Clamping unit for injection molding machine
First Claim
1. In a clamping unit for an injection molding machine, said clamping unit comprisesa stationary mold carrier,a movable mold carrier reciprocable relative to said stationary mold carrier to and from a clamping position, andhydraulic actuating means for moving said movable mold carrier to and from said clamping position and for locking said movable mold carrier in said clamping position, said actuating means defining an axis of symmetry and comprisingat least one hydraulic locking cylinder,a locking piston connected to said movable mold carrier and contained in and operable by said at least one hydraulic locking cylinder to lock said movable mold carrier in said clamping position, said locking piston in said at least one hydraulic locking cylinder defining a high-pressure chamber and a low-pressure chamber, said locking piston having at least one valve-controlled overflow passage connecting said high-pressure and low-pressure chambers,at least one hydraulic drive cylinder, operable to move said movable mold carrier to and from said clamping position;
- said at least one hydraulic drive cylinder being centered on said axis of symmetry and being connected to said movable mold carrier,at least one buffer cylinder, anda buffer piston contained in said at least one buffer cylinder and defining in said at least one buffer cylinder a buffer chamber, said buffer chamber communicating with said low-pressure chamber of said at least one locking cylinder,the improvement whereinsaid at least one buffer cylinder coaxially surrounds said at least one hydraulic drive cylinder,said buffer piston being mounted on said at least one hydraulic drive cylinder,said at least one hydraulic locking cylinder and said locking piston being symmetrically arranged with respect to said axis of symmetry, anda separate shut-off valve being operatively connected with said at least one hydraulic locking cylinder for shutting off said at least one valve-controlled overflow passage in said locking piston.
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Accused Products
Abstract
A clamping unit has a hydraulic actuating assembly including at least two locking cylinders provided with respective locking pistons, which are connected by piston rods to a movable mold carrier. Each locking cylinder contains a high-pressure chamber and a low-pressure chamber, which are adapted to communicate with each other through overflow passages formed in the associated locking piston. The overflow passages can be shut off by valve members. The hydraulic actuating assembly has an axis of symmetry, on which a drive cylinder and a buffer cylinder are centered. The drive cylinder serves to close and open the injection mold. The buffer cylinder is connected to the movable mold carrier and has a buffer chamber, which communicates with the low-pressure chambers of the locking cylinders. The locking cylinders and the buffer cylinder have steel tubes, which are connected at both ends to common cylinder covers to constitute a unit. The drive cylinder is coaxially surrounded by the steel tube of the buffer cylinder. The steel tubes of at least two locking cylinders are symmetrical to the drive cylinder.
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Citations
18 Claims
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1. In a clamping unit for an injection molding machine, said clamping unit comprises
a stationary mold carrier, a movable mold carrier reciprocable relative to said stationary mold carrier to and from a clamping position, and hydraulic actuating means for moving said movable mold carrier to and from said clamping position and for locking said movable mold carrier in said clamping position, said actuating means defining an axis of symmetry and comprising at least one hydraulic locking cylinder, a locking piston connected to said movable mold carrier and contained in and operable by said at least one hydraulic locking cylinder to lock said movable mold carrier in said clamping position, said locking piston in said at least one hydraulic locking cylinder defining a high-pressure chamber and a low-pressure chamber, said locking piston having at least one valve-controlled overflow passage connecting said high-pressure and low-pressure chambers, at least one hydraulic drive cylinder, operable to move said movable mold carrier to and from said clamping position; - said at least one hydraulic drive cylinder being centered on said axis of symmetry and being connected to said movable mold carrier,
at least one buffer cylinder, and a buffer piston contained in said at least one buffer cylinder and defining in said at least one buffer cylinder a buffer chamber, said buffer chamber communicating with said low-pressure chamber of said at least one locking cylinder, the improvement wherein said at least one buffer cylinder coaxially surrounds said at least one hydraulic drive cylinder, said buffer piston being mounted on said at least one hydraulic drive cylinder, said at least one hydraulic locking cylinder and said locking piston being symmetrically arranged with respect to said axis of symmetry, and a separate shut-off valve being operatively connected with said at least one hydraulic locking cylinder for shutting off said at least one valve-controlled overflow passage in said locking piston. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
- said at least one hydraulic drive cylinder being centered on said axis of symmetry and being connected to said movable mold carrier,
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16. In a clamping unit for an injection molding machine, said clamping unit comprises
a stationary mold carrier, a movable mold carrier reciprocable relative to said stationary mold carrier to and from a clamping position, and hydraulic actuating means for moving said movable mold carrier to and from said clamping position and for locking said movable mold carrier in said clamping position, said actuating means defining an axis of symmetry and comprising at least one hydraulic locking cylinder, a locking piston connected to said movable mold carrier and contained in and operable by said at least one hydraulic locking cylinder to lock said movable mold carrier in said clamping position, said locking piston in said at least one hydraulic locking cylinder defining a high-pressure chamber and a low-pressure chamber, said locking piston having at least one valve-controlled overflow passage connecting said high-pressure and low-pressure chambers, at least one hydraulic drive cylinder, operable to move said movable mold carrier to and from said clamping position; - said at least one hydraulic drive cylinder being centered on said axis of symmetry and being connected to said movable mold carrier,
a drive piston slidably received in said at least one hydraulic drive cylinder, at least one buffer cylinder, and a buffer piston contained in said at least one buffer cylinder and defining in said at least one buffer cylinder a buffer chamber, said buffer chamber communicating with said low-pressure chamber of said at least one locking cylinder, the improvement wherein said at least one buffer cylinder coaxially surrounds said drive cylinder, said buffer piston being mounted on said at least one hydraulic drive cylinder, said at least one hydraulic locking cylinder and said locking piston being symmetrically arranged with respect to said axis of symmetry, the improvement further comprising a displacement sensor for detecting a displacement of said movable mold carrier relative to said stationary mold carrier, fluid supply means for supplying pressure to said at least one hydraulic drive cylinder on opposite sides of said drive piston at the same time;
said fluid supply means having fluid supply passages,pressure sensors contained in said fluid supply passages for an overriding pressure control and an automatic control valve for controlling the rate at which fluid is supplied to said at least one hydraulic drive cylinder on opposite sides of said drive piston in accordance with a program under the control of said displacement sensor to control the speed of said drive piston;
said fluid supply passages leading from said automatic control valve to said at least one hydraulic drive cylinder on opposite sides of said drive piston. - View Dependent Claims (17, 18)
- said at least one hydraulic drive cylinder being centered on said axis of symmetry and being connected to said movable mold carrier,
Specification