US 3627359 A
Description (OCR text may contain errors)
United States Patent  Inventor Richard D. Paul Mentor, Ohio  Appl. No. 902  Filed Jan. 6, 1970  Patented Dec. 14, 1971  Assignee National Screen Service Corporation New York, N.Y.
 FRAME CORNER LOCK 4 Claims, 8 Drawing Figs.
 US. Cl 287/ 189.36",
52/656, 160/381, 287/54 C  lnt.Cl F16b 7/16  Field of Search 287/1 89.36 1-1, 20.92 C, 20.92 D, 54 A, 54 C; 160/381; 52/656  References Cited UNITED STATES PATENTS 3,191,243 6/1965 Fernberg et al 287/20.92 C
l i 34s lh 54 7 Primary Examiner- David J. Williamowsky Assistant Examiner-Wayne L. Shedd Attorney-James and Franklin ABSTRACT: A corner lock for coupling adjacent frame rails of a poster frame or the like comprises angularly disposed arms each adapted to be inserted into a channel of a different adjoining rail. Each arm comprises a body part adapted to be inserted into the rail and having a resilient member of generally sinuous shape attached thereto, said member having longitudinally spaced parts respectively extending laterally beyond sides of the body portion and adapted to be engaged and resiliently forced laterally inwardly by the side of the channel. The member has a biting edge adapted to dig into a side of the channel, thereby to ensure that the corner lock does not accidentally separate from the rail.
PATENTED DEC 1 419?! SHEET 1 OF 2 FRAME CORNER LOCK The present invention relates to frames and particularly to a construction of a frame lock for securing adjacent rails of that frame. 1
The use of poster frames and the like for displaying advertising messages has become a popular method of presenting the advertisers message to the public. Frames of this type are generally provided with a slot through which an advertising poster is inserted and removed, that poster bearing the advertisers message. Frames of this type are often placed at remote locations such as along commuter rail lines and highways to advertise Broadway shows, movies, periodicals, etc. It has been found more economical to ship the frames to their eventual location in an unassembled condition and to assemble them at their point of destination rather than to ship a completely assembled frame. The four siderails which comprise the completed frame are thus generally shipped in unassembled form in a compact carton and when the rails reach the location at which the poster is to be displayed the rails are assembled to fonn the completed frame by the use of four comer locks which are put into position to couple or lock adjacent frame rails to one another in desired angular relation.
Frame locks used for this purpose should be easy to install and when once installed should provide a firm locking acfion able to resist the forces which may tend to cause the frame rail to separate. In the past it has been thought that a firm locking action necessarily entailed the use of a frame lock which required a very substantial insertion force. This is undesirable not only because of its inconvenience, which makes customers loath to use the devices, but also because it tends to cause damage to the frame locks and rails unless insertion is very carefully accomplished and because the frame lock may not be pushed all the way home, making subsequent accurate frame assembly very difiicult.
Typical known corner locks capable of performing the desired locking function are formed with a relatively resilient member which engages one of the rails of the frame channel into which the locking arm is being inserted. The engagement of the resilient member with the rail channel surface and the cantilever-produced force which results produce the desired frictional or locking engagement between the lock and the frame. Hence this frictional engagement must be of appreciable magnitude, and it exists almost as soon as the lock is inserted in the frame channels. It therefore must be overcome during virtually the entire travel of the lock from its point of first engagement with the rail to its point of final insertion.
It is also important, of course, to ensure that the corner lock, when once inserted into a given side rail, will remain secured thereto. It is risky to rely exclusively upon frictional force to attain this result. Accordingly, it has been proposed in the past that the corner lock be provided with a biting edge which is adapted to dig into a surface of the rail when the comer lock is assembled therewith. Such biting edges have been carried on the ends of elements which are laterally resiliently flexible, the lateral resilient force involved being relied upon to cause the engagement between the biting edge and the channel wall. However, the insertion of the comer lock into the channel acts to deform the resilient part in a direction opposite to that of biting engagement, and therefore the biting action is not as reliable as one would desire.
It is the prime object of the present invention to provide a comer frame lock which may be readily inserted into place within the frame rail by the application of a minimum insertion force, and which when inserted in the rail securely retains the lock in position in the frame rail.
It is a further object of this invention to provide a comer lock which is utilized in the assembly of a poster frame or the like and which may be inserted in and locked to a rail in a virtually foolproof manner and without the likelihood of damage to rail or lock.
It is another object of the present invention to provide a corner framer lock which is sturdy and reliable in operation and which can be readily and inexpensively fabricated in large quantities.
It is yet another object of the present invention to so design the corner look as to provide both frictional and biting forces acting to retain the comer lock assembled with the rails.
It is a still further object of the present invention to so design the comer lock that the distortion thereof when it is inserted into a rail channel acts to intensify the degree to which the biting edge on the comer lock digs into the channel surface, thereby greatly enhancing the security of the assembly.
To these ends, the comer lock of the present invention comprises a pair of angularly disposed arms each of which is adapted to be respectively inserted into the channel provided in adjoining frame rails. Each of the arms is provided with a body portion from which a generally sinuously shaped resilient member extends. The sinuously shaped member has longitudinally spaced parts extending laterally beyond one or both sides of the arm body portion, those parts being adapted to be engaged and laterally compressed by the sidewalls of the channel into which the arm is inserted, thereby to provide a substantial frictional force tending to retain the arm in the channel. In addition, the resilient member is provided with a biting edge which also extends out laterally beyond the body portion, and the lateral compression of the laterally extending parts of the resilient member act on that resilient member in such a manner as to tend to force the biting edge into the opposed surface of the rail channel. When, as is preferred and as is here specifically disclosed, the resilient member extends in a direction opposite to the insertion direction of the am, the lateral compression of the resilient member tends to cause that member to elongate, thereby urging the biting edge forwardly so as to firmly dig into the corresponding channel sur face. Any attempt to separate the look from the rail tends to cause the resilient member to shorten in length, but this action is reliably and firmly resisted by the laterally compressed portions of the resilient member.
To the accomplishment of the above, and to such other objects as may hereinafter appear, the present invention relates to a construction of a frame comer lock as defined in the accompanying claims, and as described in this specification, taken together with the accompanying drawings, in which:
FIG. 1 is a front elevation of a poster frame, partly broken away, the frame being in its assembled condition, in which the adjoining rails forming the frame are secured to one another by the frame comer lock of this invention;
FIG. 2 is a side elevation of the comer lock of this invention;
FIG. 3 is an end elevation of the comer lock of FIG. 2 as viewed from the right-hand end thereof;
FIG. 4 is a fragmentary elevational view on a greatly enlarged scale of the lock of FIG. 2 showing one arm of the lock being inserted into the rail channel;
FIG. 4A is a fragmentary top plan view of a portion of the assembly of FIG. 4;
FIG. 5 is a view similar to that of FIG. 4 illustrating the position of the lock arm after it has been completely inserted into the rail channel;
FIG. 6 is a cross-sectional view taken along the line 6-6 of FIG. 5; and
FIG. 7 is a cross-sectional view taken along the line 77 of FIG. 5.
FIG. 1 illustrates a poster frame generally designated 10 in its assembled position in which the side frame rails 12 and 14 and top and bottom frame rails I6 and 18 are securely held together by means of four corner locks 20 of this invention. An advertising poster 22 or the like is inserted into the frame 10 and is exposed in the central open portion defined by the rails 12-18.
Referring now to FIGS. 2 and 3, the comer lock 20 of this invention comprises a pair of angularly disposed arms 24 and 26 which are herein specifically disclosed as being substantially at right angles to one another. Each arm of the corner lock is adapted to enter a channel provided in a different one of adjoining frame rails such as frame rails 12 and 16, or 12 and 18. As the arms 24, 26 are substantially identical in construction only one of the arms will be herein described in detail, it being understood that that description will be equally applicable to the other arm of corner lock 20.
Each arm 24, 26 comprises a body portion 28 having a leading end 30, a bottom edge 32 and a top edge 34, A recess 36 is formed in the top edge 34 at a location spaced from the leading edge 30, and a member generally designated 38 is secured to the body portion 28 and extends into that recess 36, the member 38 being secured to the body portion 28 at 40 and having a free end 42. It is preferred that the member 38 be formed integrally withthe remainder of the lock 20, so that the entire lock unit can be fonned in one piece from suitable sheet material, as by a stamping operation.
It is the member 38 which acts primarily to secure the comer lock 20 in operative association with a given rail. To that end it is generally sinuous in shape, as may perhaps best be seen from FIGS. 3 and 4A, the member 38 first extending laterally beyond one side of the arm 24 to define part 44, then extending beyond the other side of the arm 24 to define part 46 and then extending beyond the first-mentioned side of the arm 24 to define part 48, the part 48 also defining the free end 42 of the member 38. The lateral spacing between the outer surfaces of parts 44 and 46 on opposite sides of the arm 24 is selected to be somewhat greater than the maximum accepted width of the frame rail channel into which the arm 24 is adapted to be inserted. In the form here specifically disclosed, and as preferred, the biting edge 48 may extend out beyond the corresponding side of the arm 24 to a somewhat greater degree than the nonbiting part 44 on the same side of the arm 24. The member 38 is formed of an appropriate resilient material and preferably, and as here specifically disclosed, extends from its associated body portion 28 in a direction opposite to that of arm insertion into a rail channel, that is to say, it extends from the area 40 where it is secured to the body portion 28 in a direction longitudinally away from the leading end 30.
F [G8, 4 7 illustrate the manner in which arm 24 is inserted into upper and lower channels 50 and 51 respectively formed in one of the rails, such as 18, defining the poster frame 10. The upper channel 50 has upper surface 52 and side surfaces 56. The lower channel 51 has lower surfaces 54 and side surfaces 56. The vertical spacing between surfaces 52 and 54 is substantially the same as the vertical spacing between the lower and upper edges 32, 34 of the comer lock arm 24. The lateral spacing between the surfaces 56 of each channel 50 and 51 is somewhat greater than the thickness of the comer lock arm 24, but is somewhat less than the normal lateral spacing between the outer extremities of parts 44 and 46 extending to opposite sides of the arm 24. (Although the resilient member 38 is here shown as having some parts (44, 48) extending to one side of the arm 24, and other parts (46) extending to the other side of that arm, it will be appreciated that it is not essential that these parts extend to both sides of the arm 24, so long as the overall thickness of the arm 24 considered together with the laterally extending parts of the member 38 is greater than the lateral spacing between the side channel surfaces 56.)
The leading end 30 of the arm 24 is first inserted into the exposed open ends of the channels 50 and 51 at the end of the rail 18. The upper and lower edges 32 and 34 of the arm 24 slide over the lower and upper surfaces 54 and 52 of the channels 51 and 50 respectively with minimal frictional resistance, thereby permitting the relatively easy initial insertion of the arm 24 into the channel 50. This easy initial insertion continues through the position shown in FIGS. 4 and 4A until the first laterally extending part of the resilient member 38 (here shown as the part 44) enters the upper channel 50 (or, if the channel 50 is wider than the combined thickness of the arm 24 and the distance by which the part 44 extends laterally out therefrom, until the second laterally extending part 46 enters the channel 50). Once that portion of the arm 24 which has an effective thickness greater than the width of the channel 50 enters that channel, one or more of the laterally extending parts 44 48 defined by the resilient member 38 will be positively laterally moved inwardly through engagement with the channel side surfaces 56. The consequent resilient deformation of the member 38 will cause the parts 44, 46 thus engaged and laterally compressed by the channel surfaces 56 to create a substantial frictional force against those surfaces 56. This frictional force will tend to retain the arm 24 assembled with the channel 18. In addition, the lateral deformation of the member 38 will cause that member to elongate its free end 42 carrying the biting edge 48 will move away from the connecting area 40.
When, as is shown in FIGS. 5 7, the arm 24 has been inserted fully into the channel 50, all of the laterally extending parts 44 48 of the resilient member 38 will be laterally compressed by the side surfaces 56 of the channel 50. Thus, a strong frictional force will be developed tending to restrain separation of the comer lock from the rail. In addition, since one of the laterally extending parts, the part 48, is defined by a biting edge, that edge will tend to dig into the side channel surface 56. This provides an important additional retention action. Additionally, and significantly, the force tending to urge the biting edge 48 into the channel sidewall 56 is not dependent upon the mere cantilever resilience of the am 38, which alone would be only of minimal magnitude. It is instead determined in a large part by the forces generated in the lateral resiliently compressed parts 44 and 46, the compression of those parts, in elongating the member 38, very strongly urging the biting edge 48 into the channel surface 56. Any attempt to withdraw the arm 24 from the channel 50 will tend to cause the member 38 to shorten in length, but this tendency will be very powerfully resisted by the action of the member 44, 46 against the channel side surfaces 56. Hence, although the arm 24 may be inserted into the channel 50 very readily, with practically no resistance for the first portion of its insertion movement, and with not a very great resistance during the remainder of its insertion movement, it can be removed from that rail only upon the exertion of an extremely strong force, if at all.
The corner lock of this invention can be readily fabricated from a single piece of material and is thus relatively cheap to manufacture and simple to use. It is at least as easy to assemble with associated frame rails as prior art devices, and is much more reliably retained in operative association with those rails than prior art devices.
It will be understood that the single embodiment of the present invention herein specifically disclosed it but exemplary, and that many changes may be made therein, all within the scope of the present invention as defined in the following claims.
1. A corner lock for coupling adjacent frame rails each having open-ended longitudinal channels, said lock comprising a pair of angularly disposed arms each adapted to be inserted into a channel of a different frame rail, at least one of said arms comprising a body portion adapted to be inserted into its corresponding channel via the open end thereof, said body portion having a leading end which is first to be thus inserted and a trailing portion which is inserted into said channel after said leading end, and, secured to said body portion and extending therefrom in a direction generally from said leading end toward said trailing portion, a resilient member of generally sinuous shape such as to have relatively longitudinally spaced parts respectively extending laterally beyond at least one side of said body portion and with the overall thickness of said sinuous member being equal to or greater than the thickness of the channels into which said parts are inserted, said parts being laterally unsupported and adapted to be engaged by the sides of the said channel and resiliently forced laterally inwardly, thereby elongating said member, said member having a free end which comprises one of said parts, said member extending generally in a direction from said leading end of said body portion toward said trailing portion thereof, said free end being located remote from said leading end of said body portion and terminating in a biting 6 edge, whereby said biting edge is biased to dig into a side of 3. The comer lock of claim 2, in which said body has a said channel when inserted thereinto. recess formed in the top edge thereof, said resilient member 2. The comer lock of claim l, in which said biting edge of being received in said recess.
said member normally extends laterally beyond the cor- The comfir lock of claim whlfih y has a responding side of said body by a greater distance than said 5 f P edge thereof" smd resilient member other member parts on that side of said body extend beyond bemg recewed m recess" said side.