GB430557A - Improvements in and relating to variable pitch propellers - Google Patents

Abstract

430,557. Screw propellers. LAFOND, G., 56, Rue Notre Dame de Lorette, Paris. Sept. 19, 1934, No. 26974. Convention date, Sept. 19, 1933. [Class 114] Variable-pitch screw propellers provided with mechanism for altering the pitch and with an independent locking device have two connecting members between the non-rotating part of the adjustment means and the part rotated with the propeller and these are engaged only when the pitch is being altered, but disengaged during normal operation. The blade roots carry pinions 4, 4<1> engaged by racks 5, 51 which are locked by means of segments 7, 7<1> which co-operate with members 9, 91. Normally, a spring-urged block 10 holds the parts 9, 91 and so locks the racks with the members 7. When it is desired to move the racks to change pitch the block 10 is slidden endwise, the members 9, 9<1> move outwardly under centrifugal force to release the racks. In an alternative form the racks are carried by bars 15 pivoted at 16, these bars being connected by links 17 on a member 19<1> capable of being slidden by a cam arm 20. Normally, the rack member is in engagement with the locking member 7. When it is desired to move the rack by means of the member 13, the handle 21 is turned and the links 17 tilt the rack bar free from the locking member. Instead of the blade roots having interengaging pinions those members may be made segmental so that the part engaging the racks has a different pitch radius from the interengaging parts. Where more than two blades are employed they are intercoupled with each other by gearing and each is provided with an adjustment mechanism.