Patent GB-515782-A (GB)
Title: Improvements in or relating to apparatus for detecting or detecting and preventing ice formation
IPC: B64D15/20
Filed: 1938-03-11
Abstract: 515,782. Windscreen wipers. GREEN, M. March 11, 1938, No. 7596. [Class 138 (i)] [Also in Groups XXXIII, X and XXVII] Apparatus for detecting and indicating and/or detecting and preventing ice-formation, for example, on aircraft or moving vehicles, comprises a detector member movable adjacent to a part or surface on which ice may form, and indicating and/or de-icing apparatus so associated with the detector member as to be operative when movement of the latter is impeded by ice-formation on the part or surface. The indicating and/or de-icing apparatus is usually operated by a movable member, which may be the part subjected to ice-formation, associated with the detector member or the drive for the same and normally maintained stationary by frictional or other means. Movement of the normally stationary member may operate electric contacts controlling directly, or through a relay, a warning 'lamp, a shutter controlling a supply of, hot air or gas, an electric heating element, or a pump or valve controlling a supply of anti-freezing liquid. The apparatus may be applied to windscreens, and the induction systems of carburetters, in which latter case means may be provided for increasing the temperature of the inlet air or supplying antifreezing solution to the induction pipe or carburetter. Alternatively, hot lubricating oil or exhaust gases may be supplied to a jacket surrounding the induction pipe or carburetter or an electric heating element in the jacket may be energized. In the form shown in Figs. 1 and 3, a vane 1 is rotatable adjacent a surface 3 subjected to ice-formation and is driven by a spindle 5 through a differential gear and a flexible member 4. The gear comprises a double pinion 6 eccentrically mounted on the spindle 5 and meshing with pinions 7 and 8 having different numbers of teeth: The pinion 7 is connected to the member 4 and the pinion 8 is provided with a recess engaged by a roller 9 carried by a spring pressed plunger 11. The plunger is provided with a sleeve 12 of insulating material which normally engages spring contacts 13 connected to terminals 15 carried by a plate 14 of insulating material. When the surface 3 is free of ice, the pinion 8 is maintained stationary, but when the movement of the vane 1 is impeded by ice the pinion 8 is moved to raise the plunger 11 and complete the circuit between the terminals 15..The completion of the circuit may cause operation of a warning lamp or bell and/or de-icing apparatus. As the pinion 8 rotates the 'plunger 9 drops into the recess once per revolution and thus causes intermittent operation of the signal. The flexible member 4 may be dispensed with and the clearance between the vane and surface may be adjusted. If the spindle 5 is driven by an electric motor, a flange 16 on the drive housing is connected to the motor casing. In the arrangement shown in Fig. 5, the pinion 8 is in mesh with the bevel gear 24 for driving a pump 17 for anti-freezing liquid or other mechanical de-icing apparatus, and is normally maintained stationary by the friction of the bevel gear and the force required to drive the pump. When a supply of anti-freezing liquid is available at an adequate pressure, the pinion 24 may control a valve. This arrangement may be applied to windscreens, in which case. the vane is constituted by the wiper blade and the spindle 5 is connected to the wiper driving mechanism. The anti-freezing liquid may be supplied to a channel in the wiper blade. The arrangement of Figs. 1 and 5 may be applied to the induction system of an internal combustion engine, in which case the vane 1 is mounted in a bend of the pipe and is connected by the flexible member 4 to a unit similar to that shown in Fig. 5. The pump 17 draws liquid from a tank and supplies it to the carburetter. In another form, Fig. 7, the part subjected to ice-formation is itself movable to operate indicating and/or de-icing apparatus. A vane 26 is carried by a shaft 27, rotatable in a sleeve 28 carrying a disc 29, and driven by cable 35. The sleeve 28 is rotatable in a housing 30 of insulating material .and carries dogs 31 engaging corresponding dogs on a second sleeve 32 carrying a disc 33 The disc 33 is provided with a pair of diametrically opposite recesses 34 which are lined with insulating material and are engaged by stationary spring pressed plungers 36 connected to terminal wires 38, 39. If ice forms on the disc 29, it is caused to rotate with the vane and the plungers 36 leave the recesses 34 and engage the conducting part of the disc to complete the circuit through the wires 38, 39. Instead of forming the housing 30 of insulating material, the plungers may be insulated from one another. The disc 33 may be replaced by a driving pinion for a pump 'for anti-freezing solution or other mechanical de-icing apparatus.