US3859930A - Tiltable tray with pivotally mounted legs having extensible feet - Google Patents

Abstract

A tray structure with legs for supporting a platform selectively at one of two heights above a planar surface, and at a selected inclination relative to the planar surface. Two long pivotally mounted legs are provided which are hollow and receive extensible feet. When the feet are retracted, the long legs serve to support the platform horizontally. When the feet are extended, they serve to support the platform in an attitude tilted from the horizontal. Latching mechanisms are provided for locking the long legs and feet in their extended and retracted positions. In the preferred embodiment, short legs are provided which serve the dual function of supporting the tray when the long legs are retracted, and locking the long legs in position when they are extended.

Description

United States Patent Sherwin 1 Jan. 14, 1975 [54] TILTABLE TRAY WITH PIVOTALLY 2,293,188 8/1942 Brice 248/1885 MOUNTED LEGS HAVING EXTENSIBLE 2,472,962 1/1949 Shufhn 108/131 FEET 2,485,178 10/1949 Welnkauf 108/132 2,580,126 12/1951 Randolph 108/131 [76] Inventor: Peter G. Sherwin, 1450 Cordova 2,755,152 7/1956 Calgy 108/1 Ave., Lakewood, 01110 44107 2,760,837 8/1956 Wade 108/129 [22] F]d M 29 1973 2,978,012 4/1961 Norseen 108/116 1e ar. [21] APPL No: 346,046 Primary Examiner-C asmir A. Nunberg R lated U S Application D t Attorney, Agent, or Fzrm-Watts, Hoffmann, Flsher &

e a a Heinke C0. [63] Continuation-impart of Ser. No. 238,787, March 28,

1972, abandoned, which is a continuation-in-part of [57] ABSTRACT 1971 abandoned A tray structure with legs for supporting a platform selectively at one of two heights above aplanar surg 2%? face, and at a selected inclination relative to the pla- [58] Fieid {08/1 6 116 nar surface. Two long pivotally mounted legs are pro-T 134 5 vided which are hollow and receive extensible feet. 153 159 6 5 3 When the feet are retracted, the long legs serve to 2:18/397 6 support the platform horizontally. When the feet are 2 1 1 l extended, they serve to support the platform in an atti- [56] Referen es Cited tude tilted from the horizontal. Latching mechanisms c are provided for locking the long legs and feet in their UNITED STATES PATENTS extended and retracted positions. In the preferred em- 99,608 2/1870 Spencer 108/129 bodiment, short legs are provided which serve the dual 157,753 12/1874 HildreIhW 243/398 function of supporting the tray when the long legs are $53 g retracted, and locking the long legs in position when 1 ym n... 1,855,219 4/1932 Brownell... 248/396 they are extended 1,924,945 8/1933 Klotz 108/1 15 Claims, 29 Drawing Figures (?0 K30 (26 (/2 271 Elx ?l\ PATENTED 3.859.930

SHEET 10F 6 INVENTOIE) 2 SHE/2 N F 3 PETE 6 Wm, We m 52m 1 4 TTOP/VE Y5.

TILTABLE TRAY WITH PIVOTALLY MOUNTED LEGS HAVING EXTENSIBLE FEET CROSS-REFERENCE TO RELATED APPLICATION The present application is a continuation-in-part of applicationSer. No. 238,787, filed Mar. 28, 1972, now abandoned, which was a continuation-in-part of application Ser. No. l3l,855, filed Apr. 7, 1971, now abandoned.

BACKGROUND OF THE INVENTION l. Field of the Invention The present invention relates generally to horizontally supported tiltable planar surfaces, and more particularly to a tiltable tray with pivotally mounted legs having extensible feet.

2. Prior Art Platforms which are tiltably mounted on various leg structures are well known. Platforms having legs which arepivotally mounted to fold beneath the platform are also well known. It is frequently desirable to provide a platform which includes both of these features, whereby the platform can be tilted relative to the surface above which it is supported, while the legs may also fold beneath the platform for storage. In conjunction with bed trays, for instance, it is desirable to provide a collapsible tray having a platform which may be positioned horizontally for eating, and tilted for reading and writing.

Most such trays proposed by the prior art suffer from r at least three substantial drawbacks:

l. the movable connectors which provide for pivotal leg movement and tilting of the platform are normally combined to form a bi-directionally movable connection between the platform and the legs. Such a connection is difficult to form in an inexpensive and simple manner without a substantial loss of rigidity.

2. The legs are not ordinarily adapted to support the platform above a planar surface when they are folded beneath the platform. Hence, most such trays are not usable with the legs folded beneath the platform.

3. The tray is either not provided with a means for locking its movable components in both the extended and retracted positions, or the latching mechanisms provided for such purposes are of relatively complex design.

SUMMARY OF THE INVENTION The present invention overcomes the foregoing and other drawbacks of the prior art and provides a tiltable tray with pivotally mounted legs having extensible feet.

The tilting movement of the platform is provided by means of feet which are extensible along an arcuate path beyond bottom portions of the platform legs. The legs are hollow and telescopically receive the extensible feet. By this arrangement, the tilting of the platform is not controlled by means of a tiltable connection between the platform and the legs, but rather by a telescopic connection between the legs'and their extensible feet. Hence, a highly stable pivotal connection may be used between the legs and the platform to permit the legs to pivot smoothly beneath the platform.

Both the feet and the legs are provided with planar bottom portions adapted to support the platform above a horizontal surface. The planar bottom portions of the legs serve to support the platform horizontally above a horizontal surface. The planar bottom portions of the feet are extensible along an arcuate path beyond the planar bottom portions of the legs to support the platform in a tilted attitude above a horizontal surface.

In two of three disclosed embodiments the legs are provided with transversely extending projections which serve as short auxiliary legs to support the platform when the legs are folded to their retracted position. These auxiliary supports also serve as stops to limit the pivotal movement of the legs and to define their extended position. i

In the preferred embodiment, short auxiliary legs are pivotally mounted beneath the platform to support the tray when the long legs are folded beneath the platform. The short legs are provided with cam surfaces which are biased into engagement with the long legs. During movement of the long legs to their extended position, the short legs are cammed outwardly. Once the long legs reach their extended position, the short legs snap inwardly to lock the long legs in their extended position.

In two of the three disclosed embodiments, the legs are pivotally mounted beneath the platform in such a way as to be removable for cleaning and repair. In one embodiment, each of the legs is removable only when it alone is moved to the retracted position. With both legs moved to the retracted position, their bottom portions are so closely positioned as to prevent removal of either of the legs. In a second embodiment, the legs are held in place by spring biased collars which can be moved axially of their supporting projections to permit leg removal regardless of whether theleg is in its extended or retracted position.

In the preferred embodiment, a compact leg locking assembly is secured to the underside of the platform. A pair of release members are provided which, when moved in one direction will release the long legs from their retracted position, and when moved in the opposite directions will release the long legs from their extended position.

Another pair of latching mechanisms are interposed between the legs and the feet to releasably hold the feet in selected extended or retracted positions. In one embodiment, this foot locking mechanism comprises legcarried pins which are engageable with knotched surfaces on the feet. In the preferred embodiment, the foot locking mechanism comprises leg-carried pawls biased into engagement with knotched ratchet surfaces formed on the feet.

Accordingly, it is the principal object of the present invention to provide a novel and improved tiltable tray with pivotally mounted legs having extensible feet.

Other objects and a fuller understanding of the invention may be had by referring to the following description and claims taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings,

FIGS. 1-7 represent the preferred embodiment of the invention at the time of filing the referenced parent application,

FIGS. 8-19 represent the preferred embodiment at the time of filing the referencedabandoned continuation-in-part application, and FIGS. 20-28 represent the preferred embodiment at the time of filing the present continuation-in-part application.

I "FIG. 1 is 'a sectional elevational view of a tray constructed in accordance with one embodiment of the whereby the platform of the tray is supported substanvtially horizontally;

FIG. 5 is an'end elevational view of the tray of FIG.

' lwith the legs and feet' both in extended positions whereby the platform. is tilted from the horizontal;

FIG. 6 .isan enlarged end elevational view of a portionof the tray of FIG. 1 showing the lock means which is interposed between one of the legs and its extensible foot; i

FIG. 7 is an enlarged sectionalview as seen from the plane indicated by the lines 77 in FIG. 1, showing the pivotal connection between one ofgthe legs and, the platform whereby the legs are rendered removable from the, platform when in their retracted position;

FIG. 8 is aside elevational view of a second tray embodiment, the view being partially in cross section with the legs pivoted to their extended position;

FIG. 9 is-a bottom plan view of the tray of FIG. 8;

FIG. 10 is an enlarged-cross sectional view of a portion of thetray of FIG. 8 with the leg which is shown being pivoted to-its extended position;

FIG. 11 is across sectional view on the same scale as FIG. l0-with the leg-which is shown being pivoted to its retracted position; v

FIG. 12'is a cross sectional view as seen from the plane'indicated by the line 12-12in FIG. 8;

" FIG. 13 is an enlarged cross' sectional view as seen from the plane indicated by the line 13-13 in FIG. 10;

FIG. '14 is an enlarged cross sectional view of a portion of the tray'as seen from the plane indicated bythe line 14-14 in FIG. 8;

FIG. 15 is an enlarged'bottom plan view of a portion of the leg-lockingv assembly of the tray of FIG. 8, the view being partially broken away to illustrate detail;

FIG. 16 is an enlarged cross sectional view of a portion of FIG. 12 illustrating the ratchet latching mechanism interposed between one foot and its associated FIG. 17 is an enlarged view partiallyin cross section and illustrating the pivotal connection between one of the legs and the platform, the leg and platform being shownprior to assembly;

FIG. 18 is a view on the same scale as FIG-l7 and illustrating the leg and platform 'of FIGS. 17 in assembled -configuration;

FIG. 19 is a cross sectional view on the same scale as FIG. 17 as seen from the plane indicated by the line 19l9 in FIG. 17; I

FIG. 20 is a side elevationalview of the preferred'tray embodiment with the long tray legs pivoted to their retracted position portions-of the tray being broken away to illustrate detail of construction;

FIG. 21 is a bottom plan view of thetray of FIG. 20;

FIG. 22 is a cross sectional .view of the tray with the long tray legs pivotedto their extended position as seen their retracted position;

from a plane extending through. one. of the legs Ina manner similar to that of FIG..12;

FIG. 23 is an enlarged bottom plan view of a one corner region of the tray with the long tray legs pivoted to FIG. 24 is a cross sectional view on the same scale as FIG. 23 as seen'from the plane indicated by the line 24-24 in FIG. 23; v I v I FIG. 25 is a view similar to FIG. 23 but with the long tray legspivoted .to their extended position, as. seen from a plane extending throughthe long'tra'y legs;

FIG'. 26 is a cross sectional view on the same'scale as FIG. 25 as seen from the plane indicated by theline 26,- 26 in FIG. 25;

FIG. 27 is an enlarged, bottom plan viewofa portion of the tray with the-l0ng legs removed to better illustrate the details of construction of the leg locking mechanism; I

, FIG. 28 is a cross sectional view on'the same scale as FIG. 27,-.as seen'from the plane indicated by-the line 28-28 in FIG. 27, and I FIG. 29 is a cross sectional view onthe same scale as FIG.f23 as seen from the 29--29 in FIG. 23.

DESCRIPTION OF ONE EMBODIMENT Referring to FIG. 1, a tray-is indicated generally by shown in their retracted positions in FIGS. 1 and 2 and in their extended positions in FIG. 3.

I When intheir retracted position, the'legs are releasably locked beneath the platform by means of primary leg locks 18, 19. The primary leg locks 18, 19 compriseapertured projections 20, 21 which are integrally formed with the platform 1.1.Rotatable L-shapedlock elements 22, 23 are carried by "theapertured projections 20, 21. As best seen in FIG. 2, thelockelements 22, 23 areinovable between a locked position, shown in solid lines, wherein they underly and engage portions of thelegs 14, 15 to an unlocked position, shown in phantom, wherein'they are positioned beside and disengage thelegs 14,15.

The legs l4, 15 are releasably held in their extended position by means of secondary leg locks 24, 25. The

secondary leg lock 'structures 24, 25 comprise latcharms 26, 27. Thelatcharms 26, 27 have one pivotally mounted aboutprojections 28, 29 formed integrally with thelegs 14, 15. The other ends of thelatch arms 26, 27 releasablyengage a pair of dependingprojections 30, 31 formed integrally with the platform 11. As is best seen in FIG. 1, thelatchJarms 26, 27 rotate to a position wherein they are juxtaposed along thelegs 14, 15 permitting the legs to move to their retracted positions.

Thelegs 14, 15 have integrally formed supports 32,

33 and 34, 35. The supports serve a dual function. First, each of the supports includes aplanar bottom portion 36 which is adapted to support the .platformlll above a planar surface when thelegs 14, 15 are rotated plane indicated by the line to the retracted position of FIG. 1. Second, each of the supports includes aplanar end portion 37 which serves as a stop to limit the pivotal movement of the legs and to define the extended position of the legs. As is best seen in FIG. 3, theplanar end portions 37 engage theunderside 38 of the platform 11 when the legs are in their extended position.

Each of thelegs 14, is hollow and telescopically carries and extensible foot. The extensible feet are shown in dotted lines in FIG. 2 and are indicated generally by thenumerals 40, 41. Since thefeet 40, 41 are substantially identical with each other, only one of the foot and leg assemblies will be described.

Referring to FIGS. 4 and 5, theleg 14 is shown having its associatedfoot 40 respectively in retracted and extended positions. Thefoot 40 comprises a substantially circular segment including anarcuate side surface 42 which is disposed opposite anapex region 43. Thefoot 40 is pivotally mounted from theleg 14 about anaxis 44 which extends through theapex region 43 of thefoot 40. Thearcuate surface 42 is substantially equidistant along its length from thepivot axis 44. The pivot axes of both feet are coaxially aligned when the legs are in their extended position.

A latch means, generally indicated by the numeral 50, is interposed between each of the legs and its respective foot. As seen in FIG. 5, the latch means 50 includes a series ofnotches 51 formed in thearcuate surface 42. Alatch member 52 is carried by theleg 14 and is engageable with thenotches 51. As is best seen in FIG. 6, thelatch member 52 comprises abody 53 which is carried in aslot 54 formed through theleg 14. Thebody 53 has aninner end 55 which is engageable with thenotches 51. The outer end of thebody 53 comprises an integrally formedhead 56. Thehead 56 is so designed 'as to be readily grasped by an operator to translate thebody 53 in theslot 54. Thebody 53 further includes anelongated slot 57. Apin 58 extends through theleg 14 and through theslot 57 to limit the inward and outward movement of thelatch member 52 in theslot 54.

Referring to FIG. 7, the pivotal connection between the legs and the platform is more clearly shown. The platform 11 has depending integrally formedprojections 60. Each of theprojections 60 includes aslot 61 which terminates an enlargedcircular aperture 62. Thecircular apertures 62 are adapted to receive andjournal end portions 63 extending from opposite sides of each of the legs. Theend portions 63 have flattenedsurface portions 64, 65 which permit their insertion through theslot 61 into theaperture 62 when each of the legs is in the retracted position of FIG. 1. Upon rotation of the legs from their retracted position, theflat portions 63, 64 no longer align with theslots 61 and the legs are thereby held in position. Removal of the legs can only be accomplished with the legs in their retracted position.

Each of thelegs 14, 15 has planarbottom portions 70 which are adapted to support the platform 11 substantially horizontally whenthe legs are in their extended position. When the legs are in their retracted position, theplanar bottom portions 70 are closely spaced adja cent each other so as to prevent the removal of theend portions 63 of the legs from the tray 10. Each of thefeet 40, 41 also has planarbottom portions 71 which are adapted to extend beyond theplanar bottom portion 70 of the legs to support the platform 11 at selected angles of inclination tilted from the horizontal.

DESCRIPTION OF A SECOND EMBODIMENT Referring to FIG. 8, a tray is shown which represents the preferred embodiment of the invention at the time of filing the referenced abandoned continuationin-part application. Thetray 110 includes a platform 111 having a planartop portion 112. The platform 111 comprises a molded plastic material and includes an integrally formedperipheral rim 113. A pair oflegs 114, 115 are mounted beneath the platform 111 for pivotal movement about spacedparallel axes 116, 117. Thelegs 114, 115 are hollow and telescopically carryextensible feet 140, 141.

The overall appearance of thetrays 110 and 10 including the platforms 111 and 11, thelegs 114, 115 and 14, 15 and thefeet 140, 141 and 40, 41 are substantially similar and function in substantially identical manners. The major points of difference between thetray structures 110, 10 lie in the pivotal mountings of thelegs 114, 115 from the platform 11, an improved mechanism for locking thelegs 114, 115 in both their extended and retracted positions, and an improved mechanism for locking thefeet 140, 141 in both their retracted and extended positions.

A novel connection means, generally indicated by the numeral 120, is provided for connecting both sides of thelegs 114, 115 to the platform 111. Referring to FIGS. 17-19 wherein the connection of one side of theleg 114 to the platform 111 is illustrated in detail, the connection means includes acylindrical projection 121 formed integrally with theleg 114. A mountingblock 112 is formed integrally with the platform 111 and has adownwardly opening slot 123. Theslot 123 is of such size as will movably journal theprojection 121 without substantial play.

Theprojection 120 is held in the slot by means of a springbiased collar 124. Thecollar 124 is slidably positioned on theprojection 121. Acompression coil spring 125 is positioned on theprojection 121 in engagement with thecollar 124 so as to bias thecollar 124 toward the mountingblock 122. A pair ofpins 126 carried by the mountingblock 122 are received in a pair ofapertures 127 formed through thecollar 124.

During assembly, thecollars 124 on opposite sides of theleg 114 are moved inwardly along theprojections 121, as shown in FIG. 16, to compress thesprings 125. Theprojections 121 are then inserted into theslots 123. Theapertures 127 are then aligned with thepins 126 and the collars released so that the springs 12S move thecollars 124 toward the mounting blocks 122. Thepins 126 are thereby caused to extend through theapertures 127 to prevent theprojections 121 from sliding out of theslots 123.

A compact leg locking assembly, generally indicated by the numeral 130, is secured to the underside of the platform 11, as shown in FIG. 9. The assembly 130 includes atrack structure 131 forming a pair oftracks 132 which journal one end of each of a pair of T- shapedleg support rods 133. A pair of latching devices, indicated generally by thenumerals 150, are provided intermediate the ends of theslots 132 for locking thelegs 114, 115 in their extended positions. A pair of latching devices indicated, generally by thenumerals 160, are provided near the ends of thetrack structure 131 for locking thelegs 114, 115 in their retracted positions.

Referring to FIGS. 13 and 14, thesupport rods 133 each comprise rod-like stems having a T-shapedformation 134 at one end, and having an apertured flattenedregion 135 at the other end. The T-shapedformation 134 is slidably received in anenlarged recess 136 formed in the track structure 13-1 inwardly of theslot 132. The apertured flattenedregion 135 is pivotally connected by means of a pin 137 to ayoke 138. The yokehas a threaded portion 139 which is threaded into the associated leg, 114, 115.

Theslots 132 are enlarged adjacent theirinner ends 142 and their outer ends 143.,The enlargedinner end openings 142 provide access to therecesses 136 for inserting the T-shapedend formations 134 into therecesses 136 during assembly. The enlargedouter end openings 142 receive theyokes 138 when the legsare retracted as shown in FIG. 11. Therecesses 136 do not extend the entire length of theslots 132 but terminate at 144 adjacent the latching means 150.

Referring to FIG. 15, the latching means 150 each include abolt 151 slidably positioned in anaperture 152 formed in thetrack structure 131. A leaf spring 153 biases thebolt 151 inwardly. One end of the leaf spring 153 is supported in aslot 154 formed in thetrack structure 131. The other end of the leaf spring 153 is received within aslot 154 formedin the bolt.

The inner end 155 of thebolt 151 is tapered so that the T-shapedend 134 of therod 133 will force thebolt 151 outwardly as it passes by thebolt 151 in moving into engagement with theend wall 144. As the T- shapedend 134 comes into engagement with theend wall 144, thebolt 151 is released and travels inwardly under the influence of the spring 153 so as to hold the T-shapedend 134 against theend wall 144. This action of thelatch mechanism 150 serves to lock the associated legs in its extended position. To retract the legs, the outer end of thebolt 151 is grasped by the operator and pulled outwardly so as to let the T-shapedend 134 pass by inner end 155 of thebolt 151.

Thelatch mechanisms 160 which lock the legs in their retracted positions are best seen in FIGS. 10, 11 and 15. Each of thelatch mechanisms 160 includes a latchingrod 161 which is supported for sliding axial movement by thetrack structure 131. The end regions of thetrack structure 131 are provided with depending mounting blocks 162. Each of the mountingblocks 162 has a centrally locatedrecess 163 which carries acompression coil spring 164. Cover plates 165 overlie therecesses 163 and are adhered to the mounting blocks 162.Aligned apertures 166, 167 formed through opposite side walls of the mountingblocks 162 slidably support the latchingrods 161 and position them so as to extend through therecesses 163.

Thesprings 164 serve to bias the latchingrods 161 toward each other. A collar 168 is crimped rigidly in place on portions of the latching rods which extend through therecesses 163. Thesprings 164 are positioned on the latching rods in engagement with the collars 168 so as to bias therods 161 toward each other.

The inner ends 169 of the latchingrods 161 are rounded so as to be readily inserted intoapertures 170 formed in thelegs 114, 115. The outer ends 171 of the latchingrods 161 are curved so as to provide a fingerring type handle that can be readily grasped by an operator.

In order to lock thelegs 114, 115 in their retracted position the latchingrods 161 are pulled outwardly.

Thelegs 114, are then moved to their retracted position, and the latchingrods 161 are then released to as to project into the apertures under the influence of thesprings 164.

The aforedescribed leg mounting and latching structures, when combined in the described arrangment of the second embodiment provide a tray structure which is very easy to operate. By way of example, assume the legs 1 14, 1 15 are in their retracted position and the tray is loaded with dishes of food for serving to a patient lying in bed. As the tray is moved into position over the patient, all that needs to be done to lower the legs and lock them firmly in position is to pull the finger rings 171 outwardly. When the finger rings 171 are pulled outwardly, thelegs 114, 115 are released to permit their pivoting downwardly under the'influence of gravity. As the legs approach their extended positions, they have gained sufficient momentum to pull the T-shaped ends 134 of thesupport rods 133 past thebolts 151 such that the legs are firmly locked in their extended position.

Retracting the legs is a simple matter of releasing thebolts 151 and holding the finger rings 171 outwardly as the legs return to their retracted position. This simple procedure is most easily accomplished with the tray inverted so that the leg movement is again facilitated by the force of gravity.

An improved ratchet latching mechanism, indicated generally bythenumeral 180, is provided for adjustably positioning thefeet 140, 141 relative to thelegs 114, 115. Referring to FIGS. 12 and 16 where the ratchet mechanism which interconnects .thefoot 140 and theleg 114 is shown in detail, .thefoot 140 is pivotally mounted on theleg 114 at 181. Thefoot 140 includes a notchedarcuate surface 182.

Apawl 183 is slidably positioned in anaperture 184 formed in theleg 114 and is biased into engagement with thesurface 182 by aleaf spring 185. One end ofleaf spring 185 is carried in aslot 186 formed in theleg 114. The other end of theleaf spring 185 engages a notch 187 in thepawl 183.

Theinner end 188 of thepawl 183 is tapered to cooperate with the notchedsurface 182 to form a ratchet latching mechanism that will hold thefoot 140 in any of several extended positions. In order to retract the feet from their extended positions, the operator simply grips the outer ends of thepawls 183 and pulls them outwardly to permit the notchedsurface 182 to pass freely by theinner end 188 of thepawl 183.

Thepawls 183 serve the additional function of releasably holding thefeet 140, 141 in their retracted position. The biasing action of thesprings 185 is sufficiently strong such that when thefeet 140, 141 are retracted,

they will not extend under the influence of gravity but must be pulled downwardly by an operator.

Referring to FIG. 12, in order to provide thelegs 114, 115 with a symmetrical molded configuration, apawl mounting aperture 194 andspring mounting slot 196 are formed above the region of the pivotal mounting 181. No spring or pawl is positioned in these formations, however, and aplug 198 is secured in theaperture 194.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIGS. 20-21, atray 210 is shown which represents the preferred embodiment of the invention at the time of filing the present continuation-in-part application. Thetray 210 includes a moldedplastic platform 211 having a planartop portion 212 and an inte grally formedperipheral rim 213. A pair of long supportinglegs 214, 215 are pivotally mounted beneath theplatform 211. Thelegs 214, 215 are hollow and telescopically carryextensible feet 240, 241. Two pairs of short supportinglegs 232, 233, 234 and 235 are also pivotally mounted beneath theplatform 211 and serve to support the tray when thelong legs 214, 215 are retracted. As will be explained in greater detial, the short legs 232-235 also serve as latching devices for locking thelong legs 214, 215 in their extended position.

The major points of difference between thetray 210 and thetray 110 lies in the pivotal mountings of thelegs 214, 215 from theplatform 211, improved mechanisms for locking thelegs 214, 215 in their retracted position, an improved mounting of theextensible feet 240, 241 within thelong legs 214, 215, and the provision of short legs 232-235 which serve the dual functions of releasably latching thelong legs 214, 215 in their extended position and supporting thetray 210 when thelong legs 214, 215 are retracted.

- Thelong legs 214, 215 are pivotally connected to the underside of theplatform 211 by means of two pairs-of plastic hinges 220,221 and 222, 223. Referring to FIG. 24, one of thehinges 221 is illustrated in cross section. Opposite ends 221a, 221b of thehinge 221 are received in slots formed in theleg 214 and the underside of theplatform 212. A suitable adhesive holds theends 221a, 221b in place. A central region 2210 of reduced cross section is formed in thehinge 221, to confine the bending of the hinge to a relatively small region intermediate theends 221a, 221b.

When thelong legs 214, 215 are in their retracted position, they are latched securely beneath theplatform 211 by primary leg locks 222, 223. The leg locks 222, 223 include latchingmembers 224, 225 slidably carried withinhousings 226, 227. The latchingmembers 224, 225 are adapted to overlie central portions of thelong legs 214, 215, as shown in FIG. 21, to latch the long legs in their retracted position.Control members 228, 229 are provided to release the latchingmembers 224, 225. Since the primary leg locks 222, 223 are identical in construction, only theleg lock 222 will be described in detail.

Referring to FIGS. 27, 28, the latchingmember 224 is of J -shaped configuration including a stern 224a having anenlarged end portion 224b, and a transversely projectingportion 224C terminating in a latchingprojection 224d. The stem 224a and itsend portion 224b are slidably carried within a channel 226a formed in thehousing 226. The projecting portion 224a extends through a slot 226b formed in an end region of thehousing 226. The latchingprojection 224d is adapted to overlie a central region of thelong leg 214 to latch it in its retracted position, as shown in FIG. 21.

The latching member is biased to the latched position of FIGS. 21, 27, 28 by acompression coil spring 230. Thespring 230 is positioned within the channel 226a between the enlarged end portion 22412 and a dependingprojection 226c formed inwardly of thehousing 226. Thespring 230 operates to bias the latchingmember 224 in the direction ofarrow 231 to bring theprojection 224c into engagement with the end of the slot 226b.

Thecontrol member 228 includes a base portion 228a which is slidably mounted within the channel 226a. An upstanding knob-like projection 228b formed integrally with the base 228a extends through aslot 226d formed in thehousing 226. One end of the base 228a abuts the end region 2241) of the latchingmember 224. Movement of theknob 228 in the direction ofarrow 232 will cause concurrent movement of the latchingmember 224 to release thelong leg 214 from its retracted position. Thespring 230 effects return of the latchingmember 224 and thecontrol member 228 to the position of FIGS. 27, 28 once the knob 228b is released.

The short legs 232-235 serve dual functions. In one capacity they support thetray 210 when thelong legs 214, 215 are retracted. In a second capacity, the short legs 232-235 serve to latch thelong legs 214, 215 in their extended position. Sinceall four of the short legs are substantially identical (two are left and two are righ) only theleg 223 will be described in detail.

Referring to FIGS. 23-26 and 29, theshort leg 233 includes abase portion 233a and an integrally formedupstanding portion 233b. Theleg 233 is pivotally mounted by apin 236 for pivotal movement about the axis of thepin 236 in directions toward and away from thelongleg 214 as indicated by thearrows 237.

Acover plate 238 is provided adjacent thebase portion 233a of theshort leg 233. Thecover plate 238 is adhered by suitable adhesive to a raisedregion 212a of theplatform 212. A slot 238a is formed in thecover plate 238, as best seen in FIG. 29. A dependingprojection 233e formed on theshort leg 233 extends through the slot 238a into aregion 239 between thecover plate 238 and theplatform 212.

A wire spring 239a'biases theshort leg 233 toward thelong leg 214. One end region of thespring 239a is embedded in the raisedplatform region 212a, as shown in FIG. 29. The other end region of thespring 239a rests against the dependingprojection 233e. Thespring 239a extends through theregion 239 along a curved path, as shown in FIG. 25 to preload thespring 239a.

A hook-shapedformation 233d is provided on theshort leg 233. Theformation 233d wraps around one side of thecover plate 238, as shown in FIG. 29, and maintains theleg 233 in contact with thecover plate 238.

Acam surface 233e is formed on the surface of theshort leg 233 which faces thelong leg 214. Thecam surface 233e is configured such that as thelong leg 214 is moved from its retracted to its extended position, aside 214a of theleg 214 contacts the cam surface 2332 and causes theshort leg 233 to pivot about thepin 236 in a direction away from thelong leg 214.

Aslot 233f is also formed in the surface of theshort leg 233 which faces thelong leg 214. Theslot 233f is adapted to receive theside 214a of thelong leg 214 when thelong leg 214 reaches its extended position. When theside 214a is received in theslot 233f, theshort leg 233 is then free of pivot inwardly toward thelong leg 214 under the influence of thespring 239a to latch thelong leg 214 in its extended positions. Since two of the short legs 232-235 operate on each of thelong legs 214, 215 to latch opposite sides of the long legs, a very secure latching action is provided to maintain the long legs in their extended position.

Thelong legs 214, 215 are released from their extended latched positions by the same control knobs 228, 229 as release the long legs from their retracted latched positions. The type of latch release mechanism which effects the release of the long legs from their extended position is illustrated in FIG. 27.

Referring to FIG. 27,,a pair ofslides 272, 273 extend from within thehousing 226 and into engagement with theshort legs 232, 233, respectively. The inner ends of theslides 272, 273 have inclinedsurfaces 272a, 273a formed thereon which engage the base 228a of thecontrol member 228. Theinclined surfaces 272a, 273a are arranged such thatmovement of thecontrol member 228 in the direction ofarrow 231 will cause theslides 272, 273 to move away from each other therebypivoting theshort legs 232, 233 away from thelong leg 214. Thespring 239a and its counterpart in theleg 232 serve to bias theslides 272, 273 inwardly and to bias thecontrol member 228 to the position of FIG. 27.

In operation, moving thelong legs 214, 215 from their retracted to their extended position is accomplished simply by positioning the tray as shown in FIG. 20 and moving thecontrol members 228, 229 toward each other to release the latchingmembers 224, 225. Thelong legs 214, 215 are then pivoted under the influence of gravity to their extended position. During movement to the extended position, thelong legs 214, 215 cam the short legs outwardly. As thelong legs 214, 215 reach their extended position, the short legs 232-235 snap inwardly to latch the longlegs in place.

Moving the long legs from their extended to their retracted position is accomplished simply by moving thecontrol members 228, 229 away from each other to cam the short legs 232-235 outwardly,.whereupon thelong legs 214, 215 are folded inwardly. As thelong legs 214, 215 approach their retracted positions, they contact the rounded end of the latchingmembers 224, 225 causing thelatching'members 224, 225 to travel toward each other. As thelong legs 214, 215 reach their retracted position, the latchingmembers 224, 225 snap to their latched positions.

In the preferred embodiment, theextensible feet 240, 241 comprise arcuate segments movable along an arcuate path. Referring to FIG. 22, theextensible foot 240 is movable along a path having a center of curvature at thepoint 244. As will be seen by comparing the structure of the preferred embodiment with the structures of the aforedescribed embodiments, the resulting tilting function of thefeet 240, 241 as compared to thefeet 140, 141 and 40, 41 is identical. In all instances, thefeet 240, 241 and 140, 141 as well as 40, 41 provide a planar bottom surface which, by virtue of the arcuate movement of the foot, extends into parallel surface contact with a supporting surface regardless of the angle to which the tray is tilted.

Thefeet 240, 241 are provided with ratchet type latches 283 quite similar in configuration to those described in conjunction with thefeet 140, 141. Referring to FIG. 22,thelatches 283 each include alever 284 pivotally mounted internally of its supporting leg by apin 285. Aleaf spring 286 carried inwardly of the leg biases theinner end 284a of thelever 284 into engagement with a knotched surface formed on the associatedfoot 240, 241.

In operation, thefeet 240. Ml are extended by grasping the lower ends thereof and pulling them outwardly of thelegs 214, 215 to the desired degree of extension. In each of several extended positions defined byknotches 287 along thefeet 240, 241, the levers Thefeet 240, 241 are retracted simply by pivoting thelevers 284 to release their engagement with theknotches 287, whereupon the feet can be retracted by pushing them into thelegs 214, 215.

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

What is claimed is:

l. A tray structure comprising:

a. a platform defining a planar top surface;

b. a pair of legs pivotally carried beneath said platform near opposite end regions thereof and being movable between a retracted position where said legs are folded beneath 'said platform to an extended position where said legs depend from said platform to support said platform at an elevated height above a' horizontal supporting surface;

c. leg locking meansinterposed between said platform and said legs for selectively locking said legs in said retracted and extended positions;

d. a pair of extensible feet each being movably carried by a separate one of said legs and each being movable along an arcuate path between a retracted position where bottom portions of said feet cooperate with said legs to support said platform horizontally above a horizontal supporting surface when said legs are extended, to extended positions where said bottom portions depend from said legs; and

e. feet locking means interposed between said feet and said legs for locking said feet selectively at one of a plurality of predetermined extended positions for supporting said platform in inclined attitudes relative to a horizontal supporting surface.

2. The tray structure of claim 1 wherein said feet are telescopically carried in downwardly opening recesses formed in said legs.

3. The tray structure ofclaim 2 wherein:

a. said feet have the general shape of circular sectors and are pivotally connected to said legs in the region of the apex of said circular sectors; and,

b. the axes of pivotal connection between said feet and said legs are substantially coaxially aligned when said legs are in said extended position.

4. The tray structure ofclaim 2 wherein:

a. said feet have the general shape of arcuate segments; and g b. said recesses each have at least one curved wall which slidably engages its respective foot to guide said foot for movement along said arcuate path. 5. The tray structure of claim 1 wherein said feet locking means includes a plurality of notches formed in each of said feet and a latch member carried by each of said legs and engageable with said notches to selectively lock said feet in said predetermined extended positions.

6. The tray structure of claim I wherein said leg locking means includes:

a. first latch means movably carried by said platform for releasably engaging said legs when said legs are in said retracted position; and

b. second latch means movably carried by said platform for releasably engaging said legs when said legs are in said extended position.

7. The tray structure of claim 6 wherein said leg locking means additionally includes a pair of actuators movably carried by said platform, one of said actuators being associated with each of said legs and being operable to release said first and second latch means associated with its respective leg.

8. The tray structure of claim 6 wherein said secon latch means includes:

a. a separate pair of support members associated with each of said legs and being pivotally carried by said platform;

b. biasing means biasing said support members into engagement with said legs when said legs are in their extended position to releasable retain said legs in their extended position.

9. The tray structure ofclaim 8 wherein said support members have bottom end regions which depend from said platform and are operable to support said platform above a horizontal surface when said legs are in their retracted position.

10. The tray structure of claim 1 wherein said leg locking means includes manually actuated means operable to release said legs from their retracted position thereby permitting the pivotal movement of said legs under the influence of gravity to their extended position, said leg locking means being automatically operable to lock said legs in their extended position.

11. The tray structure of claim 1 wherein said leg locking means includes a separate manually operated actuator associated with each of said legs, each of said actuators being operable to release its associated leg from the locking action of said leg locking means when said associated leg is in either of said retracted and extended positions.

12. The tray structure of claim 1 additionally including four supports which below said platform when said legs are retracted to support said platform above a horizontal supporting surface.

13. The tray structure ofclaim 12 wherein said supports are carried by said legs and are operable when said legs are in their extended position to serve as stops engaging said platform to limit the movement of said legs.

14. A tray structure comprising:

a. a platform defining a planar top surface;

b. a pair of legs pivotally carried near opposite sides of the platform, each of said legs being movable along a path between a retracted position folded beneath the platform to an extend position depending from the platform;

c. a pair of feet, each being carried by a separate one of said legs and each being extensible beyond the bottom of its associated leg;

d. means for locking said legs in said extended position including:

i. at least one locking member associated with each leg and being pivotally carried by said platform at a position along said path of movement of its associated leg;

ii. each of said locking members having a slot formed therein for receiving and retaining a portion of its associated leg when said leg is in its extended position; and

iii. biasing means biasing said locking members into retaining engagement with said legs when said legs are in their extended position.

15. The tray structure ofclaim 14 wherein each of said locking members has cam surfaces portions formed thereon which are engaged by said associated leg as said associated leg approaches its extended position, said engagement between said cam surface portions and said associated leg being operable to pivot the respective locking member transversely of said path of leg movement to increase the biasing force exerted on the respective locking member by said biasing means thereby assuring that said biasing means will be operative to effect positive retaining engagement between said legs and said locking members when said legs reach their extended position.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION.

Patent No. 3 I 859 930 Dated January 14 I 1975 Peter G; Sherwin Inventor(s) It is certified that error eppears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1,line 33, delete "the" and substitute The Column 4,line 55, insert after "one" the word end Column 9, line 11, delete "detial" and substitute detail Column 10,line 20, delete "righ" and substitute right Signed and sealed this 13th day of. May 1975.

(SEAL) Attest:

C. MARSHALL DANN RUTH C. MASON Commissioner of Patents Attesting Officer and Trademarks FORM USCOMM-DC wave-ps9 U 5. GOVERNMENT PFINYING OFFICE I," O-JGG-Jll

Claims (15)

1. A tray structure comprising: a. a platform defining a planar top surface; b. a pair of legs pivotally carried beneath said platform near opposite end regions thereof and being movable between a retracted position where said legs are folded beneath said platform to an extended position where said legs depend from said platform to support said platform at an elevated height above a horizontal supporting surface; c. leg locking means interposed between said platform and said legs for selectively locking said legs in said retracted and extended positions; d. a pair of extensible feet each being movably carried by a separate one of said legs and each being movable along an arcuate path between a retracted position where bottom portions of said feet cooperate with said legs to support said platform horizontally above a horizontal supporting surface when said legs are extended, to extended positions where said bottom portions depend from said legs; and e. feet locking means interposed between said feet and said legs for locking said feet selectively at one of a plurality of predetermined extended positions for supporting said platform in inclined attitudes relative to a horizontal supporting surface.

2. The tray structure of claim 1 wherein said feet are telescopically carried in downwardly opening recesses formed in said legs.

3. The tray structure of claim 2 wherein: a. said feet have the general shape of circular sectors and are pivotally connected to said legs in the region of the apex of said circular sectors; and, b. the axes of pivotal connection between said feet and said legs are substantially coaxially aligned when said legs are in said extended position.

4. The tray structure of claim 2 wherein: a. said feet have the general shape of arcuate segments; and b. said recesses each have at least one curved wall which slidably engages its respective foot to guide said foot for movement along said arcuate path.

5. The tray structure of claim 1 wherein said feet locking means includes a plurality of notches formed in each of said feet and a latch member carried by each of said legs and engageable with said notches to selectively lock said feet in said predetermined extended positions.

6. The tray structure of claim 1 wherein said leg locking means includes: a. first latch means movably carried by said platform for releasably engaging said legs when said legs are in said retracted position; and b. second latch means movably carried by said platform for releasably engaging said legs when said legs are in said extended position.

7. The tray structure of claim 6 wherein said leg locking means additionally includes a pair of actuators movably carried by said platform, one of said actuators being associated with each of said legs and being operable to release said first and second latch means associated with its respective leg.

8. The tray structure of claim 6 wherein said second latch means includes: a. a separate pair of support members associated with each of said legs and being pivotally carried by said platform; b. biasing means biasing said support members into engagement with said legs when said legs are in their extended position to releasable retain said legs in their extended position.

9. The tray structure of claim 8 wherein said support members have bottom end regions which depend from said platform and are operable to support said platform above a horizontal surface when said legs are in their retracted position.

10. The tray structure of claim 1 wherein said leg locking means includes manually actuated means operable to release said legs from their retracted position thereby permitting the pivotal movement of said legs under the influence of gravity to their extended position, said leg locking means being automatically operable to lock said legs in their extended position.

11. The tray structure of claim 1 wherein said leg locking means includes a separate manually operated actuator associated with each of said legs, each of said actuators being operable to release its associated leg from the locking action of said leg locking means when said associated leg is in either of said retracted and extended positions.

12. The tray structure of claim 1 additionally including four supports which below said platform when said legs are retracted to support said platform above a horizontal supporting surface.

13. The tray structure of claim 12 wherein said supports are carried by said legs and are operable when said legs are in their extended position to serve as stops engaging said platform to limit the movement of said legs.

14. A tray structure comprising: a. a platform defining a planar top surface; b. a pair of legs pivotally carried near opposite sides of the platform, each of said legs being movable along a path between a retracted position folded beneath the platform to an extend position depending from the platform; c. a pair of feet, each being carried by a separate one of said legs and each being extensible beyond the bottom of its associated leg; d. means for locking said legs in said extended position including: i. at least one locking member associated with each leg and being pivotally carried by said platform at a position along said path of movement of its associated leg; ii. each of said locking members having a slot formed therein for receiving and retaining a portion of its associated leg when said leg is in its extended position; and iii. biasing means biasing said locking members into retaining engagement with said legs when said legs are in their extended position.

15. The tray structure of claim 14 wherein each of said locking members has cam surfaces portions formed thereon which are engaged by said associated leg as said associated leg approaches its extended position, said engagement between said cam surface portions and said associated leg being operable to pivot the respective locking member transversely of said path of leg movement to increase the biasing force exerted on the respective locking member by said biasing means thereby assuring that said biasing means will be operative to effect positive retaining engagement between said legs and said locking members when said legs reach their extended position.

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