Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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The present Inventlon relates to a vacuum-grlp cuttlng
table.
There are many patents dlrected to the cuttlng of tex-
tlles or slmilar materlals on fixed tables on whlch the materlalsare held In place by a vacuum. Because of the dlmenslons of the
materlal to be cut (large lengths) moblle tables were provlded
whlch feed the materlal, so operatlon by sectlons, thus prevent-
lng cuttlng dlmenslons whlch are the same as or larger than those
of the materlal to be cut. Wlth thls system, the means of vacuum
grlp cannot b0 of such slmple deslgn as Is the case wlth a sta-
tlonary table. The problem of sealln~ the movlng parts led to
the complete encloslng of the conveyor table In a hermetlcally
sealed "drawer" leavlng the top part open. Once the fabrlc Is In
place, It Is closed by some Impermeable material whlch does not
allow the passage of alr and Is normally thrown away once It has
been plerced by the cuttlng blade. Appllcatlons of thls technol-
ogy are to be found In the GERBER GARMENT TECHNOLOG~ INC. S~ ;5
patents Nos, 520,922, 520,923 and 520,924 and STUMPF Vn;t~ 5
patent No. 4,322993.
One of the dlsadvantages of the sald system Is the
sturdlness requlred for the drawer, slnce the vacuum levels used,
and the relatlvely large areas, glve rlse to very hlgh forces ~of
some tons).
Other solutlons whlch have been developed Include the
construction of a hermetlcally sealed chamber under the cutting
table surface whlch, through valves, communlcates wlth separate
sectlons, as In the Gerber Spanlsh patent No. 506,931. A sult-
able synchronlsm ensures that the open valves provlde a vacuum to
thé area of the materlal on whlch the cuttlng tool Is worklng.
Thls method only partly solves the problem, slnce the sectloned
area under vacuum must be large enough to cover an area of the
3~ matertal whlch ensUres tha~ It Is held fast In splte of the
actlon of the cutter. Thus, h I gh load leveis must be sustalned.
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Subsequent work led to increased sectioning of the area of
the vacuum, and the cutting table became overcomplicated; see
Gerber U.S. patent Nos. 4,485,712 and 4,528,878.
The present invention provides a simple solution of the
vacuum application, which does not create large sealed
chambers nor does it r~quire sectioning, so that construction
is dramatiFally simplified
According to the present invention there is provided a
vacuum-grip cutting table having mean~ to connect a vacuum
from a stationary source to a mobile table, a cut being
effected by successive sections of a stack of a flexible
material which is moved forward by the mobile table, said
means comprising a central suction pipe which is attached to
a frame and which is hermetically sealed except on a top side
thereof,.wherein there are holes aligned with a further set
of holes in the bottom of tubes or tiles located at right
angles thereto and which are driven by chains, to form a
: ~ supporting base of a penetrable surface which is permeable to
: air and on whic~ the material to be worked is placed, and
means for preventing side leaks between upper side surfaces
of the central pipe and shorter sides of said tubes or tiles
whereby a seal is created between longitudinal sides of said
tube~ or tiles and the penetrable surfacel since the vacuum
generated inside only reaches the penetrable surface through
holes made therefor, and from there to the top face where the
fabr~c is in place, and the fabric is secured due to the :
difference in atmospheric pressure, and the vacuum created in
the penetrab].e surface.
: Thus:, the present invention provides the devices
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xequired to deliver the vacuum to a conveyor table where the
strip material to be cut with a numerically controlled
machine is held in place~
In one embodiment of the present invention the table
includes a plastic strip witA a low friction coefficient
located
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on the top surface of the central suctlon plpe, whlch has a set
of holes In llne wl~h those on the sald plpe, and on whlch the
tlles sllp. Deslrably to prevent vacuum loss In the llnk between
the flxed Plpe and the movln~ tlles, rubber strlps are fltted
onto the central plpe, In contact wlth the plastlc support strlp,
and whlch rub on ~he bottom surfaces of the tlles and so guaran-
tee a hermetlc seal, together with the pressurlzed seal formed by
the tlle support on the plastlc strlp.
In another embodlment of the present Inventlon the
arrangement of holes In the central suctlon plpe Is such that,
for any posltlon of the moblle table, there Is a compiete or par-
tlal alIgnmen~ between these holes and those In the undersldes of
the tlles, the dlstance between the holes In the plpe belng less
than thelr length, and the length of the holes In the tlles also
belng the same. Sultably a contlnuous slot In ~he central suc-
tlon plpe ensures the complete Flow of alr through the holes In
the tlles. DesIrably plastlc gaskets are fl~ted between the
plpes formed by the tlles, fIxed or housed In thelr sldes, at
rlght angles to the dlrectlon of movement, to prevent the entry
of alr from outslde the loop In the dlrectlon of the penetrable
surface. Sultably the ends of the tlles are rlgld parts whlch
hermetlcally seal the plpes and on whlch gaske~tIng Is fItted to
prevent alr from enterlng from the sldes of the table In the
~2~ directlon of the penetrable surface. Preferably the end sectlons
are made of plastlc foam whlch, when compressed between one tlle
and another, seal off the admlsslon of alr.
In speclflc terms, the table Is of the type made up of
3Q a successlon of tlles connected to the llnks In two chalns (or
group thereof) whlch are closed and sllp or run on guldes and
mesh at least on two toothed wheels whlch provlde the movement.
On the upper surface of the loop formed by the successlve tlles,
; a brldge runs wlth supports and dlsplacement devlces of Its own
whlch provlde It wlth movement In the same dlrectlon as the con-
veyor. On thls brldge, a carrlage runs whlch has the tools
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requlred for worklng the matçrlal. In order to secure the strlp
materlal, a vacuum Is applledt In accordance wlth the subJect of
thls Inventlon, under the worklng sur~ace whlch l~ formed by the
conveyor's U~Per face. The sald vacuum Is communlcated to each
of the tlles, whlch are hermetlcally sealed enclosures wlth out-
lets only on the surfaces outslde the loop formed by the con-
veyor.
The presen$ Inventlon wlll be further Illustrated by
way of the accompanylng drawlngs, In whlch:-
Flgure 1 Is a top perspectlve vlew of a cuttln~ machlneof the type to whlch thls Inventlon applles;
Flgure 2 Is a detall of the X-Y axls transmlsslon ele-
ments;
FIgure 3 Is a dlagrammatlc proflle vlew of Flgure 1;
Flgure 4 Is a detall of the moblle table;
Flgure 5 Is a detall of ~he sectlon In whlch the vacuum
Is dellvered to the cuttIng zone;
Flgure 6 Is a sectlonal vlew o~ the moblle tlles;
Flgure 7 Is a perspectlve vlew of ~he tlles, wlth
another deslgn for the end seal; and
Flgure 8 Is a dlagram of the general pressure dlstrlbu-
tlon.
~eferrlng to Flgure 1, from a spreadlng table 5, the
stack of str!p materla~ 12 Is fed by ~he conveyor 14. The cut
panels 18 are wlthdrawn at zone 16 and, as well, at the adJacen~
section of the conveyor. The geome~ry of the cut Is obtalned by
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movement of the brIdge 20 or X carrlage, and the Y carrlage 22.
A controller 24 handles these movements, driving the motors of
the X and Y carrlages. The carrlage 22 has a sultable cuttlng
tool for the materlal to be worked whlch, as can be seen from
Flgure 2, Is dlrected on guldes 26. Thls Flgure a 150 shows the
drlve motor 28 and ~he belt whlch transmlts the movement 30.
Three motors are to be found In thls carrlage, namely the blade
drlve motor, tha~ ~or allgnlng the blade In the tangentlal dlrec-
tlon on the cutting llne, and the sharpenlng motor. The X axls
carrlage Is dlrected on the guldes 32 and It~ motor 34, moored on
the frame, moves the brldge by means of belt 36. The Interactlon
between the cut and the table movement descrlbed In aPpllcant's
Spanlsh patent No. 541,~26 Is brlefly descrlbed by way of contln-
uatlon.
The conveyor Is dlvlded Into three sectlons> as can be
seen In Flgure 3, namely a feed zone 38, a cuttlng zone 40 and a
collectlon zone 42. The materlal Is spread In advance on a table
5 In whlch holes ~or the adm~sslon of pressurlzed alr facllltate
the sllppage of the materlal In the dlrectlon of the cuttlng
machlne. After cuttlng the panels whlch are whole in the cUtting
zone, beglnnlng at the polnt of the X=0 abs~clssa, the conveyor,
drlven by a motor 44 can move along the mlnlmum absclssus, corre-
; spondlng to the next panel to be cUt, and whlch was not wholly
wlthin the cuttlng~wlndow 40. The prevlously cut sectlon ofmaterlal will be In zone 42 whlch contInues to a collectlon table
16.
The Panels furthest from the cuttlng zone wlll be col-
lected, and, when the brldge Is close to the maxlmum absclssus,
those;whlch are closest> for reasons whlch wlll be explalned
beiow. The connectlon~between tables 16 and 5 wlth the conveyor
Is by means of combs 46>~whlch provlde a smooth transltlon In
feed and collectlon.
Fl~ure 4 shows the conveyor table (for clarlty> the
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loadlng and unloadlng tables are not shown, nor are the X car-
rlage drlves and guldes).
The chaln of tlles 48 Is shown, flxed to the chaln 50
whlch Is gulded on a sultable sectlon, preferably of plastl G
materlal for elImlnatlon of frlctlon and nolse. The wheels 54,
drlven by motor 44, move the chalns In accordance wlth the orders
and data from the controller, whlch follows the worklng sequence
prevlously descrlbed. An optlcal codlfler 56 secured to the
shaft glves on-golng Informatlon on the exact posltlon of the
chaln so that, by comparlson agalnst the slgnal from the codlfler
whlch Is Incorporated into the X carrlage drlve motor 34, the
relatlve posltlons of the brldge and conveyor wlll be avallable.
Flgure 5 shows detall of the constructlon of the tlles
48, along wlth the vacuum communlcatlon system whlch malntalns
the materlal to be worked In place under atmospherlc pressure,
whlch Is the baslc purPOse of thls Inventlon. The tlles are made
up of a hollow tube 58 whlch Is hermetlcally sealed at the ends
by sectlons 60; on the underslde there Is a large openlng 62 and,
on the upper surface, a varlety of holes whlch connect wlth
blocks of brls~les or mats whlch are permeable to alr 64.
Flgure ~ shows the detall of a preferred connectlon
2~ between the sald tube and mats; wlth thls system, by extractlng
the end sectlon 60, the mats can be removed. The drlll hoies 59
and the base 61, permeable to alr, are shown. The successlon of
the sald blocks forms the worklng surface whlch, In thls case, Is
a surface whlch can be penetra~ed by a cuttlng blade.
The tube 66 Is secured In the conveyor; wlth the appro~
prlate connectlons, It llnks wlth the vacUum generate~ by pump
68. On the upper face of tube 56, a strlp o~ plastlc materlal 70
Is flxed, wlth low frtctlon and wear rates. Tube 66 and strlp 70
have wlde openlngs 72 dellverlng the vacUum through holes 62 to
the tlles 48 whlch sllp over the sald strlp. When the chalns BO
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llnked to the tubes 5~, drlve the tlles, drlll-holes 62 and 72
are always wholly or partlally alIgned, so ~hat the vacuum can be
delIvered; thls Is because the dlstance between holes 72 Is less
than thelr length whlle, at the same tlme, ~hey are the same size
as the holes 62 In the tlles. From tubes 58, the vacuum flows to
the mats 64; to prevent lealcs between the tlles, gaskets 74 are
provlded. Slmllarly, to ~nsure the seal between strlp 70 and the
tubes 58, rubber strlps 76 are provlded to complete the hermetlc
seal of the Inslde face of the conveyor's worklng surface.
Ano~her preferred deslgn replaces the drlll-holes 72
for a contlnuous openlng of the length correspondlng to the area
of applIcatlon of ths vacuwm, so that the alr movement In the
holes 62 In thls area Is never Impeded. The upper face ~ormed by
the mats 64 Is the support for the materlal to be cut; If It Is
not suffIclently Impermeable, throw~away plastlc can be used to
close thls surface, and the materlal, or the plastlc and ma~erlal
Is held In place under atmospherlc pressure. In the sectlons 60,
there are drlll holes 78 for securlng the coverlng plastlc by
means of the vacuum, thus preventlng these sectlons 60 from
enterlng the connectlons.
Another deslgn for the tlle ends shown In Flgure 7
would be to replace the sectlons ~0 wlth blocks of flexlble mate-
rlal 120 whlch Is also ImpermeablP, e.g. some type of plastlcfoam, whlch would be at the same helght as the mats 64, but
sllghtly wlder; the compresslon of thls excess over the tlle Is
what would prevent slde leaks; In the prevlous verslon, thls was
the functlon of the gasket 74 on the slde of sectlon 60. Depend-
Ing on the length of zones 38, 40 and 42 In Figure 3, the length
; Is fIxed of the drllled sectlon of tube 66 or, In other words,
the length over whlch the vacuum Is applled to the tlles. Flgure
8 shows a general layout of pressures, descrIbed qualltatIvely by
way of contlnuatlon.
~ The pump 68 generates a P0 vacuum, part of whlch Is
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iost In the ducting to the Input to tube 66. If a pressure of P1Is obtalned at the sald Input, there Is a further loss of load In
the transltlon to the tlles, ~n other words, at the mat, pressure
P2 wlll be greater than P1. As the se~urlng of the materlal 12
Is based on the dlfference between pressures Pa-P2, P2 needs to
be as low as posslble, thus requlrlng the smallest posslble loss
between the pump outpUt and the ma~ or, in other words, P2 should
be slmllar to P0, whlch Is the lowest pressure In the entlre clr-
cult.
The sald dlfference of pressure should be at a maxlmum
In the cuttlng zone 40, and, at zone 38, It shouid be enough to
carry the fabrlc from the spreadlng table.
At sectlons A and B, where the loop beglns to curve,
there Is an openlng to the atmosphere, so ~hat pressure P2 should
Increase progresslvely through the mat, untll reachlng atmo~
spherlc pressure Pa.
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The vacuum applIcatlon must be Introduced as far as
posslble Into zone 38; however, If ~n thls zone the pressure Is
P3, the loss of load Pa-P3 needed at openlng ~ wlll be obtalned
wlth hlgh flows, so that the pump's level of Impulslon wlll not
be sufflclent. Thus, the suctlon zone tends to be concentrated
; 25 and to be kept away from the open end sectlons, so as to obtaln a
good Pa-P~ dlfference. Thls gentle drop, because of the length
of mat reachedj ensures ~hat the materlal wlll be suffIclently
secured over an area whlch wlll allow It to be moved.
In the A sectlon on the dlscharge end, the problem Is
not so great; all tha~ ts requlred Is to take the precautlon
descrlbed above In the method for operatlon of collectlon from
zone 42, flrst, of panels whlch are neares~ to Section A and,
when the cuttlng brldge Is at the end of the cutttng zone 40, to
collect the panels whtch are tnslde ths collectlon zone.
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