WO1996033485A1

WO1996033485A1 - Tremolo arrangement for stringed instruments

Info

Publication number: WO1996033485A1
Application number: PCT/GB1996/000920
Authority: WO
Inventors: Neil Alexander Clark
Original assignee: Sime, Timothy, John
Priority date: 1995-04-18
Filing date: 1996-04-17
Publication date: 1996-10-24
Also published as: GB9507879D0

Abstract

A tremolo arrangement for stringed instruments comprises a pivoting string bridge (17) which is mounted to a leaf spring (1) which is acted upon during operation so as to twist in torsion about an axis of torsional flexure which is oriented in a common direction with the pivotal axis of the bridge (17). The use of a torsionally twisting leaf spring (1) as support amount for the bridge element (17) (to carry the principal loads of the system) minimises frictional losses and ensures a return to 'true tuning' subsequent to operation. The string bridge (17) of the tremolo arrangement may be utilised as a tailpiece spaced from a conventional primary string supporting bridge, or alternatively comprise a replacement for a conventional primary bridge. As a further alternative, the arrangement may be provided as a combined tailpiece and bridge assembly.

Description

Tremolo Arrangement for Stringed i s-fc-ruiiianfca

This invention relates to a tremolo arrangement for a stringed instrument.

Tremolo arrangements are commonly utilised in stringed instruments (principally guitars) to allow the musician to introduce a "vibrato" effect, raising and lowering the pitch of played notes.

Typically an actuation lever is operatively connected to a string contacting bridge which is mounted to be pivotably movable to alter the tension in, or the effective length of, the strings. Spring biasing is commonly used to restore the bridge to its "normal" position subsequent to operation of the tremolo lever.

Examples of tremolo arrangements utilising spring biasing are disclosed in for example WO-A-93/14490 (which utilises a coil torsion spring) , GB-A-2256077 (which utilises a cantilevered leaf spring) and US-A-500711 (which also utilises a leaf spring arrangement) .

In the arrangements shown in WO-A-93/14490 and US-A- 500711, primary loads imparted by the strings to the bridge element are transferred to a "knife edge" bearing in which frictional effects can result in failure of the tremolo bridge to return to its normal (at rest) position. As a consequence, the instrument would be out of tune. Some tremolo arrangements have a further drawback in that, in using the tremolo arm, strings drag across the bridge or string saddles causing wear and further detuning problems. Furthermore, most knife edge bearing tremolo arrangements and cantilevered leaf spring arrangements experience disadvantages in that the strings are raised and lowered during operation, thereby altering the "action" of the instrument. A further drawback of the systems proposed in WO-A- 93/14490 and US-A-3500741 is that they are relatively complex in nature. In particular, the device disclosed in US-A-3500741 discloses an arrangement in which a tremolo arrangement and a separate (primary) string supporting bridge are required. An improved apparatus has now been devised.

According to a first aspect, the invention provides a tremolo arrangement for a stringed instrument which arrangement comprises a string bridge element and mounting means arranged to mount the bridge element for pivotable movement relative to the instrument, the mounting means comprising a leaf spring element arranged to be acted upon by the bridge element so as to flex in torsion about an axis of torsional flexure which is oriented in a common direction with the pivotal axis of the bridge element.

The use of a torsionally twisting leaf spring element as support mount for the bridge element (to carry the principal loads of the system) minimises frictional losses and ensures a return to "true tuning" subsequent to operation.

It is preferred that the pivotal axis of the bridge element and/or the axis of torsional flexure of the leaf spring element is/are orientated intermediate the forward and rearward limits of the bridge element. Preferably the pivotal axis of the bridge element and the axis of torsional flexure of the leaf spring coincide.

Advantageously, string contacting portions carried by the bridge element are provided substantially directly above the pivot and/or torsional flexure axis. Desirably, the string contacting portions of the bridge element have string contacting surfaces which are curved at a radius of curvature corresponding to the distance of the supported string from the pivot and/or torsional flexure axis.

These features provide that, in pivoting the tremolo bridge element, raising/lowering of the strings relative to their "normal" position is minimised.

It is preferred that the leaf spring element comprises an elongate substantially flat planar spring element, the axis of torsional flexure of the leaf spring element being arranged in its longitudinal direction.

Desirably, the effective stiffness of the leaf spring element about its axis of torsional flexure is adjustable.

At least a portion of the leaf spring element is preferably arranged to be fixed relative to a portion of the instrument so as not to flex (twist) significantly about the axis of torsional flexure, a spaced portion of the leaf spring element being permitted to flex (twist) significantly about the axis of torsional flexure. In this embodiment, the relative proportion of the leaf spring being permitted to flex (twist) compared to the relative proportion inhibited from flexing (twisting) significantly, determines the effective stiffness of the leaf spring element for a given applied twisting force.

It is therefore possible to adjust the degree of torsional stiffness of the leaf spring by adjusting the size of the portions which are fixed relative to the instrument/bridge element.

In a preferred embodiment, portions of the leaf spring element proximate longitudinally opposed ends thereof are arranged to be fixed relative to the instrument such that a portion of the leaf spring element intermediate the opposed ends is permitted to flex (twist) about the axis of torsional flexure.

In an alternative embodiment a portion of the leaf spring element intermediate the opposed ends may be fixed relative to the instrument such that opposed end portions of the leaf spring element are permitted to flex (twist) about the axis of torsional flexure.

In view of the above considerations it is preferred that securing means is provided comprising one or more fixings arranged to secure at least a portion of the leaf spring element relative to the instrument.

Advantageously, the mounting means comprises adjustment means arranged to provide for adjustment of the level of the bridge element.

It is preferred that the mounting means comprises contacting portions arranged primarily to transmit vibrational energy from the bridge element to a body portion of the instrument along a path by passing the leaf spring element.

It is believed that a tremolo arrangement having contracting portions arranged primarily to transmit vibrational energy from the bridge to the body of the instrument along a path by passing biasing spring means is both novel and inventive per se.

Desirably, the contacting portions provide a relatively low friction contact between the pivoting bridge element and a mounting element arranged to be fixed relative to the body of the instrument. Advantagously, the contacting portions are arranged such that negligible (preferably nil) string tension forces are transmitted via the contacting portions.

The string bridge element of the tremolo arrangement may comprise a tailpiece spaced from a conventional primary string supporting bridge, or alternatively comprise a replacement for a conventional primary bridge. As a further alternative, the arrangement may be provided as a combined tailpiece and bridge assembly. In embodiments where the arrangement functions as a tailpiece, the assembly is preferably provided with a tailpiece portion having receiving formations for receiving terminal portions of the strings of the instrument. Such receiving formations are preferably "hammer claw" formations arranged to receive projections or balls defining terminal portions of respective strings of the instrument.

It is preferred that the bridge element is arranged to carry string contacting formations (such as saddles) secured to the bridge (for example by means of screws) . Desirably the string contacting formations are provided as respective fixing elements, each fixing element carrying a pair of contacting formations in spaced side by side relationship, securing means being provided in the intermediate space between each spaced pair of contacting formations for each fixing element. The securing formations may comprise a slot or aperture arranged to receive a mechanical fixing (such as a screw or the like) . It is believed that such fixing elements are novel and inventive per se.

According to a further aspect, the invention provides a tremolo arrangement for a stringed instrument, which arrangement comprises a string bridge element arranged to suspend the strings of the instrument at a playing level, the bridge element being mounted with a resiliently flexible spring element so as to be pivotable about a pivot axis common with the axis of flexure of the spring element, the common axes being oriented intermediate the forward and rearward limits of the string bridge element.

The invention will now be further described in specific embodiments by way of example only, with reference to the accompanying drawings, in which:

Figure 1 is a schematic perspective view of a first embodiment of tremolo arrangement for attachment to a stringed instrument, the arrangement comprising a combined tremolo bridge tailpiece;

Figure 2 is an end view of the apparatus of Figure 1 when mounted on the body of a musical instrument;

Figure 2a is a perspective view of a part of the apparatus of Figures 1 and 2;

Figure 3 is a view of components of the arrangement of Figures 1 and 2;

Figures 4a and 4b are exemplary representations of a suitable leaf spring element;

Figure 5 is a schematic sectional view through part of the arrangement of Figures 1 and 2;

Figures 6a and 6b are sectional views similar to that of Figure 5 showing the leaf spring and bridge element in differing orientations;

Figure 7 is a schematic sectional view of an alternative embodiment of tremolo apparatus according to the invention, the embodiment comprising a tremolo bridge;

Figure 8 is an exploded view showing components of the arrangement of Figure 7;

Figures 9 and 10 are side and plan views respectively of an alternative arrangement of tremolo according to the invention; and

Figures 11 and 12 are perspective and plan views respectively of a preferred embodiment of string contacting element for attachment to a bridge element.

Referring to the drawings, and initially to Figure 1 in particular, there is shown a tremolo assembly comprising a bridge piece 17, the rear corner of which is connected to a tremolo lever arm 25. Bridge piece 17 is mounted on a leaf spring 1 by means of screws 18 which pass through apertures 31 in the leaf spring 1 and are received in threaded bores in the underside of bridge element 17. Apertures 31 for accommodating screws 18 are clearly shown in Figure 3.

Securing pieces 27 having U-shaped notches 28 are provided at either end of leaf spring 1, and are shaped to receive neck portions 29 of threaded mounting pins 3. Mounting pins 3 are receivable in threaded bushes 4 which are sunk into the body of the instrument 30. The depth to which mounting pins 3 are threaded into bushes 4 enables the height of the bridge piece 17 above the body of the instrument 30 to be varied. The mounting system provides an extremely low profile for the tremolo arrangement and enables such an arrangement to be used as a direct replacement for conventional non-tremolo bridges or tailpieces (providing the threads and fixing centres of mounting pins 3 are compatible) .

Bridge 17 is provided with a series of "hammer and claw" tailpiece formations 22, and string saddle locating projections 15 to enable strings to be secured to the bridge and appropriately suspended in use. The "hammer and claw" formations enable strings to be changed more speedily and reduce "settling in" time.

When tremolo arm 25 is raised and lowered bridge piece 17 pivots in unison with the central portion of leaf spring 1 about a longitudinal torsional axis of flexure of spring l. The longitudinal torsional axis of flexure is most clearly shown in Figure 4a and 4b and identified by axis x. In figure 4a, the leaf spring 1 is shownin an unflexed state. In figure 4b, the leaf spring 1 istwisted about its torsional axis of flexure x such that the forward edge of leaf spring 1 in the region of its central portion twists downwardly, the rearward edge twisting correspondingly upwardly. The spaced opposed ends are inhibited from flexing because they are clamped by securing pieces 27. It is important to note that the axis of flexure of the leaf spring 1 and the pivotal axis of the bridge piece 17 are coincident and the string contacting surface of saddle projections 15 are correspondingly curved at the radius of curvature. These features provide that string height during operation of the tremolo arrangement is maintained substantially constant.

It should further be noted that the tailpiece tremolo arrangement is held in an energised condition by the tension of strings 13 such that normally the tremolo arrangement rests with the leaf spring 1 a state of partial flexure as shown in Figure 6b, rather than with the leaf spring unflexed (as shown in Figure 6a) prior to tensioning of strings 13. Upper and lower surfaces of bridge 17 are relatively inclined such that bridge 17 is wedge shaped, such that when the strings are tensioned (and leaf spring 1 is partially twisted as shown in Figure 6b) the upper surface of bridge 17 lies flat with respect to the surface of the instrument.

The area over which screws 18 connect leaf spring 1 to bridge piece 17 determines the effective stifness of the arrangement about the torsional axis of flexure of the leaf spring 1.

Referring now to Figures 7 and 8, there is shown an alternative embodiment of tremolo according to the invention. In the embodiment shown, the central portion of leaf spring 1 is secured by screws 7 to a mount 8 provided on the body of the instrument (alternatively, the central portion could be secured directly to the body of the instrument) . The opposed longitudinal end portions of leaf spring 1 are free to flex (twist) about the torsional axis x; necked portions 33 of leaf spring 1 provide increased flexibility. Mounting pins 5, have ends which are secured to leaf spring l, the other ends of mounting pins 5 being retained relative to bridge 12 by means of a connecting washer 6. Height adjustment for the bridge 12 is provided by means of washers 6 and threaded screws 14 which can permit mounting pins 5 to project variable distances into a receiving cavity 32.

When the tremolo lever arm (not shown) is operated, bridge 12 pivots about the torsional axis of flexure of leaf spring 1, as the ends of leaf spring 1 are forced to twist. Upon release of the tremolo lever arm, the ends of leaf spring 1 spring resiliently back to their original position, restoring bridge 12 to its "normal" position.

Figures 9 and 10 shown an alternative tremolo arrangement which is not intended to also act as a tailpiece. In the embodiment shown, bridge piece 12 can be mounted to a leaf spring element in the manner described in the embodiments of Figures 1 to 6 and Figures 7 and 8. String bearing saddle components 15 are provided in a similar manner, however in this embodiment string locks 11 are provided to clamp the strings relative to the bridge 12 in order to ensure the strings move back and forth with the bridge 12 rather than grating across the bridge. String locks 11 comprise a threaded pin 10 which threadingly engages with the bridge 12, and a clamp piece 9 to act on the strings to clamp the strings in pairs.

Referring to Figures 11 and 12, there is shown a novel string support (or saddle) 15. Saddle 15 carries a pair of string contacting elements 15a, 15b, a fixing slot 41 being provided along an axis dividing the pair. The advantage of this is that a single adjusting screw 16 can be used to fix the saddle 15 to the bridge 17,12. The screw is particularly accessible for adjustment because it lies intermediate the two strings carried by respective string contacting elements 15a, 15b.

A further feature of the invention is the provision of a mechanical bypass to transmit vibration from the bridge to the body of the instrument along a path which does not primarily include the leaf spring 1. Tremolo arrangements utilising a "knife edge" bearing do not require such a bypass arrangement because good mechanical connection is maintained between the bridge and the securing connections via the "knife edge" bearing. Such bearings however are also required to bear frictional, string and spring tension forces.

For the embodiment of the invention described in Figures l and 2, the mechanical vibrational bypass is provided by means of an insert 19 which is received in a recess 19a in the side of bridge 17. Insert 19 provides a sliding connection between bridge 17 and securing piece 27 to transmit vibration to the body 30 via pins 3 along a path other than via spring 1 alone. The vibration affecting leaf spring 1 is thereby reduced, minimising adverse effects upon tone and sustain.

For the embodiment of the invention described in Figures 7 and 8 rounded head 20 of mounting pin 5 is in contact with the body of the device via a hard mount 21. As the tremolo arrangement pivots during operation, vibration is transmitted from bridge 12, via washer 6, pin 5 and mounts 21 and 8 to the body of the instrument.

Claims

claims :

1. A tremolo arrangement for a stringed instrument which arrangement comprises a string bridge element and mounting means arranged to mount the bridge element for pivotable movement relative to the instrument, the mounting means comprising a leaf spring element arranged to be acted upon by the bridge element so as to flex in torsion about an axis of torsional flexure which is oriented in a common direction with the pivotal axis of the bridge element.

2. A tremolo arrangement according to claim 1, wherein the pivotal axis of the bridge element and/or the axis of torsional flexure of the leaf spring element is/are orientated intermediate the forward and rearward limits of the bridge element.

3. A tremolo arrangement according to claim 1 or claim 2, wherein string contacting saddle portions carried by the bridge element are provided substantially directly above the pivot and/or torsional flexure axis.

4. A tremolo arrangement according to any preceding claim, wherein the leaf spring element comprises an elongate substantially flat planar spring element.

5. A tremolo arrangement according to claim 4, wherein the axis of torsional flexure of the leaf spring element is arranged in its longitudinal direction.

6. A tremolo arrangement according to any preceding claim, wherein the effective degree of torsional flexure of the leaf spring element about its axis of torsional flexure is adjustable. 7. A tremolo arrangement according to any preceding claim, wherein at least a portion of the leaf spring element is arranged to be fixed relative to a portion of the instrument so as not to flex significantly about the axis of torsional flexure, a spaced portion of the leaf spring element being permitted to flex significantly about the axis of torsional flexure.

7. A tremolo arrangement according to claim 6, wherein portions of the leaf spring element proximate longitudinally opposed ends thereof are arranged to be fixed relative to the instrument such that a portion of the leaf spring element intermediate the opposed ends is permitted to flex about the axis of torsional flexure.

8. A tremolo arrangement according to claim 6, wherein a portion of the leaf spring element intermediate the opposed ends is arranged to be fixed relative to the instrument such that opposed end portions of the leaf spring element are permitted to flex about the axis of torsional flexure.

9. A tremolo arrangement according to any preceding claim, wherein the bridge element is secured to the leaf spring element.

10. A tremolo arrangement according to any preceding claim wherein the mounting means comprises one or more mechanical fixings arranged to secure the leaf spring element relative to the instrument.

11. A tremolo arrangement according to any preceding claim, wherein the mounting means comprises adjustment means arranged to provide for adjustment of the level of the bridge element relative to the instrument.

12. A tremolo arrangement according to any preceding claim, wherein the mounting means comprises contacting portions arranged to transmit vibrational energy from the bridge element to a body portion of the instrument along a path by passing the leaf spring element.

13. A tremolo arrangement for a stringed instrument comprising according to any preceding claim provided further with a tailpiece portion having receiving means for receiving terminal portions of the strings of the instrument.

14. A tremolo arrangement according to claim 13 , wherein the tailpiece portion is provided with "hammer claw" formations for receiving terminal portions of respective strings of the instrument.

15. A tremolo arrangement for a stringed instrument, which arrangement comprises a string bridge element arranged to suspend the strings of the instrument at a playing level, the bridge element being mounted with a resiliently flexible spring element so as to be pivotable about a pivot axis common with the axis of flexure of the spring element, the common axes being oriented intermediate the forward and rearward limits of the string bridge element.

16. A tremelo arrangement according to claim 15, wherein the arange ent is provided with mounting means for mounting to the instrument, the mounting means comprising contacting portions arranged to transmit vibrational energy from the bridge element to a body portion of the instrument along a path by passing the leaf spring element.

17. A tremolo arrangement according to claim 15 or 16, wherein string contacting saddle portions of the string bridge element are provided substantially directly above the pivot axis.

18. A tremolo arangement according to any of claims 15 to 17, wherein the spring element comprises a leaf spring element advantagously arranged to flex (twist) in torsion.

19. A tremolo arrangement for a stringed instrument according to any of claims 15 to 18, provided further with a tailpiece portion having receiving means for receiving terminal portions of the strings of the instrument.

20. A tremolo arrangement substantially as herein described, with reference to the accompanying drawings.