Background of the Invention

This invention relates generally to door hardware and more particularly to door locks capable of either- handed installation and having concealed screws on both inside and outside lock portions.

When selecting door locks, the handing of the door must be considered to avoid upside down or backward mounting of levers or inappropriate mounting of door knobs whose security is compromised by exposed mounting screws. The necessity for considering the myriad combinations possible between door locks of different designs and handing requirements imposed by architectural or occupancy requirements creates a significant cost burden due to inventory requirements, construction delays, and correction of errors in installation. These difficulties are well known to persons familiar with door hardware installation during construction or remodelling.

The foregoing illustrates limitations known to exist in present devices and methods. Thus, it is apparent that it would be advantageous to provide an alternative directed to overcoming one or more of the limitations set forth above. Accordingly, a suitable alternative is provided including features more fully disclosed hereinafter.

Summarv of the Invention

In one aspect of the present invention, this is accomplished by providing a door lock having concealed screws on both inside and outside members, and including an outside chassis having means for engaging an outside handle assembly and a bolt drawbar cam; an inside chassis having means for engaging an inside handle assembly and a bolt drawbar cam and having means for attaching inside and outside handle assemblies with the concealed screws; and two interchangeable handle assemblies for attaching to the inside chassis.

The foregoing and other aspects will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawing figures.

Brief Description of the Drawings

Figure 1 is an exploded partially sectional elevation view of a door lock mounting mechanism according to the present invention.

Detailed Description

In discussing the present invention, the terms handle assembly, knob assembly, and lever assembly, when used, are interchangeable. They are used in their generic form to refer only to the portion of a door lock which is grasped with the hand to operate the latch mechanism.

Figure 1 is an exploded partially sectional elevation view of a door lock mounting device according to the present invention. The lock, or latch bolt assembly, is not illustrated since it is not part of the present invention, but it may be any of a commonly available array of such latch bolt mechanisms. Otherwise, the lock of the present invention includes two identical handle assemblies 10 consisting of knobs 15 which are rotatably captured in bushing 20. The

method of capture, an "E" ring or other commonly used retaining device, is not illustrated. Bushing 20 is internally threaded and is itself rotatably captured in trim ring 100 by a retaining ring, a formed flare, or other means used for such rotatable retention applications. Trim ring 100 is equipped with two or more internally threaded hollow posts projecting into a door cavity. Bushing 20 has provisions, not illustrated, for application of torque to thread bushing 20 onto stud 170 of inside chassis 150, as appropriate. It is clear that handle assemblies 10 are functionally identical and, so long as knobs 15 are symmetrical, are interchangeable completely. In the case of levers or other asymmetric handles, actual interchangeability may be limited, although functional interchangeability still applies. It should be noted that handles 15 are equipped with bores 18, or spindle sockets, having longitudinal teeth, corners, or grooves for engaging mating longitudinal features of spindles. Outer chassis 50 and inner chassis 150 have several features in common and several slightly different features. The body of chassis 50 has two or more holes to accommodate internally threaded posts 30 of handle assemblies 10. Sleeve 70 projects outwardly from the chassis body and supports outer spindle 85 which has longitudinal features designed to mesh with previously described spindle bores 18 of handle assemblies 10. Outer spindle 85 has an externally cylindrical portion having a bore 82 in which inner spindle 80 is captured in a driven arrangement. Inner spindle 80 and bore 82 have longitudinal meshing features which constrain inner spindle 80 and outer spindle 85 to turn together. Biasing means 83 are also included within bore 82 of outer spindle 85 to force inner spindle 80 to an extended position. Inner spindle 80 is captured within bore 82 by staking or other common means which is not illustrated.

Inside chassis 150 is substantially identical to outside chassis 50 with a few important exceptions. Mounting legs 130 are spaced to mate with internally threaded posts 30 of knob assemblies 10. When inserted in the door cavity and aligned with outside chassis 50, mounting legs 130 register with internally threaded posts 30 such that posts 30 fit smoothly within alignment bores 165 in mounting legs 30. Mounting screws 160 are inserted from the inside surface of inside chassis 150 through mounting legs 130 into engagement with the threads of internally threaded posts 30, and when securely tightened, hold inside chassis 150, outside chassis 50, and knob assembly 10 in securely fixed relationship with each other. Posts 30 extend through holes in outside chassis 50 into alignment bores 165 in a telescopic arrangement which permits adjustment for doors of varying thicknesses. Mounting legs 130 also have recesses 168 behind the heads of mounting screws 160. These recesses accommodate internally threaded posts 30 of knob assembly 10 when the knob assembly is mounted on the inside of the door. Spindles 180 and 185 have the same relationship by means of spindle bore 182 and spindle bias 83 as has been described for the spindle couple of outside chassis 50. Stud 170 supports spindle 185 in its bore while the external threads provide connection capability with bushing 20 of handle assembly 10. This connection capability is a key feature of the present invention in that it permits attachment of either of the functionally identical handle assemblies 10 to inside chassis 150, and, by simply reversing the positions of inside chassis 150 and outside chassis 50, the handing of the door can be changed, or accommodated. Note that sleeve 70 of outside chassis 50 has no external threads, and, therefore, will not engage the internal threads of bushing 20. Thus, after installation, the outside handle assembly 10 presents

no access to either mounting screws 160 or to mounting stud 170. Note also that internally threaded posts 30 of inside handle assembly 10 telescope smoothly into recesses 168 of mounting legs 130 when the handle assembly is finally attached to inside chassis 150 by means of stud 170.

The door lock is pictured with two mounting posts and two mounting legs but may, of course, be provided with three or more legs. Size, weight, and strength requirements of the installation will ultimately determine the number of mounting legs required.