Note: Descriptions are shown in the official language in which they were submitted.
20 0029 6
KNOCKED-DOWN FAN FOR ENGINE COOLING
ANU OTIIER APPLICATIONS
BACKGROUND OF TIIE INVENTION
This invention relates generally to fans, and
particularly to those of the class used for engine cooling
and like applications, Still more particularly, the
invention pertains to a fan of novel knock-down construction
designed for the ease of assemblage and high performance
characteristics,
By the term "fan" as used herein and in the claims
attached hereto is meant any propeller-type device for
imparting motion and acceleration to air or other gases and
operating on the centrifugal principle, Thus the invention
should be construed to comprehend devices that may be
commonly classified as blowers,
Internal-combustion engines such as those used on
motor vehicles are normally equipped with a fan as a part of
the engine-cooling system, Normally mounted on the water-
pump shaft driven from the engine via a fan belt, the engine
fan functions to provide a powerful draft of air through the
radiator, A typical construction of the engine fan has been
such that a set of fan blades have been riveted respectively
to arms or spokes. radiating from a hub, The hub and spokes
1
20 002 9 6
may be a unitary apiece of sheet metal,
This type of engine fan, as so far constructed, has
had some shortcomings, Such shortcomings arise from the fact
that the fan blades should not overlap, as seen in a front
view, to such an extent as to interfere with the riveting of
the successive blades to the spokes, Limitations have
therefore been imposed on the shape, size and number of fan
blades that could be employed, The number of fan blades has
had to be reduced if they are each increased in size for
higher rates of air delivery, Conversely, if the number of
fan blades is increased, the size of each blade has had to be
reduced,
Such limitations on the prior art have made it
difficult to make the rate of air delivery as high as can be
desired, and the air pressure has been easy to pulsate, It
might be contemplated to drive the fan at higher speeds for
higher rates of air delivery, This solution would not be
realistic because, driven at high speeds, the engine fan
would generate inconveniently large amounts of vibrations and
noise, particularly if it had a relatively small number of
blades,
SUMMARY OF TIIE INVENTION
The present invention provides a fan of novel
2
2,p pp296
knocked-down construction whereby any desired practical
number or size of fan blades can be employed without the
possibility of interfering with the assemblage of fan,
Briefly, the invention may be summarized as a
knocked-down fan for engine cooling and other applications,
comprising at least two fan assemblies of like construction,
Each fan assembly comprises hub means having an axis of
rotation, and a plurality of fan blades riveted or otherwise
attached radially to the hub means with equal angular
spacings between the fan blades, The fan assemblies are
combined by having their hub means joined together, typically
by riveting, in axial alignment and with the fan assemblies
angularly displaced from each other by half the pitch of the
fan blades of each fan assembly,
The fan blades are to be riveted to the hub means
of the two separate fan assemblies before they are joined
together, In each such fan assembly the angular distances
between the fan blades are twice as much as those between the
fan blades of the completed fan, Each blade~can therefore be
riveted to the hub means of each fan assembly without being
hampered by the' neighboring blades, Thus the fan can be
readily assembled with use of practically any desired number
or size of blades to provide a desired rate of air delivery
at constant pressure,
Typically, the hub means of each fan assembly takes
3
20 00296
the form of a sheet-metal hub integral with radiating spokes each having one
blade riveted
thereto. The spokes of at least either of the two fan assemblies may be offset
into coplanar
relation with those of the other fan assembly so that the blades of the two
combined fan
assemblies may rotate in one and the same plane. The performance of the
resulting fan will
then be totally free from amy adverse effect that might be feared to arise
from the joining of
the two fan assemblies in axial alignment.
Aspects of the present invention are as follows:
A knocked-down fa:n for engine cooling and other applications, comprising:
at least two fan assemblies of like construction, each fan assembly comprising
hub
means having an axis of rotation, each of said hub means comprising a hub and
a plurality of
spokes each having one fan blade attached thereto and extending radially from
the hub, the
fan blades having equal angular spacings therebetween;
wherein the hub me~~ns of the fan assemblies are joined together in axial
alignment,
with the fan assemblies angularly displaced from each other by half the pitch
of the fan
blades of each fan assembly; and
wherein the spokes of the hub means of one of the fan assemblies are offset
into
coplanar relation with the spokes of the hub means of the other fan assembly
whereby the fan
blades of the fan assemblie:e rotate in the same plane.
A knocked-down fa~1 formed by combining two fan assemblies of like
construction,
each fan assembly comprising:
a) a spider comprising a hub and a plurality of spokes extending radially from
the
hub; and
b) a plurality of fan blades mounted one to each spoke of the spider;
wherein the hubs of the spiders of both fan assemblies are firmly joined
together in
axial alignment;
wherein the spider of each fan assembly is fabricated from sheet metal, and
wherein the spokes of the spider of one of the fan assemblies are offset
toward the
other fan assembly a distance equal to the thickness of the sheet metal
whereby the spokes of
both fan assemblies are in the same plane at right angles with the axis of the
fan.
A knocked-down fa~z for engine cooling and other applications, comprising:
a) at least two fan assemblies of like construction, each fan assembly
comprising hub
means having an axis of rotation, and a plurality of fan blades attached
radially to the hub
4
2000296
means with equal angular spacings between the fan blades;
b) the hub means of the fan assemblies being joined together in axial
alignment, with
the fan assemblies angularlv displaced from each other by half the pitch of
the fan blades of
each fan assembly;
c) the hub means of each fan assembly comprising a hub and a plurality of
spokes
extending radially from the hub, each spoke having one fan blade attached
thereto, the spokes
of the hub means of both th~~ fan assemblies being offset into coplanar
relation with one
another whereby the fan blades of the fan assemblies rotate in one and the
same plane.
A knocked-down faal formed by combining two fan assemblies of like
construction,
each fan assembly comprising:
a) a spider comprising a hub and a plurality of spokes extending radially from
the
hub; and
b) a plurality of fan. blades mounted one to each spoke of the spider;
c) the hubs of the spiders of both assemblies being firmly joined together in
axial
alignment;
d) the spider of each fan assembly being fabricated from sheet metal, and the
spokes
of the spider of each fan assembly being offset toward the other fan assembly
a distance equal
to half the thickness of the :sheet metal whereby the spokes of both fan
assemblies are in the
same plane at right angles vrith the axis of the fan.
The above and other features and advantages of this invention and the manner
of
realizing them will become more apparent, and the invention itself will best
be understood,
from a study of the following description and appended claims, with reference
had to the
attached drawings showing some preferred embodiments of the invention.
BRIEF DE SCRIPTION OF THE DRAWINGS
FIG. 1 is a front elevation of a knocked-down engine fan embodying the
principles of
this invention, the fan comprising two fan assemblies disposed behind the
other in axial
alignment;
FIG. 2 is a front elevation of the front fan assembly of the engine fan;
FIG. 3 is a front elevation of the rear fan assembly
4a
2000296
of the engine fan;
FIG.4 is a side elevation of the sheet-metal hub
members or spiders of the engine fan, shown together with
only one of the fan blades attached thereto for illustrative
convenience;
FIG.5 is a front elevation of the spider of the
rear fan assembly of FIG.3;
FIG,6 is an enlarged fragmentary section through
the spider of FIG S. taken along the line VI-VI therein; and
F1G.7 is a front elevation of the spider of the
front fan assembly of FIG.2.
DESCRIPTION OF TILE PREFERRED EMBODIMENTS
The knocked-down fan of this invention will now be
described more specifically as adapted for use as an engine
cooling-system fan, Generally designated 10 in FIG.1, the
knocked-down engine fan exemplifying the invention is shown
as a combination of two fan assemblies 12 and 12' of like
construction disposed one behind the other, The front fan
assembly 12 is shown by itself in FfG.2, and the rear fan
assembly 12' in FIG.3. It will be seen that FIGS.2 and 3
show the fan assemblies 12 and 12' in the same angular
positions about their axes as they are depicted in FIG.1.
As will be understood from FIG.2, the front fan
2000296
assembly 12 comprises a' hub member 14 known to the
specialists as a spider because of the resemblance of its
appearance, and a plurality of, four in this embodiment, fan
blades 16 fastened to the spider 14. This spider takes the
form of a sheet--metal punching integrally comprising a hub
18 and a set of .four arms or spokes 20 extending radially
from the hub with a constant angular pitch spacing of 90
degrees, The flan blades 16 are riveted at ZZ to the
respective hub spokes 20 via sheet-metal retainers Z4, with
each fan blade engaged between one hub spoke 20 and one
retainer 24.
It will be appreciated that the four fan blades 16
of the front fan assembly 1Z employed in this embodiment are
angularly spacedl from one another much more widely than the
eight fan blades of the complete fan 10 of F1G.1. Therefore,
if the fan blades 16 are riveted to the hub spokes ZO before
the two fan arse:mblies 12 and 12' are joined together, the
riveting of each fan blade will not be hampered by the
neighboring fan blades of the same fan assembly, (t will
also be understood that the width, or dimension in the
circumferential direction of the fan, of each fan blade 16
can be far greater than if the fan 10 were not divided into
the two separate assemblies 12 and 1Z', as has been the case
heretofore,
The hub 18 has a mounting hole 26 of relatively
6
20 0029 6
large diameter formed centrally therethrough for use in
mounting the fan 10 on, for example, the water-pump shaft of
an internal-combustion engine, An annular row of six
additional mounting holes 2$ of smaller diameter are formed
concentrically around the central mounting hole 26 for use in
fastening the fan 10 to, for example, a fan pulley on the
water-pump shaft, Another annular row of eight holes 30 in
the hub 1$, also centered about the hub axis, are rivet holes
for use in fastening together the two fan assemblies 12 and
12' .
Despite the showing of FIG.2, it is not essential
that the holes 26, 2$ and 30 be formed in the hub 18 before
the front fan assembly 12 is combined with the rear fan
assembly 12' as in FIG, 1. The rivet holes 30, in
particular, should preferably be formed after the two fan
assemblies 12 and 12' are held together in the correct axial
and angular positions as in FIG.1. in order to firmly unite
the fan assemblies in the required relative positions.
The construction of the front fan assembly 12 as
so far described with reference to FIG.2 applies to that of
the rear fan assembly 12' illustrated in FIG.3. Therefore,
in this and other drawings, the various parts of the rear fan
assembly 12' are indicated by priming the reference numerals
used to denote the corresponding parts of the front fan
assembly 12. No repeated explanation of such parts of the
7
20 0029 6
rear fan assembly 12' is considered necessary,
As will be understood by referring back to FIG.1,
taken together with FlG.4. the two fan assembly 12 and 12'
are fastened together by rivets 32 passing through the rivet
holes 30 and 30' in the hubs 18 and 1$', The fan assemblies
are united in alignment about the hub axis 1(-X but with an
angular difference equal to half the pitch of the fan blades
16 and, 16' of each fan assembly, Since each fan assembly 12
or 12' has four blades with a pitch angle of 90 degrees in
this particular embodiment, the two fan assemblies 12 and 12'
are joined with an angular displacement of 45 degrees from
each other about l:he hub axis x-x, providing a total of eight
fan blades 16 and 16. with an equal pitch spacing of 45
degrees,
Incidenl:ally, FIG.4 shows only the spiders 14 and
14' of the fan assemblies 12 and 12' in their correct
relative positions;, together with only fan blade 16' in order
to reveal the twist imparted to each hub spoke 20 or 20',
Such twist of the; hub spokes 20 and 20', and the resulting
angles of the fan blades 16 and 16' with respect to the
principal plane of the fan 10, is of course needed for the
air-moving function of the fan,
Although the two fan assemblies 12 and 12' are
essentially alike in construction, a slight difference exists
in this embodiment in order to make the fan blades 16 and 16'
8
2000296
of both fan assemblies rotate in one and the same plane.
Toward this end the hub spokes 20' of the rear fan assembly
12' are offset into coplanar relation with the hub spokes 20
of the front fan assembly 12, as discussed in more detail in
the following,
As will be noted from FIGS.5 and 6, the hub spokes
20' of the rear fan assembly 12' are each twisted at its
region Y, in the: immediate vicinity of the hub 18', to hold
the associated fan blade 16' at the required angle set forth
with reference to FIG,4. At this twisted part Y each hub
spoke 20' is offset forwardly a distance equal to the thic-
kness T of the sheet metal of which the spiders 14 and 14'
are made, into coplanar relation with the hub spokes 20 of
the front fan assembly 12, With the hub spokes 20 and 20' of
the two fan assemblies 12 and 12' thus disposed in coplanar
relation to each other, the fan blades 16 and 16' rotate in
the same plane just like those of the conventional undivided
fan, It will, of course, be understood that the hub spokes
20 of the front :fan assembly 12 could be offset into coplanar
relation with the hub spokes 20' of the rear fan assembly
12' .
As has been mentioned, the mounting holes 26. 26'.
28 and 28' and rivet holes 30 and 30' may not necessarily be
formed in the hubs 18 and 1$' before the fan assemblies 12
and 12' are united as shown in FIG,1. Unly the central
9
2000296
mounting holes 26 and 26' may be preformed in the hubs 18 and
18' to facilitate the boring and other operations to be
performed subsequently on the hubs,
However, in some instances, it may be desirable to
preform all such holes in the hubs 18 and 1$', as in the
quantity production of the fan assemblies 12 and 12' inclu-
ding those to be held in sock for future use as replacements,
In such cases the holf;s may be arranged as shown in FIG S in
the hub 18' of the rear fan assembly 12' and as shown in
FIG.7 in the hub 18 of the front fan assembly 12. Since each
hub has four spokes in this embodiment, the eight rivet holes
30 and 30' can be of the same arrangement in each hub 18.
18'. The arrangement of the six mounting holes 28. 28' must
differ between the hubs 18 and 18'. The angle Z, FIG.7.
between one of the mounting holes 28 in the hub 18 and the
centerline of thc: adjacent spoke 20 is 15 degrees whereas the
angle Z', FIG,5, between one of the mounting holes 28' in the
hub 18' and the centerline of the adjacent spoke 20' is 30
degrees,
Althoul;h the present invention has been shown and
described in very specific aspects thereof and as embodied in
engine cooling-system fans, it is not desired that the
invention be limited by the exact details of the illustrated
embodiments, For example, three or more, instead of two, fan
assemblies could be combined into a single fan, The number
2000296
of fan blades of each fan assembly could also be greater or
smaller than four, Still further, the two or more fan
assemblies could be united by means other than riveting, such
as screwing, bolting, welding, adhesion, etc, The knocked-
down fan of this invention may not include any means for
joining the fan a:csemblies if they are welded together, All
such and additional modifications, alterations or adaptations
of the invention may be resorted to without departing from
the proper scope or fair meaning of the following claims,
11
