Information
-
Patent Grant
-
6231092
-
Patent Number
6,231,092
-
Date Filed
Thursday, October 2, 199727 years ago
-
Date Issued
Tuesday, May 15, 200123 years ago
-
Inventors
-
Original Assignees
-
Examiners
Agents
- Sughrue, Mion, Zinn, Macpeak & Seas, PLLC
-
CPC
-
US Classifications
Field of Search
US
- 292 347
- 292 348
- 292 349
- 292 355
-
International Classifications
-
Abstract
A porcelain knob construction comprising a metal mounting member which is adhered to a porcelain knob (101) comprising a body with a shaft (105) protruding therefrom. The shaft is hollow and has a blind hole (104) formed in the free end thereof. The mounting member includes an annular recess (108) to receive the free end of the shaft (105). The mounting member and shaft (105) are adhered only adjacent the shaft free end whereby the interior of the blind hole (104) is substantially free of adhesive.
Description
FIELD OF THE INVENTION
The present invention relates to knobs and, in particular, to porcelain knobs for use with either cupboards or doors.
BACKGROUND OF THE INVENTION
Porcelain knobs have long found favour because of their appearance and find use either as fixed knobs for cupboards or as rotating knobs for doors. The porcelain knob itself has a bulbous body which is shaped to be conveniently grasped and a shaft protrudes from the body. The shaft is hollow having a blind hole formed in its free end and a metal mounting member is secured by adhesive to the shaft. The adhesive has substantially filled the shaft hitherto.
Such a conventional knob construction suffers from the disadvantage that in the event that there is an excessive load applied to the knob, the knob is liable to fracture in the region where the knob shaft joins the bulbous body. This is undesirable for various reasons, including that in the customer's mind, a precise component should not fail and that the end result is very unsightly.
It is the object of the present invention to provide an improved porcelain knob construction in which the mechanism of failure, if any, is improved.
DISCLOSURE OF THE INVENTION
In accordance with the present invention there is disclosed a porcelain knob construction comprising a metal mounting member which is adhered to a porcelain knob comprising a body with a shaft protruding therefrom, said shaft being hollow and having a blind hole formed in the free end thereof, wherein said mounting member includes an annular recess to receive said free end of said shaft and wherein said mounting member and shaft are adhered only adjacent said shaft free end whereby the interior of said blind hole is substantially free of adhesive.
BRIEF DESCRIPTION OF THE DRAWINGS
Two embodiments of the present invention will now be described with reference to the drawings in which:
FIG. 1
an exploded perspective view showing the prior art arrangements for fixed cupboard knobs and rotating door knobs, respectively;
FIG. 2
is a cross-sectional view through a prior art cupboard knob prior to failure;
FIG. 3
is a view similar to
FIG. 2
, but showing the result after failure;
FIG. 4
is an exploded perspective view of a cupboard knob in accordance with the first embodiment of the present invention;
FIG. 5
is a cross-sectional view similar to
FIG. 2
, but showing the cupboard knob of
FIG. 4
;
FIG. 6
exploded perspective view similar to that of
FIG. 4
, but illustrating the door knob of the second embodiment; and
FIG. 7
is a cross-sectional view similar to
FIG. 5
, but illustrating the door knob of FIG.
6
.
PREFERRED EMBODIMENTS OF THIS INVENTION
As seen in
FIG. 1
, a cupboard knob
1
and a door knob
11
of conventional construction are illustrated together with their associated mounting hardware. For the cupboard knob
1
, the mounting member takes the form of an internally threaded sleeve
2
which has a flange
3
at one end and which is adhered by means of epoxy adhesive, or similar, into the hollow interior
4
of a shaft
5
formed on the knob
1
. A threaded fastener
6
which mates with the sleeve
2
completes the mounting hardware.
The arrangements of the door knob
11
are essentially similar in that the knob itself is provided with a shaft
15
having a hollow interior
14
which again forms a blind hole. The door latching mechanism is provided with a square spindle
16
which is received in a corresponding square cavity
17
in a sleeve
12
. The sleeve
12
has a flat annular flange
19
from which protrudes a shank
20
which is glued into the hollow interior
14
.
FIGS. 2 and 3
illustrate the prior art arrangement for the cupboard knob
1
, however, it will be apparent to those skilled in the art that the arrangements for the prior art door knob
11
are essentially equivalent. The sleeve
2
is glued to the hollow interior
4
and the entire space between the sleeve
2
and the interior of the shaft
5
is filled with adhesive
24
. This securely binds the sleeve
2
to the knob
1
and enables the threaded fastener
6
to be passed through the cupboard door
25
and mate with the sleeve
2
. In the event of a failure, the cupboard knob
1
breaks approximately along the line A—A of
FIG. 2
to create the situation illustrated in FIG.
3
.
It is thought that a contributing factor towards this mode of failure is that the adhesive
24
contributes to a strengthening of the shaft
5
. As a consequence, the line of fracture is located approximately in the position of the line A—A of FIG.
2
.
Turning now to
FIG. 4
, in the embodiments of the present invention to be described, the same numbering scheme will be used as in the numbering of the prior art equivalent components, save that the number will be increased by 100. Thus,
FIG. 4
illustrates in exploded view the cupboard knob
101
of the preferred embodiment which has a shaft
105
and hollow interior
104
forming a blind hole, essentially as before. The previous flange
3
has been expanded to form a flange
103
and the previous sleeve
2
has been shortened into an internally threaded boss
102
. A peripheral lip
107
on the knob side of the flange
103
forms an annular recess
108
which snugly receives the free end of the shaft
105
.
In the preferrred form shown, the boss
102
extends into less than 25% of the depth of the hollow interior
104
.
The position following mounting of the knob
101
to the cupboard door
25
is illustrated in FIG.
5
. It will be seen that the threaded fastener
106
passes through the boss
102
. The hollow interior
104
is of sufficient depth to accommodate either different length fasteners
106
, or different thicknesses of the different cupboard doors
25
.
However, as seen in
FIG. 5
, the adhesive
124
used to glue the flange
103
and shaft
105
together, is only applied immediately adjacent the free end of the shaft
105
. Thus the hollow interior
104
is substantially free of adhesive
124
, except immediately adjacent the free end of the shaft
105
.
The boss
102
includes a series of raised protuberances
110
to improve the adhesion between the boss
102
and the shaft
105
.
Turning now to
FIGS. 6 and 7
, it will be seen that the door knob
111
is substantially as before with its hollow interior
114
and shaft
115
. The out-of-round (ie. square) spindle
116
is also as before.
However, whilst the sleeve
112
and cavity
117
are as before, the shank
120
is substantially shortened and the flange
119
is provided with a peripheral lip
107
which forms an annular recess
108
together with the shank
120
. The mounting of the door knob
111
on the door
26
is illustrated in
FIG. 7
from which it will be seen that adhesive
124
again is only positioned within the annular recess
108
and therefore only adheres to the free end of the shaft
115
. The hollow interior
114
, except adjacent the free end of the shaft
115
, is substantially free of adhesive
124
.
Experimental tests to date with the two above described embodiments indicate that failure of the knob construction only occurs at loads greater than those at which failure of the prior art arrangements occurred. Furthermore, in the event that failure does occur, one mode of failure is for the adhesive
24
,
124
to release its grip on the free end of the shaft
105
,
15
. Since the failure is not of a precise component, the purchaser or user tends to blame the adhesive rather than the manufacturer and may even attempt to re-glue the knob
101
or
111
back into the annular recess
108
. This attempt will generally be unsuccessful since the gluing procedures adopted by home handymen are generally insufficient for such loads. However, the purchaser or user under such circumstances is thought likely not to be deterred from re-purchasing a knob construction manufactured by the original manufacturer.
The foregoing describes only two embodiments of the present invention and modifications, obvious to those skilled in the art, can be made thereto without departing from the scope of the present invention. For example, the knob construction can be provided with a decorative washer or annular flange which surrounds the shaft
105
,
115
and is located between that shaft and the cupboard door
25
or door
26
.
Claims
- 1. A porcelain knob construction comprising a metal mounting member which is adhered by an adhesive to a porcelain knob comprising a body with a shaft protruding therefrom, said shaft being hollow and terminating in a free end and having a blind hole formed in said free end, wherein said mounting member includes an annular recess to receive said free end of said shaft at an overlapping region and wherein said mounting member and shaft are adhered by said adhesive only adjacent said free end at said overlapping region whereby the interior of said blind hole remote from said overlapping region is substantially free of adhesive.
- 2. A construction as claimed in claim 1 wherein said mounting member includes a boss protruding partially into said blind hole and adhered thereto.
- 3. A construction as claimed in claim 2 wherein said boss extends into less than 25% of the depth of said blind hole.
- 4. A construction as claimed in claim 2 wherein said mounting member includes a peripheral lip around said boss, the outer surface of said shaft free end being snugly received within an inner edge of said lip.
- 5. A construction as claimed in claim 2 wherein said boss includes at least one outwardly facing gripping protuberances to improve adhesion between said boss and said blind hole.
- 6. A construction as claimed in claim 1 wherein said mounting member includes an internally threaded bore extending through said boss.
- 7. A cupboard door knob assembly comprising the porcelain door knob construction as claimed in claim 1 and a threaded fastener to fasten said door knob construction to a cupboard door.
- 8. A construction as claimed in claim 2 wherein the mounting member includes a sleeve extending away from said boss, said sleeve having an out-of-round blind hole to engage a spindle of corresponding cross-section.
- 9. A construction as claimed in claim 8 wherein said sleeve blind hole is of substantially square cross-section blind hole and said spindle is of substantially square cross-section.
Priority Claims (1)
Number |
Date |
Country |
Kind |
03195 |
Oct 1996 |
AU |
|
US Referenced Citations (13)
Foreign Referenced Citations (2)
Number |
Date |
Country |
406014 |
Feb 1934 |
GB |
2203641 |
Oct 1988 |
GB |