US3814492A - Cantilever shelf assembly with pantography support arrangement for refrigerators - Google Patents

Abstract

A refrigerator shelf assembly for moving a plurality of cantilevered vertically stacked adjustable shelves to a staggered extended position by a pair of composite stringer linkage mechanisms each pivotally supported in spaced relation to the refrigerator and movable in parallel vertical planes in a pantograph manner while maintaining the shelves in horizontally disposed relation, together with actuator means for automatically moving the shelves.

Description

United States Patent [191 Jacobs [5 1 CAN'llLEVER SHELF ASSEMBLY WITH PANTOGRAPHY SUPPORT ARRANGEMENT FOR REFRIGERATORS [75] Inventor: James W. Jacobs, Dayton, Ohio [73] Assignee: General Motors Corporation, Detroit, Mich.

[111 3,814,492 1 June 4, 1974 2,654,345 10/1953 Edwards 312/271 2,795,691 6/1957 Solley et a1. 312/223 X 2,956,766 10/1960 Galassi 248/243 3,139,258 6/1964 Handler et al....... 248/243 3,177,988 4/1965 Costantini et al.... 248/243 X 3,231,732 1/1966 Ferguson 312/223 X 3,578,833 5/1971 Frederick 312/273 3,712,521 1/1973 Tanner 211/150 X Primary Examiner-Paul R. Gilliam Attorney, Agent, or Firm-Edward P. Barthel [57] ABSTRACT A refrigerator shelf assembly for moving a plurality of cantileveredvertically stacked adjustable shelves to a staggered extended position by a pair of composite stringer linkage mechanisms each pivotally supported in spaced relation to the refrigerator and movable in parallel vertical planes in a pantograph manner while maintaining the shelves in horizontally disposed relation, together with actuator means for automatically moving the shelves.

5 Claims, 9 Drawing Figures CANTILEVER SHELF ASSEMBLY WITH PANTOGRAPHY SUPPORT ARRANGEMENT FOR REFRIGERATORS This invention relates to refrigerator cabinet shelves and more particularly to a refrigerator shelf mechanism for moving a plurality of cantilevered adjustable shelves to a staggered extended position while maintaining the shelves in horizontally disposed relation.

It is therefore an object of this invention to provide a pair of pantograph linkage mechanisms in combination with a plurality of cantilevered supported adjustable shelves for a cabinet structure whereby the shelves are movable in unison to an outer staggered position while being maintained in a horizontal attitude.

It is another object of the invention to provide a shelf assembly for a refrigerator cabinet including a plurality of cantilevered vertically stacked adjustable shelves, each supported by rearwardly extending upper and lower hook-like projections, for movement of the shelves in unison to a staggered extended position on a pair of composite apertured stringers wherein each composite stringer comprises a pair of coextensive channels dimensioned to be nested in opposed box-like sections such that each channel is pivotally attached to the cabinet at its upper end while the free ends of the channels are pivotally linked together providing a pair of linkage mechanisms movable in spaced-parallel vertical planes in a pantograph manner. The upper and lower projections of each shelf have cammed forwardly and rearwardly facing arcuate edges respectively operatively engaging its associated composite stringer maintaining the horizontal position of the shelves while the assembly is moved either manually or by power assist means to an extended or retracted position.

Other objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred embodiment of the present invention is clearly shown.

In the Drawings:

FIG. 1 is a perspective view of a refrigerator cabinet with the door shown in open position and the shelf assembly extended;

FIG. 2 is a vertical side view partly in section and partly in elevation of the cabinet of FIG. 1 with the shelf assembly shown in full lines in retracted position;

FIG. 3 is an enlarged fragmentary detail view partly in section of the rear mounting tabs and upper pivotal support, partly in section with the shelf assembly shown in retracted position;

FIG. 4 is an enlarged fragmentary detail view of the rear mounting tabs and lower pivotal link partly in section with shelf assembly shown in extended position;

FIG. 5 is a horizontal section taken on the line S-.5 of FIG. 3;

FIG. 6 is an enlarged fragmentary detail view partly in section of the shelf assembly linear motor actuator;

FIG. 7 is an enlarged section taken on the line 7-7 of FIG. 6; v

FIG. 8 is a schematic wiring diagram for power extending the shelf assembly;

FIG. 9 is an optional schematic wiring diagram for power extending and returning the shelf assembly.

Referring to the drawings, for illustrating my invention. I show in FIGS. 1 and 2 thereof a generally rectangular cabinet 10 of a household refrigerator or freezer. The refrigerator cabinet 10 includes an outer sheet metal shell 11 and an inner box-like plastic liner I2 spaced from the shell and having any suitable or desirable insulating material l3 disposed therebetween. as seen in FIG. 3. Liner 12 forms rectangular walls of a polygonal-shaped food storage chamber 14 between top wall 15 and lower storage bins 16 within cabinet 10 which is practical for maximum food storage space, and wherein my invention is particularly applicable. Food storage chamber 14 is provided with an open front access opening 17 which is normally closed by an insulated door structure generally represented by the reference character 18 hingedly secured to one vertical edge of the cabinet 10 by suitable hinges 20 for horizontal swinging movement relative thereto.

As best seen in FIGS. 3, 4 and 5, the liner includes a rear wall 21 having horizontally spaced pivotal means for supporting two composite stringers 22, 23. Each composite stringer or linkage mechanism has its upper end received by respective U-shaped brackets 24 and 25 which are suitably secured by their base flanges to the rear wall 21 of the liner adjacent the juncture with top wall 15 such as by screws 26. As each of the composite stringers are identical, common reference numerals will be used to designate corresponding portions thereof.

Each of the composite stringers 22, 23 comprise apair of elongated coextensive front and rear channel members 31 and 32 respectively dimensioned such that smaller sectioned front channel member 31 is nestably received within larger sectioned rear channel member 32. The front channel member 31 has a pair of upstanding ears 35 and 36 having aligned apertures therethrough to receive a first transverse pin 38 therethrough which has its outer extremities pivotally supported in aligned apertures in the side flanges 39 and 40 of the U-shaped brackets to allow for relative pivotal movement between the inner front channel member 31 and the rear outer channel member 32. In a similar manner the rear channel member 32 has a pair of upwardly extending ear portions 42 and 43 having aligned apertures therein for reception of a second transverse pin 44, the extremities of which are pivotally supported in the side flanges 39 and 40 of its associated U-shaped bracket 24, to allow the rear channel member 32 to pivot relative to the front channel member 31. It will be noted in FIG. 3 that the pivotal axis of each of the first and second pins 38 and 44 are aligned in spaced parallel relation in a common horizontal plane. The front inner channel member 31 has a plurality of equally spaced apertures 50 in its transverse wall such that the apertures 50 form cross webs 52 therebetween.

A plurality of article supporting cantilevered shelves or trays are located in the cabinet 14 which in the disclosed embodiment comprise three identical trays indicated generally at 61, 62 and 63. As best shown in FIGS. 1 and 3, each shelf includes a pair of opposite side brackets or beams 66 and 67 such that each pair of side members define a shelf unit and support a top plate 68 which is suitably secured to the upper edge of the side beams 66 and 67 such as by welding. The rear portion of each side bracket includes upper and lower hook-like projections 71 and 72 and a bottom tab 73 such that the upper projection 71 is received in one aperture 50aof the front channel member 31 with the downwardly extending hook engaging behind the associated web 52 of the channel below the aperture 50a while the bottom tab 73 is received in an aperture designated 50c.'The forward edge of upper projection 71 is outwardly curved to provide a first arcuate camming edge 74 designed to contact and ride against its associated web 52 while the rear edge 75 is spaced from the transverse wall 77 of rear channel 32 at all times. The lower projection 72 is received in the aperture 501) such that its downwardly extending hookhas its rearward edge portion outwardly curved to provide a second arcuate camming edge 76 dimensioned to engage and ride against the transverse wall 77 of the rear channel 32. The arcute cam 76 allows the projection 72 to compensate for the reduction in spacing from a greater normal distance X (FIG. 3) to a lesser normal distance Y (FIG. 4) between the respective transverse wall 77 and the webs 52 of the rear and front channels as they are pivoted outwardly.

The lower extremities of each of the front and rear nested channels 31, 32 are similarly each provided with a pair of ears 81, 82 which extend downwardly with each pair having aligned apertures therein to receive first and second transverse pivot pins 83, 84 therethrough for pivotal engagement with pairs of link members 88. The pins 83 and 84 are located in a horizontal plane and are spaced a distance equal to the space between the upper pins 38 and '44'such that each of composite stringers 22, 23 functions as a pantograph member whereby when it is pivoted outwardly from the rear wall 25'the lower links 88 and upper brackets are so connectedand proportioned as to length in the form of a parallelogram that any motion of one point in a plane parallel to that of each composite stringer mechanism will cause another point to follow a similar path.

In this manner when the shelves 61, 62 and 63 are supported on the composite stringers22, 23 in the horizontal attitudes and in vertically stacked spaced apart relation they, are arranged to be moved in unison through the open front access opening 17 to the broken line position shown in FIG. 2.

1 Positioned in the lower portion of the refrigerator cabinet is a linear induction motor 90 which is preferably of the flat type, i.e., it is essentially a squirrel cage motor split along the armature axis and unrolled into a flat plane. One example of a flat linear induction motor is disclosed in US. Pat. No. 3,335,300 issued-Aug. 8, 1967 to Von Brimer, and reference should be had to this patent for details of its operation.

The movable element or armature 92 of the linear induction motor actuator 90 preferably is shaped with an l-cross section as seen in FIG. 7 of the drawings. Armature 92, formed of a conductive material, is slidably mounted between a magnetic keeper element 94 and the primary or stator 96 having windings 98 which may be selectively energized to correspondingly move the armature up or down bycircuit means to be described. The linear motor 90 is enclosed in a housing 100 having flanges 102 for suitably affixing the motor to the rear wall 21 of the cabinet by fasteners 104. Outer nylon bearing surfaces indicated at 106 and inner nylon bearing surfaces 108 are provided to guide the vertical travel of the armature.

The upper end of the armature 92 has suitable stop means thereon in the form of a stop connector 110 operably mounted on one end of a control wire 112 which has a loop 114 on the other end thereof operably attached to a connector pin 116 located on the side member 67 of the lowermost shelf so that vertical upward movement of the armature 92 produces a corresponding movement of the shelf assembly to move the shelves to their outer-extended position. Surrounding the wire 112 is a flexible sheath 120 which is conventionally anchored at each end to the wire support 122 which is screwed to the rear wall of the cabinet at 124. Push-pull control wire systems, also known as Bowden controllers," are disclosed, for example, in US. Pat. No. 3,546,962 issued Dec. 15, 1970 to Ruhala and assigned to the assignee of the instantapplication. and reference may be had to the Ruhala patent for details of a typical control wire structure. In FIG. 6 the actuator means is shown in its shelf assembly retracted position wherein the stop member is bottomed on the upper surface of the linear motor housing 100. While the disclosed form shows one actuator means 90 driving the left hand linkage mechanism 22 only, itis within the scope of the invention that a second actuator means could be employed to simultaneously drive the right hand linkage mechanism 23.- I

With reference to F IG. 1, a door switch is shown on the lower mullion of the cabinet which is actuated by disengagement with the door 18 of the refrigerator and is serviced through a circuit shown in FIG. 8 to close the switch 130 to fixed contact 131- energizing the circuit L, to line L through conductors 132 and 133 to ashelfposition control switch 136 located at a convenient height on the vertical mullion strip 138 of the cabinet which is shown as a single pole-single throw normally openswitch having its movable contact 140 in open position engaging fixed open contact 141. ln"

operation and with the door opened the user can-close the shelf position control switch 136 by moving the movable contact 140 into engagement with fixed contact 142 energizing the coils 98 .to the line L through a phase shifting capacitor 144 whereby the linear motor actuator 92 moves upwardly transmitting up-' ward motion to the wire 112 which in turn pivots the shelf assembly to. its outward phantom line position of FIG. 2. The shelf assembly is held in this position as long as switches 130 and 136 are closed. In this form of the invention the'shelf assembly is returned to its normally retracted position by means of gravity or by a small force imparted by the operator.

A modified circuit arrangement is shown in FIG. 9 with similar elements having the same reference numerals whereby a single pole-double throw switch is utilized with the actuator 90 such that with the door 18 opened to close switch 130 to contact 131, and with the movable contact 151 positioned to fixed contact 152, the actuator 90 moves the shelf assembly to its outer extended position. in this arrangement when the movable contact 151 is subsequently moved to engage fixed contact 153 a circuit is completed to the other side of the line L causing the armature to move downward and power return the shelves to their retracted position. Therefore it is apparentthat depending upon the position of movable contact 151, the shelves can be caused to automatically extend whenever door 18 is opened sufficiently to close switch 130 against contact 131 and movable contact .151 is positioned to fixed contactl52. On the other hand, if the movable contact 151 is positioned against fixed contact 153, the shelves will remain within the cabinet, even though switch 130 is closed against contact 13]. Obviously, whenever the door is moved sufficiently toward its closed position to move switch 130- away from contact 131 the actuator is deactivated and the shelf assembly may return by gravity or by a manual assist to its inner position.

While the embodiment of the present invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted.

I claim:

1. In a cabinet comprising wall structure defining a box-like storage compartment provided with a front access opening and a door for said opening, said wall structure including a rear wall and opposite side walls, a shelf assembly including a plurality of cantilevered horizontally disposed shelves supported in said compartment one above the other by means of a plurality of spaced apart pantograph-type composite stringer linkages, a bracket for pivotally supporting each said stringer linkage solely from said rear wall of said compartment for travel in a common vertical plane resulting in combined upward and outward movement of said shelf assembly from an inner retracted position to an outer extended position, each said composite stringer linkage being vertically oriented in said cabinet when said shelf assembly is in its retracted position, each said composite stringer linkage including a pair of outer and inner coextensive elongated structural elements, said outer structural element having a transverse wall provided with vertically spaced openings therein, each of the shelves having a plurality of spacedcantilever support arms, each said support arm rear portion including upper and lower hook-like projections arranged to be directed into respective ones of said spaced openings in its associated outer structural element whereby it is supported in cantilevered fashion therefrom, said upper projection having its forward edge outwardly curved to provide a first arcuate camming edge wedgingly contacting the inner face of said outer structural element transverse wall, said lower projection having its rearward edge outwardly curved to provide a second arcuate camming edge wedgingly contacting the inner face of said inner structural element transverse wall, each said structural element pivoted at its upper end to its associated bracket, link means pivotally connecting the lower ends of each pair of said structural elements, the pivots of said bracket and the link means of each pair of structural elements being positioned to lie in the four corners of a parallelogram linkage whereby said shelf assembly may be angularly moved from said retracted position to an outer extended position, said support arms first and second arcuate camming edges being shaped to maintain opposed sliding wedged contact with their associated channel faces whereby said shelves are moved into stepped relation in their extended position with no substantial tilting from the horizontal.

2. The combination of claim 1 including electric motor driven stringer linkage actuating means connected to at least one of said linkages for angularly moving said one linkage whereby said shelf assembly will be moved from its retracted position to an extended position.

3. ln a refrigerator cabinet comprising wall structure defining a box-like storage compartment provided with a front access opening and a door for said opening, said wall structure including a rear wall and opposite side walls, a shelf assembly including a plurality of horizontally disposed cantilevered shelves supported in said compartment in vertically stacked relation therein by means of first and second spaced apart pantographtype composite stringer linkages, a bracket for pivotally supporting each said stringer linkage solely from said rear wall of said compartment for travel in a common vertical plane resulting in combined upward and outward movement of said shelf assembly from an inner retracted position to an outer extended position, each said first and second composite stringer linkage being vertically oriented in said cabinet at a corner juncture defined by said rear wall and its adjacent side wall when said shelf assembly is in its retracted position, each said composite stringer linkage including a pair of outer and inner coextensive channels dimensioned to nest in opposed relation to form a box-shaped section, said outer channel having its transverse wall provided with vertically spaced openings therein, each of the shelves having a pair of spaced cantilever support arms, each said support arm rear portion including upper and lower hook-like projections arranged to be directed into respective ones of said spaced openings in its associated outer channel whereby it is supported in cantilevered fashion therefrom, said upper projection having its forward edge outwardly curved to provide a first arcuate camming edge wedingly contacting the inner face of said outer channel transverse wall, said lower projection having its rearward edge outwardly curved to provide a second arcuate camming edge wedgingly contacting the inner face of said inner channel transverse wall, each said channel pivoted at its upper end to its associated bracket means, link means pivotally connecting the lower ends of said nested channels, the pivots of said bracket and said link means of each being positioned to lie in the four corners of a parallelogram linkage whereby upon said shelf assembly being angularly moved from said retracted position to an outer extended position, said support arms first and second arcuate camming edges being shaped to maintain opposed sliding wedged contact with their associated faces whereby said shelves are moved into stepped relation with no substantial tilting from the horizontal.

4. In a cabinet comprising wall structure defining a box-like storage compartment provided with a front access opening and a door for said opening, said wall structure including a rear wall and opposite side walls, a shelf assembly including a cantilevered horizontally disposed shelf supported in said compartment by means of a plurality of spaced apart pantograph-type composite stringer linkages, a U-shaped bracket for pivotally supporting each said stringer linkage solely from said rear wall of said compartment for travel in a common vertical plane resulting in combined upward and outward movement of said shelf assembly from an inner retracted position to an outer extended position, each said composite stringer linkage being vertically oriented in said cabinet when said shelf assembly is in its retracted position, each said composite stringer linkage including a pair of outer and inner coextensive elongated structural elements, said outer structural element having a transverse wall provided with vertically spaced openings therein, said shelf having a plurality of spaced cantilever support arms, each said support arm rear portion including upper and lower hook-like projections arranged to be directed into respective ones of said spaced openings in its associated outer structural 7 element whereby it is supported in cantilever fashion therefrom, said upper projection having its forward edge outwardly curved to provide a first arcuate camming edge wedgingly contacting the inner face of said outer structural element transverse wall, said lower projection having its rearward edge outwardly curved to provide a second arcuate camming edge wedgingly contacting the inner face of said inner structural element transverse wall, each said structural element pivoted at its upper end to its associated bracket, link means pivotally connecting the lower ends of each pair of said structural elements, the pivots of the bracket means and the link means of each pair of structural elements being positioned to lie in the four corners of a parallelogram linkage whereby said shelf assembly being angularly movable from said retracted position to an outer extended position, said support arms first and motor to move said shelf assembly from its retracted position to an outer extended position.

5. The combination of claim 4 including shelf position control switch means for selectively energizing the windings of said linear electric motor whereby said motor may be reversed to move said shelf assembly either to an extended or retracted position upon the opening of said door.

Claims (5)

1. In a cabinet comprising wall structure defining a box-like storage compartment provided with a front access opening and a door for said opening, said wall structure including a rear wall and opposite side walls, a shelf assembly including a plurality of cantilevered horizontally disposed shelves supported in said compartment one above the other by means of a plurality of spaced apart pantograph-type composite stringer linkages, a bracket for pivotally supporting each said stringer Linkage solely from said rear wall of said compartment for travel in a common vertical plane resulting in combined upward and outward movement of said shelf assembly from an inner retracted position to an outer extended position, each said composite stringer linkage being vertically oriented in said cabinet when said shelf assembly is in its retracted position, each said composite stringer linkage including a pair of outer and inner coextensive elongated structural elements, said outer structural element having a transverse wall provided with vertically spaced openings therein, each of the shelves having a plurality of spaced cantilever support arms, each said support arm rear portion including upper and lower hook-like projections arranged to be directed into respective ones of said spaced openings in its associated outer structural element whereby it is supported in cantilevered fashion therefrom, said upper projection having its forward edge outwardly curved to provide a first arcuate camming edge wedgingly contacting the inner face of said outer structural element transverse wall, said lower projection having its rearward edge outwardly curved to provide a second arcuate camming edge wedgingly contacting the inner face of said inner structural element transverse wall, each said structural element pivoted at its upper end to its associated bracket, link means pivotally connecting the lower ends of each pair of said structural elements, the pivots of said bracket and the link means of each pair of structural elements being positioned to lie in the four corners of a parallelogram linkage whereby said shelf assembly may be angularly moved from said retracted position to an outer extended position, said support arms first and second arcuate camming edges being shaped to maintain opposed sliding wedged contact with their associated channel faces whereby said shelves are moved into stepped relation in their extended position with no substantial tilting from the horizontal.

2. The combination of claim 1 including electric motor driven stringer linkage actuating means connected to at least one of said linkages for angularly moving said one linkage whereby said shelf assembly will be moved from its retracted position to an extended position.

3. In a refrigerator cabinet comprising wall structure defining a box-like storage compartment provided with a front access opening and a door for said opening, said wall structure including a rear wall and opposite side walls, a shelf assembly including a plurality of horizontally disposed cantilevered shelves supported in said compartment in vertically stacked relation therein by means of first and second spaced apart pantograph-type composite stringer linkages, a bracket for pivotally supporting each said stringer linkage solely from said rear wall of said compartment for travel in a common vertical plane resulting in combined upward and outward movement of said shelf assembly from an inner retracted position to an outer extended position, each said first and second composite stringer linkage being vertically oriented in said cabinet at a corner juncture defined by said rear wall and its adjacent side wall when said shelf assembly is in its retracted position, each said composite stringer linkage including a pair of outer and inner coextensive channels dimensioned to nest in opposed relation to form a box-shaped section, said outer channel having its transverse wall provided with vertically spaced openings therein, each of the shelves having a pair of spaced cantilever support arms, each said support arm rear portion including upper and lower hook-like projections arranged to be directed into respective ones of said spaced openings in its associated outer channel whereby it is supported in cantilevered fashion therefrom, said upper projection having its forward edge outwardly curved to provide a first arcuate camming edge wedingly contacting the inner face of said outer channel transverse wall, said lower projection having its rearward edge Outwardly curved to provide a second arcuate camming edge wedgingly contacting the inner face of said inner channel transverse wall, each said channel pivoted at its upper end to its associated bracket means, link means pivotally connecting the lower ends of said nested channels, the pivots of said bracket and said link means of each being positioned to lie in the four corners of a parallelogram linkage whereby upon said shelf assembly being angularly moved from said retracted position to an outer extended position, said support arms first and second arcuate camming edges being shaped to maintain opposed sliding wedged contact with their associated faces whereby said shelves are moved into stepped relation with no substantial tilting from the horizontal.

4. In a cabinet comprising wall structure defining a box-like storage compartment provided with a front access opening and a door for said opening, said wall structure including a rear wall and opposite side walls, a shelf assembly including a cantilevered horizontally disposed shelf supported in said compartment by means of a plurality of spaced apart pantograph-type composite stringer linkages, a U-shaped bracket for pivotally supporting each said stringer linkage solely from said rear wall of said compartment for travel in a common vertical plane resulting in combined upward and outward movement of said shelf assembly from an inner retracted position to an outer extended position, each said composite stringer linkage being vertically oriented in said cabinet when said shelf assembly is in its retracted position, each said composite stringer linkage including a pair of outer and inner coextensive elongated structural elements, said outer structural element having a transverse wall provided with vertically spaced openings therein, said shelf having a plurality of spaced cantilever support arms, each said support arm rear portion including upper and lower hook-like projections arranged to be directed into respective ones of said spaced openings in its associated outer structural element whereby it is supported in cantilever fashion therefrom, said upper projection having its forward edge outwardly curved to provide a first arcuate camming edge wedgingly contacting the inner face of said outer structural element transverse wall, said lower projection having its rearward edge outwardly curved to provide a second arcuate camming edge wedgingly contacting the inner face of said inner structural element transverse wall, each said structural element pivoted at its upper end to its associated bracket, link means pivotally connecting the lower ends of each pair of said structural elements, the pivots of the bracket means and the link means of each pair of structural elements being positioned to lie in the four corners of a parallelogram linkage whereby said shelf assembly being angularly movable from said retracted position to an outer extended position, said support arms first and second arcuate camming edges being shaped to maintain opposed sliding wedged contact with their associated faces whereby said shelf is moved with no substantial tilting from the horizontal, a linear electric motor within said compartment, flexible control wire means operatively connected to one of said support arms controlled by said motor, door switch means controlled by the opening of said door to energize said motor to move said shelf assembly from its retracted position to an outer extended position.

5. The combination of claim 4 including shelf position control switch means for selectively energizing the windings of said linear electric motor whereby said motor may be reversed to move said shelf assembly either to an extended or retracted position upon the opening of said door.

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