US2301351A - Apparatus for disposing of dust - Google Patents

Description

Nov. 10, 1942.

H. J. WILLMOTT APPARATUS FOR bISPOSING OF DUST 2 Sheets-Shet 1 Filed Jan. 4, 1941 Nov. 10, 1942. H, J w L 2,301,351

APPARATUS FOR DISPOSING OF DUST Filed Jan. 4, 1941 ZSheetS-Sheet 2 Patented Nov. 10, 1942 a srr APPARATUS FOR DISPOSING OF DUST Application January 4, 1941-, Serial No. 373,153

1 Claim. (01. mm)

This invention relates to apparatus for disposing of the dust which results from theoperation of abrading machines and is herein illustrated and described as embodied in-a shoe repair machine having a dust collecting system associated with the various bufling tools with which such machines are usually equipped. The purpose of the dust collecting system is to remove dustv from the locality of operation by a suction draft and then to separate the dust from the air in which it has been entrained and to deliver the dustfree air back into. the room.

It is an object of the present invention to provide, for the purpose referred to above, an improved dust collecting system which is sufiiciently J compact to be housed within. the frame of a. shoe repair machine and which requires a minimum of power for its operation. With this object in view, the illustrated machine, is. provided with a dust hood partially surrounding an abraiding tool and with a dust settling chamberbelow the hood, with the hood opening into the chamber and affording an air passage which atall localities has a greater cross-sectional area than the. cross-sectional area of the tool. The relatively large passage enables the incoming air to travel at relatively low speed and thereby avoids stirring up dust which has settled within the chamber while at the same time requiring a minimum of power to draw the air through the passage. As illustrated herein, the several bufiing tools of the machine are provided with individual dust hoods which open into a common settling chamber through passages of relatively large cross-sectional area. These hoods, it will be noted, constitute in effect upward extensions of the settling chamber. In the upper portion of the chamber and separated from the inlet passage by a bafi'le is an outlet conduit which leads to the intake of a fan while the exhaust from this fan leads to a filter bag. The air leaving the settling chamber by the way of said outlet conduit is relatively free of dust andthe small amount of dust'still entrained therein is substantially all removed as it passes through the filter bag.

These and other features of the invention will be described as embodied in an illustrative machine and pointed out in the appended claim.

Referring now to the accompanying. drawings,

Fig. 1 is a front elevation of a shoe repair machine provided with an improved dust collecting system;

Fig. 2 is an end elevation of the machine shown in Fig. 1 looking in the direction of the arrow II;

Fig. 3 is a verticalsection ofthe machine taken on the line III-III of Fig. 1;

Fig. .4 is a vertical section taken on theli-ne IV'IV of Fig. l; and

Fig. 5 is an enlargement of a portion of Fi ,4 showing the dust-hood.

The supporting structure of the illustrated machine consists of three upright frame members l9, l2 and I4 connectedby fourhorizontal members l6, l8; 26) and 22. which extend lengthwise. Carried by and above this frame structure is a shelf 24.

Theoperating instrumentalities of the machine include a plurality of brushes and other cleaning tools 26 for cleaning and polishing shoes, these tools 26 being carried upon a horizontal shaft 23 which, is journaled in bearings 30 supported by the frame structureof the machine. The bearings 30 are carried by supports 29which are adjustable up and down in split sockets provided with clamping bolts 3| (Fig. 2) to secure the supports in desired positions of heightwise adjustment. The tools 26 are backed by a; sheet metal guard 33. Other operating instrumentalities comprise three heel bufling wheels 32 and: a bottom bufiing roll 34 all mounted upon a shaft 35 which is journaled in bearings 38 supported by the frame structure of the machine. The bearings 38 are carried by supports 31 which are slidable up and down in split sockets provided with clamping bolts 39 (Fig. 3) to secure the supports in desired positions of heightwise adjustment. As illustrated herein, the shafts 23 and 36 are at about the same level and are arranged above the forward portion of the frame structure at a convenient height for the operator. Associated with each of the heel bufiing wheels 32 is an individual dust hood it and associated with the bottom scouring roll 34 is a dust hood. 42'. All of, these dust hoods open downwardly into a common settling chamber 44 (Fig. 4) which occupies the space between the upright frame members l2 and I i-within the frame structure of the machine. The settling chamber 44 issupported by'metal straps. 46 (Figs. 1 and 4) secured around: the

longitudinal framemembers 22 and I6. Air is withdrawn from the chamber 44 through an outlet conduit' 48-by a fan 59, the discharge end of said fanbeing connected to a conduit 52 which leads to a filter 540i a suitable fabric for screening fine dust. This filter is conveniently rectangular in cross section and hangs from a metal top plate 55 which is supported by straps 58 secured around the longitudinal frame members 22 and I8. The lower end of the filter is secured to a rectangular bottom plate 55 (Fig. 1) the central portion of which is cut out, leaving only a continuous rim around the four sides. The front portion of this plate is supported by two tie rods 51 secured at their upper ends to the top plate 56 and extending downwardly within the filter.

.The rear portion of the plate 55 is supported by illustrated in Figs. 4 and 5. As shown in thosefigures, the hood 4!] has a rear wall 60 which extends upwardly from the top of the chamber 44 and forwardly over the bufiing wheel 32.

hood 40 is provided also with a pair of parallel 4 side walls 62 which are spaced closely to the respective faces of the wheel 32, and with a forwardly and laterally flaring throat 64 below the wheel. The side walls 62 are notched to clear the shaft 36. A hinge 65 enables the upper portion of the hood to be swung upwardly and backwardly when access to the wheel 32 is desired. The rear wall .66 together withthe side walls 62 and the throat 64 define a passageway which extends downwardly into the chamber 44 and all portions of this passageway have across-sectional area which is greater than that of the cross-sectional area of the wheel. Furthermore, the Width of this air passage measured forwardly and rearwardly is greater than the diameter of the wheel.

A further feature of the hood structure consists in the provision of a pair of interior vanes 66 and 68, and also two partitions l0 and 12. The vanes 66 and 68 are located at the rear of the wheel 32, their forward portions being spaced closely to the periphery of the wheel and almost tangent thereto. The vane 66 has a forward portion 61, and the vane 68 has a forward portion 69. Each of these forward portions extends upwardly and rearwardly in a straight line, or rather a plane, which is perpendicular to a radius from its forward edge to the axis of the tool shaft 36, said forward edge being as close to the tool 32 as clearance permits. The remaining portion of each vane continues from the forward portion in a smooth curve which extends first upwardly and rearwardly, then rearwardly, and then rearwardly and downwardly. The rearwardly and downwardly extending portion of the lower vane 66 is considerably longer than that of the upper vane 68. It will be noted that the vanes 66 and 68 do not extend all the way to the rear wall 60, but leave ample passageways for the flow of air adjacent to the rear wall. The partition 10, however, which is curved similarly to the vanes 66 and 68, begins as closely to the tool 32 as clearance permits and extends all the way to the rear wall f to close the upper portion of the dust hood. The

partition 12 begins at the forward edge of the partition 10 and extends in an are about the tool 32 to the forward edge of the rear wall 6!], being spaced as close to the periphery of the tool 32 as clearance permits. The partitions 10 and I2 and the rear wall 66 thus completely enclose a dead air space 14. Functionally, therefore, the partitions 10 and 12 may be regarded as constituting the upper portion of the rear wall of the dust hood, the rear wall 66 being continued over them merely for considerations of construction and appearance.

The hood 42 while differing in dimensions from 78,

vertical baffle I6.

the hoods 40 is similar in construction to those hoods, and is provided with similar vanes and partitions.

The several dust hoods, by reason of the construction above described, can operate efficiently with a minimum of suction induced by the fan 50 within the chamber 44-. Referring to Fig. 5, it is evident that the rotation of the tool will set up a current of air leading into the opening of the throat 64, and that this current will draw additional air with it over the lip of the throat. Much of the dust resulting from the operation of the tool will be impelled, by the rotation of the tool itself, into the throat opening; and substantially all of the remaining dust will be drawn in by the entering air. Most of this dust continues its downward movement through the hood. A portion of it, however, is entrained in the peripheral air current set up by the rotation of the tool 32 or becomes embedded in the abrasive material of the wheel. The major portion of the peripheral current is deflected from the tool by the forward portionfi'l of the vane 66, and is directed downwardly, with a minimum of disturbance, by the curved portion of the vane. A small amount of entrained and embedded dust, however, may pass through the clearance space between the forward portion 61 and the periphery of the tool. The stationary straight portion 61, however, being close to the periphery of the tool, will exert a powerful frictional effect upon the moving film of air, giving rise to turbulence within the film that exerts a scouring action tending to remove any dust clinging to or embedded in the abrasive material of the tool. Moreover, the gradual flaring of the space between the vane and the tool produces the effect of an expansion nozzle; the thin peripheral film of air with entrained dust expands until most of it is'rem'oved from the direct influence of the rotating tool. The vane 68, with its forward portion 69, will operate in the same way upon the small amount of dust that passes the vane 66; and the partition 10 will direct downwardly the almost negligible amount of dust which passes the vane 68. As a further precaution against even a small amount of dust escaping from under the forward end of the rear wall 60, the partition 12, extending over a wide are close 'to the periphery of the tool, exerts sufiicient friction to block effectively the passage of air between it and the tool. It is therefore evident that the hood 40 V by reason of its construction, and without depending upon suction, is capable of gathering the dust generated by the operation of the tool, directing this dust downwardly in a quiet stream,

' and preventing any of it from escaping over the top of the tool.-

The. interior ofthe upper portion of the settling chamber 44 is divided longitudinally by a The lower ends of the rear Walls 69 of the various dust hoods are continuous with the baflle 16. A pair of flanges 78 on the respective ends of the braille-16 provide for securing the baiiie to the end wall of the chamber 44. The baffle 16 terminates a considerable distance above the bottom of the chamber 44, said distance being greater than the space between the bafile 16 and the front wall of the chamber. The lower end of the baflle is curved forwardly as indicated by the reference character 66. The outlet conduit 48 extends into the chamber 44 along the full length of the chamber at the high est pant of the chamber and back of the bafiie l6. Along the top of that portion of the conduit 43 tling begins at once.

which is within thecham'ben'is an orifice 82 through which air from the chamber enters the conduit. 4 The-cylindrical wall of the conduit at the edges of the orifice 82 is flanged upwardly and away fromthe-orifice-as indicated by the reference numeral 84 to prevent any dust deposited upon the conduit from being swept into the orifice. In the front wall of the chamber M atthe lower portion thereof is 'a pair of'doors 86 which, may be opened to provide access for cleaning out the deposit of dust. 3

The power for driving the tool shaft and the fan is derived from a motor 88 secured upon a 'bracket'89 which in turn is pivotally mounted upon the horizontal frame member I8. The bracket 89 is secured in any desired position of heightwise adjustment by an extensible rod 90, the upper and lower ends of which are pivotally connected to the bracket and the frame member I6 respectively. A belt 92 running under a pulley 94 on the motor shaft and over a pulley 96 on the shaft 28 drives the cleaning tools 26. On the motor shaft is a second pulley 98 which drives a belt I00. From the pulley 98 the belt I is looped about a pulley I 02 on the shaft of the fan 50, thence about a pulley I04 0n the shaft 36, thence about a pulley I06 close to the pulley I02 on the fan shaft and thence around a pulley I08 close to the pulley I04 on the shaft 36. Between the pulleys I02 and I08 the belt makes a single loop around the pulley 98. The belt I00 is of'the type known .as a V-belt, having the cross-section of a truncated triangle, and it may be given an initial twist of 360, before the ends are joined, to avoid a twist after the belt is assembled upon the pulleys. An advantage of the arrangement of the belt and pulleys as described above resides in the fact that by providing two pulleys on the shaft 36 and also two pulleys on the fan shaft, the necessary belt traction can be obtained by the use of pulleys small enough to give a desirable speed ratio between the motor and the tool shaft.

In assembling the machine the bearing supports 31 are first adjusted to the exact height to bring the several bufling tools into proper relation to their respective dust hoods, this adjustment being critical because of the close clearances heretofore mentioned. The motor supporting bracket 89 is then adjusted up or down by varying the length of the rod 90 until the desired tension in the belt I00 has been obtained. The bearing supports 29 may then be adjusted up or down to give the desired tension in the belt 92.

When the machine is in operation, dust laden air will enter each of the various dust hoods between the tool and the associated throat 64. As soon as this current of air has passed the tool its velocity will diminish considerably in View of the large cross-section area of the passageway leading down into the settling chamber. Because of this large cross-sectional area the movement of the air is relatively slow and the process of set- The hood therefore may be regarded as an upward extension of the settling chamber. The velocity of the downwardly moving air within the chamber below the hoods will be slight because of the relatively great cross-sectional area of the forward portion of the chamber, that is, the portion which is forward of the bafile I6. The greater part of the dust entrained in the entering air will thus settle to the bottom of the chamber 44. The air in the forward portion of the chamber will then pass under the bafile I6, the space between the lower edge of the baffle and the bottom of the chamber being amply sufficient to avoid increasing the velocity of the air and thereby stirring up the dust which has been deposited. The outlet conduit 48 is positioned as high as possible above the level of the settling dust and the upward current of air in the portion of the chamber rear of the baffle '16 will move with low speed to the orifice 82. The smallamount of duststill entrained in this air will be carried through the fan 50, and thence into the filter bag 54. The pressure developed byythe fan" 50 need'be-little more than enough to vovercome the back pressure of the filter and the friction in the conduits 48 and. 52' and through the orifice 82. Because of the relatively small amount of dust entrained in the air a filter bag of moderate dimensions is sufficient to effect separation of the dust to the required degree. Furthermore, because of the relatively small volume of air handled, and because of the fact that this air is delivered downwardly at low speed through the center of the plate 56, much of the dust entrained in the air entering the filter bag will settle before reaching the walls of the bag. The amount of dust to be screened as the air passes through the filter material is therefore small indeed. In view of these considerations, it becomes evident that the filter bag may be made much smaller than would otherwise be expected. There is ample room within the frame structure between the upright members [0 and I2 not only for such a filter bag but also for the motor 88 and the pulleys 94 and It is evident, from the above description, that the apparatus operates by using a small volume of air, only enough to entrain the dust generated at the locality of operation and to carry this dust into the hoods, and by moving this air at a relatively low speed through the settling chamber and through the filter, allowing the dust to settle of its own accord rather than attempting to separate it forcibly from the air in which it is entrained. This principle of operation, as contrasted with centrifugal separation, or with systems wherein high air velocity and abrupt changes of direction are relied upon, calls for a minimum expenditure of power and at the same time affords an opportunity for the dust to settle naturally. The apparatus described herein requires no power to create a strong suction at the hoods to prevent the escape of dust over the top of the tools, and it requires no power to speed up the air current for the purpose of dust separation, but only enough power to overcome the back pressure of the filter and the friction of the air in passing through the apparatus. In avoiding high speed of the air current, any tendency to stir up dust already deposited is avoided, and the dust is given every opportunity to settle. The settling of the dust begins immediately upon the entry of the air into the hoods, and it continues during the slow descent of the air within the settling chamber.

Further settling takes place in the filter bag.

By far the greater proportion of dust is thus separated by settling, and only a relatively small amount by filtration. Because of this fact, and because of the small volume of air handled, the filter, as has already been pointed out, may be relatively small. Furthermore, the small amount of air passing through the entire apparatus, and the utilization of the additional space afforded by the dust hoods and filter bag for settling, enable the apparatus to be made more compact than might at first be expected. The apparatus thus ofiers the two advantages of low power consumption and of compactness, both of which are of the highest importance when the apparatus is to be used in connection with a shoe repair machine.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States is: v

A dust settling chamber suitable for use in shoe repair machines, comprising a closed ,receptacle, a row of openings extending lengthwise along the top of said receptacle for connection to individual dust hoods for the various tools of the machine, an exhaust conduit arranged lengthwise in the upper portion of said receptacle and extending outside of said receptacle, said conduit being substantially cylindrical and having a lengthwise. orifice along its top within the receptacle for the admission of air from the receptacle, the wall of said conduit being flanged upwardly and away from the orifice on each side of the orifice to prevent dust deposited on the conduit from being swept into the conduit, and a baflie within the vreceptacle and extending downwardly from the top thereof between said conduit and said openings.

HERBERT J. WILLMOTT.

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