US3121621A - Rotary tiltable drum dryer - Google Patents

Description

Feb. 1 8, 1964 w. H. JACKSON 3,121,621

ROTARY TILTABLE DRUM DRYER v Filed May 16, 1962 3 Sheets-Sheet l INVENTOR.

iff@ zO/62 Feb. 18, 1964 W. H. JACKSON ROTARY TILTABLE: DRUM DRYER Filed May 16, 1962 3 Sheets-Sheet 2 IN VENTOR.

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#T7 Ausf/gs' Feb. Y 18, 1964 w. H. JACKSON 3,121,621

ROTARY TILTABLE DRUM DRYER INVENTOR. J'dc/soy-r TT NLO/fsf United States Patent O 3,l2l,621 ROTARY TLTABLE DRUM DRYER William H. Erickson, Birmingham, Mich., assigner to The Udylite Corporation, Detroit, Mich., a corporation 'of Delaware Filed May i6, 1%2, Ser. No. 195,112 2 Claims. (Cl. S14- 126) The present invention broadly relates to drying apparatus and more particularly to an improved rotary and tiltable dryer mechanism for achieving rapid and eliicient drying and separation of relatively small metallic workpieces having an exceptionally high surface area per unit volume.

A large number of liquid treating processes such as electroplating operations, for example, are commercially employed for cleaning and treating metallic workpieces. In some instances it is necessary to dry the workpieces between intervening processing steps as well as at the completion of the treating cycle. While a large number of different dryer constructions have heretofore been used or proposed for use in connection with drying workpieces subjected to liquid treating processes, such dryer constructions have been found inadequate for efciently drying workpieces which are of a relatively small size and which possess a comparatively large surface area per unit volume. This is particularly true of small workpieces such as metallic tabs, electrical connectors, electrical contacts, and the like, which are formed in small substantially fiat configurations and have a tendency to adhere to each other as the result of the liquid on the surfaces thereof. The adherence of the workpieces prevents efficient drying thereof and frequently results in relatively iirm adhesion of the workpieces necessitating painstaking separation thereof. This condition is further aggravated when the small flat thin workpieces are provided with indentations therein effecting a further entrapment of the liquid and thereby further increasing the ditiiculty of drying the workpieces. Because of the adherence of such small workpieces to each other and the large surface area thereof per unit volume, the drying of such workpieces in conventional centrifugal-type dryers or kiln-type dryers has proven to be inefficient and the resultant workpieces frequently are found to possess a residuary liquid content on the surfaces thereof. Other drying techniques of the types heretofore known have also been found to be inadequate for providing a substantially complete drying of the workpieces within a reasonable time. In some instances, the drying apparatus heretofore known produces an objectionable degree of surface injury to the workpieces during the drying operation and may also result in the formation of surface stains. In some dryers, absorbent materials such as sawdust, ground-up corn cobs, and the like are mixed with the workpieces in order to promote drying thereof. The elimination of the use of such absorbent materials in accordance with the dryer comprising the present invention overcomes the problem of separating the workpieces from the materials at the completion of a drying cycle which in many instances is extremely difficult and time consuming.

It is accordingly a primary object of the present invention to provide an improved rotary and tiltable dryer which overcomes the disadvantages of dryer apparatuses of the types heretofore known and achieves quick and eiiicient drying and separation of relatively small workpieces.

Another object of the present invention is to provide an improved rotatable and tiltable dryer apparatus wherein the workpieces are gently tumbled within an angularly inclined perforated drum effecting separation of the individual workpieces in spite of the adhering tendency thereof achieving thereby optimum drainage and drying characteristics and preventing entrapment of residuary lCe liquid within the mass of the workpieces without requiring the use of extraneous absorbent materials..

Still another object of the present invention is to provide an improved rotatable and tiltable dryer apparatus in which relatively small workpieces can readily be loaded in bulk form and readily discharged therefrom without incurring any objectionable degree of relative surface abrasion therebetween.

A further object of the present invention is to provide an improved rotatable and tiltable dryer apparatus which is of an integral and compact design and construction, of durable operation, and of simple and economical manufacture and use.

The foregoing and other objects and advantages of the present invention are achieved by providing a framework having a perforated rotatable drum disposed within an encircling shroud in which the drum rotates and the entire assembly of which is tiltable about an axis disposed transversely of the axis of rotation of the drum for enabling loading and unloading of the workpieces therein and for achieving the optimum tumbling action. An integral duct and heating system is mounted on the framework for circulating a heated drying fluid such as air into the open end of the drum during the drying operation and which is drawn through the perforations in the cylindrical wall thereof as well as in the base thereof. A portion of the air is recircuiated through the duct system which is provided with blower means and heating means for reheating the circulated and makeup air to a preselected temperature after which it is again discharged into the drum of the dryer.

Other objects and advantages of the present invention will become apparent from the following detailed description taken in conjunction with the accompanying drawings, wherein:

FIGURE l is a side elevation View partly in section of the dryer apparatus constructed in accordance with the preferred embodiments of the present invention and showing the drum and air discharge nozzle in the operative drying position;

FIG. 2 is a front elevation view of the dryer apparatus shown in FIGURE l with the drum cover partially broken away for clarity;

FIG. 3 is an end view of thedrum and shroud assembly and the drive means for effecting controlled rotation of the drum; and

FIG. 4 is a fragmentary elevation view of the drum tilting mechanism.

Referring now in detail to the drawings and as -may be best seen in FIGURES l and 2, the dryer apparatus comprising the present invention includes a box-like framework comprising four upright corner members 6 having theV lower ends thereof securely aiixed to a base 8 and the upper ends thereof to a top frame 10. A pair of intermediate side members 12 extend between opposite pairs of the corner members 6 at a point intermediate the ends thereof on which the rotatable and tiltable drum assembly is mounted.

The drum assembly as best seen in FEGURES 1 3 comprises a U-shaped frame or yoke 14 comprising a pair of substantially parallel side members 16 of a channelshaped cross section which are rigidly secured together by a pair of channel-shaped bight members 1S at their inner end portions. Trunnions 2da, Zlib are rigidly aliixed to each of the side members lof the yoke 14 and project laterally outwardly therefrom. Each trunnion 29a, Ztl/5 is rotatably supported within a bearing or pillow block 22 aliixed to the side members 12 of the box-like framework. The longitudinal axes of the trunnions Elia, 2Gb are disposed in axial alignment providing for relative pivoting or tilting movement of the yoke and the rotatable drum assembly carried thereon enabling angular positioning of the axis of the drum and tilting movement of the drum assembly as required during a loading, unloading, or drying operation. l

A shaft 24 extends substantially through the midpoint of the bight members 18 of the yoke 14 and parallel to the side members 16 thereof and is rotatably journaled in a pair of bearings 26 affixed to the bight members. The forward end of the shaft 24 is provided with a squareshaped drum support plate 28 including a tubular sleeve 30 through which the forward end portion of the shaft 24 extends and which is securely fastened thereto such as by welding, for example. A series of triangularly shaped reinforcing ribs 32 extend radially from the sleeve 30 toward the periphery of the support plate 28 and are rigidly welded thereto maintaining the support plate in a position substantially perpendicular to the axis of the shaft 24. The support plate 28 is provided with four apertures 34 therethrough for facilitating the circulation of air through the rotatable drum in a manner as will be subsequently described.

The opposite end of the shaft 24 is provided with a driven sprocket 36 and is affixed thereto such as by a key and around which a exible element such as a chain .33 is trained having another portion thereof trained about a driving sprocket 40 mounted on the output shaft 42 of a speed reducer 44. The speed reducer 44 is provided with an input shaft 46 which is coupled to an electric motor 48. The electric motor 48 and the speed reducer 44 are adjustably mounted on a mounting plate 50 aixed to a frame 52 projecting upwardly from and securely axed to the bight members 18 of the yoke 14.

A rotatable perforated drum 54 is removably secured to the support plate 28 and is rotatable thereby at a preselected speed in accordance with the speed of rotation of the motor 48 and the speed reducer 44. The drum 54 comprises a circular perforated base 56 having a spider Yor cross 58 securely affixed to the outer surface thereof.

The outer extending portion of each arm of the spider 5S is provided with a threaded boss 60 for removably securing the drum 54 to the support plate 28 by means of screws 62. A guide boss 64 is securely affixed to substantially the center of the spider 58 for slidably receiving the forward projecting end of the shaft 24 facilitating axial alignment of the drum relative to the support plate and the shaft 24.

The side Wall of the drum 54 is comprised of a substantially cylindrical perforated sheet 66 which is securely welded or otherwise fastened to the periphery of the base 56. The outer and inner ends of the cylindrical sheet 66 are preferably reinforced by hoops 68 extending around the periphery thereof and rigidly affixed thereto. The interior of the drum 54 as defined by the perforated base 56 and perforated cylindrical sheet 66 is formed so as to provide a lsmooth uninterrupted surface in order that the small workpieces disposed therein during a drying operation will not catch or otherwiseV become engaged by irregularly shaped projections. It is also contemplated that one or more longitudinally disposed circumferentially spaced tumbling ribs 70 can be provided along the interior of the cylindrical sheets 66 as shown in FIG. l to impart a gentle tumbling action to the workpieces in response to rotation of the drum facilitating separation and drying of the workpieces. Y

The base 56 and the cylindrical sheet 66 comprising the drum 54 are perforated with small holes so as to facilitate the movement of drying air entering the drum through the workpieces contained therein and out through the perforations between an annular area formed between the periphery of the drum 54 and a cylindrical impervious shroud 72 disposed therearound. The cylindrical shroud V72 is affixed to the inner surfaces of the side members 16 of the yoke 14 and is disposed substantially concentrically around the drum 54. The outer end of the shroud 72 is provided with an inwardly extending annular ange '74 which terminates in clearance relationship from the periphery of the hoop 68 extending around the outer peripheral edge of the drum 54. The close relationship between the edge of the flange 74 and the drum 54 minimizes a bypassing of unheated outside air directly to the annular region between the shroud 72 and the periphery of the drum 54.

A cover 67 is preferably removably installed over the inlet to the drum to reduce the back-blast of a heated drying uid discharged therein. The cover as shown in FIGURES l and 2 comprises a circular plate 69 having an aperture or port 71 therein through which the drying uid is injected. A transverse strap 73 is rigidly secured to the face of the plate 69 to which a pair of handles 75 are secured for facilitating installation and removal of the cover 67. The projecting end portions of the strap 73 are formed with engaging slots 77 which are adapted to be aligned with and removably engaged by the shank and head portions of screws 79 axed to and projecting from the ends of suitable counterweights 81 secured to the ends of the side members 16.

The lower rearward end portion of the shroud 72 extends inwardly within the box-like framework so that any liquid draining from the workpieces contained within the drum when the drum is in the operative position as shown in solid lines in FIG. l drains and drips downwardly into a receptacle or sump generally indicated at 76 disposed within the base of the framework. The sump 76 is defined by a forwardly inclined base 7S, a rear wall 80, a pair of side walls 82 and a forward wall 84 which is provided with a drain tube 86 adjacent to the base thereof for periodically or continuously withdrawing liquid therefrom.

The rear wall 8i) of the sump 76 is provided with an aperture therethrough to which an outlet duct 38 is axed which is disposed in communication with the inlet of a centrifugal blower 9i? mounted on a framework 92 affixed to the corner members 6 of the box-like framework as best shown in FIGURE 1. The centrifugal blower 90 is driven by means of a belt 94 drivingly connected to an electric motor 96 mounted beneath the blower on the framework 92.

The discharge side of the blower 9() is connected to a transition duct 98 which is secured to the inlet side of a heating chamber 190 which is provided with suitable heating elements such as steam coils 102 for heating the air passing therethrough to a preselected temperature. When steam coils such as the steam coils 102 are ernployed for heating the drying air passing therethrough, appropriate regulation of the outlet temperature of the air as indicated by a temperature indicator 101 can readily be controlled by regulating the pressure of the steam supplied thereto by a pressure control valve 103. The air leaving the heating chamber 100 passes into a transition duct 104 which is provided at the outlet end thereof with a hinged duct 106 formed at its outlet end with a rectangularly shaped nozzle 108. The hinged duct 106 is mounted for relative swinging movement from a position as shown in solid lines in FIG. 1 to an inoperative position as fragmentarily shown in phantom outwardly spaced from the operative position by means of a hinge connection 119 in order to enable the duct to be disposed in a clearance position enabling tilting movement of the drum assembly to and from the operative position and an unloading position.

The hinged duct 106 is movable by gravity to the operative position shown in solid lines in FIG. 1 in which the nozzle end projects through the port 71 in the cover 67 and is retained in the inoperative position by a latching arrangement including a pivotally mounted lever arm 112V ing the tang 114 from the pin 116 enabling downward swinging movement of the hinged duct so that the nozzle 163 at the discharge end thereof is disposed Within the interior of the drum 54.

Tilting movement of the drum assembly to and from an operative position as shown in solid lines in FIG. 1 to an inoperative or dumping position as fragmentarily shown in phantom is achieved as hereinbefore described by means of the trunnions 20a, 20b rotatably journaled in the pillow blocks 22 mounted on the side members 12 of the box-like framework as best seen in FIGURES 2 and 4. The tilting movement of the drum assembly including the yoke 14 and the power means thereon for effecting rotation of the drum can be simply achieved by a driven gear 118 keyed or otherwise affixed to the projecting shank of the trunnion 26h which is disposed in meshing relationship with a pinion 12d afiixed to a shaft 122 rotatably secured on the corner member 6 adjacent thereto as best shown in FIGURES 2 and 4. The shaft 122 is provided with a handle or crank 124 for rotating the pinion gear and in turn effecting tilting movement of the drum assembly. A suitable latching pawl 126 is pivotally mounted on a plate 128 adjacent to the pinion 120 as shown in FlGURE 4 and is manually movable to and from an engaging position and a nonengaging position with the gear teeth on the periphery of the pinion 120 so as to retain the drum assembly in the appropriate angularly inclined or tilted position. It will be appreciated by those skilled in the art that alternate satisfactory tilting mechanisms such as a worm drive assembly can be satisfactorily employed for effecting tilting movement of the drum assembly.

In the specific dryer construction shown in the drawings, the trunnions Zita, 2Gb are affixed to the side members of the yoke 14 at a position such that distribution of weight of the drum assembly tends to pivot the drum toward the operative position as shown in solid lines in FGURE l. Accordingly, to tilt the drum assembly to the dumping position as shown in phantom in FIGURE l, the crank 124 is rotated in a clockwise direction as viewed in FIGURE 4 until the appropriate tilt has been attained and thereafter the latching pawl 125 is placed in engaging relationship to maintain the drum assembly in the dumping position until substantially all of the workpieces have been dumped therefrom into a suitable receptacle or transfer conveyor mechanism.

In operation, and with the drum assembly in the loading and operative position as shown in solid lines in FIG- URE 1, the blower motor 96 and the drum motor 4S are energized by closing a pair of suitable motor control switches 136 mounted on a control box 132 affixed to the upper right side of the framework as viewed in FIGURE 2. Accordingly, air commences to circulate through the duct 88, the blower 90, the heating chamber i) and is discharged through the nozzle 108 in the hinged duct 196 which is disposed in the downward operative position projecting into the drum through the cover as shown in solid lines in FIGURE l. The air is heated to the appropriate temperature, as indicated by the temperature indicating device 101 mounted in the outlet side of the heat chamber 10i) by introducing steam into the steam coils 162 by opening the pressure regulator valve 104 to achieve the desired steam pressure. Accordingly, air is drawn from the interior of the sump 76 out through the outlet duct 55. The suction created in the sump 76 as a result of the rotation of the blower facilitates the movement of the heated air discharged from the nozzle 103 into the interior of the drum, through the workpieces therein, and out through the perforations therethrough into the annular chamber defined by the cylindrical shroud 72 and thence down into the sump '76.

To prevent an excess of external air from being drawn into the sump 76, a lateral angularly inclined baiiile 138 is provided which extends transversely above and between the side walls 82. and rear wall S0 of the sump. The

arrangement as shown is effective to recirculate about 50% of the heated air discharged into the drum along with 50% of new makeup air of a relatively lower temperature and humidity which are subsequently mixed and reheated in the heating chamber 100. The.` proportion of the initial heated air to be recirculated can be increased by providing a Vfiexible sheet such as an accordion pleated boot as best seen in FIGURE 1, which has the upper edge thereof affixed to the lower peripheral portion of the cylindrical shroud 72 and the lower portion thereof affixed to the arcuate upper edge 142 of the front wall 84 of the sump 76. By virtue of employing the boot 149 a greater proportion of the air drawn through the drum 54 is drawn into the `sump 76 and recirculated through the heating chamber 100.

For most drying operations, it has Ibeen found that satisfactory circulation and passage of air through the Workpieces and through the perforations in the drum 54, has been obtained when the perforations comprise between about 30% to about 40% of the total internal surface area of the drum. However, the percentages of open area of the drum 54 can be varied in accordance with the specific nature of the workpieces to be dried to achieve optimum drying characteristics depending upon the particular shape, size, and surface configuration of the parts.

Rotation of the drum 54 is controlled in speed so as to achieve a gentle tumbling action of the Workpieces without effecting a high surface-to-surface rubbing engagement which might otherwise produce damage to a surface coating such as an electrodeposited plating. Drum speeds ranging from about 30 to about 40 r.p.m. have been found eminently satisfactory for most purposes. rIhe gentle tumbling action imparted to the workpieces also effects a separation thereof and re-exposure of moisture-coated surfaces assuring substantially complete drying thereof.

At the completion of the drying operation, the hinged duct 106 is pivoted to the inoperative position as shown in phantom in FIGURE 1 and maintains that position by the engagement of the latch mechanism. The cover is removed and the crank i124 is thereafter rotated effecting tilting movement of the drum assembly to the dumping position as shown in phantom in FIGURE l, whereby the dried workpieces therein are discharged into a suitable receptacle or transfer conveyor.

It will be apparent from the foregoing description that the compact and integral construction of the dryer enables movement thereof to any desired location in a manufacturing plant providing increased flexibility and versatility and achieving an optimum Iutilization of plant facilities and material handling.

While it will be apparent that the preferred embodiments herein illustrated are well calculated to fulfill the objects above stated, it will be appreciated that the invention is susceptible to modification, variation and change without departing from the proper scope or fair meaning of the subjoined claims.

What is claimed is:

l. A dryer comprising a framework, a receptacle in the base of said framework, a drum assembly mounted on said framework disposed above said receptacle, said drum assembly comprising a yoke-shaped frame including a bight portion and a pair of side members, a shaft rotatably journaled in said bight portion and extending substantially centrally of and parallel to said side members, a cylindrical perforated drum having a perforated base and an open end mounted on said shaft at said base thereof, an imper-forate cylindrical shroud on said frame encircling the periphery of said drum forming an annular space therebetween, a motor on said frame, means drivingly connecting said motor and said shaft for effecting rotation of said drum about its longitudinal axis, a tr-unnion on each of said side members projecting laterally thereof and disposed in axial alignment with each other, bearing means on said framework 4for rotatably supporting said trunnions enabling pivotable tilting movement of said drum to and from an upwardly inclined drying position and a downwardly inclined unloading position, and crank means on one of said trunnions for effecting tilting movement of said drum assembly, a blower on said framework, a duct extending between said blower and said receptacle and disposed in communication with the interior thereof, a heater in said duct for heating the air therein to a preselected elevated temperat'ure, a conduit disposed in communication with said blower including a hingedly mounted nozzle thereon movable to and from an operative position wherein its outlet end is disposed in the interior of said drum when in sa-id drying position effecting movement of air through the interior of said dr-um out through the perforations therethrough and into said annular space therearound to an inoperative position angularly spaced from said operative position and in clearance relationship from said drum enabling unobstructed pivotable tilting Imovement thereof.

2. A dryer comprising a framework, a receptacle in the base of said framework, a drum assembly mounted on said framework and disposed above said receptacle, said drum assembly comprising a yoke-shaped frame including a bight portion and a pair of side members, a shaft rotatably journaled in said bight portion and extending substantially centrally of and parallel to said side members, a mounting plate affixed to said shaft, a perforated cylindrical drum including a perforated base and formed with an open end positioned with said base thereof removably secured to said mounting plate, an imperforate cylindrical shroud on said frame encircling the cylindrical periphery of said drum forming an annular space therebetween, a motor on said frame, a sprocket on said shaft, means drivingly connecting said motor and said sprocket for etfect ing rotation of said drum about its longitudinal axis, a

trunnion aixed to and extending laterally of each of said side members and disposed in axial alignment to each other, bearing means on said framework for rotatably mounting said trunnions providing for tilting movement of said drum assembly about an axis transverse to the axis of said drum to and from an upwardly inclined drying position and a downwardly inclined unloading position, and coacting gear means including crank means associated with one of said trunnions and said framework for effecting tilting movement of said drum assembly between said positions, a duct on said framework having one end thereof disposed in communication with the interior of said receptacle, a heater in said duct for heating the air circulated therethrough to a preselected elevated temperature, a blower in said duct for withdrawing air from the interior of said receptacle and the interior of said drum out through the perforations therethrough and through said annular space therearound, an outlet nozzle disposed in communication with said duct and movable to and from an operative position for discharging the heated said air into the interior of said drum when in said drying position and an inoperative position spaced therefrom enabling unobstructed tilting movement of said drum assembly, and latching means on said framework for removably latching said nozzle in said inoperative position.

References Cited in the tile ofV this patent UNITED STATES PATENTS 1,548,036 Greene Aug. 4, 1925 2,253,047 Purkett Aug. 19, 1941 2,643,463 Grantham June 30, 1953 2,906,035 Y De Moss Sept. 29, 1959 3,067,986 Grantham Dec. 11, 1962

Claims (1)

1. A DRYER COMPRISING A FRAMEWORK, A RECEPTACLE IN THE BASE OF SAID FRAMEWORK, A DRUM ASSEMBLY MOUNTED ON SAID FRAMEWORK DISPOSED ABOVE SAID RECEPTACLE, SAID DRUM ASSEMBLY COMPRISING A YOKE-SHAPED FRAME INCLUDING A BIGHT PORTION AND A PAIR OF SIDE MEMBERS, A SHAFT ROTATABLY JOURNALED IN SAID BIGHT PORTION AND EXTENDING SUBSTANTIALLY CENTRALLY OF AND PARALLEL TO SAID SIDE MEMBERS, A CYLINDRICAL PERFORATED DRUM HAVING A PERFORATED BASE AND AN OPEN END MOUNTED ON SAID SHAFT AT SAID BASE THEREOF, AN IMPERFORATE CYCLINDRICAL SHROUD ON SAID FRAME ENCIRCLING THE PERIPHERY OF SAID DRUM FORMING AN ANNULAR SPACE THEREBETWEEN, A MOTOR ON SAID FRAME, MEANS DRIVINGLY CONNECTING SAID MOTOR AND SAID SHAFT FOR EFFECTING ROTATION OF SAID DRUM ABOUT ITS LONGITUDINAL AXIS, A TRUNNION ON EACH OF SAID SIDE MEMBERS PROJECTING LATERALLY THEREOF AND DISPOSED IN AXIAL ALIGNMENT WITH EACH OTHER, BEARING MEANS ON SAID FRAMEWORK FOR ROTATABLY SUPPORTING SAID TRUNNIONS ENABLING PIVOTABLE TILTING MOVEMENT OF SAID DRUM TO AND FROM AN UPWARDLY INCLINED DRYING POSITION AND A DOWNWARDLY INCLINED UNLOADING POSITION, AND CRANK MEANS ON ONE OF SAID TRUNNIONS FOR EFFECTING TILTING MOVEMENT OF SAID DRUM ASSEMBLY, A BLOWER ON SAID FRAMEWORK, A DUCT EXTENDING BETWEEN SAID BLOWER AND SAID RECEPTACLE AND DISPOSED IN COMMUNICATION WITH THE INTERIOR THEREOF, A HEATER IN SAID DUCT FOR HEATING THE AIR THEREIN TO A PRESELECTED ELEVATED TEMPERATURE, A CONDUIT DISPOSED IN COMMUNICATION WITH SAID BLOWER INCLUDING A HINGEDLY MOUNTED NOZZLE THEREON MOVABLE TO AND FROM AN OPERATIVE POSITION WHEREIN ITS OUTLET END IS DISPOSED IN THE INTERIOR OF SAID DRUM WHEN IN SAID DRYING POSITION EFFECTING MOVEMENT OF AIR THROUGH THE INTERIOR OF SAID DRUM OUT THROUGH THE PERFORATIONS THERETHROUGH AND INTO SAID ANNULAR SPACE THEREAROUND TO AN INOPERATIVE POSITION ANGULARLY SPACED FROM SAID OPERATIVE POSITION AND IN CLEARANCE RELATIONSHIP FROM SAID DRUM ENABLING UNOBSTRUCTED PIVOTABLE TILTING MOVEMENT THEREOF.

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