Low profile scrubber

A floor scrubbing machine for tile and other hard surface floors has a low enough profile height that it can be operated bodily under furniture or equipment such as, for example, seats in fast food stores. This floor scrubber has three principle functioning components, comprising a tank for cleaning solution and means to apply that solution to the floor, a powered scrub brush to agitate the solution on the floor, and a vacuum pickup squeegee system which dries the floor after scrubbing by removing spent solution from the floor to an on board tank. Floor scrubbers are known which comprise the three above elements, but are too tall to operate under the seats of fast food stores, except with a remote wand attachment which is cumbersome and slow. Other floor scrubbers are known which are low enough to operate bodily in such places but lack a vacuum pickup squeegee system for drying the floor, and leave a hard surface floor unacceptably wet, or require following operations to dry it. The present invention overcomes the shortcomings of these prior art floor scrubbers.

BACKGROUND 
The rise of fast food chains has been a phenomenon of our times. All over 
the country one finds these stores that sell hamburgers, french fries, 
chicken, soft drinks and such for taking out or eating on the premises. As 
with any food service business, zealous attention to cleanliness is 
essential in these establishments, and ease of cleaning is given careful 
thought in the design of the stores. This architectural foresight often 
shows in the floors, which are usually surfaced with ceramic tile, and in 
the seats and tables provided in the dining areas, which are commonly 
built with cantilevered supports so that most of the floor area under them 
is unobstructed. These features, of course, are intended to make it easier 
to clean the floor, which gets all kinds of food dropped on it, as well as 
mud, snow etc. tracked in from outdoors. 
However, these under seat areas do not have a very high floor clearance. A 
survey of a group of fast food stores found that almost two-thirds of them 
had seats with a largely unobstructed area under them which had a vertical 
clearance from the floor to the undersides of the seats that was between 
eleven and fifteen inches. It is not easy to clean the floor under these 
seats because scrubbing machines built low enough to get under them and do 
a good fast job of cleaning and drying the floor are not available. 
Various types of floor cleaning machines are used, but none of them is 
completely satisfactory. 
So-called automatic scrubbers are available which are comprised of a tank 
for cleaning solution and means to apply that solution to the floor, one 
or more powered rotating scrub brushes to agitate it on the floor and a 
vacuum pickup squeegee system to dry the floor after scrubbing by removing 
the solution from the floor to an on board tank. These do good fast 
cleaning, and their vacuum pickup squeegees leave a hard surfaced floor 
barely damp. It will be dry enough to walk on safely and will be 
completely dry in a few minutes. However, they are intended for cleaning 
aisles and open areas, and they are too tall to get under equipment and 
furniture that have only eleven to fifteen inches of floor clearance. This 
is because these scrubbers have relatively large tanks, they require a 
substantial plenum space above the water level in their recovery tanks to 
assist in controlling foam, and commonly their vacuum fans are placed 
above their recovery tanks. The best that can be done when scrubbing the 
floor of a fast food store with these machines is to park them in the 
aisle and use a wand attachment with a long vacuum hose to clean under the 
seats. The wand is cumbersome and slow to use. Typical examples of this 
type of floor scrubber are the Drynamic.about. 170 floor cleaning system 
made by Tennant Trend of Niagara Falls, N.Y., and the Convertamatic.about. 
high-speed floor maintenance machines made by Advance Floor Machine 
Company of Spring Park, Minn. 
Other floor cleaning machines are available which have small bodies with a 
low enough profile height to be pushed bodily under equipment and 
furniture having a floor clearance of even less than eleven inches. They 
all have one or two powered rotating scrub brushes and do a good job of 
cleaning the floor. However, there isn't enough room in one of their small 
bodies for a system to dry the floor after scrubbing, which necessitates 
following after them with a wet vac or a mop and a wringer bucket. This 
substantially increases the time needed to clean and dry a floor. An 
example is the Windsor Grouthog.about. made by Windsor Industries Inc. of 
Englewood, Colo. 
The need for water pickup is recognized in some of these low profile 
scrubbers, but there isn't room enough in their bodies for a vacuum pickup 
squeegee system so they are built with other means to pick up used scrub 
water. Thus the Rotowash machines distributed by R. E. Whittaker Co. of 
New Castle, Pa., have two rotating cylindrical scrub brushes which fling 
water onto a slowly rotating drum between them. This water is carried up 
and over the top of the drum where a scraper wipes it off and directs it 
into a recovery tank. Experience has shown, however, that such water 
pickup systems do not dry a floor anywhere nearly as well as a vacuum 
pickup squeegee system does. Nothing has been found that will dry a hard 
surface floor as well as a vacuum pickup squeegee system, and to our 
knowledge the prior art has not produced a low profile scrubber with one. 
Many fast food stores resort to a mop and a wringer bucket, and the results 
of using them leave much to be desired. Mopping is slow work, tends to 
slop dirty water on adjoining walls, and will leave a wet or still dirty 
floor if carelessly done. 
Fast food stores are not alone in facing this problem. Other types of 
business establishments have furniture and equipment with a vertical 
clearance from the floor up to the lowest part of the equipment that is 
similar to the clearance under seats and tables in fast food stores. 
Examples might be counters and ovens in institutional kitchens such as in 
hospitals, nursing homes and schools, also work benches, storage racks, or 
machine tools in industrial plants. The present invention could be useful 
in such places, but for simplicity we will limit our discussion to fast 
food stores. 
It is apparent that there is a long felt need which has been unfilled at 
least as long as there has been a fast food industry for a hard floor 
cleaning machine having the elements of an automatic scrubber (i.e. 
solution storage and distribution, powered scrubbing brush, and vacuum 
pickup squeegee with storage of dirty water) but capable of being pushed 
bodily under seats and tables (or other equipment having similar clearance 
above a floor) and scrubbing there as well as present automatic scrubbers 
do in aisles or other unobstructed areas. 
SUMMARY OF THE INVENTION 
The primary object of the invention is to provide a floor scrubber for tile 
and other hard surfaced floors, the body of which has a low enough profile 
height that it can be pushed under the seats and tables found in most fast 
food stores, or under other equipment having a similar clearance above the 
floor, which may be taken as eleven to fifteen inches, said floor scrubber 
comprising a tank for cleaning solution and means to apply that solution 
to the floor being scrubbed, a powered scrub brush to agitate the solution 
on the floor, and a vacuum pickup squeegee system to dry the floor by 
removing spent solution from the floor to an on board tank. 
Another object is to use only one tank or bucket in the scrubber to hold 
clean scrubbing solution and also to receive and hold dirty solution 
picked up by the vacuum squeegee, thereby eliminating a separate tank for 
receiving soiled solution from the squeegees and thus contributing to the 
low profile height of the scrubber body by reducing the tank volume in 
said body, as well as providing extended run time by recycling at least 
some of the scrubbing solution. 
Another object is to provide a tank in the form of a bucket within the 
scrubber body for holding a prescribed amount of scrubbing solution, and 
to make this bucket relatively shallow in relation to its length and width 
to reduce its height. 
Another object is to provide said tank in the form of a removable bucket 
for holding cleaning solution within the body of the scrubber, so that 
said bucket can be lifted out of the body when it is desired to empty it, 
thereby eliminating any need for providing a drain with attendant vertical 
dimensions in the bottom of the solution tank or bucket. 
Another object is to provide a minimum height plenum above the removable 
bucket, said minimum height contributing to the low profile height of the 
scrubber body. 
Another object is to provide a novel system for minimizing the generation 
of foam in said plenum, said novel system being functional in spite of the 
minimum height of the plenum. 
Another object is to provide a duct fluidly connecting said plenum with an 
exhaust blower for partially evacuating air from above the bucket. 
Another object is to locate said exhaust blower essentially on a level with 
and alongside of the bucket rather than above the bucket to reduce the 
height of the scrubber body. 
Another object is to dispose the scrubber elements within the scrubber body 
in a generally horizontal relationship to each other rather than a 
vertical arrangement. 
Another object is to provide a handle attached to the body of the scrubber 
by the use of which a walking operator can push or pull, steer and control 
the scrubber, said handle being pivotally attached to said body so that on 
occasion said handle may be lowered to not interfere with pushing said 
body under seats and tables or other equipment. 
Another object is to provide a hand control associated with said handle by 
the use of which the operator from a position behind the machine or to 
either side of it can start or stop the scrub brush and the flow of 
cleaning solution, so that these scrubbing functions can be easily 
controlled at all times, regardless of where the operator may stand while 
pushing the scrubber body under seats and tables or other equipment. 
Another object is to provide a floor scrubber having a pickup squeegee in 
front of the powered scrub brush and another one behind the brush so that 
the scrubber can scrub and pick up cleaning solution while moving forward 
or backward. 
Another object is to locate a scrub head comprising the scrub brush and a 
brush cover comprising the two pickup squeegees and a solution 
distributing means at the front of the scrubber body so that an operator 
of the machine can push it up to a wall and the machine will scrub and dry 
the floor right up to the wall.

DETAILED DESCRIPTION OF THE DRAWINGS 
Referring now to FIG. 1A, there is shown a low profile floor scrubbing 
machine 10 in use scrubbing the floor of a fast food store. In particular, 
the work is being done under two seats 12 such as are typically found in 
the dining booths of such establishments. A study has found that in the 
majority of such seats there is vertical clearance from the floor to the 
undersides of the seats ranging from eleven to fifteen inches, and 
scrubber 10 has a low enough profile height to operate in this head room. 
The floor 14 will have a hard surface, typically grouted ceramic tile or 
quarry tile, and the scrubber 10 is particularly adapted to operate on 
this type of floor by virtue of its cylindrical brush and vacuum pickup 
squeegee system. FIG. 1B shows another view of scrubber 10 operating under 
seats 12. This time the scrubber has been pushed under the seats in a 
direction relative to the seats which is 90 degrees from the direction it 
is being pushed in FIG. 1A. 
FIG. 2 shows a right side view of the scrubber 10. A molded plastic housing 
16 is the main structural part; other drawings show details of its 
construction. A scrub head indicated generally at 30 is mounted on the 
front of the machine, and a vacuum suction hose 32 runs from scrub head 30 
to housing 16. A molded plastic cover 34 on the top of the housing 16 
gives access to internal components and cooperates with other parts in 
controlling water and air flow, as will be discussed later. The weight of 
the scrubber is carried on two rear caster wheels 18 and one front wheel 
20. 
Referring to FIG. 4, it will be seen how front wheel 20 can be set at a 
height to support the scrub brush 66 at its best working height, and how 
this may be adjusted as the brush wears. It will also be seen how a 
transport height is provided where the brush and squeegees 72 are clear of 
the floor. 
Toe pedal 39 is pivotally attached to housing 16 at pivot point 41. Hand 
screw 43 is threaded into pedal 39 and bears against housing 16 to 
adjustably position pedal 39. Rod 45 is pivotally attached to pedal 39 and 
runs forward through a tunnel in housing 16 to a pivotal attachment with 
bell crank 47, which supports front wheel 20. The working height of brush 
66 is maintained by wheel 20, and can be adjusted by turning hand screw 43 
in or out. 
Toe pedal 39 can be pushed down to a position shown as 39A, which it holds 
until pushed up because rod 45 is then in an over center position. This 
action causes rod 45 to push forward on bell crank 47, which lowers wheel 
20 to a transport position shown in dotted outline where the brush 66 and 
the squeegees 72 will be lifted clear of the floor. 
As seen in FIG. 2, a molded plastic handle 22 is pivotally attached to the 
housing 16, and can pivot from a vertical position for storage to a 
horizontal position, which may be used when the scrubber is to be pushed 
far under a piece of overhanging furniture or equipment. 
The machine draws its power from a wall outlet through power cord 24. A 
control module 26 on handle 22 provides switches to control the scrubber 
functions, and the switched signals travel to the scrubber body via power 
cable 28. A thumb switch 27 which controls the vacuum blower 42 is shown 
on the control module 26, and other switches as needed may also be there. 
Referring to FIG. 3, there is shown a hand control 29. In its position 
shown in solid lines it is spring loaded (spring not shown) so that bar 33 
bears against normally closed snap action switch 31, thus holding this 
switch open. Switch 31 controls current to motor 68 which drives scrub 
brush 66 and in normal scrubbing also controls current to motor 54 which 
drives solution pump 52. Thus when hand control 29 is positioned as shown 
in solid lines the scrub brush will not rotate and in normal scrubbing 
pump 52 will not run, so no cleaning solution will be delivered to the 
floor. 
It is easy for a machine operator to reach hand control 29 with his or her 
fingers and hold it in the position shown in dotted outline 29A. This will 
move bar 33 away from snap action switch 31, which assumes its normally 
closed position. Then scrub brush 66 will rotate and in normal scrubbing 
pump 52 will deliver cleaning solution to the floor. 
Hand control 29 has two shoulders 35 formed on it. These make it possible 
to operate switch 31 by pulling control 29 sidewise as well as straight. 
Thus if an operator pulls control 29 sideways as indicated by arrow 37, 
the control will pivot around the shoulder 35 nearest arrow 37. This will 
move the central part of bar 33 away from switch 31, thus effectively 
closing the switch. This makes it possible for the operator to control the 
scrub brush and solution flow whether he or she is standing behind the 
machine or to one side of it. This can be handy when maneuvering the 
scrubber into some restricted spaces. 
Housing 16 has a double wall, which can be seen in FIGS. 4 and 5, and 
provides the surrounding walls and part of the bottom for the scrubber 
body. It also provides a large upward opening cavity 36 which may be seen 
in FIGS. 4 and 5, and a downwardly opening cavity 40 that may be seen in 
FIG. 5. Upward opening cavity 36 primarily houses a removable tank or 
bucket 38 to hold cleaning solution, while downward opening cavity 40 
houses a vacuum blower 42 and its motor 44 and other parts which will be 
discussed later. A sheet steel plate 46 covers the bottom of cavity 40. 
Cover 34 covers the upward opening cavity 36. A gasket 48 seals it to the 
housing. Bucket 38 has a normal water level 50 and has a folding handle 
(not shown) by means of which it can be lifted out of the scrubber for 
emptying when cover 34 is removed. This avoids providing it with a bottom 
drain, which would add t its vertical dimensions and thus to the height of 
the scrubber. It will be noted that bucket 38 is also rather shallow 
relative to its width and length, further reducing its height. 
A pump 52 and its drive motor 54 are shown in dotted outline in FIG. 3. In 
the bottom of bucket 38 there is a screened intake 56 connected to tube 58 
by means of which pump 52 draws cleaning solution from the bucket. A quick 
release coupling 60 in line 58 is easily disconnected when it is desired 
to remove the bucket. Pump 52 delivers cleaning solution through flexible 
tubing 62 to a perforated stainless steel tube or manifold 64 in the scrub 
head 30, from which the solution is sprayed on the floor. 
Scrub brush 66 is carried by two bearings 67 (only one shown) mounted in 
two forward arms 69 which are part of housing 16. It is rotated by a motor 
68 and a drive belt 70. It agitates the cleaning solution on the floor, 
scrubbing and cleaning it thoroughly. 
In front of and behind brush 66 are pickup squeegees 72, best seen in FIG. 
4. Air passages 74 in scrub head 30 connect the squeegees to a common 
outlet 76 so that vacuum is applied to both squeegees. They have an 
automatic valving action such that when the scrubber is pushed forward the 
front squeegee valves itself shut and the entire vacuum is applied to the 
rear squeegee for maximum water pickup and floor drying behind the brush. 
When the scrubber is pulled backward the rear squeegee closes and the 
front one opens, so that the squeegee that is behind the brush in the 
instantaneous direction of travel will always be open and the one 
instantaneously ahead of the brush will always be closed. Thus a strong 
vacuum squeegee wiping and drying action on the hard surface floor 14 
takes place whether the scrubber is being pushed or pulled. This squeegee 
construction and action is fully discussed in U.S. Pat. No. 4,817,233, 
U.S. Pat. No. Re. No. 33,926, so will not be further described here. 
It should be further noted, however, that by placing the scrub brush and 
squeegees at the extreme front of the scrubber it is possible to scrub 
right up to a baseboard, which is a useful characteristic when the job to 
be done is to scrub the floor under restaurant seats or the like. 
Air outlet 76 is round, and threaded on its outside. A nut 78 can be run by 
hand up and down these threads. A compression spring 80 surrounds outlet 
76 and bears against an extended lip 82 of housing 16, so the spring 80 
can be more or less compressed by turning nut 78. This will adjust the 
down pressure on the squeegees for optimum wiping and drying. Flexible 
hose 32 is connected at one end to outlet 76 and at the other end is push 
fitted into a hole in the forward wall of housing 16. A rigid plastic ring 
84 is a tight fit on hose 32. When the front end of the scrubber is lifted 
for transport, spring 80 pushes the squeegee assembly down until ring 84 
strikes the top side of housing extension 82. Then the squeegees can go no 
lower, and will be lifted off of the floor for transport. A soft doughnut 
shaped rubber seal 86 is cemented to the housing 16 around the hole where 
suction hose 32 is inserted. Bucket 38 presses against seal 86 so that 
water entrained with the air coming through suction hose 32 will be 
directed into the bucket, and will not run down outside of it. 
The stream of air and entrained water coming into bucket 38 from suction 
hose 32 impinges on the upper sloping surface of diffuser 88. Here the 
water spreads out in a sheet across the surface of the diffuser while the 
air expands into the space above the water level 50 and below the cover 
34. In the process both water and air lose velocity. The water runs down 
the slope of the diffuser and drops into the bucket. Vacuum blower 42 
pulls the air through air passages 90 into air duct 92. This leads to a 
structure 94 at the inlet to vacuum blower 42. A gasket 96 seals the duct 
to the inlet structure. The mouth of the inlet structure is protected with 
a screen 98, which in turn is protected with a cap 100. The lower wall of 
air duct 92 is molded integrally with diffuser 88, and the entire part is 
attached to cover 34 with screws around the air duct, two of which are 
shown as 102 in FIG. 5. Suction blower 42 draws in air through inlet 
structure 94 and exhausts it out around the periphery of its casing into 
downward opening cavity 40. From there the air passes to atmosphere 
through several holes 104 in bottom cover plate 46. 
A light weight float 106 can slide up and down on the shank of wing bolt 
108. If for some reason the water level 50 in bucket 38 should get 
abnormally high the float would rise and block off air flow through air 
passages 90, thus stopping the air flow and protecting suction blower 42, 
and also stopping the flow of air and water into the bucket 38. 
There are several baffle plates 110 and 112 which depend from diffuser 88. 
Also there is a deflector 114 which depends from cover 34 and follows 
around inside the entire perimeter of bucket 38. These baffles and 
deflectors are to control sloshing of water in the bucket, which otherwise 
would become quite pronounced and would generate foam as the scrubber is 
alternately pushed and pulled back and forth during operation. 
When water that contains detergent is entrained in air and moved at high 
speed as happens in vacuum pickup squeegee systems, the airflow is 
turbulent and tends to generate foam. On occasion foam can accumulate in 
the top of the recovery tank in a scrubber until it fills the duct to the 
suction blower. Then it goes through the blower and is thrown out to 
atmosphere, making a glorious mess and possibly damaging the blower. 
Scrubbers using vacuum pickup squeegees all cope with this problem. Ducts 
with gradually expanding cross sectional area are sometimes used to slow 
the flow velocity; so are scroll wrap impingement plates. Universally a 
substantial plenum space is provided above the water level in the recovery 
tank to accumulate foam and give it time to settle. The sloping diffuser 
plate 88 used in the present invention is innovative, and is thought to be 
unique. It serves to slow the turbulent airflow and spread the cleaning 
solution over the diffuser surface so it forms a laminar flow, thus 
minimizing foam. This is done with a much lower plenum volume above the 
water level than used in other scrubbers, which is a major factor in the 
low profile of the machine. 
It will be noted that the same bucket is used to store clean solution 
before pumping it to the floor and to receive soiled solution picked up 
from the floor after scrubbing. The solution in the bucket thus becomes 
progressively dirtier. However, up to a point dirty water works as well as 
clean water for scrubbing. When it becomes too dirty then the bucket must 
be emptied and refilled, but before then the solution in the bucket will 
have been recycled several times, making in effect a single tank recycling 
system. For a given run time, then, a smaller tank can be used than if 
there were no recycling, and this smaller tank in turn contributes to 
reducing the profile height of the machine. 
In summary, the present invention provides a low profile scrubber for hard 
surface floors, said scrubber having a tank for cleaning solution and 
means for applying that solution to the floor, a powered brush to agitate 
solution on the floor, and a vacuum pickup squeegee system to remove 
soiled solution from the floor to an on board tank, leaving the hard 
surface floor dry enough that it can dry completely in a few minutes. 
Novelty lies in the fact that a scrubber of this type has a low enough 
profile height that it can operate bodily under overhead structures such 
as, for example, the majority of seats found in fast food stores. 
In the preferred embodiment as described, the above useful end has been 
accomplished by a new combination of a number of known elements and one or 
more new elements. A single tank is used for recycling cleaning solution, 
and that tank is relatively shallow with respect to its length and width. 
This tank is removable for emptying, so it has no bottom drain. The 
necessary suction blower is set alongside the tank, not on top of it, with 
modified ductwork to conduct air from the tank to the blower. Other 
elements inside the scrubber, e.g. the brush motor and the solution pump, 
are disposed horizontally, not vertically. The handle is pivotally 
attached in a manner that permits lowering it to horizontal when necessary 
to push the machine far under an overhanging structure. And significantly, 
a novel diffuser system, aided by several anti-slosh baffles, is employed 
to control foam in a plenum having considerably less height than is 
commonly provided in scrubbers. 
The above elements were combined in the preferred embodiment to achieve the 
objects of the invention. However, there are always many possible 
solutions to any problem in machine design, and it is possible that the 
objects of the invention could be achieved by a different combination of 
the same or other elements. It is therefore desired that the invention be 
unrestricted except by the appended claims.