Abstract: A laser marking apparatus, capable of marking at a high scanning speed, effectively utilizing a laser power, and providing high marking accuracy, irradiates an incident laser beam from a laser beam source onto a marking surface by raster-scanning through a raster scanning system. The raster scanning system includes an X-direction polarizing mirror, a Y-direction polarizing mirror, a field lens, and a mask. A double polarizing prism, which includes a pair of polarizing prisms (13a, 13b) for branching the incident laser beam (1) into twin laser beams, is arranged in series at an intermediate position between the laser beam source (2) and the upstream one of the X-direction polarizing mirror (3) and the Y-direction polarizing mirror (8).

Abstract: A motor grader includes a work implement operating device which permits operation of a plurality of direction control valve with reduced number of operation levers. The motor grader includes a wheeled body for traveling and carrying at least one work implement, at least one operation lever operable in a first direction for electrically generating a first operation command signal and a second direction perpendicular to the first direction for generating a second operation command signal and a mode selector selectable at least between a first mode and a second mode for generating a mode selection signal. A controller receives the first and second operation command signals and the mode selection signal for controlling different motor grader functions depending upon an input combination of the first and second operation command signals and the mode selection signal.

Abstract: A working tool unit of a construction machine, which excels in transportability and is capable of smoothly carrying out diversified types of work in a wide range, is disclosed. Therefore, the working tool unit according to the present invention includes: a first boom (31a) rockably mounted on a turning frame of a vehicle body; a second boom (3b) mounted to be rockable on the first boom; an arm (32) mounted to be rockable on the second boom; a working tool such as a bucket (33) mounted on said arm; a first boom cylinder (35) mounted on the turning frame (21) and the second boom to rock the second boom; a second boom cylinder (36) mounted on the second boom and the first boom to rock the second boom; and an arm cylinder (37) mounted on the second boom and the arm to rock the arm.

Abstract: When objects of crushing are clogged between a bottom plate and a crusher, a locking of the bottom plate that may ensue is automatically released in a self-propelled crushing machine. The machine comprises a feeder hydraulic motor (54) for reciprocating the bottom plate of a hopper and a feeder valve (50) for supplying a first port (54a) and a second port (54b) of the feeder hydraulic motor (54) with a pressurized discharged fluid from a hydraulic pump. The feeder valve (50) takes a first position (B) upon a first solenoid (55) thereof being electrically energized and takes a second position (C) upon a second solenoid (56) thereof being electrically energized. a keep relay (59) electrically energizes the first solenoid (55) and the second solenoid (56) by passing an electric current through each of them, and a first pressure switch (57) and a second pressure switch (58) are turned on when a pressure of the first port (54a) and a pressure of the second port (54b) exceeds a set pressure, respectively.

Abstract: A vehicle body levelling device for a working vehicle having outriggers 5 provided at the front and rear of a self-propelled lower running body 1 for stabilizing the vehicle body while in service wherein the inclinations of the vehicle body in the front to rear and left to right directions thereof are detected by means of a front to rear inclination detector 13 and a left to right inclination detector 14, respectively, and the lengths of the front, rear, left and right outrigger arms 6 are detected by outrigger length detectors 18 so as to calculate by a controller 10 required amount of extension of piston rods of the left and right jack cylinders 7 provided on the front and rear outriggers 5, and wherein a control valve 15 provided on each of the jack cylinders is controlled in accordance with results of the calculation, whereby the vehicle body can be levelled in a short period of time even on an inclined place.

Abstract: A door opening of an operator cab for a construction machine is enlarged so that protrusion of the door beyond a turning radius can be avoided when the door is fully opened and so that the operator cab can have a wide indoor space. Therefore, a side wall (2a) of the operator cab (2) at an opposite side to a boom of a working-machine installed on a swivel base (1) is formed to have an outer convex surface, including the door; rails (4, 5 and 6) are provided on the side wall (2a) of the operator cab (2); the door (3) is provided with rollers (7, 8 and 9) which are always engaged with the rails to slide the door for easy opening and closing operation, and the position of the door (3) when the door is locked fully open is set to be within a range of turning radius (R) of the swivel base (1) along the outer surface of side wall (2a) of the operator cab (2).

Abstract: An apparatus controls a pressure in a cylinder chamber of a hydraulic pump-motor. The cylinder chamber is formed by fitting a piston in a cylinder bore of a rotatable cylinder block, and the cylinder block is rotated so that ports going to the cylinder chambers are alternatively opened to a high pressure port and a lower pressure port that are both formed in a valve plate. The apparatus includes a first switching port formed at a top dead point side of the valve plate, the first switching port being communicated with a tank through a first open-close valve. A second switching port is formed at a bottom dead point of the valve plate, the second switching port being communicated with the high pressure port through a second open-close valve.

Abstract: A lock-up clutch by way of which input/output shafts of a torque converter are operatively connected to each other is connected to an electronic type pressure control valve. During speed changing in a transmission, the problem of interruption of torque transmission can be solved by turning off the lock-up clutch at the time when filling of one of the speed changing clutches to be next brought into an operatively engaged state with hydraulic oil is completed. Hydraulic pressure (P.sub.t) in the torque converter is exerted on the back 100 pressure portion of a piston of the lock-up clutch while hydraulic pressure (P.sub.t) in the torque converter is exerted on the proportional solenoid side of the pressure control valve, making it possible to reduce the initial hydraulic pressure. During speed changing, the lock-up clutch is not fully released from the engaged state but maintains its operative state at low pressure, causing shock from shifting the lock-up state to be reduced.

Abstract: A plasma torch can produce a uniform and intense swirl in the operating gas, and as a result further stabilize the output of the plasma jet, which results in good cutting quality, so as to extend the life of consumables or the like. This is achieved when jet ports (3) from which operating gas G is ejected are positioned such that in a transverse cross-section (2A) of a swirler (50) including the jet ports (3), a relationship between a diameter D of a swirler chamber and a minimum distance (d) from a line (2b), which is tangent to the diameter D of the swirler chamber and parallel to a projected line (3c) of an axis (3b) of the jet hole (3a), to the side end (2c), of the side of the jet port (3) adjacent to the tangential line (2b), is represented by 0<d/D.ltoreq.0.03.

Abstract: A geared steering system, which is capable of actuating rightside and leftside driving mechanisms to ensure efficient operation of a crawler vehicle, has a geared steering device (30) and a control system. The geared steering device (30) has one power input shaft (31), leftside and rightside steering brakes (38L, 38R) and leftside and rightside direct-coupled clutches (36, 44), one turn clutch (46), three planet gear trains (40, 43, 48), leftside and rightside power output shafts (32L, 32R) coupled to leftside and rightside steering brake hubs (34L, 34R), and a hydraulic turning motor (83) coupled to the turn clutch (46) with gears.

Abstract: A three-dimensional image measuring device which comprises a light source; a plane image forming unit for forming a plane image in a space in its depth direction on the basis of light emitted from the light source; a scanning unit for moving and scanning the plane image formed by the plane image forming unit in its depth direction; an object to be measured disposed in the space,where the plane image is formed; a light receiving unit for measuring strength of light scattered on a surface of the object as the plane image is moved and scanned and; a distance measuring unit for measuring the distance to the Object on the basis of the output of the light receiving unit, whereby a three-dimensional image with least reduced invisible area is easily and accurately measured in a short time without using the principle of triangulation.

Abstract: A load control unit for a bulldozer, comprising an actual tractive force detector for detecting the actual tractive force of a vehicle body; target tractive force setting switch for setting a target tractive force for an automatic blade control mode in dozing operation; and blade controller for controlling a blade to be lifted or lowered such that if there is a difference between the actual tractive force detected by the actual tractive force detector and the target tractive force set by the target tractive force setting switch when digging is started with the automatic blade control mode in dozing operation, the actual tractive force gradually comes closer to the target tractive force.

Abstract: The present invention provides a spacious operation cabin of a construction machine which has a large opening for a door, and which prevents the door from jutting out of the turning radius of the cabin when the door is opened. The outer side (2a) of the operation cabin (2) opposite to a working equipment boom installed on a turntable (1) is formed into an outwardly curved arc including the door (3), and the door (3) is adapted to be freely slidable with rails and rollers which are appropriately positioned. The position of the door (3) when it is opened is controlled to be within the turning radius (R) of the turntable.

Abstract: In a four-wheel drive traveling system for a tipper, an output side of an engine is connected to rear wheels via a power transmission, at least one variable hydraulic motor for driving the front wheels and a hydraulic pump driven by the engine are provided, and the variable hydraulic pump and the variable hydraulic motor are connected into a closed circuit. The system includes arrangements for controlling displacement of the variable hydraulic pump, for detecting slippage of the rear wheels, for setting a discharge pressure of the hydraulic pump between a high pressure and a low pressure, and for controlling the displacement of the variable hydraulic pump so that the discharge pressure is a low pressure while slippage is not caused for the rear wheels and so that the discharge pressure is a high pressure while slippage is caused for the rear wheels.

Abstract: An apparatus for guiding the traveling of a moving body along a predetermined traveling path with a high degree of accuracy by accurately and reliably determining a corrected position and a corrected traveling direction of the moving body. A moving distance of the moving body between points of reception of light beams is obtained by a counter, and a CPU calculates a corrected position of the moving body by using an angle formed by the projecting directions of the light beams, the position of installation of a reflecting mirror, and an estimated traveling direction obtained on the basis of an output of a rate gyro. A corrected traveling direction is then calculated by using the corrected position thus calculated. The corrected position is calculated by using the traveling direction thus estimatively calculated.

Abstract: A compensation system for a hydraulic circuit of a hydraulically driven vehicle for straight traveling, with left and right traveling valves having load detection ports; left and right pressure compensation valves arranged in respective pressurized fluid supply passages between a fluid pressure source and the traveling valves; and a by-pass passage for connecting together the load pressure detecting ports of the left and right traveling valves. There may be an on-off valve in the by-pass passage.

Abstract: A high speed and high load cylinder device is constructed by connecting a piston of a high speed cylinder (1) having a smaller pressure receiving area and a piston of a pressurizing cylinder (2) having a large pressurizing area. The device is provided with a hydraulic circuit for supplying a hydraulic pressure to the high speed cylinder and the pressurizing cylinder. The device has a sequence valve (5) at an intermediate position in a passage (2e) providing in the piston of the pressurizing cylinder for communicating an upper chamber (2.sub.1) and a lower chamber (2.sub.2) of the pressurizing cylinder for opening and closing the passage depending upon a pilot pressure. A pilot pressure is supplied for closing the sequence valve by supplying the pilot pressure to the sequence valve. A high speed/pressurizing switching valve (12) is provided at an intermediate position in a piping (11) supplying the hydraulic pressure to the upper chamber of the pressurizing cylinder in the hydraulic circuit.

Abstract: A geared steering device (30) selectively operates rightside and leftside driving mechanisms (2,3) of a crawler vehicle (1) for more efficient operation of the crawler vehicle. The geared steering device (30) comprises a power input drive element (33) for inputting a driving power from a prime mover (7), rightside and leftside steering brakes (38R, 38L), rightside and leftside direct-coupled clutches (36, 44), a turn clutch (46), three arrays of planet gear trains (40, 43 and 48), and power output shafts (32R, 32L) coupled to right and leftside steering brake hubs (34R, 34L). A control unit compares an actual steering ratio of a geared steering device (30) with a designated steering ratio, outputs control signals to respective solenoid valves for controlling the direct-coupled clutches, the turn clutch or a steering brake so as to cause the actual steering ratio to approximate the designated steering ratio.

Abstract: A fluid heater, capable of having a high energy density structure with an increased radiation receiving area, facilitating maintenance services and preventing intrusion of contamination substances, comprises a transparent internal pipe (11) which is open-ended at both ends and is positioned within an external pipe (12) of a fluid heating pipe unit (1). The fluid heating pipe unit (1) is provided with a fluid inlet (31) and a fluid outlet (32). The adjacent ends of the external pipe (12) and internal pipe (11) are connected to each other and sealed, and an electrical radiant heater (2) is arranged within the internal pipe (11) with a space (7) left therebetween. The ends of the electric heater (2) are removably supported by positioning members (91, 92). An inwardly directed radiation reflecting surface (12b) and/or a radiation absorbing material (12c) can be provided as part of the external tube (12).

Abstract: A three-dimensional image measuring device which comprises a light source; a plane image forming unit for forming a plane image in a space in its depth direction on the basis of light emitted from the light source; a scanning unit for moving and scanning the plane image formed by the plane image forming unit in its depth direction; an object to be measured disposed in the space where the plane image is formed; a light receiving unit for measuring the strength of light scattered on a surface of the object as the plane image is moved and scanned and; a distance measuring unit for measuring the distance to the object on the basis of the output of the light receiving unit, whereby a three-dimensional image with least reduced invisible area is easily and accurately measured in a short time without using the principle of triangulation.