Patent Application
20100259053
1. Field of the Invention
The present invention relates to door hardware and, more particularly, a door handle attachment fixture that attaches a door handle to an escutcheon.
2. Description of the Background
In the door hardware industry, a common method of attaching a door handle to a mounting plate (or escutcheon) is to extend the hub of a door handle through an aperture in an escutcheon and then attach a C-clip or a retainer clip around the shank, securing the handle to the escutcheon. For example,
Other attachment fixtures have been attempted.
For example, United States Patent Application No. 2008/0111384 by Ellis published May 15, 2008, discloses an apparatus for retaining a spring and spindle in the shank of a door handle using a torsion spring and retainer ring.
U.S. Pat. No. 7,347,462 to Ellis et al. issued Mar. 25, 2008, discloses a door handle assembly in which the shank of the door handle extends through the aperture of the mounting plate and through two attached bearings. A retainer device, such as a push retainer, a snap ring, or a nut, secures the door handle to the mounting plate.
U.S. Pat. No. 7,188,873 to Brown et al. issued Mar. 23, 2007, discloses a door handle system with a removable locking fastener comprising a nut and a star washer having nubs that engage a groove in the handle. This door handle system, however, does not allow for precise adjustment, and the ears on the fastener must be bent to secure the nut.
U.S. Pat. No. 6,997,024 to Etlicher issued Feb. 14, 2006, discloses a pull door lock in which the shank is retained in the escutcheon plate by engaging a C-clip with a groove at the end of the shank.
U.S. Pat. No. 4,784,418 to Pearson et al. issued Nov. 15, 1988, discloses a door latch handle fitting. To secure the lever handle to the mounting plate, the shank of the lever handle is positioned through the aperture of the mounting plate, and the retainer is pressed onto the shank portion, engaging the gripping tongues with the shank.
U.S. Pat. No. 4,343,502 to Nelson issued Aug. 10, 1982, discloses a doorknob construction in which an externally threaded end of the door handle is inserted through an aperture in the mounting rose, and the door handle is secured by an adjustment bushing nut.
U.S. Pat. No. 4,042,268 to Coglan issued Aug. 16, 1977, discloses a latch or lock set in which the lever is retained to the back plate by slipping a retaining spring over the barrel into two groves on the barrel.
None of the foregoing references fully address the current problem, and instead of affixing a C-clip at a fixed position along the door lever hub, it would be greatly advantageous to provide an adjustable fixture with improved wear resistance and compact size, that can be adjusted and semi-permanently installed in the field.
The present invention is a door handle attachment fixture that pivotally attaches a door handle to an existing escutcheon. The door handle attachment fixture generally comprises a door handle with protruding hub for insertion through the escutcheon, a wear washer, a spindle nut, a spindle nut retainer, and a shaft retainer. The hub is externally threaded for engagement with the internal threads of the spindle nut, and has a central, longitudinal hole and axial slots. The axial slots engage with locking tabs of the spindle nut retainer. The wear washer is inserted over the hub between the inside surface of the escutcheon and the spindle nut. The spindle nut's internal threads are engaged with the threads on the hub, and the spindle nut is adjusted until the proper fit and feel is achieved. Because the spindle nut can be adjusted along the hub in minute fractions, it eliminates the need for tight tolerance components associated with C-clips or other retainer clips, and can be adjusted in the field. Once adjusted, the spindle nut retainer that conforms to the spindle nut's periphery is placed over the spindle nut, and locking tabs on the spindle nut retainer are engaged with the slots in the hub. This engagement prevents the spindle nut from rotating and backing off the hub. Finally, the shaft retainer is placed onto the hub over the spindle nut retainer to complete the fixture and create a semi-permanent installation. A keyed shank may be inserted into the longitudinal hole in the hub for operation of a locking or latching mechanism.
The spindle nut provides more contact surface area with the underlying wear washer, and this reduces cyclic wear and increases product life and reliability. Further, the door handle attachment fixture provides a lower profile plus a much stronger attachment, which increases product security.
Other objects, features, and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiments and certain modifications thereof when taken together with the accompanying drawings in which:
The present invention is a door handle attachment fixture that pivotally attaches a door handle to an existing escutcheon.
Referring collectively to
The door handle 20 comprises an exterior operator portion 21 which may take any conventional form including a lever (as shown), knob, or otherwise. The operator portion 21 is fixedly attached to the hub 22, so when a user grabs the operator portion 21 and applies rotational force, the hub 22 likewise rotates about its axis. The hub 22 further comprises an annular member terminating at a rim surrounding a longitudinal hole 24 aligned along the rotational axis of the hub 22. The hole 24 of the hub 22 accepts a shank (not shown) that transfers the rotational force to a locking or latching mechanism (not shown) installed in the door. The hole 24 is shown with a square periphery but may be otherwise keyed to the shank to ensure that the shank does not slip within the hole 24 while rotating.
The distal rim of the hub 22 is circumscribed by a tiered shelf 23 that protrudes outward from a larger diameter base 27 of the hub 22. The rim of hub 22 is further defined by opposing axial slots 25 that interrupt the rim at the distal end of the hub 22. While
The base 27 of the hub 22 is threaded with external threads. The threads may have an exemplary thread count of about 32 threads per inch. The hub 22 is positioned through the aperture of the escutcheon 30 and fitted with a wear washer 41 that fits over the base 27 of the hub 22. The wear washer 41 may be a flat polyethylene washer or other suitable plastic material. A spindle nut 42 is inserted onto the hub 22 over the wear washer 41. The spindle nut 42 may be a conventional hexagonal (or other polygonal shape) retaining nut as shown, and is internally threaded to conform to the threaded base 27 of the hub 22. To fasten the door handle 20 to the escutcheon 30, the spindle nut 42 is screwed onto the base 27 of the hub 22.
If desired, the escutcheon 30 may be formed with a concentric recess 32 surrounding the aperture to seat the wear washer 41. In this case, the diameter of the concentric recess 32 should be slightly larger than the diameter of the wear washer 41 to fully seat the wear washer 41. The depth of the recess 32 varies depending on the thickness of the front escutcheon surface. In addition, the wear washer 41 should be thicker than the depth of the recess 32 on the escutcheon 30 to ensure that the wear washer 41 and the spindle nut 42 maintain contact when the door handle 20 is rotated. Thus, the spindle nut 42 is isolated from the escutcheon 30, providing necessary wear resistance.
A spindle nut retainer 43 is then inserted over the spindle nut 42. The spindle nut retainer 43 comprises a concave hood that fits over the spindle nut 42, the concave recess being keyed to the periphery of the spindle nut 42 to prevent rotation. The illustrated embodiment of the spindle nut retainer 43 is a twelve-point retainer as best seen in
At installation, the spindle nut 42 is tightened onto hub 22 until the desired feel and fit of the door handle 20 is achieved. With the exemplary thread count, spindle nut 42 may be adjusted in about 0.0027″ increments. If the door handle 20 is loosely attached to the escutcheon 30, the spindle nut 42 should be tightened more. If the door handle 20 is too tight, the spindle nut 42 should be loosened in the opposite direction. Once the desired fit and feel is achieved, the spindle nut retainer 43 is placed over the spindle nut 42.
Finally, the shaft retainer 44 is pressed onto the rim of the hub 22 atop the spindle nut retainer 43 to secure the nut retainer 43, yielding the completed configuration as shown in
The hole 24 in the hub 22 remains open for insertion of a shank.
One skilled in the art will now see that the foregoing assembly pivotally attaches the door handle 20 to the escutcheon 30 without the need for tight-tolerance parts, because the spindle nut 42 can be adjusted in thousandths of an inch. This improves product security by providing a stronger attachment method, and the increased contact surface area of the spindle nut 42 with the wear washer 41 reduces cyclic wear and increases product life and reliability. When fully assembled as shown in
Having now fully set forth the preferred embodiment and certain modifications of the concept underlying the present invention, various other embodiments as well as certain variations and modifications of the embodiments herein shown and described will obviously occur to those skilled in the art upon becoming familiar with said underlying concept. It is to be understood, therefore, that the invention may be practiced otherwise than as specifically set forth in the appended claims.
