BACKGROUND OF THE INVENTION
1. Field of the Invention
[0001] The present invention generally relates to loudspeakers and loudspeaker suspension
systems, and more particularly, to a loudspeaker and suspension system that separates
the lower suspension from the diaphragm and voice coil with a concentric tube member
to provide a restoring force both above and below the moving assembly's center of
rotation.
2. Description of the Prior Art
[0002] As high-excursion loudspeakers are more commonly used, weaknesses in traditional
loudspeaker suspension are becoming more apparent. When large amounts of cone movement
are required, lateral stability of the moving components (that is, the coil and former)
becomes critically important. This is because clearances between the voice coil and
magnetic gap boundaries are minimal, as seen in the prior art speaker of Fig. 1. Consequently,
any deviation from the desired linear motion (i.e., rocking) can cause the voice coil
to rub against the top plate and/or pole piece. This rubbing can produce unacceptable
levels of audible noise and may even lead to driver failure if the instability is
severe.
[0003] In the typical loudspeaker, one cause of the moving component instability is the
small physical distance between the suspension components, leaving little tolerance
for rocking. The conventional suspension system comprises a roll 3 (outer suspension)
and spider 2 (inner suspension). The roll 3 and spider 2 are the members responsible
for controlling and stabilizing the position of the cone and voice coil relative to
the motor structure. When the moving assembly begins to rotate away from its ideal
linear path during its travel, the roll and spider are called on to resist and prevent
rocking. The roll and spider, however, only have a limited amount of restoring force
available to resist the rocking motion. This limited resistance to rocking is exacerbated
by their close physical proximity to the center of rotation. Being located near the
rotational center does not afford any leverage for augmenting the meager restoring
force of the spider. In addition, the rotation center is volatile, whereby changes
in excursion shift the rotation center, altering moment forces on the roll and spider.
Notwithstanding, the spider remains relatively close to the center of rotation, such
that any mechanical advantage in the typical suspension system is minimized by its
proximal relationship to the axis of rotation.
[0004] High excursion loudspeakers further amplify problems with rocking, as high-excursion
loudspeakers require relatively long voice coil winding lengths. A very significant
portion of the moving assembly's weight consists of the copper wire in the voice coil.
Longer winding lengths dictate that the copper wire in the coil be distributed over
a greater linear distance along the voice coil former's axis. Consequently, more of
the coil's weight is placed further away from the spider, affecting the position of
the rotation center. This increases the pendulum-like behavior of the system and makes
rocking modes harder to control.
[0005] High-excursion loudspeakers often compensate for rocking mode problems by increasing
the width of the magnetic gap in which the voice coil resides. A larger clearance
between the coil and the motor structure allows the speaker to tolerate more movement
of the voice coil without contact. However, there is a downside to increasing the
width of the magnetic gap. A larger magnetic gap decreases the magnetic flux density
in the gap, and hence the driver's motor strength. Decreased power handling capability
is another trade-off when enlarging the gap. This is because the metal parts are now
farther away from the voice coil, making them less effective in transferring heat
away from the coil body. Consequently, heat builds up in the voice coil, causing adhesives
to soften, and creating more power-related failures.
[0006] Conventional high-excursion loudspeakers also require excessive loudspeaker mounting
depth. The important clearance dimensions in a speaker design include the clearance
between the neck joint (intersection of cone, spider, and voice coil former) and top
plate, and between the bottom of the voice coil and the back plate. These clearances
must be greater than or equal to the driver's maximum physical excursion capability.
The speakers with a large cone excursion require a larger corresponding clearance
within the frame structure to prevent moving parts from making contact during peaks.
As the excursion capability increases, so does the depth of the loudspeaker structure.
This problem can be troublesome in certain markets, such as car audio, since consumers
typically desire the placement of very high performance drivers in extremely tight
places.
[0007] Finally, it is also desirous to provide alternative ways to vent air pressure from
under the diaphragm. An air volume defined by the traditional diaphragm, dust cap,
voice coil inner diameter, and pole piece changes size as the loudspeaker's moving
structure travels through its excursion range. If this pressure is not released, the
cone's motion will be impeded, changing the woofer's performance specifications dynamically
depending on excursion. This air pressure is usually vented through a vent machined
in the pole piece. However, machining the vent increases the cost of the motor structure
and can increase magnetic circuit losses due to the removal of metal from the pole.
the instant invention offers several alternate means of venting this air pressure.
[0008] Several speaker designs may be available in the background art for increasing stability.
However, none are known to solve the above-noted problems. In fact, there is no design
known which is directly comparable to the concentric tube concept. Past attempts to
increase the mechanical stability of loudspeakers have generally utilized dual spiders
separated by some predetermined distance. However, any advantage realized in these
designs is limited and offset by the need for an additional spider with little separation
from the first spider. As the above-noted devices neither solves nor adequately addresses
the problems contemplated by the present invention, there remains a need for a loudspeaker
with increased stability and resistance to rocking.
SUMMARY OF THE INVENTION
[0009] An object of the instant invention is to provide a concentric tube suspension system
for loudspeakers to reduce moving assembly rocking in a speaker's magnetic gap and
to provide a stronger joint between the suspension system and moving assembly.
[0010] Another object of the invention is to provide a loudspeaker with a suspension system
that eliminates the diaphragm, spider, and voice coil junction , i.e. neck joint,
as a failure point.
[0011] A further object of the invention is to provide a suspension system for use in loudspeakers
including, but not limited to, high-excursion loudspeakers, for increased linear and
lateral moving assembly stability to reduce rocking.
[0012] It is another object of the invention to provide a suspension system that improves
the mechanical stability in loudspeakers.
[0013] It is a further object of the invention to provide a suspension system that enhances
the glue joint between the lower/spider suspension and the moving assembly.
[0014] It is yet another object of the invention to provide a suspension system that is
adaptable to high-excursion loudspeakers for enhanced moving assembly stability and
speaker performance.
[0015] It is yet an additional object of the invention to increase the separation between
the upper suspension and lower suspension and to separate the lower suspension from
the diaphragm for enhanced leverage.
[0016] It is yet a further object of the invention to separate the lower/spider suspension
from the electromagnetic driver structure.
[0017] It is still another object of the invention to provide a concentric tube stabilizer
that increases separation between the upper/roll and lower/spider suspensions to improve
the loudspeaker's resistance to rocking by maximizing the suspension's leverage over
the moving assembly.
[0018] It is also an object of the invention to make it easier to use an additional spider
while providing larger separation between the spiders and flexibility in diaphragm
selection.
[0019] It is still an additional object to provide a suspension system that facilitates
a loudspeaker with decreased mounting depth.
[0020] In light of these and other objects, the instant invention generally comprises a
concentric tube suspension system for use in loudspeakers to increase resistance to
moving assembly rocking. The loudspeaker generally comprises the new suspension system,
a voice coil including the former and winding, a diaphragm extending from an upper
suspension to the voice coil, a concentric tube stabilizer depending from the diaphragm
to a lower suspension, a frame and an electromagnetic motor structure. The moving
assembly basically includes the voice coil, diaphragm and the suspension system. The
suspension system generally comprises the upper/roll suspension which connects the
upper edge of the diaphragm to the frame and a lower/spider suspension connected at
one end to the lower end of the tube stabilizer and at the other end to the frame.
The tube stabilizer depends downward from the diaphragm so as to be concentric about
the electromagnetic driver structure. The stabilizer may be attached to the diaphragm
by several different means including, but not limited to, adhesives, adhesive impregnated
foam or a ventilation ring. The stabilizer descends to the spider and attaches at
a level substantially below the uppermost surface of the motor structure and at a
level adjacent to the lower portion of the voice coil windings. Thus, the spider attaches
to the outer diameter of the concentric tube stabilizer, and not to the voice coil
former. Accordingly, the suspension system extends vertically across the loudspeaker
to provide support above and below the moving assembly's axis of rotation about which
a speaker's moving assembly tends to rock. This configuration allows drastically improved
mechanical stability and significant reduction in the driver mounting depth.
[0021] The present invention offers several advantages over conventionally designed loudspeakers.
In conventional high excursion speakers, the spider (lower suspension) is often attached
to the voice coil in the vicinity of the static rotational center of the moving structure.
Since the spider is positioned proximal to the rotational center, it must resist twisting
motion in addition to lateral movement. In the instant invention, the suspension system
incorporates a novel concentric tube stabilizer that separates the lower suspension
from the diaphragm and increases the separation between the upper suspension (roll)
and the lower suspension (spider) to provide increased resistance to rocking without
increasing the mounting depth of the loudspeaker. The design of the instant invention
is based in part on the theory that leverage over a rotating body is maximized by
moving suspension components to the ends of the body. This is accomplished by attaching
the spider much farther down the moving assembly to afford greater separation between
the upper/roll suspension and the lower/spider suspension. The increased separation
increases the loudspeaker's linear stability (resistance to rocking) by maximizing
the suspension system's mechanical advantage or leverage over the moving assembly.
This mechanical advantage exists regardless of where the rotational center is located
and can be realized without the use of an exotic spider. Furthermore, since the tube
stabilizer straddles the motor structure, the risk of the spider coming in contact
with the stationary metal parts of the driver is not a concern.
[0022] Another advantage is that the stabilizer does not limit the spider's attachment point
to any one position in relation to the voice coil because it offers a continuous outer
structure. This allows the spider to be attached below the moving assembly's rotational
center at a number of selected points. Thus, the roll and spider in tandem can provide
enhanced resistance to rotational or rocking movement over the moving assembly's excursion.
This optimizes the performance of the suspension system and virtually eliminates rocking
mode problems.
[0023] The instant invention also facilitates the design of loudspeakers having more shallow
depths. Since the spider can be attached at points closer to the back plate of the
speaker, a flat diaphragm or more shallow cone (implying a larger cone angle) may
be used allowing the electromagnetic driver/motor structure to be shifted upward,
closer to the cone apex, into formerly wasted space. The loudspeaker's mounting depth
is therefore drastically reduced for a given roll-spider separation. Loudspeakers
with minimal mounting depth are useful in situations where enclosure space is at a
premium.
[0024] The instant invention also realizes the advantages that result from the use of a
spider suspension having a larger inner diameter. Those advantages include a stronger
glue joint and a more reliable spider suspension. Since the spider is attached to
the tube stabilizer along its interior edge, the circumference of the glue joint is
proportionately increased with a larger inner diameter. A longer glue joint distributes
the stresses along a larger portion of spider material and lowers the demand on the
glue bond, making the spider attachment more reliable. As the inner diameter increases,
the circumference intersects more individual strands of material so that the spider
is less prone to fatigue along the critical glue joint. Moreover, the spider with
a larger inner diameter experiences more material deflection for a given amount of
rocking. As a result the suspension is more resistant to rocking.
[0025] In addition to making the loudspeaker more reliable, greater stability can provide
several other benefits. For instance, in the areas of magnetic design and thermal
power handling, the increased stability allows for tighter magnetic gap tolerances
which provide better thermal transfer and greater magnetic flux density in the gap.
The loudspeaker can also be designed with a reduced mounting depth for use in areas
of limited space without compromising performance. Thus, thinner speaker designs are
possible with the instant invention. The instant invention further provides a loudspeaker
system which reduces the amount of machining in the speaker's motor construction,
whereby it facilitates the incorporation of alternative venting structure.
[0026] In accordance with these and other objects which will become apparent hereinafter,
the instant invention will now be described with particular reference to the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027]
Fig. 1 is a cross sectional view of a prior art loudspeaker.
Fig. 2 is a partial cross sectional view of a prior art speaker aligned with the instant
invention for side-by-side comparison.
Fig. 3 is a cross sectional view of one embodiment of the loudspeaker of the instant
invention.
Fig. 4 is a cross sectional view of another embodiment of the loudspeaker of the instant
invention.
Fig. 5 is a cross sectional view of another embodiment of the invention.
Fig. 6 is a top planar view of one ventilation adaptor ring.
Fig. 7 is a cross sectional view of the adaptor ring taken along line 7-7 of Fig.
6, illustrating the adhesive reservoirs.
Fig. 8 is a cross sectional view of another embodiment of the invention.
Fig. 9a is a cross sectional view of the preferred embodiment of the loudspeaker of
the instant invention illustrating a preferred adaptor ring.
Fig. 9b is a top planar view of the preferred adaptor ring.
Fig. 9c is a cross sectional view of the preferred adaptor taken along line 9c-9c
of Fig. 9b.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0028] With reference to the drawings, Figs. 2-9c depict the loudspeaker 10 of the instant
invention. The loudspeaker 10 generally comprises a moving assembly, an electromagnetic
driver/motor structure 26, 28, 29 for cycling the moving assembly, a novel suspension
system 16, 30, 40 for stabilizing the moving assembly, and a frame 18 to provide overall
structural support for the foregoing. The moving assembly generally comprises a voice
coil 20 and a diaphragm 12, and the voice coil 20 includes a voice coil winding 24
supported by a former 22.
[0029] The loudspeaker 10 provides enhanced performance by incorporating a novel concentric
tube suspension system that minimizes rocking of the speaker moving assembly by maximizing
leverage. Referring to Fig. 3, the instant suspension system generally comprises an
outer continuous tubular cylinder or concentric tube stabilizer 40, an upper/roll
suspension 16, and at least one lower/spider suspension 30. Fig. 2 is divided to represent
the present invention on one side and a conventional loudspeaker on the opposite side.
Distance "A" represents the distance between the roll and the spider for the concentric
tube speaker. Distance "B" represents a smaller distance between the roll and spider
in conventional speakers. Finally, distance "C" illustrates the separation advantage
held by the concentric tube design. With reference to the suspension system of the
instant invention, the upper suspension 16 comprises an arcuate roll attached to the
outer peripheral edge of the diaphragm on an inside edge and to the frame 18 on its
outside edge. The spider 30 comprises a donut-shaped, corrugated, lightweight anchor
or suspender. The stabilizer 40 is attached near its lower end 44 to the spider 30
and at its upper end to the diaphragm 12. The stabilizer 40 eliminates the traditional
neck joint as a stress or failure point and prevents rocking of the moving assembly
as discussed hereto. The tube stabilizer 40 is substantially cylindrical and depends
from the bottom surface 12b of the diaphragm 12 so as to be concentrically positioned
around the electromagnetic motor structure 26 and, hence, voice coil 20. The tube
stabilizer 40 is preferably attached to the diaphragm 12 by an adhesive, such as epoxy,
at a predetermined mid-point for optimal voice coil 20 stability and speaker sound
quality. The lateral position of the tube stabilizer 40 is directly related to the
diameter of the motor structure 26 and depends from the diaphragm bottom surface 12b
so that it straddles the motor 26 structure without making contact.
[0030] Several alternate means for attaching the stabilizer 40 to the diaphragm 12 may be
employed and interchanged between speakers as discussed herein. For instance, with
a cone-like structure, the diaphragm 12 preferably defines a cylindrical elbow 15
by making a substantially downward vertical bend from its usual obtuse plane for a
predetermined length before angling back toward the voice coil 20. The elbow 15 provides
a vertical surface for attaching the tube stabilizer 40 along its interior wall 46
at the upper peripheral edge 42. Accordingly, the cylindrical elbow 15 defines an
outer diameter that is essentially equal to the inner diameter of the tube stabilizer
40, at least at the upper edge 42. An upper stabilizer joint 45 is thus formed at
an elevation above the former neck joint. More importantly, the concentric tube stabilizer
40 separates the spider 30 from the cone 12 and roll providing greater lateral support
in the moving assembly. The separation provided by the tube 40 enhances the reinforcement
and stabilization force of the spider 30 for greater control. This lateral control
is also achieved because the cone and stabilizer act as a rigid body. The stabilizer
40 may also be attached to the diaphragm with an adhesive impregnated foam 50 or a
ventilation adaptor ring 60 as shown in Figs. 4 and 5, respectively.
[0031] Referring to Figs. 2 and 3, the tube stabilizer 40 depends concentrically around
the motor structure 26 at its lower edge 44 below the former neck joint and rotation
axis. The lower suspension or spider 30 preferably attaches to the tube stabilizer
40 proximal its lower edge 44 along its inner diameter edge 32. The spider's inner
diameter 32 is essentially equal to the stabilizer's outer diameter 48, at least along
the lower edge 44 where attached, and is greater than the conventional diameter. A
lower stabilizer joint 47 is formed by the joining of the spider inner diametric edge
32 and the tube stabilizer's outer surface 48. The lower stabilizer joint 47 is positioned
below the former neck joint and axis of rotation as seen in Fig. 2. Since the outer
tubular stabilizer 40 straddles the motor structure 26, the spider's 30 potential
contact with the motor structure is no longer a concern. Consequently, the spider
30 may be attached at a point much farther down on the moving assembly and below the
axis of rotation. This provides greater separation between the upper suspension/roll
16 and the spider 30. The larger separation between the roll 16 and the spider 30
increases the loudspeaker's linear stability and resistance to rocking by maximizing
the suspension's mechanical advantage or leverage over the moving assembly. Thus,
higher excursions are achievable without the risk of unacceptable rocking.
[0032] The mechanical advantages gained by incorporating the tube stabilizer 40 are shown
in Fig. 2. The tube stabilizer 40 essentially elongates the stabilizing force to provide
an increase in the lateral stabilization. As illustrated by separation distance A,
the concentric tube stabilizer 40 moves the lower suspension component (spider 30)
to the lower end of the rotating body (moving assembly) to complement the upper suspension
(roll 16) in maximizing leverage over the system. As shown, the distance A between
the upper suspension and spider in the instant invention is greater than the comparable
distance B in conventional systems. The resulting structural advantage is represented
by C. In addition to the mechanical advantage gained, this design facilitates reduced
mounting depth without compromising performance and tighter magnetic gap tolerances
for improved thermal transfer and increased magnetic flux. In addition, the neck joint
is eliminated as a potential failure point. By contrast, the prior art speaker shown
in Fig. 2 attempts to stabilize the moving assembly at the neck joint proximal to
the axis of rotation. Thus, the prior art suspension system is at a mechanical disadvantage.
[0033] The concentric tube suspension system of the instant invention provides several other
advantages over the prior art. One of the main advantages is that a spider 30 with
a larger inner diameter may be used for securing to the moving assembly. With a larger
inner diameter, the circumference of the inner diametric edge 32 is increased, providing
a longer glue joint. The longer glue joint 47 distributes stress along a larger portion
of the spider 30 material, lowering the demand on the glue bond. This makes the spider
joint 47 attachment much more reliable. In addition, as the inner diameter of the
spider 30 increases, the circumference of the inner diameter intersects more individual
strands of material, making the spider 30 less prone to material fatigue along the
critical inner diameter glue joint 47. Another advantage realized is that a larger
inner diameter spider requires more material deflection for a given amount of rocking
motion. As a result, the suspension provided is more resistant to rocking modes. Moreover,
in addition to making a loudspeaker more reliable, greater stability in the suspension
system can also provide benefits in areas of magnetic design and thermal power handling.
[0034] The tube stabilizer 40 has a continuous structure that allows the spider 30 or additional
spiders to be attached at any one position in relation to the voice coil 20 without
an increase in mounting depth or structure thickness. The stabilizer 40 facilitates
the use of more than one spider 30 to meet design goals. Given the large surface area
of the stabilizer 40, it is simple to use and attach additional spiders 30. Since
a spider 30 attachment can be made much lower on the moving assembly, the spider 30
can be placed on the lower side of the moving assembly's rotational center. Consequently,
the roll 16 and the spider 30 in tandem provide greater resistance to rotational or
rocking movement over the moving assembly's excursion. This optimizes the suspension
system stability and virtually eliminates rocking problems. In an alternative embodiment,
the outer continuous surface 48 of the tube stabilizer 40 may define a peripheral
ledge 49 at a predetermined elevation below the rotational axis for setting and adhering
the spider 30.
[0035] Referring to Fig. 3, the spider's outer diametric edge 34 is attached to the frame
18. A ledge 19 is formed by the frame 18 for setting and adhering the spider edge
34. As the drawings illustrate, the concentric tube stabilizer system allows greater
freedom in diaphragm/cone selection.
[0036] With reference to Figs. 4 and 5, the concentric tube stabilizer 40 facilitates alternative
loudspeaker designs incorporating flatter diaphragms 12 for a more shallow speaker.
By incorporating the concentric tube stabilizer 40, the spider can be attached much
closer to the back of the speaker 10, affording the employment of a flat or shallow
diaphragm 12'. The shallow diaphragm 12' provides a flat or larger cone angle, which
allows the motor 26 to be shifted upward into the speaker near the typical cone apex/neck
joint to minimize wasted space. As a consequence, a loudspeaker's mounting depth is
drastically reduced for a given diaphragm and spider separation. Shallow loudspeakers
provide minimal mounting depth and are very useful in situations where enclosure space
is at a premium. Four embodiments of the shallow speaker design are shown in Figs.
4, 5, 8, and 9a.
[0037] With the shallow speaker design, a composite diaphragm 12' may be employed, as shown
in Figs. 4, 5, and 9a (dual-skin diaphragm may be considered to be a composite). In
the composite diaphragm design, the concentric elbow is eliminated and an alternative
stabilizer attaching means is preferably used. In one embodiment, the concentric tube
stabilizer 40 may be attached to the composite cone 12' by adhesive impregnated foam
50. The impregnated foam 50 comprises a top surface adaptable for attachment to the
diaphragm 12' and a bottom surface which is penetrable by the tube stabilizer 40 for
forming a slit or penetrating a prefabricated slit. This slit is adapted to receive
the stabilizer 40 and adhesives for an enhanced glue joint. The foam 50 may comprise
a plurality of foam strips around the upper stabilizer end 42 and diaphragm or it
may comprise a single annular ring having a central diameter substantially equal to
the stabilizer 40 diameter. The impregnated foam 50 is permanently secured to the
stabilizer's upper edge 42 by filling the slit with a conventional adhesive or epoxy.
The impregnated foam 50 is also adhered to the bottom surface 12b' of the composite
diaphragm 12' with conventional adhesives. The impregnated foam 50 provides a greater
surface area than the stabilizer's upper edge 42 for attaching to the composite diaphragm
12'. The foam 50 may also be used as an attaching means for adhering the stabilizer
to the cone-like diaphragm 12 shown in Fig. 3. Likewise, the voice coil former 22
may be attached to the composite cone 12' with a second adhesive impregnated foam
50. Collectively, the shallow composite cone 12', the impregnated foam 50, and the
suspension system incorporating the concentric stabilizer 40 provide resistance to
rocking and decrease the likelihood of the voice coil 40 rubbing the motor structure
or top plate.
[0038] In another embodiment, the instant invention may incorporate an adaptor ring 60 like
that shown in Fig. 6. The adaptor ring comprises dual concentric rings 62, 64. The
inner concentric ring 64 and outer concentric ring 62 are joined by a plurality of
support ribs 66 that project upward from the rings 62, 64. The ribs 66 have free top
ends which are adhered to the bottom of the diaphragm 12 or 12'. Accordingly, the
ribs' 66 top end should be flat and provide some surface area. Each pair of ribs 66
defines a horizontal and vertical ventilation channel 65b and 65a, respectively, when
the adaptor ring 60 is attached to the composite diaphragm 12'. The ventilation channel
65b provides a pressure relief path from the primary volume defined by the diaphragm
12', the inner diameter of the voice coil 22, and the top plate 29. The secondary
volume defined by the outer diameter of the voice coil 22, the inner diameter of the
concentric tube 40, and the top of the motor pot wall 26 can vent through two paths.
One path is through the vertical vent channel 65a. The second path 27 is defined between
the inner diameter of the concentric tube 40 and the outer diameter of the motor structure.
However, the secondary volume may not be able to vent freely through the second path
27 due to the close proximity of the parts. Pole vents are therefore not required
in the motor structure 28. The adaptor ring 60 may be attached to the composite diaphragm
12' with conventional adhesives or foam.
[0039] The adaptor ring 60 receives and secures both the stabilizer 40 and former 22. With
reference to Fig. 7, the ring 60 comprises a pair of continuous depending annular
tabs 67 which are in tubular relation with either the voice coil former 22 or the
stabilizer 40. Each tab 67 defines an annular trough/reservoir 69 for respectively
receiving the concentric tube stabilizer 40 and the voice coil former 22 in the throat
of the reservoirs 69. Accordingly, the first annular tab 67 projects downwardly from
the outer ring 62 in alignment with the stabilizer 40, while the second annular tab
67 projects downwardly from the inner ring 64 in alignment with the former 22. As
shown in Fig. 5, each reservoir 69 is adapted for receiving an adhesive to adhere
the stabilizer 40 and the former 22, respectively. In the alternative, the tabs 67
may comprise a plurality of discontinuous reservoir troughs, which may or may not
be in alignment with the ribs 66. In either event, the spider suspension 30 attaches
to the stabilizer 40, as previously discussed, to collectively provide the stabilizing
force needed for unencumbered linear travel of the moving assembly.
[0040] With reference to Fig. 8, another loudspeaker embodiment may be employed with the
stabilizer 40 and hence suspension system of the instant invention. In this embodiment,
the stabilizer 40 facilitates the incorporation of an inner cone 12'' and an outer
skin 12' in a loudspeaker configuration. The inner cone 12'' defines a raised section
at its upper corner which sharply angles downward at its apex toward the stabilizer's
lower end 44. The lower end 44 is structurally adapted for simultaneously attaching
the inner cone 12'' and the spider 30 along its inner edge 32. The outer skin 12'
bridges across the inner cone. The outer edge of both the outer skin 12' and inner
cone are attached to the roll. This embodiment provides the benefits of a deeper cone
diaphragm without the drawbacks of having to connect the cone to the voice coil former
22. Rather, the stabilizer 40 secures the cone 12'' with a stronger more reliable
attachment than that provided by the voice coil former. The upper end 42 of the stabilizer
40 may be attached to the outer skin 12' by any of the attaching means discussed herein.
[0041] Still referring to Fig. 8, the stabilizer 40 and former 22, in this embodiment, may
define a plurality of apertures, openings, or vents 41 for releasing air pressure
in the former volume. The vents 41 provide a path to ambient. It should be noted that
a pole vent in the motor structure may be alternatively employed. Ventilation vents
may also be defined by the impregnated foam 50 or by voids defined by strips of foam
50. If the foam 50 is continuous, it would include vent passages 41. On the other
hand, discontinuous foam 50 would define open space between the strips 52 to vent
air pressure.
[0042] In the preferred embodiment, the adaptor ring may comprise a substantially conical,
truncated, vented ring 70, as shown in Figs. 9a-9c for use with a cone structure 12''
as shown in Fig. 9a and similar to that shown in Fig. 8. The preferred adaptor ring
70 is substantially cone-shaped with a truncated/flat top surface 74. The alternative
adaptor ring 70 essentially comprises an upper ring 72, an inner annular trough 77,
and an outer annular trough 78, all of which are periodically joined and secured by
a plurality of ribs 76. The upper ring 72 defines the truncated/flat surface 74 and
has sufficient thickness and a plurality of periodic depending feet for reinforcement
and stability. The top surface 74 is adhered to the cone diaphragm 12'' by conventional
means. The troughs 77, 78 comprise annular sleeves, each of which define an outer
flange to which the ribs 76 are joined. The inner trough 77 forms a reservoir 79 which
is in alignment with and receives and adheres the former 22. The outer trough 78 defines
a reservoir 79 for receiving and adhering the stabilizer 40. The ribs 76 hold the
annular members 72, 77, and 78 in place and help to define venting channels 75 for
removing air pressure buildup between the diaphragm, the voice coil ID, and the top
plate. The top edge of each rib 76 is recessed below the cone 12'' so that only the
upper ring 72 and upper surface of the outer trough 78a are adhered to the cone. The
trough upper surface 78a preferably defines a contour that complements secured attachment
of the cone 12''. The adaptor ring 70 provides another way of venting heat compared
to the adaptor ring 60 discussed above. Air is vented through the path or passage
75 when the cone moves downward. Air exits through the inner radial opening over the
former 22 and inner trough 77 and out between the motor outer diameter and stabilizer
40. This movement of air aids in cooling by passing over a larger surface area of
the motor for enhanced heat exchange. The adaptor rings 60, 70 are preferably manufactured
by an injection molded plastic.
[0043] The concentric tube stabilizer may be manufactured from paper, craft paper, or Nomex™.
The concentric tube stabilizer thus defines a paper-like tube, adaptable for attachment
to the cone by the attaching means described herein. In the alternative, the concentric
tube stabilizer 40 may comprise a plastic, injection-molded structure for attaching
the diaphragm and spider. An injection molded part makes many additional variations
in spider/cone attachment and pressure ventilation possible while enhancing component
rigidity. Because the injection molding process will allow one to shape the stabilizer
40 as desired, there is greater flexibility in the design of the stabilizer 40, such
as venting options.
[0044] The instant invention has been shown and described herein in what is considered to
be the most practical and preferred embodiment. It is recognized, however, that departures
may be made therefrom within the scope of the invention and that obvious modifications
will occur to a person skilled in the art.
1. A loudspeaker suspension device for stabilizing a moving assembly in a loudspeaker
having an upper suspension and an electromagnetic motor for actuating the moving assembly,
the moving assembly comprising a lower suspension, an upper suspension, voice coil
including a former and winding, and a diaphragm, said moving assembly having an inherent
rotational axis about which rocking can occur, said suspension device for increasing
lateral stability in the moving assembly, said suspension device comprising:
a tubular stabilizer comprising a tube having a predetermined length from an upper
end to a lower end, said stabilizer depending downward from the diaphragm so as to
be concentrically disposed around the voice coil and at least a portion of an electromagnetic
motor of the loudspeaker;
said upper end being attached to the diaphragm and said lower end depending below
the moving assembly's rotational axis, the lower suspension being attached to said
stabilizer below the rotational axis, said stabilizer facilitating increased lateral
stability in the moving assembly; and
means for attaching said tubular stabilizer to the diaphragm.
2. A suspension device as recited in claim 1, further comprising:
ventilation means, defined by said attaching means, for removing air pressure trapped
between the diaphragm and motor.
3. A suspension device as recited in claim 1, wherein said upper end is attached to the
diaphragm at a preselected point, said preselected point defining a bend in the diaphragm.
4. A suspension device as recited in claim 3, wherein said bend is attached to an interior
wall of said tubular stabilizer.
5. A suspension device as recited in claim 1, wherein said tubular stabilizer is substantially
cylindrical, said stabilizer having a continuous outer wall.
6. A suspension device as recited in claim 1, wherein said tubular stabilizer is attached
to the diaphragm and the spider with an adhesive.
7. A suspension device as recited in claim 1, wherein the spider is attached to said
tubular stabilizer at a preselected point proximal said lower end.
8. A suspension device as recited in claim 1, wherein said tubular stabilizer defines
an outwardly projecting ledge for receiving and attaching the lower suspension.
9. A suspension device as recited in claim 1, wherein said attaching means comprises
an impregnated foam adhered at one end to said tubular stabilizer and adhered at an
opposite end to the diaphragm.
10. A suspension device as recited in claim 1, wherein said attaching means comprises
an annular adaptor ring having a ventilation means for removing air trapped between
the diaphragm and motor, said ring having a top surface adhered to the diaphragm,
said ring comprising at least one downwardly projecting reservoir for receiving said
tubular stabilizer, said reservoir being adapted for receiving an adhesive to adhere
said tubular stabilizer in said reservoir.
11. A loudspeaker suspension system for laterally stabilizing a loudspeaker's moving assembly
to prevent undesirable rocking about a volatile rotational axis, wherein the moving
assembly comprises a diaphragm and a voice coil, the voice coil including a former
and voice coil winding, said suspension system comprising:
a tubular stabilizer comprising a substantially cylindrical tube having a predetermined
length from an upper end to a lower end, said stabilizer depending downward from the
diaphragm so as to be concentrically disposed around the voice coil and at least a
portion of an electromagnetic motor of the loudspeaker;
a lower suspension attached to said stabilizer proximal said lower end and below the
moving assembly's volatile rotational axis; and
means for attaching said upper end to the diaphragm.
12. A suspension device as recited in claim 11, further comprising:
ventilation means, defined by said attaching means, for removing air pressure trapped
between the diaphragm and motor.
13. A suspension system as recited in claim 11, wherein said attaching means comprises
an adhesive for adhering said upper end to the diaphragm at a preselected point.
14. A suspension system as recited in claim 11, wherein said attaching means comprises
a downward bend defined by said diaphragm, said bend depending vertically for a predetermined
length, said upper end being concentrically adhered to said bend.
15. A suspension system as recited in claim 11, wherein said attaching means comprises
at least one strip of an impregnated foam, said impregnated foam having a penetrable
bottom surface adapted for securely receiving and adhering said tubular stabilizer
upper end with an adhesive, said foam having a top surface adhered to the diaphragm,
said impregnated foam having a predetermined length.
16. A suspension system as recited in claim 15, wherein said strip substantially forms
a ring depending downward from the diaphragm.
17. A suspension system as recited in claim 15, wherein said impregnated foam defines
a slit for receiving and adhering said upper end of said tubular stabilizer.
18. A suspension system as recited in claim 15, further comprising means for securing
the voice coil former to the diaphragm, said securing means comprising at least one
strip of an impregnated foam, said impregnated foam having a penetrable bottom surface
adapted for securely receiving and adhering an upper end of the voice coil former,
said securing strip having a predetermined length, said securing strip having a top
surface adhered to the diaphragm.
19. A suspension device as recited in claim 11, wherein said attaching means comprises
an annular adaptor ring having a ventilation means for removing air trapped between
the diaphragm and motor, said ring having a top surface adhered to the diaphragm,
said ring comprising at least one downwardly projecting reservoir for receiving said
tubular stabilizer, said reservoir being adapted for receiving an adhesive to adhere
said tubular stabilizer in said reservoir.
20. A loudspeaker comprising:
a moving assembly comprising a diaphragm supported by a frame and a voice coil including
a former and a voice coil winding supported by said former;
an electromagnetic driver for driving said moving assembly, said driver and voice
coil defining a magnetic gap; and
suspension system for laterally stabilizing and centering said voice coil in said
magnetic gap as said voice coil is linearly displaced during operation, said suspension
system comprising:
a tubular stabilizer defining a substantially cylindrical tube having a predetermined
length from an upper end to a lower end, said stabilizer depending downward from said
diaphragm so as to be concentrically disposed around said voice coil and at least
a portion of said electromagnetic motor;
a lower suspension attached to said stabilizer proximal said lower end and below an
inherent volatile rotational axis defined by said moving assembly; and
means for attaching said upper end to said diaphragm;
21. A loudspeaker as recited in claim 20, wherein said attaching means comprises an adhesive
for adhering said upper end to the diaphragm at a preselected point.
22. A loudspeaker as recited in claim 20, wherein said attaching means comprises a downward
bend concentrically defined by said diaphragm, said bend depending vertically for
a predetermined length, said upper end being concentrically adhered to said bend.
23. A loudspeaker as recited in claim 20, wherein said attaching means comprises at least
one strip of an impregnated foam, said impregnated foam having a penetrable bottom
surface adapted for securely receiving and adhering said tubular stabilizer upper
end with an adhesive, said foam having a top surface adhered to the diaphragm, said
impregnated foam having a predetermined length.
24. A loudspeaker as recited in claim 23, wherein said strip substantially forms a ring
depending downward from the diaphragm.
25. A loudspeaker as recited in claim 23, wherein said impregnated foam defines a slit
for receiving and adhering said upper end of said tubular stabilizer.
26. A loudspeaker as recited in claim 23, further comprising means for securing the voice
coil former to the diaphragm, said securing means comprising at least one strip of
an impregnated foam, said impregnated foam having a penetrable bottom surface adapted
for securely receiving and adhering an upper end of the voice coil former, said securing
strip having a predetermined length, said securing strip having a top surface adhered
to the diaphragm.
27. A loudspeaker as recited in claim 26, wherein said securing strip substantially forms
a ring.
28. A suspension device as recited in claim 20, wherein said attaching means comprises
an annular adaptor ring having a ventilation means for removing air trapped between
the diaphragm and motor, said ring having a top surface adhered to the diaphragm,
said ring comprising at least one downwardly projecting reservoir for receiving said
tubular stabilizer, said reservoir being adapted for receiving an adhesive to adhere
said tubular stabilizer in said reservoir.
29. A suspension system as recited in claim 28, further comprising means for securing
the voice coil former to the diaphragm, said securing means comprising a second plurality
of tabs depending downward from said ring inward from said downwardly projecting tabs,
each of said second tabs defining a former reservoir for receiving said former, said
former reservoirs being adapted for receiving an adhesive to adhere said former in
said former reservoirs.