US2193419A

US2193419A - Portable surfacing machine

Info

Publication number: US2193419A
Application number: US216004A
Authority: US
Inventors: Edward B George
Original assignee: Individual
Current assignee: Individual
Priority date: 1938-06-27
Filing date: 1938-06-27
Publication date: 1940-03-12
Anticipated expiration: 1957-03-12

Description

March 12, 1940. E. B; GEORGE 293419 4 PORTABLE suRFAcING MAcHmE Filed .June 27; 1938 ATTORNEY. r

Patented Mar. l2, 1940 UNITED STATES PATENT. OFFICE ron'rmn sUarAcma moms Edward B. George, Chica-ign, lll.

Appueeaon June ai, 193s. serial No. 216,004 s claims. (ci. :s1-rw) This invention pertains to surfacing machines of the portable type adapted for smoothing and finishing flat surfaces of wood or other material.

One of the purposes of my present -invention is to provide a machine of this character havinga speed reducing gearing between the electric rnotor andthe surfacing pad which will enable a relatively small motor to be used without danger of stalling the same if the operator should apply more than the requisite or .usuali amount of pressure to the tool.

Another object is to provide a. construction by which an accurate adjustment of the relative positions of the meshing gears may be attained by a simple adjustment made during the assembly ofthe apparatus and the provision of means for thereafter holding the gears against displacement from such adjusted position.

A further purpose is to provide a exible connection of novel construction between the motor frame and the surfacing pad which will absorb vibrations and permit the pad to rest atly upon kthe surface being treated irrespective of tilting movements of the motor frame.'

Another feature of the invention resides in a construction which permits the direct application of any desired amount of pressure from the motor frame to the pad without interfering with the operation of the driving mechanism.

A further feature is found inthe novel means employed for protecting the operating parts against grit particles and dust which cause rapid wear of the parts.

Still another feature'of novelty resides the structure by which the covering sheet for the pad is detachably secured in position.

Other objects and advantages of my invention will be readily appreciated as lthe same becomes better understood by reference to the following description when considered in connection with the accompanying drawing.

Referring to the drawing,

Fig. 1 is a vertical sectional view of a machine 'i embodying my invention, the upper portion being shown in. elevation:

' Fig. 2 is a sectional view ontheline 1 2 of Fig. 1:

A Fig. 3 is a sectional view on the line 3--3 of Fig. 1; and

Fig. 4 is a sectional view on the line l--I of Fig. 1. i

Referring to the drawing more in detail, ref-y' erence character 5 indicates the motorbase of the'ma'chine4 provided with an annular shoulder tover which rotatably ilts an adjusting sleeve 1 provided at its lower end with an eccentrically disposed annular 'shoulder 8 surrounding the shoulder 6 and at its upper end with a concentric annular shoulder 9. surrounding therdepending concentric annular shoulder il of the motor 5 motor case is equipped at itsv lower-end with a ,u

driving pinion il.

The upper face ofthe base 5 is recessedv to accommodate a ball-bearing i8 and the lower face is similarly recessed to receive anotherV ballbearing i9,.each bearing comprising the inner .and outer races and interposed balls as is usual 'in bearings of this type. g A shaft'20 journaled in these bearings has xedly mounted upon its upper end aninternalgear 2l adapted to mesh with the pinionV I1 and has threaded upon its lower portion a nut 22 which, through an interposed washer 23, holds'the bearings and sha-ft against displacement relatively to the motor base.

In order to insurevproper driving relation between the pinion l1 and the gear 2|, which will 8 enable these gears to run quietly and without undue wear, relative adjustment between these gears is provided by the adjusting sleeve 1 previously described. When the parts arebeing assembled, the,gear adjustment is effected by ro- 95 tation of this sleeve. Since the recess in the upper end of the sleeve surrounding the shoulderv ii is concentric with-the motor shaft and, therefore, with the pinion i1,"and the recess in its lower end surrounding the shoulder 6 of the base 40 5in which the shaft 20 carrying the internal gear 2| .is mounted is eccentric to the motor shaft, rotationof the sleeve 1 between vthe motor and its base will move the base in a straight. line relatively to the motor, thereby causing the gear 45 2i to approach or recede from pinion Il until the requisite relative positions of these interj meshing parts is attained., The downwardly disposed shoulder of sleeve 1 is provided with a series of closely positioned tapped openings for the re- 50 ception of the cap screws 24 extending through openings'inthe base 5. When proper adjustment of the gears has been secured, these cap screws are inserted and threaded home, thereby locking the base and sleeve together with thek Il gears in proper relation. The sleeve may be locked to the motor housing by any preferred means, such as one or more set screws (not shown) extending through the sleeve into engagement with the shoulder Il.

The lower end of shaft has fixed thereto by a'set screw 25, or otherwise, a lcrank arm 26 carrying a depending crank pin 21 upon which is snugly fitted the inner race 28 of a ball-bearing including the outer race 2.5i and the interposed balls 3|. Atransverselydisposed opentop guide,- way 32v is fixed tothe pad plate 33 and proportioned to loosely receive the 'outer race 29, the perimeter of which is curved on a vertical arc so as to provide a line contact withthe'sides of the guideway and permit tilting movements of the motor relative to the pad plate without'imposing strains upon the driving mechanism. 'The lower end 34 of the crank pin 211 is roundedasv shown, and hardened to provide a thrust surface against the opposed hardened bottom wall of, the f guideway, so that downward pressure -exerted upon the motor housing rectly to the pad.`

The pad plate is flexibly connected motor. base through a` pair of flexible U-shaped

members

35 and 36 rigidly secured by bolts or i otherwise to the pad and to the base. These members, preferably of fibrous composition, possess sufiicient resiliency to normally support the weight of the motor with the thrust end 34 of the crank pin free from contact with the bottom of the guide member 32. 'Ihe apparatus may be operated, therefore, merely with the weight of the motor Iapplied to the pa'd, but if additional pressure is desired, as is customary, such pressure exerted by the operator is transmitted directly through the crank pin to the pad plate. 'Ihe pressure thrust is, therefore, not, transmitted to the pad through the

flexible members

35 and 36, with the result that their resiliency and consequently rigidity is not increased and they are free to absorb the vibrations ofthe pad and prevent their transmission to the motor case.

This construction provides a smoother running machine and one freer from vibration than those in which pressure is applied to thepad. through any flexible connection, the rigidity of which varies with the amount of pressure applied.

'I'he pad itself, indicated by reference character 31, may be of any suitable resilient material attached to the plate 33, and the working face thereof is covered by a detachable covering such as sandpaper, emery cloth, or other fabric 38 which in the present instance islaid over the surface of the pad and its ends brought around the up-turned loops 39 and 4I of the plate. For the purpose of detachably holding the sheet 38 in. position, I employ a rectangular holding member 42 formed of resilient wire provided at one end with a roller 43. In applying the holder, the lefthand end viewing Fig. 1 is positioned at the base of the loop 4|, whereupon the 'other end is rolled down to the base of loop 39 into the position shown. The resiliency of the holder clamps the fabric between its ends and the bases of the loops, thereby securely holding the sheet in position.

In order to protect the driving mechanism from the abrasive effect `of dust and otherparticlesv produced by the operation of the machine, Ihave provided a boot 44, secured at its lower end around the guide 32,` and having its upper end in-tu'rned, 'as shown in Fig'. 1, and clamped to the maybe transmitted di- I with "the within considerable limits without departing from the essence of the invention as set forth in the following claims.y

Iclaim: i A, 1. In a surfacing machine, the combination of a'.v motor, a surfacing pad, a motor base flexibly connected to said pad, a driving shaft journaled that the structural details thereof may be varied in saidbase, driving connections between one end of said shaft and said pad, a gear wheel mounted p on the other end of said shaft, a motor shaft provided with a` pinion meshing with said gear Wheel, andan adjustable connection between the motor and said motor base whereby the relative position of said gear wheel and pinion may be adjusted. i

- 2. In a surfacing machine, the combination of a motor, a gear wheel fixed on the motor shaft,

a motor base, a shaft journaled in said base, agear .wheel fixed on said shaft and meshing with said first mentioned gear wheel, and an adjustable connection between said motor and said base for adjusting the relative positions of said gear wheels.

3. In a surfacing machine, the combination of a motor, a driving pinion on the motor shaft, a motor base, a shaft journaled therein, a gear wheel mounted on said last mentioned shaft, and an adjusting sleeve interposed between said motor and said base, said sleeve. being concentrically associated with the motor and eccentrically associated with the base to provide for relative adjustment between said pinion and gear wheel. 4

4. In a surfacing machine, the'cornbination of a motor, a pinion on the motor shaft, an adjusting sleeve rotatable concentrically with the motor shaft', a motor base rotatably associated with said sleeve and arranged eccentrically whereby rotation of saidsleeve will effect a transverse adjustment between the motor and said base, a`

shaft mounted in the base, a gear wheel on the shaft adapted t'o mesh with said pinion, a surfacing pad, and driving connections between said shaft and said pad.

5. In a surfacing machine, the combination of a surfacing pad, an upwardly opening guideway connected to said pad, a motor driven shaft provided at'its lower end with a crank pin disposed in said guideway, the lower end of said pin being tapered to ride upon the bottom of said guideway upon the lapplication of downward pressure upon said shaft, a motor connected with the shaft,

and flexible connections between the motor and l said pad, said connections being adapted to yield under downward pressure to permitthrust to be exerted upon the pad through said shaft.

6. In a surfacing machine, the combination of a pad provided with an upwardly opening guideway, a motor base, a shaft mounted in said base and provided at its lower end with a crank pin disposed in said guideway, a motor mounted vupon said' base and operatively connected with said shaft, and resilient connections between the motor base' and said pad. said connections being adapted to sustain 'the weight of the motor but to yield under downward pressure exerted upon the motor. to permit the transmission of said pressure to the pad through said crank pin.

7. In a surfacing machine, the combination of Aa motor base having a vertically disposed shaft rotatably mounted therein, a motor carried by the base and operatively connected with said shaft, a

crank pin mounted on the lower end of said shaft,`

a guide member into which said pinextends, a surfacing pad associated with said guideway to be actuated thereby upon rotation of said shaft, and a pair of U-shaped resilient connections between the pad and the motor base adapted to sustain the weight of the motor but adapted to yield under downward pressure exerted upon'the motor to permit the transmission of said pressurethrough said shaft and crank pin to said pad.

8. In' a 'surfacing machine, the combination of a surfacing pad, a guideway connected to said pad, a motor driven shaft provided at its lower end with a crank pin disposed in said guideway.

and adapted to engage the bottom of said guideway upon the application of downward pressure upon said shaft, a motor connected with the shaft and exible connections between the motor and pad adapted to yield under downward pressure so as to enable exertion of thrust upon the pad through said shaft.

EDWARD B. GEORGE.