Floor buffing machine with automatic pad pressure adjustment

An electric buffing machine and a method buffing waxed floors are disclosed. The buffing machine comprises a molded plastic housing, a foldable handle and a DC drive motor directly driving a buffing pad holder. The pad is movable into and out of engagement with the floor by a pad lifter mechanism which raises and lowers the pad holder along a splined drive shaft of the drive motor. The pad lifter mechanism comprises a reversible motor mounted to the housing and connected to the pad holder by means of a threaded output shaft which supports a lifter arm rotatably connected to the pad holder. Rotation of the threaded shaft in one direction or the other moves the lifter arm into which the shaft is threaded together with the pad holder and pad up or down relative to the floor. By observing the current draw of the drive motor, control of pad pressure may be achieved. The pad holder design provides a directed air flow into the housing to collect dust, dirt and debris generated by the buffing operation.

FIELD OF THE INVENTION 
The present invention relates to floor treatment machines and methods, and 
more particularly to an electric floor buffing machine in which the 
pressure between the buffing pad and the floor can be automatically 
adjusted by the user during operation of the buffing machine. 
DESCRIPTION OF THE PRIOR ART 
Conventional electric floor buffing machines operate at rotational speeds 
of from about 175 RPM up to about 2000 RPM. At high rotational speeds in 
the 1500-2000 RPM range, control of buffing pad pressure is especially 
important for several reasons. First, in order to obtain a high gloss 
finish, i.e., a "wet look" finish, on a previously waxed floor, especially 
when dry buffing, it is necessary to create sufficient friction to 
generate heat and actually melt the top layer of wax on the floor. The 
friction and the resultant heat generated is proportional to the 
rotational speed at which the buffing machine operates and the pressure 
the pad exerts on the floor. Obviously, a low speed machine will require a 
substantial pressure to create the same amount of heat as a high speed 
machine. On the other hand, in a high speed machine, a lower pressure is 
necessary to avoid straining the electric drive motor or causing it to 
draw excessive current. 
One solution for achieving a superior finish on a waxed floor is disclosed 
in U.S. Pat. No. 4,598,440, which is assigned to the assignee of this 
invention, and which discloses a high speed buffing machine with an 
X-shaped buffing pad for developing adequate friction and heat between the 
buffing pad and floor over a sufficient area without causing undue strain 
or excessive current draw on the drive motor. 
Another approach to controlling the pressure between the buffing pad and 
floor is disclosed in U.S. Pat. No. 4,845,798. In that patent, a pair of 
height adjustment wheels are mounted on opposite sides of the base by 
means of a pivoting axle. A manual adjustment mechanism is provided to 
vary the height of the wheels and thereby raise and lower the pad with 
respect to the floor. Other floor buffing machines with adjustment means 
for transport wheels are disclosed in U.S. Pat. Nos. 2,949,619 and 
4,358,868. 
Another conventional mechanism for adjusting pad pressure of a floor 
buffing machine is a manually adjustable caster or wheel on the front of 
the buffing machine housing for raising and lowering the front portion of 
the housing relative to the transport wheels. 
One of the disadvantages of the aforementioned prior art devices for 
adjusting the height of the buffing pad or pad pressure is that the 
buffing pad surface is tilted relative to the floor. Accordingly, pad 
pressure is applied unevenly to the floor with the greatest pressure being 
at the forwardmost edge portion on the pad surface. While a large pressure 
applied over a small area may not cause motor strain or overload, it may 
create excessive friction and heat in a localized area thereby causing 
burning of the wax and possible damage to the floor. 
Other prior art floor buffing machines rest on the buffing pad during 
buffing operations and in such machines pad pressure is a function of the 
weight of the machine and the degree of tilt applied to the machine by the 
operator during buffing. With such machines pad pressure is highly 
variable and cannot effectively be reduced below a minimum pad pressure 
resulting from the weight of the machine. Some machines of this type are 
provided with wheels which permit the machine to be tilted by pushing the 
machine handle downwardly to a position below the normal position for 
operating the buffing machine so that the buffing pad is raised off the 
floor for transporting the machine. 
The floor surfacing machine disclosed in U.S. Pat. No. 1,763,365 has a 
buffing pad with wings that apply a downward force on the pad proportional 
to the rotational speed of the pad. Pad pressure is not adjustable without 
varying the speed of the drive motor. 
It would be desirable to provide a floor buffing machine in which the 
buffing pad could be automatically raised and lowered relative to the 
floor surface by the operator from his operating position while 
maintaining the buffing surface of the pad parallel to the floor. Such a 
machine would provide the operator with complete control of pad pressure 
during buffing without having to tilt the machine or the buffing pad. It 
would also be desirable to provide a floor buffing machine in which 
buffing pad pressure can be automatically adjusted from a zero pressure, 
i.e., off the floor, to a maximum pressure in which the pad supports 
essentially the entire weight of the buffing machine. 
Advantageously, such a floor buffing machine would provide the machine 
operator with a method of automatically controlling the magnitude of pad 
pressure while the machine is operating and without having to turn off the 
machine to make a manual adjustment of pad height. 
SUMMARY OF THE INVENTION 
In view of the foregoing limitations and shortcomings of the prior art 
floor buffing apparatus, as well as other disadvantages not specifically 
mentioned above, it should be apparent that there exists a need in the art 
for a floor buffing machine that is capable of automatic pad pressure 
control by the operator during a buffing operation. 
The present invention fulfills that need in the art by providing a floor 
buffing machine having a machine base or housing supported on a plurality 
of wheels so as to be spaced a substantially fixed distance off the 
surface on which it is supported, e.g., a floor to be buffed. A handle is 
mounted to the housing for use by the operator to direct the buffing 
machine across a supporting surface and is foldable into a compact storage 
or carrying position. 
An electric drive motor having a driven splined shaft is mounted on the 
machine housing with the splined shaft extending downwardly through an 
opening in the housing. A hub having a splined bore is slidably mounted on 
the splined motor shaft and supports a buffing pad holder on which a 
buffing pad is removably attached. The hub and pad holder are movable up 
and down axially on the splined shaft by a pad lifter mechanism. The pad 
lifter mechanism comprises a lifter arm having two ends. One end of the 
lifter arm supports a pressed-in antifriction bearing in which the hub is 
rotatably mounted. The lifter arm extends transversely from the rotational 
axis of the hub and a threaded insert or threaded bore is provided in the 
other end of the lifter arm. The lifter mechanism further includes a 
reversible electric gear motor also mounted on the machine housing with 
its drive shaft also extending downwardly through an opening in the 
housing. The gear motor shaft is threaded, preferably with an acme-type 
thread, and threadably engages the correspondingly threaded insert or bore 
in the lifter arm. 
The reversible gear motor is controlled by the operator from a power switch 
mounted on the machine handle to rotate the threaded gear motor shaft 
clockwise or counterclockwise. In one direction of rotation of the gear 
motor shaft, the lifter arm is driven downwardly carrying with it the hub 
and pad holder which slide vertically downwardly along the splined shaft 
of the drive motor until the buffing pad attached to the pad holder 
engages the floor with the desired pad pressure. In the other direction of 
shaft rotation, the lifter arm is pulled upwardly to lift the hub and pad 
holder so that the buffing pad is raised to reduce pad pressure or move 
the pad completely out of contact with the floor. Limit switches set the 
uppermost and lowermost limits of travel of the lifter arm and thus the 
uppermost and lowermost positions of the pad holder. 
Since pad pressure is proportional to the electric current draw of the 
drive motor, control of pad pressure is advantageously achieved by 
providing a visual indication of motor current, e.g., by an ammeter 
provided with indicia calibrated in pad pressure magnitude with a maximum 
pad pressure indicated by a maximum current draw for the motor. 
Accordingly, during use of the buffing machine according to the method of 
the invention, the operator automatically controls pad pressure by 
energizing the gear motor to drive the pad holder downwardly until the 
visual indicator registers a desired level of pad pressure at which time 
the operator can deenergize the gear motor. When the buffing operation is 
completed, the gear motor can be energized to raise the pad holder and 
buffing pad off the floor surface so that only the machine wheels engage 
the floor. 
The buffing machine of the present invention incorporates a number of 
additional advantageous constructional features. The housing is preferably 
molded in one piece of a urethane polymer material loaded with 10-15% by 
weight of glass microspheres to provide a light weight and resilient, yet 
high strength, support for the buffing machine components. A prototype of 
the embodiment of the buffing machine described herein weighs less than 60 
lbs. The design of the housing and the foldable handle is such that the 
buffing machine can be stored in any one of three stable positions with 
the buffing pad off the floor surface. The foldable handle has two unique 
pivot joints which are easily operable to fold the handle over the housing 
into a compact package for shipping, transporting and storage. A lifting 
handle is provided on the foldable handle to permit the machine to be 
manually lifted and carried when necessary. 
The buffing machine is provided with a unique pad holder and buffing pad 
combination although other types of pad holders may be used with the 
buffing machine. For example, the X-shaped pad and pad holder disclosed in 
U.S. Pat. Nos. 4,598,440; 4,701,970; and 4,739,534 assigned to the 
assignee of this invention, and incorporated herein by reference, may be 
used with the buffing machine of this invention. 
The machine housing includes a receptacle for a dust nozzle and dust bag 
for collecting dust generated in the buffing operation. The dust bag is 
readily accessible for periodic emptying through a hinged cover on the top 
of the housing. The preferred wheel configuration for supporting the 
housing comprises four wheels, including two rear wheels on a fixed axle 
and two swivel wheels or casters mounted on the front of the housing. 
Advantageously, the drive motor and reversible gear motor are mounted on a 
removable mounting plate so that the entire motor assembly may be removed 
from the housing. Both motors are also independently mounted to the 
mounting plate so that each motor may be removed from the mounting plate 
independently of the other motor. 
The pad holder is a shaped substantially circular plate molded of a high 
impact ABS polymer material. The pad holder is formed with channels and 
openings for directing air flow through the buffing pad and into the 
housing above the pad holder. This air flow collects dust from the floor 
buffing operation and carries it into the dust nozzle and dust bag mounted 
in the housing receptacle. 
With the foregoing and other advantages and features of the invention that 
will become hereinafter apparent, the nature of the invention may be more 
clearly understood by reference to the following detailed description of 
the invention, the appended claims and to the several views illustrated in 
the attached drawings.

DETAILED DESCRIPTION OF THE INVENTION 
Referring now in detail to the drawings, there is illustrated in the 
perspective view of FIG. 1 the floor buffing apparatus of the present 
invention which is designated generally by reference numeral 10 and which 
is shown without a motor cover in place. Apparatus 10 comprises a base or 
housing 12 preferably molded in one unitary structure of a urethane 
polymer material filled with 10-15% by weight of glass microspheres. An 
electric drive motor 14 is mounted to a mounting plate 15 which is, in 
turn, affixed to the housing 12. The output shaft of motor 14 is directly 
connected to a buffing pad holder and buffing pad (not shown) supported 
beneath the housing 12. 
Electric drive motor 14 may be any suitable electric motor for the intended 
purpose, such as a 1.5-2.0 hp DC motor. A preferred motor according to the 
present invention is a 1.5 hp DC motor made by Ohio Electric Motors, 
Barnardsville, N.C. under the designation Model No. A-183270X9190 and 
having a splined output drive shaft. This motor operates at about 2000 RPM 
from a standard 110 volt residential or commercial power source and draws 
a full load current of about 15 amperes. A reversible gear motor 13 is 
mounted to mounting plate 15 to the rear of drive motor 14 for a purpose 
to be hereinafter described. 
The floor buffing apparatus 10 is maneuvered about by means of a foldable 
handle 16 having three major components, a fixed lower handle portion 18, 
a foldable intermediate handle portion 20, and an upper control handle 
portion 22. One end of the lower handle portion 18 is rigidly affixed to 
the housing 12 and the other end thereof is pivotally connected to the 
intermediate handle portion 20 by means of a first pivot joint 24 having 
two operative positions, the upright or operating position shown in FIG. 1 
and the folded position shown, for example, in FIG. 2. The control handle 
portion 22 is pivotally connected to the upper end of the intermediate 
handle portion 20 by means of a second pivot joint 26 which is angularly 
adjustable to any angular position relative to handle portion 20 within an 
arc of about 270.degree.-300.degree.. 
FIGS. 2-6 illustrate the details of the construction and operation of the 
floor buffing apparatus 10 of the present invention. Referring first to 
FIG. 2, the apparatus 10 is shown with the handle 16 in its folded 
condition. The housing 12 of apparatus 10 is rollably supported at a fixed 
distance above a floor F by means of a pair of fixed axle rear wheels 28 
(only one shown) and a pair of front swivel wheels or casters 30 (only one 
shown) which are affixed to the housing 12 in molded-in recesses. The 
lowermost end of the lower handle portion 18 is located in a molded-in 
recess 32 in the housing 12 and is fixedly secured in place by a pair of 
fasteners, such as machine bolts 34 and nuts 36. A lifting handle 38 is 
affixed by bolts 39 to the rear side of handle portion 18 for a purpose to 
be described. Shown in phantom lines in FIG. 2 is a molded plastic motor 
cover 19 which encloses the motors 13, 14 and is pivotally mounted to 
handle portion 18 by a pivot shaft 21. Motor cover 19 is preferably 
provided with slots (not shown) for allowing cooling air circulation about 
the electric drive motor 14 and gear motor 13. 
Mounting plate 15 is removably fixed to the upper surface of the housing 12 
by means of fasteners 40 and the bolts 34 and nuts 36. Drive motor 14 and 
gear motor 13 are secured to mounting plate 15 by bolts 42 which are 
accessible via clearance holes 44 from the underside of housing 12. This 
fastening arrangement advantageously permits the mounting plate 15, 
together with the motors 13, 14 to be attached to and removed from the 
housing 12 as a unitary assembly, and also permits each motor 13, 14 to be 
removed and replaced independently of the other motor and the mounting 
plate 15. 
Drive motor 14 has a splined output shaft 46 which extends through aligned 
openings 48 in the mounting plate 15 and housing 12. In a similar manner 
the gear motor 13, which includes a gear reducer 50, has a threaded output 
shaft 52 which extends through aligned openings 54 in the mounting plate 
15 and housing 12. Preferably, gear motor 13, and gear reducer 50 is a 
reversible 20 lb.-in. AC motor/gearbox combination manufactured by Molon 
Motor & Coil Corporation, Rolling Meadows, Ill. 60008 under the 
designation QHM-5063-X. Motor 13 is operable from a 110 volt AC source and 
the output shaft 52 of motor 13 is threaded with a 5/8 inch-8 acme thread. 
The hub assembly 56 of a pad holder is mounted on splined shaft 46 for 
sliding vertical (axial) movement and is vertically supported for 
rotatable movement with shaft 46 by a pad lifter mechanism comprising a 
lifter arm 58 supported in cantilever fashion by the threaded shaft 52 of 
gear motor 13. Lifter arm 58 is preferably cast of aluminum or an 
aluminum-zinc alloy, but may be made of other suitable materials, 
including metallic materials such as steel or plastic materials. 
The operation of the pad lifter mechanism can be best understood by 
referring to FIGS. 5 and 6. The pad holder hub 56 comprises a splined hub 
60 having an upper cylindrical portion 60a provided with a pair of annular 
grooves 60b and a lower hexagonal portion 60c also provided with annular 
grooves 60d. The lower hexagonal portion 60c of the splined hub 56 has a 
plastic hub insert 62 molded thereon. A pad holder mounting ring 64, made 
of a relatively rigid plastic material, such as nylon, is encapsulated 
with the hub insert 62 with a resilient polyurethane connecting part 66. 
Mounting ring 64 is provided with holes 68 for securing a suitable pad 
holder to the hub 56, such as, for example, the pad holder shown herein in 
FIGS. 15-16. Of course, other pad holders may be secured to the mounting 
ring 64, such as the X-pad holders described in U.S. Pat. No. 4,701,970 
assigned to the assignee of this invention or the pad holder described in 
copending U.S. patent application Ser. No. 07/820,003 filed Jan. 13, 1992, 
and also assigned to the assignee of this invention. 
The upper cylindrical portion 60a of splined hub 60 is pressed into the 
inner race 70 of an antifriction ball bearing 72 and is secured therein by 
retainer rings 74 inserted in grooves 60b. Bearing 72 is pressed into a 
bore 76 in one end of lifter arm 58 such that the hub assembly 56 is 
rotatable with shaft 46 relative to the lifter arm. The other end of 
lifter arm 58 is provided with a bore 78 for receiving a pressed-in steel 
insert having an internal bore provided with an acme thread 80 
complementary to the thread on shaft 52. 
The pad lift mechanism including lifter arm 58 shown in solid lines in 
FIGS. 2 and 5 depicts the uppermost position of the pad holder hub 56 in 
which the pad holder and buffing pad are raised above the floor F in 
non-contacting or spaced relation thereto. The position of the lifter arm 
shown in phantom lines 58' in FIGS. 2 and 5 and the mounting ring 64' in 
FIG. 2 depict the lowermost position of the pad holder hub 56 and pad 
holder mounting ring 64. In the lowermost position of hub assembly 56, a 
buffing pad 65, partly shown in phantom lines in FIG. 2, will be in 
operative, contacting relation with the floor F. 
Operation of the reversible gear motor 13 in one direction or the other 
drives the threaded insert 79 upwardly or downwardly as shown by 
double-headed arrow 82 in FIG. 5. This up and down movement of the insert 
79 drives the lifter arm 58 and hub assembly 56 up and down a 
corresponding distance as shown by the double-headed arrow 84 in FIG. 2. 
It has been found according to the present invention that, so long as the 
hub assembly 56 is rotated, even at a minimal RPM, e.g., 5-10 RPM, the 
splined hub 60 will not bind on splined shaft 46 when the lifter arm 58 is 
driven up and down by the threaded shaft 52 of gear motor 13. 
The gear motor 13 is controlled by a switch 85 mounted on upper handle 
portion 22 so as to be readily accessible to the machine operator during a 
buffing operation to vary the pressure of the buffing pad 65 on the floor 
F, or to raise the buffing pad off the floor F at the completion of an 
operation, or when transporting the apparatus to and from the work 
location. Advantageously, it is unnecessary to tilt the floor buffing 
machine of the present invention to raise the buffing pad off the floor as 
is required in many prior art machines. Tilting of the prior art machines 
is usually accomplished by pushing down on the handle and holding it at 
lower height, making it difficult and awkward for the operator to 
transport the machine in such tilted position. With the apparatus of the 
present invention, the operator may adjust the angle of the upper handle 
portion to a desired position most comfortable for the operator and keep 
the handle in that position for buffing and transporting. 
Referring again to FIG. 2, a pair of electrical limit switches 86, 87 are 
mounted to the underside of housing 12 for interrupting power to the gear 
motor 13 when the lifter arm 58 reaches positions of maximum upper and 
lower limits of travel. The upper and lower limits are set by contact 
elements 88, 89, respectively, which are connected to limit switches 86, 
87. 
FIG. 3 is a top view of the buffing apparatus 10 illustrating the location 
of two receptacles 90, 92 molded into the rear part of the housing 12. 
Each receptacle is provided with a cover 91, 93 each hingedly connected at 
the rear side thereof with a hinge (not shown) biased with a spring toward 
the open position. The covers 91, 93 are retained over the receptacles 90, 
92 by a suitable fastener, such as a quarter-turn fastener 94 (FIG. 2). 
Receptacle 92 houses some of thee electrical components (not shown) of the 
apparatus. Receptacle 90 contains a dust nozzle 95 and dust bag 96 which 
are illustrated and described in greater detail hereinafter in connection 
with FIGS. 13 and 14. 
FIGS. 7 and 8 illustrate the first or handle lock pivot joint 24 between 
the fixed lower handle portion 18 and the intermediate handle portion 20. 
The handle lock pivot joint 24 comprises two main elements, namely, the 
handle lock pivot socket 98 and the handle lock pivot ball 100. Handle 
portion 18 is fitted into a rectangular receptacle 102 of pivot socket 98 
and is secured therein by a pair of fasteners such as bolts and nuts 104. 
Handle portion 20 is slidably fitted into a rectangular receptacle 106 in 
pivot ball 100 and is secured therein by a pair of bolts and nuts 108. A 
pair of pivot means comprising a pair of pivot sleeves or bushings 110, 
111 extend through aligned openings in pivot socket 98 and pivot ball 
100/handle portion 20. Bushings 110, 111 are retained in place by threaded 
bolts 112 and nuts 114. Although the pivot means may be in the form of a 
single pivot pin passing through all aligned openings and retained therein 
by retainer rings or the like, the pivot bushings 110, 111 and retaining 
bolts 112 and nuts 114 are preferred so as to maintain a clear 
throughpassage along the hollow handle portions 18, 20 for the free 
passage of electrical wiring through the handle. 
As best seen in FIG. 7, pivot socket 98 has two pair of recesses 116, 118 
into one or the other pair of which handle lock levers 120 are resiliently 
biased by springs 122. Levers 120 are slidably disposed in rectangular 
cutouts or guideways 124 on opposite sides of pivot ball 100 and are each 
retained in a respective guideway 124 by a pair of screws 126 threaded 
into handle portion 20 and extending through longitudinal slots 128 in 
levers 120 as best seen in FIG. 8. Levers 120 are preferably molded of a 
plastic material, such as nylon, with projections 130 extending outwardly 
therefrom. 
In the position shown in FIGS. 7 and 8, the handle lock pivot joint 24 is 
set in its erect or operating position shown in FIG. 1 with the levers 120 
engaged in recesses 118. To pivot the joint 24 and fold the handle 16 to 
the position shown in FIG. 2, the levers 120 are both manually grasped by 
the projections 130 and lifted in the direction of arrow 131 (FIG. 7) to 
the position shown by phantom lines 132 (FIG. 8) to thereby disengage the 
levers 120 from recesses 118 and compress springs 122. Handle portion 20 
is then pivoted counterclockwise as seen in FIG. 2 about pivot pin 110 
until the ends of levers 120 bear on the arcuate surfaces 134 of pivot 
socket 98 under the force of springs 122. When the levers 120 are aligned 
with recesses 116, springs 122 urge the levers into recesses 116 and lock 
the handle portion 20 relative to handle portion 18 in the position shown 
in FIG. 2. 
As best seen in FIG. 7, the curved end surface 101 of the pivot ball 100 is 
enclosed by the curved rear portion 99 of pivot socket 98 over the entire 
angular movement of the handle portion 20. Advantageously, this 
construction eliminates any pinch points that might otherwise exist 
between the pivot socket 98 and pivot ball 100. 
FIGS. 9-12 illustrate the construction of the second pivot joint 26 between 
the intermediate handle portion 20 and the upper control handle portion 
22. Handle portion 22 is preferably molded of a plastic material with a 
pair of arms 136 each of which is connected to handle portion 20 by a star 
lock pivot 138, the construction of which is best shown in FIG. 10. Each 
pivot 138 comprises a pair of star lock elements 140 (FIG. 12) made of 
aluminum, an aluminum alloy or steel and having a plurality of radial 
teeth 142 with a triangular cross-section such that when the teeth 142 of 
two star lock elements 140 are interengaged as shown in FIGS. 9 and 10, 
the pivot joint 26 is prevented from pivoting movement. When the teeth 142 
are substantially disengaged, the star lock elements can be rotated 
relative to one another. 
The star lock elements 140 are provided with a central through bore 144 and 
an anchoring member 146 having a hexagonal cross-section (FIG. 11) and an 
annular groove 148. Star lock elements 140 are molded in place in the 
plastic arms 136 of handle portion 22 such that each anchoring member 146 
with its hexagonal cross-section and annular groove 148 is rigidly affixed 
in a respective arm 136. Similarly, the anchoring members 146 are inserted 
in circular bores 150 (FIG. 11) on opposite sides of the handle portion 20 
so as to leave spaces for welds 152 between the hexagonal cross-section of 
member 146 and the circular bore 150 to facilitate welding of the star 
lock element 140 to the handle portion 20. 
With the two pair of star lock elements 140 molded in the arms 136 and 
welded in the handle portion 20, the bores 144 of the elements 140 are 
aligned and a sleeve bushing 154 is inserted into the bores 144. A 
threaded pivot screw 156 is inserted through the sleeve bushing 154 and 
into a knurled knob 158 having a female threaded steel insert 160 molded 
therein. 
Those skilled in the art will appreciate that when the knobs 158 are 
loosened or unthreaded, the resiliency of the arms 136 will permit the 
teeth 142 of the star lock elements 140 to disengage to some extent so 
that the handle portion 22 can be rotated about the axes of pivot screws 
156 to a desired angular position relative to handle portion 20, e.g., the 
position shown in FIG. 1. Then, the knobs 158 are manually tightened to 
the position shown in FIG. 10 to fully engage the teeth 142 and lock the 
pivot 138 against rotation. When it is desired to store the buffing 
apparatus 10, the handle portion 22 is positioned relative to the handle 
portion 20 as shown in FIG. 2 and the knobs 158 are tightened. 
With the handle 16 folded to its position shown in FIG. 2, the buffing 
apparatus 10 may be stored in this position with the buffing pad 65 raised 
off the floor F. The apparatus 10 may also be stored in the positions 
shown in FIGS. 18 and 19 resting either on the handle portion 22 and the 
front of housing 12 (FIG. 18) or on the pivot joint 24 and the rear of 
housing 12 (FIG. 19). In all three storage positions (FIGS. 2, 18, 19) the 
apparatus 10 is stable and the buffing pad is advantageously not under 
compression during storage, which compression could otherwise permanently 
deform it. Advantageously, the positions of FIGS. 18 and 19 take up less 
floor space than the FIG. 2 position. In the FIG. 19 position, the 
apparatus 10 is sufficiently lightweight (less than 60 lbs.) that it can 
be picked up by lifting handle 38 and carried to a desired location. 
Referring now to FIGS. 13 and 14, the dust nozzle 95 is formed as a 
funnel-like member having a downwardly inclined scoop plate 162 which 
scoops up air and dust generated by the buffing pad and pad holder during 
a buffing operation and passes it through a converging nozzle throat 164 
which is angled off axis from the nozzle inlet flange 166 to the nozzle 
outlet flange 168 to conform to the angle the receptacle 90 (FIG. 3) is 
inclined relative to the longitudinal axis of the apparatus 10. Dust bag 
96 is releasably affixed to outlet flange 168 of the nozzle 95 by a 
resilient band 170, such as a rubber O-ring. 
The nozzle inlet flange 166 is beveled at different angles A, B (FIG. 14) 
along its vertical edges 172, 174, respectively. In addition, the vertical 
edges 172, 174 are tapered from top to bottom as shown in FIG. 13. The 
beveled and tapered edges 172, 174 advantageously constrain the nozzle 95 
to fit into the receptacle 90 in only one orientation as shown in FIG. 3. 
Referring to FIGS. 1 and 3, the method of operation of the apparatus will 
be described. Electrical power from a 110 volt AC source is provided to 
the apparatus 10 by an electrical cord 11 which enters the handle portion 
22 and directs electrical power to the various electrical components by 
electrical wiring (not shown) in a manner well known and understood by 
those skilled in the art. Electrical wiring passes down the hollow handle 
portions 18, 20 and pivot joint 24 and into receptacle 92 from where it is 
connected to the drive motor 14, gear motor 13 and limit switches 86, 87. 
An ammeter 180 is mounted on handle portion 22 for measuring the magnitude 
of the current draw of the drive motor 14. The ammeter reading is a 
measure of the load on the motor 14 and is thus proportional to the 
pressure the buffing pad exerts on the floor F. If desired, the ammeter 
may be calibrated in pad pressure, e.g., low, moderate, heavy, etc., and 
may also indicate a motor overload condition. 
Assuming the apparatus 10 is configured as shown in FIG. 1 with the buffing 
pad raised above the floor F. Power from electrical cord 11 is directed to 
drive motor 14 when the operator grasps one or both of the levers 182 
(FIG. 3) and urges it rearwardly against the bars 184 of handle portion 
22. When drive motor 14 is energized and the buffing pad begins to rotate, 
the operator activates switch 85 to lower the buffing pad with gear motor 
13 and observes the reading on ammeter 180 until the desired current or 
pad pressure is reached, at which time he releases switch 85 and carries 
out the buffing operation. During the buffing operation, a reduction in 
pad pressure may signify pad wear or deterioration. Pad pressure can be 
increased by again activating switch 85 to lower the buffing pad further. 
At the end of the buffing operation, the operator activates the switch 85 
to raise the pad holder and buffing pad off the floor F. The buffing 
apparatus 10 may then be transported to storage and stored in any one of 
the three positions shown in FIGS. 2, 18 and 19. 
FIGS. 15-17 illustrate one preferred form of a pad holder and buffing pad 
for the floor buffing apparatus of the present invention, it being 
understood that other pad holders and buffing pads may be used with the 
apparatus. Pad holder 200 comprises a circular-shaped disk molded of a 
high impact ABS plastic material and has a diameter of about 20 inches. A 
central opening 202 is provided in the pad holder for receiving the pad 
holder hub assembly 56 (FIGS. 2 and 5). Hub assembly 56 is secured to pad 
holder 200 by means of fasteners extending through holes 204 in the pad 
holder 200 which are aligned with holes 68 in the mounting ring 64 of hub 
assembly 56. 
The surface of pad holder 200 shown in FIGS. 15 and 16 is the surface to 
which a buffing pad is attached, i.e., the lowermost surface. Any suitable 
attachment means for the buffing pad may be provided, such as the hooks of 
a hook-and-loop fastener of the type disclosed in the aforesaid copending 
U.S. patent application Ser. No. 07/820,003. For purposes of clarity, no 
pad fasteners are shown in FIGS. 15 and 16. 
The pad holder 200 is formed with two air intake channels 206 which direct 
a flow of air along the intake channels in the direction of arrows 208. 
(FIG. 16) when the pad holder 200 is rotated counterclockwise in the 
direction of arrow 210 (clockwise as viewed from above the pad holder). 
Each channel 206 extends somewhat spirally from the outer periphery 212 of 
the pad holder to an inclined surface 214 in which an air flow passage or 
opening 216 is provided. Air flow in the clockwise directions 208 passes 
through passages 216 and continues in a generally curved or circular 
horizontal path until the flow is deflected upwardly into the interior of 
housing 12 (downwardly as viewed in FIGS. 15 and 16) by the inclined 
surfaces 218 located about 75.degree. counterclockwise from the passages 
216. The air flow generated in this manner functions to draw loose dirt, 
dust and debris from the buffing operation up into the housing interior 
where the scoop plate 162 of dust nozzle 95 (FIGS. 4, 13 and 14) directs 
the same into the dust bag 96. Thus, the pad holder 200 effectively 
maintains the buffed floor area relatively free of dirt, dust and debris 
which might otherwise remain on the floor and possibly mar the high gloss 
finish on the floor. If greater air flow is required, additional flow 
passages 220 may be provided in inclined surfaces 222 to augment the air 
flow through passages 216. 
A preferred buffing pad 65 for use with the pad holder 200 is shown in FIG. 
17. Buffing pad 65 may be made of any suitable material and is preferably 
cut from a non-woven mat of rubberized, loosely-spun polyester fibers 
commonly used as a buffing pad material and readily attachable to the 
aforesaid hook-type fastener. The pad 65 also has a diameter of about 20 
inches and is provided with a central opening 224 which engages over the 
resilient urethane flange 63 as shown in FIG. 2 in phantom lines. The pad 
65 is also preferably provided with four equiangularly spaced holes 226. 
At least two of the diametrically opposed holes 226 are aligned with the 
flow passages 216 in pad holder 200 when the pad 65 is attached to the pad 
holder. The remaining two diametrically opposed holes 226 will be aligned 
with the additional passages 220 (if provided) in the pad holder 220. 
Holes 226 in the pad 65 are not essential, especially where a relatively 
porous buffing pad material is used. 
It will be appreciated by those skilled in the art that the floor buffing 
machine and method of the present invention provide a unique solution to a 
number of shortcomings of the prior art apparatus and methods. It will 
also be appreciated that this invention could be applied to other types of 
rotatable cleaning apparatus for floors, such as scrubbers, strippers, 
burnishers, polishes and the like. 
Although only preferred embodiments are specifically illustrated and 
described herein, it will be appreciated that many modifications and 
variations of the present invention are possible in light of the above 
teachings and within the purview of the appended claims without departing 
from the spirit and intended scope of the invention.