GB1091540A - A power drill lubricating system - Google Patents

Abstract

1,091,540. Percussive drills. F. DUSS, [trading as FRIEDRICH DUSS, MASCHINENFABRIK]. April 27, 1966 [May 7, 1965], No. 18396/66. Heading B4C. [Also in Division F2] A power drill has an axially reciprocable drilling tool actuated via an air-cushion, the latter also serving to effect lubrication of the power drill by controlling the flow of lubricant from a reservoir, a valve being closed when the pressure of the air-cushion is high and being opened when the pressure is low. In an embodiment the piston 5, Fig. 1, is reciprocated in a cylinder 1 of the power drill by means of an electric motor, via gears 15, 16 and a crank-drive 3, 4. The air-cushion 6 is formed in the cylinder 1, the piston 5 forming one end of the air-cushion and a mass-element 2 forming the other end, the mass-element 2 also engaging the drilling tool. A shaft is also driven by the electric motor, via gears, and carries rollers 9, having notches 9a, Fig. 2, therein. The power-drill is provided with an oil reservoir 23, Fig. 1, which comwith the air-cushion 6 via a valve 19 and a passage 22, the latter also being connected to the interior 26 of the housing of the power drill through a radial bore 24. In use, the forward stroke of the piston 5 synchronizes with the opening of vents 7, 8 in the cylinder 1 by the rollers 9 and the air-cushion receives maximum pressure. The valve is closed by the pressure of air in the passage 22 so that oil cannot flow from the reservoir 23. The return stroke of the piston synchronizes with the closing of the vents 7, 8 and, as the pressure of the air-cushion is at a minimum, the valve 19 is opened and oil is sucked from the reservoir 23 and delivered, via the passage 22, to the aircushion 6. As the piston again makes a forward stroke, oil-entrained air is forced into the interior 26 of the housing, via the vents 7, 8 and the notches 9a in the roller 9 and via the radial bore 24. Thus the interior 26 is supplied with an oilmist. Oil mist from the air-cushion 6 may also be passed through bores in the mass element 2 to a portion 18 of the cylinder 1. Oil in the reservoir 23 may be passed to the valve 19 via capillary tubes 27, Fig. 3, or via a flexible tube the free end of which has a weight secured thereto.