DE2737433A1 - Lift car safety braking device - has journalled shaft, drive wheel fixed and movable discs and centrifugal element - Google Patents

Abstract

A safety braking device for a unit movable along a surface, in partic. for a lift car, comprises a case which may be fixed to the moving unit. In the case there is journalled a shaft carrying at one end, outside the case, a drive wheel in slip-free engagement with the surface fixed discs integral with the case, and interposed between movable discs integral with the shaft. Means for axially urging together the discs comprises a screw thread in engagement with a screw thread integral with the movable disc, toothing and a toothed support member mesh with the toothing and carrying a centrifugal element adapted to engage an abutment which is fixed relative to the case.

Description

Safety brake for sliding along a surface

Means of transport, especially for elevator cars Present The invention relates to a safety brake that is designed to be mounted on a Is intended and is intended to slow down the means of transport sliding along the surface, as soon as it exceeds a specified speed. The invention is suitable especially for elevator cabins, scaffolding lifting devices or the like. she specifically relates to braking devices consisting of a housing attached to the Conveyor can be mounted and in which a shaft rotates, the outside of which the end of the housing is a cross without sliding effect on said surface Drive wheel and which carries a centrifugal element within the housing. The establishment is also with a fixed brake shoe connected to the housing and a movable one Brake shoe fitted, which gradually under the action of an axial screw connection is pressed against the stationary brake shoe, while the centrifugal element applied to a stop in its hadial plane.

Patent Fit 1,521,998 shows such a device. At this known device, the two brake shoes form a conical brake drum. The stop sits on the movable brake shoe in which the shaft can move freely is mounted; the shaft settles in a threaded extension fort that into a firmly connected to the housing and provided with an internal thread Sleeve engages. Once the centrifugal element that consists of a mounted on the shaft If the articulated arm hits the stop, it moves the movable brake shoe into a rotary motion, thereby extending this movable brake shoe screwed into the socket with internal thread and thus against the fixed Brake shoe presses.

Such a device has major disadvantages both brake shoes as long as the centrifugal element does not hit the stop - d. H. in the normal state of rest - in contact with each other, but not against each other movable. This results in considerable changes in the heat coefficient over time those brake shoes that turn out to be unpredictable Way, e.g. 13th due to fluctuating atmospheric conditions. When the safety brake If it should then work, nothing can guarantee the effectiveness of the braking will. In addition, the centrifugal element itself displaces the movable brake shoe rotating to apply the brakes. So it has all of the required withstand braking torque, which is why it must be made excessively large, what is inconsistent with the high sensitivity required for this element. if finally, after applying the brake, it stopped rotating If the centrifugal element is released from the stop, the shaft is released and the means of conveyance are released starts up again until the next action on the stop by the centrifugal element, which abruptly brings the shaft together with an already fully tightened brake; there is a risk that the device will break.

The purpose of the invention is a safety braking device that this Eliminates disadvantages easily and economically and even after a long period of inactivity a safe and permanent braking of the means of transport is still guaranteed.

The invention therefore has a device of the aforementioned type for Object which is characterized in that the movable brake shoe slides is keyed on the shaft and the stop is designed so that its Loading by the centrifugal element the displacement (by sin screws) of the movable brake shoe by an axial pressure element in weighting on the stationary Brake shoe causes.

With this type of construction, the movable brake shoe is set in rotation, as soon as the elevator starts, there is a slight, continuous mutual friction causes; in that the centrifugal element does not directly contact the movable brake shoe drives, but an axial pressure element of this brake shoe against the stationary one Brake shoe is pressed, this Zeotrifugal- Element that Braking torque not to be absorbed. Therefore it can be a very economical and highly sensitive one Centrifugal element with small dimensions can be used.

In a preferred embodiment of the invention, there are brakes shoes made of radial discs. Thus, the reveal surfaces are flat, which means that the two Fleming shoes cannot jam before the centrifugal element against the Stop bumps.

It is advantageous if the stop is attached to the housing and the centrifugal element is seated on a holding part that is in frictional contact with the Shaft mounted and provided with a gear, the axial pressure element from consists of a screw that is freely movable through the movable disc and on the end of which a drive wheel engaging the gear wheel is screwed. This is a particularly simple and effective embodiment of the axial pressure element.

Further features and advantages of the invention are evident from the following Description given as a non-limiting example only, as well as from the attached drawings.

Fig. 1 is a schematic elevation of an elevator car equipped with a Safety brake is equipped according to the invention; Fig. 2 shows an enlarged Axial section of the braking device; Figure 3 is a section along line 3-3 of Fig. 2, with certain parts omitted for the sake of greater clarity of the drawing shown in section; Fig. 4 shows a detail of the device from seen at the rear in the direction of arrow 4 of Fig. 2; Fig. 5 is a section through the device along the line 5-5 of Fig. 2, shown at the moment of triggering the braking; Fig. 6 shows the schematic partial view of an embodiment variant te of the device.

The elevator car (1) shown in Fig. 1 slides on a vertical one Mast (2) along the z. 13. Belongs to a scaffold and on one side with a Rack (3) is provided. The cabin (1) slides on the mast (2) with the help of a Drive motor (4) along, the output shaft of which carries a drive wheel (5) that continuously engages in the rack (3). On the same side of the cabin (1) a safety brake (6) is installed; this is equipped with a gear (7), which also continuously engages in the rack (3). The device (b) is used to brake the cabin (1) as soon as it reaches a predetermined level when traveling downwards Speed exceeds.

As shown in Fig. 2, the safety brake (6) consists of a u Housing (8), a shaft (9) with axis X-X, which rotates in the housing, a centrifugal device (10) and a brake (11).

When the car (1) slides down the mast (2), the shaft rotates (9) in the weighting of arrow f in Fig. 3.

The housing (8) consists of: a cylindrical central part (12), which is provided with end flanges; from a first end wall (13) which is removable and is tightly attached to the central part (12) and has a tubular, has outwardly facing projection (14); from a second end wall (15) which is also removable and has a central opening (16), as well as a removable one Cap (17) which is attached to the end wall (15) and over the opening (16) of this Wall has a window (18) covered with a transparent plate (19). The cap (17) is accessible for maintenance from inside the car of the elevator (1). The walls (13 and 15) create a first sealing chamber (8a) of the housing (8) limited where the brake (11) is housed; a second sealing chamber (8b) the housing, which is limited by the cap (17) and wall (15), allows observation the centrifugal device (10).

The light (9) crosses - with sealed transitions - the tubular one Projection (14) of the housing, with an anti-friction ring (20) interposed, which is prevented from reaching the station by a pin (21). The gear (7) is seated on the end of the shaft (9) protruding from the tubular projection (14). Inside the housing (8), the shaft (9) has a section provided with a groove (22) (9a), which continues in a section (9b) with a smaller diameter. A radial shoulder (23) borders the two sections (9a and 9b) against one another away. The end of the narrowed section (9b) is at the same height as the opening (eleven) of the housing (8).

The centrifugal device (10) contains in its cylindrical part a holding part (24), the diameter of which corresponds to that of section (9a) of the shaft (9) is equivalent to; this Ilalteil (24) has a blind notch (25) in the middle on, which adapts exactly to the narrowed section (9b) of the shaft (9). A radial one The end face (26) of part (24) lies on the radial shoulder (23) of shaft (9) nuf; the lialteteil (24) is completely guided through the opening (16) of the housing (8), namely with interposed bearings (27), for. ii. needle bearing that with suitable Sealing devices (not shown) is equipped. Between the shoulder (23) of the shaft (9) and opening (16) of the housing (8), the holding part (24) fits into one Gear (28). The free end of part (24) protrudes into the viewing chamber (8b) of the Housing (8) and has a notch (29). This, as a cross section Fig. 3 and 4 shown notch (29) has the shape of a triangle, its longest Side (29a) is curved and formed by the contour of part (24); the other two Triangle sides are straight, with the longer one, (29b), the bottom of the notch (29) and the shorter, (29c), delimits an almost radial rear side of this linkerage. "backside is to be understood in relation to the direction of rotation f. The sides (29 b and 29 c) form an angle that is somewhat more obtuse than right-angled - e.g. B. 1000 - is. Of the Holding part (24) has a transverse bore (30) which is cut into the bottom of the notch (29) opens and on the other side a section (30a) with a larger diameter forms. An axial bore (31) also runs through part (24), but without to encounter the bore (30). A head piece (32), the axial width of which is somewhat smaller is than that of the notch (29) (Fig. 2), the bottom of this is in the rest position Notch on. In cross-section (Fig. 3) this head piece has the shape of a right-angled Trapezoid, of which a right angle (32a) lies exactly on the angle that is formed by the straight sides of the notch (29), while the acute angle the notch protrudes beyond the periphery of the holding part (24).

In the rest position of the head piece (32) there is a triangular free one Space (33) with about 100 opening between the back of the head piece (32) and the back of notch (29). A passage (34) runs through the full height Head piece (32); if this is in the rest position, the passage is in the exact extension the bore (30) of part (24); a return shaft (35) leads with a certain amount of leeway through the narrow part of the bore (30) as durob the passage (34) is on the radial outer surface of the head piece (32) held by a hook (36) and protrudes into the wide section (30a) of the bore (30). A conical coil spring (37) is between which the two bore sections (30) delimit one another Shoulder (38) and a nut screwed onto the free end of the return shaft (35) (39) excited. It should be noted that the passage (34) does not go through the center of gravity (G) runs from the head piece (32).

As shown in Figures 2 and 5, there is a fixed stop (40) arranged in chamber (8b) of the housing, specifically in the radial plane of the head piece (32); it is attached to the outer surface of the housing end wall (15). The radial position this stop (40) is such that the head piece (32) - if it is the ground the notch (29) rests - very close to the stop (40) vorbeiläuit, oboe him meanwhile to touch. But is the speed of rotation of the holding part (24) sufficiently high, the centrifugal force puts the head piece (32) in a Rotational movement around its edge (32a) against the tension of the spring (37), due to the fact that the passage (34) does not pass through the center of gravity (G) of the head piece runs; this movement continues until the rear of this head piece practically touches the back of the notch (29). The head piece then protrudes sufficiently far radially with respect to the holding part (24> out, so that it is no longer at the stop (40) (Fig. 5) can slide past.

The brake (11) consists of a second disc - alternately fixed or rotating - which is axially displaceable between the gear wheel (28) of the holding part (24) and an annular spacer (41) is mounted around shaft (9) and against the inside of the end wall (13) of housing (8). Included in the set of discs three movable disks (42) wedged on section (9a) of shaft (9), and two non-rotating disks (43), the outer circumference of which on the inner itillen (44) of the central part (12) of the housing (8) are keyed. The one the spacer (41) closest movable disc (42) is with a certain margin between this spacer and an Xundklammer (45) mounted in a The groove of the shaft (9) is seated. This gives it limited axial freedom of movement.

The three movable discs (42) each have three openings (46), the angular distance of which is 1200 (Fig. 3); three screws (47) with play through the aligned openings of the three discs the side of the spacer (41) are the flat screw heads (48), which in the opening of a positioning ring (49) are welded the ring is mounted so that it can rotate freely around spacers (41). At the opposite screw ends, protruding from the washers is a gear drive (50) on each of the screws (47) screwed, which continuously acts on the gear (28) of the holding part (24).

Finally, elastic ones are normally in their position Elements (51) - e.g. B. Belleville Washers - Between Heads (48) each Screw (47) and the movable washer closest to the head (48). The discs have an axial play so that the annular heating linings (52), with which the movable discs are provided, when the shaft (9) rotates rub lightly against the fixed discs.

The toppings are z. II. Made of frit bronze or the fixed ones Steel washers.

The braking device (6) is also equipped with a breaker (53> equipped which is operated by a lever (54); the end of the lever carries one Holle (55). This role is held by the two legs of a fork (56), which forms the end of a lever (57), the opposite end of which by a hinge is detachably mounted on a fitting (58); this fitting sits on the stop (40). A screw (59) is screwed into a blind hole with an internal thread (60), which is let into the narrowed section (9b) of shaft (9); the screw is freely guided through the threadless passage (31), which is coaxial with the holding part (24) is running. The free screw end (59) forms a semi-flat surface (61), the a rectangular plate (62) rests on it. The plate is so on the end face of the holding part (24) so that it stops the rotation of screw (59) (Fig. 2 + 4). That free land of the screw (59) continuously acts on a certain point on the lever (57>, via a suitable return spring in the cow position located breaker lever (54).

The braking device described works as follows: Slides down the elevator car at normal speed, the wheel (7) and shaft rotate (9) in the direction of arrow f. The shaft (9) drives through its rotation - via its Grooves (22) - the three movable discs (42) and, by friction, the bottom part (24) with its head piece (32).

It should be noted that the holding part (24) is not only due to the friction between the wall of notch (25) and the narrowed section (9b) of shaft (9) is driven, but also by the drive wheels (50), with only the very low heating of the bearing (27) represents a moment of resistance. About security can still be increased, by the way, as a variant in the holding part (24) - between the gear (28) and bearing (27) - one or more adial bores are provided in which in each case a spring is inserted, which acts on a ball; the bullet penetrates partially into a notch in section (9b) of shaft (9), as in (63) shown in Fig. 2.

As long as the speed at which the car (1) slides down the mast (2), does not exceed a preset value, the head piece (32) lies on the ground the notch (29) by acting on the spring (37) or it is located in the equilibrium position so that it just slides past the stop (40) without touching him. Under these conditions, wave (9), the three, move movable discs (42), the Hing (49) and holding part (24) together, wherein the Drive wheels (50) do not move in relation to gear wheel (28). During this movement the linings (52) of the movable disks exert a continuous, light frictional pressure on the fixed panes and thus cause the coverings to self-clean and the relevant friction surfaces.

As soon as the prescribed speed is exceeded, stops the speed of rotation of the shaft (9) and the holding part (24) so that the Head piece (32) under the action of centrifugal force in relation to the holding part (24) rotates around its edge (32a) so noisily that it protrudes far enough in the radial direction and can no longer slide past the stop (40).

If the headpiece (32) comes in front of the stop (40), it hits against it and immediately stops the rotary movement of the holding part (24) firmly connected to it (Fig. 5). For the sake of clarity, the hadial directions z1, z2 and Z3, which denote the three screws (47), shown in Figs. 4 and 5. As the shaft (9) continues to rotate and so do the disks (2) and the three drive wheels (50) drives, the latter begin to rotate on the stationary gear (28), whereby these drive wheels are screwed onto the screws (47) and the one behind the other Slices are finally pressed together firmly. The gradual compression of the Washers (51) in the course of this screwing process causes a gradual Tighten the brake.

The thread pitch of the screws (47) and the characteristic values of the washers (51) are matched so that the shaft (9) and thus the cabin (1) after a certain Number of revolutions of the shaft (9) comes to a complete standstill. The choice of the Head piece (32) and the spring (37) as well as the position of the nut (39) on the return shaft (35) allow the desired sliding speed to be easily adjusted.

Meanwhile, the immovable in the holding part (24) and in the rotating * shaft (9) screwed in screw (59) gradually out of part (24) out and moves the middle part of lever (57) in front of you, which after a certain number of rotations of the shaft (9) an interruption of the power supply to the Driving the car (1) causes.

The one acting on the head piece (32) when the brake is tightened Braking torque is much weaker than the braking torque transmitted through the disks; it can e.g. B. be about 1/100 of the latter.

To return the safety brake (6) to the starting position, only needs the cap (17) of the housing (8) removed and - with any, suitable tool - the holding part (24) in the desired weighting around the necessary Number of revolutions to be rotated until the three drive wheels (50), whose axes are firmly connected to the shaft (9) and are therefore immobile, far enough have shifted on the screws (47) towards the screw ends; through this The pressure on the set of disks (42 and 43) is loosened again.

You can see that after activating the safety brake the shaft (9) remains immobile even when the head piece (32) (the now is no longer subject to centrifugal force, since the holding part (24) is stopped) releases from the stop (40) and returns to the itu position. This is a major asset of the facility.

Since the head piece (32) is located in a chamber (8b) of the housing, which is separated from the main chamber (8a) with the braking device, it can can also be continuously observed through the window (19) of the cap (17). In addition, it is due to the sealing of chamber (8a) with the brake discs (which the head piece (32) does not take up) possible, this chamber (8a) with oil to fill, approximately up to level A in Fig. 2, whereby the self-cleaning effect of the friction surfaces of washers (42 and 43) is reinforced. You will also find that you only need to change the number of disks of the brake (11) in order to achieve its performance to change.

Fig. 6 shows schematically how the same braking device also in Can be used in cases where the safety brake in both directions of travel of cabin (1) must be effective, d. H. in both directions of rotation of the shaft (9). In In this case there are two notches (29b and 29e) and two head pieces (32b and 32 ) intended. These head pieces are driven by a spring over one and the same return shaft (35b) retrieved; this shaft is equipped with a conical compression spring (37b) and is guided with play through a hole (30b) in the holding part (24), which the b two notches and two passages running through head pieces (32 and 32c) (34 and 34 ¢) connects to one another; the b passages are usually aligned the hole (mob). The two head pieces (32b and 322) and the corresponding Notches (29b and 29c) are the same, but in opposite directions of rotation aligned. In this way, one of the head pieces abuts in each direction of rotation the stop (40) as soon as the permitted speed is exceeded.

In addition, the disks (42) have a second set with one another aligned openings at 1200 angular intervals and offset from the first set of holes. These openings are only indicated by their xadial directions z, Z5 and Z6 in Fig. 6 indicated.

The additional holes allow screws of the same type as (47) out, the threads of which, however, run in opposite directions and each carry a drive wheel, which engages in the gear (28).

From this it is clear that - regardless of the direction of rotation of the shaft (9) - when the holding part (24) is blocked by one of the two head pieces, one of the two drive wheel sets causes the pulley set to be pressed together while the second set, consisting of three drive wheels, is shifted in the weighting, in which the brake is released. All the advantages of the facility remain here exist.

Of course, the braking device (6) can also be used for other means of transport can be used, for example in those with chain or friction drive, which have a preset Not allowed to exceed speed.

Claims (9)

Claims 1. - Safety brake for something sliding along a surface means of transport, in particular for elevator cars; it consists of a housing, which can be attached to the means of transport and in which a shaft rotates, on whose end protruding from the housing sits a drive wheel that does not slide engages on said surface; also made of panes firmly connected to the housing, which are alternately mounted with movable disks fixed on the shaft; from an axial pressure element that acts on the discs and has a thread, which engages in a thread firmly connected to the movable disks, as well as has a toothing and a toothed holding part which engages in this toothing and carrying a centrifugal element characterized in that it (32, 32b - 32c) by its actuation a fixed in relation to the housing (8) Stop (40) is applied. 2. - Safety brake according to claim 1, characterized in that the stop (40) attached to the housing (8) and the holding part (24) with frictional contact mounted on the shaft (9) and equipped with a gear (28), the Axial pressure element a screwed onto the end of a screw (47) with a head (48) The drive wheel (50) carries the screw with play through the movable washers (42) is performed and the drive wheel (50) engages in the gear (28). 3. - Safety brake according to claim 2, characterized in that said holding part (24) on the end opposite the drive wheel (7) the shaft (9) is mounted and via a bearing (27) through a wall (15) of the housing (8) is guided, on the outside of which a removable cap (17) with a window (19) is provided, which delimits a SicbLhnmmer (8b) in which the centrifugal element (32, 32b - 32C) is housed. 4. - Safety brake according to claim 3, characterized in that the bearing (27) is tight and the other collar of the shaft (9) is also sealed is guided through the housing (8). 5. - Safety brake according to one of claims 2 to Ii, characterized marked, then (read the axial pressure element several sets of drive wheel (50) / cap screw (7-48), which are evenly distributed on the disks and with all Drive wheels (50) engage in the gear of said llalteils (24). - Safety brake according to one of claims 2 to 5, characterized in that that the movable disc (43) has a second set of screw / drive wheel analogous to the first set (47 - 50) carries, but with an opposing thread, and a second centrifugal element (32C) is actuated so that itotation in opposite directions the shaft abuts against a stop (40) attached to the housing (8). 7. - Safety brake according to one of claims 1 to ó, characterized in that that the centrifugal element consists of a head piece (32, 32b - 32C>, which is movable radially in a notch (29, 29b-29C) of the holding part (24) and is brought back into this by a February (37, 37). 8. - Safety brake according to claim 7, characterized in that the center of gravity (G) of the head piece (32, 32b-32C) opposite the action section the spring (37, 37b> is offset and the notch (29, 29b - 29c) the head piece allowed limited rotational movement around one of its edges. 9. - Safety brake according to one of claims 3 to 8, characterized in that that a safety screw (59) is screwed into the end of the shaft (9) and is guided in the blobked state through said holding part (24), this Screw a breaker (53 - 57) for the drive mechanism of the vehicle (1) applied.