Microphone support with simultaneous adjustment of plural degrees of freedom

A microphone (11) is secured to one end of a unidirectionally flexible tape (12) which is removably storable in a housing (10) after passage through a tracking mechanism (13). That mechanism is part of a further mechanism (26, 37, 41) for holding an exiting portion of the tape in the angular orientation assumed by the tape at the end of a removal operation.

TECHNICAL FIELD 
This invention relates to a microphone support, and it relates more 
particularly to such a support for use in mobile radiotelephone 
applications. 
BACKGROUND OF THE INVENTION 
In mobile radiotelephone applications, it is, at times, desirable to have 
facilities for hands-free operation so that the driver of the vehicle need 
not hold a microphone or other handset while driving. It is assumed 
without limitation that the driver is the principal radiotelephone user. 
It has been found that many mobile unit users dislike microphones which 
are attached to their person or to their clothing in the manner often 
observed in the entertainment industry. In a more technical sense, it is 
further desirable that any microphone be located relatively close to a 
user's mouth in such a way as to be readily deflectable in the event of a 
change in position of the body of the user. Furthermore, the microphone 
should be so locatable with a minimum of distraction to the user. 
There are a wide variety of adjustable support arrangements for subscriber 
telephone apparatus including microphones. One example is found in the A. 
Hufschmid U.S. Pat. No. 2,048,865 in which a handset articulated support 
of plural links is flexible in only one direction because the links are 
secured together by off-center transverse pins. In such an arrangement, 
there is basically one fixed radius of extended position, and adjustable 
set screws are provided to fix the height and angle of the extended 
support. An electric cord for the handset extends through the links and 
through an unpivoted end of a rotatable support for the multilink flexible 
support. It is at once apparent that substantial user attention is 
required in order to make the various adjustments for correctly 
positioning the multilink support member. 
SUMMARY OF THE INVENTION 
The problems of prior adjustable support arrangements for a microphone are 
alleviated in accordance with the present invention which employs as a 
microphone support an unarticulated member that is configured to allow 
flexure in substantially only one direction.

DETAILED DESCRIPTION 
FIG. 1 shows a perspective view of a hands-free microphone housing 10 
utilizing the present invention. The housing is illustratively mounted in 
an automobile (partially indicated by broken lines) above the door next to 
the driver or other occupant most likely to use radiotelephone equipment 
with which the microphone is associated. A microphone 11 is secured to a 
free end of an elongated flexible member such as an unarticulated tape 12 
which is configured (as will be described) to be flexible in one direction 
which is transverse to the longitudinal axis of the tape. That direction 
is, in terms of FIG. 1, substantially parallel to the housing 10 when the 
tape 12 is extended substantially perpendicularly to the housing. 
When microphone 11 is removed to a usage position, tape 12 exits from the 
housing 10 through a stub boom 13 which is part of a tape orientation 
tracking and holding mechanism (to be described). That mechanism tracks 
the tape angular position with respect to the housing and, upon 
termination of a removal operation, holds an exiting portion of the tape 
adjacent to the boom in its position at that time as to both the extent of 
removal from the housing and the tape orientation as removed. When the 
tracking and holding mechanism is actuated to release the tape, a 
retracting mechanism in the housing 10 restores the tape in the housing 
and restores the boom 13 to a home position in a housing recess 16 for the 
boom and microphone 11. Housing 10 also advantageously includes a volume 
control knob 17 for adjusting the volume in a loudspeaker circuit 
connected to the remainder of the radiotelephone apparatus (not shown) by 
rotating the knob. In addition, however, the knob is also advantageously 
arranged, in a manner now well known in the art, to be pushed in or pulled 
out along its rotational axis for controlling another function. In this 
case the other function is the release of the aforementioned tape 
retracting apparatus. Housing 10 further includes a loudspeaker, as 
schematically indicated by the louvers 18 and in the housing 10, as well 
as electronics normally associated with the hands-free type of microphone 
and speaker combination, now well known in the art and not comprising a 
part of the present invention. 
FIG. 2 shows a front elevation view of the housing 10 with the microphone 
11 and boom 13 in their home positions in the recess 16. 
FIG. 3 presents a cross-sectional view of the contents of the housing 10 
taken at lines 3,3 in FIG. 2. This cross-sectional view depicts the 
aforementioned tracking, holding, retracting, and releasing mechanisms. 
The housing 10 is, for example, a relatively rigid, formed metallic 
material which provides electromagnetic shielding between the microphone 
tape cable 12 and any other electric circuits which may be situated in the 
upper portion of the housing 10 in FIG. 2. 
The stub boom 13 includes a ball 20 on one end thereof which is held in a 
socket 21 to form a swivel coupling between the boom 13 and the housing 
10. The boom 13 includes a curving funnel shaped aperture 22 extending 
between the upper surface and the right-hand end surface of the boom as 
illustrated in FIG. 3. The large portion of the aperture 22 is in the 
upper (as shown in FIG. 3) face of the boom 13. Tape 12 passes through the 
aperture 22 and into an aperture 23 in a brake arm 26 on the way to a 
retraction coupling slider block 27 and a mechanical anchor point 
illustrated in the form of a clamp 28 which secures an end portion of the 
tape 12 to a nearby wall of the housing 10. A central portion of the FIG. 
3 structure is broken out for convenience of illustration but is of 
sufficient length to allow tape extension a desired maximum distance from 
housing 10. Terminals for making electrical connections to conductors in 
the tape 12 are advantageously at connectable 29 the loose ends of these 
conductors. As will be subsequently further described, the tape 12 is 
advantageously a flexible tape having a predetermined transverse curvature 
when the tape is not subjected to external forces. Thus, in FIG. 3, the 
longitudinal edge view of the tape 12 shows simply the tape material 
thickness in locations where the tape is being held against another 
member. However, although not specifically shown in FIG. 1 portion of the 
aperture 22 where the tape is relieved of forces holding it against walls 
of passageways, it resumes its natural unrestrained curvature. 
The brake arm 26 pivots about an axle 30 and is urged by a coil spring 31 
in a counterclockwise direction about the axle 30 to force a brake pad 32 
through a hidden slot in the socket 21 to come into frictional engagement 
with the ball 20. This frictional engagement under the action of spring 31 
has a sufficient force normally to hold the boom 13 in position against 
the pull of gravity and untoward accelerations. Tape 12 passes around a 
curved surface on the right-hand portion of each of the apertures 22 and 
23, and when the tape is under tension in excess of that exercised by 
gravity, etc., it exerts a clockwise rotational force on the brake arm 26 
to release the engagement between brake pad 32 and the ball 20. 
Thus, as the microphone 11 and tape 12 are pulled out of the housing 10, 
the clockwise movement of the brake arm 26 releases ball 20 and allows the 
boom 13 to swivel out of its FIG. 3 home position to an extended position 
such as that illustrated in FIG. 1. Likewise during the removing 
operation, the force exerted by the tape against the walls of the aperture 
22 in the boom 13 causes the boom to track the tape angular orientation 
with respect to the housing 10. When the removing operation terminates, 
the tape 12 is otherwise locked with the extent of removal thus attained 
(as will be described) so that the only tension on the part of the tape 
extending through the apertures 22 and 23 is that due to the weight of the 
microphone 11 and the tape 12. Spring 31 then drives brake arm 26 in a 
counter clockwise direction to hold the ball 20 and the boom 13 in the 
angular orientation position thus attained. 
It will be apparent that different drivers are likely to require microphone 
11 positions which are unique to their respective needs so that the boom 
13 may not turn in a plane which is perpendicular to the face of the 
housing 10. Departures from such perpendicularly will impose a limited 
amount of twist about the longitudinal axis of the tape 12, but such 
twisting will be limited to the region of the tape held between the sides 
of the apertures 22 and 23. 
In order to avoid a need for sliding electrical contacts sometimes found in 
reel-type retraction mechanisms, the tape 12 passes through a first 
semicircular passage 33 in the slider block 27 and exits from the same 
face of that block to the clamp 28 already mentioned. It will be noted 
that the central portion of the apparatus in FIG. 3 is broken away, i.e., 
from a point near the lefthand side of recess 16 to a point first to the 
left of block 27 in its rightmost position, since the intervening part of 
the apparatus is merely connective and adds nothing to an understanding of 
the invention. However, tape 12 is also broken away just to the right of 
clamp 28 to indicate schematically that the clamp is actually located near 
the wall of recess 16 to allow maximum clearance for leftward movement of 
block 27. Block 27 is slidably fitted between the walls of the housing 10 
to move right or left as illustrated in the drawing without binding on 
those walls. A second semicircular passage 36 in the block 27 accommodates 
a constant force spring 37 which is normally largely wound upon a drum 38 
which is rotatably mounted on an axle 39. Spring 37 enters the passage 36 
in the right-hand face of the block 27 and exits through the same face at 
the other end of the passage. A clamp 40 secures the otherwise free end of 
the spring 37 to the wall of the housing 10 as shown in FIG. 3. 
In order to remove the microphone 11 and tape 12 from the housing 10, an 
appropriately directed force is applied by the user to position the 
microphone 11 at a convenient point in front of his mouth. This removal 
force on tape 12 draws the block 27 to the left against the force of the 
spring 37. Upon removal of the tape removing force, spring 37 tends to 
rewind itself upon the drum 38 and thereby pull the block 27 to the right 
to return it to the position illustrated in FIG. 3 and thus retract the 
tape and the microphone into the housing. Of course, for mobile 
radiotelephone applications, the user wants the microphone and tape to 
remain in the removed position selected by the user during the telephone 
communication. Therefore, an automatic spring braking mechanism is 
provided. This mechanism is in the form of a rotatable brake member 41 
which rotates on an axle 42 and is provided with a yoke portion 43. The 
yoke portion holds a resilient brake pad 46 in order to bind the spring 37 
between the pad and the adjacent wall of the housing 10 in the illustrated 
position of the yoke with the pad displaced slightly to the left of the 
rotational axis of the axle 42. A torsion spring 47 extends around the 
axle 42 and includes end portions engaging the yoke 43 and a latching pawl 
48. That pawl is mounted for rotation on a further axle 49 which has its 
rotational axis in the same plane with the rotational axes of axles 39 and 
42. Thus, in the illustrated position of the brake member 41, the spring 
47 urges the brake member 41 in a clockwise direction and urges the pawl 
48 in a counterclockwise direction. 
When the block 27 moves to the left, during removal of the tape 12 from the 
housing, against the combined forces springs 37 and 47, brake member 41 
rotates slightly in the counterclockwise direction thereby releasing 
spring 37. When the removing action ceases, spring 37 starts to rewind 
itself on the drum 38; but, since pad 46 is still touching spring 37, 
brake member 41 is thereby caused to rotate in a clockwise direction and 
once again grips spring 37 to prevent further retraction. When a user 
wishes to retract the microphone 11 into the housing 10, it is necessary 
simply to push the volume control knob 17 upward as illustrated in FIG. 3. 
This action causes the end of the volume control shaft 14 to drive a 
flexible arm 50 against a shoulder 57 on the brake member 41 to rotate 
that member in the counterclockwise direction and thereby release the 
braking action. If knob 17 is completely depressed, member 41 turns far 
enough to allow a latching pawl 48 to engage member 41, as will be 
described, and thereby hold the brake released. This permits spring 37 to 
rewind itself upon the drum 38 until the slider block 27 restores pawl 48 
to its illustrated position where block 27 is blocked by the pawl 48 from 
further movement to the right. Release of member 41 allows the torsion 
spring 47 to reestablish the braking action on tape 37 and drive the 
volume control knob back to its normal position. 
Brake member 41 is also provided with an inertial mass portion 52 located 
with respect to the axle 42 so that sudden deceleration of the vehicle in 
which the housing is mounted will cause counterclockwise rotation of the 
brake member 41 through a sufficient arc so that a face 53 of the inertial 
mass portion 52 passes a latching face 56 on the pawl 48. Consequently, 
the pawl is free to rotate in a counterclockwise direction in response to 
the force supplied by the torsion spring 47 assuming that tape 12 is in a 
sufficiently extended position so that block 27 has been displaced toward 
the left a sufficient amount to allow the required pawl rotation. A 
passageway 55 between the left-hand and right-hand faces of pawl 48 had 
initially allowed air flow as block 27 moved to the left during tape 
extension to prevent vacuum drag on the block and a similar vent 58 in the 
right-hand wall of housing 10 cooperates to that end. However, the 
passageway 55 is closed by the mass portion 52 when it is latched by pawl 
48. The turning of the pawl 48 locks the brake member 41 in a rotated 
position as illustrated, for example, in FIG. 5 and automatically 
maintains the brake released until tape 12 has been retracted. 
Spring 37 rewinds itself to accomplish that retraction and correspondingly 
slides block 27 to the right. Passageway 55 is closed by mass 52 while it 
is latched in the brake-released position so that pawl 48 blocks 
substantial air flow to provide pneumatic cushioning for block 27 just 
before it strikes pawl 48. When the block strikes the rotated pawl 48, 
that pawl is thereby restored to the normal position illustrated in FIG. 3 
for reengaging the braking member 41 with the spring 37. 
In applications of the invention where clearances within housing 10 are 
sufficient to permit spring 37 to become unstable and to become kinked in 
the region between drum 38 and the block 27, spring edge retaining grooves 
(not shown in the drawing) are secured to walls of housing 10 in 
appropriate regions to restrain the tendency toward instability. The width 
of portions of spring 37 in and adjacent to passage 36 are narrower than 
the rest of the spring to permit passage between such grooves. 
FIG. 6 illustrates in transverse section one embodiment of the tape 12 in 
accordance with the present invention. In this embodiment, three flat 
strip conductors 59, 60, and 61 of an electrically conductive material 
such as copper are spaced in parallel relationship on a longitudinal 
edge-to-edge basis. Layers of insulation 54 enclose and electrically 
separate the conductors. An electromagnetic shielding layer 62 is applied 
around the insulated conductors 59-61. One example of such a material is 
aluminized polyethylene terephthalate plastic. A folded lap joint is 
utilized in layer 62 between conductors 59 and 60 to facilitate continuous 
electrical contact in the aluminized layer which usually is on only one 
side of the layer. The shielded assembly is then enclosed in a further 
layer of polyethylene terephthalate plastic to provide an assembly which 
is impervious to air and water and which has a transversely curved 
cross-section as shown in FIG. 6 when the tape is in its unrestrained 
condition. This configuration of the tape, plus its corresponding 
positional restraint of the flat conductors 59-61, allows the tape to bend 
upward, as illustrated in FIG. 6, about a transverse axis, e.g., in the 
plane of the drawing. The same transverse curvature of the tape also 
prevents similar downward bending as well as preventing bending to the 
right or to the left unless accompanied by a corresponding twisting force 
acting about the longitudinal axis of the tape. A tape having a width W of 
approximately 0.25 inches advantageously has a cross-sectional height, 
i.e., chordal depth of curvature, of approximately W/6 for a tape of 
approximately 0.015 inches in thickness. Tapes of such dimensions readily 
support microphones such as those conventionally found in hearing aids and 
weighing approximately 1 gram when the tape is extended distances suitable 
for mobile radiotelephone use, e.g., about 18 inches. Microphones of that 
type are typically of about the same width as the tape and when housed in 
a thin case centralized to the thickness of the tape apply insufficient 
torque to twist the tape. 
Tape 12 threads the various passageways in FIG. 3 so that the concave face 
of the tape is toward the inside of all curves that must be negotiated. 
The configuration illustrated in FIG. 6 does allow an apparent departure 
from the flexibility limitations mentioned if a twisting force is applied 
about the longitudinal axis of tape in excess of a predetermined threshold 
which depends upon the materials and the dimensions of the tape. However, 
as indicated in connection wth FIG. 3, normal operation of the invention 
involves twisting effects only between the boom 13 and the brake arm 26 
where the twisted tape portion is supported at both ends. 
FIG. 7 illustrates in transverse section another embodiment of the 
invention which still utilizes the same overall transverse curved 
configuration. In this embodiment, two conductors 62 and 63 of circular 
cross-section are arranged near the longitudinal edges of the tape. A 
central transversely curved metallic strip conductor 66 of, for example, 
phosphor bronze provides a ground conductor for circuits utilizing the 
conductors 62 and 63. The three conductors are advantageously encapsulated 
in polyethylene terephthalate plastic 64. In this embodiment, the curved 
strip 66 enhances the previously described single degree of freedom of 
flexibility for the tape. 
In applications of the invention wherein extra rigidity is useful in 
directions other than that of the single degree of freedom of flexibility, 
a messenger strip is advantageously provided. Such a strip is the 
transversely curved metallic strip 72 in FIG. 7. This strip, which is 
advantageously spring steel, is of the same length as strip 12 and secured 
to it at each end but otherwise free to slip longitudinally or 
transversely with respect to strip 12. 
FIG. 8 illustrates a further embodiment including three flat strip 
conductors 67, 68, and 69 encapsulated in the aforementioned plastic 
material 65, but in this embodiment the conductors lie in a flat co-planar 
edge-to-edge arrangement. A ridge 70 extends along the length of the tape 
in the center of one side and has multiple cuts 71 through the height of 
the ridge at regular intervals as illustrated in FIG. 9. These cuts allow 
the unidirectional degree of freedom of flexibility previously described. 
However, this arrangement requires enlarged passages in the tape tracking, 
holding, and retracting mechanisms. 
FIG. 10 is a top view of the embodiment of FIG. 1 with the microphone and 
boom extended and viewing the tape in longitudinal edge profile. In the 
event of a movement by the vehicle driver to his left or forward (up or to 
the right as illustrated in FIG. 10) the microphone 11 which has been in 
position in front of the driver's mouth is easily deflected to, e.g., the 
dotted line position illustrated in FIG. 10, because that is the single 
direction of free flexibility of the tape in configurations such as those 
illustrated in FIGS. 6 through 9. 
FIG. 11 shows a cross-sectional view, as in FIG. 3, of a different 
embodiment of the tape tracking and holding mechanism. For this case, the 
slider block 27 and retracting mechanisms are the same as in the 
right-hand portion of FIG. 3. A cylindrical swivel 92, shown in 
perspective in FIG. 16, is supported for rotation in housing 10 by 
bearings 95. A cantilever spring 96 at the right-hand end is positioned 
between two lugs 97 (only one of which is specifically shown) to define a 
central position for swivel 92 from which the swivel can be rotated about 
45 degrees in either direction. Spring 96 returns to swivel to its central 
position when the swivel is released. 
A central aperture 103, seen best in FIG. 16, extends transversely through 
the swivel 92 to accommodate a stub boom 80, a brake link 86, and a 
pivotable link 83. The boom 80, which is shown in perspective in FIG. 17, 
includes the aperture 22' for passage of tape 12 and is mounted for 
rotation on an axle 81 which is supported in receiving openings 81' (one 
shown in FIG. 16) in swivel 92. As shown in FIG. 11, boom 80 is in its 
home position in swivel 92 and is essentially flush with the surface of 
that swivel except for a knurled portion 93 to the left and below axle 81. 
A user need only apply thumb pressure to the portion 93 to turn the 
right-hand portion of boom 80, along with microphone 11, out of swivel 92 
to facilitate the grasping of the microphone for extension. Boom 80 can 
thereafter be turned up to about 135 degrees clockwise from its home 
position. 
The holding mechanism includes the brake link 86, also rotatably mounted on 
the axle 81, and pivotable link 83 rotatably mounted, on an axle 87, in 
the aperture 103. Axle 87 is supported in receiving openings 87' (one 
shown in FIG. 16) in swivel 92. Links 86 and 83 are further illustrated in 
perspective in FIGS. 14 and 15, respectively. As is best seen in the 
cross-sectional view of FIG. 12, link 86 is positioned between the two 
branches of the bifurcated left end of boom 80. A pin 84 interconnects the 
right-hand end of link 86 and the left-hand end of link 83 so that as tape 
12 is drawn out of housing 10 link 83 is turned clockwise about axle 87 
and in turn drives link 86, through pin 84, in a counterclockwise 
direction against the action of a biasing coil spring 89. This turning 
moves a resilient friction member 88, with an internal reinforcement axle 
90, out of engagement with the wall of housing 10 so that cylindrical 
swivel 92 is thereby freed to turn as required to track the position of 
tape 12. Member 88 floats in a saddle groove 104 in link 86 and is free of 
boom 80 in its home position. Member 88 is driven against the wall of 
housing 10 by turning a link 86 in a clockwise direction. Two radial 
braking surfaces 105 and 106 are provided inside each of the bifurcation 
branches of boom 80 to be engaged by member 88 when tape tension is 
released. Sector 106 has a smaller radius about axle 81 than does sector 
105 so that initial rotation of boom 80 from the home position will not 
inadvertently actuate the braking function of member 88 even if the 
tension on tape 12 should be momentarily released. Since the braking 
mechanism, including link 86 and member 88, acts on boom 80, and both link 
86 and boom 80 are mounted on swivel 92, that swivel is also held when the 
braking mechanism is engaged to hold boom 80. Housing 10 is dimpled 
adjacent to swivel 92, as shown in FIG. 12, to provide a substantially 
uniform braking surface in all positions of swivel 92. 
When a microphone and tape extension has ended with the microphone in a 
user-selected position, the relaxation of tension in tape 12, as already 
described, releases link 83. Bias spring 89 then drives link 86 clockwise 
to restore braking action of member 88. Excessively forceful wedging of 
member 88 between housing 10 and one of the camming sectors 105 or 106 of 
boom 80 is prevented by a mechanical stop surface 99 on link 86 bearing 
against link 83. 
At the right-hand end of swivel 92 in FIG. 11, the tape 12 extends through 
a passage 98 toward block 27. That passage and the nearby spring 96 are 
also seen in FIG. 13. Between the passage 98 and block 27 the tape 12 can 
be subjected to limited twisting to accommodate rotation of swivel 92. 
Although the present invention has been described in connection with 
particular applications and embodiments thereof, it is to be understood 
that additional applications, embodiments, and modifications which will be 
obvious to those skilled in the art are included within the spirit and 
scope of the invention.