GB2368711A - Stabilised tremolo bridge - Google Patents

Abstract

A tremolo device for a stringed musical instrument which will maintain the tuned state of the remaining strings if one string is "bent" or in the event of the failure of one string. The device has a fixed plate 1 which is screwed to the body of the instrument, the rear edge of the plate with respect to the neck of the instrument being a knife edge of 'V' shaped cross-section across its whole width. This knife edge co-operates with a recess in the face of a string plate 2, such that the string plate 2 can pivot about the knife edge in the vertical plane. The ends of the strings remote from the tuning pegs of the instrument are secured in recesses in the string plate 2. Counterbalancing springs 6 act on the string plate 2 against the tension of the strings. Means to adjust the tension of the counterbalancing springs 6 is provided, comprising a screw 3 which passes through an aperture near the base of the string plate 2 and co-operates with the threaded hole of an adjusting bar 4. The counterbalancing strings 6 are attached to the adjusting bar 4 at one end and the fixed plate 1 at the other. The flat inner face of the head of the screw 3 acting against the flat face of the string plate 2 tends to maintain the tuned state of the remaining strings if one string breaks. The device does not require a locking mechanism.

Description

FIELD OF THE INVENTION This invention pertains to any stringed musical instrument and, more precisely, a mechanism for producing a tremolo effect in a stringed musical instrument.

BACKGROUND OF THE INVENTION The earliest method of obtaining a tremolo effect was to apply pressure on a string with a finger. This would raise the pitch of the string (strings) and, by varying the pressure rhythmically, a tremolo sound is produced.

Many types of mechanical device have been utilised in the prior art to achieve a tremolo effect, most of which permit all the strings on the instrument to have the pitch raised or lowered from the main tuning and, upon release of the mechanical device, the strings will return to the main tuning.

Mostly these devices involve moving the string anchoring tail piece about a pivotal point and are generally spring assisted to overcome the string tension and bring the strings back to their original pitch. An arm or handle is usually attached to the device to enable easy operation while playing the instrument. The device on guitars or bass guitars is normally located on the instrument body at a point of string termination or anchorage.

One of the main problems with prior art tremolo devices is that since the devices all utilise balanced forces about a fulcrum the tuning of the instrument is therefore very difficult and requires many retunings until correct pitch is achieved. At this point a stable state exists as long as no string goes off pitch or breaks to unbalance the forces about the fulcrum allowing the return springs to now have greater tension than the remaining strings. (We are assuming that the instrument has more than one string. ) Hence increasing all the remaining string's tension and therefore raising their pitch.

Another problem encountered by all prior art tremolos is similar to the above paragraph but in reverse. If in the course of playing the instrument a note is played, and the string being played is bent by finger movement, not by operation of the tremolo device, in order to raise its pitch, then the total tension of the strings increases. This means that the string tension is now greater than the return spring tension and these will stretch allowing the tremolo device to move until equilibrium is again obtained. This allows the pitch of the other strings to decrease while the single bent note of higher pitch has been obtained at the sacrifice of the original pitch of the remaining strings. This is not such a loss if only one note is required even though the string will need pushing harder to obtain the higher pitch note as the tremolo device is moving to maintain a steady state and only when the spring tension has been increased sufficiently to allow the strings tension to increase will the desired pitch of the string be achieved. On an instrument not fitted with a tremolo device all the strings are anchored individually and less force and time will be required to bend a note to a higher pitch as the movement of one string has no effect on the other strings. If a chord is played, ie; two or more strings are played at once, and a single note of the chord is bent with a prior art tremolo fitted to the instrument, the whole chord will keep lowering in pitch until the note being bent has reached the desired pitch.

One prior art tremolo device, the Steinberger Tremolo, Patent number 4,632, 005 USA did try to avoid many of the above problems by locking the tremolo device, rendering the device inoperative. When the device was unlocked it operated in exactly the same way as all other prior art tremolo devices using a balanced system.

The primary object of the invention is to overcome the above problems and this will be shown in the following description.

SUMMARY OF THE INVENTION This device is designed to be mounted onto the body of a stringed musical instrument, the musical instrument will normally consist of a body and a neck. The neck is attached to the body at one end. One end of each string is attached at the end of the neck which is not attached to the body by means of tension adjusting devices usually called machine heads. There can be any number of strings on the instrument. The other ends of the strings are anchored to the body of the instrument by means of a device called a bridge, and this invention is one such device. The objective of the tremolo bridge is to lower or raise the pitch of the strings attached to it. These strings are tensioned by means of the machine heads mentioned earlier until a desired pitch or range of pitches is achieved and by operation of the bridge this tension can be increased or decreased, within limits, as desired by the player of the instrument.

This is nothing new and has been achieved many times before by various type of tremolo bridge. Another objective is to enable the remaining strings to stay in tune should one string break or be"bent"during playing of the instrument. All previous systems have achieved this by some form of locking device incorporated into the bridge. The problem with this is that when the locking device is engaged it effectively prevents the tremolo device from operating fully. This invention is a bridge designed to achieve the aforementioned objectives and still remain in full operation.

To explain how these objectives are achieved references will be made to the illustration of operation and exploded drawings, but first here is a list of the various components of the device.

1; Fixed plate-screwed to the body of the instrument, it has a full width knife edge along one edge, plain edges at right angles to the knife edge, a plain edge opposite to the knife edge in which a recess is machined and in that recess are drilled several holes for the purpose of attaching ends of springs, several drilled and threaded holes for the purpose of attaching items known as"saddles"over which strings pass and bear on, and holes, normally two, for mounting the plate onto the body of the instrument.

2; String plate-this plate has a groove along one of its edges as shown, into which the knife edge of plate 1 locates. Lower down this edge is a hole, the internal profile of which is conical for a certain distance then relieved to allow space for a bolt head. Above the knife locating groove are holes drilled at an angle through the plate. Through these holes the strings of the instrument pass. There is a recess in each hole to locate the balls attached to one end of each string. Two holes are drilled and threaded vertically in relation to the top of the plate to enable an operating arm (mentioned later) to be screwed into either hole.

3; Adjusting screw-this adjusts the tension of the counterbalancing springs. The head of the screw is the means by which the operation of the invention is stabilised.

4; Adjusting bar-This is a bar with a threaded hole bored and threaded at right angles to its axis into which the adjusting screw 3 is screwed. The other ends of the springs 6 from those attached to the fixed plate, 1, are pushed into holes in this bar which henceforth connects the springs to the adjusting screw 3 and so to the string plate 2 and so to one end of the instruments strings.

5; Arm-this is a bent piece of metal threaded at one end to enable it to be screwed into the string plate 2.

6; Counterbalancing springs-these are extension springs attached at one of their ends to the fixed plate 1 and connected to string plate 2 via adjusting bar 4 and adjusting screw 3 at their other ends.

OPERATION When this invention is fitted to a suitable instrument, the strings are attached at one of their ends to the tuning devices, known as machine heads, fitted at one end of the instrument, being the end of the neck not attached to the body of the instrument, and the other ends of the strings are attached to this invention which is mounted on the body of the instrument. As the strings are tuned up, that is they have their tension raised by means of the machine heads, so the string plate 2 tends to rotate about the pivot point, which in this case is the knife edge. The adjusting screw 3 is turned to draw the adjusting bar 4 closer to the string plate 2 and henceforth increase the tension of the counterbalancing springs 6 to counteract the influence of the string tension on the string plate 2. The strings and counterbalancing springs 6 are adjusted until all the strings are at their required tension and the spring plate 2 is perpendicular to the fixed plate 1; a stable balanced state is now deemed to have been achieved. The stabilising factor is the head of the screw 3. As can be seen from the drawings, when the invention is in its stable tuned state the head of the adjusting 3 is flat against the machined recess face in the string plate 2. When the string plate 2 is moved by pressure exerted on the operating arm 5 to cause the string plate 2 to rotate about the pivot point to effect a lowering of pitch of the strings, it can be seen from the pitch lowered state diagram that only the lower edge of the adjusting screw 3 head bears against the string plate 2 which increases the distance of the point of the counterbalancing springs influence from the pivot point henceforth increasing the leverage of the counterbalancing springs. Also the string tension has been reduced and henceforth the strings influence over the string plate 2. This causes a rapid return to the stable tuned state when the pressure being exerted on the arm 5, and therefore on the string plate 2, is relieved. Conversely, when pressure is exerted on the arm 5 to cause the string plate 2 to rotate about the pivot point to effect an increase in tension of the strings and henceforth raise their pitch, it can be seen from the pitch raised state diagram that the upper edge of the adjusting screw 3 is bearing against the string plate 2 and is therefore reducing the distance of the point of the counterbalancing springs 6 influence from the pivot point and henceforth reducing the leverage of the counterbalancing springs 6.

This means that the strings of the instrument, which are increased in tension, bring about a rapid return to the stable tuned state when pressure on the arm 5, and there on the string plate 2, is relieved.

As can be seen from the diagrams of operation the head of the adjusting screw 3 will always try to lie flat against the string plate 2. This is the main stabilising feature of the invention and provides greater stability should a string break or be bent, enabling a player to continue playing in tune. The size of the head of the adjusting screw 3 has a major effect on the stability of the invention, the larger the head the greater the stability, but the device becomes more difficult to operate, so a suitable compromise would seem to be stability when one string breaks or is bent, on the premise that if more than one string breaks it would not be possible to continue playing the instrument for other reasons. Another way of increasing the stability of the device further is to use more or stronger counterbalancing springs. This results in minimal spring extension being required to achieve a stable tuned state and the springs go completely slack during the raising of the strings pitch operation, but the operation of the invention when lowering the pitch of the strings requires more pressure on the arm 5, although a few instrumentalists might prefer this.

Claims (1)

1. CLAIMS What is claimed is; 1; This invention, being a tremolo device which is mounted on a musical instrument having a body and a neck portion, the neck being attached at one end only to the body, and strings, stretched at right angles to the neck and attached to that end of the neck not attached to the body by means of tension adjusting devices commonly known as machine heads. The other ends of the strings are attached to the invention which is mounted onto the body of the instrument. This tremolo device will retain its integrity and remain fully operational should one string break or be bent.

   2; That the geometrical design will ensure that the characteristics described in claiml will be realised.

   3; That the adjusting screw head geometry will ensure that the characteristics described in claim 1 will be realised.

   4; That the pivot is a full width knife edge.

   5 ; That no locking device is needed.