US2257976A - Variable pitch propeller - Google Patents

Description

' Oct. 7, 1941. C MOQRMAN 2,257,976

' VARIVABLE PITCH PROPELLER Filed Nov. 2, 1938 H15 ATTORNEY.

Patented Oct. 7, 1941 2.257.976 VARIABLE rrrcn PROPEILER v Charles L. Moor-man, Blue Island, Ill. Application November 2,1938, Serial No. 238,304

1 Claim.

This invention relates to improvements in air circulating means for general application and of particular utility in connection with refrigerator cars, an important object being the provision of a variable pitch blower or fan which, in its preferred embodiment, is adapted for unidirectional movement of air regardless of the direction of rotation of the fan structure.

Viewed from another aspect, it is an object of v the invention to provide air circulating means of general application and particularly suited for use in refrigerator cars, wherein there is provided a fan having blades mounted on a hub portion for movement to change the pitch of the blades, and means for automatically pivoting the blades in one or another direction depending upon the direction of rotation of the fan structure or hub thereof, together with power take-off means coacting with the wheels of the refrigerator car to drive the fan, the fan blades being pitched in such manner that they will drive air in one direction only, regardless of the direction of rotation of the driving shaft or hub portion thereof, so that it is immaterial in which direction the car moves.

A further and more particular object is the provision of a variable pitch propeller or blower device including a hub having pivoted blades and mechanism operated by movement of the hub in opposite directions to pivot the blades and change their relative pitch or face responsive to reversals in rotation of the hub structure.

Other objects and advantages characterizing the invention reside in certain details of construction, operation, and form of the parts of the illustrative embodiment hereinafter described in view of the annexed drawing, in which:

Fig. l is a vertical median section through the length of a refrigerator car;

Fig. 2 is a perspective view of the power takeoff mechanism;

Fig. 3 is an enlarged horizontal section through the friction drive wheel in the take-off mechanism shown in Fig. 2;

Fig. 4 is a section through the blower structure;

Fig. 5 is a plan view of the reversing mechapositions.

nism and hub structure of the blower, seen in the direction of line 55 of Fig. 4; while Fig. 6 is a. transverse section along line 6-5 of Fig. 5.

In one of its applications illustrated in Fig. 1, the invention includes a fan or blower I0 mounted at each end of a refrigerator car near the opening ll leading from the upper region of an ice bunker I2. The fan or blower i0 is of the preferred construction hereinafter to be de. scribed and includes a spindle or drive shaft which is operated through a suitable flexible drive shaft and cable means 13 having driving connection as at N (Fig. 2) with the shaft of a friction power take-off wheel l5 arranged for driving engagement with a wheel l6 of a car.

The take-off mechanism may be of the type shown in Fig. 2 or in either of my copending U. S. applications, Serial No. 190,202 or Serial No. 238,305.. In the arrangement of Fig. 2; the friction drive wheel I5 is provided with beveled peripheral edge portions H which cooperate with the wheel l6 and are especially adapted to remain in driving engagement with the wheel when the v trucks are turned on curved track sections. The spindle for the wheel i5 is journaled in the opposite arms 18 and I! of a trunnion bracket, the arms being joined by a bight portion 20 which lends rziigidity to the structure, as does the cross brace attached to theunder structure of the car adjacent the wheel I, as illustrated in Fig. 1. A sleeve 25 is secured to the trunnion arms for movement therewith and has a radial projection 26 which bears against a spring 21 seated at its opposite end on an extension 28 from bracket 23. An operating lever 29 is fulcrumed as at 30 on an attaching bracket 3| a so secured to the under structure of the car, t e inner end of the lever being pivoted as at 32 to an arm 33 securedto one of the trunnion arms. By grasping the handle portion 34 and moving the lever up and down, the trunnion structure may be raised and lowered relative to the wheel Hi to move the friction wheel l5 into and out of driving engagement therewith. A locking bracket 35 also mounted on the underside of the car, provides slots in which the lever may be disposed to maintain the same in one or another of its pivoted This bracket also is provided with a sealing pin 36 removably mounted in spaced ears 31 in a position to block shifting of the lever from 'one slot to another, the pin 36 being apertured at The free ends of the trunnion arms, are pivoted on a shaft 22 secured in mounting .brackets Hand 24 which may be supportably set screw means 46 to one end |3a of the flexible driving connection. or cablell, the housing 44 having a threaded nipple 41 screwed into the trunnion arm I8 in a manner to force the collar 45 against the outer bearing race, so that the corresponding end of the spindle sleeve 48 is adequately joumaled, the opposite end of the sleeve extending through a bearing race 58 seated in a housing 5| secured in the opposite trunnion arm IS, the sleeve extending 'intothe hub of an auxiliary driving pulley 52 and terminating in a hub collar 53, the sleeve vbeing coupled with the pulley by a key 54. I An extremity 55 ofthe flexible driving shaft is connected for rotation with the sleeve by means of a plug 58 of fluxable metal moulded into the sleeve around the drive shaft, the hub collar 53 being 'of the split-ring type clamped on the sleeve by a screw 51, similarly to the arrangement 84' 8881 of Fig. 4..

A preferred form of the improved variable pitch fan or blower is illustrated in Fig. 4 and includes on the pins 82 by sleeves 65 and 68 secured in the hollow portion thereof by suitable means, such as spot welding or the like, and the journals or pivot sleeves 65 being positioned at a point between the trailing edge 84, and the leading edge 81 which corresponds to the bight portion of the folded blade sheet.

Means for automatically pivoting the blades responsive to rotation of the hub in opposite directions includes the provision of a radially extending pin in the bight portion of each blade near the hub 60, the lower ends of these pins projecting into slots H in a collar 12 mounted on the sleeve 6| and secured for rotation with the latter by a key 13.

Since the hub 88 floats on the spindle sleeve 8| while the collar 12 is rigid with the sleeve, it will be apparent that rotation of the collar in opposite directions will tend to move the several pins 10 correspondingly with a resultant pivoting of the several blades 'so that the latter willv be pitched in opposite directions relative to the direction of rotation of the hub and collar with the result that the curved leading edge 81 will always direction into a wide slot 14 in the collar 12,

which slot is wider in thedirection of rotation than the stopping projection 12a, so that there is -.a limited freedom of relative rotation between the collar I2 and the hub 88. Thus, when the collar 12 rotates in one direction, the side 14a of the wide slot I4 will move toward and bear against the projection 12a with a consequent pivoting of the blades 83 (Fig. 5), whereas areverse movement of the collar 12 will cause the opposite side 14b of the slot 14 to move toward and bear against the projection 12a, which results in pivoting the blades 83 in an opposite direction, as a result of the projection of the pins "in the several slots H and the relative inertia of the I'QtEtable or floating member 88.

To complete the fan structure, the spindle sleeve 8| is mounted in spaced bearing races 88 (Fig. 4) secured in a covered sleeve 8| which in turn is mounted by means of 'a set screw 82' on a collar 83 embracing the opposite end portion lib of the flexible cable IS. The driving extremity 55a of the flexible drive shaft extends into the borev of the sleeve 8| and has its end portion secured in a plug 84 by means such as the pin 85. The plug 84 and the spindle sleeve are joined for rotation together by a split collar 88 (Fig.5 also), the. split sides of which are drawn together by a T clamping bolt 81 which has a portion of its shank projected through a slot near the outer end of the sleeve 6| for disposition in a chamfered groove 88' in the plug 84 whereby the plug, the sleeve, and the split ring 88 are all keyed together for rotation by the end portion 55a of the flexible driving shaft. A suitable mounting flange 88 is extended from the housing sleeve 8|, whereby the fan structure generally indicated at l8 may be mounted as shown in Fig. 1.

The foregoing construction of the novel fan provides, what is termed for convenience, both a unidirectional and a variable pitch propeller, for it will be evident that the shape and arrangement of the blades as particularly described in conjunction with Figs. 4 and 5, is such that regardless of which direction the blades are moved, the air will always be "grabbed or seized along the curved edges 81 at the rear of the blades and deflected from the forward edges 8.4, this arrangement being of particular advantage in the application of the fan in refrigerator cars, since the latter are likely at anytime to have their direction of movement changed.

It will be understood that the blades 83 may themselves be pitched relative to coordinates therethrough, and the pivotal movement of the several blades by the automatic means'heretofore described will vary the pitch of the propeller depending upon the direction in which the blades are moved. i

The objects and-advantages of the invention may be realized by other forms of construction than that specifically detailed in the illustrative embodiment, and it will be understood that the invention as defined in the appended claim is intended to include all equivalent forms, modifications, and applications of the illustrative arrangement.

Having thus described my invention, what I claim as new and desire to protect by Letters Patent is:-

A fan including a driving shaft, a driving hub member mounted for rotation with said shaft, a driven hub member arranged to float on said shaft, one of said hub members having a slot of predetermined length extending in the direction of rotation thereof and the remaining hub member having a projection extending into said slot same for joint rotation thereof, a plurality ofpivot members mounted on one of said hub members to extend ina direction at an angle to the axis of rotation thereof, a fan blade pivotally mounted for adjusting movement on each or said hub members being displaced as aforesaid as a pivot members, each or said blades having an result or the inertia oi. said floating hub member eccentricaliy positioned finger projected into slot consequent upon a change in the direction of means provided in the remaining hub member .rotation of the same with drivinghub whereby relative rotational displacement or said 5 Y member. hub members will eflect adlusting pivotal move- CHARLES L. MOOBMAN. ment oil said blades in opposite directions, said

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