U.S. patent number 3,830,099 [Application Number 05/330,680] was granted by the patent office on 1974-08-20 for electromagnetic vibrator having means for changing direction of vibrations.
This patent grant is currently assigned to International Mechanical Vibration Laboratory, Inc.. Invention is credited to Akihisa Ichikawa.
United States Patent |
3,830,099 |
Ichikawa |
August 20, 1974 |
ELECTROMAGNETIC VIBRATOR HAVING MEANS FOR CHANGING DIRECTION OF
VIBRATIONS
Abstract
An electromagnetic vibrator having spaced apart magnets mounted
on an axis, and a drive coil interposed between the magnets, the
drive coil being vibrated by energization thereof by an A-C
current. The magnets are rotatable about an axis so as to change
the direction of vibration of the drive coil. A set of rollers
engaging respective generally L-shaped guide plates, the guide
plates being coupled to the coil via a plate member, is provided so
as to additionally change the direction of vibration of the drive
coil. To change the direction of vibration, the rollers are
selectively engageable with perpendicular surfaces of the generally
L-shaped guide plates.
Inventors: |
Ichikawa; Akihisa (Itami,
JA) |
Assignee: |
International Mechanical Vibration
Laboratory, Inc. (Osaka, JA)
|
Family
ID: |
12157088 |
Appl.
No.: |
05/330,680 |
Filed: |
February 8, 1973 |
Foreign Application Priority Data
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|
|
|
|
Mar 2, 1972 [JA] |
|
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47-25121 |
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Current U.S.
Class: |
73/668; 366/127;
310/28 |
Current CPC
Class: |
H02K
33/18 (20130101); G01M 7/04 (20130101) |
Current International
Class: |
G01M
7/04 (20060101); G01M 7/00 (20060101); H02K
33/18 (20060101); H04r 009/04 () |
Field of
Search: |
;259/1R,DIG.41
;73/67.4,71.6 ;310/DIG.1,27,28,30 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Roberts; Edward L.
Assistant Examiner: Cantor; Alan
Attorney, Agent or Firm: Flynn & Frishauf
Claims
I claim:
1. An electromagnetic vibrator providing a vibrating force through
energization of a drive coil disposed in a magnetic circuit with
A-C current, said vibrator comprising:
two magnets symmetrically arranged on the same axis and spaced from
each other along said axis such that a pole pair of one magnet
respectively faces opposite polarity poles of the other magnet;
means for rotating said magnets about said axis; and
a drive coil interposed between said two magnets and traversing a
magnetic path between said magnets and being vibrated upon
energization thereof by said A-C current, said drive coil being
wound into a ring-like form along the direction of rotation of said
magnets.
2. The electromagnetic vibrator according to claim 1 further
comprising a stationary frame accommodating said magnets and said
drive coil; a vibrating table supported on said stationary frame so
as to be capable of vibration with respect to said stationary
frame; and a shaft constituting said axis extending through the
opening of said ring-like drive coil and rotatably mounted at
opposite ends in said stationary frame, said magnets being each
symmetrically secured to said shaft, and said drive coil being
carried by said vibrating table.
3. The electromagnetic vibrator according to claim 2 including air
spring means supporting said vibrating table on said stationary
frame.
4. The electromagnetic vibrator according to claim 2 further
including a plate member interposed between said two magnets and
secured at one end to said vibrating table, said plate member being
formed with a central opening or aperture of a diameter greater
than the diameter of said shaft, said shaft extending through said
opening, said drive coil being disposed at at least one side of
said plate member and secured thereto.
5. The electromagnetic vibrator according to claim 4 wherein said
drive coil is comprised of two coils, each of which is secured to
opposite sides of said plate member.
6. The electromagnetic vibrator according to claim 4 further
comprising generally L-shaped guide plates coupled to said plate
member adjacent the corners thereof, and guide rollers extending in
contact with respective L-shaped guide plates; means for shifting
the positions of said guide rollers relative to said respective
L-shaped guide plates and relative to said stationary frame, the
direction of vibration of said vibrating table being determined by
the positions of said guide rollers relative to said respective
L-shaped guide plates.
7. The electromagnetic vibrator according to claim 6 wherein said
guide rollers engage a given surface of said respective L-shaped
guide plates for a given direction of vibration of said vibrating
table, and said rollers engage a different surface, which is
perpendicular to said given surface, of said L-shaped guide plates
for vibration of said vibrating table in a second direction
different from said given direction.
8. The electromagnetic vibrator according to claim 7 wherein said
given and second directions are substantially perpendicular to each
other.
9. The electromagnetic vibrator according to claim 6 including air
spring means supporting said vibrating table on said stationary
frame.
Description
This invention relates to vibrators producing mechanical
vibrations, and more particularly, to electromagnetic vibrators
capable of providing vibrational forces in different
directions.
Vertical and horizontal vibration tests should usually be conducted
on articles, or parts thereof, which will be subject to strong
vibrations in use or during transportation in order to check their
durability in vibratory environments, whether or not their
performance changes in such environments and other effects of
vibrators thereon.
Prior art electromagnetic vibrators for carrying out the above
vibration tests are capable of producing vibrations of the test
body only in one direction. Therefore, vertical and horizontal
vibration tests generally had to be done by separately using a
vertical vibrator and a horizontal vibrator. In the prior art, when
using the same vibrator for both vertical and horizontal vibration
tests, it was required to provide a vertical vibrating table and a
horizontal vibrating table which could be selectively coupled to
the vibrator. In either of the above cases, it is necessary to
separately mount the test article on the vertical and horizontal
vibrating tables for the individual tests. Further, a considerably
large space is required for the testing equipment, since more than
one vibrator or vibrating table is required.
It is therefore an object of the present invention to overcome the
above drawbacks of the prior art vibrator arrangements by providing
an electromagnetic vibrator, which is capable of selectively
vibrating the test body both in the vertical and horizontal
directions without requiring separate vibrator devices and/or
vibrating tables.
SUMMARY OF THE INVENTION
The invention comprises an electromagnetic vibrator, which includes
two magnets symmetrically arranged with respect to the same axis
and spaced from each other along the axis such that a pole of one
polarity of one magnet faces the opposite polarity pole of the
other magnet, the magnets being capable of rotation about the axis.
A coil is interposed between the two magnets and traverses the
magnetic path defined between the two magnets, the coil being wound
into a ring-like form along the direction of rotation of the
magnets. The electromagnetic vibrator according to the invention,
while it utilizes the same basic principles as does the usual
electromagnetic vibrator, is so constructed as to permit varying
the direction of the magnetic path defined by the magnets by
rotating them, to thereby obtain vibration in any desired
direction.
In accordance with the invention, since it is possible to obtain
vibration in any desired direction by rotating the magnets to a
desired position, there is no need for separately mounting the test
body on a plurality of vibrating tables for the individual
vibration tests. Vibration tests for vibrations in different
directions can be done on the same vibrating table. Also, since no
more than one vibrator is required, the space or area required for
the vibration test apparatus can be reduced.
BRIEF DESCRIPTION OF THE DRAWING
FIGS. 1A and 1B show a conventional two directional vibrator, FIG.
1A being a section along line 1A--1A in FIG. 1B, and FIG. 1B being
a side elevational view;
FIGS. 2A and 2B show an electromagnetic vibrator according to the
present invention for use as a vertical vibrator, FIG. 2A being a
section taken along line 2A--2A in FIG. 2B, and FIG. 2B being a
section taken along line 2B--2B in FIG. 2A;
FIG. 3 is a view similar to FIG. 2A but showing the same vibrator
for use as a horizontal vibrator;
FIG. 4 is a front elevational enlarged view illustrating the roller
mechanism of the present invention; and
FIG. 5 is a bottom plan view, partly in section, of the mechanism
of FIG. 4 .
DESCRIPTION OF PREFERRED EMBODIMENT
Referring to FIG. 1A, there is shown a prior art electromagnetic
vibrator 1, which is supported on each side via a trunnion 2 on
respective support pillars 3 and which is capable of rotation about
the trunnions 2. The vibrator comprises a drive coil 6 and a magnet
7 forming a magnetic circuit to drive the vibrator.
Referring to FIG. 1B, on the vibrator 1 is mounted a vertical
vibrating table 4, and on one side is disposed a horizontal
vibrating table 5.
For carrying out vertical vibration testing with the apparatus of
FIGS. 1A and 1B, the vibrator body 1 is held vertical, and the
vertical vibrating table 4 is mounted thereon, as shown in FIG. 1B.
The test body (not shown) is then mounted on the vertical vibrating
table 4, and then the drive coil 6 is energized to cause vertical
vibrations. For horizontal vibration testing, the vibrator body 1
is rotated about the trunnions 2 into its horizontal position, and
held horizontal. Then, the horizontal vibrating table 5 is coupled
on the vibrator 1. Thereafter, the test body (not shown) is mounted
on the horizontal vibrating table 5, and then the drive coil 6 is
energized to cause horizontal vibrations.
In the above-described conventional apparatus, however, when
coupling the horizontal vibrating table 5 to the vibrator 1, the
adjustment of the relative horizontal levels thereof requires a
high degree of skill. Also, it is necessary to provide equipment
for transferring the test body from the vertical vibrating table 4
onto the horizontal vibrating table 5. Further, the transfer of the
test body often causes damage thereto and also requires
considerable amounts of time. Furthermore, a considerably large
area is required for the installation of the transfer equipment in
addition to the relatively large vibrator unit and tables.
FIGS. 2 and 3 show an electromagnetic vibrator according to the
present invention. FIGS. 2A and 2B show the vibrator in the case in
which it is used for a vertical vibrating test, and FIG. 3 shows
the same for a horizontal vibrating test.
Referring to FIGS. 2A, 2B and 3, and particularly to FIG. 2B, which
is a section taken along line A--A in FIG. 2A, a stationary frame 8
supports a support shaft 9 which is rotatably journaled in frame 8.
The support shaft 9 carries two generally C-shaped permanent
magnets 10 secured thereto and spaced from each other such that
pairs of poles of one magnet respectively face opposite polarity
poles of the other magnet. The magnets 10 can rotate with their
shaft 9 by rotating a lever 11. Interposed between permanent
magnets 10 is a plate member 13 secured at its top to a vibrating
table 12. The plate member 13 is formed with a central opening or
aperture of a considerably greater diameter than the diameter of
the shaft 9 which passes therethrough, and it is provided on its
both sides with a drive coil 14 which is wound along the direction
of rotation of the permanent magnets 10, as is clearly shown in
FIGS. 2A and 3. The vibrating table 12 is supported via an air
spring means 15 on the stationary frame 8 by means, for example, of
angles 17 secured to frame 8. Other suitable supports can be
used.
Guide rollers 16 are provided and are ganged together such that
they can be alternatively supported either in their position shown
in FIG. 2A or in their position shown in FIG. 3. Generally L-shaped
guide plates 17 are secured to the plate member 13. The plate
member 13 is guided such that it can reciprocate only in the
vertical direction when the guide rollers 16 are in the position
shown in FIG. 2A, while it is guided such that it can reciprocate
only in the horizontal direction when the guide rollers 16 are in
the position shown in FIG. 3.
FIGS. 4 and 5 are enlarged views of one roller 16 and the mechanism
for moving the roller 16 in relation to the L-shaped guide plates
17. It is to be understood that the other three rollers and roller
moving mechanism are the same or similar to that illustrated in
FIGS. 4 and 5. As seen in FIGS. 4 and 5, a guide roller 16 is
rotatably mounted to a lever 18, the guide roller preferably being
mounted by means of a ball bearing mechanism 22. The lever 18 is
pivotally mounted to the frame 8 by means of a pin 19 which is
fixed to the frame 8 by means, for example, of screws 23 and
mounting block 24. An operating handle 20 is provided at the end of
lever 18 for pivoting the lever 18 about the pin 19 so as to change
the position of roller 16 relative to the L-shaped guide plate 17.
Operating handle 20 for each of the guide rollers may be
appropriately ganged together, as desired, so as to provide
simultaneous movement of the rollers.
When the roller and lever are in the position shown in solid lines
in FIG. 4, the guide plate 17 and vibrating table 12 can vibrate
(or reciprocate) only in the vertical direction. When the rollers
and levers 18 are moved to the position shown in dashed lines in
FIG. 4, the guide plate 17 and the vibrating table 12 can vibrate
(or reciprocate) only in the horizontal direction.
As mentioned above, the operating handles and levers 18 for each of
the rollers 16 may be ganged together. The ganging mechanism may
merely be a mechanical linkage which has not been shown so as to
not duly obscure the inventive concept. Alternatively, the handles
20 for the individual rollers 16 may be individually operable,
either by hand or by means of additional operating linkages (not
shown), as desired.
Vibration of the vibrating table 12 can be brought about by passing
A-C current at a frequency f through the drive coil 14. Because the
drive coil 14 is disposed to traverse the magnetic path formed by
the C-shaped permanent magnets 10, by passing A-C current at
frequency f through drive coil 14 there is produced a vibromotive
force F proportional to the product of the field and current in the
coil 14, which force F is given as
F = BlI
where F is the force (in kilograms), B is the flux density (in
gauss), l is the coil length (in centimeters) and I is the coil
current (in amperes).
The force F generated by the drive coil 14 in the above manner is
transmitted through the plate member 13 to the vibrating table 12
to cause vibration of a test body (not shown) mounted on the
vibrating table 12.
When the permanent magnets 10 are arranged such that their poles
lie in a vertical plane as shown in FIG. 2, by passing A-C current
through the drive coil 14, so that the plate member 13 and
vibrating table 12 are vibrated in the vertical direction. Thus, in
this case a vertical vibration test can be carried out on a test
article mounted on the vibrating table 12.
When the permanent magnets 10 are arranged such that their poles
lie in a horizontal plane as shown in FIG. 3, by passing A-C
current through the drive coil 14 a horizontal force is produced in
the coil 14, so that the plate member 13 and vibrating table 12 are
vibrated in the horizontal direction. It is to be noted that in
this case the guide rollers 16 are shifted to the position shown in
FIG. 3 so that the plate member 13 is guided such that it can
reciprocate in the horizontal direction. Thus, in this case a
horizontal vibration test can be carried out on a test article
mounted on the vibrating table 12.
The vibrating table 12 is mounted to the frame 8 by means of the
air spring 15 and angle members 21. This mounting techniquie is
used even when the table is vibrated in the horizontal direction.
In this case, therefore, the load on the guide rollers 16 is
reduced. The rotation of the permanent magnets 10 relative to the
table can be simply achieved by rotating the lever 11 which is
connected to shaft 9. Furthermore, vibrations not only in the
vertical and horizontal directions but also in any other desired
direction can be obtained by appropriately arranging the permanent
magnets 10 and guide rollers 16 at a desired position, such as a
position intermediate their two end positions.
While a preferred embodiment of the invention has been described in
the foregoing, it is by no means limiting and various changes and
modifications can be made to the above-described embodiment without
departing from the scope and spirit of the invention. For example,
the drive coil 14 may be provided only on one side of the plate
member 13. Also, the permanent magnets 10 may be replaced with
electromagnets, and different supports can be used in place of air
springs 15.
* * * * *