GB681626A - Improvements in or relating to soil-testing apparatus - Google Patents

Abstract

681,626. Testing physical qualities of materials. COMPAGNIE INTERNATIONALE DES PIEUX ARMES FRANKIGNOUL SOC. ANON. May 9, 1950 [June 16, 1949], No. 11500/50. Class 106 (ii). Soil-testing apparatus having a pointed member which is driven into the soil by a rod guided in an outer sheath, a seal between the lower ends of the rod and the sheath, and means for measuring the resistance encountered in driving the point and the sheath, is characterized in that it comprises a piston adapted to transmit the driving force to the rod and mounted in a hydraulic cylinder adapted to transmit the driving force to the sheath, and means for measuring the pressure effective in the said cylinder and corresponding to the force applied to said piston, the cylinder itself being submitted to a hydraulic pressure which is in turn measured to give the total driving force. The driving force is applied by a screw 23, to the head 22 of the rod 20 of a piston 4 working in a cylinder formed in a body 1. The space below the piston is filled with oil and is connected to a pressure-gauge 6 which indicates the total pressure applied to the sheath and the tip. A second piston 5 also works in a cylinder formed in the body 1 and its rod 12 acts on the rod 13 carrying the tip 14. The space above this piston is connected to a pressure-gauge 7 which indicates the pressure applied to the tip alone. The pistons have packing seals 8, 9 retained by plates 10, 11. Secured to the body 1 is a conical guide 15 which abuts the sheath 16 surrounding the rod 13. The lower end of the sheath carries a ring 19 or is formed with a groove which holds a packing 18 against a sleeve 17 integral with the tip 14. The sleeve 17 tapers upwardly and the diameter of the main part of the sheath 16 is equal to the greatest diameter of the tip 14. The resistance of the sheath is thus due only to lateral friction against the soil. The whole apparatus is suitably supported, the piston-rod 20 having a portion of square section guided in a yoke 24, itself guided for vertical movement in the support. The rod 13 and sheath 16 are made in sections, additional sections being screwed on as the driving proceeds. To withdraw the rod and sheath, the body 1 is first raised slightly and then an annular member 27 is placed around the sheath, a ring 28 being screwed above it to the sheath, and a screw 29 being engaged in the end of the rod so as to overlap the ring 28. Links 30 pivoted in the member 22 have pins which are engaged on brackets 33 on the body 1 so that when the latter is raised, the sheath and rod are also raised. In a modification, each section of the rod 13 has an enlarged lower end which is engaged, when the sheath is raised, by a shoulder at the upper end of the next lower section of the sheath.