Patent ID: 8515594
Filing Date: 2013-08-20
Classification: B60S,B64F,F16H,G06F,Y02T

Abstract:
1. A towbarless airplane tug configured for receiving a landing gear of an airplane and towing the airplane thereby, said tug comprising: a chassis configured for receiving thereon at least a portion of said landing gear; a propulsion arrangement configured to move the tug in a direction along a trajectory and comprising a variable angle swash plate hydraulic pump coupled to a variable angle swash plate hydraulic motor and to a controllable bypass path valve, configured such that a hydraulic fluid circulates between the pump and the motor so as to activate said propulsion arrangement to increase at least one of a speed and a traction force of the tug when a bypass path is in a closed state, and at least most of the hydraulic fluid circulates across the motor via the bypass path valve so as to reduce at least one of a rotational speed and traction force of the tug when the bypass path is in a opened state; at least one force sensor configured to measure, directly or indirectly, a force exerted by said chassis on said landing gear in at least said direction due to a speed differential between said tug and said airplane; and a controller in communication with said force sensor and being configured to alter one or more parameters of movement of the tug such that the force exerted by said chassis on said landing gear is maintained below a predetermined value by regulating at least the power available to the propulsion arrangement, the pump and motor swash-plates, and the state of the bypass path valve.