US2437810A

US2437810A - Variable pitch fan blade assembly

Info

Publication number: US2437810A
Application number: US564278A
Authority: US
Inventors: Samuel C Earley; Norman B Earley; Elmore J Sanders; Willard C Skareen; Ray L Davies; Joseph A Hughes
Original assignee: Evans Products Co
Current assignee: Evans Products Co
Priority date: 1944-11-20
Filing date: 1944-11-20
Publication date: 1948-03-16
Anticipated expiration: 1965-03-16

Description

March 16, 1948.

. S. C. EARLEY EI'AL VARIABLE PITCH FAN BLADE ASSEMBLY Filed, Nov. 20, 1944 2 Sheets-Sheet 2 IHI ' ELMORE J. SHNDER3 ayahalu 41am;

Patented Mar. 16, 1948 UNITED STATES PATENT F 2,437,810 F ICE 2,437,810 VARIABLE rrron FAN BLADE ASSEMBLY Samuel C. Eariey, Norman B. Earley, Elmore J. Sanders, Willard C. Skareen, Ray L. Davies, and Joseph A. Hughes, Toledo, Ohio, assignors, by mesne assignments, to Evans Products Company, Detroit, Mich., a corporation of Delaware Application November 20, 1944, Serial No..564,278

4 Claims. (01. 170-163) 1 1 This invention relates to variable pitch fans of the type used in connection with the cooling system of an internal combustion engine employed either on vehicles or in stationary installations for the purpose of varying the fan blade pitch in accordance with the requirements of service.

An object is to produce a variable pitch fan blade assembly of the above character having the new and improved features of construction, arrangement and operation hereinafter described, to the end that the structure can be readily and conveniently assembled and disassembled, can be manufactured emciently and economically, and can be maintained emciently in operation.

For purposes of illustration but not of limitation an embodiment of the invention is shown in the accompanying drawings, in which Figure l is a fragmentary side elevation, partly diagrammatic of the variable pitch fan assembly installed on an internal combustion engine in connection with engine cooling system;

Figure 2 is an enlarged vertical sectional elevation of the variable pitch fan blade assembly, showing in elevation an operating thermostat; and

Figure 3 is a front end elevation of the fan blade assembly, parts being broken away to show the operating mechanism and certain of the fan blades being omitted.

The illustrated embodiment of the invention comprises an internal combustion engine E, which is provided with the usual cooling liquid jacket J and a liquid circulating pump P. The pump P draws liquid from the lower end of the radiator core B through a tube (not shown) to the Jacket from which it returns to the radiator tank T through a tube S. Manifestly, the above structure is conventional.

Leading from the pump P is a tube in, which extends to a thermostat housing ii, and a tube 52 extends from the housing to a portion of the cooling jacket in the region of the tube S. Thus it will be apparent that a portion of the cooling liquid is bypassed through the thermostat housing ii so that the latter is supplied with liquid substantially of the temperature of that drawn from the radiator core R. The thermostat housing ii is fixed to the front end of the engine and mounted for rotational movement directly in front of the housing ii is a variable pitch fan blade assembly, generally indicated at A. The assembly A includes a hub it, on which belt sheaves i i are integrally formed, the hub being suitably mounted for rotation, although the detail structure of the mounting is not shown since it forms no part of the present invention. Reference is hereby made to the patent to Dewey 2,225,209

2 dated December 7, 1940, wherein one form of mounting is shown and described.

At the forward end of the hub i3 is an attaching flange l5, to which a fan blade unit B is rigidly secured by a series of bolts lSa. Forming a part of the unit B is a plurality of fan blades I6, which, as will hereinafter appear, are mounted for turning movements in response to changes in the temperature of cooling liquid.

Suitably mounted within the housing It in thermal contact with the cooling liquid therein is a thermostat I 1 into which an actuating rod or shaft I8 is slidable. The structure of the thermostat forms no part of the present invention so that detail description and illustration thereof is not considered necessary. Suffice it to say that as the temperature of the cooling liquid increases above a predetermined degree, the shaft I8 is forced inwardly or to the left of Figure 2 and is returned or moved to the right by a coil spring l9 as the temperature of the liquid drops. Thus the fan blades operate to draw or blow air through the radiator R in accordanc with temperature conditions prevailing in the cooling liquid, as will be readily understood by those skilled in the art. Various forms of thermostats may be employed for the purpose, for example, the well known bellows or Sylphontype thermostat may be used to advantage.

The outer end of the shaft i8 is screw threaded to receive a flanged sleeve 20 and having a press fit thereon is an antifriction thrust bearing 2|. A nut 22 on the end of the shaft is secures the sleeve 20 in place. The outer race of the bearing unit 2| is pressed into an actuating sleeve 23, the inner side of which is cupped to provide a lubricant reservoir and the outer side of which is cupped to provide a seat for the coneshaped helical spring IS. The smaller end of the spring i9 bears against a cover plate 24, which is held in place by the bolts Ilia and screws 25 against an outer hub section 26.

The outer hub or housing section 26 and the inner hub or housing section 21 are similarly formed and each comprises an annulus having mating socketed portions 28 for the fan blade mountings, the same being arranged in equidistantly spaced relation. The number of blades may vary but in the form illustrated, provision is made for six blades. Intermediate the socketed portions are web portions 29, through which the bolts iiia pass. Peripheral flange portions 30 on each hub section receive bolts 3 I, thereby securely to fasten the sections together. It will be apparent that the actuating sleeve 23 fits freely within the central opening provided by the

hub sections

26 and 21 so that it can reciprocate axially therein in response to the thermally actuated shaft l8 and the coil spring l9. Such reciprocal movement imparts rotary or turning movements simultaneously to the several fan blades I3. In this instance the actuating sleeve is formed with a plurality of rectangular grooves 32, one being provided for each fan blade and the same being disposed in planes at right angles to the axis and the direction of movement of the sleeve 23 and being open at the outer or peripheral side. Mounted within each groove 32 is an elongate block or shoe 33, which has a snug fit therein and has its outer surface approximately fiush with the adjacent peripheral surface of the sleeve 23. It should be observed that the outer surface of the sleeve 23 is provided with a series of flat surfaces, one for each fan blade, and arranged in parallel relation to the bottom walls of the grooves 32, respectively.

The socketed portions 28 in the

hub sections

26 and 21 each includes an inner cylindrical socket 28a and an outer cylindrical socket 28b, which is of considerably greater diameter. Mounted within the socket 28a for rotary movements is an annular block or disc 34, which has a press fit concentrically on a reduced pin-like end portion 35 of the fan blade shaft. A set screw 33 in the disc 34 engages the shaft portion 35 to assist in preventing relative rotation. Having a press fit in the disc 34 at one side or eccentrically thereof is a pin 31, which depends beyond the lower side thereof and extends relatively loosely into an opening in the subjacent actuating shoe 33 so that horizontal movement of the shoe 33 along with the sleeve 23 imparts rotary motion to the fan blade shaft.

Arranged directly above the shaft portion 35 i a screw threaded shaft portion 38, in which a jack nut 33 is mounted. The nut 39 may be turned to force the disc 34 from the shaft in the event of damage or breakage of the pin 31, it being understood that the set screw 36 is first loosened.

Abutting against the upper side of the nut 39 is an antifriction bearing unit 40, which is mounted on a cylindrical shaft portion 4| of slightly greater diameter than the screw threaded shaft portion 38. It will be evident that the nut 39 not only serves to retain the bearing unit 40 in place but also to provide a jack screw as above explained. The outer race .of the bearing unit 49 fits within a sleeve 42, which has an outwardly extending flange 43 at the lower end fitting in an annular groove 44 in the hub sections. The sleeve 42 is mounted within the outer cylindrical socket 28b. At the upper end of the sleeve 42 is an inwardly extending flange 45, which fits over the upper end of the bearing unit 40 in abutting relation to an annular collar 46 of the fan blade shaft. The collar 46 is integral with a fan blade supporting bracket 41 to which the fan blade l6 is secured by rivets 48 substantially as shown.

In operation it will be understood that movement of the shaft I8 in response to temperature variations is transmitted to the sleeve 23 which through the shoe 33 and eccentric pin 31 rocks the blade I6 in one direction or the other depending upon the direction of longitudinal movement of the shaft. Thus feathering of the blade is accomplished in accordance with the temperature of the cooling liquid circulating through the jacket enclosing the engine cylinders. of course, it will be manifest that although a single fan blade has been described, identical mounting is provided for each of the other blades, so that the pitch of all blades are conjointly varied.

Adequate lubrication is afforded to the assembly, because, as above pointed out a lubricant chamber is provided between the

hub sections

26 and 21, so that all moving parts are kept lubri- 4 cated at all times. In the event that the lubricant builds up pressure or trapped air within the chamber creates undesirable pressure, the same is automatically relieved by a spring tensioned relief valve 49 in the cover plate 24, which closes as soon' as the pressure is relieved.

Numerous changes in details of construction, arrangement, operation and choice of materials may be effected without departing from the spirit of the invention especially as defined in the appended claims.

What we claim is:

1. A variable pitch fan assembly comprising a pair of abutting hub sections having a central apertured portion, a plurality of fan blades mounted for rotary movement in said hub sections and including fan blade supporting stub shafts extending radially between said sections. bearing means for the respective stub shafts mounted between and supported by said hub sections, a disc fixed to the end portion of each of said stub shafts, a pin disposed parallel to and eccentric with said stub shaft, carried by the respective disc and projecting inwardly therefrom, a sleeve disposed in said apertured hub portion for axial movement, grooves in the peripheral portion of said sleeve arranged at right angles to the axis thereof and extending at right angles to said stub shafts, one groove being provided for each pin, a block fitting in each groove having a bearing socket for the adjacent pin, and means for axially .moving said sleeve.

2. A variable pitch fan assembly comprising a pair of abutting hub sections having a central aperture and a plurality of spaced radially disposed shaft receiving sockets, a plurality of fan blades mounted for rotary movement in said hub sections and each having a stub shaft extending into one of said sockets, an antifriction bearing for each shaft mounted in the outer portion of the respectivesocket, a disc pressed on to the inner portion of each shaft, an eccentric pin carried by each disc and projecting inwardly therefrom, a screw threaded portion on each shaft intermediate each disc and antifriction bearing, a nut on each screw threaded portion adapted to serve as a jack to remove said disc, an actuating sleeve in said hub aperture having a plurality of flat peripheral portions, a plurality of grooves rectangular in cross-section formed in the peripheral portions of said sleeve arranged at right angles to the axis thereof and extending at right angles to said stub shaft, one groove being provided for each pin, a rectangular block snugly fitting in each groove having a bearing for the adjacent pin, and means for imparting axial movement to said sleeve.

3. A variable pitch fan assembly as claimed in claim 2, which comprises sleeves disposed within said sockets respectively and providing mountings for said antifriction bearings, said hub sections having internal grooves, and outwardly extending flanges on said sleeves engaging in said grooves respectively.

4. A variable pitch fan assembly comprising a pair of abutting hub sections having a central apertured portion. a plurality of fan blades, means for mounting said fan blades for rotary movement in said hub sections, said means including fan blade supporting stub shafts extending radially between said sections, bearing means for the respective stub shafts mounted between and supported by said hub sections, a pin carried by and mounted eccentrically of the inner portion of each stub shaft. a concave-convex sleeve viding a seat for the other end of said spring, the

concave face of the sleeve providing a lubricant reservoir, and means for imparting axial movement to said sleeve.

SAMUEL C. EARLEY. NORMAN B. EARLEY. ELMORE J. SANDERS. WILLARD C. SKAREEN. RAY L. DAVIES. JOSE'PH A. HUGHES.

REFERENCES CITED The following references are of record in the 5 file of this patent:

UNITED STATES PATENTS Number Number Name Date Johansson Jan. 27, 1903 Brown Jan. 16, 1906 Kuleck Oct. 8, 1929 Squires July 16, 1935 Dewey Dec. 17, 1940 Roby 'Apr. 28, 1942 FOREIGN PATENTS Country Date France June 16, 1933 (Addition to 722,641)