US2010295A - Conveying and supporting mechanism - Google Patents

Description

Aug. 6, 193.5. H. A. DR'l-:IFFEIAN 2,010,295

CONVEYING AND SUPPORTING MECHANISM v Filed Deo. 18, 1933 4 Sheets-Sheet l Aug 6, 1935. H. A. DRl-:FFEINv v I 2,010,295

CONVEYING AND SUPPORTING MECHAI SM Filed Dec. 18, 1953 4 Sheets-Sheet 2 w Kx' 9' jefqgeffea l JM Aug. s, 1935. H. A. DREFFEIN 2,010,295

CONVEYING AND SUPPORTING MECHANISM Filed 13120.18, 1953 N4 sheets-sheet 5 @9d ya@ 7? l//z/l/ Aug. e, 1935.

H.A. DREFFEIN CONVEYING AND SPPORTING-MECHANISM Filed Deo. 18, 1933 y 4 Sheets-Sheet 4 XNNKWMU NUNN DNN QNN Patented Aug. 6, 1935 PATENT'. OFFICE CONVEYING AND SUPPORTING Y MECHANISM Henry A. Dreffein, Chicago, Ill.

Application December 18, 1933, Serial No. 702,866

12 Claims.

This invention relates to conveying and supporting mechanism, primarily it contemplates in association with a pack heating or other furnace, for example, reciprocable conveying members, such as bars, with which intermittently actuated lifting and supporting members coact.

In the form illustrated, the movement of the conveyor members is such that a portion' sufficient to receive a charge of packs or other material will project from one end of the furnace or the other at each limit of travel, so that in one position charging is possible, and in the other position the heated pack or other material may be removed for subsequent treatment. In the movement from this discharging position back to charging position, the lifting and supporting members function to raise and support the other packs above the conveying means until the return movement is completed, when the material is again deposited upon the conveying means.

Coacting with the above described apparatus, is driving apparatus by which operative movement is transmitted to the conveying means and to the supporting means. This includes a tension means together With mechanism whereby at least a large portion of the tension acting upon the driving means for the conveyor is relieved, pending the initiation of the return movement of the conveyor members.

My invention also includes other details and subcombinations which are more fully described below and shown in the accompanying drawings,

in which Fig. l is a vertical section through a furnace illustrating an embodiment of my invention applied thereto;

2 is a horizontal section of the same;

Fig. 3 is an enlarged detail of a portion of the conveying and supporting mechanism; 4

Fig. 4 is a plan viewof a portion of one of the conveyor members, parts being broken away for clearness;

Fig. 5 is an enlarged sectional detail taken along the line 5-5 of Fig. 2; i

Fig. 6 is a vertical section along the line 6-6 of Fig. 5;

Fig. 7 is a vertical section drawn to an enlarged scale along the line 'I-l of Fig. 1;

Fig. 8 is a diagrammatic View of controlling means for the furnace illustrated and described, portions of the furnace, conveyor and accessory apparatus being included for convenience; and

Fig. 9 is a side elevation of a detail of one of the limit switches and actuating means. i

Like numerals refer to like elements `throughout the drawings. Y

It! designates generally a pack heating furnace having a refractory top Illa and bottom IUb, to-

gether with the usual side Walls Ille, Ind. I have illustrated a combustion and heating chamber Ie located on one side of the furnace (see Fig. 2) the same forming no separate part of my present invention. A suitable burner 9 is provided at one f end of the combustion chamber IIIe, being illustrated as adapted for the use of gaseous fuel, although obviously any suitable fuel supply and burning means may be utilized.

The ends of the furnace I0 are provided with the openings lili, leg, respectively, the former being the discharge opening and the latter the charging opening.

At each end of the furnace proper is provided a vertically movable door II mounted to lie adjacent the upper surface of the conveyor, described below, when in closing position. Any suitable type of door operating means may be utilized,v but I have illustrated an operatively satisfactory form in Fig. l, for example, Where the door IIsuitably guided for its vertical movement is connected through a flexible chain or cable IIa to a segmental pulley IIb in turn mounted upon a cross shaft Ile. Extending outwardly from the cross Vshaft is the arm IId carrying a counter-weight I Ie. -An air cylinder I I f is provided with suitable inlet andV outlet pipe Ilg. Extending vertically upward from a piston I I h (see Fig. 3) is a piston rod l Iz' pivotally attached to the arm I Id. When air is admitted to the cylinder II f the arm I Id is depressed and the chain II a or flexible driving member is partially wound upon the rotating segmental pulley IIb to raise the door, as will be obvious. Cut-01T of the air supply to the cylinder I I f will permit the piston and associated apparatus to return to door closing position. The same apparatus is illustrated as applied to the door at the charging end of the furnace, although this door may be omitted if so desired.

. Upon the iloor Ib of the furnace are supporting blocks I2 extending transversely thereof as illustrated in Fig. 2, for example. Mounted upon the supporting blocks i2 and secured thereto are the bearing brackets I3, in which are journaled rollers I4, as illustrated in Figs. 3 and 7, for example. These rollers Ifl arepreferably flanged at the edges, as indicated by numeral Illa, for a purpose hereinafter described. Conveyor members or bars generally indicated by numeral I5 are supported upon the flanged rollers I4, there being" a plurality of these conveyor members mounted in parallel and spaced relation. Each of these conveyor members is preferably formed of articulated links lo, the links being illustrated as of Lsection, each link it having an extended flat tongue lea at one end slightly offset to engage between the top and bottom anges of the adjacent bar to which it is pivotally connected by pin il (see Fig. 3) In this manner an articn ulated conveyor member is formed of substantially straight line construction. The lower ange of the conveyor link l il moves between the anges ifi of the rolls and substantial lateral movement is thereby prevented, as will be obvious.

Preferably I construct the links lf3 and locate the rolls it in such manner that when the mechanism is in the position illustrated in Fig. 2, for

example, i. e., what I term charging position, or in its other rest position, i. e., discharging position, each link will be directly supported by one of the rollers at a point nearer one of its ends than the other. I calculate these points as about 18% of the total length from the nearer end. When properly supported in this manner, a vmaximum of support and a minimum of deiection due to superimposed loads will result, as will be apparent to those skilled in the art upon calculation of moments and stresses. The end of each conveyor member i5 at the discharge end of the furnace has attached one end of a chain 28, which moves over and is engaged by the sprocket 2l (see Fig. l), thereafter passing partially around an idler 22. The opposite end of this chain 2@ is attached to a cable 23, the other end of which it attached to the opposite end of the correspondingconveyor member l5. Each of these cables 23 passes partially around an idler and thence partially around a tensioning roller 26, and thereafter partially around a second idler roller 2l.

A driving motor is provided, generally illusn trated by numeral 2S, Which through a speed reducing gearing diagrammatically illustrated and designated by numeral drives a shaft 3l. Upon thisA shaft Si are mounted for rotation therewith, the sprockets 2l. Control means hereafter described are provided for the motor 29. When the same is actuated to rotate the sprockets 2i the conveyor members l 5 are moved from charging position, illustrated in Fig. l, to discharging position or toward the left. lIhis movement follows movement of the doors to opening position and positions a heated metal pack or other object for removal or transfer to other treatment apparatus by the operator, and while this operation is being carried on the doors may be permitted to close. Subsequently, through control means. also described below. a reversal of the conveying means is effected, as will be more fully described.

Prior to the'inovement to discharging position when in normal use, a fresh pack, for example, is charged upon the end or the conveying apparatus which prot-rudes from the charging opening, consequently means rnust be provided to prevent return movement or the load upon the entire length of the conveyor during its return movement, as otherwise there would be no provision for further charging and no relative advance of the heated packs toward discharging position. Therefore, I provide a lifting and supporting apparatus which raises the packs, or other material in the furnace, above the conveying apparatus, and supports the same in such position during return movement of said apparatus. To accomplish this I provide supporting bars, generally indicated by numeral 35, each formed of a plurality of links 3S loosely connected to permit expansion and coni traction, and generally similar in construction and arrangement to the links lli of the conveyor bars l5. rIhese supporting bars are located in the spaces between the conveyor bars (see Fig. 7), and are mounted upon blocks 3l. which in turn are carried upon cross beams 38. These cross beams are located between the transverse supporting blocks i 2, as illustrated in Figs. l and 2. Supporting rods 3:9 shown as two in number, although the number be varied as desired, extend from beneath the beams 3S through suitable apertures in the hearth or iioor of the furnace, and through guide plates lli, forming the ends of guide cylinders, the bodies of said cylinders being enlarged to provide ample clearance around the rods 3s. At their lower ends, these rods are supported upon longitudinal beams dlS. The bars 35. blocks 3i and beams are so diinensioned that when the longitu nal beams (as will be more fully explained) are lured a sulicient amount, the bars 35 will project above the horizontal plane of the upper Webs of the conveyor bars l5, and vvill pick up and support the packs, or other loa-d. formerly resting upon Said conveyor bars. Secured to the substructure of the furnace are short beams on which are mounted bearings a, in which bearings are journaled shafts Lita carrying bell cranks One extremity :lf-5b of each of these bell cranks i5 is pivotally secured to a rod lll, which in turn is secured to a cross-beam engaging the longitudinal beams A connecting rod 563 extends between and is pivotally connected to the ends of bell cranks Q6 providing parallel motion for the respective bell cranks i6 and beams lit. At one end of the connecting rod 56 is pivotally attached a radius rod al, the point of pivotal engagement Sia being illustrated asinterrnediate the ends of the radius. At its upper end and at 59h, the radius rod is suitably pivoted at a iixed point substantially in the horizontal plane of the pivotal points of the bell cranks 6, as illustrated in Fig. l. At its lower end at Eile, the radius rod is pivotally attached to a connecting rod 55, which in turn is pivotally attached at a to the crank 55a or a motor 5t. I have illustrated this motor as being associated with a suitable speed reducing gearn ing. It will be apparent that When the motor is actuated to rotate the crank 5ta in the direction indicated by the arrow in Fig. 8, the beams will be lifted during the first half revolution of the crank. Suitable control mechanism is provided for control of the actuation of this 1iftH ing motor and associated apparatus, and he same will be more fully described hereinafter. 1 the tensioning of each cable 23 and driving chain El), I provide a pair of weights, the one being relatively light and the other, 65, being relatively heavy. The former Weight is attached to a yoke fic, which in turn is supported upon and rotatable to the shaft of a corresponding pulley 3S as illustrated in Fig. 6. Depending from each of the Weights Sil, is a rod Ma, having a nut tlb or head thereon. This rod Sii, extends through a cap upon the casing or container which -c of Weight S5. I have illustrated this being arranged for addition to or subtraction therefrom and variation in such way as desired.

Each of the Weights is provided with a pair of upwardly projecting straps i9, which are merged at the top to form, in eifect, a bail einbracing and spaced from the smaller Weight til Aand slotted at G9a to permit protrusion of the ends of the corresponding shaft of pulley 2S. At the upper end is provided a threaded stem 69h, which extends through an aperture 'lila and the arm 10b of a bell crank 16. A sleeve tc is provided around a threaded portion of stem E919 to protect it from abrasion by the bell crank arm 10b. Threaded upon the stem 91) is an adjusting nut 69d between which and the bell crank 7! is provided a cushioning spring 12, as illustrated in Fig. 5. Each o these bell cranks is pivoted upon a cross shaft 14 suitably supported at its ends. A connecting rod 'l5 is provided for each of the bell cranks lil, being `in pivotal engagement with the lower end of arms 'Hic thereof. A slot 15a is provided for this connection to insure lost motion during a portion of the reciprocation of the rods l5, which at their other ends are pivotally connected to the cross rod 59 which in turn engages rods 50 and 5l.

It will be apparent that when the rods l5 are in the position illustrated in Fig. l, the bell cranks 'l0 will have been actuated to lift the bars 63 and thereby to have lifted the weights S5 from dependence upon the rods 64a, and weights 64, suiiicient clearness being provided beneath the cap 65a to permit this movement as illustrated in Fig. 6.

When the crank arm 56a has moved one half revolution in the direction of the arrow in Fig. 8, the weights 65 will be permitted to drop until they engage the nuts 64b, after which further movecombined weight of weights E4 and 55 is exerted upon the corresponding yokes 84e and in turn upon the cables 23. When, however. the crank 5ta is in the position illustrated in Fig. l, the weight @5 is lifted and the only tension upon cables 23 is that due to weight 64.

The purpose of the apparatus just described is to relieve the conveyor bars of the maximum tension from the cables and chains, except during movement from discharging to charging position when the drive is through the chain and cable. Otherwise, the bars are subjected only to the tension resulting from weights 64. This is highly desirable, because the bars, being under intense heat in some furnaces, at least, might be drawn out and deformed and interfere with the proper functioning of the apparatus. Also, it is obvious that the greater' the tensioning weight, the more power will be required to actuate the conveying apparatus.

In Fig. 8 I have illustrated automatic or semiautomatic control means. A two-way valve generally indicated by numeral l B0 is provided in the air line Hg. When in its normal position relief is provided for the cylinders Hf to permit the pistons I Ih to rise under the weight of the doors to the dotted line position, illustrated in Fig. 8.

For actuation oi these pistons reversely, I provide a solenoid lill, illustrated as' an extension of the valve stem, and a coil m2 forming a part of the circuit a. This circuit a is connected tothe line wires L and has included in it the normally open switch S. The switch proper is connected to a solenoid H35 having a pair of spaced contact bridges Ei, lill. A coil Hi8 coacts with the solenoid 95 and is in the circuit b. This circuit b is divided into the two branch circuits bl, b2. The former includes a pair of spaced contacts which are arranged to be bridged by the contact bridge |96 and terminates at the switch F normal,- ly open and leading to the other of the line wires L. This switch F is intended for manual operation and may be of any suitable construction, being provided to initiate the forward movement of the conveyor moving from charging position, as illustrated in Figs. l and 8, to discharging position.

.The other branch circuit b2 includes a pair of spaced contacts arranged to be bridged by contact l 91 and is in turn divided into two branches b3, be, the one leading to a double pole switch S2, spring-held in one position to close cicuit b3 which leads therefrom toa second normally closed manually operable switch A in turn connected to one of the line wires L. Manual opening of this switch A serves to arrest movement or the conveyor at any time if so desired.

A limit switch Si is provided which is normally held in open position by means of a coil spring or the like. An arm .lill is carried on the shaft ilc and provided with a pivotally attached depending rod l i loosely guided at l l la and carrying the pivoted striker Si?, which is so mounted upon the rod Hi normally to lie in striking position to pick up the arm of switch Si on opening movement of the doors, its pivotal mounting and the inclined face H2a permitting it to ride by the arin of switch SI on reverse movement. This switch Si is included in a circuit c leading from one of. the line wires L.

The motor 2S is illustrated as of three-phase construction. Line wires Li are provided'for this actuation. A three pole switch M and a similar three pole switch N are provided for control of the operation oi this motor 29. The switches M and N are normally open and are o similar construction, the switch M being intended to throw the motor Z9 into movement or rotation in one direction, and the switch N arranged for reversal. The switch M, for example', is operatively attached to the stern i i5@ oi solenoid i it which carries the spaced bridging contacts Ht and Si?. A coil HS is operatively associated with the solenoid Siti and is in circuit c. which branched to form circuit ci withspaced contacts arranged for bridging by member i553. The branch d includes a pair of spaced contacts arranged for bridging by the member ill and is joined to circuit be.

Switch N is similar' in construction and the wir-- ing arrangement is such that line wires Ll' so connected as to move the motor 2Q in one direction when the switch M is closed and to reverse it when switch N is closed, as will be obvious from the diagram to those skilled in the art.

Associated with the conveyor are the pivoted spring-extended striker members 25 and 12E, one being located adjacent each end, although other suitable means moving with or synchronized for movement with the conveyor will be suitable, il so desired, and within the purview of my invention.

The poles or blades of switch S2 are so spaced and the switch is so constructed as to be moved to the left, as viewed in Fig. 8, on movement of the conveyor to discharging position, this movement of the switch first serving to open circuit b3 and then to close a circuit e leading from one of the line wires L. Switch S2 moves sufficiently during the final move-nient of the conveyor to permit striker member 25 to move between the poles, after which the spring resisting means returns switch S2 to its normal position closing circuit b3 and opening circuit c.

A switch O similar to switch M is provided to initiate and maintain forward movement of the lifting motor 56 and similarly a reversing control switch P, similar to switch N, is provided to effect reversal of the lifting motor Circuit e is normally closed through bridging contact itil and includes the magnet i3! associated with the solenoid i3? of switch O, which in turn leads to the complementary line wire L. A branch circuit f is connected to and leads from circuit e to include the normally open spaced contacts which may be bridged for closing the circuit by the second bridging member E33, similar to member i il of switch M. This circuit f leads to and through a normally closed spring-urged switch SE and thereafter through the normally closed pole of switch S3 which is spring resisted and similar in construction to switch The circuit is further extended to join circuit b3 through arrester or stop switch A to the other line wire L.

On the reciprocable rod l5@ are provided a pair oi spaced strikers till, similar in construem tion and arrangement to strikers i 25 and l2?. 1n movement oi the rod t to the right, as viewed in Figs. l and 8, i. e., du ig the lifting movement or" motor striker ifll will pivot to ride by switch S5 without disturbing the same fis the lifting movement is completed, the striker will momentarily open circuit y by actuation of spring resisted swich` S3 and shortly thereafter will close the circut g leading from one of the line wires through the switch SS. As soon as the striker has moved between the two poles or actuated members of switch latter will spring-rotar ed to normal position, as illustrated in the drawings.

On the reverse movement of the lrv uing motor, striker irli will move out of proximity to switch S3 without disturbing the saine, and end oi the reverse movement oi the rod preached, striker lilo will mon switch S5 and cir-cuit f until striker i whereupon the spring resisted switch closed, reclosing circuit f.

Circuit g leads through the contacts normally closed by bridging member i435 of said switch N through solenoid coil tit to the other line wire. Branch di of circuit d includes the spaced contacts which are bridged by the second bridging member tilt of switch N, which is likewise carried on the stem lla of solenoid Eile. A branch circuit It also leads from circuit g to normally open manually-actuated switch- R, which in turn is connected to the other line wire.

At the charging end oi the furnace is a double pole switch Sli similar to switch S2 and lying in the path of striker iit, which is similar in construction to striker 25 but oppositely arranged. As the conveyor approaches discharging position on its return movement, the pole of switch S3, normally closing circuit bfi, is momentarily opened, breaking said circuit, while the other pole or blade is moved into position closing the circuit which Ehave designated as it, which leads from one line wire L to the control for switch P. The circuit 7c includes a pair of spaced contacts which are normally closed by bridging member i550 of switch P, and included in the circuit is the solenoid coil ibi which leads to the other line wire L. A branch fl of circuit f leads therefrom to include a pair of spaced contacts which may be bridged by the second bridging member 52 of the switch P, these contacts being carried by solenoid as in the cases of switches M and O.

When the conveyor has reached charging position striker i2@ will lie between the movable poles or blades of switch and the latter will have been returned by its spring-actuating means to normal position closing circuit bil.

In the operation oi the apparatus described, assuming that the conveyor and associated mechanisms are in the position illustrated in Fig. 1, the

operator upon temporarily closing the switch F closing the circuit b-bt, may thereafter release the switch which returns to open position. This momentary closing of this circuit excites the rnagnet ille sufficiently to lift the solenoid itil into its upper position wherein circuit hifi will be closed and maintained in closed position, which throws the' solenoid Eil-3 into circuit b-b2 and b3. This movement of the solenoid also closes switch S, closing the circuit c which results in opening of the solenoid valve loi and flow of air to the door cylinders iif which, as described before, will result in opening movement oi both doors, if two are used. AsA the left hand door is opened, switch Si is momentarily closed by striker H2 which thereafter rides by the switch permitting it to return to open position. Temporary closure of switch Si closes circuit c actuating the solenoid H5 which is lifted to close circuit at the same time breaking circuit c. Closure of circuit d throws the solenoid into circuit comprising a portion of circuit c, circuit d, circuit he, switch Si, switch circuit and normally closed switch A to the other line wire. above described movement of scienoi" l i5 has suiiced to close the three poles of the current supply switch for motor which then rotates to move the conveyor to the left, the open doors having been raised sufiiciently to clear the metal packs or other mateals on the conveyor. The last describedl circuit, serving as it does to make the circuit through magnet i E keeps the switch M closed.

As the conveyor approaches its discharging position, switch S2 is moved by striker as described before, temporarily opening circuit b3, circuit b--b2, thereby breaking the circuit of magnet ict and permitting the solenoid 95 to drop, thus opening switch S, after which the door operating pistons return under actuation from the weight of the doors to closing position. At the same time, the circuit, which includes bil, switch Se, circuit d and a portion of circuit c, is broken, thereby terminating the excitation of coil iig, permitting the solenoid M5 to drop, thus opening the forward control switch M of conveyor motor 29.

As the conveyor completes its movement to discharging position, striker will also move switch S2 to close the circuit c exciting the coil iti and closing switch C to start the lifting motor 5S. This same movement of solenoid i232 closes the circuit f through switch. S5, switch S3, circuit b3 through normally closed switch A and maintains the excitation of coil li.

The operator is now free to remove or transfer the exposed metal pack or other object during movement of the conveyor motor As rod Eil moves toward its right hand limit of travel, as viewed in Fig. l, striker itl will normally open switch S3 to open circuit f and thereby discontinue the excitation oi magnet i3! to permit dropping of the solenoid E32 and opening of switch O, which stops the movement of motor 5t.

Toward the end of the lifting movement, striker lili will not only break circuit f but momentarily closes circuit g to excite coil EM and close switch N to reverse conveyor motor il@ returning the conveyor toward and to charging position, during which movement the metal packs or other objects are maintained upon the supporting members out of contact with the conveying means. 'In other words material to be heated is retained in the` furnace while the conveyor moves baclt to charging position.

` The final movement of the striker 26 past the actuated blade or pole of switch Se temporarily closes'circuit 1c before the switch Sil is released and moved to normal position by its actuating spring. This tei Lporary closure of circuitlc excites the coil lill, closing the reversing switch P for motor in a manner which will be obvious from a description or the operation of switches N and O, the auxiliary circuit which includes j being closed to maintain excitation of coil |51.

The temporary breaking of the normally closed circuit bfi by movement of the switch Se also terminates the excitation of solenoid coil |55 and permits switch M to open due to the dropping or the solenoid i thereby shutting off conveyor motor 2).

As the lifting motor 55 completes its return movement and the rod 5t is moved back toward position. illustrated in Fig. 1 for example, striker Mil will. contact and temporarily open switch S75 thereafter riding beyond it and permitting its closure by the spring. This temporary opening of switch breaks circuit f--f and as will be apparent terminates the excitation of coil |5l, permitting the opening of the lifting motor reversing switch P, which terminates the return movement of the lifting and supporting means and deposits the material again on the surface of the conveyor.

This cycle may be repeated as many times as desired, preferably being initiated in each instance by temporary closing of switch F by the operator.

If it is desired to stop the actuation of the conveying or lifting means at any time, switch A is manually opened temporarily to serve that purpose.

The conveying means may be reversed after it has first been stopped by temporary closure of the manually operated switch R, as will be obvious.

t will be apparent that the controlling circuits and switches may be modified or redesigned to perform the same functions in substantially the same manner, and I do not wish to be restricted to the form shown and described, nor tothe specific form and embodiment of my apparatus, otherwise, except as I may be limited thereto by the appended claims properly interpreted relative to the prior art.

What I claim is:

l. In apparatus of the class described, conveying means comprising reciprocable hars movable between rest positions, said bars each being formed of a plurality of pivotally connected sections, a single supporting member for each of said sections, said supporting members being located near-- er one end of each of said sections than the other when said sections are in said rest positions.

2. In apparatus of the class described, conveying meansfcompri'sing movable bars, said barsv being located each to lie near one end ofthe section supported thereby when said bars arein either charging or discharging positions.

4. In apparatus of the ciass described, conveying means comprising bars, means to move said bars, said last named means comprising rotatable sprocket chains and flexible members, said chains and :legible members extending between and operatively secured to opposite'ends of each of said bars.

5. In apparatus 'of the class described, convey- Ying means comprising bars, means to move said bars, said last named means comprisinfr rotatable sprocket chains and flexible members, said chains and flexible members extending between and operatively secured to opposite ends of each of said bars, means to tension said actuating means, and means to reduce the tension on said actuating means in one direction of movement.

6. In apparatus of the class described, conveying means comprising a plurality of bars, a chain attached at one end to each of said bars and at the other end to a flexible member, the opposite cnd of said flexible member being operatively attached to the opposite end of said bar, a sprocket engaging said chain, and means to actuate the same in either direction to reciprocate each of said bars between charging and discharging positions.

'7. In apparatus of the class described, conveying means comprising bars, means to reciprocate the same between charging and discharging positions, said last named means including flexible driving members, a tensioning means associated with each of said flexible members, and means to reduce the tension on said flexible members in one direction of travel of said conveyor bars.

8. In apparatus of the class described, conveying means comprising bars, means to reciprocate the same between charging and discharging positions, said last named means including cxible driving members, a tensioning means associated with each of said flexible members and means to reduce the tension on said exible members in one direction of travel of said conveyor bars, said last named means comprising a relatively movable weight carried by said tensioning means, a lifting member operatively attached thereto, and meansincluding a source of power to actuate said lifting member whereby said weight can be lifted out of tensioning position.

9. In apparatus of the class describedconveying means, means to reciprocate the same between charging and discharging positions, said last named means comprising a flexible driving member, a tensioning means associated with said ilexible member and including a weight, a lifting member operatively associated with said weight, supporting members movable from inoperative position beneath the upper plane of said conveying means to and from a position lying thereabove wherein material on said conveying means will be lifted out of contact therewith, means to move said supporting members between said positions, said last named means including a member operatively connected to said weight lifting member, whereby when said supporting members are moved to supporting position said weight will be released to move to tensioning position.

l0. In apparatus of the class described, a conveyor member, means to move the same between charging and discharging positions, said last named means including a exible drive member and pulleys engaging the same, one of said pulleys being provided with a depending weight,

lifting means Comprising a link engaging said Weight, a bell crank engaging said link, and a connecting rod engaging said bell crank and means to move said connecting rod axially in either direction to effect lifting of said Weight out of depending relation from said pulley or to return the same thereto.

11. In apparatus of the class described, conveying means comprising reciprocable members, means to reciprocate the same, Weights associated with said members and exerting a force thereon,

means to render said Weights inoperative during movement of said members in one direction.

12. In apparatus of the class described, reciprocable conveying members, weights, exible members operatively interposed between said Weights and said members to transmit pull from the former to the latter, and means to render said weights inoperative during movement of said members in one direction.

HENRY A. DREFFEIN.

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