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Oct- l, 1945»
T.' L. JoHNsoN
2,408,398
MULTIPLE EX'VL‘RUSION
Filed July 24, 1945
/07
/4058 /Jb
\vM7
4/44
INVENTOR.
il??
Patented Oct. 1, 1946
2,408,398
UNITED sTATss PATENT orrlce
2,408,398
MULTIPLE EXTRUSION
Theodore L. Johnson, St. Louis, Mo.
Application July 24, 1943, Serial No.y 496,258
l
20 Claims. (Cl. 18--13)
l)
severing exact lengths of linearly extruded ma
terial. to assure delivery of articles of predeter
mined finish dimensions.'
The foregoing and numerous other objects will
ized by dissimilar body and core portions, for ex
more clearly appear from the following detailed
ample, lead pencils and any other composite
description of certain apparatus and methods of
products characterized by differing internal and
production realizable through the use thereof,
external elements, at least certain of which are
particularly when considered in connection with
formed of setting plastic materials,
Heretofore, as far as is known to this appli lu the accompanying drawing, in which:
Fig, l is a fragmentary vertical sectional ele
cant, methods of forming articles or products of
vation
of a preferred form of compound extrusion
an attenuated nature, and involving the useof
apparatus adapted particularly for use in the
extruded thermo-plastic or thermo-setting ma
manufacture of lead pencils;
terials, have been coniined to the production of
2 is a fragmentary longitudinal sectional
articles of homogeneous nature by extrusion of 15
View through a portion of the forming or molding
a single plastic material. There exists a need,
passageway of the device of Fig. 1;
`
and may be developed numerous additional mar
Fig. 3 is a vertical, transverse, sectional eleva
het possibilities, for forming entirely by extrusion
tion, as viewed along the staggered plane indi
methods a great variety of articles by compound
cated at 3-3 in Fig. 2;
y '
This invention relates to improvements in mul
tiple extrusion, and more particularly t0 methods
of and apparatus for producing by extrusion
processes, certain composite articles character
4M
extrusion. i. e., a method or process through the 20
Fig. 4 is a single line drawing, somewhat dia
practice of which dissimilar plastic materials may
grammatic in nature, and showing in general ar
be extruded internally or externally of each other.
rangement, a side elevation of a machine em
The present invention accordingly has a major
bodying a plurality of the assemblies of Fig. 1, a.
objective, of perfection of compound extrusion
magazine feed arrangement for insert elements
practices.
25 as shown by Figs. l and 8, being omitted from
Yet another object of the invention is attained
this ligure in the interest of clearness;
in an improved method and arrangement of ap
Fig. 5 is a top or plan View of the apparatus of
paratus for applying to a linearly extruded prod
Fig. Ll;
uct, a permanent inset or insert member, bonded
Fig. 6 is a fragmentary side elevation of an
say to an elongate body of plastic or intimately 30
assembly
utilized in connection with the struc
united therewith as an incident to the extrusion
ture of Fig. l, for operating a cutoff gate and feed
process. One example of such application is
structure employed for the insertion of inset
found in the provision of automatic means to be
members,
such as erasers introduced in the line
described, for introducing an eraser element
molded into union with the body of a lead pencil; C@ lil of dow of material to form pencil bodies, this fig
ure showing'further a diagram of a control cir
another example is objectively realized in the in
cuit
constituting a part of a flow gauge assembly;
troduction, say, of metal pipe connections or the
Fig.
7 is a' fragmentary sectional view taken
like, into lengths of plastic tubing, whereby the
lengthwise through a plastic tube and coupling
latter may be formed by a continuous extrusion
process complete with couplings or connections 40 as"embly. such as may be produced by the assem
blies of Figs. l, 4 and 5;
ready for assembly at the place of usage. Fur
8 illustrates an arrangement utilized inthe
ther numerous examples of possibilities within
production ci a composite elongate structure
the present instructions will suggest themselves in
characterized by an inset element or elements,
1xeeping with the present object.
for providing an intermittent feed for such ele
Still another object of the invention is attained
ments, for examples, the couplings of a plastic
in an improved arrangement for applying a coat
ing material externally to an elongate extruded
plastic product or articie, for example7 a lubri
cant to facilitate passage of an extruded body of
plastic through a forming chamber; the appli- r
cati-on say of a plastic finish coating, or an ena
mel or lacquer to a body or article of elongate or
tubing or pipe, or the eraser elements of an
eraser-pencil combination, and
Fig. 9 is a fragmentary longitudinal sectional
view of an eraser and the head end of a plastic
booîy pencil, showing a preferred manner of
eraser assembly.
Referring now to the drawing, the assembly >
other desired practical shape.
shown by Figs 4 and 5 may constitute an attach
A still further and important object of the in
`vention is attained in improved equipment for 55 ment for any standard extrusion machine, many
suitable types of which are available to the trade,
2,408,398
3
such as the extrusion machines manufactured
by National-Erie Corporation'of Erie, Pa. Since
sion machine, and connected parts of present
passage-forming structure or body of the ma
chine, is a conduit 84 which is provided with an
upwardly extending branch portion 85, these serv
ing with provisions later described, for the sup
ply of a coating material to the body of plastic
mix or the like extruded into and proceeding
, through the one or more passages 1S.
Provision is made for manually displacing the
support 1| and parts carried thereby, in a longi
tudinal direction on the bed plate i9, as through
a hand wheel B9 provided with a threaded shank
pera-ture control iiuid or provided with electrical
heating provisions (not shown) in any suitable or
conventional arrangement.
In the interest of brevity of illustration and de
scription, most of the various temperature, pres
sure, and flow-control instruments and gauges
have been omitted since, except for those later
81 the inner end of which (not shown) is ro
tatably positioned in, but axially secured to an
end portion of member ‘il and threaded through
an upwardly projecting arm portion of member
19., As best appears from Fig. 1, the passage
forming structure is capped at its input end,
by a closure member 99 provided with a tapered
socket 9|, with which- interfits a similarly ta
to be described, they are or may be of conven
tional and well known type. It is however im
portantly to be noted that, in the interest of
provision for complete accurate visual informa
tion of the operator at all times, it is contem
plated that the various temperature and pres
pered end of a nozzle extension member 92 con
taining an entrance throat or nozzle proper 93.
sure control expedients will be employed in con
nection with present apparatus similarly to those
described and shown in my copending applica 25
tion relating to continuous molding, tiled June
9, 1943, and bearing Serial No. 490,387.
Among the numerous practical realizations of
the compound extrusion method heretofore de-.
scribed in part, and later to be described more
fully, is the manufacture of so-called lead pen
cils, wherein the body or sheath of the pencil
may be formed of one thermo-plastic or thermo
plastic-containing material, and the writing core
or “lead” may be formed of a dissimilar extruded
material expressed Vwhile in plastic state from a
Disposed in a
suitable location preferably as shown, along the
the extrusion machine is or may be conventional,
and of itself forms no part of present improve
ments, only the discharge end of the extrusion
chamber or casing 91, and extrusion screw |00,
are shown. The casing structure of the extru
structure may be jacketed (not shown) for a tem
4
for a purpose later appearing.
A plurality of the nozzle members 92 are pro
vided as will appear from Fig. 5, and each of
these is supplied with a material M3, which in
pencil manufacture is thermo-setting or thermo
plastic in nature and which will be supplied to
vthe several members 92, in a multiple unit, from
a manifold member 94. The manifold 94 is pro
vided with a short tapered receiving throat 95
which is fed as by a receiving neck 96, and the
latter attached as by a flange connection to the
discharge end of an extrusion machine 91 pro
vided with a screw |90.
The machine 91 is or
may be the National-Erie assembly earlier men
tioned, although any suitable or conventional ex
suitable orifice.
trusion apparatus of suñìcient capacity will serve
this purpose.
illustrating an assembly of apparatus for pencil
Disposed to extend preferably vertically of the
40
manufacture. As will appear from Fig. 4, a pre
manifold element 94, is the second or auxiliary
Reference will now be made to Figs. 4 and 5,
ferred form- of this assembly includes a station
ary bed plate 10 on which is slidably disposed
for a limited longitudinal movement, a base 1|.
The bed plate 1D and superposed structure are
conveniently carried as by a ‘table '|2 provided
with legs or other suitable subjacent supports 13.
The body of the apparatus mounted on sup
port 1l includes, primarily, a passage-forming
structure comprised» of an upper half 14 and a
lower half 15, each provided in the present in
» stance, with a substantially semi-cylindrical lon
gitudinal groove, the two grooves when adiacent
ly disposed, serving to form a passageway 'it
which constitutes a forming conduit for the plas
tic material extruded as hereinafter described.
It is preferred, as shown by the present assem
bly, so to form the members 14 and 15 that each
thereof comprises a plurality of grooves, . and
hence when paired in assembly, serve to form a
plurality of the passageways 16. In the assem
bly of Fig. 4, the passage-forming structure is
surrounded, or partly so, by a heating chamber
-|'| near the entrance end of the structure, and
by preference with a cooling chamber 89 extend
extrusion apparatus identiñed with a feed chan
nel IBI and an extrusion screw |92, which is
supplied from an extrusion chamber (not shown),
the member |9| opening into a common second
ary extrusion conduit |93 (Fig. 1) connected to
which are the requisite plurality of elbow iit
tings |94 each provided with a detachable nozzle
element |95. The several secondary nozzles |95
are each provided with an attenuated, finely
bored extension |95 which, as seen from Fig. 1,
extends outwardly to the end of the extension
member 92 beyond nozzle 93, and by preference,
projects fully through the tapered joint-forming
connection at 9|. It will readily appear from
Fig. 1 that the trend of the element |96, hence
of the bore therein, is concentric or coaxial in
relation to the passageway in member 92. lt
results from this structure that actual extrusion
of material from member |95 of the secondary
extrusion feed, occurs considerably later than,
and beyond the time and zone of extrusion by
nozzle 93 into member 92.
A number of advantageous cleanout facilities
65 for the manifold assembly 94, and the several
ing about the discharge end of the passage-form
passage-forming elements therein, are provided
ing structure. A threaded clamping device, in
for ease of access to all parts of the interior of
dicated generally at 8|, is employed to hold in
the structure; for example, at each side of mem
assembly, the upper and lower half of the struc
ber 94 there is provided a removable cover plate
ture identiiied in part at least, by members 'i4
70 ‘ì01 (Fig.4).
and 75.
Referring now more particularly to some of
At each end 0f the assembly there is carried
the features illustrated by Fig. l, and the general
on the structure described, a bracket projecting
method involved in extrusion practice identified
endwise of and upwardly from the body forming
therewith, it will now have appeared that the
the several passages 16, one such bracket being
material M3 impelled under pressure by screw
75
indicated at 82 and the opposite bracket at 83,
5
2,408,398
|00 through member 94, via each nozzle 93 and
nozzle passage 92, will proceed through one of
the openings or passages in a gate member |09,
thence into passage 16. It is preferred, but not
in all cases strictly necessary, that the setting
plastic material M3 be permitted to cool or other
wise to set somewhat by the time it, reaches the
passage in gate |99, available thereto and later
to be described. It results from this that the
material indicated for reference as M4, upon be
ing impelled nrst downwardly in passage |03,
thence outwardly through nozzle member |05 and
through the `pore in member |06, will be extruded
into the partly set, body-forming portion of the
pencil or the like.
It may here be noted that, as to choice of ma
terials, a thermo-setting plastic is admixed with
a. high proportion of ñnely comminuted wood
iiour together with asbestos liber or other fibrous
material. The plastic may also consist of a ma
terial of cellularly-expanded nature, the propor
tion of plastic being sufliciently low that the re
sulting pencil body will not warp, presents a
smooth iinish, and may easily be sharpened in
conventional pencil sharpening devices, and so is
also of such characteristics that it can readily be
cut or shapened by knife.
Although the various and numerous possible
compositions of matter suitable for body or sheath
of the faces of the body of the pencil body, suit
alble legends or indicia indicating grade, manu
facturer’s name, tradename, etc. Provision for
this purpose is made in the present assembly
through a series of endless tapes or bands, there
being one such band indicated at | I9 for each of
the passages i6. The band enters the related
passage through a sloping passageway |||, and
moves in the direction of the arrow (Fig. 1).
Each such band proceeds through and then
emerges from the discharge end portion of the
passage 16, whence it diverges from the now
formed pencil body and moves over a friction
roller H2, journalled in the bracket 83, thence
rearwardly above the machine, this returning
pass of the band or tape being indicated at ||3
and moving in the direction of the arrow (Fig.
4).
'I'he band thence moves over a companion
I.friction roller H4, thence downwardly at an
acute angle and again into the passage |||. In
the multiple unit shown by Figs. 4 and 5, each
pair of rollers ||2 and ||4 serve a plurality of
the tapes or bands ||_0 as will readily appear
from the top view of Fig. 5. It is a preference
to provide each of the rollers |I2 and ||4 with
a friction surface, and to control and to assure
a carefully timed movement of the several tapes
l l0, there is provided a longitudinally ribbed roll
||5 overlying the tapes and roller I|2, and a
of a pencil, and others suitable for the core or 30 similarly ribbed roller H6 overlying the roller
lead, do not of themselves constitute any part of
| |4. A friction control, operating through varia
tion of spacing of the paired adjacent rolls, is
noted for completeness and to provide a few ex
provided on each bracket 82 and 83, and identi
amples, that the pencil sheath may be constituted
lied with control elements H1.
as disclosed in Patent No. 1,937,103 to J . R.. Thom 35
It is contemplated and entirely practical to de
sen, Nov. 28, 1933', and entitled Pencil sheath
rive
the motion of the several tapes H0, each
composition.
through the friction between the tape and the
The material M4 from which results the so
material M3 in the associated passageway 16, it
called “lead” of the pencil will preferably consist
fbeing understood that the material in passage 'I6
the presently claimed improvements, it may be
of a high percentage of graphite or plumlbago of 40 remains under an appreciable pressure through
out the movement of the plastic through this
passage. However, when operating at lower ini
a suitable proportion of a self-hardening plastic
tial pressures andv with certain alternate choices
or other material. To provide certain tried eX
of materials, it may be desirable to power-drive
amples of suitable compositions, these may con 45 the tapes or bands, as by roller H4 for example,
sist of mixtures of the general nature disclosed
whereby to impart, by means externally of the
in Patent No. 1,937,105, Thomsen, issued No
extrusion channels, a predetermined and fixed
vember 28, 1933, and entitled Self-hardening
rate of movement to the several tapes HD. With
graphite lead for pencils; the compositions of
this alternative, the roller | I4 may be considered
Thomsen are, however, modiñed, for applicant’s 50 as a power drive element, operating through ten
purpose, to minimize or obviate the permanently
sion on the several tapes, to draw same into,
flexible characteristic of Thomsen’s products, by
thence through the several passageways 1S.
eliminating substantially all 0f those ingredients
In the manufacture of elongate articles such
which make for flexibility of ñnished product.
as lead pencils it is frequently desirable to make
Applicant desires, after setting of the material ,_ provision for application to the body of the arti
forming the writing core, a relatively rigid core
cle, of a coating material, this term being used
or lead, which may be attained as directed, and
in a broad and generic sense, to include, for eX
yet provide an easily extrusible material which is
ample, a lubricant to facilitate passage of the
capable of forming into ñnal position under rea
plastic through the remainder of its forming pas
sonable pressures.
sage, such as T6, whereby considerably to reduce
In the passage '16, in case a pencil of polygonal,
the pressure necessary otherwise, for overcoming
say hexagonal section is desired, all or a certain
friction, to be maintained at nozzle 93 and rear
deñned portion of the length of passageway 16,
wardly thereof in the course of dow; other coat
is so formed as to pro-vide three faces of the
ing materials include for example an enamel,
hexagon structure in member 'l5 and the addi
- tinted lacquer, paint or the like, and as a still
tional three faces in a companion groove of mem
further group of possibilities, a surface coating of
ber 74„this arrangement being suggested by the
yet an additional plastic material. In prevail
section of Fig. 3. The same arrangement will
ing extrusion practice, lengths of forming pas
obviously apply equally to any other multi-sided
sages beyond the nozzles are restricted, since ex
structure, or any other polygonal section de
cessive lfriction in a longer passage would require
sired.
inordinate extrusion pressures. It results that
As a convenient adjunct to or step- in the com
many extruded articles are necessarily discharged
plete automatic or semi-automatic manufacture
while insufliciently set to be self supporting;
of lead pencils by compound extrusion, there is
hence the provision for application of a lubri
provided an arrangement for impressing on one
cant, chemically compatible with the plastic, en
predetermined texture and iineness according to
grade of pencil desired. With this is admixed
2,408,398
7
ables a much longer forming passage and vbetter
physioalintegrity of the finished articles.
'
" Provision for the application of desired coat
ing materials may be made according to the ar
rangement shown vby Figs. 2 and 3. Somewhat
beyond the portion of Vpassage le as shown‘bt7
Fig. l, for example in the zone lengthwise of
passage 16 identiñed by conduits 04 and 85, the
8
ings therefor in member 15. Member 00 is pro
vided,~ asheretofore mentioned, with> the tapered
seating aperture 9| for sealing engagement with
the tapered end of member S2, and by reason of
this provision the entire structure which is slid
ably mounted on the bed plate 10, may be moved
away from the one or more members 02 for serv
ice attention, cleaning, replacement of parts or
the like. Member 90 is further secured across
members "I4 and l5 are each provided with a
transverse conduit or passageway, indicated at 10 its upper margin by a locking bracket |24, se
cured inf place on member 'i4 as by screw or
|20 in member 74, and |2| vin member l5. Each
screws |25.v It will appear that between mem
ofthe passages |20 and |2| is formedin the ex
ber 90 and the adjacent end lfaces of members
ample shown, to provide three initially diver
'i4 andY 15, there is provided one or more spaces
gent branches, which'thereafœr are brought into
each in the nature of a crossheador guide with
converging relation as shown by Fig. 3,50 that
in which the gate |09 is vertically re'cpirocably
there are sixl passages or openings directed into
movable, the guideway for the gate being gener
the passageway le, each of these six branch pas
sages delivering substantially centrally of one of
the hexagonal face portions of the body of plastic
later resulting in the pencil body. It is further
preferred so to form the inner terminal or mouth
of the several branch passages that each thereof
is deñected forwardly in relation t0 the line of
flow in passage lâ, say at an angle of 45 de
grees, as clearly appears from Fig. 2.
'
It will now» appear obvious as desirable to pre
ally indicated at |20. The gate member |09 is
provided with a pair of through passages one of
which is the passage l 08, and the second of which
is a similar passage |27. Preferably each of these
passages through the gate is of even diameter or
other cross section, with passage 1E, so that the
gate in the position shown in Fig'. 1, or in its
opposite extreme position, provides for continuity
of passage of the material M3 ahead of, throug
vent the material under considerable pressure in
the forming passageway lâ, from finding an exit
through the passageway |20 or |2|, and to this
and beyond the gate.
The gate |09 serves as a cutoff or severance ele
are preferably light spring metal elements, each
of pins or trunnions each projected horizontally
ment so as to determine the length of the linear
end there are provided, one at the inner end of 30 plastic body in the extrusion passage beyond the
nozzle, which is to be devoted to an -individual
'each branch passage, a spring check or gate ele
unit, such as a pencil. The cutoff operation of
ment |22, a similar provision being noted at the
the gate |00 is effected by the provision of a pair
inner end of passage ||| for tape H0. These
anchored Yas by 'welding or other suitable form 35 from one side of the gate and one of which ap
pears in Fig..6 as indicated by the numeral |30.
of securernent,` at its end most remote from the
At each side of the gate there is provided a hori
free end which is- in register with the several
-zontally reciprocable gate-actuating member |3I,
branches. v It is a- preference that the several
provided with a pair of diverging cam grooves
fingers or check elements §22 be staggered some
what along the passage 15 so as to avoid any 40 |32, in and along which operates the adjacent
trunnion |30. Reciprocable action of each Slide
possibility of interference with each other upon
13|, there being preferably at least a pair there
their opennig movement. As shown, it is pre
of. is veiîected through a crank arm |33, >pivotally
ferred that -each of the check members |22 be
connected at |34 to the member |3|, which is
mounted in a recess of a size just sumcient to
accommodate the individual element, whereby
to avoid any restriction of the normal cross sec
tional passage area in the region of introduction
of the vcoating material.v It is a preference, of
course, that the material introduced in accord
ance with the arrows shown by Figs. 2 and 3, f
through a single supply pipe 84, be maintained
under a pressure safely exceeding the order of
pressures obtaining in this region of the passage
16, so as to assure deñniteness of íiow direction.
` constrained to horizontal movement
through
-guides |35. The rod |33 is pivotally connected
to- a crank pin |36' on a crank disc |40, and the
disc rotatably supported by a shaft |4 | .~
Provision for a positive drive of the crank and
slide assembly at predetermined periods, 'is cur
rently shown as consisting of a motor .|42 sup
plied from a line |43, in one leg of which is a
switch |44. `
.
Reference has heretofore been made to the
Although the principal combinations and sub 55 general nature and one purpose of the flexible
band or tape ||0. Since the motion of tape ||0
cornbinations of features thus far described Will
directly follows the movement of the body of
suffice for the production of'elongate plastic ar
plastic> inïits advance through passage '16, ad
ticles in case, as in certain types of lead pencils,
vantage is taken of this fact to constitute the
vthe articles are formed of indefinite stock lengths
and separately cut to predetermined finished
lengths, it will nevertheless appear advantageous,
-first to gauge and secondly to sever the lengths
'prior to complete setting of the plastic material.
One mode of accomplishing this result is by
means of the gate' |09, heretofore merely gener
ally referred to. In the example selected, this
tape ||0 as one of the elements of a iiow gauge,
or linear` gauging means to determine the time
of cutoff actuation of gate |00. For this purpose
tape ||0 is provided with one or a plurality of
projections |45 extending depthwise of passage
|||, it being noted in passing that each projec
tion |45 is of just a depth and area so that in its
function is accomplished by gate |00, there being
movement through passage |||, it serves at all
>and operating transversely thereof.
each of the one or more elements |55 engages
times to keep the passage clear of any accumu
preferably one gate for each compound nozzle
lated plastic or other materials.
assembly and passage TS, or alternately, a gate
Thetiming of this assembly is such that as
structure common to the plurality of passages 'I6 70
the ,switch- |44 (Fig- l)` the circuit to motor |42
By reference to Fig. 1 it will be seen that the
is completed and held closed for a suiñcient in
>closure member 90 is somewhat L-shaped in
terval to actuate the gate |09 through a complete
form, and is secured as through aplurality of
lscrewsIZS, extended into suitable tapped open 75 stroke in one direction, and in so doing there ob
2,408,398
~
9
viously results a severance of or interruption in
the passage 15. It will be noted however that
the gate serves to remove from the passage, a
short core or slug of the plastic material which,
as shown in Fig. i occupies the opening |58. This
slug is expelled to the right (Fig. 1) into one of
a pair of scavenging passages |45. Suitable
means for keeping the conduits M5 clear of the
10
and hence of eraser feed action as attained
through the cooperative engagement of elements
|45 and switch |44, is such that these events are
conducted in a deñnite cycle and are spaced in
respect to extent of linear flow of material in
passage 15 so that the finished pencil and eraser'
combinations as ejected from the right hand end
of the assembly of Fig. ll, are all of a uniform
accumulation resulting from the short cores or
length. It may here be noted that the assembly
slugs, may consist of a small screw or the like 10 is preferably provided with one or a plurality of
(not shown) operating in each passage.
apron elements |55 at the delivery end of the ma
In the production of lead pencils it is obviously
desirable to avoid added operations heretofore
required for the application say of a ferrule and
eraser element to the head of the pencil body.
According to the present method and structural
improvements, advantage is taken of the recip
center conveyor indicated at |55, operating over
a roller or pulley |61, and moving in the direction
eraser elements whereby to bring them, one at
a time, into the forming bore 16 and into align
ment with this passage just following the cutoff
aging station.
In certain installations it is desirable to pre
chine, and disposed in virtually the same plane
as the aprons |65, is the upper pass of an ofi
of the arrow (Fig. 4). The conveyor may be
utilized to deliver the now-ñnished units, say
rocal action of gate |09 and the provision of the
through a cooling duct or through a quenching
paired passages |88 and |21 in the gate, to uti
zone and thence to a suitable situs of further
lize the gate as a charging device for individual 20 drying or setting if necessary, thence to a pack
clude any reverse movement of rack |51, as might
occur because of the inherent compressibility of
preferably just slightly smaller in diameter than 25 the string of eraser elements, in case the ap
the short passages mii-_|21 so that the erasers
propriate gate passage is not exactly aligned with
may be impelled, one at a time, into one or the
passage |155 or |5|. Any such reverse rack move
other of the passages through the gate, there
ment is precluded by a pawl |68, pivoted to a
after upon reciprocal movement of the gate, to
stationary element of the assembly as through a
be brought in the line of flow of the plastic. For 30 pin | 62, a suitable small torsion spring |69A being
this purpose, member B5 is provided with a pair
carried by the pin |59 and mounted to bias the
of preferably drilled passages |55 and |5| di
pa-wl point toward the teeth of rack |51.
rected into each of which is a conduit or eraser
The function and method identified with the
feed tube |52, each of these tubes containing a
apparatus of Figs. l through 6 have been ex
string of lightly connected eraser elements |53.
plained heretofore in the course of description of
The feed tubes |52 and mechanism associated
parts, their inter-relation and. function, and hence
therewith, are omitted from Figs. 4 and 5, in
the operation is now thought to be fully appar
the interest of clarity of illustration of major
ent.
elements, but these parts are clearly shown by
It will have appeared from Fig. l that the form
Figs. l, 6 and 8. It will now be obvious that 4:0 of eraser employed in connection with the pres
upon imparting pressure to each of the strings
ent method of eraser attachment and pencil as
of erasers |53 in a direction to the right (Fig. 1)
sembly, has been particularly adapted to avoid
an eraser element will be impelled into whichever
any necessity of a separate ferrule or like eraser
of the passages |58 or |21 is in line with its asso
holding element. To this end, each of the eraser
ciated feed passage. At the same time, the eraser 45 units |53 is preferably formed as shown on an
operation described.
The eraser elements are
feeding movement hereinafter described, will
serve to eject the short core or slug of plastic
enlarged scale by Fig. 9, with an external cir
cumferential mortise undercut or shoulder por
outwardly to the right, into one of the scaveng
tion |16, the undercut nature of this peripheral
ing conduits |46. There will now be described
groove being such that this reduced end of eraser
the manner and timing of feed of the eraser units 50 |53 becomes embedded in and firmly embraced
to attain the result above referred to.
by a collar or annulus formed of the adjacent
It is a preference to rotate the crank disc |40
body of the plastic M3. Further keying secure
clockwise as indicated by the arrow (Fig. 6), by
ment between the eraser |53 and the pencil body
means of motor |152, thus resulting in a clock
is preferably provided for by provision of a cham
wise rotation of shaft Iêl. In case two of the 55 ber |1| internally of the anchored end of the
eraser magazine conduits |52 are employed, shaft
eraser, and a connecting neck |12 between the
|4| will be provided with a pair of double-tooth
bulbous chamber |1| and the body of the pencil.
`gear elements |55 the teeth of one of which are
The pressure on the material M3 in the forming
indicated at |54 (Fig. 8). Each of these teeth is
passages beyond the nozzle, is suiiîcient to cause
of rounded contour and serves, twice each revo 60 the material to enter the spaces |10, |1| and |12,
lution of shaft |4|, to engage one of a series of
to displace the air from these spaces and upon
teeth |55 on a rack |51, to one .end of which is
setting of the plastic, firmly to anchor the eraser
connected a link |60, and the latter connected
to the resulting pencil body, thus obviating any
to a plunger |5l. This plunger operates in a
necessity for a separate plastic or metal ferrule
tube |62 which is provided with a longitudinal 65 portion.
bottom slot |613, the tube |62 connecting directly
It is preferred that chambers | 1| and |12 be
with a tube |52 heretofore described. From this
made considerably larger in diameter than the
it will appear that, through the provision of a
extruded material IVI-«4, so that the resulting
pair of the gears |55 on shaft 14|, these gears
stem of material in these chambers consists in
being angularly displaced to locate their teeth 90 70 great part of the material M-S.
degrees apart, the effect of each rotation of shaft
The next preceding portion of the description
|4| is alternately to advance, through one eraser
has made particular reference to the manufac
length, the respective strings or supplies thereof
ture of plastic lead pencils, but it should be par
in the magazine tubes |52. Furthermore, it will
ticularly noted that the method is readily adapt
have appeared that the timing of gate actuation, 75 able, with or without merely minor changes, to
2,408,398
‘l l"
the Vformation of -other elongate articles provided
forming in rate of movement, to that of the iria'-`
in predetermined lengths or in indefinite stock
lengths, particularly those products which are ole
tachably assembled by nttings of various sorts
terial in the passageway.V
.
3. In apparatus for forming a rod-like plastic
article and inserting a permanent element into
the article, a nozzle, means for supplying plastic
in the nature say of metal inserts. One example
of a now-obvious extension of this technique is
material through the nozzle under pressure, a
passageway beyond the nozzle, a member movable
crosswise of the passageway and constituting a
indicated by Fig. 7 wherein there is shown frag
mentary lengths of a plastic tubing which is in
carrier for one or more insert elements, and
In such a structure, only a single 10 means for periodically actuating said movable
member to bring an insert element into the line
extrusion nozzle need be employed, and extrusion
of flow through said passageway.
.
is eiîected over say Va core element located in the
4. In apparatus for forming, and applying a
approximate position of member Hit (Fig. 1) ,
permanent insert element into a rod-like plastic
which may and usually would be of some greater
relative diameter than the member lilß. In the 15 article, a nozzle, means for supplying plastic
material through the nozzle under pressure, a
structure of Fig. 'l the tubing Iß? is shown as
itially extruded or cored so as to exhibit an an
nular section.
consisting of connected lengths in the finished
passageway beyond the nozzle, a member movable
gral eXtension of the associated connection. In
the production of a plastic tube and coupling as
sembly of this sort, the coupling elements |8| and
|82 will be alternately inserted into the forming
passageway by the alternate introduction, in en
length of said passageway, to effect operation of
transversely through the passageway and consti
article, a fluid-tight and structurally secure con
tuting a carrier for one or more insert elements,
nection between which is e?îected through a fe
male connection lSI and a male connection |82 20. means for actuating said movable member t`o
bring an insert element into the line of flow
threaded in the zone |83. Each of. the connec
through said passageway, and means operable re
tions |8| and |82 is provided with a thin rough
sponsively to the flow of material through aY given
ened prolongation |84 which constitutes an inte
suing operations of the gate lûâ, of the male and
female connections. In this case one of the tubu
said actuating means and member.
_
,
5. In plastic extrustion apparatus for forming
a composite elongate article, an extrusion nozzle,
means for supplying the nozzle with a plastic ma
terial under pressure, a passage beyond the noz
30 zle, and a combined cutoff gate and charging de
lar magazines IGZ-_|52 may be employed solely
ior male connections, and 'the opposite magazine
for female connections, whereby there is provided
vice for insert elements, arranged for movement
substantially crosswise of the passageway, and
adapted to interrupt the flow of plastic material
therethrough, and to bring an insert element into
for the alternate insertion of the two types of
connection at opposite ends of each deñned 35 the flow of material in said passage. ,
6. In plastic extrusion apparatus for forming a
length or unit of tube section.
composite elongate article, an extrusion nozzle,
It has been determined as desirable in the in
means for supplying the nozzle with a plastic ma
terest of minimizing finishing operations, When
terial under pressure, a passageway beyond the
utilizing certain types of plastic materials, to coat
or mask the insert elements such as the eraser 40 nozzle, and a combined cutoü gate and charging
device for insert elements arranged for movement
units |53 or pipe coupling units I8! and |82.
substantially crosswise of the passage, the gate
This may be done either by a readily removable
adapted periodically to interrupt the flow of plas
covering material of sheet form, or by application
tic material therethrough, and to bring an insert
of a liquid exteriorly of the insert units of such
element into the line of flow in said passageway,
nature as to prevent adherence of the plastic ma
and means for causing an effective actuation of
terial to the surfaces of the added elements.
said gate element, in response to a predetermined
Although the invention has been described by
extent of . movement of the plastic material
making detailed reference to but a few vapplica
through said passageway, said gate element be
tions of the method and modiiications of the
apparatus, the detail of description is'to be un
ing formed and normally positioned to permit a
substantially uninterrupted flow through the pas
derstood solely in an instructive and not in any
limiting sense, many variants being possible with
sageway between the periods of said interruption
in the scope of the claims hereunto> appended.
of flow.
,
I claim as my invention:
l. Ina device for forming and coating an elon- ,
gate plastic article, an extrusion nozzle, means
_for supplying a plastic setting material under
pressure through said nozzle, a passage beyond
thek nozzle, a conduit directed into said passage
and connected to a source of a coating material,
and a check valve in the zone of connection of
= '7. The herein described method ofiorming
lead pencil and eraser structure, which Yconsists
in simultaneously extruding into a common
forming passageway, a self-hardening plastic
material to form the body of the pencil and a
plastic material to constitute the core or writing
element of the pencil, in the form of a material
said conduit to said passage.
2,. In a device for the extrusion formation of
rod-like elements consisting at least in part of a
of self-hardening characteristics, and periodical
ly, responsive t0 a predetermined length of iiow
of the pencil forming materials through said pas
sageway, introducing transversely into said pas
plastic material, a feed nozzle, means for sup- »
sageway, an eraser element, and keying Vthe eraser
plying the feed nozzle with a plastic material un
der pressure, a passageway beyond the nozzle, a
cutoff element movable across the line of flow of
said material and operating through a portion of
element to the body of plastic in the passageway
said passageway, and means for causing eiîective ’
operation of said cutoiî element, in response to
a predetermined extent of linear movement of
the plastic material through said passageway,
while the body is in plastic state.'
.
8. The herein described method of forming
lead pencil and eraser structure, which consists in
simultaneously extruding into a common forming
passageway, a hardening plastic material to form
the body of the pencil, and extruding into said
passageway a plastic material to constitute the
said lmeans including an endless member movable
core or writing element of the pencil, inthe form
through a portion of said passageway and con 75 of a material of self-hardening characteristics,
13
2,408,3‘98
and periodically, responsive tothe length of flow
of the pencil forming materials through said
passageway,- introducing into said passageway, an
eraser element, keying the eraser element to the
body of plastic in the passageway while the body
is in plastic state, and timing the insertion of
14»
14. In'apparatus- for forming elongate articles'
by plastic extrusion, a nozzle, means for supply
ing the nozzle with a plastic material under pres
sure, a conduit beyond the nozzle for receiving
material extruded therefrom, a member movable
crosswise of the conduit and arranged periodi
cally'to sever the plastic material in said conduit,
sively to length of flow of the pencil body-forming
a now gauge for controlling operation of the sev
material in said passageway.
‘
9. An eraser assembly including a holding and 10 ering member, the iiow gauge including an encl
less nexible tape, movable with and positively
manipulating body of a -hardened thermo plastic
impelled by the plastic in said conduit, and one
material, and an eraser having a recess opening
or
more projections on said tape adapted for
adjacent the plastic body, the plastic of the body
interengagement with’the plastic material in said
extended into permanent interlocking and bond
conduit.
i
ed relation to the material defining said recess 15
15.
The
combination
and arrangement of ele-and constituting a means of securement of the
ments as recited by claim 14, but further charac
. eraser to the pencil body, the body having a recess
terized by the addition of means providing an
at its end adjacent the eraser and the eraser be
endless
course or- passage for the ilexible tape
ing peripherally undercut to ?lt into the last said
recess and being formed to constitute a mortise 20 such that the tape ñrst enters then emerges
from a portion of said conduit, and valve means
type joint through which the manipulating body
in the zone of entrance of the tape to the conduit,
and the eraser are permanently bonded.
and adapted to prevent escape of the plastic
10. In a multiple extrusion apparatus for plas
material in said zone.
tic materials, an inner nozzle, an outer nozzle,
16. In plastic extrusion apparatus for forming
means forming coaxial passageways for the ma
an elongate article, an extrusion nozzle, means
terials extruded by the nozzles, means providing
for supplying the nozzle with a plastic material
distinct sources of supply of plastic materials
under pressure, a conduit beyond the nozzle, and
under pressure and serving to direct the mate
a combined cutoir gate and charging device for
rials toward and through the respective nozzles,
said eraser element into said passageway, respon
said passageway forming means including an ex
insert elements, said device being arranged for
movement substantially crosswise of the conduit,
tension of the inner nozzle, proxiding an elongate
and being provided with a plurality of pockets
thread-like passage therefrom extending a sub
adapted to serve, upon reciprocal movement of
stantial length beyond the inner nozzle in the
the gate and device, for periodic introduction of
direction of extrusion flow of material therefrom,
an insert element and substantially concurrent
the last said passage being of even diameter be
removal of a length of the material in the conduit
yond the inner nozzle, and the inner nozzle ex
which is comparable in volume to that of the
tension being an element of even external diam
insert.
eter, a reciprocal cutoif element adapted to work
17. In apparatus for forming an elongate arti
across and constitute a substantial length of the
passageway beyond the outer nozzle, and located 40 cle by plastic extrusion, an extrusion nozzle,
means for supplying the nozzle with a plastic
in the region of discharge of the passage-forming
material under pressure, a conduit beyond the
element extended from the inner nozzle.
nozzle, a combined cutoiî gate and charging de
11. In a device for forming and coating an
vice for insert elements, said device being ar
elongate plastic article, an extrusion nozzle,
means for supplying a plastic material under 45 ranged for movement transversely of the conduit,
pressure through said nozzle, a passage beyond
and adapted at times to interrupt the flow of
the nozzle, a conduit directed into said passage
plastic material therethrough, and at other times
and connected to a source of coating material,
to bring an insert element into the flow of mate
and a check valve arranged to control the supply
rial in said conduit, the gate and charging device
of coating material from said conduit to said 50 being characterized by a plurality of bores trans
passage.
versely therethrough, each of the bores being sub
12. In a device for forming an elongate article
stantially parallel to the axis of the conduit, and
by extrusion of a plastic, a nozzle, means for sup
spaced apart a distance corresponding substan
plying the nozzle with a plastic material under
tially
to the stroke of movement of the device
pressure, a conduit beyond the nozzle for receiv 55
across the conduit, and means for causing a re
ing the extruded material, a member movable
ciprocal movement of said gate and charging de
crosswise of the conduit and arranged periodi
vice in response to a deñnitely predetermined
cally to sever the material in said conduit, and
extent of now of the extruded material in said
a flow gauge for controlling the operation of the
severing member, said flow gauge including an 60 conduit.
endless ilexible member movable with the plastic
18. The herein described method of forming,
in said conduit and provided with a projection
as a subtantially continuous process, capped,
interengaging the plastic in the conduit whereby
cored, rod-like elements, each of predetermined
the flexible member is positively impelled by and
length, which method consists in simultaneously
extruding into a common forming passageway, a
coordinated with the movement of plastic in the
conduit, and means coacting with the endless 65 self-hardening plastic material to form the bodies
of the elements, and a plastic material to consti
flexible member, to control the actuation of the
cutoff member.
tute the cores of the elements, in the form oi a
material of self-hardening characteristics, and
13. The combination and arrangement of ele
ments as recited by claim 12, but further char 70 periodically, responsive to a predetermined length
of flow of the body-forming materials through
acterized in that the endless flexible member is
said passageway, introducing a cap element into
provided with driving means including an elec
said passageway, keying the cap element to the
tric motor, and a switch in circuit with said motor
body of plastic in the passageway while the body
arranged to be actuated at regular intervals, by
is in plastic state, and timing the insertion of said
the endless nexible member.
75 cap element into said passageway, responsively
15
to length of flow of material forming the bodies
of the elements, in said passageway.
19. In plastic extrusion apparatus for forming
an elongate article, an extrusion nozzle, means
for supplying the nozzle with a plastic material
under pressure, a conduit beyond the nozzle, and
a combined cutoff gate and charging device for
insert elements, said device being arranged for
movement in a direction to intersect the flow of
terials extruded by the nozzles, means providing
distinct sources of> supply of plastic materials
under pressure and serving to direct the mate
rials toward and through the respective nozzles,
said passageway-forming means including an ex
tension of the inner nozzle, providing an elongate
thread-like passage therefrom, extending a sub
stantial length beyond the inner nozzle in the
direction of extrusionñow of material therefrom,
material in the conduit, and being provided with l0 the last said passage being of uniform cross
sectionalY areas and shaping beyond theV inner
nozzle, and the inner Anozzle extension being an
element of uniform external shape. and cross
introduction of an insert element and substan
sectional areas, a cutoiî element adapted to work
tially concurrent removal of a length of the ma
terial in the conduit which is comparable in vol 15 across and constitute'a substantial length of the
passageway beyond the outer nozzle, and located
ume to that of the insert.
in the region of discharge of the passage-forming _
20. In a multiple extrusion apparatus for plas
element extended from the inner nozzle.
tic materials, an inner nozzle, an outer nozzle,
Y
THEODORE L. JOHNSON.
means forming coaxial passageways for the ma
a plurality of pockets adapted to serve, upon
movement ofthe gate and device, for periodic
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