US3731727A — Pressure intensifying apparatus for a die casting…

Claim 1

Independent Claim 424 words

Pressure intensifying apparatus for a die casting machine comprising: A mold having relatively separable dies facing each other and defining a mold cavity therebetween for receiving molten metal for making a cast product; a sleeve member having one end thereof connected to said mold for feeding an amount of molten metal into said cavity; a first piston-cylinder assembly having a first cylinder slidably receiving a first piston, another piston slidably disposed in said sleeve for forcing molten metal therefrom and into said mold cavity, and a pusher rod having one end connected to the first piston and extending from one end of the first cylinder and its other end connected to said another piston in said sleeve; a second piston-cylinder assembly having a second piston and a second cylinder slidably receiving said second piston, said second piston being formed with a first land portion and a second land portion of greater diameter than the first land portion and said second cylinder being provided with a first portion substantially equal in diameter to said first land portion being slidably disposed therein and a second portion substantially equal in diameter to said second land portion being slidably disposed therein and a chamber in said first portion of said second cylinder on one side of said first land portion being open to said first cylinder on the first piston side thereof so as to enable a fluid pressure to be transmitted from said chamber of said second cylinder onto a functional surface of said first piston; means for feeding a working fluid into first cylinder on the first piston side thereof comprising a spool-like check valve member positioned in said working fluid to allow said working fluid to flow into said first cylinder to move said first piston so as to feed molten metal into the mold cavity, said check valve including axially opposed end surfaces having different pressure-receiving surface areas so that the check valve shuts off the feeding of working fluid into said first piston side of said first cylinder in response to a sudden increase in pressure of the working fluid therein which occurs when the movement of said first piston has been stopped by the filling of said mold cavity with molten metal; and, means for applying a regulated fluid pressure on the functional surfaces of said second land portion of said second piston to remove a desired intensified pressure from the second piston when said spool-like check valve shuts off working fluid flowing into the first piston side of said first cylinder.

Claim 2

Dependent Claim 424 words

Pressure intensifying apparatus for a die casting machine comprising: A mold having relatively separable dies facing each other and defining a mold cavity therebetween for receiving molten metal for making a cast product; a sleeve member having one end thereof connected to said mold for feeding an amount of molten metal into said cavity; a first piston-cylinder assembly having a first cylinder slidably receiving a first piston, another piston slidably disposed in said sleeve for forcing molten metal therefrom and into said mold cavity, and a pusher rod having one end connected to the first piston and extending from one end of the first cylinder and its other end connected to said another piston in said sleeve; a second piston-cylinder assembly having a second piston and a second cylinder slidably receiving said second piston, said second piston being formed with a first land portion and a second land portion of greater diameter than the first land portion and said second cylinder being provided with a first portion substantially equal in diameter to said first land portion being slidably disposed therein and a second portion substantially equal in diameter to said second land portion being slidably disposed therein and a chamber in said first portion of said second cylinder on one side of said first land portion being open to said first cylinder on the first piston side thereof so as to enable a fluid pressure to be transmitted from said chamber of said second cylinder onto a functional surface of said first piston; means for feeding a working fluid into first cylinder on the first piston side thereof comprising a spool-like check valve member positioned in said working fluid to allow said working fluid to flow into said first cylinder to move said first piston so as to feed molten metal into the mold cavity, said check valve including axially opposed end surfaces having different pressure-receiving surface areas so that the check valve shuts off the feeding of working fluid into said first piston side of said first cylinder in response to a sudden increase in pressure of the working fluid therein which occurs when the movement of said first piston has been stopped by the filling of said mold cavity with molten metal; and, means for applying a regulated fluid pressure on the functional surfaces of said second land portion of said second piston to remove a desired intensified pressure from the second piston when said spool-like check valve shuts off working fluid flowing into the first piston side of said first cylinder.

Claim 3

Dependent Claim 315 words

Pressure intensifying apparatus for a die casting machine according to claim 1, wherein: said second piston of second piston-cylinder assembly is provided with an axially extending through opening for flowing a working fluid therethrough and a bore provided at an intermediate position along the longitudinal axis of the opening, said bore having a larger internal diameter than that of the opening; and, said spool-like check valve includes a tubular portion slidably located in said through opening having an open end facing towards the functional surface of said first piston, a closed bottom opposite said open end, and at least one radial opening through which the working fluid can flow, a stem member extending from the bottom of said tubular portion longitudinally through said through opening and end wall of second cylinder of said second piston-cylinder assembly, and a piston mounted on the end of said stem being slidably received in an additional cylinder mounted on said end wall of said second piston-cylinder assembly, said spool-like check valve being capable of movement along said through opening by a defined stroke so that said radial opening of the tubular portion thereof is always exposed in said bore over the entire stroke of said check valve, one of the axially opposite surfaces of said bottom of the tubular portion having a larger pressure-receiving surface area than the other surface by an amount equal to the cross-section of said stem so that a pressure difference resulting therefrom causes said check valve to close said through opening in a direction depending upon the pressure difference when a static fluid pressure is developed on the bottom, and said piston being mounted on the end of said stem causing said bottom of said tubular portion to move away from its closed portion to open said through opening when a working fluid is supplied onto the functional surface thereof in said additional cylinder.

Claim 4

Dependent Claim 65 words

Pressure intensifying apparatus for a die casting machine according to claim 1, further compriSing: a spring-biased fluid back pressure control valve connected in series with a passage for exhausting fluid from a chamber defined by a stepped portion of said second piston between said land portions and said second cylinder so that a predetermined intensified fluid pressure can be provided by said second piston-cylinder assembly.

Claim 5

Dependent Claim 88 words

Pressure intensifying apparatus for a die casting machine according to claim 2, further comprising: a pressure-responsive valve connected with said second cylinder and said additional cylinder and being responsive to a sudden increase in pressure of the working fluid in a chamber in front of said second piston so that a working fluid filling a chamber in front of said piston in said additional cylinder may be exhausted from the additional cylinder to allow movement of the piston therein to close said through opening in said second piston.

Claim 6

Dependent Claim 75 words

Pressure intensifying apparatus for a die casting machine according to claim 1, wherein: said first cylinder of said first piston-cylinder assembly has its one open end directly connected to an open end of said second cylinder of said second piston-cylinder assembly, and the open end of said first cylinder is provided with a portion having a diameter substantially equal to that of said first land portion of the second piston for slidably receiving the same.

Claim 7

Dependent Claim 215 words

Pressure intensifying apparatus for a die casting machine according to claim 1, wherein said spool-like check valve member comprises: a cylinder having first, second, third and fourth chambers arranged in tandem therein, the second chamber having an opening with a valve seat for fluidly connecting the second chamber with the third chamber therethrough, and first and second pistons connected to each other through a piston rod, a part of said first piston being slidably received in said first chamber, said first piston being also provided with opposing first and second fluid function surfaces, the second surface having a smaller area that the first surface by an amount substantially equal to the cross-section area of said piston rod and a shape suitable for seating on said valve seat of the second chamber to shut off said opening against fluid flow therethrough; and, said first and second chambers are communicated with a chamber in front of said first piston of said first piston-cylinder assembly, said third chamber is connected to a pressurized fluid supply, and said fourth chamber may be connected to the fluid supply when required for causing said first piston of said check valve to open said valve seat and is released when a pressurized fluid is supplied from the supply to said third chamber.

Claim 8

Dependent Claim 90 words

Pressure intensifying apparatus for a die casting machine according to claim 1, wherein: said second piston of said piston-cylinder assembly is of solid construction, said spool-like check valve member is located outside of said second piston, and a pressure control valve is positioned in an upward stream of the working fluid that flows into a chamber of the second cylinder in front of said second piston to thereby generate a desirable intensified pressure from said second piston-cylinder assembly in response to the pressure of the working fluid in said chamber.

Claim 9

Dependent Claim 44 words

Pressure intensifying apparatus for a die casting machine according to claim 1, wherein: said first and second piston-cylinder assemblies are spaced apart and are connected through conduit means for transferring an intensified fluid pressure from the second piston-cylinder assembly to the first piston-cylinder assembly.

Claim 10

Dependent Claim 189 words

Pressure intensifying apparatus for a die casting machine comprising: a mold having relatively separable dies facing each other and defining a mold cavity therebetween for receiving molten metal for making a cast product; a sleeve member having one end thereof connected to said mold for feeding an amount of molten metal into said cavity; first piston transfer means having a part thereof slidably disposed in said sleeve for feeding said molten metal therefrom and into said cavity; second piston transfer means for supplying fluid under pressure to said first piston transfer means for moving the same in one direction; a spool-like check valve member in said second piston transfer means for selectively permitting flow therethrough and preventing fluid flow therethrough; and, fluid flow control means for positioning said check valve to permit fluid flow therethrough to operate said first piston transfer means and upon filling said mold cavity being responsive for positioning said check valve to prevent further flow through said second piston transfer means, and further for subsequently operating said second piston transfer means to intensify the pressure of said fluid acting upon said first piston transfer means.

Claim 11

Dependent Claim 189 words

Pressure intensifying apparatus for a die casting machine comprising: a mold having relatively separable dies facing each other and defining a mold cavity therebetween for receiving molten metal for making a cast product; a sleeve member having one end thereof connected to said mold for feeding an amount of molten metal into said cavity; first piston transfer means having a part thereof slidably disposed in said sleeve for feeding said molten metal therefrom and into said cavity; second piston transfer means for supplying fluid under pressure to said first piston transfer means for moving the same in one direction; a spool-like check valve member in said second piston transfer means for selectively permitting flow therethrough and preventing fluid flow therethrough; and, fluid flow control means for positioning said check valve to permit fluid flow therethrough to operate said first piston transfer means and upon filling said mold cavity being responsive for positioning said check valve to prevent further flow through said second piston transfer means, and further for subsequently operating said second piston transfer means to intensify the pressure of said fluid acting upon said first piston transfer means.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1976-05-07	1976-11-06	1977-05-08	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1980-05-07	1980-11-06	1981-05-08	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1984-05-07	1984-11-06	1985-05-08	$7700.00	Window Closed / Lapsed

Pressure intensifying apparatus for a die casting machine

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