Patent ID: 7454904

Claim:
Laying apparatus for cables, lines, or conductors, the laying apparatus having a hydraulic circuit comprising: a variable delivery feed pump for pumping oil through the hydraulic circuit; a motor, hydraulically connected to said feed pump, and able to drive laying means for laying said cables, lines, or conductors; valve means; detection means for measuring the pressure of the oil inside said hydraulic circuit and comparing the measured pressure with a pre-determined pressure value and sending a signal to said valve means, at least one command member of said feed pump for controlling delivery of said feed pump, and said valve means connected to said detection means and based upon the signal from the detection means able to modify operation of said hydraulic circuit by acting on said at least one command member of said feed pump which controls delivery of the feed pump to reduce the hydraulic delivery of said feed pump in the event that the pressure measured exceeds said pre-determined pressure value, a hydraulic actuator, wherein said at least one command member is mechanically connected to said hydraulic actuator kept in an intermediate position of balance by counteracting elastic means for balancing said actuator arranged inside respective containing chambers; wherein said detection means and said valve means are of the electronic type and comprise respectively a sensor associated with said hydraulic circuit and connected to electronic processing means and an electro-valve governed by said electronic processing means and able to be selectively driven to act on the at least one command member of said feed pump to reduce the hydraulic delivery of said feed pump; wherein said electro-valve is connected to said hydraulic actuator for sending hydraulic fluid to said hydraulic actuator in response to a signal from the detection means, a distributor valve connected to said containing chambers that axially displaces the actuator in accordance with a manual command, wherein said valve means predominates over said distributor valve in affecting the displacement of the actuator.