Patent Application
20100024160
The present invention comprises an automatic door-closing device for use on breakout sliding doors and patio sliding doors. In particular, a device according to the present invention will automatically close a set of sliding doors whereby a first door is intended to slide over, and proximate to, a second door. The device also handles a set of sliding doors that fully break out into an open position whereby the first sliding door is placed into an open position by sliding over, and proximate to, a second door, and then the set of both doors is opened with respect to a door frame.
1. Brief Description of the Related Art
Various prior art door-closing systems have been disclosed that self-close patio sliding doors with bottom tracks. Typically, these prior art devices utilize cylindrical tubes having a weight that is connected to a cable, the cable passes over a pulley, and the pulley is anchored in the doorjamb. Each of these door-closing systems utilizes a valve means at the bottom of the tube to control the flow of air passing therethrough.
Typical prior art sliding door closers are disclosed in U.S. Pat. No. 3,334,444 to Hargrove (hereinafter, “the '444 Patent”), and U.S. Pat. No. 4,884,369 to Tatham (hereinafter, “the '369 Patent”). As with typical prior art devices, the '444 Patent and the '369 Patent teach that when a door is opened, a weight rises in the tube; when the door is released, the weight drops in the tube according to the port adjustment in the tube, and the door closes. (See the '444 Patent, Column 5, Lines 54-61; and the '369 Patent, Abstract).
Another prior art device, U.S. Pat. No. 4,649,598 to Kinsey, et al. (hereinafter, “the '598 Patent”), utilizes a weight and pulley system such as that described above with respect to the '369 Patent, together with a pneumatic seal located at the top of the weight and designed to buffer the speed at which the door closes. (See the '598 Patent, Column 3, Lines 47-56).
However, none of the prior art devices provide an automatic door-closure mechanism for a set of sliding doors that permit the sliding doors to fully break out into an open position whereby the first sliding door is placed into an open position by sliding over, and proximate to, a second door, and the set of both doors is opened with respect to a door frame.
As an example, there remains a need within hospitals that utilize trackless breakout sliding doors in Intensive Care Units (ICU). These doors allow ICU rooms to maintain a negative pressure which is required because the hospitals are utilizing these rooms as isolation units for persons with a contagious disease. One way to have these rooms pressurized is to have the doors closed all of the time. In recent years, the demand for the automatic self-closing device has become more prevalent.
In other situations such as clean rooms, there also is a need for this self-closing device to inhibit the entry of dust and other particles into the clean room. It is has been found that clean rooms also can be negative pressure rooms. Alternatively, automatic self-closing doors might be desirable to keep particles or odors inside a room such as in laboratories where there is chemical testing, mixing, and any odors that are unwanted in other areas of the facility.
An automatic self-closing device also provides an appropriate fire door protection where typical trackless sliding doors may be used. When the smoke detectors and alarms go off, a magnet will disengage and the door closure device will automatically close the door panel to cut down on drafts from one area.
With hotels, homes, and office buildings, there is a need for a more efficient closing device for the sliding door. An improved automatic closing device for sliding doors will improve energy efficiency, convenience, security, and safety. Any improvement in self-closing doors known in the prior art will therefore be an improvement in these areas as well.
Based on the shortcomings of the prior art described above and other known prior art, the object of this present invention is to provide an automatic closing device for both the trackless breakout sliding door and the patio sliding door. Another object of the present invention is to provide additional unique features for an automatic closing device including a novel pulley housing, alternative cable fabrication material, alternative means for attaching the cable to the trackless breakout sliding door, alternative pulley housing fabrication material and alternative weighted piston fabrication material.
2. Description of the Invention
The present invention comprises an automatic door-closing device used on trackless breakout sliding doors typically installed in hospitals for ICU doors, clean room facilities, fire doors, and laboratories. This automatic door-closing device also can be used on patio sliding doors for energy efficiency, convenience, security, and safety of having a patio sliding door automatically closed.
A door closing device system 10 according to the present invention is shown in
As shown in Detail A, a bearing-mounted pulley housing 18 is mounted on to the top portion 20 of cylinder 12. As shown in Detail B, cable 22 is anchored into cable anchor housing 24. Cable anchor housing 24 is mounted on the top face 26 of the sliding door panel header 28 (not on the sliding door 16) and substantially flush with the front face of header 28. Cable 22 can be anchored within cable anchor housing 24 by any number of known means.
As shown in
As depicted in
Other features shown in
As further shown in
A rubber U-cup 40 is mounted at the bottom of weight 38. U-cup 40 flairs out when weight 38 is rising and keeps weight 38 sealed to the inside of cylinder 12. Conversely, as weight 38 is dropping, pneumatic seal U-cup 40 compresses air down through the valve assembly 30 to seal off the weight to the inside of the cylinder below the weight. The air is regulated through a check valve set screw that may be turned in and out to let more air out or less air out which controls the speed of the door.
Cable 22 may be attached to weight 38 by any one of a number of known means. In the embodiment taught herein and shown in
As described hereinabove and shown in
Bearing-mounted pulley housing 18 has been designed for the trackless breakout sliding doors because these doors also hinge. In addition, this design also can be used with a regular sliding patio door to accommodate proper alignment with the anchoring point of the cable. Bearing-mounted pulley housing 18 rotates in relation to cylinder 12 when the door breaks out or is in a hinging position. This new design contains a vertical needle bearing 46 that is inserted into cylinder 12. Bearing-mounted pulley housing 18 in turn is positioned within vertical needle bearing 46. A second pulley assembly 47 is mounted on an axle within bearing-mounted pulley housing 18 to center the cable 22 for positioning within bearing-mounted pulley housing 18.
Returning to in
In a preferred embodiment of the invention, bearing-mounted pulley housing 18 comprises pulley 50 which, in turn, comprises a ball bearing assembly 51 rotateably mounted on mounting axle 53. This embodiment introduces far less friction into the system than any prior art device and reduces wear of all of the related components passing therethrough.
The bearing-mounted pulley housing also allows the sliding door panel to move into a breakout position without any damage to the cable. Similarly, the mechanism permits the sliding door panel to return to a properly aligned position when the door is put back into the sliding position without requiring any mechanical adjustments. When the sliding door panel is broken out of the header frame, the door is opened all the way causing the cable to stretch. With the door closing systems presently known in the art, the door could scrape the bottom edge of the cable and fray the cable. The bearing-mounted pulley housing design of this present invention eliminates that problem by actually rotating the cylindrical tube with respect to the sliding door when the door breaks out.
The bearing-mounted pulley housing design also can be used with a regular sliding patio door to accommodate the proper alignment with an anchoring point of the cable. With conventional sliding patio doors, door closer clips have to be installed to create a proper alignment with the anchoring point of the cable. This can be unsightly. The bearing-mounted pulley housing solves this problem.
One embodiment of a bearing-mounted pulley housing according to the present invention, and in further contrast to the prior art, is that the pulley housing is fabricated from aluminum rather than plastic. It is found to be efficient while allowing the cable to run true with the least amount of friction. In addition, with a unit fabricated from aluminum, there is less wear and tear on the cable because of the strength of aluminum in comparison to plastic.
Another embodiment of the present invention comprises the means for attaching the cable to the cable anchor housing. Prior art means for attaching a cable to a cable anchor housing comprise an eyelid connector for the cable. To eliminate the potential of cable connection breakage, the present invention comprises an off-set aluminum block with a through bolt to fasten the block to the door and to loop the cable around the inner shaft of the bolt. Therefore, when the cable is wrapped around the stand off and comes back out through the guide hole, it is connected with a nickel press and ties off in a slipknot. This prevents the problems found with the prior art designs by eliminating any sharp corners that could eventually break the cable.
In a preferred embodiment of the present invention, the cable used is a fiber cable rather than steel. This fiber cable has been effective under a 360-pound test. The weight used for the closing device is only about 3.5 pounds therefore there is no concern for breakage of the cable. The cable also is preferred because it is very flexible and very slippery thereby causing very little friction and creating a long life expectancy for the cable.
A preferred embodiment of the present invention comprises a weight wherein the weight in turn comprises solid steel. Other prior art devices have used a drawn aluminum; however, a solid steel weight is found to be much cleaner than the drawn aluminum weight. The drawn aluminum tube weight used by others contains lead and potentially additional lead shot if needed. That method is found to be very messy and much harder to install and/or repair. By utilizing a solid steel weight with this new self-closing device, it is found to be more successful and much cleaner to install and/or repair. For hospitals, clean room facilities, and residential usage, a cleaner more efficient weight is preferred.
The automatic door-closing device of the present invention overcomes the shortcomings of the prior art. Although the invention has been described in considerable detail with respect to particular embodiments of Applicant's automatic door-closing device, it will be apparent that the invention is capable of numerous modifications and variations, apparent to those skilled in the art, without departing from the spirit and scope of the invention.
