by way of a third receiving line 140 a relief valve 142 is interposed in the third receiving line 140 and a flow control valve 144 is also interposed in the third receiving line 140 between the relief valve 142 and the lower port 120 of the third hydraulic cylinder 52 the pressure line 126 is also connected at an end 146 to a pump 148 which is in turn connected to a reservoir 150 the pump 148 is positioned to draw hydraulic fluid from the reservoir 150 and pump the hydraulic fluid under pressure through the pressure line 126 and through the first second and third receiving lines 128 134 and 140 into the fluid areas 68 92 and 116 of the first second and third hydraulic cylinders 48 50 and 52 any commercially available pump capable of delivering hydraulic fluid under sufficient pressure can be employed as the pump 148 for example desirable results have been obtained wherein the pump 148 is a j s barnes corporation high pressure gear pump no 736049r the pump 148 can be powered by any convenient method such as by use of an electric motor 152 in this embodiment the electric motor 152 is a five horsepower ac electric motor geared to provide the proper drive the pressure line 126 and the first second and third receiving lines 128 134 and 140 can be constructed of any material and in any conventional manner known to the art for example pressure hose or hydraulic line may be used in this embodiment of the invention it has been found satisfactory to use 1 2 diameter pressure resistant pipe rated at 5000 p s i the hydraulic assembly 16 also includes a return line 154 with an.