Patent Publication Number: US-7910816-B2

Title: Circular percusive sound generation instrument

Description:
REFERENCE TO RELATED APPLICATIONS 
     This application claims priority of U.S. provisional application Ser. No. 61/049,505 filed on May 1, 2008 having the same title as the present application. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates generally to percussion instruments for musical use and more particularly to a percussive instrument having a case with a circular or connected curve interior surface and multiple high precision balls carried within the case for persistent sound generation. 
     2. Related Art 
     A number of percussive instruments are available for pulsed or shaken sound such as maracas or shakers. U.S. Pat. No. 7,045,695 issued on May 16, 2006 to Cohen describes an exemplary instrument of this type. While having the potential for sound generation based on shaking or pulsing of the instrument resulting in multiple percussive impact of beads carried within the instrument, no potential for persistent sound is available. So called “rain sticks” allow a flow of beads through an orifice in a resonant tube to create a flowing or persistent sound, however the nature of the sound is not easily controllable for musical use. 
     It is therefore desirable to provide a percussive instrument which has the capability for providing pulsed beats as with a maraca but also allows generation of sound with natural persistence. It is also desirable that the instrument be capable of varied sound quality in the persistent sound generation mode. 
     SUMMARY OF THE INVENTION 
     The present invention provides a percussion instrument having a case with an inner surface having a substantially circular profile. One or multiple high precision spherical balls are contained with the case for acceleration on the inner surface in uniform circular motion along the profile to produce a persistent sustained sound. In one exemplary embodiment the case is cylindrical and incorporates two end plates. In a second embodiment the percussion instrument case is torroidal. In a third embodiment the percussion instrument is spherical. Use of varying materials in the case or differing surface textures on the inner surface allows timbre of the instrument to be modified. Motion of the instrument lateral or perpendicular to the circular profile allows the creation of pulsed percussion sounds. 
     A single instrument may be created by interconnection of multiple individual cases having differing numbers of balls or differing materials of construction. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other features and advantages of the present invention will be better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein: 
         FIG. 1  is a partially sectioned pictorial view of a first embodiment of the invention; 
         FIG. 2A  is a side section view of a torroidal embodiment of the invention; 
         FIG. 2B  is a front cross section view of one embodiment of the torroidal instrument shown in  FIG. 2A ; 
         FIG. 2C  is a front cross section view of a second embodiment of the torroidal instrument shown in  FIG. 2 ; 
         FIG. 2D  is a side section view of the torroidal embodiment with a single large ball and vent apertures; 
         FIG. 2E  is a front cross section view of the torroidal embodiment of  FIG. 2D ; 
         FIG. 3A  is a ¾ exploded view of a spherical embodiment of the invention; 
         FIG. 3B  is a cross section view of the spherical embodiment of the invention of  FIG. 3A ; 
         FIG. 3C  is a phantom view of the alternative spherical embodiment of  FIG. 3A  with alternative surfacing; 
         FIG. 4A  is a phantom view of the embodiment of  FIG. 1  employing alternative materials in the end caps; 
         FIG. 4B  is a ¾ exploded view of the embodiment of  FIG. 1  employing alternative materials in the end caps; 
         FIG. 4C  is a ¾ view of the embodiment of  FIG. 1  employing alternative materials in the end caps with the balls in uniform circular motion; 
         FIG. 4D  is a phantom cross section view of an alternative interior surfacing of the embodiment of  FIG. 1 ; 
         FIG. 4E  is a phantom view of a first alternative embodiment showing different shaped end caps; 
         FIG. 4F  is a ¾ exploded view of the embodiment of  FIG. 4E  with different shaped endcaps; 
         FIG. 4G  is a phantom view of a second alternative embodiment with a cone-shaped endcap; 
         FIG. 4H  is a ¾ exploded view of the embodiment in  FIG. 4G  with a cone-shaped endcap; 
         FIG. 5A  is a phantom view of the embodiment of  FIG. 1  with additional circumferential surface grooves; 
         FIG. 5B  is a partial section view of one side of the embodiment of  FIG. 5A  showing the grooves in detail; 
         FIG. 6A  is a ¾ view of a first interior surface treatment; 
         FIG. 6B  is an end section view of a first interior treatment; 
         FIG. 6C  is a ¾ exploded view of a second interior treatment; 
         FIG. 6D  is an end section view of a second interior surface treatment; 
         FIG. 6E  is an isometric end view without endcaps of a third interior surface treatment; 
         FIG. 6F  is a phantom view of the embodiment of  FIG. 1  with 2 chambers and balls within each chamber; 
         FIG. 6G  is a phantom view of the embodiment of  FIG. 1  with 3 chambers and balls within each chamber 
         FIGS. 7A and 7B  are pictorial views of alternative case shapes for the present invention; 
         FIGS. 7C and 7D  are side section views of alternative closed curves for the overall instrument shape; 
         FIG. 8A  is a end section view of three of the embodiments of  FIG. 1  attached together to create a single unit; 
         FIG. 8B  is a phantom view of triple embodiment of using three elements as shown in  FIGS. 3A and 3B ; 
         FIG. 8C  is a side section view of four of the embodiments in  FIG. 2A  attached together as a single unit; and, 
         FIG. 8D  is a phantom view of four unit embodiment of  FIG. 8C . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to the drawings,  FIG. 1  shows an exemplary embodiment of the present invention employing a cylindrical case  10  having end plates  12 . Multiple precision shaped highly spherical balls  14  are contained within the case and an inner surface  16  of the case provides a race for the balls as will be described in greater detail subsequently. For the initial embodiment shown, multiple balls are employed and the balls are shown of consistent size. However as will be described subsequently for alternative embodiments one larger ball or balls of multiple sizes may be employed. The balls can be made of varying materials such as metal, plastic or glass. In alternative embodiments the instrument includes a removable end plate or plug to allow varying numbers and sizes of balls to be interchangeably used within the instruments. Shaking the instrument, either substantially perpendicular to a central axis  18  of the cylinder or, alternatively perpendicular to the caps causes the balls to rebound off opposing surfaces with pulsed beat similar to that associated with maracas and similar instruments. 
     Alternatively, and most indicative of the present invention, the instrument is accelerated substantially tangentially to the circumference of the cylinder and uniform spherical motion of the balls, represented by arrows  17 , is induced along the interior wall. This motion of the balls provides a very low resistance and a persistent sound is generated by multiple orbitals of the balls on the interior surface; producing a “swooshing”, “whirring”, “whizzing” or “buzzing” sound. The high precision spherical shaping of the balls allows the persistence of the sound to continue for an extended period. The sound may be terminated by imparting a lateral acceleration to lift the balls from the surface or by tilting the cylinder to spiral the balls to an end plate. As will be described in greater detail subsequently, alternative materials in the end plates or other distinct sections within the differing embodiments may be employed to alter the sound, mute the sound, or capture the balls to terminate the sound. 
     The two forms of sound generation are easily mixed by the percussionist by holding the cylinder in the hand using a lateral shaking for pulsed percussion and a flick of the wrist to induce the uniform circular motion. The embodiments of the instrument shown in the drawings comprise the basic case only. The case can also be mounted on a fixed or removable handle in alternative embodiments to increase the moment arm for inducing higher accelerations to the balls contained in the instrument both for the pulsed percussion created by moving the balls within the inner volume between surfaces and the uniform circular motion with the balls in contact with the inner surface for the persistent or sustained sound. 
     In alternative embodiments, the length of the cylinder my be less than its diameter to create a disc shaped instrument similar to a tambourine or lengthened to create a can shape providing greater interior surface on the wall and greater distance between end plates. The radius of the case of the instrument is sufficient for the uniform circular motion of the balls to be induced. The radius will range from a minimum of one inch to sizes up to and above 18 inches, depending on the shape of the embodiment and the size of the interior balls. The size of the balls in relation to the size of the embodiment is chosen to effect the timbre, the velocities, and the sustain of the instrument. 
     A second embodiment of the invention is shown in  FIG. 2A  wherein the case is torroidal in shape having a central aperture  20 . As shown in  FIGS. 2B and 2C , the torroidal version is alternatively a cylindrical walled instrument having a square or rectangular cross section with the outer wall  22  of the torroid providing the persistent sound generating inner surface  16  or a circular cross sectioned instrument with the outer hemisphere  24  providing the inner surface. The square cross-sectioned instrument maintains the end plate configuration allowing pulsed sound by motion induced perpendicular to the end surface. With either version, the pulsed maraca-like sound may be generated by motion of the instrument along a directional vector substantially through the center axis  26  with the persistent sound generation accomplished by motion of the instrument tangential to the outer circumference of the torroid to induce the uniform circular motion of the balls along the inner surface. Variation of the torroid depth  28  and overall diameter  30  in alternative embodiments allows modification of the resonant characteristics of the instrument. This embodiment could also be fitted with vent holes as shown in  FIGS. 2D and 2E  such that one or multiple balls, during uniform circular motion, will push air out of the vent holes  29  in rapid succession which produces a vibrato or tremolo sound, or a musical tone when the balls travel past the vents during multiple orbitals of uniform circular motion within the embodiment. 
     A third embodiment is shown in  FIGS. 3A and 3B  wherein the case is spherical. For the embodiment shown in the drawings, the sphere employs two hemispheres  36  and  38  separable on an equator  40  for insertion of balls  14 . With the spherical embodiment, axis  18  is arbitrarily selectable and the chosen axis may be used to vary the timbre as will be described in greater detail subsequently. 
     The embodiments of the instrument described may be fabricated from plastic, metal, mineral, various woods or frame supported diaphragms to create sounds with various timbre for both the shaken pulsed percussive sound and the persistent uniform circular motion sound. Varying combinations of material forms in the cylinder and end plates allows further tailoring of the desired sounds. As exemplary, the end plates of the cylindrical embodiment of  FIG. 1  could be of differing types of plastics or of light laminated wood construction while the case cylinder is metal or plastic as shown in  FIG. 4A-C . A first texture on inner surface  16   a  as shown in  FIG. 4B  will provide a different timbre than a second texture on inner surface  16   b  as shown in  FIG. 4C  when balls  14  are rotating in the orbitals represented by arrows  17 . Alternatively, the end plates  12   a ,  12   b  and  12   c  may be of varying non-planar shapes as in  FIGS. 4E-H . Alternatively the end plates are stretched diaphragms, like a drum head with the case cylinder fabricated from wood. Similar combinations may be employed for the square cross-sectioned torroidal embodiment. For the circular cross-sectioned torroidal instrument a plastic construction allows easy fabrication and is easily adaptable to various surface finishes. 
     In addition to material types, the finish or texture of the inner surface  18  affects the timbre of the persistent sound. As shown in  FIG. 4D , a combination of inner surface textures is created by combining a first cylinder portion  32  having a first inner surface texture  16   c  with a second cylinder portion  34  having a second inner surface texture  16   d . The surface texture may be a function of the material selected for the cylinder portion. A combination of a wood portion with a metal portion provides very different timbres resulting from the balls rotating on that portion. In alternative embodiments, a single cylinder material is used with differing textures applied or machined into portions of the inner surface; as an example one portion having a smooth surface with a second portion having knurled surface. 
     With a multiple textured inner surface, the percussionist may create uniform circular motion on one portion or the other or with light lateral acceleration create a transition from one surface to the other by the rotating balls resulting in a change in timbre during the sustain. 
       FIG. 3C  shows a spherical embodiment of the invention wherein first hemisphere  36  is a soft plastic while second hemisphere  38  is a hard plastic. With practice, the percussionist can initiate rotation of the balls within the sphere on only one hemisphere and by selecting the hemisphere, the timbre of the sound is changed. Alternatively, the balls can be accelerated across an equator  40  of the sphere resulting in a timed mixing of the timbres which can be characterized as a vibrato or tremolo. 
     An enhanced embodiment of the invention is shown in  FIGS. 5A and 5B  wherein concentric circumferential grooves  42  are incorporated in the inner surface. During the persistent sustain of the balls in uniform circular motion within the case minor lateral motion by the percussionist captures the balls within the grooves altering the timbre of the sound during the sustain. The number of grooves may vary and the grooves may have a surface texture differing from the base texture of the inner surface, either smoother or rougher, to further alter the effect of the timbre change. 
     Additionally, surface features transverse to the circumferential direction of the inner surface are employed in alternative embodiments for altering timbre of the generated persistent sustain. Ridges  44  such as that shown in  FIGS. 6A and 6B  create a jump or bounce in the balls as they pass over that feature during their circular motion on the inner surface. Similarly, grooves  46  as shown in  FIGS. 6C and 6D  create an interference with the circular motion which alters the timbre of the sustain. Individual bumps  48  on the inner surface as shown in  FIG. 6E  create a similar interference but only with a portion of the rotating balls. As with the material variance in the case, the surface features may be incorporated over the entire lateral length of the case or only a portion of the length to allow the percussionist to select the desired timbre effect. 
     Multiple chambers may be incorporated in a single instrument to provide varying combined sounds from differing materials, ball diameters or other effects.  FIGS. 6F and 6G  show exemplary embodiments of a two chambered and three chambered instrument. As seen in  FIG. 6F , a double chambered instrument is created by combining in a single case  10  two chambers  10   a  and  10   b , each chamber creating an instrument as shown in  FIG. 1 . Balls  14   a  of a first diameter in chamber  10   a  and balls  14   b  of a second diameter in chamber  10   b  create differing sounds. Similarly, differing interior surfaces  16   a  and  16   b  in chambers  10   a  and  10   b , respectively, create yet additional sound variation in the overall instrument.  FIG. 6G  demonstrates an instrument adding yet a third chamber  10   c  with additional balls  14   c  of a third size. Variable combinations of ball sizes and ball numbers possible, as well as varying internal surface textures can produce multiple sounds on the same instrument. 
     Alternative shapes of the overall instrument are employed in various embodiments such as bowl  11  or cup  13  shapes with one end plate  12  or various ellipsoids terminating in end plates or with curved terminations. Exemplary shapes for the instrument are shown in  FIGS. 7A-7D . A circular profile for the inner surface  16  of the wall having a sufficient radius allows the highly uniform spherical balls retained in the interior of the instrument to be accelerated into uniform circular motion represented by arrows  17  for the generation of persistent sound is shown in  FIGS. 7A and 7B . In the embodiments shown in  FIGS. 7C and 7D , the case incorporates a partial paraboloid profile  52  having an axis of symmetry coinciding with the axis of the circular profile  50 . 
     Additional complexity of sound may be created by interconnecting multiple separate instruments of the embodiments disclosed for simultaneous actuation.  FIGS. 8A-8D  demonstrate exemplary embodiments of this type.  FIG. 8A  is a consolidated or conglomerate instrument employing three cylindrical instruments as described with respect to  FIG. 1 . Each of the units has a case  10   d ,  10   e  and  10   f  carrying balls  14   d ,  14   e  and  14   f  having varying diameter and number. Interconnecting frame  54  attaches the three cases together. The embodiment shown in the drawings provides a handle  55  in one web of the frame, however, in alternative embodiments, the webs may be of identical shape.  FIG. 8B  shows a similar embodiment with three interconnected spherical instruments  56   a ,  56   b  and  56   c  each as previously described with respect to  FIGS. 3A and 3B  interconnected with a frame  58  having a handle  60 . As with the embodiment described in  FIG. 8A , the frame and handle arrangement may be altered to suit potential playing styles or usage. 
       FIGS. 8C and 8D  show an alternative embodiment employing four instruments of torroidal shape as described with respect to  FIGS. 2A through 2D . The torroidal cases,  10   g ,  10   h ,  10   i  and  10   j  are interconnected with a frame  62 . As described for the embodiments of  FIGS. 8A and 8B , the balls in the torroidal cases may be of varying size and number. Additionally, the material of the torroids may be different providing a highly complex sound from the instrument. 
     Having now described the invention in detail as required by the patent statutes, those skilled in the art will recognize modifications and substitutions to the specific embodiments disclosed herein. Such modifications are within the scope and intent of the present invention as defined in the following claims.