U.S. patent number 3,552,736 [Application Number 04/776,351] was granted by the patent office on 1971-01-05 for method and apparatus for folding disposable diapers.
This patent grant is currently assigned to Kimberly-Clark Corporation. Invention is credited to Richard H. Frick, Terry M. Weber.
United States Patent |
3,552,736 |
Frick , et al. |
January 5, 1971 |
METHOD AND APPARATUS FOR FOLDING DISPOSABLE DIAPERS
Abstract
A method and apparatus for folding precut sheet material, such
as disposable diaper blanks, as they move in spaced-apart relation
along a conveyor path. The folder includes apparatus for
preliminarily folding the blank along a medially located transverse
fold line and over a triangular-shaped folding board and further
apparatus for diagonally folding over the legs of the folding board
the material initially located along the transverse fold line on
either side of the center thereof and for tucking this material
between the upper and lower portions of the preliminarily folded
blank while also reversely interfolding therebetween the material
initially located along the transverse fold line most distant from
the center thereof. The folding apparatus also includes means for
picking the folded blank off the folding board and for stripping it
from the picker. A preferred form of the apparatus also includes
automatic glue guns for applying discrete spots of adhesive at
specific points on the underside of the blank prior to the folding
operation.
Inventors: |
Frick; Richard H. (Neenah,
WI), Weber; Terry M. (East Flat Rock, NC) |
Assignee: |
Kimberly-Clark Corporation
(Neenah, WI)
|
Family
ID: |
25107147 |
Appl.
No.: |
04/776,351 |
Filed: |
November 18, 1968 |
Current U.S.
Class: |
493/331; 223/37;
493/406 |
Current CPC
Class: |
D06F
89/00 (20130101) |
Current International
Class: |
D06F
89/00 (20060101); B65h 045/00 () |
Field of
Search: |
;270/61 ;223/37 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Schnall; Jerome
Assistant Examiner: Williams; Paul V.
Claims
We claim:
1. The method of folding disposable diaper blanks into
substantially infant-conforming configuration comprising the steps
of:
conveying the diaper blanks in spaced-apart, end-to-end relation
along a predetermined flow path;
bringing a folding board into registry with the rear half of each
diaper blank as it moves along said flow path;
intercepting the leading portion of each diaper from below with a
rearwardly inclined folding bar moving at a speed slower than the
diaper to lift said leading portion and preliminarily folding it
over the folding board along a medially located transverse fold
line; and
engaging the portions of the diaper located along said transverse
fold line on each side of the center thereof with a side tucking
element to interfold said portions between the upper and lower
surfaces of the preliminary folded diaper while reversely
interfolding between said portions the part of the diaper located
along said transverse fold line most distant from the center
thereof.
2. The method defined in claim 1 including the preliminary step of
applying controlled quantities of adhesive to the underside of the
diaper blank at such locations as to be subsequently enclosed
between interfolded layers of the diaper.
3. The method defined in claim 1 including the intermediate step of
withdrawing the folding bar from the preliminarily folded diaper
blank by accelerating the bar down and away from the folding board
before the folding bar is overtaken by the folding board.
4. The method defined in claim 1 including the intermediate step of
frictionally engaging the upper and lower surfaces of the
preliminarily folded diaper blank to keep the blank substantially
tautly stretched over the folding board during the side tucking and
interfolding operation.
5. The method defined in claim 1 including the step of actuating
said side tucking elements with an elongated cam track which is
effective to swing said elements into engagement with said portions
of the diaper to be interfolded.
6. The method defined in claim 5 wherein each of said side tucking
elements includes a cam follower and said cam followers are biased
into engagement with said elongated cam track.
7. The method defined in claim 1 including the further step of
picking each of the folded diapers from the folding boards with a
picking element traveling at a speed greater than that of the
folding board.
8. The method defined in claim 7 including the additional step of
stripping the folded diapers from the picking element with a
stripping element traveling at a speed greater than that of the
picking element.
9. The method defined in claim 2 including the further step of
compressing the folded diapers in order to crease the fold lines
and insure good contact of the adhesive with the interfolded layers
of the diaper.
10. The method defined in claim 1 wherein a plurality of the
folding boards are moved along a closed loop disposed in part
parallel to and in close proximity to said flow path.
11. The method defined in claim 1 wherein a plurality of said
folding bars are moved along a closed loop disposed in part to
intersect said flow path from below at an acute angle.
12. The method defined in claim 7 wherein a plurality of said
picking elements are moved along a closed loop disposed in part to
intersect and then move along said flow path.
13. The method defined in claim 8 wherein a plurality of said
stripping elements are moved along a closed loop disposed in part
parallel to and in close proximity to said flow path.
14. The method defined in claim 7 wherein said picking element is
advanced through a slot located in the lower surface of said
folding board along the longitudinal center line thereof.
15. The method defined in claim 8 wherein said stripping element is
advanced past said picking element with portions of said stripping
element straddling said picking element and engaging the rear edge
of the folded diaper.
16. Apparatus for folding precut diaper blanks traveling in
spaced-apart relation and timed sequence along a predetermined flow
path comprising, in combination:
a folding board mounted for continuous movement along a first loop
disposed in part parallel to and in close proximity above said flow
path;
means for moving said folding board in timed sequence with said
blanks so that the under side of said folding board periodically
engages the trailing portion of respective ones of said blanks and
moves in unison therewith;
a rearwardly inclined folding bar mounted for continuous movement
along a second loop disposed in part to intersect said flow path
from below at an acute angle; and
means for moving said folding bar in timed sequence with said
blanks but at a lower rate of speed so that said folding bar
periodically engages and progressively lifts and folds the leading
portion of respective ones of said blanks over the upper surface of
said folding board along a medially located transverse fold line as
said folding bar moves from below and ahead to above and behind the
forward portion of said folding board.
17. Folding apparatus as defined in claim 16 including means for
forwardly swinging said folding bar down and away from said folding
board and out of engagement with said folded blank.
18. Folding apparatus as defined in claim 17 including guide means
located in close proximity to said flow path downstream of said
intersection for engaging and holding said folded blank over said
folding board as said folding bar is swung away.
19. Folding apparatus as defined in claim 16 wherein said folding
board is of generally triangular shape with the apex thereof
forming the leading edge and said folding bar includes an element
extending substantially transverse to said flow path for folding
said blank over said apex.
20. Folding apparatus as defined in claim 16 wherein said folding
board includes a pair of spaced-apart forming surfaces of generally
triangular shape with aligned forwardly projecting apices and
rearwardly diverging legs and an intermediate forming element
between said surfaces having interiorly facing edge portions
extending outwardly substantially at right angles to said legs and
means for tucking the preliminarily folded edge of said blank
outboard of said apices so as to interfold the material thereof
over said legs and edges and between said forming surfaces.
21. Folding apparatus as defined in claim 20 wherein said tucking
means includes a element on each side of said folding board
swingable between said forming surfaces and around said forming
edge.
22. Folding apparatus as defined in claim 21 wherein each of said
swingable elements carries an operating arm fitted with a cam
follower and said cam followers are biased into engagement with an
elongated cam track shaped to first progressively swing said
elements toward each other from opposite sides of the folding board
and then swing said elements away from each other.
23. Folding apparatus as defined in claim 20 wherein said forming
surfaces are substantially horizontally disposed as said blank is
interfolded, the lower one of said forming surfaces being slotted
along its longitudinal center line to receive a picking pin and
means are provided for moving said picking pin through said slot to
remove said folded diaper from said folding board.
24. Folding apparatus as defined in claim 23 including a plurality
of forming boards and a plurality of picking pins mounted for
movement in timed sequence with said folding boards but at a faster
speed, in order to pick said diapers from said folding boards as
said picking pins advance successively through said slots.
25. Folding apparatus as defined in claim 24 including a plurality
of stripping elements mounted for movement along a closed loop in
part parallel to and in close proximity with said picking elements
but at a faster speed in order to strip said diapers from said
picking elements.
26. Apparatus for folding precut diaper blanks comprising, in
combination:
a forming board including elements defining a transverse fold line
about which said blank is preliminarily folded;
said forming board also including elements defining a pair of
spaced-apart and generally parallel forming edges having
substantially triangular configurations with outwardly projecting
apices;
said forming board including further elements defining intermediate
forming edges lying between said spaced triangular forming edges
and extending substantially perpendicularly inwardly therefrom;
and
tucking means engageable with said blank at a pair of points spaced
along said transverse fold line on opposite sides of said apices
and between said intermediate forming edges for diagonally
interfolding the side portions of the diaper between said spaced
triangular forming edges and reversely interfolding the marginal
diaper material over said intermediate forming edges.
27. Apparatus as defined in claim 26 wherein said forming board is
mounted for movement along a flow path on which said diaper blanks
are preliminarily deposited in spaced-apart relation and in timed
sequence to register with the trailing portion thereof and
including a moving folding bar mounted for movement along a path
which intersects said flow path and in timed sequence to intercept
the leading edge of said diaper blanks for preliminarily folding
said diaper over said folding board.
28. Apparatus as defined in claim 27 wherein said tucking means
includes a element on each side of said folding board swingable
between said forming surfaces and around said forming edge.
29. Apparatus as defined in claim 28 wherein each of said swingable
elements carries an operating arm fitted with a cam follower and
said cam followers are biased into engagement with an elongated cam
track shaped to first progressively swing said elements toward each
other from opposite sides of the folding board and then swing said
elements away from each other.
Description
This invention relates primarily to sheet folding methods and
apparatus and more particularly concerns automated methods and
apparatus for folding disposable diapers into substantially
child-conforming shape.
In recent years new materials and advanced manufacturing techniques
have made possible the mass production of disposable diapers which
can effectively compete with conventional laundered diapers. This
is particularly true of those disposable diapers which include a
fluid-impervious backing sheet that takes the place of the separate
plastic or rubber panties normally required for use with
conventional launderable diapers. However, the incorporation of
such a fluid-impervious exterior for disposable diapers makes it
even more essential that the diaper be properly folded into a
body-conforming shape in order to enhance the holding capacity of
the diaper as well as avoid unnecessary contact of the impervious
cover with the infant's skin which might cause irritation.
A disposable prefolded diaper meeting the foregoing requirements is
disclosed in Hrubecky, U.S. Pat. No. 3,196,874. As disclosed there
such diapers are machine embossed or otherwise creased along
designated prefold lines to facilitate subsequent folding of the
diaper into substantially child-conforming and excrement entrapping
configuration. This does, of course, make it much easier to prefold
the diaper; but, nevertheless, even with skilled personnel the
number of diapers that can be folded is limited.
Accordingly, it is the primary aim of the present invention to
provide an automated method and apparatus for prefolding disposable
diapers on a high volume production basis.
It is a more specific object to provide a method and apparatus for
prefolding disposable diapers in the desired body-conforming shape
as they move continuously along a flow path.
A more detailed object is to provide a method and apparatus for
preliminarily folding a disposable diaper blank along a medially
located transverse line and then to subsequently tuck the marginal
portions of the diaper located along the preliminary fold line
between the upper and lower surface of the diaper while also
reversely interfolding therebetween the material initially located
along the transverse fold line most distant from the center
thereof.
Another object of the invention is to provide a method and
apparatus for applying discrete spots of adhesive to specific spots
on the diaper blank prior to folding, which adhesive spots are
effective in retaining the diaper in its desired prefolded
configuration.
Other objects and advantages of the invention will become more
readily apparent upon reading the following detailed description
and upon reference to the drawings in which:
FIGS. 1a and 1b are, respectively, side elevations of the blank
receiving and discharge ends of the folding apparatus of the
present invention;
FIG. 2 is an enlarged fragmentary section taken along line 2-2 in
FIG. 1;
FIG. 3 is an enlarged fragmentary section and FIG. 3a is a
fragmentary section, respectively, taken along lines 3-3 and 3a-3a
in FIG. 2;
FIG. 4 is a plan view of a precut diaper blank before folding;
FIG. 5 is an enlarged fragmentary perspective view of the apparatus
for initially folding the blank across a transverse fold line;
FIG. 7 is a side elevation of the apparatus shown in FIG. 5;
FIGS. 7 and 8, respectively, are further enlarged fragmentary
sections taken along lines 7-7 and 8-8 in FIG. 6;
FIG. 9 is an enlarged fragmentary plan view of one of the folding
boards and side tucking assemblies;
FIGS. 10 and 11, respectively, are sections taken along lines 10-10
and 11-11 in FIG. 9;
FIG. 12 is a fragmentary plan view of the side tucking portion of
the folding apparatus shown in FIG. 1;
FIG. 13 is an enlarged fragmentary section taken along line 13-13
in FIG. 12;
FIG. 14 is a perspective view of a previously folded blank,
partially unfolded to illustrate the interfolded portions;
FIGS. 15a and 15b, respectively, are enlarged fragmentary side
elevations of portions of the apparatus shown in FIGS. 1a and
1b;
FIGS. 16 and 17, respectively, are fragmentary sections taken along
lines 16-16 in FIG. 15a and 17-17 in FIG. 15b;
FIG. 18 is an enlarged fragmentary side elevation of a further
portion of the apparatus shown in FIG. 1b;
FIG. 19 is an enlarged fragmentary section taken along line 19 -19
in FIG. 18;
FIG. 20 is an enlarged fragmentary side elevation of the final
portion of the apparatus shown in FIG. 1b; and,
FIG. 21 is an enlarged fragmentary section taken along line 21-21
in FIG. 20.
Turning now to the drawings, FIGS. 1a and 1b, when taken together,
comprise a side elevation of the folding apparatus 25 of the
present invention. This folding apparatus has particular utility in
automatically folding precut diaper blanks 26 (see FIG. 4) into
diapers 27 (see FIG. 14) which have a substantially
child-conforming shape as disclosed in Hrubecky, U.S. Pat. No.
3,196,874 assigned to the instant assignee. However, it should be
understood that certain aspects of the apparatus 25 also have
utility for folding other precut blanks of material in addition to
diapers.
In their preferred form, the diaper blanks 26 are of multilayer
construction such as disclosed in copending Endres application Ser.
No. 715,301, filed Mar. 22, 1968, now U.S. Pat. No. 3,520,303, to
which reference may be made for further details. Such diaper blanks
may be made on a disposable diaper forming apparatus such as
disclosed in copending Frick application Ser. No. 776,580, filed
Nov. 18, 1968 to which reference may also be made for further
details of the blank forming apparatus. Both of the foregoing
applications are also assigned to the instant assignee.
The particular construction of the diaper blanks and the apparatus
for making them, however, need not follow the teaching of the two
above-mentioned applications. Rather the blanks can be of other
constructions formed on other types of apparatus and, indeed, as
noted above need not be intended for diapers insofar as practicing
certain aspects of this invention as described below. Accordingly,
only the discharge portion of a blank forming apparatus 28 is
illustrated in FIG. 1a and it will be understood that it need not
be disposed inline with the folding apparatus 25 which is the
subject of the present application.
Similarily, although the preferred diapers 27 are provided with a
pair of adhesively faced tapes 29 for convenience in holding the
diapers on a child, such tapes are not important to the present
invention and may be replaced with conventional diaper pins if
desired. Thus, while a tape applying machine 30 has been
illustrated generally in FIG. 1a as interposed between the blank
forming apparatus 28 and the folding apparatus 25 of the present
invention, the tape machine can also be omitted. In any event it is
of conventional construction and need not be discussed in detail
here.
Viewed in terms of its operation the folding apparatus 25 of the
present invention includes six operating sections, namely: a
receiving and speedup section 31; a glue applying section 32; an
initial folding section 33; a side tucking section 34; a pickoff
section 35; and a stripping and discharge section 36. Each of these
sections will be discussed in detail below; but, first a few
comments about the preferred prefolded shape of the diaper and on
the overall operation of the folding machine should be helpful in
understanding the detailed descriptions which follow. Also, it will
be appreciated that the apparatus shown in FIGS. 1a and 1b is
somewhat schematic in form and that the diaper blanks have been
omitted here to facilitate a clearer illustration of the various
machine components.
As previously mentioned the preferred form of the prefolded diaper
is of a substantially body-conforming and excrement entrapping
configuration as disclosed in the above-mentioned Hrubecky patent.
As illustrated here in FIG. 14, such a prefolded diaper 27 is
formed with front and rear triangularly shaped, body encircling
portions A and B joined by a depending excrement trapping pocket C
adapted to be disposed centrally in the crotch area and by
reversely interfolded leg engaging portions D, only one of which is
shown. This is the final product of the folding apparatus 25
disclosed here.
The initial diaper blank 26 is illustrated in FIG. 4 with a
preliminary fold line indicated by a solid line 26a extending
transversely across the diaper blank 26 through its center 26b.
Diagonally disposed fold lines 27a and 27b which intersect at the
center 26b to define the triangular legs of portions A and B are
shown in dash lines as are intersecting interfold lines 27c and 27d
which separate the pocket C from the leg engaging portions D on
each side of the longitudinal center line of the diaper blank
26.
Returning now to FIG. 1a and proceeding from the left, precut
diaper blanks 26 from the forming apparatus 28 pass in end-to-end
relation through the tape machine 30 on a conveyor 37 and are
received by a conveyor 38 at the speedup section 31 of the folding
apparatus 25. Both of the conveyors 37, 38 are preferably driven in
timed relation by a main drive motor 39 through a common drive
shaft 40. As shown in FIG. 1a, the drive shaft 40 drives a lay
shaft 41 which runs along the length of the folding machine 25 and
which is coupled to a series of gear transfer cases 43--47 through
appropriate chain or timing belt connections. The conveyor 38 is
driven from transfer case 44 and the conveyor 37 is driven at a
slightly slower speed by a similar lay shaft and gear transfer
arrangement, now shown.
As the diaper blanks begin to travel on the conveyor 38 they are
also intercepted by an overlying conveyor 48 driven from the shaft
40 through a gear case 49 at the same speed as the conveyor 38.
Thus as each diaper blank is engaged by conveyor 38 and 48 it is
propelled forward at a greater speed than the next trailing blank
on conveyor 37 resulting in a predetermined longitudinal spacing of
the blanks along the conveyor 38.
The diaper blanks are received on the conveyor 38 with their
outside, preferably a fluid-impervious layer, facing down. Prior to
entering the folding section 33 they pass over a pair of glue guns
50 in the glue-applying section 32. The glue guns are actuated in
timed relation to the movement of the diapers on the conveyor 38
such that two discrete spots of adhesive are applied to the
underside of the diaper blank at specific points prior to the
folding operation.
From the glue section 32 the diaper blanks pass into the initial
folding section 33 where each diaper blank is engaged by one of a
plurality of folding boards 51 mounted for movement about a
conveyor loop disposed in part parallel to the conveyor 38. The
timing of the folding boards 51 which are driven from the lay shaft
41 through gear case 45 is such that each folding board engages the
rear half of its respective diaper blank and then travels in unison
with the conveyor 38. The initial folding section 33 also includes
a plurality of folding bars 52 mounted for continuous movement
along a second loop disposed in part to intersect the common path
of the conveyor 38 and folding boards 51 from below at an acute
angle. The folding bars 52 are driven from the lay shaft 41 through
gear case 43 in timed sequence with the movement of the blanks on
conveyor 38 but at a lower rate of speed so that each folding bar
periodically engages and progressively lifts and folds the leading
portion of respective ones of the blanks over the upper surface of
the folding board as the folding bar moves from below and ahead to
above and behind the forward portion of the folding board. This
results in preliminarily folding the diaper blank over the folding
board 51 along transverse fold line 26a (see FIG. 4). The folding
bars 52 are then drawn out of engagement with their respective
diaper blanks as the blanks enter the side tucking section 34 of
the folding machine 25.
In the side tucking section 34 additional elements of the forming
board 51 are actuated (as will be described below) to interfold the
diaper blank along diagonal fold lines 27a--d (see FIG. 4) to form
the diaper into the body-conforming shape illustrated in FIG.
14.
Following the folding operation each diaper blank is removed from
its folding board 51 by one of a plurality of picker pins 54
mounted for continuous movement along a conveyor loop disposed in
part parallel to the lower path of the folding boards. The picker
pins are driven by the lay shaft 41 through gear case 46 in timed
relation with the folding boards 51 but at a faster speed such that
each picker pin moves along its upper path from behind one of the
folding boards to ahead of the folding board pushing the diaper
blank off the folding board before it makes its return loop.
Subsequently, the diaper blank is removed from the picker pin 54 by
a stripper element 55 driven along a continuous loop above the
picker pin loop by the lay shaft 41 through the gear case 47. The
stripper element 55 is driven in timed relation with, but at a
faster speed than, the picker pin 54 such that the diaper blank is
pushed off the picker pin and is discharged from the stripper
section 36 through a pair of compression rolls 56, 57 down a chute
58 and onto a take away conveyor 59 only a portion of which is
shown.
In operation a folding machine 25 of the type illustrated is
capable of folding 100 diapers per minute, or even more. The diaper
blanks may be of various sizes but one preferred size is 121/2
inches .times. 171/2 inches. Thus, if the diaper blanks are
disposed in end-to-end relation as they pass through a tape machine
30, the speed of the conveyor 37 would be 1,750 in/min. The speed
of the conveyors 38, 48 however are faster, preferably 2,000 in/min
in order to place the diaper blanks on 20-inch centers or, in other
words, spaced 2 1/2 inches apart. The folding boards 51 also are
spaced on 20-inch centers and travel at 2,000 in/min since they
register with and move in unison with the diaper blanks during the
folding and tucking operations.
The folding bars 52 are likewise disposed on 18-inch centers but
their movement is somewhat slower than the folding boards 51. The
folding bars for example may be timed to move at 1,800 in/min in
order to perform their initial folding operation. The picker pins
54 are spaced on 24-inch centers and since each pin carries a
folded diaper 27 off its folding board 51 the picker pins travel at
a speed of 2,400 in/min. Finally, to strip the diapers 27 from the
picker pins 54, the stripper elements 55 are spaced on 30-inch
centers and travel at a speed of 3,000 in/min in order to
accommodate 100 diapers per minute.
RECEIVING AND SPEED-UP SECTION
As illustrated in FIG. 2, the preferred embodiment of the conveyor
38 includes three laterally spaced belts 61, 62, 63 which move in
unison. The two edge belts 61, 63 are longer than the center belt
62 for reasons which will shortly appear. The edge belts travel
around support rolls 64--66, drive roll 67 and belt tensioning
rolls 68, 69 (see FIG. 1a). The drive roll 67 is driven by gear
case 44 through a suitable timing chain or belt. The center belt
travels around support rolls 64--66 and tensioning rolls 70, 71 and
is driven by the edge belts. Each of the rolls 64--71 is journaled
by bearings mounted on the frame of the folding machine 25.
The cooperating speedup conveyor 48 includes a pair of laterally
spaced belts 72, 73 which are trained over pulleys 74 and 75
mounted respectively on a drive shaft 76 and an idle shaft 77. The
bearings journaling the idle shaft are preferably adjustably
mounted on the machine frame to permit belt tension adjustment. The
drive shaft is also journaled in bearings mounted on the frame and
is driven from gear case 49 through a suitable timing belt and
pulley arrangement.
GLUE APPLYING SECTION
The glue guns 50 are mounted on the machine frame just downstream
of the speedup belts 72, 73 and are laterally spaced to squirt
through the space between the conveyor belts 61--63. The glue guns
are of the conventional pneumatic operated type and are mounted on
adjustable gimbals 80 secured to the machine frame (see FIG. 3a).
Control of the glue guns is through a photocell sensor 81, to be
described, which actuates a conventional solenoid valve (not shown)
in the pneumatic supply line to the guns. The amount of glue
applied is regulated by a conventional timing relay coupled in
series between the sensor and the glue guns. Preferably, the glue
guns are of the heated, hot glue-circulating type which are well
known in the art.
To prevent actuation of the glue guns 50 when there is no diaper
blank 26 above the guns, another photocell sensor 82 is provided
adjacent the glue guns and coupled in series with the sensor 81.
The sensor 82 also includes a light source and photocell (not
shown) which may both be located below the path of movement of the
diaper blanks 26 on the conveyor 38. A mirror 83 positioned above
the conveyor reflects light from the light source to the photocell
of the sensor 82 and the sensor is arranged to open the control
circuit for the sensor 81 when this occurs. In other words when the
sensor 82 "sees" a light in the mirror 83 instead of a diaper, the
glue guns 50 are rendered inactive.
INITIAL FOLDING SECTION
As mentioned above, the diaper blanks are preliminarily folded
across a transverse fold line 26a. This is accomplished in the
initial folding section 33 by the cooperative action of the folding
boards 51 and folding bars 52. This sequence is shown in
perspective in FIG. 5 and in side elevation in FIG. 6. Reference
may also be made to the additional views of the folding boards in
FIGS. 3, 7 and 9--11.
Each of the folding boards 51 is a composite structure made up of
elements which include an upper triangular forming surface 90 and a
lower triangular forming surface 91 having a centrally located slot
92. The upper and lower forming surfaces are secured to a
transverse web member 94 which extends between a pair of end blocks
95. Each end block carries a pair of rollers 96 adapted to travel
in a guide channel 97 (see FIGS. 5 and 7) secured to the machine
frame. The rollers 96 are preferably journaled on shafts 98 having
their inner ends bolted to the end blocks 95 and their outer ends
secured by link brackets 99 to a roller chain 100 located on either
side of the forming board 51.
The roller chains 100 are trained over an idle sprocket 101 (see
FIGS. 1a and 3) and over a drive sprocket 102 (see FIGS. 1b and 18)
mounted on shafts 103, 104 journaled in bearings on the machine
frame. The shaft 103 for the idle sprocket 101 is preferably
adjustably mounted to provide for adjusting the tension of the
roller chain. The shaft 104 for the drive sprocket 102 is driven
from gear case 45 by a suitable timing belt or chain. The folding
boards 51 are thus moved about a closed loop 105 in the direction
indicated by the arrows 106 in FIGS. 1a and 1b.
A substantial portion of the lower reach of the loop 105 is
disposed parallel to and in close proximity to the conveyor belts
61, 63. Also the timing of the folding boards 51 is such that they
are sequentially brought into engagement with the rear portion of
the diaper blanks 26 on the belts 61, 63 after the blanks have been
spaced apart by the speedup belts 72, 73. The left hand folding
board 51 shown in FIG. 6 is in the position just described.
With further reference to FIG. 6, it will be seen that each of the
folding bars 52 in the illustration machine 25 is carried about a
continuous loop 109 defined by a pair of laterally spaced roller
chains 110 trained about adjustable idle sprockets 111 and drive
sprockets 112 mounted on shafts 113, 114 journaled in bearings on
the machine frame. The drive shaft 114 is connected to gear case 43
through a suitable drive chain 115 and sprocket 116 (see FIG.
7).
In the preferred embodiment, each folding bar is of T-shaped
construction with a leg 117 connected by a cross pin 118 to the
roller chains 110. A leg brace 120 is also connected by a crosspin
121 to the roller chains 111 and to the leg 117 adjacent its
midpoint by a bolt 122 to hold the folding bar 52 in outwardly and
rearwardly inclined relation relative to the direction of chain
movement as indicated by arrows 123.
The disposition of the loop 109 is such that the T-bar portion of
the folding bars 52 follow a path which intersects the lower reach
of the forming board loop 105 as the folding bars move along the
upper reach of the loop 109. It will be noted that the folding bars
are disposed centrally between conveyor belts 61, 63. Also, the
movement of the folding bars is timed so that they each are
positioned below and ahead of one of the folding boards 51 as they
begin to travel along the upper reach of the loop 109. Then, due to
the inclined disposition of the loop 109, each of the folding bars
52 engages the underside of one of the diaper blanks 26 and begins
to lift it with respect to the leading edge of its folding board
51. In addition because of the slower movement of the folding bars
52 relative to the folding boards 51, the leading portion of the
diaper blank is draped back over upper forming surface 90 of the
folding board 51 (see FIGS. 5--7). This folding action is further
assisted by upper edge guides 125 secured to the machine frame
which press the (formerly leading portion of the) diaper blank 26
over the upper forming surface 90 of the folding board (see FIG.
5).
To prevent the folding board 51 from completely overtaking and
interfering with the folding bar 52, the latter is quickly swung
out of the path of the folding board. This is accomplished in the
preferred embodiment by the increased forward component imparted to
the folding bar as it travels around the end of the loop 109
defined by the drive sprockets 112 and due to the shortening of the
distance between crosspins 118 and 121 as this takes place.
Before leaving the initial folding section 33 it should be noted
that the sensor 81 for the glue guns 50 is located in this section
of the illustrative folding machine 25. As seen in FIG. 6, the
sprocket drive shaft 114 also drives a shaft 130 through a suitable
timing belt or the like which is shown only schematically. Mounted
on the shaft 130 is a disc 131 having a pair of apertures 132 cut
in it (only one of which is shown). A photocell 133 is mounted on
one side of the disc so that as the apertures 132 pass by the cell
"sees" light from a light source 134 mounted on the other side of
the disc in alignment with the cell. The signal from the photocell
is then amplified and utilized to energize a solenoid valve in the
pneumatic circuit of the glue guns 50 in a known manner.
Since the disc 131 is ultimately driven from the main drive motor
39 which also controls the speed movement of the diaper blanks 26
on the conveyor 38, rotation of the disc is maintained in timed
relation to the movement of the diaper blanks. However, in order to
precisely locate the glue spots relative to the transverse fold
line 26a suitable adjusting means are desirably provided in the
sensor mechanism. To this end, the photocell 133 and light 134
source are both mounted on a common bracket 136 rotatably mounted
on an shaft 137 coaxial with the shaft 130. By rotating the
bracket, application of the glue spots may be advanced or retarded
relative to the center fold line 26a. Rotation of the shaft 137 is
accomplished through a belt 138 trained around a pulley on the
shaft 137 and another pulley on a control 139 shaft fitted with a
knob 140. The distance between glue spots is fixed by the arcuate
distance between apertures 132 in the disc 131. The amount of glue
discharged by the guns 50 at each spot can be suitably controlled
by a timer (not shown) in series with the sensor and the guns to
control the "ontime" for the guns incident to each actuation.
SIDE TUCKING SECTION
In keeping with the invention the portions of the diaper blank
located along the center fold line 26a outboard of the center 26b
are interfolded to form a body-conforming diaper such as
illustrated in FIG. 14. For this purpose the folding boards 51 are
provided with additional forming elements including a pair of side
tuckers 150 and a pair of intermediate forming edges 151 located
between the upper and lower forming surfaces 90, 91. As shown in
FIG. 9, the forming edges 151 are defined by the forward edges of a
pair of plates 152 and include a substantially straight line
portion 151a which intersects the legs of the triangular forming
surfaces 90, 91 at substantially a right angle and an arcuate outer
portion 151b which extends outwardly from the surfaces 90, 91.
Each of the side tuckers 150 includes a forward forming arm 155
pivotally mounted on one of the end blocks 95. The forming arms are
of doubled back configuration adapted to swing around the plates
152 and between forming surfaces 90, 91. Each side tucker 150 also
includes an operating arm 156 which carried a cam follower 157
adapted to ride along a cam surface 158 secured to the machine
frame and a return arm 159. A spring 160 connected between the
return arms of a pair of the side tuckers 150 for each folding
board 51 normally biases the cam followers 157 against the cam
surface 158.
After the diaper blanks 26 are preliminarily folded over the
folding boards 51 by the folding boards 52 in the initial folding
section 33, the blanks are carried on the folding boards into the
side-tucking section 34. Referring to FIG. 12, the folding boards
51 are moved from left to right by the roller chains 100. As the
followers 157 engage the cams 158, the tucking arms 155 are swung
inwardly engaging the material of the diaper blank along the center
fold line 26a on either side of the center 26b. The progressive
inward movement of the tucking arms 155 interfolds the material of
the diaper blank initially lying outboard of the center between the
upper and lower forming surfaces 90, 91 and over the intermediate
forming edges 151.
Completion of the side-tucking and interfolding operation occurs
when the tucking arms 155 reach the position illustrated in FIG. 13
and the corresponding location in FIG. 12. At this point the
tucking arms 155 have been swung to their inner most positions by
the cams 158 and the followers 157 on the actuating arms 156. With
the tucking arms in this portion, the diaper is firmly folded under
the legs of the triangular shaped upper and lower forming surfaces
90, 91 along diagonal fold lines 27a and 27b, respectively. In
addition, the material of the diaper blank initially lying along
the center fold line 26a adjacent the edges of the blank has been
drawn over the arcuate portion 151b of the intermediate forming
edge 151 and is folded over the straight edge portion 151a of the
intermediate forming edge. This results in reversely interfolding
each side of the diaper blank 26 along crease lines 27c and 27d to
form the leg engaging portions D.
Once the diaper blank 26 has moved into the side-tucking section 34
it is no longer supported by the conveyor belts 61, 63 (seen in
phantom at the left of FIG. 12). Instead the underside of the
diapers are supported by a flat upper surface 161 of the cam 158
and the upper side of the diapers are engaged by a holddown bar 163
located above the path of the folding boards 51. The sliding
friction between the diaper blank and the holddown bar 163 and
plate surface 161 keep the blank tautly stretched over the upper
and lower forming surfaces 90, 91. It will also be understood that
the final location of the inner tips of the tucking arms 155 is
such that sharp crease lines 27c and 27d are formed in the blank
without necessitating engagement of the tucking arms along the
entire length of these crease lines. Indeed, in the preferred
embodiment, the tucking arms are relieved inwardly of their tips in
order to avoid engagement of the tucking arms with the previously
applied glue spots.
Upon completion of the side tucking operation the tucking arms 155
are swung out of engagement with the interfolded diaper by the
biasing force of the spring 160 as the cam followers 157 move
inwardly on the receding cam track 158. The folded diaper 27, is
however, retained on the folding board 51.
PICKOFF SECTION
FIGS. 15a--21 illustrate the details of the picker pins 54 in the
pickoff section 35, as well as further details of the loop 105 of
the folding boards 51 and details of the stripping and discharge
section 36. Each of the picker pins 54 is of substantially L-shaped
configuration with its long leg projecting forwardly in the
direction of picker pin travel indicated by arrows 165. The short
leg of each picker pin 54 is bolted to a bracket 166 mounted on a
pair of cross pins 167, 168 secured at their ends by links 169
forming part of a roller chain 170 on each side of the pin 54.
Each of the chains 170 is trained over a drive sprocket 171, a
return sprocket 172 and an idle sprocket 173 mounted on shafts
174--176 journaled in bearings secured to the machine frame. The
drive shaft 174 and drive sprockets 171 are driven from gear case
46 by a suitable timing belt or chain and the bearing for the
return shaft 175 are preferably adjustably mounted on the machine
frame to control the chain tension. The upper and lower reaches of
chain travel are also preferably supported by guide surfaces 177,
178 secured to the machine frame.
As seen in FIG. 15a, the path of travel of the picker pins 54
between the return sprockets 172 and idle sprockets 173 is inclined
upwardly from below the folding boards 51 such that the picker pin
path intersects the folding board path at an acute angle. The
picker pins are centrally located between the roller chains 170 and
are timed to rise between adjacent ones of the folding boards 51.
From this point, the picker pins, due to their faster movement,
advance through the slot 92 in the lower forming surface 91 of the
folding board engaging the folded diaper 27 and carrying it off the
folding board. This sequence is illustrated in FIGS. 15a, 15b and
18 and it will be seen that the diaper is completely removed from
the folding board prior to the folding board being carried up and
around sprockets 102 by the roller chains (see FIGS. 18 and 19). To
insure that the diapers stay on the picker pins as the folding
boards are lifted away the sprockets 102 also carry web members 180
having depending feet 181 which engage the diapers.
STRIPPING AND DISCHARGE SECTION
As the diapers move past sprocket wheels 102 on the picker pins 54,
they also move off the upper supporting surface 161 of the cams 158
and between guide surfaces 182 and 183 secured to the machine frame
(see FIGS. 18, 20 and 21). The stripping elements 55, in this case
a pair of laterally spaced pins, are mounted on cross pins 185
which are secured at their ends by links 186 forming part of roller
chains 187 on each side of the stripping elements. These chains 187
are trained about drive sprockets 188 and adjustable return
sprockets 189 such that the lower reach of the chain is located
parallel to and just above the upper reach of the chains 170. The
drive sprockets 188 are mounted on a drive shaft 190 journaled in
bearings secured to the machine frame and driven through a suitable
timing chain from gear case 47. Due to their faster speed the
stripping elements 55 overtake and straddle the picker pins 54 and
carry the diapers 27 forwardly off the picker pins.
Adjacent the drive sprockets 188 the diaper is discharged onto a
short transfer conveyor 191 and then between compression rolls 56,
57. The transfer conveyor 191 and the rolls 56, 57 are driven from
drive shaft 190 by a suitable chain and sprocket arrangement such
as shown in dash lines in FIG. 20. The compression rolls 56, 57 not
only serve to flatten the prefolded diapers somewhat thereby
creasing the fold lines but also help to insure good contact
between the interfolded areas of the diaper and the spots of
adhesive (see FIG. 21). The folded diapers 27 are then discharged
down chute 58 and onto conveyor 59 for delivery to suitable
packaging equipment (not shown).
While the invention has been described herein in connection with
certain preferred methods and apparatus we do not intend to limit
the invention to the specific procedures described or embodiments
shown. On the contrary, we intend to cover such alternative and
equivalent methods and apparatus as fall within the spirit and
scope of the appended claims.
* * * * *