US2751805A

US2751805A - Piano tuning wrenches

Info

Publication number: US2751805A
Application number: US485539A
Authority: US
Inventors: Leftly Stanley Leonard
Original assignee: Individual
Current assignee: Individual
Priority date: 1955-02-01
Filing date: 1955-02-01
Publication date: 1956-06-26
Anticipated expiration: 1973-06-26

Description

June 26, 1956 s. 1.. LEFTLY 2,751,805

PIANO TUNING WRENCHES Filed Feb. 1, 1955 Z0 Z6 m 23 6Z 26 Fg g us D 210 I i' 152 zzmrwifl WWW United States Patent i PIANO TUNING WRENCHES Stanley Leonard Leftly, Toronto, Ontario, Canada Application February 1, 1955, Serial No. 485,539

3 Claims. (Cl. 84-459) This invention relates to piano tuning pin socket wrenches, which are generally known in the art as piano tuning hammers, and consists of a novel construction and arrangement of gears and linkage engaging a specially constructed wrench having the ordinary well known eight point star socket.

An object of the present invention is to provide a readily and quickly applied means of precise control over manually applied force-s necessary to regulate and adjust tension of musical strings on a pianoforte.

The above as well as additional objects will be clarified in the following description wherein characters of reference refer to like numbered parts in the accompanying drawing. It is to be noted that the drawing is intended solely for the purpose of illustration and that it is therefore neither desired nor intended to limit the invention necessarily to any or all of the exact details of construction shown except insofar as they may be deemed essential to the invention.

Referring briefly to the drawing,

Fig. 1 is a fragmentary perspective view of a piano showing the pin block with the tuning hammer of the present invention about to be applied to a pin to be tuned and another pin remote therefrom.

Pig. 2 is a front elevation view of the tuning hammer.

Fig. 3 is a top plan view of the tuning hammer.

Fig. 4 is a sectional view taken on the line 4-4 of Fig. 2.

Fig. 5 is a sectional view taken on the line 5-5 of Fig. 3.

Referring in detail to the drawing, the numeral indicates the pin block of a piano, having the tuning pins 11 mounted thereon in which the upper ends of the strings 12 are anchored and by turning which, as is well known, the strings are tightened or loosened as desired to be properly tuned.

The apparatus of the present invention is constructed as follows. A tubular socket wrench 13 having a standard eight pointed star socket 14 is adapted to be applied over and engage any of the tuning pins 11.

Rigid on the outer end of the wrench 13 is one end of a sector arm 15 having at its other end an arc of internally formed gear teeth 16 concentric with axis of Wrench 13.

Rigidly attached to one end of an elongated arm 17 is a stud held in pivotal engagement with the outer end of the tubular wrench 13, and hence with the sector arm 15, by a retaining pin 27.

The other end of the arm 17 is pivoted to one end of a link 18 by a pivot pin 21. The other end of link 18 is pivotaliy engaged to the outer end of a sleeve 19. The link 18 is preferably formed by bifurcating one end thereof so that the members 18a and 18b so produced engage opposite sides of the arm 17. The link 18, it is to be noted, is both slidably and pivotally secured to the sleeve 19.

As shown in Fig. 4 of the drawing the internal diameter of the sleeve 19 is reduced at the pin engaging end to 2,751,805 Patented June 26, 1956 form an internal flange 22a. The sleeve is also provided at the same end with an external flange 22, and at a point a suitable distance from the other end of the sleeve 19 a stop pin 23 is rigid with the sleeve; the link 18 being mounted between this pin 23 and the flange 22. A compression spring 24 surrounding the sleeve 19 between the flange 22 and the link 18 normally urges the latter outward on the sleeve against the stop pin 23.

With the link 18 in its outer extreme position on the sleeve and with the device applied for operation as indicated in Fig. 1, the arm 17 and the link 18 lie in a common plane parallel to the pin block 10.

Pivoted to the arm 17 and in mesh with the internally formed gear teeth 16 is a pinion 25 having an extended shaft 26 rigid therewith, the latter having its outer end of square section exactly similar to that of a standard tuning pin 11 so that the pinion 25 may be rotated, through the shaft extension 26, by means of an ordinary standard tuning hammer of the prior art or, alternatively, by any suitable key 29 as may be desired.

Since it is desirable, in order to avoid confusion in practice, that the effort arm of any tuning hammer be moved in the same angular direction as the pin to be tuned it is to be noted that as a result of the particular combination of the pinion 25 and the teeth 16 of the sector arm 15 in the present invention, an angular movement of the effort arm key 29 produces simultaneously a movement of the socket 14 in the same angular direction without interposition of an idler or compounding gear such as would otherwise be required. It is also to be noted that owing to the particular construction of the sector arm 15 of the present invention, a direct view of pertinent pins, strings and other parts, is available to the user of the device while normally seated in front of the piano to which the device is being applied.

Assuming that a pin 11, all of which are alike and square in cross section, is to be manipulated to change the tension on the string 12 attached thereto, the device is applied as follows:

With the pinion 25 in mesh with the teeth 16 at approximately the centre of the are formed by the latter, the socket 14 is applied over the selected pin 11 in such a position that the arm 17 extends across a portion of the pin block 10 and that the link 18, and hence the sleeve 19 may be swung radially about the pivot 21 in one direction or the other over one or more of the other tuning pins 11 remote from the selected pin. With the arm 17 and the link 18 angular-1y disposed each to the other as nearly as may be as indicated in Fig. 1 of the drawing, and with the sleeve 19 pulled outwards against the spring 24 and in alignment with a remote pin 11a, upon release of the sleeve it will be forced by the spring 24 over the pin 11a so that the internal flange 22a will be positioned relatively close to the base of the pin 11a.

Since, however, because of the eight point form of its socket 14, the wrench 13 is fittable over any pin 11 only in eight circumferential positions and because the facets of the squared ends of all such pins 11 on a piano are not uniformly orientated, the link 18 and the arm 17 are of such length that the device may be applied as described with a minimum of relative movement of the arm 17 to the sector arm 15 and hence a minimum rotation of pinion 25. The device, therefore, may be readily and quickly applied to the

appropriate pins

11 and 11a without regard to the orientation of the facets thereof.

The exact step by step procedure of applying the device to the tuning pins is, of course, of no consequence to the invention and some may do it one way and others in another way. The essential thing is to apply the device with the wrench on the pin to be tuned and the sleeve on a suitably positioned distant pin. It is to be noted that the device may be applied so that a pin 11a is either on the right or on the left of a pin 11 selected for tuning, as may be convenient to avoid obstructions such as, for instance, the side of the piano casing, frame ribs, and the like.

With the device so mounted, turning of the pinion extension 26 by means of a common tuning hammer or suitable key 29 will, through the pinion 25 and the internaily cut teeth 16, swing the arm 15 thus turning the selected pin 11 engaged by the wrench 13 to tense or loosen the string 12 thereon.

Since the

linkage

17, 18 is supported at three points which, it connected would form a triangle, that is, the axis of the pin in the socket 14; the pivot axis between the arm 17 and the link 18; and the axis of the remote pin limit is obvious that the linkage is rigid and immovable. However, the linkage tends to apply a force on the pin 11:: through the sleeve 19 in the nature of a moment tending to bend the pin, upon which the sleeve registers, at its base. If the sleeve 19 did not have the reduced opening provided by the inner flange 22a, the consequent tilting of the sleeve 19 would cause the inner wall thereof to make contact with the tip of the pin 11 11 and tend to bend it. This effect is reduced to a minimum by engagement of the pin 11a with the inner flange 22a much closer to the base of the pin, and the fact that the c inner wall of the sleeve does not make, contact with the pin.

The remote pin 11a on which the sleeve registers serves merely to create an equilibrant force component when applying torque on the pin 11 within the socket 14, and owing to the engagement of the pin 11a with the flange 22a as just mentioned, the possibility of putting the string of the remote pin out of tune after it has previously been tuned, is minimized.

The great ratio between the pitch radii of teeth of pinion 25, and sector arm teeth 16 of course offers a mechanical advantage so that a proper torsional force is applied to the pin being tuned, with a minimum elfort on the part of the user in turning the key 29. Consequently a very precisely controlled variation of tension of the relevant string 12 is possible to ensure a fine degree of tuning.

Obviously modifications of the form or structure may be made without departing from the spirit or scope of the invention.

I claim:

1. A piano tuning device adapted to turn in either direction any one of the tuning pins of the pin block of a piano, comprising a socket wrench adapted to engage axially the pin to be turned, a sleeve adapted to be fitted over a second pin remote from the pin to be turned, said sleeve having a reduced opening in the base thereof the wall of which opening is engageable with the pin at a point distant from the tip of the pin, a linkage having one end pivoted to said wrench and having the other end thereof pivoted to said sleeve, an internally toothed sector gear coaxial and rigid with said wrench, a means for turning said sector gear, said sleeve having an external flange on its base extending outwardly from the sleeve and a limit stop longitudinally spaced from the flange, a compression spring surrounding said sleeve between said flange and said stop, said other end of said linkage being additionally slidable on said sleeve and positioned between said spring and said stop whence said spring normally urges said other end of the linkage outward toward said stop.

2. A piano tuning device adapted to turn in either direction any one of the tuning pins of the pin block of a piano, comprising a socket wrench adapted to engage axially the pin to be turned, a sleeve adapted to be fitted over a second pin remote from the pin to be turned, said sleeve having a reduced opening in the base thereof the wall of which opening is engageable with the pin at a point distant from the tip of the pin, a linkage having one end pivoted to said wrench and having the other end thereof pivoted to said sleeve, an internally toothed sector gear coaxial and rigid with said wrench, and means for turning said sector gear, said linkage comprising an elongated arm extending from said one end thereof and a link extending from said other end thereof, said arm and said link having their juxtaposed ends pivoted together, said sleeve having an external flange on its base and a limit stop longitudinally spaced therefrom, a compression spring surrounding said sleeve between said flange and said step, said other end of said linkage and hence of said link being additionally slidable on said sleeve and positioned between said spring and said stop whence said spring normally urges said link outward toward said stop.

3. A piano tuning device adapted to turn in either direction any one of the tuning pins of the pin block of a piano, comprising a socket wrench adapted to engage axially the pin to be turned, a sleeve adapted to be fitted over a second pin remote from the pin to be turned, said sleeve having a reduced opening in the base thereof the wall of which opening is engageable with the pin at a point distant from the tip of the pin, a linkage having one end pivoted to said wrench and having the other end thereof pivoted to said sleeve, an internally toothed sector gear coaxial and rigid with said wrench, and means for turning said sector gear, said sleeve having an external flange at its base and a limit stop longitudinally spaced therefrom, a compression spring surrounding said sleeve between said flange and said stop, said other end. of said linkage being additionally slidable on said sleeve and positioned between said spring and said stop whence said spring normally urges said other end of the linkage outward toward said stop, said means comprising a pinion rotatably mounted on that end link of the linkage which is pivotally attached to said wrench, said pinion being in mesh with said internally toothed sector gear, and means for rotating said pinion.

References Cited in the file of this patent UNITED STATES PATENTS