US3280767A

US3280767A - Removable-shelving rack

Info

Publication number: US3280767A
Application number: US432265A
Authority: US
Inventors: Kahn Benjamin
Original assignee: THEODORE EQUIPMENT CORP
Current assignee: THEODORE EQUIPMENT CORP
Priority date: 1965-02-12
Filing date: 1965-02-12
Publication date: 1966-10-25
Anticipated expiration: 1983-10-25

Description

REMOVABLE-SHELVING RACK Filed Feb. l2, 1965 United States Patent O 3,280,767 REMOVABLE-SHELVING RACK Benjamin Kahn, New York, NSY., assignors to Theodore Equipment Corporation, Wood-Ridge, NJ., a corporation of New Jersey Filed Feb. 12, 1965, Ser. No. 432,265 Claims. (Cl. 10S-144) This invention relates to improvements in tiered corner-posted removable shelving racks of the heightadjustable, and knock-down shelf variety, and particularly to an improved corner securement construction for such slidably adjustable removable and reassembleable shelving.

Known shelving of the above type are characteristically of limited strength, rigidity and utility, and expensive; in that they embody in their corner constructions, cumbersome parts of inefficient complex design requiring the application of parts made under involved fabrication techniques and of costly high-strength expensive materials to withstand the high stresses to which such parts at the corner junctures are subject.

It is therefore one of the principal objects of my invention to provide a shelving rack of the subject character wherein the corners of the shelves are of novel design and construction; of few basically simple but direct acting parts of substantially symmetrical form and function, whereby an efficient, rigid corner-juncture of high parts-engaging power and stress-sustaining capacity is obtained.

Another object of the invention is the provision of a unitary, multiple-tiered corner-posted shelving rack 'wherein the shelves are firmly corner-engaged and positively supportable at preset, infinitely adjustable levels, and wherein, the shelves are individually, or all, removable and returnably replaceable to their preset levels.

A further object of the invention is the provision of a shelving unit of the above mentioned character wherein the separable shelves, initially at the factory, are quickly and easily set-up for subsequent assembly to prescribed levels and spacings in the field of use, and wherein, the separable shelves are quickly, positively and firmly lockable in factory set-up place and levels, by hand, without the use of any tools, at initial and subsequent field assembly, disassembly removal and replacement of the shelves.

A still further object of the invention is the provision of a corner-posted shelf unit of novel corner construction of high static load bearing capacity and of high dynamic rigidity; composed of few simple parts made of commercially available material and of such constructional form as to present at nished assembly, a neat appearance and of smooth exterior; inexpensive to manufacture; easy to clean; and simple, quick and easy to set up at the factory for shipment, assemble and manipulate in the field.

Other objects and advantages Will be pointed out and still others will appear in the following description of certain illustrated forms of the invention as shown in the accompanying drawing, in which:

FIG. 1 is a perspective view of a simple four cornerposted shelving rack embodying the invention.

FIG. 2 is a fragmentary sectional view of a shelf at its corner juncture, with its supporting post and associated parts seen as viewed along the arrows of the lines 2 2 of FIG. 1, with a part removed for purposes of clarity.

FIG. 3 is a sectional view of the corner fragment of the shelf parts as shown in FIG. 2 as viewed upwardly along the lines 3-3 of FIG. 1.

FIG. 4 is a horizontal sectional view taken along the lines 4-4 of FIG. 3, and as seen also along the lines 4-4 of FIG. l.

3,280,767 Patented Oct. 25, 1966 rice FIG. 5 is an enlarged fragmentary detail sectional view of certain parts in their locked engaging position.

FIG. 6 is an enlarged fragmentary detail of a slotted element shown in FIG. 5 and as seen along the lines 6 6 of FIG. 5.

FIG. 7 is a fragmentary plan view of a modified form of compound shelving embodying the invention.

FIG. 8 is a detail plan view of a certain group of parts employed in the form shown in F-IG. 7.

FIG. 9 is a view similar to FIG. 8 but of another group of parts employed in the form of the invention shown in FIG. 7.

FIG. 10 is a View similar to FIG. 3 but of a modified form of certain parts of the invention.

FIG. 11 is a view taken substantially along the lines 11-11 of FIG. 10 with a part removed and another shown in dot and dash lines for the purpose of clarity of delineation.

FIG. 12 is a view of a modified forrn of knob-nut used in the invention.

FIG. 13 is a modified form of sleeve member used in the invention.

Referring to FIGS. 1 to 6 illustrating one embodiment of the invention in the form of four corner posted tripletiered shelving rack of the stationary licor-supported type, the vertical rnetal posts generally designated as 10, are disposed at each of the vertically aligned corners of the metal shelves generally designated as 12.

The posts 10 are preferably provided with vertically adjustable feet 14 to accommodate, within a reasonably limited range, any elevational differences in floor level at the particular resting places of the feet. Metal sleevelike members generally indicated as 16, are adapted to encircle the posts at each of the corners of the shelves. These sleeve-like members 16 are preferably of complete cylindrical form but may be of open cylindrical C formation adapted to embrace the post circumferentially, more than half way around, as will become more fully apparent, later in this disclosure.

The sleeve-like members 16, in the instance shown, are preferably of metal pipe of suitable size but may be of any suitable commercially available seamless extruded or rolled and seamed or unseamed tubular stock. This kind of commercially available stock for the sleeve-like member 16 is essentially of straight hollow form having straight, unwavy and untapered walls and surfaces as distinguished from such surfaces of a molded, cast or forged sleeve-like members having inclined draft surfaces and wherein the walls are tapered and/ or wavy.

The posts 10 are also preferably made of commercially available pipe or tubing that have outer surfaces coaxially straight, unwavy and untapered, whereby such surfaces are particularly well adapted for good and extensive contractable engagement with the inside untapered surface of the sleeve-like members 16 for the attainment of extensive firm contact between these engaging parts, the desirability of which will be more fully explained hereinafter.

A conventional, commercially available, standard metal hex nut 18 of suitable size is secured, as by welding at 20, to the sleeve 22 of the sleeve-like member 16. Any other nut or threaded member and any other well known manner or means may be employed to provide the sleevelike member with a thread, such as by stakeing, or force fitting a threaded boss to the sleeve 22, or even by tapping the latter per se, providing however that the wall, at least at the threaded zone, is of sufficient thickness such as is seen in the sleeve member 16a of FIG. 13, to provide an ample number of threads as at 28a, FIG. 5, to resist the full strength reaction required to positively and firmly lock the sleeve-like member 16 upon the post 10 under the required manually-induced wrenching torque of an accordingly sized set-screw. In the assembly illustrated, and referring to FIG. 3, the nut 18 is located over a hole 24 in the sleeve 22. The hole is larger than the ouside diameter of the set-screw 26, which later is adapted to fit the internal threads 28a of the hex nut 18; the hole 24 permitting the passage of the front end of the set-screw therethrough to impingingly engage the post 10, thus putting the front end of the set-screw under compression. This set-screw is also of a commercially available variety and preferably of the headless, recessedsocket type adapted for threaded cooperation with threads 28 in an internally threaded knob-nut 34. This knob-nut shown in FIGS. 3 and 4 is of substantial size and knurled so as to be particularly adaptable for manual finger operation. The threads 28 are in a blind hole, the blind end of the threaded hole being covered by a bulge 35, making the knob-nut of the acorn nut variety. If required, and on occasion necessary, as will be seen hereinafter, the knob-nut employed may be one with a through hole as shown at 32, in FIG. 12, so as to render the recessed socket of the set-screw accessible by a suitable wrench, through this hole 32; yet retaining all of the total functions of the acorn type of knob-nut. The set-screw hex socket is adapted to be engaged by a conventional hex bar wrench indicated by dot and dash lines 33, in FIG. 3, when the acorn knob-nut is removed and when projectable through a through holed knob-nut as shown in FIG. l2 which on certain occasions is used instead of the closed acorn type shown. The acorn type knobnuts are preferred not only because they are easier to clean but also because they are less prone to unauthorized and harmful tampering innocently induced by mere exposure of the hex socket of the set-screw, as is possible in the through holed variety.

The shelves 12 are preferably made of sheet metal, in substantially identical oblong shapes, with vertically disposed apron-like doubled-over flanges generally designated as 36. These aprons extend along the longitudinal front and back edges of the shelves as at 38 and 40 respectively, and along the

transverse end edges

42 and 44, and disposed intermediately, end to end, with respect to the longitudinal flanges. Each of these flanges terminates vertically along the end of a 90 degree substantially arcuate cut-out in the horizontal surface of the shelf at each of the corners thereof. An edge 46 of a longitudinal ange and an edge 48 of a transverse flange comprise a coacting pair of abutments at the ends of each of the corner cut-outs 50. The controlling ends of these cutouts are substantially in the plane of the outer surface of the sleeve so that, upon engagement of the cooperating pair of

edges

46 and 48 with a particular sleeve-like member 16, these edges will lie in full close and vertical contact with and along the outer surface of the sleeve and at substantially 90 degrees apart. The horizontal arcuate edge of the cut-out 50 need not necessarily be in close contact with the sleeve inasmuch as such contact contributes little to the overall strength of the juncture as a whole, as will become apparent later.

A brace-like member 56, best seen in FIGS. 2 and 3, comprising a strip or bar of metal, is adapted to be secured to the adjacent

free ends

52 and 54 of the apron flanges by means of spot welding as at 6i), or the like. The points of attachment of this bar to the ends of the apron flanges is preferably as close to the

virtual edges

46 and 48 as good fabricating practice permits in order to reduce the moment arm of flexure to a minimum. Accordingly, the brace is bent as at 57 and 58, bringing the directional extension of the brace-like member off its diagonal direction and in al direction normal to the apron flanges, but closer to the

edges

46 and 48 thereof. In the main, these brace-like members are disposed at substantially 45 degrees with respect to their adjacent apron flanges and at a distance A from the center of their respective cut-out 50. This distance A is preferably minimum; to provide a minimal clearance distance B, in-

ward of the nut 18, FIG. 3, to avoid vertically intersecting interference at assembly along the middle of the diagonal portion of the brace-like member when the shelf is set upon the set-screws, prior to and after tightening by means of the finger knob-nut.

A slot 62 along the bottom edge 61 of the brace-like member 56, and preferably midway thereof, has vertical sides 65 adapted to flank the set-screw 26 when the shelf is in position at its intended level as shown, that is, substantially within the height of the sleeves already clamped to the posts. In this position the bottoms 64 of the slots are in substantial contact or in proximity of the top of the threads of their respective set-screws 26; such position being maintained by locking means and in a positive manner, to be described herebelow. With the knob-nuts 34 removed or backed off (unscrewed and retracted inwardly) from the set-screws in their factory set positions, any one or all of the shelves, each in turn, may be lifted up and out or as the case may be, in and down, to remove and disassemble or replace and assemble the shelves from the posts in a quick and easy manner. This feature is important where sanitary requirements necessitate frequent removal of the shelves for thorough scrubbing.

A countersink 66 on the inward face of the brace-like member 56 is provided in the zone at the root of the slots. This countersink recess extends down along the flanks 65 of the slots as best seen in FIG. 6. The center of the countersink is located substantially midway between the flanks 65 at a distance down from the bottom 64 of the slots substantially equal to one-half of the outside diameter of the set-screws 26. With a slot width equal to the diameter of the set-screw, the center of the countersink would coincide with the axis of the set-screw. However, inasmuch as unavoidable and even desirable liberal manufacturing tolerance must be accommodated, the slots 62 are of necessity wider than the diameter of the setscrews, thus permitting the acceptance of misaligned setscrews or misaligned slots or, misalignment between the axis of the set-screw and the center of the countersink. This precise alignment is essential and easily obtainable, as will be seen.

The forward face of the knob-nut 70 is provided with a spherical bulge 72 adapted to project into the contiguous recessed areas of the countersink along the bottom and sides of the slot when the knob-nut is advanced thereinto during tightening thereof.

This tightening action, by turning the knob-nut with the fingers at final assembly, may be modified in its clamping force effect by modifying the knurling 37 in its gripping friction at the periphery of the knob-nut, thus controlling the optimum torque to achieve lthe tightening at final assembly. In tightening by the knob-nut, the back end of the set-screw is put in tension and the sleeve is drawn to the shelf edges in their median direction C between them, and ina wedge-like manner, into and between the angularly disposed engageable edges 46 and `48 of the shelf aprons. At the beginning of this tightening, the bulge 72, if not impeded by misalignment is caused to enter the recess of the countersink 66, thus first making the shelf corner captive against uplift. Upon further tightening, any high corner, caused by the lack of -iatness of the shelf, is brought to level by the piloting action of the entry of the bulge 72 as it enters and advances into the conical countersink. Finally, the apron edges 46 and 48 are drawn forcefully against the sleeve under high mechanical advantage provided by the screw thread action of the knob-nut against the firmly wrench-embedded set-screw. The entire corner -assembly is thus locked up tight and in a positive manner as by the reaction to compression of the front end of the set-screw between the sleeve and the post and by the reaction to the tension at the back of the set-screw between the shelf edges and the sleeve as in the form of FIG. 3, or against the post as will be seen in the descrip- -tion of FIG. 10. In any case the set-screw is subject to two distinct forces along its axis, namely, compression at its front end and tension along its back end.

The term final assembly implies setting the shelves onto the posts, the latter already having thereon the sleeves which were preferably set in place by the wrench-tightened set-screws at the factory. The final assembly is preferably done without tools, and as explained, is accomplishable by simple finger-turning upon the knob-nuts. Should any objectionable misalignment become apparent during final assembly, its correction is not preempted. Upon the removal of the preferred acorn knob-nut and temporarily replacing it with a knob-nut having a through hole, the set-screw may be loosened with a wrench, and tightened up again in its adjusted, properly aligned position, whereafter, the acorn knob-nut is replaced. Misalignment in the vertical direction is self-accommodating by the flexible and yieldable nature of the particular corner of the shelf per se. Therefore, the only adjustment possibly required would be in a horizontal direction, as might occur in the set-screw projecting not in the middle of lthe slot 62, but toward one or the other of the flanking edges of the slot, as shown by the dot and dash

lines

63, or 63a. The sleeves 16 are preferably, but not necessarily, factory locked to the posts at pre-specified levels. Starting from the bottom 11, preferably removable equally spaced markings on the posts are preferably u-sed -at the factory to line up the sleeves to the desired prescribed levels, and, by means in responsible factory trained hands the setscrews lare longitudinally aligned and wrenched home with sufficient force necessary to carry the rated load on the shelves. Where adjustment in the field requires the loosening and subsequent re-tightening of the set-screws with a wrench of course, the effort required at loosening the factory wrenched set-screw serves inherently as to the effort required upon the wrench at re-tightening. The sleeves and the set-screws take the full download in friction and shear and the shelves need only be placed on the set-screws and need not necessarily be firmly locked in place to function effectively under such download. All that is safely required is to advance the knob-nut so that its bulge enters the countersink to prevent the shelf from any unintentional uplifting displacement.

Where however, side loads are encountered or injected in use by twisting, shifting and turning the rack or its load, as occurs in a mobile rack, with wheels instead of feet, in the hands of careless users in the field, or, as in a station-ary rack as illustrated, where the loads are dragged across the shelves creating side forces and sway that need to be resisted, the desirability of firm and strong wedge-like clamp tightening at the corners is readily apparent.

In the field at initial assembly of the shelves, and thereafter, under properly aligned conditions as above described, with the bulge 72 directed into the countersink recess 66, and at final finger tightening of the knob-nut 34, the spherical surface of the bulge 72 engages the conical surface along a circular line 74 along an arc of substantially 270 degrees around the slot 62. This line or zone of con-tact extends over the bottom of the slot and along. the anking side walls 65 thereof. Under such relationship of pressure contact the clamping forces are horizontally and laterally equally distributed, uniformly distributed symmetrically inboard to the opposingly adjacent `and cooperating pair of vertical apron edges 46 and 48. With the direction ofthe forces midway between these edges the sleeve is wedgewise engaged by the said edges in a self seating snug-like manner and drawn together under the high pressure inducible by the mechanical advantage afforded by threaded knob-nut upon the setscrew, whereby twisting and bending moments are firmly -taken yand transmitted among the preloaded parts with high resistance to their disp-lacement. Even under low preloaded circumstances achieved by very light tightening of the knob-nut, the shelf is positively locked against uplift and yet with high download capacity.

Where desirable as in light duty low rated shelving racks for light loads, an extremely narrow sleeve may be usefully employed. As shown in FIG. 10, such narrow sleeve is in the form of a ring 76. Here, the

edges

46 and 48 are recessed as at 78 to clear and be spaced from contact with the ring. At tightening of the set-screw 26, the ring is fixed to the post by compressive impingement of the front end of the set-screw. At tightening of the knobnut, tension along the back end of the set-screw takes place causing abutment of the shelf edges directly with the post 10 along parallel zones in vertically opposed pairs of apron edges as at and 82 of one apron edge and at 84 and 86 of the other apron edge `at 4righ-t angles to the first mentioned pair and thus forming a wedge-like seat against the post, in the same manner as described with respect to the shelf abutment against the sleeve.

The sleeve-like member may also be made perforate, or be provided with vertical slots to permit projections like the

edges

46 and 48 of the aprons to enter such slots and be in direct contactable engagement with the post through the sleeve-like member, with the same results acfiieved by the illustrated ring construction of FIGS. l0 an 11.

Where a C type sleeve is used, leaving one quadrant of the post exposed in the open portion of the C, coacting edges of aprons of proper length, one longer than the other may be usefully employed. Here, the longer and more extending edge is adapted to contact with the outer surface of the post while the shorter and less extensive `apron edge is at right angles to the first and is adapted to engage the outer surface of the sleeve. The clamping effects are substantially the same in principle as in the forms previously described.

Where it is desired to join together in coplanal contiguous fashion rack units of the character described at any given level where one end of a shelf abuts another or where two shelves abut end-to-end, such :as is illustrated in FIG. 7, where shelf corners share the same sleeve-like members, sleeve constructions having two or more set-screws such as shown in FIGS. 8 and 9 are employed.

At 10c, FIG. 7, the contiguous corners of the

shelves

40a and 40b have their support and connection on and with the sleeve 22C, FIG. 8, having two hex nuts 18e and 18f disposed at 90 degrees apart horizontally to engage the diagonal braces of the shelf corners as heretofore described, At such junctures as at 22d where four corners of shelves meet in a common planed contiguous cluster as at 10d, FIG. 7, these are readily supported and engaged in the manner previously described by a sleeve-like member 22d, FIG. 9. This quadruple type sleeve or ring as the case may be, is provided with four equally spaced

hex nuts

18g, 18h, 18j and 18k horizontally disposed and adapted to receive the respective set-:

screws

26g, 26h, 26j and 26k, for the purpose similar in functional principle to that above described. The free corners of the shelves 40e and 40d of the aforementioned shelves as seen in FIG. 7, are supported by Iapron clips 90, as are well known in the art of shelving racks.

Having thus described the invention in detail with respect to certain forms embodying the principle aspects thereof, it is understood that other modifications and variations may be had without departing the principles embraced in the illustrated constructions as set forth -in the following claims.

I claim:

1. In a shelving rack of the character described, a corner construction comprising the combination o-f a vertically disposed post, a sleeve-like member embracing said post, said sleeve-like member having a threaded hole therein horizontally disposed, a male screw member in said threaded hole adapted at its front end and in compression to impingingly engage the outer surface of said post and urge said sleeve-like member, against said post to x the vertical position of only said sleeve-like member upon said post, .said male screw member having wrenching `means at its back end, a shelf having corner edges adapted to engage the said sleeve-like member, a bracelike member on said shelf and diagonally disposed with respect to said shelf corner, and a nut-like member on the back end of said screw member adapted to engage said brace-like member and adapted -to apply tension upon the back end of .said screw member to press said shelf corner against said sleeve-like member.

2. In a shelving rack of the character described, a corner construction comprising the combination f a vertically d-isposed post, a sleeve-like member embracing said post, said sleeve-like member having a threaded hole therein horizontally disposed, a male screw member in said threaded hole adapted -to impingingly engage the outer surface of said post and urge said sleeve-like member, against said post to fix the vertical position of only said sleeve-like member upon said post, said male screw member having wrenching means :at its back end, a shelf having corner edges adapted to engage the said sleeve-like member, :a brace-like m-ember on sai-d shelf and diagonally disposed to said shelf corner, said brace-like member having a slot therein, the Walls of said slot adapted to flank said male screw member, and a nut-like member on said screw member adapted to engage said brace-like member along said anks of said slot to draw and clamp said sleeve-like member and said shelf corner together and against each other with substantially equalized forces therebetween them on either side of the male screw member.

3. In a shelving rack of the character described, a corner construction comprising the combination of a vertically disposed post, a sleeve-like member embracing said post, said sleeve-like member having a threaded hole therein horizontally disposed, .a male screw member in said threaded hole adapted to irnpingingly engage the outer surface of said post and urge said sleeve-like member, against said post to fix the vertical position of only said sleeve-like member upon said post, said male screw member having wrenching means at its back end, a shelf having spaced vertical Icorner edges adapted to engage the said sleeve-like member vertically, 'a brace-like member on said shelf and diagonally disposed to said shelf corner, said brace-like member having a vertically disposed slot subsequently midway horizontally therein, the walls of said .slot :adapted to flank said male screw member, and a nut-like member on said screw member adapted to engage said brace-l-ike member along said Hanks of said slot to draw and clamp said sleeve-like member and said shelf corner edges together and against each other with substantially equal forces therebetween them along the said edges on either side 0f the slot.

4. In a shelving rack of the character described, a corner construction comprising the combination -of a vert-ically disposed post, a sleeve-like member embracing said post, said sleeve-like member having a threaded hole therein horizontally disposed, a male screw member in said threaded hole adapted to impingingly engage the outer surface of said post and urge said sleeve-like member, against said post to fix the vertical position of said sleeve-like member upon said post, said male screw member arriving at a stationary home position rwhen said sleeve is in said xed position, a shelf having spaced corner edges adapted to engage said sleeve-like member on its outside and on either side of the center thereof, a brace-like member on said shelf diagonally disposed to said shelf corner edges, said brace-l-ike member having a vertically disposed slot substantially midway horizontally between the said corner edges of the shelf, the walls of said slot adapted to straddle said male screw member, and a threaded knob member 0n said male screw member adapted to engage said brace-like member along the Hanks of said slot to clamp said sleeve-like member and said shelf corner edges together, whereby said shelf is independently vertically removable from the assembly upon loosening of said knob member, without disturbing the above said positionings of the sleeve-like member and the male screw member.

5. In a shelving rack of the character described, a corner constr-uction comprising the combination of a vertically disposed post, a member embracing the post having a horizontally disposed female thread therein, a male screw member in said female thread adapted under compression at its front end to impingingly engage the outer surface of said post and urge said sleevelike member, against said post to X the vertical position of said post embracing member upon said post, said screw member adapted to project from said female thread at its back end, said male screw member having wrenching means at its back end, a shelf having horizontally spaced vertically disposed corner edges adapted to engage the said post on eithe. side of its center, a threaded knobnut adapted for linger manipulation on the projected portion of said male screw member, and a brace-like member diagonally disposed with respect to said shelf corner edges, said brace-like member adapted for engagement by said knob-nut member and disposed inward thereof, -whereby upon tightening of the said knob-nut the back end of the screw member is placed in tension and the said corner edges of the shelf are urged against the sloping surfaces of the post at the zones of contact with said edges.

References Cited by the Examiner UNITED STATES PATENTS 911,567 2/ 1909 Berkowitz 248-245 X 1,370,301 3/1921 Gertler 5-288 2,304,481 12/ 1942 Shannon 108-153 3,021,013 2/ 1962 Shiver 248-245 3,065,860 11/1962 Swanson 108-156 X 3,082,711 3/ 1963 Vetere 248-245 X 3,173,385 3/1965 Tucker 108-114 X 3,187,693 6/1965 Hamilton et al 211-148 FOREIGN PATENTS 1,249,430 11/ 1960 France.

OTHER REFERENCES Germ-an printed application 1,056,783, May 1959.

FRANK B. SHERRY, Primary Examiner.

JAMES T. MCCALL, FRANCIS K. ZUGEL, Examiners.

Claims

1. IN A SHELVING RACK OF THE CHARACTER DESCRIBED, A CORNER CONSTRUCTION COMPRISING THE COMBINATION OF A VERTICALLY DISPOSED POST, A SLEEVE-LIKE MEMBER EMBRACING SAID POST, SAID SLEEVE-LIKE MEMBER HAVING A THREADED HOLE THEREIN HORIZONTALLY DISPOSED, A MALE SCREW MEMBER IN SAID THREADED HOLE ADAPTED AT ITS FRONT END AND IN COMPRESSION TO IMPINGINGLY ENGAGE THE OUTER SURFACE OF SAID POST AND URGE SAID SLEEVE-LIKE MEMBER, AGAINST SAID POST TO FIX THE VERTICAL POSITION OF ONLY SAID SLEEVE-LIKE MEMBER UPON SAID POST, SAID MALE SCREW MEMBER HAVING WRENCHING MEANS AT ITS BACK END, A SHELF HAVING CORNER EDGES ADAPTED TO ENGAGE THE SAID SLEEVE-LIKE MEMBER, A BRACELIKE MEMBER ON SAID SHELF AND DIAGONALLY DISPOSED WITH RESPECT TO SAID SHELF CORNER, AND A NUT-LIKE MEMBER ON THE BACK END OF SAID SCREW MEMBER ADAPTED TO ENGAGE SAID BRACE-LIKE MEMBER AND ADAPTED TO APPLY TENSION UPON THE BACK END OF SAID SCREW MEMBER TO PRESS SAID SHELF CORNER AGAINST SAID SLEEVE-LIKE MEMBER.