material of a conventional nature. One suitable material could be TP1353M manufactured by Thiokol. The first frictional material 44 will be a material that will permit normal, braking operation of at least 10,000 miles, typically 30,000 miles, before requiring a change of a brake pad.

The resurfacing pad 50 is configured to secure to the brake pads 40, 42 of the brake system 20 such that the layer of abrasive particles 56 can be moved into and out of engagement with the braking surface 28 of the rotor 26. In other words, the resurfacing pad 50 is oriented between the first frictional material 44 and the braking surface 28 of the rotor 26, such that the layer of abrasive particles 56 will engage the rotor 26 before the first frictional material 44 of the brake pad 40,42 engages the rotor 26. This means that after degradation of the resurfacing pad 50, the first braking frictional material 44 will be exposed.

Preferably, the layer of abrasive particles 56 will have a higher coefficient of friction than the plane of braking frictional material 44. The layer of abrasive particles 56 will be constructed and arranged to remove material from the braking surface 28, when the resurfacing pad 50 is in frictional engagement with the rotor 26. The layer of abrasive particles 56 will have a grade sufficient to produce a

surface condition on the braking surface 28 of about 100-1,000 microinches, when measured laterally across the surface of the rotor 26. In preferred systems, the layer of abrasive particles 56 will have a grade sufficient to produce a surface finish on the rotor 26 of about 200-850 microinches when measured with a profilometer laterally across the surface of the rotor 26; and about 30-150 microinches when measured radially within a particular groove of the rotor 26.

Suitable grades include between 12-1, 000, preferably 24-120 grade, as defined by ANSI standards. The abrasive particles may include, for example, cutting teeth, tines, or other abrasive material for removing braking surface material to resurface a brake member. In particular, the particles may include, for example, high-speed steels, carbides, ceramics, cobalt, zirconium, alumina zirconia, cubic boron nitride, diamond, and any combination thereof, and any other abrasive mineral suitable for machining cast iron braking surfaces. Preferably, the abrasive particles 56 will have a Rockwell"C"hardness of about 60-90, more preferably about 68 or higher.

As described above, components of the resurfacing pad 50 are of a nature and quality to degrade at a temperature between about 100 degrees F and 1200 degrees F. Preferably this degradation begins after 100-500 feet of engagement, or, after 3 to 150 revolutions, typically, at least 15 revolutions of a rotor having a 12-inch diameter. More preferably degradation begins after 40 revolutions of a 12-inch diameter rotor, while the rotor is rotating at approximately 100 to 650 revolutions per minute. Most preferably, degradation begins after 40 revolutions of a 12-inch diameter rotor while the rotor is rotating at about 300-350 revolutions per minute.

Referring now to FIG. 5, one alternative embodiment of a resurfacing pad 50'is illustrated having a layer of abrasive particles 56'with at least one, and more preferably, a plurality (that is, more than one) of abrasive strips or bands 80.

Preferably, there will be no more than 25 bands, typically about 3-20 bands, in some cases, about 5-15 bands 80. Each of the abrasive bands 80 may be separated from an adjacent band by a non-abrasive section or exposed region 82 of the substrate material 54. In the particular embodiment illustrated in FIG. 5, there are 14 abrasive bands 80. While a variety of embodiments are contemplated herein, in the embodiment illustrated in FIG. 5, each of the abrasive bands 80 has about an equal width, ranging from 1/16 inch to 1 inch. In certain, typical arrangements, each of

the abrasive bands 80 will have a width of about 1/8 inch to 1/2 inch, representing 25% to 60% of the resurfacing pad surface.

In preferred embodiments, each of the non-abrasive sections or regions 82 of the exposed substrate material 54 will have about an equal width.

Preferably, each of the regions 82 will have a width of 1/16 to 1 inch, typically about 1/8 inch to 1/2 inch. Although in the FIG. 5 embodiment, the width of the abrasive bands 80 is equal to the width of the regions 82, in other embodiments, they can be of unequal and varying widths.

Preferably, the abrasive bands 80 will be arranged relative to a longitudinal axis 58 to help expedite the removal of degraded material and abrasive particles 56. In preferred arrangements, the abrasive bands 80 will be angled relative to the longitudinal axis 58. Preferably, the angle between each of the abrasive bands 80 and the longitudinal axis 58 will be at least 15°, no greater than about 75°, and typically about 30°-60°. Because the abrasive bands 80 are angled relative to the longitudinal axis 58 in this alternative embodiment 50', the exposed regions 82 create channels to help direct and remove the degraded material and particles from the resurfacing operation. The angle of the regions 82 relative to the longitudinal axis 58 will typically be the same angle as the angle of the abrasive bands 80 relative to the longitudinal axis 58. Typically, this will be at least 15°, no greater than about 75°, and preferably about 30°-60°.

Referring now to FIG. 9, another embodiment of a preferred resurfacing pad 150 is illustrated. The resurfacing pad 150 includes similar components and materials as the embodiment previously described. For example, the resurfacing pad 150 includes a substrate material 154 having a first surface 170 and an opposite second surface 172, a layer of abrasive grains 156 bonded to the first surface 170 of the substrate material 154 by a resin 162, and an adhesive layer 152 applied to the second surface 172 of the substrate material. In accord with the principles disclosed, a cover (not shown) may be positioned over the adhesive layer 152. It is to be understood that each of the components, i. e. the substrate material, the layer of abrasive grains, the resin, the adhesive layer, and the cover may include the materials, structures, and characteristics as earlier disclosed.

In the illustrated embodiment of FIG. 9, the resurfacing pad 150 includes at least one open region, preferably a plurality of open regions 188. The open regions can be formed by punching out portions the resurfacing pad 150.

Other methods of providing open regions, such as providing pre-molded open regions in the substrate material, are contemplated. The open regions may be holes, slots, or any other shaped region defining an open area. Additionally, the open regions may be randomly oriented or non-randomly oriented. In the one shown, the open regions are non-randomly oriented.

The first surface 170 of the resurfacing pad 150 has a total surface area defined by a perimeter 184. The perimeter 184 of the illustrated embodiment is defined by a portion of resurfacing pad 182 that surrounds the configuration of open regions 188. In the preferred embodiment, the open regions comprise 1% to 90 % of the total surface area, more preferably about 25% to 60% of the total surface area.

As shown in FIG. 10, the perimeter 184 of the resurfacing pad 150 is preferably larger than an outer perimeter 186 of the braking frictional material 44 of the brake pad 40,42. More preferably, at least a portion 180 of at least one open region 188 extends beyond the perimeter 186 of the resurfacing pad 150.

Referring now to FIGS. 10 and 11, the resurfacing pad 150 is configured to secure to the brake pad 40,42 of a brake system. In use, the cover (not shown but analagous to the cover 64 of FIG. 4) of the resurfacing pad 150 is removed to expose the adhesive layer 152, and the pad 150 is secured to the brake pad 40,42. The user may then cut or trim the resurfacing pad 150 along the outer perimeter 186 of the braking frictional material 44. Because of the configuration of the open regions 188, areas or strips of abrasive material 178 remain when the portion of resurfacing pad 182 that surrounds the configuration of open regions 188 is removed.

In both resurfacing pad embodiments 50'and 150, shown in FIG. 5 and FIG. 9, the band or open region configurations define a corrugated pattern that promotes disintegration of the resurfacing pad 50', 150. In particular, the abrasive strips 80 and the region of substrate bands 82 of the resurfacing pad 50'in FIG. 5 define a corrugated pattern having raised and lower portions, respectively. The strips of abrasive material 178 and the open regions 188 of the resurfacing pad 150 in FIG. 9 define a corrugated pattern having raised and lower portions. The raised and lower portions of either embodiment may include peaks and valley or ridges and groove, and include a number of cross-sectional configurations of either the raised and lower portions. The corrugated pattern typically causes the resurfacing pad 50', 150 to degrade after a braking interval of between 0.1 and 180 seconds; preferably,

the corrugated pattern is designed to cause degradation of the resurfacing pad 50', 150 between about 15 and 60 seconds.

FIG. 11 illustrates a resurfacing pad construction 160 having a trimmed resurfacing pad 151. The trimmed resurfacing pad 151 includes areas of abrasive material 178 and areas of exposed braking frictional material 144 defined by the open regions 188. The abrasive material 178 illustrated define independent abrasive strips adjacent one another and separated by the open regions 188. Other abrasive and open region configurations are contemplated. In the preferred embodiment, the open regions 188 extend to the outer perimeter 186 of the braking frictional material. Therein, the corrugated pattern as described above exists at the perimeter 186 of the braking frictional material.

D. Preferred Methods of Operation In operation, the resurfacing pad construction 60,160 can be used to both resurface the braking surface 28 of the rotor 26 and operate as a normal brake pad, as described below.

Typically, it is suggested that after approximately 30,000 miles of operation, the braking surface 28 of the rotor 26 be resurfaced. To accomplish this, the resurfacing pad 50 described herein may be used. To resurface the braking surface 28 of the rotor 26, the tire of the vehicle is removed. Next, the caliper housing 34 is disassembled and the presently existing brake pads are removed.

Resurfacing pads 50 are adhered to new or the partially worn brake pads 40,42 by removing the liner 64 of the resurfacing pad 50 and pressing the layer of adhesive 52 onto the braking frictional material 44 of the pads. These resurfacing pad constructions 60 (i. e. the brake pads 40,42 with adhered resurfacing pads 50) are installed into the caliper housing 34 and the caliper housing 34 is again reassembled to the wheel. The tire is remounted to the wheel.

In the alternative, when the resurfacing pad embodiment 150 of FIG.

9 is used, the resurfacing pad 150 is trimmed to remove the excess surface area of the resurfacing pad 150 that extends over the outer perimeter 186 of the braking frictional material 44. These resurfacing pad constructions 160 are then installed into the caliper housing 34, and the caliper housing 34 is again reassembled to the wheel. The tire is remounted to the wheel.

The remainder of this method of operation disclosure is described with reference to the first embodiment of the resurfacing pad 50 for purpose of brevity only. It is to be understood that the principles of the disclosed method of operation also apply to the other embodiments herein disclosed.

Next, the motor vehicle is driven, or run with the rotor/wheel raised, and the resurfacing pad constructions 60 are hydraulically pressed against the rotating rotor 26. In the alternative, the resurfacing pad constructions 60 may be pressed mechanically, electrically, or in combination, against the rotating rotor 26.

While the resurfacing pad constructions 60 are pressed against the rotor 26, the layer of abrasive particles 56 frictionally engages the braking surface 28. The engagement is sufficient to remove material from the braking surface 28. This step of removing material from the rotor 26 is continued, until the adhesive layer 52, the substrate material 54 and the resin 62 have degraded. Typically, this will occur when the temperature is between about 100 to 1200 degrees F or after about 100-500 feet of engagement at driving speeds above 30 mph. Degradation may also be characterized as a function of brake force, time, and revolutionary speed of the rotor.

In the preferred method, the pad is press against the rotor with a force of 1 to 3500 lbs of force for a time period of 0.01 to 180 second with the rotor rotating at 10 to 1200 rpm. More preferably, the pad is press against the rotor with a force of 100- 750 lbs of force for a time period of 1 to 60 second with the rotor rotating at 100 to 850 rpm. As the components of the resurfacing pad 50 degrade, the abrasive particles drop off and the first braking frictional material 44 of the braking pad 40, 42 is exposed (see FIG. 8).

The step of removing material from the rotor 26 by contact with the layer of abrasive particles 56 not only resurfaces the braking surface 28, but also functions to slow rotation of the rotor 26, to act in a normal, braking capacity. As shown in FIG. 8, after the resurfacing pad 50 degrades, the first braking frictional material 44 is exposed to make frictional contact with the rotor 26 when the brake pad is pressed against the braking surface 28 of the rotor 26. That is, after the resurfacing pad 50 degrades, the brake pads 40,42 function to slow the rotation of the rotor 26 by frictional engagement between the first frictional material 44 and the braking surface 28, without the first frictional material 44 resurfacing the braking surface 28. The brake pads 40,42 with the first frictional material 44 in frictional

engagement with the braking surface 28 will serve to brake the motor vehicle for at least another 10,000 miles, typically another 30,000 miles.

Eventually, the braking surface 28 of the rotor 26 will again need resurfacing. Typically, this will be when the first frictional material 44 has worn to about 1/16 inch from the backing plate 46. Usually, this is after another 10,000- 30,000 miles. The brake pads 40,42 will be removed, and second, new resurfacing pad constructions 60 will replace them. The second, new resurfacing pad constructions 60 will operate to resurface the braking surface 28 of the rotor 26, and then act as normal, typical brake pads. It can be appreciated that with each new set of resurfacing pad constructions 60, there is independent resurfacing advantages, to reestablish the brake pad to rotor 26 frictional characteristics.

While this disclosure has been described with reference to example embodiments, those skilled in the art will recognize that there are many embodiments utilizing the principles described herein.