Alarm system for constructional machine

• US 5,198,800 A
• Filed: 06/17/1991
• Issued: 03/30/1993
• Est. Priority Date: 06/21/1990
• Status: Expired due to Fees

• Current Assignee: Shin Caterpillar Mitsubishi Ltd. (Caterpillar Incorporated)
• Original Assignee: Shin Caterpillar Mitsubishi Ltd. (Caterpillar Incorporated)
• Inventors: Tanaka, Saburo, Iga, Makoto, Tozawa, Shoji
• Primary Examiner(s): Ng, Jin F.
• Assistant Examiner(s): MULLEN, THOMAS J
• Application Number:
  US07/716,526
• Time in Patent Office: 652 Days
• Field of Search: 340/573, 340/685-686, 340/552-557, 340/463, 340/436, 340/903, 340/691, 367/93-94, 342/27, 455/88-90, 455/100, 455/53-54, 212/153-154, 364/424.07, 200/61.44, 901/11-13, 901/46, 901/49-50
• US Class Current: 340/573.1
• CPC Class Codes: E02F 9/2033 Limiting the movement of frames or implements, e.g. to avoid collision between implements and the cabin sub-groups of E02F3/431 of E02F3/435 take precedence; for turntables E02F9/123
• CPC Class Codes: E02F 9/24 Safety devices , e.g. for preventing overload E02F9/226 takes precedence

Abstract

An excavator includes an upper structure swingably supported by a lower structure. A worker position sensor consists of a plurality of radio frequency transceivers provided in the excavator and a radio frequency transceiver carried by each of the excavation workers working within the working range of the excavator. A signal processing unit determines whether the relative distance between each worker and the excavator is either of short distance, slightly long distance or long distance and identifies the position of each worker for each of the predetermined identifying areas. A determining signal from the signal processing unit is supplied to a control unit. The control unit is connected to a drive unit which includes electro-hydraulic proportional valves for energizing actuators for positioning, swing, and traveling of the excavator. This control unit is also connected to a machine sensor which includes a swing angle sensor, a traveling level sensor, and a swing operation lever sensor. The control unit determines whether the machine is moved to approach the workers. The control unit controls the machine so that the lower structure stops or travels slowly or the upper structure swings slowly when the machine is approaching the workers and, so that the movement of the machine remains unchanged when it is moved away from the workers.

Claims

1. An alarm system for a constructional machine including an upper structure which is swingably supported by a lower structure, the alarm system comprising:

a worker position sensor for sensing the positions of workers who are working within the working range of the machine, said working range comprising a plurality of predetermined identifying areas;

distance determining means responsive to said worker position sensor for determining the relative distance between each of said workers and said machine;

workers sensing area determining means responsive to said distance determining means for identifying the positions of said workers in said plurality of predetermined identifying areas;

a machine sensor means for sensing the swing angle of said upper structure, the traveling direction of said lower structure, and the swing direction of said upper structure;

machine operation determining means responsive to said machine sensor means for determining said swing angle, said traveling direction, and said swing direction of said machine;

machine operation selecting mans responsive to said machine operation determining means for selecting one of three operational modes for said machine (stop, go, slow); and

a drive unit responsive to said machine operation selecting means for driving said machine.

2. The alarm system according to claim 1, wherein the worker position sensor includes a plurality of radio frequency transceivers provided int he machine and a radio frequency transceiver carried by each worker.

3. The alarm system according to claim 1, wherein the worker position sensor includes three transceivers, each of which has a sensing angle of 180 angles to provide substantially six identifying areas from a combination of areas overlappingly covered by the transceivers.

4. The alarm system according to claim 1, wherein the machine sensor means includes a swing angle sensor, a traveling lever sensor, and a swing operation lever sensor.

5. The alarm system according to claim 1, wherein the distance determining means and the worker sensing area determining means are incorporated into a signal processing unit which is adapted to determine whether the relative distance between the machine and the workers is either of a short distance, a medium distance, or a long distance, and to identify the position of the workers in the plurality of predetermined identifying areas.

6. The alarm system according to claim 1, wherein the machine operation determining means and the machine operation selecting means are incorporated into a control unit.

7. The alarm system according to claim 1, wherein the drive unit includes a solenoid valve for driving a working operation control valve and a plurality of electro-hydraulic proportional valves for driving a swing control valve and a traveling control valve.

8. The alarm system according to claim 7 wherein the machine operation determining means and the machine operation selecting means are incorporated into a control unit.

9. The alarm system according to claim 8, further comprising an external regulation terminal connected to the control unit for changing the size of the predetermined identifying areas and changing an output value of the plurality of electro-hydraulic proportional valves.