Pneumatic or hydraulically operated linear driver

Abstract

A linear driver is provided and particularly, but not exclusively, to a linear driver for use in the field of civil engineering or construction, for example in the formation of piles or piers as foundations. The driver includes a weighted sleeve slidable relative a driving member, and a valve arrangement to control the linear movement of the weighted sleeve relative to the driving member. Closing the valve arrangement serves to stop movement of the weighted sleeve and transfer momentum to the driving member without physical impact between the weighted sleeve and the driving member.

1 . A hydraulically or pneumatically operated linear driver comprising:
 a driving members;   a weighted sleeve slidable relative to the driving member; and   a valve arrangement connected to the driving member, wherein the valve arrangement controls fluid pressure in a region between the driving member and the weighted sleeve to linearly move the weighted sleeve in a first direction and a second direction relative to the driving member;   wherein, in use, the valve arrangement is closed to stop movement of the weighted sleeve in the second direction such that a momentum of the weighted sleeve is transferred to the driving member without physical impact between the weighted sleeve and the driving member.   
     
     
         2 . The driver according to  claim 1 , wherein the weighted sleeve is external to the driving member. 
     
     
         3 . The driver according to  claim 1 , wherein the valve arrangement is located in the region between the driving member and the weighted sleeve. 
     
     
         4 . The driver according to  claim 1 , wherein the driving member comprises a first part and a second part which are connected to opposite sides of the valve arrangement. 
     
     
         5 . The driver according to  claim 4 , wherein the first part and second part of the driving member have different external dimensions. 
     
     
         6 . The driver according to  claim 4 , wherein the first part and second part of the driving member have substantially the same external dimensions. 
     
     
         7 . The driver according to  claim 1 , further comprising: an attachment means for attaching the driver to a pile former. 
     
     
         8 . The driver according to  claim 1 , wherein the driving member is a tube. 
     
     
         9 . The driver according to  claim 8 , wherein the driver, in use, surrounds a pile former. 
     
     
         10 . The driver according to  claim 9 , wherein the attachment means comprises a latch or clamp for selective engagement with the pile former. 
     
     
         11 . The driver according to  claim 1 , wherein the driving member is a solid rod. 
     
     
         12 . The driver according to  claim 11 , wherein the driving member comprises a driving flange. 
     
     
         13 . The driver according to  claim 1 , further comprising a housing, surrounding and slidably connected to the driving member, which comprises a means for attaching the driver to a support structure. 
     
     
         14 . The driver according to  claim 13 , wherein the housing comprises a cage. 
     
     
         15 . The driver according to  claim 1 , further comprising: an adjustable valve for controlling the fluid pressure applied during operation. 
     
     
         16 . The driver according to  claim 1 , further comprising: an actuator which provides a signal to close the valve arrangement before the weighted sleeve impacts the driving member. 
     
     
         17 . The driver according to  claim 16 , wherein the actuator comprises an actuator rod which is depressed by the weighted sleeve as the weighted sleeve moves in the second direction. 
     
     
         18 . The driver according to  claim 1 , further comprising: one or more sensors to monitor fluid pressures during operation. 
     
     
         19 . A driving system for use in a piling operation, comprising a driver according to  claim 1  and a mast for supporting the driver in a substantially vertical orientation. 
     
     
         20 . The driving system according to  claim 19 , further comprising: an adjustable carrier mounted between the mast and the driver to permit vertical movement of the driver relative to the mast. 
     
     
         21 . The driving system according to  claim 20 , wherein the vertical movement of the driver relative to the mast is controlled by the adjustable carrier. 
     
     
         22 . The driving system according to  claim 20 , wherein the adjustable carrier comprises a belt or chain and pulley system. 
     
     
         23 . The driving system according to  claim 20 , wherein the adjustable carrier comprises a hydraulic cylinder. 
     
     
         24 . The driving system according to  claim 19 , wherein the mast is mounted, in use, to an arm of a tracked excavator. 
     
     
         25 . The driving system according to  claim 19 , wherein the mast is mounted, in use, to a purpose built rig. 
     
     
         26 . The driving system according to  claim 19 , wherein a lower end of the mast is held in contact with the ground during use. 
     
     
         27 . A method of testing soil properties prior to a piling operation, the method comprising:
 mounting a driver according to  claim 18  to a support;   repeatedly driving an elongate member into the ground to be tested using the driver; and   monitoring and recording the pressure readings during the driving operation.   
     
     
         28 . (canceled)