US3445877A - Polishing machine - Google Patents

Description

Mi)" 27,1969 H. E. srour 3,445,377

POLISHING MACHINE Filed July 26, 1966 Sheet ors I .6 i v .2

5. o I 130/ J w FIG.2

AIQ'TORNEYS POLISHING MACHINE Filed July 26, 1966 Sheet 2 Ora 7 7' I 58 66 J7) I i INVENTOR. HARRY E; STOUT BY 7 74 mzmOuz ATTORNEYS May 27, 1969 H. E. s'rou-r 3,445,877

POLISHING MACHINE Filed July 26, 1966 5 of 3 Sheet INVENTOR. HARRY E. STOUT 247M, Wk,

ATTORNEYS I United States Patent Office 3,445,877 Patented May 27, 1969 US. CI. 15-98 7 Claims ABSTRACT OF THE DISCLOSURE A power-driven bufiing machine is provided with a drive mechanism which produces a rotating oscillating action of a butfing head to produce a smooth, unstreaked finish on the worked surface. The drive mechanism includes a crank arm connected to the motor drive shaft, a pivotal connection between the buifing head and the crank arm eccentric thereto, resilient elements such as coil springs connecting the head to the housing to limit the rotary movement of the head and magnetic elements, in the preferred mode, which cyclically impart an angular thrust to the head causing it to oscillate back and forth about its eccentric axis.

This invention relates generally to power-driven polishing machines and more particularly is directed towards a new and improved driving mechanism for powerdriven polishing machines and the like characterized by a unique rotating oscillating action which produces a superior finish when bufiing a waxed surface, for example.

There are available a great variety of polishing machines for brushing, bufling or otherwise finishing hard surfaces such as floors, automobile bodies and the like. Most of these machines employ rotary bufling heads onto which a circular pad or brush is attached for rotation by means of an electric motor. Other machines may employ two counter-rotating heads while still others employ eccentrically mounted rotary heads. In any event, the machines presently available are not entirely satisfactory from the standpoint of the finish produced, ease of handling, cost and mechanical simplicity. Most machines of this type leave a streaked or whorled finish which is objectionable particularly on automobiles.

Accordingly, it is an object of the present invention to provide improvements in power-driven bufling machines.

Another object of this invention is to provide a powerdriven bufiing machine which will have a buffing action similar to hand polishing and yet capable of producing a superior finish at a high rate of speed.

A further object of this invention is to provide a buffing machine or simple, low-cost design and one which is easily manipulated over the working surface.

Yet another object of this invention is to provide a buffing apparatus adapted to produce a smooth, even finish on the working surface.

More particularly, this invention features a buffing apparatus, comprising a motor having a rotary drive shaft, a bufiing head eccentrically connected to the drive shaft and pivoted about an axis parallel to the shaft, and control means operatively connected to the head and to the motor for producing an angularly limited oscillating motion of the head about one axis as the drive shaft rotates the head eccentrically about another axis.

This invention also features novel arrangements for oscillating the head about its axis.

However, these and other features of the invention, along with further objects and advantages thereof, will become more fully apparent from the following detailed description of preferred embodiments of the invention,

with reference being made to the accompanying drawings, 1

in which:

FIG. 1 is a view in perspective of a buffing machine made according to the invention,

FIG. 2 is a sectional view in side elevation of the FIG. 1 apparatus,

FIG. 3 is a cross-sectional view taken along the line 33 of FIG. 2,

FIG. 4 is a schematic diagram showing the movement of the head during operation of the machine,

FIG. 5 is a top sectional view of a modification of the invention,

FIG. 6 is a fragmentary sectional view in side elevation showing another modification of the invention,

FIG. 7 is a cross-sectional view taken along the line 77 of FIG. 6.

FIG. 8 is an exploded perspective view of the modification shown in FIGS. 6 and 7, and,

FIG. 9 is a top sectional view of a further modification of the invention.

Referring now to the drawings and to FIGS. 1 through 4 in particular, the reference character 10 generally indicates a hand-operated bufiing machine, comprising a housing 12, which may be a bell-shaped metal casting, for example, provided with a handle :14 and mounting an electric motor 16. The motor is drivingly connected to a polishing head 18 by means of a drive mechanism 20 to be described more fully below.

Typically, the polishing head 18 comprises a circular metal pan 22 to which is attached a resilient stratum 24, of rubber or the like and over which is attached a suitable bufiing face of wool fleece 25, for example. Obviously other buffing finishing materials such as a brush, for example, may be attached to the head assembly and used in place of the fleece.

The motor .16 is provided with a conventional drive shaft 26 extending from the lower end thereof and has attached thereto a crank arm. The arm 28 is formed with a central hub 32 having a vertical opening 30 to accommodate the shaft 26. A set screw 34 secures the crank arm 28 to the shaft 26 in fixed relation thereto.

The arm 28 has an extension 36 at right angles to the axis of the shaft 26. This extension carries a stub shaft 38 which is eccentric to the motor drive shaft 26 and extends downwardly to connect to the circular pan 22 by means of a ball-bearing assembly 40. A smaller circular plate 42 is mounted centrally over the pan 22 and is fixed to the outer race of the ball-bearing assembly 42.

As best shown in FIGS. 2 and 3 angularly spaced tensioned coil springs 44 connect the plate 42 to the housing 12. As shown in FIG. 3 the springs 44 are arranged at intervals about the axis of the motor 26, with one end of each spring fastened to the inner wall of the housing 12 and the opposite end connected to the polishing head 18 by the upper edge of an annular wall 46 extending about the periphery of the plate 42. It will be understood that the head assembly 18 is thus restrained against full rotation about the axis of the stub shaft 38 although the springs 44 do permit limited angular movement about the eccentric axis.

The crank arm 28 is formed with a counter-balancing portion 48 extending to the left as seen in FIGS. 2 and 3 opposite the extension 36. The portion 48 not only serves to balance the eccentrically mounted head assembly but also carries a permanent magnetic member 50 such as the horseshoe magnet illustrated. The magnet 50 is mounted to the portion 48 with its pole faces extending outwardly in position to coact with a magnetically attractive member 52 of soft iron, for example, fixed to the plate 42 at the periphery thereof.

It will thus be understood that when the motor 16 is energized the shaft 26 will rotate about its axis rotating with it the crank arm 28. As the arm 28 rotates about the motor axis the bufling head 18 will be moved in a circular path but will not rotate by reason of the restraint imposed by the springs 44. Instead the head will oscillate clockwise and counter-clockwise about the eccentric axis of the stub shaft 38 under the influence of the rotating magnet 50 and the magnetically attractive member 52. Each time the crank arm portion 48 moves the pole faces of the fixed magnet 50 past the magnetically attractive member 52 it will pull the member 52 together with the bufiing head assembly clockwise as shown in FIG. 3. It will continue to pull the head clockwise until the force of the springs 44 becomes sufiicient to overcome the attraction between the magnet and the member 52, at which point the head assembly will snap back counter-clockwise to the extent permitted by the springs 44. On the next cycle of the crank arm 28 the magnetic devices will again cooperate to impart a clockwise movement to the bufiing head with the result that the bufiing head will continue to oscillate angularly about the eccentric axis of the stub shaft 38 to the extent permitted by the springs 44. The head assembly itself at the same time will be carried by the crank about a circular path determined by the extent of the ofiset between the motor shaft 26 and the stub shaft 38. A somewhat exaggerated motion pattern of the head is shown in FIG. 4 where it will be seen by the orientation of the arrows, that the head assumes the different angular positions in various positions of rotation of the crank arm. The pattern shown is similar in some respects to that produced by the motion of a hand wiping against the surface and oscillating back and forth about a central axis.

Referring now more particularly to FIG. there is shown a modification of the invention and in this embodiment the magnet 50 and magnetically attractive member 52 of the FIG. 1-3 device are replaced by an arched leaf spring 54 the ends of which are seated in cooperating slots 56 formed in the outer periphery of the counterbalance for a crank arm 28' similar to the crank arm 28 of the principal embodiment. The arched leaf spring 54 cooperates with a contoured bumper 56 formed on the inner side of an annular wall 46 for a plate 42'. The bumper 56 is formed with smoothly graded sides and is in position to engage the spring 54 as the crank arm 28' is rotated. It will be understood that as the crank arm rotates the spring 54 will come against the bumper 56. As the bumper and spring engage the crank arm through the spring 54 will pull the head assembly 18 clockwise to the extent permitted by springs 44. As the head 18 is carried clockwise the springs 44 will be tensioned and at a certain angular position their force will overcome the force of the spring 54 at which point the spring 54 will flatten out to a certain extent and ride over the bumper 56, releasing the head so that it snaps back counter-clockwise to be picked up again by the spring 54 during the next cycle. The resulting action is identical to the action of the principal embodiment, the head being oscillated angularly about the offset axis as the entire assembly is carried in a circular path by the rotating crank arm.

Referring now more particularly to FIGS. 6, 7 and 8 there is illustrated another modification of the invention and in this embodiment a motor 16" having a drive shaft 26" rotates a hub 58 about a central axis. The hub 58 carries an eccentric stub shaft 60 which in turn carries a plate 62 to which a bufiing head 18" is attached. The plate 62 is attached to the stub shaft 60 through a ball-bearing assembly 64. The plate 62 also carries a follower 66 in the form of a fixed post mounted near the periphery of the plate 62 and extending in spaced parallel relation to the stub shaft 60. The follower 66, as shown in FIG. 6, extends upwardly to be received in an elongated slot 68 formed in one end of a crank arm 70. The opposite end of the crank arm 70 is pivotally fastened to the housing 12 as by means of a screw and bushing assembly 72. It will be seen that the stub shaft also extends through the slot 68 whereby rotation of the motor and hub 58 will cause the crank arm to oscillate back and forth about the axis of the screw and bushing assembly 72. This angular oscillation of the crank arm 70 will be transferred to the polishing head assembly 18" by means of the follower 66. This will produce a buffing action similarto that of the principal embodiment. In other words the polishing head will be carried as a unit in a circular path by means of the rotating hub but itself will not rotate. Rather it will be angularly oscillated, first clockwise and then counter-clockwise, to the extent of the olfset between the stub shaft 60 and the drive shaft 26".

Referring now more particularly to FIG. 9 there is illustrated a further modification of the invention. In this embodiment a motor 16" rotates a hub 74 through a drive shaft 26". The hub carries a stub shaft 76 to which is mounted a bufiing head assembly 18" by means of a ball-bearing assembly 78. A crank arm 80 is pivoted loosely to the housing 12" at the right-hand end as shown in FIG. 9 by means of a screw and bushing assembly 82. The center portion of the crank arm engages the drive shaft 26 by means of a ball-bearing assembly 84 which is eccentrically keyed to the drive shaft whereby rotation of the drive shaft 26" will cause the crank arm 80 to oscillate back and forth about the axis of the screw and bushing assembly 82. The opposite end of the crank arm 80 is provided with a follower 86 which extends into radial grooves 88 formed in a plate 90 forming part of the bufiing head assembly 18". The operation of the drive mechanism is similar to that of the FIGS. 6, 7 and 8 embodiment in that the head will be carried in a circular path as the head oscillates angularly about an eccentric axis.

The resulting finish provided by the bufiing machines described and illustrated above is characterized by smooth, even appearance without the usual streaks and whorls produced by conventional rotary buffers.

While the invention has been described with particular reference to the illustrated embodiments, it will be understood that numerous modifications thereto will appear to those skilled in the art. Accordingly, the above description and accompanying drawings should be taken as illustrative of the invention and not in a limited sense.

Having thus described the invention what I claim and desire to obtain by Letters Patent of the United States is:

1. A bufiing machine, comprising (a) a housing,

(b) a motor mounted to said housing,

(c) a drive shaft connected to said motor for rotation about a first axis,

(d) a crank arm fixed to said shaft,

(e) a buffing head mounted to said arm for rotation about a second axis spaced from and parallel to said first axis,

(f) restraining means connecting said head to said housing to limit the angular movement of said head about said second axis, and

(g) cyclical and positive acting coupling means between said head and said shaft for intermittently imparting an angular force on said head upon rotation of said shaft.

2. A bufling machine according to clai m1 wherein said restraining means comprises at least one resilient member.

3. A buffing machine according to claim 1 wherein said restraining means comprises at least one coil spring.

4. A buffing machine according to claim 1 wherein said coupling means includes magnetically attractive members mounted on said head and said arm.

5. A bufiing machine according to claim 1 wherein said coupling means includes a bumper and a spring cyclically engagable with one another, one of said bumper and said spring being mounted on said arm and the other on said head.

(f) resilient means connecting said head to said housing to limit the angular movement of said head about said second axis,

(g) cyclically actuated coupling means between said 5 6. A bufiing machine according to claim 1 wherein said restraining means comprises a second crank arm pivoted at one end to said housing and slidably and pivotally connected at the other end to said head at a point oil-center to said head, and said coupling means comprises a driving member eccentrically mounted to said drive shaft and slidably and pivotally connected to said second crank arm whereby said second crank arm will oscillate about said one end and said head will oscillate about said second axis.

7. A bufiing machine comprising (a) a housing, (b) a motor mounted to said housing, (c) a drive shaft connected to said motor for rotation about a first axis, (d) a crank arm fixed to said shaft, (e) a bufling head mounted to said arm for rotation about a second axis spaced from and parallel to said first axis,

head and said arm for cyclically imparting an angular force on said head about said second axis upon rotation of said shaft.

References Cited UNITED STATES PATENTS 2,721,427 10/1955 Dremel 5l-170.3

FOREIGN PATENTS 200,755 11/ 1958 Austria.

US. Cl. X.R.

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