Injection mold safety controls
OwnerRobert A. Werneckeinventor
Life of this patent
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Abstract
A contact sensing system senses the contact of two parts, such as the closure of two die parts in a molding machine, and controls a subsequent event such as the introduction of fluent molding material into the mold when closure of the die parts is sensed. One of the die parts is provided with an orifice which is covered by the other die part when the mold is closed. Sensing is achieved by delivering air through the orifice using an air line and sensing the pressure increase in the line when the orifice is closed by the other die part. A control module houses the components of the sensing system and protects the components in hostile environments.
Claims19
For use with injection molding apparatus of the type having a mold and means for injecting fluent material in to said mold, said mold including a pair of die portions movable relative to each other between a closed position defining a mold cavity into which said fluent molding material may be injected by said injection means to mold a part and an open position in which the molded part may be removed from said mold, a safety system for preventing injection of said fluent material into said mold prior to closure of said die portions, comprising:
- first and second opposing faces respectively on said pair of die portions;
- at least one aperture in said first face, said aperture being open when said die portions are in said open position thereof, said second face substantially closing said one aperture against air flow therethrough when said die portions are in said closed position thereof;
- a T connector having first, second and third branches with the second and third branches coaxially aligned and intersected by the first branch;
- a first fluid line interconnecting the first branch with said one aperture;
- a second fluid line interconnecting the second branch with an air supply means, said air supply means including a source of pressurized air and an air pressure regulator and a valve for changing the rate of pressure increase of air supply to said one aperture, said valve being connected between said regulator and said second branch whereby the changes in said rate of pressure increase affected by said pressure rate changing means alters the duration of the delay between the time said die portions complete their move to said closed position thereof and the time said enabling means enables operation of said injections means, said time delay resulting from a progressive build-up of air pressure in said air supply lines;
- a third fluid line interconnecting the third branch with a means for sensing the magnitude of air pressure in said third fluid line;
- said T connector operatively coupling said first, second and third fluid lines such that when said die portions are in said open position air pressure is reduced in said lines and sensed by said sensing means and when said die portions are in said closed position air pressure is increased in said lines and sensed by said sensing means;
- means automatically responsive to said sensing means for enabling said injection means to inject said fluent material into said mold when the magnitude of said air pressure sensed by sensing means is at least as great as a preselected value thereof, and for disabling said injection means when said sensed magnitude is less than said preselected value.
Apparatus for controlling two consecutive operations in a machine in timed relationship to each other, the first operation including the movement of two spaced apart members into contact with each other, the second operation commencing only after said members are in contact with each other, comprising:
- an orfice in one of said members through which a compressible fluid may flow;
- means carried by the other of said members for closing said orifice against fluid flow when said members are in contact with each other;
- a T connector having first, second and third branches with the second and third branches coaxially aligned and intersected by the first branch;
- a first fluid line interconnecting the first branch with said one aperture;
- a second fluid line interconnecting the second branch with a fluid supply means for supplying said compressible fluid under pressure to said orifice, said fluid supply means causing said fluid to flow through said orifice when said members are spaced apart and compressing said fluid when said members contact each other and said orifice is closed;
- a third fluid line interconnecting the third branch with a means for sensing the pressure of said fluid supply to said orifice by said supply means;
- first control means responsive to said sensing means for producing the first electrical control signal for initiating said second operation when the fluid pressure sensed by said sensing means exceeds a preselected value thereof, the compressibility of said fluid resulting in a time delay between the closing of said orifice and the build-up of said fluid pressure to said preselected value thereof;
- second control means for sensing the movement of at least one of said members and for producing a second control signal when movement of said one member is sensed;
- and
- third control means responsive to said first and second control signals for initiating said second operation only upon receipt of both of said first and second control signals;
- and
- means for varying the rate at which fluid is supplied by said fluid supply means to said orifice whereby to control the amount of said time delay.
Apparatus for sensing the closure of first and second die parts or the like, comprising:
- a sensing line terminating in an orifice in said first part through which a compressible fluid may flow;
- a surface on said second part for engaging said first part and for closing said orifice against fluid flow therethrough upon closure of said die parts;
- a pressurized source of said fluid for causing said fluid to flow through said sensing line and said orifice when said die parts are open and compressing said fluid in said sensing line when said die parts are closed;
- and
- a self-contained control module including:
- a fluid manifold including first, second, and third branches with the second and third branches coaxially aligned and intersected by the first branch;
- said first branch being connected to said sensing line;
- a valve means interconnected between said second branch and said pressurized source for regulating the pressure and rate of delivery of fluid delivered through said sensing line to said orifice from said pressurized source;
- a sensing means connected to said third branch for sensing the pressure of said fluid in said sensing line and for producing an electrical control signal when the sensed pressure reaches a preselected value, said sensing means including a fluid inlet.
Dependencies are inferred from the claim text.