CA1263335A - Belt conveyor - Google Patents

Abstract

BELT CONVEYOR
Abstract A belt conveyor having a frame located inside whereof are two lengthy pliable members which are interconnected by medial idlers. A plurality of side idlers are supported on fulcrum pins which make each an angle with a plane through the pliable members and are connected to these members with pro-vision for displacement integrally therewith in a vertical plane. Linking means are also provided for which connect each to the respective folcrum pin with one end so as to make an angle therewith and are pivoted each to the frame at the outward sides of the pliable members with the other end with pro-vision for unobstructed swinging in a plane perpen-dicular to the axis of the conveyor. Said pivoted joints are located substantially not below a plane through the pliable members.

Description

1~633~35 Technical Field The invention rel~tes to materials handling equipment and iY specifically concerned with belt conveyor havin~ an andless load-carryin~ member.
The inventio~ can be advantageous i~ conveyin~
~ranular a~ tic!~y building materials on construc-tion sites and in the buildinp, industry, large lump rock at mines.
Back~round of th~ Invention ~ ihatever the application, e~ective operation o~ belt conve~ors depends on mecnanical and physic-~1 properties, size and shape of the loads handled.
The larger the lumps a belt conveyor of a ~iven de-sign can accommodate and the ~aster the belt speed, the higher the e~fect o~ the equipment in operation.
~his is particularly true in the mining and building industries.
1'here is known, ~or example. a belt conveyor ( c~. Rotec Creter Crane-125-24~ Parts and Mainte-nance, Operation Instructions, Assembly and Sa~et~
Rotec Industries, Inc.) incorporatin~ an endless belt, a drive and a ~rame. A plurality of m~dial idl-ers ~lanked by inclined side idlers o~ the cantilev-er type at eith~r end are ~itted to the ~ram~ o~e next to the ottler. Irop side idler~ are provided at ~ . - . - . . .

the sides o~ the belt sabstenti~lly at ri~ht angles to a plane therethrough and in contact therewith to train the belt correctly ap~rt from the medial and side idlers.
Givin~ sneed~ and e~ective service, this de-sign is not free, however, from some silortcomings.
It CanrlOt h~ le lar~ lumps because the top side i~lers hamper their procress and because the impact loads they impose on ~he medial, side and top side lO idlers are detri~ental to the inte~rity of the idl-ers lacking a shock-absorbing mounting. In training the belt along the a~is o~ the conveyor, the top side idlers bear upon the belt edge within a narrow area o~ contact. The resultant unit load is high, 15 brin~ing about ply separation and slipping o~ the belt, ~ear on top side idlers.
Not excluded is the possibility o~ train-ing the belt. It may result accidentally if, for ex-~mple~ th~ dirt or dust entering so~e of the bearings 20 impedes the rotary motion oi th~ idlers they support.
Ill-training of th~ belt can also be caused by an out-o~-square of idlers relative to the axis o~ the conveyor due to inaccurate installation Or the con-veyor. The known design i~ deprived o~ any means 25 ~ controlling the path o~ the belt ~hen the convey-or i.q in operat~on and train the belt accurately along the axis thereo~ so that the function of the 12~335 top side idlers ~.vould be a standby ~ne.
In practice~ the trainin~ of the belt is accom-plished in the foLlowing way. 0~ spotting a malfunc-tioning idler vhich causes belt misalignment, the co~veyor is stopped and the material it carries is unlolded. The faulty idler is turned through an angle in plan the magnittlde ~h~reof is selected by the p~rson in charge subjectively, on the basis o~
his skill and experience. Commonly, this angle is 1-~ as measured from a plane at right angles to the axis o~ the belt in the clockwise direction il' the belt travels awa~ ~rom the point of observation ~nd tends to misalign t~ the left. '~he idler turn-ed as indicated interacts with the belt resiliently slipping past it and gives rise to a ~orce which is applied to the belt and tends to displace this in the direction opposite to the direction of mi~alignment, bringing at balance the force which has caused th~
ill-trainin~ of tha belt. However, th~ arbitrarily selected an~le of turn and a possible mist~ke in identifying the exact idler causing the misalignme~t commonly render this method of control useless.Since no additional wa~s Or controlling the t~aining of the loaded belt on th~ go exi9ts in thi~ case, as this was pointed out above~ thR top side idlers con-taeting the belt edges are the last resort in spite of their rapid wear and ply separation of the be~t.
-- 4 _ -~263;33~

Also known is a belt conveyor of another de-sigrl (cf. USSR Inventor's Certi~icate No. 346,192;
IPC 3 65 g 21/04~ dated December 21, 1970) incorpo-ratin~ a study fra~ework a~ld at least two pliable load-carryin~ members o~ considerable len~th wh;ch are tensioned, extend inside th~ framework esseQti-ally parallel to each other and to the axis o~ th~
conveyor an~ are linked to said framework so as to be supported in a given position. ~he ~rame~ork is also provided with a means of tensioning said pli-able load-carrying members. A plurality of medial rolling- means are located between th~ pliable memb-ers substantiall~ at ri~ht angles thereto and are spaced a di~tance apart ~rom one another along the conveyor. a plurality of fulcrum pins are located substantially at right an~les to the pliable memb-ers 90 that their supportin~ ends are connected to the pliable mel~bers with provision for displacing integrally therewith in the vertical and horizont-

2~ al planes. ~he ~ulcrum ~ins are disposed on ei~herside Or said pliable members externally thereto and spaced a distance apart ~rom one arloth~r. '~hey car-ry a plurality of side rollers. A plurality o~ link-ing means the number ~;~hereof equals that o~ the 25 fulcrum pins is also provided for. ~he linking me-ans are rod9 located sub9tantially parallel to the Yulcrum pins and rigidly attached each to the res-pective side rollin~ ~ans (idler) ~nd to the pli-... .

able member as well. ~ac~ linking mearls is alsopivoted to the sturdy rramework with one of its ends, whereb~ the pivoted ,joint betweeLl tnis link~ng mean~ and the ~ramework is located at tne inward 5 side of' the respective pliable member below a plane through tnese members. The belt conveyor also incor-porates an endless belt ana a belt drive.
These features of th~ design enAble the convey-or to handle large lump materi~l at a sDeed not less than ever before. The rolling means (idlers) are so attach~d to both the ~ramework (frame) and the pli-able me~bers tnat they can yield under ilupact loads, greatly reducing thereby the e~fect ol' these loads on components of' idlers and frame. But there is evi-dence tnat belt training appears to be a problem in this case.
~he recourse to to~ side idlers is nardly prac-ticable, for it will limit the size of lump materi-al handled due to reasons given above.
~he te~dency OL' the belt lor ill-training seems to be unavoidable. It can be spurred spontaneously by a slu~gish operation of a ~r~up of idlers due to dust in th~ir bearings no matter how acc~r~telY
these idlers have been fitted at rignt angles to the axis of th~ belt. '~he pliable members whicn are co~monly steel wire ropes are likely to elongate in operation due to strain relaxation u~der tensile loads with the result tha6 idlers, esp~cially those ~26~3~

at the sides, get out-of -true in plan and create favourable co~itions for belt-misalignment forces to come into play. Since the linkin~ means are lo-cated at the in~ard si(les o~ the pliable members be-5 low a plane therethrough, th~ side idlers can yieldunder impact loads but the troughing of the belt de-creases when the pliable members aisplace downwards.
With the diminishing o~ the amount of troughing o~
the belt, the pressure the side idlers exert o~ the 10 belt decrea9es and so does the tilt of these idlers.
Thus conditions are created whicn facilitate belt misalignment. ~uring a spontaneous occurence of the event, the pressure sustaine~ by the side idlers towards wrlich the Delt aisplaces increases and that 15 comi~g on the opposite side idlers ~ecrease~. 'l'he side idlers, ~eing connec~ed through the linking means to the pliable members which deform directly with the load they sustain, tilt at the side displac-ing toward~ which is the belt at a lesser degree 20 than at the opposite side. Such positioning of the side idlers invites dif~iculties for the belt to re-turn into alignment with the conveyor axis.
The known design also creates no prospect of controlling tbe position of side idlers when the belt is carrying load. An arbitrary adjustment of their position can be made only on stoppin~ the con-veyor. ~here~ore, accurate training of the belt is ~ 7 --; ,, i2~3~;

~ormidable problem in operating the known conveyor.
Large and medium lumps o~ the material carried can collide with side idlers, causin~ t~ese to de-~flect and vibrate. The amplitude of the vibration increases with t~e height of idlers so that the lumps contacting idler tops get an acceleration high eno-ugh for them to bounce of~ the belt.
It is an object of the invention to provide a belt cooveyor of a design capable of conveying bulk and sticky building materials or large lump rock ow-ing to an ability of the side rolling means to yield.
Another object of the invention is to ensure accurate belt training.
A further object vf the invention is to create conditions permitting positional control of the rol-ling means to be exercised when the belt i9 on the go .
Summary of the Invention These objects are materialized in a belt coo-veyor comprising a s~urdy framework extending ~ulllength o~ the conveyor; at least two lengthy pliable load-carrying members which run inside said frame-work substentially parallel to each other and to the axis of the conveyor and are linked to said ~rame-work so as to receive support in a given positionrelative thereto; a means o~ tensioning said pliable members inside said ~rame~ork~ a plurality of medial _ ~ _ ~26~3~

rolling means which are located between said pli-able member9 9ubstantially at right angles thereto and are spaced a distance apart from eac~ other along thereo~; a plurality o~ fulcrum pins located sub-sta~tially at right angles to said pliable memberso that the supporting ends o~ said ~ulcrum pins are connected to said pliable ~embers with provision ~or displacing integrally therewith in the vertical and horizontal planes; a plurality of side rolling means which are fitted to said rulcrum pins on ei-ther side of said pliable ~embers outwardly thereo~
and are space~ a distance apart ~rom each other;
a plurality of linking means each whereol is rigid-ly attached to tAe respective said fulcrum pin of side rolling means with one end, making an angle therewith, and is pivoted to said ~ramework with provision for unobstructed swinging in a plane per-pendicular to the axis o~ the conveyor with the other end; pivoting means which connect said other ends o~ said linking means to said ~ramework and are located thereon along the outward sides o~ ~aid-pliable members substantially not below a plane theretbrough; an endless conveyor belt resting on said medial and side rollin~ means; a drive o~ said conveyor belt.
This arran~ement renders the side idlers cap-able of yielding under a load and reduces the ampli-_ 9 _ ~Z~i333~ii tude of vibration at idler tops. T~e per~ormance of the belt supporting means under impact loads im-proves to a point when large lumps can be carried without difficulty anc wit~ ~ lesser probability 5 of bein~ thro~n off the belt. ~he ~act that the pi-voting means are located alon~ the outward sides of the pliable members permits positional control of the side rolling means to be exercised when the belt i9 loaded and on the go so a~ to prevent its mis-10 alignment and thus improve the operational reliabi-lity o~ the disclosed conveyor. When the belt mis-aligns and moves to a siAe, the pressure on the side rolling means at this side increases and ~o does their tilt with the re~ult that ~urther sidewise displacement of the belt is checked. A decrease in the pressure on, and in the tilt of, the side roll-in~ means at t~e opposite side of the belt facilitate the restoration of its alignment.
It is expedient to connect ~he linking means to ~0 the sturdy frame~ork with provision ~or turning about tneir axes within a given limit. The side rol-ling means will then be able to tilt in the plane of the belt and in the airection of belt travel aft-er colliaing with lumps carriea by the conveyor, whereby the angle of tilt will be greater at the top of the rollin~ means than at the bottom. ~he side rolling means will thus turn ~hrough a limited ~2~i3~

angle in the plane o~ the belt clockwise at the le~t-hand side of the belt and counter clockwise at the ri~;ht-hand one loo~ing ir the directiQn of belt travel. The contact o~ the belt witrl the side roll-ing means turned as indicated above gives rise toa ~orce actin~ on the belt an~ directed towards the axis of the conveyor. When the belt travels in ali-gnment with the axis o~ the conveyor, the side roll-ing means to the right and le~t o~ the belt average roughly an equal number of collisions with lumps in the same directions. The ~orces set up at the right- and le~t-hand side idlers are at balance and the belt training is correct. A sidewise displacement of the belt imposes a greater load on the side roll-ing means towards which shilts the belt than on the side rolling means at the opposite side and the forces resulting from collisions with lumps are higher at the former side rolling means than at the latter. The side rolling means exposed to higher 20 forces tilt more heavily than their counterparts sustaining lighter forces, and the forces the ~rm-er e~ert on the belt in the direction of the axis o~ the conveyor are higher than those coming from the latter. Thus, an aligning force equalling the di~ference between the opposing rorces and tend-ing to restore belt alignment comes into existence.
The linking means which are capable o~ turning ~26~33~i about their axes enhance the alignin~ potency oi the disclosed design.
It is also expedient to connect the linking means to the rramework so that the top ends o~ the side rollin~ means displace in the diIection of belt travel when the Linking means are being turned thro-ugn a limited angle, whereby the rolling means tilt relative to the pliable members and t~e axis of the belt through an angle of 2-3 with the perpendicular.
AS already pointed out, the side rolling means tiLting in this way facilitate the restoration of belt align~ent. ~he optimum magnitude of the tilt has been determined experi~entally. The force which is set up due to a ~elt-to-idler contact and acts 15 sidewise increaseS directly with tlle tilt o~ the idler in the plane o~ the belt through aQ an~le o~
0-3 with a plane perpendicular to the axis o~ the belt, but sharply decreases when the tilt is over ~. 'l~ne explanation is that over the range of tilt 20 be~ween 0 and 3 the belt slides over the idler with some amount of spring so that the-side-~ise direct-ed ~orse materializes due to a coefficient of sta-tic friction. When the tilt exceeds ~, the belt sliding goes on uninterruptedly and the sidewise 25 directed force materializes due to a coe~icient o~ sliding rriction which is smaller than the coer-ricient of static ~riction. The force in question ~Z~33~;

consequently decreases sharply. It stands to reason that the tilt of the side rolling mea~s between 0 and ~ is a~ optimum plan.
It is ~urther expedient to connect the linking means to the fulcrum pins of side rolling means substeutially at au angle of 10-65. The upper limit of the angle is decided bg the elasticity of the belt and the lower one is de~ined by the ability of side rolling means to tilt i~ the plane of the belt.
It is prererred to connect the supporti~g ends of the fulcrum ~ins o~ side rolling means to the pliable members with the aid of longitudinal rests, whereb~ each of the rests is secured to the respec-tive ~liable ~ember at least within a portion of its 1~ lenKtn making a right angle ~ith the rulcrum pin that is attached to the rest.
~ his plan creates the most ravourable condi-tion ror correct belt training, provided the ~actors ~lhich determine the amount of tilt ( 2 or 3 as indicated above) of the side rolling means in plan -- the length of the restsl that of the portion of each rest secured to the pliable member and the ten-sioning of the pliable members -- are selected cor-rectly. The side rolling means need not be checked ror perpendicularitg with the axis of the conveyor in installin~ the conveyor if the fulcrum pins of these rolling means make right a~les with those 1~ -.

lZ63335 portions of th~ lon~itudinal rests which are secured to the pliable members.
The rests can be connected to the pliable mem-~ers VJit~ provision Ior relative displacement, where-5 by each linking means will be capable o~ shif~ingalon~ its axis within a limite~ ~istance and turn-ing about the a~is through a limited angle so as to provide for a deflection o~ the side rolling ~eans through 2 -3 from the vertical to the pliable memb-10 ers. This will prevent the side rolling means ~rombecoming out-o~-square due to elongation of the pli-able members u~der tensile loads. The same result can be obtained if the rests are rigidly secured to the pliable members within at least a portion of 15 their length. The linking means must also be con-nected to the framewor'~ with provision ~or limited displacement therealon~ and turning about their ax-es through a limited angle.
It is also preferred that the fulcrum pins o~
20 side rolling means and the linking means are rigidly attached e~ch to the respective rest at the oppo~its ends thereo~ and are so located on the conveyor that each ~ulcrum pin of side rolling means trails the respective linking mea~s in the direction of belt 2~ travel.
Each of the pliable members attached whereto is the rest will bend in this case wi~h the result that the mitigating belt training e~fect of the ~2~ 3~

side rolling means will be enhanced.
The linking means can be made each integrally with the respective rest to simplify construction.
It is further preferred that the linking means are each connected to the framework with one of its ends with provision for changin~ the point o~ con-tact in the vertical direction. This will permit the control of the tilt of each side rolling means to be exercised when the belt is on the go, either loaded or ~ot. An increase in the tilt of side rolling me-ans within certain limits facilitates correct belt training as pointed out above.
Brief Description of the ~rawings A pre~erred embodiment of the invention will now be described in detail by way o~ examples with re~erence to the accompanying drawings in which Fig. 1 is a schematic plan view o~ the convey-or according to the invention;
h~ig. 2 is a side elevation of the conveyor sho~n in Fig. l;
Fig. 3 is a general ~iew of the framework, pliable load-carryin~ members, rolling and linking means, rests illustrating their mutual disposition according to the invention;
~ig. 4 is a view of a side rolling means de-picting a diagram of the forces acting thereon and on the belt according to the invention;

lZ~

Fig. 5 is a view illustrating the operating principle of a siùe rolling means in a plane at right angles to the pliable load-carrying mea~s;
Fig. 6 illustrates the operating principle of a side rolling means in the plane through the belt and a dia~ram o~ the forces acting o~ the rolling means and belt;
Fig. 7 illustrates the way the linking means are connected to the rramework in an embodiment of the invention which provides rOr a movable link between every rest and the pliable load-carrying member;
Fig. 8 illustrates the way the linking means are connected to the framework in an embodiment of the invention which provides for a rigrid link bet-ween every rest and the pliable load-carrying memb-er.
Detailed Description o~ the Invention A belt conveyor comprises an endless belt 1, a sturdy framework 2, a drive pulley 3, a take-up pulley 4, medial rolli~g means-5 and side rolling means 6 which support the carryin~ run of the belt 2 and rolling meaas 7 resting whereon is the return run o~ the belt (Figs. 1 and 2). A pair of pliable loa~-carrying members 8,9 operate inside the frame-work 2. Tensioning means 10 serve to tension the pliable members 8 and 9. 'l'he medial rolling means . - 16 -- - -. . :

~Z63335 5 ~Fig. 3) are ~itted between the pliabl~ members 8,9 a~d are s~aced a dista~ce apart from each other.
The side rolling means (idlers) 6 are fitted to ful-crum pins L1 whicrl are located on either side of the 5 pliable members 8,9 outwaraly thereof and are spaced a distance apart ~rom each other. The fulcrum pins 11 are located su~stantially at right angles bo the pliable members 8,9 and their supportin~ e~ds 12 (Figs. 3, 7 and ~) are connected to th~ pliable mem-10 bers 8, 9 with provision ~or displacing integrall~therewith. Every fulcrum pin 11 giving support to the side idler 6 is provided with a linking means (tie rod) 13 which connects to the fulcrum pin 11 and makes an angle therewith. The tie rod 13 is con-15 nected to the framework 2 with one end with provi-sion ~or unobstructed swingin~ in a plane at right angles to the axis o~ the conveyor. T~e connection o~ the tie rod 13 to the framework 2 is e~ected by means o~ a pivot 14 (Fi~. 3). The tie rods 13, the fulcrum pins 11, the side idlers 6 and the pliable members (steel ~ire ropes) 8,9 are-so located r~-a-tive to each other that the tie rods 13 extend to-wards the ~ramework 2 and are attached thereto by pivots 14 which are located not below a plane throu~h the pliable members 8,9. '1'~ ~ramework 2 can be pro-vided in the form of a sturdy truss or a plurality o~ isolated stanchions which are made o~ rolled or , - 17 -e~truded shapes and rest on a firm base (e.g~ the ground). I~he framework will be referred to herein-after as frame 2.
This layout provides for yielding of idlers 5 and therefore reduces the impact loads sustained by components o~ the belt conveyor. The medial idlers ~ deflect downuards after a collision with lumps of the material handled and side idlers 6 de-~lect in a plane perpendicular to the axis of the 10 conveyor as shown in Fig. 5 by dashed lines. The tilt of the de~lecting side idlers 6 increases whe-reby the amount of sidewise displacement of these idlers at the bottoms is greater than that at tne tops. The attitude of side idlers during a collisi-15 on with Lumps minimizes the losses of material. Asidewise displacement o~ the belt out of alignment with the conveyor ~2iS ~rings about a redistributi-on of the loading sustained by the wire ropes. A
belt displaceme~t to the right increases the load 20 on the right-hand rope ~ and reduces that o~ the left-hand rope 9. The sagging o~ the right-hand rope 8 increases and that of the left-hand one 9 decreases with the result that the tilt of the side idlers 6 along the right-hand side o~ the belt in-25 creases whereas the side idlers 6 at the oppositeside o~ the belt incline to a le~ser degree. The belt responds by ceasing to displace sidewise and ~263~35 returnin~ into the ~lignment with the conveyor axis.
The linking means (tie rods) 13 c-an be con-nected to the ~rame 2 so as to turn about their a~-es throu~h a limited angle (Fi6. 4) in addition to 5 swinging in a plane at right angles to the axis of the conveyor. ~'he side idlers 6 are then in a position to tilt in the plane of the belt, whereby the fulcrum pins 11 will incline out of ~quare with the conveyor axis through a small angle defined by the tensioning o~ the wire ropes 8,9~ the extent within which the ~ulcrum pins 11 o~ the side idlers 6 are secured each to the wire ropes 8,9 and some other ~actors considered hereinafter.
Collisions of lump material with side idlers 6 in operation and the friction between the belt 1 and the side idlers 6 bring about a force ~2 which is applie~ to the idler 6 (Fig. 4). Since the tie rod 13 can turn about it~ axis, force F2 causes the idler 6 to incline in the plane of the ~elt as shov~n in Fi~s. 4 and ~ (the direction of belt travel is shown by arrows). In tilting, the idler 6 causes the respectiYe wire rope 8 or 9 to bend resiliently so that the tilt of the idler 6 appears to be propor-tional to the rorce F2 applied. In travelling past the side rollers 6 which are inclined as shown in Figs. 4 and 6, tne belt 1 gives rise to a ~orce equalling F2 in magnitude but opposing in direc-~26333~i tion. Denoted ~1' this ~orce is resolved into a~orce F3 resisting the revolution of the idlers 6 and an aligning Iorce F4 which causes the belt to displace towards the centre of tne conveyor. As long as the belt operates Deing aligned with the convey-or axis, the aligning ~orces F4 set up at left-hand side idlers 6 equal the lorces F4 at right-hand side idlers in magnitu~e out oppose them ln direction.
ShouLd ~ne belt 1 shift, for example, rightwards,the total impact load on, and the total resistance to the belt travel of, right-hand ~ide idlers 6 incre-ase and so does the tilt of these idlers, exceeding the tilt during the period oY belt alignment. At the ~ame time, the tilt o~ le~t-hand side idlers 6 de-creases because of the number of collisions withlump material and the resistance to belt travel de-creasing there. Since the sligning forces ~ are pro-portional to the tilt o~ side idlers 6 in the plane of the belt, they increase at t~e right-hand side idlers 6 and decrease at the left-hand side ~dlers 6.-~he aligning ~orces F4 at right-hand side idlers, towards which has displaced the belt 1, exceed the aligning forces at the left-hand side, and the re-sultant o~ these ~orces causes the belt to return into the alignment with the conveyor axis.
~ he fulcrum pins 11 of side idlers 6 should tilt in the plane of the belt through an angle (see Fig. 6 in whicn the tilted position o~ a sideidler is shown in dashed lines). '~'lithin the given ran~e of the values o~ the an~le ~ between 0 and

3, the aligning force F4 changes directly with tne 5 tilt of side idlers. ~he belt slides over side idl-ers 6 with some spring which reduces the wear on the belt due to contact with side idlers. A tilt of side idlers in excess o~ 3 brings about a constant belt~to-idler sliding contact which intensi~'ies belt 10 wear and causes the aligning ~orce to decrease.
~ 'he linkinD means (tie rods) 13 must be con-nected each to the respective ~ulcrum pin 11 of the side idler 6 so as to l'orm ~ith the pin an angle of substantially 10-65. ~he reason why the side idler 15 6 must make with the medial idler 5 an an~le ~ which is 65 or less (Fig. 5) is that the belt troughing set up du~ to this angle cannot be ~urther increased in most cases due to an inadequate resiLiehce of belt material. Stress concen~rations are produced 20 at bends wbich lead to rapid belt wear. ~oreover, an angle c~ which the tie rod 1~ makes with the ~ulcrum pin 11 o~ the side idler 6 also cannot exceed 65 because o~ the position o~ the pivot 14 which can-not be located below a plane throu~h the wire ropes.
25 At the same time, the angle c~ cannot be less than a certain minimum or otherwise the ability of side idler 6 to tilt in the plane of the belt will be im-~2633~;

peded. For e~ample, ~hen c~= 0, the side idler 6 cannot tilt ill ~he plane of the belt at all. ~he minimum an~le which enabl~s the side idler 6 to re-tain its ability to tilt is arou~d 10.
5 The fulcrum pins 11 of the side idlers 6 are con-nected to the tie rods 13 through longitudinal rests 15 (Figs. 3,4,7 and 8). The longitudinal rests 15 are secured to the wire ropes 8, 9 wit~ the aid of clamps 16. The length of every clamp 16 can eith-10 er equal that o~ the rest 15 (Figs. 3 and 4) or bea fraction of tne length of' the rest 15 (Figs. 7 and - 8). The fulcrum pins 11 of the side idlers 6 can make eac~ a ri~ht an~le with that portion of the rest 1~ which is linked to the wire ropes 8,9 thro-15 ugh the clamp 16. This arrangement eliminates the need to keep an eye on the perpendicularity of the ~ide idlers with respect to the wire ropes 8,9 in installing the conveyor. It also enables side idlers to tilt in the plane o~ the belt through a limited 20 angle in proportion to the Yorce Fl applied to side idlers (Fig. 4).
The clamps 16 can be provided in a ~orm per-mitting a relative displacement of the rests 15 --integrally with the tie rods 13 and folcrum pins 11 25 of the side idlers 6 -- and either of the two wire ropes 8 and 9 attached wher6to are the rests 15.
The pivots 14 must be provided in a ~orm permitting - 2~ -~26333S

each of the tie rods 1~ to turn about its axis thro-ugh a limited angle, to displace along its axis through a limited dista~ce and swing in a plane at right angles to the conveyor axis (the direction of 5 correspondin~ movements of components with respect to each other is shown by arrows in Fig. 7). This layout provides for controlling the position of the medial idlers 5 by varying the tension of tne wire ropes ~, 9 without changing the position o~ the side 10 idlers 6. ~or example, if the aligning e~fect of side idlers 6 is insu~ficient to correct a sidewise displacement of the belt 1, sa~ to the ri~ht, the position o~ ~he wire rope 8 relative to the ~rame is changed, i.e. the rope is moved rorlNard in the 15 direction of celt travel, with the aid of a tension-ing means 10 (~`ig. 1~ located on the right side.
~he displacement of the wire rope 8 causes the me-dial idlers 5 to turn counter-clockwise through an a~gle ~hich sets these idlers out-of-square with the 20 direction of travel of the belt 1. The angular dis-placement o~ the ~edial idlers 5 sets up a ~orce-which causes the belt 1 to reverse the direction of its sidewise displacement. This is the way an extra control o~ the position of the belt is excercised 25 when the conYeyor is in operation. The tensioning means 19 which are used to change the tension in, and the position of, the ~ire ropes 8,9 are locat-12~ 35 ed outside tnt frame 2 so as not to interfere with the operation of the belt! ~he side idlers remain in this case static and continue their belt-training ~ unction .
In another embodiment the way in which medial idlers 5 are adjusted for position, the rests 15 are rigidly attached to the wire ropes ~,9 at least wi-thin a portion of their en~th and the pivots 14 are provided each in a rorm permitting every tie rod 13 10 to displace alon~ its a~is and along the frame 2 and to turn about its axis tnrough a limited angle (pos-sible directions of motion of the tie rod 1~ are shown by arrows in ~ig. 8). The medial idlers 5 are adjusted ~or position in the same manner as in the 15 former embodiment but the side idlers 6 travel along the frame 2 when the wire ropes 8,9 are being pulled.
~ he ~ulcrum pins 11 of side idlers 6 and the tie rods 13 can be attached to opposite ends o~ the rests 15 so that the fulcrum pins 11 trail the tie 20 rods 13 in the direction o~ belt travel (Figs. 3,4, 7 and 8). ~his ~eatur~e oY the design sholtens the time la~ of the side iàlers 6 which tilt in the plane Or the belt. Also the tilting of side idlers in the opposite direction due to inaccuracies in 25 installin~ the conve~or or belt operation on inclin-es in loaded condition i~ prevented in this ease.
To simpli~y construction, the rests 15 can be made ..... .

1~335 integrally with tne tie rods 13.
The pivots 14 connecting the tie rods 13 to the ~rame 2 can be provided in a form permitting an adjustment of their position for hei~ht on the frame 2 (Fig. 8). ~l'his feature offers an extra may of con-trolling the an~le which the side idleIs 6 make with the a~es of the medial i~ler~ ~ ln tilting. As alre-ady pointed out, an increa~e in the tilt of side idlers is conducive to restoring correct belt train-ing and a decrease in the tilt ha~ an adverse effecton the stability of belt travel. h`or an accurate belt training in operation, the tilt of side idlers must be expertly increased at one or other side of the belt. This control can be exercised without stop-ping the conveyor.

.. . .

Claims (10)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:-

1. A belt conveyor comprising:
a sturdy framework extending along the axis of the conveyor; at least two lengthy pliable load-carrying members which run inside said framework substantially parallel to each other and to the axis of the conveyor and are linked to said framework 90 as to get support in a given position relative the-reto;
a means of tensioning said pliable load-carry-ing members inside said framework; a plurality of me-dial rolling means which are located between said pliable load-carrying members substantially at right angles thereto and are spaced a distance apart from each other over the full length thereof;
a plurality of fulcrum pins located substan-tially atr right angles to said pliable load-carrying members so that the supporting end of said fulcrum pins are connected to said pliable load-carrying members with provision for displacing integrally therewith in the vertical and horizontal planes;
a plurality of side rolling means which are fitted to said fulcrum pins on either side of said pliable load-carrying members outwards thereof and are spaced a distance apart from each other;
a plurality of linking means each whereof is rigidly attached to the respective said fulcrum pin of side rolling means with one end so as to make an angle therewith and is pivoted to said framework with the other end with provision for unobstructed swinging in a plane at right angles to the axis of the conveyor;
pivoting means which serve to connect the oth-er ends of said linking means to said framework al-ong the outward sides of said pliable load-carrying members substantially not below a plane therethro-ugh;
an endless conveyor belt receiving support from said medial rolling means and said side rolling means;
a drive of said conveyor belt.

2. A belt conveyor as claimed in claim 1, whe-rein said linking means are connected to said frame-work with provision for turning about their axes through a limited angle.

3. A belt conveyor as claimed in claim 1, wherein said linking means are connected to said framework with provision for turning about their ax-es through a limited angle so as to enable said ful-crum pins of side rolling means to tilt relative to said pliable load-carrying members in the direction of belt travel through an angle of 0-3° from the per-pendicular.

4. A belt conveyor as claimed in claim 1, whe-rein said linking means are connected to said ful-crum pins of side rolling means so as to make an angle of 10-65° therewith.

5. A belt conveyor as claimed in claim 1, wherein the supporting ends of said fulcrum pins of side rolling means are connected to said pliable load-carrying members through longitudinal rests which are secured to said pliable load-carrying me-ans at least within a portion of their length, whe-reby this portion of their length is located at right angles to said fulcrum pins of side rolling means.

6. A belt conveyor as claimed in claim 5, wherein said rests are connected to said pliable load-carrying members with provision for a longitu-dinal displacement of said pliable load-carrying members relative to said rests, whereby said linking means are connected to said framework with provision for displacing therealong and for turning about their axes through a limited angle so as to enable said fulcrum pins of side rolling means to tilt re-lative to said pliable load-carrying members in the direction of belt travel through an angle of 0-3°
from the perpendicular.

7. A belt conveyor as claimed in claims 5, wherein said rests are rigidly connected to said pliable load-carrying members so that said rigid connection is effected within at least a portion of the length of said rests, whereby said linking means are connected to said framework with provisi-on for displacing therealong and a limited displac-ing at right angles thereto and with provision for turning about their axes through a limited angle.

8. A belt conveyor as claimed in claim 7, wherein said fulcrum pins of side rolling means and said linking means are rigidly connected to said rests at opposite ends thereof so that said fulcrum pins of side rolling means trail said linking means in the direction of belt travel.

9. A belt conveyor as claimed in claim 8, wherein every said fulcrum pin of side rolling means forms with every said linking means and every said rest which are associated therewith a single unit.

10. A belt conveyor as claimed in claim 1, whe-rein the other ends of said linking means are con-nected to said framework with provision for adjust-ing their position in the vertical on said frame-work.