Nozzle shut-off valve
AssigneeCincinnati Milacron Inc.
InventorJames E. Dawson
Life of this patent
Estimating the term…
Abstract
A nozzle shut-off valve for an injection molding machine has a plunger mounted to reciprocate in a bore so as to block the passageway of the plastic through the nozzle, a single-acting pneumatic piston and cylinder to reciprocate the plunger, to block said passageway, and a pilot passage connecting the underside of the plunger to a location upstream of the intersection of the bore and the passageway for plastic through the nozzle.
Claims12
A nozzle shut-off device for use in combination with and at a location between the nozzle and the plastication injection unit of a plastic injection molding machine, the nozzle having therethrough a substantially straight first passageway that is substantially coaxial with the exit passage from said plastication injection unit, said nozzle communicating with a mold cavity, which shut-off device comprises:
- a body member for fixedly securing to and interposing between such nozzle and such injection unit and having therethrough a shut-off passageway that is substantially straight;
- a lateral bore in said body intersecting said shut-off passageway, defining a pilot chamber on one side of said shut-off passageway and defining on the opposite side of said shut-off passageway a bore section in which the hereinafter said plunger is reciprocably supported;
- a laterally extending plunger reciprocably mounted in said bore and of a cross-section to substantially completely block the following:
- said shut-off passageway when placed laterally thereacross, said lateral bore, and said pilot chamber, and having a length sufficient when advanced laterally fully to extend across said shut-off passageway into said pilot chamber thereby to block said shut-off passageway;
- and when fully withdrawn to substantially unblock said shut-off passage;
- a pilot passage extending within said body between said pilot chamber and said shut-off passageway at a location that is upstream of the intersection of said bore with said shut-off passageway to establish communication between said upstream location and a region in said pilot chamber that is under the end of said plunger when the plunger is advanced into said pilot chamber sufficient to block said shut-off passageway.
In an injection molding apparatus comprising a chamber having a nozzle attached near one end thereof, means for forcing molten material from said chamber through a passageway formed in said nozzle, a mold having a sprue formed therein, which sprue is in communication with the passageway formed in said nozzle, and a nozzle shut-off device interposed between said nozzle and said chamber the improvement comprising:
- a body member fixedly secured to and interposed between said nozzle and said injection unit and having therethrough a shut-off passageway that is substantially straight and substantially coaxial with said first passageway;
- a lateral bore in said body intersecting said shut off passageway, defining a pilot chamber on one side of said shut-off passageway and defining on the opposite side of said passageway a bore section in which the hereinafter said plunger is reciprocably supported;
- a plunger reciprocally mounted in said bore and having at one end a pilot region, at the other end an engaging region, and a blocking region intermediately located between said pilot and engaging region, said pilot region having a cross-section to substantially block but slidably fit within said pilot chamber, said blocking region having a cross-section sufficient in size to block said shut-off passageway when moved thereacross to dispose said pilot region within said pilot chamber, said engaging region having a length sufficient to extend from said blocking region substantially coaxially along said bore to without said body, said plunger having a length sufficient when reciprocated to extend across said shut-off passageway into said pilot chamber;
- a pilot passage extending within said body between said pilot chamber and said shut-off passageway at a location that is upstream of the intersection of said bore with said shut-off passsageway to establish communication between said upstream location and a region in said pilot chamber that is under the end of said plunger when the plunger is advanced into said pilot chamber sufficient to block said shut-off passageway.
Dependencies are inferred from the claim text.