Emergency release device

An emergency release device for an elevator for persons that includes manually operable drive elements, by which the elevator cage can be moved by way of the elevator drive. The device further includes operating elements by which an operative connection with the elevator drive can be produced and the brake at the elevator drive released. A crank device, a flexible shaft and a switchable crown wheel gear transmission are present as drive elements. The switching or coupling in of the crown wheel gear transmission takes place via a handle with a toggle joint mechanism, a cable pull and an engaging fork. A handle for a remotely actuable brake release by way of a cable pull is present at the crank device.

SUMMARY OF THE INVENTION
 1. Field of the Invention
 The present invention relates to a manually actuable emergency release
 device for an elevator in or at a building, with a cage which is guided by
 means of movable carrier elements by way of a drive pulley. The drive
 pulley is driven by means of a drive with an elevator motor and a brake
 and with or without a gear transmission. The emergency release device
 consists of a device for producing the operative connection with the
 elevator drive, a manually operable drive element, mechanical transmission
 means and operating elements for the remote actuation of the operative
 connection with the elevator drive.
 2. Discussion of the Prior Art
 Various methods and devices are known for an emergency release of
 passengers from a cage, which is blocked between two storeys, of an
 elevator. The present invention is proposed for elevator installations
 which do not have automatic evacuating travel equipment. In such cases the
 evacuation or the emergency freeing of the confined passengers is carried
 out by manual release of the brake and turning of a handwheel or of the
 driven plate at the elevator motor. Such a manual emergency release,
 however, presupposes good access to the devices to be operated.
 In the case of elevators without an engine room or with an engine room with
 poor accessibility the direct access to the mentioned devices is not
 guaranteed. Other methods and devices have to be provided for such cases.
 European reference EP 0 244 030 discloses manually actuable release and
 drive equipment for stairlifts and similar transport equipment for
 persons. In the case of this equipment a handwheel with coupling sleeve
 can be pushed on a shaft displaceable in longitudinal direction, wherein
 two bevel pinions are brought into engagement against spring force and an
 electrical contact is actuated. The brake at the drive motor of the
 conveying equipment is released at the same time by the thrust movement of
 the handwheel shaft.
 For use of this device a more or less direct access to the drive of the
 conveying equipment is required. In order to be able to center the
 coupling equipment without problems, the handwheel shaft must not be very
 long. On pushing in of the handwheel shaft, the spring force of the
 displacement shaft with the primary bevel pinion and the release force of
 the brake release lever of a brake must be overcome. After the completed
 engagement, the brake release lever catches in a groove of the handwheel
 shaft and has to keep this in the engaged setting, otherwise the tooth
 forces in operation have a constantly uncoupling effect.
 As the brake in this setting remains permanently released, a self-locking
 gear transmission is inevitably necessary. Otherwise a dangerous state
 contrary to specification would arise, because the load carrier or the
 elevator cage would automatically set into motion, even with small
 out-of-balance weights between the load carrier and the counterweight, as
 soon as the brake is released. The prior known equipment accordingly
 cannot be used for drives with high efficiency and it is also suitable
 only for small drives with low drive power, low efficiency and good
 accessibility.
 SUMMARY OF THE INVENTION
 The present invention now has the object of creating an improved manually
 actuable emergency release device which functions reliably in operation
 and is easy to actuate and economical to produce.
 The emergency release device according to the invention is distinguished by
 the fact that for the manual movement of the elevator cage by way of the
 elevator drive a simple, mechanical crank device with a preferably
 flexible shaft as well as a gear transmission, which can be switched in,
 are present for the operative connection with the elevator drive. As the
 switchable gearwheel of this gear transmission is displaceable along its
 axis, thus along the tooth flanks, without change in the depth of
 engagement, the gearwheel remains safely in engagement during the release
 operation.
 A flexible shaft or a crank rod can be used as mechanical, flexible
 transmission means for the movement of the elevator cage.
 The mounting of a speed reduction gear is advantageous, for example a crown
 wheel gear transmission, whereby the torque to be applied to the crank
 device and thus the loading of the connecting elements, for example a
 flexible shaft, are reduced.
 The use of a crown wheel gear transmission as a switchable operative
 connection has the advantage that the axis of the engageable and
 disengageable gearwheel does not necessarily need to lie parallel to the
 axis of the elevator motor, which would in fact require an unfavourable
 arrangement of the transmission means. Moreover, a torque transmission,
 which is free of reaction in the axial direction and the engaging, and
 disengaging of the operative connection with unchanging depth of
 engagement are thus possible.
 The crank device as well as the operating elements are preferably arranged,
 as a combination, in an actuation niche, wherein the actuation niche can
 be provided not only anywhere in the shaft wall, but also on the door
 front on a storey. In the case of an arrangement in the door front, a
 partial prefabrication at the factory is possible. The operating elements
 are distinguished by simple construction.
 Operating elements adapted to the purpose are constructed in the form of a
 first, self-restoring handle at the crank device and a handle remaining in
 drawn setting. The first handle at the crank device can be constructed as
 a bicycle brake lever and the second handle has a toggle joint mechanism,
 in order to retain the drawn setting.
 The brake at the elevator drive is released, without auxiliary current
 source, by way of a cable pull by the first handle on actuation thereof
 and can be blocked again at any time if the elevator cage, in the case of
 a large weight imbalance, should move too quickly.
 The operative connection with the elevator motor of the elevator drive is
 produced by way of a second cable pull by the second handle, wherein a
 cylindrical toothed pinion is then axially displaced until it is in
 engagement in a crown gearwheel. On actuation of this second detenting
 handle, the operative connection with the lift drive remains in place and
 does not have to be kept by permanent expenditure of force.
 After the produced mechanical coupling between the toothed pinion and the
 crown wheel, the manipulation of the emergency release device is confined
 to the application of torque by one hand to the crank and the drawing of
 the brake release handle by the other hand.
 By the crank device manually set into rotation the cage to be evacuated can
 be set into motion by way of the toothed pinion engaging in the crown on
 the drive motor shaft, the gear transmission, the drive pulley and the
 carrier elements.
 At least one checking control directly at the emergency release device and
 further sequential contacts at the elevator drive and in the elevator
 control secure a risk-free operation of the emergency release device,
 especially even in the case of unexpected switching back on of the mains
 voltage during a release manipulation.
 By freeing of the brake release handle and tipping over the toggle lever
 into the initial setting, the elevator is set in readiness for normal
 operation again after an emergency release, assuming that in the meantime
 the cause of the breakdown has been removed.
 In the case of activated emergency release device a constrainedly actuated
 safety contact prevents the normal switching-on of the elevator drive.
 In the construction with a crank rod, this is variable in length by means
 of telescopic construction of a part.
 The various features of novelty which characterize the invention are
 pointed out with particularity in the claims annexed to and forming a part
 of the disclosure. For a better understanding of the invention, its
 operating advantages, and specific objects attained by its use, reference
 should be had to the drawing and descriptive matter in which there are
 illustrated and described preferred embodiments of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
 An elevator drive with the emergency release device according to the
 invention is illustrated in FIG. 1. The elevator drive is arranged in the
 elevator shaft so as not to be directly accessible and consists of an
 elevator motor 23, a brake 25 with a brake release magnet 21, a gear
 transmission 26 and a drive pulley 27. Looped over the pulley 27 are
 carrier elements 28, which lead to an elevator cable, which is not
 illustrated, and to a counterweight, which is also not illustrated. A
 crown wheel 2 is fastened at its free front face to the elevator motor 23
 on the elevator motor shaft end. This crown wheel 2 belongs to the
 subassembly, which stands in direct operative connection with the elevator
 drive, of the emergency release device, which is laterally fastened to the
 elevator motor 23 of the elevator drive by way of a mounting part 22
 serving as an adapter. The active elements of this subassembly are
 accommodated in a housing 8. A shaft 4 is led through the housing 8 and is
 held at the housing outlet on the right in a bearing 5 and ends at the
 housing outlet on the left in a shaft coupling 9. A cylindrical toothed
 pinion 3 is seated, as a gearwheel, on the right hand shaft end. Fastened
 on the otherwise free shaft end of the elevator motor 23 is a crown
 gearwheel, called the crown wheel 2 in the following, and forms, together
 with the toothed pinion 3, a crown wheel gear transmission 1 when the
 toothed pinion 3 stands in engagement with the crown wheel 2. For this
 purpose the shaft 4, for the production of the operative connection with
 the elevator drive, is mounted in the housing 8 to be longitudinally
 displaceable along its axis together with the toothed pinion 3 and is held
 by a spring 7, during normal operation of the elevator, in the uncoupled
 setting, as illustrated in FIG. 1. Present in the housing 8, which is
 shown partially cut away, is an engaging fork 11 which is pivotably
 mounted at the lower end and bears by a forked end against a pressure ring
 6 which is present, directly to the right near the spring 7, to be
 longitudinally displaceable. The longitudinal displacing of the shaft 4 is
 effected by a pull wire 12 of a Bowden pull 13. The pull wire 12 is
 operatively connected with the engaging fork 11 so that an actuation of
 the engaging fork 11 draws the shaft 4 and together therewith the toothed
 pinion 3 to the left into engagement with the crown wheel 2 by way of the
 pressure ring 6 against the force of the spring 7. In this state the crown
 wheel gear transmission 1 is functionally ready. In the shaft coupling 9,
 the rigid shaft 4 is connected with a flexible shaft 15 in rotationally
 fast manner, wherein a switching sleeve 10 displacing with the shaft 4
 constrainedly actuates a safety switch 30 during the coupling process.
 The actuating parts of the emergency release device are accommodated in an
 externally accessible actuation niche 24. The actuation niche 24 can in
 principle be disposed anywhere in the building in the proximity of the
 elevator. The actuation niche 24 is advantageously closed by a flap, a
 door or a slide and is accessible for informed persons. The distance to
 the elevator drive is limited only by the length, which it is practicable
 to execute, of the flexible mechanical transmission means. In the present
 case of use, distances of, for example, two to three metres are concerned.
 A handle 14 and a hand crank 16 are disposed in the actuation niche 24. The
 tipping over of the handle 14 effects, by way the cable pull 13 with a
 cable wire 12, the uncoupling of the crown wheel gear transmission 1.
 Thanks to the toggle joint mechanism of the handle 14 this remains in the
 drawn setting. A handle 18 in the form, by way of example, of a bicycle
 brake lever is present at the hand crank 16 on a handle sleeve 17. On
 drawing of the handle 18 the actuation takes place, by way of a cable pull
 19 with a pull wire 29, of a brake lever 20 at the brake magnet 21 and
 thus a release of the brake 25 of the elevator drive. Through the rotation
 of the handcrank 16 the elevator motor can by way of the crown wheel gear
 transmission 1, and thus the elevator cage by way of the gear transmission
 26, the drive pulley 27 and the carrier elements 28, be moved in the
 desired direction. The movement is in that direction for which the smaller
 torque is needed. A simple mechanical storey indicator device, which is
 not illustrated, informs the person at the crank handle 16 about the cage
 position. This can be executed in the form of, for example, markings at
 the carrier elements, which presupposes a visual connection therewith.
 FIG. 2 shows the crown wheel gear transmission in plan view with the
 toothed crown of the crown wheel 2 and the cylindrical toothed pinion 3.
 The teeth of the crown wheel 2 and the teeth of the toothed pinion 3 have
 a shape favorable for mutual engagement. The teeth of the crown wheel 2
 are for this purpose formed to taper somewhat to a point in the direction
 towards the center and those of the toothed pinion 3 in the opposite
 direction. The probability of a mechanical jamming by hitting together of
 tooth cross-section surfaces during engagement of the toothed pinion 3 in
 the tooth crown of the crown wheel 2 is thereby extremely small.
 If the placement of the actuation niche 24 in the shaft wall is planned, an
 opening with closable access door must be provided at an appropriate
 location. Preferably, however, the actuation niche 24 is accommodated in
 the door front near a shaft door. In this mode of placement, a door front
 with a box arranged at the rear side and a closure door at the front side
 can be provided and prefabricated already at the factory.
 In the case of use of an articulated crank rod 31, this can be constructed
 to be telescopically extensible for a more convenient manipulation.
 Equally, the end member with the crank of a flexible shaft can, for the
 same purpose, preferably be withdrawn a bit out of the actuation niche 24.
 Instead of a crown wheel gear transmission 1 there can be used, with
 appropriate adaptations, also a spur wheel gear transmission or an
 internally toothed gear transmission. In these embodiments the shaft with
 the toothed pinion extends parallel to the shaft of the elevator motor and
 similarly engages by longitudinal displacement. These forms of
 construction are suitable for elevators in which space is available in the
 axial direction of the motor, for example in the case of flat motors or
 motors lying flat.
 The invention is not limited by the embodiments described above which are
 presented as examples only but can be modified in various ways within the
 scope of protection defined by the appended patent claims.