钻孔机的进给单位dt.docVIP

外文翻译 A FEED UNIT FOR DRILLING MACHINES N. N. Esin and ~. G. Chernilov UDC 622.233.056 The feed units of drilling machines feed the drill mechanism,drill rod, and bit towards the face during drilling, and also raise and lower the drill rod. Mechanical feed units with drive from a pneumatic motor [1] are small and can develop large feed thrusts. However, they have certain drawbacks: the feed velocity is low, which increases the time required for auxiliary operations; the apparatus is complicated and insufficiently reliable in use;and the pneumatic motor is noisy.Pneumatic piston feed units [2] are simple in design and reliable in use, and give elasticity of the feed, reducing wear on the bit and permitting an increase in the productivity of drilling. However, they are large, because the thrust developed depends on the area of the pL~ton which is acted on by compressed air at a comparatively low pressure of 5-6 kg/cm 2. Nevertheless, the full rated feed thrust is quite rarely used (for example, in the last few meters of a deep borehole). thrusts.However ，， With the aim of improving the operational qualities of drilling machines, we have developed a new type of pneumatic piston feed unit. Its essential feature is that the air pressure in the feed cylinder can be several times greater than that in the air mains. This is achieved by means of a pressure converter consisting of several pistons and cylinders in series. Figure 1 shows a schematic diagram of the feed unit. The working parts comprise feed cylinder 1 with piston 9 and rod 3. The pressure converter consists of cylinder 4 with freely moving piston 5 and several single cylinders 6 with tappets 7. The rod of each tappet passes through a gland in the end wall and freely bears on the head of the preceding tappet. Air is distributed by piston valve 8. The elements of the system are connected by air ducts, one of which contains back valve 9, and another cut-off valve