US2687182A - Propeller or fan blade - Google Patents

Description

J. c. HOGAN PROPELLER 0R FAN BLADE Aug. 24, 1954 2 Sheets-Sheet 1 Filed June 29, 1950 c/o/m C. Hogan INVENTOR.

A TTORNEYS g- 1954 J. c. HOGAN PROPELLER OR FAN BLADE 2 Sheets-Sheet 2 Filed June 29, 1950 (lo/7n C. Hogan INVENTOR. BY aim/tn 73. @ZM

A TTORNEYS Patented Aug. 24, 1954 UNITED STATEfi LtSLlZ T OFFICE Claims.

This invention relates to a fluid propeller, as a fan or a propeller for a vessel, the propeller having a support member connected to the hub with longitudinal axis bisected perpendicularly by the hub axis, and also having an interconnected and oppositely extending pair of blades connected in turn to each support member end so that the longitudinal axis of the support member bisects the longitudinal axis of the pair of blades.

It is an object of this invention to provide a propeller comprising two pairs of interconnected and oppositely extending blades spaced apart by a support member so that the longitudinal axis of the support member perpendicularly bisects the longitudinal axis of the pairs of blades, the support member longitudinal axis in turn being perpendicularly bisected by the longitudinal axis of the propeller hub.

It is also an object of this invention to provide a propeller of this class in which the leading blade of each pair of blades has a leading edge nearest the hub axis while the leading blade extends therefrom outwardly oppositely of the hub side to the trailing edge, the trailing blade of each pair of blades conversely having a leading edge farthest from the hub axis while the trailing blade extends therefrom outwardly oppositely of the hub side to the trailing edge.

It is still a further object of this invention to provide a propeller of this class having the 1eading edges of each blade substantially straight while the trailing edges are curved to substantially reduce the distance across the blades at their points of connection to the support member.

It is yet a further object of this invention to provide a propeller of this class in which the are at the end of each support member begins on the same side of the longitudinal axis of the support member as the leading edge of the trailing blade and extends across the axis to join the curved trailing edge of the leading blade.

It is still a further object of this invention to provide a propeller of this class which is adapted to direct fluid in a column along an axial extension of the propeller hub axis, the diameter of the column being substantially twice the radial distance from the hub to the blade point farthest therefrom.

It is also an object of this invention to provide a propeller of this class which does not propel fluid radially outward of the blades, but rather directs fluid radially inward and along the axial extension of the hub axis.

It is a further object of this invention to provide a propeller of this class which is adapted to reduce turbulence by curving the trailing edge of each blad to reduce the distance across the blade to a minimum adjacent the center support, thereby streamlining the fluid flow axially and radially inwardly.

It is still another object of this invention to provide a propeller of this class comprising pairs of interconnected and oppositely extending blades each pair being radially spaced from the hub axis by a radially extending support memher with longitudinal axis perpendicularly bisecting the longitudinal axis of the pair of blades connected to the end thereof.

It is still a further object of this invention to provide a propeller of this class adapted to deliver a greater horse power than a conventional- 1y designed propeller of the same diameter.

It is additionally an object of this invention to provide a propeller of this class having the leading blade of each pair of blades pitched to direct fluid axially away from the propeller while the force of such directed fluid creates suction to draw fluid from the hub or prime mover side of the propeller to follow the fluid thus axially directed.

It is yet another object of this invention to provide a propeller of this class having a trailing blade which is adapted to out into and direct axially fluid thus moved responsive to the suction created by the leading blade.

It is also a further object of this invention to provide a propeller of this class which has a hub element comprising the hub proper and a support member for the blades which are together of such reduced cross-sectional area as to provide a substantially surrounding area between the blades of each pair, and especially between the pairs of blades, as to provide a ventilated hub.

It is a further object of this invention to pro-- Vide a propeller of this class having blades pitched after an arrangement which will permit a substantial amount of fluid to be drawn from the prime mover side of the propeller through the ventilated hub area to follow centrally the fluid directed annularly therearound by the thrust of the blade surfaces.

Other and further objects will be apparent when the specification is considered in connection with the drawings in which:

Fig. l is a perspective view showing the configuration and direction of the fluid column directed by the propeller of this invention.

Fig. 2 is an elevation of the propeller.

Fig. 3 is a view of the propeller taken along line 3--3 of Fig. 2.

Fig. 4 is a view of the propeller taken along line ti-i of Fig. 2.

Fig. 5 is a diagrammatic view showing the path of fluid travel with relation to the leading blades.

Fig. 5 is a view taken along line 6--6 of Fig. 5 showing the path of fluid travel.

Fig. 7 is an additional diagrammatic view showing the path of fluid travel with relation to the trailing blades.

Fig. 8 is a view taken along line 88 of Fig. 7 to additionally illustrate the fluid flow.

The propeller i has a hub or axle 2 adapted, as by the slot 3, for connection to a prime mover, not shown. A support member 4 extends perpendicularly to the propeller axis centrally of the hub and is connected tothe hub at 5, and is bisected by the hub or propeller axis. A pair of blades 6 are connected to either end I of the support member 4.

These blades extend substantially oppositely of each other from the longitudinal axis of the support member and each pair 6 comprises a. leading blade 8 and a trailing blade 9. The leading blade 8 has a leading edge 1 I which is preferably straight, and a trailing edge l2 which is preferably of a curved contour. The terms leading and trailing edges are applicable when the propeller rotates in the direction of the arrow shown on the column of air in Fig. 1.

For purposes of definition the blades of each pair may be termed as comprising a primary blade and a secondary blade. As can best be seen I in Fig. 1 the leading edge ll of the leading blade 8 which may be termed the primary blade is connected to the support member nearer the hub side of the propeller and the propeller axis than the trailing edge !2, and the blade 8 slopes or is canted therefrom outwardly from the hub axis and in the direction toward the thrust side of the propeller. This thrust side of the propeller is obviously the side opposite the prime mover and the hub connection therefor.

On the other hand the trailing blade 9 which may be termed the secondary blade has a leading edge M which is connected to the support farther from the hub axis than the trailing edge l5, and which edge M is preferably straight. The trailing blade 9 extends from its leading edge 14 and is canted outwardly to the same angular degree from the plane of the support member 3 as the blade 8 in the direction oppositely of the hub side, or on the thrust side of the propeller,

substantially semicircular or arcuate edge 25 which merges with the blade leading edge tangent thereto. Such outer edge joins the curvature of the trailing edge to define a graceful, streamlined configuration. As shown in Figs. 5 and 6, as the leading blade 8 rotates, the leading edge It cuts into the fluid to be moved at an angle pitched from the hub side outwardly in the direction of thrust.

The fluid thus moves along the thrust face of the blade, as indicated by the dotted portions of the lines shown in Fig. 5 and as indicated by the lines of flow shown in Fig. 6. The rotation of the thrust surface of the blade against the fluid thus cut tends to move it radially inwardly as indicated by the flow lines to the rightof the blades shown uppermost in Fig. 1.

.As shown in Fig. 5, the fluid on the hub side of the leading blade, or on the side adjacent the prime mover, follows the pitch of the blade which extends in the thrust direction from the leading edge and passes radially inwardly and in the direction of thrust after it courses through the open space 26 between the leading blade 8 and trailing blade 9 of the pair of blades 6.

In Fig. 6, the arrows indicate the flow of the fluid off the thrust face of the leading blade 8. It should be noted that this fluid defines a column which has a diameter substantially equal to twice the distance from the hub axis to the point on the blade porion ll farthest therefrom. In other words a propeller designed after the theory of this invention thrusts outwardly an annulus of fluid defined in cross-section by the space between the inner and outer dotted circles shown in Fig. 5.

The fact that the large blade portion i7 contacts and directs the greatest amount of fluid while the smaller or reduced portion of the blade 18 contacts and directs a lesser amount of fluid, accounts to a substantial degree for the delivery of the annulus of fluid hereinabove described.

Fig. 7 shows the path of fluid with relation to the trailing blades. The leading blades direct the fluid radially inwardly and axially in the direction of thrust to substantially define an annular column. This can be visualized when one observes that the leading edge of each blade extends substantially in the plane of the support member and the plane of the blade extends outwardly therefrom on the opposite side of the support member plane from the hub or prime mover to the trailing edge. It can thus be seen that the blade on each end of the support ex tends at substantially the same angle from a radial plane perpendicular to the hub axis, and also extends on opposite sides of a plane through the longitudinal axis of the support and through the hub axis. The trailing blades thus cut into the fluid which is drawn by suction to flow from the prime mover side of the propeller, and this fluid moves as shown in relation to the upper blade in Fig. 8, across the thrust face of the trailing blade 9 from the leading. edge I4 outwardly to the trailing edge l5. This fluid follows the fluid directed by the leading blades to flow in the annular column. The fluid on the prime mover side of the trailing blade, as shown in the lower portion of Fig. '7 moves from the leading edge of the trailing blade in the direction of the leading edge I5 of this blade and axially into the annulus. Such fluid is not thrust, of course, but is drawn across the back face of this blade by the suction created by the flow of the fluid.

In addition to the fluid directed into the an- I nulus by the propeller blades, there is ,an additional central column of fluid which is drawn from the prime mover side by the suction of the fluid delivered to the annulus. A consideration of Figs. 5 and 7 shows the annular ring in dotted lines of a width designated by the line in Fig. 5 terminating in arrow heads at the outer and inner circular dotted lines. This is the width of the annular area into which the blades project the fluid outwardly to form an annular column. of fluid. The motion of this fluid draws by suction additional fluid from the prime mover side of the propeller. This fluid flows to some extent into the space 29 outwardly between the blades of each pair, but to a much greater extent into the space 2! between the leading blade of one pair and the trailing blade of the other pair of blades. Such fluid fills in the space within the annulus and completes the delivery of a substantially complete column of fluid.

A close consideration of the drawings will show how the spaces 28 and 2| are defined. Attention is directed specifically to Fig. 2. If a line along the substantially straight leading edge is of a secondary or trailing blade :3 is extended inwardly, and if a line along the generally straightdirection of the trailing edge 12 of the primary or leading blade 8 of the same pair of blades is also extended inwardly, these lines will converge toward the rotary axis and intersect at substantially the radial center line of the support member or radial arm i and at a point on such support member spaced a short distance from the axis of rotation. It is thus apparent that there is a substantially large angle of divergence between these two intersecting projection lines which define the space 23.

Also, a close consideration of the drawings, for instance, Fig. 2, shows that a line along the straighter portion or one projected in the general direction of the trailing edge if: of a trailing blade ii will be angularly related or out of parallel to thenext succeeding leading edge ll of a leading blade 8 of the co-operating pair of blades, and if two lines along the edges H and I5 are projected outwardly, they will converge away from the axis of rotation and intersect at a point spaced a considerable distance from the axis of rotation of the device. Furthermore, they form between them a small angle of divergence, and the angularly. related edges Ii and i5 have betweenthem the space 2|. By comparison, the point of intersection of the projected lines bounding the space 2! is remote and farther outward- .ly from the device axis than is the intersection of those two lines which bound the space 20, which latter point of intersection is close to the axis and on the support member 3.

The blades are skewed in relation to their travel direction, and the longitudinal axis or center line of each blade is offset in relation radially of the axis of rotation, such axis of each primary blade being offset or displaced counterclockwise and such axis or" each secondary blade being oifset or displaced clockwise. If a radial line is drawn from the rotary axis to a point of contact with the leading edge ii of a leading blade 8 and near or at its point of mergence with the outer edge of the blade, such leading edge l l is skewed or recedes at an angle to the radial line inwardly and backwardly, or away from the direction of rotation. .On the other hand, if a radial line is drawn from the rotary axis to a point of contact with the trailing edge It of a trailing blade 9, at its point of mergence with the outer edge of the blade, such trailing edge It is angularly skewed or extends inwardly and forwardly in the direction of rotation from such point of contact or mergence.

It should be noted that the curvature of the are between the blades of each pair at the locality of the support member end 1, begins on the trail ing blade side of the longitudinal axis of the support member at its point of convergence with the leading edge It and extends across this axis to merge into the trailing edge [2 of the leading blade 8.

This streamlined configuration between the blades of each pair results in a substantial reduction of the distance across the blade portion [8, as compared with the distance across the portion I1. This shape insures that the fluid impelled by the blades does not flow oil the ends of the blades but rather flows radially inwardly as well as outwardly in the direction of thrust. The innermost portion 18 of each blade, at its point of convergence with the support member 4, or optionally at its point of junction with the adjacent blade of the pair, is of such a reduced diameter that the fluid impelled by the thrust face of such portion I3 is drawn from the prime mover side of such portion i8 and is moved into the central column of fluid delivered with a minimum of turbulence.

This propeller constitutes a basic invention in the flow of fluids in that it solves the problem which the designers of vessels, as motor boats, have long endeavored to solve. Namely, this propeller insures the delivery of a forceful column of fluid behind the propeller, the axis of such column being an extension of the axis of the shaft on which the propeller is mounted. A column of this shape naturally obtains the greatest efliciency in propulsion in that the power delivered acts co-axially with the prime mover axis to move the vessel directly forward.

The principle of this invention may also be applied to fluid propeller elements, as fans, in which case the same theory acts to impel a gas, as a column of air, directly outward from the thrust face of the fan. As a consequence the gas or air delivered may be positively directed, with assurance, at the object at which the fan is directed.v

The use of this invention as a propeller for vessels and as a fan, does not constitute the extent of its usage but it is additionally adapted to any and all usages where it may be required to transfer a column of fluid, whether such fluid is liquid or gaseous.

It is pointed out that whereas the word suc- 4 tion has been used to describe the factor which draws fluid along to follow fluid directed into the annulus by the leading blades, and to describe a factor which draws fluid into the central column within the annulus, such word suction may have the eiiect low pressure area substituted therefor in the case of the use of this propeller in a liquid. On the other hand, the word Vacuum may be substituted for the word suction in the decription of the operation of this invention in a gas.

The form of the invention disclosed in the drawings is provided with a hub, but a hub of the construction shown is not an essential part of the invention, as any means for connection to the prime mover may be employed. As a matter of fact, it is possible to operate a pro peller which has no hub structure whatsoever but which has only a bore through the hub portion of the flat support member i, through which the shaft of the prime mover may be inserted.

In order to provide a balanced propeller or fan it is necessary that the blades should ent equal surface areas and conform to the rules of symmetry. Additionally, the propeller or fan should be so constructed that it is in both static and dynamic balance.

In the form of invention disclosed, the pairs of blades are shown spaced apart by a common support member bisected by the hub axis but the theory of this invention may be employed by using more than two pairs of adjoined blades, in which case each pair may be supported by a support member extending radially from the hub, such support members being preferably equally spaced about the hub periphery.

Broadly, this invention considers a novel propeller construction in which oppositely extending pairs of blades are connected to the end of a radially extending support member, the longitudinal axis of such member substantially bisecting the longitudinal axis of the pair of blades connected to the end thereof. In such invention the blades are so pitched that the leading edge of the leading blade of each pair is nearest the propeller axis and nearest the prime mover side of the propeller while the leading blade is pitched from its leading edge outwardly to the trailing edge and in the thrust direction. On the other hand the trailing blade of this invention has a trailing edge which is nearest the propeller hub or axis and this trailing blade extends from its trailing edge outwardly and in the direction of the prime mover to its leading edge.

What is claimed is:

l. A fluid propulsion device comprising, an axially extending member, a support extending transversely across said member and connected centrally thereto, a pair of blades connected to each end of said support, each pair comprising, a leading blade and a trailing blade, each blade being defined by successively adjoined edge portions comprising, a substantially straight leading edge extending outwardly from said sup port, a substantially semi-circular outer edge, and a concavely arcuate trailing edge returning to said support, the trailing edge of said lead-- ing blade and the leading edge of said trailing blade joining said supportiarther from said member than the leading edge of said leading blade and the trailing edge of said trailing blade, and on each blade the distance between the junction of said leading edge with said support and the junction of said trailing edge with said support being substantially less than the diameter of said semi-circular outer edge, said blades being pitched so that the trailing edges are outwardly of the leading edges in the direction of fluid flow.

2. A fluid propulsion device comprising, an axially extending member, a support extending transversely across said member and connected centrally thereto, a pair of blades connected to each end of said support, each pair comprising, a leading blade and a trailing blade, each blade being defined by successively adjoined edge portions comprising, a leading edge extending outwardly from said support, a substantially semi-- circular outer edge, and a trailing edge returning to said support, the trailing edge of said leading blade and the leading edge of said trail ing blade joining said support farther from said member than the leading edge of said leading blade and the trailing edge of said trailing blade and on each blade the distance between the junction of said leading edge with said support and the junction of said trailing edge with said support being substantially less than the diameter of said semi-circular outer edge.

3. In a fluid propulsion device of the character described, a series of pairs of blades having at least their leading edges or their trailing edges in a common plane and, their working surfaces canted from said plane to their other edges, the blades of each pair constituting a primary blade and a secondary blade, whose center lines intersect in radially spaced relation to the axis of rotation and whose widths increase outwardly from said intersection, the leading edges of blades of each pair being on chordal lines which intersect adjacent said centerline intersection, a line along the leading edge of a secondary blade of a pair and a line along the trailing edge of the primary blade of said pair intersecting and a line along the trailing edge of a secondary blade of said pair and a line along the leading edge of the primary blade of a successive pair also intersecting, and the angle of divergence subtended between said first intersecting lines being greater than the angle of divergence subtended between said second intersecting lines and the point of intersection of said second intersecting lines being spaced from the axis of rotation a distance greater than the distance from the rotational axis to the point of intersection of said first intersecting lines, the several successive blades being thus asymmetrically spaced with the pairs in symmetrical balance, whereby the angularly directed fluid streams from primary and secondary blades impinge and merge as a substantially columnal jet.

4. A fluid transfer device comprising, an axle, a support extending transversely of said axle, a pair of blades connected to said support on each side of said axle with the leading edges of the blades of each pair intersecting at equally spaced distances from said axle and diametrically opposite each other with relation to the working surfaces of said axle, saidblades extending at equal angles to a plane transverse to said axle and being pitched so that the trailing edges are outwardly of the leading edges in the direction of fluid flow, the leading edge of the leading blade .of each pair being skewed at an angle with a radial line contacting said leading edge at substantially its mergence with the outer edge of said leading blade and in a direction opposite the direction of rotation and the trailing edge of the trailing blade of each pair being skewed at an angle with a radial line contacting said leading edge at substantially its mergence with the outer edge of said trailing blade and in the direction of rotation.

5. A fluid propulsion device having a pair of diametrically opposite primary blades and a pair of diametrically opposite secondary blades, each primary blade having a leading edge extending generally at an acute angle backwardly from its point of intersection at its outer terminal with a radial line and each secondary blade having its leading edge extending generally at an acute angle forwardly from its point of intersection at its outer terminal with a radial line, the center lines of the blades of each pair intersecting in radially spaced relation from the axis of rotation and the leading edges of the blades of each pair being on chordal lines which intersect adjacent said center line intersection.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,933,948 Weber Nov. '7, 1933 2,386,154 Weber Oct. 2, 1945 FOREIGN PATENTS Number Country Date 1,670 Great Britain of 1879 2,906 Great Britain of 1876 215,211 Great Britain May 8, 1924

Images