1.  Field of the Invention
This invention relates to music holders for music books, bound pages of music, and the like in which the leaves, when not held open, tend to close. 
2.  Description of the Prior Art
Music books are, as indeed are books in general, composed of a plurality of leaves held together at a spine by a suitable binding.  Usually, a music book is composed of a large number of signatures, a technical term by which a folded sheet is known.  It is customary, when making a music book, to arrange signatures in groups, for example, of eight folded sheets, which will thus constitute sixteen leaves, and then to stack the signatures so that the folded edges are registered, i.e. arranged in a common, approximately plane, configuration.  Thereafter, depending upon the manner of binding, the signatures are mutually secured to one another. 
In the so-called Smythe mode of binding, a line of stitching is run through a large number of signatures while the signatures are compressed together adjacent the spine. 
In the Perfect method of binding, a group of signatures is clamped together adjacent the spine and the fold lines are ground down to roughen the same, after which hot-melt glue is applied to the ground edges.  Sometimes wire stitching is used.  Sometimes wire stitching is applied through the fold itself. 
Regardless of which method is used to create the binding at the spine, the great majority of music books have a common characteristic, namely, the leaves of the book tend to assume an abutting, i.e. juxtaposed or face to face, relationship, one against another, when not manually held open.  If the music book is opened and then released, the pages of the book will close.  Of course, a music book can be forced to stay open as by cracking the spine, but this is harmful to the book and may shorten its life.  This method of handling ordinarily is not used. 
There are some books, that is to say, some methods of binding books, which are not subject to this self-closing drawback.  By this, reference is had to flat-opening books of which a stenographer's notebook with a spiral wire binding type is typical.  Another flat opening book is one in which the binding is a series of split interconnected rings formed of a single piece of wire.  Another flat opening type of book is one usually found in cook books and similar heavy books.  These employ plastic binders constituted of a thin plastic strip having outwardly extending arcuate arms that curve back upon one another and pass through openings in the leaves of the book. 
However, it is not customary to make music books with flat bindings.  It is far more usual to bind music books in such a manner that the pages will tend to remain closed.  Such books are more attractive and more popular wih musicians.  However, they present a certain difficulty in use.  This is that when the books are opened flat and placed with their front and back covers against the back of a music stand, the books will not remain open when released.  There are various ways in which the book can be forced to stay open, but none of them is acceptable. 
For example, the two halves of the book, not necessarily equal halves, can be clamped to the back of a music stand with spring clips, but this makes turning the pages difficult and also sometimes scratches the music stand, which is unacceptable when the music stand is a permanent part of a piano and is a highly finished piece of wood. 
Another way to make the music book stay open is to "break" the back.  However, this appreciably shortens the life of the book and is frowned upon. 
Another way is to have an assistant hold the music book open to turn the pages as required.  This obviously is a rather expensive procedure and, where an entire chorus in rehearsal or orchestra is involved, is impractical and unsightly. 
Thus, up to the present, there has been no practical, inexpensive item available on the market that will hold an ordinary music book open and permit the pages thereof to be turned with facility without damaging the book. 
Some holders have been proposed for books and the like.  Among these are the ones shown in U.S. Pat.  Nos.  55,897 of June 26, 1866; 2,373,617 of Apr. 10, 1945; 2,490,356 or Dec. 6, 1949; 3,606,235 of Sept. 20, 1971; and 4,199,125 of Apr. 2, 1980.  None of the foregoing permits ready turning of the pages.