Patent GB-951841-A (GB)
Title: A graphic communication recorder
IPC: G08C21/00
Filed: 1962-01-17
Abstract: 951,841. Recording apparatus; reservoir pens. VICTOR COMPTOMETER CORPORATION. Jan. 17, 1962 [Feb. 2, 1961], No. 1670/62. Heading B6P. An ink supply system for a graphic communication recorder, Fig. 1, comprises an ink reservoir means 24 for storing a supply of ink under a substantially constant static head, a conduit connecting the reservoir to a recording pen 10, and valve means 31, interposed in the conduit between the reservoir and the pen for closing the conduit whenever the pen is moved to a non-recording position. The recorder includes means for moving the pen 10 omnidirectionally across the recording surface of a platen 12 and comprises a linkage 16 connected to a pen support arm 11, actuated by a pair of drive motors 17, 18. An electrically actuated device or solenoid 19 together with a wire 21 acts as a pen contact device. Control of the motors 17, 18 and the solenoid 19 is from " receiver circuits " 22 receiving data from a transmitter. The valve means 31 includes a turncock valve 32, Fig. 5, wherein the rotatable plug 34 is mechanically connected to a solenoid actuator 36 by a drive linkage 35. A spring 37 biases the valve 32 in a closed position. A relay 38 in the energizing circuit of the solenoid actuator 36, is in series with the solenoid 19. A signal to lower the pen 10.will simultaneously open the valve 32. In the conduit between the valve 32 and the pen 10 is a length of corrosionresistant metal (e.g. 300-series stainless steel) tubing 41 providing a fixed resistance conduit limiting the flow of ink to a known maximum value. Between the tubing 41 and the valve 32 is a variable resistance device 42, manually variable or automatically variable by a " valve actuator " in series with the motor 17 providing the vertical movement of the pen. This device 42 minimizes or eliminates the effects of acceleration and vertical displacement of the pen upon the supply of ink to the pen when the recorder has a vertically orientated writing surface 13. Manual adjustment of device 42 is sufficient when the writing surface is horizontal. The reservoir 24 comprises a storage chamber 25 in the form of a bellows, and a weight 26 mounted on the bellows, providing the desired constant static head, through which the conduit 27 passes. Other constant static head systems may be used (not illustrated) such as a compound constant-stress spring system of conventional design or a vented reservoir of relatively large area and shallow depth located well above the top of the platen 12. Two embodiments of pen 10 are shown, Figs. 3 and 4, of corrosion resistant metal tubing such as 302 stainless steel. The nib 58, Fig. 3, has a suitable coating of hydrophobic material, such as a silicone, to prevent ink flowing back along the external surface of the pen. The nib 58 may also be encased in a short length of thin fluorinated hydrocarbon resin. A solenoid actuated normally closed needle valve of a known kind may be substituted for the valve 32, which affords a relatively small " downstream " displacement on closing and opening in order to avoid flooding of the recording surface.