| 摘要 |
562,818. Dividing-engines. LEWIS, W. W. Feb. 16, 1943, No. 2513. [Class 97 (iii)] [Also in Group XXII] A dividing-bead capable of carrying a work piece whilst being machined or shaped, has an index plate carrying a projecting pin adapted to engage a stationary stop for determining angular displacements of the work, the pin being inserted in any one of a series of spaced notches on the plate for giving a course adjustment and the stationary stop being tangentially adjustable to give the fine adjustment. The index plate 1 is rotatably mounted in a bracket 3 by means of a shaft 2 secured thereto and is provided with notches 6 spaced 30 degrees apart around the periphery, each notch having mutually perpendicular sides 6a, 6b to which the pin 7 is attached by a screw 8a. The pin has a cylindrical portion 7b adapted to engage the end of the stop 9 adjustably held in a split clamp 8 on the bracket 3, and a screw 13 also carried by the bracket 3 in a split clamp 14 may be used to hold the pin 7 in contact with the stop 9. A micrometer 10 carried by a clamp 12 on the bracket 3 engages the end of the stop 9, and in operation, the micrometer is set at zero and the length of the stop 9 is arranged so that its end face in contact with the pin 7 will lie in a plane perpendicular to the axis of the stop and passing through the axis of the shaft 2. To displace a work-piece attached to the plate 1 through an angle of more than 30 degrees, the plate is rotated and the pin 7 is moved to the appropriate notch 6. The stop 9 is then adjusted by the micrometer to give the final setting of less than 30 degrees, the linear movement of the stop being equal to the radius of the index plate up to the centre of the pin 7 multiplied by the sine of the angle through which the plate is to be moved. The plate is then rotated to bring the pin 7 into contact with the stop again, and may be clamped in this position by the screw 13 during machining of the work. The stop 9 may be replaced by others of different length in order to keep the adjustment within range of the micrometer, and gauge blocks may be placed between the stop and an abutment such as the clamp 12 instead of using a micrometer. The bracket 3 may be mounted on a base 16 by means of a shaft 15 perpendicular to the shaft 2, a flange 17a on the bracket being provided with holes 20 to receive a pin 19 coacting with an adjustable stop 9a to give angular adjustment in the same manner as that about the shaft 2, clamping being effected by an arcuate slot 18 on the base 16 and studs on the bracket. The shaft 2 may have a conical bore 21 for receiving a work-supporting shaft or centre and the plate may have holes 22 or other means for attaching dogs or the work thereto. |
