Direct drive fan with X-shaped motor mounting

A direct drive cooling fan employs a specially configured, X-shaped mounting chassis to securely mount the drive motor. The preferred fan comprises a parallelepiped housing protectively enclosing an internal subframe securing a drive motor and a propeller. A reinforcing edge circumscribes the housing front and rear to facilitate guard coupling. The subframe comprises two parallel elongated brackets, each formed of channel material. Each strut comprises several regularly spaced apart follower slots to which the X-shaped mounting chassis is mounted. The preferred mounting chassis comprises a pair of complimentary brackets welded to opposite sides the drive motor shell. The brackets comprise a curved, interior cradle that flushly mates with the circumferential periphery of the drive motor. The brackets have wings at either end of the cradle terminating in tabs laying parallel with the subframe brackets. An attachment hole on each tab allows for the attachment of the mounting chassis to the subframe brackets. This attachment creates increased internal strength and allows for the torsional forces generated by the drive fan to be dissipated evenly throughout the fan housing. The diametrically aligned cradle wings form an X-shaped profile with the motor at the center.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates generally to agricultural and industrial 
ventilation fans. More particularly, my invention relates to low-vibration 
ventilation fans of the type comprising fan blades that are directly 
connected to the drive motor. 
2. Description of the Prior Art 
It has long been recognized in the fan arts that moving air may be 
conveniently used to ventilate an area while simultaneously cooling it. A 
variety of fans are used extensively in agricultural facilities, 
especially in the poultry and dairy industries, to provide both 
ventilation and cooling. 
To practically control the effects of wind or air cooling, it is desirable 
to control the direction, velocity, and volume of the air being driven. I 
have previously proposed a fan adept at controlling air over long ranges. 
My previous invention, issued as U.S. Pat. No. 5,480,282, on Jan. 2, 1996, 
and its teachings are hereby incorporated by reference. It was classified 
in U.S. Class 415, subclass 125. As can be seen from that patent and the 
prior art therein, the known prior art comprises many different types and 
designs of fans adapted to satisfy various criteria. 
In the prior art it has been required to mount fans relatively close to the 
area to be cooled because the velocity of the expelled air drops 
dramatically as it leaves the fan. When expelled air leaves typical fans, 
extreme turbulence generated by the fan causes the expelled air to mix 
with surrounding air. The intermixing of the expelled air with the ambient 
air surrounding the fan results in a drop in volume, speed and pressure of 
the expelled air. This phenomena requires that the fan be mounted 
relatively close to the application it is to cool. It is often difficult 
to mount the fan as close as required to the application, in part because 
industrial-quality drive motors are very heavy, and the influence of 
vibration and extreme loads on the drive-train tends to degrade or loosen 
structural mounting parts over time. 
To maximize the distance in which the fan will operate, the air must be 
concentrated and delivered properly for maximum effect. Concurrently, the 
fan must be properly mounted upon a suitable structure. It is also 
desirable to prevent workers from inadvertently contacting the fan, to 
avoid both mechanical and electrical injury. It is generally prohibited to 
mount fans with extension cords and other exposed electrical wiring. 
Most industrial designs use a rectangular housing enclosing a multi-bladed 
fan that is belt driven at relatively high velocity. Such "tube axle" 
designs have several advantages. They are durable and rugged. They are 
relatively uncomplicated and easy to build. However, such fans can be 
noisy and they tend to vibrate, with vibration intensity often increasing 
over time. Loud, continuous rattles are annoying and distracting. Further, 
vibration can eventually loosen critical parts causing misalignment or 
premature breakdown. The long term structural durability of such fans is 
of paramount importance. 
One cause of fan vibration relates to the "V-belts" or drive belts. In such 
fans the blade tip speed must be less than approximately one hundred miles 
per hour to minimize noise. Typically the fan speed is reduced from the 
motor speed by a ratio of three to one. This gear reduction results from 
the pulleys of various sizes connected by the V-belt. Over time typical 
V-belts will eventually wear and deform. Thereafter the tension 
transmitted by the belt between the axis of rotation of the fan blades and 
the drive motor axis will vary in response to rotation. An annoying 
oscillating effect can result. Unwanted vibration causes fan shaking and 
noise. Direct drive motors may ameliorate the problem of worn or distorted 
drive belts, and they reduce vibration and noise. But the motors in direct 
drive fans can be difficult to mount. 
Another vexatious problem with conventional industrial fans involves 
structural deformation. Over time, internal stresses and dynamic forces 
generated during normal operation can misshape the fan, distorting the 
housing from the optimum round cross section. Many industrial fans are 
roughly moved about as necessary for spot cooling. Often these fans are 
mishandled, dropped, or subjected to other damaging forces through 
carelessness and the like. Known prior art fans are not designed to 
maximize structural strength. They fail to adequately compensate for 
stresses exerted by the motors and other internal components upon the 
housing during movement. Their guards fail to make a maximum contribution 
to structural integrity. 
Finally, a problem with conventional fan housings involves the numbers of 
components that must be handled during assembly and maintenance. 
Conventional guards and guard attachment devices require handling and 
installing several parts during manufacture as well as removing a 
corresponding number during routine maintenance. Also, most conventional 
mounting brackets use several components pieces that require considerable 
assembly time. Such brackets are often difficult to handle and store. 
The trend toward direct drive fans and their inherent simplicity has been 
the driving force to improve motors and their application to ventilating 
fans. In a direct drive ventilation fan the fan blades are rotated through 
direct contact with the drive motor. These direct drive motors turn at a 
slower speed than motors in conventional belt drive systems. For example, 
to obtain the correct blade speed for a 36 inch fan the direct drive motor 
need only turn 850 RPM. The conventional belt-driven fan, comprising a 
conventional capacitor start motor turning approximately 1750 RPM, 
requires two pulleys to divide the fan speed range down to approximately 
500-800 RPM. Direct drive systems eliminate the complex speed reduction 
system. This greatly reduces the vibration and noise associated with 
conventional belt and pulley systems. 
Conventional systems for mounting motors and engines has evolved around the 
need to support the center of the torque moment. In many industries large 
engines have mounting arrangements that isolate vibration and control 
torque with circular placement of isolation points. In some cases, several 
isolation mounts are located in a circular pattern to maintain shaft 
alignment and absorb torsional shock. 
Small electric motors are available with concentric elastomeric mounting on 
each end of the motor to maintain concentricity and isolate vibration. 
Many mounting bases are offered as add-on isolation and belt-tensioners 
but do not maintain concentricity. Base mounted isolators by their very 
shape are unstable and allow harmonic movement, rendering them undesirable 
for close tolerance fan applications. Motor mounting for perfect 
concentricity and rigidity is well accomplished with the "C" face 
mounting. The "C" face motor requires an adapter plate to complete a 
mounting system for a fan. Any plate used for mounting also acts as an air 
deflector and causes turbulence that reduces the cooling effect of the air 
flow. 
When motors are used to directly drive a fan blade it is desirable to have 
an unobstructed flow of air over the motor. Some fans have add-on flat 
mounting strips and lugs that allow attachment of flat plates which extend 
to the fan housing. These strips are mounted parallel with the air flow 
and obstruct the flow very little. Flat strips, however, and similar 
mounting methods tend to vibrate more than most arrangements. This type of 
mounting system must be limited to small motors. 
Thus it is desirable to provide a fan with a highly efficient direct drive 
motor and a cooperating mounting system that provides a rigid support near 
the center line of the mass of the motor. Also it is desirable that the 
free flow of air over the motor housing be unobstructed. 
SUMMARY OF THE INVENTION 
My improved X-shaped motor mounting system greatly improves the operation 
of direct drive fans. My design overcomes several of the above referenced 
problems with known prior direct drive fans. 
The fan preferably comprises a generally parallelepiped housing 
protectively enclosing several internal fan components. The fan components 
include an internal venturi fitting adjacent a vertically oriented 
mounting subframe. The subframe secures the fan shell inside the housing. 
A pair of detachable safety guards cover the front and rear housing faces. 
The housing comprises a hollow, box-like frame separating an air intake end 
and a high output end. The frame has an open front and rear face bounding 
a parallel top and bottom and parallel side walls. A reinforcing edge 
circumscribes the frame adjacent each end. The edge comprises an angled 
brace adjacent to a top peripheral lip. The lip is perforated by several 
regularly spaced apart, elongated slits. Corresponding fastener orifices 
penetrate the frame walls adjacent to the slits. 
Each guard comprises a wire mesh that prevents inadvertent contact with the 
internal fan components. Normally the guards may be removed to service the 
fan as necessary. The frame preferably encloses an internal venturi 
attached to the interior of the frame walls by screws or welds or other 
conventional securing devices. The subframe permanently attaches to the 
venturi and to the walls of the housing in a similar fashion. 
The subframe comprises a pair of spaced apart, generally parallel elongated 
struts. The struts are preferably orientated vertically. Each strut is 
penetrated by several equidistantly spaced, elongated follower slots. The 
subframe secures the fan within the enclosure. 
A unique, cross-shaped mounting chassis mounts the drive motor to the 
subframe. The motor is coaxially disposed adjacent spaced apart intake and 
outlet venturis. The motor directly drives and rotatably controls a 
conventional propeller to vigorously establish an airflow. The chassis 
comprises a pair of cooperating, wing-shaped brackets that terminate in 
suitable tabs for engaging the subframe struts. One bracket is welded to 
each side of the drive motor shell. The chassis is selectively positioned 
between the struts with appropriate fasteners that secure the tabs to 
suitable follower slots. The direct drive electrical motor is thus 
symmetrically mounted by the chassis between the struts, with the wing 
portions of the chassis brackets diametrically aligned to form an X-shaped 
appearance. 
The parallel, vertical struts span the housing interior and rigidly support 
the motor without compromising the air flow. The mounting points at the 
distal ends along the radius of the cross-shaped mounting chassis connect 
to the support struts. The chassis legs and the subframe support struts 
form a brace for the support of the drive motor and the attached fan 
propeller blades. This brace transfers forces and stresses generated by 
the internal components during fan operation to the wheels and stand of 
the fan, which in turn dissipate the transferred forces and stresses to 
the support surface (i.e., the ground). 
Thus a primary object of this invention is to provide a direct drive 
ventilation fan that maximizes airflow. 
Yet another fundamental object of this invention is to provide a rigid 
mounting system for a direct drive ventilation fan. 
Another important object is to provide a fan of the character described 
characterized by the efficiency of direct drive without the cost of 
reduction drive systems. 
Another important object is to provide a direct drive ventilation fan for 
cooling applications that may be mounted in a variety of orientations. 
Another object is to provide a direct drive fan of the character described 
that totally isolates all rotating blades within a safe, protected shroud 
to avoid direct human contact. 
Another object is to provide a direct drive fan that provides a high volume 
of non-turbulent cooling air. 
Another object is to provide a highly reliable fan system which moves the 
maximum amount of air possible through the minimum volume of fan. 
Another important object is to provide a unique venturi effect that enables 
the fan to project air long distances. 
A still further object is to provide a direct drive ventilation fan which 
is readily capable of use either inside or outdoors. 
Yet another object of my fan is provide a direct drive ventilation fan that 
can be suspended from a ceiling or upon a wall. 
Another object is to provide a direct drive ventilation fan which can cool 
a plurality of industrial workers, to minimize the number of fans which a 
company may need for proper cooling or ventilation. 
A further object is to provide a direct drive ventilation fan which creates 
and expels a column of moving air as far as possible. 
A major object is thus to provide a heavy duty direct drive ventilation fan 
that will not deform during operation. 
Another fundamental object is to provide a direct drive ventilation fan 
that is highly stable. 
Another object of this invention is to produce a direct drive fan of the 
character described that can be quickly assembled and whose parts, once 
assembled, synergistically reinforce the entire apparatus to prevent the 
fan from becoming "out-of-round." 
Yet another object of the invention is to produce a direct drive 
ventilation fan of the character described whose construction details lead 
to higher manufacturing precision. It is a feature of the invention that 
the structure disclosed insures a consistent cylindrical shape and 
maintains a circular cross section. 
Another important object is to provide a low vibration direct drive fan. 
A related object of the present invention is to provide mounting chassis 
for the fan motor that dissipates internal forces and stresses to 
exteriorly braced housing components. 
A related object of the present invention is to provide a mounting chassis 
for a direct drive fan motor that reduces air turbulence. 
Yet another object is a fan that reduces noise and vibrations, thus 
lowering service costs. 
Another important object is the exchange of a slow turning motor for a 
speed reducer thus eliminating the need for belt and gear maintenance. 
A general object of this invention is to provide a fan of the character 
described which is easy to service in the field and which saves production 
time. 
A still further object is to provide a fan which is readily capable of use 
either inside or outdoors. 
Another object is to provide a fan of the character described that totally 
isolates all rotating blades within a safe, protected shroud to avoid 
direct human contact. 
These and other objects and advantages of the invention, along with 
features of novelty appurtenant thereto, will appear and become apparent 
in the course of the following descriptive sections.

DETAILED DESCRIPTION OF THE DRAWINGS 
With initial reference directed to FIGS. 1-10, my improved fan assembly is 
generally designated by the reference numeral 20. An alternative 
embodiment (FIGS. 3, 4) is designated by the reference numeral 20A. As 
previously stated, improved fans 20, 20A overcome several problems 
inherent with prior art direct drive fans. 
With initial reference to FIGS. 1 and 2, fan 20 comprises a generally 
elongated, preferably tubular housing 25 defining an internal fluid flow 
channel for the passage of cooling air therethrough. Preferably, housing 
25 comprises a generally cubicle frame 30. Frame 30 separates an air 
intake end 32 from a high velocity air output end 34. The frame 30 
protectively encloses several internal fan components 75 including the 
motor, fan blades, etc. In the preferred embodiment, frame 30 comprises a 
rigid, parallelepiped, box-like assembly. Frame 30 has a spaced apart 
parallel top and bottom wall 36A and 36B and spaced apart parallel side 
walls 36C and 36D. Walls 36A-D cooperatively define a hollow, fluid flow 
channel therebetween. 
A removable safety guard 50 substantially obscures each end 32,34. Guard 50 
comprises a substantially rectangular wire mesh 52 that prevents 
inadvertent contact with the internal fan components 75. Wire mesh 52 
comprises a series of inner, horizontal filamentary members 54 crossed by 
another series of vertical filamentary members 56. Thus, criss-crossed 
members 54 and 56 cooperatively form mesh 52. Members 54 and 56 are 
bounded by an integral peripheral outer member 55. Guard 50 is coupled to 
frame 30 by a plurality of selectively displaceable gripping clips 60. 
The preferred fan 20 (FIGS. 1, 2) comprises a venturi fitting 70, mounting 
subframe 80, drive motor 108 and propeller 104. The venturi fitting 70 
primarily comprises a funnel 72. Funnel 72 has a rectangular outer flanged 
periphery 74 and an interior, conic spout 76. The spout 76 compresses the 
input air into a high velocity output stream. The outer funnel periphery 
74 is permanently attached to the walls 36A-D of the frame by screws or 
other conventional attachment devices. 
The subframe 80 (FIGS. 7, 9) comprises a pair of spaced apart struts 82A, 
82B that cooperatively support the cross-shaped mounting chassis 90. 
Struts 82A, 82B preferably extend between the frame top 36A and the bottom 
36B adjacent venturi fitting 70. The preferably channel steel struts 82A, 
82B each comprise an elongated, central planar portion 84A aimed towards 
the motor. An upturned edge 81A formed at the air intake side of the strut 
is parallel with a companion edge 81B at the opposite strut side. Edge 81B 
is integral with an inturned reinforcing lip 81C that is parallel with and 
spaced apart from portion 84A. A plurality of regularly spaced apart, oval 
follower slots 85 are formed in planar portion 84A to facilitate mounting 
and alignment. Offset mounting tabs 86 at the top and bottom of each strut 
are coplanar with edges 81B. Appropriate mounting orifices 87 are formed 
in each tab 86 for flush mounting to appropriate tabs within the fan 
housing. 
The preferred X-shaped mounting chassis 90 (FIGS. 7, 9) comprises two 
similar brackets 92A and 92B placed on opposite sides of drive motor 
shell. The curved central cradle 200 of the bracket 90 conforms to the 
cylindrical periphery of the drive motor 108 (i.e., its shell). Each end 
of the cradle has an outwardly diverging wing 210 which terminates in an 
offset mounting tab 220. Preferably each tab 220 is generally parallel to 
the struts 82A, 84B. Mounting orifices 116 in tabs 220 register with strut 
orifices 85 to enable secure attachment of the chassis to the subframe 80. 
Fasteners comprising suitable mounting bolts 112 and hex nuts 114 are 
employed. Strut follower slots 85 and the cross-shaped mounting chassis 
attachment holes 116 are appropriately sized so that they may overlap. 
Such an overlap permits the chassis 90 to be infinitesimally adjusted 
along struts 82A, 82B to facilitate the use of a wide variety of propeller 
sizes as well as motor sizes. 
In the alternative embodiment 20A (FIGS. 8, 10), frame 30A comprises a 
rigid, parallelepiped, box-like assembly. Frame 30A has spaced apart 
parallel top and bottom wall 37A and 37B and spaced apart parallel side 
walls 37C and 37d. Walls 37 A-D cooperatively enclose and support a 
hollow, fluid flow channel 83 therebetween. 
A removable safety guard 50A substantially obscures each end 32A, 34A. 
Guard 50A comprises a substantially circular wire mesh 52A that prevents 
inadvertent contact with the internal fan components 75A. Wire mesh 52A 
comprises a series of outer, circular filamentary members 103 crossed by 
another series of radial filamentary members 101 and 107. Thus, 
criss-crossed members 103, 101 and 107 cooperatively form mesh 52A. Guard 
50A is coupled to frame 30A by a plurality of removable bolts mounted 
through the distal ends of radial filamentary members 101. 
The internal fan components principally comprise a venturi fitting 83, 
mounting subframe 80A, drive motor 108 and propeller 104. The venturi 
fitting 83 primarily comprises a transition zone 89 within the housing 30A 
where the diameter of the flared end 79A gradually reduces and smoothly 
merges with the uniform diameter of the venturi 83. Propeller 104 is 
attached to the drive motor 108. The propeller and motor assembly is 
mounted within the transition zone to produce a stable high velocity 
output stream of air. 
The subframe 80A (FIGS. 8, 10) primarily comprises a pair of spaced apart 
struts 83A, 83B that support the cross-shaped mount chassis 90. 
Channel-like struts 83A, 83B extend between the top and the bottom of 
venturi fitting 83. Struts 83A and 83B are similar to struts 82A and 82B 
previously discussed. Central strut portions 100 are bounded by opposite 
edges 102 at each side that include inturned lips 102A that are parallel 
with body portions 100. Regularly spaced apart follower slots 85 
facilitate assembly and mounting. 
A transverse foot 140 is formed at each end of the struts 83A, 83B (FIGS. 
8, 10). Feet 140 occupy a plane that is generally perpendicular to the 
plane occupied by central strut portions 100. Each foot 140 comprises a 
pair of parallel mounting orifices 142 for attachment to the internal 
circumferential boundary of the venturi 83 (FIG. 3). 
From the foregoing, it will be seen that this invention is one well adapted 
to obtain all the ends and objects herein set forth, together with other 
advantages which are inherent to the structure. 
It will be understood that certain features and subcombinations are of 
utility and may be employed without reference to other features and 
subcombinations. This is contemplated by and is within the scope of the 
claims. 
As many possible embodiments may be made of the invention without departing 
from the scope thereof, it is to be understood that all matter herein set 
forth or shown in the accompanying drawings is to be interpreted as 
illustrative and not in a limiting sense.