U.S. patent number 3,814,492 [Application Number 05/308,239] was granted by the patent office on 1974-06-04 for cantilever shelf assembly with pantography support arrangement for refrigerators.
This patent grant is currently assigned to General Motors Corporation. Invention is credited to James W. Jacobs.
United States Patent |
3,814,492 |
Jacobs |
June 4, 1974 |
CANTILEVER SHELF ASSEMBLY WITH PANTOGRAPHY SUPPORT ARRANGEMENT FOR
REFRIGERATORS
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.
Inventors: |
Jacobs; James W. (Dayton,
OH) |
Assignee: |
General Motors Corporation
(Detroit, MI)
|
Family
ID: |
23193150 |
Appl.
No.: |
05/308,239 |
Filed: |
November 20, 1972 |
Current U.S.
Class: |
312/273; 312/269;
312/325 |
Current CPC
Class: |
F25D
25/02 (20130101); A47B 46/00 (20130101) |
Current International
Class: |
A47B
46/00 (20060101); F25D 25/02 (20060101); A47b
088/00 () |
Field of
Search: |
;312/214,271,266,269,273,325,268 ;108/59,102 ;211/148 ;248/243 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Gilliam; Paul R.
Attorney, Agent or Firm: Barthel; Edward P.
Claims
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 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.
Description
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 5--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;
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 12 spaced from the shell and having any suitable or
desirable insulating material 13 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 a pair 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 50a
of 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 50b such that its downwardly extending hook has 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 connected and
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 stringers 22, 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.
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 U.S. 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 I-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 by circuit 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 U.S. Pat. No. 3,546,962 issued Dec. 15, 1970 to Ruhala
and assigned to the assignee of the instant application, and
reference may be had to the Ruhala patent for details of a typical
control wire structure. In FIG. 6 the actuator means 90 is shown in
its shelf assembly retracted position wherein the stop member 110
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, it is within the scope of the
invention that a second actuator means could be employed to
simultaneously drive the right hand linkage mechanism 23.
With reference to FIG. 1, a door switch 130 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.sub.1 to line L.sub.2 through conductors 132 and 133
to a shelf position 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 open switch having its
movable contact 140 in open position engaging fixed open contact
141. In 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.sub.2 through a phase shifting capacitor 144 whereby the
linear motor actuator 92 moves upwardly transmitting upward 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 150 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.sub.2 causing the
armature to move downward and power return the shelves to their
retracted position. Therefore it is apparent that 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 contact 152. 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 131. 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.
* * * * *