GB707345A - Portable well-servicing rig - Google Patents

Abstract

707,345. Raising derrick masts. DRESSER EQUIPMENT CO. April 24, 1952, No. 10365/52. Class 78 (4) A portable derrick rig has a mast pivotally connected to a mobile base for swinging movement between substantially horizontal and vertical positions by a multi-cylinder ram, one end section of which has a fluid pressure reaction surface cooperating with a surface on an intermediate section to form a confined pressure chamber with a restricted orifice to snub relative movement during extension, and restricted outlet means to snub the retraction movement of all the sections. The ends of the sections of the ram, Figs. 6, 6a, screw into a collar 44 fitted with a gland 45 contacting the smaller section and having a sleeve 46 wiping the cylinder wall, the sleeve having grooves 47. The ends of the two lowermost cylinders are open, the third cylinder has a bottom plate with an opening 51, the fourth cylinder has a cylinder member 52 at the bottom fitted with a fluid tight gland 53 and a series of holes 54. Liquid enters the ram through a passage 32 unseating the thimble of a valve 31 so that liquid flows through large slots 33 into the cylinders 26 to 28. The topmost cylinder is extended by the pressure of fluid against the surface 52 and fluid contained in the enclosed space escapes through holes 54 into the cylinder 29 and thence through the restricted openings 34, 38. To retract the ram the direction of the fluid flow is reversed, to retract the cylinder 29 first then the lowest cylinders are retracted by pressure of the mast, the liquid passing through restricted openings 34. The derrick 14 is pivoted to a beam 12 and supports 15 pivoted to the trailer frame. The ram 20 having sections 26 to 29 is pivoted to the frame and to the mast by ears 21 and 22. In the horizontal position the mast rests on a cradle 18 and in the vertical position it abuts a bumper 19. The cylinder is operated by fluid driven by a pump controlled by a four-way valve.