Note: Descriptions are shown in the official language in which they were submitted.
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CLAMPING BRACKET FOR PICTURE FR~MES
The present invention relates to clamping brackets and,
in particular, to clamping brackets of the type used to
secure abutting channel members such as picture frame sect-
ions in the desired angular relationship.
The picture frame disclosed and claimed in the applicant's
prior Canadian Patent No. 881,000, dated September 14, 1971
has enjoyed very remarkable commercial success. That patent
discloses a picture frame constructed of a plurality of
channel section frame members which are secured together at
their corners by clamping brackets. The picture frame of
Canadian Patent 881,000 is easily assembled and disassembled
and enables the frame to be dismantled and re-used as occas-
ion may require.
The present invention provides an easily assembled and
disassembed picture frame making use of extruded metal frame
members of channel form secured together by brackets which
provide for a joint of exceptional strength and rigidity.
Furthermore, the clamping bracket of the present invention
will secure the corner joints of such a picture frame with-
out damage to the extruded channel from elements and withoutdamage to the material being framed should the material
extend right into the vertex of the frame members.
A preferred embodiment of the invention is disclosed in
the accompanying drawings in which like reference numerals
~k
il~7~ ~3~
_ -- 2
denote like parts and in which:
Fig. 1 is a general perspective view, partly exploded,
showing a picture frame embodying clamping brackets of the
present invention;
Fig. 2 is an exploded perspective view showing, in en-
larged detail, the clamping bracket and its relationship to
the extruded metal frame elements;
Fig. 3 is a perspective view of the clamping element of
Fig. 2 taken from the opposite side;
Fig. 4 is a section view along line 4-4 of Fig. 2;
Fig. 5 is a view similar to Fig. 1 showing an alternat-
ive configuration of picture frame that is possible with
the present invention;
Fig. 6 is a view similar to Fig. 4 but showing a some-
what modified version of the clamping bracket of the present
invention;
Fig. 7 is a view similar to Fig. 6 showing the config-
uration of the clamping bracket when in the tightened condit-
ion, and
Fig. 8 is a perspective view similar to Fig. 3 but on
an enlarged scale showing the modified clamping bracket of
Figs. 6 and 7.
Referring to Fig. 1, a picture frame can be seen to
comprise four framing elements 10 secured toyether in end-
to-end abutment to enclose a defined area 11 within which
the picture or other article to be framed is mounted. The
framing elements 10 are secured together at their corners
by the clamping brackets 12 of the present invention which
will be described in greater detail below.
In Fig. 2, an enlarged view of a typical corner of a
picture frame such as that illustrated in Fig. 1 is illust-
rated. The framing element 10 may be seen to comprise a
metal extrusion formed to provide a channel 13 defined by
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a bottom wall 14, a pair of opposed side walls 15 and 16
and a pair of inwardly turned lips or flanges 17 and 18.
The channel 13 is of such a size and configuration that it
snugly receives the clamping bracket 12.
The framing element 10 additionally includes a further
flange 19 and an inwardly turned lip or flange 20 to provide
a groove 21 within which the edge of the framing glass 22
and mat 23 may be received.
Referring now to Figs. 2, 3 and 4, the clamping bracket
12 of the present invention may be seen to comprise a pair
of integral bracket arms 24 and 25 which lie at an angle to
each other equal to the desired angle between adjacent frame
or channel members. In the embodiment illustrated in Figs.
1, 2 and 3, the arms 24 and 25 lie at 90 to each other.
Each bracket arm is provided with a top wall 26 (see
Fig. 4), a pair of integral side walls 27 and 28 and
(see Fig. 3)a pair of half bottom walls 29 and 30. The half
bottom walls 29 and 30 are integral with the side walls and
extend inwardly therefrom.
The inner edges of each pair of half bottom walls
present spaced, opposed, facing surfaces which, in the embod-
iment of Figs. 2, 3 and 4 are constituted by upwardly and
outwardly inclined flanges 31 and 32 which present opposed
cam surfaces. A screw 33 is threaded into a threaded apera-
ture 34 in the top wall 26, the axis of the screw bisecting
the space between the spaced, opposed, facing surfaces and,
in the case of the embodiment of Figs. 2, 3 and 4, bisecting
the angle between the opposed cam surfaces.
In operation, the clamping bracket as previously des-
cribed provides for an extremely strong and rigid connection
between adjacent framing elements 10.
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~ - 4
In order to secure the two framing elements 10 together,
the clamping bracket is inserted in the adjacent channel 13
of adjacent framing elements 10 which have previously been
mitred at an appropriate angle (to provide a right angle joint
in Fig. 2). The framing elements 10 are then moved together
so as to provide a tight, neat and closed joint whereupon
the screws 33 are turned to advance them into the clamping
bracket.
Referring to Fig. 4, it will be seen that as the screw
33 is advanced towards the cam surfaces, the conical tip 35
with which the screw is provided will engage the cam surfaces
of flanges 31 and 32. This engagement will produce a clamping
action in both senses of two mutually perpendicular directions.
First, the screw advancing along its axis and engaging
the flanges 31 and 32 will exert a force and a reaction in
both senses of the direction indicated by the arrows 36.
Thus, a clamping action will be set up between the top wall
26 and the inwardly turned lips or flanges 17 and 18 of the
channel and between the half bottom walls 29 and 30 and the
wall 14 of the channel.
Simultaneously, the cam action of the conical tip 35
on the flanges 31 and 32 will tend to move the half bottom
walls and the adjacent portions of the side walls 27 and 28
in the directions of the arrows 37 and 38 thus exerting a
clamping action between the side walls 27 and 28 of the
clamping member and the side walls 15 and 16 of the channel.
From the preceding description, it can be readily seen
that the clamping member of the present invention provides
for an extremely firm, rigid and secure method of joining
the frame elements 10 of the picture frame illustrated in
Fig. 1.
Turning now to Figs. 6, 7 and 8, a slightly modified
11'784;~9
.~ 5
versio~ of the clamping bracket is disclsoed.
In Fig. 6, it will be seen that the flanges 31 and 32
providing the cam surfaces are absent, and, instead, the
spaced, opposed, facing surfaces are constituted simply by
the inner edges of the half bottom walls. Conveniently,
these inner eages are provided with spaced, parallel serat-
ions aligned along said edge surfaces and normal to the axis
of the screw.
Referring specifically now to Fig. 6, the edge surfaces
50 are provided with serations 51 and the screw 52, instead
of having a conical tip such as the conical tip 35 of Fig.
4, is provided with a tip that is a frustum of a cone 53, the
frusto-conical surface being provided with screw threads 54.
Conveniently, these screw threads 54 may be of a finer pitch
than the screw threads 55 on the shank of the screw.
Referring now to Fig. 7, it can be seen that as the
screw 52 is rotated, the threads 54 on its frusto-conical
tip will engage the serations 51 on the edge surfaces 50 of
the half bottom walls 56 and 57 and will tend to lift them
upwardly away from the ad~acent wall of the channel in the
framing element 10 and, in doing so, will move them towards
the base of the frusto-conical tip and will, thus, urge
them apart to cause them tG expand in the direction of the
arrows 58 to cause them to clamp tightly against the opposed
side walls of the channel.
Ideally, the separation between the serated edges 51
and the diameter of the tip of the frusto-conical tip 53 of
the screw 52 will be such that the blunt end 59 of the screw
will engage or almost engage the opposing wall of the chan-
nel at the same moment as the threads 54 on the frusto-
conical tip engage the serations 51. Thus, a relatively
small amount of further rGtation of the screw 52 will cause
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the threads 54 to engage the serations and drive the half
bottom walls 56 and 57 apart and cause the blunt end of the
screw 59 to engage the opposing wall of the channel so as
to provide clamping within the channel in both senses of two
mutually perpendicular directions in a manner similar to
that explained with respect to Figure 4.
A feature that is common to both embodiments of the
invention is best illustrated in Figs. 3 and 8. In Fig. 3,
the side walls of the clamping brackets are provided with
slots 60 which extend from the free edges of the side walls
substantially to the top wall 26. The purpose of the slots
60 is to increase the flexibility of the side walls to
permit the conical tip 35 of the screw 33 to act upon the
flanges 31 and 32 in order to drive the half bottom walls
apart to provide for clamping in the direction of the arrows
37 and 38.
Similarly, in the embodiment of Fig. 8, slots 61 are
provided in the same location for precisely the same purpose.
Finally, with reference to Fig. 5, it can be seen that
picture frames of a somewhat unconventional configuration can,
of course, be produced using the clamping device of the
present invention. In order to produce a picture frame hav-
ing the configuration of Fig. 5, it is merely necessary that
the angle between the arms of the clamping bracket 12 be
chosen as to provide an appropriate angle between adjacent
framing elements 10.
From the foreoing description, it is believed apparent
that a clamping bracket has been disclosed which has the
virtures of rigidity, strength and simplicity and which
enable a picture frame to be securely constructed with no
tools other than a screw driver and which enable the same
picture frame to be readily disassembled for re-use as the
439
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occasion may require.
While preferred embodiments of the invention have been
described in detail in the disclosure, and illustrated in
the drawings, the scope o~ the invention is intended to be
limited only by the appended claims.
