Gear type grease pump

A gear type grease pump includes a motor fixed on the top surface of a base plate, a gear type pump fixed on the bottom surface of the base plate, the pump having a pair of gears engaged with each other and rotationally driven by the motor for rotating, a housing body and a bottom cover for accommodating the two gears, and a grease inlet and a grease outlet opposite to the grease inlet both provided on the housing body. A grease sweeping blade is located below the bottom cover and driven by the pump. A sealing ring is fixed along the bottom surface periphery of the base plate. A perforated mesh hood is located within the sealing ring and encloses the gear type pump and the grease sweeping blade. And a grease path is provided inside the base plate to communicate with the grease outlet path when the pump is fixed on the base plate, and the outlet of the grease path is connected with a conventional grease gun. Since the entire grease pump is loaded with grease, the grease having the tendency to flow into the grease inlet is fed into the pump, and the pump steadily squeezes out the grease.

FIELD OF THE INVENTION 
The present invention relates to a grease pump, and more particularly to an 
improved structure of a gear type grease pump, such that the grease can 
steadily enter into the pump and be squeezed out. 
BACKGROUND OF THE INVENTION 
In conventional grease pumps, grease within a grease barrel is sucked up to 
a pump actuated by pressurized air, it then flows out via the outlet of 
the grease gun and is squeezed through a grease nipple into the bearing 
housing of machine parts. It is very difficult to suck up the grease by 
such conventional grease pumps of pressurized air type due to the high 
viscosity of the grease. It has been found in practical operation that the 
grease around the pump can not be easily pushed into the empty region by 
utilizing the pressure difference between the vacuum degree in the pump 
and the atmospheric pressure acting upon the grease surface in the grease 
barrel. Therefore, after using the conventional grease pump of pressurized 
air type for several times, practically the pump has to be shaken by the 
user to vibrate the grease into the empty region so as to perform the next 
sucking/injection steadily. 
SUMMARY OF THE INVENTION 
The object of the present invention is therefore to provide an improved 
structure of a gear type grease pump which can fill up the empty region 
around the grease inlet of the pump with grease, and make the grease 
around the grease inlet of the pump always have the tendency to flow so as 
to perform the operation of sucking/injection of the grease steadily. 
The grease pump according to the present invention comprises a gear type 
pump actuated by a motor, and a perforated rigid mesh hood surrounding the 
gear type pump. Thus, when the grease pump of the present invention is 
placed inside a grease barrel being full of grease with the rigid mesh 
hood downward the empty region of the grease pump in the mesh hood is 
surrounded and filled with grease due to the fact that the entire weight 
of the grease pump presses the grease within the grease barrel and forces 
the grease to flow through many meshes on the mesh hood. Therefore, by 
means of the present invention, it is assured that the grease always has a 
tendency to flow into the grease inlet of the pump and the grease pump is 
kept in steady operation. 
Another object of the present invention is to provide a grease sweeping 
blade located under the grease inlet of the pump and actuated by the 
motor, whereby to further force the grease entered into the mesh hood to 
flow to the grease inlet to be sucked up and squeezed out so that the 
grease flow rate can be stabilized.

DETAILED DESCRIPTION OF THE INVENTION 
Referring to the gear type grease pump of the present invention shown in 
FIGS. 1 and 2, which comprises a motor 1 being in an upright status and 
fixed on the top surface of a base plate 2, with the rotary axis 101 
penetrating downward into the base plate 2 and fitted into the bearing 3 
which is mounted on the bottom surface of the base plate 2. A gear type 
pump 4 is mounted on the other surface of the base plate 2 and driven by 
the rotary axis 101 of the motor 1. As shown in FIG. 3, the gear type pump 
4 comprises a housing body 401 for accommodating a driving gear 402 and a 
driven gear 403, engaging with each other; a bottom cover 404 for covering 
the bottom opening of the housing body; a grease collecting cap 405 in 
inverted "U" shape, being fixed above the grease inlet 4011 provided on 
the housing body; and a grease sweeping blade 406 positioned below the 
bottom cover 404 and driven by the axis 4021 of the driving gear 402 
protruding out of the bottom cover 404. Moreover, the grease outlet 4012 
on another side wall of the housing body 401 and opposite to the grease 
inlet 4011 communicates with the grease outlet path 407 provided within 
the side wall of the housing body 401. The grease outlet path 407 
communicates with the grease path 201 provided within the base plate 2 
when the pump is fixed to the base plate 2. The opening of the grease path 
201 on the top of the base plate 2 communicates with a pressure release 
valve 6 and a conventional grease gun 12 respectively via a three-way cock 
5. 
Finally, the pump 4 is enclosed with a perforated rigid mesh hood 7, and a 
flexible sealing ring 8 of horn type is fixed along the bottom surface 
periphery of the base plate 2. 
The grease pump formed according to the present invention is placed inside 
of a grease barrel 9 (filled up with grease) with the mesh hood 7 downward 
as shown in FIG. 1, and the flexible sealing ring 8 is pushed outward 
against the inner wall of the grease barrel 9. The grease barrel 9 is put 
into an outer barrel 10 which is covered by an outer cover 11. Having 
placed the grease pump as described above, the motor 1 is turned on to 
actuate the driving gear 402 of the pump, so the driven gear 403 and the 
grease sweeping blade 406 are also driven to rotate synchronously. Since 
the grease pump of the present invention is placed on top of the grease 
surface and the entire weight of the grease pump presses on the grease 
surface through the mesh hood 7, the grease flows into the mesh hood 7 
through the meshes of the mesh hood 7, causing parts of the grease pump 
below the base plate 2 to immerse in the grease, the parts are totally 
covered with the grease which has a tendency to flow. The rotation of the 
grease sweeping blade 406 further enhances the tendency of the grease to 
flow into the grease inlet. Therefore, the grease continuously flows into 
the pump through the grease inlet and is squeezed out by a pair of gears 
with high pressure, and through the grease path and the conventional 
grease gun to inject into the bearing of a machine. 
During the operation of the grease pump, the grease within the mesh hood 7 
is gradually consumed. However, in the course of consumption, since the 
weight of the grease pump is always pressing on the grease via the mesh 
hood 7, the grease inside the grease barrel 9 and outside the mesh hood 7 
is forced to pass through the meshes of the mesh hood 7 continuously, to 
flow into the mesh hood 7 and fill it up, and maintain the tendency of the 
grease to flow into the grease inlet. After the grease of grease barrel 9 
is totally consumed, the user will then pull out the grease pump from the 
empty grease barrel, and place the grease pump upon another new grease 
barrel so as to proceed the next grease pumping operation. 
To sum up all the foregoing, the tendency of the grease flowing into the 
pump grease inlet is maintained by using the gear type grease pump of the 
present invention, so as to assure stability of the grease input as well 
as to maintain normal operation of the grease pumping. Therefore, the 
present invention is really novel