Note: Descriptions are shown in the official language in which they were submitted.
This invention relates generally to motor actuated
bells and more particularly to motor actuated bells of the
type in which a motor drives a hammer means through a
transmission means to allow the hammer to strike against
an associated gong with substantial impact, to thereby
produce a bell sound of great volume.
One conventional prior art motor actuated bell uses an
electric motor which rotates a cam via a gear train. The
cam intermittently acts on one end of a hammer, against
the action of a spring in order to drive the hammer
against a gong in order to produce a bell sound. This
prior art bell has the disadvantage that the motor must
provide substantial torque in order to produce a bell
sound of great volume.
SUMMARY OF THE INVENTION
It is therefore an object of this invention to provide
a motor actuated bell which is capable of producing a bell
sound of substantial volume without the need for a great
motor torque.
~o In accordance with an aspect of the invention there is
provided a motor actuated bell which comprises: (a) a gong;
(b) a base mounted with said gong; (c) a motor mounted on
said base and having a rotatable drive shaft; (d) a crank
member operatively connected to said motor drive shaft;
(e) an elongated connecting plate connected at one end
thereof to said crank member for reciprocal movement along
its axis generally in parallel relation to said base; (f)
a lever pivotally mounted on said base and connected at one
end thereof generally perpendicularly to the other end of
said connecting plate for swinging movement in parallel
spaced relation to said base; and (g) a hammer means having
a hammer element for striking against the inner wall of
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said gong, said hammer means having a resilient means
resiliently supporting said hammer element on said lever,
and the axis of said hammer element being disposed
perpendicularly to said lever.
BRIl~F DESCRIPTION OF THE DRAWINGS
In drawings which illustrate embodiments of the
invention:
FIG. 1 is a schematic perspective view of a motor
actuated bell constructed in accordance with the prior art;
FIG. 2 is a cross-sectional view of a motor actuated
bell in accordance with the present invention;
FIG. 3 is a partial schematic plan view of the bell;
and
FIGS. 4 to 6 are partial schematic views sllowing
modified bells.
One conventional motor actuated bell, is shown in FIG.
1. The bell is comprised of a small DC motor 100 having a
drive shaft 101 on which a gcar 102 is Eixcdly mounted.
wheel gear 103 fixedly mounted on a shaEt lO4 and engages
20 the gear 102. A cam l05 is moullted on thc sha~t LO~.
With this construction, thc motor 100 is driv~n to rotate
the cam ]05 through the mesllcd gcclrs 102, 103 so that the
cam intermittcntly acts on the encl of a hammer LOG. The
hammer strikes against arl associated ~Jong, against t:hc
bias of a coil spring 107, to procluce a bell sound. I'his
known motor driven bell has beel1 ~ound not entirely
satisfactory in that the motor must provide a substantial
; torque to enable the hammer to strike against the gong
with substantial impact to produce a bell sound of great
volume.
FIGS. 2 and 3 show a motor actuated bell 10. An
electric motor 11 is fixedly mounted on a mounting plate
or base 12 by screws 13. The motor has a drive shaft 14
- 2 -
t88
extending from the motor body in parallel spaced
relationship to the mounting plate 12. A crank member 15
is fixedly mounted on the motor drive shaft 14 for
rotation therewith. The crank member has a cylindrical
body 15a and an eccentric pin 16 formed integral with the
body. The eccentric pin 16 is disposed in eccentric or
offset relation to the axis of the drive shaft 14. An
elongated connecting plate 17 of a rectangular shape has a
slot 18 formed therethrough at one end thereof. The slot
lO extends across the width of the plate, i.e.,
perpendicularly to its longitudinal axis. The connecting
plate 17 is disposed in parallel spaced relation to the
mounting plate 12. The eccentric pin 16 is loosely
received in the slot 18, the pin having an enlarged head
16a for preventing the connecting plate 17 from becoming
disengaged therefrom. A rigid level 19, which is made,
for example, o~ a rigid synthetic resin, is pivotally
mounted intermediate opposite ends thereof on a post 20
which extends perpendicularly from the mountiny plate l2.
20 The lever 19 is disposed in parallel spaced relatioll!;hip
to the mounting plate 12. Tlle lcver 19 is rigidly
connected at one encl thereo~ to the end o~ the connectir
pl~te 17 remote ~rom the eccelltric pin ]6, the lever l9
extendinc3 througll tl-e conllecting plate and intersectin~3
the same substantially perpendicularly.
A hammer means 21 comprises a leaf spring 21a secured
at one end thereof by rivets 21b to the end of the lever
19 remote from the connecting plate 17, and a hammer
r element 21c secured to the other end of the leaf spriny
30 21a.
As shown in FIG. 3, the length of the eccentric pin 16
between the inner face of the head 16a and the end Eace
15b of the cylindrical crank body 15a is greater than the
thickness of the connecting plate 17 to permit a slight
lateral movement of the plate 17.
As shown in FIG. 2, the mounting plate 12 is arranged
within and connected to an inverted cup-shaped gong or
bell 22 by a connecting member 23 of a generally channel-
shaped cross-section. The connecting member 23 is fixedly
secured to the mounting plate 12 and the gong 22 by screws
24.
In operation, the motor ll is driven through a power
source (not shown) to rotate the crank member lS in a
clockwise direction (FIG. 2) to allow the eccentric pin 16
to revolve around the drive shaft ],4. During a ~irst half
of the revolutlon of the pin 16, the pin, which is
disposed Oll the left side of the drive sha~t 1~ (FIG. 2)
; with its axis and the axis of thc drive shaft 14 lyinc3 in
a common plane parallel to the mountillg plate 12, is
angularly moved through ]~0 so tl-at the pin 16 is held in
sliding contact with the right s,id(! cdge o~ thc? slot 18 to
move the connectin~ plate l7 in a right-hancl clircction.
The connecting plate 17 thercby cau5cs the levc,~r l9 to
pivot about the post 20 so that thc hammcr element 21c
strikes against the inner wall of the gong 22 to produce a
bell sound. During the other half of the revolutioll of
the eccentric pin 16, the pin is angularly moved through
180 so that the pin 16 is held in sliding contact with
the left side edge of the slot 18. This moves the
connecting plate 17 in a left-hand direction~ The
connecting plate 17 thereby causes the lever l9 to pivot
about the post 20 so that the hammer element 21c is moved
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away from the gong 22.
This cycle of operation is continuously repeated to
impart a swinging motion to the hammer means 21 so as to
produce a bell sound of the required volume. When the
hammer means 21 is moved to its fully retracted position
from the gong 22, the leaf spring 21a is slightly flexed
in a direction away from the gong so that the restoring
force of the flexed leaf spring 21a enhances the striking
of the hammer element 21c against the gong 22.
According to a modified form of the invention shown in
FIG. 4, a rigid lever 30 is pivotally mounted on the post
20 at approximately its center. The lever 30 has a hammer
means 31 secured to its free end remote from the
connecting plate 17. The hammer means comprises a hammer
element 31a and a resilient means 31b in the form of a
coil spring interconnecting the hammer elemellt 31a and the
lever 30. The operation oE this mo(liEied bell is
substantially similar to that o~ the bell 10 shown in
; FIGS. 2 and 3. When the hammer mecllls 31 is movcd to its
fully retracted position from the goncJ 22, the coil spring
31b is axially contracted so tilat: the restoriny ~orce of
the thus contracted coil spring 31b encllances the striking
of the hammer element 31a against the gong 22, depcnding
on the spring constant of the coil spring 31b ancl the
speed of rotation of the motor drive shaft 14.
FIG. 5 shows another modification in which a rigid
lever 35 is pivotally mounted on a post 20a at one end
thereof remote from the connecting plate 17. The lever 35
has a hammer means 36 mounted thereon intermediate its
opposite ends. ~he hammer means 36 comprises an elongated
hammer element 36a of a cylindrical shape having a head
3~
36b. Hammer element 36a is slidably received in a hole
~not shown) formed thLough the lever 35. A pair of coil
springs 36c, 36d are wound around the hammer element 36a
on opposite sides of the lever 35. A collar 36e is
fixedly mounted on the end of the hammer element 36a
remote from the hammer head 36b. The coil spring 36c acts
between the hammer head 36b and the lever 35 while the
coil spring 36d acts between the collar 36e and the lever
35.
When the motor 11 is driven, the lever 35 is pivotally
moved about the post 20a toward and away from the gong 22
by the crank member 15 and the connecting plate 17 so that
the hammer head 36b strikes against the gong 22 to produce
a bell sound. When the hammer el.ement 36a is moved to its
fully retracted position from the gong 22, the coil. s~ring
36c is axially contracted so that the rt-~storing ~rce of
the contracted coil spring 36c enhclnces the striking oÇ
the hammer head 36b aga:inst the gong 22 dcpt!ntlin~ on the
spring constant of tht-~ coil spring 36c and the spet;~d of
rotation o~ the motor drive sllaft :L4.
~ ccording to a Çurther modiÇication of tht? invention
shown in FIG. 6, a rigid lever 40 oÇ a c~erleral.:ly el.ot-gated
oval shape has a pair of spaced arms 40a, 40b and a pair
of ring porti.ons 40c, 40d at its opposite ends. A
connecting plate 17a has an integral pin 17b at one end
thereof remote from the crank member 15. The pin 17b and
an upstanding post 20b are received in the ring portions
40c, 40d, respectively, so as to provide a pivotal
connection. A hammer means 41, whic.h is identical in
construction to the hammer means 36 shown in FIG. 5, is
mounted on the lever 40 intermediate opposite ends
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thereof. A hammer element 41a extends through the arms
40a, 40b for sliding movement along its axis. A coil
spring 41c acts between a hammer head 41b and the arm 40a
while a coil spring 41d acts between the arm 40b and a
collar 41e.
As described above, the resilient means in the form of
a leaf spring or coil springs associated with the hammer
element aids in imparting sufficient momentum to the
hammer element to allow the hammer to strike against the
gong with substantial impact so that a bcll sound of great
volume is produced.
While the motor actuated bells according to this
invention have been specifically shown and described
herein, the invention itself is not to be restricted by
the description. For example, a speed reducer may be
connected to the motor drive shaft to actuate thc hammer
at a lower speed.
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