Abstract:
A trim attachment and method comprises a door lever/knob which is assembled to a spindle housing of a lock assembly by sliding the door lever/knob over the spindle. A retaining mechanism within the door lever/knob automatically engages the spindle to couple the door lever/knob to the spindle when the door lever/knob is properly positioned on the spindle. The spindle and door lever/knob have mating exterior and interior ribs providing torque transfer between the spindle and door lever/knob. An aperture is provided in the door lever/knob to depress a portion of the retaining mechanism to release the retaining mechanism, allowing the door lever/knob to be removed. The improved knob/lever trim attachment and methods provide an easily assembled and manufactured, aesthetically pleasing, and easily replaceable assembly for a door lock assembly.

Description:
This application claims the benefit of U.S. Provisional Application No. 60/177,000 filed Jan. 19, 2000, herein incorporated by reference. 
    
    
     TECHNICAL FIELD 
     This invention relates generally to door knob/lever assemblies, and more particularly to improved knob/lever trim attachment and methods to provide an easily assembled and manufactured, aesthetically pleasing, and easily replaceable assembly. 
     BACKGROUND OF THE INVENTION 
     In the art of door handle knob/lever assemblies, a hollow shaft is rotatably mounted within a door preparation in the well-known fashion by a housing attached to the door by screw fasteners. A door handle, and typically, a doorknob or lever, is mounted on the shaft by any of several mounting techniques. One or more set screws are used to secure the doorknob to the shaft. Problems with this technique include that the screw head is typically visible creating an aesthetically unpleasing surface. Special tools, such as an Allen wrench, may also be required to install and remove the doorknob. During operational life of the knob the screw can become loose, thus resulting in wobble, preventing proper operation of the door handle, or causing the handle to fall off when grasped by the user. 
     Another mechanical mounting technique stakes material in the reduced neck of the knob into openings formed in the shaft. This also axially locks the doorknob to the shaft while enabling the shaft to rotate when rotating the doorknob. However, this method is more of a permanent attachment technique and generally requires special knowledge and tools for removal. 
     In another mounting technique, the doorknob has a cylindrical, reduced neck portion which is slidably received over the shaft. The shaft has a radially projecting pin which is spring biased outwardly beyond the outer surface of the shaft. The pin is retracted by pressing it inwardly. The shaft receives the cylindrical portion of the door knob thereover, the cylindrical portion having an aperture formed therein which is sized to receive the pin of the shaft therethrough. The arrangement is such that by pressing the pin inwardly to its retracted position, sliding the cylindrical portion of the door knob over the pin, and aligning the aperture with the pin, the pin can extend through the aperture for axially and rotatably locking the door knob to the shaft. The pin method, however, generally requires that the complete handle assembly be disassembled in order to retract the pin and remove the knob. In addition, the pin method provides a relatively poor bearing support which generally allows a certain amount of rotational play and can also result in wobble. 
     Once secured to the shaft, the doorknob and shaft are rotatably mounted within an opening formed in the housing. In typical door assembly constructions there is a certain amount of wobble between the doorknob and shaft and the housing. This wobble is attributable to tolerances between the shaft and the opening of the housing, and the axial space between the housing and the doorknob. 
     From the foregoing, the limitations of known trim attachment methods include possible accidental or eventual pull of the trim (lever/knob) by the user which could cause injury. Any wobble or looseness of the trim also suggests inferior quality. Further, if replacement of the trim is desired, the user is faced with a difficult task requiring special knowledge of the construction, or the user must have special tools therefore. Typical trim attachments also degrade from the appearance of the trim or require removal of the lock from the door. Other disadvantages are also apparent in known attachment methods and trim assemblies. 
     The foregoing illustrates limitations known to exist in present handle/door knob designs. 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. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide an improved knob/lever trim attachment and method to allow easy assembly and manufacture, and to provide an aesthetically pleasing, and easily replaceable trim assembly. It is a further object of the present invention to provide an improved knob/lever trim attachment and method which prevents wobble between the knob/lever trim and the doorknob shaft, as well as improving resistance to torque upon rotation thereof. 
     In one aspect of the present invention, this is accomplished by providing a door handle/knob assembly comprising a spindle housing having a first end and a second end, wherein the first end comprises a spindle and the second end comprises a mechanism for engagement to a door lock assembly. The door lever/knob assembly further comprises a door knob having a handle portion and a neck portion, wherein the neck portion comprises a recess and a housing for a mechanism to retain the door knob on the spindle, and a mechanism for preventing relative rotation of the handle portion in relation to the spindle portion. In another aspect of the present invention, there is provided a method of attaching a door lever/knob to a door lock assembly comprising the steps of aligning a recess of the neck portion of the door lever/knob with a spindle portion of the door lock assembly, sliding the recess over the spindle portion, and automatically engaging a mechanism for retaining the door knob on the spindle. A method or detaching a door lever/knob from a door lock assembly is also provided. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an exploded perspective view of the door handle knob/lever trim assembly of the present invention showing the knob/lever trim in a cross-section to reveal the interior recess and associated parts thereof; 
     FIG. 2A is a cross-sectional view of the door handle knob/lever trim in accordance with the present invention of FIG. 1; 
     FIG. 2B is a cross-sectional view of the door handle knob/lever trim in an alternate embodiment of the present invention; and 
     FIG. 3 is an exploded perspective view of an alternate embodiment of the door handle knob/lever trim assembly of the present invention showing the knob/lever trim in a cross-section to reveal the interior recess and associated parts thereof. 
    
    
     DETAILED DESCRIPTION 
     Referring now to the drawings, wherein similar reference characters designate corresponding parts throughout the several views, there is generally indicated at  10  a door knob/lever trim assembly of the present invention. As shown in FIG. 1, the door knob/lever trim assembly  10  comprises a knob/lever trim  12  of the type generally used as a door handle. Other styles of knob/lever trim  12  may be provided if desired, generally comprising a knob or lever which is grasped by the user and rotated for operation of the door latch mechanism. A retainer clip  30  is provided in association with the trim  12 , and a spindle housing  40  which is part of a lock chassis (not shown) is attached to trim  12 . The knob/lever trim  12  comprises a handle portion  14  shown herein as a standard doorknob, which narrows down into a neck portion  16 . The neck portion  16  of the knob/lever trim  12  includes a first recess  18  formed in a bottom surface  20  of the neck portion. The first recess  18  is formed generally coaxial to the longitudinal axis A of the neck portion  16 . At least one slot, or internal rib  21  is formed into the surface of the first recess  18  such that it is parallel to longitudinal axis A. A second recess  26 , is also formed coaxial to the longitudinal axis A and having a larger diameter than the first recess  18 . As best shown in FIG. 2A, the second recess  26 , has a shallower depth than that of the first recess  18  such that a ledge is formed between the diameter of the second recess  26  and the diameter of the first recess  18  at the bottom of the second recess  26 . A slot  22  is then formed by inserting a washer-shaped insert  28  into the second recess  26 . The washer shaped insert  28  has an interior diameter corresponding to the diameter of the first recess  18 . The outer diameter of the washer shaped insert  28  generally corresponds to the diameter of the second recess  26 . The slot  22  is formed by ensuring that a gap exists between the insert  28  and the ledge formed at the bottom of the second recess  26 . The insert  28  is secured to the second recess  26  by an interference fit, welded into place, or any other appropriate fastening mechanism. The insert  28  also includes at least one slot, or interior rib  21 ′ generally corresponding to the at least one interior rib  21  on the surface of the first recess  18 . In a preferred form, a plurality of ribs  21 ,  21 ′ are provided for orientation and additional strength in the assembly as will be seen. The insert  28  is secured to the second recess  26  while ensuring that the interior ribs  21  and  21 ′ are properly aligned. Using insert  28 , the retaining clip  30  is inserted against the ledge formed at the bottom of the second recess  26  and then constrained in location within a plane normal to axis A within the slot  22  created by the addition of insert  28  as will be described in greater detail below. 
     An alternate embodiment is shown in FIG. 2B, wherein the first recess  18  includes a slot  22  formed generally radially perpendicular to the longitudinal axis A along an interior surface  24  of the recess  18 . The slot  22  is machined into the interior diameter surface of the first recess  18 . This embodiment requires that retainer clip  30  is able to be deformed for passage through the first recess  18  and then inserted into the slot  22 . 
     The retainer clip  30  is housed within the slot  22 . The retainer clip  30  is generally formed as a retaining ring or snap ring, and has a thickness generally corresponding to the width of the slot  22  such that there is no play, preventing axial movement of the retainer clip  30  within the slot  22 . This will provide a more secure fastening of the door handle knob/lever trim  12  on the spindle housing  20 . The retainer clip  30  is accessible through a clip access slot  24 , which is an aperture through the wall of the neck  16 . By depression of the retainer clip end  32 , the retainer clip  30  is at least partially expand radially within the slot  22 . 
     Spindle housing  40  comprises a first end  42  and a second end  44 . The first end  42  is a spindle having a generally cylindrical body. The second end  44  comprises a door lock assembly engagement portion. The spindle  42  has a leading end  46  which comprises a chamfer or radius. The spindle  42  also has at least one external rib  47  on the surface thereof matingly corresponding to the at least one internal rib  21  of the door handle/knob trim  12  and at least one internal rib  21 ′ provided on insert  28 . 
     The retainer clip  30  has an outside diameter which is slightly smaller than the diameter of the slot  22 . This allows the retainer clip  30  to expand when engaged by the leading end  46  of the spindle  42  as will be discussed in detail below. 
     The method of attaching the door handle/knob trim  12  to the spindle housing  40  to form a door lock assembly  10 , first requires that the first recess  18  is aligned with the spindle portion  42  of the spindle housing  40  such that the internal ribs  21 ,  21 ′, in the knob/lever trim  12  are aligned with the external ribs  47  on the spindle. The door handle/knob trim  12  is moved such that the recess  18  slides over the spindle portion  42 . The internal ribs  21 ,  21 ′ in the knob lever trim  12  matingly engage the external ribs  47  on the spindle  42 . As the leading edge  46  of the spindle  42  engages the retainer clip  30  housed in slot  22 , the radiused edge  46  of the spindle forces the retainer clip  30  to open and allow the door handle/knob trim  12  to continue to slide over the spindle portion until the retaining clip engages the spindle slot  48 . When the trim is properly installed, the retainer clip  30  will make an audible sound indicating the knob/lever trim  12  is securely locked in place. The spindle slot  48  allows a portion of the retainer clip  30  to engage the spindle  42 . This engagement prevents further axial movement both toward the spindle housing  40  and away from the spindle housing. The engagement of the external ribs  47  on the spindle  42  with the internal ribs  21 ,  21 ′ of the door handle/knob trim  12  prevents relative rotation between the spindle housing  40  and the door handle/knob trim  12 . The door handle/knob trim  12  is thus securely fastened to the spindle housing  40  in a manner preventing both axial and radial movement with respect to the spindle housing without wobble or play. 
     The method of detaching the door handle/knob from a door lock assembly comprising the steps of depressing retainer clip end  32  causing retainer clip  30  to expand and dislodge from the spindle slot  48 . The door handle/knob trim  12  may then be slid away from the spindle housing  40  until said door handle/knob trim is completely disengaged from the spindle  42 . Depressing retainer clip end  32  causes the retainer clip  30  to expand radially within slot  22  such that the retainer clip  30  disengages retainer slot  48  on the spindle  42 , thus allowing axial movement of the door handle/knob trim  12 . The removal is accomplished without the need of specialized tools or specialized knowledge. Accordingly, any wire form, such as a paper clip, nail, ball point pen, coat hangar end, or the like, can be inserted through clip access slot  24  in the door handle/knob trim  12  to depress the retaining clip end  32 . The retainer clip access slot  24  is preferably large enough to provide access to the retainer clip end  32  by any suitable wire form tool to cause disengagement of the retainer clip  30  from spindle slot  48 . Once the door handle/knob trim  12  is removed, a new door handle/knob trim can be attached to the spindle housing  40 . This is especially useful when redecorating a room, easily replacing the door handle/knob trim with one of a different color, finish, or ornamental design can quickly and easily enhance the aesthetic appearance of a door and/or room. 
     Referring now to FIG. 3, an alternate embodiment of the present invention is shown. Door knob/lever trim assembly  110  comprises a knob/lever trim  112 . A retainer clip  130  is provided in association with the trim  112 , and spindle housing  40  which is part of a lock chassis (not shown) is attached to trim  112 . In addition, a torque ring component  150  is provided to help transfer rotational forces between spindle  40  and trim  112  as well as hold retainer clip  130  in its proper axial position. The knob/lever trim  112  comprises a handle portion  114  shown herein as a standard doorknob, which narrows down into a neck portion  116 . The neck portion  116  of the knob/lever trim  112  includes a first recess  118  formed generally coaxial to the longitudinal axis A of the neck portion  116 . At least one slot, or internal rib  121  is formed into the surface of the first recess  118  such that it is parallel to longitudinal axis A similar to that of knob/lever trim  12  of the previous embodiment. A second recess section  126  positioned toward the end of neck portion  116  having varying diameters each having a larger diameter than the first recess  118 . 
     Retainer clip  130  is similar in operation to retainer clip  30  of the previous embodiment. The retainer clip  130  has an ovalized outside diameter which is slightly smaller than the diameter of the slot  22 . This allows the retainer clip  30  to expand when engaged by the leading end  46  of the spindle  40 . Retainer clip  130  engages slot  22  of spindle  40  in the same manner as discussed in the previous embodiment. Retainer clip  130  has two ends  132  opposite a disengagement portion  134  generally at the mid point between ends  132 . Disengagement portion  134  is positioned radially directly below an access aperture  136 . An object inserted into access aperture  136  depresses disengagement portion  134 , deforming retainer clip  130  and disengaging retainer clip  130  from slot  22  of spindle  40 . 
     Torque ring component  150  comprises a generally washer shaped body portion  152  having a central aperture  154  correspondingly shaped to matingly engage spindle  40  in a co-rotating manner. Torque ring component  150  also comprises an arm extension portion or tang  156  extending parallel to axis A and engaging an aperture (not shown) in the spindle  40 . Tang  156  provides additional strength and an additional torque transfer path for rotational forces between knob/lever trim  112  and spindle  40 . The washer shaped body portion  152  of torque ring component  150  may also include one or more small tabs  158  extending radially outward from an outside diameter of washer shaped body portion  152 . These small tabs  158  engage corresponding recesses (not shown) in neck portion  116  which also provides an additional torque transfer path for rotational forces between knob/lever trim  112  and spindle  40 . 
     The present invention provides a knob/lever trim attachment assembly which prevents accidental or eventual pull of the trim attachment from the spindle housing  40 . The installation and replacement of the trim  12  is greatly simplified, and does not require any special tooling or knowledge of the assembly construction. The attachment minimizes wobble or looseness by provision of a significant bearing surface therebetween, while allowing for a small shank diameter if desired for design aesthetics. The attachment provides an aesthetically pleasing construction which doesn&#39;t require screws, set screws or other unsightly attachment means, with the attachment being effectively concealed. The attachment is constructed such that the integrity of the knob/lever finish is not compromised, either during manufacture or installation/replacement. Manufacture of the attachment is simplified and cost effective, and installation is simplified by ensuring proper orientation between components. The strength and durability of the attachment is enhanced and the resistance to torque enhanced due to the cross section configuration of the spindle  40  and mating recess in the knob/lever shank  16 . 
     Although the present invention has been described above in detail, the same is by way of illustration and example only and is not to be taken as a limitation on the present invention. Accordingly, the scope and content of the present invention are to be defined only by the terms of the appended claims.