U.S. patent number 3,597,714 [Application Number 05/028,861] was granted by the patent office on 1971-08-03 for magnetic rotary switch.
This patent grant is currently assigned to Aliprando Visconti Brebbia. Invention is credited to Federico Visconti Brebbia, Giorgio Visconti Brebbia.
United States Patent |
3,597,714 |
Visconti Brebbia , et
al. |
August 3, 1971 |
MAGNETIC ROTARY SWITCH
Abstract
Snap acting magnetic rotary switch having a plurality of
switches, each of which comprising two fixed contacts and one
movable contact, a permanent magnet being fast with the latter. The
switch also comprises two annularly shaped permanent magnets
adjacent each other and the magnets fast with said movable
contacts, the annular magnet outwardly positioned being fixed and
having as many pairs of poles as the switches and as many pairs of
poles being provided on the adjacent surface of the intermediate
annular magnet which is fast with a rotary shaft. On the surface of
the intermediate annular magnet facing the magnets fast with the
movable contacts three ring-shaped poles are provided, the sign of
which being alternately different; one of these poles is
interrupted at a location and the other two poles are deformed to
this location. Upon rotation of said shaft, the switch contacts are
snap opened or closed with a speed independent of the speed of
rotation of said shaft.
Inventors: |
Visconti Brebbia; Federico
(Milan, IT), Visconti Brebbia; Giorgio (Milan,
IT) |
Assignee: |
Aliprando Visconti Brebbia
(Milan, IT)
|
Family
ID: |
26327558 |
Appl.
No.: |
05/028,861 |
Filed: |
April 15, 1970 |
Foreign Application Priority Data
|
|
|
|
|
Feb 12, 1970 [IT] |
|
|
20522A/70 |
|
Current U.S.
Class: |
335/207 |
Current CPC
Class: |
H01H
5/02 (20130101); H01H 36/0073 (20130101); H01H
36/00 (20130101); H01H 2003/506 (20130101) |
Current International
Class: |
H01H
5/00 (20060101); H01H 36/00 (20060101); H01H
5/02 (20060101); H01h 005/02 (); H01h 019/60 () |
Field of
Search: |
;335/205,206,207
;200/67F |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Gilheany; Bernard A.
Assistant Examiner: Envall, Jr.; R. N.
Claims
What we claim is:
1. A rotary magnetic switch comprising a plurality of switches
circumferentially mounted on a rigid body and each having two fixed
contacts and a movable contact therebetween, a permanent magnet
fast with said movable contact and having a magnetized
sector-shaped surface thereof with at least two poles aligned with
said fixed contacts, a first annular permanent magnet fast with
said rigid body and having as many pairs of lateral magnetization
poles as the switches, and a shaft carrying a second rotary
permanent magnet annularly shaped and interposed between said first
permanent magnet and the permanent magnets fast with said movable
contacts, wherein on its surface opposite the adjacent surface of
the first permanent magnet said second permanent magnet has as many
pairs of lateral magnetization poles as the switches, the cross
section of the surface of the second permanent magnet opposite the
permanent magnets fast with said movable contacts is of a sector
shape conjugated to the sector shape of the permanent magnets fast
with the movable contacts and has at least three lateral
magnetization poles substantially in the form of three rings, the
intermediate ring of which is one pole and the two rings located
sidewise thereto are the other fractional pole, at least at a
location one of the sidewise located ring-shaped poles being
interrupted and the other ring-shaped poles being deformed to the
interruption location of said pole forming a recess accommodating a
lateral magnetization pole of opposite sign to that of the
ring-shaped pole adjacent thereto.
2. A rotary magnetic switch according to claim 1, wherein said
first and second annularly shaped permanent magnets comprise discs
parallel to one another wherein said pole pairs are radially
arranged and said ring-shaped poles are concentric and of diameters
different from one another.
3. A rotary magnetic switch according to claim 1, wherein said
first magnetic switch forms a stator portion for a stepping motor,
said second permanent magnet is a cylindrical tubular body forming
part of the rotor for said stepping motor and said ring-shaped
poles are coaxial and of diameters substantially identical to one
another.
Description
This invention relates to a magnetic rotary switch and more
particularly a snap acting magnetic rotary switch.
Rotary switches are known, comprising spring brushes rotating and
contacting further rigid brushes after one another, causing the
closure of contacts these brushes are part of; contact opening and
closing is carried out at the feeding speed of the rotating
brushes, this speed being always very low.
When desiring a fast opening and closing of the contacts,
microswitches are resorted to, which are generally provided with
so-called snap acting spring systems and operated by pushbuttons
carrying out contact opening and closing at a high speed; such
microswitches are also referred to as "snap" microswitches as the
opening and closing speed is always high and independent of the
feeding speed of the control pushbuttons. However, it is well known
that a series of microswitches arranged about a cam provided with a
shaft and mechanical snap action forms a complex, cumbersome and
expensive construction.
Magnetic switches, referred to as "proximity switches," are also
known and generally comprise a permanent magnet which, on
approaching two iron-magnetic contacts, cause the opening or
closing thereof; the contacts are usually arranged within a sealed
box and the magnetic control is through a diamagnetic diaphragm.
Known magnetic proximity switches are made as simple switches
having a single movable contact.
An object of the present invention is to provide a snap acting
magnetic rotary switch, fitted with a plurality of switches having
contacts which can be opened or closed by snap action, or a speed
independent of the speed of rotation for the switch.
Another object is to provide a snap acting magnetic rotary switch
which is of a simple structure and construction, inexpensive and
reduced size.
These and other objects are attained by a rotary magnetic switch
comprising a plurality of switches circumferentially mounted on a
rigid body and each having two fixed contacts and a movable contact
therebetween, a permanent magnet fast with said movable contact and
having a magnetized circular-shaped sector surface thereof with at
least two poles aligned with said fixed contacts, a first annular
permanent magnet fast with said rigid body and having as many pairs
of laterally magnetized poles as the switches, and a shaft carrying
a second rotary permanent magnet annularly shaped and interposed
between said first permanent magnet and the permanent magnets fast
with said movable contacts, this switch being characterized in that
on its surface opposite the adjacent surface of the first permanent
magnet said second permanent magnet has as many pole pairs of a
lateral magnetization as the switches, the cross section of the
surface of the second permanent magnet opposite the permanent
magnets fast with said movable contacts is of a circular sector
shape conjugated to the circular sector shape of the permanent
magnets fast with the movable contacts and has at least three
laterally magnetized poles substantially in the form of three
rings, the intermediate ring of which is one pole and the two rings
located sidewise thereto are the outer fractional pole, at least at
a location one of the sidewise located ring-shaped poles being
interrupted and the other ring-shaped poles being deformed to the
interruption location of said pole forming a loop, including
therein a laterally magnetized pole of opposite sign to that of the
ring-shaped pole adjacent thereto.
In order that the structure and features of the snap acting
magnetic rotary switch be more clearly understood, two embodiments
thereof will now be described as given by mere way of not limiting
example, reference being had to the accompanying drawings, in
which:
FIG. is an axial sectional view showing a first embodiment of the
snap acting magnetic rotary switch;
FIG. 2 is a plan view showing the switch carrying portion of the
switch in FIG. 1;
FIGS. 3, 4 and 5 are a cross-sectional view, and respectively views
from either side of an annular permanent magnet forming part of the
switch;
FIG. 6 is an axial sectional view showing a second embodiment of
the snap acting magnetic rotary switch; and
FIGS. 7, 8 and 9 are, respectively, a cross-sectional view, a side
view and a front view of a permanent magnet in the form of a
cylindrical tubular body forming part of the switch in FIG. 6.
Firstly, reference is had to FIGS. 1--5, wherein a first embodiment
of the snap acting magnetic rotary switch is shown. This switch has
a rigid body 1 (FIGS. 1 and 2) carrying ten switches
circumferentially arranged and each comprising an inner fixed
contact 2, an outer fixed contact 3 and a contact 4 which is
movable between contacts 2 and 3: in the embodiment shown in FIG.
1, the movable contact 4 is rockably mounted on a pin 5 and
therewith a permanent magnet 6 is fast, the free surface of which
is sector-shaped with its center on the axis of pin 5, the magnet 6
being two-pole magnetized, which poles are aligned with said fixed
contacts 2 and 3 and all having the pole of one sign adjacent
contact 2 and the pole of opposite sign adjacent contact 3.
In the switch a rigid body 7 (FIG. 1) is fast with the rigid body
1, having secured thereto a first permanent magnet 8 in the form of
an annular disc, and more particularly a washer, the surface of
which facing the switches has ten pairs of laterally magnetized
poles, radially extending on the surface of magnet 8 in a
completely similar manner as shown in FIG. 4 and as described
below.
A rotary shaft 9 is mounted on body 7 and freely rotatable about
its axis, a second permanent magnet 11 shaped as an annular disc,
or more particularly as a washer, being fast with end of this
shaft. FIGS. 3, 4 and 5 show said magnet 11 in cross-sectional view
and plan views from either side. On its surface opposite the
adjacent surface of magnet 8, this magnet 11 has ten pairs of
laterally magnetized poles radially extending, as clearly shown in
FIG. 4. As above outlined, these poles of magnet 11 are completely
similar to those on magnet 8.
The surface of magnet 11 opposite magnets 6 fast with the movable
contacts 4 is of a sector-shaped cross section conjugated to the
sector shape of magnets 6, as clearly shown in FIG. 3 and
particularly FIG. 1; three lateral magnetization poles are formed
on said surface of magnet 11, substantially as three concentric
rings of different diameters from one another (FIG. 5), the
intermediate ring being one pole and the two rings sidewise located
thereto being the other fractional pole. Still as shown in FIG. 5,
at the location of magnet 11 designated by A, that pole of said
ring-shaped poles which is sidewise located and of a smaller
diameter than the other ring poles, is interrupted, whereas the
other two ring-shaped poles are deformed to the interruption
location of the other pole, providing a loop receiving a lateral
magnetization pole of opposite sign to that of the ring-shaped pole
adjacent thereto, as clearly shown in FIG. 5, at the location
designated by A.
The radially arranged poles on the opposite surfaces of magnets 8
and 11 are effective to firmly hold at exactly determined steady
position shaft 9 with magnet 11 relative to body 7 with magnet 8
relative to magnets 6. When rotated, shaft 9 will stop at one of
ten different angular positions where location A of magnet 11 is
positioned at one of said magnets 6.
As shown in the drawings, since magnets 6 of the movable contacts 4
are of opposite polarities to those of the ring-shaped poles on the
adjacent surface of magnet 11, it ensues that magnets 6, except for
that magnet located at location A of magnet 11, are attracted from
one side, or are urged towards contacts 2, against which contacts 4
bear. Only that magnet 6, which is positioned at location A of
magnet 11, is urged in a direction opposite that of the other
magnets 6, or is outwardly urged, so that its movable contact 4
rests on contact 3 adjacent thereto.
During rotation of shaft 9, all but one of the contacts 4 fast with
magnets 6 rest on contacts 2: as location A of the ring poles for
magnet 11 approaches the subsequent contacts 4 resting on the
subsequent contacts 2, these contacts 4 are increasingly forced
onto the associated contacts 2 until, when the maximum pressure has
been attained, the magnetic balance is inverted and magnets 6 with
their contacts 4 are strongly urged to the other side, that is
against the adjacent contacts 3, thus causing the contact to shift
rapidly. It should be noted that the contact switching speed is
independent of the speed of rotation of shaft 9 and magnet fast
therewith.
Reference will be had now to FIGS. 6--9 relating to an embodiment
of the rotary magnetic switch different from that above
described.
The switch of FIG. 6 comprises a rigid body 12 carrying ten
switches, each of which comprising an inner fixed contact 13, an
outer fixed contact 14 and an intermediate movable contact 15
carrying a permanent magnet 16, with a structure completely similar
to that as described in connection with FIG. 1.
The switch also comprises a permanent magnet 17, shaped as a
cylindrical tubular body, as clearly shown in FIGS. 7, 8 and 9. The
magnet 17, fast with two discs 18 and 19, respectively, rotating on
a fixed shaft 20, is part of the rotor for a stepping motor
provided with coils 21 and having a permanent magnet 22 forming a
stator portion of the stepping motor. On its surface opposite the
magnet 17, said magnet 22 has ten pairs of lateral magnetization
poles and as many pairs of lateral magnetization poles are provided
on the cylindrical inner surface of magnet 17, as shown in FIG.
7.
On its outer surface said magnet 17 has a slot of a sector-shaped
cross section conjugated to the sector shape of magnets 16, as
shown particularly in FIG. 6 and FIG. 8. At said slot, magnet 17
has three pairs of lateral magnetization poles, particularly shown
in lateral 8, substantially in the form of three rings coaxial one
another and of diameters substantially identical to one another;
wherein the intermediate ring is one pole and two rings located
sidewise hereto are the other fractional pole. Similarly as stated
in connection with the above described construction for the switch,
at location B one of the sidewise located ring-shaped poles is
interrupted and the other two ring-shaped poles are deformed to the
interruption location of the other pole, forming a loop or recess
accommodating a lateral magnetization pole of opposite sign to that
of the ring-shaped pole adjacent thereto. The operation of the
switch is completely similar to that for the switch of FIGS. 1--5,
since for each step feeding of the stepping motor, the location B
of magnet 17 is subsequently positioned on a distinct magnet 16
which is snap shifted from a position where it rests on a contact
13 to a position where it rests on an adjacent contact 14. Still
here the shift speed for the movable contact 15 from one fixed
contact to the other fixed contact is independent of the speed of
rotation of rotor 17, that is the speed of rotation of the stepping
motor. From the foregoing it will be readily seen that the
construction of the rotary magnetic switch is simple, the operation
of the switches is carried out merely through the action of a
magnetic field not causing any mechanical wears and avoiding,
therefore, any risk of wear breakages, and the capability of
providing a very rapid operation of the individual switches which
are firmly retained at a steady position by the magnetic field of
the rotary magnet adjacent thereto.
* * * * *