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Патент USA US2404500

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July 23, 1945.
2 Sheets-Sheetl
Filed May 11, 1944
' " Ju-ly 23, 1946.
Filed May 11, 1944
2 Sheets-Shéet 2
I ‘!
“BY .'
Patented July 23, 1946
f l-"umrso STATES PATENT-lorries“)
2,404,500 '
Conrad Jobst, Toledo, on... assignor to The
Toledo Automatic Brush. Machine Company,
. Toledo, Ohio, a corporation of Ohio
Application May 11, 1944, ‘Serial No. 535,165
5 Claims. (01. 1034-47)
ward movement of the handle being trimmed.
The invention relates‘ to trimming mechanisms
The‘ cutting edgesrof the cutter are formed by
grinding the member B in oppositely inclined
planes oblique to the plane of reciprocation and
and has more particular reference to a construc
‘ tion adapted for the speci?c. use in the trimming
off of sprue stubs from molded plastic articles.
The device is, however, useful for other purposes.
It is the object of the invention to obtain a
construction which will quickly remove the pro
jecting stub and will impart to the article a
smooth ?nished surface free from cracks or other
defects and in continuation of the molded surface. 10
' It is a further object to obtain a construction
which is adapted for the trimming of fashioned
articles other than those formed of molded plas
tics. With these objects in view, the invention
consists in the construction, as hereinafter set 15
In the drawings:
Fig. l is a front elevation of my improved trimmer;
Fig. 2 is a side elevation partly in section;
on the opposite side from the contour F. This
will form a substantially oval line of intersection
G with’ the contour surface having substantially
V-shaped opposite end-portions G’, G2 and leavi
ing therebetween an aperture through which the
stub may be fed.
For convenience in grinding
the cutter and for permitting resharpening of the
same, thecutter B is preferably formed‘‘ in two
sections B’ and B2 which are separately adjust
ably mounted on the member A by bolts H, H"
passing. through slots I, I’ therein. This also
permits of relatively adjusting said section so as
to have an exact dimension between the apices of
the portions G’. G1.
The reciprocatory member A is mounted on a .
20 ‘suitable frame J having guideways K and K’.
' Fig. 3 is a horizontal section‘ substantially on
line 3-—3, Fig. 2;
Movement is imparted to the member A by any
suitable mechanism such asa crank L connected
by a rod M to a pin N projecting rearward from
said member; The throw of the crank L is such
‘ tion of Fig. 3;
25 as to impart to the member A an amplitude of
Fig. 5 is a section on line 5-5, Fig. 4;
movement‘which is slightly greater than the di
Fig. 6 is a diagram illustrating the operation
mension between the apicesG’, G2 of each cutter
of the trimmer; and
fora purpose hereinafter described».1 'The- frame
Fig.7 is a section similar to Fig. 4 illustratin
J has also mounted on the front‘ face thereof a
a modi?ed construction.
Articles formed of synthetic plastic materials 30 memberO in ‘which are formed apertures P, P'
in alignment respectively with the center line of
are usually molded in gates in which the individ
each of the cutters B. Each of these apertures
ual articles are connected by sprues. When these
is, ‘also‘in alignment'with a point in said ‘center
articles are detached, the sprue stubs must be
line whichis’ubstantially registers withthe apices
removed and, unless this operation is carefully
G'QG2 when at opposite ends of the reciprocatory
performed, it will leave a blemish in the ?nished
movement of‘ the ‘cutter. These apertures permit
surface. Thisis for the reason that the stresses
incident tothe cutting off of the stub may form ' of feeding-the=work' therethrough into engage
‘ment with the cutters and also form positioning
a crack or a breaking out of material below the
means therefor. As shown, the walls Q of the
?nished surface. Consequently," this operation
apertures P and P’ are ?ared in anloutward di
is usually manually performed requiring great
rection so as to permit of slightly rocking the
care on the part of the workman and adding to
work during engagement thereof with the cutter.
the cost of production.
Fig. 4 is an enlarged section similar to a por
My improvement is designed to greatly expedite
the trimming operation and to avoid any marring
of the ?nished surface, the construction being as 45
follows. A
is mounted
cutters has
ing to the
is a reciprocatory member on which
one or more cutters B. Each of these
a cross sectional contour correspond
?nished surface of the article to be
trimmed. As speci?cally illustrated in Figs. 4
and 5, this article is a molded plastic toothbrush
handle C having a rounded end D with the sprue
stub E projecting therefrom. The cross sectional
contour F of the‘ cutter B corresponds to the
When the machine is in operation, a very rapid
reciprocatory movement is imparted to the mem
her A by the crank L and rod M, the crank be
ing driven by any suitable means (notshown),
such as an electric motor. The ‘operator may
then feed the work such as a toothbrush han
dle C through the guide bringing the sprue E
in contact with the contour F of the cutter B.‘
As the sprue is of a width less than that of the
aperture formed by the~cutting edge G, it can
rounded end D, Fig. 4, thereby limiting the in 55 pass through said aperture but, on account of
the rapidity of reciprocatory movement, will be
_ 2; A trimming mechanism comprising a re-‘
inserted only a slight amount before engagement
with said cutting edge. Consequently, the ma
terial of the stub will be successively removed
ciprocatory member, a pair of aligned cutters
mounted on said member having opposed cut
ting edges spaced from each other by a dimen
in thin shavings until further inward movement 5 sion ‘slightly less than the amplitude of recipro-'
of the member C is prevented by contact of the a catory movement, and means for holding the
surface D with the surface F. At this point the
work to be trimmed in operative relation to said
shaved surface will form a continuation of the .
cutter at a pointsubstantiallyfin registration re
spectively with‘ said opposed edges‘? at opposite
An essential feature in the operation above N) ends of the reciprocatory movement thereof.
described is that the cutting edge does not travel_
3. A trimming mechanism comprising a re
completely across the stub or projection in either
ciprocatory member, a pair of aligned cutters
of the reciprocatory movements of “the ' cutter;
mounted‘v on said member'having opposed cut
Preferably, the movementi'sixreversed when .the/
of the stub and, therefore, a substantial~amount-- ~
ztin'gzedg'es ?aringxfrom spaced apices towards a
center 'I'therebetween, the amplitude of recipro
catory movementbeing but slightly greater than
of material remains in said stub as a backing for
the portion shaved. As a consequence, there is
lfor'holding the work to be trimmed in operative
cutting edge has only slightly passedethe :center.
‘thedimension between said apices, and means
no danger of either cracking or breaking :out' » relation to said cutter at a point substantially in
material from beneathlthe line of cut as might 20 registration respectively with said opposed edges
.be....the :case. if the cutting edge were to com-'
atpppositeends of thereciprocatory movement
~pletely traverse the areaofthe projecting stub.
it willalsozbe observed ‘that the direction of
4..A_ trimming mechanism comprising :a re
movement ..of . ‘the . cutting edge ,is substantially
ciprocatory gmember, a pair of aligned cutters
radially inward from all‘ ‘portions thereof, ‘this
; mounted thereon having an extended surface of
being due vtoits .oval or reverseV-shaped form.
,Theiresult will be-theforming of a smooth ?n
a crosssectional contour corresponding to the
desired contour in the article to .be trimmed, said
surface being apertured to form ‘a ‘surrounding
.ishedsurfacerin continuation of the molded sur-i
faoe?ofthe article. ,Furthermore, as the guide
. ,3or..§;positioning_
work, the?-nished
will also
of rocking
the moldedsurface in a transverse plane. By
having a;p_air of adjacent trimmers simultaneous-»
cutting edge havingapicesat opposite ends there
of spaced from each other ‘by a dimension sub
stantially equal-to the amplitude of reciprocatory
movement, and means .for holding the work to
be trimmed in operative relation tov said cutter
ly__ operating,_ the attendant can hold a piece‘ of
workgineaoh handand simultaneously perform
both. trimming operation-a
. . ..
at a point substantiallyrini registration with said
opposed edges at oppositellends of the recipro- .1
catory movement thereof.
1 The modi?ed construction‘ shown
-7 ;is
substantially the same as that shown" in Fig. 4
with theexception that the contour of the han—_
5. A trimmer mechanism comprising a'recipro
catory member, apair of cutters mounted there
on, each having an extended surface of a cross
,dle‘ is a di?gerentgcurve. Thus, instead of the 40 sectional contour corresponding‘ to the desired
singlezarcuate curve shown in Fig. lihthere are
contour in the articletq be trimmed, each of said
"two, smaller curvesD' on opposite sides of the
end of the handle and a jre-g-entrant curve’ 1D2
cutters being cut away in an oblique plane from
the side opposite’ to-said extended surface to in
tersect the latter and form an aperture therein
therebetween. 'Ijhe cutter is formedto a simi-,.
lar; contour and the operation is substantially :45 with a surrounding cutting edge ‘having an apex
the same‘as‘with the other construction. 7 A
at one end thereof, said ‘cutters ‘beingv relatively
gill-hat :I claim as my invention is;
adjustably mounted on said reciprocatory mem
{method of trimming/0ft projections from ‘
her to space the apices by a dimension slightly
a- fa shionedf surface-of
less than the amplitude of reciprocatory 'move
anariicle which ‘consists -
in, reciprocating _'a pair of aligned cutters hav
ing; {opposed spaced : cutting __.edges,__ giving "said
reciprocations an amplitude of reciprocatory
movement, being substantially ‘equal. to. the ‘di
ment and with the‘ cuttingedges opposed to‘each
I mensionbetween said opposed-edges,~and in feed
ing, the articletoward said cutter. at a point sub
stantially -in registrationlwith the Opposite’ lim-k‘
‘ 'itssof movement of said cutting edges.
othenland means V.-for holding the work to be
trimmed in operative relationto said‘ cutter at
a point“ substantially in registration with said
apices respectively at opposite ends of the 're--,
h v
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