Patent Application
20070000360
Not Applicable.
Not Applicable.
The present invention relates to automotive vehicle brake lathes configured for resurfacing brake rotor and drum components, and in particular to automotive vehicle brake lathes utilizing cutting tool holders capable of holding multiple inserts.
One of the main components of a vehicle wheel braking system employing disk brakes are the brake disks, or brake rotors, which provide a solid rotating surface against which the stationary brake friction pads are clamped or compressed to generate a frictional force, slowing the rotational movement of the brake disks or brake rotors and the associated vehicle wheels. The brake disks or brake rotors are subjected to repeated and substantial frictional forces by the brake friction pads, and over time, become worn. Uneven application of braking force, debris, or uneven frictional surfaces on the brake friction pads can result in the formation of grooves, channels, or scratches in the surfaces of the brake disks or brake rotors. Repeated heating and cooling of the brake disk or brake rotor resulting in extreme temperature variations can additionally result in the lateral warping of the brake disk or brake rotor.
A worn or warped brake disk or brake rotor may be resurfaced by cutting or grinding to provide a uniform smooth brake friction pad contact surface, if sufficient brake disk or brake rotor material remains, to provide an adequate braking surface without compromising the structural integrity of the vehicle braking system. However, once a brake disk or brake rotor has been worn below a minimum safe thickness, it is unable to safely dissipate the heat generated by a brake application, and must be replaced.
To provide for a uniform surface, any abnormalities in the brake disk or brake rotor, such as a lateral warping must be detected and removed during the resurfacing procedures. An additional source of lateral warping defects in a brake rotor or brake disk is over tightened attachment bolts or an uneven mounting surface onto which the brake disk or brake rotor is secured in the vehicle wheel assembly. If the brake disk or brake rotor is removed from the vehicle wheel assembly for a resurfacing operation on a fixed or “bench” brake lathe any abnormalities or defects resulting from the mounting of the brake disk or brake rotor to the vehicle wheel assembly may not be accurately identified or corrected during the resurfacing procedure. Accordingly, a variety of brake resurfacing machines or brake lathes have been developed to resurface brake disks and brake rotors while they remain mounted to the vehicle wheel assembly.
Brake resurfacing machines or brake lathes configured to resurface brake disks and brake rotors mounted to a vehicle wheel assembly are commonly referred to as on-car brake lathes. One example of an on-car brake lathe is the OCL-400 brake lathe sold by Hunter Engineering Co. of Bridgeton, Mo. By eliminating the need to remove the brake disk or brake rotor from the vehicle wheel assembly, the overall efficiency of the resurfacing procedure is improved, and the chances for operator induced error are reduced.
Traditionally, on-car and bench brake lathes, such as the BL501/BL505 off-car brake lathe sold by Hunter Engineering Co. of Bridgeton, Mo., utilize motors or drive systems configured for operation at a fixed spindle RPM and feed rate. During rotor cutting or resurfacing, a resonance or vibration, commonly referred to as “chatter”, can develop between the rotor cutting tools and the rotor surface, resulting at best in an uneven resurfacing of the brake rotor, or at worst, in severe damage to the rotor surface or rotor cutting tools themselves. Accordingly, different types of cutting tools of various geometries, materials and coatings are used for “rough” cutting the brake rotor and for “finish” cutting the brake rotor. It is accepted knowledge that a tool with a small nose radius will be less susceptible to chatter. This allows the small radius tool to be useful for removing large amounts of material. The drawback is that the small radius tool is likely to leave a surface finish that is rougher than desired. A tool with a large nose radius is more likely to chatter so it is typically not used to remove large amounts of material. The large radius tool has the advantage of producing a smoother, more desirable surface finish. However, frequent changing of the cutting tools to accommodate different applications is time consuming and can result in misplaced cutting tools. Therefore, there is a need for a tool holder that can accommodate multiple cutting tools so that a single cutting tool will not require frequent removal and replacement.
A cutting tool for a brake lathe for machining automobile brake rotors including an adjustable cutting head. The cutting tool defines a first side and an opposite, second side. The cutting tool also defines a first end and a second end. The first side adjacent the first end defines a mounting surface for removably mounting a first cutting tip. The first side adjacent the second end also defines a mounting surface for removably mounting a second cutting tip. The cutting tool is configured to be mounted in the adjustable head such that the first cutting tip is positioned to machine the automobile brake rotor or the cutting tool may be mounted such that the second cutting tip is positioned to machine the automobile brake rotor.
In an alternate embodiment the tool holder is set up to show that more than one insert is in contact with the workpiece at the same time. This allows the use of a small radius insert to make the preliminary cut for the purposes of removing large amounts of material and the simultaneous use of a large radius insert to provide the desired smooth surface finish.
The foregoing and other aspects of the invention, as well as presently preferred embodiments thereof, will become more apparent from the reading of the following detailed description in connection with the accompanying drawings.
In the accompanying drawings which form part of the specification:
Corresponding reference numerals indicate corresponding parts throughout the several figures of the drawings.
The following detailed description illustrates the invention by way of example and not by way of limitation. The description clearly enables one skilled in the art to make and use the invention, describes several embodiments, adaptations, variations, alternatives, and uses of the invention, including what is presently believed to be the best mode of carrying out the invention.
Referring to
Additionally included on the support structure 14 is an electrical enclosure 24. An operator interface 26 is mounted to the electrical enclosure 24. The operator interface 26, shown in
Operator input controls 34 are additionally included on the operator interface 26. The operator input controls 34 preferably include at least a start button 34A, a stop button 34B, a spindle speed control knob 34C, a compensation button 34D, and a runout test button 34E.
Referring to
Referring now to
Each of the plungers 44 further defines a central opening 52 into which a cutting tool 36 is placed. Each cutting tool 36 is held in position within the central opening 52 by a fastener 54.
In
The cutting tool 36 has a rectilinear body portion 56 and an offset end 58. The offset end 58 has first and second removable cutting tips 60 and 61 that are removably mounted thereto. As shown in
It can be seen that the cutting tools 36 may be inserted in the lathe 10 in one orientation, as shown in
Moreover, the cutting tool 36 can be rotated and exchanged side-to-side such that the circular cutting bit 61 is on top of the cutting tool 36 and only the circular cutting bit 61 comes into contact with the brake rotor 46 to machine the brake rotor 46.
In an alternative embodiment shown in
In yet another embodiment of the present invention of
While the present invention has been described above with respect machining automobile rotors, it will be understood by one of ordinary skill in the art that it further has application to machining brake drums. In this regard and referring to
While the above embodiments have been described with respect to using a combination of circular and triangular cutting bits, one of ordinary skill in the art would readily understand that any combination of bits may be accommodated by the cutting tool or that a single type of bit may be used many times on the cutting tool and the tool rotated as each bit becomes dull.
While the present invention has been described in terms of an on car brake lathe it will be understood by one of ordinary skill in the art that the present invention applies equally to a bench brake lathe as well.
In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results are obtained. As various changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.
