EP2520534B1 - Load detection device for lifting devices and electric chain hoists - Google Patents

Description

The invention relates to a device for load detection on hoists and electric chain hoists according to the preamble of claim 1, which comprises at least one in operative connection with a drive motor and engaged with a support means output shaft which is rotatably mounted within a housing using at least one housing bearing.

An electronic load detection is according to the definition of EN 14492-2 an indirectly acting lifting force limiter. It represents a possible solution for detecting overload and underload conditions of a hoist. The electronic load detection can be used as a stand-alone solution or as a supplement to direct Hubkraftbegrenzern, such as slipping clutches.

From the prior art as well directly acting Hubkraftbegrenzer are already known in the form of slip clutches according to the EN14492, which lie in power flow with driven device and allow occurring overloads by overcoming the static friction between the coupling halves relative movement of the coupling halves and thus overloading the drive train prevent. When the device is braked, the slip clutches may be in the force flow, but in the case of hoists, preferably outside the force flow. The friction clutch protects the gear parts and the drive motor of the hoist from overload due to shock and overload. The slip clutch is also suitable for use as a lifting and lowering limiter. A disadvantage of the direct acting Hubkraftbegrenzer is to mention that via slip clutches adjustable triggering values for the overload are inaccurate due to the physical dispersion of the adhesive and sliding friction values. This effect is possibly enhanced by the scattering of the forces of the spring elements used. In addition, slip clutches subject to design-related wear. They must be monitored in use and readjusted if necessary.

The above-mentioned indirectly acting Hubkraftbegrenzer have in common that the overload is not detected directly in the load line, but detected by mechanical, electrical or electronic auxiliary structures and evaluated appropriately. Examples of this are Seilkraftbegrenzer, spring-loaded compensating pulleys, sprung torque arms, sprung load sensing frame or load sensing pin, load cells or Zugkraftaufnehmer to name with evaluation. A disadvantage of the previously known indirectly acting Hubkraftbegrenzern that the required for detecting an overload mechanical parameters outside the housing of the hoist or electric chain hoist are detected. This is always a mechanical connection, z. As a lever or a roller, or to provide an electrical connection in the form of a cable between detection location and evaluation on the hoist. By damaging the signal connection, the load detection can be ineffective.

In addition, it should be mentioned that in the previously known indirect Hubkraftbegrenzern internal overloads, which are caused for example by jamming of the suspension element in the housing of the hoist, can not be detected.

The DE 10 2005 049351 A1 discloses an electromechanical overload protection for electrically driven chain hoists or cables. This overload protection comprises an electric drive motor, a transmission and a mounted in a housing main output shaft with a load carrying the load chain sprocket or with a cable drum, wherein the drive motor is switched off in case of overload by means of limit switches. Characteristic of this invention, the main output shaft on the one hand in the housing fixedly arranged on the drive side with a angularly movable bearings and on the other hand mounted in the opposite housing wall with a movable towards the load bearing with an eleastischen, yielding or resilient bearing assembly or a bearing support and with a shaft extension with a shaft stub is provided, spaced from the bearing assembly or the bearing support to the stub shaft of the extended main output shaft, a switching device with limit switches engages, which is in a tilting movement of the main output shaft in overload in engagement with the stub shaft. The principle underlying this invention is an electromechanical shutdown. The bearing on the bearing carrier is resilient and allows a tilting movement of the output shaft. This tilting movement, ie a path, is detected mechanically and also mechanically converted into a switching path. Shutdown is via a mechanical switch or sensor.

In the WO 2006/018276 A1 is a hoist with a drive motor, with a gear housing to which the drive motor is flanged, in which the motor shaft protrudes and forms the opposite end shields containing bearing seats for shafts described. Furthermore, an output shaft is provided, which is mounted in the transmission housing and which projects at one end over one of the end shields, wherein by means of the projecting end a load-receiving means is driven. Also included is a sensor, which is arranged next to one of the bearing seats to there the to detect elastic deformation of the relevant bearing plate due to the load of the bearing receiving means. The operating principle underlying this hoist is an electronic load detection with sensor in the end shield. The elastic deformation of the end shield is detected and evaluated by a sensor. The end shield is instrumented with a sensor and its deformation is measured.

Ultimately be on the WO 02/02450 A1 referenced, in the subject invention, an electronic load detection with sensor in the camp of the cable drum comes as an active principle used. The elastic deformation of the bearing is detected and evaluated by a sensor.

The object of the invention is now to propose a device for load detection on hoists and electric chain hoists, which detects both external and internal overloads, which is virtually maintenance-free and by means of which a better utilization of the lifting height can be achieved.

According to the concept of the invention, the device for load detection on hoists and electric chain hoists comprises at least one output shaft which is in operative connection with a drive motor and in engagement with a suspension element, which is rotatably mounted within a housing using at least one housing bearing. According to the invention, the output shaft is additionally assigned a bearing carrier with bearings and at least one sensor operatively connected to a control, wherein the sensor is designed to detect either the forces acting on the bearing carrier or the deformation of the bearing carrier, and the signal detected by the sensor in the controller is evaluated, to ensure an emergency running the fully trained with a seal housing bearing has a bearing fit, which is formed on the one hand for defined introduction of force in the bearing carrier and on the other hand formed at breakage of the bearing carrier for receiving the bearing forces and introduction into the housing.

For the purposes of the invention, suspension means are wire ropes, chains or steel bands, the output shaft being designed as a chain shaft when chains are used. For this purpose, the housing of the device has an engagement point at which the selected suspension element engages positively or non-positively on or into the output shaft.

Depending on adjustable or defined load limit values, the output signal of the controller is used either for controlling the drive motor which is in operative connection with the output shaft and / or for the optical, acoustic or tactile perceptible display. Thus, for example, a monitor, a lamp, a horn, a vibration device or any other display can be used as the display, which signals the user to the corresponding state. As a result of the control of the drive motor, for example, in case of overload or jamming of the suspension means lifting or underload the lowering switched off or just this critical state to be displayed to the user for individual decision-making.

The term control is to be understood in the context of the invention as such a device, which signals of any kind can be supplied and which generates output signals. However, this device may also have at least one controller for forming a control to form a control difference between the input and defined parameters, for example, adjustable load limits.

The sensor may preferably be placed on the bearing carrier or in the bearing carrier. The locked using fasteners in the housing bearing carrier may preferably be formed as a support or as a cantilever.

In a further advantageous embodiment of the invention, the sensor is placed on the bearing or in the bearing of the bearing carrier.

It has proved to be particularly advantageous for structural reasons, if the bearing of the bearing carrier is designed as a rolling bearing.

Optionally, an amplifier downstream of the sensor and upstream of the controller is provided in the signal flow direction, the digital or analog output signal of which can be fed to the controller.

In a further advantageous embodiment of the invention, the sensor is in operative connection to the drive motor of the device that when approaching a lifting and / or Senkbegrenzers to the housing, the signal detected by the sensor supplied to the controller and the drive motor is turned off and / or an optical, acoustic or tactile perceptible display takes place. When approaching a lifting and / or Senkbegrenzers to the housing Thus, an emergency stop switch of the device can be realized in a particularly advantageous manner.

For the purpose of optimal power transmission and speed adjustment is preferably provided as an operative connection between the drive motor and the output shaft, a single or multi-stage transmission.

• die auf die Abtriebswelle des Hebezeuges bzw. Elektrokettenzugs einwirkende Kraft wird direkt detektiert und ausgewertet,
• die elektronische und/oder elektrische Lasterfassung kann genauer als eine Rutschkupplung eingestellt werden, unterliegt keinem Verschleiß und ist nahezu wartungsfrei,
• die äußere Kabelführung im Sinne einer Signalleitungsführung eines außerhalb des Gehäuses platzierten Sensors in das Gehäuse hinein entfällt, da die Lasterfassung durch den zumindest einen innerhalb des Gehäuses platzierten Sensors erfolgt,
• einfacher konstruktiver Aufbau mit hohem Vorfertigungsgrad ohne die Notwendigkeit, unmittelbar vor der Inbetriebnahme oder Inbetriebsetzung ergänzende Montageschritte, wie beispielsweise die externe Signalleitungsmontage vom Erfassungsort außerhalb des Gehäuses zur Steuerung bzw. Auswerteinheit durchführen zu müssen,
• zu den bislang nur äußeren Überlastungen der Vorrichtung können nunmehr auch innere Überlastungen, beispielsweise hervorgerufen durch eine Verklemmung des Tragmittels an der Abtriebswelle im Bereich der Eingriffsstelle des Gehäuses, detektiert werden.
• zur Erzielung einer diversitären Redendanz besteht die Möglichkeit, konventionelle Rutschkupplungen mit der erfindungsgemäßen Lasterfassung zu kombinieren,
• es ist nur eine Baugruppe für eine jeweils eine Gehäusegröße zu konstruieren und vorzuhalten, was zu einer effizienten Serienfertigung führt und
• die Möglichkeit der freien Kalibrierung der Lagerträger führt zu einem breiten Abschaltspektrum.

The significant advantages and features of the invention over the prior art are essentially:

• the force acting on the output shaft of the hoist or electric chain hoist is directly detected and evaluated,
• The electronic and / or electrical load detection can be set more precisely than a slip clutch, is not subject to wear and is almost maintenance-free,
• the outer cable guide is omitted in the sense of a signal line guide of a sensor placed outside the housing into the housing, since the load detection is effected by the at least one sensor placed inside the housing,
• simple structural design with high degree of prefabrication without the need to carry out additional assembly steps, such as the external signal line assembly from the detection point outside the housing to the controller or evaluation unit immediately before commissioning or commissioning,
• To the previously only external overloads of the device can now also internal overloads, for example, caused by a jamming of the support means on the output shaft in the region of the engagement point of the housing can be detected.
• In order to achieve a diversified speech, it is possible to combine conventional friction clutches with the load detection according to the invention,
• it is only an assembly to design and stock a housing size, resulting in efficient mass production and
• the possibility of free calibration of the bearing carrier leads to a broad shutdown spectrum.

Fig. 1:

einen Querschnitt der Vorrichtung und

Fig. 2:

eine Seitenansicht der Vorrichtung entlang des Schnitts A-A.

The objectives and advantages of this invention will become better understood and appreciated after a careful study of the following detailed description of the preferred non-limiting example embodiment of the invention, with the accompanying drawing, in which:

Fig. 1:

a cross section of the device and

Fig. 2:

a side view of the device along the section AA.

The Fig. 1 shows a cross section of the device for load detection of hoists and electric chain hoists in the form of an electric chain hoist. Such hoists are used, for example, in industry and in stage technology. The device shown comprises an output shaft 3, which is in operative connection with a drive motor, not shown, and in engagement with a support means, not shown, which is rotatably mounted within a housing 1 using two housing bearings. As an example for both housing bearings, a housing bearing is denoted by the reference numeral 7, which is arranged in the housing 1 in the region of the almost centrally arranged engagement point of the output shaft 3. Between the drive motor and the output shaft 3, not shown, a gear is usually placed, which is not shown for reasons of clarity. According to the invention, the output shaft 3 is additionally assigned a bearing carrier 4 with a bearing 8 designed as a roller bearing, on which the output shaft 3 is supported. In addition, a sensor 5, which is in operative connection with a control, not shown, is provided which is arranged directly on the bearing carrier 4. This accordingly arranged within the housing 1 sensor is the acting on the bearing support 4 forces or the deformation of the bearing support 4 is detected detected. The signal, which is preferably permanently detected by the sensor 5, is fed to the controller via signal lines, not shown, where it is correspondingly evaluated and optionally further processed. Depending on adjustable load limits, the output signal of the controller is used either to control the drive shaft 3 in operative connection with the drive shaft 3 and / or for the optical, acoustic or tactile perceptible display.
To ensure a runflat property, the completely formed with a seal 6 housing bearing 7 has a bearing fit, which is formed on the one hand for defined introduction of force in the bearing carrier 4 and on the other hand formed at breakage of the bearing support 4 for receiving the bearing forces and introduction into the housing 1.

The Fig. 2 illustrates a side view of the device according to the invention for load detection of an electric chain hoist along the section AA. While on the viewer's right side of the Fig. 2 the recording of the drive motor is indicated, can be on the left side of the Fig. 2 a detailed representation of the interaction of the sensor 5 and the bearing support 4 with the bearing 8 designed as a rolling bearing. The bearing carrier 4 with its bearing 8 is arranged in the region of one end of the output shaft 3. The structural design of the bearing carrier 4 is carried out in dependence on here not to be explained criteria. Preferably, however, the bearing carrier is designed as a cantilever or as shown here, as a carrier on two supports. The bearing carrier 4 is releasably locked in the housing 1 using two fastening means 9. The bearing forces received by the bearing 8 are transmitted to the bearing support 4 which at least partially contacts the bearing 8 and detected by the sensor 5. In addition, the sensor 5 is also able to detect even deformations of the bearing carrier 4. The skilled person is of course that as Sensor 5 any sensor can be used regardless of its structural design, its physical detection method or its arrangement, which is only able to detect forces, paths or possibly speeds.

LIST OF REFERENCE SIGNS

1

casing

2

housing space

3

output shaft

4

bearing bracket

5

sensor

6

seal

7

bearing Units

8th

camp

9

attachment points

Claims (9)

1. Load detection device for lifting devices and electric chain hoists, at least comprising an output shaft (3) operatively connected to a drive motor and engaged with a load carrying means, the output shaft (3) rotatively supported within a casing (1) using at least one casing bearing (7), wherein at least one bearing carrier (4) with bearing (8) is assigned to the output shaft (3) and at least one sensor (5) is provided operatively connected to a controller, with the sensor (5) established detecting either

   a. the forces acting upon the bearing carrier (4); or

   b. the deformation of the bearing carrier (4),

   the signal detected by the sensor (5) being evaluated in the controller characterized by that for ensuring an emergency running property the casing bearing (7), which is established completely provided with a sealing cover (6), has a bearing fit established, on the one hand, to definitely introduce forces into the bearing carrier (4) and on the other hand, if the bearing carrier (4) breaks, to accept the supporting forces introducing said forces into the casing (1).
2. Device to claim 1 characterized by that depending upon adjustable load limits the output signal of the controller is used either

   a. to control the drive motor that is operatively connected to the output shaft (3); and/or

   b. to produce an optical, acoustic or tactilely perceptible indication.
3. Device to claim 1 or 2 characterized by that the sensor (5) is placed at the bearing carrier (4) or in the bearing carrier (4).
4. Device to any of the claims 1 to 3 characterized by that the bearing carrier (4) arrested using fastening means (9) in the casing (1) is established as support or cantilever beam.
5. Device to any of the claims 1 to 4 characterized by that the sensor (5) is placed at the bearing (8) or in the bearing (8).
6. Device to any of the claims 1 to 5 characterized by that the bearing (8) is established as antifriction bearing.
7. Device to any of the claims 1 to 6 characterized by that in signal flow direction an amplifier is provided arranged following the sensor (5) and before the controller, with the digital or analog output signal of the amplifier being feedable to the controller.
8. Device to any of the claims 1 to 7 characterized by that the sensor (5) is in operative connection to the drive motor of the device such that when a lifting and/or lowering limiter approaches the casing (1) the signal detected by the sensor (5) is fed to the controller and the drive motor is switched off and/or an optical, acoustic or tactilely perceptible indication is produced.
9. Device to any of the claims 1 to 8 characterized by that a transmission is provided between the drive motor and the output shaft (3) as operative connection.

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