| 摘要 |
508,443. Boring non - circular holes. JUNKERS FLUGZEUG - UND - MOTOREN - WERKE AKT.-GES. Sept. 6, 1938, No. 26048. Convention date, Sept. 6,1937. [Class 83 (iii)] In a device for boring holes of regular polygonal section the cutter spindle is rotated about its own axis and is also given a planetary rolling motion, the cutting point of the cutter being arranged externally to the rolling circle. The cutter 7 is secured to a shank 8 axially slidable in a spindle 1 which is eccentrically located in a carrier 5 rotatable about a central axis M by a driving shaft 6. A bevel gear 2 attached to the spindle 1 rolls on 'an internal bevel gear 4 integral with a stationary outer casing 3. The axis A of the spindle 1 is arranged at an angle a to the axis M so as to give the effect of a cone with apex at K, the point of intersection of the axis A and M, rolling inside an outer cone, and the generating point'S of the cutter is thus external to the rolling circle whose radius is represented by the perpendicular distance between the axes A, M in the plane of rotation of the cutting point. Axial adjustment of the shank 8 brings the cutter to the correct position for producing the best approximation to a straight sided polygon and may also be used to compensate for inaccuracies of the mechanism such as play in the bearings &c. The number of sides in the polygon produced is determined by the ratio of the gear 4 to the pinion 2, a ratio of 3 : 2 giving a triangle and a ratio of 4 : 3 a square. In order to produce a bore tapering either inwards or outwards towards the base the cutter 9 may be secured in a carrier 10, Fig. 2, slidable in guides 12 in the spindle 1 which are arranged at an angle B to the axis M, a line parallel to the guides passing through the cutting edge S and also passing through the intersection K of the axes A, M. Movement of the carrier 10 to produce the taper is caused by axial movement of a rod 15 having a pin 17 engaging a hole in the carrier. In another taper boring construction the cutter 9 is secured in a carrier 11, Fig. 3, movable along inclined guides 13 by a pin 18 on an axially displaceable rod 16, In the construction of Fig. 2, the cutter is arranged above the point K and in Fig. 3 below the point K, the latter being preferable for deep bores. Similar polygons of different size may be produced with the apparatus of Fig. 1, by adjusting the tool-holder 8 along the axis A and moving the cutter point radially so as to preserve the same ratio of distances of the cutter point from the axes A, M. The radial adjustment of the cutter is secured by means of a wedge &c. |
