Abstract: A drill chuck for holding a tapered end of a tubular drill bit. The chuck comprises a driving member having a tapered surface for frictional engagement with the tapered end of the drill bit, a first holding member mounted on the driving member and a second holding member mounted, in use, on the tubular drill bit. The second member has a substantially radial surface thereon for abutment with a surface 31 on the drill bit. The two holding members can be screwed together whereby abutment between the substantially radial surface on the second holding member and the surface on the drill bit urges the tapered end of the tubular drill bit into frictional driving contact with the tapered surface of the driving member.

Abstract: A pneumatic device 10 comprises a piston 12 moveable along a cylinder 10. The piston has opposite ends 18, 26 defining a space 30 therebetween. The space is divided into two chambers 30a, 30b by a housing 40 fixed relative to the cylinder and having a fluid flow control passageway 42 therethrough. The space 30 is filled with fluid, such as oil. The piston 12 is arranged such that movement thereof against a spring 16 causes the fluid to be displaced from one chamber 30a of the space 30 to the other chamber 30b through the passageway 42. The spring 16 is arranged to apply a return force to the piston 12 and the rate of return of the piston 12 is controlled by the return flow of fluid through the passageway 42. A pneumatic system 100 includes a device 10 connected between first and second members 58, 58a of a building, such as a door and door frame.

Abstract: The invention provides a pipe jack for pulling a pipe lengthwise through the ground without the necessity of excavating the ground to create a trench first, the jack including a number of hydraulic rams coupled to a set of jaws, and the jaws being hydraulically displaceable to clamp a pipe disposed between them.BACKGROUND OF THE INVENTIONThis invention relates to pipe jacks, which are known devices for use in hauling pipes, cables and the like through the ground. By disconnecting a length of pipe or like at both ends, and then pulling the pipe lengthwise, the expense and labour of creating a trench, that is removing earth from above the pipe, can be avoided. In cases where the pipe runs below a surfaced road, pavement or the like, additional substantial costs in resurfacing are avoided. A new pipe may be installed in similar manner for example by attaching the same to the trailing end of the old pipe being removed, or by threading the new pipe into the orifice created by withdrawing the old pipe.