Electrically-operated construction machine

• US 8,700,246 B2
• Filed: 10/19/2011
• Issued: 04/15/2014
• Est. Priority Date: 10/22/2010
• Status: Expired due to Fees

• Current Assignee: Hitachi Construction Machinery Company Limited (Hitachi, Ltd.)
• Original Assignee: Hitachi Construction Machinery Company Limited (Hitachi, Ltd.)
• Inventors: Kurikuma, Hajime, Nasu, Katsuyoshi, Takishita, Tatsuo, Takagi, Wataru
• Primary Examiner(s): Olszewski, John R
• Assistant Examiner(s): JOHNSON, DANIEL R
• Application Number:
  US13/703,675
• Publication Number:
  US 20130197766A1
• Time in Patent Office: 909 Days
• Field of Search: 701/22, 701/50, 320/104, 320/137, 180/65.29
• US Class Current: 701/22
• CPC Class Codes: B60L 2200/40 Working vehicles
• CPC Class Codes: E02F 3/325 Backhoes of the miniature type
• CPC Class Codes: E02F 9/207 of the type electric propulsion units, e.g. electric motors or generators
• CPC Class Codes: E02F 9/2091 Control of energy storage means for electrical energy, e.g. battery or capacitors energy recovery arrangements in hydraulic or pneumatic drives E02F9/2217
• CPC Class Codes: E02F 9/2095 Control of electric, electro-mechanical or mechanical equipment not otherwise provided for, e.g. ventilators, electro-driven fans control of hydraulic driven equipment E02F9/22
• CPC Class Codes: E02F 9/2246 Control of prime movers, e.g. depending on the hydraulic load of work tools
• CPC Class Codes: E02F 9/2285 Pilot-operated systems
• CPC Class Codes: E02F 9/2296 Systems with a variable displacement pump
• CPC Class Codes: H02J 7/14 for charging batteries from dynamo-electric generators driven at varying speed, e.g. on vehicle
• CPC Class Codes: Y02P 90/60 Electric or hybrid propulsion means for production processes
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

An electrically-operated construction machine with a battery charging operation. A lock switch provides a closed contact when a lock lever in a cab is placed in an unlock position. A feed port is disposed outside the cab to accept a cable from a commercial power source. The feed port is provided with a charge start switch. A control device has a motor control function for driving an electric motor with electrical power of a main battery when a signal is input from the lock switch. A charge control function is for charging the main battery with electrical power of the commercial power source when dictated by the charge start switch. The lock switch is wire-connected so as not to output the signal to the control device even if the closed contact is provided by the lock switch when the control device exercises charge control.

Claims

1. An electrically-operated construction machine having

an electric motor serving as a drive source for a hydraulic pump, the hydraulic pump supplying hydraulic fluid to a hydraulic actuator for driving a to-be-driven member, or an electric motor for driving the to-be-driven member,

a battery serving as an electrical power source for the electric motor,

a feed port disposed outside a cab to make a cable connection to an external power source,

a lock lever disposed inside the cab to switch between an unlock position and a lock position,

a lock switch that provides a closed contact when the lock lever is placed in the unlock position and an open contact when the lock lever is placed in the lock position,

a control device having a motor control function and a charge control function, the motor control function for driving the electric motor with electrical power supplied from the battery when a signal is input from the lock switch and stopping the electric motor when the signal is not input from the lock switch, the charge control function for charging the battery with electrical power supplied from the external power source,

a key switch disposed inside the cab and placed in a start position or in a stop position, and

a first start circuit that starts the control device by supplying electrical power from the electrical power source to the control device when the key switch is placed in the start position, the electrically-operated construction machine comprising:

a charge switch that is disposed on the feed port and capable of dictating start of the control device and exercise of charge control; and

a second start circuit that supplies electrical power from the electrical power source to the control device to start the control device and exercises charge control when the key switch is in the stop position and the charge switch dictates start of the control device and exercise of charge control;

wherein, when the control device is started by the second start circuit to exercise charge control, the electric motor is not driven even if the lock switch provides the closed contact.

2. The electrically-operated construction machine according to claim 1,

wherein the lock switch is connected to the electrical power source through the first start circuit so that when the control device is started by the second start circuit to exercise charge control, the first start circuit is opened to prevent the lock switch from outputting the signal to the control device no matter whether the closed contact is provided by the lock switch and inhibit the electric motor from being driven.

3. The electrically-operated construction machine according to claim 2,

wherein the feed port is provided with an openable and closable cover so that the charge switch operates depending on whether the cover is open or closed,

wherein, when the cover is open, the charge switch dictates start of the control device and exercise of charge control, and

when the cover is closed, the charge switch dictates stop of the control device.

4. The electrically-operated construction machine according to claim 2,

wherein the feed port is provided with an indicator lamp that indicates the status of charge control.

5. The electrically-operated construction machine according to claim 1,

wherein when started by the second start circuit to exercise charge control, the control device disables the signal input from the lock switch to inhibit the electric motor from being driven.

6. The electrically-operated construction machine according to claim 5,

wherein the feed port is provided with an openable and closable cover so that the charge switch operates depending on whether the cover is open or closed,

wherein, when the cover is open, the charge switch dictates start of the control device and exercise of charge control, and

when the cover is closed, the charge switch dictates stop of the control device.

7. The electrically-operated construction machine according to claim 5,

wherein the feed port is provided with an indicator lamp that indicates the status of charge control.

8. The electrically-operated construction machine according to claim 1,

wherein the feed port is provided with an openable and closable cover so that the charge switch operates depending on whether the cover is open or closed,

wherein, when the cover is open, the charge switch dictates start of the control device and exercise of charge control, and

when the cover is closed, the charge switch dictates stop of the control device.

9. The electrically-operated construction machine according to claim 8,

wherein the feed port is provided with an indicator lamp that indicates the status of charge control.

10. The electrically-operated construction machine according to claim 1,

wherein the feed port is provided with an indicator lamp that indicates the status of charge control.