US2683884A

US2683884A - Floor polisher

Info

Publication number: US2683884A
Application number: US91980A
Authority: US
Inventors: Erhard O Kohl
Original assignee: Hoover Co
Current assignee: Hoover Co
Priority date: 1949-05-07
Filing date: 1949-05-07
Publication date: 1954-07-20
Anticipated expiration: 1971-07-20
Also published as: NL153245B; CH283364A; GB677475A; NL77469C; DE884075C

Description

y 1954 E. o. KOHL 2,683,884

FLOOR POLISHER Filed May 7, 19491 5 Sheets-Sheet l INVENTOR. Erhard Q [fa/ll ATTOHNE Y.

1954 E. o. KOHL 7 4 FLOOR POLISHER Filed May 7, 1949 3 Sheets-Sheet 3 Fig.3

y INVENTOR.

I [mm/0.1M!

Patented July 20, 1954 FLOOR POLISHER Erhard O. Kohl, Massillon, Ohio, assignor to The Hoover Company, North Canton, Ohio, a corporation of Ohio Application May 7, 1949, Serial No. 91,980

2 Claims.

This invention relates to floor polishers and more particularly to a dual brush polisher in which the brushes rotate in opposite directions.

The present invention is particularly concerned with the arrangement of the various parts of the complete assembly in order to provide a polisher having a very low center of gravity to give greater stability and ease of operation.

In polishers of the oppositely rotating brush type it is usual to drive the vertically extending brush shafts by worm gears on opposite ends of the shaft of a horizontally positioned motor. In the usual construction this positions the center of gravity of the assembly as a whole to one or the other side of a line connecting the center lines of the brush shafts which renders the polisher unstable in operation regardless of where the handle is attached.

Also when conventional motors, having the motors stator evenly distributed about the shaft axis, are used to drive the brushes the center of gravity of the entire assembly is so high that it further contributes to the unstability of the polisher in use.

According to one aspect of the present invention a unicoil motor is used with the major portion of the weight of the field located toward a line connecting the center lines of the brushes and away from the motor shaft axis so that the center of gravity of the entire assembly is located nearer to a line connecting the center lines of the brushes. The use of a unicoil motor also renders it possible to lower the concentrated weight of the stator downwardly so as to materially lower the center of gravity of the entire assembly.

Both of the foregoing features contribute materially to the stability of the polisher in use.

In order to further stabilize the action of the polisher of this invention in operation, the manipulating handle is pivoted to the main frame on the center line of the brushes and slightly below the center of gravity in the entire assembly so that the center of gravity of the assembly is positioned above and to the rear of the axis upon which the propelling handle is pivoted.

According to another aspect of the present invention a main casting is provided which forms a support for all of the working parts of the polisher including the propelling handle, the motor stator, the bearings for the motor rotor, the motor brushes, the headlight for illuminating the surface being polished, and the bearings for the brush shafts as well as gear housings for enclosing the worm gearing between the motor shaft and the brush shafts.

The main casting is made in two parts divided vertically midway between the axis of the brush shafts. The one part has locating means thereon for locating the laminations of the motor stator which may be bolted thereto as a semipermanent assembly whereby the motor rotor may be disassembled independently of the stator for purposes of repair, etc. by merely separating the two parts of the main casting.

According to another feature of this invention the main casting has falls extending upwardly therefrom which cooperate with downwardly extending ribs on the appearance housing to form a cooling air circuit whereby cooling air is drawn inwardly through louvers in the appearance housing by the cooling air fan, passes between the motor rotor and stator to keep the motor cool, passes upwardly through the fan chamber through a passage to a chamber housin the headlight, and is discharged through an opening in the appearance housing through which the light rays are projected.

Also, according to this invention, the cooperating ribs on the main frame and on the appearance housing form the fan chamber for the cooling air fan.

Other objects and advantages of this invention will become apparent as the description proceeds when taken in connection with the accompanying drawings in which:

Figure 1 is a perspective view of the polisher of this invention showing the arrangement of the parts and with the appearance housing raised upwardly to depict how it cooperates with the main casting to form the cooling air circuit;

Figure 2 is a plan view looking downwardly on the polisher of Fig. 1 and further showing the arrangement of parts; and

Figure 3 is a cross-sectional view taken on line 3-3 of Fig. 2 and looking in the direction of the arrows.

Referring to the drawings, the reference numeral [0 generally represents the main frame preferably formed of an aluminum casting and formed in two parts I I and I2 divided on a vertical plane I3 substantially midway between the axis of the brush shafts. The two parts are machined on their dividing plane and are detachably secured together, preferably by means of bolts I4.

Formed integrally with the main frame parts II and I2 are upwardly extending gear housings I5 and I6. Each of the housings I5 and I6 is bored to receive a hearing I! for the vertically extending shafts I8 which rotatably support a pair of opposite rotating polishing brushes 9 and 20 which are secured to the lower ends of the shafts IS in any suitable manner.

Keyed to the upper ends of each of the shafts I8 is a worm gear 2| which meshes with worms 22 formed on the opposite ends of a motor shaft 23.

The worms 22 and the gears 2| are so formed that rotation of the shaft 23 will rotate the brushes l9 and 26 in opposite directions.

The gear housings l5 and I6 also include integral supports for the bearings for the shaft 23 as indicated at 25 and 26 and are provided with closure plates 21 and 26 to retain a suitable lubricant within the housings.

The shaft 23 carries the motor rotor comprising the iron laminations 29, winding 30, and the commutator 3|. The part |2 of the main frame also includes an integral upwardly extending protuberance 32 having a substantially circular undercut flange 33 for receiving the field laminations 34. The field laminations 34 are semipermanently secured within the circular flange 33 by bolts 35. The outer surfaces of the pole pieces 36 of the lamination 34 are in the form of a segment of a circle whereby the circular flange 33 will properly position the poles 36 relative to the rotor laminations 29.

As shown in Fig. l the yoke 31 of the laminations 34 is extended forwardly and across a line connecting the center lines of the brush shafts I8. A single field coil 38 surrounds the yoke 31 of the field laminations 34 to provide the necessary motive power.

The main casting It being of aluminum and the parts of the motor being iron and copper, it is obvious that a large proportion of the weight is concentrated in the motor. By making the motor of the unicoil type and extending its yoke across a line connecting the center lines of the brush shafts it is obvious that the center of gravity of the entire assembly will be shifted towards the axes of the brushes.

It is also obvious that by the use of a unicoil motor the concentrated weight of the motor will be lowered in relation to the other parts.

The right hand half l2 of the main frame also has integral supports 40 having aligned bores for receiving the motor brush holders 4| to properly position the motor brushes 42 relative to the commutator 3|.

. The main frame l also includes integral protuberances 45 for supporting the pintles 46 for the propelling handle bail 41. As shown, the pintles 46 .are positioned on a line connecting the center lines of the brush shafts [8, below the center of gravity of the assembly as a whole so that the center of gravity of the assembly is positioned upwardly and rearwardly of the axis of the pintles.

Integral with the half ll of the main casting and extending upwardly therefrom is a rib 50 which, as will presently appear, forms a portion of the enclosing casing for a cooling fan suitably secured to the motor shaft. Secured, in any suitable manner, to the half H on the main frame and extending parallel to the rib 56 is a plate 52 having an opening 53 forming the eye for the fan 5| as clearly shown in Fig. 3.

It is to be noted that the plate 52 stops short of the forward end of the rib 50 and that the rib 56 includes a right angled extension 54 which interfits with the rear edge of the plate 52 to close off the rear end of the fan housing.

Extending at right angles from the forward end of the plate 52 is an upwardly extending reflective plate 55 which is secured to the main frame II! in any suitable manner. Secured to the base of plate 55 forwardly thereof is an electric socket 56 for supporting a headlight 51 in front of the reflective surface of the plate 55.

A dome-shaped streamlined appearance housing generally indicated by the reference numeral 66 fits over the top of the main frame ID so as to hide the working parts of the polisher. The lower edge 6| of the housing 66 fits about the periphery of the main frame If! and is normally secured thereto in any suitable manner.

The housing 66 is preferably made of a thermosetting type of phenolic plastic. Extending downwardly from the dome of the housing 66 are integral ribs 52, 63, and 64. The ribs 62 and 63 cooperate with the rib 50 of the main frame and the plate 52 to complete the fan housing and also the forwardly extending passage 65 leading to the headlight chamber. The rib 64 cooperates with the plate 55 and with the sides of the housing to form a motor chamber on its rear side and a headlight chamber on its forward side.

The dome of the housing 60 is provided with louvers 66 (Fig. 3) to provide for the entrance of cooling air and the front side wall thereof is provided with an opening 61 which serves the dual function of providing an exit opening for the cooling air and an opening through which light rays are projected from the light 51 onto the surface being polished.

The handle bail 41 is of channel shape as shown and one leg thereof forms a housing for a conductor cord 68 leading from a switch in the handle (not shown) and being electrically connected to the motor and the light 51 in any suitable manner. The housing 60 is provided with an opening 69 (Fig. 3) adjacent one of the pintles 46 to provide for the entrance of the cord 68 into the motor chamber. As shown in Fig. 1 an upwardly extending rib 16 on the main frame |0 interfits with the housing 60 to close off the motor chamber from the headlight chamber and prevent recirculation of cooling air. The rib 16 is provided with a suitable notch to receive the conductor cords leading to the headlight 51.

The opening 69 is made large enough to provide for pivotal movement of the bail 41 about the pintles 46 without interfering with the cord 63. Any suitable latch mechanism may be provided for holding the handle in its vertical storage position when not in use. A furniture guard of any suitable character may encircle the periphery of the main frame l0.

During the operation the motor rotates the brushes l9 and 20 in opposite directions and rotates the cooling fan 5|. Cooling air is drawn into the motor chamber through the louvers 66, passes through the eye 53 of the fan, is discharged upwardly and forwardly through the channel 65, formed by the coacting ribs on the main frame it and the housing 66, passes into the light chamber and exits by the opening 61.

The coacting ribs on the main frame and housing prevents the recirculation of cooling air and insures that it passes over both the motor and the headlight to cool them.

If it is desired to remove the motor rotor for repair or replacement it is unnecessary to disturb the assembly of the motor stator with the frame. The bail 41 is removed by removing the pintles 46, housing 60 raised upwardly, and the two halves and I2 of the main frame separated by removing the connecting bolts. Thereafter the motor rotor can be slid horizontally out of the stator.

From the foregoing it can be seen that this invention provides a floor polisher having a compact arrangement of parts utilizing a unicoil motor whereby the center of gravity of the unit is shifted forwardly and downwardly to give greater stability, in which all of the parts are supported from the main frame in such a manner that the motor rotor can be disassembled from the stator Without disturbing the assembly of the motor stator with the frame and in which the appearance housing and main frame cooperate to form cooling air ducts for leading cooling air over both the motor and the headlight.

While I have shown and described but a single embodiment of my invention it is to be understood that this embodiment is to be taken as illustrative only and not in a limiting sense. I do not wish to be limited to the specific structure shown and described but to include all equivalent variations thereof except as limited by the scope of the claims.

I claim:

1. In a floor polisher, a main frame, a pair of spaced vertical axis shafts rotatably carried by said frame, a shaft rotatably supported by said main frame on a horizontal axis to the rear of a line connecting the axes of said vertical axis shafts, gearing drivingly connecting the ends of said horizontal axis shaft with the upper ends of said vertical axis shafts to drive them in opposite directions upon rotation of said horizontal axis shaft, a motor rotor carried by said horizontal axis shaft for rotating it, and a U-shaped unicoil motor stator carried by said frame with its pole pieces embracing said rotor and its yoke and. coil extending across the line connecting the axes of said vertical axis shafts whereby the center of gravity of the polisher lies between the axis of the horizontal axis shaft and the line connecting the axes of said vertical axis shafts.

2. In a floor polisher according to claim 1 including a manipulating handle pivoted to said main frame on an axis passing through the axes of said vertical axis shafts and lying below the center of gravity of the assembly whereby the center of gravity of said assembly lies above and to the rear of the pivotal axis of said handle.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,622,166 Schultz Mar. 22, 1927 1,820,482 Orth Aug. 25, 1931 1,854,638 Woods Apr. 19, 1932 1,877,951 Norris Sept. 20, 1932 1,927,225 Woods Sept. 19, 1933 1,927,227 Woods Sept. 19, 1933 1,928,246 Brinker Sept. 26, 1933 1,937,287 McGee Nov. 28, 1933 2,119,386 Holm-Hansen May 31, 1938 2,258,165 Sassano Oct. 7, 1941 2,300,138 Steele Oct. 27, 1942 2,340,379 Hahn Feb. 1, 1944