Gear box of air fan

A gear box for storing gears of a swinging controller of an air fan in the gear box includes an upper cover fixed on the gear box and integrally formed by plastic molding process to form two screw holes in situ in the upper cover for saving a manual drilling and tapping operation so that an outer housing may be secured on the gear box by a screw inserted into one of the two screw holes formed in the upper cover for encasing the gear box and a fan motor inside the housing.

BACKGROUND OF THE INVENTION 
A conventional air fan such as a desk fan placed on a desk for blowing air 
for cooling purpose includes a swinging controller adjacent to a motor of 
the fan having a gear box provided in a rear portion of an air fan having 
a control lever which can be pulled upwardly for posing the fan at a fixed 
air blowing direction, or depressed downwardly for swinging the air fan 
either rightwardly or leftwardly for cooling purpose. Such a gear box 
provided for the swinging controller of the air fan is always made of 
metallic material. For securing a motor housing on the gear box for 
encasing the gear box and the motor within the motor housing, the metallic 
gear box should be first drilled with two round holes which are then 
tapped for forming female threads in the two round holes so that two 
screws may be fixed into the two threaded holes for securing the motor 
housing on the gear box to be fixed on a fan frame. 
Drilling and tapping the two screw holes in the metallic gear box will 
require labor, and thereby increase production cost and reduce the 
competitive potential of a fan-making industry. 
The present inventor has found the drawbacks of a conventional air fan and 
invented the present air fan provided with integrally formed gear box 
cover secured on the gear box. 
SUMMARY OF THE INVENTION 
The object of the present invention is to provide a gear box for storing 
gears of a swinging controller of an air fan in the gear box including an 
upper cover fixed on the gear box and integrally formed by plastic molding 
process to form two screw holes in situ in the upper cover for saving a 
manual drilling and tapping operation so that an outer housing may be 
secured on the gear box by a screw inserted into one of the two screw 
holes formed in the upper cover for encasing the gear box and a fan motor 
inside the housing.

DETAILED DESCRIPTION 
As shown in FIGS. 1, 2 and 3, a gear box of the present invention 
comprises: a gear-box casing 1 secured with an upper cover 2 for securing 
a motor housing 3 thereon for encasing the gear box and a fan motor inside 
the housing 3. The gear-box casing 1 may be made of metallic materials 
such as an aluminum alloy through casting process. The upper cover 2 is 
integrally formed by plastic molding process. 
The gear-box casing 1 is formed with a socket 10 recessed in an outer 
surface of the casing 1 having a socket wall 11 circumferentially formed 
in the socket 10 and two longitudinal extensions 12 vertically formed on 
two opposite side portions of the socket wall 11 of the casing 1. 
The casing 1 includes a lower lever sleeve 14 protruding downwardly from 
the casing 1 for pivotally mounting a control lever 141 of a swinging 
controller 141 for operatively swinging an air fan 4 as shown in FIG. 4 in 
one side portion of the gear box and a gear-spindle sleeve 15 protruding 
downwardly from the casing 1 for pivotally mounting a gear spindle 151 in 
the other side portion of the casing 1 having a driving wheel 152 secured 
on a lower portion of the gear spindle 151 engageable with a pinion 142 
formed on a lower portion of the control lever 141. Upon an upward pulling 
of the control lever 141, the pinion 142 is disengaged from the driving 
gear 152 to allow the air fan to blow air at a fixed direction without 
being swung. Upon a downward depression of the lever 141, the gear 152 
will be engaged with the pinion 142 for reciprocatively swinging the air 
fan. The swinging mechanism of a desk air fan is so conventional wellknown 
in the art so that their detailed structures are not described in detail 
herewith. 
The casing 1 further includes: an upper casing surface 13 having a 
plurality of screw holes 18 vertically formed in a side wall portion 19 of 
the casing 1 for inserting screws therein through the other plural screw 
hole 25 formed in the upper cover 2 for securing the upper cover 2 on the 
lower casing 1; a motor-shaft sleeve 16 such as made of copper bush 
laterally formed in the casing for passing a motor shaft therein for 
driving a worm gear set (not shown) provided in the gear box to be 
operated by the control lever 141 which serves as a clutch for operatively 
swinging or fixedly posing the air fan; and a bracket 17 protruding 
sidewardly from the casing 1 to be secured on a motor or fan frame by 
screws (not shown). 
The upper cover 2 sealed on an upper opening of said casing 1 includes: a 
protrusion plate 21 protruding downwardly from an outer portion of the 
cover 2 having two longitudinal grooves 22 respectively recessed in two 
opposite side portions of the protrusion plate 21 slidably engageable with 
the two longitudinal extensions 12 formed in the socket 10 of the casing 
1, at least a round hole 23 integrally formed through the protrusion plate 
21, and an upper lever sleeve 24 for pivotally mounting an upper portion 
of the control lever 141. The round holes 23 are formed in situ in the 
protrusion plate 21 during the molding process so as to save a drilling 
processing work after integrally forming the upper cover 2. 
The socket wall 11 of the casing has a cross section of generally U shaped 
as shown in FIG. 2. The shape of the plate 21 of the cover 2 and the shape 
of the socket 10 of the casing 1 are preferably made as rectangular, but 
are not limited in this invention. 
When installing the present invention, the protrusion plate 21 of the upper 
cover 2 is inserted into the socket 10 of the casing 1 by engaging the 
extensions 12 of the casing 1 with the groovesd 22 of the protrusion plate 
21 of the upper cover 2 and a plurality of screws are further inserted 
into the screw hole 25, 18 formed in the cover 2 and the casing 1, the 
upper cover 2 will be firmly secured on the casing 1. The motor housing 3 
as shown in FIG. 3 will then be secured on the gear box of the present 
invention by fixing a metal screw or bolt 32 through the fixing hole 31 
formed in a rear portion of the housing 3 and through anyone hole of the 
round holes 23 formed in the cover 2 which is already fixed on the 
gear-box casing 1. During the insertion of the screw or bolt 32 as shown 
in FIG. 4, a male-threaded portion on the screw or bolt 32 will form a 
female-threaded porition in situ in the round hole 23 for securing the 
screw or bolt 32 in the hole 23 for firmly securing the housing 3 on the 
cover 2 and casing 1 of the gear box on the dfan frame of the air fan 4. 
The other hole 23 of the cover 2 is provided for securing any other 
element (not shown) of the swinging controller. 
The present invention has the following advantages superior to a gear box 
of a conventional air fan: 
1. There is no need to pre-drill round holes in the metallic gear box and 
then to tap the round hole to form female threads for the insertion of a 
screw for fixing a motor cover on the gear box. The round holes 23 are 
integrally formed in the plate 21 of the upper cover of the present 
invention. Since the upper cover 2 is made of plastic material, a metal 
screw can be rotatably inserted into the round hole 23 for securing the 
motor housing 3 on the gear box. 
2. If the screw holes are formed on the casing 1 of the gear box as found 
in a conventional gear box of air fan, any product of poor quality of the 
gear box such as an improper drilling or tapping of the screw holes may 
cause a rejection of the whole set of gear box. Comparatively, if the 
cover 2 of this invention is formed with poor holes 23, only the cover 2 
is rejected, which is still more economic than a rejection of a larger 
casing of the gear box.