U.S. patent number 3,625,462 [Application Number 05/036,100] was granted by the patent office on 1971-12-07 for articles of furniture.
Invention is credited to W. Noel Jordan.
United States Patent |
3,625,462 |
Jordan |
December 7, 1971 |
ARTICLES OF FURNITURE
Abstract
The present invention relates to furniture joints and
ground-engaging i.e. foot, members of furniture associated with
such joints. There is provided a joint in an article of furniture
between two interengaging members, the joint having a first part
with an H cross section elongated element and a second part
including a pair of bosses spaced apart by a distance generally
equal to the width of the H central web. These joint parts are a
push fit together and are bonded by a heat-treated resin adhesive.
A ground-engaging member associated with one part of the joint is
so curved that in an unloaded state only the end regions of the
curve engage the ground whereas in a loaded state not only the end
regions but also at least some intermediate regions engage the
ground. There is also provided an improved method of making a part
of the joint disclosed.
Inventors: |
Jordan; W. Noel (Sheerness,
EN) |
Family
ID: |
27258603 |
Appl.
No.: |
05/036,100 |
Filed: |
May 11, 1970 |
Foreign Application Priority Data
|
|
|
|
|
May 29, 1969 [GB] |
|
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27,141/69 |
May 29, 1969 [GB] |
|
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27,142/69 |
Jun 25, 1969 [GB] |
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32,159/69 |
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Current U.S.
Class: |
248/188.8;
403/298; 403/189; D6/709 |
Current CPC
Class: |
A47B
91/04 (20130101); F16B 12/44 (20130101); Y10T
403/559 (20150115) |
Current International
Class: |
A47B
91/00 (20060101); A47B 91/04 (20060101); F16B
12/00 (20060101); F16B 12/44 (20060101); A47b
013/06 () |
Field of
Search: |
;248/188.8,165,158
;287/13R,54R,54A,54B,54C,56 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Foss; J. Franklin
Claims
I claim:
1. In an article of furniture, a joint between two interengaging
members, such as a ground-engaging member and a leg member, the
said joint comprising a first part and a second part, the said
first part including an elongated element of generally H cross
section with an elongated central web and two elongated flanges
terminating said web, and the said second part including a pair of
bosses spaced apart by a distance generally equal to the width of
the said central web thereby to define a slot therefor, the said
two joint parts being a push fit one with the other and being
retained in interengaging relation by bonding with a heat-treated
resin adhesive; and wherein the base of the said slot defined
between the two said bosses is raised above the level where the
said bosses originate and the said flanges terminate; and wherein
the said central web is machined short of its abutting member, i.e.
the base of the said slot defined between the two bosses, thereby
to provide a chamber for accumulated resin; and wherein a said
joint part is drilled to vent the said chamber to atmosphere.
2. A joint as defined in claim 1 wherein to avoid localization of
stresses load-bearing areas of the joint, other than the faces of
the said bosses facing inwards and closing on the said central web,
are radiused.
3. In an article of furniture, a joint as defined in claim 1 and at
least one ground-engaging member which is so curved that in an
unloaded state only the end regions of the said curve engage the
ground, whereas in a loaded state not only the said end regions but
also at least some intermediate regions engage the ground.
Description
Prior applications: In Great Britain
On May 29, 1969 and numbered 27141/69
On May 29, 1969 and numbered 27142/69
On June 25, 1969 and numbered 32159/69
The invention relates to improvements in articles of furniture and
more particularly to improvements in the construction of joints
between members thereof, e.g., between foot members thereof and leg
members thereof. The invention relates to a particular form of such
foot member and to a method of making a joint part.
There exist numerous proposals relating to methods and means for
attaching generally vertical or upright leg members to generally
horizontal foot members but the majority of such proposals involve
the use of screws or rivets. The former have the disadvantage that
they may easily become loosened in use and the latter have the
disadvantage that, even with extensive finishing, their presence is
apparent.
It is thus an object of the present invention to provide an article
of furniture comprising at least one joint between two members,
such as a leg member and a foot member, which joint does not rely
for its strength on screws or rivets, is attractive or unobtrusive
to the eye and is mechanically secure.
It is a further object of the invention to provide an improved
method of machining a part of such a joint.
Furthermore, it is known that most chairs and the like suffer from
the disadvantage that when they are loaded i.e. sat on, the sitter
often experiences a degree of shock e.g. in the region of his
spine.
It is thus a still further object of the present invention to
provide an article of furniture which, although mechanically sound
and not unduly springy, exhibits sufficient inherent "give" to
ensure that such loading shocks are at least substantially
obviated.
In accordance with these and other object there is provided in an
article of furniture, a joint between two interengaging members
e.g. a foot member and a leg member, which joint comprises a first
part, either constituting or associated with one said member,
including an elongated element, e.g. extruded of generally H cross
section with an elongated central web and two elongated flanges
terminating said web, the joint further comprising a second part,
either constituting or being associated with the other said member,
including a pair of bosses spaced apart by a distance generally
equal to the width of the said central web thereby to define a slot
therefor, two joint parts being a push fit one with the other and
being retained in interengaging relation by bonding with a
heat-treated resin adhesive.
Advantageously, at least some of the load-bearing areas of the
joint are radiused thereby to ensure that stresses, e.g. resulting
from dropping of the article of furniture, are not confined to a
single point of a sharp angle but instead to a radiused change of
direction, i.e. are not localized.
In accordance with a preferred embodiment of the invention, all the
load bearing areas are radiused with the exception of the faces of
the bosses facing inwards and closing on the said central web.
Preferably, the externally directed faces of the flanges are
radiused and the regions of the other joint part with which they
abut are similarly radiused.
Advantageously, the base of the slot between the two bosses is
raised above the level where at the said bosses originate and the
flanges terminate. Similarly, it is advantageous for the central
web to be machined short of its abutting member, i.e. the base of
the slot, thereby to ease problems of manufacturing tolerance and
provide a chamber for resin accumulated during the bonding
process.
In such a case, it is a further preferred feature of the invention
to provide a drilling to vent the chamber to atmosphere thereby to
ensure that resin trapped therein will not force the parts of the
joint apart as a result of expansion during heat treatment.
Also in accordance with the present invention there is provided an
improved method of machining a part of the said joint which method
involves the utilization of a pair of parallel rotary cutters with
bevelled edges, which cutters machine the side faces (i.e. those
interrupted by the slot) of the second part of the joint (as
defined above) in true parallelism in all planes and bevel the
lower edges of the said faces to avoid localization of
stresses.
Advantageously bevelling of various other regions of the previously
proposed joint is effected, also for the purposes of avoiding
localization of stresses.
Also in accordance with the present invention there is provided in
association with such a joint at least one ground-engaging member
which is so curved that in an unloaded state only the end regions
of the curve engage the ground whereas in a loaded state not only
the end regions but also at least some intermediate regions engage
the ground. It will be evident that the change of conditions (on
loading) from limited to greater engagement provides the
aforementioned degree of "give" and that in this way the article of
furniture does not shock in use e.g. when sat on.
These and other objects and advantages of the invention will appear
from the following description given with reference to the
accompanying drawings in which:
FIG. 1 shows a part of a leg of an article of furniture such as a
chair in side view, said leg comprising a generally upright leg
member, a generally horizontal foot member and a joint according to
the invention therebetween,
FIG. 2 shows a part of the leg in end view,
FIG. 3 is a view from above,
FIG. 4 is a section through an upright leg member illustrating in
broken lines the nature of preferred bevelling,
FIG. 5 is an isometric projection of a part of the foot member,
and
FIG. 6 shows in schematic view the rotary machining method.
Explanation will first be given of the shock absorbing feature of
the invention and reference will thereafter be made to the manner
in which a member incorporating such a feature is associated with
the joint of the present invention and the manner in which a part
of the said joint may be machined.
Thus, in FIG. 1 there is shown the leg in side view, and in FIG. 2
there is shown a part of the leg in end view.
As illustrated the leg comprises a vertical leg member 1 (shown in
broken lines in FIG. 1) which is terminated by a foot member 2, the
members 1 and 2 being interengaged.
As illustrated in FIG. 1, the member 2 is so constructed as to be
in the form of a curve along its length concave with respect to the
ground or a supporting surface 3 on which the article of furniture
rests. In the unloaded state of the furniture, the member 2
contacts the ground only by its end regions 4 and 5. When the
article is loaded, however, the force exerted on the member 2
through the member 1 causes the former member to flatten. As a
result, contact between the ground 3 and the member 2 is no longer
only at regions 4 and 5 but also at regions therebetween including
or approaching a central region 6. The said region 6 represents the
highest point of the curved member 2 above the ground 3 and
conveniently this region 6 is directly in line with the axis of the
member 1.
As will be evident, a sudden shock transmitted to the member 2 via
the member 1 causes a temporary flattening of the member 2 so that
the shock is absorbed. Thus, a person loading, e.g. sitting on, the
article of furniture is afforded the comfort of a degree of "give"
thereby.
If desired, the member 2 is also concave in cross section as
illustrated by FIG. 2.
In one particular embodiment of the invention, the member 2 is
formed from a metal with a degree of inherent resilience suited to
the anticipated loading range for the article of furniture. As
suitable materials, there may be instanced aluminum alloy, but
other materials such as brass, bronze, cast iron or steel could be
used. In practice, it is found that a clearance of one-eighth inch
between the region 6 and the ground 3 is often advantageous.
As shown in FIG. 4, the leg member 1 comprises an elongated element
of H section--preferably extruded--with a central web 100 machined
back to a selected but not critical distance and with two outer
flanges 101, 102 radiused by similarly noncritical distances.
The nature of the foot member 2--which is preferably gravity die
cast--will now be more carefully considered with reference to FIG.
5 which shows essential features of its jointing area. Thus, as
shown, this area comprises two upright bosses 201, 202, separated
by a slot 203 and as will be evident by reference also to the
sectional shape of the leg member 1 shown in FIG. 4, the leg and
foot joint areas (or parts) are a push fit one over the other with
the central web 100 engaging in the slot 203. The engaging surfaces
are mutually secured by bonding them together with a heat-treated
resin adhesive of any suitable type.
In order to enhance the strength, simplicity and visual appeal of
the joint, various further preferred features are generally
adopted. Thus, in order to avoid the concentration of stresses in
the joint, e.g. resulting from dropping of the article of
furniture, every load area is radiused with the exception of the
vertical faces directed inwards and closing to the central web 100.
As a result, stresses are not confined to the single point of a
sharp angle but to a radiused change of direction, i.e. stresses
are not localized.
In accordance with a further preferred feature of the invention,
the radiusing of the flanges 101, 102 matches the radiusing of the
regions of the foot 2 with which there is abutment in the finished
joint.
The various areas of radiusing are not referenced in the drawing as
they are clearly visible in their own right.
In accordance with a still further preferred feature, the radiused
base 204 of the slot 203 between the two bosses 201, 202 is raised
as to a height above the level where the said bosses originate and
flanges terminate. As a result of this arrangement, there is
presented a greater area of metal to receive the impact load which
will result from dropping of the article.
It is also preferred that the central web of the member 1 be
machined short of the distance required for exact mating. Such an
arrangement is adopted not only to ease manufacturing tolerance
problems by providing a degree of clearance but also to provide a
chamber for the resin used in bonding which may be scraped down the
inner sides of the bosses and trapped.
Resin variously expands, becomes more viscous and produces gases on
heating and because of all or some of these effects any resin
trapped in the chamber would force the joint apart. Thus it is
preferred that a hole be drilled vertically through the central
part of foot 2 at region 6 which hole vents the aforementioned
chamber to atmosphere. Such a hole is shown in broken lines at 60
in FIG. 1.
As a final embellishment, recesses 205 are provided where the lower
parts of the bosses 201 and 203 merge with the remainder of the
foot 2. Such an arrangement renders the finished joint visually
more attractive and assists in stress dispersal.
Various modifications of the described article are, of course,
possible. For instance, although it is convenient to form the
various members from an aluminum alloy, other materials such as
brass, bronze, cast iron or cast steel may be used. Also, as
previously indicated, it is to be noted that joints as previously
described may be used in various articles of furniture and at
various positions and angles other than that particularly
described.
As variously shown in FIGS. 4, 5 and 6 the faces marked B and C of
the joint second part i.e. the joint lower part, are mutually truly
parallel in all planes (see FIGS. 5 and 6). The mating faces of the
first, i.e. upper, joint part are similarly parallel (see FIG. 4),
such parallelism (as opposed to tapering) being adopted for two
reasons. Firstly, because it is found that, by the use of parallel
engaging surfaces of the two joint parts, the stresses created in
the joint during use are predominantly in shear rather than in
tension, in practice such an arrangement being advantageous from
the point of view of joint strength. Secondly, because it is found
that the adoption of such a parallel relationship of the various
faces enables the preferred method of machining illustrated in FIG.
6 to be adopted.
Thus, in FIG. 6 there is illustrated in purely schematic form the
manner in which the faces B are machined in accordance with this
proposal. As shown, two parallel rotary cutters X and Y are
arranged on a common spindle Z, the cutters X and Y being bevelled
at their peripheral edges as shown to provide a bevelled region x
or y at the base of each face B,C. By the adoption of such an
arrangement and technique it is possible to machine lengths of
materials merely by movement of the cutters X, Y therealong.
The resultant bevelled edges at x, y are, of course, advantageous
for reasons concerning the localization of stresses and the
parallel faces produced are advantageous for reasons concerning
reliance for the most part on shear stresses.
As will be readily evident the adoption of such a machining
techinque also reduces overall cost.
Simultaneous reference to FIGS. 4 and 5 will assist in a better
understanding of the above references to parallelism "in all
planes."
Reference to FIG. 4 will also assist in an understanding of a
further present proposal. Thus, as shown in exaggerated manner in
FIG. 4 by broken lines at A it is preferred, in accordance with the
said further proposal, to bevel the right angles existing between
the internal flange faces of the first joint part and the web
thereof. Such bevelling avoids localization of the forces as may
happen where a right angle is used, and it is advantageous to
similarly bevel the mating faces of the second joint part.
* * * * *