WO2010146600A1

WO2010146600A1 - Folding utility board

Info

Publication number: WO2010146600A1
Application number: PCT/IN2010/000401
Authority: WO
Inventors: Shreeyash Patankar; Rohit Pitale
Original assignee: Individual
Current assignee: Individual
Priority date: 2009-06-15
Filing date: 2010-06-14
Publication date: 2010-12-23
Anticipated expiration: 2011-12-15

Abstract

A collapsable table comprises of a plurality of planks (2), supported by a pair of linkages (1), a support structure (4) and a locking mechanism (3), where the planks (2) and linkage (1) can be collapsed into a compact package which is portable and easily stored.

Description

FOLDING UTILITY BOARD

FIELD OF INVENTION:

This invention relates to collapsible furniture cum utility tables. Aspects of this invention also relate to mechanism used for retractable steps, generally used in vehicles.

BACKGROUND OF THE INVENTION:

Various collapsible work tables are known in the art.

U.S. Pat. No. 4392437 constitutes different constructions of multi-paneled rectangular folding tabletops supported by a pair of sub-frames with foldable legs and which can be interlocked to form a single supporting frame. The construction allows for a tabletop made of thin, lightweight material while still retaining rigidity and strength, but it doesn't assure extreme compactness when folded.

U.S. Pat. No. 1618327 relates to a table which can be folded into a bundle of very small dimensions for transportation and storage and can be quickly opened and used as a table with sufficient rigidity and support from attached foldable legs and frame structure. The linkage or mechanism used does not allow adding more no. of segments for having longer table surfaces while still retaining the compactness.

U.S. Pat. No. 2654647 relates to a casual utility or a game table with foldable tabletop and foldable legs, having segmental sections which are connected to each other, hingedly at their edges. This allows the segments of the tabletop to be folded in superposed relation in the collapsed condition of the table, thus to cause the folded table to occupy a relatively small area.

The above inventions have the limitation of not having a totally smooth surface free of ridges and hence don't serve the purpose of a game table or a drawing table where a completely smooth plain surface, which is free of ridges or obstacles, is inevitable.

The constructions of U.S. Pat. No. 2654647 and U.S. Pat. No. 4392437 allow adding more no. of sections or segments to increase the open surface area to closed surface area ratio, although in a complicated manner. U.S. Pat. No. 3005670 shows a construction of a collapsible table keeping its usable surface free of ridges or slight differentiations in smoothness. But it has a quite a complex construction with a lot of parts and complicated manufacturing and also doesn't have the flexibility of adding more no. of parts while retaining the compactness, for larger surface area requirements.

U.S. Pat. No. 3884159 shows a foldable table with a series of parallel slats connected together by transverse pieces of non-rigid material allowing the slats to be collapsed onto each other when the table is folded. A diagonal cross-support is provided for supporting the slats when the table is open. Due to the flexible material used to connect the slats together, the rigidity provided isn't substantial enough for non- casual or specific purposes like sports or drawing where smoothness is also an important requirement.

U.S. Pat. Nos. 2575615, 3462170, 3807757, 4623160 and 5039119 describe collapsible and extensible staircase structures, used generally in vehicles for ingress and egress, having the tread plates of the steps rigidly mounted along the length of and between opposite pairs of parallel links of two spaced-apart lazy-tongs assemblies.

The mechanism doesn't allow the linkages or the tread plates to become co-planar. This limits the usage of the staircases to be converted into a bridge or ramp for access between places at same levels and the mechanism used is not capable of providing flat surfaces when expanded.

It is clear from the above description and examples that despite the availability of a number of foldable/collapsible tables/structures, there still remains a need for an improved collapsible work table that has the combined advantages of highly compact one-on-one stacking of the segments which on opening form a smooth planar rigid surface and has flexibility in the no. of segments making the top surface depending upon the surface area requirement, and is less expensive to manufacture

SUMMARY OF THE INVENTION:

The present invention tends to provide a foldable table to mitigate or obviate the aforementioned problems. Inversions of the lazy-tongs or the scissors mechanism have been employed for achieving extendability and retractability. The present invention allows for the required flexibility, compactness and smoothness lacking in above mentioned art.

The main object of the present invention is to provide a table or a utility board having sufficient rigidity and which may be quickly erected for use and collapsed for transportation and storage.

Another object of the present invention to provide a foldable tabletop or a utility board employing a mechanism, with planks supported by lazy tongs linkages on their ends, wherein contraction of the lazy tongs linkage results in an extremely compact arrangement with the planks piled up and having surface contact with adjacent planks, and expansion of the linkage results in the planks becoming coplanar, touching each other end-to-end, forming a continuous surface which is constructed to be free of ridges or slight differentiations in smoothness of its useable surface.

Yet another object of the invention is to provide a table or a utility board which is extremely simple in terms of design, inexpensive to manufacture and depending on the required area of the usable surface, multiple planks can be added without affecting the effectiveness of the mechanism, with the folding table being relatively

Another object of this invention is the provision of a table of the type that will occupy a space, when folded, no greater in depth than the combined thicknesses of the several table sections, and negligibly greater in breadth than the area of a single section.

Briefly, and in general terms, the present invention provides for an improved, collapsible table with a collapsible tabletop and a plurality of foldable legs. The tabletop comprises a series of planks supported by a pair of modified lazy tongs linkages on each side, such that the planks form a flat continuous surface when the linkages are expanded and the planks get piled up once the linkages are contracted, forming an extremely compact arrangement. A locking mechanism on the tabletop, locking relative motion between the movable parts of the tabletop, makes the assembly rigid in the working position and handles at each ends provided to hold the collapsed table in the closed condition. The collapsible table provides for an expandable and contractible mechanism employing the lazy-tongs linkage to rigidly support the planks and to transfer motion from one plank to another, and thereby enable the convenient unfolding and folding of the series of planks with only one input motion required at one of the extreme links of the lazy tongs linkages

In a preferred embodiment, the foldable legs are housed in the surface of the tabletop to reduce the space required for storage, and the locking mechanism extends between two adjacent planks at one end of the table top locking them together to make the tabletop rigid in the working position.

The modified lazy tongs illustrated in this invention can be used to replace most conventional lazy tongs, especially where a larger ratio between the expanded and contracted lengths is required.

The expandable and contractible mechanism, comprising a series of similar planks supported by a pair of modified lazy tongs linkages on each side, such that the planks form a flat continuous surface when the linkages are expanded and the planks get piled up once the linkages are contracted, can be utilized in several applications like collapsible staircases generally used in vehicles and hospital beds, or window blinds, collapsible shutters, display equipment and other applications requiring such functionality.

Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS:

FIG.l is a perspective view of the contraption in the working condition in accordance with the present invention.

FIG.2 is a perspective view of the invention in the working condition with the support structure housed in the first plank.

FIG.3 is a perspective view of the table being collapsed.

FIG.4 is a perspective view of the table in the collapsed condition.

FIG.5 is a plane view illustrating the collapsing condition of the table.

FIG.5a is a superimposition view of the invention in different positions.

FIG.6 is a plane view of the collapsed condition.

FIG.7 is a cross-sectional view taken along lines 2-2 in FIG.2

FIG.8 is a cross-sectional broken view taken along lines 1-1 in FIG.2

FIG.9 is a perspective view of the first plank

FIG.10 is a perspective view of the second plank

PARTS DEPICTED IN THE FIGURES:

I. Linkage mechanism

II. First link

III. First hole of the first link

112. Center hole of the first link

113. Second hole of the first link 12. Second link

121. First hole of the second link

122. Center hole of the second link 123. Second hole of the second link

13. Third link

131. First hole of the third link

132. Center hole of the third link

133. Second hole of the third link

14. Pivot axle between the first link and the handle

15. Pivot axle between the first link and the first plank

16. Pivot axle between the first link and the second link

17. Pivot axle between the second link and the third link

18. Pivot axle between the first plank and the third link

19. Pivot axle between the third link and the third plank

100. Coupling screw between the second plank and part 17

101. Coupling screw between the second link and part 17

103. Hole in second plank for the coupling screw 100

104. Hole in second link for the coupling screw 101

105. Pivot axle made by the locking mechanism with the first plank

106. Pivot axle made by the bolt with the first plank 110. Spacer

2. Planks 21. First plank

211. Recess in the first plank

212. End hole in the first plank 213 .Center hole of the first plank 214. Through-hole of the first plank

215. Touching face between two planks

22. Second plank

221. Blind hole of the second plank

222. Center hole of the second plank

223. Plank 2 coupling hole

23. Third plank

231. End hole of the third plank

232. Second hole of the third plank

233. Center hole of the third plank

3. Locking mechanism

31. Eyebolt

311. Eyebolt shoulder

312. Eyebolt eye

32. Sleeve

33. Cover

331. Cover shoulder

34. Spring

4. Support structure

41. Support structure beam

42. Support structure end

43. Washer

44. Bolt 5. Handle

51. Handle end

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT:

The utility table or board according to the invention comprises a linkage mechanism supporting a plurality of planks and controlling motion transfer between the planks. The linkage mechanism comprises of two parallel running integrated modified lazy- tongs linkages. The expansion of and contraction of the lazy tongs linkages leads to the unfolding and folding of the utility table or board respectively.

Referring to Fig.3, 4, 5 and 6 the linkage mechanism comprises of a plurality of first links 11, second links 12 and third links 13, and planks 2. Each of the first links 11 includes a first end 111 and a second end 113. Each of the second links 12 includes a first end 121 and a second end 123. Each of the third links 13 includes a first end 131 and a second end 133.

The second end 113 of the first link 11 and the first end 121 of the second link 12 form a pivot axle 16. The center hole 122 of the second link 12 and the center hole 132 of the third link 13 form a pivot axle 17. The second end 212 of the first plank 21 and the first end 131 of the third link 13 form a pivot axle 18. As can be seen in Fig. 3 and in Fig. 5, the links 11, 12, 13 and the plank 21 are so positioned as to lie in different planes parallel to each other, and so the pivot axles 16 and 18 also Ue in different planes and do not coincide on becoming co-axial as seen in Fig. 1 and 2. The second end 133 of the third link 13 and the first end 231 of the third plank 23 form a pivot axle 19. The second end 123 of the second link 12 and the first end 111 of the first link 11 to follow form a pivot axle 16. The pivot axles 16 and 19 lie in different planes and do not coincide on becoming co-axial. The pivot axles connecting the ends of two links and those connecting the handle and the link may be comprised of rivets, the head should be flushed with the surface of the link facing the surface of the connecting link such that the links can freely rotate about the central pivot axle without any hindrance from the head of the rivet. Fig. 7 illustrates the same. Fig. 5a illustrated the working of the mechanism. The first plank 21 comprises of a recess 211 with two transverse through holes 214 which run through the recess 211. It also comprises of a center tapped hole 213 and a blind hole at the end 212.

Referring to Fig.2 and 9 the first plank 21 is connected to the first link 11 through a pivot axle 15 formed by the center hole of the first link 112 and the center hole of the first plank 213. The second hole of the first plank 212 and first end of the third link 131 form a pivot axle 18. This pivot axle 18 is preferably a screw with its head lodged in the second hole of the first plank 213. The head of the screws should also be flushed with the link surface as explained with the case of the rivet. The pivot axles mentioned in the embodiment can be made integral with the links or planks if required and the fasteners described may be replaced by rivets in appropriate circumstances or by other fasteners and the same is true of the rivet fasteners.

Referring to Fig.3, 4 and 10 second plank 22 and the second link 12 are connected rigidly. Fig.7 is a cross-sectional view taken along lines 2-2 shown in Fig.2. The rigid connection is achieved by coupling the second plank with the pivot axle 17, the second link is coupled to the pivot axle using a screw coupling 101. The third link 13 and the second link 12 are connected rotatably at the center portion in the crossed condition forms a pivot axle 17 as shown in Fig 3. This pivot axle is formed by the rigid connection between the second link 12 and the second plank 22. The third links 13 thus lay between the second plank 22 and the second link 12.

The holes incorporated in the second plank 2 for the coupling screw 103 are tapped holes as shown in Fig. 7; these are preferably made from underneath the working surface so as not to hinder the flat and continuous nature of the working surface. Otherwise, the head of the coupling screw 100 should be flushed with the working surface.

Referring to Fig.8 and 9, the plane of the end-to-end touching faces of the planks 215 make an obtuse angle with the working surface measured in the direction of allowable rotation. It helps to prevent any interference between the planks when the linkage is contracting and expanding, and to eliminate any gap between end-to-end touching faces of the adjacent planks, when the plank assembly is completely expanded. Also it is crucial in distributing the load to all planks and the locking mechanism 3 which constrains the assembly in the working condition.

Referring to Fig. 2 and 5 the third plank 23 comprises of the first holes 231, the second holes 232 and the center hole 233. The first hole and the second hole are the two extreme ends and the center hole is at the center portion of the plank. The second hole 133 of the third link 13 and the first hole 231 of the third plank 23 form a pivot axle 19.

A spacer 110 with is provided between the planks 2 and the first link 11. It is placed over the pivot axle 15. The spacer ensures a constant the distance between the linkage and the planks and also protects the threads of the pivot axle.

The first link 11 and the second link 12 rotate about the first pivot axle IS and the second pivot axle 17 in opposite rotational directions. The axes of the pivot axles are parallel to each other.

The handle 5 and the first links 11 are connected rotatably. The end of the handle 51 and the first end 111 of the first link 11 form a pivot axle 14.

Each of the lines, made by the end hole 212 and the center hole 213 of the first plank 21, and that made by the first end and second end of the second plank, and that made by the first end hole 231 and second end hole 232 of the third plank 23 make the same angle with the plane of the central pivot axles of the first plank, second plank and third plank.

Referring to Fig.3, 5, 7, 8, 9 and 10 the locking mechanism 3 is attached to the first plank 21. The view 1-1 of Fig.2 illustrates the cross-section of the locking mechanism. The locking mechanism comprises of a shaft 31, preferably an eyebolt with a shoulder 311, a sleeve 32, a spring 34 and a cover 33 with internal threads. An eyebolt is used to allow easy pulling of the locking mechanism to retract the cover from the blind hole of the second plank 211. This can be done by inserting a finger in the eye of the eyebolt 312 and pulling it away from the first plank 21. The locking mechanism is located inside the hole of the first plank 214 and also the blind hole of the second plank 211. The size of the hole in the first plank and that in the second plank are such that there is no gap between the cover and the mentioned holes. The locking mechanism runs between the first plank and second plank. The mechanism hence makes the whole contraption rigid in the working condition. The operation can be performed by pulling and releasing the shaft of the locking mechanism. The step formed over the shaft by the cover 33 constrains the spring between the step formed by the support structure and itself. The spring 34 lies in the space between the sleeve 32 and the inner surface of the hole in the first plank 214 and the hole in the second plank 221 in the working condition. The sleeve covers the shaft so as to lie between the inner space of the spring and over the shaft. The sleeve is constrained by the shoulder of the shaft 311 and the step at the end of the shaft 331. The step at the second end of the shaft is formed by a cover 33, with internal threads, attached to the shaft 31 releasably. The spring compresses as the eyebolt is pulled. The locking mechanism retracts to its original position as the spring retains its original condition.

Referring to Fig.l, 2, 4 and 9 the support structure 4 comprising of foldable legs or beams is connected to the first plank 11 rotatably. The end of the support beam 42 and the hole of the recess of the first plank 214 form a pivot axle 105. The pivot axle also forms the shaft of the locking mechanism 3. The beams of the support structure enclose themselves completely in the recess of the first plank 211 such that they lie between the plane of the working surface and the surface underneath the working structure. The end of the beam rests on the sleeve 32 of the locking mechanism. The beam is constrained within the recess and its motion is constrained to rotation about the pivot axle formed by the locking mechanism 105. The beam when rotated in the working condition is constrained by the inner surface of the recess of the first plank. The beams 41 of the other end of the contraption are preferably connected to the first plank via bolts 44. Washers 43 are preferably used between the bolts and the planks. Washers are also preferably used between the beams and the first plank. The washers provide the required spacing between the surface of the support structure beam 41 and the inner surface of the recess of first plank 21. The washers also provide friction to retain the beam in the recess of the first plank 211.

Referring to Fig. 1 and 2 in the working condition a flat and continuous surface is achieved, which is easily accessible from all four sides of the surface and thus can aptly be used as a collapsible table for outdoor operations.

It should be noted that the linkage mechanism according to the invention has potential uses other than a collapsible table with a substantial continuous and flat surface. Note in Fig. 3 for example, that when the planks make a right angle with the axis defined by the pivot axles 14, 15, and 16, the contraption can be used as collapsible steps. The first plank can be modified and attached to an elevated surface and opened to the floor for loading personnel onto the elevated surface.

Although this invention has been described with a certain degree of particularity, it is to be understood that the present disclosure has been made by way of example only and that numerous changes in the detailed construction and the combination and arrangement of parts may be resorted to without departing from the spirit and scope of the invention as hereinafter claimed.

Claims

What is claimed is:

I) A folding table comprising a plank assembly forming the tabletop comprising expandable and contractible support linkages comprising of atleast two parallel disposed unconventional lazy-tongs linkages that are spaced apart appearing as mirror images of each other, the basic unit of each of the said lazy-tongs linkage formed by four pivotally interconnected links, having its parallel links so constrained as to lie in different planes that are parallel to the planes of the said lazy-tongs linkages while the said lazy-tongs linkages are being expanded from a contracted position, thereby allowing the said four links to lie in the same plane, which is perpendicular to the plane of the said lazy-tongs linkages, when the said lazy-tongs linkages are completely expanded, a plurality of elongated planks extending between parallel pairs of corresponding links of the two said lazy-tongs linkages, the ends of the said planks coupled rigidly with the said pairs of corresponding links and parallel to the said pairs of corresponding links realizing an arrangement wherein the said planks assume a generally coplanar position when the said lazy-tongs linkages are expanded, a foldable support structure comprising legs, connected pivotally to the said tabletop, for supporting the said tabletop in the working condition, and the said legs, when folded, are housed completely into the surface of the tabletop, thus requiring no added storage space, with means to constrain the motion of the said legs in the folded and working condition, and means to lock the motion between any two relatively movable parts of the said plank assembly, like the motion between a pair of adjacent links of the said lazy- tongs linkages, or the motion between a link of the said lazy-tongs linkages and its adjacent plank, or the motion between two adjacent planks, once the said plank assembly is completely expanded.

2) The folding table according to claim 1 having the said plank assembly wherein the leftmost link, that is also the first link, of every basic unit of the lazy-tongs linkage on the right side, the corresponding rightmost link of every basic unit of the lazy-tongs linkage on the left side, and the corresponding plank rigidly coupled with the said links, are together replaced by a single plank interconnected in both the said basic units in the same way as the said replaced links. 3) The folding table according to claim 1 having the said plank assembly wherein each pair of adjacent planks having their surfaces, that face each other in the completely expanded position of the plank assembly, inclined in a direction, opposite to the direction of rotation of the said planks when the plank assembly is being contracted, said surfaces forming an angle with the plane in which the completely expanded plank assembly lies, the minimum value of the said angle depending upon the thickness and the widths of the said planks, and the said planks having widths so designed as to eliminate any gap between said surfaces of the said adjacent planks, when the said plank assembly is completely expanded.

4) The folding table according to claim 1 wherein the foldable legs are pivotally connected, to the end planks of the said plank assembly, at the four corners of the tabletop, a recess or a slot on the lower surface of each of the said planks, running along the length of the surface of the said planks, for housing the said legs when they are folded, the said legs assuming an obtuse angle with the said planks when the said legs are in the opened position wherein they are constrained from opening further by the corresponding lower edges of the recesses they are housed in.

5) The folding table according to claim 1 wherein the last said means includes a spring loaded locking shaft extending between two adjacent planks at atleast one of the two ends of the said plank assembly providing to lock the relative motion between the two said planks when the said tabletop is completely expanded.

6) An expandable and contractible utility board formed by a plank assembly comprising an expandable and contractible support linkage comprising atleast two parallel disposed unconventional lazy-tongs linkages that are spaced apart appearing as mirror images of each other, the basic unit of each of the said lazy-tongs linkage formed by four pivotally interconnected links, having its parallel links so constrained as to lie in different planes mat φe parallel to the planes of the said lazy-tongs linkages while the said lazy-tongs linkages are being expanded from a contracted position, thereby allowing the said four links to lie in the same plane, which is perpendicular to the plane of the said lazy-tongs linkages, when the said lazy-tongs linkages are completely expanded, a plurality of elongated planks extending between parallel pairs of corresponding links of the two said lazy-tongs linkages, the ends of the said planks coupled rigidly with the said pairs of corresponding links and parallel to the said pairs of corresponding links realizing an arrangement wherein the said planks assume a generally coplanar position when the said lazy-tongs linkages are expanded and optionally a means to lock the motion between any two relatively movable parts of the said plank assembly, like the motion between a pair of adjacent links of the said lazy- tongs linkages, or the motion between a link of the said lazy-tongs linkages and its adjacent plank, or the motion between two adjacent planks, once the said plank assembly is completely expanded.

7) The expandable and contracture utility board according to claim 6 having the said plank assembly wherein each pair of adjacent planks having their surfaces, that face each other in the completely expanded position of the plank assembly, inclined in a direction, opposite to the direction of rotation of the said planks when the plank assembly is being contracted, said surfaces forming an angle with the plane in which the completely expanded plank assembly lies the minimum value of the said angle depending upon the thickness and the widths of the said planks, and the said planks having widths so designed as to eliminate any gap between said surfaces of the said adjacent planks, when the said plank assembly is completely expanded.

8) The expandable and contractible utility board according to claim 6 wherein the last said means includes a spring loaded locking shaft extending between two adjacent planks at atleast one of the two ends of the said plank assembly providing to lock the relative motion between the two said planks when the said tabletop is completely expanded.

9) An unconventional lazy-tongs linkage, wherein the basic unit of the said lazy- tongs linkage formed by four pivotally interconnected links, has its parallel links so constrained as to he in different planes that are parallel to the plane of the said lazy- tongs linkage, while the said lazy-tongs linkage is being expanded from a contracted position, thereby allowing the said four links to lie in the same plane, that is perpendicular to the plane of the said lazy-tongs linkage, when the said lazy-tongs linkage is completely expanded.