Dual pump device for hydraulic drive working apparatus, has power transmission mechanism for transmitting power between pump shafts and another power transmission mechanism for transmitting power from pump input shaft to former pump shaft

摘要

The dual pump device (12) has a pump (48) of variable capacity with a pump shaft (66) and another pump (50) of variable cubic capacity with another pump shaft (68). A power transmission mechanism (58) is provided for transmitting power between the pump shafts while varying the rotational speed, such that the maximum cubic capacity output per unit time of the latter pump is greater than the maximum cubic capacity output per unit time of the former pump. Another power transmission mechanism (64) is designed to transmit power from a pump input shaft (44) to the former pump shaft. An independent claim is included for a hydraulic drive working apparatus with a dual pump device and a moving device.