Note: Descriptions are shown in the official language in which they were submitted.
tl ~
DESCRIYTION
This invention relates to a device for inaividually
separating flat objects, especial~y postal correspondence and
the like~ and spacing them at constant distances apa~t.
In man~ cases involving loose p~cks or heaps of flat
objects, ~hich are either st rest or arriving in a corltinuous
~r interrupted stream, it is required co form them into
regular stream of individual objects which are spaced at
constant distances apart.
A particular case of this kind is the handling,
distribut;on and automatic sorting of postal correspondcnce.
In this and other cases, the objects to be handled c&n
be of very variable dimensions and consistency (thicknas~),
and there can be considerable diflerences in the mass of the
objects, for instance of the order of 1 to 10. ~n exa~ple
is the comparison between a letter or postcard and an envelope
containing documents.
The problem is therefore to extract or ~rlthdraw one piece
at a time from a loose pack or heap of such ob~ct5~ i.n order
to make them avail3ble inclividuolly, and to then feed the
indiviaual objects into a conveyinæ line constitu-tea for
example by t~o opposing belts, 50 that the objects become
spaced at constant distances apart.
The conventlonal methods f()r carrying out these oper-
ations are generally based on the use of slotted permeablebel's or perforated drums which with the aid of vacuum created
b'r a suita7c~1e pump draw one object at a t me from a stationar~
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pac~ to cOuse it to adhere to the moving belt or drum, which
then releases the object withdrawn from the pôck and ins~r-ts
it into the conveying line.
The known devices are also fitted with 3pproprista
auxiliary equipm.ent~ for example for preventinO a numb0r of
objects being withdrawn or extracted at a time, this equipment
making the operOtion of said devices e~tremely complicated~
In general, these conventional systems always provide
for withdrawing the individuOl objects while stationary, to
the~ raise them inst~ntaneously to the speed of the conveying
line.
As the available times are small, even though the spseds
concerncd are not very high, the acceler~tion which the objacts
undergo on being withdra~m is very large, and because~ as
stated, the mass of the objects can difPer considerably, the
extrsction obtained, which is bafied on a constant accelerating
force, is strongly influenced by the physical characteristics
of the objects handled.
The object of the prescnt i.nvent:ion is ~hcr~fore to
provido a constructionally si.mple ~nd operationOlly raliable
device for i.ndividually separating fla-t; objects arld spOcing
them at constant distances apart, which carries out the
individual separation without the need for using sucti.on
means, in which the effect of the mass difference between the
objects is minimisea, and which is a].so able to operate on a
stream of arriving objects in additi.on to stationary packs or
heaps~ These objects are attained ~ccor-Iing to the inventio~
3~
by a de~ice characteri6ed by compri~ing two endless
motorised bands with their oppo5inO branches for~ing an
acute angle between them and resilientJy kept ~n r~lutual
contact at a verte~ zone of said angle to form a first
pinch point, means for feeding a plurality of fiat objects
to be handled into the V space deIined by said opposing
branches of the two bands, and, at a predetermined di~tance
downstream of the contact zone of the opposing branches of
the two bands, a con~eyor constituted by a pair of motorised
belts the opposing branches of which move in the same
direction snd at the same speed and are kept yieldably
adherinO to each other to form a second pinch point, one of
said two bands being of a material of high coefficient of
friction and being driven in such a manner that that branch
thereof which opposes the branch ot` the second band moves
in the same direction as, but at a smaller speed than, the
opposing branche~ of the conveyor belts, whereas the other
of the two bands is of a material having a lo-~ler coefficient
of friction than the first and is dri~en in such a mannor
20 that that branch thcreof wh:ich OppO6CS the br3nch of tho
first band moves in the opposite direction to, and at a
smaller absolute speed than this ]atter.
~ he means for feeding a plurality of objects to be
handled into the V space formed by the opposing branches of
the two bands can be constitut d by 3 band conveyor which
con~eys a stream of objects from any other machine upstream
of the device, or which with~ra~ts the obJect~ from 3 pac~.
The dist3nce between the two pinch or gripping polnts
formed by the two bands and by the conveyor belts is chosen
at a value le.ss than the mini~um length of the flat objects
to be handled.
The band of material having the lower coeEficient of
friction is suitably mounted on a swivel-mountedsupport onwhich
there act resilient means which are adjustable so as to
create in the contact zone between the opposing branches of
the two bands a pressure ~hich is substantially constant
independently of the thickness of the object ~ihich is passing
between said two branches at any given time.
: One embodiment of the device according to the invention
; is descri'oea hereinafter in greater detail with reference to
the accompanying drawings~ in which:
Figure l is a diagramMatic plan vie~r of the device on
the line I-I of Figure 3,
Figure 2 is a hori~ontal section on the 1.ine II-II of
Figure 3~
Figure 3 i.9 an elevation Or thc cl~vioe on the li.ne
III-III of Figure l~ and
Figure 4 is a diagram whicil schematically illustrates
the operation of the device.
The device described hereinafter is designea to individ-
uall.y separate and space-apart postal correspondence such ~s
letters of various formats and consistency, postcards etc.
In the C3Se considered, this postal correspondence is
fcd i.n the form of an un~o~nd pack of individual objects
~3l&3~
which are disposed ~erticslly1 iOe~ not resting on a surEace
by means of their wide face~ However, nothing prsvents tne
objects from bein~ fed while lying on a surface or on a band
conYeyor, and the spacial arrange~ent of the components of
the- device io not limited to the arran~ement ~hich is
illustrated b,'l way of example onl~.
Figures 1 to 3 show a hori~ontal support p;ate 1 with a
: horizontal restin~ table 10 for a pack 11 of flat objects
disposed ~erticall~ which is thrust by a pusher 12 in the
direction of the arrow 13. The table 10 is bounded on one
side by a verticaI fixed guide 14.
The end part of the resting table 10 passes a short
distance sbove the upper hori~ontal branch of a conveyor
bsnd 15 which moves in the direction of the arrow 16 and
I5 is guided over two deviation rollers 17, 1~. A second
verticsl collveyor band 19 guided over rollers 20, 21 and 22
has a branch in front of the resting table 10 which passes
at a distance above ths upper branch of the band 15~ this
branch of the band 19 moving in the ~,ame di.r~ction (arrow
16) and st the s~me specd as tho upper br~nch of the band
15.
The pack 11 of flat objects which is pushed forwsrd by
the pusher 12 on to the table 10 then p~sses on to the upper
branch of the belt 15 ~ultil it encounters ths facing vertical.
branch of the belt 19, so that some of the initi.al objects
of the pack 11 are thrust for~rard b~ the two bands 1~, 19
in the di.rection of the arrol~ 16, iOe. i.n practice
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per~endicular to the feed direction (~rrot~ 13) of the pack
11 on the table 10. That end of the vertical guide 1~ facing
the ~rertical band 19 is suitably bent in the direction of the
arrow 16 (see Figure 1) to create in front of the b~nd 19 a
passage for a certain number of ohjects~ It should be
n~ted that a sensor 23, ~or example of the known capaciti~-e
type9 detects the presence of objects on the table I0 and
controls the pusher 12. For simplicity, the operating and
control means for the pusher 12 are not shown~ this latter
being mobile Iinearly along the guide 24 parallel to the
table 10.
The passage for said certain number of objects in front
of the vertical band 19 terminates in the feed directio~. of
said objects (arrow 16) in the forra of a V space created by
the opposing branches 25 and 26 of two endless vertical
banas 27 sna 28, the opposing branches 25 and 26 forming an
acute angle between each other.
The band 27, which is constituted of a rnsterial havin~
a high coefficient of friction, for example a special rubber,
is supported and guidea on rollers 29~ 30~ 31~ Or whi.oh the
roll~r 30 is ~ tensionln~ ro].l~r. Xt~ branc}l 25 moves in
the same direction as the feed direction of the objects
(~rrow 16).
The band 28 is supported and guided on rollers 32, 33,
34 ana 35 of which the roller 34 is a ten6ioning roller~ and
it is constituted by a norm3l rubberised band having a
coefficiei1t of friction substzntially less than that of thP
band 27 ~for example the ratj.o of thc coefficierlts of friction
of the two bands is 1:2~. The branch 26 of th~ band ~8 also
moves in the opposite direction to the feed direction of the
objects (in the opposite direction to the arrow 16).
The support and guide rollers 32_35 for the band 28
are carried by 3 support 36 which is mountea to s~rivel about
the axis of the roller 33 on the plate 1~ and is subjected to
the action of a tension spring 37 which rotates the support
36 in such a direction as to move the front end (with
reference to the feed directioll of the objects as indicated
by arrow 16~ of the branch 26 of the band 28 into contact
with the brsnch 25 of the band 27 with a detcrmined pressure,
as is clearly visible in Figure 1. This contact zone
between the branches 25, 26 of the bands 27, 28 forms a first,
pinch point, indicated by 38.
It is important to note that the opposin~ branches 25
and 26 of the bands 2'" 28 form a contai.ned open scut.e angle,
and are properly kept in mutual contact at the vertex zone
of t'nis angle, i.e~ at said first pinch point 38. For this
purpose, the position of the tensioning roller 30 for the
band 27 relative to thc deviat:i.on .rol:Lcr 35 of the band 2P,
is irnportant. ~9 clearly vi~:ible i.n Fi.nure 1, by deviati.ng
the branch 25 of thc band 27 from the straight line jolni.ng
the deviation rollers 29 and 31~ the tensioning roller 30
pushes it against the branch 26 of the band 28, which is kept,
taut between its devi.ation rolle~s 32 and 35. This arrange-
ment ensl~es the passage of onl~ one of the objects throucgh
the ~inch point 389 independently of the thrust e:~erted b~
the ~,ubsequent objects which 2~20T~e towards s~id piIlch point
~nto the V space between the two branchas 25, 26 of the bands
27 and 28.
The force of the spri.ng 37 can be adjusted by means of
an adjustable tie rod 39~ adjustable stop 40 limits the
rotation of the support ~6 under the action of the spring 37.
r~he force o~ the spring ~7 and its positionir.Lg relative
to the pivot of rotation of thc support 36 are determined in
such 3 manner as to obtain a substantially constant p~essure
at the pinch point 38, independently of the opening of the
bands 27, 28 determined by the passage of an object through
the pinch point 38 and by the variable thickness of the
~assing object (the difference irL thickness between the
objects can be considerable, even of the order of 1 tG 10).
A vertical belt conveyor constituted by a beit 41 guided
over pulleys 42, L~3 and 44 and a belt 45 guided over pull.eys
46, 47, l~8, 49 and 50 is proviaed at a certain distance down~
etrea~n of the zone of contact of the opposing branches 25, 26
of the two bands 27, 28. Ovcr a certai.n port.ion7 the t~o
belts l~l and 1~5 rlm p.~r~llcl to eiJCh othor in thc feed
direction of the objects (arrow 16) and at th0 same speed,
and ove~ this portion the belts are kept yieldably in mutual
contact by virtue of the arrangement of th~ pul].eys 46, 47
and 48 relative to the pulle~fs 4~ 4 as shown in Fi.gure 1~
the pulley 47 bein~ a tensioning pulley. The beginnirlg of
this portion forL~Is a second pi.nch pOi21t ind~~cated bv 51.
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It shou1d be noked that the distance betweer. the pinch
point 38 formed by the two bands 27, 28 and the pinch point
51 formed by the ~wo belts 41, 45 iS less than the minimum
len~th of the flat objects (postal correspondence) to be
handled.
The bands and various belts of the device are driven
from a single motor 52 mounted below the support plate l
(see Ficures 2 and 3). ~wo pulleys 53 7 54 3re mounted on
the drive shaft. The pulley 53 drives, by way of a belt
tr3nsmission 55, the pulley 56 which is mounted on the shaft
of tne drive roller 17 of the b~nd 15, said belt 55 being
guided over two deviation pu]leys 57 arld 580 ~he pulley 54
drives the band 19, the p~ir of bands 27, 28 and the belts
411 45 of the downstream conveyor by way of a sing~le belt
transmission 60. The belt 60 takes the follo~ling path:
from the pulley 54 it passes over a deviation pulley 61,
over a drive pulley 62 ~ounted on the shaft 63 carrying the
drive roller 33 for the belt 28 (s3id shaft ~lso constitutin~
the axis of rotation for the suppo~t 36), then over a drive
pulley 64 mounted on the sh~ft 65 carr~ing tho drivo pulley
49 for the bclt L~5, then over ~ devistion pu]loy 6G, then
over a drive pulley 67 mounted on the shaft 68 carrying th~
drive pulley 44 for the belt L~l, then over a deviation pulley
69 and finally over a drive pullcy 70 ~o~ted on the shaft 7]
carrying the drive rollers 22 and 31 for the band l9 ~nd band
27 respectively, to then return to the pulley 54 (see
Figure 2 in particular).
3~;
The transmission ratios axe chosen such that when the
band 27 moves in the feed direction 16 of t~e objects! it
has a linear speed greater than the linear speed of the band
28 which mo~es in the opposite direction, and such that t.he
belts 41, 45 of the downstream conveyor ha~e a linear speed
greater than that of the belt 27.
The operation of the described device is as fGllows.
The pack 11 of flat objects thrust by the pusher 12 on
the table 10 in the direction 13 arrives on the horizontal
ban~ 15 and abuts against the facing branch of the vertical
band 19. The two bands 15 and 19 urge the initial ob,jects
of the pack 11 in the direction 16, and the bent part of the
vertical guide 14 allows some of them to pass into the
V-constrict~3d space of the opposing branches 25, 26 of the
I5 bands 27, 28. These objects thus tend to accv.mulate in
said V space.
Because of its high coefficient of friction, the band
27 tends to drag the objects forward in the direction 1.6,
while the other band 28 which rotates in the opposite
di.rection at a lower s~)ced, and wh.ich h~s ~ coef~icient O:r
friction which is sub~st~nt.i~lly less th.JIl the Eirst, tends
to halt the objects which slide against it.
~ n individual object which becomes gripped between the
two bandfi 27, 28 at the first pinch point.38 is urged forward
on one of its faces by the band 27, whereas it is urged
backward on its other f~ce by the band 28. The pressure
acting on the two faces of the object i.s obviously the same,
where~s the coefficient of friction of the band 27 i8
substantially greater (with ~ ratio for ~mple cf ~:1! than
that of the band 28, ana thus the .orward thrust action of the
band 27 prevails with the result that the object is ~oved
forwara at the speed of the band 27 towards the do~stream
conveyor.
If two objects simultaneously reach the pinch point 38,
th~t facing the band 27 is caused to molfe for~ard in the
~irection 16 thereby, whe~eas the other f~cing the band 28 is
halted ana then caused to move backward, because the branch 26
of the band 28 ~oves in the opposite direction to the feed
direction. On the other hand, the bands 15 and 19 and the
other objects conveyed forward thereby continue to thrust
this latter object forwsrd, so that in practice it stops
slightly upstream of the pinch point 38, where the b3nd 28 is
no longer ab:Le to move it backward because of lacic of ressure.
This ~econd object therefore remains ~Jai-ting until the first
object in complete].y passing beyond the r,inch po~ition 3
uncovers the band 27, which by then acting on the second
object moves it forw~rd at th.i.s point.
If tho bc~lt convcyor ~ l5 w~ro to InOVe Porward at the
same speed as the band 27, the objects wou].d simply file ~ast
one at a time without any gaps betweon them. A contlnuous
stream of objects wou].d therefore be cr~ated. It should be
noted that be~inning with their forward movement on the table
10, the objectls can be acceler3ted in a number of stages~
firstly by the bands 15 and 19 an~ -then b~ the band 27, with
the result that the effect of thelr mas6, which can be very
different, is minimised.
However, to obtain a g3p between one object and the
ne~t, the belts 41, 45 of the downstream conveyor ~re made
to move at a speed greater than the band 271 ana in ~ddition
the conveyor, which h~s a rel3tively long portion of the two
belts pressed ~gsinst esch other, is cIesigned to be able to
apply a force to the object which is greater than that
exerted by the bsnd 27. ~lhen an object reaches the secona
pinch point 51 by being thrust by th~ band 27, it matches its
speed to that of the belts 41 and 45 because of the greater
power of the belt convey~r, so that when the object ~thich
succeeds it at its rear ena is moved forward by the band 27,
it advancea at a lower speed (that of the bancl. 27) between ths
point 38 and the ~oint 51. In thls t~anner, a g~p is created
between the two objects which can be predetermine-l b~
zdjustin~ the difference in speed between the band c7 ard the
downctream conveyor, and the distance between the pinch points
38 and 51.
In order to obtain an eq-lal grap bctwecn thC v~riouFI
objects wh:i.ch is lndep~ndont o~ the lellæth o~ the objects, the
distance between the pi.nch points 38 ancl 51 has on].y to be l.ess
than the minimum length of the objects to be h3ndled,
The thickness differences which can e~cl~t between the
objects in a same pack and which -as stated - Call reach
considerab~e values, such as 1 to 101 are ~bsorbed in that the
band 28 is mounted on the st~ivel~mounted 5llpport 35 which can
1!~
move away fro~ the band 27. The spring 37 aeti~g on the
support 36 ~reates the forc~ necessary f~r ~resslng the band
28 against the objeets and against the band 27 with -the
required pressure. The size of the spring 37 and its
position relative to ths s~ivel axis of the support 3~ are
sueh as to obtain T~ithin practical limits a pressure whieh
is substantially constant at the pinch point 387 independently
of the tnickness of the object which is passing through it at
any tlme
The operation of the device for spacing objeets at
eonstant distanees apart is shown schematieally in the
diagram of Figure 4, in whieh the abscissaeindicate the
spaces and the ordinates the times. ~he two lines 3c~ and 51
irldicate the two pinch points for the objects between the
bands 27, 28 and the belts 41, 45.
~ t time a -tl!ere are three objects A, B and C of different
length with their front edges (in the direction of movement)
at rest at the first pinch point 38. At time b, the object
A is ad~-anci~g under the thrust of the band 27 of high
coeffieient of friction, while the other two objeets B and
C remain at rest.
At t:ime e, tho front eclge of the object A roaehes the
second pinGh point 51, while the object is still gripped by
the bands 27 and 28. At time c7 it ean be seen that because
of the greater 3peed and ~ripping force of the belts 41 and
45, the objeGt ~ is made to advance rapidl~- ~lthough its rear
end is stil:L gripped by the kands 27 anrl 28, so tnat the
d;~6
obJects B ~nd C still remain at rest. At time e the objec-t
A is free from the bands 27 and 28, DO that the first of these
now causes the next object ~ to advance. At time f it can be
seen that the gap between the objects A and B has increased
because of the greater forward speed of -the first, the rear
end of which has l.eft the secorld pinch point ~1, whereas the
followin~ object has not yet reached this point, so that the
gap b~tween the two objects A and B incre~ses further.
Finally9 at time g, the object ~ has reached and passed be~cnd
the second pinch point 51, and now moves forward at the same
speed as the object .~, while because of the fact that its
re~r end has been released from the grip at the irst pinch
point 38, the third object C can now move forward under the
thrust of the band 27.
The aforegoing description clsrifies the operation of
the device according to the invention, which is based on the
conee~t of utilising the friction whieh develops between the
surface of the flat object and a rubberised band of high
coefficieilt of friction.
It should be noted that i.nste~d of using a statiOn3ry
table on which a 10060 pack of obj~cts i.s moved forward by
a pusher, a mobile table could be used, or even a conveyor
belt l~rhich feeds a continuous stream of flat objects. In
this ease, the objects could be fed in packs or heaps, or
even individually~ for e~ample directly in the feed direction
16 on to that branch of the bana lC3 which carrics the object,
into the V space between the two bancls 27 and 28. If the
16
device feeds in this latter manner, it can be advantageous
to dispose the band 19, the pair of bands 27, 28 and the
downstresm conveyor comprising the belts 41 and 45 horizon-
tally instead of vertically. In this case, the devioe
again operstes in the ssme manner a,s heretofore described.
