US2557325A - Bucket elevator - Google Patents

Description

June 19, 195] s. T. TRANSEAU 2,557,325

BUCKET ELEVATOR Filed Dec. 31, 1947 6 Sheets-Sheet l June 19, 1951 T. TRANSEAU BUCKET ELEVATOR 6 Sheets-Sheet 2 Filed Dec. 31, 1947 I 19, 1951 s. 1". TRANSEAU BUCKET ELEVATOR Filed Dec. 51, 1947 6 Sheets-Sheet 3 June 19, 1951 s. T. TRANSEAU BUCKET ELEVATOR 6 Sheets-Sheet 4 Filed Dec. 51, 1947 June 19, 1951 s. T. TRANSEAU BUCKET ELEVATOR e Shgts-Sheet 5 Filed Dec. 31, 1947 June 19, 1951 TRANSEAU 2,557,325

BUCKET ELEVATOR Filed Dec. 31, 1947 6 Sheets-Sheet 6 llllllllllllllll [PIIIEEZ] Patented June 19, 1951 mm STATES TENT OFFICE BUCKET ELEVATOR Sherman T 'llranseau, Riverside, N. J.

Application December 31, 1947, Serial No. 795,048

C aim 1 The present invention relates to bucket elevators.

A purpose of the invention is to obtain perfect discharge from a bucket elevator employing only a single conveyor strand, so as to avoid the difiiculties inherent in multiple strand conveyors.

A further purpose is to secure in a single bucket elevator the combined advantages of the centrifugal discharge type, the continuous type and the perfect discharge type without the consequent disadvantages.

A further purpose is to avoid the limitations due to spillage, fixed speed ranges, fixed capacity ranges and maintenance difiiculties found in present elevator conveyors.

A further purpose is to employ double flex or universal joint chain or other strand on a perfect discharge bucket elevator.

A further'purpose is to employ a single strand on a perfect discharge bucket elevator without the need for cars, lugs, rollers or sliding members attached to the buckets themselves or to the sides of the chain to provide tracks for the chain, and without the necessity for inwardly acting guides inside the elevator, permitting a reverse bend in the chain just below the discharge point in order to secure perfect discharge.

A further purpose is to prevent spillage by a flanged head wheel on a perfect discharge bucket elevator.

' A further purpose is to support chain attachments laterally of the chain during loading, suitably by a flanged footwheel.

A further purpose is to increase the utility of bucket elevators in handling hot, light, fluffy, fine, coarse, abrasive, fragile or sticky material, so that all of these types may be handled with a single design of single strand perfect discharge bucket elevator without the necessity of maintaining any particular ratio between the bucket speed, head wheel diameter, bucket size and bucket spacingjall of which are necessary with present types.

A further purpose is to aid in discharge at the top of a bucket elevator by providing a head.

wheel having an imperforate rim extending laterally beyond the buckets, and preferably provided with lateral flanges extending radially beyond the rim and assuring adequate direction of discharging material into the discharge.

Further purposes appear in thespecification and in the claims.

-In the drawings I have chosen to illustrate a few only of the numerous embodiments in'which my invention may appear, choosing the forms shown from the standpoints of convenience in illustration, satisfactory operation and clear demonstration of the principles involved.

Figures 1 and 2 are diagrammatic side elevat-ions of bucket elevators to which my invention has been applied.

Figure 3 is a transverse vertical section of a simplified bucket elevator embodying my invention, illustrating the structure to enlarged scale. The section is on the line B -3 of Figure 4.

Figure 3 is a fragmentary variation of Figure 3 illustrating a change in the relation of the head wheel and snub wheel with respect to the discharge. Whereas in the form .of Figure 3 the discharge will straddle the snub wheel, in the form of Figure 3 the discharge wholly clears the snub wheel.

Figure 4 is a section of Figure 3 on the line 4-4, showing the chain and wheels in elevation.

Figure 5 is an enlarged side elevation of a chain with bucket attachment in accordance with the invention.

Figure 6 is a front elevation of the chain and bucket attachment.

Figure '7 is a fragmentary perspective showing the chain bucket attachments and buckets.

Figure 8 is a fragmentary axial section showing the foot wheel engaged by the chain andbucket attachments.

Figure 9 is a variation of Figure 8.

Figure 10 is a transverse section of a head with an imperforate chain flange.

Figure 11 is a sectional side elevation showing one form of interlock between the bucket and the bucket attachment.

Figure 12 is a variation of Figure 11.

Figure 13 is an enlarged side elevation showing the head .and foot section of a variant form of bucket elevator.

Figure 14 is a front elevation of Figure 13.

In the drawings like numerals refer .to like parts.

Describing in illustration but not in limitation and referring to the drawings:

In the prior art, the perfect discharge type of bucket elevator has been one of the commonly used types which has been quite satisfactory in some respects, but has been subject to serious limitations as set forth below, particularly because it has usually been necessary to provide a plurality of strands for supporting the buckets in order to permit engagement of the strands to provide a reverse bend below the point of discharge to accomplish perfect discharge. The use of the multiple strand has greatly complicated maintenance as noted below, so that in practice such bucket elevators have frequently been operated with gross disparities in ad ustment between the two strands or with a head or foot wheel canted considerably in order to provide adjustment. Service experience from these causes has been very unsatisfactory.

In accordance with the present invention a perfect discharge is obtained by mounting a plurality of buckets on a single strand in rows laterally displaced, providing a path between the rows for engagement by a snub wheel on the outside below the point of discharge. This is very readily accomplished without the complication involved in carrying the chain over tracks or the like.

The invention is applicable to bucket elevators whether the travel is primarily horizontal and secondarily vertical, whether the travel is primarily vertical and secondarily horizontal, or s wholly vertical. Likewise the invention is apphcable where the load-carrying containers are truly buckets and also where they are described as flights or otherwise.

As compared with the centrifugal discharge bucket elevator, the device of the invention ofiers several advantages. The centrifugal discharge type has high capacity for its initial cost due to the use of a single strand operating at high speed (often 225 to 300 feet per minute). The device of the present invention has higher capacity because it has multiple buckets permitting closer spacing per bucket on the strand at any speed even up to 300 feet per minute or more.

For the centrifugal discharge bucket elevator the buckets must be spaced rather far apart to avoid interference at discharge. In the device of the invention the spacing of the buckets is not critical in respect to the perfect discharge feature.

In the centrifugal discharge bucket elevator it is necessary to operate the elevator at high speed to get good discharge, and this increases the maintenance cost and reduces the life of the elevator especially when handling abrasive material. The device of the invention will give perfect discharge at any speed.

In the centrifugal discharge bucket elevator, the ratio of the diameter of the head wheel to the chain speed is fixed and must be held in order to get the buckets to discharge. It will be understood herein that in reference to the head wheel, foot wheel and snub wheel, the particular wheel may or may not be a sprocket, and this designation is used to indicate such wheel regardless of whether it carries sprocket teeth. Once the particular elevator is designed, built and installed, for certain material at a given capacity, it is very difficult to change the material or the capacity. If the device is operated at a slower speed than that for which it was designed, material will drop from the buckets and fall back down the elevator without entering the discharge when the buckets are passing over the head sprocket. If operated at a higher speed than that for which it was designed, buckets may pass below the oint of discharge without discharging. The actual capacities of many centrifugal discharge bucket elevators as measured by field tests do not exceed to percent of the rated capacities. In the device of the present invention the diameter of the head wheel is fixed by the maximum speed (for example 300 feet per minute) and perfect discharge is obtained at all speed ranges. The speed of the elevator and the type of material can be changed at any time without affecting the discharge.

In the centrifugal discharge type, large expensive casings are required, but it is diflicult to obtain great strength because the width is extremely narrow. The large casings necessitate excessive floor space in a building when the elevator is installed indoors. In the device of the invention, a smaller casing taking up less space will serve for a given capacity The casing, while smaller, is structurally stronger because of the depth of the transverse section which gives it the shape of a box girder.

The continuous bucket elevator has the special advantage of high capacity at slow speeds to feet per minute) due to very close spacing of the buckets. It does not depend on centrifugal force to discharge. The device of the invention offers high capacity due to the multiple rows of buckets which may be spaced continuously on the chain and can be loaded and unloaded at any speed up to very high speeds such as 300 feet per minute.

The continuous bucket elevator has the disadvantage that it requires a loading leg to load the buckets and therefore needs a deep pit. The device of the invention does not need a loading leg, and, with take-up on the head shaft, only a very shallow pit is needed. This is important if the elevator is to be located in a plant along the river front.

The continuous bucket elevator requires greater head room at the discharge point while the device of the invention can operate with less head room, thus avoiding the necessity in many cases of projecting the head of the elevator through the roof of the building.

When handling light, fluffy materials, a large percentage of the material fails to jump over the space between the outside face of the bucket and the discharge chute in the continuous bucket elevator and falls back down the elevator casing. In the device of the invention, the flanged head wheel at the discharge prevents this, as well as the extension of the periphery of the head wheel over the discharge. Any material falling out of the buckets when they are passing over the head wheels at slow speeds will nevertheless reach the discharge chute.

The perfect discharge bucket elevator of the prior art has the advantage of slow speed (100 to 150 feet per minute), and has ideal discharge due to the employment of snub sprocket just below the point Of discharge permitting the buckets to invert over the discharge chute. This type of elevator is especially well suited for the handling of light, fiuffy, dusty, aerated, fragile and sticky materials that will not discharge cleanly in other types of elevators. It is very quiet in operation. All of these advantages are also possessed by the device of the present invention.

The conventional perfect discharge bucket elevator is subject to the difiiculty that the buckets must be spaced far enough apart to avoid interference at the point of discharge. This reduces capacity, especially as the elevator is operating at slow speed. In the device of the invention due to the multiple buckets, the average bucket spacing can be quite close without interference with perfect discharge at all speeds.

In the conventional perfect discharge bucket elevator an extremel large casing is required for an elevator of small capacity. For a given capacity, the device of the present invention has a smaller casing and requires less space than in prior art bucket elevators.

The conventional prior art perfect discharge bucket elevators due to their slow speed and the bucket spacing, have a certain amount of ma.- terial spill out of the buckets 'backdown the Gas-.- ing when passing .over the head sprockets. 'In ac, cordance with the present invention, due to the flanged head wheel, material is not able to fall down the casing, but instead goes into the dis.- charge.

The prior art perfect discharge bucket ele-. vators have been very expensive in regard to ini tial cost for a given capacity. This is due to .the fact that they have required at least two strands of chain (100 percent more than other types), and 2.00 percent more sprockets, shafts, bearings and other moving parts than other types. These elevators have been the most expensive in both first cost and maintenance of all bucket elevator designs. The device of the invention, on the other hand, is not expensive in first .cost .or in maintenance. Only one strand of chain is required and only a half .as many main sprockets and other moving parts as prior art perfect discharge bucket elevators.

The perfect discharge bucket elevators of the prior .art have been a continuous source of trouble .and expense due to uneven stretch and wear in the two strands of chain. Operators who are unable to see the takeeup shaft tighten bothtakeups to the limit, throwing the takeeup shaft far out of level due to the uneven lengths of the chains, resulting in frequent binding and burning out of take-up bearings and .binding of chains on the sprockets due to lack of alignment. In normal practice, such prior art perfect discharge bucket elevators have been dismantled several times each year, disassembling the chain and buckets. Each strandof chain is taken apart into small sections, and switched from side to side inorder to equalize the lengths of the two strands. In case abrasive materials are handled and the elevator is loaded off center, this dismantling is usually necessary everymonth.

Because of this difficulty perfect discharge bucket elevators are rarely used in modern work. Ihe device of the present invention, havingonly a single strand, is not subject to any difference in stretch or wear. This eliminates all of these-bad features in the prior art machines. Furthermore, since this is a single strand machine and can usually have a. wrap around the head or drive wheel of 225, teeth are not required on either the head or foot wheels. This increases the life of both chain and Wheels by at least 1-00 per cent. This also eliminates the expense and trouble of providing shear pins and slip couplings or fluid couplings which are usually used.

-In the prior art perfect discharge bucket elevators, the chains have been attached to the sides of the buckets and due to necessaryclearancebetween the chain and the elevator casing, large space is required in the boot in which material collects. The continual passing of the chain through this dead storage results in extreme wear on the chain if abrasive materials are being handied. I thedevicenf the present invention there is no necessity to use any such large storage space in the elevator boot and therefore wear is minim z d- As seen in Figure 1, the bucket elevator .of the invention comprises a single strand 120 of any suitable flexible material, which may be chain, woven flexible metal, fabric, rubber, synthetic rubber or the like, guided over suitabl means for directing the travel of the strand, shown as consisting of foot ,wheels 21,. making a return bend '22 at the feet. a head wheel 23 making 18.- return bend 24 at the head, a discharge :25 below the head wheel and extending beneath its periphery 26 on the forward side of the conveyor, and a snub wheel 21 which engages the strand below the discharge out of line with the-buckets to produce a reverse bend 28,

The conveyor is guided over auxiliary wheels wand .31 to produce an inclined stretch :32 be: tween essentially vertical stretches :33 and 39.v

As shown in Figure 2, the arrangement ofv ins clined and vertical portions may be varied, in this case by employing a short upper stretch 34" which is vertical, followed by an inclined upper stretch 34 above the vertical stretch.

As best seen in Figures 3 to 12 inclusive, the preferred embodimentof the invention has a head section 35 equipped with a discharge 25 extend.- ing in beneath the periphery of the head 'wheeil Z3 .oneach side of the snub wheel, .on the forward stretch .of the conveyor as shown. The head wheel is mounted in a shaft 3.6 on suitable bear.- ings {i1 and provided with a power driving con, nection at :38, where drive is accomplished through the head. A casing .40 extends vertically or conforming to the desired path of the con.- veyor and connects at its lower end with foot section 4| including a boot, having an at 4:2 and provided with a foot shaft .43 in bearings 44 mounting a foot wheel (sprocket) 2|. It will be noted that the chain engages the head wheel for approximately 225 and engages the foot wheel for approximately 180. Takeup may be provided in any suitable way on the head shaft or the foot shaftas wellknown.

The preferred strand consists of a single endless flexible chain which is of universal pr reverse bending character. The chain is bestshown in Figures 5, 6 and 7 The chain consists of ordinary links 45 interspersed by attachment links-45 in any suitable ratio depending upon the desired spacing of the buckets, here shown as two plain links to one attachment link. Each of the links has a barrel and side bars 48 whichextend from the barrel outwardly to span the next ba-rrel and permitconnection with the next link 'by a pin 50. This aspect of'the chain constructionis not to be regarded as novel, and it will be understood that any suitable basic design of bucket conveyor chain may be employed, with variations in design to meet the individual requirements.

The pivot relation between the respective links at th pins is such that the links are free to turn both inwardly and outwardly through a suitable angle corresponding with the maximum bend of the chain in each direction.

From the link arms 48 of the attachment links extend at each sidepreferably integral therewith lateral attachments 5| which are entirely beyond or on either side of the path openings 52 between the link side bars and th line of the barrels 4-1 which will be engaged bythe head wheel on the inside or by the snub wheel 21 of the present invention on the outside as later described.

Each attachment carries a bucket 53 and each bucket is in a row laterally displaced from another row of buckets so that there are a plurality of buckets in the laterally displaced rows as will be seen in Figure 4, where one row is designated 54 and the other 55.

The attachments may be conveniently secured to the buckets by any suitable fastenings such as bolts 56 extending through suitable cooperating openings in the attachments and buckets as shown. The bolts are conveniently accessible for 7 application and removal through the openings 51 at the forward faces of the buckets.

To further assist in anchoring the buckets, one or both edges of the attachments are provided with key projections 58 and 60 to engage and interlock with cooperating key recesses 6| (Figure 11) or BI and 62 (Figure 12) so that the bucket can be slid on from the side and securely fastened as by the bolts. This protects against angular load on the bolts, loading the bolts merely in shear and chiefly laterally, so that the rivets will remain tight indefinitely even under considerable vibration.

Suitable integral strengthening ribs may extend longitudinally of the attachments as at 63 to better support them from the link side bars.

The longitudinally extending ribs as best seen in Figure 8 are conveniently provided with base abutments 64 which are in line with the inner edges of the link arms of the chain and which provide Outriggers for engagement with a flange 65 of a flanged foot wheel 21. This supports the two buckets mounted on a given attachment link equally from the two sides when the conveyor is loading or digging unevenly and assures against the effect of a diagonal force component applied to the buckets which might damage them or excessively wear the conveyor.

The inside faces of the link side bars extend back beyond barrels 41 on the inside of the chain as will be seen at 66, and this portion of the chain is guided by a radial flange or rim 61, preferably provided on both the head and foot wheels. This radial flange may be a sprocket as shown in Figure 3 or it may be an imper-forate guiding rim as shown at 61 in Figure 10.

It will be evident that the wall of the discharge 25 which is nearest to the conveyor and which will in the best form of the invention actually extend in beneath the periphery of the rim of the head wheel must avoid interference with the snub wheel and snub shaft, and also with the buckets as they take their reverse bend. In the form of Figure 3 the adjoining wall of the discharge is suitably recessed or split so that it can straddle the snub wheel as shown. It will be evident, however, that this may present the disadvantage of exposing the snub wheel directly to the material being handled, and where desired the snub wheel may be mounted entirely outside of the limits of the discharge as shown at 25' in Figure 3, in which case the adjoining wall of the discharge is above and to the rear of the snub wheel, but nevertheless extends beneath the periphery of the head wheel on the forward sideof the elevator.

In some cases the support needed is more than that which can be well provided by the construction of Figure 8 and in such instances radial circumferential flanges are provided at the ends of the foot wheel as indicated at E8 to engage the outside end portions 16 of the attachments and further support the pairs of buckets against diagonal stresses during digging. (See Figure 9.)

It will be evident that lateral support beyond the line of the chain proper may be provided in any suitable way to prevent the effect of angular stresses during loading. The same support may also be given as in Figures 8 and 9 in discharge.

The head wheel employed in th present invention as shown in Figures 3 and 4 may be flanged at ll so that there is a solid circumferential portion extending in both directions from the chain endwise under the buckets and any material which may drop out of the buckets intermediate the travel of the buckets over the head wheel is picked up on the drum-like head wheel and carried over to the point 24' where its periphery extends vertically beyond the discharge on the forward side, and there dropped into the discharge. The combination of the imperforate rim and the radially extending side flanges 2i laterally beyond the buckets greatly assists in discharge, since any material which escapes from the buckets prematurely during the travel of the head wheel is caught from below by the imperiorate rim of the head wheel and carried to a point where it will drop into the discharge, and at the same time is laterally confined and guided by the flanges H to prevent premature spillage from the ends of the head wheel. The discharge should of course be adequately wide to receive all material contained between the limits of the flanges H, and to provide for the possibility that some material may be carried by the head wheel beyond the sides of the buckets.

On the forward side of the head wheel beneath the discharge the snub wheel 21 already described extends into the open outer face of the chain along the path provided by the spaces between the rows of buckets, engaging the chain and guiding it in a reverse bend 28. A snub shaft 12 supports the snub wheel in line with the path between the rows of buckets and turns in suitable bearings 13.

It will be evident that the snub wheel need not be a sprocket as shown in Figure 3 but may be a plain snub wheel as shown in Figure 13.

In many cases it may be preferable to use a strand of other character rather than a chain, and a belt 14 of rubber or the like is shown in Figures 13 and 14. It will be evident also that the number of multiple rows may be greater than 2, and in Figures 13 and 14 I show a construction having multiple rows of buckets 15, I6 and 11 having paths 18 and between the rows for engagement by snub wheels 8| and 82 (generally designated as 27) which in this case are smooth and not sprocketed. Extra engagement paths for snub wheels 83 and 85 are provided on the outside lateral sides.

It will be evident that the chain is open for access by guiding wheels on paths both on the inside and on the outside and that the fixed buckets are placed on either side of the engaging path.

In view of my invention and disclosure variations and modifications to meet individual whim or particular need will doubtless become evident to others skilled in the art, to obtain all or part of the benefits of my invention without copying the structure shown, and I, therefore, claim all such insofar as they fall within the reasonable spirit and scope of my claims.

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

l. A bucket elevator having a single endless flexible conveyor strand extending up to a reverse bend at the head and generally vertically downwardly on the discharge side from the reverse bend, a head wheel guiding the strand on the inside of the reverse bend, buckets fixedly secured to and supported wholly from the strand in a plurality of laterally spaced rows, leaving the strand open on the inside and outside between the buckets, a snub wheel engaging the outside of the strand between the buckets of two rows immediately below the head wheel on the discharge side and deflecting the strand in under the periphery of the head wheel and a discharge chute outside the strand which extends in under the periphery of the head wheel on the discharge side.

2. A bucket elevator having a single flexible endless conveyor strand extending up to a reverse bend at the head and generally vertically downwardly on the discharge side on the reverse bend, buckets fixedly secured to and supported wholly from the strand in a plurality of laterally spaced rows, leaving the strand open on the in side and outside between the buckets, a head wheel guiding the strand on the inside of the reverse bend and having a rim which extends the full width of the buckets and is adaptable to deflect material into a discharge chute, a snub wheel engaging the outside of the strand between the buckets of two rows immediately below the head wheel on the discharge side and deflecting the strand in under the periphery of the head wheel and a discharge chute outside the strand which extends in under the periphery of the head wheel on the discharge side and receives material from the rim on the head wheel and directly from the buckets.

3. A bucket elevator having a single endless flexible conveyor strand extending up to a reverse bend at the head and generally vertically downwardly on the discharge side from the reverse bend, buckets fixedly secured to and supported wholly from the strand in a plurality of laterally spaced rows, leaving the strand open on the inside and outside between the buckets, a head wheel guiding the strand on the inside of the reverse bend, having a rim extending the full width of the buckets and having radially outwardly extending flanges at the opposite ends of the rim beyond the buckets, a snub wheel en gaging the outside of the strand between the buckets of two rows immediately below the head wheel on the discharge side and deflecting the strand in under the periphery of the head wheel and a discharge chute outside the strand which extends in under the periphery of the head wheel 10 on the discharge side and receives material from the rim and directly from the buckets.

4. A bucket elevator having a single endless flexible conveyor strand including bucket attachment links and extending up to a reverse bend at the head and generally vertically downwardly on the discharge side from the reverse bend, a head wheel guiding the strand on the inside of the reverse bend, buckets making interlocks with the bucket attachment links, fixedly secured to and supported wholly from the same in a plurality of laterally spaced rows, leaving the strand open on the inside and outside between the buckets, a snub wheel engaging the outside of the strand between the buckets of two rows immediately below the head wheel on the discharge side and deflecting the strand in under the periphery of the head wheel and a discharge chute outside the strand which extends in under the periphery of the head Wheel on the discharge side.

5. In a bucket elevator, a single endless flexible chain, bucket attachments on either side thereof having bucket interlock surfaces, and buckets fixedly mounted on the attachments in spaced rows on opposite sides of the chain and having bucket attachment interlock surfaces which engage the bucket interlock surfaces on the bucket attachments.

SHERMAN T. TRANSEAU.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 269,295 Kirby Dec. 19, 1882 448,699 Underwood Mar. 24, 1891 526,405 Miller Sept. 25, 1894 572,448 Ream et a1 Dec. 1, 1896 728,972 Pittman May 26, 1903 1,109,986 Harrison Sept. 8, 1914

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