Metal deforming – By application of fluent medium – or energy field – With actuated tool engaging work
Reexamination Certificate
2000-06-12
2001-08-28
Jones, David (Department: 3725)
Metal deforming
By application of fluent medium, or energy field
With actuated tool engaging work
C072S062000, C029S421100
Reexamination Certificate
active
06279365
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is related to a cold forging forming method for forming a three-dimensional hollow article without rough edges, and especially to a cold forging forming method using an alloy of low melting point instead of mercury as a filler with plasticity, for saving expensive chilling equipment and providing another effect of easy management of operation; thereby cost of purchasing as well as forming can be effectively reduced, besides, latent public damage of pollution in the processing of forming can be eliminated, and safety of forming can thus be increased.
2. Description of the Prior Art
The inventor of the present invention has obtained a U.S. Pat. No. 5,884,516 “THREE DIMENSIONAL COLD FORGING METHOD FOR SHAPING A HOLLOW ARTICLE AND THE APPARATUS FOR THE METHOD”. Wherein, liquid mercury is used as a freezing medium filled in the space between a die protecting member and the external wall of a seamless die cavity. The liquid mercury can be poured, discharged and recollected at normal temperatures but can have good stiffness after being frozen, thereby, the freezing medium can support the die cavity against forging pressure after being frozen. By the law of conservation of energy, and by the high plasticity of polyurethane, a polyurethane strip placed in a blank to be forged swages the blank when it is pressed to deform and expand by a forging press. In this way, the inner and external walls of the blank is shaped into the shape of a three dimensional seamless die cavity, thus troubles in producing three dimensional artistic articles can be solved.
However, cost of equipment for fast freezing in the markets is much higher than that of heating equipment. And freezing temperature of liquid mercury is −38.5° C., thereby, liquid mercury is preferably to be fast frozen to −40° C. in favor of shaping the cold forged blank, this induces increasing of cost in purchasing equipment. And energy consumption for freezing liquid mercury is much larger than that for the equipment for heating, thereby cost of production can be higher and tends to be a burden. And more, liquid mercury has high specific gravity and is a kind of expensive metal; it is fluid at normal temperatures. When in delivery, it is extremely subjected to generating spattering; this makes inconvenience in management by operators, and tends to create damage to human bodies and public pollution environmentally. Therefore, this forms a very large trouble in the process of forging three-dimensional hollow articles.
SUMMARY OF THE INVENTION
Accordingly, using liquid mercury as a freezing medium can increase cost of production, and can induce quite much trouble in management of operation, and this is the motive of study and development of the present invention. The inventor of the present invention invented the cold forging forming method for forming a three-dimensional hollow article without rough edges based on his specific experience of years in metal processing.
The main object of the present invention is to provide a cold forging method for forming a three-dimensional hollow article without rough edges, wherein, an alloy of low melting point is used as a plastic filler with plasticity, thereby an object of changing or recovery for reusing the filler can be achieved, and cost of forming can be reduced.
To achieve the above stated object, in the present invention, an alloy of low melting point is used as a filler with plasticity in the space between a die protecting member and the external wall of a seamless die cavity instead of mercury as used in the case of the above mentioned prior art. When the alloy of low melting point is in a melting state, it is characterized in the capability of being poured, discharged and recollected but can have good stiffness after being solidified, thereby, a stiff wall of the seamless die cavity can be formed, hence the alloy of low melting point in a solidified state can support the die cavity against forging pressure. The shaped work piece in the die cavity can be released when the solidified alloy is heated to melt, and an inner die for a different die cavity can be substituted for the old one, and an effect of recovery for reusing the filler can be achieved, and cost of forming can be reduced. Moreover, when the alloy of low melting point is in a melting state, stiffness after solidification of the plastic filler is increased by adding and mixing with the material of natural sand, iron sand or steel beads etc. in pursuance of the compression resistance of the forging die required, to suit blanks of higher hardness in forging.
The present invention will be apparent in its object and features after reading the detailed description of the preferred embodiment thereof in reference to the accompanying drawings.
REFERENCES:
patent: 2168641 (1939-08-01), Arbogast
patent: 3383901 (1968-05-01), Stalter
patent: 5813266 (1998-09-01), Ash
patent: 5884516 (1999-03-01), Tseng
Jones David
Pro-Techtor Inter-national Services
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