Hydraulic knockout device

Patent metadata

Field	Value
Publication number	US-10864573-B2
Application number	US-201815877813-A
Country	US
Kind code	B2
Filing date	Jan 23, 2018
Priority date	Jan 27, 2017
Publication date	Dec 15, 2020
Grant date	Dec 15, 2020

Abstract

A part of kinetic energy during lowering of a slide of a press machine is converted into oil hydraulic energy by a first oil hydraulic cylinder, and the converted oil hydraulic energy (hydraulic oil having boosted first system pressure) is stored in a first accumulator. The hydraulic oil having the first system pressure stored in the first accumulator is discharged in knockout process, a second oil hydraulic cylinder that functions as a knockout cylinder is raised to perform knockout operation of a product worked by the press machine. Consequently, it is possible to perform knockout operation without using a dedicated driving source such as an oil pressure source and an air pressure source, and provide a low-cost hydraulic knockout device.

First claim

What is claimed is:

1. A hydraulic knockout device comprising:
an energy conversion section configured to convert a part of kinetic energy during lowering a slide of a press machine into hydraulic energy;
an energy storage section configured to store the hydraulic energy converted by the energy conversion section; and
a knockout section configured to take out a product worked by the press machine from the press machine, the knockout section configured to convert the hydraulic energy discharged from the energy storage section into kinetic energy to knock out the product,
wherein the energy conversion section includes:
a cushion pin pressed down with lowering operation of the slide; and
a first hydraulic cylinder having a piston rod which comes into contact with the cushion pin,

wherein the energy storage section is a first accumulator configured to store hydraulic fluid displaced from a rising side pressure generating chamber of the first hydraulic cylinder through the cushion pin when the slide is lowered,
wherein the knockout section is a second hydraulic cylinder having a rising side pressure generating chamber to which the hydraulic fluid stored in the first accumulator in knockout operation is fed,
wherein the hydraulic knockout device further comprises a second accumulator configured to store hydraulic fluid having second system pressure lower than hydraulic fluid having first system pressure stored in the first accumulator,
wherein the second accumulator stores hydraulic fluid displaced from a lowering side pressure generating chamber of the second hydraulic cylinder in the knockout operation, and feeds the hydraulic fluid to the rising side pressure generating chamber of the first hydraulic cylinder with rising of the slide to raise the cushion pin,
wherein a hydraulic closed circuit in which the hydraulic fluid is pressurized and filled is comprised of the first hydraulic cylinder, the second hydraulic cylinder, the first accumulator and the second accumulator, and
wherein the hydraulic closed circuit does not include a hydraulic pump configured to pressurize and feed the hydraulic fluid.

2. The hydraulic knockout device according to claim 1 ,
wherein the hydraulic closed circuit further includes a cushion pressure generating line connected to the rising side pressure generating chamber of the first hydraulic cylinder, a rising pressure generating line connected to the rising side pressure generating chamber of the second hydraulic cylinder, a lowering pressure generating line connected to the lowering side pressure generating chamber of the second hydraulic cylinder, a first system pressure line connected to the first accumulator, and a second system pressure line connected to the second accumulator, and
wherein the hydraulic knockout device further comprises:
a first check valve that is disposed between the cushion pressure generating line and the first system pressure line, the first check valve configured to allow flow of hydraulic fluid from the cushion pressure generating line to the first system pressure line;
a second check valve that is disposed between the cushion pressure generating line and the second system pressure line, the second check valve configured to allow flow of hydraulic fluid from the second system pressure line to the cushion pressure generating line;
one or a plurality of first solenoid valves that are disposed between the rising pressure generating line and the first system pressure line, and between the rising pressure generating line and the second system pressure line, the one or a plurality of first solenoid valves configured to connect the rising pressure generating line to the first system pressure line in the knockout operation, and connect the rising pressure generating line to the second system pressure line after termination of the knockout operation; and
one or a plurality of second solenoid valves that are disposed between the lowering pressure generating line and the first system pressure line, and between the lowering pressure generating line and the second system pressure line, the one or a plurality of second solenoid valves configured to connect the lowering pressure generating line to the second system pressure line in the knockout operation, and connect the lowering pressure generating line to the first system pressure line after termination of the knockout operation, wherein
the hydraulic fluid is pressurized and confined in the hydraulic closed circuit, hydraulic fluid in the first system pressure line is pressurized only by the hydraulic fluid displaced from the rising side pressure generating chamber of the first hydraulic cylinder through the cushion pin during the lowering of the slide in one cycle period of the press machine.

3. The hydraulic knockout device according to claim 2 , wherein
the first solenoid valve is a single solenoid valve configured to switch connection between the rising pressure generating line and the first system pressure line, or connection between the rising pressure generating line and the second system pressure line, and
the second solenoid valve is a single solenoid valve configured to switch connection between the lowering pressure generating line and the first system pressure line, or connection between the lowering pressure generating line and the second system pressure line.

4. The hydraulic knockout device according to claim 2 , wherein
the first solenoid valve includes a plurality of solenoid valves including a 1st-1 solenoid valve configured to switch connection or disconnection between the rising pressure generating line and the first system pressure line, and a 1st-2 solenoid valve configured to switch connection or disconnection between the rising pressure generating line and the second system pressure line, and
the second solenoid valve includes a plurality of solenoid valves including a 2nd-1 solenoid valve configured to switch connection or disconnection between the lowering pressure generating line and the first system pressure line, and a 2nd-2 solenoid valve configured to switch connection or disconnection between the lowering pressure generating line and the second system pressure line.

5. The hydraulic knockout device according to claim 2 , wherein
the first solenoid valve and the second solenoid valve each are a poppet type solenoid valve.

6. The hydraulic knockout device according to claim 2 , further comprising a controller configured to control the first solenoid valve and the second solenoid valve such that the second hydraulic cylinder is raised and thereafter lowered in a period from a time point when the slide of the press machine starts rising until a time point when the cushion pin starts lowering with lowering operation of the slide.

7. The hydraulic knockout device according to claim 2 , further comprising a cooling device configured to cool hydraulic fluid in the hydraulic closed circuit.

8. The hydraulic knockout device according to claim 2 , wherein
oil feeding and system pressure confining throttle valves, or throttle valves and couplers are mounted on the cushion pressure generating line, the first system pressure line, the second system pressure line, the rising pressure generating line, and the lowering pressure generating line.

9. The hydraulic knockout device according to claim 2 , wherein
a liquid feeding device including:
a tank configured to store the hydraulic fluid;
a discharge port configured to feed the hydraulic fluid to the hydraulic closed circuit;
a return port to which the hydraulic fluid is returned from the hydraulic closed circuit, the return port being connected to the tank; and
a hydraulic pump configured to feed the hydraulic fluid from the tank to the hydraulic

Assignees

• Aida Eng Ltd

Inventors

• Kohno Yasuyuki

Classifications

• B30B15/163 Primary

  for accumulator-driven presses · CPC title

• B30B15/32 Primary

  Discharging presses · CPC title

• B21J13/14 Primary

  Ejecting devices · CPC title

• B21J9/12

  operated by hydraulic or liquid pressure · CPC title

• F15B1/02

  Installations or systems with accumulators · CPC title