Vacuum cleaner assembly with low vacuum inlet

A vacuum cleaner of the wet or dry tank type having a vacuum inlet introduced at the base of the tank and an internal conduit conducting the flow of matter from the vacuum inlet to the top of the tank and discharging matter from the top of the tank downward into the accumulation area of the tank, the entry of the vacuum inlet through the wall of the tank sealed to preserve liquid tight and air tight integrity of the wall of the tank, a flexible external vacuum hose connecting to the vacuum inlet at the base of the tank.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The invention relates to tank type vacuum cleaners and more particularly to 
the type of vacuum cleaner that is especially adapted to use in the home, 
in the workshop, and in industry as a wet or dry type vacuum and the 
primary object of the present invention is to provide an improved device 
of this character. 
2. Description of Prior Art 
The wet or dry shop vacuums presently in the marketplace characteristically 
consist of on open top collection tank mounted on wheels or casters and a 
cover or lid in which an electric motor and fan unit are mounted. The fan 
unit creates a suction within the tank and debris and liquid are drawn 
into the tank through a vacuum hose which is connected to an inlet located 
in the cover of the tank or to an inlet located high on the side of the 
tank itself. The air being drawn from the inside of the tank and through 
the fan is filtered to prevent dust and debris from reaching the motor and 
fan unit and to prevent dust and debris-laden exhaust from being expelled 
into the environment in which the vacuum is being operated. While filter 
methods vary, the most usual is a cylindrical filter of paper, cloth, or 
other porous material suspended from the cover of the tank and 
incorporating a check ball or float arrangement which cuts off suction to 
the fan unit should the liquid level in the tank rise to a level at which 
it threatens to enter the motor and fan unit itself. Caster mounts and 
casters located around the lower circumference of the tank give the vacuum 
cleaner mobility and the operator normally drags the vacuum assembly over 
the surface being vacuumed using the external vacuum hose as a tow line. 
The advantages of the above described arrangements are apparent to anyone 
practiced in the art: (1) the fan and electric motor unit is relatively 
isolated from debris and especially from liquids coming into and being 
stored in the tank, (2) the arrangement readily lends itself to a filter 
and filter housing located below the motor and fan unit, attached to the 
cover, and containing a simple ball or float check valve, (3) the location 
of the inlet which connects to the vacuum hose in the cover of the 
assembly or at a point high up along the side of the tank makes it 
possible for a large amount of debris and liquid to accumulate in the tank 
before such accumulation reaches a level which would close off the vacuum 
inlet and (4) the location of the heavy operating machinery of the vacuum 
in and attached to the cover of the assembly makes for convenience and 
ease of emptying the tank inasmuch as the weight of the operating 
machinery is removed when the cover is removed. 
The disadvantages of the above described arrangements are readily apparent 
to anyone who has ever actually used the wet or dry shop vacuums which are 
currently in the marketplace and fit the above description: (1) the 
location of the electric motor and fan unit at the top of the assembly 
creates a high center of gravity which results in extreme vertical 
instability for the entire assembly and (2) the location of the vacuum 
hose inlet in the cover at the top of the assembly or in the side of the 
tank a short distance down from the top of the tank causes the operator to 
exert substantial leverage on the inherently unstable assembly when the 
operator attempts to drag the vacuum forward using the vacuum hose as the 
tow line. When the casters or wheels on which the assembly is mounted 
encounter any debris or obstruction, or even such resistance as is offered 
by a thick pile carpet, and the operator attempts to pull the unit forward 
using the vacuum hose as a tow line, the combination of high center of 
gravity and substantial mechanical advantage produced by the high 
connection point for the vacuum hose conspire to cause the vacuum cleaner 
assembly to capsize. 
The problem of extreme vertical instability created by the high center of 
gravity found in wet or dry vacuums now in the marketplace is solved in a 
novel and simple manner by the invention disclosed in my co-pending 
Application entitled "Wet or Dry Vacuum with Low Center of Gravity". The 
problem of substantial leverage produced by an external hose connection 
located high on a wet or dry vacuum assembly and the destabilizing effect 
of attempting to tow the assembly using the external vacuum hose as a tow 
line is dealt with and solved in a simple and novel manner by the present 
invention. 
The degree of increased stability achieved by lowering the connection point 
for the external vacuum hose will vary from one vacuum assembly to 
another, depending upon the weight distribution and center of gravity of 
the assembly itself. The substantial decrease in mechanical advantage that 
comes with lowering the vacuum connection to the base of the assembly is 
apparent. The relationships between the parts are the relationships of the 
parts of a second class lever: the point on the floor at which resistance 
or an obstacle stops the forward motion of a caster being the fulcrum, the 
weight of the assembly concentrated at its center of gravity being the 
resisting force, and the forward pressure being applied to the external 
vacuum hose being the applied force. When the external vacuum hose is 
moved from a connection point at the top of the assembly, for example two 
feet above the fulcrum, to a point at the base of the assembly three or 
four inches from the fulcrum, the loss of mechanical advantage is such 
that approximately six times as much applied force is required to lift and 
capsize the assembly. 
SUMMARY OF THE INVENTION--OBJECTS AND ADVANTAGES 
The principal object of the present invention is to provide an improved 
vacuum cleaner assembly with the vacuum inlet located at the base of the 
tank. 
Another object of the present invention is to provide an internal conduit 
which conducts debris and liquids from the vacuum inlet at the base of the 
tank to the top of the tank and discharges such debris and liquids in a 
generally downward direction into the accumulation area of the tank, 
eliminating the problem of accumulated debris or liquid blocking discharge 
of new debris or liquid entering the tank. 
Another object of the invention is to introduce the vacuum inlet through 
the wall of the tank in a manner that ensures both air tight and liquid 
tight integrity of the tank and to connect the internal vacuum hose to the 
vacuum inlet in a manner that ensures both air tight and liquid tight 
integrity of the connection. 
Another object of the disclosed invention is to achieve the above objects 
in a manner that is unique, simple, and lends itself to ease of assembly 
and low production cost. 
The principal advantage of the disclosed invention is that it makes 
practical the connection of the external vacuum hose at the base of the 
tank and in substantially the same horizontal plane as the caster mounts 
attached to the lower circumference of the tank thereby enhancing the 
vertical stability of the vacuum cleaner assembly of which the tank is a 
part, making it possible for the operator of the assembly to tow the 
assembly by the external hose without leverage sufficient to capsize the 
assembly when the casters or wheels encounter resistance on the surface 
being vacuumed. 
Further objects and advantages of the invention will become apparent from a 
consideration of the drawings and the ensuing description.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring now to the accompanying drawings wherein like reference numerals 
denote the same parts throughout the various views, there is disclosed in 
FIG. 1 a vacuum cleaner tank generally designated as 10, being generally 
cylindrical in shape and having a vertical wall 11, a rolled upper edge 
12, a plurality of releasable fasteners for connecting a removable cover 
(not shown) to tank 10, a base 14, and a plurality of caster mounts 15 and 
casters 16 attached around the lower circumference of tank 10. Tank 10 is 
comprised of plastic and is manufactured by molding. 
An annular vacuum inlet 17 which is adapted to connect with a conventional 
external flexible vacuum hose (not shown) is introduced through an annular 
opening 18 in vertical wall 11. Annular vacuum inlet 17 has female threads 
cut for a predetermined distance around its exterior surface and is molded 
to and an integral part of internal vacuum hose 19 as seen in FIG. 3. 
Vertical wall 11 of tank 10 is molded to an increased thickness forming 
plateau 20 projecting out from the external surface of vertical wall 11 a 
predetermined distance and surrounding annular opening 18 by a 
predetermined distance. The exterior face of plateau 20 follows the 
cylindrical curve of vertical wall 11 with the molded exterior face of 
plateau 20 flattened for a predetermined distance around annular opening 
18 and the molded cylindrical curve of the interior face of vertical wall 
11 is flattened for a predetermined distance surrounding annular opening 
18, providing parallel flat surfaces against which external resilient 
gasket 21 and internal resilient gasket 22 mate when compressed by plastic 
nut 23 and plastic nut 24 forming water tight and air tight passage for 
vacuum inlet 17 through vertical wall 11. The thickness of vertical wall 
11 is increased at the top by plateau 25 which is a molded integral part 
of vertical wall 11. Internal vacuum hose 19 rises in a fair curve from 
vacuum inlet 17 to plateau 25 where it is held by clamp 26 with the 
discharge opening of internal vacuum hose 19 facing in a generally 
downward direction. Clamp 26 is connected to plateau 25 by screw fasteners 
27. 
FIG. 5 discloses a vacuum cleaner assembly generally designated as 28 
having a tank 10, a plurality of caster mounts 15, a plurality of casters 
16, a rolled upper edge 12, a plurality of releasable fasteners 13 
connecting a cover 28 to tank 10. Cover 28 houses electric motor (not 
shown) and fan unit (not shown) and exhaust air outlet (not shown). Vacuum 
inlet 17 at base of tank 10 connects to flexible external vacuum hose 29. 
Some variations and modifications of the structure herein disclosed will 
suggest themselves to those skilled in the art. Rigid molded annular 
tubing can be used rather than a flexible internal vacuum hose, so long as 
curves in the tubing remain fair. Flexible internal vacuum hose is used in 
the preferred embodiment because the nature of the material is such that 
it is disposed to select fair curves for itself and flexible hose is easy 
to install and easy to remove and to clear should debris clog the interior 
vacuum line. In the preferred embodiment the vacuum inlet passes through 
an annular opening in the vertical wall of the tank and liquid tight and 
air tight integrity around the vacuum inlet is achieved by sealing means. 
The vacuum inlet can be molded as a part of the tank wall with the molding 
itself being the sealing means. The vacuum inlet, if molded as a part of 
the tank, can be lowered so as to enter the tank partly in the base of the 
vertical wall and partly in the base of the tank, but with a minimal 
increased advantage in stabilizing the assembly when the assembly is 
towed. The internal conduit itself can be molded into and made a part of 
the tank itself but the vacuum inlet and internal conduit of the preferred 
embodiment recommends itself as requiring least sophisticated molding 
technique and maximum simplicity in manufacture and assembly. 
Wet or dry shop vacuums now in the marketplace conduct debris and liquid 
waste up an external vacuum hose to a vacuum inlet in the cover of the 
assembly or high up on the side of the tank and then discharge debris and 
liquid waste down into the tank. In the disclosed invention, debris and 
liquid waste makes the same vertical ascent, but it does so through an 
internal vacuum hose within the tank thus making it possible to connect 
the external vacuum hose to a vacuum inlet located at the base of the tank 
The low connection point provides little leverage for pulling the assembly 
over when the operator pulls on the external vacuum hose and the casters 
encounter resistance on the surface being vacuumed. 
The disclosed invention substantially enhances the vertical stability of 
wet or dry shop vacuums, including the shop vacuums having a high center 
of gravity. The disclosed invention provides maximum advantage when used 
in combination with the invention disclosed in my co-pending application 
"Wet or Dry Vacuum with Low Center of Gravity". 
While other variations and modifications may suggest themselves, it is to 
be understood that the present disclosure relates to a preferred 
embodiment of the invention which is for purposes of illustration only and 
is not to be construed as a limitation of the invention. All such 
modifications which do not depart from the spirit of the invention are 
intended to be within the scope of the appended claims.