60/239,768 filed October 13,2000.

FIELD OF THE INVENTION [0002] The present invention is related to a mechanism that allows wheelchair operators to open a fire door with the lower portion of their wheelchair assembly.

BACKGROUND [0003] Currently, there is no way for a mobility impaired individual, confined to an electrically driven wheelchair and without assistance, to re-open a fire door once it closes. This could result in this person becoming trapped during an emergency, particularly when working after normal working hours when the building occupancy is low.

[0004] Most electrically driven wheel chairs are very maneuverable and are equipped with one or two rams located at footrest height which are used for various purposes. These rams can be utilized to apply a forward force against a door. If a latch releasing mechanism were to be placed at ram height, then a wheelchair operator could open a fire door without assistance.

[0005] What is needed is a latch releasing apparatus on a fire door that permits a wheelchair operator to open a closed and latched fire door without assistance using a ram positioned near the wheelchair footrest.

SUMMARY [0006] The present invention is comprised of a series of linkages that transfers the energy of a push on a bar located near the bottom edge of a fire door to an actuating bar located at the middle of the door. A wheelchair operator merely pushes on the door with the wheelchair ram as he/she would any other door. A lower actuating bar compresses with a minimum of pressure thus disconnecting the latching device and permitting the wheelchair operator to pass unassisted.

BRIEF DESCRIPTION OF THE DRAWINGS [0007] FIGURE 1 is an edge elevation view of the present invention as it is implemented onto a fire door.

[0008] FIGURE 2 is a more detailed illustration of the linkage apparatus on the lower bar.

[0009] FIGURE 3 is a more detailed illustration of the linkage apparatus on the upper actuating bar.

DETAILED DESCRIPTION [0010] Existing fire door hardware is constructed with a single actuating bar that is mechanically coupled with a latch. The latch, in turn, engages and disengages a strike on the door jamb.

When the latch is engaged, the fire door cannot be pushed open. When the latch is disengaged, the fire door can be pushed open. Typically, the actuating bar is positioned approximately waist high allowing a person to comfortably reach out their arms and hands to depress the actuating bar and release the latch. This waist high position also allows the person opening the door to continue pushing the door open once the latch has been released without having to move their arms.

[0011] The mechanism described above is a convenient apparatus for those without physical disabilities. However, many physically disabled wheelchair bound individuals either work in or attend functions in buildings that possess these fire doors. Often, these people are unable to operate a fire door latch mechanism described above due to their disability. This presents a significant problem when such individuals are alone. The problem can be as innocent as an inconvenience while waiting for assistance or as dangerous as being trapped behind a fire door in an emergency situation.

[0012] Typically, an actuating bar on a fire door must be depressed by a distance of one half of an inch to release the latching devices. The mechanical couplings between the upper actuating bar and the latch mechanism per se are not at issue with the present invention. For purposes of the present invention, it is assumed that actuation of the upper actuating bar by the requisite distance will disengage the latch mechanism. Thus, the present invention is comprised of an additional bar located much lower on an existing fire door at wheelchair ram height that is mechanically coupled to the upper actuation bar through a series of linkages. The apparatus is designed to transfer the energy from the lower bar to the upper actuation bar such that a force applied to the lower bar will release the latch mechanism coupled with the upper actuation bar.

Since the lower bar is positioned at a height above the floor that corresponds with a wheelchair ram, a wheelchair operator can now gently ram his or her wheelchair into the lower bar and cause the latch to release. Once the latch is released, the wheelchair operator may continue to use the wheelchair to move forward through the door.

[0013] FIGURE 1 is an edge elevation view of the present invention as it is implemented onto a fire door 10. Fire door 10 includes a lower bar 20 and a upper actuating bar 30. The upper actuating bar 30 is mechanically coupled to a latch/strike mechanism (not shown) such that when upper actuating bar 30 is actuated, the latch mechanism will release from the strike allowing the door to be opened. Upper actuation bar 30 and lower bar 20 are also mechanically coupled together via a linkage apparatus that is comprised of a linkage 40 coupled with a pair of bellcranks 60a, 60b. Linkage 40 is comprised of an adjustable threaded rod that is threaded on both ends and coupled with a pair of threaded rod couplings 21a, 21b. Linkage 40 is covered by a linkage cover 50 that acts to cover and protect linkage 40.

[0014] FIGURES 2 and 3 are detailed illustrations of the linkage apparatus on the lower bar 20 and upper actuating bar 30. A lever assembly 22 is installed inside of lower bar 20. The lever assembly 22 operates at a 1 to 11/4ratio. This ratio ensures that the upper actuation bar 30 will move one half an inch when the lower bar 20 is depressed the same distance. When lower bar 20 is depressed, lever assembly 22 pulls an adjustable threaded rod 24 which is connected to a threaded rod coupling 21c. Threaded rod coupling 21c is coupled with bellcrank 60a via a pin assembly 26. Bellcrank 60a is caused to rotate counterclockwise. Lower bellcrank 60a is also coupled with linkage 40 via another pin assembly 28. Linkage 40 provides the coupling between lower bellcrank 60a and upper bellcrank 60b. Thus, when bellcrank 60a rotates counterclockwise, linkage 40 is pulled downward. Since linkage 40 is also coupled with upper bellcrank 60b via pin assembly 32, a downward motion of linkage 40 causes upper bellcrank 60b to rotate counterclockwise. When upper bellcrank 60b rotates counterclockwise, it in turn pulls a threaded rod coupling 21d that is coupled with adjustable threaded rod 34. Adjustable threaded rod 34 is coupled with upper actuating bar 30. Upper actuation bar 30 is actuated by this motion thus disconnecting the latching mechanism and allowing the fire door to be pushed open. Adjustable threaded rod 34 is coupled with bellcrank 60b via threaded rod coupling 21d and pin assembly 36.

[0015] When the door is opened by pushing on upper actuation bar 30 instead of lower bar 20, the linkage apparatus does not transfer the energy down to lower bar 20. This is due to a slot 38 included on bellcrank 60b that allows adjustable threaded rod 34 to move freely in one direction without causing bellcrank 60b to rotate.

[0016] The use of adjustable threaded rods for the linkages allows for the present invention to be adapted to a variety of door sizes without having to custom fit each linkage to each door. The length of the adjustable threaded rods can be controlled by threading the rod a desired distance using the threaded rod couplings 21a-d. The invention can, however, be practiced without the use of adjustable threaded rods. Fixed length rods can be substituted for the adjustable threaded rods without departing from the sprit or scope of the present invention.

[0017] In the following claims, any means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents but also equivalent structures. Therefore, it is to be understood that the foregoing is illustrative of the present invention and is not to be construed as limited to the specific embodiments disclosed, and that modifications to the disclosed embodiments, as well as other embodiments, are intended to be included within the scope of the appended claims. The invention is defined by the following claims, with equivalents of the claims to be included therein.