Patent GB-624984-A (GB)
Title: Improvements in or relating to apparatus for dividing scientific glassware and the like
IPC: B44B3/00
Filed: 1947-07-21
Abstract: 624,984. Dividing-engines. GALLENKAlVIP & CO., Ltd., A., and DAVIES, S. J. July 21, 1947, No. 19503. [Class 97 (iii)] Apparatus for dividing scientific glassware and the like is provided with a commutator adapted to be rotated by the means rotating the glassware and having a conductor strip or strips thereon equivalent to the lengths of the graduations required and serving when contacted by a brush or brushes to move the scribing device into the marking position and means to control the operation of the brushes so that a predetermined sequence of graduations of predetermined lengths may be marked on the glassware in succession. The glassware to be graduated is mounted between a chuck 7, Fig. 2, and an adjustable support 8, and may be supported intermediate its ends and is rotated by an electric motor 2 through belt drive 3, main-shaft 4 and one to two gearing 5, 6. The gear 5 is provided with a driving plate and pin 11 of a Maltese cross transmission which serves to rotate a lead screw 13 mounted in bearings 14 once for each alternate revolution of the glassware. A split nut 20 is mounted on the lead screw 13, the lower half being threaded and the upper half being normally urged by spring means into driving engagement with the screw 13. The upper half of the nut has a straight edge 24 adapted to engage a roller 31 in the lower of two slots provided in a rocker bar 25, pivoted at 27, the upper slot of which contains a roller 30 engaging a straight edge 32 carried by the slide bar 33 on which the scribing device is mounted. By adjusting the position of the rollers by means of the threaded screws 34, the amount of movement transmitted to the straight edge 32 and hence to the scribing device 15 for a given movement of the lead screw 13 may be varied from an amount equivalent to one half the movement of the lead screw to an amount double that of the screw. The slide-bar 33 comprises two dovetail-shaped members, the lower slidably engaging the supports 34 and the upper bearing the scribing device 15 which may be adjusted thereto by fine adjustment means 39 and clamped by a clamping screw 38. A flexible cord attached to the lower surface of the slide bar 33 at the end thereof passes over a pulley and carries a weight to maintain the rollers 30, 31 in engagement with their respective straight edges 32, 24 to prevent any lost motion. The scribing device 15 comprises a scribing point 42 extending downwardly from one arm 44 of a bell-crank lever pivotally mounted on the carriage 37, the vertical arm of the bell-crank being bifurcated, one leg 46 having a return spring 47 and the other leg 48 being provided with an adjustable stop 49 for adjusting the return of the scriber point to its inoperative position. The horizontal arm 44 serves as the armature of an electromagnet 45 which when energized moves the scriber into marking engagement with the glassware. Current is fed to the electromagnet 45 by one of the contactor bars 51 from a commutator device 52 which has a dead segment 56, three segments side by side of different lengths 57a, 57b, 57c corresponding to a short medium and long graduation and a return segment 57d. Three spring strips 58a, 58b, 58c each carrying a brush 59, Fig. 4, and a cam follower 62 are formed in one integral member and in operation bear against the appropriate commutator segment 57a, 57b, 57c. Current is fed to the commutator by a strip 60 which is provided with a brush contacting the segment 57d. A cam pack 63 is mounted beneath the commutator 52 and comprises three cams, one for each strip 58, and a tentooth wheel which is adapted to be engaged by a peg 65 which rotates with the commutator 52 and thus rotates the cam pack 63 one step for each rotation of the commutator which is itself rotated by the main-shaft 4. The cam pack 63 has two flat surfaces 66 co-operating with the followers 62 on the strips 58b and 58c so that when peg 65 moves a flat 66 into contact with the appropriate follower 62 the brush 59 on that strip closes the contacts of the electromagnet 45 for a time interval corresponding to a medium graduation in the case of strip 58b and to a long graduation for 58c, profiled portions 67 on the cam pack 63 keeping the strip 58a out of contact with its segment 57a during such graduations. In the remaining eight positions of the cam pack strips 58b and 58c are kept out of engagement and strip 57a engages segment 58a to mark short graduations. The dead segment 56 extends round half the circumference of the commutator so that no marking current is supplied to the scriber 15 during its movement to a fresh marking position. The split nut 20 is provided with an electrical contact adapted to engage an adjustable contact mounted along a graduated scale running parallel to the lead screw, the contacts serving to operate a magnetically actuated brake member 68 when they engage at the end of a series of markings.