System arrangement of lifting mechanisms and method of operating the system arrangement

Abstract

A system arrangement for the drive train of lifting mechanisms, such as crane lifting mechanisms, is disclosed. The system arrangement includes at least one drive motor (1, 1), at least one cable drum (2, 2) connected thereto, a reduction transmission (3) arranged between the drive motor (1, 1) and the cable drum (2, 2), an automatic overrun shutdown freewheel (6), and at least one safety brake (4, 4). To optimize such a drive train, at least one active motor locking assembly (5, 5) is utilized to hold the load when the drive motor (1, 1) is decelerated electrically to a rotary speed of zero. The active motor locking assembly is utilized instead of at least one passive operating brake.

Claims

1. A system arrangement for lifting mechanisms comprising: at least one drive motor (1, 1); at least one cable drum (2, 2) connected thereto; a reduction transmission (3) arranged between the drive motor (1, 1) and the cable drum (2, 2); an automatic overrun shutdown freewheel (6); at least one safety brake (4, 4), and at least one active motor locking assembly (5, 5) to hold the load when the drive motor (1, 1) is slowed down; a stator ring gear (20) fixedly connected to a housing of the drive motor (1, 1), the stator ring gear (20) having a face tooth arrangement (21) operative in an axial direction; and a rotor ring gear (22) non-rotatably arranged on a motor shaft (15) of the drive motor (1, 1), the rotor ring gear (22) being axially displaceable thereon and having an equivalent face tooth arrangement (23); wherein the rotor ring gear (22) is coupleable to the stator ring gear (20) to lock the drive motor (1, 1).

2. The system arrangement of claim 1, wherein the motor locking assembly (5, 5) is a positively locking assembly.

3. The system arrangement of claim 1, wherein the motor locking assembly (5, 5) is a force-locking or frictionally-locking assembly.

4. The system arrangement of claim 1, wherein the motor locking assembly (5, 5) is hydraulically, electro-hydraulically, pneumatically or magnetically actuatable.

5. The system arrangement of claim 1, wherein the motor locking assembly (5, 5) is arranged jointly with a motor coupling (11, 11) between the drive motor (1, 1) and the reduction transmission (3).

6. The system arrangement of claim 1, wherein the motor locking assembly (5, 5) is arranged on a side of the drive motor (1, 1) facing away from the reduction transmission (3).

7. The system arrangement of claim 1, wherein the drive motor (1, 1) is flange-mounted directly to the reduction transmission (3) without interposition of a motor coupling.

8. The system arrangement of claim 1, wherein the rotor ring gear (22) is held in an uncoupled position via compression springs (24) and is displaceable in a direction toward the stator ring gear (20) to a coupled position, actuating the motor locking assembly (5, 5).

9. The system arrangement of claim 1, wherein the freewheel (6) is integrated into the reduction transmission (3).

10. The system arrangement of claim 9, wherein the freewheel (6) is arranged selectively on an input shaft (7), an intermediate shaft (8) or an output shaft (9) of the reduction transmission (3).

11. The system arrangement of claim 10, wherein a cable drum joint connection (10, 10) is provided between the output shaft (9) of the reduction transmission (3) and the at least one cable drum (2, 2), and the freewheel (6) is integrated into the cable drum joint connection (10, 10).

12. The system arrangement of claim 1, wherein the at least one safety brake (4, 4) is arranged in two independent control circuits (26, 27).

13. A method of operating the system arrangement of claim 1, comprising activating the motor locking assembly immediately after electrical deceleration of the at least one drive motor to a rotary speed of zero.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

(1) The foregoing summary, as well as the following detailed description of the invention, will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, there are shown in the drawings embodiments which are presently preferred. It should be understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown. In the drawings:

(2) FIG. 1 shows a first embodiment of the invention,

(3) FIG. 2 shows a second embodiment of the invention,

(4) FIG. 3 shows a third embodiment of the invention,

(5) FIG. 4 shows a fourth embodiment of the invention,

(6) FIG. 5 shows a view on an enlarged scale of a specific configuration of the motor locking means, and

(7) FIG. 6 shows another embodiment of the motor locking means.

DETAILED DESCRIPTION OF THE INVENTION

(8) Referring to the drawing the drive train according to the invention which is intended in particular for crane lifting mechanisms comprises two drive motors 1, 1, two cable drums 2, 2, a reduction transmission 3 disposed between the drive motors 1, 1 and the cable drums 2, 2, an automatic overrun shutdown means and two safety brakes 4, 4 fitted to the cable drums 2, 2.

(9) In addition the drive train according to the invention has active motor locking means 5, 5 which serve to hold the load in the event of the drive motors 1, 1 being electrically decelerated to the rotary speed 0 and which can be actively actuated. In that way it is possible to dispense with the per se known passive operating brakes normally arranged between the drive motors 1, 1 and the reduction transmission 3.

(10) Provided as the overrun shutdown means is a freewheel 6 which, in each of the embodiments by way of example shown in FIGS. 1 to 4, is integrated in the reduction transmission 3. In the illustrated examples the freewheel 6 is arranged on the input shaft 7 of the reduction transmission 3. Alternatively however the freewheel 6 could also be arranged on the intermediate shaft 8 or the output shaft 9 of the reduction transmission 3.

(11) In all four embodiments of the drive train according to the invention there is a cable drum joint connection 10 and 10 respectively between the output shaft 9 of the reduction transmission 3 and the respective cable drum 2 or 2. In the structure shown in FIG. 4 the freewheel 6 is integrated in the cable drum joint connections 10 and 10 respectively.

(12) In the embodiment shown in FIG. 1 the motor locking means 5 or 5 is arranged together with the motor coupling 11 or 11 between the respective drive motor 1 or 1 and the reduction transmission 3.

(13) FIG. 5 shows a partly sectional view on an enlarged scale of the motor locking means 5. In this embodiment the motor locking means 5 is of a positively locking configuration, more specifically in the form of a selector shift tooth arrangement. It comprises a stator gear 13 which is arranged on the housing 12 of the reduction transmission 3 and which projects from the housing 12 in the direction towards the drive motor 1 and is provided with an outside tooth arrangement 14. The shift tooth arrangement further includes a rotor gear 16 which is arranged non-rotatably on the motor shaft 15 or the input shaft 7 of the transmission and which is also provided with an outside tooth arrangement 17. A shift element 18 serves for coupling or uncoupling the two gears 13 and 16, the shift element 18 being provided with an inside tooth arrangement which fits with the outside tooth arrangements 14 and 17 of the gears 13 and 16.

(14) In the upper part FIG. 5 shows the uncoupled condition in which the shift element 18 is carried exclusively on the stator gear 13 so that there is no connection to the rotor gear 16. In the lower part of FIG. 5 the shift element 18 extends over the outside tooth arrangements 14 and 17 of both gears 13 and 16 so that the motor shaft 15 is blocked by means of the motor locking means 5.

(15) In the embodiment shown in FIG. 5 the rotationally fixed mounting of the rotor gear 16 is effected by way of a fitting key 19 which is fitted into corresponding grooves in the input shaft 7 of the reduction transmission 3 and the rotor gear 16. In addition the rotor gear 16 is connected non-rotatably and axially immovably to the motor shaft 15 by way of the motor coupling 11.

(16) In operation of the lifting mechanism the shift element 18 is held in its disengaged or uncoupled position by means of spring elements (not shown in the drawing). To produce the engaged or coupled position there is applied an active force which is produced in opposite relationship to the spring force and which can be produced by the most widely varying means, for example hydraulically or electro-hydraulically, pneumatically or also magnetically.

(17) In the embodiments shown in FIGS. 2 to 4 the motor locking means 5 and 5 is arranged on the side of the drive motor 1 or 1, that is remote from the reduction transmission 3.

(18) With such a structure, as shown in FIG. 3, the drive motor 1 or 1 can be flange-mounted directly to the reduction transmission 3 without the interposition of a motor coupling 11 or 11 respectively.

(19) FIG. 6 shows a specific configuration of this motor locking means as shown in FIGS. 2 to 4. As can be seen in detail, provided on the housing of the drive motor 1 is a stator ring gear 20 which is fixedly connected thereto and which has a face tooth arrangement 21 operative in the axial direction. Arranged on the motor shaft 15 is a rotor ring gear 22 which is displaceable axially thereon and which is arranged non-rotatably and which has an equivalent face tooth arrangement 23. The axially displaceable and non-rotational connection between the rotor ring gear 22 and the motor shaft 15 can be made by means of a fitting key or a taper profile (not shown in greater detail in the drawing).

(20) In the upper part of FIG. 6 the two ring gears 20 and 22 are shown in the disengaged or uncoupled position. That position is produced by means of compression springs 24 which in operation of the lifting mechanism hold the two ring gears 20 and 22 apart.

(21) In the lower part of FIG. 6 the two ring gears 20 and 22 are shown in the engaged or coupled position. To reach that locked condition there is provided an actuating device (not shown in the drawing) which presses the rotor ring gear 22 against the stator ring gear 20 in opposition to the compression springs 24. For uncoupling purposes the actuating device is moved back so that the rotor ring gear 22 is disengaged again by means of the compression springs 24.

(22) Therefore in normal operation, at the rotary speed 0 of the drive motors 1 and 1 respectively, the load can be held by means of the motor locking means 5 and 5 without the safety brakes having to operate so that the safety brakes are not stressed with high switching cycles. The drive train according to the invention therefore not only operates more reliably and more securely but also achieves a longer service life.

(23) In the embodiment shown in FIG. 4 there are two additional safety brakes 25, 25. The four safety brakes 4, 4 and 25, 25 can be actuated in paired relationship by way of separate control circuits 26, 27 so that this affords a redundant resource as an additional safety aspect.

(24) It will be appreciated by those skilled in the art that changes could be made to the embodiments described above without departing from the broad inventive concept thereof. It is understood, therefore, that this invention is not limited to the particular embodiments disclosed, but it is intended to cover modifications within the spirit and scope of the present invention as defined by the appended claims.