U.S. patent number 3,680,936 [Application Number 05/016,708] was granted by the patent office on 1972-08-01 for stereo sound reproduction system.
Invention is credited to Peter Heinz Backhaus.
United States Patent |
3,680,936 |
Backhaus |
August 1, 1972 |
STEREO SOUND REPRODUCTION SYSTEM
Abstract
This specification describes a stereo sound reproduction system
in which the speakers are mounted separately from the main cabinet,
the cabinet being provided with recesses for storage of the
speakers when not in use, and being further provided with linkage
means connected between the cabinet and the speakers which is
extendable and retractable by means of which the speakers may be
moved away from the cabinet, while remaining supported on the
linkage, and further describes such a system in which the while
remaining supported on the linkage, and further describes such a
system linkage is power operated and may be provided with movement
limiting means whereby a predetermined amount of speaker movement
may be preselected, and the speakers moved out to such a position
by merely pressing a switch.
Inventors: |
Backhaus; Peter Heinz
(Markdale, Ontario, CA) |
Family
ID: |
26688970 |
Appl.
No.: |
05/016,708 |
Filed: |
March 5, 1970 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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691352 |
Dec 18, 1967 |
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Current U.S.
Class: |
312/7.1; 181/145;
181/147; 312/8.16 |
Current CPC
Class: |
A47B
81/065 (20130101); A47B 46/00 (20130101); A47B
81/062 (20130101) |
Current International
Class: |
A47B
81/00 (20060101); A47B 46/00 (20060101); A47B
81/06 (20060101); A47b 081/06 () |
Field of
Search: |
;312/7,8,29,223
;181/31.1B ;274/2 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Mitchell; James C.
Parent Case Text
This invention relates to a cabinet for use with a stereo sound
reproduction system and to such a system in which the speakers are
movably mounted and are extensible outwardly to improve the stereo
effect, and is a continuation-in-part of application Ser. No.
691,352, entitled Stereo Sound Reproduction System, filed Dec. 18,
1967 now abandoned.
Claims
What I claim is:
1. Stereo sound reproduction apparatus of the type having at least
two speakers and sound reproduction channel means connected
thereto, said apparatus comprising;
main cabinet means having symmetrical front and back panel means of
equal length, and two ends;
speaker unit recesses formed within the interior of said main
cabinet means at each end thereof between said front and back panel
means;
openings in said ends of said cabinet means giving access to said
speaker unit recesses, said openings being concealed from the front
of said main cabinet means by said front panel means;
two speaker units having outer and inner ends shaped and
dimensioned to fit within the interior of said main cabinet means
between said front and back panel means in respective said recesses
and being movable relative to said main cabinet means between at
least partially extended and retracted positions without disturbing
said front panel means, said speaker units when in said retracted
position being substantially concealed by said front panel means
with said outer ends of said speaker units closing said end
openings, and said two speaker units being connected to said sound
reproduction channel means, and,
movable speaker unit support means connected between said main
cabinet means and said speaker units, said support means being
adapted to permit at least partial extension and retraction of said
speaker units as aforesaid with respect to said main cabinet means
whereby to permit movement of said speaker units out of and into
respective recesses in said main cabinet means, without disturbing
said front panel means.
2. Stereo sound reproduction apparatus as claimed in claim 1
including motion transmission means connected to respective said
speaker units and power operated drive means for driving said
motion transmission means.
3. Stereo sound reproduction apparatus as claimed in claim 1
including movement limiting means associated with said support
means, said limiting means controlling the extension of said
speaker units.
4. Stereo sound reproduction apparatus as claimed in claim 1
wherein said speaker units are dimensioned to fit snugly within
said recesses, and said support means is offset relative to said
units within said recesses thereby leaving same clear for
substantially complete retraction of said speaker units into said
recesses.
5. Stereo sound reproduction apparatus as claimed in claim 1
wherein said main cabinet means is of generally rectangular
box-like construction having top and bottom wall means, and back
and front wall means;
and including inner wall means extending at least partially between
said top and bottom walls spaced inwardly from said ends and
defining said speaker unit recesses between said inner wall means
and portions of said front and back wall means and said top and
bottom wall means, and
shelf means located in said main cabinet means between said inner
wall means for supporting at least in part said sound reproduction
means therein.
6. Stereo sound reproduction apparatus as claimed in claim 1
wherein said main cabinet is of generally rectangular box
construction having top and bottom wall means, and a front and back
wall means;
partition means extending at least partially between said top and
bottom wall means spaced between said front and back wall means and
defining speaker recesses on one side thereof corresponding
substantially in height and width to the dimensions of said speaker
units;
said openings in said ends of said main cabinet giving access to
said speaker recesses and dimensioned to receive said speaker units
therethrough, thereby permitting extension and retraction of said
speaker units therethrough, thereby permitting extension and
retraction of said speaker units with respect to said speaker unit
recesses;
intermediate wall members defining a spacing therebetween extending
at least partially between said top and bottom walls lying in
planes parallel to but spaced inwardly from said ends and forming
inner walls of said recesses; and,
shelf means located in said main cabinet means for supporting at
least part of said sound reproduction means therein.
7. Stereo sound reproduction apparatus as claimed in claim 1
including end wall means on each said speaker unit shaped and
dimensioned to close its respective said openings in respective
said ends of said main cabinet when said speaker units are in their
retracted position.
8. Stereo sound reproduction apparatus as claimed in claim 1
including hinge means mounted between a corner of each said speaker
unit, and said main cabinet pivotally mounting said speaker units
for pivotal movement about vertical axes relative to said main
cabinet into and out of said speaker recesses.
9. Stereo sound reproduction apparatus as claimed in claim 1
including linkage means pivotally mounted on said speaker units,
and electrical drive means operatively connected to said linkage
means to swing said speaker units between said extended and
retracted position.
10. Stereo sound reproduction apparatus as claimed in claim 1
wherein said speaker units are swingably mounted on said main
cabinet for swinging into and out of said recess.
Description
It is well known that in order to produce a satisfactory stereo
effect from a stereo sound reproduction system, that a certain
predetermined spacing of the speakers is required in order that the
listeners, sitting at a given distance from the speakers, may be
located at the "focal" distance from the speakers. Obviously, the
spacing of the speakers will be to a large extent dependent upon
the distance at which the listeners sit with regard to the
speakers. In many stereo systems, it is in fact necessary for the
listeners to move their chairs about the room in order to locate
the point of greatest stereo effect. In cases where the stereo
speakers are all incorporated within a single cabinet, it may be
necessary to sit uncomfortably close to the stereo cabinet.
Alternatively, in cases where the speakers are incorporated in
separate cabinets, it becomes difficult to provide an overall
pleasing arrangement of the furniture in the room in which three
separate pieces of sound reproducing equipment must be arranged in
position which appear both aesthetically pleasing to the eye, and
are also effective in use. The problem become more aggravated when
it is attempted to design more compact stereo cabinets in which the
separation of the speakers is even less.
One attempt to overcome this problem has been the provision of
speakers which are incorporated in separate speaker cabinets, the
speaker cabinets being hinged to the main central cabinet, housing
the sound reproducing circuits and control, the speaker cabinets
being normally folded inwardly in front of the main cabinet for
storage, and being foldable outwardly for use. This solution has
provided quite popular in the past, particularly in the case of
compact stereo units such as for example so called portable units,
but has not been satisfactory for larger units due to the greater
depth of speaker cabinet required for higher quality sound
reproduction.
It is therefore apparent that in order to provide a satisfactory
stereo cabinet, it is necessary to incorporate, in a stereo cabinet
of a relatively compact and pleasing design, a means for arranging
for a greater separation of the speakers than can be accommodated
by the cabinet itself, and at the same time arranging for means for
concealing the speakers within the stereo cabinet when not in
use.
When it is attempted to provide a movable spacing for the speakers
in relation to the central cabinet however, especially in the
higher priced stereo unit having a higher power output, new
problems arise. Thus, it is well known that the speakers must be
arranged in speaker cabinets of certain predetermined engineered
dimensions, the speaker cabinets being required to provide an
enclosed volume of a certain predetermined depth behind the
speakers, and height, in order to permit the speakers to operate
free of distortion. Thus speaker cabinets are usually made of
relatively thick heavy wooden material such that it will permit the
construction of speaker cabinets of substantial size while
remaining relatively rigid. Obviously, any attempt to make such
speaker cabinets movable will require that the movement mechanism
will operate satisfactorily notwithstanding the great weight of the
speakers and speaker cabinets. In addition, when the speakers are
operating at full power, considerable vibration occurs, and any
slackness in the speaker cabinet mounting means will permit the
speaker cabinet to shake in response to such vibration thereby
impairing the quality of the sound reproduction, and also
shortening the life of the relatively expensive speakers.
In addition, it is considered desirable, although not absolutely
essential, to provide means in the stereo unit of remote control
for the speaker spacing, and means for presetting the degree of
spacing on controls on the stereo unit so that once a particularly
suitable spacing is determined by trial and error, the same spacing
can readily be achieved at any time in the future without further
experimentation.
A further feature which is considered desirable in a high class
stereo unit is the fact that the exterior appearance of the stereo
unit, when not in use, should be that of a particularly pleasing
piece of furniture giving an air of quality and distinction to its
surroundings, and in which the speakers are completely concealed.
At the same time, it is also desirable that the cabinet should
provide means for storing records and reels of tape in a manner
providing for easy access and sorting, preferably being located at
the front of the cabinet.
It is therefore an objective of the invention to provide a stereo
cabinet having speakers which are arranged in housings or speaker
cabinets which are themselves located normally in a stored position
within the stereo cabinet, and which may be extended from such
cabinet for use, and in which such extension may be power operated,
while providing a stereo cabinet having an overall pleasing
aesthetic appearance, and also providing individual speaker
cabinets of adequate size and particularly of adequate depth behind
the speakers themselves, so as to provide for efficient development
of sound waves from such speakers.
More particularly, it is an objective of the invention to provide a
stereo cabinet having the foregoing advantages which is provided
with a pleasing aesthetic frontal appearance, and is further
provided at each end with recesses for speaker cabinets, the
speaker cabinets being normally accommodated within such recesses
in retracted positions when not in use, and being extensible from
such recesses outwardly of the stereo cabinet for use.
More particularly, it is an objective of the invention to provide a
stereo cabinet having the foregoing advantages in which the speaker
cabinets are mounted on rail means, such rail means being adapted
to be extended outwardly from such cabinet be means of extension
and retraction mechanism contained within the cabinet and
controlled from the cabinet itself.
More particularly, it is an objective of the present invention to
provide a stereo cabinet having the foregoing advantages in which
the speaker cabinets, even when located in their positions of
maximum extension, are fully supported against tilting or angling
downwardly, and are rigidly supported by such extension mechanism
in a manner resistant to vibrations developed even when operated at
full power.
It is a further and related objective of the invention to provide a
stereo cabinet having speaker cabinet recesses at each end of the
speaker thereby providing concealed storage for the speakers when
not in use, and having record storage recesses arranged down the
front of the cabinet, where the speakers are normally located in a
conventional cabinet, and in which the major portion of the space
between the two speaker recesses throughout the full depth of the
cabinet, is made available for installation of the turn table,
amplifier, and tape recorder equipment.
The foregoing and other advantages will become apparent from the
following description of a preferred embodiment of the invention
which is given here by way of example only with reference to the
following drawings in which like reference devices refer the like
parts thereof throughout the various views and diagrams and in
which;
FIG. 1 is a perspective illustration of a speaker cabinet according
to the invention partially cut away to reveal the construction
thereof showing the speakers in their extended position;
FIG. 2 is a schematic perspective illustration of the mechanism for
extending and retracting the speakers, and showing the outline of
the speaker cabinets in phantom;
FIG. 3 is a plan view of the space of the speaker cabinet shown in
FIGS. 1 and 2 showing the layout of the extension and retraction
mechanism;
FIG. 4 is a section along the line 4--4 of FIG. 3;
FIG. 5 is a section along the line 5--5 of FIG. 2 showing the
details of the upper portion of the extension and retraction
mechanism;
FIG. 6 is a sectional end elevation along the line 6--6 of FIG.
1;
FIG. 7 is a schematic top plan view of a further embodiment of the
invention according to a modification of the invention with the
speaker cabinet shown in phantom, and,
FIG. 8 is a schematic top plan view of a further embodiment with
part of the speaker cabinet itself shown in phantom, and showing a
further modification of the embodiment of FIG. 7.
Turning now to FIG. 1 it will be seen that this preferred
embodiment of the invention comprises a central stationary stereo
cabinet indicated generally as 10 provided with two speaker
cabinets indicated as 11 movably mounted by means to be described
below, for extension and retraction relative to the cabinet 10.
The cabinet 10 will be seen to be of generally rectangular box like
construction having a base 12, a top 13, a back 14 and end wall 15.
Bi-fold doors indicated generally as 16 are provided for closing
the front of the cabinet and providing a pleasing appearance. The
interior of the cabinet 10 will be seen to be divided by partitions
17 extending from front to rear of the cabinet 10, into right and
left hand compartments indicated as references R and L and a
central compartment indicated as reference C. Right and left hand
compartments are of the same design being merely complementary to
one another, and accordingly the left hand compartment L is
illustrated for the sake of clarity. The compartment L will be seen
to be divided by a vertical partition 18 into a rearward speaker
storage compartment indicated by the reference S and forward record
storage compartment provided with shelves 19 and horizontally
hinged doors 20 provided with a suitable check mechanism (not
shown) of conventional design for holding the doors 20 in a
partially open position thereby permitting records stored on
shelves 19 to be readily examined in order to select a particular
record for playing, the open door 20 providing an outwardly angled
support for such records during sorting.
The central control compartment C is provided with shelves
indicated as 21, extending horizontally from front to back of
cabinet 10. The space between the upper shelf 21 and the top 13 of
the cabinet is further divided by a vertical partition 22, the
front half of upper shelf 21 being available for support of control
mechanism such as receiver A. The remaining two shelves 21 define
zones extending the full depth of the cabinet 10 for supporting
stereo reproduction means such as phonograph P and tape recorder T.
The space between the lower most shelf 21 and the base 12 of the
cabinet is divided by a partition 23 extending vertically
therealong and is provided with a further horizontally hinged door
24 for storage purposes.
From FIG. 1 and FIG. 6 it will be noted that the extension and
retraction mechanism for the speakers is fastened to the base 12
and the top 13 of the cabinet and extends along the interior of
speaker zone S and through partitions 17, openings 25 being
provided therethrough for the purpose. The spaces in central
compartment C lying behind partition 22 and 23 are thereby made
available for such extension and retraction mechanism in a manner
to be described below.
The extension and retraction mechanism is described with particular
reference to FIGS. 2, 3, 4, and 5. The principal support function
for speaker cabinet 11 is provided by the lower bars 30 which are
of relatively massive construction and are provided with a section
which is a combined T section and channel section thereby providing
a maximum of strength and rigidity both in the vertical and
horizontal plane. In this way, each of the bars 30 provide a lower
horizontally oriented channel and two upper vertically oriented
channels for purposes to be described below. It will be noted that
each speaker cabinet 11 is provided with a separate bar 30 and for
the sake of clarity, only one such cabinet and bar will be
described, it being understood that the arrangement for the
opposite speaker 11 is essentially complimentary, with only minor
differences which will be pointed out later. The outer end of the
bar 30 is screwed to the interior of the speaker cabinet 11 by
recess headed screws (not shown) passing through the upper T
portion of the bar 30, thereby leaving the lower channel portion
free for movement. That portion of the bar 30 which would normally
be visible between the speaker cabinet 11 and the central cabinet
10 when the speaker cabinet 11 is in its fully extended position,
is concealed by means of the channel shaped sleeve 31 fitting
therearound, sleeve 31 being dimensioned so as to pass at least
partially through opening 25 in cabinet partition 17. In order to
support bar 30 for axial sliding movement in and out of cabinet 10,
there is provided, according to the invention, roller support means
providing support both in the vertical and in the horizontal plane.
Such roller support means in this preferred embodiment of the
invention are arranged in two spaced apart locations to one side of
the center of the cabinet 10, one such support means lying toward
the outer edge thereof and the other such support means being
located closer to the center of the cabinet. Each such support
means comprises a pair of right angle flange members 32 screwed to
the cabinet bottom 12 by means of screws 33 and provided with a
pair of self lubricating plastic rollers 34 which are formed with a
diameter making a good snug fit with bar 30, the rollers 34 fitting
between the upper portion of the T and the transverse portion of
the channel of bar 30 as shown. The rollers 34 therefore provide
the vertical support required, and a certain degree of the
horizontal support as well. The spacing of flanges 32 is preferably
such that the sleeve 31 may pass around the outside thereof thereby
concealing the outer most pair of flanges 32 from view when the
speaker cabinet 11 are in their extended position. In order to
increase the degree of horizontal control of bars 30, a further
pair of rollers 35 is provided between flanges 32 dimensioned to
fit snugly within the lower channel of bar 30. In order to provide
for maximum mechanical advantage of the support system, in relation
to speaker cabinet 11, each of bars 30 extend almost the full width
of cabinet 10, and is fully extended according to this preferred
embodiment, when its free end is at approximately the center of the
cabinet. Thus, given a central cabinet 10 of an approximate width
of 5 feet, it is possible according to this embodiment of the
invention, to obtain a maximum speaker extension on each side of
the cabinet 10 of 21/2 feet, thereby giving a maximum speaker
spacing of 10 feet overall, which is regarded as sufficient for
most high quality stereo reproduction in even quite large
rooms.
It will be understood however, that the maximum spacing described
in connection with this preferred embodiment of the invention is
not in fact critical, and with relatively minor modifications of
the mechanism, much greater extensions can be obtained, and the
invention does not exclude the possibility of providing for a
telescopic extension mechanism (not shown) of any suitable type,
such as is used for example, for the support of heavy drawers,
where very much greater speaker extensions are required.
The upper portion of the extension and retraction mechanism
comprises a relatively light gauge channel bar member 36 the outer
end of which is screwed to the interior of speaker cabinet 11, and
which is provided with a sleeve member 37 fitting therearound,
sleeve member 37 preferably being substantially wider than bar 36
for purposes to be described hereinafter. At the inner free end of
bar 36 and sleeve 37, four rollers 38 are fastened to the upper
surface thereof in a common horizontal plane being clear of
obstruction with bar 36 and sleeve 37. A channel shaped guide way
39 is fastened to top 13 of cabinet 10, being of a depth
substantially equal to the thickness of rollers 38 and making a
good snug fit therearound thereby permitting smooth rolling action
therefore while controlling the movement thereof. Sleeve 37 is
preferably dimensioned so as to pass through opening 25 in
partition 17 of cabinet 10 to permit the speaker cabinet 11 to be
fully retracted therewithin.
Any suitable stop means, such as the moulded edge 14 of cabinet 10
may serve to provide a means of checking the outward extension of
cabinet 11 at their predetermined maximum desired spacing.
The mechanism described above serves adequately to provide
extension and retraction means for the cabinet 11 and provides
rigid support for the cabinet 11 even in their fully extended
position. Obviously, the cabinets 11 may be drawn outwardly to
their extended position and retracted once more by hand, and if
this is the intended mode of operation, any suitable concealed
handhold (not shown) arranged on the rear of the speaker cabinets
11 should preferably be provided in order to obtain a grasp of the
speakers 11 when they are in their fully retracted position. Thus
according to one embodiment of the invention, the invention
contemplates the provision merely of a stationary central cabinet
having speaker cabinet recesses provided at each end thereof and a
speaker extension and retraction mechanism extending at least
across the width of such recesses within said cabinet, said
recesses being equal to the depth of the speaker cabinet, and being
provided at each end of the speaker cabinet so as to permit a
cabinet to be made in which the entire front of the cabinet is made
available for use either for the location of the various
reproduction systems, or for storage, and is not broken up by the
need to locate the speakers themselves therein. However, the
invention is not limited to such embodiment, but also comprehends
the provision of any suitable mechanical or electrical or other
power operated means for causing simultaneous extension and
retraction of the speakers upon the operation of suitable controls,
and also comprehends the provision of additional controls for
preselecting a certain predetermined spacing which may obviously
vary depending upon the number and location of listeners within the
room, and then merely pressing the operating switch to cause the
speakers to be extended to such predetermined position. Obviously,
still further controls may be provided, which may be incorporated
for automatic operation coupled with the circuits in the sound
reproduction system so that as soon as the sound reproduction
system is switched on, the cabinets also are extended, or for
example by a remote control mechanism so that the spacing may be
varied by a listener without moving from his chair.
Thus there is provided, according to this preferred embodiment of
the invention, electrical extension and retraction means comprising
two separate electrical motors indicated as 50 and 51, motor 51
being wound for reverse operation with respect to motor 50, and
both motors 50 and 51 being mounted upon a common drive shaft 52
which in turn is connected to gear box 53, motors 50 and 51 and
gear box 53 being formed into a single integral unit, and attached
by four mounting bolts 54 to mounting plate 55 attached to base 12
of cabinet 10 by means of screws 56. Immediately beneath plate 55,
base 12 of cabinet 10 is cut away to provide a slotted opening
indicated generally as 57, and a gear box output shaft (not shown)
extends downwardly from gear box 53 into such slotted opening 57,
and drives a sprocket and chain (not shown), which in turn drives
sprocket 61 attached to shaft 62 extending through a bearing means
in plate 55 and driving at its upper end pulley wheel 63. A further
free running pulley wheel 64 is provided at one end of cabinet 10
in the speaker cabinet opening indicated as S, free running or
idler pulley 64 being preferably attached to one of flange members
32. A flexible belt 65 extends around pulleys 63 and 64, belt 65 in
fact comprising two similar halves linked together at each end at
plates 66 and screws 67 to form a continuous loop.
It will be noted, that in this preferred embodiment of the
invention, bars 30 are each of a length substantially equal to the
total width of cabinet 10, and are arranged off set side by side
with respect to one another in order that they may move freely in
and out of their respective sides of cabinet 10 without obstructing
one another. Obviously, however this particular expedient is not
regarded as limiting with regard to the invention, and bars 30 of
complimentary mating section sliding one within the other would be
one alternative and bars 30 could similarly be mounted one above
the other, without in any way altering the inventive concept. The
movement of bars 30 outwardly, simultaneously and the simultaneous
retraction thereof, is achieved according to this preferred
embodiment of the invention, by fastening belt 65 at plates 66 and
screws 67 directly to bars 30 at spaced apart locations, adjacent
to pulleys 63 and 64, assuming bars 30 to be in their fully
retracted position, thereby permitting belt 65 to move along a
limited path corresponding to somewhat less than one-half of its
complete length. Obviously, if some greater extension of bars 30
were required, some other expedient should preferably be employed,
such as spacing pulleys 63 and 64 further apart, or resorting to
some different expedient such as a jack screw, or a pair of rubber
frictional drive pulleys bearing directly on bars 30 (not shown)
any of which would permit substantially greater extension than the
mechanism presently illustrated. The purpose of employing two
motors 50 and 51 is of course merely to simplify the controls and
circuits required to produce both extension and retraction, other
expedients being capable of eliminating one of such motors if
desired, which will be obvious to those skilled in the art.
In order to provide positive limiting of the extension of speakers
11 in any desired predetermined location, all that is required is
to provide a simple limit switch device in circuit with electrical
motors 50 and 51 actuated by the movement of speaker cabinets 11.
Thus, according to this preferred embodiment of the invention there
is provided a slide means 70, a sliding shaft member 71, operated
by indicator arm 72 extending through the front of cabinet 10. A
micro-switch 73 is mounted at one end of sliding member 71 and is
oriented to be actuated by cam 74 mounted upon upper sleeve member
37. Any suitable on-off control switch 75 may be suitably located
on the front of the cabinet 10 and connected by circuits (not
shown) or on off control of motors 50 and 51.
As noted above, the sleeve 37, and also the sleeve 31, covering
respective upper and lower bar members 36 and 30, will be seen to
be offset with respect to their respective said bars. This feature
makes it possible to locate bars 36 and bars 30 in the most
suitable manner with respect to central cabinet 10, which position
may not necessarily be alined directly with the center of speaker
cabinets 11, while providing a pleasing symmetrical appearance and
concealing the majority of the extension and retraction mechanism,
even when such cabinets 11 are fully extended. This is particularly
important in the case of bars 30 which are, as noted, offset with
regard to one another rand would otherwise provide an unsightly
appearance, this being overcome by the location of sleeves 31
symmetrical with one another.
It will be understood that according to the invention many
variations are possible in the extension and retraction mechanism
and it may for example be located entirely along the back wall of
the main cabinet and attached to the rear of the speaker cabinets,
and be concealed from view, at least with respect to persons
standing in front of the cabinet, by means of covering panels
retracting within the central cabinet, but such alternative
expedient obviously does not affect the particular concept of
providing a separate extension and retraction mechanism by means of
which the speaker cabinets themselves can be extended entirely
beyond the limits of the central stationary cabinet while yet being
maintained rigid and effective in use even under full power.
Similarly, if it were desired to provide much deeper speaker
cabinets, for example, equal to the depth of the main cabinet, it
might prove to be expedient to dispense with the provision of
speaker cabinet recesses in either side of the main cabinet, and
instead, to merely build the main cabinet and the speaker cabinet
of the same overall design so that the same fitted flush together
with one another and separated one from the other as the speaker
cabinets were extended. However, the various alternatives are not
illustrated here and are deemed to be included within the overall
concept of the invention.
In some cases, it may be found that the form of extension and
retraction mechanism described above may be too costly and result
in the speaker cabinet having only a very limited sales potential.
According to a further embodiment of the invention simple provision
may be made for a much simpler more economical form of extension
and retraction mechanism to be incorporated in a lower priced
speaker cabinet, in which some lesser degree of separation or
spacing between the speaker cabinet will be acceptable, while
retaining the various advantages of the invention, and in
particular, the concealment of the speaker cabinet themselves
within the same cabinet, when not in use. Accordingly, as shown
schematically in FIG. 7, a modified form of the invention may
comprise a main cabinet indicated generally as 100 having a front
101, a back 102 and two ends 103 and may be provided essentially in
the same general layout as the embodiment of FIG. 1, and
incorporating speaker cabinet recesses 104 and intermediate
partitions 105, and intermediate wall members 106, separating the
main cabinet 100 into record storage areas, and providing central
spacing for location of the sound reproduction apparatus, which for
the purposes of this invention, is taken to include radio, record
player, and tape reproduction apparatus with or without associated
speakers, the term sound reproduction apparatus being intended to
be a comprehensive general term covering all or part of a complete
apparatus.
In this modified form of the invention, the speaker cabinets 107
are hingedly mounted along the rear wall 102 at the hinges 108, and
are capable of being swung outwardly into the position shown in
solid line, and swung inwardly into the position shown in phantom,
so that they are fully retracted within the cabinet recesses 104,
when not in use.
The retraction and extension linkage mechanism comprises the
extension arm members 109 which are hingedly connected to the
speaker cabinets as at 110, and at their inner ends are mounted on
two journal pins 111 which are located spaced apart 180.degree. on
a drive wheel 112. Wheel 112 is in turn driven by the reversible
electrical motor 113 through belt drive 114. In order to control
the operation of the motor 113 two micro-switches 115 are provided
around wheel 112, operated by suitable cam means (not shown), and
connected in circuit with the motor 113 by means (not shown) so as
to provide on/off limit control.
Accordingly it will be understood that any suitable manual on/off
control to actuate motor 113 is also provided as in the case of in
the embodiment of FIG. 1, being omitted from the embodiment of FIG.
7 for the sake of clarity.
According to a further modification shown in FIG. 8, a still more
economical version of the invention may be employed in which the
front record storage space is omitted altogether. In the embodiment
of FIG. 8, a cabinet indicated generally as 120 having a front 121,
a rear 122 and end 123 (only one being shown for the sake of
clarity) is made, having a somewhat reduced cabinet depth in
relation to the embodiment of FIG. 7. Speaker cabinets 124 are
provided, hingedly mounted at 125 to the back portion 122 are
swingable inwardly and outwardly between the two positions as shown
in FIG. 8 and are connected by suitable linkage means 126 connected
to cabinet 124 at hinge point 127. The other details of the
modification of FIG. 8 are essentially the same as in FIG. 7, the
sound reproduction apparatus being contained in a central
compartment of the cabinet 120, and being omitted for the sake of
clarity.
As will be noted, the modification of FIG. 7 and 8 enables
substantial economies in manufacturing costs to be achieved. In
particular, the main weight of the speaker cabinet is borne
directly on the rear portion of the main cabinet itself, being
hinged directly thereto, the linkage means being provided solely
for the purpose of moving the speaker cabinets between extended and
retracted positions.
The foregoing is a description of a preferred embodiment of the
invention which is given here by way of example only, and without
limitation.
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