U.S. patent number 3,787,641 [Application Number 05/259,489] was granted by the patent office on 1974-01-22 for bone conduction microphone assembly.
This patent grant is currently assigned to Setcom Corporation. Invention is credited to Charles M. Santori.
United States Patent |
3,787,641 |
Santori |
January 22, 1974 |
BONE CONDUCTION MICROPHONE ASSEMBLY
Abstract
A bone conduction microphone assembly with a transducer mounted
in a transducer mount supported from a surrounding support member
by spring means which yieldably urges the transducer mount against
the user's head with predetermined pressure.
Inventors: |
Santori; Charles M. (San Jose,
CA) |
Assignee: |
Setcom Corporation (San Jose,
CA)
|
Family
ID: |
22985169 |
Appl.
No.: |
05/259,489 |
Filed: |
June 5, 1972 |
Current U.S.
Class: |
381/151;
381/368 |
Current CPC
Class: |
A42B
3/30 (20130101); H04R 1/46 (20130101); H04R
1/14 (20130101) |
Current International
Class: |
A42B
3/04 (20060101); A42B 3/30 (20060101); H04R
1/14 (20060101); H04R 1/46 (20060101); H04R
1/00 (20060101); H04r 025/00 () |
Field of
Search: |
;179/17BC,108,1MF,156,179 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Blakeslee; Ralph D.
Attorney, Agent or Firm: Flehr, Hohbach, Test, Albritton
& Herbert
Claims
1. A bone conduction microphone assembly comprising an acceleration
sensitive transducer, a transducer mount adapted to receive and
hold said transducer, a transducer support having an opening larger
than said transducer mount for receiving said transducer and mount,
said support surrounding and spaced from said transducer mount and
a plurality of spring means connected between said transducer mount
and said transducer support to hold the transducer in said opening
and yieldably urge the transducer against the head of a user with
predetermined pressure when the
2. A bone conduction microphone assembly comprising a transducer
mount having upper and lower surfaces, a transducer of the type
which provides an output responsive acceleration held in said
mount, a support having upper and lower surfaces and an opening
larger than said transducer mount for receiving said transducer and
mount, said support surrounding and spaced from said transducer
mount, spring means extending between said transducer mount and
support serving to support said transducer mount in said opening
with the lower surface of said transducer mount extending beyond
the lower surface of said support whereby when the microphone
assembly is placed on a user to pick up bone vibrations the
transducer is yieldably urged against the user to move as the
associated bones vibrate.
3. A bone conduction microphone assembly as in claim 2 wherein the
upper surface of said support is above the upper surface of said
transducer
4. A bone conduction microphone as in claim 1 wherein said support,
transducer mount and spring means are formed as a unitary molded
assembly.
5. A bone conduction microphone assembly as in claim 4 wherein said
spring
6. A bone conduction microphone assembly as in claim 1 including a
mounting assembly cooperating with said support for mounting said
assembly to
7. A bone conduction microphone assembly comprising an acceleration
sensitive transducer, a transducer mount adapted to receive and
hold said transducer, a support surrounding and spaced from said
transducer mount, a plurality of spring means cooperating between
said mount and said support to yieldably urge the transducer
against the head of a user with predetermined pressure when the
support rests on the head of a user, a mounting assembly including
spaced mounting members secured to said support for mounting said
assembly to associated head gear, and damping means sandwiched
between said spaced mounting members.
Description
BACKGROUND OF THE INVENTION
This invention relates generally to a bone conduction microphone
assembly and more particularly to a bone conduction microphone
assembly suitable for use in a variety of head gear.
Bone conduction microphones operate from energy generated by
auditory vibrations of the bones in the head. The microphone
transducer is generally a sensitive, low mass accelerometer in
intimate contact with the head to pick up the bone vibrations and
generate output signals responsive to the auditory vibrations. In
many applications the microphone is used by persons who require the
use of both hands and in relatively noisy environments. Normally,
in such environment the microphone is used in conjunction with some
type of head gear such as industrial hard hats, fire, motorcycle,
riot and police helmets.
Prior art microphones have serious limitations in such
applications. They are adversely affected by ambient noise
transmitted through the air or through the head gear from which
they are supported. Their size and shape make it difficult and
often impossible to mount the transducers in the head gear and so
in many instances, when mounted, render the head gear
uncomfortable. In some instances, transducers mounted in the head
gear are hazardous in that a hard blow to the head gear may drive
the transducer into the head and cause injury. The audio quality
is, in general, poor because the transducer is not held in intimate
contact with the head with sufficient pressure to pick up high
frequency vibrations whereby high frequency sound is not
effectively reproduced.
OBJECTS AND SUMMARY OF THE INVENTION
It is a general object of the present invention to provide an
improved bone conduction microphone assembly which can operate in
very high ambient noise conditions.
It is another object of the present invention to provide a bone
conduction microphone assembly in which the microphone mount is
yieldably pressed against the head with predetermined force to give
a satisfactory consistent pressure whereby the microphone operates
effectively over a broad frequency spectrum.
It is another object of the present invention to provide a bone
conduction microphone assembly with improved protection against
possible injury by the transducer under impact forces.
It is still a further object of the present invention to provide a
bone conduction microphone assembly which is readily adapted to fit
a variety of head gear which can be comfortably worn by the
user.
The foregoing and other objects of the invention are achieved by a
bone conduction microphone assembly which includes an acceleration
sensitive transducer, a transducer mount adapted to receive and
hold said transducer, a support structure including a hole for
receiving the transducer mount to surround and be spaced therefrom,
and spring means cooperating between said transducer mount and said
support to yieldably urge the transducer against the head of the
user with predetermined pressure when the support rests on the head
of the user.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a side view partly in section showing the bone conduction
microphone assembly in use with a helmet.
FIG. 2 is a view taken along the line 2--2 of FIG. 1 showing the
bone conduction microphone assembly held by the helmet suspension
straps.
FIG. 3 is an exploded view of the bone conduction microphone
assembly shown in FIGS. 1 and 2.
FIG. 4 is a sectional elevational view of the bone conduction
microphone assembly.
FIG. 5 shows the bone conduction microphone applied to the head
surface.
FIG. 6 is a perspective view of another embodiment of the bone
conduction microphone assembly of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The bone conduction microphone assembly of the present invention is
particularly suitable for use in head gear such as industrial hard
hats, fire, motorcycle, riot and police helmets. Referring to FIG.
1, a user 11 is shown wearing a protective helmet 12. The helmet
includes a headband 13 and suspension straps which hold the helmet
on the head of the user with the protective portion of the helmet
spaced from the head. The straps 14 extend upwardly from the
headband 13 and engage a loop 16, FIG. 2. The loop 16 is, in turn,
sandwiched between Velcro tabs 17 more clearly shown in FIG. 4, 17a
and 17b.
Referring particularly to FIG. 3, the bone conduction microphone
assembly includes a transducer support 21 which includes a central
hole or opening 22. A transducer mount 23 is disposed within and
spaced from said opening whereby the transducer support 21
surrounds and is spaced from the transducer mount. A plurality of
radially extending spring members 24 are adapted to support the
transducer mount from the surrounding transducer support. As will
be more clearly described, the springs 24 serve to yieldably urge
the transducer mount against the head of a wearer to provide
intimate contact whereby the transducer mount can effectively pick
up the bone vibrations. The transducer and mount are, therefore,
isolated from the main support reducing the noise vibrations which
can be transmitted through the support.
The transducer mount includes a well 26 adapted to receive and hold
the transducer 27. The mount protects and holds the transducer and
yet permits the transducer to respond to minute vibrations of the
head bones. The transducer 27 is a sensitive low mass accelerometer
as, for example, the type manufactured and sold by Knowles
Electronics Inc., its Model No. BL1670. Insulated transducer wires
28 extend outwardly from the transducer and are connected to a
cable 29. A grommet or other suitable stop 31 is provided on the
cable 28. The transducer support member includes a groove or slot
32 adapted to receive the cable with a cross slot 33 adapted to
receive the grommet or stop 31 whereby to provide strain relief.
The effect of cable vibrations on the transducer is minimized by
use of fine transducer wires and by securely attaching the cable to
the relatively high mass support member.
The transducer support is provided with a cover 36 which is
suitably secured to the top surface of the surrounding support and
is adapted to hold the cable in place and to provide a recess or
clearance at the top of the transducer mount for purposes to be
presently described.
In accordance with the embodiment of the invention shown in FIG. 3,
the transducer support includes an encircling or mounting portion
37 which extends outwardly and has its lower surface coplanar with
the lower surface of the transducer support. A damping pad 38 which
may, for example, be made of an expanded material, such as
Scottfelt, is adapted to surround the support and rest against the
upper surface of the mounting member 37. A vinyl cover with Velcro
pads 17b secured at spaced points is suitably affixed to the upper
surface of the damping pad and to the upper surface of the
microphone cover 36 whereby to provide an assembly of the type more
clearly shown in FIG. 4. As a result, the bone conduction
microphone assembly including its supporting ring, cover,
microphone mount and spring means is held on the helmet loop 16 by
the Velcro tabs 17a, 17b and is substantially isolated therefrom by
means of the damping afforded by the Velcro tabs and by the damping
pad 38. The microphone assembly is effectively isolated from
vibrations of the helmet and helmet straps.
Referring particularly to FIG. 4 showing the assembly, it is noted
that the lower surface 41 of the transducer mount 23 extends beyond
the lower surface 42 of the transducer support member. The
transducer mount 23 is held in this extended position by means of
the spring members 24. The transducer mount, support and spring
members may be formed of the same material, for example rubber, in
one molding operation. When the transducer support is mounted on
the head surface 42 as shown in FIG. 5, the lower surface 42 of the
support rests against the head 43 and the spring members 24 are
bent upwardly and provide a yieldable downward force so that the
lower surface 41 of the transducer mount rests intimately against
the head surface 43 to provide good contact to transfer bone
vibrations to the transducer. It has been found that by yieldably
urging the transducer mount against the head, good frequency
response is obtained.
Referring again to FIG. 4, it is seen that the upper surface 44 of
the transducer support cover is spaced above the upper surface 46
of the transducer mount to provide a recess. Referring to FIG. 5
showing the transducer mounted on the head of a user, it is seen
that the upper surface of the transducer mount, even in its mounted
condition, is below the upper surface 44 of the cover 36. In this
way, any hard impact to the hat which would otherwise make the
helmet itself strike the microphone transducer will strike the
large surface 44 distributing the impact forces over a considerable
area and preventing injury to the user.
It is apparent that the bone microphone transducer assembly
described can be used with other types of supports 37. Referring to
FIG. 6, another embodiment of the bone conduction microphone
assembly is shown. The microphone of this embodiment can be
associated with other types of supports.
* * * * *