Abstract: A device for controlling the operation of power excavators includes a control lever which is handled simply by one hand, which is different from the prior art systems having multiple control levers necessarily handled by both hands. The control lever consists of a plurality of links which are jointed together in such a way that the intuitive handling directions of the links are identified with the actual moving directions of the actuators. The control lever thus adds significant convenience for the operator when operating the actuators of the excavator. An excavator with the above control device can be easily and effectively operated by an unskilled operator even for delicate work such as a land finishing work or loading work, both of which tasks are generally known in the art to require a highly-skilled operator.

Abstract: The present invention provides a current control apparatus for a DC motor system having a motor field coil and a motor armature and driven by the power of a battery, and a chopper transistor for controlling the amount of the current supplied to the DC motor from the battery, which current control apparatus has current amplifying means for detecting the current amount at the rear end of the motor and amplifying the current value; on-off control means for comparing the input current with the current supplied from the current amplifying means and outputting an on-off control signal according to the current amount; and a microcomputer for controlling the duty value of the pulse wave of a predetermined frequency occurring in accordance with the on-off control signal from the on-off control means and controlling the on-off time of the chopper transistor.

Abstract: A structure for mounting an actuating rod stroke sensor to a hydraulic cylinder is disclosed. The sensor mounting structure has a sensor holder which is mounted to a predetermined portion of a cylinder head. A circuit board is tightly set in the sensor holder and holds the stroke sensor in the sensor holder. The above structure improves the operational precision of the stroke sensing operation and effectively fixes the sensor to the cylinder. The structure also protects the stroke sensor from the frictional heat generated during the reciprocating motions of the actuating rod, thereby lengthening the expected life span of the stroke sensor.

Abstract: A working unit of construction equipment with an attachment self leveling function is disclosed. The working unit includes an attachment self leveling linkage. The linkage automatically maintains the desired angle of the attachment relative to the reference or ground surface, thereby maintaining the horizontal position of the attachment without any motion for controlling the bucket cylinder while lifting up the attachment from the initial position to the uppermost position by the arm-up motion during the operations of construction equipment. The attachment self leveling linkage has a simplified construction, thereby being easily produced and installed at a lower cost and lightening the weight of the working unit. The linkage thus improves the operational efficiency of the working unit.

Abstract: A distributed control system for a heavy construction machine, comprising a plurality of modules into which components in the heavy construction machine are classified according to functions and positions. The modules are individually controlled and each of them exchanges information with a different one of the modules through a single line. According to the present invention, the number of wires is significantly reduced, thereby making the wiring in assembling and repairing very easy. Also, when the heavy construction machine fails, the corresponding portion can readily be grasped and repaired. Further, the model and function of the heavy construction machine can readily be modified.

Abstract: A working unit of construction equipment with an attachment self leveling function is disclosed. The working unit includes an attachment self leveling linkage. The linkage automatically maintains the desired angle of the attachment relative to the reference or ground surface, thereby maintaining the horizontal position of the attachment without any motion for controlling the bucket cylinder while lifting up the attachment from the initial position to the uppermost position by the arm-up motion during the operations of construction equipment. The attachment self leveling linkage has a simplified construction, thereby being easily produced and installed at a lower cost and lightening the weight of the working unit. The linkage thus improves the operational efficiency of the working unit.

Abstract: A working unit of construction equipment with an attachment self leveling function is disclosed. The working unit includes an attachment self leveling linkage. The linkage automatically maintains the desired angle of the attachment relative to the reference or ground surface, thereby maintaining the horizontal position of the attachment without any motion for controlling the bucket cylinder while lifting up the attachment from the initial position to the uppermost position by the arm-up motion during the operations of construction equipment. The attachment self leveling linkage has a simplified construction, thereby being easily produced and installed at a lower cost and lightening the weight of the working unit. The linkage thus improves the operational efficiency of the working unit.

Abstract: Current control apparatus of DC motor includes current amplifying means for detecting the current amount at the rear end of the motor and amplifying the current value; on-off control means for comparing the input current with the current supplied from the current amplifying means and outputting an on-off control signal according to the current amount; and microcomputer for controlling the duty value of the pulse wave of a predetermined frequency occurring in accordance with the on-off control signal from the on-off control means and controlling the on-off time of the chopper transistor.

Abstract: The present invention relates to a wear resistant materials having excellent wear resistance and a method of manufacturing the materials, comprising a process that lugs are formed on surface by electro-sparking welding apparatus having a vibrator, and a process that coats solid lubricant layer having wear resistance on the said lugs (ref. FIG. 3).

Abstract: A device and method for automatically vibrating the working members of a power construction vehicle such as a power excavator is disclosed. The device and method effectively change both the amplitude of vibration and the number of vibrations of a working member in proportion to a levering angle of an associated control lever during an excavating, breaking or ground hardening operation of a construction vehicle. The automatic vibration device is thus free from any select switch. The device simplifies the construction of the hydraulic system and more easily controls the automatic vibration operations, and thereby is convenient to operators.

Abstract: Disclosed is a safety lever apparatus and a method of using the safety lever apparatus for a heavy equipment having an operating box which is pivotally mounted to one side of an operating seat, capable of preventing an incorrect operation of the heavy equipment due to a physical contact between a working lever and an operator of the heavy equipment at the time that the operator leaves from an operating room during the operation of the heavy equipment. The safety lever apparatus comprises an operating box which is rotatably mounted to an operating seat. A complex lever of the safety lever apparatus is pivotally fixed to the operating box and is operated by an operator of the equipment in order to allow the operator for going out of an operating room. A first cam member of the safety lever apparatus blocks or transmits an operating force which is transmitted from the operating member to a working device. The first cam member rotates together with the complex lever.

Abstract: A process for automatically controlling power excavators is disclosed. In the process, the motions of the working members in accordance with lever handling motions of an operator are stored in a controller and reproduced to approximately conduct the operation. The operational errors of the reproduced motions of the working members are corrected and compensated in accordance with newly inputted lever handling motions of the operator while approximately conducting the operation, thereby accomplishing the desired operation. The process optimally controls the excavators regardless of working conditions, thereby improving the operational precision of the excavators. The above process does not need to use any sensors.

Abstract: A fluid joining device for construction vehicles is disclosed. The device has a bypass line control valve which is mounted to a second center bypass line of the second pump. The bypass line control valve normally opens the second center bypass line but selectively closes the second center bypass line in response to a pilot pressure. A second pilot line control valve is mounted to a second pilot line and controls the second pilot line in response to an outside signal. The second pilot line extends from the first pilot line control valve and selectively drives the first pilot line control valve. The device selectively performs the fluid joining function in accordance with operational conditions of the actuators, thus smoothly operating the actuators and improving operational effect of the construction vehicle.

Abstract: A working unit of construction equipment with an attachment self leveling function is disclosed. The working unit includes an attachment self leveling linkage. The linkage automatically maintains the desired angle of the attachment relative to the reference or ground surface, thereby maintaining the horizontal position of the attachment without any motion for controlling the bucket cylinder while lifting up the attachment from the Initial position to the uppermost position by the arm-up motion during the operations of construction equipment. The attachment self leveling linkage has a simplified construction, thereby being easily produced and installed at a lower cost and lightening the weight of the working unit. The linkage thus improves the operational efficiency of the working unit.

Abstract: An apparatus and a method for controlling a moving speed of each bucket and a moving speed ratio between each bucket, to be proportional to a degree of operation of each operation indicator and an operation ratio between each operation indicator, regardless of changes in various working conditions or load pressures.

Abstract: A hydraulic system for driving an axial piston type hydraulic motor wherein a swash plate can tilt at a right angle relative to a shaft.

Abstract: Disclosed is an apparatus for measuring a dimension of a manufactured article to be worked on a cylindrical grinding machine. The apparatus includes non contact-type measuring sensors capable of measuring the outer diameter and cylindricity of the manufactured article while the manufactured article is mounted on the cylindrical grinding machine. The apparatus comprises a main body which is positioned above a cylindrical grinding machine. The main body includes a bed having a through opening formed through a center thereof and a plurality of support members for supporting the bed. A sensor attachment of the apparatus is positioned on the bed. A sensor attachment includes at least two pairs of non contact-type measuring sensors. The pairs of non contact-type measuring sensors are spaced opposite from each other in order to measure the outer diameter and cylindricity of the manufactured article.

Abstract: A device and method for selecting a control mode in a power construction vehicle is disclosed. The device has a control mode select switch which selects a function for setting new matching relations between the control levers and the proportional control valves. A controller sets the new matching relations and stores the new matching relations, and controls the actuators in accordance with the new matching relations. In the control mode selection method, one operational motion of an actuator is primarily selected and displayed on a display means. Thereafter, a voltage signal indicative of a levering angle of a control lever associated with the selected actuator is output, thus setting a new matching relation between the control lever and an associated proportional control valve. The above process is repeated in order to continuously set and store new matching relations between the control levers and proportional control valves associated with the other actuators.