Picture frame assembly

A picture frame made of metal extrusions of identical cross sectional shape is assembled at its corners by the use of corner plates and cam operating buttons. The plates have cam ramps formed therein and the buttons have integral cam lugs. A quarter turn with a screwdriver will tighten or loosen the assembly to close or open a corner.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates generally to picture frames, and more particularly 
to means facilitating assembly of metal picture frames. 
2. Description of the Prior Art 
The prior art has disclosed various ways of assembling picture frames. Two 
patents of particular interest in this regard are U.S. Pat. No. 3,534,490 
issued Oct. 20, 1970 to D. P. Herbert, and U.S. Pat. No. 3,965,601 issued 
June 29, 1976 to Helmar Nielsen. In the former of these patents, the frame 
members are metal extrusions and are held together at the corners by 
angled members having set screws threaded therein and bearing on portions 
of the frame members to lock the angle members in the frame members at the 
corners. In the Nielsen patent, the frame members are also made of metal 
extrusions of a cross section similar to but slightly different from those 
in Herbert. In the Nielsen construction, several different types of corner 
pieces are employed with set screws to hold the corners together. 
Although the Herbert patent discloses one way of holding extrusions 
together at corners to form a picture frame, and the Nielsen patent shows 
another way to do the same thing and, at the same time, force the corners 
together at the front of the frame, both have some disadvantages. One 
primary disadvantage can be best recognized when one considers the fact 
that there is a significant market for non-professionals, who wish to do 
their own work in framing pictures. Occasionally such individuals do not 
get the corners together quite adequately. The Nielsen patent represents 
an effort to improve the ability of an individual to make a good corner. 
But in one embodiment of Nielsen, where the L-shaped bearing plate 28 is 
used, this involves an extra piece at each of the corners, thus increasing 
the expense, weight, and number of pieces the user must deal with at each 
corner. In the other embodiments, where only one piece is used, and in the 
Herbert construction, the set screw bears on the aluminum frame itself. If 
the corner is not properly assembled the first time, and the set screw is 
tightened in place, it will make it difficult to ever correctly assemble 
the corner thereafter. The reason for this is the fact that, once 
tightened, the set screw normally leaves a dent in the metal. At each 
subsequent reassembly of the corner, the set screw tends to re-seat itself 
in the dent made the first time. 
SUMMARY OF THE INVENTION 
Described briefly, according to a typical embodiment of the present 
invention, a frame assembly is provided of a plurality of framing members 
having a generally C-shaped cross section. Connector assemblies are 
located at the end-to-end junctions of these members. Each connector 
assembly has a bearing piece with two apertures therein. One aperture 
faces a wall of the C in one of the members at the joint, and the other 
aperture faces a wall of the C in the other member at the joint. A bearing 
pad device is located at each of the apertures, each pad having a stem 
received in the aperture, and a flange portion. The large face of the 
flange portion provides a bearing pad face to engage with the wall of the 
C, while a cam lug is provided on the face of the flange opposite the 
large face. This cam lug engages a cam ramp formed in the connector piece. 
A tool receiver is provided in the end of the stem for access by a tool 
which, upon turning of the bearing pad device in the aperture, will cause 
the cam lugs to ride up the cam ramps and tighten the connector piece and 
bearing pad device in the frame member. In this way, the corners can be 
assembled and locked.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring now to the drawings in detail, and particularly to FIG. 1, the 
picture frame assembly of FIG. 1 includes upper and lower framing members 
11 and side framing members 12 mounting a picture therein with the picture 
backing shown at 13. All four of the framing members shown in this 
embodiment are of identical cross sectional shape as shown in FIG. 2 and 
can be made of aluminum extrusions or of other materials by appropriate 
processing. They are mitered at the ends as shown in FIG. 1 with the angle 
being appropriate to the number of sides in the frame. In the 
illustration, a 45.degree. angle is used for a rectangular frame. For a 
hexagon or other polygonal shape, the angles would be appropriate to the 
particular shape. 
In FIG. 1, where we are looking at the rear of the frame, one can see the 
rear face of each of the four framing members. As shown in FIG. 2, the 
rear face of member 11 is provided by spaced co-planar flanges 14 and 16 
whose inner surfaces 14A and 16A provide a bearing wall in the framing 
member, as will be seen. The front face of the frame is provided by a 
front flange 17 in a plane parallel to that of the plane of the inside 
walls of flanges 14 and 16. 
The flanges 14 and 16 are parallel to a wall portion 18 whose face 18A is 
parallel to and faces the walls 14A and 16A of the flanges 14 and 16. 
These, together with the portions 19 and 21 of the member 11, provide a 
C-shaped portion of the frame member. This portion cooperates with the 
flange 17 and portion 22 to form a channel 23 to receive the picture, 
backing 13 (FIG. 1) and any external covering such as glass or plastic 
also in channel 23 to provide protection for the front of the picture (not 
shown). The C-shaped portion provides a track with a rearwardly opening 
slot 24 therein for purposes which will soon be described. Because the 
cross sectional shape of all of the framing members is the same, the slot 
24 extends the whole length of each of the frame members. For purposes of 
the present invention, it is not necessary that the track and slot be 
uninterrupted throughout the entire length of the members. It is shown 
this way, with the showing of corner connector assemblies omitted from 
FIG. 1, to illustrate that it is most convenient for all framing members 
to be of the same material with identical cross section. 
Referring now to FIGS. 3, 4 and 5, FIG. 3 shows a metal plate. A convenient 
material is cold rolled strip steel of prime quality, one-half hard. As an 
example, for a frame having a nominally one-half inch wide track, the 
plate of FIGS. 3-5 can be stamped from a steel strip 2 inches wide and 
0.050 inches thick. It has a pair of apertures 26 and 27 punched therein 
at the longitudinal and lateral centers of the two legs of the L-shape of 
the plate. The L-shaped plate is for use in frames which are rectangular. 
For frames of other polygonal shapes, the plate would be of an angular 
shape other than right angle. 
At each aperture, two semicircular cam ramps such as 28 and 29 at aperture 
26 are cold formed in the plate. A depression 28A is formed in the face 31 
of the plate to form the cam ramp 28 in the opposite face. Similarly, a 
depression 28A is formed in face 31 to provide the cam ramp 29. Since this 
plate bears against the frame member inside walls 14A and 16A (FIG. 2) in 
the assembly, as a reaction against a cam force applied as will be 
described, the surface 31 will be called a "bearing surface" and this 
piece will be hereafter referred to in this description as a "bearing 
plate". A depression 32 is provided in the bearing surface in a specific 
orientation with reference to the commencement and conclusion of the cam 
ramps to assist the user in the assembly of the frame according to the 
present invention. The lines 28B and 29B at the ends of the depressions 
28A an 29A, respectively, have counterpart abutments on the opposite face 
of the bearing plate at the "high" ends of the cams. The orientation of 
these is preferably 45.degree. from the longitudinal axis of the leg of 
the plate in which the associated aperture is located. This relationship 
will be observed upon reference also to the cam ramp depressions in the 
bearing face 31 adjacent the aperture 27. The index arrow 33 associated 
with the aperture 27 and its associated cams has the same relationship to 
that aperture and its associated cams as the arrow 32 has with reference 
to the aperture 26 and its associated cams. 
Reference to FIG. 5 shows, for example, where the depressions 29A ends at 
the end abutment 29B with the counterpart end abutment 29C at the "high" 
end 29D of the ramp 29. This is typical of each of the cams in this 
embodiment. The cams associated with aperture 27 and arrow 33 are 34 and 
36 with the end of cam 34 being shown at 34C. The high point of cam 34 is 
at 34D and the high point of cam 36 is at 36D. 
FIGS. 6 and 7 show a pressure pad according to the typical embodiment of 
the present invention. This pad is typically circular about an axis 37, 
and includes a stem 38 and flange 39. The stem has a tool receiver therein 
which is shown at 41 as a screwdriver slot. The flange 39 has a bearing 
face 42 which is smooth and flat across its entire face. The rear face 43 
of the flange has a pair of integral radially extending lugs 44 and 46 
thereon which are semi-circular in shape as shown in FIG. 6. 
FIGS. 8 and 9 show two views of a corner assembly, which is typical of each 
of the four corners of this frame assembly of FIG. 1. The two legs of the 
corner bearing plate 25 are disposed respectively in the channels formed 
by the C-shaped portions of the framing members 11 and 12. A bearing pad 
device is provided at each of the two apertures 26 and 27. The stem of 
each such device is received in the respective aperture. In order to be 
able to insert the corner connector assembly in the respective C-shaped 
channel of the corresponding frame member, it is necessary that the 
bearing pad cam operating lugs 44 and 46 be away from the high points on 
the cams, and preferably at the commencement of the cam ramps on the free 
face 31F of the bearing plate 25. In this way, the bearing pad face 42 has 
ample clearance space 47 from the wall 18A of the framing member. The stem 
end 40, with the screwdriver slot 41 therein is exposed in the slot 24. To 
tighten the connector plate and bearing pad in the C-shaped channel or 
track, it is necessary only to turn the pad approximately one-quarter 
turn. This will cause the cam lugs 44 and 46 to ride up the cam ramps 29 
and 28, respectively, until the pad 42 engages the wall 18A and forces the 
bearing surface 31 against the flange walls 14A and 16A. The connector 
assembly has already been tightened in this way in the member 12. Thus, 
FIGS. 8 and 9 show the connector assembly loose in the member 11 and tight 
in the member 12, to show the two different conditions. 
In order to assist the user in assembly of the unit, to facilitate entry of 
the plates and bearing pads in the respective frame members, the outer end 
40 of the stem of the bearing pad is provided with indicator pointers 48. 
There are so related to the cam lugs on the bearing pads that, when 
aligned with the pointers 32 and 33 on the bearing plate legs, the lugs 
are at the low points on the cams. This indicates a release condition. 
When the bearing pad pointers are located transverse to the related 
pointer in the associated aperture, the cam lugs are fairly high on the 
cam ramps. 
The screwdriver slot could have a different orientation with reference to 
the lug such as 90.degree. from the orientation shown, and the slot could 
then be used as an index indicator, instead of the pointers 48. However, 
other types of tool receivers such as an Allen wrench socket or Phillips 
screwdriver socket might also be used. In that event, a specific index 
indicator such as a pointer 48 would be desirable. 
FIGS. 10 and 11 show an alternate embodiment of the corner plate. In this 
embodiment, instead of the cam ramps being formed as shown in the previous 
embodiment, forming with lancing is used. Apertures are provided at 51 and 
52 in the respective legs. At each of the apertures, the material is 
lanced as at 53 to provide a cantilever arm 54 with a cam surface 56 at an 
appropriate ramp angle adjacent the bearing pad stem piloting edge 57. 
Similarly, the leg is lanced at 58 to provide another cantilever portion 
59 with a cam ramp 61 thereon adjacent the bearing pad piloting edge 62. 
Appropriate orientation indicators such as 63 may be provided. The 
material used would be preferably high carbon spring steel. This corner 
bearing plate can be used in the same way as that described above with 
reference to the preferred embodiment. 
While the invention has been illustrated and described in detail in the 
drawings and foregoing description, the same is to be considered as 
illustrative and not restrictive in character, it being understood that 
only the preferred embodiment has been shown and described and that all 
changes and modifications that come within the spirit of the invention are 
desired to be protected.