ELECTROMAGNETIC ACTUATOR FOR DOOR UNITS AND THE LIKE

Abstract: An electromagnetic actuator for door units and the like, particularly for up-and-over doors, characterised by comprising: a tubular guide (18) comprising at least two parallel side-by-side rectilinear portions (22, 24), a flexible rack (16) consisting of a metal wire spirally wound about a flexible core and housed partly within one rectilinear portion (22) of the guide (18) and partly within the other (24) such that it can undergo axial sliding, a geared motor unit (2, 8, 10, 12) provided with a gearwheel (14) engaging the flexible rack (16) via an aperture (28) provided in at least one of the two rectilinear portions (22, 24) of the tubular guide (18), at least one hanger (34) fixed to said flexible rack (16) and emerging via an appendix (32) through a continuous longitudinal slot (30) provided in at least one of the two rectilinear portions (22, 24), and members (36) for mechanically connecting the hanger appendix (32) to the element (26) to be moved.

Description: Electromagnetic actuator for door units and the like This invention relates to an electromagnetic actuator for door units and the like, particularly for up-and-over doors. Devices for opening and closing up-and-over doors are known. One of these comprises a geared motor fitted to the up-and-over door and provided with a transversely extending exit shaft connected by articulated vertical arms to couplings rigid with the uprights of the door frame. Rotation of the geared motor causes the articulated arms to rotate about the corresponding frame couplings, with consequent opening and closure of the up-and-over door. A drawback of this known device is its difficulty of installation, which requires several operations on the up- and-over door for fitting it with external members such as the supports for the geared motor, the support bushes for the transverse shaft, the articulated arms and the relative couplings on the door frame. A further drawback is that these members increase the weight of the entire door and therefore require adjustment of the counter-weights or the compensation springs to counterbalance said weight. A further drawback is that the transverse shaft does not allow a usual inwardly opening small service to be applied to the up-and over door. A further drawback is that up-and-over doors of different width require transverse shafts of corresponding length, with the evident impossibility of constructing standardized operating devices applicable to any up-and-over door. To obviate these drawbacks an up-and-over door operating device has been proposed comprising a rail to be fixed to the room ceiling to the up-and-over door and able to guide a trolley connected to the door upper cross-member by an articulated bar. The trolley is driven by a belt or chain extending between two sprockets, one of which is driven, so that rotating the motor in one or the other direction causes the trolley to travel along its guide and hence open and close the up-and-over door. The drawback of this arrangement is a certain constructional complexity due to the large number of components (articulated bar, trolley, trolley guide, chain, chain tensioner, geared motor) and hence the high cost of the device plus the considerable labour involved in its installation. A further drawback is that the large number of moving parts, each of which is potentially subject to breakdown, means that its operation is not particularly reliable. As an alternative to the endless chain it has also been proposed to move the trolley along the guide by a threaded rod driven by a geared motor and engaging a threaded bush rigid with the trolley. In this manner the number of components and hence the installation complexity are reduced while at the same time increasing their reliability of operation, even if in practice the cost of the device plus its installation is not substantially different. An object of the invention is to obviate the aforesaid drawbacks by providing a device for operating up-and-over doors and door units in general, which is of low cost, easy and quick installation, reliable operation and universal use. This and further objects which will be apparent from the following description are attained according to the invention by an electromagnetic actuator for door units and the like, particularly for up-and-over doors as described in claim 1. Some preferred embodiments of the present invention are described in detail hereinafter with reference to the accompaying drawings, in which: Figure 1 is a schematic side view of an electromagnetic actuator according to the invention applied to an up-and-over door; Figure 2 is an exploded perspective view thereof; Figure 3 is an enlarged horizontal view thereof on the line III-III of Figure 1; Figure 4 is a cross-section therethrough on the line IV-IV of Figure 3; Figure 5 is a longitudinal section therethrough on the line V-V of Figure 3; Figure 6 shows a further embodiment thereof in the same horizontal view as Figure 3; Figure 7 shows a further embodiment thereof in the same view as Figure 3; Figure 8 is a cross-section therethrough on the line VIII- VIII of Figure 7; and Figure 9 is a longitudinal section therethrough on the line IX-IX of Figure 8. As can be seen from the figures, the electromagnetic actuator according to the invention comprises an electric motor 2, preferably powered by direct current via a control unit 4 and having a worm 6 keyed onto its exit shaft 8. The worm 6 engages a helical ring gear 10, on the shaft 12 of which there is keyed a gearwheel 14 engaging a flexible rack 16, consisting of a steel wire spirally wound at constant pitch about a flexible core in the form of a metal cord. The flexible rack 16 is housed within a tubular guide 18 fixed to the ceiling 20 and comprising two rectilinear portions positioned perpendicular to the upper cross-member of the up-and-over door 26 and joined together by a loop surrounding said reduction gear unit 6,10,12. One rectilinear portion 24 is completely closed whereas the other 22 comprises a lateral aperture 28, through which the gearwheel 14 engages the flexible rack 16, and a continuous longitudinal slot 30 along which there can slide the projecting arm 32 of a hanger 34 which is fixed to one end of the flexible rack 16 and is connected to the central part of the upper cross-member of the up-and-over door 26 by an articulated arm 36. The two rectilinear portions 22,24 of the tubular guide 18, which in Figures 5 and 6 are shown separate and in particular are formed by sending a straight tubular guide, in reality advantageously consist of two parallel longitudinal cavities of a single section bar formed for example of extruded aluminium, as is apparent from Figure 8. Specifically, this extruded section bar comprises a central longitudinal cavity, forming the tubular guide portion 22, and two cavities flanking the sides of this latter, one of which forms the other rectilinear portion 24 and the third 38 forms a service cavity for the passage of electric cables. In a position below the three cavities 22,24 and 38 there is provided a further cavity for guiding a slide 42 rigid with the hanger 34 fixed to the flexible rack 16. The slide 42, the cross-section of which is overall complementary to the cross-section of the cavity 40, in reality comprises a block with two inclined surfaces, between which there is a seat 44 in which there snap-engages elastically, by the effect of a spring 46, a pin 48 provided in a second slide 50 slidable along a longitudinal cavity 52 formed in the same section bar in a position below the longitudinal cavity 40. The pin 48, which as stated is elastically maintained in engagement with the seat 44 provided in the slide 42 by means of a spring 46, can be operated from the outside by means of its appendix 54, which is provided with a hooking ring. The slide 50 is provided with a lug 56 for connecting that end of the articulated bar 36 not fixed to the up-and-over door 26. As this embodiment of the actuator according to the invention makes continuity of the tubular guide 18 essential, the two rectilinear portions 22,24 must be connected together at the end distant from the up-and-over door 26 by a rigid tubular connection element within which the flexible rack 16 can slide and be guided. For installing the actuator according to the invention the procedure is as follows: if the tubular guide 18 is in the form of pieces of section bar, these pieces are firstly joined together to facilitate packaging and transport. This is easily accomplished because each piece is provided with two longitudinal cavities 58 into which blocks or plugs 60 can be inserted, to then be fixed by screws to the two pieces of section bar to be connected together. A bracket 62 for securing the front end of the tubular guide 18 is then fixed to the lintel 61 upperly bounding the space within which the up-and-over door is applied, and a further bracket 64 for holding the box 66 housing the geared motor unit 2,6,8,10 the control unit 4 and a possible emergency electrical battery 67 is fixed to the ceiling. The actuator according to the invention, comprising the tubular guide 18 and the box 66, is then fixed to the two brackets 62 and 64, and the articulated bar 36 is fixed at one end to a bracket 68 previously fixed to the up-and-over door 26 and at its other end to the lug 56 on the slide 50. If during installation it is found that the tubular guide 18 is too long, it can be shortened to the required length very easily by simply cutting off a piece of the section bar and a corresponding piece of the flexible rack 16. During operation the rotation of the electric motor 2 causes the gearwheel 14 to rotate, resulting in axial sliding of the flexible rack 16 along the tubular guide from one rectilinear portion 22,24 to the other. As the slide 42 is applied via the hanger 34 to the flexible rack 16 and this slide is fixed to the slide 50 which is connected to the up- and-over door 26, it is apparent that rotating the electric motor 2 in one or the other direction causes the up-and-over door 26 to open and close. Traditional travel limiting systems, consisting for example of microswitches applied to the tubular guide 18 or forming part of the operational logic of the control unit 4, enable the electric motor to be operated only between the open and closed positions of the up-and-over door. If the electric power should fail, it is necessary merely to pull on the pin 48 in order to release the slide 50 from the slide 42 fixed to the flexible rack, and then manually move said slide 50 along the corresponding guide 52. To again mutually engage the two slides 50 and 42 it is sufficient to move the slide 50 towards the slide 42 until, after sliding along one of its inclined surfaces, the pin 48 snap-engages securely in the seat 44 provided between them. It is apparent from the aforegoing that the electromagnetic actuator according to the invention is extremely advantageous compared of a very small number of part, it is of very low cost, is quick to install and is of reliable operation. With regard to the small number of parts, these consist substantially of a plate on which the control unit 4, the geared motor unit 2,6,8,10 and possibly the electric battery 67 for emergency operation are mounted, the tubular guide 18 and the bar 36 for connection to the up-and-over door 26. The small number of parts obviously results in a device of low cost and of considerable operational reliability. With regard to quick installation, it is sufficient firstly to assemble the actuator on the ground in the already described form, then fix the bracket 62 to the lintel 61, then fix the end of the device guide 18 to said bracket 62, and then fix the device to the ceiling 20 by the bracket 64. Finally, after applying the bracket 68 to the up-and-over door 26 the articulated bar ! 36 is mounted between said bracked 68 and the slide 50 of the actuator. This is all - 10 - achieved by simple operations which can be effected independently of each other, without risk of error and with the certainty of being able to adapt the device to up-and- over doors practically of any size. In the embodiment shown in Figure 6, that portion of the tubular guide 18 connecting the two rectilinear portions 22,24 together is replaced by a plurality of idle rollers 70 arranged to cooperate with an idle guide pulley 72 so that the flexible rack 18 forms the loop connecting together the parts slidable within said rectilinear portions 22,24. Although this embodiment requires the rollers 70 and guide pulley 72, it eliminates the need for a continuous tubular guide between the two straight portions 22 and 24, and hence simplifies the formation of said tubular guide 18 while at the same time reducing friction, which is inevitably present along the loop formed by said flexible rack. In the embodiment shown in Figure 7 the loop formed by the flexible rack 18 is unguided, said flexible rack being engaged by the gearwheel 14 in both the rectilinear portions 22,24 of the tubular guide 18. In this case not only is friction practically eliminated along the loop of the flexible rack, but in addition the actuator construction is considerably more simple. In addition, from the operational viewpont this embodiment is particularly advantageous for operating with identical force two elements slidable in opposite directions. This makes the actuator of the invention suitable for use in operating oppositely sliding doors, curtains or the like. In this case both the rectilinear portions 22,24 of the tubular guide 18 must be provided with a continuous longitudinal slot, and a hanger 34 must be fixed to the flexible rack 16 at each of said rectilinear portions 22,24. If these two rectilinear portions form part of single section bar, as in the embodiment shown in Figure 8, the section bar should be provided with separate longitudinal cavities 40 for two separate slides connected to the two hangers.

Claims: C L A I M S 1. An electromagnetic actuator for door units and the like, particularly for up-and-over doors, characterised by comprising: - a tubular guide (18) comprising at least two parallel side- by-side rectilinear portions (22,24), - a flexible rack (16) consisting of a metal wire spirally w ound about a flexible core and housed partly within one rectilinear portion (22) of the guide (18) and partly within the other (24) such that it can undergo axial sliding, a geared motor unit (2,8,10,12) provided with a gearwheel(14) engaging the flexible rack (16) via an aperture (28) provided in at least one of the two rectilinear portions (22,24) of the tubular guide (18), 5 - at least one hanger (34) fixed to said flexible rack (16) and emerging via an appendix (32) through a continuous longitudinal slot (30) provided in at least one of the two rectilinear portions (22,24), and members (36) for mechanically connecting the hanger o appendix (32) to the element (26) to moved. 2. An actuator as claimed in claim 1, characterised in that the tubular guide (18) comprises a curved portion connecting together the two rectilinear portions (22,24). 3. An actuator as claimed in claim 1, characterised in that the tubular guide (18) is formed from a section bar comprising two longitudinal chambers constituting two rectilinear portions (22,24). 4. An actuator as claimed in claim 3, characterised in that the tubular guide (18) is formed from several section bar portions maintained in a mutually aligned state by blocks (60) fixed simultaneously to two adjacent section bar portions. 5. An actuator as claimed in claim 4, characterised in that the fixing blocks for adjacent section bars are pegs (60) inserted simultaneously into longitudinal cavities (58) in said section bars. 6. An actuator as claimed in claim 3, characterised in that the section bar forming the tubular guide (18) is provided with at least a third cavity (38) for the passage of cables. 7. An actuator as claimed in claim 1, characterised in that the geared motor unit comprises an electric motor (2) , on the exit shaft of which there is keyed a worm (6) engaging a helical ring gear (10) rotationally rigid with the gearwheel (14) engaging the flexible rack (16) . 8. An actuator as claimed in claim 3, characterised in that the section bar forming the tubular guide (18) is provided with a longitudinal cavity (40) for a slide (42) rigid with the hanger (34) fixed to the flexible rack (16) . 9. An actuator as claimed in claim 8, characterised in that the section bar forming the tubular guide (18) is provided with a second longitudinal cavity (52) for a second slide (50) removably connectable to the first slide (42) slidable within the longitudinal cavity (40) , members for mechanically connecting the hanger appendix (32) to the element (26) to be moved being fixable to said second slide (50) . 10. An actuator as claimed in claim 9, characterised in that the first slide (42) is provided with a seat (44) for releasable snap-engagement by an appendix rigid with the second slide (50) . 11. An actuator as claimed in claim 10, characterised in that the seat (44) provided in the first slide (42) is bounded by two inclined surfaces. 12. An actuator as claimed in claim 1, characterised in that with the two rectilinear portions (22,24) of the tubular guide (18) there are associated a plurality of rollers (70) arranged about a guide disc (72) to define a passage for the curved portion of flexible rack (16) beyond the two portions (22,24) of the tubular guide (18). 13. An actuator as claimed in claim 1, characterised in that the gearwheel (14) of the geared motor unit (2,6,8,10,12) simultaneously engages two points of the flexible rack (16) within the two rectilinear tubular guide portions (22,24) . 14. An actuator as claimed in claim 13, characterised in that that portion of flexible rack (16) not housed within the two rectilinear portions (22,24) of the tubular guide (18) forms a free loop. 15. An actuator as claimed in claim 13, characterised in that to each of the two portions of flexible rack (16) housed within the respective rectilinear portions (22,24) of the tubular guide (18) there is fixed a hanger (34) for securing the element (26) to be moved, the two elements being movable simultaneously in opposite directions.

Inventors: GIROTTO GIUSEPPE, SERAFIN GIOVANNI, GIROTTO, GIUSEPPE, SERAFIN, GIOVANNI
Applicants: GIROTTO GIUSEPPE, SERAFIN GIOVANNI, GIROTTO, GIUSEPPE, SERAFIN, GIOVANNI
Application year: 1993
Main classification: E05F15
IPC codes: E05F15