Tube feeding device for use in charging shotholes with explosive through a pipe or tube

A device for feeding a tube into and out of a shothole for use in charging the shothole with an explosive, comprising

• a pair of clamping devices each having therethrough an axial bore through which a tube is adapted to be advanced,
• means guiding said clamping devices for reciprocable movement in a common path, and with their axial bores aligned coaxially of one another so that said tube may extend coaxially through both of said bores during the feeding thereof,
• each of said clamping devices including a fluid pressure-operated wall of flexible material forming the axial bore through the device, and disposed selectively to grip the tube extending through said bore,
• a pair of parallel cylinders each having a reciprocable piston rod operatively connected to one of said clamping devices to impart reciprocation thereto,
• means for connecting said cylinders to a supply of fluid under pressure, and operative to cause said fluid to impart reciprocation to said piston rods simultaneously to move said clamping devices alternately towards and away from each other,
• means including said guiding means for selectively and intermittently connecting said clamping devices to said fluid supply, when said devices are in one of their limit positions, and operative to convey fluid under pressure from said supply to the flexible walls in said clamping devices thereby to cause said walls momentarily to collapse radially inwardly and one at a time into gripping engagement with the tube extending through said bores, whereby during the period when one of said clamping devices is in gripping engagement with said tube the other clamping device will not be in operation, and will be moving in a direction opposite to that in which the tube is being fed, and
• means for selectively changing the feeding direction of said tube by changing the mutual gripping sequences of said clamping devices.