Abstract:
A tone arm assembly with an interchangeable tone arm tubes includes a fixed base. A support bracket is connected to the fixed base and rotatable thereon. A tone arm housing is mounted in the support bracket and rotatable therein. A separate straight tone arm tube and an S-shaped tone arm tube both have a connector at one end that is engageable with a connector on the tone arm base. The other ends of the tone arm tubes have another connector for removably attaching a cartridge thereto. The straight tone arm tube and the S-shaped tone arm tube are interchangeably connected to the tone arm housing via the respective connectors. Depending on the desired performance, on the same tone arm base, either the straight tone arm tube can be used for improved anti-skip performance or the S-shaped tone arm tube may be used for improved sound quality.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is related to and claims priority from earlier filed provisional patent application Ser. No. 60/357,450, filed Feb. 15, 2002. 
    
    
     BACKGROUND OF INVENTION 
     The invention relates generally to an improved tone arm assembly for record players. The present invention particularly relates to providing both high fidelity sound performance with anti-skip performance from the same tone arm assembly. 
     It is well known in the art that to reproduce the information recorded on a record, a tone arm is conventionally pivotally mounted at a fixed location upon a chassis adjacent the side of a rotatably mounted turntable. The weight of the tone arm wedges the stylus of a reproducing pick-up assembly into the groove, with the electrical output of the reproducing pick-up being proportional to the lateral displacement of the stylus by the lateral vibration of the groove sides. In a such a record player, grooves of the record carry lateral vibrations that move the stylus of a cartridge connected to a tone arm assembly back and forth at right angles to the groove. The groove is a very slight spiral, and thus almost a perfect circle, with its center corresponding with the center of the disc. Thus, the stylus moves back and forth along a radius from the record&#39;s center. With such a conventional arrangement, it can be seen that the stylus moves through an arcuate path and thus the vibrations of the stylus are not maintained at right angles to the groove as they should be. 
     There are a number of problems typically associated with record players. Most notably, conventional tone arms are prone to skating across the record. As a result of the forces exerted on the stylus of such a conventional tone arm during playing of a record, since there is an angle between the line tangent to the groove and the line between the stylus point and the pivot point of the tone arm, there is a component of force directed radially inwardly of the record which tends to pull the stylus towards the center of the record. This radially directed force may cause the stylus to jump over one or more convolutions of the spiral groove in a skating or skipping action. 
     The danger of a tone arm skating across a record is greatly exacerbated during “scratching” of the record where the turntable is rotated back and forth successively with the stylus still in communication with the grooves of the record. As can be understood, such movement increases the directional forces on the grooves of the record thus increasing the likelihood of skipping or skating. 
     To address such skipping and skating problems which are encountered frequently when scratching, it has been found that the employment of tone arm assembly with a straight tone arm tube reduces the likelihood that the stylus will skip or skate out the grooves during scratching. In general, the path of a straight tone arm reduces the directional forces during scratching. The details of why the path and the configuration of a straight tone arm assembly reduces the skipping and skating during scratching is well known in the art and need not be discussed herein. 
     In addition, the radial forces, created by the conventional tone arm during playing of a record, not only make the record prone to skipping but also reduce the overall sound quality of playback. More specifically, if there is any deviation from the radial vibration of the stylus, a tracking error will result. Such tracking error creates distortion and unpleasant noise in the reproduced sound, as well as increased record wear. Even the slightest tracking error will have an effect of the overall quality of the sound. 
     To address the foregoing problems with directional forces of the stylus in the grooves as they relate to sound quality, many attempts have been made in the prior art to reduce the directional forces for the specific purpose of improving the quality of playback sound. It has been found, as is well known in the art, that the employment of a tone arm assembly with an S-shaped tone arm tube improves the fidelity of the sound played back from the record by improving the signal to noise ratio. In general, the path of an S-shaped tone arm reduces the directional forces during playback for better tracking an high quality playback. The details of why the path and the configuration of an S-shaped tone arm assembly reduces the skipping and skating during scratching is well known in the art and need not be discussed herein. 
     In view of the foregoing, turntables are typically manufactured with a tone arm assembly that is optimized either for anti-skating/anti-skipping or for high fidelity. For anti-skipping, the tone arm assembly is equipped with a straight tone arm tube. Alternatively, the tone arm assembly is equipped with an S-shaped tone arm tube for achieving higher fidelity play over the tone arm assembly with the straight tone arm. Once the tone arm assembly is selected it is permanently installed onto a turntable for use. 
     Known record turntables are specifically configured, by design of the tone arm assembly, to be optimized either for anti-skipping or for high fidelity but not both. Since, users of turntables, such as a disc jockeys, play records with and without scratching, two complete turntables are typically used. One of the turntables has a tone arm assembly with a straight tone arm tube with the other turntable has a tone arm assembly with an S-shaped tone arm tube. When a disc jockey performs at a given venue, the two turntables must be both brought to accommodate both types of performance, that is, high fidelity playback and scratching. 
     As can be understood, the use of two separate turntables is not only cumbersome for transport but is also expensive in that two separate turntables are required to accommodate the two different types of playback style. 
     In view of the foregoing, there is a demand for a tone arm assembly that can accommodate high fidelity playback of records as well as a scratching performance without skipping or skating. There is a particular demand for a single tone arm assembly on a single turntable that can accommodate high fidelity playback of records as well as a scratching performance. Moreover, there is a demand for a tone arm assembly that can accommodate both a straight tone arm tube and an S-shape tone arm tube. There is a demand for a tone arm assembly that can be easily converted from a straight tone arm tube configuration to an S-shaped tone arm tube and back. Also, there is a demand for a tone arm assembly that is modular in construction. 
     SUMMARY OF INVENTION 
     The present invention preserves the advantages of prior art turntables and tone arm assemblies. In addition, it provides new advantages not found in currently available turntables and tone arm assemblies and overcomes many disadvantages of such currently available apparatuses. 
     The invention is generally directed to the novel and unique tone arm assembly and method of converting such an assembly. The assembly has particular use in the disc jockey music industry in that the turntable can be easily converted over from a turntable with an S-shaped tone arm tube with high quality sound to a turntable with a straight tone arm tube for better anti-skip performance. 
     The tone arm assembly of the present invention enables the easiest and most cost-efficient way of providing both high fidelity sound and best anti-skip performance in a single tone arm assembly. The present invention addresses the foregoing problems associated with the prior art while providing superior performance and reliability. 
     The tone arm assembly of the present invention includes a includes a fixed base. A support bracket is connected to the fixed base and rotatable thereon. A tone arm housing is mounted in the support bracket and rotatable therein. A separate straight tone arm tube and an S-shaped tone arm tube both have a connector at one end that is engageable with a connector on the tone arm base. The other ends of the tone arm tubes have another connector for removably attaching a cartridge thereto. The straight tone arm tube and the S-shaped tone arm tube are interchangeably connected to the tone arm housing via the respective connectors. 
     For example, for better anti-skip performance during play, such as during scratching, it may be preferred to connect the straight tone arm tube to the tone arm base. In the event high fidelity with high signal to noise ratio sound is desired, the straight tone arm tube is disconnected from the tone arm base. The S-shaped tone arm tube is then connected to the tone arm base using a connector which is identical to the connector used to connect the straight tone arm tube to the tone arm base. When better anti-skip performance is desired, the S-shaped tone arm is then disconnected and the straight tone arm is then re-connected. As a result, the straight tone arm tube and the S-shaped tone arm tube can be easily interchanged on the same tone arm base depending on the desired performance. 
     It is therefore an object of the present invention to provide a single tone arm assembly that can provide both high fidelity sound and anti-skip performance. 
     It is an object of the present invention to provide a tone arm assembly that can accommodate both a straight tone arm tube and an S-shaped tone arm tube. 
     It is a further object of the present invention to provide a tone arm assembly that can easily switch between a straight tone arm tube and an S-shaped tone arm tube without special tools. 
     Another object of the present invention is to provide a tone arm assembly that is modular in construction to easily accommodate different type of tone arm tubes. 
     It is a further object of the present invention to provide a tone arm assembly that obviates the need to use two different turntables to provide both high fidelity sound and anti-skip performance. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS 
     The novel features which are characteristic of the present invention are set forth in the appended claims. However, the invention&#39;s preferred embodiments, together with further objects and attendant advantages, will be best understood by reference to the following detailed description taken in connection with the accompanying drawings in which: 
     FIG. 1 is a top view of a turntable with the tone arm assembly of the present invention employing a straight tone arm tube; 
     FIG. 2 is a top view of the turntable with the tone arm assembly of the present invention employing an S-shaped tone arm tube; 
     FIG. 3 is a close-up perspective view of the tone arm assembly of the present invention shown in FIG. 1; 
     FIG. 4 is a close-up perspective view of the tone arm assembly of the present invention shown in FIG. 2; 
     FIG. 5 is an exploded front perspective view of the tone arm assembly of FIG. 3; 
     FIG. 6 is an exploded front perspective view of the tone arm assembly of FIG. 4; and 
     FIG. 7 is an exploded rear perspective view of the tone arm assembly of FIG.  3 . 
    
    
     DETAILED DESCRIPTION 
     Turning first to FIGS. 1 and 2, top views of a turntable  12  employing the tone arm assembly  10  of the present invention is shown. FIG. 1 shows the tone arm assembly  10  configured with a straight tone arm tube  14  while FIG. 2 shows the tone arm assembly configuration  10  with an S-shaped tone arm tube  16 . 
     The tone arm assembly  10  of the present invention may be installed on many different types of turntables  12 . The turntable  12  of FIGS. 1 and 2 is shown by way of example to illustrate a typical environment for the tone arm assembly  10  of the present invention. The turntable  10  includes a turntable base  18  with a rotating platter  20  and a center spindle  22 . The platter  20  is preferably made of die-cast aluminum. The usual strobe pattern  24  is provided on the edge of the platter for precise speed adjustment. The tone arm assembly  10  is placed in a location proximal to the platter  20  that optimizes both playback with a straight tone arm  14  and with an S-shaped tone arm  16 . This location enables the cartridge  26  and stylus  28  (shown in FIG. 7) to be positioned as parallel as possible within the grooves of a record (not shown) when either one of the tubes  14  or  16  are employed. The platter  20  is preferably powered by a direct drive high torque motor (not shown) for reliability and precision. 
     A number of controls  30  are provided for normal operation of the turntable, such as a play/pause, RPM, motor and pitch fader controls. A display  32  may also be provided to visually indicate the operation of the turntable  12 , such as speed or volume. As can be understood the type and layout of the controls  30  can be modified to suit the particular needs of the turntable. 
     Most importantly, the turntable  12  construction includes a tone arm assembly  10 . 
     As seen in FIG. 1, the tone arm assembly  10  is shown equipped with a straight tone arm  14  which provides a sweep path  34 . It is generally known in the prior art and preferred in the industry that a typical straight arm sweep path  34  of the free end of the tone arm tube  14  pass inside between the center spindle  22  and the fixed base  36  of the tone arm assembly  10 . This illustrated sweep path  34 , characteristic of a tone arm assembly  10  with a straight tone arm  14 , provides for improved anti-skip and anti-skate performance. 
     FIG. 2 illustrates the same tone arm assembly  10  equipped with an S-shaped tone arm  16  which provides a sweep path  38 . It is generally known in the prior art and preferred in the industry that the free end of the S-shaped tone arm tube  16  pass outside of the center spindle  22 . This illustrated sweep path  38 , characteristic of a tone arm assembly  10  with an S-shaped tone arm  16 , provides for improved sound quality with a higher signal to noise ration over turntables  12  with a tone arm assembly  10  equipped with a straight tone arm tube  14 . 
     As will be described in detail below, the present invention enables the same turntable  12  and tone arm assembly  10  to be used to provide both the sweep path  34  of FIG. 1 for a straight tone arm tube  14  as well as a the sweep path  38  of FIG. 2 for an S-shaped tone arm tube  16 . In the prior art, tone arm assemblies are permanently configured to have either a straight tone arm tube or an S-shaped tone arm tube. In the prior art, the tone arm assembly is permanently mounted to the turntable body for the purposes of providing either the sweep path  34  of FIG. 1 or the sweep path  38  of FIG.  2 . 
     Turning now to FIGS. 3-7, details of the construction of the tone arm assembly  10  of the present invention is shown. The unique modular construction of the tone arm assembly  10  of the present invention enables either a straight tone arm tube  14  or an S-shaped tone arm tube  16  to be used on the same tone arm base  36 . 
     Turning specifically to FIG. 3, a tone arm base  36 , with a longitudinal axis, is securely fixed to the top surface  12   a  of the turntable  12  in a position proximal to the platter  20 . A support bracket  40  is affixed to the tone arm base  36  and is capable of rotating about the longitudinal axis of the tone arm base  36 . The bracket  40  includes a pair of upstanding walls  42  for pivotally receiving a tone arm housing  44  therein. A pin  46 , for example, is routed through apertures  48  proximal to the top edges  42   a  of the upstanding walls  42 . As a result, the tone arm housing  44  pivots up and down about the pin  46 . It is possible to use protrusions (not shown) extending outwardly from the sides of the tone arm housing  44  instead of pin  46  completely therethrough. It should be understood that the configuration of the tone arm base  36  and tone arm housing  44  is merely an example of different constructions that can be used. Other configurations can be employed and still be within the scope of the present invention. Whatever structure is used, the tone arm housing  44  is pivotally mounted relative to the support bracket  42  and the support bracket is rotatable relative to tone arm base  36 . 
     The tone arm assembly  10  of FIG. 3 includes a straight tone arm tube  14  which is connected to the tone arm housing  44  which is pivotally connected to the support bracket  42 . FIG. 4 shows the an S-shaped tone arm tube  16  which is connected to the tone arm housing  44  which is pivotally connected to the support bracket  42 . In prior art tone arm assemblies, the tone arm tube is permanently mounted to the tone arm housing. However, in accordance with the present invention, the tone arm tube, either straight, S-shaped or otherwise, is removably connected to the tone arm housing  44 . 
     The tone arm assembly  10 , which is shown in FIGS. 3 and 4, also includes an integrated cueing system  46  with a cantilever height adjustment  48  with track  50  for elevating the tone arm tube  14 ,  16  and cartridge  26  (shown in FIG. 7) above the record surface as well as for gently lowering the cartridge  26  onto the record surface in the desired position for playback. This height adjustment allows for a variety of set-ups for a head shell and cartridge  26  to be utilized with only minor adjustments. A latch  54  is also provided for securing the tone arm tube  14 ,  16  when the player is not in use. Also, an anti-skate counterweight  56  is provided on the opposite end of the tone arm housing  44  to where the tone arm tube  14 ,  16  is connected. The counterweight  56  is threadably mounted on a post  58  and is adjusted in and out to change the pivot action of the tone arm housing  44  and the resultant pressure placed on the stylus  28  during playback for anti-skate adjustment. The cueing system  46  with height adjustment, latch  54  and anti-skate components are so well known in the art that further details of their construction and operation need not be discussed herein. 
     FIG. 5 is an exploded front perspective view of the tone arm assembly  10  of the present invention showing the removable interconnection of the tone arm tube  14  to the tone arm base  36 . More specifically, the tone arm tube  14  includes a first end  14   a  and a second end  14   b . The first end  14   a  interconnects and electronically interfaces with the tone arm housing  44 . A boss  60  is provided on one side of the tone arm housing  44  with, preferably, a array of four electrical contacts  62 . One pair of the contacts  62  corresponds to the left stereophonic channel while the other pair corresponds to the right stereophonic channel. As shown in FIG. 7, a corresponding array of four electrical contacts  64  are present on the first end  14   a  of the tone arm tube  14  for electrical communication with the contacts  62  on the tone arm housing  44 . 
     To maintain the first end  14   a  of the tone arm tube  14  in electrical communication with the tone arm housing  44  via their respective contacts  64 ,  62 , a keyed locking collar arrangement is preferably used. A tube  68  with a pair of slots  70  is affixed about the boss  60 . A pair of protrusions  72 , which emanate outwardly from a reduced neck portion  14   c  of the first end  14   a  of the tone arm tube  14  are received in slots  70  in the tube  68 . A threaded collar  66 , with female threads  74 , resides over the outer circumference of the tone arm tube  14 . The female threads  74  engage with the male threads  76  on the exterior surface of the tube  68  with is affixed about the boss  60 . As a result, as the collar  66  is threaded onto the tube  68 , the first end  14   a  of the tone arm tube  14 , namely, the array of four contacts  64  are drawn into electrical communication with a similarly arranged array of four electrical contacts  62  on the tone arm housing  44 . Thus, the tone arm tube  14  is not only electrically connected to the tone arm housing  44  but also structurally secured thereto. The interior of the tone arm tube  14 , while not shown, includes the typical electrical wires spanning from the first end  14   a  to the second end  14   b  as found in prior art tone arm tubes. As a result, a continuous electrical interconnection is maintained from the cartridge  26  to the electronics of the turntable  12 . 
     Thus, the tone arm tube  14  can be structurally and electrically disconnected from the tone arm housing  44  without special tools. In contrast, prior art tone arm tubes are permanently electrically and structurally connected to the tone arm housing  44 . 
     While the foregoing interconnection structure is preferred, other interconnection configurations may be employed and still be within the scope of the present invention. For example, instead of a locking collar  66 , a snap lock connection may be used. 
     Still referring to FIG. 5, the second end  14   b  of the tone arm tube  14  is also provided with an array of electrical contacts  78  which are preferably identical to the array of contacts  62  found on the boss  60  of the tone arm housing  44 . As show in FIG. 7, a phonograph cartridge  26  is structurally and electrically interconnected to the second end  14   b  of the tone arm tube  14 . The cartridge  26  also includes an array of electrical contacts  52  for electrically interconnecting to the array of contacts  78  on the second end  14   b  of the tone arm tube  14 . A second locking collar  80  and slotted tube  82 , of the same type used to the connect the first end  14   a  of the tone arm tube  14  to the tone arm housing  44 , is preferably used to connect the second end  14   b  of the tone arm tube  14  to the cartridge  26 . Details of this interconnection need not be further addressed herein as the operation of this second locking collar arrangement is identical to the operation of the first locking collar arrangement to connect the first end  14   a  of the tube  14  to the tone arm housing  44 . As a result, a continuous electrical path is provided from the cartridge  26 , through the tone arm tube  14 , through the tone arm housing  44  and into the electronics of the turntable  12 . 
     Referring now to FIG. 6, the same tone arm assembly  10  of FIG. 5 is employed, in modular fashion, to accommodate an S-shaped tone arm tube  16 . Essentially, the assembly of FIG. 6 is identical to the assembly of FIG. 5 except that an S-shaped tone arm tube  16  has been interchanged with the straight tone arm tube  14 . This is possible due to the modularity of the tone arm assembly  10  of the present invention. 
     The S-shaped tone arm tube  16  is similar in construction to the straight tone arm tube  14  except that it has an S-shaped configuration. The S-shaped tone arm tube  16  also includes a first end  16   a  which connects to the tone arm housing  44  by a locking collar arrangement, generally referred to as  84  and a second end  16   b  which connects to a cartridge  26 . The first end  16   a  of the S-shaped tone arm tube  16  includes a reduced neck portion  86  with an array of contacts (not seen in FIG. 6) and protrusion keys  88  to interconnect with the tone arm housing  44  in the same way as the first end  14   a  of the straight tone arm tube  14 . Also, the second end  16   b  of the S-shaped tone arm tube  16  includes another array of electrical contacts for receiving the electrical contacts of the phonographic cartridge  26  shown in FIG.  7 . 
     From the foregoing, the tone arm tube can be easily interchanged between different types of tone arm tubes, namely straight tone arm tubes  14  and an S-shaped tone arm tubes  16 . The common type of interconnection facilitates the connection and disconnection of the tone arm tubes between a cartridge  26  and a tone arm housing  44 . With the tone arm assembly  10  of the present invention, the overall type and performance of the turntable  12  can be quickly and easily converted from one type to another by interchanging the tube configuration. The unique and novel tone arm assembly of the present invention enables interchangeability of different types of tone arm tubes with the same tone arm assembly  10  on the same turntable. 
     It is preferred that the tone arm assembly  10 , including the tone arm tubes  14 ,  16  be manufactured of metal material, such as die-cast aluminum but may be of other materials and still be within the scope of the present invention. Other components, such as the latch  54  and track  50 , may be made of plastic or other materials. 
     It would be appreciated by those skilled in the art that various changes and modifications can be made to the illustrated embodiments without departing from the spirit of the present invention. All such modifications and changes are intended to be covered by the appended claims.