Cargo handling machine including force control

• US 6,370,970 B1
• Filed: 09/07/1999
• Issued: 04/16/2002
• Est. Priority Date: 03/18/1998
• Status: Expired due to Fees

• Current Assignee: Hiromitsu Satoh, Hosokawa, Satoshi
• Original Assignee: Hiromitsu Satoh, Hosokawa, Satoshi
• Inventors: Hosokawa, Satoshi, Satoh, Hiromitsu
• Primary Examiner(s): NOORI, MAX H
• Application Number:
  US09/391,263
• Time in Patent Office: 952 Days
• Field of Search: 738/623.81, 738/623.91, 738/625.6, 737/74, 738/16
• US Class Current: 73/862.56
• CPC Class Codes: B66C 13/18 Control systems or devices exclusively for rope, cable, or chain winding mechanisms B66D1/40
• CPC Class Codes: B66C 23/005 with balanced jib, e.g. pantograph arrangement, the jib being moved manually
• CPC Class Codes: G01L 5/103 using sensors fixed at one end of the flexible member

Abstract

The present invention aims at improving operability of a cargo handling machine by applying thereto a force control method. According to the force control method, a force sensor detects an anti-gravitational lift force that makes it possible to raise the cargo by holding an operating section, a hoisting force of the cargo handling machine is amplified in accordance with the lift force and the cargo is raised or lowered by the lift force and the hoisting force.

Claims

1. A cargo handling machine utilizing a force control method, the machine comprising:

an elevation mechanism to raise and lower a cargo;

a drive source for driving the elevation mechanism to raise and lower a cargo;

an operating section coupled to the elevation mechanism and having a force sensor arranged to transmit a signal indicative of a vertical force applied to the operating section by a user;

a detector coupled to the elevation mechanism to transmit a signal indicative of the vertical direction of movement of the elevation mechanism; and

a control section having an electropneumatic proportional valve for controlling the drive source, the control section configured to operate the cargo handling machine in a first mode wherein the control section causes the drive source to generate a hoisting force that is amplified in accordance with the signal from the force sensor, and a second mode wherein the hoisting force is reduced at an attenuated time rate of change in response to a decrease in the signal from the force sensor and a signal from the detector indicating vertically downward movement of the elevation mechanism.

2. A cargo handling machine utilizing a first control method, the machine comprising:

an elevation mechanism to raise and lower a cargo;

a force cylinder for driving the elevation mechanism to raise and lower a cargo;

an operating section coupled to the elevation mechanism and having a force sensor arranged to transmit a signal indicative of a vertical force applied to the operating section by a user;

a detector coupled to the elevation mechanism to transmit a signal indicative of the vertical speed and direction of movement of the elevation mechanism; and

a control section having an electropneumatic proportional valve for controlling the force cylinder and a flow rate switching valve, the control section configured to operate the cargo handling machine in a first mode wherein the control section causes the force cylinder to generate a hoisting force that is amplified in accordance with the signal from the force sensor, and a second mode wherein the control section causes the flow rate switching valve to limit the rate of air supplied to the cylinder so as to limit a speed at which the cargo ascends.

3. A cargo handling machine utilizing a force control method, the machine comprising:

an elevation mechanism to raise and lower a cargo;

a force cylinder for driving the elevation mechanism to raise and lower a cargo;

an operating section coupled to the elevation mechanism and having a force sensor arranged to transmit a signal indicative of a vertical force applied to the operating section by a user, and a switch selectively activated by the user; and

a control section having an electropneumatic proportional valve for controlling the force cylinder and a flow rate switching valve, the control section configured to operate the cargo handling machine in a first mode wherein the control section causes the force cylinder to generate a hoisting force that is amplified in accordance with the signal from the force sensor, and a second mode wherein the control section causes the flow rate switching valve to limit the flow rate of air supplied to the force cylinder so as to limit the speed at which the cargo ascends or descends.

4. A cargo handling machine utilizing a force control method, the machine comprising:

an elevation mechanism to raise and lower a cargo;

a force cylinder for driving the elevation mechanism to raise and lower a cargo;

an operating section having a force sensor arranged to transmit a signal indicative of a vertical force applied to the operating section by a user;

an acceleration detector coupling the operating section to the elevation mechanism and transmitting a signal indicative of the vertical acceleration of the operating section;

a detector coupled to the elevation mechanism to transmit a signal indicative of the vertical direction of movement of the elevation mechanism; and

a control section having an electropneumatic proportional valve for controlling the force cylinder, a pressure regulating valve for supplying a preselected fluid pressure, and an electromagnetic valve for selectively introducing the preselected pressure from the pressure regulating valve to an upper chamber of the force cylinder, the control section configured to operate the cargo handling machine in a first mode wherein the control section causes the drive source to generate a hoisting force that is amplified in accordance with the signal from the force sensor, and a second mode wherein the control section causes the electromagnetic valve to introduce the preselected pressure to the upper chamber of the force cylinder in response to a rate of change in the signal from the force sensor that exceeds a preselected value, a signal from the acceleration detector indicating a vertically upward acceleration of the operating section, and a signal from the detector indicating vertically upward movement of the elevation mechanism.