Metal working – Method of mechanical manufacture – Prime mover or fluid pump making
Reexamination Certificate
1999-03-03
2001-03-06
Cuda, Irene (Department: 3726)
Metal working
Method of mechanical manufacture
Prime mover or fluid pump making
C029S558000, C072S379200
Reexamination Certificate
active
06195888
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to hermetic pumps or compressors, particularly reciprocating piston type pumps or compressors.
BACKGROUND OF THE INVENTION
Hermetic compressors typically include a crankshaft having an eccentric portion coupled to a compression mechanism which is driven when the crankshaft rotates. For example, the compression mechanism may comprise a piston slidably disposed in a cylinder, the piston operatively coupled to the eccentric of the rotating crankshaft by a connecting rod, whereby the orbiting motion of the eccentric about the axis of rotation of the crankshaft imparts reciprocating motion to the piston. Due to the dynamic imbalance of the operating compression mechanism, counterweights are often attached to the crankshaft, in some cases directly attached to the eccentric of the crankshaft, to offset the inertial loads generated by the moving members of the compression mechanism and by the eccentric itself.
Previous counterweights for hermetic compressors have been formed directly into the crankshaft or compromise a separate piece assembled thereto, the separate piece being, for example, formed of powdered metal or of stamped sheet metal. Previous stamped sheet metal counterweights, however, have been formed by stamping operations which are unique to the size and weight requirements of a particular counterweight designed to balance only a particular compressor assembly. For example, a product line of several reciprocating piston compressor assemblies, each substantially similar except for the displacement of the compression mechanism, may require unique counterweight tooling to manufacture each of the variety of several counterweights necessary to accommodate all of the compressor assemblies in the product line. A method of providing a variety of stamped sheet metal counterweights, each having different weights but substantially similar in size, whereby a variety of different compressor assembly designs may be balanced, is desirable.
SUMMARY OF THE INVENTION
The present invention provides a hermetic compressor assembly having a housing having disposed therein an electric motor including a stator and a rotor drivingly attached to a crankshaft having an eccentric portion, and a compression mechanism operatively coupled to the crankshaft eccentric portion. A counterweight is attached to the crankshaft and is made of progressively stamped metal stock material having selectively varying widths between first and second side edges thereof. The counterweight has one of a plurality of weights, each individual weight directly corresponding to a different stock material width.
The present invention also provides a method for manufacturing compressors having installed therein counterweights of different weights and having substantially identical axial projection profiles, wherein the counterweights are made by a method which includes providing a progressive stamping die, and planar metal stock material having one of a plurality of different widths between first and second opposite side edges. The stock material is fed through the progressive stamping die in a direction substantially parallel with the first side edge. A counterweight having a weight which variably corresponds to the different stock material widths and having a free edge defined by the first stock material edge is progressively formed from the stock material, and is then separated from the stock material.
The present invention also provides a method of manufacturing a counterweight having the steps of feeding planar stock having side edges and an axial dimension to one or more stamping dies, stamping a segment of the stock into a desired shape, folding the stamped segment in a direction substantially perpendicular to the axial dimension of the stock such that the segment folds back on itself and one of the side edges forms a free end in overlapping arrangement to the segment, and detaching the segment from the stock.
The present invention also provides a method of manufacturing a compressor having installed therein a counterweight, wherein the counterweight is made by a method comprising the steps of: feeding planar stock having side edges and an axial dimension to one or more stamping dies; stamping a segment of the stock into a desired shape; folding the stamped segment in a direction substantially perpendicular to the axial dimension of the stock such that the segment folds back on itself and one of the side edges forms a free end in overlapping arrangement to the segment; and detaching the segment from the stock.
The present invention further provides a method of manufacturing a plurality of sets of compressors having installed therein respective sets of counterweights, each counterweight of one set having a different weight than each counterweight of another set, wherein the counterweights are made by a method which includes the steps of providing a first substantially planar stock material having one of a plurality of widths between side edges into a die, forming a first counterweight having an edge which is defined by one of the side edges of the first stock material, and separating the first counterweight from the first stock material, the separated first counterweight being one of a first set of counterweights. The method further includes the steps of providing a second substantially planar stock material having a different one of a plurality of widths between side edges into the same die, forming a second counterweight having an edge which is defined by one of the side edges of the second stock material, and separating the second counterweight from the second stock material, the separated second counterweight being one of a second set of counterweights.
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Calciolari Leonelo Antonio
Silva José Mario
Baker & Daniels
Cuda Irene
Tecumseh Products Company
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