US3123386A - Sander - Google Patents

Description

March 3, 1964 v. L. FRANTZ 3,123,386

SANDER Filed Dec. 29, 19e1 2 Sheets-Sheet l FIG. 3

J In v e n to r Virgil L. Frantz his Attorney March 3, 1964 Filed Dec. 29, 1961 Q I C) I8 I 20 k -2/ H 25 I- H i 4 a 24 5 I I 36 H 23 6a i 24 I I 25 LLE 2/ FIG. 4

FIG. 5

v. L. FRANTZ 3,123,386

SANDER 2 Sheets-Sheet 2 FIG. 7

FIG. 8

Virgil L. Frantz YWMM his Attorney United States Patent 3,123,386 SANDER Virgil L. Frantz, Salem, Va., assignor to Graham-White Sales Corporation, Salem, Va., a corporation of Virginia Filed Dec. 29, 1961, Ser. No. 163,312 21 Claims. (Cl. 2.9111) This invention relates to sanders for locomotive and like sanding systems and has for its primary object the provision of an improved sander whereby the quantity of sand applied during a sanding operation of a given duration is adjustable over a wide range and to suit sands of difi'erent characteristics.

Another object of the invention is to provide an improved sander by which the rate of discharge of sand during a sanding operation is regulatable independently of the pressure of the actuating air.

An additional object of the invention is to provide an improved sander wherein the actuating air is admixed without turbulence with the sand, thereby eliminating any cutting action by the sand whether the admixing is within or beyond the sander.

A further object of the invention is to provide a sander wherein the sand flows by gravity at a regulated rate from a sand chamber to the point of admixture with actuating air and is discharged from the chamber without being subjected therein either to turbulence or to suction by the air, thereby enabling the rate of discharge of the sand to be regulated with a preciseness heretofore unobtainable.

Another object of the invention is to provide an improved sander of such arrangement and construction that its clean-out port can be opened and closed without interference by sand in the body thereabove.

A further object of the invention is to provide in a sander a clean-out plug which is readily applied and removed without use of tools, is practically foolproof and is eifective to seal the clean-out port against leakage.

Other objects and advantages of the invention will appear hereinafter in the detailed description, be particularly pointed out in the appended claims and be illustrated in the accompanying drawings in which:

FIGURE 1 is a side elevational view of a preferred embodiment of the sander of the present invention;

FIGURE 2 is a front elevational View of the sander of FIGURE 1;

FIGURE 3 is a vertical sectional view on an enlarged scale taken along lines 33 of FIGURE 2;

FIGURE 4 is a view of the sander partly in top plan and partly in a horizontal section taken along lines 44 of FIGURE 1;

FIGURE 5 is a bottom plan view of the sander of the preceding figures, showing the locking mechanism for the clean-out plug in looking position;

FIGURE 6 is a fragmentary bottom plan view showing the locking mechanism for the plug in release position;

FIGURE 7 is a horizontal sectional view taken along lines 7-7 of FIGURE 1; and

FIGURE 8 is a horizontal sectional view taken along lines 8-8 of FIGURE 1.

Referring now in detail to the drawings in which like reference characters designate like parts, the improved sander or sand trap of the present invention is similar to those of my copending applications, Serial Nos. 774,235, filed November 17, 1958, now Patent No. 3,020,072, and 43,225, filed July 15, 1960, now Patent No. 3,088,764, in controlling the rate at which the sand is discharged by the actuating air by regulating the rate at which the sand flows to the point of admixture with the air. Too, in this and the copending applications, regulation of the rate of flow of the sand to the point of admixture with the air 3,123,386 Patented Mar. 3, 1964 is exercised by providing in the sander a layer or mound of sand, the upper surface of which slopes toward the outlet end of the sand chamber at the gradient or slope fixed by the angle of repose of the particular sand and, by varying the height of that surface above the floor of the sand chamber, correspondingly varying the quantity of sand available for mixing with the air in any given operating cycle. However, although basically similar to the sanders of the prior applications, the sander of this invention is capable of controlling the discharge of the sand with a preciseness heretofore unobtainable and improves upon the earlier sanders in numerous further respects.

In the preferred embodiment illustrated in the accompanying drawings, the sander of this invention is comprised of a body 1, generally of L-shape, with angularly related inlet and outlet legs 2 and 3, the inlet or upper and outlet or front ends 4 and 5, respectively, of which are flanged or otherwise suitably fitted for connection of the inlet end to an overlying sand dome or reservoir (not shown) and of the outlet end either directly or through an extension indicated at 6 to a discharge pipe (not shown). Contained in the body 1 is a sand chamber 7 having connected, angularly related inlet and outlet legs 8 and 9, the former generally vertically disposed within the correspondingly disposed inlet leg 2 of the body and terminating upwardly in an inlet port or inlet or upper end 10 opening upwardly onto the corresponding end 4 of the inlet leg 2 of the body. In turn, the outlet leg 9 of the sand chamber 7 extends generally in a horizontal direction into the bodys outlet leg 3 and terminates out Wardly in an outlet port or outlet or outer end 11. While the bodys outlet leg 3 may extend beyond the outlet end 11 of the sand chambers outlet leg 9, as by making the extension 6 integral with the body, it ordinarily will be preferred that, as in the illustrated embodiment, the chambers outlet leg project or extend through and be coterminous with the bodys outlet leg. However, Whether it opens within or at the end of the body, the outlet leg 9 of the sand chamber should open onto a smooth, uninterrupted bore 12, such as that of the extension 6.

In a conventional sand trap, sand is fed by gravity into a sand chamber 7 from a sand dome and during a sanding operation an air jet is applied directly on the sand in the chamber to discharge it into the associated discharge pipe. Since variation in the pressure of the ac tuating air has little eifect upon the rate of discharge, the result is that the quantity of sand discharged in a sanding operation depends entirely on the duration of that operation. This conventional action has three main undesirable attributes, one that, with the rate of discharge uncontrollable, it is practically impossible for the operator to gauge the quantity of sand applied, another that it makes no allowance for the difference in flow characteristics between sands of different types, and the third that the abrasive action of the sand blast generated in the interior of the trap drastically curtails its service life. None of these undesirable attributes is possessed by the sander of this invention. Instead, the sand and air are mixed outside the sand chamber and the sand flows out of the chamber of admixture with the air at a regulated rate which in turn controls its rate of discharge through the discharge pipe.

With sand fed by gravity through the inlet port 10 from the overlying sand dome and normally substantially filling the inlet leg 8 of the sand chamber, the rate of flow of the sand through the outlet leg 9 in a sanding operation is regulated by a blade or paddle 13 disposed or contained in the body 1 above the connecting passage 14 between the inlet and outlet legs and swingable, oscillatable, slL'ftable or movable to vary its vertical spacing from or above the underlying portion of the floor 15 of the sand chamber and thus the height of the connecting passage. In its preferred form, the blade 13 has a hub 16 which is integral with and extends between a pair of cylindrical discs 17 received and rotatable in apertures 18 in the opposite side walls 19 of the body 1 and of a diameter radially to contain the blade so as to permit the latter to be applied and removed through either aperture. Each of the discs 1'7 preferably carries in a peripheral groove 2%} an O-ring 21 which serves both to seal its joint with its aperture 18 and, by trictionally resisting relative rotation, hold the blade in the position in which it is set.

For locking the blade 13 against axial shifting, as well as to prevent seepage of sand above it into the outlet leg 9, there is provided a shield or looking plate 22 screwed or otherwise releasably attached to the adjoining or overlying front wall 23 of the inner leg 8 and bent therebelow as necessary to extend downwardly substantially to the center or rotative axis of the discs 17. Of substantially the width of the blade 13, at least over its portion contained between the discs 17, the shield 22 preferably has on either side of that portion ears 24-, which conveniently are sectoral and of substantially the radius of the discs and, by rubbing against the latter, aid or augment the frictional action of the O-rings 21 in positioning the blade. However, the main purpose of the ears Z4 is to enable the shield 22 positively to stop the blade 13 at the opposite limits of its swing or oscillation. This conveniently is accomplished by providing on the side walls 19 of the body 1 along the rear portions of the apertures 13 a pair of instanding, integral or fixed abutments 25, each of which is engaged by one of the cars 24, by disposing the bottom. edges of the ears in a position to be engaged by the leading face 27 of the blade 13 at the lower limit of the latters swing and by forming on the hub la? of the blade a lug or upset engageable with the rear face of the shield at the opposite or upper limit of the blades swing. With this arrangement, the blade not only is positively limited. in the extent of its swinging, oscillating or shifting movement relative to the body 1' but, within those limits, is effectively held by friction in any position in which it is set; Further, the particular position in which the blade is set or adjusted is readily made visually determinable by providingapointer fixed to and on or in the outer face of one of the end discs and a scale 3%? etched or otherwise formed on the body alongside that disc. Also, tampering with the settin or adiustrnent of the blade is readily prevented by making the blade adjust ble only by a special tool suitably a socket wrench (not shown) fit table into a hex socket 31 extending through the hub 16 andthe discs 17 of the blade unit.

To make maximum use of the adjustability in the rate of flow of sand, through the outlet leg 9 of the sand chamher 7 made possible by the blade, it is essential that the upper surface 32 of the sand mound in the outlet leg 9 be unobstructed beyond the blade and, to facilitate calibration, desirable that the bottom edge 33 of the blade be straight and horizontal and transversely parallel to the underlying portion of the floor 15 of the sand chamber 7. To the same end, it also is desirable that the spaced sides 3 of the outlet'port ll. be straight extend upwardly at the same angle from the lip or outer edge 35 of the floor and that the lip be straight and horizontal. The desirability of horiz "itality in the lip 35 or": the floor at the outlet end ll of the outlet leg i does not require that the floor in advance of-the lip also be horizontal. n the contrary, it is desirable that the door siope downwardly toward the lip to minimize the accumulation and possible clogging of sand within the sand chamber and only necessary that the slope of the floor within the outlet leg 9 be less than the angle of repose of any sand that might be used in the sander so as not to override the regulation of the rate of flow by the blade.

With the above necessary and desirable limitations, the

elative vertical spacing or disposition of the bottom or lower edge 33 of the blade 13 and the lip 35 of the floor 15' is determinative of the depth in repose of the layer or stratum oi sand in the outlet leg 9 at any point along the door beyond the blade. Thus, with the sides and bottom of the sand layer fixed by the floor 15 and sides 34 of the outlet leg, the relative position of the blade, by regulating the depth of the layer in advance of and at the lip, will control the quantity of or rate at which the sand can flow by gravity past the lip when the equilibrium or repose is upset so that the sand can flow freely. Consequently, by mixing the sand with the actuating air beyond the sand chamber 7 and fiixing the limits of adjustment of the blade 13 such that, over the range of angles of repose of the various types of sand used in sanding, the depth of the sand in repose above the lip 35 will be zero at one limit and at maximum at the other, it should be possible for the blade to be set either to cut olf the sand entirely or to regulate precisely or exactly the quantity discharged during a sanding operation of a given duration, in all cases by varying the height of but never closing the connecting passage in the sand chamber. However, while this objective is approached in the sander of application Serial No. 43,225, it has not heretofore been attained because of the inability to eliminate entirely the action of the actuating air within the outlet leg 9, at least in the form of suction, and the consequent interference with the desired true, pure or unadulterated gravity flow of sand from the sand chamber.

It has now been discovered that the desired true gravity flow of sand from the sand chamber 7 can be obtained and this discovery has been incorporated in its preferred practical form in the disclosed embodiment of the sander of this invention. There were two main keys to this discovcry. One was as to the pressure of the actuating air. Heretofore, it has been thought that to convey sand from a sander through the'discharge pipe to the rails required to be applied to the sand at the sander at pressures on the order of 5 p.s.i. Consequently, with the line pressure available in the usual locomotive at the valve controlling the sanding operation ranging from -140 p;s.i., the size of t e sanding orifice in the control valve conventionally is made such-as to deliver air to the sandtrapat a pressure of around 5 psi. Contrary to such prior thinking, it has now been found that when, as here, the sand and air are mixed beyond the sand chamber, the sand can be conveyed effectively to the rail surface by air at a pressure at the air outlet of aroundl p.s.i. and that at such low pressure the actuating air will exert no suction on the sand in the sand chamber.

The other key was the discovery that it was possible to eliminate turbulence in the chamber in which the sand and air were mixed, here the bore 12, and consequent possible disturbance of the sand within the sand chamber, by injecting the air stream into the mixing chamber not only below the outlet port 11 of the sand chamber but also over the full width of the chamber or at least over a width that covered, embraced or included the lateral limits of the sand outlet or outlet portion 11a of the outlet port 11 occupied or tilled by sand at the maximum flow setting of the blade l3. With the air stream thus at least coextensive laterally of transversely with the overlying sand outlet 11, the effect is that, as the sand is'discharged from the outlet, it drops or falls onto and not through the stream or curtain of actuating air and without turbulence is mixed with the air and carried thereby to the outlet end of the discharge pipe.

The reduction in the pressure of the air to the desired low level 18 not readily obtainable by a f irther reduction in the size of the already small orifice in the associated control valve, nor is such a modification desirable without standardization upon a sander operable at such a low pressure. Practically, the desired low pressure should therefore be obtained by a further reduction at the sander of the pressure of the air delivered thereto from the control valve. Conceivably, this could be accomplished by use of a nozzle of special construction releasably mounted in the body 1, but it is simpler and preferred to build or form an air passage of the desired characteristics as an integral part of the body. In accordance with the preferred construction, the body 1 has at the rear adjacent the bottom of its inlet leg 2 an air inlet port 36 conveniently tapped for connection of the line (not shown) from the associated control valve and opening inwardly onto an air passage or conduit 37 in the bottom wall 38 of the body below the floor of the sand chamber 7. The air passage 37 adjacent the inlet port 36 preferably branches around a clean-out port 39 extending vertically through the bottom wall 38 and opening upwardly toward the inlet leg 8 of the sand chamber 7, suitably as opensided channels or grooves 4G in the side 41 of the cleanout port. Beyond the clean-out port 39, the air passage 37 increases very substantially in cross-section to provide an expansion chamber 42, the cross-sectional area of which, for applications of the sander to the usual locomotive system, is desirably about three times the free cross-sectional area occupied by the air as it enters the inlet port. Once increased, the cross-sectional air of the air passage remains substantially uniform to and including the air outlet or outlet port 43. As shown in FIGURE 2, the air outlet is laterally or horizontally elongated or flattened and not only parallels and includes the lateral limits of the lip 35 of the outlet port 11, but, to eliminate possible turbulence at the sides, extends substantially the full width of or is substantially coextensive with the portion of the bore or mixing chamber 12 onto which it opens. By contrast, the sand outlet lie, the lip 35 bounding the bottom of which in the illustrated embodiment lies substantially along a diameter of the cylindrical mixing chamber 12, is held within the lateral bounds of the air outlet conveniently by downwardly tapering or converging the sides 34 of the outlet port 11.

An important feature of the sander of the present invention is its ability to have its clean-out port opened for cleaning out the hollow interior of the body and closed for a sanding operation, both without the use of tools. Conventionally, the clean-out port of a sand trap is closed by a metal plug threaded into the port and applied and removed by a suitable wrench which quite often is not handy. In marked contrast, the preferred cylindrical clean-out port 39 is of uniform cross-section and smoothbored except for the interruption of its side or side wall ll by the parts of the air passage 37 opening thereonto and the related plug 4-6 is slidable axially into its seat in the bore and lockable therein by a simple manipulation of actuating means attached to it.

In its preferred form, the plug 4d includes a rigid cylindrical stem, post or centerpiece 47 having fixed to or integral or rigid with its upper end an enlarged head or peripheral flange 48, the stem being of less and the head of substantially the same diameter as the port. Surrounding or encircling and preferably slidably received on the stem 47 below and abutting against the underside of the head 48 is a rubber or like compressible cylindrical sleeve 4-9, the outside diameter of which, in uncompressed or free condition, is substantially that of the port, so that the sleeve in that condition, as Well as the head, can readily or freely be slid into the port. The stem 47 is of greater length or axial extent than the sleeve 49 and therebelow is slidably encircled by a washer 55 which, unlike the head and sleeve, is of too great diameter to fit into the port and, instead, is designed to engage the lower end of the sleeve and the surrounding underside of the bottom wall 38 of the body 1.

With the sleeve 49 contained, embraced or straddled axially by the head 48 and the washer 5t and the head and sleeve slid into the port 39 to the point at which the washer engages the bottom wall as, an inward axial force on the head and washer will compress or squeeze the sleeve and, by causing it to expand inwardly and outwardly against the confronting sides of the port and stem and to bulge into the exposed parts of the air passage 37,

not only will seal the port and the air passage but will lock the plug in the port. The necessary inward axial force is here applied by an operating handle 51 pivotally mounted below the sleeve on radial trunnions 52 carried by the stem 47 which, for ready application and removal of the sleeve and washer, preferably are the diametrically opposed ends of a pin driven radially through the stem. While the projecting arm 53 of the handle 51 provides the necessary leverage, the inward axial force is derived from a pair of integral cams 54 on the handle, one on either side of the stem. The cams 54 ride against the underor confronting face of the washer 50 and their shape is such that, when the arm 53 is swung downwardly to a sub stantially vertical release position, the sleeve is uncompressed, while on swinging of the arm upwardly, they act through the washer against the bottom wall 38 of the body 1 and through the stem 47 on the head 48 to pull the latter downwardly toward the washer until, when the arm is in its substantially horizontal locked position, the sleeve has been compressed to the extent necessary to seal the port and the exposed sides of the air passage 37.

For locking the handle in locking position so as to prevent it from being jarred to release position by service shocks, catch means are fixed to or made rigid with the underside of the washer Ell, preferably in the form of a pair of circumferentially spaced catches 55 under one or the other of which the arm 53 can slide and be locked on being swung horizontally in that direction, the spaced catches having the advantage over a single catch of accommodating the locking means to the exigencies of different installations. Additionally, to ensure that the arm 53, when swung to locked position, will be in a position to engage either catch 55, there are fixed to and formed integrally with the earns 54, at a side of the pivot opposite the arm, a pair of oppositely outstanding positioning lugs 56 which, when the handle 53 is swung downwardly, swing between a pair of preferably flat inner-sided detents or guides 57 fixed to and depending from the underside of the washer and here forming the base portions of the catches. By engagement with the detents 57, the positioning lugs 56 prevent the handle from being rotated when it is in unlocked position and ensure the proper positioning of the arm 53 relative to the catches 55 when the handle is swung upwardly to closed position.

With the combined axial extent of the head 48 and the sleeve 49 in compressed condition preferably substantially equal to the thickness of the bottom wall 38 of the body l, the upper surfaces of the plug 46 and the bottom wall will be substantially on a level when the plug is locked in the clean-out port 39 and that of the plug might then serve as part of the floor 15 of the sand chamber 7. However, in the absence of some means of cutting off sand from the sand chamber, a difiiculty would be posed in so applying the plug as to assure that there were no sand particles between it and the side 41 of the port. This difficulty is avoided by mounting in the body 1 above the clean-out port 39 a rubber or like flexible or distortable flap 58 normally closing off the outlet port from the sand chamber 7. Conveniently supported at one end on a shoulder 59 on the rear wall tl of the body 1 instanding into the inlet leg 8 of the sand chamber and screwed or otherwise fixed at that end to the body, the flap preferably is tapered toward its free end and rests at that end on the underlying portion of the floor 15 of the sand chamber in the area below the blade 13.

With an integral depending pull 61 conveniently normally received in a recess 62 in the upper portion of the stem 47 of the plug 46 and instanding, overlying stops 63 on the side Walls 19 to fix its normal position, the flap on removal of the plug may be pulled down into the clean-out port 39 to enable the interior of the sander to be cleaned therethrough and, when pushed back into its normal place or position above the clean-out port, will effectively hold the sand thereabove and prevent interference with reapplication of the plug. Too, by sloping the flap in normal posiamass-s tion downwardly toward the outlet end ll of the sand chamber '7 substantially in correspondence with the slope of the adjoining portion of the floor 15, the flap 58 in that position not only forms the part of the floor underlying the inlet leg 55 but minimizes the chance that sand will accumulate and become clogged at the bottom of that leg.

From the above detailed description, it is apparent that there has been provided an improved sander which is capable of regulating exactly the amount of sand applied during a sanding operation, of long service life and readily maintained in operating condition. It should be understood that the described and disclosed embodiment is merely exemplary of the invention and that all modifications are intended to be included which do not depart from the spirit of the invention or the scope of the appended claims.

Having escribed my invention, 1 claim:

1. A sander comprising a body, a sand chamber in said body and having connected angularly related inlet and outlet legs, blade means shiftably mounted in said body within said chamber for regulating the depth of sand in said outlet leg and therethrough the rate of discharge of sand by gravity from an outlet of said chamber, and an air outlet in said body below and at least coextensive laterally with said sand outlet, said outlets opening beyond said sand chamber onto a mixing chamber in which said sand and air are mixed during a sanding operation.

2. A sander comprising a body, a sand chamber in said body and having connected angularly related inlet and outlet legs, blade means shiftably mounted in said body within said chamber for regulating the depth of sand in said outlet leg and therethrough the rate of discharge of sand by gravity from an outlet of said chamber, an air outlet in said body below and at least coextensive laterally with said sand outlet, said outlets opening beyond said sand chamber onto a mixing chamber in which said sand and air are mixed during a sanding operation, and an air passage in said body in advance of said air outlet and including an expansion chamber for reducing the pressure of the air applied to said sander before injection thereof into said mixing chamber.

3. A sander comprising a body, a sand chamber in said body having connected angularly related inlet and outlet legs, blade means shiftabiy mounted in said body within said chamber for regulating the depth of sand in said outlet leg and therethrough the rate of discharge of sand by gravity from an outlet of said chamber, an air outlet in said body below and at least coextensive laterally with said sand outlet, said outlets opening beyond said sand chamber onto a mixing chamber in which said sand and air are mixed during a sanding operation, an air passage in said body in advance of said outlet outlet, and means in said passage for reducing the pressure of air passing therethrough prior to injection thereof into said mixing chamber.

4. A sander comprising a body, a sand chamber in said body and having connected angularly related inlet and outlet legs, blade means shiftably mounted in said body within said chamber for regulating the depth of sand in said outlet leg and therethrough the rate of discharge ofsaid by gravity from an outlet of said chamber, and a laterally elongated air outlet in said body below and at least coextensive laterally with said sand outlet, said outlets opening beyond said sand chamber onto a mixing chamber in which said sand and air are mixed during a sanding operation.

5. A sander comprising a body, a sand chamber in said body and having connected angularly related inlet and outleg legs, blade means shiitably mounted in said body within said chamber for regulating the depth of sand in said outlet leg and therethrough the rate of discharge of sand by gravity from an outlet of said chamber, a laterally elongated air outlet in said body below and at least coextensive laterally with said sand outlet, said outlets opening beyond said sand chamber onto a mixing chamber and at least coextensive laterally in which said sand and air are mixed during a sanding operation, and an air passage in said body in advance of said outlet and including an expansion chamber of increased cross-section for reducing the pressure of air passing therethrough in advance of injection thereof into said mixing chamber.

6. A sander comprising a body, a sand chamber in said body and having connected angularly related inlet and outlet legs, blade means shiftably mounted in said body within said chamber for regulating the depth of sand in said outlet leg and therethrough the rate of discharge of sand by gravity from an outlet of said chamber, a laterally elongated air outlet in said body below said sand outlet, said outlets opening beyond said sand chamber onto a mixing chamber in which said sand and air are mixed during a sanding operation, said air outlet laterally including said sand outlet and being coextensive with said mixing chamber, and an air passage in said body in advance of said air outlet and including an expansion chamber of substantially the cross-section of said air outlet and increased cross-section relative to an air inlet thereto for reducing the pressure of air passing therethrough in advance of injection thereof into said mixing chamber.

7. A sander comprising a body, a sand chamber in said body and having connected angularly related inlet and outlet legs, blade means swingably mounted in said sand chamber for regulating the depth of sand in said outlet leg, means fixed to said body and engageable with said blade means at opposite limits of the swinging thereof for positively fixing said limits, and an air outlet in said body below and at least coextensive laterally with said sand outlet, said outlets opening beyond said sand chamber onto a mixing chamber in which said sand and air are mixed during a sanding operation.

8. A sander comprising a'body, a sand chamber in said body and having connected angularly related inlet and outlet legs, a sand outlet from said chamber at an outlet end of said outlet leg, a blade unit rotatably mounted in said body, said unit including a blade shiftable within said sander for varying the depth of sand in said outlet leg, discs at opposite ends of said blade and rotatably seated in apertures in sides of said body, and friction means between said discs and body for yieldably resisting rotation of said unit, a shield releasably attached to said body above said unit and extending downwardly between said disc for preventing axial movement thereof, means on and projecting from said shield and engageable with instanding abutment means fixed to said body, said shield and projecting means being engageable with said blade at opposite limits of shifting thereof and positively fixing said limits by engagement of said projectingmeans with said abutment means, said projecting means frictionally engaging said discs for aiding said friction means in yieldably resisting rotation of said blade unit, and an air outlet in said body below with said sand outlet, s id outlets opening beyond said sand chamber onto a mixing chamber in which said sand and air are mixed during a sanding operation.

9. A sander comprising a body, a sand chamber in said body and having connected inlet and outlet legs, a sand outlet from said chamber into a mixing chamber, a smooth-bored clean-out port in a bottn wall of said body and opening upwardly toward said inlet leg, an

air passage in said body and having an outlet onto said mixing chamber below and at least coextensive laterally with said sand outlet, said having portions opening at sides onto and interrupting a side of said port, and a clean-out plug slidable axially into said port, said plug includin-" a compressible sleeve slidable in uncom pressed condition freely into said port and over s id sides of said portions, and means for a co ipressing s d sleeve within said port and said sides of said passage portions and thereby sealing said port and locking said plug in said port.

'10. A sander comprising a body, a sand. chamber in said body and having angularly related inlet and outlet legs, means for regulating the rate of discharge of sand from said chamber during a sanding operation, a cleanout port in said body below and opening upwardly toward said inlet leg, a plug slidable axially into said port, said plug including a compressible sleeve slidable in uncompressed condition into said port, a stem in said sleeve, a flange fixed to an upper end portion of said stem and overlying an upper end of said sleeve and slidable therewith into said port, a washer slidably encircling said stem below said sleeve and engageable with a lower end thereof and an underside of said body, cam means carried by said stem below and actable against said washer and on said flange means for compressing said sleeve therebetween and thereby sealing said port and locking said plug therein, an arm rigid with said cam means for swinging thereof to locking and release positions, and catch means depending from said washer and engageable with said arm in the locking position of said cam means for locking said cam means in said position.

ll. A sander comprising a body, a sand chamber in said body and having angularly related inlet and outlet legs, means for regulating the rate of discharge of sand from said chamber during a sanding operation, a cleanout port in said body below and opening upwardly toward said inlet leg, a plug slidable axially into said port, said plug including a compressible sleeve slidable in uncompressed condition into said port, a stem in said sleeve, a flange fixed to an upper end portion of said stern and overlying an upper end of said sleeve and slidable therewith into said port, a washer slidably encircling said stem below said sleeve and engageable with a lower end thereof and an underside of said body, cam means carried by said stem below and actable against said washer and on said flange means for compressing said sleeve therebetween and thereby sealing said port and locking said plug therein, an arm rigid with said cam means for swinging thereof to locking and release positions, and a pair of circumferentially spaced catches fixed to and depending from said washer and alternately engageable with said arm on swinging thereof in the locking position of said cam means for locking said cam means in locking position.

12. A sander comprising a body, a sand chamber in said body and having angularly related inlet and outlet legs, means for regulating the rate of discharge of sand from said chamber during a sanding operation, a clean out port in said body below and opening upwardly toward said inlet leg, a plug slidable axially into said port, said plug including a compressible sleeve slidable in uncompressed condition into said port, a stem in said sleeve, a flange fixed to an upper end portion of said stem and overlying an upper end of said sleeve and slidable therewith into said port, a washer slidably encircling said stem below said sleeve and engageable with a lower end thereof and an underside of said body, cam means carried by said stem below and actable against said washer and on said flange means for compressing said sleeve therebetween and thereby sealing said port and locking said plug therein, an arm rigid with said cam means for swinging thereof to locking and release positions, a pair of circumferentially spaced catches fixed to and depending from said washer and alternately engageable with said arm on swinging thereof in the locking position of said cam means for locking said cam means in locking position, and means on said cam means and engageable with means on said washer on swinging of said cam means to unlocking position for locating said arm between said catches on swinging of said cam means to locking position.

13. A sander comprising a body, a sand chamber in said body and having angularly related inlet and outlet legs, means for regulating the rate of discharge of sand from said chamber during a sanding operation, a clean- 10 out port in said body below and opening upwardly toward said inlet leg, a plug insertable in said port, and a flexible flap within said body above and normally shutting off said port from said sand chamber, said flap on removal of said plug being pullable into said port for enabling the interior of said body to be cleaned.

14. A sander comprising a body, a sand chamber in said body and having angularly related inlet and outlet legs, means for regulating the rate of discharge of sand from said chamber during a sanding operation, a cleanout ort in said body below and opening upwardly toward said inlet leg, a plug insertible in said port, a flexible rubber flap within and fixed at one end to said body above said port and normally shutting off said port from said sand chamber, and a pull depending from said flap and normally received in an upwardly opening recess in said plug, said flap on removal of said plug being pullable by said pull into said port for cleaning of the interior of said body.

15. A sander comprising a body, a sand chamber in said body and having connected angularly related inlet and outlet legs, a smooth-bored clean-out port opening upwardly through a bottom wall of said body toward said inlet leg, groove means extending transversely and interrupting a side of said here, a plug including a COID- pressible rubber sleeve slidable in uncompressed condition axially into said port, means for compressing said sleeve axially and thereby sealing said port and by bulging of said sleeve into said groove means locking said plug in said port, a flexible rubber flap within and fixed at one end to said body above and normally shutting off said port from said sand chamber, and a pull depending from said flap and normally received in an upwardly opening recess in said plug, said flap on removal of said plug being pullable by said pull into said port for cleaning of the interior of said body.

16. A sander comprising a body, a sand chamber in said body and having an outlet, means in said body for controlling the rate of discharge of sand by gravity from said outlet, an air outlet in said body below said sand outlet, said outlets opening beyond said sand chamber onto a mixing chamber in which sand and air are mixed during a sanding operation, an air passage in said body in advance of said outlet, and means in said passage for reducing the pressure of air passing therethrough prior to injection thereof into said mixing chamber.

17. A sander comprising a body, a chamber in said body for receiving sand, a passage for delivering air for mixing with sand received in said body, and an expansion chamber in said passage for reducing the pressure of air passing therethrough prior to mixing thereof with said sand.

18. A sander comprising a body, a chamber in said body for receiving sand, an air passage in said body and connectable to an air supply line leading thereto for delivering air for mixing with sand received in said cham her, and means interposed between said supply line and an outlet of said passage for reducing relative to the pressure in said supply line the pressure of the air delivered through said passage.

19. A sander comprising a body, a sand chamber in said body and having connected inlet and outlet legs, a sand outlet from said chamber into a mixing chamber, a smooth-bored clean-out port in a bottom wall of said body and opening upwardly toward said inlet leg, an air passage in said body and having an outlet onto said mixing chamber below said sand outlet, said passage having portions opening at sides onto and interrupting a side of said port, and a clean-out plug slidable axiall into said port, said plug including a compressible sleeve slidable in uncompressed condition freely into said port and over said sides of said passage portions, and means for axially compressing said sleeve within said port and thereby sealing said port and said sides of said passage portions and locking said plug in said port.

20. In a sander having a body, a sand chamber in said body and having connected angularly related inlet and outlet legs, and blade means shiftably mounted in said body within said chamber for regulating the depth of sand in said outlet leg and therethrough the rate of discharge of sand by gravity from an outlet of said chamber, the improvement comprising a laterally elongated air outlet in said body below said sand outlet, said outlets opening beyond said sand chamber onto a mixing chamber in which said sand and air are mixed during a sanding operation, and said air outlet laterally including said sand outlet and being coextensive with said mixing chamber.

21. In a sander having a body, a sand chamber in said body and having connected angularly related inlet and outlet legs, and blade means shirtably mounted in said body within said chamber for regulating the depth of sand in said outlet leg and therethrough the rate of discharge of sand by gravity from an outlet of said-chamber, the combination of a laterally elongated air outlet in said body below said sand outlet, said outlets opening beyond said sand chamber onto a mixing chamber in which said sand and air are mixed during a sanding operation, said air outlet laterally including said sand outlet and being co-extensive with said mixing chamber, and an air passage in advance of said air outlet and including an expansion chamber for reducing the pressure of air passing tneretnrough in advance of injection thereof through said air outlet into said mixing chamber.

References Cited in the file of this patent UNITED STATES PATENTS 1,686,454 Johnson Feb. 10, 1914 2,451,878 Savercool Oct. 19, 1948 2,493,452 Grigg Jan. 3, 1950 2,529,751 White Nov. 14, 1950 2,533,352 Tietig Dec. 12, 1950 2,685,379 Moeller Aug. 3 1954 2,725,247 Saari et a1. Nov. 29, 1955 2,773,619 lVloeller Dec. 11, 1956 2,905,355 Orscr Sept. 22, 1959 3,020,072 Frantz Feb. 6, 1962

Claims (1)

19. A SANDER COMPRISING A BODY, A SAND CHAMBER IN SAID BODY AND HAVING CONNECTED INLET AND OUTLET LEGS, A SAND OUTLET FROM SAID CHAMBER INTO A MIXING CHAMBER, A SMOOTH-BORED CLEAN-OUT PORT IN A BOTTOM WALL OF SAID BODY AND OPENING UPWARDLY TOWARD SAID INLET LEG, AN AIR PASSAGE IN SAID BODY AND HAVING AN OUTLET ONTO SAID MIXING CHAMBER BELOW SAID SAND OUTLET, SAID PASSAGE HAVING PORTIONS OPENING AT SIDES ONTO AND INTERRUPTING A SIDE OF SAID PORT, AND A CLEAN-OUT PLUG SLIDABLE AXIALLY INTO SAID PORT, SAID PLUG INCLUDING A COMPRESSIBLE SLEEVE SLIDABLE IN UNCOMPRESSED CONDITION FREELY INTO SAID PORT AND OVER SAID SIDES OF SAID PASSAGE PORTIONS, AND MEANS FOR AXIALLY COMPRESSING SAID SLEEVE WITHIN SAID PORT AND THEREBY SEALING SAID PORT AND SAID SIDES OF SAID PASSAGE PORTIONS AND LOCKING SAID PLUG IN SAID PORT.

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