Abstract: A timber crusher capable of sufficiently exhibiting an effect of preventing timber pieces from scattering to an outside and also preventing damage to the crusher is provided. To this end, in the timber crusher comprising, on a base, a crusher for crushing timber into pieces and a rotary tub for guiding the timber to the crusher, a hopper (5) having an upwardly open shell part (5b) and guiding the charged timber to the rotary tub (3) is provided at an opening of the rotary tub (3). The hopper (5) is inclined with respect to the horizontal and is tiltable. Further, the hopper (5) may be provided with a scattering prevention cover (7) for preventing timber from scattering to an outside from an inside of the rotary tub (3).

Abstract: The present invention is concerned with an apparatus for controlling a straight excavating operation with a hydraulic excavator such as a power shovel or the like machine including three working units, i.e., a boom, an arm and a bucket. When the straight excavating operation is performed, a hydraulic pressure of hydraulic oil in a hydraulic chamber on the boom lowering side of a boom cylinder is conducted to a drain tank while maintaining a predetermined set pressure, and a hydraulic pressure of hydraulic oil in a hydraulic chamber on the boom raising side of the boom cylinder is conducted to the drain tank via a check valve which serves to inhibit the hydraulic oil from flowing from the hydraulic chamber on the boom raising side of the boom cylinder to the drain tank, whereby the boom is held in the so-called floated state so as to enable a straight excavating operation to be performed merely by actuating the arm and bucket.

Abstract: Hydraulically-operated equipment such as travelling equipment or working equipment for use in construction machinery such as a power shovel, shoveldozer and bulldozer. The hydraulically-operated equipment comprises a hydraulic driving mechanism actuated by hydraulic pressure, a hydraulic pressure supplying device for supplying hydraulic pressure to a hydraulic pipeline system for the hydraulic driving mechanism and a controller for controlling the hydraulic pressure supplying device such that the supplying rate at which hydraulic pressure is supplied to the hydraulic pipeline system according to the supply of hydraulic pressure is decreased in a specified period after a dead zone period in which hydraulic pressure starts to rise. This arrangement prevents an operational lag in the hydraulic driving mechanism as well as a shock at the time of start-up and shut-down.

Abstract: An operator's actions for achieving a desired operation of a machine's actuator can be memorized in a teaching mode and the memorized information can be used for automatically reproducing the desired operation in a play back mode, to alleviate the operator's burden. A failure in the play back mode caused by the difference in the conditions under which the play back mode and the teaching mode are conducted can be eliminated, and the operation can be allowed to be continued in the manual mode even if a failure occurs in an automated operation control system. In order to achieve these, when a correction operation by the operator is detected in the play back mode, the play back mode is interrupted and the correction operation is processed with priority to the play back operation.

Abstract: In a hydraulic drilling machine with a boom, arm and bucket as working parts, one or more of the working parts can be vibrated automatically to perform effective drilling with reduced resistance in various types of operations when the soil changes. Adequate vibration can be automatically generated by setting the working mode (Bo, A, Bu, Sk) and vibration mode (L, M, S) according to the soil or operation form beforehand and by setting the automatic vibration mode. Furthermore, since the control input of the working part lever can be added to the automatic vibration, simple and minute repeated operations, such as pressure-shifting, sifting or drilling conducted while the bucket is vibrated, can be performed readily and uniformly without exhausting the operator, and workability can thus be greatly improved.

Abstract: A teaching and playback method for a work machine that is applicable to construction equipment such as a hydraulic excavator to automatize operation. Data on the operator's operation of work machine actuators is stored, and the stored data is reproduced so that the same operation as that by the operator is automatically performed. The method is adapted to effect exactly the same operation as what has been taught even when, during playback, the load on the actuators has varied from the level applied during the teaching. For this purpose, the pump discharge amount and the amounts of flow supplied to the actuators which are present during the teaching are stored. During playback, when the load has varied, and the pump discharge has changed, the engine output is controlled in such a manner that the actual pump discharge becomes equal to the amount stored during the teaching.

Abstract: An apparatus for controlling hydraulic pumps for a construction machine wherein the construction machine includes first and second hydraulic pumps adapted to be driven by an engine and hydraulic actuators hydraulically connected to the first and second hydraulic pumps via first and second actuating valves is disclosed. A controlling section calculates extra horse powers .DELTA.HP.sub.1 and .DELTA.HP.sub.2 based on reference allowable absorptive horse powers set relative to the first and second hydraulic pumps and actual absorptive horse powers (HP.sub.01) and (HP.sub.02) derived from the first and second hydraulic pumps. In addition, the controlling section calculates allowable discharge capacities (V.sub.1P) and (V.sub.2P) based on the number (N) of revolutions of the engines, pressures (P.sub.1) and (P.sub.2) of hydraulic oils discharged from the first and second hydraulic pumps, the extra horse powers .DELTA.HP.sub.1 and .DELTA.HP.sub.2 and allowable discharge capacities (V.sub.1P) and (V.sub.2P).

Abstract: A service valve circuit of a hydraulic excavator connected beforehand for use in controlling a special attachment in addition to a prescribed actuator control valve. The service valve circuit comprises a confluence valve 17 for performing electromagnetic proportional flow rate control, disposed in a confluence circuit 16 in communication with the section between inflow circuits 3F and 3R of two variable pumps 2F and 2R, an electrical switch 21 for switching the confluence valve 17 on or off according to a required flow rate and a volume 22 for adjusting the quantity of flow after passing through a confluence valve 17 in a range of flow for a maximum of one to two pumps. Since the requirement of confluence with respect to a required quantity of flow for a special attachment e and the quantity of confluence are set in advance, there will be no excess or shortage of the quantity of confluence.