US1901627A - Portable abrading and polishing machine - Google Patents

Description

March 14, 1933. T. F. BRACKETT PORTABLE ABRADING AND POLISHING MACHINE Filed Aug. 28, 1931 Patented Mar. 14, 1933 UNITED STATES TRACY F. BRACKETT, OF HIGHLAND PARK, MICHIGAN i ormuuarm ABRADING AND' roLIsHING 1vIn`e1zt11vr'.'A

Application filed August 2 8, 1931'. Serial .No.`559,99`3.

My invention yrelates to improvements in portable sanding and polishingmachines.

One `of the objects of my inventionisvto provide a portable machine which is par- 5 ticularly adaptable for operating on curved or irregular surfaces.

A further object is to provide a portable machine having an abrading or polishingY member which when applied tothe surface to ber treated, will conform itself tocurves or irregularities in the surface sov as to vhave a much greater area of uniform contact with the work than( is possible with the usual abrading and polishing Wheels.

Other objects of my invention will apf-` pear hereinafter.

Referring to the accompanying drawing Fig.v 1 is a viewl in elevation ofa portable abrading and polishing machine embodying my invention; Fig. 2 is a sectional view on the line 2-2 of Fig. l; l

Figs. 3, 4 and 5 are detail sectional views ofdifferent forms of abradingand polishing elements which can be used inconnection with my invention.

The usual abrading andi polishing wheels which are in common use are, of course` cir-V cular'in shape having only a very limited which is being treated, and the treating of an extended surface or aV surface greater than the area of contact is accomplishedby moving the work and the wheel relatively to each other. This area of contact is very limited evenl though wheels are made flexible or yielding. This is particularly true in treating curved or irregular surfaces. The usual wheel cannot reach all portions of these surfaces and the pressure is. notuniform throughout the areai'of' contact, making it very diiiicult to grind or polish the Work uniformly.

I propose to employ a flexible beltv or band having an abrading surface 'and maintained in'state of slackness or looseness whereby it will7 when placed' in contact with the work, adapt itself' to the curves or irregularities in the surface by conforming to the contour thereof. I accomplish this 'lby'usingf an' endiarea of Contact with the surface' ofthe work less` slack belt or band and. propelling this belt in 'the' line of itself in such manner that the; centrifugal force.v developed forces the belt the working surface of the'bel't against a1 considerable portion. of 'the' area' of` the 5 5 surface ofthe work.

y In the present lstructure a. suitable frame 1 Vis provided which supports the shafts 2' ofbelt'supp'orting'pulleys Sandwhich also servesasa suitable enclosure or housing for the driving chain 4 and sprocket wheels 7. The housing is. made iny two-sections, Fig. 2, which are joined togetherl around their periphery by the bolts 5 so that access mayy be obtained to'the interior' of the housing 65" when desired. The pulley y. shafts 2; are mounted in suitable bearings 6 formed in the `frame housing and each shaft has a sprocket-'wheel 7 for ther drive chain. Between the pulley shafts a suitable' electric 70 driving motor 8 is mounted. The motor hasV i a 'shaft 9fextending through a suitable opening in the wall of the housingy having at its end a pinion 10 in driving'engagementwith the chain, Fig.` 1.y Thisv drives the pulley shafts 2finthe samewdirection at the same speedy because the sprockets 7 are of ther samef size. The rear wallv of the housing has upwardly and downwardly extending flanges: 11 with vvertical slots 12 therein, and 80 screwsy 13 are passed through these slots and into the motor" .shell for clamping the motor shell: tothe frame. yThe slots 12 per mit the motor and its pinion 10=to-be adjusted relatively to the frame' for the pur- 85' pose ofadjusting the tension on the drive chain. Themotorishell has a downwardlyv extending. flangel which conforms tothe lowerflange 11 of the frame housing to pro-V vide forVv the lower clamping screw 13. While I- have shown` 'an' electric *motori attached tothe frame for drilving'the pulleys, it is obvious that a flexible .shaft may be used. The shaft may be attached tothe frame and connected' to the pinion 10v for 95 driving-J the chain. e

The structure shown is'intended as a portf able unit and is provided with suitable handles l5' for the operator.` OneA of these handlesis placed in alignment with each No Aslipping laterally off of the pulleys.

' purpose.

The pulley shafts 2 and the pulleysV mounted thereon extends considerably beyond the frame a sufficient distance so that' the framewill not interfere with the manipulation of the abradingbelt in rall directionsvwith'respect to the'work. VThe .beltV pulleys 3 are yspaced apartto provide space between them for the work'. rllhe pulleys have flanges 8 to prevent the belt from The belt A is endless and extends around. both pulleys to provide driving contactV with the gulle s.k lhe length of the belt is Greater. I :v ,a L o 'than it would be 1r stretched tightaround the pulleys so that the reaches or Vunsupy ported portions A can bow outwardly under Y the action of centrifugal force developed when'the belt is driven vwhen the working portion of the lowerY reach A is placed in ContactV with the surface ofv work to be treated, its flexibility permits ittoconform tothe surface of the work, this conformance being brought about by the centrifugal force developed in the belt. In Fig. l` an irregular curved surface is indicated by the dotted line B, and the manner in which the vbelt conforms to its surface is indicated by the dotted lines A. f

rlhe belt may be made up of several narrowfsections placed side by side or it may be a single piece of the proper width for the purpose. rlhe abrasive or polishing, material may be applied directly to the outer surface of the belt or it may be carried on a separate stripl?, Figs. 3, l and 5 and the strip 17 applied to the outer surface of the belt by stitching or any other well known method of applying abrasives to polishing implements.

Figs. 8, 1- and 5 indicate several .different types ofv abrasives. used in abrading Aand polishing work. In Fig. 3 the abrasive is lshown as a wire pile 18 on the fabric strip 17. ln Fig. fthe polishing surface shown has cloth polishing pads or loops 19 stitched at intervals 2O to the strip 17. kFigo shows the abrasive, such as emery or carborundum 21, applied to the strip 17. Y

In a portable uni" of this character ythe operator has almost universal movement lof the unit in placing the belt in contact with the work, and, due to the slackness and flexibilityof the belt it will readily adapt itself to this universal movement and conform itself to the curvesor irregularities of the surface which is being treated. The slack belt has a comparatively great area of contact with the surface being treated and the pressure on this surface will be practically uniform throughout the area thereof with the result much more uniform and efficient work can be performed at a much greater speed. Y

I am aware that changes and alterations may be made in the construction and arf housing, sprocketsfast on said shafts in said housing, an endless chain directed about said sprockets, mounting means on said housing intermediate said bearings, a driving motor, a sprocket on the shaft of'thermotor and meshed with saidA chain, means adjustably securing said motor on said mounting means whereby said motor maybe moved to tension said chain, said motor driving said chain to impart rotative-movement to vsaid shafts, flanged pulleys fast on the portions of said shafts extending beyondsaid hous-V ing, and an endless flexible belt directed about said pulleys and of greater length than required to be stretched tautaround the pulleys, said belthaving an abrading surface on the outer face thereof, said rbelt being bowed outwardlyby the centrifugal force developed during movement. imparted to the belt whereby the abrading surface on the bowed portion of the belt may be engaged with and conformed to a surface to be abraded. Y

2. In a device of the *Y class described-,a housing having fixed bearings therein, shafts journaled insaid bearings and disposed in spaced relation andextending beyond said housing, sprockets fast on said shafts in said housing, an endless chain directedabout said sprockets, mounting means on said housing intermediate said bearings, a driving motor, a sprocket on the shaft of the ,motor and meshed with said chain, flanges on said housing intermediate said bearings and extending transversely of the housing,` a Si' bracket kon the motor, means adjustably securing said bracket to said flanges to vary the position of said motor andthe sprocket on the shaft thereof to tension said chain,

said motor driving said chain to impart roii" tative movement to said shafts, anged pulleys fast on the portions of said shafts extendingibeyond said housing, an endless flexible belt directed about said pulleys'and of greater lengthV vthan required to ybe stretched taut around the pulleys, said belt having an abrading surface on the outer face thereof7 handles on said housing extending therefrom in alignment With said shafts, said handles being grasped to permit movement of said housing whereby a portion of the belt intermediate the pulleys bowed out- Wardly by the centrifugal force developed during movement imparted to the belt may be engaged With and conformed to a surface to be abraded.

TRACY F. BRACKETT.

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