US1982715A - Traveling agitator and the like - Google Patents

Description

. 4, 1934. A. L. WHITESIDE TRAVELING AGITATOR AND THE LIKE Fiied Jan. 29, 1932 6 Sheets-Sheet 1 BY INVEIE'QR%E- F i I I l l I l l l ATTORNEY Dec. 4, 1934.

A. L. WHITESIDE TRAVELING AGITATOR AND THE LIKE Filed Jan. 29, 1932 6 Sheets-Sheet 2 f 3/ w we 26 3 27 INVEN O 4 ATTORNEY Dec. 4, 1934. A. WHITESIDE TRAVELING AGITATOR AND THE LIKE Filed Jan. 29, 1932 6 Sheets-Sheet 3 Dec. 4, 1934.

A. L. WHITESIDE TRAVELING AGITATOR AND ,THE LIKE 6 Sheets-Sheet 4 Filed Jan. 29, 1932 4.; ATTIDRNEY Dec. 4, 1934. A. L. WHITESIDE TRAVELING AGITATOR AND THE LIKE Filed Jan. 29, 1932 6 Sheets-Sheet 5 Dec. 4, 1934. A. L. WHITESIDE TRAVELING AGITATOR AND THE LIKE Filed Jan. 29, 1952 I e Sheets-Sheet 6 3 #J mw m N I 5% i m H MU H wf WU J N% N \w Q MS Q Q w I E km 16% .b H N N m M y Y .III ILL @m www 3 Q3 I NW 9% ll \n Patented Dec. 4, 1934 UNITED STATES PATENT- OFFICE Application January 29, 1932, Serial No. 589,568 7 8 Claims. (Cl. 259-102) This invention relates toagitators for treating liquid suspensions,-such as paper pulp, cement slurries, clays, sewage and the like and more particularly to a traveling agitator which is mounted I 5 for movement across a tank containing said suspensions and is adapted for uniform treatment of the various portions thereof. Still more particularly the invention relates to an improved driving mechanism for an agitator of the above type.

Among the-objects of the present invention are; to provide a light-weight agitating device-which occupies a minimum amount of space and which may be operated by a source of power located outside of thetank of material being treated; to provide an agitator which is adjustable as to speed of travel andas to rate and direction of liquid flow; toprovide an agitator which may be readily installed and serviced without discharging the tank; to provide an improved driving means whereby positive operation is obtained with minimumpower requirements; and to provide an improved, compact and convenient device of the above type. i l r In a preferred form of the invention a propeller is mounted on a vertical shaft and suspended from a traveling carriage in a tank of liquid which it isdesired to agitate. The carriage is mounted on'a track which extends'across the tank in such manner that the carriage is capable of traveling D to and fro thereover. For driving the above device a flexible drive; such as a rope, belt-chain or cable is employed which extends across the top of the tank and cooperates with a plurality of operating sheaves mounted on the carriage. 'The flexible drive may be operated by a suitable source of power, such as an electric motor, which may be mountedoutside of the tank. A clutch mecha-; ni'sm is employed and is automatically operated when the carriage approaches the end of its travel to alternately interconnect pairs 'of said sheaves; Interconnection of certain pairs of sheaves causes movement of the carriage in one direction and in-' terconnection of other pairs of sheaves causes r movement of the carriage in the reverse direction. The propeller shaft is positively geared to one sheave shaft to provide constant uni-directional agitation during carriage travel and reversal.

The invention will be better understood and 50 further features and advantages thereof will be apparent' from the following description which discloses a preferred embodiment thereof taken in connection with the accompanying drawings in which:v

Fig. 1 a diagrammaticview of the connection of the operating sheaves to the flexible driving means;

Fig. 2 is a plan view of the device; I

Fig. 3 is a vertical section taken on the line 3-3 ofFig.2; I 1

Fig. 4-is a vertical section taken-on the line 4- -4 of Fig.3;

Fig. 5 is an end elevation of the tank and driving means;

Fig. 6 is a horizontal section taken on the line 6-6 of Fig.3; q 7

Fig. '7 is a vertical section taken on the line '7-7 of Fig. 6; I

Fig. 8is a vertical section taken on the line 8-8 of Fig. 6; i I

Fig.9 is a vertical'section taken on the line 9-9 of Fig. 6;

Fig. 10 is avertical section taken on the line- 10-10 of Fig. 6; and

Fig. 11 is a detail of the clutch operating mechanism. v r

In the various figures of the drawings like parts have been designated bylikereference characters. In the following description and in the claims various details are identified by spe-, cific meansfor convenience but they are intended to be as generic in their application as the art will permit.

Referring to the drawings more in detail, the invention is shown as applied to a tank 10 having end walls 11, side walls 12 and a bottom 13 which is adapted to contain a material, such as paper pulp, cement slurry, clay filler, sewage, etc., which is to be agitated. A plurality of channel beams 14, (Figs. 3 and 4) are carried in end walls 11 and may be attached to floor beams 15, or floor 16 in any convenient manner. Said floor is provided with a manhole 1'7 of sufficient size to receive the agitating apparatus to be described and to permit the same to be servicedor to be bodily removed from the tank.

The agitating device consists of a carriage formed by transverse frame members 20 and longitudinal framemembers 21 which are joined to form a substantially rectangular supporting frame. Said frame is hung from guide wheels 22 which are supported in-bearing members 23 carried by uprights 24. Said uprights 24 may be attached to said frame-in any convenient manner. A housing 26, adapted to contain the driving mechanism to be described, is formed having suitable dimensions to rest within frame members 20 and 21 and carries lugs 27 by which it is supported on said frame members. .Said' housing may be attachedto frame members 20 and 21 by suitable means, such as bolts 27a. It is to be noted that guide wheels 22 rest within channel beams 14 and are of such size with respect to said channel beams as to roll against the top surface thereof when an upward thrust is exerted by the propeller suificient to cause vertical lift of the entire apparatus. Said guide wheels normally roll upon the lower surface of the channel beams 14 which serve as a track to guide the carriage in its to and fro travel. It is obvious that the channel beams which support the floor may be utilized for the guide track for the carriage or additional track members may be employed as desired. In any case the track merely serves as a support and a guiding means. The housing 26 carries a pair of spaced bearing plates 30 and 31 which aremounted horizontally and provide supports for the various shafts and gears to be described. Referring to Figs. 2 and 7, the driving mechanism is shown as comprising coaxial sheaves 32 and 33 and additional sheaves 34 and 35. v

Sheave 32 is keyed to shaft 36 which issu-pported in suitable bearings 37 and '38 in bearing plates 31 and 30, respectively, and at its lower end is provided with a gear '39 which is rig-idly secured thereto. A suitable thrust bearing, such as collar 4'0; may be employed to maintain the correct operating position of said shaft.

Sheave 33 is secured to a sleeve 41 which is freely rotatable on shaft 36 and carries a gear 42 rigidly secured thereto.- Gear 42 is constantly in mesh with a cooperatinggear 45, rigidly secured 'to a shaft 46, which is mountedin suitable bearings 47 and 48 in bearing plates 31 and 30 respectively. Gear 39 meshes with :a cooperating gear 49 which is loosely mounted on shaft 46 and is free to rotate thereab'out.

Shaft 46 is extended through housing 26 and carries a propeller which may be secured thereto by any suitable means as by nut 46a and preferably is provided with blades 50 whichtare adjustable about their own axes whereby the pitch of the propeller "may be varied as desired. Suitable means, such as set screws 50a, maybe .pro-

vided for locking "blades 50 "in position. :A three blade propeller is particularly suitable inasmuch as it may be more readily removed through manhole 1'7 which maybe of slightly smaller dimensions than the over-all dimensions of the propeller. A housing 462) may be secured to housing '26 and is adapted to enclose shaft '46 and to provide a lower bearing therefor. Bracing rods 51 extending between housing 26 and collar 52 on housing 461; impart rigidity to the propeller shaft '46 and prevent undesired vibration thereof.

Referring to Figs. 2, 6 and 7, it will be noted that gear '45 meshes with a cooperating gear 5'5 which is keyed to shaft 56. Sai'd shaft 56 is mounted "in bearings 57 and 58 'and carries gear 59 in spaced relationship to gear '55. :Said gear 59 is in mesh with a gear 60 which is mounted for free rotation about shaft 61. Said gear 60 is provided with a lug 52 (Fig. 1'0) by which =driving force is applied in a manner to be described. Shaft '61 carries sheave 34 rigidly attached there to, and is supported in suitable bearings 63 and 64 in said bearing plates 31 and 30 respectively.

A collar "65 is keyed to shaft 61 and carries a yoke 66 '(Fig. 6) in which a latch member 67 is p'i-votedias by rod 68 (Figs. 6 and 10)'. Said latch member 67, in "the position shown engages 111g 62 and establishes a driving connection between shaft 61 and gear '60. It will "be in Fig. 16,

noted that the above described mechanism establishes a driving connection between sheaves 33 and 34 and that latch member 67 forms a clutch for selectively interrupting the driving connection and permitting sheaves 33 and 34 to rotate as idlers.

Referring to Figs. 6 and 8, it will be noted that a driving connection is established between sheaves 32 and 35' by means'of gear 449 which rotates independently of shaft 46 and 'meshes with a gear 70 which is keyed or otherwise secured to shaft 71. Said shaft is mounted in plates 31 and 30 by means of bearings 72 and 73 respectively. Gear 70 meshes with a gear 75 which is loosely mountedon shaft 76. Said shaft 76 carries sheave 3'5 and is supported in plates 31 and 30 by bearings 77 and 78 respectively. A

collar 79 is' rigidly secured to shaft 76 and carries a yoke 80 (Figs. 6 and 10), in which latch member 81 is pivoted as by rod 82. Said latch member -81 cooperates with "a lug 83 which is carried by gear '75 and, when in engaging position, establishes the driving connection between sheaves 32 and '35. When latch member 81 is disengaged sheaves 32 and 35 are free to rotate as idlers.

For selectively operating the clutch mechanism formed by latches 67 and 81 and lugs 62 and 83 respectively, collars 88 and '89 are provided which'rare sl-idably mounted on shaft-s 61 and "-76 respectively. Collar 881s provided with a pair of flanges-90 and-9'1 which cooperate with arm 92 formed on latch member 67 tocontrol the position of said latch member. Collar '89 is provided with a similar pair of flanges 95 and-96 which cooperate with arm 97 formed on latch member 81 "for controlling the position thereof.

For operating collars 88 and '89 a lever 100 is provided which iscarr-ie'd by rod 110. Said rod is pivoted in a bracket 101 which is supported by bearing plate 31 in any convenient'manner. Said lever 100 carries at one end a member 102 which cooperates with flanges 90 and 1'04 formed on collar 88 for controlling the position of said-collar. At its "other end lever 100 carries :a'rnember 105 which cooperates with flanges .95 and 106 .of colfar 89. It will be noted that with the lever :in the position shown in Fig. 10 flatch 67 is :brought into engagement with lug 62 for establishing fa. driving connection between sheaves .33 and 34131111 latch 81 is raised out-of engagement with lug 83 wherebysheaves 32 and :35 :aredisconnected from each other and-are free-to operate as'idlersheaves.

With lever 100 in the opposite position the connections will be reversed whereby a "driving nonnection is Iestablishedbetween sheaves '32 and 35 and sheaves -33and .34 are permitted 'to operate as idler sheaves. With the lever in a-central pcsition bo'th latches "are disengaged from their respective lugs and no driving connection exists between either sheaves 3-2 and :35 or 33 and -34,-.-al1 of said sheaves being free to revolve as independent idlers.

Rod 110 .is provided with a downwardly extendingsection .111 which is pivoted to rod 112 (-Figs. @6, 9 and 1.0) Rod 112 is pivotedto a :bell

crank lever 11 3 which is in turn connected by a rod 114 to lever 115. Lever .115 is .provided with a hub member 116v which is mounted .for -pivotal any convenient device, such as forked member 111a which is secured to the housing and, when 'in engaging position, centers and locks said lever.

The carriage is then free to move along the tank and may be manually positioned, for example, under the manhole 17 or may be manually operated in case of failure of the driving mechanism.

A segmental gear 126 is mounted on rod 117 and cooperates with a rack 127. Spring 128 is connected to gear 126 and is anchored to a suitable post 130 in bearing plate 30. Gear 126 carries a pair of pins 126a which extend outwardly therefrom and engage lever 115. Gear 126, however, is free to move independently of said lever within the limits defined by the distance between pins 126a.

Spring 128 is adapted normally to hold gear 126 in either of its extreme positions without interfering with free movement of said gear in response to movement of rack 127. When said gear has moved a sufficient distance to cause one of said pins 126a to contact with lever 115 and to move said lever past its central position, spring 120 will cause lever 115 to move rapidly to its other extreme position. The lost motion provided by pins 126a andlever 115 accordingly permits a quick action of lever115 and the operating mechanism associated therewith whereby the clutch mechanism is quickly thrown from one position to the other when movement of rack 127 takes place. l

Referring to Fig. 9 it is noted that rack 127 is carried by rod 135 which is slidably mounted in bearings 136 in housing 26. Said rod extends beyond said housing on both ends thereof and engages stop members 137 and 138 which are mounted on the two ends 11 of tank 10. The arrangement is such that when the carriage approaches either end of tank 10, rod 135 engages the corresponding stop member and causes movement of rack 127, thereby throwing lever 117 and, through the linkage above described, reversing the position of latch members 67 and 81.

The driving means for the above described mechanism comprises a flexible driving member 140, such as a belt, chain, rope or cable which for ease of description will be hereinafter referred to as a rope passing around sheaves 32, 33, 34 and 35 in a manner to be presently described. At one end of tank 10 said rope is passed around idler sheave 141 which is mounted on end wall 11 in any convenient manner. Said rope extends across the top of tank 10 and passes around idler sheaves 142 and 143 (Figs. 3 and 5), and thence around driving sheave 145. Said driving sheave and an intermediate sheave 146 which is rigidly secured thereto are mounted on a sleeve 146a to revolve freely on shaft 147 in arms 148 which are pivotally supported from a stationary supporting member 149. A tensfiming means,'such as weight 150 may be hung as by yoke 151, from rod 147 and is adapted to maintain proper tension on the driving rope 140.

Sheave 146 is driven by belt 152 from sheave 153. Said sheave 153 is rigidly secured to a sheave 154 which is mounted for rotation in supporting.

tain the proper tension on rope 140 without altering the tension of belts 152 and 158 and consequently without changing the driving force which is transmitted from motor 157 to said sheave 145.

Referring to Figs. 2 and 3, it will be noted that l around the various sheaves above mentioned.

One arm 148 and yoke 151 may be readily removable in order to permit saidendless rope to be applied to sheave 145. r

Inasmuch as the rope 140 passes from an upper sheave 32, around to idler sheave 141, to a lower sheave 33, it is obvious that said sheave 141 may be mounted in an inclined position or may be formed with a wide groove to permit the neces sary lateral movement of the rope to take place. A suitable cover 165 may be mounted over the entire operating mechanism and may rest upon housing 26 and be secured thereto in any convenient manner. 'Slots 166 may be formed in cover 165 to permitthe same to pass over rope 140. Said cover is adapted to be lowered through manhole 17 and it is to be noted that the operating mechanism including the various sheaves are accessible through said manhole and the rope may be threaded about said sheaves while the apparatus' is located under the manhole in the position shown in Fig. 3. The apparatus, however, is entirely carried within the tank and does not extend above the floor or require space, other than that within the tank itself. Furthermore, the apparatus may be constructed of comparatively light material inasmuch as it is driven by rope 140 in the manner to be pointed out and does not depend upon the traction of wheels 22 for the driving force. Said wheels in the present invention merely serve as guide means and contact with either the lower or upper surfaces of channels 14 depending upon the direction and amount of thrust exerted by the propeller.

In the above described apparatus sheaves 32 and35 and sheaves 33 and 34 are shown as of different diameters and the driving connection between the pairs of gears in such that when either of said pairs is coupledv by the above described clutch mechanism, a one to one gear ratio is established and the gears drive at identical speeds. For this reason it will be noted that the two sheaves of the coupled pairs, of unequal diameters, for example sheaves 32 and 35, travel at different peripheral speeds. This feature is made use of in a manner to be described for causing the lateral movement of the carriage. It will be obvious, however, that the different peripheral speeds of the coupled sheaves can be obtained by various other means, as for example by construct-' ing the sheaves of the same diameter and so constructing the gears that they are caused to rotate at different angular speeds.

When a moving rope passes over a sheave that is free to move laterally and the sheave is forced to revolve at a peripheral speed different from that of the rope the sheave will rotate and in addi-' tion, will move laterally in the direction of travel of the rope or in the reverse direction depending upon whether the peripheral speed of the sheave is less or greater, respectively than the speed of;

In either case the speed of travel of the rope. lateral'movement of the sheave will be equal to the difference between :its peripheral speed and the speed of travel of the rope.

Referring to the diagram of Fig. 1, it may be .assumed that sheaves 33 and 34. are coupled for the same angular speed of rotation and sheaves 132 and are free to rotate as idlers. Assuming, by way of example, that the ratio of the diameter of sheaves 33 and 34 is such that sheave 33 has :a peripheral speed of 1300 feet per minuteand sheave 34 has a peripheral speed of 1100 feet per minute and that rope 140 has a forward speed of 1200 feetper minute, it will be noted that sheave 33, which has a speed greater than that of the rope will tend to move in the direction opposite to that of the rope'or to the left as viewed in Fig. 1. Sheave 34, having a speed less than that of rope 140, will tend to move in the direction of movement of the rope or to the left as shown in Fig. l. The rate of lateral movement of both of said sheaveswill be 100 feet per minute in the example above given and the carriage will accordingly be caused to move laterally across tank 10 at that speed.

When the clutch mechanism is operated by rod 135engaging abutment 138 at the left hand end of the tank, sheaves 33 and 34 are disconnected and are permitted to operate as idlers and sheaves 32 and 35 are coupled. Said sheaves 32 and 35 both tend to move to the right as shown in Fig. 1 for reasons similar to those outlined above Reverse movement of the carriage accordingly takes place which will, continue until rod 135 contacts with abutment 137 and; operates the clutch mechanism. To 7 and fro movement of said carriage accordingly takes place so long as power is applied to rope 140 or until lever 111 is locked in neutral position. The propeller, which is operated by shaft 46 to which power is continuously applied from sheave 33, is continuously operated regardless of the move.- ment of the carriage.

Since the power required for operating the propeller is greatly in excess of that required for causing lateral movement of the carriage, the shock on the driving motor occasioned by reversal of the movement of the carriage is negligible. Furthermore, by reason of the substantially constant power requirements and the elimina-.v tion of the necessity of a heavy starting torque, a motor of comparatively small power may be employed.

In a preferred form of the invention a fume proof transmission rope is employed which may be readily removed and replaced in the manner above described and which may be readily disconnected from the driving sheaves when it is desired to remove the apparatus from the tank. Furthermore, by locating the source of power at a point outside of the tank, the space requirements are minimized and also the weight of the carriage is reduced and the necessity for shielding the motor from fumes is avoided. The entire device may be enclosed. in a substantially splash proof cover and a completely sealed housing and both may be formed of fume proof material or the unit maybe protected by a metal coating or paint as may be required. The term sheave has been used herein for convenience but it is intended to include various types of. rotating members capable of cooperating with the belt, chain, cable, rope or other type of flexible drive.

The device may be operated in a place having low head room inasmuch as a carriage of minimum thickness is employed and the gear box, if

.desired, can be sealed and actually run within the wires, exposed. wheel drives, control switches and all :moving parts liable to be affected by vapors or fumes have been eliminated or removed to a location without the "tank.

be detached from the carriage frame "when .neces sary.

A feature of the invention resides in thefact that-maintenance and servicing may be accomplished without emptying the tank and that replacement units can be installed with a minimum of interruption and delay.

The continuous propeller action produces 1 a flow of liquid in one direction, that is, a vertical flow either upwardly or downwardly. The propeller blades, being adjustable, can be set for any desired velocity of flow, either upwardly or downwardly. "This feature is important in certain instances, as for example in treating cement slurry which may require an upward flow to carry heavy precipitating particles into the upper strata and in treating other mixtures, such as pulps which may require a downward flow of liquid'to bring the floating materials or light density liquids-into thorough intermixture at the bottom.

By reason of the elimination of the shock load which wouldotherwise occur on carriage reversal, arsmall motor without :high torque characteristics and without electrical controls, other than a starting switch, may be employed.

The velocity of flow through the propeller, and the "frequency of passing the propeller through any area may both be independently adjusted to suit the consistency and precipitating characteristic of the mixture or solution to be agitated.

The speed of travel of the carriage may be varied by changing the gear ratios or the sheave diameters or by changing the motor speed. The velocity and direction of flow of liquid may be controlled by varying the angle of the propeller blades or by changing the motor speed or the diameter of sheave '33 or gear ratio of the gear train interconnecting shaft 46 and sheave 33.

In the above description a single propeller has been'shown by way of example. It is evident however that a plurality of propellers, either on the same or different shafts may be employed, or a plurality of traveling carriages may be mounted over a single tank on the same or separate tracks and driven by one or a plurality of ropes.

Although a specific embodiment of the invention has been described for purposes of illustration, various modifications and alterations will be apparent to a person skilled .in the art .to Which it appertains and the invention is only to be limited in accordance with the scope of the following claims.

What I claim is:

1. An agitator comprising a carriage having a rotatable member, a flexible driving means peripherally engaging said member, means cooperating with said driving means for causing said member to rotate at a peripheral speed differing from the linear speed of said driving means whereall) by lateral movement of said member takes place, pulleys mounted for rotation about flxed axes located beyond the opposite ends of the path of lateral movement of said member, said flexible driving means engaging said pulleys, an agitating device mounted on said carriage, and means whereby rotation of said member operates said agitating device.

2. In combination, a carriage mounted for lateral movement, said carriage having a plurality of rotatable members thereon, means for coupling certain of said members and causing the same to operate at different peripheral speeds, a flexible driving means peripherally engaging said members and traveling at a linear speed intermediate the peripheral speeds of said members whereby lateral movement of said carriage is thereby effected, and pulleys mounted for rotation about fixed axes beyond the opposite ends of the path of movement of said carriage, said flexible driving means engaging said pulleys.

3. In combination with a carriage, a plurality of rotatable members mounted thereon, a flexible driving means peripherally engaging said members, selective means for causing certain of said members to rotate at a peripheral speed different from the linear speed of said driving means, utilizing the speed diflerential to produce lateral movemnt of said carriage in one direction and selective means for causing others of said members to rotate at other difierential speeds with respect to the linear speed of said driving member to produce movement of said carriage in the opposite direction.

4. A carriage having two pairs of rotatable members, each of said pairs having means for establishing a driving connection therebetween, such that the members of each pair rotate at different peripheral speeds, a flexible driving means peripherally engaging said members and means for alternately interconnecting the members of each pair and causing the members of the other pair to operate as idlers, the relationship between the linear speed of travel of said driving means and the peripheral speed of the said members being such that lateral movement of said carriage is effected.

5. An agitating device for a tank comprising a carriage mounted for movement across said tank, a propeller carried thereby and extending within said tank, said carriage having a plurality of rotatable members thereon mechanically arranged in pairs, a clutch mechanism for selectively interconnecting the members of each pair, a flexible driving member peripherally engaging said members, the members of each pair being rotated at peripheral speeds differing from the linear speed of travel of said driving member when said members are mechanically interconnected and means mounted on said carriage and operated when said carriage approaches the end of its travel for controlling said clutches and thereby causing reversal of movement of said carriage;

6. In combination with a tank, an agitating device comprising a carriage, means for mounting said carriage for movement across said tank, a propeller carried by said carriage and extending within said tank, a flexible driving member extending parallel to the line of movement of said carriage, rotatable members carried by said carriage and peripherally engaging said driving member for obtaining driving force therefrom, clutch mechanism for. selectively controlling the direction of said driving force and operating means for said clutch mechanism comprising a slidable rod extending longitudinally of said carriage, stop members mounted at opposite ends of said tank in a position to engage said rod, the 1 movement of said rod produced when said rod engages one of said stop members serving to operate said clutch and to thereby cause reversal of movement of said carriage.

'7. In combination with a traveling carriage, a. plurality of rotatable members mounted thereon, certain of said members having a given diameter and others of said members having a different diameter, means for selectively coupling in pairs the members of different diameters for movement at the same angular speed, a flexible driving member peripherally engaging said rotatable members and traveling at a linear speed different from the peripheral speed of said coupled members whereby said coupled members are caused to rotate and to travel in a path parallel to the line of movement of said driving member.

8. An agitator comprising a carriage mounted for lateral travel, a propeller carried thereby, rotatable means mounted on said carriage for causing rotary movement of said propeller, a sta tionary power source including-a driving pulley mounted at a point beyond one end of the path of travel of said carriage, an idler pulley mounted beyond the other end of said path of travel, a flexible driving member engaging said driving pulley, said rotatable'means and said idler pulley, and means cooperating with said driving means for causing said rotatable means to rotate at a peripheral speed differing from the linearspeed of said driving means whereby lateral movement or said rotatable means takes place.

ARTHUR L. WHITESIDE.

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