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(11) | EP 0 976 910 A2 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Device for the automatic control of the stop cursors of motor reducers in roller shutters |
| (57) This invention relates to a device for the automatic control of the stop cursors
of motor reducers used to handle winding window shutters, such as roller shutters,
or blinds. The device features two pistons (12) to engage or disengage the pinions (6) of the threaded rods (7) used to screw the stop cursors (9) with respect to the gear that drags them into rotation. |
[0001] This patent application relates to a device for the automatic control of the stop cursors of motor reducers used to handle winding window shutters, such as roller shutters, or blinds.
[0002] Electrical motor reducers have been used for a long time to automatize the handling of roller shutters through rotation in both directions to pull them up or down.
[0003] The maximum travel of the automated roller shutters is controlled and determined by limit switches activated by cursors in order to interrupt the power supply of the motor reducer as soon as one cursor interferes with its limit switch.
[0004] One switch is designed to stop the motor reducer when the roller shutter has completed its up travel, while the other switch intervenes when the roller shutter has completed its down travel.
[0005] The two cursors are usually screwed onto threaded rods - one right-hand and one left-hand - that are dragged into rotation in the same direction by the motor reducer used to handle the roller shutter.
[0006] More exactly, the two threaded rods are placed side by side and provided at their ends with pinions that are both engaged on the same crown gear housed inside a dragging ring activated by the motor reducer. The rotation of the said dragging ring makes the two cursors travel simultaneously and identically along their screwing rods.
[0007] When installing the roller shutter or blind, the installer must of course adjust the two cursors according to the maximum travel desired.
[0008] In absence of special automatic control devices, the initial adjusting operation is carried out through several attempts, by manually moving the cursors along their rods and making the roller shutter go up and down to test it.
[0009] It is obvious that this operation based on progressive approximation requires quite a long time.
[0010] Various devices have been developed so far to reduce the time needed to adjust the cursors during the installation of the roller shutters by automatically controlling the stop of the above-mentioned cursors.
[0011] In these automatic control devices, the threaded rods are able to make a short travel in longitudinal direction in order to determine the disengagement of the pinion of the crown gear of the dragging ring. In other words, in these automatic devices each threaded rod can be selectively disengaged from the dragging ring.
[0012] More exactly, each threaded rod is subjected to the axial thrust of a pre-compressed spring that maintains it in its working position which corresponds to the engagement between the teeth of the pinion and the teeth of the crown gear housed in the dragging ring. These devices are provided with a cam that - when rotating - allows for creating an axial thrust in the opposed direction to the above-mentioned retuming spring, with the backing of the rod and disengagement of the pinion from the dragging ring.
[0013] During the installation of the roller shutters, these automatic control devices must be used as indicated below. It must be said that these devices are supplied by their manufacturers with the two cursors in the end position and the two threaded rods connected with the dragging ring by means of their pinions.
[0014] First of all, the installer must disengage both threaded rods from the dragging ring through the above-mentioned cams and then activate the motor reducer until the roller shutter is completely lowered.
[0015] During the first down travel of the roller shutter, the cursors do not move since the rods are not dragged into rotation because the connection between their pinions and the dragging ring - that rotates together with the motor reducer - has been momentarily interrupted.
[0016] Now the installer must intervene on one cam to connect one of the threaded rods (the one on which the cursor that determines the end of the down travel slides) with the dragging ring. Then he must start the motor reducer and let it run until the roller shutter has completed the up travel.
[0017] During this second travel of the roller Shutter only one rod is dragged into rotation and the cursor travels away from its switch in a proportional way with respect to the up travel of the roller shutter.
[0018] Now the installer must intervene on the other cam to connect the second rod (the one on which the cursor that determines the end of the up travel slides).
[0019] During the next travel of the roller shutter, both cursors move in opposed direction along their rods and one cursor (the one that determines the down stop) interferes with its limit switch as soon as the roller shutter has completed the second down travel.
[0020] The automatic control has been accomplished with only three travels - two down and one up - of the roller shutter.
[0021] The purpose of the present invention is to improve these automatic control devices by eliminating the cams for the axial adjustment of the two threaded rods and replacing them with two pistons that can be manually grabbed, pushed or pulled.
[0022] This eliminates the need of using the screwdriver or spanner that are now necessary to tum the two cams. This means that the initial adjusting operation can be carried out without tools since, as already mentioned, the two pistons can be manually pulled or pushed.
[0023] The presence of the two pistons eliminates another inconvenience that can occur with the two cams. If lacking the necessary experience, the installer may use the cams to drag into rotation the threaded rod to carry out the adjustment by progressive approximation.
[0024] In this case the installer repeatedly tums the cam just like a screw with the risk of deteriorating it since the cam is designed to tum a very few times - the times necessary for the adjusting operation - as indicated above.
[0025] According to the present invention, each piston slides in a housing channel and guide with orthogonal axis with respect to the longitudinal axis of the threaded rod with which the piston works.
[0026] Each piston features a stem that ends on one side with a biting head and on the other side with a parallelepiped body featuring a front niche with two grooves of different depth connected by an intermediate inclined plane.
[0027] When the pinions of the threaded rods engage with the crown gear of the dragging ring, the tip of the rods is placed in the deeper groove of the two niches. In this way the pistons are completely extracted from their housing and guide. By manually pushing the two pistons inside their housing and guide the two rods are forced to back up and their tips - by interfering and sliding on the inclines planes - are progressively pushed out of the deeper groove until they stop against the shallower groove.
[0028] Vice versa, by extracting the pistons inside their housing, the two threaded rods are automatically pushed forward and their tips spontaneously tend to return in their position in the deeper groove because of the axial thrust of their returning springs.
[0029] For clearer explication purposes, the description of the invention continues with reference to the enclosed drawings whereby:
- Fig. 1 is an exploded view of the various components of the automatic control device;
- Fig. 2 is a cross-section of the automatic control device with a longitudinal plane over the axis of one of the two above-mentioned pistons, completely inserted in its housing and guide that corresponds to the disengagement of the pinions from the threaded rods of the crown gear of the dragging ring;
- Fig. 3 is a cross-section of the automatic control device with a longitudinal plane over the longitudinal axis of the two threaded rods used to screw the two cursors; in this figure one piston is inside its housing and the other piston is out of it;
- Fig. 4 is a view of Fig. 2 from left to right;
- Fig. 5 is an axonometric view of one piston.
[0030] With reference to the above mentioned figures, the automatic control device according to the present invention features a traditional structure comprising a cylindrical support casing contained inside a sleeve (1) made up of four rods (2) whose ends are fixed between one flange (3) and a hollow cylindrical drum (4) inside which the dragging ring (5) intemally provided with a crown gear (5a) is inserted and rotates.
[0031] The drum (4) houses a peripheral pair of pinions (6) splined on threaded rods (7) - one right-hand and one left-hand - that are subject to the axial thrust of their springs (8) and on which the corresponding cursors (9) are screwed that work together with the limit switches (10) fixed above their support bases (10a) anchored over the above-mentioned rods (2).
[0032] It must be said that the engagement between the pinions (6) located inside the drum (4) and the dragging ring (5) located outside the drum (4) is made possible by the presence of an opposed pair of grooves (4a) on the external circular wall of the drum (4).
[0033] The automatic control device according to the present invention also includes a box (11) with lid (11a) that is fixed and screwed onto the drum (4) and intemally features housings and guides for a pair of pistons (12), with each piston that slides along an orthogonal direction intersecting the longitudinal axis of one of the threaded rods (7).
1. Device for the automatic control of the stop cursors of motor reducers in roller shutters
of the type comprising a cylindrical support casing contained inside a sleeve (1)
made up of four rods (2) whose ends are fixed between one flange (3) and a hollow
cylindrical drum (4) inside which the dragging ring (5) internally provided with a
crown gear (5a) is inserted and rotates; through the two grooves (4a) located in the
drum (4) the crown gear (5a) engages with two pinions (6) that are housed inside the
drum (4) and splined on threaded rods (7) - one right-hand and one left-hand - that
are subject to the axial thrust of their springs (8) and on which the corresponding
cursors (9) are screwed that work together with the limit switches (10) fixed above
their support bases (10a) anchored over the above-mentioned rods (2). 2) Device comprising
a box (11) with lid (11a) that is fixed and screwed onto the drum (4) and intemally
features housings and guides for a pair of pistons (12), with each piston that slides
along an orthogonal direction intersecting the longitudinal axis of one of the threaded
rods (7);. being provided that each piston (12) includes a stem (12a) that ends on
one side with a biting head (12b) and on the other side with a parallelepiped body
(12c) featuring a front niche with two grooves (12d and 12e) of different depth connected
by an intermediate inclined plane (12f); being also provided that the drum (4) and
the box (11) feature pairs of through holes (4b and 11b), respectively, that allow
the tips (7a) of the rods (7) to penetrate into the front niches of the pistons (12).