Patent Application
20180204552
A keyboard percussion instrument such as a marimba or vibraphone comprises a plurality of keys that are held in a frame. A user wields at least one mallet, striking various keys to produce musical sounds. When struck, each key produces a fundamental frequency that depends on the length of the key. The keys are supported in the frame in such a way that, when they are struck with an impulsive force, the ringing sound made by striking a key can last for a period of seconds. A user typically wishes to control, i.e., shorten, the duration of the ringing sound. The ringing sound is shortened with the use of a damper bar. A damper bar comprises an assembly including a rigidly supported felt strip or other material that is urged against one or more keys by a foot-pedal-controlled mechanism. To make a musical sound, a user presses a foot-pedal downward, removing the damper bar from contact with the keys. The user then strikes the top surface of a key with a mallet, causing the key to vibrate or ring. When the user wishes to stop the ringing sound, the foot pedal is released, urging the damper bar back into contact with the underside of a key to dampen the ringing sound.
In general, it is desirable for a damper bar to contact all the keys of an instrument simultaneously. This permits a user to dampen the ringing of all keys at the same time. Some users may want other scenarios, such as damping the treble keys first followed by the bass keys, or vice-versa. In the past, adjustment of the damping mechanism to obtain these three damping styles, i.e. all keys simultaneously, treble first, and bass first, required tools or even bending of parts of the mechanism that supported the damper bar. The need for using tools or bending parts of the damping mechanism prevented rapid adjustment of the damping mechanism, as is sometimes desirable between pieces of music during a musical performance. For example, a first musician may prefer uniform damping of all keys when the damping mechanism pedal is released, and a second musician, who is playing in the same musical set, may prefer damping bass keys first. In the past, it was impractical to accommodate the styles of both musicians during a musical performance. Even during normal maintenance of an instrument, the use of tools and bending of mechanical parts to adjust damping were at best inconvenient.
Stevens, in U.S. Pat. No. 8,049,089 B2 (2011) shows a keyboard percussion instrument having a damper bar. Stevens's damper bar is urged against the underside of his keys in response to the motion of a foot pedal and lever mechanism. Stevens provides the above three damping scenarios, i.e., damping all keys simultaneously, or progressively damping keys from one end of an instrument to the other, however he requires the use of tools to accomplish this.
Stevens provides two methods for adjusting and selecting damper bar performance through two damper bar mounting designs. In a first design, a damper bar (322 in
In a second design, two fastening elements (339a, 339b in
While Stevens provides adjustment of the damping bar to accomplish various damping scenarios, his system does not lend itself to easy and fast adjustment. I.e., it is necessary to somehow access fasteners (339) from within the end of his damping bar (322). This adjustment may need to be repeated after long use of the instrument. Thus it is difficult and awkward if sequential users of an instrument had different damping preferences. In either case, it is necessary to use tools and reach into the structure of the instrument to make the required adjustments between users.
I have discovered a method and apparatus that allows rapid adjustment of the height of a damping bar with respect to the underside of the keys in a keyboard percussion instrument. The height of the damping bar is independently adjustable at both ends, thus allowing selection of all three damping scenarios, i.e., all keys at once, the treble keys first, or the bass keys first. My mechanism independently supports each end of the damping bar and the height at each end is independently adjustable with thumbscrews, i.e., no tools are required. My apparatus is easily reached and quickly operated without reaching into the structure of the instrument with tools. The same adjustment of the damper bar location can be achieved by using one height adjustment mechanism at either the bass end of the instrument or the treble end instead of allowing the adjustment at both ends.
A plurality of keys 130A, 130B, and 130C rest on a plurality of supports 135A, 135B, 135C, and 135D. Only three keys and portions of four supports are shown in this view. In practice, there are two full rows of keys and two sets of supports. The keys are arranged with lower notes near a bass end and higher notes near a treble end of instrument 100. When the top side of any key is struck with a mallet or other object, the key vibrates and produces audible sounds.
A movable damper bar 140 is positioned so that the top surface of bar 140 is springably urged by a spring 1010 (
A foot pedal 145 is pivotally secured to cross member 120 by an arm 150 and a hinge 155. A connecting member 160, such as a rod, chain, rope, or strap, is secured to arm 150 at a first end and damping bar 140 at a second end. Pedal 145, arm 150, hinge 155, and connecting member 160 are normally positioned at the center of damper bar 140.
A pair of pivot arms 165L and R are secured to damper bar 140 at a first end. The second end of arms 165L and R terminate in pivot holes 170L and R, respectively. Pivot holes 170L and R are joined to pivot height adjusting mechanisms 175L and R. Pivot arms 165L and R are made of metal, plastic, reinforced plastic, or wood. These components are described in more detail below.
Damper Bar and Pivot Arms—
A bottom layer 205 of bar 140 is made of a rigid material such as metal, hardwood, or reinforced plastic. Layers 200 and 205 are securely attached to one another by adhesive or other fastening means.
Pivot Height Adjusting Mechanisms—Construction—
A cover plate 550 contains at least two holes 555 and 560 to permit the passage of a tightening thumbscrew 565 and a hinge-point screw 570 through holes 555 and 560 and into holes 545A and 545B (
Body 500 and post 520 of mechanism 175 are made of metal, reinforced plastic, or hardwood. Nut 515, screw 505 and cover plate 550 are made of metal, although other materials can be used. Screws 565 and 570 are made of metal, although other materials can be used. Thumbscrews 510 and 565 have knurled finger grips to permit fingertip adjustment.
Pivot Height Adjusting Mechanisms—Operation—
Pivot height adjusting mechanism 175 is operated by first loosening thumbscrew 565 as shown in
Pivot Height Adjusting Mechanisms—Installation—
Pivot Height Adjusting Mechanisms—Operation—
Normally damper bar 140 is urged upward by spring 1010 so as to prevent any key from ringing when it is struck by a user with a mallet. When pedal 145 is pressed downward by the user's foot, connecting member 160 urges damper bar 140 downward, away from contact with keys 130A, B, C, etc. in order to permit ringing of any key that a user strikes. Fixture 1005, spring 1010, and screw 1015 are normally located at the center of damper bar 140.
In the prior art, the pivot points on damper bar arms were not readily adjustable. It is necessary to adjust these in order to ensure proper operation of the damping mechanism. I.e., damping of all keys simultaneously, or damping of the bass or treble keys first as may be required by a particular user. In some cases, the arms that supported the damper bar were manually bent to accommodate these preferences. The present apparatus permits adjustment of the damping mechanism through manual turning of thumbscrews. Thus this adjustment can be done quickly, without bending internal parts of an instrument, and without the use of tools.
The pivot points can be set at equal heights with respect to the damping bar, or they can be set at unequal heights. When the pivot point at the treble end of an instrument is higher than that at the bass end of the instrument, high notes at the treble end are damped before those at the bass end when the damping pedal is released.
Steps in Adjusting Pivot Points.
The following steps are used to adjust the height of pivot fasteners 800L and 800R, and therefore the pivot points of arms 165L and 165R. This adjustment is made when it is desired to take control over the damping of sounds produced by a keyboard percussion instrument. The adjustment is used to fine-tune operation of the damping mechanism, as described above, i.e., when it is desired to cause all keys to be damped simultaneously, or to be damped at one end of a keyboard before the other end.
I have devised an improved method and mechanism for adjusting the damping of musical sounds emitted by a keyboard percussion instrument after a key has been struck. This is accomplished by adjusting the height of pivot points of a damping bar in a keyboard percussion instrument. My mechanism requires no tools; instead the user makes all adjustments manually using thumbscrews. The thumbscrews are easily reached from outside the instrument so that the height of the damping bar pivot points can be rapidly adjusted, i.e., between musical performances or between music pieces. A pivot point at one end of a damping bar can be fixed in position, while the pivot point at the opposite end of the damping bar is adjustable.
Instead of manually urging thumbscrews to raise and lower the pivot point, an electric or pneumatic motor can be used. While the examples discussed relate to marimbas and vibraphones, the principles of my system apply to all keyboard percussion instruments that employ damping of vibrations that have been induced in vibrating parts including keys, bars, and even strings.
Thus the scope should be determined by the appended claims and their legal equivalents, rather than the examples and particulars given.
