GB2053344A - Door or gate actuating means - Google Patents

Abstract

A door or gate actuating means with an electrical actuating motor unit drivingly connected to traction means for the movable door member, by way of a belt drive (17) which is guided by a middle or drive pulley (27) mounted on the drive shaft of the actuating motor unit and two outer pulleys (29, 30) which serve as belt guides and are mounted on fork limb portions of a plate (28). The plate (28) is pivotal about an axis (31) extending parallel to the motor drive shaft and is spring loaded into a normal operating position by a cantilever arm (32) engaged by operating elements (35, 36) of a pair of switches (37, 38). The operating elements (35, 36) of the switches (37, 38) are arranged to be in contiguous relationship with the cantilever arm (32) in the normal operating position of the plate (28) and are held in these positions by adjustable bias means comprising springs (39, 40) and pivotable cams (41, 42). <IMAGE>

Description

SPECIFICATION Door or gate actuating means This invention relates to a door or gate actuating means, particularly for garage doors.

More particularly, the invention is concerned with door or gate actuating means for use with an electrical actuating motor unit which is drivingly connected to a traction means for the movable door member, by way of a belt drive or like movable actuating member. The belt (or the like) is guided so as to engage three belt pulleys, namely a middle pulley which is formed or arranged on the drive shaft of the actuating motor unit as a belt drive pulley and the two other pulleys which serve as belt guide pulleys. The belt guide pulleys are mounted on fork limb portions, which extend on both sides of the belt drive pulley, of a plate which is pivotal about an axis extending parallel to the motor drive shaft, in such a way that the belt extends around the belt drive pulley with a deflecting contact pressure and angle of looping around the pulley.The plate, which is spring loaded into the normal operating position, has a cantilever arm which is arranged to engage into the path of operation of operating elements of a switch means, which operating elements are disposed on both sides of the cantilever arm in the course of the pivotal movement of the plate.

A door or gate actuating means of this kind, which is in the form of a chain-type traction actuating means is disclosed for example, in German utility model No. 78 17 731 which already operates in an advantageous manner, from many points of view, and is simple to mount, while already providing protection from accidents, which is required with such an actuating means, by switching off or reversing the direction of rotation of the actuating motor, in the event of a resistance being presented to the movement of the door member, in particular due to an outside action.

In this arrangement, the drive belt which extends from the motor unit for transmitting the actuating movement to the traction means for moving the door member was passed by means of two belt guide pulleys around the belt drive pulley which is provided or disposed at the output of the actuating motor unit, in such a way as to provide a sufficiently large angle of belt looping around the pulley to ensure that the drive force is transmitted from the belt drive pulley to the belt. The question of setting a given suitable belt tension is not discussed in the above-mentioned specification.

By mounting at least the belt guide pulleys on a plate which is then mounted pivotally about an axis disposed outside of the drive shaft, it is possible at the same time to ensure that the run of the belt which is more heavily loaded, depending on the direction of actuating movement, applies a higher contact force to the belt guide pulley associated therewith, than the force applied by the other run of the belt to its respectively associated belt guide pulley. If, as a result of an obstacle in the path of movement of the movable door or gate member, a particularly high load occurs in one run of the belt, because the actuating motor initially continues to drive it, the plate is pivoted, according to the belt run which is subjected to the heavier loading, so that the plate actuates one of two switches, by way of a cantilever arm.The actuated switch causes the motor to be cut out or switched over in such a way that its direction of rotation is reversed and thus the door member is released again from the obstacle. The other switch which is arranged in the other direction of pivotal movement also permits the actuating motor to be switched off or switched over, in the opposite direction of door or gate movement or the opposite direction of actuating movement of the actuating motor. As the base loads for the door movement in the open position and in the closed position may be of different magnitudes, that possibility is taken into account by the switch actuating action being so arranged as to be suitably adjustable.

If therefore, as observed in the abovementioned utility model, the plate is spring-loaded towards its middle position, in the normal load condition, depending on the belt run which is subjected to a loading, the plate deflects in one or other direction of pivotal movement, by a greater or lesser angle of pivoting, without the respective switch being actuated in such movement. It is only when the plate pivots through a distance which exceeds a given angle of pivotal movement that the cantilever arm engages one switch or the other, by means of its two adjustable abutments.

Therefore, the switching means, for giving protection from accidents, is primarily dependent on pivotal movement. This involves disadvantages because a certain amount of pivotal movement is allowed for the normal load range, so that the plate can perform a "see-saw motion" which will occur when there are low levels of resistance to movement in the normal load range; if there is suitable resonance, this also simulates the conditions obtaining in the accident-prevention operating mode, even without an obstacle to movement of the door or gate. The fluctuations in load which are applied to the door member by greater or lesser wind pressure also fail to be considered in this respect.

The present invention seeks to provide a door or gate actuating means of the above-indicated kind, which operates in a clearly separate manner in regard to its mode of operation under normal operating circumstances and under accidentprevention operating circumstances, and which in addition, generally permits better adjustment of the actuating threshold values, in dependence on belt tension.

According to the invention, a door or gate actuating means for use with an electrical actuating motor unit which is drivingly connected to a traction means for the movable door member, by way of a belt drive or like movable actuating member, wherein the belt or the like is guided so as to engage three belt pulleys, namely, a middle pulley which is rotatable by the drive shaft of the actuating motor unit as a belt drive pulley and two outer pulleys which serve as belt guide pulleys and are mounted on fork limb portions, which extend on opposite sides of the belt drive pulley, of a plate which is pivotal about an axis extending parallel to the axis of the middle pulley, in such a way that the belt extends around the belt drive pulley with a deflecting contact pressure and angle of looping around the pulley, the plate which is spring loaded into the normal operating position having a cantilever arm which is arranged to engage into the path of operation of operating elements of a switch means, which operating elements are disposed on opposite sides of the cantilever arm in the course of the pivotal movement of the plate, characterised in that the operating elements of the switch means are arranged in such a way as to lie virtually without any spacing against the cantilever arm in the normal operating position of the plate and are held in said position by adjustable bias means.

In the present invention, the circumstances of switching off or switching over the motor when an obstacle occurs, for the purposes of accident prevention, are brought about by a rating or parameter-determining action which is dependent on force, as opposed to dependent on travel movement. The operating elements of the switches or cover means or the like associated therewith, which can be supported in a stationary fashion, lie more or less directly, as viewed from both sides, against the cantilever arm of the pivotally mounted plate. In this arrangement, the spring forces which act on both sides are already preselected to be of such a value, in the rest condition, that, in normal operation, the plate does not perform a pivotal movement which causes operation of one of the switches.It is only in the event of the necessity to provide protection from accident, that is to say, when there is a correspondingly high resistance, the value of which is above the interference level which obtains in the normal operating mode, that the actuating motor is switched off or switched over.

This arrangement therefore permits precise adjustment, by varying the bias force of the springs; in normal operation, the plate is virtually free from pivotal movement so that in normal operation there is no see-saw or hunting motion, when the movement of the door or gate meets with correspondingly low interference or hindrance which occurs periodically. This means that the actuating means according to the invention is less susceptible to interference in operation and at the same time can be more sensitively adjusted with regard to the threshold value which represents the level of resistance that marks initiation of the accident-prevention mode.

Preferred features of the invention are set forth in the subsidiary claims.

An embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawing.

The drawing shows that part of the door or gate actuating means to which the measures and preferred design features according to the invention relate. In other respects, other design features can be assumed as being fundamentally the same as those set forth in the embodiment of German utility model No. 78 17 731, to which reference is here made in that respect. In principle, it is possible for a door or gate actuating means having the features which here determine the spatial configuration, to be designed in such a way that the drive belt, for example in the form of a chain, provides directly for the movement of the door or gate and therefore has for example, a traction or pulling member.

As in the case of the above-mentioned known arrangement, the embodiment illustrated herein also has a pair of belt guide pulleys 29 and 30, in order to increase the angle of looping of the drive belt 17 around the middle or drive pulley 27. The pair of belt drive pulleys 29 and 30 form the two free ends of the limb portions of a kind of triangular configuration, the apex of which is formed by the belt drive pulley 27 which is coaxially fixed on the drive shaft of the actuating motor unit. (Not shown.) The belt 1 7 can lead to another belt pulley as is the case in the known arrangement.

Again, in a similar manner to the arrangement of the above-mentioned German utility model, the belt guide pulleys 29 and 30 are mounted on a plate 28 which in turn is mounted for pivotal movement about an axis 31 which extends parallel to the axis of the pulley 27. In this arrangement, the two belt guide pulleys are disposed on limb portions which are so arranged as to extend on opposite sides of the drive shaft.

Viewed generally, the plate 28 is formed by the root portion which is pivotal about the axis 31, the two lateral fork limb portions bearing the pulleys 29 and 30, and a cantilever arm 32 which extends in alignment with the axis 31, and in the position illustrated in alignment with the axis of the pulley 27. The plate 28 is braced laterally thereof. For this purpose, the end portions of the fork limb portions, which carry the belt guide pulleys 29 and 30, are connected together so that viewed generally, the resulting construction is in the form of a plate with an opening in which the drive pulley 27 is disposed and remains freely movable, even when the plate 28 is in the position of maximum pivoting motion.

As the drawing shows, operating elements 35 and 36 of switches 37 and 38 engage virtually without play on the side surfaces of the arm 32, i.e. they are in contiguous relationship therewith.

The arrangement is such that one switch is operated when the plate 28 pivots in one direction and the other switch is operated when the plate pivots in the opposite direction. Depending on the choice of design, the operating elements 35 and 36 may provide for direct or only indirect actuation of the switches. The operating elements are held stationary in such a way that they each remain in the rest position illustrated, under the bias force of associated coil springs 39 and 40.

Therefore an operating element may only move towards the associated switch and cannot, for example, follow pivotal movement of the cantilever arm whereby it moves from the illustrated position towards the other switch.

The operating elements 35, 36 are provided with adjustable bias means as follows.

Associated with operating elements 36 and 35 and thus with switches 37 and 38, are coil springs 40 and 39. The springs 40 and 39 press against the elements 36 and 35. The rearward ends of the springs, that is to say, the ends which are remote from the arm 32, bear against adjusting means in the form of cams 42 and 41 which are mounted for rotary movement about screw shank portions, in the direction indicated by the arrows in the drawing. The peripheral surfaces of the cams are of a spiral configuration with respect to the respective screw shank portion, and thus the axis of rotational movement of the respective cam.

Accordingly, with the cams 41,42 in different rotary positions, a correspondingly different distance can be set between the axis of rotary movement and the rearward end of the associated spring. This provides a very precise and easily operable, continuously variable adjustability in respect of the biasing force of the spring. This arrangement therefore permits the belt loading to be adjusted to a desired value which is strictly adapted to the respective conditions obtaining, under which belt loading the plate and thus the arm 32 can be pivoted, entraining the operating element 35 or 36 respectively against the preset force of the respective spring 39 or 40.

The two switches, the associated springs and the adjusting cams are of an identical configuration, which is advantageous from the point of view of production processes. The various components are pre-assembled on mounting plates 43 and 44 respectively. The adjusting cams 41 and 42, which however are individually operable with regard to the adjustment operation, make it possible to take account of different impediments in the movement of the door or gate when being opened on the one hand and when being closed on the other hand. It would even be possible to set different threshold values for obstacles which trigger the accident-prevention switch-off effect, in regard to the two directions of door or gate movement.This thus provides that, besides the possibility of precise adjustment, in consideration of the switch arrangement which engages the cantilever arm with little or no clearance, for normal operation, the design of the door or gate actuating means in accordance with the invention is such that impediments to operation of the arrangement, which occur during movements of the door or gate, do not usually result in the plate 28 suffering from a corresponding swinging movement which can cause the system in normal operation to become unstable so as improperly to simulate the situation which arises when movement of the door or gate is impeded by an obstacle, resulting in the actuating means being switched off to prevent an accident.

As the belt tension is a further influencing parameter, in regard to setting up or tuning the whole system, the belt tension is arranged to be adjustable. This is easily achieved by the axis member 31 about which the plate 28 is pivotally mounted being secured in turn to a carrier plate 45. The carrier plate 45 can be disposed in different positions relative to the drive shaft of the pulley 27 and is adjustable by means of screw-slot connections 46 and 47. Thus the distance between the drive shaft of pulley 27 and the spindles of the belt guide pulleys 29 and 30 may be adjusted to different values.In order to keep both runs of the belt 1 7 in equal alignment as far as possible, the slots 46, 47 extend parallel to the angle bisector of the triangle which is formed between the drive shaft of pulley 27 as the apex of the triangle, and the two pulleys 29 and 30 as the free ends of the sides of the triangle. By virtue of the arm 32 also extending in that direction, when the plate is precisely disposed in the slots, there are no deviations in regard to the contact of the arm 32 with the switch operating elements 35 and 36. In order to ensure that the plate 45 is disposed in a straight line in the above-indicated manner, the plate is also provided with a further slot 48 which extends in alignment with the above-mentioned angle bisector and through which extends a guide bolt. By virtue of this threepoint mounting, the carrier plate 45 with the plate 28 mounted thereon, can only be displaced precisely in the direction of the slots and can be secured in the different positions of displacement, depending on the respective tension to be set in the belt 17 or depending on uniform distances between the drive shaft of pulley 27 on the one hand and the respective belt guide pulleys 29 and 30 on the other hand.

Claims (9)

1. A door or gate actuating means for use with an electrical actuating motor unit which is drivingly connected to a traction means for the movable door member, by way of a belt drive or like movable actuating member, wherein the belt or the like is guided so as to engage three belt pulleys, namely a middle pulley which is rotatable by the drive shaft of the actuating motor unit rs a belt drive pulley and two outer pulleys which serve as belt guide pulleys and are mounted on fork limb portions, which extend on opposite sides of the belt drive pulley, of a plate which is pivotal about an axis extending parallel to the axis of the middle pulley, in such a way that the belt extends around the belt drive pulley with a deflecting contact pressure and angle of looping around the pulley, the plate which is spring loaded into the normal operating position having a cantilever arm which is arranged to engage into the path of operation of operating elements of a switch means, which operating elements are disposed on opposite sides of the cantilever arm in the course of the pivotal movement of the plate, characterised in that the operating elements of the switch means are arranged in such a way as to lie virtually without any spacing against the cantilever arm in the normal operating position of the plate and are held in said position by adjustable bias means.

2. A door or gate actuating means according to Claim 1, characterised in that the bias adjusting means comprise coil springs extending parallel to the direction of operation of the operating elements, the ends of the springs remote from the contact surface with which the respective operating element lies against the cantilever arm respectively lying against the periphery of a movable cam, the cam- periphery being of a spiral configuration disposed around an axis of rotation, around which axis the cam can be disposed in different positions of rotation.

3. A door or gate actuating means according to Claim 1 or 2, characterised in that each switch of the switch means, as well as the adjustable bias means, is mounted on a plate, the plate being of identical configuration in both directions of pivotal movement of the cantilever arm.

4. A door or gate actuating means according to any one of Claims 1,2 or 3, characterised in that the pivot axis of the first-mentioned plate is secured to a carrier plate which can be disposed in different positions relative to the axis of the middle pulley, so as to vary the distances between the belt drive pulley on the one hand and the belt guide pulleys on the other hand.

5. A door or gate actuating means according to Claim 4, characterised in that screw-and-slot means are provided for securing the carrier plate in said different positions.

6. A door or gate actuating means according to Claim 5, characterised in that the screw-and-slot means extend parallel to the angle bisector of a triangle formed by the belt drive pulley as the apex and the belt guide pulleys as the free ends of the limb portions.

7. The combination of a door or gate actuating means as claimed in any one of Claims 1 to 6, and an electrical motor unit coupled to the middle pulley so as to drive the same.

8. A door or gate actuating means substantially as hereinbefore described with reference to the accompanying drawing.

9. The combination of Claim 7, substantially as hereinbefore described with reference to the accompanying drawing.