GB1039153A - Machine tools with cantilever beams - Google Patents

Abstract

1,039,153. Machine tool details. GIDDINGS & LEWIS MACHINE TOOL CO. Feb. 17, 1964 [Feb. 20, 1963], No. 6516/64. Headings B3B and B3T. A sliding cantilever supporting beam 30 for the tool of a horizontal boring, drilling and milling machine, or for the ram of a planing or shaping machine, has an anti-sag means which provides a varying upward force to the outer end of the beam to counteract the deflection. A horizontal drilling boring and milling machine, comprises a bed 12, a column 16 slidable on the bed, a head stock 18 slidable on the column, and a tool spindle 26 carried by beam 30. The anti-sag means, counteracts the deflections due to the weight of beam 30, the weight of a tool or attachment mounted at its outer end, and to misalignment of parts of the machine tool. Beam 30 is formed by plates 34-37, and has a sliding fit in the headstock 18, the fit being adjustable by tapered gibs 40. Spindle 26 is fed by a screw and nut 41, 45, Fig. 3 (not shown), and beam 30 is fed by a screw and nut 43, 47. A lever 53 is disposed in beam 30 and is in contact with the latter in three spaced vertical planes I-III. Beam 30 has a pivoted follower 70, and a fixed follower 62, secured thereto, the rollers 76, 85, of which co-operate with a cam 90 so that a downward force can be applied at plane III to lever 53, which varies according to the overhang of the beam, so that the lever pivots at 135 and produces an upward force at the outer end of the beam at plane I. Cam 90 is constructed in two parts, the base 91 which is fixed to the head stock, and a tapered upper part 104 which is slidable in a channel 99 formed in base 91. Bar 104 is adjusted relative to base 91 by a screw 106, a scale 109 being provided. Notches 110-114 are provided in the bar to carry blocks 116-120 having tapers which vary and engage pins 100. The loads due to tools &c. are compensated for by a manually actuated cam-shaft 156 mounted at plane I, the cams on the shaft being of polygonal form each flat of which is designed to compensate for the weight of a different tool. In operation, cam bar 104 is set relatively to base 91, to give a predetermined slope. The beam is extended to the left, and roller 70 rides up the cam and presses follower 70 against lever 53 at 83. If the compensation is found to be incorrect due to misalignment of the machine parts, screw 106 is adjusted to vary the relative position of bar 104, and base 91 to change the cam slope.