Patent Grant
6847136
The invention relates to motorized door opening systems such as those that use an electrical motor that drives a gear system or some sort of linkage to open and close a garage door in a residence or another structure.
Motorized garage door opening systems are well-known and in wide use. Such systems often include an electric motor connected to a gear system, which is connected in turn to a chain, belt, or screw that is linked to the garage door. Driving the motor in one direction opens the door; driving it in the other direction closes the door.
Such systems are popular and convenient because they spare the user the physical effort of opening and closing the door, and when used with a remote control system, the user can open and close the door without leaving his or her vehicle. Some such systems are less than ideal, though, because the electrical motor necessarily produces a certain degree of noise and vibration, and these can be transmitted to the structure to which the motor is mounted. Vibration can also be transmitted to the unit's cover, and radiated from the cover into the surrounding environment. These noises can travel into the interior of the structure, which can disturb others inside the building. Efforts have been made to make the motors and their associated gears and linkages as quiet and smoothly operating as possible, but in many cases more could be done.
It would be desirable, therefore, to devise a system for isolating a drive motor in a door opening system from the structure to which the motor is mounted. Such a system should effectively isolate the motor to decrease the noise and vibration transmitted from the motor to the mounting structure. Such a system should also be simple and inexpensive to manufacture, install, and maintain, so as not to interfere unduly with the system's ease of installation and use. The invention provides such an isolation system—one that offers these and other advantages that will be appreciated more fully with reference to the following written description and the drawings that accompany it.
The invention is embodied in a drive assembly in a motorized door opener for use especially with an overhead door for a residential or commercial garage. The drive assembly includes a motor that is mounted on a mounting structure. At least one vibration isolator is provided between the motor and the mounting structure. The vibration isolator includes a first mounting fastener configured to be mounted to a mounting fastener on the motor, a second mounting fastener configured to be mounted to the mounting structure to mount the motor on the mounting structure, and an elastomeric material between the first and second mounting fasteners. The elastomeric material lies between the first and second mounting fasteners so that the two mounting fasteners are not in physical contact.
In a particularly preferred embodiment, the motor may be delivered to an assembly site with nuts preinstalled on mounting screws the extend from the motor's housing. The nuts on the motor have threads compatible with mounting screws on the vibration isolator, and the vibration isolator has embedded mounting nuts with threads compatible with the motor's own mounting screws. To install such a motor on a mounting structure, the installer first removes the nuts from the motor's mounting screws, and installs the vibration isolators in their place. The installer fits the vibration isolator's mounting screws to holes provided in the mounting structure, and then screws the nuts onto the isolators' mounting screws to mount the motor onto the mounting structure with the isolators between the motor and the mounting structure.
The invention is described here in connection with a garage door opener that includes an electrical motor configured to open and close a garage door.
The motor 12 is secured to a mounting structure 15, which in this embodiment includes a vertical mounting plate 18. The mounting plate is mounted in turn to a horizontal mounting tray 20, with the motor suspended on the mounting plate with respect to the mounting tray. A cover, which is omitted from this figure for clarity, mounts to four cover mounting points 23 so that the motor is enclosed inside a cover assembly comprising the mounting tray 20 and the cover.
The motor 12 includes a motor housing 25, which is generally cylindrical in this embodiment. A motor shaft 28 extends out of the motor housing on one side of the motor, with a worm gear 30 mounted on the rotating motor shaft. The worm gear meshes with a spur gear 33. Together, the worm gear 30 and the spur gear 33 form a worm gear set. The spur gear drives a gear shaft 35, which extends through the mounting tray 20 of the operator's housing, as can be seen in the side view of the system shown here as
The operator 10 is mounted to the building structure, generally by hanging the operator on a bracket or some similar member mounted securely to the structure of the building. The gear shaft 35 is connected to a drive train, which typically includes a belt, chain, or screw that is connected in turn to a linkage mounted on the movable door. Driving the motor 12 in one direction moves the belt or chain to open the door; driving the motor in the other direction closes the door. This much of the system is generally conventional, and such systems and variants will be familiar to those of skill in the art.
The motor 12 is mounted to the mounting plate 18 via four vibration isolators 37. Two of these isolators are visible in
As
The other end of each vibration isolator 37 includes an isolator mounting screw 49, which is provided with external threads 50 where the isolator mounting screw extends out of the elastomer 43. The embedded nut 45 and the isolator mounting screw 49 are both embedded in the elastomer 43, with a central region 52 of the elastomer between them so that the embedded nut and the isolator mounting screw are separated somewhat by the elastomer and not in direct physical contact with one another.
To install the motor 12 onto the mounting plate 18 of the mounting structure 15, the embedded nuts 45 of the vibration isolators 37 are screwed onto the motor mounting screws 41 that project from the motor housing 25. The vibration isolator's mounting screws 49 are inserted through holes provided in the mounting plate, and the nuts 40 are then tightened onto the threads of the vibration isolator's mounting screws to mount the motor onto the mounting plate.
The nuts 40 may be present on the motor mounting screws 41 of the motor 12 before the motor is installed in the drive assembly. In that case, the motor mounting screws 41 will have the same style threads as the isolator mounting screws 49, and the nuts 40 will have the same style threads as the embedded nuts 45 in the isolators 37.
Before installing the isolators 37, the user will first remove the nuts 40 from the motor's mounting screws 41. The nuts 40 will be set aside for the moment, and the isolators' embedded nuts 45 screwed onto the mounting screws 41 of the motor 12. The isolators' mounting screws 49 can then be inserted through the holes in the mounting plate 18, and the nuts 40 retrieved and screwed onto the isolator mounting screws to secure the motor to the mounting structure 15.
The elastomeric material may be natural rubber or a synthetic equivalent such as neoprene or silicone. The elastomer may generally have a hardness somewhere in the range of about 30 to about 55 Durometer (Shore A), preferably between about 40 and about 50 Durometer (Shore A), with the hardness and geometry selected to provide adequate rigidity for a secure motor mount, combined with acceptable isolation of the motor from the mounting structure and adequate damping of noise and vibration.
Such an assembly includes at least one vibration isolator between the motor housing and the mounting structure. Two vibration isolators spaced apart from one another are better, three are better still, and four are used in the preferred embodiment described in this document.
The material and configuration of the isolators should be selected to provide effective isolation and damping of the vibration and noise produced by the motor. In general, softer materials will provide better isolation than stiffer ones. It is important, though, to avoid resonance in the system by configuring the system so that the system's natural frequency is not near the driving frequency of the motor.
Springs—coil springs, leaf springs, or other flexible members—could be used as vibration isolators instead of the elastomeric materials described above. Virtually any type of flexible or deformable material might be configured to isolate the motor's vibration from the structure it is mounted to. Elastomeric isolators are advantageous, though, in that they can provide a significant degree of energy absorption, or damping, as well.
In an assembly of the type described in this document, bearing members may be used around the motor shaft 28. In a prototype embodying the invention, it has been found helpful to include bushings 55 (see
Various modifications and additions to the preferred embodiment described in this document will occur to those of skill in the art. The scope of the invention is not limited to the details of this preferred embodiment. The scope of the invention should be determined instead primarily by reference to the appended claims, along with the full scope of equivalents to which those claims are legally entitled.
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| Number | Date | Country | |
|---|---|---|---|
| 20040189107 A1 | Sep 2004 | US |
