DE29502273U1 - Gearbox with automatic safety gear - Google Patents

Description

Gearbox with automatic safety gear

The invention relates to a transmission with an automatically acting safety device (locking device) according to the features of the preamble of claim 1.

Such gears are preferably used for direct drives of roller doors, rolling grilles and the like. The safety device ensures that a locking member is brought into engagement, thereby preventing the driven component from continuing to rotate due to inertia or gravity if gear damage occurs, for example as a result of gear wear.

DE 22 22 503 C describes a direct drive for roller doors in which an output worm gear and an auxiliary worm gear are connected to one another in a rotationally fixed manner. The drive worm that drives the output worm gear drives an axially displaceable auxiliary worm via another gear, which runs freely and meshes with the auxiliary worm gear with practically no torque transmission. As the gear wear of the drive worm/output worm gear pair increases, the auxiliary worm shifts slightly in the axial direction. In the event of gear damage, the output worm gear is prevented from continuing to rotate unintentionally by the auxiliary worm disengaging from its rotary drive through a larger axial movement and bringing the output worm gear to a standstill by self-locking with the auxiliary worm gear.

D-40239 DÜSSELDORF · MULVANYSTRASSE 2 ■ TELEPHONE 49 / 211 / 9S 145 - 0 · FAX 49/211/96 143 - 20

DE 31 29 648 C2 discloses a gear with an automatic safety catch, in which an output worm gear and an auxiliary worm gear are connected to one another in a rotationally fixed manner and are driven in rotation by one and the same drive worm. When the gear pair of drive worm/output worm gear becomes increasingly worn, the auxiliary worm gear is intended to stop the rotation drive by self-locking with the drive worm or by axial displacement and blocking engagement with the housing.

Finally, a generic gearbox with an automatic safety catch is known from DE 24 60 585 A1, in which the output worm gear accommodates a spring-loaded, axially movable bolt, which is held in a retracted position against the spring pressure during normal operation by an auxiliary worm gear driven by the drive worm. If a twist occurs between the output worm gear and the normally freely rotating auxiliary worm gear due to tooth wear of the drive worm/output worm gear pair, the locking bolt is released in its retracted position. The locking bolt then springs forward under spring pressure and engages in one of the locking recesses provided around the circumference of the gearbox frame.

The disadvantage of these known safety catches is that they only trigger when the gears are largely destroyed. Opening and closing the roller door or roller grille is not possible once the safety catch has been triggered.

Based on this, the invention is based on the object of creating a safety device in which the door drive is stopped before the gearing is destroyed, but which also ensures a reliable safety process if the gearing or the worm shaft breaks.

This object is achieved by the characterizing features of claim 1.

Further training is listed in the subclaims.

In normal operation, i.e. when the wear condition is not a concern, the catch element has no contact with the groove on the housing. If the gear teeth wear, the predetermined angular position between the output shaft and the auxiliary worm gear changes and the catch element pivots into the groove and touches the plastic ring, which is taken along with it if the wear continues. This rotation pushes a switching pin out of the housing, which interrupts the control voltage via a switch. This switch remains in the open position after being operated once.

By changing the inner diameter of the plastic ring arranged in the groove, the permissible wear value can be adapted to different gears. This means that in the majority of cases of wear, the safety device according to the invention will stop the door drive before the gears are destroyed. This means that the operator has the option of continuing to open or close the door using a hand crank (emergency hand chain or similar) until the gear has been replaced.

The actual catch only occurs when, for example, a toothing that is not yet worn breaks due to a material defect or overload. In this case, the catch element is pressed deeper into the groove, whereby according to a further development of the invention, the width of the catch element is larger than the width of the groove, so that the catch element is pressed into the narrower groove and removes chips from the groove flanks on both sides. The kinetic energy is thus converted into machining work. By using different dimensions of the catch element and the groove, the braking effect of the catch element can be precisely adjusted due to different machining work in the event of a catch.

In a preferred embodiment, the catching element has a width of 4 mm and the groove has a width of 3 mm, so that a chip of up to 0.5 mm width is removed on both sides. If the teeth break, the ring, which is preferably made of plastic, does not prevent the catching device from being switched on, since the tip of the catching element deforms the plastic ring. - It goes without saying that this catching device can also be used effectively without the rotatable ring and the drive shutdown caused by it.

Further details, features and advantages of the subject matter of the invention emerge from the following description of the accompanying drawing, in which a preferred embodiment of the invention is shown. In the drawing:

Fig. 1 a gearbox with an automatic safety gear in a layered view, perpendicular to the output shaft (section along the line I-I according to Fig. 2);

Fig. 2 the same gearbox in an axial section through the output shaft (section along the line II-II according to Fig. 1) and

Fig. 3 the same gearbox in a second sectional view, perpendicular to the output shaft (section along the line III-III according to Fig. 2);

Fig. 4 the same view as in Fig. 3 when wear occurs;

Fig. 5 the same view as in Fig. 3 when the fall arrest occurs, and

Fig. 6 A, the gearbox according to Fig. 1 in enlarged scale B + C representation in detail.

The gear unit, designated 100 in its entirety, consists of the main elements drive member 10, output member 20, frame member 30, locking member 40 and auxiliary gear ring 50.

The drive member 10 has a drive shaft 11 and is provided with a drive toothing 12 such as a drive worm 6.

The output member 20 has an output shaft in the form of a hollow shaft 3 and is provided with an output toothing 21 that meshes with the drive toothing 12. The latter is located in the illustrated and thus preferred embodiment on the outer circumference of an output worm gear 4 that is connected in a rotationally fixed manner to the hollow shaft.

The locking member, generally designated 40, has a catch element 41 that can be pivoted to a limited extent by means of a stop 41A, which is held pivotably by a bolt 5 that is connected to the output worm gear 4. The catch element 41 has on its edge a recess 42 into which a guide bolt 7 engages, which is connected to the auxiliary worm gear 2.

In the event of a rotation between the output worm gear 4 and the auxiliary worm gear 2, the catch element 41 pivots with its edge 43 into a groove 45 arranged in the housing 1, in which a plastic ring 46 is rotatably held and which, by means of a switching bolt 47 engaging in a recess 46A, opens or closes an emergency stop switch (interruption contact 48) in the event of a rotation with respect to the groove 45.

Figure 4 shows the position of the catch element 41 when wear has begun. The catch element 41 touches the plastic ring 46 in the groove 45 with the edge 43. The plastic ring is rotated within the groove and pushes a bolt 47 out of the housing 1, which interrupts the control voltage of the drive motor via the interrupt contact 48. The interrupt contact 48 remains in the open position after being actuated once. By varying the size of the inner diameter of the plastic ring 46, the triggering of the interrupt contact 48 can be adjusted to the permissible

•••6»

or desired wear value of the gear teeth.

Figure 5 shows the position of the catch element 41 when the catch occurs. As explained above, the catch element 41 is wider than the groove 45. In this embodiment, the 4 mm wide catch element 41 is pressed into the 3 mm wide groove 45 (the plastic ring 46 is deformed at the same time) and removes a chip of up to 0.5 mm width on both sides. A stop 4IA acting between the catch element 41 and the output shaft limits the swivel angle of the catch element 41 in particular in such a way that its edge 43 cannot touch the bottom of the groove 45. This swivel limitation thus prevents the catch element 41 from penetrating deeper into the groove 45 in the event of a catch than its flange depth T.

Figure 6 A-C shows the change in the groove 45 in a sectional view perpendicular to Figures 3 to 5. Figure 6 A shows normal operation, i.e., wear condition = 0. The catch element 41 rotates freely with the auxiliary worm gear 2. The groove flanks of the groove 45 are bevelled in the upper area in such a way that an extension 45A of the groove 45 results. In the example shown, the groove 45 has a width of 3 mm, which widens to 5.2 mm. The catch element 41 is 4 mm wide.

Figure 6B shows the wear position according to Figure 4. The catch element 41 is in contact with the plastic ring 46 located in the groove 45. Due to the extension 45A, the catch element 41 does not yet touch the groove flanks of the groove 45.

Figure 6C shows the catching position according to Figure 5. The plastic ring 46 is crushed and the kinetic energy is converted into cutting work. When the 4 mm wide catching element 41 engages in the 3 mm wide groove

45 resulted in a widening of the groove to 3.89 mm due to machining. By limiting the swivel angle of the catch element 41, the distance to the base of the groove 45 is 0.5 mm.

List of reference symbols:

1 housing

2 Auxiliary worm gear

3 Hollow shaft

4 Output worm gear

5 bolts

6 Drive worm

7 guide bolts

10 Drive link

11 Drive shaft

12 Drive gearing

20 Output link

21 Output gear 30 Frame member

40 locking link

41 Catch element 4IA stop A

42 recess

43 Edge

45 groove

45A extension

46 Plastic ring 46A Recess

47 Shift bolt

48 switches

50 Auxiliary gear ring

51 Gearing

T flank depth

Claims (3)

1. Gearbox with self-acting safety device (locking device) for direct drives of e.g. roller doors, rolling grilles, lifted loads or the like, comprising at least a drive member (10) ₇ an output member (20), a frame member (30), a locking member (40) and an auxiliary gear ring (50), in which a) the drive member (10) has a drive shaft (11) with drive teeth (12), such as a drive worm (6), b) the output member (20) has an output shaft, such as a hollow shaft (3), with an output toothing (21) meshing with the drive toothing (12), such as an output worm gear (4) connected to it in a rotationally fixed manner, c) the frame member (30) has bearing surfaces for a rotary bearing of the drive member (10), the driven member (20) and the auxiliary gear ring (50), d) the auxiliary gear ring (50) with a toothing (51) like an auxiliary worm gear (2) meshes with the drive toothing (12) and the auxiliary gear ring (50) and the driven toothing (21) can be rotated relative to one another while triggering the locking engagement, e) the locking member (40) causes a blocking of the output shaft in the event of a change in position between the drive worm gear (6) and the auxiliary worm gear (2), characterized in that a catch element (41) is held by a bolt (5) connected to the drive worm gear (4), a guide bolt (7) connected to the auxiliary worm gear (2) engages the catch element (41) in such a way that in the event of a rotation between the driven worm gear (4) and the auxiliary worm gear (2) D-40239 DÜSSELDORF ■ MULVANYSTRASSE 2 · TELEPHONE 49 / 211 / 96 145 ■ 0 ■ FAX 49 / 211 / 96 145 - 20 an edge (43) or a projection of the catch element (41) in or in the direction of a groove provided in the frame member (30) (45) pivots, and that a ring, preferably made of plastic material, rotatably arranged in the groove (45) (46) can be rotated from the edge or projection of the catch element (41) and, in the event of rotation, actuates an interruption contact (48). 2. Gear according to claim 1, characterized in that the width of the catch element (41) is designed to be larger than the width of the groove (45) in such a way that when the edge or the projection of the catch element (41) penetrates into the groove (45), the flank areas of the groove are machined. 3. Gear according to claim 1, characterized in that a pivot limiting means (41A) for the catch element (41) prevents the catch element (41) from penetrating deeper into the groove (45) than its flank depth (T) in the event of a catch.