Tone hole pad and process for magnetically seating same

A process for evenly seating a woodwind instrument tone hole sealing pad in the pad cup, and the pad assembly itself. The process contemplates placing the pad on the tone hole rim, applying a magnetic force to the pad to pull it against the tone hole rim, providing a substance between the pad and the cup for positioning the pad in the cup, and contacting the cup to the pad to position the pad in the cup while the pad is seated against the tone hole rim to provide an even seating cup pad assembly.

FIELD OF INVENTION 
This invention relates to a process for magnetically evenly seating a 
woodwind instrument tone hole sealing pad in the pad cup, and the pad 
assembly itself so that the pad properly seals around the entire 
circumference of the tone hole rim in use. 
BACKGROUND OF INVENTION 
In order for a woodwind instrument to have accurate sound, it is critical 
that the tone hole sealing pad make a complete seal flat against the tone 
hole rim. Since the tone hole rims are almost never perfectly flat, the 
pads are almost never perfectly flat, and the cup that holds the pad is 
almost never perfectly flat, the pads must be installed in the cup using 
shims behind the pad in order to get as close to a sealing fit as 
possible. The installation is made more difficult by the fact that the cup 
approaches the tone hole from an angle, making this shimming more guess 
work than science. 
There have been a number of techniques developed in attempts to provide 
relatively easy installation of pads that properly seal around the entire 
circumference of the tone hole rim. One method contemplates floating the 
pads into place on a liquid placed in the cup, which then hardens to serve 
as a permanent shim between the cup and the pad. In this process, while 
the pad is floating on the liquid, the installer pushes the pad against 
the tone hole rim by moving the cup down towards the rim. Ideally, the pad 
will seat flat against the rim and the liquid will harden, securing the 
pad in the position necessary in the cup to provide a flat fit of the pad 
against the rim. Typically, shellac is used as the liquid for floating the 
pad; the shellac is melted by the application of heat to the cup. Various 
other adhesives have also been used. 
This floating technique suffers from a number of problems. The larger pads 
for the woodwind instruments having larger tone holes are inherently more 
flexible than the smaller pads and thus are even more likely not to be 
flat. Since the traditional floating process relies primarily on pads 
being flat and rigid, the process does not work well for these large pads. 
Further, the pad installer must very carefully push the cup against the 
tone hole rim while seating the pad in the floating process, since there 
is really no effective way to pull the pad out of the cup once it is 
pushed into the cup. Sometimes the installer can stick a pin in the side 
of the pad and lever it back out of the cup, but this procedure can damage 
the pad skin, is imprecise, and can sometimes leave air bubbles behind the 
pad which allow the pad to collapse at this point in use. One method that 
has been developed to move the pad around in the cup while it is being 
installed in such a manner is to place a shim or slick between the pad and 
the cup under one section of the pad in order to compensate for some 
imprecision in the floating process. However, this requires that the 
operator perform educated guesswork, which is fraught with problems and 
also requires an experienced and thus expensive installer. 
For pads that are held in a cup with a screw and a washer, the pads are 
typically shimmed with extremely thin pieces of paper placed between the 
pad and the cup to push the pad forward so that it lies flat against the 
tone hole rim. This installation is typically accomplished by the 
installer first applying a single paper shim cut in a desired shape to 
match as closely as possible the pad to the rim. Then, the pad is pressed 
against the rim using the instrument keys. The installer can then use a 
feeler gauge or a light source placed inside the instrument tube to find 
gaps between the pad and the rim. The installer identifies and marks the 
location of the gaps, removes the key from the instrument, removes the pad 
from the cup, and then adds one or more shims to make up for the gaps. The 
pad is then placed back into the cup, the key is reassembled onto the 
instrument, and the pad closure is tested again with a feeler gauge or 
light source. The shimming process is repeated as often as necessary to 
accomplish the desired seating. 
This process suffers from the drawbacks that it is time consuming and 
depends on the judgment of the installer regarding the location and 
thickness of paper shims. Since this judgment is experiential, the 
installer must be skilled, and the process is therefore expensive. 
Further, the cup surfaces typically are not flat. Accordingly, over time 
the paper or plastic shims can collapse into the curve of the cup, 
destroying the flatness that is accomplished with the shims. Another 
problem with this installation technique is that it requires frequent 
replacement of the metal screws, washers and/or bushing which hold the pad 
in place. Since it is nearly impossible to accomplish such replacement in 
the same way twice, the installer may conclude that a pad is leaking 
because of improper shimming when in fact the placement or tension of the 
metal pad holder has altered the position of the pad. Finally, the metal 
pad holders amplify the noise of the pad striking the tone hole rim and 
are thus undesirable in good quality instruments. 
A third pad installation technique for felt pads contemplates securing the 
pads in the cups using metal or plastic pad holders that are clamped in 
place. Steam is then circulated through the body of the instrument to set 
the tone hole rim impression in the pad. However, this setting is 
impermanent and thus the pad will have a tendency to return at least 
partially to its original position, causing the pads to leak. Further, 
these felt pads are thick and fluffy thus have a spongy feel to the player 
which is undesirable because the player does not know exactly when the pad 
is in contact with the tone hole rim. Additionally, pads which can take a 
deep impression of the tone hole rim create more surface on which the pad 
can stick to the tone hole rim, making play difficult. The metal pad 
holders amplify the noise of the pad striking the tone hole rim, making 
them undesirable. Finally, since the technique requires steam, it cannot 
be used on instruments made of wood. 
SUMMARY OF INVENTION 
It is therefore an object of this invention to provide a pad installation 
technique that is extremely easy to use. 
It is a further object of this invention to provide such a technique which 
insures that the pad is seated against the entire circumference of the 
tone hole rim. 
It is a further object of this invention to provide such a technique which 
requires very little skill or experience and thus is relatively 
inexpensive to accomplish. 
It is a further object of this invention to provide such a technique which 
is much faster than existing techniques and is thus less expensive. 
It is a further object of this invention to provide such a technique which 
accomplishes a permanent relationship between the pad and the tone hole 
rim. 
It is a further object of this invention to provide such a technique which 
automatically accomplishes a proper and consistent pad protrusion from the 
pad cup after installation. 
It is a further object of this invention to provide such a technique which 
eliminates the need for metal holding washers, screws, and spuds thus 
reducing transmission noise of the pad striking the tone hole rim. 
This invention results from the realization that a simple yet extremely 
effective pad installation technique may be accomplished by applying a 
downward magnetic force to the pad while it is sitting on the tone hole 
rim and then placing a hardenable material in the cup and pressing the cup 
against the pad that is seated flat on the tone hole rim to secure the pad 
in the cup in this position. 
This invention may be accomplished in a process for evenly seating a 
woodwind instrument tone hole sealing pad in the pad cup. The process 
contemplates placing the pad on the tone hole rim, applying a magnetic 
force to the pad to seat it on the tone hole rim, and securing the cup to 
the pad, preferably by providing a substance between the pad and the cup 
for positioning the pad in the cup, and contacting the cup to the pad to 
position the pad in the cup while the pad is seated against the tone hole 
rim to provide an even seating cup-pad assembly. 
The pad is preferably positioned in the cup with a solidifiable liquid such 
as a silicone compound or shellac. The solidified material is preferably 
remeltable, such as is the case with shellac or a hot-melt glue, to allow 
subsequent adjustments should they be necessary. 
The magnetic force may be applied by attraction or repulsion, and may be 
accomplished with a permanent or electromagnet, and a 
magnetically-attractable material in or on the pad, for example a metal 
washer placed in or on top of the pad. Alternatively, the pad or the 
washer could be magnetic, and then seated with a magnetically-attractable 
material placed near the pad assembly. 
The magnet may be permanent or an electromagnet. It may be placed within or 
outside of the instrument, close to but not touching the pad. A spacing or 
holding device may be employed to maintain the spacing during pad seating. 
The pad assembly may include a pad and a magnetic or 
magnetically-attractable material in or coupled to the pad. This allows 
the assembly to be seated using magnetic force.

This invention features a method for installing a woodwind instrument tone 
hole sealing pad contemplating placing a magnetically-attractable pad on 
the tone hole rim and applying a magnetic force to the pad to seat it 
against the rim and then adhering the pad while seated on the rim in this 
fashion to the cup to provide a pad which seats flat around the entire 
circumference of the tone hole rim during play. Also featured is a pad 
assembly that is magnetically seatable. 
There is shown in FIG. 1 woodwind instrument such as flute 10 having a tone 
hole defined by tone hole rim 12. The tone hole is sealed with pad 18 held 
in cup 16 that is movable on and off of rim 12 by key assembly 14. 
Substance 20 which is preferably a hardenable liquid substance, is used to 
retain pad 18 in cup 16 in such a fashion that pad 18 seats flat around 
the entire circumference of the tone hole 12 and also so that pad 18 
protrudes slightly from cup 16 as shown as is desired in quality woodwind 
instruments. Pad 18 may be any of the known pad types such as silicone, 
plastic materials, cork, and/or felt. 
One embodiment of this invention is shown in FIG. 2A. In this process one 
secures a magnet 43 in the tone hole below the tone hole rim 12a, and 
relies on the magnetic attraction between the pad 18 and the magnet to 
create the force to hold the pad against the tone hole rim. The pad is 
made at least partially magnetically attractable by using a metal washer 
within or on the pad. See FIG. 3. For pads which are molded or made from 
synthetic material, magnetic material can be added to the pad material 
during manufacture to provide an attractable pad. There is thus no direct 
contact between the pad and the force-producing magnet. The magnet can be 
held in the tone hole through use of an o-ring 44, a "carrying arbor", or 
other devices for removably holding the magnet near the pad. One advantage 
of this technique is that the instrument does not have to be held 
perpendicular to the force of gravity, and can be handled while the pad is 
floated into the cup. Alternatively, the pad could be made magnetic and a 
piece of attractive material could be placed in the instrument to attract 
the pad. 
The method described above involves force-creating devices for each tone 
hole. Since there are sixteen or more tone holes on a typical flute, this 
can be cumbersome. An improvement on this is shown in FIG. 2B. One inserts 
a magnetic rod 44 into the entire body of the instrument 10 which is 
strong enough to exert force across the gap between the magnetic rod and 
the pad 18a. This magnetic force will pull all the pads 18a down against 
the tone hole rim 12a simultaneously. Each pad can then be floated into 
its cup 16 individually or all pads can be floated into place 
simultaneously. Ideally the magnetic rod will be an electromagnet so that 
the force can be varied or turned on and off, which will allow easy 
removal of the rod. Using this technique there is no need to disassemble 
the keys from the instrument to remove the force. It should be quick, 
neat, flexible, and accurate; it also requires little or no skill. 
Assembly of the cup to the pad assembly is completed by adhering the pad 
into the cup while the pad is in position on the tone hole rim. 
Preferably, this adhesion is accomplished with a hardenable liquid 
material such as a hot melt glue, a silicone compound or shellac, for 
example. The material is preferably placed in the cup in a liquid or tacky 
form and then the cup is seated down onto the pad. After the material 
hardens, the magnetic force is removed. 
The floating material is preferably a hot melt glue such as Jet Melt 
Adhesive Number 3792Q made by 3M Corp., St. Paul, Minn. This substance can 
be reliquified by the application of heat to allow the pads to be adjusted 
if necessary. The installer presses the cup with the floating material 
onto the pad until the pad protrudes the correct distance from the cup. 
If the pad is made of a material like wool felt which is likely to swell 
and/or shrink over time, an impression of the tone hole rim can be created 
in the pads by steaming and clamping to minimize the chances of future 
leaks around the pad-rim seal. 
FIG. 3 shows another embodiment of a pad assembly according to this 
invention. Pad 18a includes magnetic or magnetically-attractable material 
21 to allow the application of magnetic force to seat pad 18a on a tone 
hole rim. The force could be attractive or repulsive. As described, the 
material can be in or on, or coupled to the pad to provide a magnetically 
seatable pad assembly. 
Although specific features of the invention are shown in some drawings and 
not others, this is for convenience only as each feature may be combined 
with any or all of the other features in accordance with the invention. 
Other embodiments will occur to those skilled in the art and are within the 
following claims: