US 3858529 A
A lazy susan or other multiple shelf device constructed for easy assembly and disassembly has an upper shelf supported above a lower one by rigid posts, each with a reduced extension at each end terminating in a cross key. The upper shelf has a slot-like opening through which the key at the top of the post is inserted, and the lower shelf a similar opening through which the key of the bottom of the post is inserted. When the post is then rotated the key at the top rides up an incline and the key at the bottom rides down an incline until both keys come to rest, and when all supports are in place the shelves are drawn tight against a shoulder on the post at the base of the reduced extension. For a lazy susan the lower shelf and a supporting base on which it rotates are pivotally connected with balls confined between them to provide a ball bearing support for the shelf on the base, the base and the lower shelf forming a single unit for packaging and storing.
Claims available in
Description (OCR text may contain errors)
United States Patent [191 Salladay 1 1 Jan. 7, 1975 KNOCK-DOWN MULTIPLE SHELF ASSEMBLY, PARTICULARLY A LAZY SUSAN  Inventor: Mack Salladay, Greentree Borough,
 Assignee: Action Industries, Inc., Cheswick,
 Filed: July 9, 1973 21 Appl. No.: 377,649
 US. Cl 108/103, 108/111, 211/163, 211/148  Int. Cl A47b 49/00  Field of Search 108/101, 94, 103, 139,
 References Cited UNITED STATES PATENTS 1,623,575 4/1927 Campbell 248/349 1,732,113 10/1929 Van Der Meer 1 248/349 2,373,722 4/1945 Von Opel 24/221 A 2,600,922 6/1952 Rodolfa 108/139 X 3,004,745 10/1961 Wilson 248/349 3,170,415 2/1965 Svilokos 108/53 X 3,236,389 2/1966 Murdock 108/101 X Derujinsky 108/139 Johnson 24/221 A  ABSTRACT A lazy susan or other multiple shelf device constructed for easy assembly and disassembly has an upper shelf supported above a lower one by rigid posts, each with a reduced extension at each end terminating in a cross key. The upper shelf has a slot-like opening through which the key at the top of the post is inserted, and the lower shelf a similar opening through which the key of the bottom of the post is inserted. When the post is then rotated the key at the top rides up an incline and the key at the bottom rides down an incline until both keys come to rest, and when all supports are in place the shelves are drawn tight against a shoulder on the post at the base of the reduced extension. For a lazy susan the lower shelf and a supporting base on which it rotates are pivotally connected with balls confined between them to provide a ball bearing support for the shelf on the base, the base and the lower shelf forming a single unit for packaging and storing.
4 Claims, 11 Drawing Figures Patented Jan. 7, 1975 3,858,529
3 Sheets-Sheet 1 Patented Jan. 7, 1975 3 Sheets-Sheet 2 KNOCK-DOWN MULTIPLE SHELF ASSEMBLY, PARTICULARLY A LAZY SUSAN This invention is for a multiple shelf structure which may be shipped or stored in a compact package, but easily put together without tools, and is particularly applicable to a lazy susan having a lower shelf or tray and supporting base connected for packing and storing as a single unit, and it will be so described in this application, without however excluding other multiple tray or shelf assemblies to which it is applicable.
Lazy susans are commonly made with two or more shelves, one spaced above the other, and the lowermost shelf is pivotally carried on a base so that it and the shelf or shelves above it rotate freely as a single unit. When it is assembled for use, a lazy susan is quite bulky and requires considerable space for storage and a large package for shipment. Consequently they are usually shipped knocked down or disassembled in compact packages to be assembled by the purchaser. Often, too, the purchaser may desire to use the device only on particular occasions and may find it convenient to take apart and store for the next occasion. Less expensive ones, such as are now offered for sale in drug stores, discount houses, chain stores, etc. are generally made of plastic and it is to such plastic articles that this invention is particularly applicable.
SHORT DESCRIPTION OF THIS INVENTION A lazy susan has a wheel-like base with a center portion and a rim which is of narrow channel section with transverse partitions extending crosswise of the channel, dividing it into sections. A single ball, such as a ball bearing ball, is placed in each or several of the sections. The lower shelf which is circular and of greater diameter than the base is held on the base by a pivoted connection and the flat under surface of this shelf rests on the balls. With this assembly the base and the lower shelf combined constitute a single unit with the balls confined between them and one which may be packaged and require no assembly by the customer. The lower shelf, being of larger diameter than the base, projects beyond the base and has a rim portion with an annular flange projecting above and below the plane of the lower shelf. The upper shelf is a circular flat disk generally similar to the lower one.
The upper shelf is held in fixed spaced relation to the lower one by three or more rigid posts extending between the rim portion of the lower shelf and the rim portion of the upper shelf. These posts are preferably of non-circular section with a reduced extension at each end so that there is a shoulder at each end of the post surrounding this small diameter extension. Each such extension terminates in a key element spaced by the neck longitudinally away from the shoulder. The lower shelf has a well, one for each post, into which the lower end of the post is received, and there is a partition in the well in which there is a slot through which the key element and the extension may pass, but the shoulder at the lower end of the post abuts against the top edge of the well. Each partition has inclined surfaces over which the key rides when the post is turned, the inclines terminating in flat surfaces on which the key extensions rest, clamping the bottom edge of the well between the shoulder of the post and the key. The top of the post is a duplicate of the bottom and the upper shelf has a well on the under surface which is a mirror image of the one on the upper surface of the bottom shelf. The key at the top of the post passes through the key slot in the partition of the well in the upper shelf or tray and engages inclined camming surfaces above said partition similar to those below the partition in the respective wells of the bottom tray. In this way the upper shelf is firmly clamped to the top of each post. As a matter of fact the keys at the top and bottom ofeach post and the key slots in the wells of the upper and lower shelves are so oriented that the post has its upper and lower ends passed through the key slots of the upper and lower shelves at the same time and their respective key extensions ride the inclined surfaces of the upper and lower shelves at the same time so that each post is inserted and turned through a slight arc to unite the upper and lower shelves together with only a single twist of the posts. one after another. The operation is, of course, repeated for each post. After once being assembled the parts will remain together with the top shelf supported through these posts on the bottom one with no screws, bolts or metal fastening of any kind being required.
The invention may be more fully understood by reference to the accompanying drawings in which:
FIG. 1 is an assembled view of a lazy susan embodying the invention;
FIG. 2 is a fragmentary plan view on a larger scale than FIG. 1 of the base member of the assembly;
FIG. 3 is a vertical section through the part shown in FIG. 2 in the plane of line III-lll of FIG. 2;
FIG. 4 is a top plan view of a portion of an upper shelf;
FIG. 5 is a similar view of a top plan view of a lower shelf which is substantially a mirror image of the bottom of the upper shelf;
FIG. 6 is a side elevation of one of the supporting posts;
FIG. 7 is a transverse section through the post of FIG. 6 in the plane of line VllVlI of FIG. 6;
FIG. 8 is an enlarged end view of a supporting post with two key extensions;
FIG. 9 is a fragmentary side elevation partly in section of the assembled lazy susan;
FIG. 10 is a plan view on a larger scale of one of the post connections shown in FIG. 4 with which the terminal of FIG. 8 cooperates; and
FIG. 11 is a vertical transverse section in the plane of line Xl-XI of FIG. 10.
In the drawings the lazy susan shown in FIG. 1 has an upper shelf or tray 2, a lower shelf or tray 3, a plurality, typically three equidistantly spaced supporting posts 4 for mounting the upper shelf or tray 2 on the lower one. The lower one is pivotally mounted on a base 5.
Referring particularly to FIGS. 2 and 3, the base 5 is a wheel-like circular disk with a center portion 5a, spokes 5b and a rim 5c of H section having an outer sidewall and an inner sidewall with a continuous cross web forming a channel 5d in the top of the rim, and there are a plurality of partitions 5e extending transversely across the channel at spaced intervals, preferably equally spaced so that the channel is divided peripherally into arcuate compartments. There is a hard round ball 6 in each of these compartments, there preferably being steel ball bearing balls, and the transverse partitions 5e keep each ball confined to a limited arc of travel so that they may never become bunched together.
The lower tray or shelf 3 has a flat main central area 3a with a peripheral flange 3b that extends both above and below the plane of the flat central area. The center of the tray is formed with a spacer 7 depending therefrom which passes through a central opening in the base member. Below thisspacer there is a washer 8 and an extension 9 of the spacer passes through the washer and is riveted over and thus holds the base as tightly against the bottom of the lower tray as permitted by the spacer 7 and contact with the under surface of the tray with the balls 6. This arrangement enables the lower tray to rotate on the base, but the lower tray and the base together along with the balls comprises'a unit assembly for packaging or storing and the balls cannot come out.
It will be noted that the diameter of the tray 3 is larger than the diameter of the base, so that the posts 4 are located out at the peripheral margin area of the lower tray and are clear of the base when the tray rotates relative to the base, as hereinafter appears, and as shown in the drawings, the base holds the lower shelf at a level where the lower ends of the posts and the ad jacent portions of the lower shelf are all above the plane of the bottom of the base so as to avoid rubbing on any surface on which the base is set'when the device is being used.
The posts 4 comprise a central column portion 4a, preferably of non-circular cross-section so as to be easily gripped and rotated by ones hand, as hereinafter described. As here shown, it is of uniform cruciform shape with a central area with four ribs 412 extending lengthwise thereof. Near each end the ribs are cutaway v to provide a short circular extension or neck 4c. At the outer end of each neck all four or only two of the original rib portions are retained, but their length in a radial direction is reduced. In the present drawing there are two such opposed extensions 42, but as above indicated there could be four of them. They are in axial alignment with but extend radially less far from the central axis of the post than do the ribs. This post as here shown then has at each end a reduced extension or neck 40, a key portion with opposed radial extensions 4e at the outer end of the neck, and a flat shoulder or end portion 4f from which the neck extends.
The upper tray or shelf 2 is in most respects the same as the lower one, but turned over relative to the lower one so that their confronting surfaces are mirror images of each other. The upper shelf 2, like the lower one, has a peripheral flange 2b that projects further below the plane of the main flat central area 2a of the shelf than it does above.
Each of the shelves 2 and 3 is formed with an integral circular wall portion 10 projecting below the plane of the shelf or tray on which it is formed, and extending above the plane of the tray only on the lower tray. This wall is so close to the edge of the disk that, as seen in FIG. 10, it is partly integral with the peripheral flange 2b or 3b, as the case may be, of the tray. Inside this wall 10 there is a transverse partition element 11, the maximum thickness of which is slightly greater than the thickness of the neck 40 on the end of the post. This partition has an opening or key slot 12 therethrough just large enough and of the shape required for the key portion at the outer end of the neck at each end of the post to pass.
As best seen in FIG. 11, the distal surfaces of the respective partitions ll, as opposed to the confronting surfaces, are formed with two inclined cams or surfaces 13, one leading from each end of the key slot toward the other, and terminating intermediate its arcuate length is a flat or level surface 13a.
This arrangement is such that when the upper tray is tobe assembledon the lower one, the user initially holds one tray above the other with the circular wall portions 10 of one approximately positioned over those of the other. Grasping one of the posts intermediate its ends, he inserts the key at one end in the well in the top of the bottom plate. passing the'key through the key slot, and inserts the upper end of the post into the bottom of the well in the upper shelf with its key passing through the key slot 12 of the upper shelf. He then twists the posts, so that the key extensions 40 ride up the cam surfaces 13 of both wells at the same time until these key extensions rest on the flat surfaces 13a of the respective trays, at the same time drawing the flat end portions 4f of the posts tight against the confronting end surfaces of the circular walls or wells 10 to firmly hold the two trays in spaced parallel planes. After inserting the first post the others are similarly inserted and turned. All of this can be done much more quickly than it can be here explained, and without tools, metal bolts or nuts or any threaded fastenings. To remove the top shelf, the posts are merely turned in the opposite direction to align the key extensions with their respective key slots.
The respective trays, the posts and the base are all preferably formed of plastic by injection molding, and even the space and rivet on the underside of the lower tray are molded integral with the tray with the riveting being done after assembly of the base and the lower tray.
1. A knock-down multiple shelf assembly having a lower shelf and an upper shelf and a plurality of spaced rigid posts extending between the two shelves wherein:
a. each post has a central column portion of uniform transverse section terminating in a shoulder at each end with an axial neck extending centrally from the shoulder, and a key at the outer end of the neck at each end of the post, the key having at least two oppositely extending key extensions thereon the radial length of which is greater than the diameter of the neck but less than the maximum diameter of the shoulder,
b. the upper and lower shelves having vertically aligned key slots therethrough of a contour and size for the key extensions at opposite ends of the posts to pass through but through which the shoulder ends of the posts cannot pass, the distal surface of the upper and lower trays having inclined cam surfaces extending arcuately about the key slots so arranged that when'the key extensions at opposite ends of a post are passed through aligned key slots in the upper and lower shelves and the post rotated through a limited are, any looseness is taken up and the respective shelves are clamped against the respective shouldered ends of the posts and so held by the key extensions bearing against the cam surfaces, each shelf having a well-forming wall around each key slot with a partition between the top and bottom of the well, the key slot and the surrounding inclined surfaces being provided by said partition, the key slots passing through the partition with the inclined surfaces being formed on the upper surface of the partitions on the upper shelf and the lower inclined surfaces on the lower surface of the partitions of the lower shelf, the partitions being so located in the wells that the ends of the posts when the assembly is completed are entirely within the respective wells at the top side of the upper shelf and the under side of the lower shelf.
2. A multiple shelf assembly as defined in claim 1 in which the column portions of the posts are non-circular to enable them to be better grasped for turning.
3. A multiple shelf assembly as defined in claim 1 in which said inclined cam surfaces each terminate in a level surface at the higher end of the incline to hold the posts against accidental rotation.
4. A multiple shelf assembly as defined in claim 1 in which the assembly is a lazy susan and shelves are circular and the posts are arranged at spaced intervals around the peripheral margins of the shelves only, the lower shelf being pivotally supported for rotation on a base of less diameter than the shelf whereby the lower ends of the posts are clear of the base when the shelves rotate on the base and of a thickness such that wellforming walls on the under side of the lower shelf are at a level where they are above the plane of the bottom of the base.