Device for motorizing an overhead swinging door for a garage or the like, and motorized overhead swinging door provided with this device

An overhead swinging door is swingably mounted on two side supports slidable in two vertical guides and each connected to a counterweight by a cable re-directed over an upper pulley. On at least one of the door sides, the counterweight is also connected to the respective side support by a chain which forms an endless ring with the cable and is re-directed over a lower wheel driven by a motor and reducing gear unit which is preferably located within the side upright of the door frame.

BACKGROUND OF THE INVENTION 
The present invention relates to motorized overhead swinging doors for 
garages and the like, of the known type comprising: 
a fixed support frame, including two side vertical guides, 
two side supports, movable within said side guides, 
a door structure, swingably mounted around a horizontal axis on said side 
supports and also connected to the fixed frame by two pivoted side arms, 
a pair of counterweights, slidably along a vertical direction within said 
fixed frame and each connected to a respective one of said side supports 
by cable means re-directed over a respective upper pulley having a fixed 
axis, and 
an engine unit for driving the door. 
The doors of this type which have been produced up to now have motorized 
control mechanism which are relatively complicated and costly, also 
requiring long and complicated operations to be adapted on doors which are 
not orginally provided with a motorized control. 
SUMMARY OF THE INVENTION 
The object of the present invention is that of providing a motorized 
overhead swinging door which has a very simple and economic structure and 
which at the same time is efficient in operation and reliable. 
A further object of the invention is that of providing a device for 
motorizing overhead swinging doors which is simple and economic and may be 
adapted with a few and simple operations on doors which originally are not 
provided with a motorizing device. 
In order to achieve said first object, the invention provides a motorized 
overhead swinging door of the type which has been indicated above, 
characterized in that at least one of said counterweights is connected to 
the respective side support both, on the upper side, by said cable means, 
and, on the lower side, by chain means which form an endless ring with 
said cable means, said chain means being re-directed around a respective 
lower wheel, said engine unit being arranged to drive said lower wheel. 
Due to said features, the invention allows a dramatic reduction in the 
costs and complexity of the motorizing device with respect to the 
solutions provided up to now, and further ensures a very high reliability 
and easiness of mantainence. 
The invention is applicable to any type of overhead swinging door, also 
with a different balancing arrangement and for any use (for a garage or 
others). 
It is to be submitted, furthermore, that the terms "cable means" and "chain 
means" which appear in the present description and in the following claims 
are intended to indicate any transmission element equivalent to a cable or 
a chain. 
The above described arrangement may be adopted on one side only or on both 
sides of the door. 
In a preferred embodiment, the door according to the invention is further 
characterized in that it includes a bolt device driven by a solenoid for 
locking the door in the closed condition. Preferably, the bolt device 
includes a bolt carried by the fixed frame and a coupling element for 
cooperation with the bolt carried by the door, said bolt being elastically 
biased into its closed position and being movable towards the opened 
position by solenoid control means. When the door is locked, this coupling 
element can be retracted towards a bolt disengaging position by a manually 
operable mechanism, so as to allow the opening of the door in case of an 
interruption of supply to the solenoid control means. Said manually 
operable mechanism includes a key-operable latch and may be the 
conventional mechanism with which any non-motorized overhead swinging door 
is provided. 
The invention obviously also provides the motorizing device per se, which 
can be adapted on a overhead swinging door which is not originally 
provided with a motorized device.

DETAILED DESCRIPTION OF THE INVENTION 
In FIG. 1, reference numeral 1 generally designates an overhead swinging 
door according to the prior art, which is not provided with a motorizing 
device. The door 1 comprises a door structure 2 swingably mounted around a 
horizontal axis on two side supports 3 which are movable in two vertical 
side guides 4 forming parts of the fixed frame of the door. In FIG. 1, the 
closed vertical position of the door is shown by undotted line, whereas by 
dotted lines there are indicated the opened horizontal position and an 
intermediate position. 
The door is also connected to the fixed structure by two side arms 5 each 
pivoted in 6 to the fixed structure. The opposed end 7 of each arms is 
pivoted to the door 2 and is therefore constrained to move along a 
circular path 8. 
Each side support 3 is also connected to a respective counterweight 9 by a 
metal cable 13 which is re-directed around an upper pulley 10 freely 
rotatably mounted on the fixed structure around a horizontal axis 11. The 
door 1 is also provided, in the usual way, with a handle 21 for the manual 
opening and closing operation, as well as with a key-operable latch for 
locking the door in the closed position. 
In the example shown in FIG. 2, a door of the type of FIG. 1 is motorized 
simply by connecting at least one of the two side supports 3 to the 
respective counterweight 9 by a chain 12 of rollers which forms an endless 
ring with cable 13. The chain 12 is in engagement with a lower pulley 14, 
having an axis 15 parallel to the axis of the upper pulley 10. The pulley 
14 is mounted on the output shaft of a motor and reducing gear unit 16, 
including an electric motor and a screw-wheel reducing unit, for example 
of the type used for driving electric car windows. 
Since the door is balanced by counterweights 9, the motor and reducing unit 
can have a low power. Activation thereof in either direction cause the 
lowering or raising respectively of counterweights 9 and consequential 
opening or closing of the door. 
The embodiment of FIG. 2 is also visible in perspective view in FIG. 3, 
which clearly shows that the above described arrangement is provided only 
on one side of the door and is located inside the upright forming part of 
the fixed frame of the door and containing the counterweight. However, it 
is also possible to provide the same arrangement on both sides of the 
door. FIG. 3 shows also a bolt device for locking the door in its closed 
condition. This device comprises a bolt 18 driven by a solenoid 17, which 
is visible in an enlarged scale in FIG. 4. The inner construction details 
of this device are not shown since they can be of any known type. The 
device 17 is mounted on the fixed structure over the door. The bolt 18 
cooperates with a coupling element 19 carried by the door in order to lock 
the latter in the closed position. The bolt is biased by spring means (not 
shown) into the position engaging element 19 and can be disengaged from 
the latter by a solenoid control device of the type usually used in 
electric door latches. The coupling element 19 is not mounted in fixed 
position on the door 2, and can be moved away from engagement with the 
bolt by a mechanism 20 with a handle 21 provided with a key-operable 
latch. Thus, it is possible to open the door when the latter is locked and 
an interruption of power supply has occurred. The handle may be that 
usually provided in all non-motorized overhead doors. 
The door according to the invention is preferably provided with a safety 
device of any known type, as a friction coupling on the shaft of the motor 
and reducing unit or with a device for controlling the current absorption 
of the motor, in order to protect the system and as a safety measure in 
case anything prevents the movement of the door. In case a torque limiting 
friction coupling device is used, this device is preferably of the type 
which allows the maximum transmissable torque to be adjusted. 
Naturally, the principle of the invention remaining the same, the details 
of construction and the embodiments may widely vary with respect to the 
described example.