US2492231A - Portable sander - Google Patents

Description

S. MANDL EIAL PORTABLE SANDER Dec. 27, 1949 s sheets-sheet 2 Filed June 18, .1945

www m INVENTORS PORTABLE SANDER 3 Sheets-Sheet 3 Filed June 18, 1945 E'.6. fg y /al 70 INVENTORS BYI77W Patented Dec. 27, 1949 PORTABLE SANDER Siegmund Mandl,

Hauser, Elm Grove,

of Wisconsin immuun June 1s, 194s, serai mi. coaozo- A 12 claimt. (01.51L-ii fine Ypige.sent;invention. ates in general to improvements in the art of dressing surfaces by abrasion, and relates more especially to improvements in the construction and operation of reciprocatory sanding, polishing, or analogous devices for smoothing surfaces of diverse objects by rubbing or abrasive action.

The primary object of our invention is to provide an improved portable sander Aor the like having a working surface reciprocable from a rotary source of power, and which is simple and compact in construction, emcient in operation, and exible in its adaptations.

A It is frequently desirable in many industries, to have available arelatively light and compact portable sanding unit operable from a relatively stationary source of ,rotary motion such as an electric or fluid pressure operated motor, and wherein the working surface is rapidly reciprocable so as to produce smoothly dressed surfaces upon the work. While various types of such portable sanders have heretofore been proposed and used commercially, none of these prior devices are entirely satisfactory either because they are not suillciently compact for convenient manipulation in cramped localities such as corners, or because they were too complicated and unreliable in operation, or because they produced excessive vibration and jarring which was very annoying to the operato or because the parts of the mechanisms were not well protected from dust and grit and could not be readily inspected or renewed. For these reasons, most of the prior portable reciprocatory sanding aemblages have not become popular with the trade, and the use of these units has been rather restricted and limited.

It is therefore a more specic object of the present invention to provide a new and useful portable reciprocatory sander unit especially adapted to be operated from a xed source of rotary power,` and which definitely overcomes all of the above mentioned objectionable features of prior apparatus of this type.

Another specific object of this invention is to provide an improved reciprocable smoothing or polishing assemblage operable by rotary power most effectively applied to the working shoe or element of the device, and wherein the various parts are normally well concealed and protected,

' while still being readily accessible for inspection and renewal.

A further specic object of our invention is to provide a durable, compact, and manually controllable sander, which is readily manipulable in Milwaukee, and Edward M.

Wis., assignors to Blackhawk Mfg. Co., Milwaukee, Wis., a corporation any desired direction and in corners and other limited spaces, and which moreover will not subthev following detailed description, and some of the novel features of motion transmitting and converting mechanisms, disclosed but not specifically claimed herein form the subject of other co-pending applications.

A clear conception of the several features con- -stituting the present improvement. and of the mode of constructing and of manipulating a portable sanding unit embodying our invention,

may be had by referring to the drawings accompanying and forming a part of this specification wherein like reference characters designate the same or similar parts in the various views.

Fig. 1 is a part sectional side elevation of one of the improved portable sanding units showing the working shoe in foremost position, most of the section having been taken centrally and longitudinally through the unit, but a portion thereof having been taken forwardly of the central plane, as indicated by the line l-I of Fig. 4;

Fig. 2 is a view similar to that of Fig. 1 with a portion of the manipulating handle broken away, and showing the working shoe in rearmost position or end of its reciprocatory motion;

Fig. 3 is a fragmentary transverse section through one of the sand paper clamping or attaching devices of the sanding unit, taken along the line 3-3-of Fig. 2;

Fig. 4 is a transverse. longitudinal section through the portable sanding assemblage, taken along the line 4-4 of Fig. 1;

Fig. 5 is another transverse longitudinal section through the sanding outfit taken along the line 5-5 of Fig. 1;

Fig. 6 is still another transverse longitudinal section through the portable sander, taken along t the line 6-6 of Fig. 1;

Fig. 7 i's a part sectional rear end view of the sanding mechanism, the section having been taken along the line 1-1 of Fig. 1, but showing the rear sander shoe clamp in active position and the front clamping lever released;

Fig. 8 is an enlarged side elevation of one of asoassr 3 the improved sander shoe clamping levers removed from the shoe;

Fig. 9 is a fragmentary view showing a modified anti-friction tapered roller; and

Fig. 10 is a fragmentary view showing an antifriction ball bearing between the body and base, and the reciprocable plate.

Although our invention has been shown and described herein as being embodied in a portable sanding unit having a reciprocable sand paper carrying shoe operable by a rotary motion con verter carried by the unit and which is in turn operable from a relatively xed source of rotation, it is not our desire or intent to unnecessarily restrict or limit the utility of the improved features by virtue of this specific embodiment, since some of these features may be more generally applicable to sanding devices driven by various types of rotary motors disposed either remotely from or mounted directly upon the unit.

Referring to the drawings, the improved portable sander shown therein by way of illustration, comprises in general a durable and sturdy elongated frame or body I having therein a longitudinal central bore I I closed at one end by a wall I2 and having its opposite end provided with internal screw threads I3; a manipulating handle I4 coacting with the upper or top side of the body I0; a shoe supporting and guiding base I5 coacting with the lower or bottom side of the body I0 through a gasket I6, and being firmly but removably attached to the body Il together with the handle I4 by means of four screws I1; a sand paper carrying shoe I8 reciprocably suspended fromthe outer lower face of the base I5 and normally having an abrasive sheet I9 applied thereto; a flexible rotary power shaft 2Il for delivering power to the unit through the open end of the body bore II through a rotarydriving member 2|; and mechanism including a rotary driven member 22, a reciprocable plate 23, and a motion converting element 24 and roller 25, all confined within the bore II and base I5 for converting the continuous rotary motion of the shaft 20 into reciprocating movement and for constantly imparting the latter to the shoe I8.

The main frame or casing I0 has fiat parallel top and bottom faces against which the handle I4 and base I5 are normally firmly attached by the screws I1, and may be provided with external ribbing as shown in Figs. 1, 2 and 7; and the inner end of the bore II is of reduced diameter, while the outer threaded end of this bore is normally closed by a hollow removable plug 26 within which a bearing sleeve 21 for the rotary driving member 2 I 'may be slidably and detachably confined by means of two manually releasable latches 28, 29 which are pivotally suspended from the plug 26 and are engageable with annular grooves 30, 3I

' member 2| is concealed within a exible tubular non-rotary casing 32 secured to a fitting 33 which is screw threaded into an end socket of the normally non-rotating bearing sleeve-21, but the shaft 2l may normally be constantly rotated by means of an electric or fluid pressure actuated motor, or from ans1 other suitable flxed source of power associated with the power receiving end of this shaft 20. The Opposite inner end of the driving member 2l is provided with a polygonal driving projection 34 secured thereto by a shear pin 35, and the driven member 22 which is rotatable within the bore II of the body I0 is provided with a rigid central tube 33 the projecting outer end of which has a cross-shaped socket 31 therein cooperable with the driving member projection 34 to provide a direct rotary motion transmitting connection between the members 2I, 22.

The rotary driven member 22 is mounted for free'rotation within the body bore II by and between spaced anti-friction end thrust resisting bearings 38, 39 one of which is located near the reduced inner end of the bore II and coacts with an integral central projection 40 of the member 22, and the other of which coacts with the tube 36 near the socket 31; and the enlarged intermediate portion of the member 22 is thus prevented from shifting axially, and is provided with a tapered annular peripheral groove 4I disposed in a plane which is inclined relative to the common central axis of the members 2I, 22. The bearings 38, 39 are normally clamped in position by means of a removable threaded bushing 42 coacting with the internal screw threads I3 of the body III, and the plug 26 is likewise norm'ally held in place by this bushing 42 and another removable bushing 43 also coacting with the screw threads, and between which a ange 44 formed integral with the plug is conned. The bushings 42, 43 are provided with end notches adapted for application of a Spanner wrench. and may thus be inserted or removed to permit convenient insertion and removal of the plu'g 29, bearings 33, 39, and driven member 22 relative to the bore II. A packing 45 is preferably disposed within the inner,

bushing 4 2 and between the bearing 39 and the inner ends of the plug A28 and bearing sleeve 21 so that the bearings 33, 39 and the rotary driven member 22 may be conned in suitable lubricant, and a plunger pin 46 slidably confined within the tubev 3S is constantly urged by a compression spring 41 toward the socket 31thereby tending to push the driving projection 34 out of the socket and to thus interrupt the driving connection between the members 2I, 22 at all times.

The latches 28, 29 which are formed for coaction with the grooves 30, 3I of the bearing sleeve 21, are pivotally supported upon the plug 28 and are spring pressed toward the sleeve 21 so that when either latch is brought'into alineV ment with an adjacent annular groove lt will snap into the groove. 'I'he latches 23, 29 are however independently or simultaneously manually releasable by the operator to either merely release the sleeve 21 for automatic interruption of the driving connection between projection 34 and the socket 31 by the spring 41 and plunger 46, or to effect complete removal of the sanding unit from the bearing sleeve 21. If only the latch 28 is released, the spring 41 and plunger 46 wil1.push the projection 34 out of the socket 31, and will also shift the bearing sleeve 21 outwardly until the latch 29 snaps into the annular groove 3|, thus preventing this sleeve from becoming detached from the plug 25, and permitting the driving connection between the projection and socket to be quickly re-establlshed by merely pushing the sleeve 21 back into the position shown. However, if both latches 23, 29 are released, the sleeve 21 together with the driven member 2l and its driving projection 34 may be freely axially withdrawn from the plug 26, and it is noteworthy' that the sanding unit may at all times be freely rotated about the longi-` tudinal axis of the bearing sleeve 21 due to the annularity of the grooves 39, 3I with which the latches coact.

The reciprocable motion transmitting plate 23 driving plug and oil seal retainer amasar is slidably confined within the base I8 and is provided with an integral central boss 48 having a bore with which the" motion converting element 24 coacts, and with four smaller integral bosses 48 to each of which a combined shoe 88 is iirmly attached by means of a cap screw 8|, see Figs. 1, 2, 4, 5 and '1. The motion converting element 24 is freely rotatable within the bore of the boss 48, and has an enlarged medial flange 82 coacting with the top of the plate 23 and movable along a slot 83 formed in the body I8, while its upper portion is provided with an integral cylindrical projection 84 upon which the tapered roller 28 is freely rotatable. The roller 25 constantly engages the tapered inclined groove 4I of the rotary driven member 22, and coacts with a bearing plate 88 embracing the projection 54 and engaging the flange 82. In order to reduce friction losses to a minimum, an anti-friction or ball bearing 25 may be substituted for the plate 88 and interposed between the tapered roller 25 and its supporting projection 84 as shown in Fig. 9; and anti-friction bearing balls 88 may also be provided between the upper end heads of the four screws 8l and special sockets '5I' secured to the body I8 as illustrated in Fig. 10.

The base I5 which is firmly secured tothe body I8 by the screws Hand is sealed at its top by the gasket I8, is also provided with a guiding recess within' which the plate 23 is reciprocable and with four through openings 81 into which the bosses 48 of the plate 23 project, l

vand a flexible cup-shaped seal 88, preferably formed of soft rubber, is interposed between each opening 81 and the adjacent boss 48 as clearly shown in Figs. 1, 2, 4, 5 and fl.. These cupshaped seals 88 have their peripheral rims firmly secured within the xed base openings 81, while their inner tubular portions are likewise firmly secured to the bosses 48 by the retainers 88 .and cap screws 5I associated with the reciprocable plate 23, thus providing a positive seal for the body bore II and for the interior of the base I8 while permitting free reciprocation of the plate 23 relative to the body and base. Each driving plug or retainer 88 may also be provided with a medial stop flange cess 88 adjoining the flange 88 for facilitating attachment of the sanding assemblage thereto.`

The improved sanding assemblage comprises the shoe I8 consisting of a re-enforced metal sled 8l, a bre base board 82 coacting with the sled 8l, and a felt pad 83 board 82 as depicted in Figs. 1, 2, 3, 6 and '1. The sled 8| is provided with four sockets 84 which are adapted for snug reception of the lower ends of the retainers 88, and a pair of latch levers 88 are swingably supported upon the sled 8| by means of pivots 88 and are provided with resilient peripheral wedge wings 81 adapted to engage the recesses 88 of the adjacent retainers 88 as clearly shown in Figs. 6, A'l and 8. The

88 and with an annular re-l I 6 f with adjusting slots 13, and these eccentric portions 12 snugly engage the sled bearings 'I8 while the cylindrical intervening portions of the tubes 1I are adapted to firmly clamp the opposite ends of a sheet of sand paper I8l or the like, against the rounded ends of the sled 8| and in stretched condition across the pad 83, when the tubes 1I are properly rotated with the aid of a screw driver or similar implement. The sled 8i may also be provided with depending side walls as shown in Fig. 7 for the purpose of retaining the board 82 and pad 83 in proper position beneath the sand paper I8.

During normal use of the improved sanding unit, the improved sanding shoe assemblage I8 should be applied to the retainers 88 and locked thereto with the aid of the latch levers 88 by causing the wings 81 of these levers to coact with the recesses 88 of the four retainers, as shown at the right of Fig. 6 and in Fig. '1. A sheet of sand paper I8 or the like. should then be stretched taut across the felt pad 83 and the opposite ends of the sheet I8 should then be inserted between the clamping tubes 1I and the upper end portions of the sled 8l. By subsequently rotating the tubes 1I with the aid of a screw driver or the like applied to the slots 13 of the eccentrics 12, the ends of the sand paper I8 may be firmly lclamped to the sled while at the same time further stretching the sheet into snug engagement with the soft pad 83, thereby providing an eiective sanding or working surface. The chambers within which the plate 23, element 24, roller 28,' and driven member 22 are confined should be provided with proper lubricant which will be sealed within these chambers by the gasket I8, packing 48, and seals 88, whereupon power may be applied from any suitable source to constantly rotate the flexible drive shaft 28 and the driving member 2I.

In order to thereafter operate the sander, it is yonly necessary to force the bearing sleeve 21 inwardly so as to cause the driving projection 34 to enter the socket 31 of the driven member 22 and to also cause the outermost latch v28 to. en'- gage the outer recess 3 8 of the sleeve 21. Rotary motion will then be transmitted directly from the rotary driving member` 2l rto the rotary driven member 22 confined within the body bore II, and as the member 22 rotates, the inclined peripheral groove 4I willcoact with the roller 28 to cause the element 24 upon which the roller is supported, to reciprocate the plate 23 within its coacting with the levers 85 are adapted to coact with special Vfricconfines in the base I8. This, reciprocation of the plate 23 isl transmitted through the bosses 48, seals 51,cap screws 8l, and retainers 58 to the sled 8| of the shoe assembly I8, thus causing the sandpaper I8 which is carried by the shoe I8 to likewise reciprocate. The abrasive face of the sandpaper I8 may then be applied to the work by manipulating the unit with the aid of the handle I4; Yand the annular recess 38 with which the latch 28 coacts will permit the unit to be rotated about the bearing sleeve 21, while the ilexible drive shaft 28 and casing 32 will also permit the unit to be moved about freely in any direction. The rotary motion of the drive shaft 28 and member 2l are thus effectively converted into reciprocatory movement of the sanding shoe, and the fexible cup-shaped seals 88 thoroughly protect the motion converting parts of the mechanism against dust and grit without interfering or obstructing the motion transfer.

In order to stop the reciprocation of the shoe assemblage I8, it is only necessary to release the 78 latch 28 whereupon the compression spring 41 a-teaaai and plunger 46 will immediately become eiective to force the driving projection 34 out of the socket 31, thus interrupting the driving connection. 'I'he latch 28 will then snap into the inner recess 3l of the sleeve 21, thereby preventing this sleeve from being forced out of the closure plug 26. but if it becomes desirable to remove the sanding unit from the bearing sleeve 21, both latches 28, 28 may be released whereupon the sleeve 2l may be freely withdrawn from within the plug 26. When the sleeve 21 is thus removed from the sanding' unit, the packing 45 will still maintain a seal for preventing escape of lubricant, and if it becomes desirable to remove the plug 26 and other internal parts of the unit, it is only necessary to remove the bushings 43, 42 with the aid of a spanner wrench. The sanding shoe assembly I8 may obviously be removed from the motion transmitting mechanism of the unit by merely releasing the lever 65 as shown at the left of Fig. 6, whereupon the sled 6I may be freely withdrawn from the retainers 50. It is also to be noted that the levers 65 are irictionally held in latching position by the holding screws 68 of the sled 6l, thus preventing possible accidental release of the sled from the power transmitting mechanism during normal use of the improved assemblage.

From the foregoing detailed description it will be apparent that our present invention provides an improved portable sanding unit which besides being extremely simple, compact and eiiicient, is readily manipulable in any desired position and in corners and other cramped localities. All of the internal movable parts and bearings of the improved unit, are thoroughly concealed and protectedlagainst possible entry of dust and grit, while still being readily accessible for inspection with the aid of ordinary tools. The improved reciprocating sander shoe assembly I8 may be quickly and conveniently applied to or removed from the motion transmitting mechanism, and the abrasive sheet or sandpaper I9 may be quickly and conveniently replaced without removing the shoe assembly from the unit. The tubes 1I with their eccentrics I2 provide simple and compact means for stretching the sandpaper I9 against the resilient pad 63, and this pad 63 provides a cushion for the working stretch of the sandpaper IS. The improved sanding unit may be operated at high or low speeds, and has actually been successfully operated at driving shaft speeds of three thousand revolutions per minute, and the latches 28, 2! cooperating with the spring 41 and plugs 21, provide simple means for applying and for interrupting the power, while also permitting convenient removal of the sandingmunit Afrom its driving source. Any suitable type ot rotary motor may be utilized for propelling the unit, and the motor may either be disposed remotely from the unit or applied directly to the driving member 81 thereof. The invention hasin fact proven highly satisfactory and successful in actual use. and is operable without. subjecting the operator to undesirable and annoying vibrations, while also being adapted to be manufactured and sold at moderate cost for diverse uses.

The specific formation of the motion transmitting plate 23 and of the seals 58 cooperating therewith, are important features of the present improvement, since these parts cooperate to effectively guide and reciprocate the shoe assemblage I8 while positively preventing i'oreign'matter such as grit or dust from reaching the motion converting elements. The plate 28 is snugly but slidably confined within the guiding recess formed in the upper portion of the base I5 and has the motion converting element 24 pivotally mounted upon its central portion, and the four flexible cup-shaped seals 58 coact withthe depending plate bosses 49 and with the openings 51 in the base I5 to constantly conceal the plate 23 within the base recess while still permitting free and, unrestrained reciprocation of the plate 23. Since the four bosses 49 are located remote from the central driving element 24 and coact with the shoe assemblage I8 near the four corners thereof, this assemblage is eiectively conned to reciprocating movement during normal operation. and the location and formation of the four corner seal retainers 50 makes it possible to efiect attachment and removal oi the sled 6I with the aid of only two latch levers 85.

It should be understood that it is not desired to limit this invention to the exact details of construction or to the precise mode of use, herein `shown and described, for various modications within the scope of the appended claims may occur to persons skilled in the art; and it is contemplated that specific terms such as Sanden base, plate, shoe, body, and the like, be

given the broadest possible interpretation consistent with the prior art.

We claim:

1. A portable sander comprising, a body having a recessed base, an elongated plate slidably confined within the recess of said base and having two pairs of laterally spaced rigid protrusions extending through parallel openings in the base, means within said body for reciprocating said plate, a-sander shoe reciprocable by said plate externally of said base, and a flexible seal interposed between each of'said plate protrusions and the adjacent base opening.

2. A portable sander comprising, a body having a recessed base, an elongated plate slidably coniined within the recess of said base and having two pairs of laterally spaced rigid protrusions extending through parallel corner openings in the base, means within said body for reciprocating said plate, a sander shoe reciprocable by said plate externally of said base, a single latch lever for detachably connecting each pair of said plate protrusions to said shoe, and a exible cupshaped seal interposed between each of said protrusions and the adjacent body opening.

3. A portable sandercomprising, a body having a base, an approximately rectangular plate slidably coniined within said base, means within said body for reciprocating said plate, a ilexible seal interposed between said base and said plate 'near each of the four corners of said plate, an approximately rectangular sander shoe reciprocable externally of said base, a retainer for each of said seals reciprocable by said plate, and-means for detachably attaching said shoe to all of said retainers.

4. A portable sander comprising, a body having a base, an approximately rectangular plate slidably confined within said base, means within said body for reciprocating said plate, a flexible seal interposed between said base and said-plate near each of the four corners of said plate, an approximately rectangular sander shoe reciprocable externally of said base, a retainer for each of said sealsv reciprocable by said plate, and a pair of latch levers carried by said shoe and coacting with said retainers to attach said shoe to said plate, each of said levers cooperating with several of said retainers.

9 5. A portable sander comprising, a body having a base, an elongated plate slidably confined within said base, means within said body for reciprocating said plate, a ilexible cup-shaped seal interposed between said base and said plate neai` each of the four corners of said plate, an elongated sander shoe reciprocable externally of said base,

- interposed between said base and said plate near each of the four corners of said plate, an elongated sander shoe reciprocable externally of said base, a retainer for each of said seals reciprocable by said plate, a driving connection between said plate and shoe piercing each of said seals, and a pair of latch levers carried by said shoe and coacting with said retainers to attach said shoe to said plate, each of said levers cooperating with several of said retainers.

7. A portable sander comprising, a base having corner openings, an elongated plate slidable on one side of said base, means for reciprocating said plate, a flexible seal confined within each of said,corner openings, an elongated sander lslice reciprocable along the other side of said base, a driving connection interposed between said plate and shoe at each corner of said base and piercing the adjacent seal, retainers for said seals, and means for detachably attaching said shoe to all of said retainers.

8. A portable sander comprising, a base having corner openings, a plate reciprocable along one side of said base, means carried by said base for reciprocating said plate, a sander shoe reciprocable along the other side of said plate, parallel driving elements projecting laterally from the corners of said plate through said base openings and drivingly engaging the corresponding corners of said shoe, a cup-shaped seal interposed between each of said connections and the adjacent base opening, and means for detachably attaching said shoe to all of said connections.

9. A portable sander comprising, a body Vhaving an approximately rectangularbase provided with corner openings, a cup-shaped seal confined within each of said openings. each of said seals having an outer tubular Wall snugly fitting the adjacent base opening and an inner tubular wall connected to its outer wall by a exible diaphragm, a plate slidably conned within said base, means within said body for reciprocating said plate, a sandershoe reciprocable externally of said base, and a driving connection between said plate and said shoe piercing each of said seals and snugly engaging the inner wall of the adjacent seal.

10. A portable sander comprising, a body havlng an approximately rectangular base provided 55 Number with corner openings, a cup-shaped seal confined within each of said openings, each of said seals having an outer tubular wall snugly tting the adjacent base opening and an inner tubular 5 wall connected to its outer wall by a flexible diaphragm, a plate slidably confined within said base, means within said body for reciprocating said plate, a sander shoe reciprocable externally of said base, a driving connection between said i0 plate and said shoe piercing each of said seals and snugly engaging the inner wall of the adjacent seal, and means for detachably attaching said shoe to said driving connections Afrom the exterior of said body.

11. A portable sander comprising, a hollow body having a polygonal base provided with corner openings, a cup-shaped seal confined Within each of said openings, each of said seals having an outer tubular wall snugly tting the adjacent base opening and a coaxial inner tubular wall integrally united with its outer wall by a flexible bottom, a plate reciprocable in said body at one side of said base, means for reciprocating said plate, a sander shoe reciprocable externally ol said ,body at the other side 0i' said base, and a driving element connecting said plate and said snoe thro ugh each of said openings and snugly engaging the inner tubular wall of the adjacent seal.

.a 12. A portable sander comprising. a hollow body having a polygonal base provided with corner openings, a cup-shaped seal conned within each oisaid openings, each of said seals having an outer tubular wall snugly tting the l vadjacent base opening and a coaxial inner tubular wall integrally united with its outer Wall by a exible bottom, a plate reciprocable in said body at one side of said base, means for reciprocating said plate, a sander shoe reciprocable externally of said body at the other side of said base, a driving element connecting said plate and said shoe through each of said openings and snugly engaging the inner tubular wall of the adjacent seal, and means for detachably attaching said 5 shoe to said driving elements from the exterior of said body.

SIEGMUND MANDL. EDWARD M. PFAUSER.

so REFERENCES CITED The following references'are of record inthe le of this patent:

UNITED STATES PATENTS Name Date 1,761,059 Norman et al.v June 3, 1930 1,818,361 Schwabe Aug. 11, 1931 2,123,426 Kohle July 12, 1938 2,193,419 George Mar. 12, 1940 2,204,486 George June 11, 1940 2,395,537 Crosby Feb. 26, 1946 FOREIGN PATENTS Number Country Date 05 614,838 France Nav. 29. icao

Images