| 摘要 |
1,126,959. Template followers. NASSOVIA WERKZEUGMASCHINENFABRIK G. m. b. H. May 27, 1966 [May 28, 19651, No.23951/66. Heading G3N. [Also in Division B3] A tracer assembly for a copying machine tool comprises a tracer, a control head having a rotary member and a stationary member rigidly mounted on the tracer, the rotary member being rotatable within or around the stationary member about an axis perpendicular to the selected plane in which the tracer is intended to follow a pattern, biassing means urging the stationary member off centre relative to the rotatable member, drive means connected to the rotatable member, and switch means having three positions controlling the drive means for left hand and right hand and null rotation, the switch means taking up one or other of these positions in dependence upon the direction of off centredness of the stationary member relative to the instantaneous direction of feed movement of the tracer. A tracer 3, 4 in a copy milling machine is mounted by forked levers 2, 2' so as to be displaceable bodily i.e. parallel to its own axis in three co-ordinate directions such displacement being sensed by hydraulic valves 5, 6, 7 and used to effect corresponding feed movements of the tool and tracer. A ball 13 supported from the upper end of the tracer is surrounded by a rotatable control head 14 which has three electrical contact rollers 17,18,19 and a pressure member 23, 24, 25 adapted to press the ball 13 into an eccentric position relative to the head against one or more of the contact rollers 17, 18, 19. The electrical connections to the rollers 17,18,19 are such that the control head, which may be driven clockwise or anticlockwise by a motor 16, remains stationary when the ball 13 is in contact with rollers 18,17 or 18,19, this condition is reached when the control head is in a position such that the pressure member 23, 24, 25 exerts a control force on the ball 13 and thereby on the tracer directed at some desired angle e.g. 30 degrees, to the tangent to the tracer at the point of contact with the pattern. The control head 14 is supported in a housing 9, 10 which may be adjusted angularly about the tracer axis and about an axis perpendicular thereto, the particular setting of the housing determining the scanning plane for the tracer. When a change in direction of the pattern contour is reached the tracer is deflected so that the ball 13 moves to lose contact with one or more of the contact rollers 17, 18, 19 which results in rotation of the head 14 in an appropriate direction to restore contact and to restore the angle between the line of force under which the tracer is urged into contact with the pattern and the tangent at the point of contact to the desired value. In modifications Fig, 3, 4, 7, 8, (not shown) the rollers are replaced by arcuate contact segments while the measuring ball and head may be replaced by a ring member with a measuring disc member located within it and carrying the contact rollers or segments, Figs. 5, 6, 7, 8, (not shown). |
