US 3769920 A
A folding table leg locking device, for use in securing a table leg rail follower at a fixed position along a horizontally-extending flanged, channel-shaped rail on the underside of a folding table. The device is provided with a spring loaded catch having at least two tongues of unequal length supported on a support pin by brackets formed integrally from the flanges of the channel rail. The brackets including ears for distributing locking impact forces along the rail follower.
Description (OCR text may contain errors)
United States Patent 1 1 Weiss 1 Nov. 6, 1973 FOLDING TABLE LEG LOCKING DEVICE  Inventor: Samuel Herman Weiss, 2800 W.
Albion, Chicago, Ill. 60645  Filed: Aug. 9, 1971  App]. No.: 169,926
 US. Cl. 108/133 51] Int. Cl 470 3/08  Field of Search 108/131, 132, 133,
'  References Cited UNITED STATES PATENTS 2,664,329 12/1953 Kraska 108/133 2,672,387 3/1954 Barricks..... 108/133 2,784,042 3/1957 Clapper 108/132 Primary ExaminerFrancis K. Zugel Att0meyMerriam, Marshall, Shapiro & Klose  ABSTRACT A folding table leg locking device, for use in securing a table leg rail follower at a fixed position along a horizontally-extending flanged, channel-shaped rail on the underside of a folding table. The device is provided with a spring loaded catch having at least two tongues of unequal length supported on a support pin by brackets formed integrally from the flanges of the channel rail. The brackets including ears for distributing locking impact forces along the rail follower.
1 Claim, 9 Drawing Figures Lay l08/l29 FOLDING TABLE LEG LOCKING DEVICE BACKGROUND OF THE INVENTION The present invention relates generally to folding table leg locking devices and more particularly to an improved spring loaded device for securing table leg rail followers at a fixed position along a horizontallyextending flanged channel rail affixed to the underside of a folding table.
Typical of the leg locking devices presently used in the art are those shown in US. Pat. No. 2,672,387. Such devices ordinarily are composed of a relatively large number of separately assembled elements; are costly to construct, difficult to install and require constant maintenance.
The construction costs of such devices are high due to the requirement that certain elements be molded or machined in alternate forms for left and right side placement. Because of the multiplicity of elements, installation 'is difficult, time consuming and, hence, costly. Because the elements are mounted with screws and/ or nuts and bolts, the devices, once installed, require periodic maintenance in the form of tightening and straightening.
Further, certain aspects of the design of such devices make inherent the probability of substantial damage to the rail followers held in place by the devices and also necessitate providing auxiliary blocks or platforms to maintain catch elements in proper position for locking.
BRIEF SUMMARY OF THE INVENTION Locking devices of the present invention are easily constructed, easily installed, substantially maintenance-free, require no auxiliary support elements and yet provide safe, secure fastening of table legs while minimizing wear on rail followers.
More particularly, locking devices of the invention are used with flanged, channel-shaped rails and include a spring loaded, rail follower catch supported by brackets integrally formed of the flanges of the rail. The catch is provided with alternating tongues and slots in a manner allowing secure fastening while eliminating the need for support blocks or platforms. Ears are integrally formed on the catch support brackets and function to distribute locking impact forces which result in wear and damage to the rail follower.
Further aspects and advantages of the present invention will be apparent from the following description of a preferred embodiment thereof, reference being made to the following drawings.
BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is an isometric view of a folding table of the type on which locking devices of the invention may be used.
FIG. 2 is a fragmentary bottom plan view of the table of FIG. 1, showing a locking device of the invention and having legs in folded position.
FIG. 3 is a sectional view taken along line 33 of FIG. 2.
FIG. 4 is a fragmentary sectional view taken along line 4-4 of FIG. 2.
FIG. 5 is a fragmentary sectional elevational view of a folding table having legs in an unfolded position and secured in place by a locking device of the invention.
FIG. 6 is an isometric view of a locking device of the invention.
FIG. 7 is a sectional view taken along line FIG. 6.
FIG. 8 is a side elevational view of a folding table leg rail follower in a position just prior to being secured by a locking device of the invention.
FIG. 9 is a side elevational view of a folding table leg rail follower in a secured position in a locking device of the invention.
DESCRIPTION OF A PREFERRED EMBODIMENT FIGS. 1 and 2 show a folding table 10 of the type upon which a locking device of the invention, indicated generally at 11, maybe employed. Table 10 has a table top portion 12 of wood, metal or composite material supportable on pairs of wood or metal legs 13 and 14 when in an unfolded position. Legs 13 and 14 are of identical construction. Legs 13, for example, include base elements 13a, 13a interconnected to form a U- shape by yoke element 13b. Extending from yoke 13b are mid-sections 13c, 13c which interconnect with transverse element 13d. Transverse elements 13d, 14d are pivotally attached to the underside 15 of table top 12 by clamp members 16. Pairs of angled brace members 17, 17 and 18, 18 are individually pivotally fastened to legs 13 and 14 respectively by bolting elements 19 at positions intermediate the length of midsections 13c, 13c, 14c, 14c.
Fastened to underside 15 of table top 12 is a horizontally extending metal rail 20 having a channel 21 defined by a channel bottom 22 with channel sides 23, 23 extending generally perpendicularly therefrom (FIG. 3). Rail flanges, 24, 24 extend at right angles outwardly from channel sides 22, 22 and generally parallel to channel bottom 22.
Brace member ends 17a, 17a, and 18a, 18a opposite the points of attachement to table legs, are pivotally attached by rivets 25 to cylindrical rail follower elements 26.
Rail followers 26 are maintained in rolling contact with rail flanges 24, 24 by means of L-shaped slide elements 27 which are pivotally attached to the rail followers by rivets or bolts 25.
In use, as the table legs are folded and unfolded, rail followers 26 roll along rail .flanges 24, 24 from an unlocked position near the center of the table (FIG. 4) to a locked or secured position at locking device 11 (FIG. 5).
Referring to FIGS. 6 and 7 locking device 11 is provided with a rail follower catch 28. Catch 28 includes a longitudinally-extendingcatch body portion 29 from one end of which a first tongue element 30 extends generally perpendicularly. Inward of and adjacent to tongue 30 is a catch slot 31. Inward of and adjacent to slot 31 is a second tongue element 32 extending generally perpendicularly from catch body 29 a distance less than that to which tongue 30 extends. Inward of and adjacent to tongue 32 is another catch body slot 33. Catch body 29 is provided with an aperture 34 for supporting catch 28 on rail 20.
Locking device 11 is further provided with a pair of catch supporting brackets 35, 35 formed integrally from rail flanges 24 extending generally perpendicunected therewith. Each bracket 35 is preferrably provided with an ear 39, adjacent slot 38, for distributing impact forces, generated upon locking of a rail follower, along a relatively larger surface of the rail follower and thus reducing wear on the follower.
A spring element 40 is provided around pin 37 and positioned in such a manner as to urge tongue 30 at all times toward contact with channel bottom 22.
Catch 28 is provided with a laterally extending tab element 41 for use in manually raising tongues 30 and 32 away from channel 21 to release a locked rail follower 26 from a secured position.
Use of expensive catch support pins having a varying diameter is avoided by providing a hollow support pin 37, retained in position after mounting on a catch 28, by a rivet 42 at each end as shown in FIG. 7.
Operation of the locking device of the invention is best illustrated with reference to FIGS. 4, 5, 8 and 9.
When table legs 13 are in a folded position (FIG. 4), locking device 11 has the tip 30a of tongue 30 urged into contact with channel bottom 22 by spring 40. Rail follower 26 is at a position along channel rail 20 relatively remote from locking device 11.
As legs 13 are moved downward and away from the underside 15 of table top 12 toward a vertical position, rail follower 26 slides along rail flanges 24, 24 until follower 26 contacts the curved forward edge 30b of tongue 30. Due to the curvature of edge 30b, continued application of force on legs 13 will cause rail follower 26 to displace tongue 30 away from channel bottom 22 (FIG. 8). Once rail follower 26 has moved past tongue tip 30a, spring 40 moves tip 300 toward channel bottom 22, securing rail follower 26 in slot 31 and catch 28 presses follower 26 against rail flanges 24, 24 (FIG. 5). Slot 31 thus functions as a safety slot to insure that legs 13 will not collapse if the legs are not moved to a completely vertical position in the unfolding procedure.
Further application of force on legs 13 causes rail follower 26 to contact curved edge 32b of tongue 32, displacing the tongue away from channel 21. As rail follower 26 is moved past tip 32a of tongue 32, tip 32a is moved toward channel 21 by action of spring 40, engaging rail follower 26 in tongue slot 33 and bracket slots 38, 38 thus securing legs 13 in a locked verticle position (FIG. 9).
When legs 13 are to be collapsed from the vertical position, tab element 41 is depressed toward table underside 15, freeing rail follower 26 from engagement in tongue slot 33, and thus permitting movement of follower 26 along rail away from locking device 11.
Obviously, many modifications and variations of the above-described invention may be made without departing from the spirit and scope thereof. Therefore, only such limitations as are indicated in the appended claims should be placed thereon.
What is claimed is:
1. In a folding table-leg locking device for use in securing a table leg rail-follower at a fixed position along a horizontally-extending, channel-shaped flanged rail on the underside ofa table, the improvement comprismg:
spring loaded, rail-follower catching means, said catching means including:
a longitudinally extending catch body;
a first unitary tongue element at one end of said catch body and extending generally perpendicularly therefrom;
a first slot in said catch body for engaging said railfollower, said first slot being located inward of said first tongue and adjacent thereto;
a second unitary tongue element, inward of said first slot and adjacent thereto;
a second slot in said catch body for engaging said rail follower, said second slot being located inward of said second tongue element and adjacent thereto: and
a catch support pin aperture, inward of said second slot;
a pair of catch supporting bracket means each formed integrally of a respective flange on said rail and extending generally perpendicularly thereto: a bracket body on each of said catch supporting bracket means;
slot means in each bracket body for securing a rail follower cooperatively with said second slot of said catch body;
a catch support pin aperture in each bracket body;
a catch support pin extending through the support pin apertures of said catch body and said catch support bracket bodies;
spring means, cooperative with said catching means, said bracket means and said catch support pin, for urging said first tongue element of said catch body toward the channel of said rail;
and means for distributing locking impact force along the length of the rail follower;
said impact-distributing means comprising ear means formed integrally of each bracket body adjacent to the bracket slot means thereof and extending from said bracket body in a direction transverse to the direction of movement of said rail follower;
the dimension of said ear means in said transverse direction being relatively large compared to the thickness of said bracket body at said slot.