CA2006366A1

CA2006366A1 - Sanding machine

Info

Publication number: CA2006366A1
Application number: CA 2006366
Authority: CA
Inventors: Nicholas T. Falzetti
Original assignee: Individual
Current assignee: Individual
Priority date: 1988-12-22
Filing date: 1989-12-21
Publication date: 1990-06-22
Also published as: WO1990006834A1; AU4808290A

Abstract

Abstract of the Disclosure A machine for sanding flat surfaces on workpieces is disclosed. The workpiece to be sanded is attached to a platen on the frame so that the workpiece surface to be sanded faces upwardly. A motor rotatably drives an abrasive sanding disc about a predetermined axis which is perpendicular to the flat workpiece surface. Similarly, a second motor rotatably drives the platen in the opposite rotational direction so that, when the sanding disc is moved against the flat workpiece surface, the sanding disc sands the flat surface. A lubricant, such as water, is supplied to the center of the sanding disc during the sanding operation.

Description

SANDING MRCHINE
: -Backqround of the ~nventlon I. ~ield of the Invention The prosent invent~on rel~tes to sandlng machine~
5 ~ and, more partlcularly, to a sandlng machlne which utlllzesabraslve disc~. II. De~crl~tion of the Prlor Art There are many different machlnlng appllcatlons in ; which a flat surf~ce on a workp~ece ~ sanded to obtain an ~lmost perfect flat ~urface. The workpiece can be made of any materlal, ~uch a~ metal, pls~tlc, glase, and the llke.
The mo~nting surface for an automotlve transmis~ion constltute3 one such applicat~on.
~It has been the prev~ou~ practlce to u~e belt 1~ z sanders in order to sand such ~uriace~. ~he8e belt sandecs use a closed loop ~anding belt whlch 1~ longitudin~lly drlven around two ~paced rollers. While the belt i~ drlven ~ around the rollers, the belt engage~ the workplece and - performs the sanding operation.
20 ~ Wh~le these prevlou~ly known belt sander~ have proven effectlve ln san~lng the workplece, they suffer from ¦ a number of dlsadvantage~. One such dlsadvantage 18 that - ~ the belt~ requlre frequent replacement. Such replacement 18 ~ not only expen~lve due to ~he cost of the sanding belt but ~ al~o relatively time consuming which results ln down time for the ~andlng machlne.
A ~urther di~adv~ntage of the~e prevlously known ~nding machlne~ whlch use belt ~nders is that the rollers on the bcl ~ander ma~t b- car~fu~ ly ~ usted to ensurs th~t ~ Z006366 the plane of the sandlng belt 18 parallel to the flat ; surface on the workpiece. Such a~ustment i8 not only tlme coneuming, but will also result ln lmproperly ganded workpieces unless performed properly.
5 S A stlll furth~r disadvant~go o~ th~so prevlously Q known sanding machines whlch use belt sanders $8 that the sanding belt may deflect or bow during a sanding operation thus machin$ng a bowed surfac~ on the workplece. Th$s ig partlcularly true when the ~andlng machine $e operated at h$gh machining rates.
Summarv of the Present Invention ~ he present lnvention provides a ~andlng m~chlne wh$ch overcomes all of the above mentloned di~adv~ntages o~
~ the pr-viously known devices.
l~ z In brief, the sanding machine of the present lnvention comprlses a frame and a platen rotatably mounted to the frame about a vertlcal ~Xi8. The workpiece 18 detachably mounted to the platen 80 that the surface to be s~nded faces upwardly and lie6 in a horizontal plane.
20 ~ A motor 18 also mounted to the frame so that lt~
output shaft 18 vertically allgned. A ~andlng dlsc ~8 attached to the motor ~h~ft 80 tha~ the sand$ng dl~c lies ln a horlzont~l plane and ~ B aligned with the flat ~urface on ~ the workpiece. Upon act$vatlon, the motor rotatably drives ~ the abrasive sanding disc $n a first rotatlonal direction.
A second motor rotatably drives the platen with it~
attached workp$ece about its vertlcal axis but ln the oppo~lte rotat~onal direction than the first motor. ~7ith both motor3 actlvated., a etepping motor w$th ball screw : ~ Z006366 drlve vertlcally moves the sanding dLsc agsinst tbe workp~ece surface thus performing the sandlng operstion.
A lubricant, such a6 wster, i~ ~upplle~ to the ~ center of the ~andlng disc during the sandlnq oper~tlon in ~ order to prevent overhesting of the workplece. Prefernbly~
the output shaf~ for the sanding dl~c motor 1B hollow ond orms a fluid conduit for the lubric~nt.
A prlmary adv~ntage of the present inventlon 1~
~ thst inexpensive ~andlng discs sre u~ed to ~and the 0 workpiece surf~ce. Furthermore, these dl~cs sre 8upportéd again~t bowing by a rigid ssnding ~iBC mounting plate ~o thst a perfectly flat surf~ce 18 obtsined on the workpiece.
Brie Desccl~tlon of the Drawlnc ~ A better understanding of the present lnventlon z will be had upon reference to the followlng detslled de~cription, when read in con~unction with the sccompanying drswing, wherein llke reference char~cters refer to like partB throughout the several vlews, and ~n whlchs FIG. 1 is a side vlew lllustrat~nq a peeferred ~ embodlment of the pr~ent lnventlon;
FIG. 2 in a top diagrsmmatlc v$ew illustrstlng the prefeered embodiment of the pre~ent lnventions and ~ FIG. 3 $8 a psrtlsl fragmentary view ~llustratlng a ; ~ portlon of the prefeeeed embodiment of the present ~ lnvention.

- ~ Deta~led De~cripSlon oi' the Preferrçd Embodiment of the Present Invention ¦ With reference fir~t to FIG. 1, ~ peeferred - ¦ embodiment of the ~anding machine 10 of the present .,,.
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invention is there~hown and comprises a ~rame ~2. The frame 12 include~ a vertlcally extend~ng set of ways 14.
A motor 16 has a houslng 18 attached to a sllde ~ table 20 wh$ch ~n turn is ver~ically slidably mounted to the ~ ways 14. A stepping motor 22 with ball screw drive 23 is mechanlcally coupled to the 611de table 20 so that rotation of the ball screw dr$ve 23 move~ the motor 16 vertlcally between its retracted position, ~llustrated in ~olid line, and a machin$ng po~ition, illustrated in phantom line. In the well known fa~hion, rotat~on of the ball screw drlve 23 in one direction moveæ the motor 16 upwardly wh~le rotat10n ln the oppos$te d$rect$on moves the motor 16 downwardly.
Counterweights 23 are attached to the sllde table 20 and ~ thus to the motor housing 18 by a cha~n 25 and ~sist the z 8tepp$ng motor 22 w~th ball screw drive 23 $n moving th-motor 16 between lts machining posit$on and its retracted position.
Other means, such as a hydraulic or pneumatic actuator can be used to move the motor hous~ng 18 along the ¦ ways 14.
~ he motor 16 has an output ~hsft 24 rotatable around a vertical axi~ 27 wlth a sanding disc mounting plate 26 attached to lts lower end. The motor 16 is preferably ~n ~ electric motor and, when activated, dL~ves the shaft $n a : 25 ~ f$rst rotation~l direction as ind~cated by arrow 28 ~FIG.
2), A circular abrasive sanding disc 30 i5 attached to ¦ a ~upport 32 in any conventiondl fashion, such ~8 by an ¦ adheslve. The support 32 is con~tructed o~ a rigid material ~ . Z006366 such as steel ~nd i8 detachably secured to the mounting pl~te 26 by bolt3 34 ~only one shown). Furthermore, ~ be~t shown in FIG. l, the support 32 and mountlng plate 26 are ~ arranged so that, with the ~upport 32 and mQuntlng pl~te 26 ~ secured together, the sanding disc 30 18 maint~lned in a n horizontal plane, l.e. a plane perpendicular to the ~XiB 27 o the motor ~haft 24.
Still referring to FIG. l, the motor ~haft 24 i~
preferably tubular thus having ~ centr~l throughbore 36.
The lower end of the throughbore 36 reglsters wlth hole~
formed in the mounting plste 26, the ~upport 32 and the sanding dl~c 30. The other or upper end of the motor shat 24 i8 connected through a rotacy fluid coupllng 42 and ~ condult 44 to a source 46 of lubricant, such a~ water.
z Con8eguently, in operat~on, lubrlcant i~ provided to the centee of the sanding dl~c 30 from the lubelcant source 46.
Wlth reference now to FIGS. 1-3, a circular worktable 4B ls rotat~bly mounted to the fr~me 12 by an axle ~ 50 ~o that the worktable 48 rotates around a vertical axi~
~ 52 bene~th the Qanding disc motor 16 and lts assoclated sanding dl~c 30. An indexing motor 54 ~FIG. l) rotatably ~ drives the worktable 48 in ~ fa~hion to be sub~equently - ~ descrlbed.
~ At least one, and prefer~bly several, platens 56 ~ are ~,ounted to the worktable 48 80 that the platens 56 are ead$ally eguidistsntly spaced ~com the worktable axls 52 and ~ are circumferentlally eguidistantly ~paced from each other.
: The pl~ten~ 56 are ~ubstantlally identlcal to each other so th~t only one platen 56 will be descrlbed in detail, lt . Z006366 belng understood that a l$ke descrlptlon wll~ apply to the other platen~ 56.
With re~erence then to FIG. 3, a palr o~ bearing assemblies 58 rotatably mount the platen 56 to the worktable 5 a 48 so that the platen 56 eot~tes ~bout a ve~tical axls 57 and thus an axis parallel to the axis 27 of the motor shaft 24. A hydraulic motor 60 rotatably drlves an output gear 62 which meshes w$th a geae ring 64 secured around the platen ~ 56. Upon ~ctlvation o~ the motor 60~ the motor 60 rotatably lO 0 drlves the platen 56 ln the opposlte rotatlon~l dlrectlon indicsted by arrow 61 in ~IG. 2 th~n the direction of rotation 28 (FIG. 2) of the sanding disc 30 for a re~son to be 6ub~equently descrlbed.
~ The workpiece 66 (FIG. l) ~8 secured to the platen 15 z 56 80 that surface 68 to be sanded faces upwardly ana l~eJ
ln a generally horlzontal plane. Any conventional mean~
such as cl~mps 70 can be u~ed to attach the workpiece 66 to the platen 56.
~ With reference now to FIG. 1, the operation of the 20 ¦ p~esent invention will now be described. After the workplece 66 18 secured to the platen 56, the lndexing motor 54 rotate6 the worktable 48 until one platen 56 18 positioned at a work~tation 72 allgned with the sanding di~c ~ 30. ~he lndexlng motor 54 is then ~topped. Furthermore, ~s 25 ~ best ~hown in FIG. 2, although the axes 27 ~nd 57 of the e sanding dlsc 30 and plat~n 56 ~re parallel to each other, ~ the6e axea 27 and 57 are radially spaced fcom e~ch for 30 i reaDOn t~ ~ub~equently dercrlbed, ! -6-,, ' The ~anding dlsc motor 16 ~nd platen motor 60 ~re then activated 80 that the s~nd$ng dl~c 30 and workp~ece 66 are rotatably driven ln opposite rotat~onal d~rect~ons. ~he ~ stepping motor 22 and ball screw drive 23 then move~ the ~ sanding disc motor 16 from its retracted to it~ operating _ position 80 that the sanaing dlsc 30 contacts the workpiece ~urface 68 and performs the sandlnq operation.
Slmultaneously, lubricant i8 ~upplied from the source 46 to ~ the cen~er o~ the s~nd~ng d~ 8C 30 to prevent overhe~tlng of ~ both the workpiece ~nd the sanding disc 30.
Ai previously descrlbed, the oxes 27 and 57 of the sand~ng disc 30 Dnd platen 56 are radially offset from e~ch i other. Thi6 prevents the occurrence of an unsanded spot at the center of the workplece surface 68 which would occur lf z the axes 27 and 57 were coaxial.
Aftee completion of the ~andlng operatlon, the tepp~ng motor 22 and ball ~crew dr$ve 23 move~ the motor 16 to its retracted positlon. ~he lndexinq motor S4 then moves ~ the next platen 56 to the work ~tation 72 and the above ~ described process 1~ repeated.
- ~ Although the axes 27, 57 and 52 have all been descrlbed as veetical, it will be understood th~t these axes may be otiented ln non-vertical directlons. However, the ~ axe~ 57 and 27 must be parallel to each other.
25 g From the ~oregoing, lt can be seen that the present invention achleves many advantages over the previo~sly known devices. One such adv~ntage is that inexpenslve sandlng discs can be used instead o~ more expensive ~andlng belts;
,' , .

A still further adv~ntage of the pre~ent lnventlon ~3 that the sand~ng dlsc i8 held ln a flat cond$t$on by lt8 rigid suppo~t. Thus, all bowlng of the sandlng Clsc $8 ~ completely avolded.
~ Yet another advantage of the pre~ent lnventlon i8 that the lubricant system $s inexpenslve and yet tot~lly f effective in operatlon.
~ aving described my lnvention, m~ny modiflcat$ons ~ thereto will become apparent to those ~kllled in the art to ~ whlch it pertains without ~evlatlon ~rom the spir$t of the ..
~nventlon as deflned by the scope of the appended clalms.
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Claims

1. A machine for sanding a flat surface on workpiece comprising:
a frame, a worktable mounted to said frame, said worktable having at least one platen, means for attaching the workpiece to said platen so that the flat surface faces away from said platen, a sanding disc, a motor for rotatably driving said disc around a first axis and in a first rotational direction, said first axis being perpendicular to the flat surface, and means for mounting said motor to said frame so that said disc contacts said flat surface.

2. The invention as defined in claim 1 and comprising means for rotatably driving said platen about a second axis parallel to said first axis and in a second rotational direction opposite from said first rotational direction.

3. The invention as defined in claim 2 wherein said first and second axes are radially spaced from each other.

4. The invention as defined in claim 1 and comprising:
a source of liquid lubricant, and means for supplying said lubricant to a central point on said sanding disc.

5. The invention as defined in claim 4 wherein said central point on said sanding disc coincides with said first axis.

6. The invention as defined in claim 5 wherein said lubricant is water.

7. The invention as defined in claim. 4 wherein said motor comprises a tubular drive shaft, said tubular drive shaft forming a conduit for said lubricant.

8. The invention as defined in claim l wherein said mounting means comprises a slide assembly, said slide assembly having a set of ways and a slide table positioned over said ways, said ways being secured to said frame so that said slide is parallel to said first axis, said slide table being secured to said motor, and means for moving said slide along said ways so that said sanding disc contacts said flat surface.

9. The invention as defined in claim 8 wherein said moving means comprises a stepping motor and ball screw drive.

10. The invention as defined in claim 2 and comprising means for rotatably mounting said worktable about a worktable axis to said frame, said worktable axis being parallel to and radially spaced from said second axis, a plurality of platens, each platen being rotatably mounted to said worktable so that the axes of the platens are parallel to each other and equidistantly spaced from the worktable axis, and means for indexing said worktable to sequentially move the axes of the platens into alignment with said second axis.

11. The invention as defined in claim 1 and comprising means for removably securing said sanding disc to said motor.