CA2229443A1 - Ac torque vector winch - Google Patents
Ac torque vector winch Download PDFInfo
- Publication number
- CA2229443A1 CA2229443A1 CA 2229443 CA2229443A CA2229443A1 CA 2229443 A1 CA2229443 A1 CA 2229443A1 CA 2229443 CA2229443 CA 2229443 CA 2229443 A CA2229443 A CA 2229443A CA 2229443 A1 CA2229443 A1 CA 2229443A1
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- Canada
- Prior art keywords
- secured
- input
- conveyor belt
- winch
- tensioning assembly
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65G—TRANSPORT OR STORAGE DEVICES, e.g. CONVEYORS FOR LOADING OR TIPPING, SHOP CONVEYOR SYSTEMS OR PNEUMATIC TUBE CONVEYORS
- B65G23/00—Driving gear for endless conveyors; Belt- or chain-tensioning arrangements
- B65G23/44—Belt or chain tensioning arrangements
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Devices For Conveying Motion By Means Of Endless Flexible Members (AREA)
- Drives For Endless Conveyors (AREA)
- Control Of Conveyors (AREA)
Abstract
A conveyor belt tensioning assembly (10) having a winch drum (14) and a pair of ac torque vector motors (918) operatively connected to the winch drum. The motors are controlled by a motor controller (34) which senses operational load on the winch drum and adjusts operating parameters of the motors to maintain belt tension within a desired range.
Description
wo 98/03414 PCT~US97/13868 3Endless conveyors and mobile or advancing conveyors 4 used ln mining and various other applications employ a tensioning device to maintain the conveyor belt at a 6 constant or predetermined tension. In the past, such 7 tension has typically been provided by a hydraulic winch.
8 The hydraulic winches are used on a conveyor take-up or g storage unit and apply a constant pull on the conveyor carriage which, in turn, regulates tension applied to the 11 conveyor belt to insure traction at the main drive. When a 12 slack belt is absorbed by the take-up, the winch winds or 13 pays in, if tension becomes too great, the winch unwinds or 14 pays out. Devices of this type are well known in the art, as illustrated by U.S. Patent Nos. 3,537,573; 3,675,482;
16 3,923,151; 4,037,876; 4,090,601; 4,50~,213; 4,653,634;
17 4,803,804; and, 5,131,528, the disclosures of which are 18 expressly incorporated herein in their entireties.
i9 Unfortunately, hydraulic units re~uire excessive maintenance, such as changing filters, oil and replacing 21 pressure worn components. Hydraulic units also require a 22 large number of moving parts, and run in an open loop 23 constant pressure mode.
24 Therefore, there exists a need in the art for an improved tensioning winch which removes at least some of 26 the aforementioned disadvantages of the tensioning devices 27 known in the art.
28 SUMMARY OF TH~ INVENTION
29 The present invention is directed toward a conveyor tensioning system which eliminates at least some of the 31 deficiencies present in hydraulic belt tensioning systems.
32 The present invention is also directed toward an assembly 33 which can utilize either hydraulic or electric brakes.
WO 98/03414 PCT~US97/13868 1 In accordance with one embo-diment of the present 2 invention, the tensioning assembly includes a winch drum 3 having a torque hub or planetary gearbox mounted within 4 each end thereof, hydraulic brakes mounted to each gearbox, and a pair of drum input shafts extending from the brakes 6 and operatively interconnected with the drum. Each of the 7 input shafts includes a sprocket which is drivably 8 connected to a chain-type drive belt.
9 In further accordance with the present invention, a pair of motors are located relatively behind the winch drum ll and include output shafts Each of the output shafts 12 includes a sprocket which is rotata~ly connected to an 13 associated input shaft of the winch drum via the drive 14 belt.
In further accordance with the present invention, the 16 motors are ac vector motors in which torque changes rapidly 17 to accommodate changing load conditions during conveyor 18 operation. The motors do not have a transient tor~ue 19 response, but rather have a torque response which tracks the load-required torque to more accurately control 21 operation of the winch in response to variable load 2~- conditions.
23 BRIEF DESCRIPTION OF THE DR~WING FIGURES
24 These and further features of the present invention will be apparent with reference to the following 26 description and drawings, wherein:
27 FIG. 1 is a graph of a typical curve of torque versus 28 speed for a variable frequency electric motor;
29 FIG. 2 is a graph of the torque response of a variable ~requency electric motor;
31 FIG. 3 is a graph of the torque versus speed of a 32 motor having flux vector control;
33 ~IG. 4 is a graph of the tor~ue response of a motor 34 having flux vector control;
~IG. 5 is a schematic illustration of a drive W O 98/~3414 PCTrUS97~13868 1 7ch~ism using the torque vector-winch according to a 2 first embodiment o~ the present invention;
3 FIG. 6 is a top plàn view of a vector tensionin~ winch 4 according to the first embodiment of the present invention;
FIG. 7 is a side elevational view of the vector 6 tensioning winch shown in FIG. 6;
7 FIG. 8 is a schematic illustration of a drive m~ch~n;sm using the torque vector winch according to a 9 second embodiment of the present invention;
FIG. 9 is a top plan view of a vector tensioning winch 11 according to the second embodiment of the present 12 invention;
13 FIG. 10 is a side elevational view of the vector 14 tensioning winch shown in FIG. 9.
D~TAILED DESCRIPTION OF T~E PR~F~RRED EMBODIMENT
16 It should be noted that in the detailed description 17 which follows, identical components have the same reference 18 numeral, regard~ess of wh~ther they are shown in different 19 embodiments of the present invention. It should also be noted that, in order to clearly and concisely disclose the 21 present invention, the drawings may not necessarily be to 22 scale and certain features of the invention may be shown in 23 somewhat schematic form.
24 With reference to FIGS. 6 and 7, an AC torque vector winch a,ssembly lO according to a first embodiment of the 26 present invention is illustrated. The assembly 10 27 comprises a winch base 12, winch drum 14, a pair of 28 supporting end brackets 16, and a pair of ac torgue vector 29 motors 18. Each end of the drum 14 has a planetary gearbox 20 therein. Each planetary gearbox 20 has a failsafe brake 31 22 inserted therein. The failsafe brakes 22 are secured to 32 an associated end bracket 16 which, in turn, supports the 33 end o~ the winch drum 14, as illustrated. An input or 34 adaptor shaft 24 extends from each brake 22, and has a first sprocket 26 secured to a free end thereof.
W O 98/03414 PCTAUS97/1386~
1 The vector motors 18 are located relatively behind the 2 winch drum 24. Each of the vector motors 18 has an output 3 shaft 28 that is generally parallel to the adaptor or input 4 shaft 24 extending from the winch drum 14. The output shafts 28 of the vector motors 18 are spaced a distance 6 above the winch base 12 which is generally identical to the 7 distance that the adaptor or input shafts 24 are spaced 8 above the winch base 12, as illustrated.
9 Each output shaft 28 has a second sprocket 30 secured thereto. Each of the second sprockets 30 is generally in-11 line with an associated first sprocket 26, and is connected 12 to the first sprocket 26 by a polychain-type drive belt 32.
13 Each of the motors 18 includes a motor controller 34 tha~
14 controls operation of the motor 18 to maintain proper tension on the conveyor belt (not shown) by means of the 16 winch drum 14. As is well known in the art, rotation of 17 the winch drum 14 pays in or pays out a cable (no~ shown) 18 which is connected to a conveyor carriage (not shown) and 19 thereby adjusts the tension on the conveyor belt carried by the carriage.
21 With reference to FIGS. 8-lo, an assembly 10' ~2 according to a second embodiment of the present invention 23 is illustrated. As noted hereinbefore, structural 24 components common to the first and second embodiments have been given the same reference numeral in the drawings and 26 description for purposes of clarity.
27 The assembly 10' comprises a winch base 12, winch drum 28 14, a pair of supporting end brackets 16, and a pair of ac 29 torque vector motors 18. Each end of the drum 14 has a planetary gearbox 20 therein. Each planetary gearbox 20 31 has an input or adaptor shaft 24 inserted therein. The 32 input or adaptor shaft 24 extends from each gearbox 22, 33 through a first sprocket 26, and has a free end thereof 34 secured to an electric brake 22a. As such, the electric brakes 22a are laterally outboard of the first sprockets 36 26, and directly engage and the input shaft 24 which, in 37 turn, is directly engaged with the gearbox 20 that is W O 981034~4 PCTrUS97/~3868 1 rigidly attached to the winch drum 14 for mutual or common 2 rotation therewith.
3 A5 in the first embodiment, the vector motors 18 are 4 located relatively behind the winch drum 24. Ea~h of the vector motors 18 has an output shaft 28 that is generally 6 parallel to the adaptor or input shaft 24 extending from 7 the winch drum 14. The output shafts 28 of the vector 8 motors 18 are spaced a distance above the winch ba~e 12 9 which is generally identical to the distance that the adaptor or input sha~ts 24 are spaced above the winch base 11 12, as illustrated.
12 Each output shaft 28 has a second sprocket 30 secured 13 thereto. Each of the second sprockets 30 is generally in-14 line with an associated first sprocket 26, and is connected to the first sprocket 26 by a polychain-type drive belt 32.
16 Each of the motors 18 includes a motor controller 34 that 17 controls operation of the motor 18 to maintain proper 18 tension on the conveyor belt (not shown~ by means of the 19 winch drum 14. As is well known in the art, rotation of the winch drum 14 pays in or pays out a cable (not shown) 21 which is connected to a conveyor carriage (not shown) and ~ thereby adjusts the tension on the conveyor belt carried by 23 the carriage. Whereas prior art hydraulic winches operate 24 in an open-loop, constant pressure mode, the electric vector motor winch according to the present invention 26 operates in a closed loop, tension feedback mode. Sensors, 27 such as Kistler Morse load cells, correlate winch line pull 28 to actual operating conveyor belt tension, and this is used 29 by the motor controller to operate the vector motors and thereby rotate the winch drum 14 to maintain the pull line, 31 and hence the conveyor belt tension, within desired 32 operating parameters.
33 One type of vector motor successfully used, is 34 manufactured by BALDOR, Model No. ZDM4316T, (further identified as 75 HP, 17~0 RPM, 460 VAC, three phase, 60 Hz 36 365 T-frame). It is submitted that various other vector 37 motors are known in the art and may be used with e~ual W O 98/03414 PCT~US97/13868 1 functionality.
2 With reference to FIGS. 1 and 2, graphs of the 3 operational response of a variable frequency control motor 4 are illustrated. With reference to FIG. 1, it is shown that the torque of the motor is variable, and depends upon 6 the speed at which the motor is operated. A variable 7 frequency controlled motor also has a dead zone which from 8 zero rpm to some minimum frequency. Typically, frequency 9 control has a transient region, shown in ~oth FIGS. 1 and 2, wherein the motor produced torque does not follow the 11 load required torque. As such, variable frequency 12 controlled motors have not been suitable for conveyor 13 tensioning applications wherein the required and motor-14 provided torque must correspond to one another.
Contrarily, as shown in FIGS. 3 and 4, a vector motor 16 18 as used in the present invention provides constant 17 torque at a range of rotational speeds, including zero rpm.
18 As such, the torque provided by the vector motors used in 19 the present invention can track or follow the required torque, which corresponds to the conveyor load, as the 21 conveyor load/tension varies, and provides steady-state 2~ control of the tension on the winch.
23 The vector motor controller 34 preferably has sixteen 24 bit resolution that can process approximately 3000 calculations per second, and constantly samples and updates 26 control parameters, such as torque, frequency, phase angle, 27 etc. Generally speaking, the primary current I1 is divided 28 into two components, the magnetizing current IM' which is 29 magnetizing flux, and the torque-producing current IT~ which is converted into rotor torque (I1=IM + IT). With vector 31 control, torque response i5 rapid, and there is no 32 transient and, therefore, vector motors do not suffer from 33 the disadvantages inherent in variable frequency controlled 34 motors mentioned hereinbefore.
The primary current, the torque current, the 36 magnetizing current, and the angle between the torque and 37 magnetizing currents ~ constantly monitored and controlled 9~
~ -6-W O 98JO3414 P~l/U~9~/13X68 l by the motor controller 34 in response to C~nQ~
2 load/tor~ue to provide the nec~sls~ry output torque, and 3 thereby provides rapid or almost i -~iate variation in the 4 operating parameters of the motors which follow the tension requirements of the conveyor belt during use, and maintain 6 the belt tension within a predetermined desired operatin~
7 range.
8 AC induction motors generally conform to the following g e~uations:
1 0 S_ ( NS--NR ) /NS
11 N5=( (120--f) / (P/NS) ) (~--S~ ~ T
12 S ~ T
13 It=IH + IT
14 wherein Ns is stator speed, NR is rotor speed, S is slip, P
is load, f is fre~uency, and T is torque.
16 In vector motors, when the load increases, the primary 17 current increases,~he magnetizin~ current increases, 1~ torque current increases, and the slip frequency (Ws) 19 increases. Therefore, when more torque is required, the motor controller provides increased torque current to 21 thereby incre~se the torque output at the rotor or motor 22 output shaft. Conversely, when less torque is required, 23 the motor controller provides decreased torque current to 24 thereby decrease the torque output at the motor output shaft 28.
26 In the assembly according to the present invention, 27 the laad on the motor is directly related to the load on 28 the winch which, in turn, is equivalent to the tension on 29 the conveyor belt. As the tension on the conveyor belt 30 varies during use, the load on the motor, and the tor~ue .
31 current and the motor produced torque varies accordingly, ~,~
32 as shown in FIG. 4.
33 The preferred embodiment of the present invention has 34 been described in the foregoing, but is not limited thereto. Rather, the present invention is only defined by 36 the claims appended hereto.
_
8 The hydraulic winches are used on a conveyor take-up or g storage unit and apply a constant pull on the conveyor carriage which, in turn, regulates tension applied to the 11 conveyor belt to insure traction at the main drive. When a 12 slack belt is absorbed by the take-up, the winch winds or 13 pays in, if tension becomes too great, the winch unwinds or 14 pays out. Devices of this type are well known in the art, as illustrated by U.S. Patent Nos. 3,537,573; 3,675,482;
16 3,923,151; 4,037,876; 4,090,601; 4,50~,213; 4,653,634;
17 4,803,804; and, 5,131,528, the disclosures of which are 18 expressly incorporated herein in their entireties.
i9 Unfortunately, hydraulic units re~uire excessive maintenance, such as changing filters, oil and replacing 21 pressure worn components. Hydraulic units also require a 22 large number of moving parts, and run in an open loop 23 constant pressure mode.
24 Therefore, there exists a need in the art for an improved tensioning winch which removes at least some of 26 the aforementioned disadvantages of the tensioning devices 27 known in the art.
28 SUMMARY OF TH~ INVENTION
29 The present invention is directed toward a conveyor tensioning system which eliminates at least some of the 31 deficiencies present in hydraulic belt tensioning systems.
32 The present invention is also directed toward an assembly 33 which can utilize either hydraulic or electric brakes.
WO 98/03414 PCT~US97/13868 1 In accordance with one embo-diment of the present 2 invention, the tensioning assembly includes a winch drum 3 having a torque hub or planetary gearbox mounted within 4 each end thereof, hydraulic brakes mounted to each gearbox, and a pair of drum input shafts extending from the brakes 6 and operatively interconnected with the drum. Each of the 7 input shafts includes a sprocket which is drivably 8 connected to a chain-type drive belt.
9 In further accordance with the present invention, a pair of motors are located relatively behind the winch drum ll and include output shafts Each of the output shafts 12 includes a sprocket which is rotata~ly connected to an 13 associated input shaft of the winch drum via the drive 14 belt.
In further accordance with the present invention, the 16 motors are ac vector motors in which torque changes rapidly 17 to accommodate changing load conditions during conveyor 18 operation. The motors do not have a transient tor~ue 19 response, but rather have a torque response which tracks the load-required torque to more accurately control 21 operation of the winch in response to variable load 2~- conditions.
23 BRIEF DESCRIPTION OF THE DR~WING FIGURES
24 These and further features of the present invention will be apparent with reference to the following 26 description and drawings, wherein:
27 FIG. 1 is a graph of a typical curve of torque versus 28 speed for a variable frequency electric motor;
29 FIG. 2 is a graph of the torque response of a variable ~requency electric motor;
31 FIG. 3 is a graph of the torque versus speed of a 32 motor having flux vector control;
33 ~IG. 4 is a graph of the tor~ue response of a motor 34 having flux vector control;
~IG. 5 is a schematic illustration of a drive W O 98/~3414 PCTrUS97~13868 1 7ch~ism using the torque vector-winch according to a 2 first embodiment o~ the present invention;
3 FIG. 6 is a top plàn view of a vector tensionin~ winch 4 according to the first embodiment of the present invention;
FIG. 7 is a side elevational view of the vector 6 tensioning winch shown in FIG. 6;
7 FIG. 8 is a schematic illustration of a drive m~ch~n;sm using the torque vector winch according to a 9 second embodiment of the present invention;
FIG. 9 is a top plan view of a vector tensioning winch 11 according to the second embodiment of the present 12 invention;
13 FIG. 10 is a side elevational view of the vector 14 tensioning winch shown in FIG. 9.
D~TAILED DESCRIPTION OF T~E PR~F~RRED EMBODIMENT
16 It should be noted that in the detailed description 17 which follows, identical components have the same reference 18 numeral, regard~ess of wh~ther they are shown in different 19 embodiments of the present invention. It should also be noted that, in order to clearly and concisely disclose the 21 present invention, the drawings may not necessarily be to 22 scale and certain features of the invention may be shown in 23 somewhat schematic form.
24 With reference to FIGS. 6 and 7, an AC torque vector winch a,ssembly lO according to a first embodiment of the 26 present invention is illustrated. The assembly 10 27 comprises a winch base 12, winch drum 14, a pair of 28 supporting end brackets 16, and a pair of ac torgue vector 29 motors 18. Each end of the drum 14 has a planetary gearbox 20 therein. Each planetary gearbox 20 has a failsafe brake 31 22 inserted therein. The failsafe brakes 22 are secured to 32 an associated end bracket 16 which, in turn, supports the 33 end o~ the winch drum 14, as illustrated. An input or 34 adaptor shaft 24 extends from each brake 22, and has a first sprocket 26 secured to a free end thereof.
W O 98/03414 PCTAUS97/1386~
1 The vector motors 18 are located relatively behind the 2 winch drum 24. Each of the vector motors 18 has an output 3 shaft 28 that is generally parallel to the adaptor or input 4 shaft 24 extending from the winch drum 14. The output shafts 28 of the vector motors 18 are spaced a distance 6 above the winch base 12 which is generally identical to the 7 distance that the adaptor or input shafts 24 are spaced 8 above the winch base 12, as illustrated.
9 Each output shaft 28 has a second sprocket 30 secured thereto. Each of the second sprockets 30 is generally in-11 line with an associated first sprocket 26, and is connected 12 to the first sprocket 26 by a polychain-type drive belt 32.
13 Each of the motors 18 includes a motor controller 34 tha~
14 controls operation of the motor 18 to maintain proper tension on the conveyor belt (not shown) by means of the 16 winch drum 14. As is well known in the art, rotation of 17 the winch drum 14 pays in or pays out a cable (no~ shown) 18 which is connected to a conveyor carriage (not shown) and 19 thereby adjusts the tension on the conveyor belt carried by the carriage.
21 With reference to FIGS. 8-lo, an assembly 10' ~2 according to a second embodiment of the present invention 23 is illustrated. As noted hereinbefore, structural 24 components common to the first and second embodiments have been given the same reference numeral in the drawings and 26 description for purposes of clarity.
27 The assembly 10' comprises a winch base 12, winch drum 28 14, a pair of supporting end brackets 16, and a pair of ac 29 torque vector motors 18. Each end of the drum 14 has a planetary gearbox 20 therein. Each planetary gearbox 20 31 has an input or adaptor shaft 24 inserted therein. The 32 input or adaptor shaft 24 extends from each gearbox 22, 33 through a first sprocket 26, and has a free end thereof 34 secured to an electric brake 22a. As such, the electric brakes 22a are laterally outboard of the first sprockets 36 26, and directly engage and the input shaft 24 which, in 37 turn, is directly engaged with the gearbox 20 that is W O 981034~4 PCTrUS97/~3868 1 rigidly attached to the winch drum 14 for mutual or common 2 rotation therewith.
3 A5 in the first embodiment, the vector motors 18 are 4 located relatively behind the winch drum 24. Ea~h of the vector motors 18 has an output shaft 28 that is generally 6 parallel to the adaptor or input shaft 24 extending from 7 the winch drum 14. The output shafts 28 of the vector 8 motors 18 are spaced a distance above the winch ba~e 12 9 which is generally identical to the distance that the adaptor or input sha~ts 24 are spaced above the winch base 11 12, as illustrated.
12 Each output shaft 28 has a second sprocket 30 secured 13 thereto. Each of the second sprockets 30 is generally in-14 line with an associated first sprocket 26, and is connected to the first sprocket 26 by a polychain-type drive belt 32.
16 Each of the motors 18 includes a motor controller 34 that 17 controls operation of the motor 18 to maintain proper 18 tension on the conveyor belt (not shown~ by means of the 19 winch drum 14. As is well known in the art, rotation of the winch drum 14 pays in or pays out a cable (not shown) 21 which is connected to a conveyor carriage (not shown) and ~ thereby adjusts the tension on the conveyor belt carried by 23 the carriage. Whereas prior art hydraulic winches operate 24 in an open-loop, constant pressure mode, the electric vector motor winch according to the present invention 26 operates in a closed loop, tension feedback mode. Sensors, 27 such as Kistler Morse load cells, correlate winch line pull 28 to actual operating conveyor belt tension, and this is used 29 by the motor controller to operate the vector motors and thereby rotate the winch drum 14 to maintain the pull line, 31 and hence the conveyor belt tension, within desired 32 operating parameters.
33 One type of vector motor successfully used, is 34 manufactured by BALDOR, Model No. ZDM4316T, (further identified as 75 HP, 17~0 RPM, 460 VAC, three phase, 60 Hz 36 365 T-frame). It is submitted that various other vector 37 motors are known in the art and may be used with e~ual W O 98/03414 PCT~US97/13868 1 functionality.
2 With reference to FIGS. 1 and 2, graphs of the 3 operational response of a variable frequency control motor 4 are illustrated. With reference to FIG. 1, it is shown that the torque of the motor is variable, and depends upon 6 the speed at which the motor is operated. A variable 7 frequency controlled motor also has a dead zone which from 8 zero rpm to some minimum frequency. Typically, frequency 9 control has a transient region, shown in ~oth FIGS. 1 and 2, wherein the motor produced torque does not follow the 11 load required torque. As such, variable frequency 12 controlled motors have not been suitable for conveyor 13 tensioning applications wherein the required and motor-14 provided torque must correspond to one another.
Contrarily, as shown in FIGS. 3 and 4, a vector motor 16 18 as used in the present invention provides constant 17 torque at a range of rotational speeds, including zero rpm.
18 As such, the torque provided by the vector motors used in 19 the present invention can track or follow the required torque, which corresponds to the conveyor load, as the 21 conveyor load/tension varies, and provides steady-state 2~ control of the tension on the winch.
23 The vector motor controller 34 preferably has sixteen 24 bit resolution that can process approximately 3000 calculations per second, and constantly samples and updates 26 control parameters, such as torque, frequency, phase angle, 27 etc. Generally speaking, the primary current I1 is divided 28 into two components, the magnetizing current IM' which is 29 magnetizing flux, and the torque-producing current IT~ which is converted into rotor torque (I1=IM + IT). With vector 31 control, torque response i5 rapid, and there is no 32 transient and, therefore, vector motors do not suffer from 33 the disadvantages inherent in variable frequency controlled 34 motors mentioned hereinbefore.
The primary current, the torque current, the 36 magnetizing current, and the angle between the torque and 37 magnetizing currents ~ constantly monitored and controlled 9~
~ -6-W O 98JO3414 P~l/U~9~/13X68 l by the motor controller 34 in response to C~nQ~
2 load/tor~ue to provide the nec~sls~ry output torque, and 3 thereby provides rapid or almost i -~iate variation in the 4 operating parameters of the motors which follow the tension requirements of the conveyor belt during use, and maintain 6 the belt tension within a predetermined desired operatin~
7 range.
8 AC induction motors generally conform to the following g e~uations:
1 0 S_ ( NS--NR ) /NS
11 N5=( (120--f) / (P/NS) ) (~--S~ ~ T
12 S ~ T
13 It=IH + IT
14 wherein Ns is stator speed, NR is rotor speed, S is slip, P
is load, f is fre~uency, and T is torque.
16 In vector motors, when the load increases, the primary 17 current increases,~he magnetizin~ current increases, 1~ torque current increases, and the slip frequency (Ws) 19 increases. Therefore, when more torque is required, the motor controller provides increased torque current to 21 thereby incre~se the torque output at the rotor or motor 22 output shaft. Conversely, when less torque is required, 23 the motor controller provides decreased torque current to 24 thereby decrease the torque output at the motor output shaft 28.
26 In the assembly according to the present invention, 27 the laad on the motor is directly related to the load on 28 the winch which, in turn, is equivalent to the tension on 29 the conveyor belt. As the tension on the conveyor belt 30 varies during use, the load on the motor, and the tor~ue .
31 current and the motor produced torque varies accordingly, ~,~
32 as shown in FIG. 4.
33 The preferred embodiment of the present invention has 34 been described in the foregoing, but is not limited thereto. Rather, the present invention is only defined by 36 the claims appended hereto.
_
Claims (20)
1. A conveyor belt tensioning assembly, comprising:
a winch drum, said drum comprising a cylindrical body having first and second ends;
first and second planetary gearboxes, said first gearbox being disposed within said first end and said second gearbox being disposed within said second end;
first and second brakes, said first brake being secured to said first gearbox and said second brake being secured to said second gearbox;
first and second input shafts, said first input shaft being secured to, and extending outwardly from, said first brake and said second input shaft being secured to, and extending outwardly from, said second brake, first and second input sprockets, said first input sprocket being secured to a free end of said first input shaft and said second input sprocket being secured to a free end of said second input shaft;
first and second electric motors, said first electric motor including a first output shaft and said second electric motor including a second output shaft, said first output shaft having a first output sprocket secured to a free end thereof and said second output shaft having a second output shaft secured to a free end thereof;
a first drive belt operatively linking said first output shaft to said first input shaft and a second drive belt operatively linking said second output shaft to said second input shaft.
a winch drum, said drum comprising a cylindrical body having first and second ends;
first and second planetary gearboxes, said first gearbox being disposed within said first end and said second gearbox being disposed within said second end;
first and second brakes, said first brake being secured to said first gearbox and said second brake being secured to said second gearbox;
first and second input shafts, said first input shaft being secured to, and extending outwardly from, said first brake and said second input shaft being secured to, and extending outwardly from, said second brake, first and second input sprockets, said first input sprocket being secured to a free end of said first input shaft and said second input sprocket being secured to a free end of said second input shaft;
first and second electric motors, said first electric motor including a first output shaft and said second electric motor including a second output shaft, said first output shaft having a first output sprocket secured to a free end thereof and said second output shaft having a second output shaft secured to a free end thereof;
a first drive belt operatively linking said first output shaft to said first input shaft and a second drive belt operatively linking said second output shaft to said second input shaft.
2. A conveyor belt tensioning assembly according to claim 1, wherein said electric motors are ac flux vector motors.
3. A conveyor belt tensioning assembly according to claim 2, wherein each of said ac flux vector motors includes a motor controller, said motor controller monitoring tension on said drive belt and controlling operation of said motor to maintain the drive belt tension within a predetermined range.
4. A conveyor belt tensioning assembly according to claim 3, further comprising a winch base and a pair of winch supporting end brackets, said end brackets being secured to said winch base and extend upwardly therefrom and being operable to support said winch drum above said winch base.
5. A conveyor belt tensioning assembly according to claim 4, wherein each of said input shafts and said output shafts are spaced a predetermined and identical distance above said winch base.
6. A conveyor belt tensioning assembly according to claim 5, wherein each of said motors is mounted upon a platform, said platform being secured to said winch base.
7. A conveyor belt tensioning assembly according to claim 2, wherein said second sprockets are relatively smaller in diameter than said first sprockets.
8. A conveyor belt tensioning assembly, comprising:
a winch drum, said drum comprising a cylindrical body having first and second ends;
a support base disposed relatively beneath said winch drum;
a pair of supporting brackets, each of said supporting brackets being secured to said support base and being operable to support said drum relatively above said base;
first and second planetary gearboxes, said first gearbox being disposed within said drum first end and said second gearbox being disposed within said drum second end;
first and second brakes, said first brake being secured to said first gearbox and said second brake being secured to said second gearbox;
first and second input shafts, said first input shaft being secured to, and extending outwardly from, said first brake and said second input shaft being secured to, and extending outwardly from, said second brake;
first and second input sprockets, said first input sprocket being secured to a free end of said first input shaft and said second input sprocket being secured to a free end of said second input shaft;
first and second ac flux vector motors, said first motor including a first output shaft and said second motor including a second output shaft, said first output shaft having a first output sprocket secured to a free end thereof and said second output shaft having a second output shaft secured to a free end thereof;
a first drive belt operatively linking said first output sprocket to said first input sprocket; and, a second drive belt operatively linking said second output sprocket to said second input sprocket.
a winch drum, said drum comprising a cylindrical body having first and second ends;
a support base disposed relatively beneath said winch drum;
a pair of supporting brackets, each of said supporting brackets being secured to said support base and being operable to support said drum relatively above said base;
first and second planetary gearboxes, said first gearbox being disposed within said drum first end and said second gearbox being disposed within said drum second end;
first and second brakes, said first brake being secured to said first gearbox and said second brake being secured to said second gearbox;
first and second input shafts, said first input shaft being secured to, and extending outwardly from, said first brake and said second input shaft being secured to, and extending outwardly from, said second brake;
first and second input sprockets, said first input sprocket being secured to a free end of said first input shaft and said second input sprocket being secured to a free end of said second input shaft;
first and second ac flux vector motors, said first motor including a first output shaft and said second motor including a second output shaft, said first output shaft having a first output sprocket secured to a free end thereof and said second output shaft having a second output shaft secured to a free end thereof;
a first drive belt operatively linking said first output sprocket to said first input sprocket; and, a second drive belt operatively linking said second output sprocket to said second input sprocket.
9. A conveyor belt tensioning assembly according to claim 8, wherein each of said first and second motors includes a motor controller, said motor controller monitoring tension on an associated drive belt and controlling operation of said motor to maintain the drive belt tension within a predetermined range.
10. A conveyor belt tensioning assembly according to claim 9, wherein each of said input shafts and said output shafts are spaced a predetermined and identical distance above said winch base.
11. A conveyor belt tensioning assembly according to claim 10, wherein each of said motors is mounted upon a platform, said platform being secured to said winch base.
12. A conveyor belt tensioning assembly according to claim 11, wherein said second sprockets are relatively smaller in diameter than said first sprockets.
13. A conveyor belt tensioning assembly, comprising:
a winch drum, said drum comprising a cylindrical body having first and second ends;
first and second planetary gearboxes, said first gearbox being disposed within said first end and said second gearbox being disposed within said second end;
first and second brakes, said first brake being secured to said first gearbox and said second brake being secured to said second gearbox;
first and second input shafts, said first input shaft being secured to, and extending outwardly from said first gearbox and said second input shaft being secured to, and extending outwardly from, said second gearbox;
first and second brakes, said first brake being secured to said first input shaft and said second brake being secured to said second input shaft;
first and second input sprockets, said first input sprocket being secured to said first input shaft intermediate said first brake and said first gearbox and said second input sprocket being secured said second input shaft intermediate said second brake and said second gearbox;
first and second electric motors, said first electric motor including a first output shaft and said second electric motor including a second output shaft, said first output shaft having a first output sprocket secured to a free end thereof and said second output shaft having a second output shaft secured to a free end thereof;
a first drive belt operatively linking said first output shaft to said first input shaft and a second drive belt operatively linking said second output shaft to said second input shaft.
a winch drum, said drum comprising a cylindrical body having first and second ends;
first and second planetary gearboxes, said first gearbox being disposed within said first end and said second gearbox being disposed within said second end;
first and second brakes, said first brake being secured to said first gearbox and said second brake being secured to said second gearbox;
first and second input shafts, said first input shaft being secured to, and extending outwardly from said first gearbox and said second input shaft being secured to, and extending outwardly from, said second gearbox;
first and second brakes, said first brake being secured to said first input shaft and said second brake being secured to said second input shaft;
first and second input sprockets, said first input sprocket being secured to said first input shaft intermediate said first brake and said first gearbox and said second input sprocket being secured said second input shaft intermediate said second brake and said second gearbox;
first and second electric motors, said first electric motor including a first output shaft and said second electric motor including a second output shaft, said first output shaft having a first output sprocket secured to a free end thereof and said second output shaft having a second output shaft secured to a free end thereof;
a first drive belt operatively linking said first output shaft to said first input shaft and a second drive belt operatively linking said second output shaft to said second input shaft.
14. A conveyor belt tensioning assembly according to claim 13, wherein said electric motors are ac flux vector motors.
15. A conveyor belt tensioning assembly according to claim 14, wherein each of said ac flux vector motors includes a motor controller, said motor controller monitoring tension on said drive belt and controlling operation of said motor to maintain the drive belt tension within a predetermined range.
16. A conveyor belt tensioning assembly according to claim 15, further comprising a winch base and a pair of winch supporting end brackets, said end brackets being secured to said winch base and extend upwardly therefrom and being operable to support said winch drum above said winch base.
17. A conveyor belt tensioning assembly according to claim 16, wherein each of said input shafts and said output shafts are spaced a predetermined and identical distance above said winch base.
18. A conveyor belt tensioning assembly according to claim 17, wherein each of said motors is mounted upon a platform, said platform being secured to said winch base.
19. A conveyor belt tensioning assembly according to claim 14, wherein said second sprockets are relatively smaller in diameter than said first sprockets.
20. A conveyor belt tensioning assembly according to claim 13, wherein said brakes are electric brakes.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US2202596P | 1996-07-22 | 1996-07-22 | |
| US60/022,025 | 1996-07-22 | ||
| US08/767,630 | 1996-12-17 | ||
| US08/767,630 US5788058A (en) | 1996-12-17 | 1996-12-17 | ac torque vector winch |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2229443A1 true CA2229443A1 (en) | 1998-01-29 |
Family
ID=26695389
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2229443 Abandoned CA2229443A1 (en) | 1996-07-22 | 1997-07-21 | Ac torque vector winch |
Country Status (4)
| Country | Link |
|---|---|
| AU (1) | AU704548B2 (en) |
| CA (1) | CA2229443A1 (en) |
| NZ (1) | NZ329989A (en) |
| WO (1) | WO1998003414A1 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19911641C1 (en) * | 1999-03-16 | 2000-07-20 | Lausitzer Braunkohle Ag | Conveyor belt tension control has a tensioning drum to deflect the path of the lower level with a setting unit and a process computer to modify the nominal tension value according to the current working conditions |
| DE102004051479A1 (en) * | 2004-10-22 | 2006-04-27 | Fedder, Dieter, Dipl.-Ing. | Operating method for spiral conveyor system, involves gathering data relating to position of balance roll in conveyor system, and using this data to control servo unit which in turn powers drum drive of system |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3251455A (en) * | 1963-08-05 | 1966-05-17 | Litton Industries Inc | Belt conveyor storage section with longitudinally unsymmetrical transfer pulleys |
| US4440293A (en) * | 1980-12-18 | 1984-04-03 | Allis-Chalmers Corporation | Sling belt bulk material conveyor |
-
1997
- 1997-07-21 AU AU39725/97A patent/AU704548B2/en not_active Ceased
- 1997-07-21 NZ NZ329989A patent/NZ329989A/en unknown
- 1997-07-21 CA CA 2229443 patent/CA2229443A1/en not_active Abandoned
- 1997-07-21 WO PCT/US1997/013868 patent/WO1998003414A1/en active Application Filing
Also Published As
| Publication number | Publication date |
|---|---|
| AU3972597A (en) | 1998-02-10 |
| NZ329989A (en) | 2000-01-28 |
| WO1998003414A1 (en) | 1998-01-29 |
| AU704548B2 (en) | 1999-04-29 |
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| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Dead |