Patent GB-190317069-A (GB)
Title: Improvements in Autographic or Facsimile Telegraphs, applicable also for Curve Tracing.
Inventor: ROSSMAN GRANT BEEBE
Filed: 1903-08-05
Granted: 1904-06-28
Abstract: 17,069. Rossman, G. B. Aug. 5. Curves, figures, &c., plotting and reproducing. - Relates primarily to telegraphic apparatus adapted for reproducing at a distance, sketches, drawings, maps, &c., the receiving- instrument being, however, capable of use independently 148 as a curve tracer. The receiving-instrument comprises a tracing pen or pencil 6, Fig. 5, moving over a fixed paper-holding table and adapted to be given varying velocities in two directions at.rightangles, the resultant of which is traced on the paper and represents the direction signalled through the line from the transmitting - instrument. The penholder is pivoted at 3<a>, and can be raised from the paper by means of a wire 270, passing through an eyelet at the lower end of a rod 273 which also carries the armature 275 of an electromagnet 274. When the electromagnet 274 is energized, the effective length of the wire 270 is diminished, and the penholder is raised. The penholder is carried by a rod 9 movable longitudinally in the sleeve 8 by means of a wire 45, which is secured at both ends to the rod 9 and passes round a drum 49 on the shaft of the sprocket-wheel 50<a>. The variable angular velocity in one or other direction of the sprocketwheel therefore gives the penholder a corresponding radial velocity, which combines with a velocity at right angles due to the rotation of the support 25 on its bearings 22, to produce the resultant velocity of the penholder. The rotary movement of the holder 25 is produced by giving a certain angular velocity to a shaft bearing a pulley over which passes the band 31, Fig. 6, which is secured at both ends to the segment 30 by means of springs 33. The ratio of the angular velocities of the two controlling- shafts determines therefore the direction in which the penholder moves. Fig. 4 shows in plan the mechanism employed for giving the required angular velocities to the two shafts. An electric motor or other prime mover drives a flexible shaft 60 at constant velocity by means of a belt 56 and pulley 57. The shaft 60 drives a shaft 73, Fig. 13, through gearing 97, 98, and transmits the motion to a spherical segment 72 which drives a cylinder 71 by frictional contact, being clutched to it by magnetic attraction due to solenoids contained within the casings 106. In the position shown in Fig. 4, no velocity is transmitted to the cylinder 71, the velocity transmitted depending on the angle made by the sleeve 88 and shaft 73, in one or other direction, with the cylinder. This angle is determined by the longitudinal movements of a bar 90 which slides in boxes 91, the whole constituting a variable-speed device, designated A. The drum 72 is carried on a shaft which is extended in both directions in the form of two flexible shafts 62, 63 which drive the two variable-speed devices B, C, of which, in Fig. 4, the first is shown as transmitting zero velocity to its cylinder 71 while the second is transmitting maximum velocity, the bar 90 of the device C being at its limit of traverse in one direction and the shaft 88 at its maximum inclination. The two bars 90 of the devices B, C are actuated by cranks 107, 108 set at right angles on a controlling-shaft 64 extending from end to end of the machine. Any angular movement of the shaft 64 is therefore resolved into two components at right-angles represented by movements of the bars 90, and corresponding component velocities are given to the cylinder 71 of the devices B, C. The device A controls the absolute magnitudes of the velocities but not their ratio. The shaft of the cylinder 71 of the device B is extended, and carries the cylinder of a fourth variable-speed device D. Of the two controlling-shafts of the pen-holding device already referred to, that which effects the swinging movement is actuated through the sprocket-chain 42 from the variable-speed device B through the device D, and that which gives the radial movement to the penholder is driven from the device C through the sprocket-chain 52. The angular movement of the shaft 64, resolved as already described into two component velocities, therefore appears again as a resultant direction in the movement of the penholder. The device D is introduced merely for the purpose of compensating for the varying lengths of the reciprocable pen-arm, which would otherwise affect one of the component velocities given to the pen. It is controlled by means of a lever 296 pivoted at 299 and actuated by means of a worm on the shaft of the device C, which engages with a nut 297. The devices for giving to the controlling-shaft 64 the angular position which determines the direction of movement of the penholder, are of the following character :- A shaft 112, Fig. 18, driven at constant speed from the motor, drives bevel gears 118 in opposite directions. The gears 118 are in frictional contact with gears 123, 1@ which mesh with the outer members 128, 136 of a differential gear. The planetary member 132 does not communicate motion directly to the shaft 64, but through the medium of a second differential gear. The gears 128, 136 mesh with gears 147 which are under the control of escapement wheels 148, and it is only when one or other of these escapement wheels is released that a change in the angular position of the shaft 64 is effected. In other words, the penholder continues to move in a given direction until some alteration is signalled from the distant station, so as to cause the shaft 64 to take up a new position. Two electromagnets are provided in connection with each escapement wheel. The one acts on the armature 155 and rocks the lever 150 on the pivots 160, thus permitting the escapement wheel to advance one step. The other acts on the armature 165 and rocks the whole device about the pivot 164, thus withdrawing both escapement dogs from the wheel, and freeing it entirely. Under these conditions, the shaft 64 continues to rotate until arrested by a suitable stop, its direction of rotation depending upon which electromagnet was energized. This device is employed for bringing a number of instruments on the same line-wire into unison. The variablespeed device A, Fig. 4, is under the control of differential gear and escapement mechanism of the same general character as that shown in Fig. 18, four electromagnets being used to give positive and negative movements, step by step or continuous, as already described. By controlling the device A, the penholder can be reversed in direction or brought to rest, without altering the angular position of the controlling-shaft 64. By mechanically controlling the shaft 64 by hand or otherwise, the receiving-instrument can be used for tracing ellipses, harmonic curves, &c.