US 1504769 A
Description (OCR text may contain errors)
r Aug. 12 1924. 1,504,159 H. LEITNER MECHANISM FOR VARYING 'I HE PITCH 0F SCREW PROPELLERS Filed April 21 1924 fm/entgr 7 MM law-M,
Patented Aug. l2, 1924.
UNITED STATES 1,504,769 PATENT OFFICE.
HENRY LEJ ITNER, OF LONDON, ENGLAND.
MECHANISM FOR VABYING THEPITGH 01? SCREW PROPELLERS.
Application filed April 21, 1924. Serial No. 708,095.
on each blade stem in the form of a worm-- wheel concentric with the stem and engaging a worm, which is geared by means, such as spur-gearing, to a common wheel which I term a master-wheel. Every blade is thus geared to this master-wheel so that if this wheel be rotated in either direction, each blade will rotated on its axis through a certain angle, thereby varying the pitch of the whole propeller. Means are also described in the said specification whereby the master-wheel can be rotated at will.
Now, the object of this invention is to provide improved means for rotating the master-wheel either at the will of the operator, or automaticall or both, and to this end I proceed as fol ows, that is to say, con centric with the master-wheel I provide a spur-wheel which may be locked to, or geared to, or otherwise suitably held to the said master-wheel and meshin with the teeth of this spur-wheel I provi e a toothed quadrant fulcrumed to the hub of the prowheel engaging with it, which in turn will rotate the master-wheel and thereby the propeller bladesthrough the worm-gearing.
Suitable mechanism for swinging the quadrant comprises a rail or roller fixed to some stationary. art of the engine or machine carrying tip latter, but movable so that as the prope ler revolves, the rail or roller contacts with some portion of the quadrant and rocks it on. its fulcrum to alter the pitch of the propeller blades. 'Anto be rotated b other rail or roller applied in the op ositc direction will turn the propeller bla es in the reverse direction. These rails or rollers may be moved by suitable means by hand.
To enable the invention to be fully understood I will describe it by reference to the accompanying drawing, in which:
Figure 1 is an elevation of a portion of the hub of a two-bladed screw-propeller, the blades of which are variable for pitch, havmg my improvements applied thereto.
Figure 2 is a sectional View at right angles to Figure 1 and Figure 3 is a plan with certain parts removed.
a is'the hub of the propeller and b, b are the cylindrical stems of the blades which are located and turn in the bearings c, c. d, at are the worm-wheels on the said stems and e, a, are the worms gearing therewith and rotatable by spur-wheelsor pinions f, f engaging the common or master spur-wheel g.
h is the spur-wheel concentric with the master-wheel g and i isthe quadrant the teeth of which mesh with those of the wheel it, so that when the said quadrant is rocked on its fulcrum it will effect the rotation of the said wheel h and consequently rotate the master-wheel g to efi'ect the equal rotation of both propeller blades to adjust the pitch angle.
j is one of the rollers whereby the quadrant i is rocked on its fulcrum, the said roller being moved or interposed in the path of another roller is carried on the said quadrant so as to contact therewith and effect the required movement. This roller.
1 is shown as being carried by a screwed bolt Z which can be moved longitudinally by a nut m engaging therewith and adapted a rope or chain m controlled or move in any suitable manner by hand. For moving the uadrant in the opposite direction to that dii'ected by the roller is, another roller, not shown, similar to the roller 7' is employed which acts upon a second roller n on the quadrant, these two last mentioned rollers being in a different plane from that of the rollers y", 70.
Although I- have described the wheel h as being concentric with the master-wheel 9 it may be geared thereto and, instead of the quadrant, I may employ a complete toothed wheel or a toothed rack of a shape in the nature of a cam.
the engine increases its speed the quadrant in engagement with the spur-wheel causes the latter to rotate by virtue of the increase of centrifugal force set up in the parts. The blades consequently being made to increase their pitch so as to offer more resist ance to rotation, and vice versa, thus governing the engine or propeller speed.- Such means may comprise a weight attached to one side of the quadrant and exerting a pull thereon by centrifugal action, a compression or like spring being arranged on the opposite side of the quadrant to return it to its normal position.
Although the invention has been described inconnection with two-bladed propellers it is to be understood that it may be 'appliedto propellers having three'or four blades.
1. Mechanism for Varying the pitch of screw propellers including a propeller hub, a master wheel, a spur-wheel connected to said master wheel, a toothed member in gear with said spur-wheel and pivoted to said propeller hub, and means interposed in the path of said toothed member as it is rotated by the propeller hub to cause said toothed member to rock on its pivot in either direction whereby the propeller blades are rotated around their axes. 2. Mechanism as claimed in claim 1, wherein said spur-wheel is mounted concentrically with said master wheel, and the toothed member is in theform of a quadrant.
3. Mechanism as claimed in claim 1 wherein said means for causing the toothed member to rock on its pivot, includes a stationary member and rollers on said toothed member adapted to contact with said stationary member.