US2141765A - Piano mechanism - Google Patents

Description

Dec. 27, 1938. J SAUERLAND 2,141,765

PIANO MECHANI SM Filed Jan.' 19, 1937 25 l A i I M4 54 26 5 6 10 19 20 a INVENTOR. W Z SQMLZML ATTORNEY 5 Patented Dec. 27, 1938 UNITED STATES PATENT OFFICE PIANO MECHANISM Application January 19, 1937, Serial No. 121,268

5 Claims.

This invention relates to pianos of the socalled miniature type wherein the keyboard is at or near the top of the piano and the action, which is of the upright type, is wholly or for the most part located below the keys and in front of the string-frame. In pianos of this type one of the primary objectives is to reduce the size of the instrument, particularly its depth from front to back, while maintaining a good touch and standard touch depth.

The depth of a miniature" upright piano is determined very largely by the length of the keys. The soundboard, string-frame, strings and action together require relatively little depth but a key with a good touch, proper touch depth and constructed in the conventional manner with its pivot at or near its midpoint is so long as to require a case of considerable depth. In a frontaction piano having such keys, the space required is so great as to preclude their use from a practical standpoint. Resort has been had, therefore, on the one hand to disposing the strings and associated parts centrally in the case, reversing the plate and placing the action in the rear. On the other hand the key mechanism has in some cases been condensed, as shown, for example, in the Nylund Reissue Patent No. 20,382. These expedients have had certain disadvantages, however, with respect to convenience, limitations of design and the ease of making and the permanency of adjustments. The present invention is directed to the elimination of these disadvantages.

The primary object of this invention is to provide key mechanism for operating the action of a front action piano of the miniature type, as herein defined, which occupies a minimum of space and yet has a touch comparable to an instrument with the conventional balanced type key, which has standard touch depth, is very accessible for adjustment, does not interfere with access to the tuning pins and which has no tendency itself to get out of adjustment.

Further objects are to provide key mechanism which may be inexpensively manufactured and easily assembled and adjusted. Other objects and advantages will become apparent in the course of the following description of the present preferred embodiment of the invention, in conjunction with the drawing in which:

Fig. l is a plan view of a portion of a keyboard;

Fig. 2 is a side elevation, partly in section, showing an action and its associated key mechanism and other related parts.

Referring to the drawing, at the front of the piano (on the left in the drawing) is the front rail 5 which extends across the instrument in front of the keys and between the sides, one of which is shown in part at 6. At the rear of the piano is the usual iron string frame 8 carrying strings 9 each of which is struck by a hammer 10. A standard upright action of the under-damper type is indicated generally by l I, certain detailed parts being omitted. The action includes the usual wippen I2, the lifting of which operates the action in known manner. The series of individual actions is mounted on a rail 14 which is supported at each end by an end piece l5 pivotally mounted by a screw 16 to an extending bracket on the frame 8.

The key mechanism is supported in a bed comprising the front rail 18, a center rail 19 and a rear rail 29, all of which extend the length of the piano. These rails may be braced at intervals throughout their lengths by metal braces 21, which serve to maintain the relative positions of the rails and prevent warping.

The key proper consists of a lever of the second kind, which is a lever having the load between the fulcrum and the power. The keys 22 and 23 are pivotally supported at their rear ends by hinge-brackets 24 fastened by screws 25 to the rear rail 20. The rail 20 is provided with a: tongue 26 which cooperates with grooves in the brackets 24 in the usual way. The length of the key 22 may be about the same as the length of the forward arm of a standard key of the balanced type, which means that it would be only about half as long as the usual balanced type key. The key is guided at its forward end on the pin 28, surrounded by the felt cushion 29. It has the standard depth of touch of about inch or 10 mm.

Beneath the key is an auxiliary lever 30 pivotally mounted in a bracket 3| secured to the rail 19 in any suitable way as by a screw 32. A strip of felt 34 provides a cushioned support for the rear arm of the lever 30 and fixes one limit of its travel. The said rear arm is provided with a felted notch 35 in which is inserted the hooked end of a pull member or rod 36. The rod 36 extends downwardly through a hole in the wippen l2 and is adjustably secured therein by the nut 38 which is screwed on the threaded lower end of the rod.

To the forward end of the lever 30 a button 40 is secured by means of a screw member 41 so that it may be adjusted for height. The button 40 bears against the under side of the key 22. The downward pull of the wippen [2, rod 36 and the rear arm of lever 36 is sufficient to counterbalance the weight of key 22 and support it in raised position. The parts are so proportioned that a pressure of about 2 ounces is required to depress the key 22, which is correct for a good touch. Furthermore the lever 30 has a slight multiplying factor so that the wippen is lifted by approximately the same amount that the front end of the key is depressed.

It will be noted that the under side of the key is hollowed out and that the pivot 42 for lever is positioned approximately in the same horizontal plane that passes through the point of contact between the button 46 and the key. By this arrangement the sliding of the button against the key when the parts are moved is minimized. The bottom of the key may be coated with dry graphite to further reduce any tendency to drag.

The arrangement of parts just described is one which makes adjustment of the piano unusually simple. The nuts 38 are all easily accessible across the front of the action upon removal of the front panel (not shown). By them the effective len th of the rods and the maximum and minimum positions of the wippens are adjusted. The key level and depth of touch are adjusted by turning the screws 4 I, which are easily reached from underneath the keybed. Inasmuch as the lever r sts on the felt 34 when in normal position, the key level is positively determined and stays in adjustment. The shortness of the keys, furthermore, provides ample space for access to the tuning pins 44 without increasing the depth of the piano.

Various modifications of the embodiment d scribed above may be made without departing from the spirit of the invention. It is therefore intended that only such limitations shall be imposed as are contained in the appended claims.

What is claimed is:

1. In a piano, in combination, a key consisting of a lever of the second kind pivoted at its rear end, a lever of the first kind mounted beneath the key, a button mounted on the forward arm of said lever so as to abut the under side of the key, means for adjusting the height of the button, an action having its wippen below the said lever, and a pull member connecting the rear arm of said lever with the wippen.

2. In a piano, in combination, a key consisting of a lever of the second kind pivoted at its rear end, a lever of the first kind mounted beneath the key and having its fulcrum nearer to its front than its rear end, a button mounted on the forward arm of said lever so as to abut the under side of the key, means for adjusting the height of the button, an action having its wippen below the said lever, and a pull member connecting the rear arm of said lever with the wippen.

3. In a piano, in combination, a key consisting of a lever of the second kind pivoted at its rear end, a lever of the first kind underneath the key and extending parallel thereto, a fixed pivotal support for said lever, means for supporting the rear arm of said lever, a button mounted on the forward arm of said lever and abutting the under side of the key, means for adjusting the height of the button, an action having its wippen below said lever, and a pull member connecting the rear arm of said lever to the wippen.

4. In a piano, in combination, a key fulcrumed at its rear end, a lever of the first kind pivotally l mounted beneath the key, a button carried by the forward arm of the lever and supporting the key, a support for the rear arm of the lever, means for adjusting the height of the button when the said rear arm is against its support, a pull member attached to the rear arm of the lever, the arms of said lever having such a ratio that said pull member is raised substantially the same distance that the front end of the key is depressed.

5. In a piano, mechanism for imparting motion to the action comprising a key fulcrumed at its rear end, a lever of the first kind beneath the key, a button carried by the forward arm of the lever and in contact with the bottom of the key, a support for said lever including a pivot, said pivot being in or near the horizontal plane passing through the point of contact between the key and the button, whereby sliding at said point is minimized, and a pull member adapted for connection to the action and attached to the rear arm of the lever.

JOSEPH SAUERLAND.

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