US2993720A

US2993720A - Resilient knob face retainer

Info

Publication number: US2993720A
Application number: US768218A
Authority: US
Inventors: Fred J Russell
Original assignee: Individual
Current assignee: Individual
Priority date: 1958-10-20
Filing date: 1958-10-20
Publication date: 1961-07-25
Anticipated expiration: 1978-07-25

Description

July 25, 1961 F. J. RUSSELL RESILIENT KNOB FACE RETAINER Filed Oct. 20, 1958 IN V EN TOR.

States This invention relates generally to spring retained coupling means and more particularly to a spring retainer provided with a cam and cam guide for locking a knob face into the frontal opening on a doorknob.

Most doorknobs are made either with the knob substantially solid, or of a hollow stamped knob with no frontal opening. The present invention is concerned with a new and effective assembly means particularly suited to permanent and positive attachment of the knob face to the hollow knob without the need to form a knob face flange to retain same in the frontal opening of a doorknob.

The invention involves the employment of a spring operated retainer means which can be compressed into a retracted position for purposes of assembly, but which springs back into a retaining position once the knob face has been fully inserted in its assembled position. Although spring retainer means have ben known in the past, all of them have been unsuitable for assembly of v knob faces to doorknobs under the conditions with which thepresent invention is concerned.

Ordinarily, a doorknob has an expensively finished surface which it is important not to mar by means of assembly tools of any kind. There has. been experience. with a number of spring retainer means which required the use of compressor pliers and other tools for the purpose of assembly, with resultant risk of scratching or denting the surface finishing of the knob or the knob face. Also, compressing such springs with various tools is both diflicult and time consuming.

It is a major object of the present invention to provide a spring retained knob and knob face assembly which can be constructed with only one part in addition to the knob and knob face.

It is an important object of the invention to provide a spring retained knob face which can be assembled without the use of any tools and without the risk of marring the surface finishing of the knob or knob face.

Another important object of the invention is to provide a spring retained knob face which, after assembly, is held so firmly that it will not loosen or rattle after installation and use.

Finally, it is an important object of the present invention to provide a spring retainer means which can be made so that it is completely invisible from the exterior of the knob, after assembly.

The foregoing and other objects of the invention are accomplished by means. of a spring retainer which fits inside a hollow insertion portion of the knob face, and urges outwardly a cam surface which engages the edge of the front opening of the hollow knob during insertion, and then snaps into a gripping position when insertion has been completed.

The novel construction of the invention may be understood from the following description of one specific embodiment, taken in connection with the accompanying drawings, in which:

FIGURE 1 is a front elevation view of a knob and a knob face assembly;

FIGURE 2 is a side elevational view of the knob and knob face of FIGURE 1, but partially broken away to reveal parts of the knob and knob face in a longitudinal sectional plane as indicated in FIGURE 1 by the arrows mm o which is in the form of a tubular and cylindrical section FIGURE 3 is an enlarged view of the interior of the knob face as viewed in the direction of the arrows 3-3 in FIGURE 2;

FIGURE 4 is an elevational View of the knob face as seen in FIGURE 3, but seen prior to insertion in the hollow knob, so that the spring retainer means is shown in an extended position; and

FIGURE 5 is a fragmentary perspective view of the edge of the insertion portion of the knob face and the cam portion of the spring retainer means.

In FIGURE 1, the visible parts of a doorknob indi cated generally by the arrow 10 are seen to be the hol' low knob 11 and the knob face 12, which latter is illustrated with a central opening 13 for the reception of locking means, if desired.

FIGURE 2 reveals the interior of the knob 11 sulficiently to show the third part of the assembly, the spring retainer 14, in its assembled position. FIGURE 2 also reveals the so-called knob face 12 is actually cup-shaped in construction and has a hollow insertion portion 15 snugly received in the frontal opening 16 of the hollow knob 11.

The knob face 12 is provided with an annular shoulder 17 which contacts the outer edge 18 of the frontal opening 16 around its entire periphery, being held snugly in position against the, edge 18 by the action of the spring'retainer 14 as will be described hereinafter.

The preferred form of spring retainer 14, illustrated in FIGURES 2 and 3 is a semi-cylindrical leaf spring 20 of U-shape which fits fairly closely inside of the tubular insertion portion 18 and extends about around that interior to present at the opposite ends of the spring 20 a pair of

guide members

21 and 22 which project radially outward through slots 23 and 24 (see FIGURE 5) to snugly contact the interior surface of the knob 11 at points 25 and 26 as seen in the longitudinal section of FIGURE 2. V v

The upper guide member 21 is provided with a folded extension which provides a cam 27, having a cam surface 28 which engages and slides on the edge 18 of the frontal opening during the process of insertion, and then snaps out to hold the knob face 12 in permanent position as illustrated in FIGURES 1 to 3.

Prior to assembly of the knob face 12 to the knob 11, the subassembly of the spring retainer 14 Within the insertion portion 18 of the knob face 12 has the appearance of the illustration in FIGURE 4, which reveals that the spring 20 is in an only partlycompressed condition, and the

guide members

21 and 22 assume a radially projecting position prior to final assembly.

The fragmentary perspective view of FIGURE 5 reveals that the guide member 21 and cam 27 are shaped to 'slide radially into the slot 23 which is seen to have a T-shaped cross section.

It will be understood that the slot is T-shaped in the specific embodiment only as a preferred feature. The shape or fit of the slot is not critical. It is necessary, however, that the cam receiving slot 23 have retainer shoulders23a and 23b for engaging the sides 21a and 21b of the guide member, thus permitting radial movement of the guide member 21 and its associated cam 27 during insertion, while serving to hold the cam 27 firmly against the point 25 on the interior surface of the knob 11 after assembly. Also, it will be appreciated that the slot 24 for guide member 22 need not be T shaped since that member carries no cam. Slot 24 is illustrated as T-shaped merely because it is simplest in manufacture to make

slots

23 and 24 of identical cross section.

In'assembly, the retainer 14 is compressed (to an even 3 greater extent than illustrated in FIGURE 3) so that the outermost points of

guide members

21 and 22, and cam 27, can be slipped within the insertion portion 18 and allowed to expand outwardly through

slots

23 and 24, respectively. Following said subassembly, the assembly illustrated in FIGURE 4 can be pressed into the circular front opening 16 in the knob 11. The knob face 12 is tilted with respect to the opening 16 and the lower guide member 22 is inserted in slot 24. Using guide member 2-2; as a pivot, the knob face 12 is then swung toward closure. During this part of the insertion operation, the face 28 of the cam 27 engages and slides on the edge 18' of the opening 16, causing the spring retainer 14 to permit full insertion of the knob face.

A preferred form of construction for the guide member 21, cam 27 and slot 23 is illustrated in the FIGURES 2 to 5, and best described in detail in connection with FIGURE 5. It is seen that the spring section 20 of the spring retainer 14 is provided at its end with an extension portion 30 which extends axially inward with respect to the knob 10. The inwardly extending portion 30 has a radially outwardly extending flange part to form guide member 21, and an extension of guide member 21 in turn forms cam 27. Preferably, the end of cam 27 is received in a notch 31 to give it structural rigidity relative to the rest of the spring retainer 14.

Preferably the guide member 21 is notched on each side of the cam 27 at notches 32 and 33 so that the engaging edges 21a and 21b are like spring fingers as best seen in the enlarged perspective view of FIGURE 5. Thus, these fingers yield resiliently to permit insertions and resiliently press the inner surface of the knob 11 at 25. The engaging edges 21a and 21b may even be bent, during the forming of the spring retainer 14 to best engage the surface 25. For example, they may be bent in the direction of the shoulder 17 on the knob face 12 so as to provide a pinching or gripping action.

It is a preferred species of the invention that the interior surfaces 25 and 26, at which the edges of the guide members make contact after asembly, are concave surfaces so that a resilient holding force axial to the knob 11 is provided; however, it will be understood that such an axial force might be provided in other ways, for instance, by shaping of the

resilient guide members

21 and 22, and the cam surface 28.

It should also be recognized that the scope of the invention includes a double cam structure, i.e. one in which the lower end of spring retainer 14 is shaped exactly like the upper end, complete with a cam member .like 27, and is received in a slot like slot 23, exactly as already described in connection with FIGURE 5.

While I have described in detail a specific embodiment of my invention, it is not my intention to limit the scope of the invention to the particular embodiment described.

.It will be obvious to those skilled in the art that various changes in the insert member and the receiving member (in this case the knob face and hollow knob, respectively), or in the shape of the cam slot, cam, or spring means are possible without departing from the spirit and scope of the invention, which is to be limited solely by the following claims.

I claim:

1. A coupling means which includes: a knob body lmember having edge portions forming a receiving opening; a knob face member having an insertion portion receivable in said receiving opening and having a cam slot therein, said knob face member having an outer shoulder means engaging the outer peripheral surface of said receiving opening; a spring retainer means; and a cam member incorporated with said spring retainer means, said means being subject to radially outward expansion whereby to urge said cam member outwardly through said cam slot into engagement with the inner surface of said body member, said cam member having a portion in engagement during assembly with an edge portion of 4 the body member forming said receiving opening and adapted to compress said spring retainer means dunng msertion, said cam member having an extended position wherein a portion of the body member adjacent said edge portion is gripped between said cam member and said outer shoulder means.

2. In a knob assembly, the combination of: a hollow knob body having a circular receiving opening and a concave inner surface at the peripheral wall of said opening; a cover plate for said opening, said cover plate having a tubular extension closely received in said opening, and an annular shoulder adapted to mate closely with the outer peripheral surface of said opening; walls defining a pair of retainer slots in said tubular extension at opposite points thereof, each of said retainer slots being spaced from said annular shoulder by a distance corresponding to the thickness of the peripheral wall of said receiving opening, and each being provided with an axially disposed cam slot communicating with said retainer slot but having relatively less width transverse to the axis of said tubular extension; a spring retainer comprised of an elongate leaf spring located within said tubular extension and extending from one retainer slot to the other throughout a portion of the interior circumference of said tubular extension; said spring retainer having a pair of retainer members respectively at opposite ends thereof, one of said retainer members being in mating relationship with each respective cam slot and held by the spring action of said spring retainer in a position projecting outwardly through the respective cam slot; each of said retainer members being radially movable in said retainer slot into engagement with said knob body.

3. In a knob assembly, the combination of: a hollow knob body having a circular receiving opening and concave inner surfaces at the peripheral wall of said opening; a cover plate for said opening, said cover plate having a tubular extension closely received in said opening, and an annular shoulder adapted to mate closely with the outer peripheral surface of said opening; walls defining a pair of retainer slots in said tubular extension at opposite points thereof, each of said retainer slots being spaced from said annular shoulder by a distance corresponding to the thickness of the peripheral wall of said receiving opening, and each being provided with an axially disposed cam slot communicating with said retainer slot but having a width less than the length of said respective retainer slot and each providing a retaining shoulder spaced from said annular shoulder; a spring retainer comprised of an arcuate leaf spring within said tubular extension and extending around the interior circumference of said extension from one retainer slot to the other; said spring retainer having retainer members on opposite ends thereof, at least one of said retainer members having a cam mating in cross section with said respective cam slot and held by the spring action of said spring retainer in a position projecting outwardly through said respective slot.

4. A knob assembly comprising a knob body having a receiving opening and-a concave inner surface adjacent said opening, a cover plate for the opening having an annular wall closely received in said opening and said cover plate having a space within said wall, an annular shoulder on said plate mating closely with the outer surface of the knob at the periphery of said opening, said annular wall having retainer slots in opposite sides of the wall and a cam slot connected to one of said retainer slots, and a leaf spring in said space extending around the wall from one retainer slot to the other, said leaf spring having retainers on opposite ends thereof, each retainer extending by pressure of the leaf spring through the respective retainer slot and having each a position of engagement respectively with the concave inner surface of the knob body and a wall of the retainer slot, whereby to provide a grip upon the knob body between the annular shoulder and the retainers, and a cam portion on one of said retainers moveable in said cam slot whereby to eifect a yielding of the respective retainer When said wall is pushed into retained position in said receiving opening.

References Cited in the file of this patent UNITED STATES PATENTS Schoepe et al. Nov. 22, 1949