WO2009043324A1

WO2009043324A1 - Electric chain hoist having high lifting speed

Info

Publication number: WO2009043324A1
Application number: PCT/DE2008/001441
Authority: WO
Inventors: Matthias Hühn; Dietrich Hoffmann
Original assignee: Hoffmann Fördertechnik GmbH Wurzen
Priority date: 2007-10-02
Filing date: 2008-08-28
Publication date: 2009-04-09

Abstract

The invention relates to an electric chain hoist having a simple design and a higher lifting speed, comprising an electric drive motor, a gearbox, and an output shaft supported in a housing and comprising a chain sprocket and a load chain with the load. The electric chain hoist is characterized in that it has a manual gearbox (104) having a gear shift mechanism with at least two more gears for a higher chain speed compared to the main lift. In the case of larger lifting heights, a lighter load can be lifted with a higher lifting speed and a rotational speed exceeding the rated speed using accordingly smaller torque. Likewise, after lifting a heavy load to a large lifting height it is advantageous to return the load chain into the starting position with high speed. In addition, the starting gear step is provided with a lock, which secures the load (14) from being lowered during the shifting operation.

Description

Electric chain hoist with high lifting speed

The invention relates to an electric chain hoist with high lifting speed in which with an electric pole-changing drive motor for the fine stroke and the main stroke, a transmission and an output shaft mounted in a housing with a sprocket a load chain with the load is driven.

There are electric chain hoists known which are designed for a comparatively large, maximum lifting force. This maximum force is assigned a low lifting speed in the main stroke. This maximum lifting speed corresponding to the maximum force can not be further increased. The electric chain hoists feature pole-changing motors or speed-controlled motors for the fine lift to reduce the lifting speed. With the pole-changing motor, which has an additional winding for a second engine speed, the fine stroke is accomplished.

In DE 4434373 Al an electric train is described with speed-controlled lifting speed, which generally has a single speed for raising and lowering the load according to the rated speed of the motor and the selected gear ratio. If the speed and the motor speed are to be changed continuously, this is made possible by a static frequency converter, which converts the speed-determining fixed mains frequency into a rotating field with variably controllable frequency for the motor. The problem arises that the installation of a control electronics loss heat is generated, which can not always be dissipated to a sufficient extent.

Also known are cables or pulleys with a cable drum. The difference between a cable and the electric chain hoist is the simple and compact design of the electric chain hoist. This compact design is due to the fact that the load chain is directly driven by the load with a small diameter chain sprocket. A rope drum has a much larger drum diameter, because a wire rope can not bend arbitrarily. As a result, the load can not attack directly on the cable drum. The load is lifted by a pulley. Cables have a fine lifting gearbox to reduce the lifting speed. If the lifting speed is to be increased in a winch, two hoist winches and a single rope are used according to DE 1920660 Bl. In order to achieve different speeds or lifting forces in a winch, the number of cable strands of the pulley can also be increased by the shearing. The lifting speed is reduced accordingly at high loads. For large lifting heights cables are less well suited according to DE 202006002491 Ul, because a loosely wound in the idle stroke rope can not be loaded with a load. Cables have the serious disadvantage that a load-free wound rope is pulled and clamped when attaching a load in the pulley.

In contrast, the invention aims at a structurally simple electric chain hoist with a large lifting height and a higher lifting speed compared with the known electric chain hoists.

According to the invention the object is achieved in an electric chain hoist in that the electric chain hoist has at least four lifting speeds and a manual transmission with a gearshift with at least two or more gears for a higher chain speed compared to the main stroke.

Especially at high lift heights it is often desirable to lift a heavy load with a low rated speed and high torque. In contrast, it is desirable for large lifting heights to lift a lighter load with a higher lifting speed and a speed lying above the rated speed with a correspondingly smaller torque. Likewise, after lifting a load to a high lift, it is advantageous to return the load chain to the home position at high speed.

Gear shifts have been known for a long time. Although, for example, from DE 697 36 199 T2 and DE 866 840 C2 drum winches with different speeds and from DE 7317950 Ul heavy winches with mechanical gear change have long been known, it is not yet known that the proposal of a gearshift in an electric chain hoist would ever have been proposed or realized with a lifting chain. The proposed electric chain hoist allows in a structurally simple way the lifting and lowering of different loads with widely divergent lifting speeds. The extraordinary advantage of the electric chain hoist with a gearshift is that with a conventional electric chain hoist a much higher lifting speed when lifting light loads and lowering the load-free load chain from a very large lifting height can be achieved. Compared to conventional electric chain hoists, the lifting speed can not only be reduced in terms of control technology, but significantly increased. This is of particular advantage when relatively small loads are lifted relatively quickly to a lifting height of, for example, 150 m. When lifting heavy loads, the time for lowering the load chain is reduced.

Manual transmission simple design, such as manual, are usually switched at idle with interruption of the power flow, during the switching operation of the drive motor is separated by means of a clutch of the manual transmission. After switching, the drive motor is engaged again. In an electric chain hoist, idle shifting is problematic when power flow is interrupted, because the powertrain is at least loaded with the weight of the load chain. In particular, at high lifting heights, if with a manual transmission, a high lifting speed to be achieved, the use of a manual transmission due to the weight of a long chain is associated with disadvantages.

For fall protection of the load chain with the load when switching the electric chain hoist with a gearbox with a gearshift in the output gear stage with the output shaft with the sprocket and the load chain on a lock with which the load is secured during the switching operation to change the gears against a load reduction , Preferably, the lock is connected to the gearbox so that a load fuse can be automatically made during the switching operation. The electric chain hoist allows in this way a safe lifting of different loads at different lifting speeds and an automatic locking of the load line during the switching process to prevent fall of the load. The invention will be explained below with reference to an embodiment with reference to the drawings. Advantageous embodiments of the invention will become apparent from the dependent claims. In detail shows

Figure 1 is an electric chain hoist with a manual transmission, Figure 2 is an electric chain hoist with a Vorschaltgetriebe, Figure 3 is an electric chain hoist with a secondary, Figure 4 is an electric chain hoist with a manual transmission and Figure 5 shows the electric chain hoist of Figure 4 with an automatic locking of the load line in a schematic representation.

A schematically illustrated in Figure 1 electric chain hoist consists of a housing 101 and a laterally arranged on or in the housing 101 drive motor 102. The drive motor 102 is connected by means of its motor shaft 114 with a transmission input shaft 103 to a gearbox 104 with a gearshift with at least two or several gears for different chain speeds leads. The output stage of the gearbox 104 is connected to a main output shaft 105, on which the sprocket 106 is arranged with the load chain 107 with the load hook 108. The attachment of the chain hoist is done via a housing suspension, not shown, which is arranged on the upper side of the housing 101. The load chain 107 exiting at the bottom of the housing 101 is driven in a known manner with the sprocket 106.

The switching of the lifting speed from a slower to a faster lifting movement of the load chain 107 takes place with the gearbox 104. The gearbox 104 may be a gearbox with multiple gear sets that allow different gear ratios. The change gear can be equipped with a manual manual transmission, for example, if only two different lifting speeds are required. Furthermore, the manual transmission 104 may comprise an automatic change gear, in which the change of the lifting speeds is effected by actuators or a hydraulic system. The manual transmission 104 may be equipped with a corresponding clutch device to enable better shifting. Normally, special coupling devices are not required, because the switching can be made in the main not under load, but before or after completion of the lifting process. Actuating the gearshift to change gears during full traction is usually not required. As a manual transmission 104 can also be used with an automatic transmission with a planetary gear or a continuously variable transmission. In addition, instead of the manual transmission 104 of FIG. 2, the electric chain hoist may have an existing reduction gear 109 and a primary gear 110 or a secondary gear 112 according to FIG. In a primary gear 110, the conventional reduction gear 109 is extended by a Vorschaltstufe. In this case, between the transmission input shaft 103 and the motor shaft 114, an additional counter stage is attached. As a result, at least two different lifting speeds are possible. Finally, the conventional transmission can be equipped analogous to the counter stage with a secondary 112. As a secondary 112, for example, between the main output shaft 105 and a sprocket 113 inserted two-stage planetary gear is suitable. This results in the Feinhub four different lifting speeds.

In a commercial electric chain hoist, the standardized load capacity is, for example, 1000 kg with a lifting speed in the main stroke of 6 meters per minute and a fine stroke of 1.5 meters per minute. With a gearshift and a second lifting speed then a smaller load, for example of the order of 250 kg, can be lifted relatively quickly to 150 m in less than 10 minutes. Just as quickly, the lowering speed of the empty load hook 108 or the load-free load chain 107 can be increased by a multiple compared to the lifting speed at maximum load at a corresponding gear ratio with a third gear. By a relatively small additional effort, a significant increase in performance in the rapid transport of loads can be achieved in large lifting heights and a saving in working time when using the electric chain hoist can be achieved.

In an electric chain hoist with manual manual transmission according to Figure 4, the gearbox (104) on the engine side an input gear stage, which consists of an axially ersteckenden motor pinion shaft 1 and the gear 2 of the first gear stage. The gear 2 is axially positively connected and rotatably connected to a switching shaft 3. On the switching shaft 3, a gear block of a second switchable gear stage is arranged, which consists of the pinion gear 4 and the pinion 5. The pinion gear 4 is like the gear 2 rotatably and positively connected in the axial direction with the switching shaft 3. The pinion 5 is incorporated in the switching shaft 3. The switching shaft 3 with the pinion gear 4 and the pinion 5 form a switchable gear stage, which is mounted axially displaceable. The output gear stage of the gearbox 104 has a smaller gear 6 and a larger gear 7, which are mounted together on the gear shaft 10. The gear shaft 10 further includes a stub shaft 8, which protrudes from the gear cover 9 and described below.

Parallel to the transmission shaft 10 of the second output gear stage, the output shaft 11 with the sprocket 12 and the load chain 13 with the load 14 is arranged. The power transmission takes place via a gear set with a gear reduction, which consists of an output gear 15 on the gear shaft 10 and a larger rotatably mounted output gear 16 on the output shaft 11. The drive force is provided by a drive motor 18 arranged laterally on the housing 17. The drive motor 18 is connected to the motor pinion shaft 1 via the motor shaft 21 by means of a slip clutch 19.

At the desired fast speed, the shift shaft 3 is pushed with the large pinion gear 4 in the smaller gear 6. At the lower stroke speed, the pinion 5 is brought into engagement with the larger gear 7. In this case, the motor pinion shaft 1 with the gear 2 is constantly engaged, which slides axially during the switching movement in the tooth flanks. During the switching movement, the pinion gear 4 and the gear 6 come out of engagement until the pinion 5 of the shift shaft 3 with the transmission gear 7 is engaged. In this way, a gear with two gears is possible.

The operation of the gearshift takes place in the embodiment with a shift rod 22 and an acting on the shift shaft 3 shift claw 23. The switching can be performed by hand. The switching movement of the switching shaft 3 is effected by means of a sliding movement of the shift rod 22. On the shift rod 22 which is guided in a guide bush 24, the shift claw 23 is fixed, which engages in an annular groove 25 of the shift shaft 3 and thus enables the transmission of the switching movement to the shift shaft 3.

Furthermore, the shift rod 22 seen in the axial direction is provided on both sides with edge grooves 26 which allow a limitation of the switching movement. Between the edge grooves 26, a control cam 27 is arranged for the actuation of a plunger push button 28. The limitation of the switching movement is carried out by the plunger button 28 by means of the edge grooves 26. At the beginning of the switching movement of the shift rod 22, the plunger button 28 by the control cam 27th operated and interrupted the power supply of the electric chain hoist by means of the electric ram switch 28. Immediately upon interruption of the power supply acts the hoist brake 29, which comes into force in an electroless electric chain hoist. After completion of the switching operation, the plunger button 28 is closed in the region of the outer peripheral grooves 26 and the power supply of the electric chain hoist restored.

Due to the hoist brake 29 arranged on the motor side in conventional electric chain hoists, the holding brake for holding the load 14 during shifting of the gears with respect to the output shaft 11 is not effective and the power flow is interrupted. Since the switching movement must be carried out without danger even at low load 14 or at a high weight of the load chain 13 and the lifting means, a locking of the output gear stage is provided for automatic load protection. The locking of the output gear stage for automatic load protection can be carried out in various ways electrically, pneumatically or manually. According to the embodiment shown here, the locking of the output gear stage, for example, also be controlled electrically by means of the plunger button 28 and the control cam 27. Likewise, the electrical or pneumatic control of the lock can be combined for example with an electric or pneumatic actuator for the gearshift. However, the invention should not be limited to the aforementioned embodiments. Rather, various embodiments of the invention are possible within the scope of the claims.

In the embodiment of Figure 5, the locking of the output gear stage is combined with the manual gearshift of Figure 4, so that the load protection automatically with the operation of the shift rod 22 occurs.

The shift claw 23 connected to the shift rod 22 has on the opposite side of the shift shaft 3, a latching element with a toothing 31 which positively engages with a fixed to the transmission shaft 10 of the second output gear stage ratchet wheel 32 at the beginning of the shift operation and during the switching operation with the ratchet wheel 32 is engaged. Thus, the output shaft 11 with the sprocket 12, via the transmission shaft 10 with the output gear 15 and the rotatably mounted output gear 16 on the output shaft 11, automatically locked. The ratchet wheel 32 is rotatably mounted on the protruding from the gear cover 9 stub shaft 8 of the transmission shaft 10 of the output gear stage. The ratchet wheel 32 is designed in its outer contour so that it easily rotates angularly into the teeth 31 of the shift claw 23 with a small circumferential clearance. At the same time a handwheel 33 is provided in the extension of the stub shaft 8. The hand wheel 33 can be moved during the switching operation in the circumferential direction. Thus, the gear pairs to be switched are adjusted during shifting. Since the shift claw 23 is immovable in the circumferential direction, a locking of the set of teeth with the output gear 15 on the transmission shaft 10 and the larger rotationally fixed output gear 16 on the output shaft 11 results in a load crash during the switching process is completely excluded.

Claims

claims

1. electric chain hoist with high lifting speed, in which a load chain is driven with the load with an electric pole-changing drive motor for the fine stroke and the main lift, a gearbox and an output shaft mounted in a housing with a sprocket, characterized in that the electric chain hoist at least four lifting speeds and a manual transmission (104) or a Vorschaltgetriebe (110) or a secondary transmission (112) having a gearshift having at least two or more gears for a higher chain speed with respect to the main stroke.

2. Electric chain hoist according to claim 1, characterized in that the manual transmission (104) of the electric chain hoist an input gear stage, a switchable gear stage and an output gear stage with the output shaft (11) with the sprocket (12) and the load chain (13), wherein the Output gear stage is provided with an electrically, pneumatically or manually actuated lock, with which the load (14) is secured during the switching operation against a load reduction.

3. electric chain hoist according to claim 1 to 2, characterized in that the electrically, pneumatically or manually operated locking the output gear stage is combined with an electric, pneumatic or manual actuator for the gearshift.

4. electric chain hoist according to claim 1 to 3, characterized in that the switchable gear stage comprises a manually operable shift rod (22) which is operatively connected to the locking of the output gear stage, that the load protection automatically with the actuation of the shift rod (22) occurs.

5. Electric chain hoist according to claim 1 to 4, characterized in that the motor-side input gear stage has an axially ersteckende motor pinion shaft (1) in engagement with the gear (2) of the first gear stage, which together with a pinion gear (4) and the pinion ( 5) axially positively connected and non-rotatably connected to a shift shaft (3) and optionally with a smaller gear (6) and a larger gear (7) of the transmission shaft (10) of the output gear stage is engaged, by means of an output pinion (15) on the transmission shaft (10) and a larger rotationally mounted output gear (16) on the output shaft (11) is connected on the output side, wherein for the operation of the switching shaft (3) an axially displaceable shift rod (22) is provided with a shift claw (23) which engages in an annular groove (25) of the shift shaft (3).

6. electric chain hoist according to claim 1 to 5, characterized in that seen in the axial direction, the shift rod (22) is provided on both sides with edge grooves (26) for limiting the switching movement, wherein between the edge grooves (26) of the shift rod (22) has a control cam (27 ) is arranged for the operation of a plunger switch (28) for the interruption of the power supply and the triggering of the normally acting hoist brake (29) of the electric chain hoist during the switching operation.

7. electric chain hoist according to one of claims 4 to 6, characterized in that the switching rod (22) connected to the switching claw (23) on the opposite side of the switching shaft (3) has a latching element with a toothing (31), the form-fitting with a on the gear shaft (10) of the second output gear fixed fixed ratchet (32) during the switching operation is engaged.

8. electric chain hoist according to one of claims 4 to 7, characterized in that the ratchet wheel (32) on a protruding from the gear cover (9) stub shaft (8) of the transmission shaft (10) of the output gear stage is rotatably mounted.

9. electric chain hoist according to one of claims 4 to 8, characterized in that the ratchet wheel (32) is designed in its outer contour so that it engages with a small circumferential clearance in the toothing (31) of the shift claw (23).

10. electric chain hoist according to one of claims 4 to 9, characterized in that in the extension of the stub shaft (8) a handwheel (33) is provided for Eiηjustieren the gear pairings when switching.