US1985746A - Piano construction - Google Patents

Description

Dec. 25, 1934. B. K, SETTERGREN PIANO CONSTRUCTION Filed May 25, 1954 MI W m N m T T A Patented Dec. 25, 1934 UNITED @FFEQE 3 Claims.

This invention relates to improvements in piano construction, and the object thereof is to provide a piano frame with members so arranged as to eliminate contraction and expansion thereof and to rigidly support the sounding board to thereby increase the endurance of the tuning of the piano and improve its tone quality by elimination of vibration in the frame members.

An illustrative embodiment of the invention is shown in the accompanying drawing, in which:-

Fig. l is an isometric View showing the bottom side of a piano frame to which the invention is applied; and

Fig. 2 is a fragmentary bottom plan view of the bracing structure.

In the illustrations is shown a piano frame constituted of an inner rim 1 which is connected at its forward ends by a cross-bar 2, and outer rim 3 is disposed upon the exterior of the inner rim as in the usual piano frame structure. A sounding board 4 provided with ribs 5 is secured about its margin to the top of the inner rim and the cross bar as in the usual manner.

A series of struts 6, 7 and 8 spaced. apart positioned in the piano frame so as to extend preferably in parallel relation with each other from the cross bar at right angles thereto and terminate respectively at their opposite ends against the inner face of the inner rim. to which their corresponding ends are secured.

The struts 6 and 7 have disposed. therebetween spacers 9 and 10 by which said struts are held definitely apart at points suitably distant from their ends. Upon the outer faces of the struts 6 and 7 are disposed anchor plates 11 and 12 preferably of metal, the ends of which plates are connected through the'struts by cor esponding tie rods 13 and l l provided with threaded nuts 15 which when tightened causes the struts to become bound tightly against said spacers.

A pair of anchor rods 16 are arranged in axial alinement with each other and extend through the struts G and 7 and complemental anchor plates ll and 12 at points preferably midway between the spacers 9 and 10 and are provided with threaded nuts 17 and 18 disposed respectively against the corresponding outer faces of the anchor plates and the inner faces of the complemcntal struts.

The outer ends of the anchor rods have cross heads 19 that are firmly secured to the inner rim structure of the piano frame by means of bolts 20 so that upon adjustment of the nuts 17 and 18 on the anchor rods 16 a definite spaced relationship between the inner frame and the struts 6 and 7 is established and the frame and struts are held securely against relative vibration. Also, in thus securing the inner frame and struts firmly together by means of the anchor rods, and holding the struts 6 and 7 firmly in position with respect to each other the sounding board is thereby sustained in a definite state of fixation about its margin whereby the initial crown of the sounding board is substantially preserved.

I claim:

1. In a piano construction, a frame having inner and outer rims and a cross-bar connecting the end portions of said inner rim, a sounding board secured about its margin to said frame, a series of struts spaced apart disposed in the frame extending respectively from the cross-bar to corresponding opposite points on the inner rim, a pair of spacers positioned between two of said struts, tie rods applied to the said two struts so as to compress the spacers therebetween, and an anchor rod for each of said two struts secured adjustably at one of its ends to the corresponding strut, said struts being axially alined with each other wnd connected at their other ends respectively to said frame at corresponding opposite points thereon.

2. in a piano construction, a frame having a and a cross-bar conn cting the end portions thereof. a sounding board secured about its margin to said frame, struts spaced apart extending respectively from the cross-bar to corresponding opposite points on the frame, space-rs positioned between said struts, an anchor plate on the outer face of each strut opposite said spacers, tie rods connecting said plates through said struts disposed so as to compress said spacers between said struts, and axially alined anchor rods adjustably connected with said struts at their inner ends respectively at points between said spacers and connected at their outer ends respectively to said frame at cor esponding opposite points thereon.

3. In a piano construction, a frame having a rim and a cross-bar connecting the end portions thereof, a sounding board secured about its margin to said frame, struts spaced. apart extending respectively from the cross-bar to corresponding opposite po nts on the frame, spacers positioned between said struts, tie rods connecting said struts at points adjacent said spacers disposed so as to compress said spacers between said struts, and axially alined anchor rods adjustably connected with said struts at their inner ends r spectively at points between said spacers and con nected at their outer ends respectively to said frame at corresponding opposite points thereon.

13303 K. SETTERGREN.

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