Note: Descriptions are shown in the official language in which they were submitted.
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APPLICATION FOR UNITED STATES PATENT
SPECIFICATION
"AUTOMATED PART STORAGE AND MACHINING SYSTEM"
BACKGROUND OE~ T~E INVENTION
The invention disclosed and claimed herein pertains
generally to machining systems which employ a single trans-
port device to automatically move unmachined parts or work-
pieces from inventory storage to a machining center, and
to move machined parts from a machining center to a speci-
fied final destination. More particularly, the invention
pertains to systems of the above type wherein a single
transport device is employed to move a part through both a
first and a second part flow loop, the first loop compris-
ing movement of the part between inventory storage and a
machining preparation station and between the machining
preparation station and a final destination, the second
loop comprising movement of the part between the machining
preparation station and one or more machining centers. Even
more particularly, the invention pertains to systems of the
above type wherein the transport device is employed to move
parts through the firs~ loop on standard storing and ship-
ping pallets, and to move parts through the second loop on
pallets which are also employed to selectively support the
parts while they are being machined.
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In certain types of manufacturing operations which involve
the machining of metallic parts, overall operational efficiency
i5 affected, to a very great extent, by the ef~iciency with
which parts are handled and carried as they are moved through
a part flow route. The flow route of a particular part starts
at the initial location of the part in inventory storage, pro-
ceeds to a machining center or the like, where the part is
selectively machined, and ends at some final destination. The
final destination of the machined part may comprise, for ex-
ample, a part inspection station, a finished parts pick-up
station, a truck loading dock, or a location in inventory
which is the same as or dlfferent from the initial location
of the part.
It will be readily apparent that the efficiency of part
flow in a machining or metal cu~ting operation is closely re-
lated to the amounts of time that various devices, which are
used to move parts through the part flow route, are idle. It
may therefoLe be very important, especially in operations
which produce a comparatively small number of parts in a
~o pexiod of time ~low-volume and mid-volume production) to limit
the number of separate devices which are employed to transport
parts through the part flow route, and to maximize the cap-
abilities of the devices which are employed therefor. In ad-
dition to reducing idlin~ time of the part transporting equip-
ment, such limitation may serve to reduce plant space require-
ments and also the level of maintenance which is required for
part transport equipment.
In order to significantly improve part flow efficiency in
a machining operation, the present invention provides a com-
prehensive machining system, or cell~ wherein a single de~ice
is used to perform all or most of the handling and transport-
ing i~asks which are required to move parts through the part
flow route of the system. It is anticipated ~hat an embodi-
ment of the invention could usefully be employed to machine
parts in the low and mid-volume ranges of part production,
altho~gh it is by no means intended to limit the invention
to such application. It is further anticipated that the in-
vention may provide a system which may be operated in a com-
pletely automatic mode to move parts from an inventory stor-
age to a machining center, and to move machined parts either
back to inventory or to a system part exit point.
SUM~ARY OF THE INVENTION
In the present invention, a machining system is provided
which includes a storage structure having a number of discrete
part storage locations. The system further includes a number
of work units which are located proximàte to the storage
structure, for selectively machining parts. A part prepara-
tion station is located proximate to the storage structure
for enabling a system operator to prepare a part, received
from one of the part storage locations, for processing or ma-
chining by one of the work units. The system employs a single
transport device to sequentially move a given part from one of
the storage locations to the part preparation station, from
the part preparation station to one of the work units, and
from one of the work units to a selected final destination
which is proximate to the storage structure.
Preferrably, the storage structure comprises a vertically
~5 oriented rack structure provided with a number of discrete
addressable bins, each of the bins comprising one of the part
storage locationsO Preferrably also, the part preparation
station includes a part preparation shuttle for moving the
given part between the part transport device and a selected
location within the part preparation stationt the part trans-
port device comprising means for selectively engaging a stor-
ing and shipping pallet and a machine pallet. The part trans-
port device moves the given part from one of the storage bins
to the part preparation shuttle, and from -the part pre-
paration shuttle to the final des-tination, upon the
storing and shipping pallet,and moves -the given part
between the part preparation shuttle and one of -the
machining centers upon the machine pallet. The part
preparation s-ta-tion comprises a means for enabling a
system operator -to transfer -the given part be-tween
-the storing and shipping palletand the machine pallet
with comparatively little effort, and in a short period
of -time.
In a preferred embodimen-t of the invention, each
of the work units comprises a machining cen-ter Eor per-
forming specified metal cut-ting opera-tions. The par-t
transpor-t device comprises a s-tacker crane which is
constrained to move linearly along one side of the rack
struc-ture, the part prepara-tion sta-tion being located
on the o-ther side of the rack struc-ture. The part pre-
paration shuttle includes a first shu-ttle device which
traverses a gap in -the rack structure -to move a s-toring
and shipping pallet, and a part carried thereupon,
between the stacker crane and an operator posi-tion in
the part preparation station. The par-t prepara-tion
sta-tion also includes a second shut-tle device, which
likewise traverses -the rack s-truc-ture -to move a machine
pallet and a part thereupon between -the s-tacker crane
and the opera-tor position. First and second air s-ta-
tions, of different configurations, are respectively
employed in -the firs-t and second shut-tle device to
enable both types of pallets, andparts-thereupon, to be
moved into and out of the part preparation station
with a minimum amount oE effor-t.
FEATURES OF THE INVENTION
The invention seeks to optimi~e the efficiency
with which parts are moved -through a part processing
sys-tem, wherein parts must be moved from inventory
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storage to a processing unit, such as a machine tool or
machining center, and must thereafter be moved either
back to inventory storage or to a poin-t at which pro-
cessed par-ts exit the system.
~ `he invention also seeks -to minimize the equip-
ment which is required to handle and move parts in a
system of the above type, and also to minimize -the idle
time of such equipment.
Still further the inven-tion seeks to provide a
system of the above -type wherein a single device, such
as a s-tacker crane, is employed to move par-ts between
inventory storage and the processing units, and between
the processing units and the part exit poin-t.
The invention also seeks to provide a comprehensive
machining system or cell which includes a par-ts inven-
tory storage, a number of machining centers, efficient
means for moving parts between inventory storage and -the
machining centers, and means for maintaining close
inven-tory con-trol of all parts con-tained in the system
as they are s-tored, moved and machined.
Still further the invention seeks to provide a
machining sys-tem of -the above type wherein par-ts are
moved on machine pallets, on which they are set up for
machining, and on storing and shipping pallets of a
type which are commonly used both to store metal parts
in inventory and to ship them in comrnerce.
The invention also seeks to provide a machining
system of the above type which may be operated in a
fully automatic mode, wi-thout the intervention of a
human opera-tor, to machine a number of parts in a pre-
specified manner.
BRIEE DESCRIPTION OF THE DRAWINGS
Figure 1 is an o~erhead view showing the princi-
pal components of an embodimen-t of the inven-tion and
the relationships therebetween.
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Fig~ 2 is an elevational view showing a stacker crane
and a storage rack structure for the embodiment of Fig. 1.
Fig~ 3 is a perspective view showing t~e principal com-
ponents of a wood pallet air station for the embodiment of
E~ig. 1.
Fig. 4 is a perspective view showing the underside of an
air pallet for the wood pallet air station of Fig. 3.
Fig. 5 is an overhead view of a cam roll of the air pal-
let of Fig. 4.
Fig. 6 is a sectional view showing the operational rela-
tionship between a stacker crane and the wood pallet air sta-
tion of Fig. 3.
Figs~ 7-9 are sectional views showing the operation of
airbags to support the air pallet of Fig. 4 on an air table.
Fig. 10 is a perspective view showing the principal com-
ponents of a machine air pallet for the embodiment of Fig. 1.
Fig. 11 is a perspective view showing a switch for the
machine air pallet of Fig. 10.
Fig. 12 is a sectional view showing the operational re-
lationship between the stacker crane and a machine pallet air
station employing the machine air pallet of Fi~. 10.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to Figure 1, there is shown a combined machin~
ing and inventory storage system 10, which is provided with
a number of machining centers 12 and with storage rack struc-
tures 14a and 14b. Each machining center 12 comprises a ma-
chine tool or machining centerl such as the MILWA~KEE-MATIC
800 manufactured by the Kearney & Trecker Corporation, which
may be directed by either an operator or a remotely located
computer device to perform a succession of machining opera-
tions on a metallic part which has been presented to the cen-
ter. It is to be noted that "MILWAUKEE-MATIC" is a registered
trademark of the Kearney & Trecker Corporation.
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Rack structure 14a and 14b each comprises a number of
storage bin colum~l6, which are linked together, in linear --
~relationship, along a linear track 18~ Each column 16 com-
prises a number of discrete, vertically stacked storage bins,
each bin being identifiable by its vertical level and by its
position along track 18. Each bin has an opening which faces
track 18, and the bins are sized so that they may receive and
store parts which are entered into system 10 for machir ~g by
machining centers 12. Some of the bins of the rack structures
may also be employed to store fixtures which are used to set
paLts up for machining by the machining centers. All of the
parts and fixtures in the storage bins are stored on wooden
pallets, such pallets being of a type which is widely used
to store metallic parts in inventory, to move parts around a
plant or factory by means of a fork lift, or to ship or trans-
port parts in commerce.
To insert parts into and draw parts out of the storage
bins of rack structures 14a and 14b, and to move parts around
system 10 in support of the machining operations thereo~l sys-
2~ tem 10 is provided with a stacker crane 20. Stacker crane 20
comprises a type of device which is well-known in the storage
~nd wareho~sing arts, and which is commonly used therein to
move goods into and out of identifiable, vertically oriented
storage bins. While specific details of the construction of
stacker crane 20 may vary in accordance with specific appli-
cations, generally the stacker crane is provided with the
capability of moving linearly, along the length of track 18
and of stopping at any point therealong. The stacker crane
is further provided with a transverse member mounting a set of
lifting forks 22, which ma~ be controllably moved upwardly and
downwardly, and which may be extended outwardly from, and be
drawn inwardly toward the center line of track 18. Respective
components of stacker crane 20 are sized or dimensioned so
that the stacker crane can be directed to any of the storage
bins of storage racks 14a and 14b, and can employ its lifting
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forks 22 to insert thereinto or to retrieve therefrom a wooden
pallet which bears or carries a partr parts or fixtures.
Stacker crane 20 can also be directed to an end of track
- 18 at which a part loading station 24a and a part exit station
24b are located. Station 24a comprises a point at which un-
inished parts are received into system 10, upon wooden pal-
lets, and station 24~ comprises a point at ~hich parts leave
the system after they have been completely machined. The
lifting forks of stacker crane 20 may be employed to receive
wooden pallets containing parts at the part loading station,
and to deliver wooden pallets containing parts to the part
exit station.
Referring further to Fig 9 1, there are shown machining
centers 12 located at the end of track 18 opposite from s~a-
tions 24a and 24b, each machining center 12 being provided
with a machine pallet 26.
As is well known in the art, a machine pallet is a sturdy,metallic base or platform, which is employed to support a part
in rigid relationship with the spindle of a machining center
as the spindle drives a tool to selectively cut or machine
the part. Stacker crane 20, in addition to the above cap-
abilities, is capable of moving along track 18 to a specified
one of the machining centers 12, and of operating its lifting
forks 22 to enyage the machine pallet 26 of the specified
center. The stacker crane is then moved back along track 18
to a part preparation station 28. An aiL pallet 30 of the
pa~t preparation station, described hereinafter in detail1 is
movable through a gap or opening provided in rack structure
14a to receive the machine pallet 26 from the li~ting forks
of the stacker crane. The machine pallet is then moved into
the part preparation station upon the air pallet 30.
In a like manner, stacker crane 20 may be operated to re-
ceive a machine pallet 26 from an air pallet 3~, and to return
the machine pallet to its machining center. A machining cen-
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ter may employ a shuttle device of conventional design (not
shown) to transfer its machine pallet between the lifting
forks of the stacker crane and the working or operational
position of the machine pallet on the machining center.
Referring yet again to Fig. 1, there are shown air pal-
lets 32a and 32b at each preparation station 28 which, in
like manner with ~ir pallets 30, are accessible to stacker
crane 20 through selectively positioned gaps in rack struc-
ture 14a. Air pallets 32a, described hereinafter in detail,
are provided to receive wooden pallets which bear parts or
fixtures from stacker crane 20, and air pallets 32b are pro-
vided to convey or deliver such wooden pallets to stacker
crane 20.
The movement and operation of stacker crane 20 may be
selectively directed by a human operator, by a local computer
carried aboard the stacker crane, or by a system computer 34,
which is also capable of remotely operating each of the ma-
chining centers 12. In addition, system computer 34 keeps
track of the location of every part cont3ined in system 10,
at all times, and maintains a record of the machining per-
formed on each part. Computer 34 also uniquely identifies
or addresses each of the bins or storage locations of storage
racks 14a and 14b.
In order to perform a specified set of machining opera-
tions upon a part of a particular type, stacker crane 20 is
directed, by one of the above means, to retrieve a part of
the particular type from its storage bin, and to deliver such
part, upon its wooden pallet, to the air pallet 32a of one of
the part preparation stations 28. The part, wooden pallet,
and air pallet 32a are then linearly translated over, or
along, an air table 36. At the same time, stacker crane 20
is ~ispatched to retrieve a fixture from one of the storage
bins which corresponds to parts of the particular type.
Ea~h air table 36 comprises a smooth, rigidly supported
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horizontal surface, one end of which is accessible to stacker
crane 20, through a gap in rack structure 14a, and the other
end of which abuts a linear conveyor 38, which is provided
with powered rollers 40. Air pallet 32a is moved or trans-
lated over an air table 36 by means of a drive chain 42, which
is connected to the air pallet 32a through a slot 44 provided
in the air table. As pallet 32a is translated, an array of
airbags on the underside thereof are maintained in an inflated
condition to provide a cushion or film of air between the air
pallet 32a and the table 36. Such air cushion is sufficiently
strong to support the combined weight of an air pallet 32a
and a part and a wooden pallet carried thereby, whereby fric-
tion between the air pallet 32a and the horizontal surface of
the air table 36 is virtually eliminated. An air pallet 32a
and table 36 together comprise a wood pallet air station 46a.
Each air pallet 32b of Fig. 1 is identical to an air pal-
let 32a, and is likewise supported upon and moved over an air
table 36. An air pallet 32b and a table 36 together comprise
an air station 46b.
When the air pallet 32a reaches the end of air table 36
which abuts conveyor 38, freely turning rollers 48, which
are mounted upon the air pallet 32a to carry a part and its
wooden pallet, are brought into aligned relationship with
powered rollers 40. While in movement, an air cell brake 49
prevents the rollers from turning freely. A human operator may
then, with little effort, slide the part and wooden pallet on-
to rollers ~0 from the air pallet 32a, and activate conveyor
38 to move the part and wooden pallet to an operator position
50, within the part preparation station. At the same time,
the pallet 3~a is translated back toward rack structure 14a,
to receive the aforementioned corresponding fixture from the
stacker crane. Air station ~6a and conveyor 38 are then operated,
as aforedescribed, to move the fixture, upon its wooden pallet
to operator position 50~
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After delivering the corresponding fixture to the air
station 46a, stacker crane 20 is moved along track 18 to the
machining center 12 which is to perform the aforementioned
specified set of machining operations. The stacker crane en-
gages the machine pallet 26 of such center, and delivers itto an air pallet 30 of the part preparation station 28 to
which the aforedescribed part and fixture have ~een delivered.
The operator then manually draws or pulls the air pallet 30
into the part preparation station, over or across an air
table 52, to operator position 50. Air table 52 comprises a
smooth riyidly supported horizontal furface, one end which
is accessible to stacker crane 20 through a gap in rack struc-
ture 14a, and the other end of which is proximate to operator
position 50. As with air pallets 32a and 32b, when air pal-
let 30 is translated over air table 52, an array o~ airbags
on the underside of pallet 30 is inflated to maintain a
cushion or film of air between the pallet 30 and the table
52. Such cushion is suf~iciently strong to support the com
bined weight of the air pallet 30 and a machine pallet car-
ried thereupon, whereby an operator, with comparatively littleeffort, may translate a pallet 30 backwardly and forwardly
over an air table 52. An air pallet 30 and an air table 52
together comprise a machine pallet air station 54.
It is to be noted that an operator positioll 50 comprises
any location within a part preparation station 28 to which a
part, a fixture corresponding thereto, and a machine pallet
can be brought into closely spaced relationship, by the co-
ordinated operation of an air station 46a, an air station 54
and a conveyor 38. When all of such elements are together in
an operator position, a human operator may, with minimum
physical movement, take the ~ixture from its wooden pallet
and secure it to the machine pallet~ The operator may then
employ the fixture to attach the part to the machine pallet
so that the part is fixed in a position and orientation,
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relative to the machi.ne pallet, which is required by the
specifications o the machining operations which are to be
performed.
If the part is comparatively heavy, the operator may
employ an underhung bridge crane 55 to transfer the part from
its wooden pallet to the machine pallet 26.
When a part has been joined to a machine pallet 26 as
required for machining, the part is set up, and the machine
pallet is said to be "loaded". The loaded machine pallet 26
is moved backwardly along air table 52r by manual translation
of air pallet 30, and is engaged by lifting forks 22 of stacker
crane 20. The stacker crane takes the loaded pallet 26 back
to its mathining center 12; whereupon the machining center,
under the control of either a machine operator or system com-
puter 34, performs the required set of machining operations.
After the part has been machined, the loaded machine
pallet is returned to operator position 50 by the coordinated
operation of stacker crane 20 and air station 54. The fixture
and thenewly machined part are replaced upon their respective
wooden pallets, and air station 54, conveyor 38, air station
~6b and stacker crane 20 are respectively employed to return
the machine pallet 26 to its machining center, to return the
fixture to a storage bin, and to move the machined part to a
specified final destination~ Such final destination may com-
prise one of the storage bins, a finished parts inspection
station 58, part exit s~ation 24b, or a manually operated mil-
ling or metal cutting machine 60. Air stations 46a and shor-
tened air stations 46b, situated in gaps or openings in rack
structure 14b, are provided for moving parts between stacker
crane 20 and inspection station 58 and machines 60.
It will be seen from Fig. 1 that two part preparation
stations 28 are situated in adjoining relationship with one
another~ A single operator is thereby enable~ to move back ~--
and forth between the stations 28, with a mini~um o~ wasted
e~fort, to service both stations in setting up parts ~or ma-
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chining. The number and location of part preparation sta-
tions 28 which is most efficient for a partic~lar application,
as ~ell as the num~er of machine pallet air stations 54 pro-
vided in each part preparation station, will be related to
the time req~ired to machine parts and to move them aro~nd
system 10 in the particular application.
Referring once more to Fig. 1, there is shown a coolant
trough 62 place~ beneath each machining center 12 so that metal
chips and coolant, generated by metal cutting activity, are
directed into trough 62 by means of gravitational force. The
need for chip conveyors in system 10 is thereby eliminated.
Referrins to Fig. 2, there is shown rack structure 14a
comprising a number of storage bin columns 16, wherein each
column 16 comprises a number of vertically stacked storage
locations, or bins 64. Each bin 64 is a part storage space
which is bounded by the sides 66 of its column 16 and by wood
pallet support brackets 68. The brackets 68 which are posi-
tioned at the bottom of each storage bin 64 are capable of
supporting a wooden pallet 70 of the aforedescribed type, as
well as a part 72 or a fixture 74 placed thereupon. The op-
posing bottom brackets 68 of a storage bin are spaced apart
from one another so that by selective movement of stacker crane
20, and by selective manipulation of the transverse member 75
thereof, lifting forks 22 may be positioned between the op-
posing bottom brackets, either to place a wooden pallet 70
thereupon or to remove a wooden pallet 70 therefrom.
Referring further to Fig. 2, there are shown gaps or
openings provided through some of the columns 16 of rack
structure 14a to allow wooden pallets 70 carr~ing parts 72
and fixtures 74 to be exchanged between stacker crane 20 and
air stations 46a and 46b, and to enable machine pallets 26,
and parts set up thereupon, to be exchanged between stacker
crane 20 and air stations 54.
Re~erring to Fig. 3, there is shown an air pallet 32a
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(or 32b) supported upon an air table 36 and translatable
therealong, as afore~lentioned, upon a ~ilm or cushion of air.
510t 44, running nearly the length of air table 36, allows a
pneumatic line 76 to remain coupled to air pallet 32a as air
pallet 32a is translated over table 36. Air line 76 is em-
ployed to inflate each of a number of airbags attached to the
underside of air pallet 32a, to generate and maintain the
aforementioned cushion or film of air between the flat s~r-
face of table 36 and the underside of air platform 32a.
Referring further to Fig. 3, there are shown guide blocks
78 joined to the underside of air pallet 32a. Guide blocks
78 are sized or dimensioned to fit into slot 44, and are pro-
vided to prevent lateral or sideward movement of air platforn~
32a as air platform 32a is linearly translatea over air table
36. C-channels 79 run along the sides of table 36 to support
wooden pallets received from stacker crane 20.
To enable an operator tc easily control the operation of
an air station 46a ~v. 46b), a unitized control box 80 is pro-
vided therefore. A control switch 82 of box 80 enables the
operator to selectively open and close air line 76, to respec-
tively inflate or deflate the airbags attached to the under-
side of air pallet 32a. When the air bags are inflated, a
control switch 84 is emplo~ed to selectively operate drive
chain 42 to translate air pallet 32a forwardly or backwardly
over air table 36~ Control switch 84 can be operated whether
switch 82 is engaged or not. Drive chain 42 is coupled to
air pallet 32a through slot 44 as aforementioned, and is
powered by a drive train located underneath table 36. The
drive chain 42 and drive train may be of any suitable design
occurring to those of skill in the art, and are not shown in
Fig. 3.
Referring to Fig. 4, ~here is shown airbags 86 positioned
in a selected array on the underside of air pallet 32a, each
airbag comprising an annular diaphragm which is formed o~
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flexible rubber or like pliable material. Air line 76 is
coupled to the interior of each airbag 86 50 that the airbags
are inflated or deflated when the line is respectively opened
or closed. Fig. 4 also shows a center landing pad 88 posi-
tioned in the center of each airbag 86, and shows corner rol-
ler 90 positioned at each corner of the underside of air pal-
let 32a. Landing pads 88 and rollers 90 are provided to sup-
port air pallet 32a upon air table 36, in spaced apart rela-
tionship therefrom, when the airbags are in a deflated condi-
tion. Such spaced apart support protects deflated airbags 86from metal chips or like debris which might be lying on air
table 36.
Usefully, air bags 86 comprise a type of product such as
that which is manufactured by Aero-Go Inc., and which is iden-
tified thereby as the "aero-Caster" load module on air bear-
ing. It is to be noted that "Aero-Caster" is a registered
trademark.
Referring further to Fis. 4, there is shown guide blocks
78 provided with rollers 92, which are formed of material such
as hard rubber or the like. Rollers 92 abut the sides of slot
44 when cam rolls 78 are placed therein, and are provided to
minimize friction between the guide blocks and the sides of
slot 44 when air pallet 32a is translated over air table 36.
Referring to Fig. 5, there is shown rollers 92 rotatably
mounted within recesses provided in guide bloc~s 78 by means
of pins 94.
Referring to Fig. 6, there is shown lifting forks 22 of
stacker crane 20 placing a wood pallet 70l together with a
part 72 carried thereupon, upon C-channels 79 which pass into
one of the aforementioned gaps in rack structure 14a. Fig.
6 further shows an air pallet 32a positioned directly beneath
pallet 70l the air bags oE the air pallet 32a being in a de-
flated condition. Air pallet 32a is thereby supported upon
air table 36, at the extreme end thereof, upon center landing
pads 88 and corner landing pads 90.
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T~ load the wooden pallet 70 and part 72 upon the air
pallet 32a, li~ting forks 22 are withdrawn~ Then, air line
76 is opened to inflate each of the air bags 86, whereby the
airbags generate zones of compressed air. Such air zones,
which together comprise the aforementioned cushion or film of
air! raise air pallet 32a upwardly from air table 36, whereb~
air pallet 32a lifts the wooden pallet 70 and part 72 off of
brackets 68. Air pallet 32a, pallet 70 and part 72 may then
be translated along air table 36.
Referring to Fig. 7, there is shown air bags, or annular
diaphragms 86, in a deflated condition, air line 76 being
closed. As in Fig. 6, air pallet 32a is shown supported on
air table 36 by means of center landing pads 88 and corner
landing pads 92
Referring to Fig. 8, there is shown diaphragm 86 being
inflated by air received through air line 76, the diaphragms
being coup~ed to air line 76 through conduits 96. As the
diaphragms are inflated, the outer portions thereof initially
remain in contact with air table 36, forming closed plenum
chambers 98. Small openings are provided around the inner
edges of the annular diaphragms, enabling air under pressure
to flow into the plenum chambers 98 from the air bags or dia-
phragms 86.
When the air pressure in the plenum chambers 98 becomes
sufficiently great, air is force out of the chambers, beneath
the air bags 86 r and pallet 32a is raised upwardly from air
table 36, to a height which is on the order of several thous-
andths of an inch. Referring to Fig. 9, there is shown air
pallet 32a in such raised condition, such condition being main-
tained as long as air line 76 remains open.
Referring to Fig. 10, there is shown an air pallet 30
comprising a lower platform 100 and an upper platform 102,
both platforms 100 and 102 having arrays of air bags 86 on
their respective undersides which are similar or identical
to the aforedescribed airbag arra~ on the underside of air
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pallet 32a. When the airbags on the underside of lower
platform 100 are inflated, a cushion of air is generated
which raises air pallet 30 upwardly from its air table 52,
enabling ~ human operator to easily translate air pallet 30
over its air table. A hand grip 104 is joined to lower plat-
~orm 100 for the use o~ the operator in performing such
translations. To prevent lateral motion of air pallet 30 as
it is being translated, guide blocks 106 are placed upon the
~nderside of platform 100. Guide blocks 106, which are simi-
lar or identical to guide blocks 78, are sized to fit into aslot which runs along the length of air table 52
Referring further to Fig. ~0, there is shown a pin 10
which joins upper platform 100 and lower platform 102 to-
gether J in pivotable relationship. Consequently, when ~he
~5 airbags on the underside of paltform 102 are inflated raising
platform 102 upwardly from platform 100, platform 102 may be
easily indexed or rotated by a human operator, relative to
platform 100. It has been found that by providing air pallet
30 with such indexing or rotating capability, the efficiency
with which an operator can lOâd a machine pallet 26, posi-
tioned upon air pallet 30, may be significantly enhanced.
Referring again to Fig. 10, there is shown a machine
pallet support structure 110 rigidly mounted upon the upper
surface of platform 102. Structure 110 is provided to receive
a machine pallet 26 from stacker crane 20, and to rigidly sup-
port the machine pallet when the air pallet 30 is translated
over an air table 52 and when the machine pallet is being
loaded with a part and a fixture. Machine pallet retention
pads 112 are placed upon structure 110, and are selectively
spaced apart so that a machine pallet 26 placed upon struc-
ture 110 will fit therebetween. At the same time, the ma-
chine pallet will be prevented by retention pads 112 frommoving for~ardly or backwardly along structure 110.
Referring to Figs. 10 and 11 together, there is shown
a switch 114, enclosed within hand grip 104, which may be
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moved outwardly from and inwardly toward pallet 30 by an
operator, and which may be retained in one of three positions
by n otches 114a-c. When the switch is retained in a posi-
tion by notch 114a, the airbags 86 on the undersides of both
platforms 100 and 102 are deflated. When the switch is re-
tained in a position by notch 114b, the airbags 86 on the
underside of platform 100 are inflated, to enable translation
of air pallet 30 over an air table 52~ ~t the same time, the
airbags of platform 102 are in a deflated condition, to pre-
vent indexing thereof relative to platform 100. When the
switch is retained in a position by notch 114c, the air bags
of platform 102 are infalted, allowing indexing thereof, and
the airbags of platform 100 are deflated, preventing transla-
tion. It will be seen that by providing switch 114, a machine
pallet 26 on air pallet 30 cannot be both translated and ro-
tated at the same time. An operator in a preparation station
28 is thereby provided with a heightened degree of control
over movement of a machine pallet upon an air pallet 30.
Referring to Fig. 12, there is shown an air pallet 30
located at the extreme end of an air table 52, beneath a
column 16, to receive a machine pallet 26 from liftin~ forks
22 of stacker crane 20. There is further shown an air line
116 passing upwardly into pin 108 to provide air for inflating
airbags 86 of platforms 100 and 102. Air pallet 30 is shown
in Fig. 12 supported upoh center landing pads 88 and corner
landing pads-118.
In a modification of the above embodiment, a number of
machine pallets could be loaded with parts and fixtures, and
then be stored in rack structures 14a and 14b. Stacker crane
20 and machining centers 12 could then be operated automtical-
ly, under the control of system computer 34, ~ move and ma-
chine the parts without any involvement of a human operator.
Obviously, many other modiflcations and variations of
the present invention are possible in light of the above
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teachings, and it is therefore understood that within the
scope of the disclosed inventive concept, the invention may
be practiced otherwise than as specifically described.
