DE102008036288B4 - Lift-lowering conveyor with vertically arranged lifters - Google Patents

Abstract

The invention relates to a lifting-lowering conveyor with detection of the roller movement by a rotary encoder, for example, according to the induction principle or other principles, which measures the position of the rollers accurately and an intermediate controller that evaluates this information and with additional information of two initiators at the Upper and lower stop position of the lift on the engine on command from the higher-level control on and off again in the position reached.

Description

The invention relates to a lifting-lowering conveyor with vertically arranged lifting, each having a groove roller, which are driven synchronously by a common drive motor via contactors or frequency converter, such that a lift on which a carrier (Skid) with driven Roller conveyor is arranged, can be driven without jerking up and down, the lift engages rolling pins in a respective groove of the respective groove roller, wherein the grooves depict the sequence of movements for the lift, such that the lift in their respective end positions - above and below - gently, the lift is locked by a Rastgang the grooves in the respective end position.

State of the art

Lift-lowering conveyor of the presumed genus are also referred to as "lifter towers" with which motorized roller conveyors can be lifted vertically from a lower position over a middle position (load transfer position) to an upper position and successively lowered again. Often they are arranged in a row one behind the other and thus allow in the upper position the transport of so-called skids, which serve as a carrier for body parts or the like from station to station. Several such lift-lowering conveyor can be arranged behind one another in a conveyor track and promote the body parts or the like to be transported to the respective processing stations such as welding robots or assembly robots. In the respective station then the roller conveyors are lowered again, the component is deposited on fixed pick-up points (load transfer) and roller conveyors with skids are driven even further down to allow the respective assembly or welding robots or the like access to the component.

A roller conveyor is usually held by two jacks with lateral slide in vertical longitudinal guides. The lift or carriages each protrude with a roller bolt into a groove roller whose rotation and groove shape moves the carriage up and down. The slope of the groove in the roller forms the motion from, in particular the jerk-free transfer of the load by braking to a standstill at the takeover point and renewed acceleration and the locking of the lift or the like in the upper position by a so-called Rastgang (horizontal Nutverlauf), the one Movement of the roller prevented by the gravity of the roller conveyor. The web is virtually locked in the upper position. The groove rollers are usually synchronously rotated by a central motor with rigidly connected cardan shafts and deflections. For a complete movement of the lifters, the groove rollers typically rotate two to five times, depending on the lifting height. The wiring of the central engine via cams on a switching disc, which is driven by a suitable reduction of the grooved roller, wherein a disc rotation corresponds to the total number of revolutions of the roller. Cams at the beginning and end of the movement switch the motor, also an overflow protection is ensured by further cams. The higher-level system control (PLC) is additionally signaled separately by top and bottom initiators, in which position the lifter and thus the roller conveyor is located.

This previously known solution is relatively space consuming, susceptible to wear and sensitive. The higher-level system PLC takes over the interrogation of the switches and controls the motor via contactors or frequency converters. This results in a considerable programming effort with cam adjustment. Commissioning is relatively expensive.

From the DE 101 62 178 A1 a lifting device for moving loads with a rotatable lifting spindle is already known, in whose cylindrical surface area at least one helical recess is formed, with at least one pin which engages in the at least one helical recess and is connected for lifting a load, each with a working carriage, the is guided in a guide device which allows only a movement of the respective working carriage, wherein the movement is substantially parallel to the axis of rotation of the lifting spindle, and with a drive for the lifting spindle, wherein the at least one helical recess in its course has different slopes. For this purpose, a pin roller engages horizontally in a groove track, which is arranged helically in a lateral surface of the lifting spindle. The slope of the groove can also take the value of zero in places. Thus, the load can remain at the relevant point despite a rotational movement of the lifting spindle at a certain vertical position. The whole thing is driven by a three-phase motor with a reduction gear, which drives a first lifting spindle. This reduction gear reduces the number of revolutions of the three-phase motor to a maximum of one revolution of the first lifting spindle. A signal generator is used to determine the number of revolutions of the three-phase motor.

The JP 2002 068 681 A relates to a bolt which is driven by a motor. A signal is detected which is detected by a photoelectric switch and which is attached to the screw shaft. The counted number of revolutions are used to turn the motor on and off.

From the DE 94 12 971 U1 is a lifting table with a liftable in the vertical direction and lowered lifting platform previously known, which is provided to achieve a given stroke characteristic with a switched on the lifting drive stepper, the at least one motor rotatably driven, stationarily arranged cylindrical roller with incorporated in its scope cam groove as a driving Having member and a control groove engaging in the control pin, which is arranged on a coupled to the lifting platform longitudinally displaceably mounted output member, wherein the cylinder roller is rotatably driven about a vertical axis on the ground or a mounted on the substrate frame structure is or are, and that the output member or the drive components of his or her part parallel to the cylindrical roller rotation axis in the vertical direction longitudinally displaceable relative to the ground, however, is or are guided non-rotatably. The synchronous drive of the cylinder roller is effected by a central electric motor which synchronously drives the cylinder rollers via shafts, angular gear and further shafts and angle gear arranged below a frame. The speed and acceleration characteristics of the lifting movement as well as the position of any standstill points of a lifting platform is determined by the course of the control grooves of the rollers. For this purpose, a control pin engages in the relevant groove. If two or more linear actuators of this type are to be used for the lifting drive for the lifting platform, care is taken by suitable measures, for example an additional geared coupling of the angular gear, to ensure that a synchronous running of the driven cylindrical rollers is ensured.

The DE 102 17 064 A1 describes a so-called post lift with a control device and at least one support column, wherein the support column includes: a rotatably mounted lifting spindle with an external thread, controlled by the controller rotary drive for the lifting spindle, located with the lifting spindle in a supporting mother, by a rotational movement of the lifting spindle can be moved to a with the lifting spindle engaged catch nut, which is arranged offset to the support nut in the direction of gravity and runs along with the support nut, connected to the support nut lifting, on which at least one support arm is mounted, connected to the control device reference to Detecting an approach of the lifting carriage and a rotation monitor connected to the control device for detecting a rotational movement of the rotary drive, wherein each support column connected to the control means pulse counter for position monitoring of the Lifting carriage is assigned. The reference monitors and the rotary monitor can be designed as inductive proximity switches, wherein the rotary monitor can also be formed by an incremental encoder. As a result, a mother break monitoring device is provided with which a breakage of the support nut to be monitored. As soon as one of the rotary monitors detects no rotary movement when the rotary drive is switched on, the switch-off device switches off at least the relevant rotary drive and issues a corresponding warning message.

The DE 101 37 617 A1 relates to a method for starting up a positioning device with a drive motor for changing the position of a movable element, with an absolute encoder as a position sensor for detecting the actual position of the movable element and a position sensor for comparing the actual position with a predetermined desired position and the appropriate Control of the drive motor, wherein for determining the size of the position change per increment of the absolute value encoder, a first and a second position are approached, wherein the respective position in a predetermined unit and the associated value of the absolute encoder are detected and stored and wherein the ratio of the differences of the two measured measured positions and the two detected values of the absolute value encoder, wherein the first or the second measured position as a reference point for the determination of the actual position in the predetermined unit of measurement based on the respective value of the Absolute encoder is selectable.

task

The invention has for its object to simplify a lift-lowering conveyor of the assumed genus and form less susceptible to interference.

solution

The object underlying the invention is achieved by the reproduced in claim 1 features.

Some advantages

The invention essentially involves the detection of the groove-roll movements by rotary encoders, constructed, for example, according to the induction principle or according to other principles, which precisely measures the position of the groove roll and an intermediate controller which evaluates these indications and with additional information of two initiators above and below the motor on command of the associated control on and off in the reached position again.

It is also possible to use sensors which can not detect multiple revolutions or lose this information when the power supply is switched off, or can not detect this information when switched off. Corresponding logic allows the controller to approach the lower point because the lower zero corresponds to the zero position of the sensor and the lower initiator is located within less than 360 ° before zeroing. The number of degrees from there to the upper zero point is programmed in the control at the device, so that this point can be approached immediately, as well as the upper initiator is disposed within less than 360 ° before the end of the roller groove.

As drive motor or motors preferably asynchronous motors, Schaltschüttgesteuert or FU-controlled, are used.

When the motor is switched off, the controller takes into account the required braking distance through a standard value and registers the stopping point reached. At each next operation, the braking point is corrected by the deviation of the stopping point from the setpoint. Brake wear is compensated. Advancing the braking point leads to a warning signal when the first limit value is reached ("End of locking angle" or "Renew brake") to the higher-level system PLC (Programmable Logic Controller, whereby the controller can also contain a control element). When a further limit value is reached, the control of the drive motor is blocked because the operation of the system is no longer safe. The control of the drive motor is possible again only after a so-called "reset" on the controller.

• – außer Sensoren keine beweglichen Teile,
• – robust, störunempfindlich,
• – verschleißfrei, wartungsfrei, selbstüberwachend,
• – vereinfachte Inbetriebnahme, keine Nockeneinstellung notwendig,
• – Entlastung der Anlagen-SPS, Steuerung findet nur in einer Schaltbox statt,
• – geringerer Verkabelungsaufwand (Initiatoren nur bis zur Schaltbox),
• – keine Störkanten, da der Sensor anstelle des beim Stand der Technik notwendigen Zahnritzels vorhanden ist und die Schaltbox (Steuerung) seitlich am Heber angeordnet sein kann,
• – Bremsverschleißkompensation,
• – geplante Instandhaltung möglich,
• – Sensor montiert auf der Nut-Antriebwelle eines Hebers,
• – zwei Initiatoren im Hebergehäuse zur Abfrage des Schlittens,
• – Steuerung am Hebergehäuse (oder leicht zugänglich in der Nähe),
• – robuste Technik mit Intelligenz übernimmt die komplette Hebersteuerung,
• – 80% Aufwands- und Zeitersparnis bei Installation gegenüber dem Stand der Technik,
• – ersetzt die herkömmliche Beschaltung mit Untersetzungsscheibe und Nocken.

In summary, the lift-lowering conveyor according to the invention has the following advantages:

• - no moving parts except sensors,
• - robust, insensitive to interference,
• - wear-free, maintenance-free, self-monitoring,
• - simplified commissioning, no cam adjustment necessary,
• - Relief of the plant PLC, control takes place only in a switch box,
• - lower cabling effort (initiators only up to the switch box),
• No interference edges, since the sensor is present instead of the pinion required in the prior art and the switch box (control) can be arranged laterally on the lifter,
• - brake wear compensation,
• - scheduled maintenance possible,
• Sensor mounted on the groove drive shaft of a lifter,
• Two initiators in the lifter housing for interrogating the carriage,
• - control on the lifter housing (or easily accessible in the vicinity),
• - Robust technology with intelligence takes over the complete lift control,
• - 80% cost and time savings in installation over the prior art,
• - replaces the conventional wiring with reduction disc and cam.

The travel of the lift-lowering conveyor can be, depending on the requirements, for example, between two 200 to 3300 mm, wherein the groove rollers z. B. in each case to 360 to 3600 ° turn.

In the invention, an inductive sensor is mounted with the actuator on the respective groove roller, that in the lower zero position of the groove roller of the inductive sensor is also in the zero position, the lower sensor is in the downward movement about 270 ° or less before reaching the zero position steams and remains this until the end of the movement, the signal from the sensor is linked to the evaluation by the inductive sensor (rotary encoder) and thus clearly gives the position below, the output "Position down" is set.

The upper zero position is defined by the programmable gradient, whereby the upper sensor is vaporized during the upward movement approx. 270 ° before reaching the upper zero position and this remains until the end of the movement. The signal from the sensor is evaluated by the inductive sensor (rotary encoder) linked and so clearly gives the position above, the output "position above" is set.

The two inductive sensors - top and bottom - are permanently monitored for correct function, whereby, for example, wire break with quiescent current monitoring, plausibility control is detected and in the event of a fault a system fault is signaled and the movement is stopped.

Other inventive embodiments

Further inventive embodiments are described in the claims 2 to 9.

Claim 2 describes the lifter motor with two speeds, being driven in normal operation quickly from one to the other position, and slowed down during manual operation or when driving.

According to claim 3, the optimization of the stop position is carried out only for normal operation, ie at fast, in the first movement is turned off 20 ° or at a value determined by testing before the lower / upper zero position, then continuously to the ideal zero position optimized, the Positions at the top and bottom are optimized separately.

According to claim 4 is initially continuously optimized to the ideal zero position with a window of +/- 1 °, this is shifted according to the turn-off, reaches the turn-off 25 °, the zero position window is extended to +/- 18 °, the stop position is on At the end of this window, the warning "end of trip" is generated and the corresponding output is set, then the switch-off angle may be shifted another five degrees, if the switch-off angle has reached the maximum permissible value of 30 °, the "system fault" and "end of snap-in angle" generated and set a corresponding output, the movements are disabled, a reset is necessary for further operation.

According to claim 5, the lifter is moved slowly, then turned off 10 ° or according to another determined by test value before the lower / upper zero position, it being assumed that no optimization is necessary here.

If position deviations of greater than 30 ° are detected, a malfunction is indicated after switching on (eg after disassembly) according to claim 6, in which case the upward movement is blocked, with the downward movement and reaching the lower zero position the fault is automatically canceled and the system is again referenced and ready for use.

Diagnostic and statistical data can be captured and stored.

According to claim 7, the drive rollers have an available Rastgang of 62 to 100 °, for the shutdown and optimization of the lower / upper zero position, this is virtually reduced to +/- 20 °, within this window, the position given down / up and the output " Position down / up "is set, this position is overrun, the error" Overflow down / up "is generated and the corresponding output set. The degree course from the lower to the upper position is basically known, since the travel of the lifter is stored in four digits in degrees in the device and thus gives the upper zero position. To set the number of degrees, the controller must be switched to the programming mode. This requires a switch with two positions, where position 1 corresponds to the operating mode and position 2 corresponds to the programming mode. In programming mode, the system fault is set and all movements are disabled. In addition, the programming mode is indicated by an LED next to the switch. Programming can be done via two methods. Variant 1 requires a separate software tool and a corresponding interface via the diagnostic interface (preferred variant). Should this not be available, this can also be done on the device with variant 2, and by means of the existing rotary switch is set successively, starting with the thousands position, the degree progression step by step. To do this, the setting of the rotary switch for each position is accepted by pressing the reset button. Each accepted position is indicated by a brief extinction of the LED.

If all four digits are programmed, the LED flashes at 10 hertz. Only now is the new Gradverlauf active and the programming can be terminated. If the programming mode is not ended properly or left prematurely, the old value remains active. It is also possible to teach-in. The programmed value must be in the valid range of 360 ° to 3600 °, on the other hand, in the operating mode, the system fault is set and all movements are disabled - Claim 8.

Claim 9 describes a lifting-lowering conveyor, in which designed as inductive sensors lower and upper sensors take into account disturbances such as broken wire through the plausibility check.

In the drawing, the invention is illustrated, for example. Show it:

1 a lifting-lowering conveyor in a schematic representation as a switching or control diagram;

2 a lift-lowering conveyor in a simplified side view, and

3 a control unit in a schematic representation.

With the reference numerals 1 and 2 are called lifters, which are arranged vertically and each have a groove roller 3 respectively. 4 ( 2 ) exhibit. The groove rollers 3 . 4 be by a common, for example, as an asynchronous motor via contactors or frequency converter designed drive motor 5 synchronously driven, such that a lift 6 ( 2 ), on which a skid with driven roller conveyor is arranged (not shown) in the direction X or Y, that is driven upwards and downwards without jerking. For this purpose, the lift engages 6 over the roller bolts 7 respectively. 8th in each case a groove 9 respectively. 10 the respective groove roller 3 respectively. 4 one. The grooves 9 and 10 form the movement sequence for the lift 6 As a rule, therefore, they do not have a constant gradient, but instead represent the acceleration and braking delays in such a way that the lifting platform 6 gently into their respective end positions - top and bottom - passes. For example, the lift is 6 by a Rastgang of the grooves 9 and 10 locked in the end position, so that the lift 6 can not unintentionally move under the influence of gravity in the direction of X, ie down.

The lift 6 Thus, in the X and Y directions, it performs a linear finite motion between the upper and lower positions. The travel can be, for example, between 200 and 3300 mm, with the groove rollers 3 and 4 z. B. between 360 ° and 3600 ° can rotate. Of course, deviations from these dimensions are possible depending on the operating conditions.

With the lift 6 are switching elements 11 and 12 connected, each having a top and bottom - end positions - arranged sensor 13 or 14 dampen and thereby mark the respective upper or lower position. The sensors 13 and 14 may be inductive sensors or sensors operating on other principles. The sensors 13 and 14 are z. B. on the lift 2 arranged immovable. Of course it is also possible, the sensors 13 and 14 with the switching elements 11 and 12 the lifter 1 assigned.

With 15 is referred to a sensor in the form of a rotary encoder, which operates, for example, according to the induction principle or other principles, the position of the groove roller 4 measures and an intermediate controller 16 ( 1 ), which evaluates this information and with the additional information of the two sensors 13 and 14 - above and below - the engine 5 controls and turns it on and off when reaching the upper and lower position. A corresponding logic allows the controller to approach the lower point, since the lower zero point of the zero position of the sensor 15 corresponds and the lower sensor 14 within less than 360 ° before zeroing. The number of degrees from there to the upper zero point, ie to the sensor 13 will be in the controller 16 programmed at the device, so that this point can be approached directly, as well as the upper sensor 13 within less than 360 ° before the end of the groove 10 the grooved roller 4 is arranged. The control 16 is with a memory programmable controller 17 (PLC) connected. The control 16 considered when switching off the engine 5 the required braking distance by a default value and registers the reached stopping point. At each next operation, the braking point and deviation of the stopping point from the set point are corrected. Brake wear is compensated. Bringing the braking point forward leads to a warning signal (eg end of locking angle or brake renewal) when the first braking value is reached, to the higher-level system PLC 17 , When a further limit value is reached, the control of the drive motor is blocked because the operation of the system is no longer safe. The drive of the drive motor is only after a so-called "RESET" on the controller 16 again possible.

LIST OF REFERENCE NUMBERS

1

Lift, lift tower

2

Lift, lift tower

3

Groove roll

4

Groove roll

5

drive motor

6

hydraulic ramp

7

roller pins

8th

roller pins

9

groove

10

groove

11

switching element

12

switching element

13

Sensor, initiator

14

Sensor, initiator

15

Sensor, rotary encoder

16

control

17

PLC, memory programmable controller

X

Lifting direction of the lift 6 downward

Y

Lifting direction of the lift 6 up

Claims (9)

Lift-lowering conveyor with vertically arranged lifters ( 1 . 2 ), each having a groove roller ( 3 . 4 ), which by a common drive motor ( 5 ) are synchronously driven via contactors or frequency converters, such that a lifting platform ( 6 ), on which a carrier, which may be a Skid, is arranged with a driven roller conveyor, can be driven without jolts upwards and downwards, wherein the lifting platform ( 6 ) via roller bolts ( 7 . 8th ) in each case a groove ( 9 . 10 ) of the respective groove roller ( 3 . 4 ), wherein the grooves ( 9 . 10 ) the movement sequence for the lift ( 6 ), such that the lift ( 6 ) in their respective end positions - top and bottom - passes gently, the lift ( 6 ) by a Rastgang the grooves ( 9 . 10 ) is locked in the respective end position, characterized by one or more rotary encoders ( 15 ), the or the rotational position of one or both rollers ( 3 . 4 ) and with an intermediate controller ( 16 ), which contains the information of the rotary encoder ( 15 ) or the encoder and with additional information of one upper and one lower sensor ( 13 . 14 ) trained initiator the engine ( 5 ) on command of the higher-level plant PLC ( 17 ) and switches off again in the reached stroke position, wherein the rotary encoder designed as an inductive sensor ( 15 ) so at the associated grooved roller ( 4 ) is arranged such that in the lower zero position of the grooved roll ( 4 ), wherein the term zero position refers to a rotational position, this encoder is also in the zero position, wherein the lower sensor ( 14 ) during the downward movement of the lift ( 6 ) before - 270 ° or less before reaching the Zeroing - by a on the lift ( 6 ) arranged switching element ( 12 ) is damped and remains vaporized until the end of the movement, whereby that of the lower sensor ( 14 ) outgoing signal together with that from the encoder ( 15 ) sent signal to the controller ( 16 ) and thus unambiguously determines the lower position, and the upper zero position is defined over a programmed degree course, wherein the upper sensor ( 13 ) during the upward movement of the lift ( 6 ) before - 270 ° before reaching the upper zero position - is damped and until the end of the lifting movement of the lift ( 6 ) remains vaporized, and that from the upper sensor ( 13 ) outgoing signal with the evaluation of the rotary encoder ( 15 ) together to the controller ( 16 ) and so clearly determines the upper position, and designed as inductive sensors lower and upper sensors ( 13 . 14 ) are controllable for disturbances by a plausibility check and in case of disturbances the movement of the lifting platform ( 6 ) is stoppable, so the controller ( 16 ) when switching off the engine ( 5 ) takes into account the required stopping distance by a standard value and registers the stopping point reached, wherein at each next operation the braking point and a deviation of the stopping point from the target value are automatically correctable and a brake wear is compensated. Lift-lowering conveyor according to claim 1, characterized in that the engine ( 5 ) is drivable with two speed ranges, and in the normal case can be moved quickly from one to another stroke position, while he is manually or in case of driving interruption on low speed switchable. Lift-lowering conveyor according to claim 1 or one of the subsequent claims, characterized in that the optimization of the stop position above and below only for normal operation takes place, for. B. is switched off when driving fast in the first movement about 200 ° or at a value determined by test before the lower or upper zero position, then it is optimized to the ideal stop position, such that the stop positions of the upper and lower strokes of the lifting table ( 6 ) can be optimized separately. Lift-lowering conveyor according to claim 3, characterized in that first continuously optimized to the ideal zero position with a window of +/- 1 °, then the switch-off angle is accordingly shifted, reaches the turn-off about 25 ° or the like, the zero Position window is extended to +/- 18 °, the stop position is at the end of the window, if the warning "End stop" is generated and the corresponding output is set, then the switch-off angle is shifted another five degrees, the switch-off angle has the maximum permissible value of 30 °, the warning "System fault" and "End of locking angle" is generated and the movements are blocked. Lift-lowering conveyor according to claim 1 or one of the subsequent claims, characterized in that when slow driving the lift ( 6 ) ten degrees or, at a number of degrees determined by test, before the lower or upper zero position of the drive motor ( 5 ) is switched off. Lift-lowering conveyor according to claim 1 or one of the subsequent claims, characterized in that position deviations of greater than 30 ° lead after switching on to fault messages, in which case the downward movement of the lift ( 6 ) is disabled, and when the lower zero position is reached, the fault is automatically cleared and the system is made operational again. Lift-lowering conveyor according to claim 1 or one of the subsequent claims, characterized in that the groove rollers ( 3 . 4 ) each have a Rastgang of, for example, 62 to 100 degrees, for the shutdown and optimization of the lower and upper zero position, this can be virtually reduced to +/- 20 °, and within this window, the position down / top given and the output " Position down / up "is set, whereby when overrunning the positions the fault" Overflow down / up "can be displayed. Lift-lowering conveyor according to claim 1 or one of the subsequent claims, characterized in that the degree course of the lower stroke position of the lift ( 6 ) to the upper position, the travel distance of the lift ( 6 ) four-digit in the control ( 16 . 17 ) is storable and thus, for example, gives the upper zero position, wherein for the adjustment of the number of degrees, the control is switched to the programming mode, wherein a switch with two positions is provided which has a position "operating mode" and a second position "programming mode", wherein in the programming mode, all movements are disabled and additionally by an LED this is displayed next to the switch, the programming is set either by a separate software tool and a corresponding interface via a diagnostic interface or by means of a rotary switch successively starting with the thousands digit the degree curve step by step , and the setting of the rotary switch for each position is adopted with the pressing of a RESET button, each taken place can be displayed by a brief extinction of the LED, after programming all four digits the LED flashes with, for example, 10 Hertz and da after the new gradient is active and the programming is finished or instead of programming via a rotary switch the upper position by control (teach-in) can be determined, and if not properly programming the old values remain actively stored, the programmed value is in the valid range of, for example, 360 ° to 3600 °. Lift-lowering conveyor according to claim 1 or one of the subsequent claims 2-8, characterized in that the detected by the plausibility control disorder is a wire breakage.

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