US3693781A

US3693781A - Training apparatus for driven belts

Info

Publication number: US3693781A
Application number: US113535A
Authority: US
Inventors: Ronald F Homeier
Original assignee: FMC Corp
Current assignee: FMC Corp
Priority date: 1971-02-08
Filing date: 1971-02-08
Publication date: 1972-09-26
Anticipated expiration: 1989-09-26
Also published as: BR7200511D0; CA958997A; ZA72379B

Abstract

An apparatus for training the carrying or return run of a conveyor belt supported on a plurality of spaced idler roller assemblies, includes a pair of rotatably mounted actuating rolls disposed adjacent the edges of the belt in a position to be contacted by the belt when the belt becomes off-centered. One end of a flexible shaft is operatively connected to each actuating roll to turn in unison therewith while the other end of the flexible shaft is operatively connected to the input shaft of a planetary gear reducing unit. The output shaft from the reducing unit is connected through bevel gears to a pivoting vertical shaft upon which an idler roller supporting frame is mounted. Pivotal movement of the supporting frame angularly displaces a belt supporting idler roller mounted thereon to urge the belt toward a centered position between the actuating rolls where it is out of contact with either roll. In an alternative embodiment the actuating rolls upon a predetermined pivotal movement, contact limit switches to actuate a reversible electric motor that drives the planetary gear reducing unit. The reducing unit is linked to an idler roller supporting frame just as in the first embodiment to pivot the idler roller about a vertical axis. Over-travel limit switches are also provided to shut the motor off in the event the supporting frame is pivoted to its pivotal limit.

Description

United States Patent Homeier Sept. 26, 1972 [54] TRAINING APPARATUS FOR DRIVEN BELTS [72] Inventor: Ronald F. Homeier, Plainfield, Ind. [73] Assignee: FMC Corporation, San Jose, Calif.

[22] Filed: Feb. 8, 1971 21 Appl. No.: 113,535

[52] US. Cl. ..198/202, 226/23, 226/45 Primary Examiner-Evon C. Blunk Assistant Examiner-Douglas D. Watts Att0rneyF. W. Anderson, C. E. Tripp and G. M. Po1umbus [57] ABSTRACT An apparatus for training the carrying or return run of a conveyor belt supported on a plurality of spaced idler roller assemblies, includes a pair of rotatably mounted actuating rolls disposed adjacent the edges of the belt in a position to be contacted by the belt when the belt becomes off-centered. One end of a flexible shaft is operatively connected to each actuating roll to turn in unison therewith while the other end of the flexible shaft is operatively connected to the input shaft of a planetary gear reducing unit. The output shaft from the reducing unit is connected through bevel gears to a pivoting vertical shaft upon which an idler roller supporting frame is mounted. Pivotal movement of the supporting frame angularly displaces a belt supporting idler roller mounted thereon to urge the belt toward a centered position between the actuating rolls where it is out of contact with either roll.

In an alternative embodiment the actuating rolls upon a predetermined pivotal movement, contact limit switches to actuate a reversible electric motor that drives the planetary gear reducing unit. The reducing unit is-linked to an idler roller supporting frame just as in the first embodiment to pivot the idler roller about a vertical axis. Over-travel limit switches are also provided to shut the motor off in the event the supporting frame is pivoted to its pivotal limit.

12 Claims, 10 Drawing Figures PATENTEflsiPzs I972 SHEET 5 BF 5 REVERSIBLE ELECTRIC MOTOR T'IG IEI 1 TRAINING APPARATUS FOR DRIVEN BELTS BACKGROUND OF THE INVENTION 1. Field of the Invention Conveyor belts are used to convey a variety of materials, some of which are quite heavy and difficult to load evenly on a belt. it is practically impossible to load a belt with this type of material so that the load is exactly centered on the belt. When the material on the belt is not centered, the uneven loading causes the belt to shift laterally to one side or the other of the support ing rollers necessitating frequent adjustments and more or less constant attention by the operators.

To alleviate the constant attention of the operators, automatic self-adjusting training devices have been developed. These devices, in very simplistic terms, sense lateral movement of the belt and respond by angularly displacing idler rollers overwhich the belt is traveling to urge the belt in the opposite lateral direction. v Y

2. Description of the Prior Art Conventional training devices for keeping a conveyor belt centered upon supporting idler rollers typically include an idler roller supporting frame member which is pivotallymounted upon a central vertical shaft. Secondary rollers are generally mounted adjacent the sides of the belt to sense lateral movement, and through appropriate linkages, effect rotation of the roller supporting frame member to urge the belt in the opposite lateral direction. Due to the type of linkages used in conventional training devices, the devices are not readily alterable to accommodate belts of varying widths and, therefore, require a separate unit for every width of belt utilized. Also, in conventional devices the secondary rollers create a drag on the sides of the belt causing undue wear and rapid deterioration of the belt. This is particularly true in the case of rigidly mounted secondary rollers wherein the frictional engagement forces of the belt against the rollers increases as the belt becomes more askew.

Typical of prior art belt training devices known to applicant are U.S. Pat; No. 1,770,957 issued to C. J. Veale on July 22, 1930, U.S. Pat. No. 2,488,859 issued to C. Y. Garber on Nov. 22, 1949, and U.S. Pat. No. 2,569,419 issued to M.A. Kendall on Sept. .25, 1951.

SUMMARY OF THE lNVENTlON The present invention concerns a powered belt training device for use in training carrying and return runs of a belt in a belt conveyor system. A plurality of the devices are used in a belt conveyor system each placed at pre-selected intervals along the run of the conveyor belt to correct any lateral movement of the belt and thereby assure a smooth and relatively straight movement. A smooth and straight belt movement is particularly important when carrying wet sticky materials that if spilled from the belt can cause damage to the conveyor system components.

The belt training device is designed to have sufficient training force and traction to train belts of any size that are exposed to severe misaligning and environmental conditions without exposing the surface or edges of the belt to damaging forces. In addition the device is easily adjusted to accommodate various sized belts with varying degrees of sensitivity.

In one embodiment, the belt training device of the present invention is entirely mechanical. It has a belt supporting training idler roller mounted upon a main frame member pivotal about a vertical axis and a belt powered training drive system for rotating the main frame member upon lateral movement of the belt. in this manner the belt supporting idler roller will be rotated a predetermined direction in a horizontal plane to urge the belt from its laterally shifted position to a centered position on the idler roller.

The belt powered training drive system includes a pair of actuating rolls disposed adjacent the sides of the belt in a position to be contacted and rotated by a laterally displaced moving belt, and a pair of flexible shafts operably connected to the actuating rolls to rotate in unison with the rolls. The flexible shafts operably link the actuating rolls to agear reducing unit of the drive system which is operably connected to the main frame member to effect pivotal movement of the member.

The rotatable actuating rolls are pivotally mounted on horizontal shafts lying parallel to the line of direction of the conveyor belt so that when the rolls are contacted by a laterally shifting belt, the'rolls will not only rotate to effect re-centering of the belt through the flexible shaft and the gear reduction unit, but will also pivot in a vertical plane in the direction of the lateral belt movement to avoid excessive frictional contact between the belt and the roll. The actuating rolls by pivoting laterally with the belt prevent excessive wear on the edges of the belt, which has inthe past been a prevalent problem with conveyor I belt training apparatuses.

The gear reducer is a high ratio unit and due to 'the large mechanical advantage offered provides a high training torque to the training rolls with a minimum of contact force of the belt against the actuating rolls. The gear reducer converts the relatively high speed but low torque rotation of the actuating rolls into a low speed and high torque rotational drive for the main frame supporting the training roller. The high ratio unit provides a stabilizing training force by alleviating over responses which tend to continually drive the belt back-and-forth in search of a stabilized and centered position.

An alternative embodiment of the invention is also disclosed wherein a reversible electric motor is used to drive, through a gear reducing unit, the rotatable main frame member which supports the training idler roller. In this embodiment actuating rolls areprovided alongside the conveyor belt, just as in the first embodiment, only rather than being linked to the gear reducing unit by a flexible shaft, electrical switches are provided whereby when an off centered belt has pivoted an actuating roll a predetermined lateral distance, the electric motor will be started to thereby rotate the training roll and drive the belt back to a centered position.

The gear reducing unit in the electrical embodiment is also a high ratio unit so that a stabilizing effect as in the first embodiment is attained. Over-travel limit switches are also provided so that the electric motor can be turned off in the event the main frame member reaches its travel limit.

For better training traction of the belt, in either embodiment, a slave training roller can be mechanically linked to the main frame member to pivot in unison therewith. The slave trainer provides additional contact surface thereby increasing training traction.

Accordingly, it is an object of the present invention to provide an improved apparatus for training conveyor belts.

It is another object to provide a belt training apparatus wherein actuating rolls adjacent the belt sides are pivotally mounted to reduce wear on the belt edges.

It is another object to provide a belt training apparatus wherein rotation of the actuating rolls are transmitted to a gear reducing unit through flexible shafting.

It is another object to provide a belt training apparatus that is readily alterable to accommodate belts of various widths.

It is still another object to provide a belt training apparatus wherein a high ratio gear reducer is used to convert high speed low torque rotation into low speed high torque rotation and transmit the rotative motion from the actuating rolls to the main frame member supporting the training roller. I

It is still another object to provide a belt training apparatus wherein a reversible electric motor is used to rotate the main frame member supporting the training idler roller.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an isometric view of one embodiment of the belt training apparatus as seen from'below the return run of an endless conveyor belt system. I

FIG. 2 is a front elevation of the training apparatus of FIG. 1 with parts broken away for clarity.

FIG. 3 is an enlarged longitudinal section of an actuatin g roll used in the training apparatus.

FIG. 4 is a sectional view taken along line 4-4 of FIG. 2. 1

FIG. 5' is a sectional view taken along line 5-5 of FIG. 4. t

FIG. 6 is a diagrammatic operational plan view of the training apparatus showing the training idler roller of the main frame and of the'slave trainer in an angularly displaced position for driving the conveyor belt back to a centered position.

FIG. 7 is an enlarged transverse section taken along line 7-7 of FIG. 6.

FIG. 8 is a front elevation of the training apparatus as used on the carrying run of an endless conveyor belt system. 7

FIG. 9 is an isometric view of a second embodiment ofthe belt training-apparatus as seen from below the return run of an endless conveyor belt system.

EIG. 10 is a schematic electric diagram of the control circuit fortheapparatus of FIG. 9.

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the training apparatus of the present invention is seen in FIGS. 1 to 7 and is generally designated 20. The apparatus consists of a stationary mounting structure 21, a pivotal main frame member 22 supported by the structure 21, a training idler roller 24 carried by the frame member 22, and a drive system generally designated 26 for pivoting the main frame member about a vertical axis.

Thestationary mounting structure 21 is supported adjacent a reference surface, such as the ground, by any suitable means (not shown). The mounting structure includes an angle iron base 28 with an upstanding ear 30 on either end. A bushing 32 (FIG. 2) extends vertically through the base 28 at a point midway between the ears 30 and serves as a guide for a vertical pivot shaft 34.

The pivotal main frame member 22 has an angle iron base 38 with an upstanding arm 40 rigidly secured to either end. The arms 40 serve to rotatably support the training idler roller 24 which is maintained in operative engagement with the underside of an endless conveyor belt 42. Extending longitudinally from either end of the base 38 are follower rollers 44 which restrict and guide the pivotal movement of the main frame by their disposition in slots 46 cut in the cars 30 of the mounting structure. The base 38 has a hub 48 fixedly mounted intermediate the arms 40 to receive the upper end of the pivot shaft 34. The pivot shaft is keyed to the hub at 50 so that the main frame member will pivot in unison with the pivot shaft thereby enabling relative pivotal movement between the main frame member 22 and the mounting structure 21.

The drive system 26 for the training apparatus is composed of a pair of actuating rolls 52 and 54, a gear reduction unit 56, and flexibleshafts 58 and 60 for operably connecting the respect actuating rolls to the gear reduction unit.

The actuating rolls 52 and 54 are pivotally mounted adjacent the lateral edges of the conveyor belt 42 on substantially F-shaped

brackets

62 and 64 respectively. The

brackets

62 and 64 are welded or otherwise secured to the upstanding cars 30 of the mounting structure 21 and have inwardly projecting fingers-66 for supporting the actuating rolls. As best seen in FIG.

I the fingers66 have a plurality of aligned pairs of ap'ertures 68 for removably receiving a shaft 70 upon which an actuating roll is pivotally mounted. The shaft can be readily moved from one pair of apertures to another to adjust the lateral displacement of the actuating rolls. By adjusting the lateral displacement of the actuating rolls, the apparatus can be adapted to accommodate various sized conveyor belts. In addition the lateral displacement of the actuating rolls can be varied to obtain a desired spacing between the actuating rolls and the lateral edges of the conveyor belt to regulate the sensitivity of the apparatus in a manner which will become apparent with the description that follows.

Actuating roll 52 is best seen in FIG. 3, it being understood that actuating roll 54 is structurally identical. The actuating roll has a center shaft 72 onto one end of which is welded a steel roll 74. A thick-walled cylindrical tire 76 is pressed onto the steel roll so that there is no relative movement between the tire and the roll. The tire is disclosed as being made of rubber, however, any suitable material that has a relatively high coefficient of friction, is durable and will not cause undue wear of the conveyor belt may be used. A cylindrical bearing sleeve 78 is mounted on the central portion of shaft 72 by ball bearings 80 so that the shaft is free to rotate relative to the sleeve 78. A cylindrical counterweight 82 having a central longitudinal bore is snuggly fitted against the inner wall of the bearing sleeve so that its position can be longitudinally adjusted within the bearing sleeve. The diameter of the bore is greater than the diameter of the central shaft 72 thereby preventing any frictional contact between the two concentric members.

A bushing sleeve 84 is welded to the outer wall of the bearing sleeve 78 so that the longitudinal axes of the respective sleeves lie perpendicular to each other. Bushings 86, only one being shown, of any suitable material are fitted into the ends of the bushing sleeve to provide a low-friction interface between the bushing sleeve and the shaft 70 which lies within the sleeve to pivotally mount the roller 52 on the bracket 62.

The end of the center shaft 72 opposite that which has the roll 74 has a reduced longitudinal extension 88 which fits into a mating longitudinal bore in one end of a substantially cylindrical connector 90 and is secured to the connector by a set screw 92. The opposite end of the connector has a similar longitudinal bore for receiving one end of a metallic cable 94, which along with a sheath 96 comprises the flexible shaft 58 of the drive system. The cable may be made of anysuitable material that is flexible and capable of transmitting rotative motion with the required torque. For purposes of disclosure, however, the cables disclosed in the present embodiment are conventional speedometer cables which have been found to give entirely satisfactory results. The cable 94 is secured to the connector. by a set screw 98 so that the cable will rotate in unison with the center shaft 72 and the tire 76. A non-rotatable protector sleeve 100 and boot 102 are provided at the connector end of the actuating roll to prevent the ingress of damaging particles.

Attached to the underside of the mounting structure 21 is an inverted U-shaped bracket 104 with

side walls

106 and 108 for housing a reversing gear unit 110. The reversing gear unit contains two identical gear wheels 112 and 114 (FIG. 5) which are operably connected to corresponding ends of the

flexible shafts

58 and 60 respectively.

Gear wheel 1 12 is secured by a set screw between the

side walls

106 and 108 to an input shaft 116 of the gear reduction unit 56. The input shaft 116 extends rotatably through side wall 106 and has a reduced end portion that extends rotatably through side wall 108. The reduced endportion has a tip 118 which is square in cross-section and which fits into a mating cubical cavity in a cap 120 that is fixedly secured to an end of cable 94. The cap 120 is held in mating engagement with the tip 118 by an annular shoulder oh the cap that abuts against the end of a collar 122 fixedly secured to the sheath 96 of the flexible shaft 58. The collar 122 is in turn held adjacent the tip 118 of input shaft 116 by abutment of a shoulder on the collar against a cupshaped bracket 124 fixedly secured to side wall 108 by screws 126.

Gear wheel 114 is secured by a set screw between

side walls

106 and 108 to an auxiliary shaft 128 which is rotatably mounted in the side walls. Auxiliary shaft 128 is mounted in parallel relationship to input shaft 116 and is displaced therefrom a distance such that the reversing

gear wheels

112 and 114 are intermeshed. The auxiliary shaft has a reduced diameter extension 130 which extends outwardly from side wall 106 and has a tip 132 which is square in cross-section. The auxiliary shaft is connected to the flexible shaft 60 in a manner identical to that in which input shaft 116 of the gear reduction unit is connected to flexible shaft 58.

It is apparent from the above description that rotation of actuating roll 52 will cause rotation of flexible shaft 58 and consequently an associated rotation of input shaft 116 and gear wheel 112. Due to the intermeshing of

gear wheels

112 and 114, this same rotation of actuating roll 52 will cause an equivalent rotation of gear wheel 114, auxiliary shaft 128, flexible shaft 60 and actuating roll 54. Thus, when viewed in top plan as in FIG. 6, counterclockwise rotation of actuating roll 52, as indicated by arrow A1, will effect counterclockwise rotation of actuating roll 54, as indicated by arrow A2. However, inasmuch as only one of the actuating rolls 52 and 54 can be in contact with the conveyor belt at any one time, the rotation of the un-contacted actuating roll in a direction counter to the direction of the belt movement will have no undesirable effect. It is readily seen then that if the conveyor belt is in contact with actuating roll 52, as in FIG. 6, imparting counterclockwise rotation to the actuating roll 52, input shaft 116 of the gear reduction unit will'also be caused to be rotated in a counterclockwise direction as viewed in FIG. 4 and as indicated by arrow A3. On the contrary, if the conveyor belt is in contact with actuating roll 54 imparting clockwise rotation (see arrow B1) to the actuating roll 54 as viewed in FIG. 6, and clockwise rotation to the uncontacted actuating roll 52 (arrow B2), then the reversing gear unit will effect clockwise rotation of input shaft 116 (arrow B3) of the gear reduction unit.

The gear reduction unit 56 is a conventional device employing planetary gears to develop a high ratio gear reduction. In the above described embodiment of the invention a reduction of 952:1 is achieved'with a Series l-I-I horizontal planetary reducer manufactured by the Winsmith Division of UMC Industries, Inc., Springville, New York; however, any reducing unit could be used which attains a comparable reduction of rotational speed. It is thus apparent that the gear reduction unit 56 will convert a high speed low torque input to shaft 116 into a relatively'low speed high torque output. An horizontal output shaft 134 of the gear reduction unit will, therefore, be rotated very slowly if the conveyor contacts an actuating roll imparting relatively high speed rotative motion to the actuating roll.

The horizontal output shaft 134 of the gear reduction unit has a bevel gear 136 fixedly secured on its outer end. The bevel gear 136 is disposed in meshing engagement with a bevel gear 138 fixedly secured to the lower end of the pivot shaft 34 so that rotary motion of the horizontal output shaft 134 will impart rotary motion to the vertical pivot shaft 34. As mentioned hereinbefore, the pivot shaft is keyed at 50 to the main frame member 38 whereby any pivotal motion of the pivot shaft will cause pivotal movement of the main frame member. It is also important to note that the meshing

bevel gears

136 and 138 are oriented so that when actuating roll 52 is contacted by the moving conveyor belt 42 causing the actuating roll to rotate in a counterclockwise direction as viewed in FIG. 6, the main frame member 38 will rotate in a clockwise direction, as indicated by arrows A4, to urge the belt away from the actuating roll 52 to a centered position between the actuating rolls 52 and 54. Conversely, when the belt contacts actuating roll 54 causing it to rotate clockwise as viewed in FIG. 6, the main frame member 38 will rotate in a counterclockwise direction (see arrows B4) to urge the belt away from the actuating roll 54 to a centered position between the actuating rolls.

An important aspect of the present invention is the manner in which the actuating rolls are constructed and mounted on the mounting structure 21 to avoid undue pressure on the conveyor belt when the belt becomes askew and contacts one of the actuating rolls. It can be seen in FIGS. 2 and7 that the actuating rolls are pivotally mounted at an acute angle to. the conveyor belt and primarily below the belt so that only the lowermost portion of a lateral edge of the belt contacts the actuating roll. The inclined disposition of the actuating rolls is attained by sliding the counterweight 82 within the bearing sleeve 78 of the actuating rolls to a longitudinal position wherein the actuation rolls become top heavy and tilt away from the vertical. The longitudinal position of the counterweight also determines the force with which theactuating rolls will pivotally resist the lateral movement of the belt. his not important that the actuating rolls present a great resistive force, in fact, it is highly desirable that the resistive force by only sufficient enough to provide the frictional force necessary to impart rotary motion to the actuating rolls. Any greater resistive force would produce undue wear of the conveyor belt. Thus, the angular disposition of the actuating rolls, the pivotal mounting, and the fact that the resistive force presented by the actuating rolls to lateral movement of the conveyor belt is adjustable, all cooperate to provide an arrangement for sensing lateral movement of the belt wherein the least amount of wear of the belt is produced.

' To increase the training effectiveness of the apparatus, a slave trainer 140 (FIG. 1) can be operably linked to the main frame member 22 of the main training apparatus 20. The slave trainer provides additional belt contacting surface to increase training traction. It will-be observed that the slave trainer is substantially similar to the main training apparatus only it does not have an independent drive system.

The slave trainer has a stationary mounting structure 142 supported adjacent a reference surface, such as the ground, by any suitable means (not shown). The mounting structure has an angle iron base 144 with an upstanding car 146 on either end. A bushing 148 extends vertically through the base 144 at a point midway between the ears 146 and serves as a guide for a vertical pivot shaft 150. A pivotal frame 152 having an angle iron base 154 with an upstanding arm 156 on either end (only one being shown) has a hub 158 at its longitudinal center which is keyed to the pivot shaft 150 enabling the frame 152 to pivot with respect to the mounting structure 142 about a vertical axis. Rollers 159 rotatably supported on the outer ends of the pivotal frame and riding in slots 160 in the ears 146, guide thepivotal movement of the frame. The arms 156 rotatably support a belt engaging idler roller 161. A rigid linking arm 162 is pivotally secured at one end to the pivotal frame 152 of the slave trainer and at its other end to main frame member 22 of the main training apparatus 20. The pivotal connections of the linking arm 162 to the respective frame members are adjacent associated ends of the frame members so that when main frame 22 is pivoted by the drive system 26, the pivot frame 152 of the slave trainer will be pivoted an equivalent amount in the same angular direction. Thus, it can be seen that the slave trainer works in unison with the main training apparatus 20 to provide additional controlled training traction when necessary, it being understood that all installations utilizing the present invention might not need the additional training force and, therefore, the slave trainer might be unnecessary.

A clear understanding of the operation of the training apparatus along with the slave trainer is facilitated by reference to FIGS. 6 and 7 wherein the conveyor belt 42, moving from right to left as viewed in FIG. 6, is shown in phantom lines in its centered position and in solid lines in a laterally shifted position in contact with actuating roll 52. It will be observed that actuating roll 52 is being rotated by the belt in a counterclockwise direction (as indicated by arrow Al) thereby causing the idler roller 24 of the main training apparatus and the idler roller 161 of the slave trainer to rotatein a clockwise direction (see arrow A4). The clockwise rotation of the-respective idler rollers urges the belt from right to left, as viewed in FIG. 7, toward a centered position between the actuating rolls 5,2 and 54.

FIG. 8 shows the training apparatus when adapted for the carrying run of the conveyor belt wherein there are three training idler rollers pivotally mounted on a curved axle 152 to define a trough-shaped support for the conveyor belt 42. The main difference in this adaptation of the training apparatus and that of the return run previously described is an altered main frame member 154 which is structurally different to accommodate the three training idler rollers. Also, the actuating rolls 156 and 158 are elevated to be adjacent the raised lateral edges of the conveyor belt. Otherwise the apparatuses are identical. There being no dif-' fere'nce in function,a detailed explanation of this adaptation is not felt necessary.

A second embodiment of the present invention wherein electrical energy is utilized to pivot the training idler roller is shown in FIGS. 9 and 10. The training apparatus is shown in FIG. 9 with the return run of the conveyor belt, it being understood that a similar apparatus would be used for the carrying run. With reference to FIG. 9 it can be seen that this embodiment of the training apparatus designated 200 includes a main mounting structure 202 having an upstanding ear 204 on either end with brackets 206 for pivotally mounting actuating rolls 208 and 210. The brackets 206 are substantially similar to

brackets

62 and 64 of the first described embodiment in that they have inwardly projecting fingers 212 with aligned pairs of apertures 214 for removably receiving a shaft upon which actuating rolls 218 and 220 are pivotally mounted. As in the first described embodiment the pairs of apertures 21'4 allow the actuating rolls to be mounted in the brackets at varied laterally displaced distances from each other and from the lateral edges of the conveyor belt 222.

A pivotal frame member 224 having an upstanding arm 226 on either end (only one being shown) is keyed to a vertical pivot shaft 228 for unitary pivotal movement therewith. The shaft passes rotatably through a bushing 230 at the longitudinal center of the mounting structure 202 and has a bevel gear 232 fixedly secured to its lower end. The arms 226 serve to rotatably support a training idler roller 234 so that the roller is free to pivot with the pivotal frame member 224 relative to the mounting structure 202.

The actuating rolls 208 and 210 are similar to the actuating rolls 52 and 54 of the previously described embodiment in that they are counterweighted and have a tire 236 rotatably disposed about a pivotally mounted shaft, however, the pivotal mounting of the shaft on the brackets 206 is slightly different and there are no flexible cables secured to the shaft to link the actuating rolls to a gear reducing unit. T

ln place of the flexible cable a reversible electric motor 238 is provided. The electric motor has an output shaft that is common with an input shaft of a gear reduction unit 240. The disclosed gear reduction unit is a Series l-I-I gear reducer as manufactured by the Winsmith Division of UMC Industries, Inc. With 3% H1. electric motor havinga 1,750 r.p.m. output, a reduction ratio of 5,400:1 was found to give a desirable result. The reduction ratio is entirely dependent on the speed of the electric motor, however, so applicant does not wish to be limited to any particular reduction ratio or any particular motor speed.

The actuating rolls 208 and 210 have a bearing sleeve 242 identical to the bearing sleeve 78 of the actuating rolls 52 and 54. A pivot shaft 244, having 'a trigger finger 246 secured radially to one end, isrigidly secured to the bearing sleeve 242 so that the longitudinal axes of the pivot shaft and bearing sleeve lie normal to eachother. The pivot shafts 244 are pivotally mounted in each bracket 206 so as to lie parallel to the longitudinal direction of movement of the conveyor belt whereby lateral movement of the belt will cause the belt to contact an actuating roll and pivot the roll and the shaft 244.

Mounted on one finger 212 of each of the brackets 206 are limit switches lLS and 2LS. The limit switches are disposed so that they can be operated and released by the trigger finger 246 on the ends of pivot shafts 244. When the actuating rolls are in their normally disposed position out of contact with the belt, the trigger fingers on the shafts 244 hold the switches lLS and 2L8 in an operated state wherein the electric motor is prevented from operating. When the switches are released, as when an actuating roll is pivoted by the belt causing a trigger finger 246 to move out of contact with its associated limit switch, the reversible electric motor 238 is energized driving the gear reduction unit 240 and consequently the pivotal frame 224 in one direction or the other dependent on which of the switches lLS or 2LS was released. Thus, release of a limit switch lLS or 2LS effected by the belt shifting laterally into contact with one of the actuating rolls, will cause the training idler roller 234 td pivot in one pre-determined angular direction or the other, urging the belt to move in an associated lateral direction back toward a centered position between the actuating rolls.

I when the pivotal frame reaches its pre-selected travel To prevent the training idler roller from pivoting exlimit in one direction it will operate limit switch 3LS and when it reaches its limit in the other direction it will operate limit switch 4LS. Limit switch 3LS and 4LS function to de-energize motor 238 thus preventing the pivot frame 224 from pivoting any further. It is possible also to connect the limit switches 3LS and 4LS to the motor drive (not shown) for the conveyor belt to thereby stop the belt whenever the training idler roller has been pivoted to its travel limit. An operator could then be summoned as by an alarm or other similar means, to redistribute the load on the belt or do whatever was necessary to rectify the situation.

It is apparent that the training traction of the apparatus could be increased by the inclusion of a slave trainer. Inasmuch as the slave trainer is totally dependent in operation on the main training apparatus, the slave trainer could be identical to the slave trainer of the first described embodiment so that it pivots in unison with the main training apparatus 200.

A schematic electrical diagram of the control circuit for the training apparatus is shown in F 16.. 10 with solid lines designating the condition of the switches lLS and 2LS when the switches are operated, that is, when neither actuating roll is being contacted by the belt and when the over-travel limit switches 3L8 and 4LS are in an unoperated, or released state. The reversible electric motor 238 is seen to have four terminals, T1 and T2 being field terminals and T3 and %4 being rotor terminals. According to fundamental electrical principles, the direction of rotation of the output shaft of an electric motor as shown can be changed by reversing the polarity of the field terminals. It will thus be seen from the following description of the circuit that when limit switch lLS is released, the motor will run in one direction and when limit switch 2L8 is released it will run in the other direction.

One terminal T5 of a l 10 volt AC power supply PS is connected to the over-travel limit switch 3L5, the overtravel limit switch 4LS, a contact lLS-la of limit switch lLS, and a contact 2LS-2a of limit switch 2LS. The other terminal T6 of thepower supply PS is connected to terminal T4 of the reversible motor 238, a contact lLS2c of limit switch lLS, and a contact 2LS-1c of limit switch 2LS. Therefore, when the limit switches are in the solid line positions of FIG. 10, it is seen that the terminals T1, T2 and T4 of the motor will be connected to power supply terminal T6, and terminal T3 will be disconnected from the power supply. With one terminal of the motor disconnected, the motor is incapable of running, so the pivotal frame 224 supporting the training idler roller will remain motionless under these conditions.

If the belt shifts laterally contacting actuating roll 208 causing it to pivot clockwise with the shaft 244 associated therewith, the trigger finger 246 on the associated shaft will pivot clockwise as viewed in FIG. 9 releasing limit switch lLS and leaving it in the dotted line condition of FIG. 10 wherein contacts lLS-la and lLS-2a are connected to contacts lLS-lb and lLS-2b respectively. In this condition and with the remaining switches in their solid line conditions, motor terminals T1 and T3 will be connected to power supply terminal T5 and motor terminals T2 and T4 will be connected to power supply terminal T6, thus energizing the motor to pivot the pivotal frame in a counterclockwise direction as viewed in FIG. 9. The belt will then be urged away from actuating roll 208 toward a centered position between the actuating rolls. As the belt loses contact with actuating roll 208, the associated trigger finger 246 again operates limit switch 11.8 to return it to the solid line condition of FIG. with contacts lLS-la and lLS-2a connected to contacts lLS-lc and lLS-2c respectively whereby, as described above, the motor is de-energized.

If the belt shifts laterally in the direction of actuating roll 210 and contacts the roll pivoting it in a counterclockwise direction with the associated shaft 244 and trigger finger 246, limit switch 2LS will be released to assume the dotted line condition of FIG. 10 with contacts 2LS-la and 2LS-2a connected to contacts 2LS-1b and 2LS-2b respectively. In this'condition it can be seen that motor terminals T1 and T4 will be connected to power supply terminal T6, and motor terminals T2 and T3 will be connected to power supply terminal T5. The field terminals TI and T2 are thus connected to opposite power supply terminals from when switch lLS was released, thereby energizing the motor to drive the pivot frame 224 in the opposite or a clockwise direction to urge the belt back to a centered position. As the belt loses contact with actuating roll 210, the associated trigger finger 246 again operates limit switch 2LS to return it to its solid line condition with contacts 2LS-la and 2LS-2a connected to contacts 2LS-lc and 2LS-2c respectively.

If the pivotal frame 224 is driven in a clockwise direction to its predetermined travel limit it will contact and operate limit switch 4LS thereby opening the switch contacts so that no current can pass therethrough. Moreover, in order that the pivotal frame be driven into operating contact with over-travel limit switch 4LS, limit switch 2LS must be released in its dotted line condition. With switch 2L8 released and switch 4LS operated, terminal T2 of the motor is disconnected from the power supply so that it is incapable of running. Therefore, if the pivotal frame is driven to its travel limit in the clockwise direction the motor will not run thus preventing any further pivotal movement of the frame.

In a similar manner if the belt is in contact with actuating roll 208 having pivoted the roll to release limit switch lLS and the pivotal frame 224 has reached its predetermined travel limit, over-travel limit switch 3LS will be operated and the contacts thereof opened. Inasmuch as limit switch lLS is in its dotted line condition under these circumstances, it can be seen that terminal T1 of the motor will be disconnected from the power supply, thereby preventing the motor from running. Therefore, the counterclockwise pivotal movement of the frame 224 will be terminated.

In view of the physical attributes of the training apparatus, it is evident that both actuating rolls could not be contacted by the belt at the same time. However, in rare instances depending on the type of material carried by the belt, a build-up of material on an edge of the belt occurs. In this instance it is conceivable that the belt might contact one actuating roll while the built up material contacted the other actuatingroll causing both limit switches lLS and 2L8 to be released simultaneously. Upon such an occurrence it can be seen that terminals T1, T2, and T3 of the motor will be connected to power supply terminal positively charged and terminal T4 will be negatively charged. The field terminals T1 and T2 having the same polarity, the motor would not run.

As was pointed out above, it is contemplated that an alarm could be included in the circuit whereby when the motor was shut down by either over-travel limit switch 3LS or 4LS or by both limit switches lLS and 21.8 being released at the same time, an operator would be alerted to rectify the problem.

It is to be understood that in either embodiment of the present invention, a plurality of training apparatuses would be disposed at preselected intervals along the entire length of both the carrying and return runs of the conveyor belt. In this manner any lateral deviation of the belt from its centered position can be quickly correctedat any location along the full run of the belt thereby assuring a smooth and straight movement.

Although the best mode contemplated for carrying .out the present invention has been herein shown and described, it will be apparent that modification and variation may be made without departing from what is regarded to be the subject matter of the invention.

I claim:

1. In a conveyor system having a pivotal main frame member mounted rigidly upon a vertical shaft, at least one roller supported by the main rotatable frame member, a moving endless conveyor belt partially supported by said roller, a rigid frame member, and first and second actuating roll assemblies mounted on the rigid frame member adjacent the side edges of the conveyor belt, said roll assemblies consisting of roll members rotatably mounted on shafts which are tiltable toward and away from the conveyor belt, the improve ment comprising a planetary gear reduction unit having input and output shafts, first and second flexible shafts operably connecting the respective actuating rolls to the input shaft of the reduction unit for transmitting rotary motion from the actuating rolls to the input shaft,

and means connecting the output shaft of the reduction unit to the vertical shaft supporting the pivotal main frame member so that low speed rotary motion of the output shaft will impart rotary motion to the said vertical shaft to rotate the pivotal main frame member under high torque and thereby urge movement of the belt in a lateral direction.

2. In a conveyor system having a pivotal main frame member rigidly mounted upon a vertical shaft, at least one roller supported by the main rotatable frame member, a moving endless conveyor belt partially supported by said roller, a rigid stationary frame member, and first and second actuating roll assemblies mounted on the rigid frame member adjacent the side edges of the conveyor belt, said roll assemblies consisting of roll members rotatably mounted on the shafts which are tiltable toward and away from the conveyor belt, the improvement comprising a gear reduction unit having input and output shafts, first and second flexible shafts operably connecting the respective actuating rolls to the input shaft of the gear reduction unit for transmitting rotary motion from the actuating rolls to the input shaft, said first flexible shaft fixedly secured to said input shaft, a first gear wheel rigidly affixed to said input shaft for unitary rotation therewith and with said first flexible shaft, a second gear wheel meshing with said first gear wheel and mounted for unitary rotation with said second flexible shaft, and means connecting the output shaft of the gear reduction unit to the vertical shaft supporting the pivotal main frame member so that rotary motion of the output shaft will impart rotary motion to the said vertical shaft to rotate the pivotal main frame member and thereby urge movement of the belt in a lateral direction.

3. The system of claim 2 wherein said actuating roll assemblies are adjustably counterbalanced.

4. The system of claim 2 wherein said actuating roll assemblies normally assume an orientation leaning outwardly from the conveyor belt.

5. The system of claim 2 wherein said rigid frame member has means for mounting the said actuating roll assemblies in any one of a plurality of positions to vary the horizontal spacing between saidassemblies.

6. The system of claim 2 further including a second rotatable roller supporting frame member operably linked to said-main rotatable frame member for corresponding movement therewith.

7. In a belt conveyor system having a pivotal main frame member rigidly mounted upon a vertical shaft, at least one roller supported by the main frame member, a moving endless conveyor belt partially supported by said roller, a stationary rigid frame member rotatably supporting the vertical shaft, and a pair of actuating roll assemblies mounted on the stationary frame member adjacent the side edges of the conveyor belt, the improvement comprising each actuating roll assembly having a roll member rotatably mounted on a shaft, each of said actuating roll assemblies being tiltable toward and away from the conveyor belt in the mounting of the roll assemblies on the stationary frame member, a counterweight adjustably mounted on each actuating roll assembly, a high ratio planetary gear reduction unit having an input and an output shaft, said reduction unit supported from the stationary frame member, means connecting each of the actuating roll shafts to the input of said gear reduction unit, and means connecting said output shaft of the gear reduction unit to the vertical shaft supporting the pivotal frame member so that the low speed rotary motion of the output shaft will impart rotary motion to the vertical shaft to rotate the pivotal main frame member under high torque and thereby urge movement of the belt in a lateral direction.

8. In a belt conveyor system having a pivotal main frame member rigidly mounted upon a vertical shaft, at least one roller supported by the pivotal main frame member, a moving endless conveyor belt partially supported by said roller, a stationary rigid frame member, and first and second actuating roll assemblies mounted on the rigid frame member adjacent the side edges of the conveyor belt, the improvement comprising each of said actuating roll assemblies being adjustably counterbalanced and tiltable toward and away from the conveyor belt in the mounting of the actuating roll assembly on the stationary frame member, a high ratio planetary gear reduction unit having an input and output shaft, a reversible electric motor operably connected to said input shaft, switches electrically conn cted to sad reversible lectric factor and isposed a acent Sal actuating rol assemb res so as to e actuated and released upon tilting movement of the roll assemblies to then operate said reversible motor, and means connecting the output shaft of the gear reduction unit to the vertical shaft supporting the pivotal main frame member so that the low speed rotary motion of the output shaft will impart rotary motion to the vertical shaft to rotate the pivotal main frame member under high torque and thereby urge movement of the belt in a lateral direction.

9. The system of claim 8 further including limit switches electrically connected to said reversible motor and disposed so as to be operated upon a predetermined rotary movement of said pivotal main frame member.

10. The system of claim 8 further including a second rotatable roller supporting frame member operably linked to said pivotal main frame member for corresponding movement therewith. I

'11. In a training idler adapted for use with a driven endlessbelt in a belt conveyor system including a pivotal main frame member rigidly mounted upon a vertical shaft, at least one roller supported by the pivotal main frame member, the roller partially supporting the belt, a fixed frame member rotatably supporting the vertical shaft, the improvement comprising a pair of actuating roll assemblies pivotally mounted on the outer ends of the fixed frame memberadjacent but normally spaced from the lateral edges of the driven belt, an adjustable counterweight within each of said pivoted actuating roll assemblies to maintain minimum frictional contact of the actuating rolls with the belt sufficient to rotate said actuating roll assemblies, a flexible shaft connected to each of said actuating roll assemblies and to be driven thereby, a planetary gear reduction unit having an input and an output shaft, reversing gear means operatively connecting said input shaft to each of said flexible shafts and said output shaft being operatively connected to said vertical shaft of the pivotal main frame member, whereby when the belt shifts transversely to contact one of the actuating roll assemblies, one of the rotating roll assemblies drives one of the flexible shafts and rotates the input shaft of the gear reduction unit whose output shaft then rotates at a much reduced speed to provide high torque pivotal movement of the main frame member and to thereby urge the belt to its centered position.

12. The training idler of claim 11 further comprising a second pivotal main frame member mounted on a vertical shaft, a fixed frame member rotatably supporting the vertical shaft, and at least one roller supported in said second pivotal main frame member, said second pivotal main frame member operably linked to said pivotal main frame member in tandem relation for corresponding pivotal movement therewith to provide greater traction in training the conveyor belt upon rotation of one of the actuating roll assemblies when the belt is displaced from its centered position.

Claims

1. In a conveyor system having a pivotal main frame member mounted rigidly upon a vertical shaft, at least one roller supported by the main rotatable frame member, a moving endless conveyor belt partially supported by said roller, a rigid frame member, and first and second actuating roll assemblies mounted on the rigid frame member adjacent the side edges of the conveyor belt, said roll assemblies consisting of roll members rotatably mounted on shafts which are tiltable toward and away from the conveyor belt, the improvement comprising a planetary gear reduction unit having input and output shafts, first and second flexible shafts operably connecting the respective actuating rolls to the input shaft of the reduction unit for transmitting rotary motion from the actuating rolls to the input shaft, and means connecting the output shaft of the reduction unit to the vertical shaft supporting the pivotal main frame member so that low speed rotary motion of the output shaft will impart rotary motion to the said vertical shaft to rotate the pivotal main frame member under high torque and thereby urge movement of the belt in a lateral direction.

5. The system of claim 2 wherein said rigid frame member has means for mounting the said actuating roll assemblies in any one of a plurality of positions to vary the horizontal spacing between said assemblies.

6. The system of claim 2 further including a second rotatable roller supporting frame member operably linked to said main rotatable frame member for corresponding movement therewith.

8. In a belt conveyor system having a pivotal main frame member rigidly mounted upon a vertical shaft, at least one roller supported by the pivotal main frame member, a moving endless conveyor belt partially supported by said roller, a stationary rigid frame member, and first and second actuating roll assemblies mounted on the rigid frame member adjacent the side edges of the conveyor belt, the improvement comprising each of said actuating roll assemblies being adjustably counterbalanced and tiltable toward and away from the conveyor belt in the mounting of the actuating roll assembly on the stationary frame member, a high ratio planetary gear reduction unit having an input and output shaft, a reversible electric motor operably connected to said input shaft, switches electrically connected to said reversible electric motor and disposed adjacent said actuating roll assemblies so as to be actuated and released upon tilting movement of the roll assemblies to then operate said reversible motor, and means connecting the output shaft of the gear reduction unit to the vertical shaft supporting the pivotal main frame member so that the low speed rotary motion of the output shaft will impart rotary motion to the vertical shaft to rotate the pivotal main frame member under high torque and thereby urge movement of the belt in a lateral direction.

10. The system of claim 8 further including a second rotatable roller supporting frame member operably linked to said pivotal main frame member for corresponding movement therewith.

11. In a training idler adapted for use with a driven endless belt in a belt conveyor system including a pivotal main frame member rigidly mounted upon a vertical shaft, at least one roller supported by the pivotal main frame member, the roller partially supporting the belt, a fixed frame member rotatably supporting the vertical shaft, the improvement comprising a pair of actuating roll assemblies pivotally mounted on the outer ends of the fixed frame member adjacent but normally spaced from the lateral edges of the driven belt, an adjustable counterweight within each of said pivoted actuating roll assemblies to maintain minimum frictional contact of the actuating rolls with the belt sufficient to rotate said actuating roll assemblies, a flexible shaft connected to each of said actuating roll assemblies and to be driven thereby, a planetary gear reduction unit having an input and an output shaft, reversing gear means operatively connecting said input shaft to each of said flexible shafts and said output shaft being operatively connected to said vertical shaft of the pivotal main frame member, whereby when the belt shifts transversely to contact one of the actuating roll assemblies, one of the rotating roll assemblies drives one of the flexible shafts and rotates the input shaft of the gear reduction unit whose output shaft then rotates at a much reduced speed to provide high torque pivotal movement of the main frame member and to thereby urge the belt to its centered position.