US1664041A - Pneumatic action - Google Patents

Description

. March 27, 1928. 1,664,041

J. S. MAXWELL PNEUMATIC ACTION Filed Aug. 25, 1925 avwentoz J hn .5, Maxwell.

Patented Mar. 27, 1928.

UNITED STATES 1,664,041 PATENT OFFICE.

JOHN S. MAXWELL, OF RICHMOND, INDIANA, ASSIGNOR TO STARR PIANO COMPANY,

OF RICHMOND, INDIANA, A CORPORATION OF INDIANA.

PNEUMATIC ACTION.

Application filed August 25, 1925/ Serial No. 52,309.

This invention relates to pneumatic player pianos and similar musical instruments, and refers more particularly to valves for pneumatic actions.

The object of this invention is to produce a valve which is of light construction so as to be susceptible of having its position changed immediately whenever there isa variation of pressure on its diaphragm, and which will, at the same time, be capable of seating firmly on its seat even though its stem be inclined at an angle from the plane of the valve seat orthat the same is unlikely to be seated tightly for any other cause, such as, for example, an inclined valve seat.

The valve seats in the actions are pressed or threaded into place, and it is probable that some of these might not assume the exact true position intended, that is,'of having its seat in a horizontal plane perpendicular to the natural position of the valve stem. In such a case, if the valve and valve stem were rigidly connected, binding might result and the general efliciency of the instrument couldbe seriously afi'ected. Binding, however, would not occur in the usual case, but a lack of complete seatin of the valve on its seat might result, whicfiwould allow a leakage of air that would entail the expenditure of more power than should be necessary in the operation of the piano.

Heretofore, valves have been used that would allow for a universal adjustment and flexible connection between a valve stem and valve that would permit the valve to seat truly even though the seat be at an angle with the horizontal and the valve assume ing due to any rotary displacement, and it is part of my purpose of invention, as outlined above, to produce a simple form of valve capable of universal adjustment be tween the valve and valve stem with a minimum number of parts and amount of material which will possess the desired qualities of lightness and flexibility and be capable of effective sealing.

Other objects and uses of the invention will appear from a detailed description of the same, which consists in the features of construction and combinations of parts hereinafter described and claimed.

In the drawings,

Fig. 1 is a transverse fragmentary view of an action showing the valve in its normal position.

Fig. 2 is a pers ective view from the under side of the va ve.

Fig. 3 is a section of the valve and valve stem.

In Fig. 1 the valve is shown in its normal position in an action, and it comprises a disk or head 10 having a projection 11 extending from its upper surface and passing through a facing 12 of leather, fiber, or other suitable material. The lower face of the disk has raised from its center, or integral therewith, a button 13. To the lower face is glued or otherwise caused to adhere another facing 14.- which extends over and covers the button forming a smooth rounded rise at the center, Fig. 2. The stem of the valve may be of any design and the one which I have chosen to illustrate has a central portion 15 which has a cross-section of slightly greater area than the button on the disk, but it is desirableonly that these two features have approximately the same area. Four flanges 16 extend radially from the central portion 15 of the stem, but any other arrangement could be used. In assembling the valve and valve stem the central portion of the top of the stem is glued directly to the leather facing on the lower surface of the valve in such a position that the center of the button is in alignment with the axis of the stem. It is evident that, owing to the height of the button from the valve face and its hemispherical contour, the stem will be susceptible to being inclined in any direction from the perpendicular or, in other words, from a normal to the plane of the valve face.

Another essential and most desirable feature is to have some amount of flexibility and springiness between the stem and the valve as well as universal adjustment, and I have obtained excellent results in this direction by gluing the leather facing on the lower side of the valve at its edges only and not having any close adherence between the button or the face immediately surrounding the button with the facing. This condition allows for pivotal motion of the stem in respect to the valve without any tendency to cause a separation of the stem from the leather facing, Fig. 3. When the stem is at an angle with the valve the leather on one side of the button may be slightly lifted from contact with the valve face, but the main contacting glued area will not be disturbed.

I have used leather as a facing because of its excellent sealing qualities due to its pliability and consequent ability to settle and fill any irregularities in the valve seat, and also because it does away with the necessity of having any other cushion or resilient connection between the valve and the stem. The leather lends itself to such alternate stretching and compressing during the operation of the valve as it may be called upon to submit to, but I do not wish to be limited to this material since any other material capable of performing the same function could be used.

The valve is shown in its normal position on seat 17. When a hole in the music roll passes over the opening in the tracker bar related to any particular action, air is admitted to chamber 18 and the resulting unbalanced pressure on diaphragm 19 causes the valve to be raised so that its upper facing 12 contacts the valve cap 20 and closes the port 21 thereby shutting off communication with the atmosphere of passage 22 and causing the bellows to collapse and actuate the note striking arm in the manner well known in the art. 7

The diaphragm 19 comprises a normally dish-shaped member of light construction which may be made of rubber, fibre, leather, or of any other air tight flexible material. It has a flanged edge 23 which bears upon and is secured to ledge 24- and when the diaphragm is in a position'of rest, its central portion extends downwardly within a recess or chamber. To the central portion of the diaphragm is attached a pressure distributor or equalizer 25 in the form of a disk and preferably made from a single piece of material so as to insure rigidity and simplicity as well as lightness. At the center of the pressure distributor there is a rounded projection in the form of an indentation 26 the lowest extent of the outer surface of the projection of which is attached to the diaphragm by means of glue, cement, a pin, or

otherwise fastening. -The rounded surface allows for tilting movement in any vertical plane between the pressure distributor and the diaphragm so that the upper surface of the distributor will seek the plane of the lower end of the valve stem when the diaphiagm is raised by air" pressure. This action will occur even though the valve stem be very much inclined from its normal vertical position. In order to cushion the contacting effort of the valve-stem and pressure distrilimtor, a thin cushion 27 of soft fibrous material is secured to the pressure dis tributor at its center. It is-of larger dimension than the largest cross-sectional dimension of the valve-stem, and is suflicient-ly thin that a space remains between it and the valve-stem when the parts are in the positions illustrated in Fig. 1.

It is evident from the foregoing description that the connection between the valvehead and the valve-stem, and the relation of the valve-stem to the pressure distributor, and the connection between the pressure distributor and thediaphragm, are such as to insure perfect and instant operation of the pneumatic due to the universal adjustability of the valve parts, the lightness and simplicity of their construction, and their mechanically efliciont design which permits of complete seating and accurate registry of the. correlated parts.

These improvements are susceptible to variations in structure and shape, and I do not wish to be limited to the particular form described, for I contemplate the use of other suitable materials than those recited,-and such alterations and modifications as may be deemed expedient and coming within the scope of the appended claims.

What I claim is" 1. A valve comprising a head, a stem, and a resilient facing intermediate said head and stem, said head having a projection directly above said stem. I

2. A valve comprising a head having a raised portion at its center, a facing cut-ending over said raised portion, and a. stem. Elf". fixed to said facing opposite said raised portion.

3. A valve comprising a. head having a raised portion at its center, a facing extending over the surface of said valve and said raised portion, and. a stem afiined to the out or surface of said facing at a point opposite said raised portion.

l. A valve comprising a head having a raised portion at its center and integrally. therewith, a facing secured to the valve face around said raised portion and overlying said raised portion, and a stem affixed to the outside surface of said facing opposite said raised portion. r

5. A valve comp-rising a head having a raised portion, afacing affixed to the surface of said valve so as to allow parting-of said valve and facing at a. definite place, and a. stem secured to the outer surface of said facing opposite said definite place.

6. A valve comprising a disk having a substantially hemispherical button projecting from its surface, a facing extending over said button and surface, and a stem at fixed to said facing opposite said button, saidl stem having a. cross-sectional end surface of relatively greater area than said button.

7. A valve comprising a disk having-1a substantial hemispherical button projecting from its surface, a facing extending over said button and affixed to the surface around said button, and a stem. having one end affixed to said facing opposite said button whereby said stem may be tilted in respect to said disk.

8. In an action for player pianos, the combination of a valve comprising a head, a stem, a pressure distributor having a projection at its center, and a diaphragm secured to said pressure distributor.

9. In an action for player pianos, the combination of a. valve comprising a head, a stem, a facing connecting said valve and stem, a pressure distributor having a projection, a diaphragm secured to said pres sure distributor at the highest point of said projection, and means intermediate said stem and pressure distributor for cushioning the effort of impact.

10. In an action for player pianos, the combination of a valve, a button on said valve, a facing overlying said button and forming the sole connect-ion between said stem and said valve, and a diaphragm dis.- posed at the opposite end of said stem and spaced therefrom.

11. In an action for player pianos, the

combination of a valve, a stem flexibly connected to said valve, a diaphragm, a. pressure distributor flexibly connected to said diaphragm and spaced from said stem, the flexible connection permitting of relative rocking motion of said. disk and pressure distributor.

12. In an action for player pianos, the combination of a valve, a stem flexibly connected to said valve, a disk having a rounded projection integral therewith, a diaphragm secured to said projection so as to permit tilting between said diaphragm and said disk, and means on said disk for contacting the end of said stem.

13. A valve comprising in combination a head, a stem, an actuating diaphragm, and a disk spaced from said stem and independent thereof and secured to said diaphragm at a single point of less area than the area of said disk.

14. A valve comprising in combination, a

head, a stem, an actuating diaphragm, and a disk having a raised portion contacting said diaphragm, said disk being intermediate said diaphragm and! said stem and free from connecting relation with said stem.

In testimony whereof I hereto afiix my signature.

- JOHN S. MAXWELL.

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