Patent GB-1023745-A (GB)
Title: Improvements in or relating to tool feeding arrangement for machine tools
IPC: B23Q5/26
Filed: 1964-02-26
Abstract: 1,023,745. Machine tool details. A. L. COULTER. Feb. 26, 1964 [Feb. 28, 1963], No. 8036/64. Headings B3B and B3C. A device for automatically feeding a drill or like tool comprising a frame adapted to be mounted on the tool, and a cylinder on the frame, which is subjected to compressed air on one side and liquid on the other side. A drilling machine 10, Fig. 1 (not shown), comprises a housing 14 mounted on a column 12, and supporting a drill spindle 16 driven by an electric motor 18. A mounting plate 24, Figs. 1-3 (not shown), is secured to column 12 by a cap 28, and a base-plate 22 is mounted on plate 24, and slidably and rotatably guides the drill quill 16 in an aperture 52. Piston assemblies 54, 56 are mounted on plate 22, and the pistons 80 of these assemblies, Fig. 5 (not shown), are slidable in the plate, and are connected to a drive plate 240, which is secured to quill 16 at 246, Fig. 3 (not shown). The tops of cylinders 66 are connected by a tube 106, Fig. 2 (not shown), and the bottoms of the cylinders are connected by a tube 110. A power unit 114, Figs. 1-4 (not shown) for converting pneumatic pressure to hydraulic pressure is mounted on plate 24. Unit 114 comprises a base 122, Fig. 4 (not shown), a cylinder 124, an upper manifold 126, and a valve housing 128. Base 122 is connected to a metering valve 136, Fig. 2 (not shown), by a tube 134, the manifold is connected to a relief valve 156 at 158, and a passage 150 in the manifold is connected to piston assembly 56 by a tube 166. Valve housing 128 comprises a spool 188, and is connected at 196, Fig. 6 (not shown), to air line 116, to a valve 232 by a tube 230 sealed in opening 228, and to a valve 238 by a tube 236 sealed in opening 234. In operation, cylinder 124, Fig. 4 (not shown), is filled with oil to level 394, and air enters cavity 194. A lever 324 on valve 238, Fig. 2 (not shown), is actuated to remove air from tube 236, and spool 188 slides towards end plate 208. Cavity 194 is connected with cylinder 124 through channel 144, and channel 150 and tube 166 are connected with opening 154, to thus exhaust air from piston assemblies 54, 56. Pistons 82 in these assemblies are forced upwardly, and drive plate 240 is raised, along with quill 16. Valve 232 is actuated to allow air to be exhausted from end 206 of valve housing 128, and the spool moves towards this end. Cavity 194 is connected to channel 150, and compressed air is supplied to the top of piston assemblies 54, 56, thus moving the quill downwardly. The oil from assembly 54 flows through tube 110 to assembly 56 and thence through metering valve 136, tube 134, into unit 114. The lower limit of feed is controlled by a post 395, Figs. 2, 3 (not shown), mounted on drive plate 240, which co-operates with lever 324 to control valve 238. This valve may be controlled manually by a knob 400 which co-operates with lever 234. The metering valve is controlled by a ball 392, Fig. 13 (not shown), which cooperates with a cam 410 mounted on plate 24, and the cam is shaped so as to provide a fast approach, slow feed through the cutting part of the drilling operation, a fast feed through a non-cutting part, and a slow feed through a second drilling region. In a modification, an adjustable drill is provided for the purpose of cleaning the drilled bore, and a more definite stop for depth of penetration is provided. Power unit 506, Fig. 19 (not shown), comprises three sections, a piston assembly 520, a manifold 522, and a four-way valve assembly 524. Manifold 522 has a passage 580 connected to a metering valve 582 through a tube 584, and a channel 610 connected to a pressure relief port 606. Valve assembly 524 is connected to an air pressure source at 600, to piston assemblies 514, 516, through an opening 612 and tube 816. In operation, power unit 506 is filled with oil and the system is bled of all air. Air is then supplied through valve assemblies 524 to piston assemblies 514, 516 and liquid flows from these assemblies, through metering valve 582, to unit 506. Piston 542 in unit 506 rises, forcing air from unit 506 through channel 618 to atmophere. Drive plate 518 moves downwardly and a stop 802, Fig. 18 (not shown), actuates metering valve 582 to stop flow of liquid from piston assemblies 514, 516, to arrest the drive plate and quill. The drill dwells at the bottom of the stroke due to a time delay introduced by a valve 756, Fig. 23 (not shown), which delays the flow of air from chamber 830 to atmosphere. As soon as the pressure in chamber 832 exceeds the pressure in chamber 830, spool 628 moves towards plate 630, and liquid is forced from power unit 506 through tube 584, metering valve 582, to drive the pistons in assemblies 514, 516 upwardly. A screw 826 on plate 518 actuates valve 818 to exhaust air from chamber 832 and move spool 628 ready for the next cycle. The hydraulic drive may be an attachment for a drilling machine (as shown), or it may be an integral part of the machine.