US3912281A

US3912281A - Sound reproduction apparatus

Info

Publication number: US3912281A
Application number: US359795A
Authority: US
Inventors: Stephen A Platt
Original assignee: Individual
Current assignee: Individual
Priority date: 1972-01-19
Filing date: 1973-05-14
Publication date: 1975-10-14
Anticipated expiration: 1992-10-14

Abstract

A sound reproducing apparatus capable of manual operation to reproduce audible intelligence recorded in a spiral groove on a disk. The apparatus includes a base member on which is supported a rotatable turntable over which extends a hollow sound transmission arm having a rigid sounding board specially flexibly mounted at the upper edge thereof to this arm. A needle holding clip is attached to the lower free edge of the sounding board such that it will track within the spiral groove of the disk which is rotated by the operator to reproduce the recorded information.

Description

Unite States atet [1 1 1111 3,912,121

Platt 1451 Oct. 14;. '197s- [54] SOUND REPRODUCTION APPARATUS 2,859,974 11/1958 'Jauquet 1. 27 4/16 3 41 12 l W' [75] Inventor: Stephen A. Platt, Grand Haven, 5526 l 968 ener 274/16 Mi h FOREIGN PATENTS OR APPLICATIONS 'AsSignees: Stephen A. Flatt; vernet B. Plan 1,130,457 2/1957 France 274/25 both of Grand Haven, Mich. Primary Examiner-R1chard E. Aegerter Flledi y 1973 Assistant ExaminerCharles E. Phillips [21] APP N05 3599795 Attorney, Agent, or FirmPrice, Heneveld, Huizenga & Cooper Related US. Application Data [63] Continuation-impart of Ser. No. 219,105, Jan. 19, [57] ABSTRACT I972, abandoned.

A sound reproducing apparatus capable of manual op- 52 us. c1 274/16; 274/1 G; 274/24 R reproduce. audible intelligenc? recorded in a 51 Int. Cl. G1 1b 3/10 spral gmwe a f The apparatus mcludes a base [58] Field of Search 274/1 G 24 R 25 35 whch Supported a rotatable 274/16 over whlch extends a hollow sound transmission arm having a rigid sounding board specially flexibly References Cited 4 mounted at the upper edge thereof to this arm. A needle holding clip is attached to the lower free edge of UNITED STATES PATENTS the sounding board such that it will track within the 1,072,477 9/1913 Lumiere 274/35 R spiral groove of the disk which is rotated by the opera- 1,146,418 7 1915 Fuller 274 1 0 tor to reproduce the recorded information 1,364,201 1 I921 Laurencich 274/24 A 1,728,668 9 1929 Davis 274/16 29 Uwms, 16 Drawlng Flgures Sheet 1 of 5 3,912,281

US. Patent Oct. 14, 1975 Patent 0a. 14, 1975 Sheet 2 of5 3312 281 US. Patent Oct. 14,1975 Sheet30f5 3,912,281

" n: W W d 4 Hg ll4 FIGSA 146.9 B H63 6 ua Ale M 210 m 12a H8 $16.90 FIG.9E

Wes."

U.S.' Patent 0m. 14, 1975 Sheet 4 of 5 3,912,281

FIG I?) US; Patent Oct. 14', 1975 Sheet 5 of5 3,912,281

llOo w G F SOUND REPRODUCTION APPARATUS CROSS REFERENCE TO RELATED APPLICATION This application is a continuation-in-part of application Ser. No. 219,105, filed Jan. 19, 1972 and entitled SOUND REPRODUCTION APPARATUS, now abandoned.

BACKGROUND OF THE INVENTION The present invention relates to a sound reproduction apparatus for use with a disk having audible intelligence recorded in a spiral groove therein, and particularly to such an apparatus capable of being manually operated.

It is frequently desirable to have a mechanically operated sound reproducing apparatus which does not rely on electrical power for its operation and which provides relatively high fidelity sound reproduction. Such a need exists particularly in underdeveloped areas or countries where electrical power is not generally available. During the early stages of development of phonograph players, several mechanically or manually rotated players were available that employed diaphragmtype devices to convert the mechanical movement to audible sounds. Such apparatuses, although providing some fidelity of reproduction, were relatively expensive to manufacture several years ago and would be even more so today. There is a definite need today for a very inexpensive record player capable of being manually operated as for educational and instructional purposes in underdeveloped areas of the world, and/or for a convenient study aid where electricity is not readily available.

There have been attempts in recent years to provide a novel player that would fill this need. Among the types tried were the use of an inverted V-shaped piece of paperboard having a needle on one lower edge, the other edge being fixed, and the apex of the V forming a hinge to allow the needle to move radially on the record disk. The fidelity of this device is poor however. The hinge is first in compression (when the V is small) and then later is in tension (when the V is larger). Such a device is unable to track micro-groove recordings since side forces will exist on the needle tending to push it out of the groove. Another type had the needle mounted to one edge of a resonator plate which was basically fixed in position and had rubber bands to hold the needle in the groove. As might be expected, this was not applicable to playing micro-groove records, and in fact required a somewhat special disk or record. These were mechanically operated sound reproduction devices which were not designed to reproduce information recorded on modern day microgroove records. These devices do not provide adequate fidelity play-back for serious use of the device. In summary, such devices, although satisfying the requirement of being inexpensive and not requiring electricity, do not provide reasonable reproducing fidelity, nor can they be employed with micro-groove recordings.

Typical patents are U.S. Pat. No. 2,859,974, J. Jauquet, issued Nov. 11, 1958, and U.S. Pat. No. 3,415,526, J. S. Wiener, issued Dec. 10, 1968.

SUMMARY OF THE INVENTION The apparatus of the present invention provides a very inexpensive manually operable sound reproducing apparatus that can even be manufactured from cardboard, paperboard, preferably from molded plastic material. The device employs a unique rigid sounding board having a stylus attached to one edge thereof and having the opposite edge flexibly coupled to a hollow sound tube such that the sounding board covers an open end of the sound tube. The sound tube and sounding board are lightweight such that the stylus can track in modern micro-groove recordings and provide relatively high fidelity reproduction of the audio information contained thereon. The stylus is specially mounted to the sounding board for faithful conversion of its mechanical movement to the sounding board.

Apparatus embodying the present invention includes a base member having a turntable rotatably mounted thereto, which is adapted to receive a disk recording to be rotated by an operator, usually the listener. The hollow sound tube has a sounding board mounted across one end and with one board edge flexibly mounted to the sound tube. The opposite edge of the sounding board has a stylus holding clip attached thereto for retention of the stylus. The sounding board and sound tube are mounted to the base by a gimbal pivot such that the stylus mounted to the clip will freely track in the spiral groove of a recording disk on the turntable to reproduce information recorded thereon.

It is an object of the present invention therefore, to provide a unique, practical sound reproducing apparatus capable of being manually operated.

It is an additional object of the present invention to provide a relatively inexpensive sound reproducing apparatus capable of manual or mechanical operation, and that provides good fidelity reproduction of information recorded in a spiral groove on a disk.

It is an additional object of the present invention to provide a sound reproducing apparatus that is inexpensive and can be employed with micro-groove recordings to reproduce information thereon.

It is an additional object of the present invention to provide a portable sound reproducing apparatus that does not rely upon electrical power for its operation, can be operated by children or adults, by persons with no technical training, and without electrical power. It is convenient to assemble from inexpensive components, is extremely lightweight to carry from place to place, is compact in size and shape, and is capable of formation from even cardboard or paperboard, or preferably vacuum formed polymer.

Another object of this invention is to provide an inexpensive record player that actually provides a practical device capable of manual rotation of the disk while reproducing human voice range sounds faithfully from even micro-groove records.

The novel record player reproduces the human voice range frequency using an inexpensive piece of stiff corrugated panel and vibrating this with a pick-up stylus fastened to one edge of the panel.

Another object of this invention is to provide an inexpensive record player capable of reproducing human voice range sounds with high fidelity, and of reproducing sounds in the music range of frequencies with reasonable fidelity. The embodiment of the invention capable of these results employs a stiff sound board of foam polymer to which the pick-up stylus is attached. The foam polymer sounding board preferably is mounted at the end of a polymeric hollow sound arm or tube.

These and several other objects of this invention will be readily apparent upon studying the detailed disclosure to follow.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of one form of the sound reproducing apparatus in a closed, carrying position;

FIG. 2 is a perspective view of the sound reproducing apparatus in an opened position showing the turntable spindle and the turntable prior to being mounted on the spindle;

FIG. 3 is a perspective view of the sound reproducing apparatus with a recording disk resting thereon for play-back;

FIG. 4 is a plan view of the sound tube and sound board mounted thereon;

FIG. 5 is a bottom view of the sound tube and sound board shown in FIG. 4;

FIG. 6 is a detailed view of a portion of the gimbal pivot assembly employed with the sound tube shown in FIGS. 4 and 5;

FIG. 7 is a detailed view of the gimbal pivot assembly;

FIG. 8 is a front oblique elevational view of the sound tube and sound board;

FIGS. 9A-9E are detailed views showing the manufacturing sequence of the needle holding clip which is attached to the sound board;

FIG. 10 is a detailed view of the turntable spindle and turntable bearing;

FIG. 11 is an exploded view of the turntable spindle and bearing shown in FIG. 10, the bearing shown in cross section;

FIG. 12 is a perspective view of a second form of sound tube and sound board;

FIG. 13 is a bottom view of the second form of sound tube and sound board;

FIG. 14 is an elevational view of the second form of sound tube and sound board viewed from the opposite side as that in FIG. 12;

FIG. 15 is a bottom view of the second form of sound tube and sound board, with part of the sound tube removed to depict the interior; and

FIG. 16 is an elevational view of the second form of sound board.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIGS. 1, 2 and 3 in detail, there is shown a sound reproducing apparatus 10 comprising a base 12 and a lid 14 which is removably mounted to the base. As shown in FIG. 3 the lid 14 can be fitted in orthogonal relationship to the base 12 during use. Slots 13 along the edges of base 12 facilitate such mounting. The base 12 includes a rear wall 16 which is folded upwardly from the base 12 and has a forwardly folded projection 18 with a lip 19. Member 18 can serve as a shelf together with lid 14 for holding written material (which may accompany an instructional record) at an angle for viewing during operation of the device. Mounted to the base 12 along one edge thereof, is a rectangular chamber 20 having a pair of apertures 22 in one end thereof and an oval aperture 24 in one side thereof as shown in FIGS. 2 and 3. The remaining sides of the chamber 20 are enclosed.

The base 12, lid 14, chamber 20, rear wall 16 and projection 18 can all be formed from inexpensive corrugated cardboard folded to form a conveniently handled rectangular closed package as shown in FIG. 1. The base 12, rear wall 16 and projection 18 can be formed from a single piece of corrugated paperboard or cardboard by folding the rear section of the base 12 at right angles twice. The base 12 and chamber 20as well as the lid 14 and projection 18 could be molded from plastic as by vacuum molding in which case chamber 20 would not include a bottom surface but would be closed by resting the apparatus 10 on a flat surface. Both are inexpensive both in forming cost and in material cost.

The base 12 includes a spindle 30 mounted at one corner thereof which is adapted to receive a spindle bearing 35 mounted to a turntable platen 37. FIGS. 10 and 11 illustrate the manner in which the spindle 30 is attached to the base member 12 by means of an aperture 15 adapted to receive the base 31 of the spindle 30. Spindle 30 further includes a conical member 32 which extends upwardly from the base 31 and has a cylindrical tip 33 extending therefrom as shown in FIGS. 10 and 11. The spindle bearing 35 includes a circular base member 36 having a somewhat smaller circular projection 38 extending therefrom which is adapted to fit within an aperture 39 on the turntable platen 37. A sleeve 41 is integrally molded with the

cylindrical members

36 and 38 and has an aperture 42 therethrough adapted to receive the cylindrical portion 33 of the spindle 30. The spindle bearing 35 further includes a conical aperture 43 formed in the base member 36 and member 38 and shaped to conform to the shape of the conical section 32 of the spindle 30. Thus the spindle bearing 35 to which the turntable platen 37 is cemented as shown in FIG. 10, fits over the spindle 30 in a rotatable sliding engagement therewith such that the turntable 37 is free to rotate with respect to the base member 12. Also the turntable platen 37 and bearing 35 therein are freely removable from the spindle 30 (FIG. 2) such that the turntable platen can be fitted within the container formed by the base 12 and lid 14 during transportation of the apparatus.

The spindle 30 is positioned on the base 12 in the front corner as shown in FIG. 2 such that when a disk recording 50 is mounted on the platen 37, the edges of the disk 50 will clear chamber 20 and lid 14 as shown in FIG. 3. The dimensions of the base are chosen such that a conventional l2 inch 33%; rpm record can be employed with the play-back apparatus.

A pick-up arm assembly includes a sound tube 80 having a sound board assembly 90 attached at one end thereof. The sound tube 80 comprises a cylindrical hollow tube having a diameter for example approximately 2 inches and which is coupled at one end to the base member 12 by means of a gimbal pivot assembly (FIG. 7). The gimbal pivot assembly 65, shown in detail in FIGS. 6 and 7, includes a clip 66 mounted to the chamber 20 across the top surface thereof, and a cross arm assembly shown in FIG. 6. Cross arm assembly 70 has a vertical member 72 with one end adapted to fit within an aperture 67 of clip 66 and the opposite end adapted to fit within an aperture 68 in the base 12.

Member 72 is thereby allowed to freely rotate about its axis between clip 66 and base 12. A horizontal member 74 is securely attached to the vertical member 72 and includes step-cut ends 76 and 78. The horizontal member 74 is adapted to be fitted within the tube 80 such that the end 76 projects into an aperture 84 in tube 80 and end 78 fits within a second aperture 82 in tube 80.

Thus, tube 80 is allowed to freely rotate about the axis of horizontal member 74. It is freely movable in two directions, i.e., vertically and horizontally as depicted.

As shown in FIGS. 4 and 5, tube 80 further includes an elongated slot 86 and a second elongated slot 88 extending from an end 83 forwardly beyond the cross arm assembly 70. The

apertures

86 and 88 provide clearance between tube 80 and the vertical member 72 as the tube is raised and lowered during use. Also, the end 83 of tube 80 adjacent the gimbal assembly is tapered somewhat so that it will clear the inner surface of the outside wall of chamber 20 when the tube, which extends into aperture 24 of chamber 20, is horizontally moved during use. It is seen that the oval aperture 24 in the internal wall of chamber 20 is sufficiently large to allow the sound tube to fit therein and freely move in horizontal and vertical directions with a clearance space between the outer surface of tube 80 and the peripheral edges of the aperture 24.

The sound board assembly 90 is shown in detail in FIGS. 4, 5 and 8. The assembly 90 comprises a relatively flat rectangular board 92 which has an inner surface 94, an outer surface 96, a top edge 95, and a bottom edge 97. An upper portion of the inner surface'94 adjacent the top edge 95 of board 92 is flexibly mounted to a tapered end 89 of the tube 80 (remote from end 83) by means of a resilient material 99, preferably a resilient foam polymer as of rubber or plastic (e.g. polyvinyl chloride, polyurethane or the like) to which board 92 and edge 89 are cemented. The material 99 is shaped such that the board 92 is joined to the upper portion of edge 89 and is substantially parallel to the edge 89 of the tube 80. A slight gap 100 is formed between the inner surface 94 of the board 92 and the lower portion of edge 89 of tube 80. This gap or spacing should be kept small, but sufficiently wide that the board, when vibrating, will not touch the tube. Thus it is seen that, with this mounting arrangement, the board 92 can be readily moved slightly in relation to the open tapered end 89 of the tube 80 by reason of the flexible coupling between the board 92 and the tube 80 offering negligible resistance to board vibration movement of thousandths of an inch.

The board 92 is fabricated from a lightweight stiff material. One of the most effective materials found is that of corrugated construction, i.e. having surface layers bonded to and spaced by undulated corrugations such as conventional corrugated cardboard as in the first form of the invention depicted. In the preferred embodiment of the first form as shown in FIG. 8, the corrugations 93 extend in the horizontal direction, i.e. between the two free edges of the board. The freedom of motion of the rectangular board 92 in relation to the sound tube 80 permitted by the material 99 is employed to generate sound waves corresponding to information recorded on a disk 50, by means of a stylus 120 which is attached to the sounding board 92 with stylus holding clip shown in detail in FIGS. 9A9E.

The stylus holding clip 110 is fabricated from a substantially rectangular blank 112 of aluminum approximately 0.015 inches thick. As shown in FIG. 9A, blank 112 has a locking tab 114 integrally formed on one edge and a longer folding tab 116 integrally formed on an opposite edge. As shown in FIG. 9B the folding tab 116 is folded over the blank 112 such that it contacts the surface of the blank. The next step is illustrated in FIG. 9C where it is seen that the locking tab 114 is folded over the folding tab 116 and then pressed down at the area 115 to securely hold the folding tab and

locking tab

116 and 114, respectively, in place against the surface of the blank 112.

FIG. 9D is a front elevational view of the structure shown in FIG. 9C after a stylus has been cemented to the center of blank 112 along the longitudinal axis of the folded tab 1 16 on the surface of blank 112 opposite the tabs 114 and. 116. As shown in FIG. 9E, the

sides

117 and 118 of the resultant structure are folded upwardly forming a U-shaped clip 110 having the stylus 120 on the bottom and the folded over

tabs

114 and 116 between the

sides

117 and 118. The dimensions of the clip 110 are such that the

sides

117 and 118 can be manually force-fitted over the lower edge 97 of the sound board 92 to firmly grasp the board. The folding and locking

tabs

114 and 116 increase the mass of the clip 110 in the area immediately adjacent the stylus 120 to enhance the mechanical coupling between the stylus 120 and the sound board 92.

It has been discovered that by mounting the sound board 92 by the tube 80 at an angle, the area of the sound board which sets up sound waves within the tube 80 is increased thereby increasing the efficiency of operation of the device. In the embodiment shown, angle alpha (FIG. 5) is approximately 27 although this angle is not critical. As angle alpha (a) is decreased, the transverse vibrations of the stylus 120 in groove 52 (FIG. 3) become more effective in vibrating the sound board 92 to generate audible sound. By cutting the end 89 of the tube 80 as shown, angle a can be made relatively small and the total weight of the pick-up arm assembly 60 for a given length reduced, thereby increasing the compliance of the pick-up arm.

The sound board 92 must be manufactured of a relatively lightweight and rigid material as noted previously. The corrugated cardboard material shown in the first embodiment is generally rectangular in shape with dimensions of 2 /2 inches by 4% inches and a thickness of from 3/32 to /8 inches. The stylus employed in the preferred embodiment is a 16 mil diameter sapphire tapered to a 0.0007 inch i.e. 0.7 mil tip and having a length of 50 mils. The turntable platen 37 is a 7 inch disk of 5/16 inch thick corrugated or formed polymer cardboard. Thus it is seen that the sound reproducing apparatus of the present invention can be very inexpensively manufactured primarily from cardboard material or from inexpensive molded plastic materials. As noted above, the base 12 and chamber 20 could be molded from a single piece of plastic by a vacuum molding process or the like as could be lid 14. The sound tube 80 likewise can be molded in two halves which are then joined to form the tube.

The apparatus built in accordance with the teachings of the present invention provides excellent tracking in micro-groove records since the gimbal arm mounting is at a point roughly tangent to the mean of the groove, thus the stylus has nearly zero side forces. Additionally, the plane of vibration of the stylus is nearly parallel to the center line of the pick-up arm to allow transverse motion of the stylus for all portions of the groove in the disk. Additionally, the stylus pressure, in the order of 13 to 14 grams, is relatively lightweight for a mechanical sound reproducing apparatus. The total mass of the resonating parts including the sounding board 92, the stylus mounting 112 and the stylus 120 is in the order 0.3 grams. The combination is full floating to enhance its frequency response characteristics. For this small mass, therefore, approximately 8 square inches of area of sound board is mechanically vibrated to convert the mechanical perturbations in the groove of the disk into sound waves.

In operation the user places the pick-up arm assembly 60 such that the needle 120 rests in the spiral groove 52 on the surface of the disk 50 between the spindle sleeve 41 and the rear wall 16 of the base 12.

The disk 50 is then manually rotated by placing an end of a pointed object such as a pencil within an aperture 54 in disk 50 and rotating the disk 50 in the direction indicated by the arrow 55. As the disk is rotated, the stylus 120 vibrates in response to the perturbations in groove 52 and transmits the mechanical vibrations cor responding to recorded information through the clip 110 to the rigid sound board 92. The sound board is allowed to freely vibrate by the flexible coupling at the second end 89 of tube 80 such that sound waves are set up within the tube 80 and travel to the first end 83 where they are then emitted from the space between the aperture 24 in the chamber 20 and the tube 80. The volume is adequate for listening in the approximate area of the device where the user must of necessity be located to manually operate the device.

In areas where the ambient noise level is relatively high, a pair of ear plugs 27 and 28 can be employed. A pair of single tubes 23 and as of plastic are inserted in the apertures 22 of the chamber 20 at the open end of the sound tube opposite to the end at which the sound board is flexibly coupled such that the sound waves from tube 80 are transmitted through the open ended

tubes

23 and 25 and to the users ears by means of the hollow ear plugs 27 and 28 attached to the end of the

tubes

23 and 25 remote from their junction with chamber 20.

The first form described, employing a paperboard or cardboard sound board and sound tube, serves well to cover the voice range frequencies. If, however, the device is employed in high humidity areas as in the tropics, continued moisture absorption by these components can result in poorer and poorer sound produc tion. Hence, the sound tube should then be formed of moisture resistant, durable materials such as polymeric materials, as by pressure differential forming techniques. Typical polymers are high impact polystyrene or ABS rubber polymers or the like.

After the above described paperboard construction was originally discovered, experimentation with alternate stiff materials for the sound board, to hopefully enable such to be moisture resistant, has resulted in the further discovery that rigid, foamed, polymeric materials are even superior to corrugated materials in the range of frequency covered and the fidelity of sound. The novel apparatus, using a rigid foamed polymer with a surface skin, for the stiff sound board, was found to actually produce not only voice range sounds from the record with excellent fidelity, but will also produce music range frequencies with reasonable, i.e. passable, fidelity. The polymeric materials are also more stable in adverse atmospheres, especially high humidity atmospheres.

In this second form, the sound board is attached adjacent an open end of the tube, slightly spaced therefrom not only in the lower portion of the board, but also in the upper portion by attaching the upper portion to an extension from the sound tube overhanging the upper edge of the board. This overhang, moreover, is extended to encompass the outer face of the sound board and thereby envelope the sound board, while spaced therefrom. Since the sound board is thereby basically enclosed, not onay is it protected from dust and physical abuse and damage, but the resulting air coupling to the sound radiator board from the enclosed air also is believed to improve the frequency compliance and radiated sound volume.

Referring specifically to FIGS. 12-16, the second form of the pick-up arm assembly a is depicted without depicting the entire player apparatus except to show the disc 50 and chamber 20a for orientation purposes.

Assembly 60a is, as in the first form, supported by a gimbal pivot assembly a, has a sound tube a with gimbal 65a on one end and stiff sound board a on its opposite end. Sound tube 80a is of very light, thin walled, very stiff polymeric material to form a hollow elongated tube open at the gimbal end. Typical polymers, as noted, are polystyrene, ABS rubber polymer, and the like. The tube is conveniently formed in two elongated parts 181 and 181', each of generally semi circular cross section, and each having a pair of

radial flanges

183 and 183 to enable securement of the parts as by adhesive bonding. The gimbal end of the tube includes slots 86a and 88a in opposite sides for projection of the two vertical, aligned pivots of the cross shaped gimbal into the housing forming chamber 20a, while the flanges collectively form horizontal radially extending pivot sockets 185 and 185' for the other two horizontal, aligned pivots of the gimbal. Thus, as depicted, the first open end of the tube is adjacent the gimbal mount, and the second end of the tube is open to space 197. The outer or second open end of the tube so formed is at an angle, as in the first form, for the reasons explained, with second board 90a being flexibly attached adjacent thereto at this angle. This sound board is of stiff foam polymer material, with expanded polystyrene foam sheet having been found to work particularly well. As with typical foam sheet stock formed as by extrusion, the two opposite sides have integral skin surfaces. Typically the material will be about mil to 150 mil range thickness, of generally oval configuration, approximately 5 inches on the horizontal axis and 2 /2 inches on the vertical axis, resulting in a sound radiator of only about 1 /2 grams weight. This is almost 50% lighter than and fully as stiff as corrugated paperboard. In fact, it was found that the foamed polystyrene used commonly for egg cartons works very well, a section simply being severed out of the flat planar egg carton lid. The stylus a is attached to one edge by clip 1 10a in the fashion earlier described relative to the first form of the invention. The upper edge area is flexibly attached to the outer end of the tube with resilient coupler material 99a of the type previously described relative to the first form. However, the flexible coupler is in this instance on the outer face of the upper edge portion 89' of the sound board rather than the inner face upper edge portion. The lower portion of the sound board is spaced from the second open end of the tube by spacing 197 (FIG. 15) in the same fashion as explained above.

This arrangement successfully produces sound of reasonable fidelity from a micro-groove disc, within the frequency range of music, as well as producing sound of high fidelity within the vocal frequency range of up to about 3000 cycles per second.

Moreover, the sound production is further improved in frequency compliance, i.e. fidelity, and radiated sound volume by having an extension from the sound tube enclosing the sound board in a manner to create a contained air volume for coupling effect. Specifically, each of the polymeric sound tube halves or parts includes an integral enlargement at the same general angle as the sound board mounting surface, the two enlargements 187 and 187' being cooperatively joined as by adhesive bonding between flanges thereon that constitute extensions of

flanges

183 and 183. The combined enlargements form an outer panel parallel to, adjacent to, but spaced from the outer face of the foam sound board. The spacing 191 (FIG. between the board and this outer cover is about inch or so, determined by the thickness of coupler 99a, to form a relatively small enclosed volume at a sufficient spacing from the board to prevent any contact between the board and the cover. This cover also protects the board from damage, dust, etc. There is also sufficient clearance between the upper edge of the board and the overlying peripheral edge portion of the cover to prevent contact therebetween with the slight vertical displacement movement therebetween when the arm is placed on the disc and the resilient material flexes slightly. An aperture 193 is provided in the lower edge of the cover to allow protrusion of the stylus 120 and its clip mount 110.

Various modifications to the present invention within the scope of the present invention as defined by the appended claims will be apparent to those skilled in the art.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

l. A mechanical sound reproduction apparatus for use with disk recordings, said apparatus comprising: a base; a turntable rotatably mounted to said base for receiving and rotating a disk recording; a hollow thinwalled sound tube having a first open end and a second open end; means for pivotally coupling said first open end of said sound tube to said base for horizontal and vertical movement; a relatively flat and rigid sound board flexibly coupled to an edge of said second end of said sound tube such that a clearance exists between a portion of the edge of said sound board and the corresponding portion of said second end of said sound tube to allow said sound board to freely vibrate; means for mounting a stylus adapted to fit within a groove in a disk recording, to an edge of said sound board adjacent said clearance so that stylus vibrations carried by information recorded in the groove are transmitted to said sound board which generates audible sound waves in said sound tube.

2. The apparatus as defined in claim 1 wherein said means for pivotally coupling said first end of said tube to said base includes a gimbal pivot assembly coupled between said base and said sound tube.

3. The apparatus as defined in claim 2 wherein said coupling means further includes a chamber having an aperture therein adapted to receive said first end of said sound tube; said aperture being larger than the cross section of said sound tube, and wherein said gimbal pivot assembly is mounted adjacent said aperture such that said first end of said sound tube projects into said chamber through said aperture.

4. The apparatus as defined in claim 1 wherein said sound tube is formed from a cylinder of cardboard and said second end is cut at an acute angle to the longitudinal axis of said tube.

5. The apparatus as defined in claim 1 wherein said flexible coupling means comprises resilient foam polymer cemented between a portion of the edge of said second end of said sound tube and one edge of said sound board such that said sound board is substantially parallel to said edge of said second end of said tube.

6. The apparatus as defined in claim 5 wherein said stylus mounting means includes a U-shaped clip having a stylus secured thereto and which is force-fitted to an edge of said sound board opposite said one edge.

7. The apparatus as defined in claim 6 wherein said sound board is corrugated paperboard.

8. The sound reproduction apparatus of claim 1 wherein said sound board is of rigid foam polymeric material.

9. The apparatus of claim 9 wherein said sound tube is of polymer material.

10. A mechanical sound reproducing apparatus adapted to reproduce sound recorded as perturbations in a spiral groove of a disk, said apparatus comprising: a base; a turntable platen rotatably mounted to said base by a bearing assembly; an enclosed chamber mounted to said base and including an aperture therein; a sound tube comprising a relatively thinwalled hollow member having a first end adapted to fit within said aperture of said chamber and a second end;

a gimbal pivot means mounting said first end of said second tube to said base such that said first end extends into said chamber through said aperture; a relatively thin and stiff sound board coupled to an upper edge of said second end of said thin-walled hollow member by flexible coupling means such that a gap exists between a lower edge of said second end of said sound tube and said sound board; said sound board being substantially parallel to the edges of said second end of said sound tube; means for mounting a stylus to an edge of said sound board adjacent said gap such that said stylus is positioned to fit within said spiral groove of said disk recording when said sound tube is positioned over said turntable.

11. The apparatus as defined in claim 10 wherein said bearing assembly comprises a spindle coupled to said base and including an upwardly projecting conical portion, and a turntable bearing fitted within the center of said turntable platen and including a conical aperture therein adapted to receive in sliding engagement therewith said upwardly projecting conical portion of said spindle.

12. The apparatus as defined in claim 10 wherein said sound tube is formed from a cylinder of cardboard and said second end is cut at an acute angle to the longitudinal axis of said tube.

13. The apparatus as defined in claim 10 wherein said flexible coupling means comprises a piece of flexible foam polymer cemented between said upper edge of said second end of said sound tube and an end portion of said sound board.

14. The apparatus as defined in claim 13 wherein said stylus mounting means comprises: a U-shaped clip having a stylus attached to a bottom outside surface thereof; said clip shaped to grasp an edge of said sound board between the upright portions of said clip.

15. The apparatus as defined in claim 14 wherein said sound board is of corrugated construction.

16. Pick-up means for use with a mechanical sound reproducing apparatus to play-back audio information recorded as perturbations in a groove of a recording medium comprising: a hollow elongated thin-walled sound tube having a first open end and a second open end defined by a peripheral edge; a thin, substantially rigid, lightweight, sound board adapted to fit adjacent said second end and shaped to cover said second end when so fitted; flexible joining means coupling an edge of said sound board to a portion of said peripheral edge of said second end of said sound tube, forming a gap between the surface of said sound board and the remainder of said peripheral edge of said second end of said sound tube, enabling said sound board to freely vibrate, in relation to said second end of said sound tube; and means for coupling a stylus to an edge of said sound board adjacent said gap.

17. The pick-up means as defined in claim 16 wherein said flexible joining means comprises a piece of foam polymer cemented between said sound tube and said sound board.

18. The pick-up means as defined in claim 17 in which said sound board is of corrugated construction.

19. The pick-up means as defined in claim 18 wherein said stylus coupling means comprises a clip having a triple thickness central portion to which a stylus is secured, and single thickness upwardly extending sides adapted to grip an edge of said sound board.

20. The pick-up means in claim 16 wherein said sound board is of rigid foam polymeric material.

21. A mechanical sound reproduction apparatus for use with disk recordings, said apparatus comprising: a base, a turntable rotatably mounted to said base for receiving and rotating a disk recording; a hollow thinwalled sound tube having a first open end and a second open end; means for pivotally coupling said first open end of said sound tube to said base for horizontal and vertical movement; a relatively flat and rigid sound board flexibly coupled adjacent said second end of said sound tube such that a clearance exists between a portion of the edge of said sound board and the corresponding portion of said second end of said sound tube to allow said sound board to freely vibrate; means for mounting a stylus adapted to fit within a groove in a disk recording, to an edge of said sound board adjacent said clearance so that stylus vibrations carried by information recorded in the groove are transmitted to said sound board which generates audible sound waves in said sound tube.

22. The apparatus as defined in claim 21 wherein said means for pivotally coupling said first end of said tube to said base includes a gimbal pivot assembly coupled between said base and said sound tube.

23. The sound reproduction apparatus of claim 21 wherein said sound board is of rigid foam polymeric material.

24. A mechanical sound reproducing apparatus adapted to reproduce sound recorded as perturbations in a spiral groove of a disk, said apparatus comprising: a base; a turntable platen rotatably mounted to said base by a bearing assembly; an enclosed chamber mounted to said base and including an aperture therein; a sound tube comprising a relatively thinwalled hollow member having a first end adapted to fit within said aperture of said chamber and a second end; a gimbal pivot means mounting said first end of said sound tube to said base such that said first end extends into said chamber through said aperture; a relatively thin and stiff sound board coupled adjacent an upper portion of said second end of said thin-walled hollow member by flexible coupling means such that a gap exists between the lower portion of said second end of said sound tube and said sound board; said sound board being substantially parallel to said second end of said second tube; means for mounting a stylus to an edge of said sound board adjacent said gap such that said stylus is positioned to fit within said spiral groove of said disk recording when said sound tube is positioned over said turntable.

25. The sound reproduction apparatus of claim 24 wherein an extension from said second end of said sound tube projects around the upper peripheral edge of said sound board and is coupled by said resilient foam polymer to an upper outer edge portion of said sound board.

26. Pick-up means for use with a mechanical sound reproducing apparatus to play-back audio information recorded as perturbations in a groove of a recording medium comprising: a hollow elongated thin-walled sound tube having a first open end and a second open end; a thin, substantially rigid, lightweight, sound board adapted to fit adjacent said second end and shaped to cover said second end when so fitted; flexible joining means coupling an edge of said sound board adjacent a portion of said peripheral edge of said second end of said sound tube, forming a gap between the surface of said sound board and at least the remainder of said second end of said sound tube, enabling said sound board to freely vibrate, in relation to said second end of said sound tube; and means for coupling a stylus to an edge of said sound board adjacent said gap.

27. The pick-up means in claim 26 wherein said sound board is of rigid foam polymeric material.

28. The pick-up means as defined in claim 26 wherein said flexible joining means comprises a piece of foam polymer.

'29. The pick-up means in claim 26 wherein said sound tube is of polymeric material and which pick-up means includes extension portions generally enveloping said sound board, with a lower aperture for extension of said stylus therefrom.

Disclaimer 3,912,28L-Stephen A. PZatt, Grand Haven, Mich. SOUND REPRODUC- TION APPARATUS. Patent dated Oct. 14, 1975. Disclaimer filed Oct. 6, 197 5, by the assignees, Stephen A. PZatt and Vemet B. PZatt. The term of this patent subsequent to Feb. 11, 1992, has been disclaimed.

[Ofiicz'at Gazette Decembea' 16, 1975.]

Claims

1. A mechanical sound reproduction apparatus for use with disk recordings, said apparatus comprising: a base; a turntable rotatably mounted to said base for receiving and rotating a disk recording; a hollow thin-walled sound tube having a first open end and a second open end; means for pivotally coupling said first open end of said sound tube to said base for horizontal and vertical movement; a relatively flat and rigid sound board flexibly coupled to an edge of said second end of said sound tube such that a clearance exists between a portion of the edge of said sound board and the corresponding portion of said second end of said sound tube to allow said sound board to freely vibrate; means for mounting a stylus adapted to fit within a groove in a disk recording, to an edge of said sound board adjacent said clearance so that stylus vibrations carried by information recorded in the groove are transmitted to said sound board which generates audible sound waves in said sound tube.

9. The apparatus of claim 9 wherein said sound tube is of polymer material.

10. A mechanical sound reproducing apparatus adapted to reproduce sound recorded as perturbations in a spiral groove of a disk, said apparatus comprising: a base; a turntable platen rotatably mounted to said base by a bearing assembly; an enclosed chamber mounted to said base and including an aperture therein; a sound tube comprising a relatively thin-walled hollow member having a first end adapted to fit within said aperture of said chamber and a second end; a gimbal pivot means mounting said first end of said second tube to said base such that said first end extends into said chamber through said aperture; a relatively thin and stiff sound board coupled to an upper edge of said second end of said thin-walled hollow member by flexible coupling means such that a gap exists between a lower edge of said second end of said sound tube and said sound board; said sound board being substantially parallel to the edges of said second end of said sound tube; means for mounting a stylus to an edge of said sound board adjacent said gap such that said stylus is positioned to fit within said spiral groove of said disk recording when said sound tube is positioned over said turntable.

21. A mechanical sound reproduction apparatus for use with disk recordings, said apparatus comprising: a base, a turntable rotatably mounted to said base for receiving and rotating a disk recording; a hollow thin-walled sound tube having a first open end and a second open end; means for pivotally coupling said first open end of said sound tube to said base for horizontal and vertical movement; a relatively flat and rigid sound board flexibly coupled adjacent said second end of said sound tube such that a clearance exists between a portion of the edge of said sound board and the corresponding portion of said second end of said sound tube to allow said sound board to freely vibrate; means for mounting a stylus adapted to fit within a groove in a disk recording, to an edge of said sound board adjacent said clearance so that stylus vibrations carried by information recorded in the groove are transmitted to said sound board which generates audible sound waves in said sound tube.

24. A mechanical sound reproducing apparatus adapted to reproduce sound recorded as perturbations in a spiral groove of a disk, said apparatus comprising: a base; a turntable platen rotatably mounted to said base by a bearing assembly; an enclosed chamber mounted to said base and including an aperture therein; a sound tube comprising a relatively thin-walled hollow member having a first end adapted to fit within said aperture of said chamber and a second end; a gimbal pivot means mounting said first end of said sound tube to said base such that said first end extends into said chamber through said aperture; a relatively thin and stiff sound board coupled adjacent an upper portion of said second end of said thin-walled hollow member by flexible coupling means such that a gap exists between the lower portion of said second end of said sound tube and said sound board; said sound board being substantially parallel to said second end of said second tube; means for mounting a stylus to an edge of said sound board adjacent said gap such that said stylus is positioned to fit within said spiral groove of said disk recording when said sound tube is positioned over said turntable.

29. The pick-up means in claim 26 wherein said sound tube is of polymeric material and which pick-up means includes extension portions generally enveloping said sound board, with a lower aperture for extension of said stylus therefrom.