US3253700A - Mechanically operated reciprocating conveyors - Google Patents

Description

y 1966 K. M. ALLEN ETAL 3,253,700

MECHANICALLY OPERATED RECIPROCATING CDNVEYORS Filed Aug. 21, 1963 4 Sheets-Sheet l INVENTORS KENNETH M. ALLEN CHESTER H- HARPER BUCKHORN, BLORE KARQUIST & SPARKMAN ATTORNEYS y 1966 K. M. ALLEN ETAL. 3,253,700

MECHANICALLY OPERATED RECIPROCATING CONVEYORS Filed Aug. 21, 1963 4 Sheets-Sheet 2 FEED I 5 RETRACT DISTANCE FIG. 6

INVENTORS KENNETH M.AL EN CHESTER H. HARPER BUCKHORN, BLORE, KLARQUIST & SPARKMAN ATTORNEYS May 31, 1966 K. M. ALLEN ETAL 3,

MECHANICALLY OPERATED RECIPROCATING CONVEYORS Filed Aug. 21, 1963 4 Sheets-Sheet 5 FIG. IO

FEED RETRACT DISTANCE INVENTORS KENNETH M. ALLEN CHESTER H. HARPER BUCKHORN, BLORE, KLARQUIST EL SPARKMAN ATTORNEYS y 1966 K. M. ALLEN ETAL 3,253,700

MECHANIGALLY OPERATED RECIPROGATING CONVEYORS Filed Aug. 21, 1963 4 Sheets-Sheet 4 FIG. 14

KENNETH M. ALLEN CHESTER H. HARPER INVENTORS. BY

BUCKHORN, BLOHE, KLAROUIST 8 SPARKMAN ATTORNEYS United States Patent 3,253,700 MECHANICALLY OPERATED RECIIRGCATING CONVEYORS Kenneth M. Allen and Chester H. Harper, both of R0. Box 352, Newberg, Greg. Filed Aug. 21, 1963, Ser. No. 303,599 4 Claims. (Cl. 198220) This invention relates to reciprocating conveyors, and more particularly to reciprocating conveyors which provide slow starting, accelerating feed strokes ending with abrupt stops to toss materials being advanced by the conveyors.

In reciprocating conveyors which operate at comparatively low frequencies, as contrasted with vibratory conveyors which operate at high frequencies, the ideal condition during the feed stroke is to start the conveyor slowly so that static frictional engagement is maintained with the material being advanced, and thereafter constantly accelerate the feeding movement of the conveyor below the point at which the static frictional engagement is broken between the conveyor and the material and at the end of the feed stroke abruptly stop the feed stroke so that the material is thrown or tossed. There have been many attempts to achieve the tossing action in the prior art reciprocating or shaker conveyors, and the prior art structures attempting to achieve this result have been very complex, difficult to maintain and with imperfect achievement of this result.

An object of the invention is to provide a reciprocating conveyor in which a conveyor bed is advanced in a feed stroke gradually accelerating to a high speed at the end thereof together with a sudden termination of the feed stroke so that material is thrown forwardly by the conveyor bed.

Another object of the invention is to provide a reciprocating conveyor which advances material with a tossing action and which is simple, effective and durable.

A further object of the invention is to provide a reciprocating conveyor in which a conveyor bed is advanced in the feed stroke thereof very rapidly, and is brought to a stop quickly so that static frictional engagement between the conveyor bed and the material being advanced is broken.

Another object of the invention is to provide a reciprocating conveyor in which a conveyor bed is resiliently urged in one direction and is restrained by a strand which passes under a crank member which is revolved to intermittently pull the conveyor against the action of the spring.

Another object of the invention is to provide a reciprocating conveyor in which a connecting rod driven by a crank is connected at its other end to a pivotal arm and to a link connected to a reciprocating conveyor bed.

Yet another object of the invention is to provide a conveyor in which a conveyor trough is suspended by pivotal links and is driven with a back-and-forth motion to advance material therealong.

The invention provides a reciprocating conveyor which includes a reciprocable conveyor bed driven by flexible means connected thereto and to crank means together with means for guiding the flexible means to impart to the conveyor bed a feed stroke in which the conveyor bed starts slowly, accelerates to a high velocity and stops abruptly to throw material being advanced thereby. In a reciprocating conveyor forming one embodiment of the invention there is provided a reciprocable conveyor bed urged in one direction by a spring and connected to one end of a strand which passes over a guide and is fixed at its other end and is engaged by a revolved crank members. Revolution of the crank member pulls and re- 3,253,700 Patented May 31, 1966 ice leases the strand to cause, with the action of the spring, reciprocation of the conveyor.

In a reciprocating conveyor forming an alternate embodiment of the invention, a conveyor bed is driven by a connecting link driven by a crank link, the links being connected to the free end of an arm pivotal on a fixed axis. The conveyor bed can be a straight trough or a spiral and can be suspended by links to enhance feeding action thereof.

A complete understanding of the invention may be obtained from the following detailed description of reciprocating conveyors forming specific embodiments thereof, when read in conjunction with the appended drawings, in which:

FIG. 1 is a fragmentary, partially sectional, side elevation view of a reciprocating conveyor forming one embodiment of the invention;

FIG. 2 is a fragmentary, horizontal sectional view taken substantially along line 2-2 of FIG. 1;

FIG. 3 is an enlarged, fragmentary, vertical sectional view taken along line 3-3 of FIG. 2 showing parts of the drive of the reciprocating conveyor of FIG. 1 in one position;

FIG. 4 is a view similar to FIG. 3 with parts thereof shown in different positions;

FIG. 5 is a diagram of the movement of the reciprocating conveyor of FIG. 1;

FIG. 6 is a schematic view of a reciprocating conveyor forming an alternate embodiment of the invention;

FIG. 7 is a side elevation view of a reciprocating conveyor forming an alternate embodiment of the invention;

FIG. 8 is an enlarged, fragmentary, top plan view of the drive of the conveyor of FIG. 7, taken substantially along line 88 of FIG. 7;

FIG. 9 is an enlarged, fragmentary, side elevation view of the drive of the conveyor of FIG. 7;

FIG. 10 is a diagram of the movement of the reciprocating conveyor of FIG. 7;

FIG. 11 is an elevation view of a reciprocating conveyor forming an alternate embodiment of the invention;

FIG. 12 is a fragmentary, horizontal sectional view taken along line 1212 of FIG. 11;

FIG. 13 is a fragmentary, horizontal sectional view taken along line 1313 of FIG. 11; and

FIG. 14 is an enlarged, fragmentary vertical sectional view taken substantially along line 14-14 of FIG. 11.

Referring now in detail to the drawings, there is shown in FIGS. 1 to 5 a reciprocating conveyor including a reciprocating conveyor bed or trough 10 mounted by rollers 12 for horizontal reciprocation. The conveyor bed is reciprocated by a drive 16 which includes an electric motor 18 driving a belt 20 to drive a fiy wheel 22. The fly wheel 22 is keyed to a shaft 24 mounted in bearing 25 carried by vertical support plates 26 and rotates crank arm 28 also keyed to the shaft 24 clockwise as viewed in FIG. 1. The plates 26 are spaced apart by spacers 34 and are supported by a base 36. The crank arm 28 revolves sprocket 30 about the center of the shaft 24. The drive reciprocates the conveyor bed to feed matreial 32 with a throwing or tossing action toward the right, as viewed in FIG. 1. This is effected by starting the feed stroke slowly, accelerating to a high velocity and stopping the conveyor bed 10 sharply at the end of the feeding stroke of the conveyor bed to break static frictional engagement between the material and the conveyor bed. The drive 16 then retracts the conveyor bed through a retraction stroke preparatory to another feed or advance stroke.

The sprocket 30, which is carried by the crank arm 28 at the outer end thereof, is revolved by the crank arm 28 with extreme positions shown in FIGS. 3 and 4, the

position of the crank arm 28 shown in FIG. 3 corresponding closely to the extreme retracted position of the conveyor bed and that shown in FIG. 4 corresponding to the extreme forward or advanced position of the conveyor bed 10. The sprocket 30 meshes with a chain 40 fixed at its righthand end, as viewed in FIGS. 3 and 4, to the conveyor bed 10 and traveling over an idler sprocket 42 rotatable on pin 44 mounted on a fixed axis. The chain travels from the sprocket 42 under the sprocket 3t) and is .fixed at its lefthand end to a pin 46 mounted in a fixed position relative to the base of the conveyor. A spring 48 (FIG. 1) urges the conveyor bed 10 toward the right in the direction of advance of the material 32, and the movement of the conveyor bed 10 is controlled by the deflection of the chain 40. That is, the spring 48 keeps the conveyor bed 10 always at the farthest righthand position as permitted by the slack or deflection of the chain caused by the sprockets 30 and 42. Preferably the idler sprocket 42 is spaced to the right of the shaft, 24 a distance substantially greaterthan the spacing of the pin 46 to the left-of the shaft 24, this lateral spacing of sprocket 42 from the shaft 24 preferably being over twice that between the pin 46 and the shaft 24.

As the crank arm 28 moves the sprocket 30 through the uppermost position of the sprocket 30, the chain 40 straightens out completely and the conveyor bed. 10 is at the extreme righthand position thereof, and stops material advancing movement of the conveyor bed and the material is thrown. As illustrated in the diagram of FIG. 5, the conveyor drive 16 gives a slow start to the feed stroke of the conveyor bed 10 so that static frictional engagement is maintained between the conveyor bed 10 and the material 32 being fed theerby, and the speed of the conveyor bed 10 is then accelerated to a high speed, which changes abruptly to substantially no feed at the extreme end of the feed stroke to give the material a toss or throw. This breaks loose the static frictional engagement between the material and the conveyor bed and causes the material to advance on farther in the feed direction. Then the drive 16 moves the conveyor bed 10 in its retraction or return stroke and comes back to its original starting position of the feed stroke, after which the cycle'is repeated.

To make more abrupt the stopping of the conveyor bed 10 at the end of its feed stroke, the path of the planetary sprocket may be such that it lifts slightly from full contact with the chain 40 when the chain 40 is fully straightened so that, during the ensuing, small portion of the revolution of the sprocket 30, the sprocket 30 is not bearing downwardly against the chain 40 although the teeth of the sprocket are maintained in mesh with the chain 40. This has'the effect of making the stop of the feeding movement of the conveyor bed 10 more abrupt and also causes the start of the retracting movement of the conveyor bed 10 to be more abrupt. Since the sprocket 30 is rotated from its movement along the chain, it may be mounted eccentrically for rotation on the end of the crank member 28, so that the throwing movement of the conveyor bed 10 and the fast return of the conveyor bed 10 are increased.

In a reciprocating conveyor forming an alternate embodiment of the invention shown in FIG. 6, a conveyor bed 60 is urged continuously to the right by tension spring 62 to the extreme permitted by a chain or strand 64 fixed at its righthand end to the conveyor bed 60 and traveling over a guide sprocket 66 on a fixed axis and under a planetary sprocket 68 carried by a crank arm 70 revolved on the center of shaft 72. The lefthand end of the chain 64 is secured to a fixed pin 75. The shaft 72 is driven by an eccentric or elliptical gear 74 which is driven by an elliptical gear 76 driven by shaft 78. The elliptical gear 76 drives the elliptical gear 74 in a movement rapidly during one-half the rotation of the gear 74 and more slowly during the other half, and the gear 74 is coupled to the crank arm 70 so that the rapid movement of the gear 74 occurs during the end of the forward feed of the conveyor bed 60 so that the throw or tossing action of the conveyor drive is maximized.

A reciprocating conveyor shown in FIGS. 7 to 9 forming an alternate embodiment of the invention includes a reciprocating conveyor bed or trough mounted by links 112 for horizontal reciprocation. The links 112 are pivotally secured to the conveyor bed 110 at the upper ends thereof, and the lower ends thereof are mounted on fixed pivots 114, and the movement of the conveyor bed is between vertical parallel positions of the links 112 and positions of the upper ends of the links 112 to the righthand side only of the vertical positions thereof. The conveyor bed is reciprocated by a drive 116 which includes an electric motor 118 driving a belt 120 to drive a flywheel 122. The flywheel 122 is keyed to a shaft 124 mounted in bearings 125 carried by vertical support plates 126 and rotates crank disc 128 also keyed to the shaft 124. The plates 126 are spaced .apart by spacers 134 and are supported by a base 136. The crank disk 128 revolves pin 130 about the center of the shaft 124. The drive 116 reciprocates the conveyor bed to feed material 132 with a throwing or tossing action toward the left, as viewed in FIG. 7, and stops the conveyor bed 110 sharply at the end of the feeding stroke of the conveyor bed to break static frictional engagement between the material and the conveyor bed, and then retracts the conveyor bed through a retraction stroke preparatory to another feed or advance stroke.

The crank disc 128 is keyed to the shaft 124 and carries the pin 130 near the outer periphery thereof. The pin 130 is connected pivotally to an elongated connecting rod or link 140, and a pivotal joint 142 connects the other end of the link to a pivotal arm 144 and a link 146 pivotally connected by a pin 148 to a clevis 150 fixed to the conveyor bed 110. The arm 144 is freely pivotal on a pin 152 mounted on a fixed axis.

The diagram of FIG. 10 shows the distance of movement of the conveyor bed relative to a fixed point. Operation of the crank member 128 causes the conveyor bed 10 to be first moved in its feeding stroke from zero to about 135, and then retracts the conveyor in the rest of the cycle of rotation. The feed stroke starts the conveyor bed slowly and accelerates throughout the feed to high speed at the latter portion of the feed stroke, then stops the feed stroke abruptly and retracts the conveyor throughout the remainder of the revolution. The high velocity of the feed stroke during the latter part thereof, together with the abrupt stop, gives a tossing or throwing action to the material, which breaks loose the static frictional engagement between the material and the conveyor bed, and throws the material on forward in the direction of advancement. This tossing or throwing action is accentuated by the action of the links 112, which are raising the conveyor bed 110 during the feed stroke to increase the static frictional engagement between the conveyor bed and the material, which raising action is lessened at the end of the feed stroke. During the return stroke the links 112 move the conveyor bed down away from the material being advanced -to lessen the frictional force therebetween. The combined action of the links 112 and the asymmetrical crank drive has the effect of throwing the material and then dropping the conveyor bed away from the material so that, during the return stroke, there is a minimum amount of friction between the material and the conveyor bed. The frequency of rotation of the.

crank member 28 is sufficiently low that excessive vibrations are avoided, and the conveyor has a very high feed capacity with low power input and with low maintenance required therefor.

In a spiral, elevating, reciprocating conveyor shown in FIGS. 11 to 14 and forming an alternate embodiment of the invention, a spiral conveyor bed 210, which is generally similar to that disclosed and claimed in our copending application Serial No. 273,672, filed April 17, 1963, now abandoned, is mounted on a cylinder 211 which carries'bearings 213 slidable on a vertical post 214. A drive 216 generally similar to the drive 116 oscillates the conveyor bed about the vertical arbor to ad vance material 232 up the conveyor bed. The drive 216 includes a base 217 on which is mounted an electric motor 218 driving a flywheel 222 through belt 220 The flywheel is keyed to shaft 224 mounted in aligned bearings 225 carried by the base 217 and a plate 223 carried by posts 221. The flywheel carries crank pin 228. The posts 221 also support upper plate 229. The crank pin 228 preferably is revolved by flywheel 222 counterclockwise as viewed in FIG. 12. A link or connecting rod 240 connects the pin 228 to a pin 242, which conmeets the link 240 to arm 244 and link 246. The arm 244 is pivoted on one of the posts 221 by hearing 252,

and the link 246 is pivotally connected to pin 249 by a self-centering bearing 251. The pin 249 is selectively fixed in one of holes 250 in arm 25S fixed to the cylinder 211, A spring 258 urges the arm 255 clockwise, as viewed in FIG. 13. The link 246 is connected by the self-centering bearing 251 for limited universal movement relative to the pin, and a self-centering bearing 159 connects the link 246 to the pin 242. The pin 242 is rigidly carried by the arm 244.

The cylinder 211 with the spiral conveyor bed is suspended from three links 270 (FIGS. 11 and 14) which in the disclosed embodiment are flexible cables but can be two connecting rod portions connected by radial and thrust hearings to each other for rotation about the longitudinal axes thereof. Self-aligning bearings 272 connect the cables 270 to a ring 274 supported by annular plate 276 in any selected, fixed position relative to the plate 276. The lower ends of the cables are connected to the cylinder 211 by self-aligning bearings 278 and pins 280 fixed to the cylinder 211. A pin 282 is adapted to key the ring 274 to the plate 276 by projecting into bore 284 in the plate 276 and one of notches 286 spaced around the periphery of the ring 274. The plate 276 is held in a fixed position by posts 288 fixed thereto and to the plate 229.

To feed the material up the bed 210, the ring 274 preferably is set in a position relative to the plate 276 such that, at the end of the retraction stroke and start of the feed stroke, the links 270 are vertical. Then, as the feed stroke takes place, the cylinder 211 turns relative to the ring and the lower ends of the links 270 swing upwardly as illustrated in broken lines in FIG. 14. This raises the cylinder 211 and conveyor bed 212 to lift the material thereon and also to press the conveyor bed more strongly against the material to increase the friction therebetween and thereby increase the feeding force. This pressing action increases progressively as the feed stroke continues due to acceleration of the lifting action from the pendulum suspension of the conveyor bed 212. On the retraction stroke, the links 270 swing back down to their vertical positions to drop out from under the material being fed. To feed the material up the spiral conveyor bed 212, the crank pin 228 is revolved in a counterclockwise direction as viewed in FIG. 12. This gives a fast return stroke and a feed-stroke as fast as possible and still hold static frictional engagement between the conveyor bed and the material. The return stroke starts very fast and the bed 212 also drops rapidly out of contact with the material to break free of the material. The trough or bed 212 can be provided with shallow steps (not show) pressed therein to enhance the feeding action, and preferably has between a 4% and a 6% grade or incline.

To feed material down the conveyor bed 212, the ring 274 is set so that the links 270 are vertical at the start of the clockwise movement of the arm 255, as viewed in FIG. 13. Then, during this clockwise feed stroke, the bed 212 is lifted by the links swinging clockwise as viewed in FIG. 14 from their vertical positions. Then, in the return stroke, the bed 212 is rapidly dropped out from the material.

The spring 258 (FIG. 13) acts as a dynamic energy storage device to aid thedrive in its rapid retraction of the conveyor bed in a clockwise direction, the spring being stretched by the relatively slower feed stroke in the opposite direction. This smooths out the load on the drive.

The above-described conveyors rapidly feed the material and with a low speed drive as compared with the speed of vibratory conveyors. The conveyors are simple, rugged and highly eflicient. While the linearly reciprocable conveyor beds of FIGS. 1 to 10 are disclosed as supported by compression links, theconveyor beds obviously may be suspended by upper links in a manner similar to the suspension of the cylinder 211 and spiral conveyor bed 212. p g

It is to be understood that the above-described arrangements are simply illustrative of the application of the principles of the invention. Numerous other arrangeintents may be readily devised by those skilled in the art which will embody the principles of the invention and fall within the spirit and scope thereof.

What is claimed is: 4

1. In a reciprocating conveyor,

a conveyor bed,

means mounting the conveyor bed for reciprocating movement along a substantially horizontal path,

a chain,

means connecting one end of the chain to the conveyor bed,

means holding the other end of the chain,

guide means positioned between the ends of the chain against which the chain continuously bears,

a crank mounted rotatably on an axis positioned substantially nearer to the holding means than to the guide means,

means revolved by the crank for engaging a portion of the chain at one side of the guide means and sub-' stantially nearer to the holding means than to the guide means for deflecting the chain as the crank means is rotated to shorten and lengthen the overall length of the chain,

and means for urging the conveyor in the direction such as to tension the chain.

2. In a reciprocating conveyor,

a conveyor bed mounted for reciprocating movement,

a crank arm rotatable on a predetermined axis,

means for rotating the crank arm,

a deflecting sprocket revolved by the crank arm,

a chain engaged by the deflecting sprocket,

means holding one end of the chain,

means securing the other end of the chain to the conveyor bed,

an idler sprocket positioned between the deflecting sprocket and the end of the chain fixed to the conveyor bed for holding the chain against the deflectmg sprocket,

the holding means being spaced substantially closer than the idler sprocket to said axis,

and spring means for urging the conveyor bed in a direction such as to maintain the chain in a taut condition.

3, In a reciprocating conveyor,

a conveyor be'd mounted for reciprocating movement,

a chain,

means holding one end of the chain at a predetermined point spaced a predetermined distance from the axis of rotation of the crank arm,

means securing the other end of the chain to the conveyor bed,

spring means for urging the conveyor bed in the direction such as to maintain the chain in a taut condition,

a crank arm,

means for rotating the crank arm on a predetermined axis,

a deflecting sprocket revolved by the crank arm along a circular path in engagement with the chain,

and an idler sprocket positioned between the deflecting sprocket and the end of the chain fixed to the conveyor bed,

the idler sprocket being spaced substantially farther than from said axis than said predetermined distance.

4. In a reciprocating conveyor,

a conveyor bed,

means mounting the conveyor bed for reciprocating movement along a substantially horizontal path,

strand means,

means connecting one end of the strand means to the conveyor bed,

means holding the other end of the strand means at a fixed point,

guide means positioned between the ends of the strand means against which the strand means continuously bears,

I D a crank mounted r-otatably on an axis positioned substantially nearer to said fixed point than to the guide means,

means revolved by the crank for engaging the portions of the strand between the guide means and the fixed point and substantially nearer to said fixed point than to the guide means for deflecting the strand means between said points as the crank is rotated to shorten and lengthen the overall length of the strand means,

and means for urging the conveyor in a direction such as to tension the strand means.

References Cited by the Examiner UNITED STATES PATENTS 1,411,855 4/1922 Loeb 7454 1,596,465 8/ 1926 Stebbins.

1,627,673 5/ 1927 Stebbins.

1,763,307 6/1930 Hoflmann.

2,818,968 1/1958 Carrier.

2,926,773 3/ 1960 Alvord.

HUGO O. SCHULZ, Primary Examiner".

EDWARD A. SROKA, Examiner.

Claims (1)

1. IN A RECIPROCATING CONVEYOR, A CONVEYOR BED, MEANS MOUNTING THE CONVEYOR BED FOR RECIPROCATING MOVEMENT ALONG A SUBSTANTIALLY HORIZONTAL PATH, A CHAIN, MEANS CONNECTING ONE END OF THE CHAIN TO THE CONVEYOR BED, MEANS HOLDING THE OTHER END OF THE CHAIN, GUIDE MEANS POSITIONED BETWEEN THE ENDS OF THE CHAIN AGAINST WHICH THE CHAIN CONTINUOUSLY BEARS, A CRANK MOUNTED ROTATABLY ON AN AXIS POSITIONED SUBSTANTIALLY NEARER TO THE HOLDING MEANS THAN TO THE GUIDE MEANS, MEANS REVOLVED BY THE CRANK FOR ENGAGING A PORTION OF THE CHAIN AT ONE SIDE OF THE GUIDE MEANS AND SUBSTANTIALLY NEARER TO THE HOLDING MEANS THAN TO THE GUIDE MEANS FOR DEFLECTING THE CHAIN AS THE CRANK MEANS IS ROTATED TO SHORTEN AND LENGTHEN THE OVERALL LENGTH OF THE CHAIN, AND MEANS FOR URGING THE CONVEYOR IN THE DIRECTION SUCH AT TO TENSION THE CHAIN.

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