U.S. patent number 3,570,353 [Application Number 04/822,249] was granted by the patent office on 1971-03-16 for electromagnetic cutting device with change-over switch.
This patent grant is currently assigned to Heberlein & Co. AG. Invention is credited to Kurt Hess.
United States Patent |
3,570,353 |
Hess |
March 16, 1971 |
ELECTROMAGNETIC CUTTING DEVICE WITH CHANGE-OVER SWITCH
Abstract
Cutting device for thread, rope, wire and the like actuated
electromagnetically with means for holding an end of the material
to be cut during and after cutting, the cutting movement being
automatically repeated if the material is not cut through
completely on the previous movement.
Inventors: |
Hess; Kurt (Canton, Luzern,
CH) |
Assignee: |
Heberlein & Co. AG
(Wattwil, CH)
|
Family
ID: |
4319466 |
Appl.
No.: |
04/822,249 |
Filed: |
May 6, 1969 |
Foreign Application Priority Data
|
|
|
|
|
May 13, 1968 [CH] |
|
|
7071/68 |
|
Current U.S.
Class: |
83/576; 83/577;
83/580 |
Current CPC
Class: |
B65H
54/71 (20130101); B26D 5/08 (20130101); B65H
63/088 (20130101); B26D 5/086 (20130101); B21F
11/00 (20130101); Y10T 83/8772 (20150401); F16B
2012/446 (20130101); B65H 2701/31 (20130101); Y10T
83/8766 (20150401); Y10T 83/8768 (20150401) |
Current International
Class: |
B26D
5/08 (20060101); B21F 11/00 (20060101); B65H
63/08 (20060101); B65H 63/00 (20060101); B26d
001/09 () |
Field of
Search: |
;83/575,576,577,580 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Lawson; William S.
Claims
I claim:
1. Cutting apparatus for thread, rope and wirelike material with a
cutter actuated by the armature of an electromagnet, characterized
by a cutter having a free extremity, a coupling member rigidly
connected to said armature, means for mounting said cutter on said
coupling member for horizontal sliding movement and for vertical
swiveling movement, a fixed knife cooperating with said cutter to
cut material when said cutter is advanced, and a traction spring
attached to the cutter for exerting pressure between said cutter
and the rigid knife, as well as a retracting force acting on the
cutter and the armature.
2. Cutting apparatus for thread, rope and wirelike material with a
cutter actuated by the armature of an electromagnet, characterized
by a cutter having a free extremity, a coupling member rigidly
connected to said armature, means for mounting said cutter on said
coupling member for sliding movement in one direction and for
swiveling movement, a fixed knife cooperating with said cutter to
cut material when said cutter is advanced, and a traction spring
attached to the cutter for exerting pressure between said cutter
and the rigid knife, as well as a retracting force acting on the
cutter and the armature, a material pinching means comprising a
member rigidly connected with the cutter for moving therewith, and
a pad fixed opposite the end of said member and against which pad
the member presses the cut material after cutting has been
effected.
3. Cutting apparatus for thread, rope and wirelike material with a
cutter actuated by the armature of an electromagnet, characterized
by a cutter having a free extremity, a coupling member rigidly
connected to said armature, means for mounting said cutter on said
coupling member for sliding movement in one direction and for
swiveling movement, a fixed knife cooperating with said cutter to
cut material when said cutter is advanced, and a traction spring
attached to the cutter for exerting pressure between said cutter
and the rigid knife, as well as a retracting force acting on the
cutter and the armature, contact means arranged at one end of the
armature and comprising a conductive member and an insulating
member for actuating a switch member to effect a series connection
of the induction coil of the electromagnet with a resistance before
the armature reaches the full limit of its protrative
excursion.
4. Cutting apparatus according to claim 3, characterized in that
the induction coil, the armature and the traction spring are so
selected that, when the coil is connected in series with said
resistance, a current flows in the coil which, when the material to
be cut has been separated completely, is just sufficient to hold
fast the armature and the cutter in close contact with the magnet
core whereas, if the material has not been cut through completely,
the current is not sufficient because of the airgap existing due to
the thickness of the uncut material between the armature and the
core, wherefore the armature and the cutter are retracted into
their original position by the spring and a repetition of the
cutting movement occurs.
5. Cutting apparatus according to claim 1, characterized by a
ring-shaped knife opened to one side which is arranged to cooperate
with the moveable cutter.
Description
The present invention relates to a cutting device for thread, rope
or wire and the like, and includes a cutter which is actuated by
the armature of an electromagnet or solenoid.
In order to effect reliable and precise cutting of textile threads,
ropes or wires, for example, apparatuses are known in which two
cutting edges which are moved towards each other in the manner of
scissors, and in which the material remaining after the cut, is
caught or pinched fast by a special device separate from the
cutting device.
In a further known cutting apparatus, a bank of knives rigidly
fixed on the armature of an electromagnet and which has a passage
for the material to be cut arranged within the cutter, is lead
horizontally and with a traction movement against a cutting edge
which is horizontally stationary, together with the passing
material to be cut. The cutter is thus vertically pressed against
the surface of the knife bank by a pressure spring acting from
above so that, as the length of the path of movement of the knife
bank increases until it meets with the cutting edge of the cutter,
the pressure of the cutter against the knife bank also increases so
that the pressure is at its maximum when cutting is effected.
The disadvantage of this apparatus consists in that, under certain
circumstances, the knife bank may draw the material to be cut out
of its normal running path so that it forms an angle with the
cutting and knife edges, whereby, instead of cutting the material,
it may pinch the latter between the cutter and knife edges.
Furthermore, because of defects such as knots, differences in
diameter and so on, which occur in the material to be cut, it may
not be possible to advance the same uniformly between the knife
bank and the cutter edge because the cutter edge is lifted from the
knife, and this may also lead to pinching of the material to be
cut.
In another known apparatus, the separation of the threads is
effected by the armature of a solenoid by centrally attracting the
armature which can be swiveled about one end thereof, whereby a
cutter fixed on the other end of the armature strikes a conical
anvil with a cutting edge, a thread being led over the anvil by
means of a thread leading groove. The cutter is situated on one arm
of a U-shaped device on the other arm of which is provided a thread
pinching device, which, acting simultaneously with the cutter,
fixes the thread on a further anvil. After termination of the
cutting step, the cutter is lifted away from the anvil together
with the thread pincher by a retraction spring arranged above the
swivel center of the armature.
This apparatus also presents the disadvantage that, by hammerlike
advancing of the cutter as well as by the cutting faces gliding
past each other in an oblique plane, respectively, pinching of the
material to be cut may also occur within a wedge-shaped groove of
the anvil. Moreover, with continuously moving armatures, there is
the danger of armature vibration which is caused by the traction
spring as well as by saturation of the magnetic field, being
transferred to the cutter. Furthermore, in continuous armature
movement, much of the cutting force is absorbed by the preceding
friction between cutter and knife bank, so that the remaining
cutting force of the armature is reduced for the actual cutting
operation.
I have conceived by my present invention, a cutting device which
eliminates the foregoing difficulties and disadvantages by means of
a cutting device which is actuated electromagnetically, the cutting
movement being automatically repeated, should the material not have
been cut through completely.
Accordingly, I provide a cutting device for thread, rope, wire or
the like, with a cutter actuatable by the armature of an
electromagnet, comprising: a slidable and swivellable cutter which,
at a free extremity, cooperates with a coupling part rigidly
connected with the armature, and which cooperates at its other end
with a fixed knife. I further provide a retraction spring for
applying a force between the sliding cutter and the stationary
knife, as well as for applying a retractive force on the knife and
on the armature.
As a further feature of my invention, I provide means for pinching
the material to be cut just prior to the cutting and for retaining
an end of the material in that condition as long as desired after
cutting occurs. Such means may include a member which shifts with
the cutter but which precedes it during the protraction excursion;
and a pad against which such member presses the material to be cut
just prior to the actual cutting.
Another feature of the invention resides in the provision of a
resistance which is normally bridged by the solenoid induction coil
circuit; but which can be placed in series with the coil by a
switch in the bridging circuit. The various parts are so arranged
that bridging is interrupted just prior to completion of the
protraction excursion wherefor pinching and holding of the material
is effected only by a holding current. However, if the material is
not cut on the first protraction, its thickness causes an airgap
between the coil and core of the solenoid, and this gap, together
with the low holding current and the retraction spring, return the
cutter to its starting position from which it again strikes at the
material and continues to do so until cutting is achieved after
which it remains protracted to hold the material end.
Further specific features and advantages of the invention will be
hereinafter more fully set forth with reference to the annexed
drawings, showing a presently preferred embodiment of the invention
and certain modifications thereof, in which:
FIG. 1 is a side elevational view of the apparatus of the present
invention in its normal at rest position;
FIG. 2 is a plan view of a part of the cutting device in normal
position;
FIG. 3 is a view similar to that of FIG. 1, but showing the
apparatus in cutting position;
FIG. 4 is a plan view similar to that of FIG. 2, but showing the
cutting device in cutting position; and
FIG. 5 is a circuit diagram of the electrical system.
The cutting device shown in FIGS. 1 and 2 consists of a housing 1
in which a pot magnet 2 and tubular coil 3 are arranged. An
armature 4 with a conical attraction surface 5 in which a pin 6 is
fixed by means of screws is positioned for axial movement in the
coil recess. The enlarged end 7 of the pin 6 has a central opening
8 for vertically swivellable arrangement therein of a cutter 9, and
of a pinching member 10 which is rigidly fixed on the upper face of
the cutter 9. The cutter 9 is drawn against a knife 14 by a
retraction spring 11 which, by one of its extremities, is attached
to a hook 12 provided on the housing 1. During advancing of the
armature 4 and, therefore, of the cutter 9 when the coil is
energized, the pressure against the knife bank 13 and the knife 14
provided thereon is increased as the knife comes forward due to the
effect of the spring 11. On one side, the knife 14 is provided with
an opening 15 for passage of the material 16 to be cut. During the
cutting procedure, the member 10 for pinching the material to be
cut, and which slightly protrudes over the cutting edge of the
cutter 9, presses the material 16 to be cut against an elastic pad
17 which is fixed on the rear wall 19 of the housing, and there
maintains the material 16 to be cut in position.
After cutting has been effected, the cutter 9, together with the
member 10, is maintained in the cutting position by the armature 4
and the pin 6 as shown in FIGS. 3 and 4, this condition being
maintained as long as the current circuit is closed.
After reinserting the material 16, the cutter 9 and member 10 may
be returned to normal position by interrupting the current
circuit.
The protractive movement of the armature 4 together with the pin 6
and the cutter 9 together with the material pinching member 10 is
effected as follows:
On the free end of armature 4, a metal ring 26 is provided with an
insulating ring 27 lining the inner surface thereof. In its normal
position, the contact point of a switching contact 25 is in contact
with the metal ring 26, so that the resistance 24 in the current
supply line for the coil 3 is coil However, in a certain position
of the armature 4 within the coil 3, contact point of the switch
contact 25 comes into contact with the insulating ring 27, wherefor
the bridging of the resistance 24 is interrupted, and the coil 3 is
connected in series with the resistance 24. In this circumstance,
only a relatively small holding current flows through the coil 3,
and the armature 4 is, therefore, during the last portion of its
protractive excursion, moved only by the holding current and its
mass acceleration.
The advantage of the above lies in the fact that the armature 4,
with the cutter 9 and the member 10, is maintained in protracted
position by only a very slight holding current, while the cut
material is pinched between the member 10 and pad 17 until the
current circuit is completely interrupted by the switch 28 (FIG.
5).
When a very thick or very hard material is to be cut, the holding
current is not sufficient to hold the armature 4 with the cutter 9
and the member 10 in the cutting position of FIGS. 3 and 4 because
of the remaining airgap between the armature 4 and core cap 20.
Accordingly, the armature 4 is retracted into its original position
(FIGS. 1 and 2) by the spring 11, and the resistance 24 connected
in series with the coil 3 is again bridged by the switch contact
25, wherefor full current flows again in coil 3, whereby the
cutting procedure is automatically repeated until the material is
completely cut through.
From the foregoing description, it will be seen that an essential
advantage of the cutting device of the present invention consists
in that the cut may be effected in all positions of the thread;
that, by a series circuit of the induction coil with a resistance,
an undesirable heating of the coil is prevented; and that, when a
thick or hard material is incompletely cut, the cutting is
automatically repeated until the material is completely cut
through.
I believe that the construction and operation of my contribution
will now be fully understood, and that its advantages will be
appreciated by those persons skilled in the art.
* * * * *