Metal working – Method of mechanical manufacture – Assembling or joining
Reexamination Certificate
2000-04-18
2002-03-12
Hughes, S. Thomas (Department: 3726)
Metal working
Method of mechanical manufacture
Assembling or joining
C072S325000, C072S326000, C072S379200, C470S204000
Reexamination Certificate
active
06353989
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to improvements in methods of making recesses in at least partially metallic workpieces. More particularly, the invention relates to improvements in methods of making recesses (e.g., in the form of tapped or untapped blind holes or through holes) in workpieces which can be used in torque transmitting. apparatus, for example, in the housings or covers of friction clutches for use in motor vehicles.
As a rule, a recess in a metallic workpiece is obtained by removing material from the workpiece, e.g., by resorting to a drill or to another suitable material removing tool. If the workpiece is to be provided with an internal thread, the treatment with a drill or with another material removing tool (which has been used to form a recess) must be followed by a treatment with a second tool which cuts a thread into the surface surrounding the recess. An internal thread is necessary if the recess is to receive a portion of an externally threaded shank forming part of a screw, bolt, spindle, feed screw, pin, post or the like. For example, it is often necessary to accurately center the workpiece relative to another part by resorting to so-called alignment, locating or centering pins (also called fixing or stead pins), dowel pins, drift pins or plugs, set pins or the like. A centering pin must be installed in a recess with a very high degree of accuracy in order to ensure that the thus coupled and centered parts are secured to each other with a minimum of play, i.e., within an acceptable range of tolerances. Such accuracy can be achieved by resorting to material removing and surface smoothing tools in the form of reamers or the like. All this contributes significantly to the cost of the workpieces, of the combinations of such workpieces with one or more additional workpieces as well as of the machines, apparatus or other devices in which the recessed workpieces are put to use. In addition, it is often difficult to dismantle an apparatus, machine or another device which employs one or more workpieces having one or more recesses which are obtained as a result of removal of metallic material from a blank or from a semifinished component of a friction clutch or the like.
OBJECTS OF THE INVENTION
An object of the invention is to provide a method of making recesses (such as tapped or untapped blind holes or through holes) in metallic workpieces in a simple and inexpensive manner.
Another object of the invention is to provide a method which renders it possible to avoid removal of material from a workpiece in the course of a recess forming or making operation.
A further object of the invention is to provide a method which can be utilized for the making of recesses in workpieces including or constituting blanks or preforms of sheet metal.
An additional object of the invention is to provide a method which renders it possible to make recesses with a high degree of accuracy so that the recesses can accept centering pins, other types of pins, screws, bolts or other male parts with a minimum of play or with no play at all.
Still another object of the invention is to provide a method of making recesses in the end faces of relatively thin workpieces in the form of cylinders, tubes, pipes, sheets or panels in such a way that the diameter or another maximum transverse dimension of a recess at least matches but can exceed the wall thickness of the workpiece.
A further object of the invention is to provide a novel and improved method of treating blanks which can be utilized for the making of covers or housings of friction clutches for use in motor vehicles.
Another object of the invention is to provide a method which can be resorted to for accurately assembling component parts of covers or housings for use in torque transmitting apparatus, such as friction clutches in motor vehicles.
further object of the invention is to provide a method of making recesses which can be practiced by resorting to simple and readily available tools, implements and apparatus.
An additional object of the invention is to provide a torque transmitting apparatus at least one component of which has been treated in accordance with the above outlined method and which can be readily assembled or partially or fully dismantled in a time saving manner.
Another object of the invention is to provide a relatively complex aggregate which can be readily assembled or dismantled because one or more of its components were treated in accordance with the above outlined method.
Still another object of the invention is to provide a torque transmitting apparatus which employs a composite flywheel assembly and a friction clutch utilizing at least one component which has been treated in accordance with the above outlined method.
A further object of the invention is to provide a torque transmitting apparatus at least certain parts of which can be produced, finished, assembled and/or otherwise processed with substantial savings in energy and which is constructed and assembled in such a way that at least a majority of its constituents can be readily separated from each other for inspection, repair or replacement so that each set of parts consisting of the same material can be recycled in an ecologically acceptable manner.
Another object of the invention is to provide a torque transmitting apparatus which can be assembled, inspected, repaired and/or dismantled with greater facility and at a lower cost than heretofore known torque transmitting apparatus.
An additional object of the invention is to provide a torque transmitting apparatus which can be assembled with considerable savings in primary energy and with minimal waste in metallic material.
Still another object of the invention is to provide a method which renders it possible to provide one or more workpieces with tapped or untapped recesses without any contamination of the surrounding area.
A further object of the invention is to provide a method which renders it possible to provide metallic workpieces with recesses free of shavings and/or any other foreign particles necessitating collection and/or expulsion prior to putting the thus treated workpieces to actual use.
Another object of the invention is to provide a method which renders it possible to provide a metallic or partially metallic workpiece with one or more recesses without the need for cooling the workpiece or with minimal cooling.
An additional object of the invention is to provide a method which renders it possible to provide a metallic or at least partially metallic workpiece with one or more recesses without the need for lubrication of tools serving to provide the workpiece with a blind hole, a tapped hole or another recess.
Still another object of the invention is to provide a method which renders it possible to reduce the overall weight of a finished workpiece and which can be practiced in such a way that the tools and/or implements which are used to make one or more recesses can be put to use in, or in conjunction with, the thus treated workpiece.
A further object of the invention is to provide a composite flywheel assembly, particularly for use in torque transmitting apparatus of the type employed in motor vehicles, which is more compact, particularly in the radial direction, than heretofore known flywheel assemblies.
Another object of the invention is to provide a torque transmitting apparatus which is constructed and assembled in such a way that the space heretofore occupied by conventional flywheel assemblies can be put to use to accommodate other components of such apparatus.
An additional object of the invention is to provide a novel and improved cover or housing for connection to the diaphragm spring, damper or dampers, clutch disc, pressure plate and/or other components of a friction clutch for motor vehicles.
SUMMARY OF THE INVENTION
One feature of the present invention resides in the provision of a method of making a recess (e.g., a blind hole or a through hole) in a surface of a workpiece containing a metallic material. The improved method comprises the step of driving into the
Jäckel Johann
Molt Heinz
Compton Eric
Darby & Darby
Hughes S. Thomas
LuK Lamellen und Kupplungsbau GmbH
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