String tension adjusting mechanism for a steel guitar

A string tension adjusting mechanism for a steel guitar. The adjusting mechanism consists of three basic parts, a bridge member, over which a guitar string is mounted and to which tension is applied to a desired pitch. A raising lever member, actuated by a pull rod, turns the pivotably-mounted bridge member clockwise to increase the tension and incease the pitch. A lowering lever member, again actuated by a pull rod, causes the bridge member to pivot in a counterclockwise direction, thus relieving the tension on the string and lowering the pitch. One of the lever members is attached to the bridge member, while both of the lever members are pivoted together. One of the lever members contains a large hole and a spacing device is mounted therein, at the point of pivot, to maintain a free space between the two lever members and between the lever member and the bridge. This allows for free and easy raising or lowering of the pitch of a particular string while the guitar is being played and minimizes drag and friction. Maintaining a free space between the lever members and between the lever members and the bridge member produces a pure tone quality. The tone quality is further enhanced by the provision of a large V-shaped notch in the leading edge of the lowering lever.

FIELD OF THE INVENTION 
The invention relates to an improved pitch changing means in the form of a 
string tension adjusting mechanism for a steel guitar. The string tension 
adjusting mechanism is actuated by a pedal attached to a lever for raising 
or lowering the pitch from the normal or tuned pitch. 
DESCRIPTION OF THE PRIOR ART 
Applicant is aware of the following prior art: 
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Pat. No. INVENTOR DATE 
______________________________________ 
4,157,050 Lashley 1979 
4,175,467 Lashley 1979 
4,342,249 McCormick, et al 
1982 
3,014,395 Blair 1961 
3,352,188 Fender 1967 
4,080,864 Jackson 1978 
2,973,682 Fender 1961 
UK Patent Application 
2,035,651A McCann 1980 
______________________________________ 
Pedal steel guitars are commonly tuned by adjusting the tension on the 
strings without the foot pedals being depressed. After the strings have 
been tuned to a desired pitch in the open condition (without depression of 
the pedals), the pedals can be actuated to produce a certain note for the 
responsive string, which is different from that obtained in the open 
condition. The term "pedal," as used herein, refers to knee, hand, foot or 
other lever-operated pedals for obtaining tone variation in either a 
higher or lower tone from the pitch of the tuned, open condition of the 
string. 
SUMMARY OF THE INVENTION 
The invention consists of a string-mounting apparatus and a string 
tension-adjusting mechanism for a pedal guitar, commonly known as a steel 
guitar. The string is tuned in the open condition by adjusting the tuning 
screw with the locking mechanism disengaged. When the string has been 
properly tuned in the open condition, the locking mechanism is engaged. 
The string is then tightly secured to the neck nut, to prevent it from 
loosening or tightening during stress: the opposite end of the string 
having been attached to the attachment pin, so that pivoting of the bridge 
member on its axle in one direction increases the tension on the string, 
thus raising the pitch. Pivoting of the bridge member in the opposite 
direction decreases the tension on this string and thus lowers the tone. A 
spacer member is mounted in a large hole in one of the levers. 
Additionally, the spacer member maintains a free space between the levers 
and between both levers and the bridge member. Only one lever is directly 
attached to the bridge member. Only one lever is attached to a biasing 
spring. The two lever members, however, are pivoted together at the top so 
one can move independently of the other. Additionally, a large, V-shaped 
notch is placed in the body of one of the lever members and this enhances 
the pure tonal qualities of the vibrational characteristics of the string. 
The spacer member also eliminates drag and allows for free and easy 
actuation of the pedals, movement of the raising and lowering levers and 
pivoting rotation of the bridge on its axle in a counterclockwise or 
clockwise direction, without friction or drag.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Turning now to the drawings, FIG. 1 demonstrates the string tension 
adjusting mechanism of the present invention for musical instruments, such 
as a pedal guitar. Such guitars have one or two necks, and each neck will 
contain up to ten strings. Each string involves a separate string tension 
adjusting mechanism so that the total number of such mechanisms would 
equal twenty on a double-neck guitar. For simplicity of illustration, 
however, only a single string is illustrated in operative relationship 
with the appropriate neck portion and the appropriate part of the 
string-adjusting mechanism. 
Referring to FIG. 1, the neck nut means 10 has a base member 10-A, having a 
turning screw 11 with a head 12 and threads 13, which cooperatively react 
with worm gear 14 and rotate around its axle post 15. The terminal end of 
the guitar string 16 is wrapped around axle post 15. The tuning screw 11 
and worm gear 14 comprises the string tuning adjusting means 17, which can 
be used to tighten or loosen string 16 when hold down member 18 is 
disengaged from spring 16. As shown in FIG. 1, hold down member 18 
consists of a set screw which may be replaced with a thumb screw or other 
means to function as a lock down string 16, once it is properly tuned to 
the open condition by adjusting means 17. Connected to the opposite end of 
the string 16 is tone or string tension adjusting means 119, which is 
shown in the assembled condition in FIG. 1. The string securing bridge 120 
can rotate clockwise or counterclockwise around axle 121 to raise or lower 
the tone of string 16. 
For purposes of illustration, the string tension adjusting mechanisms are 
shown in the reversed position in FIGS. 4, 5, 6, 7, 8 and 9, so that the 
clockwise or counterclockwise description has no significance except as 
viewed from the drawings. 
When viewing the apparatus and string adjusting mechanism, as is 
illustrated in FIGS. 1, 2 and 3, on Page 1, the string securing bridge 
member 120 is shown to be pivotably mounted on string securing bridge axle 
121, so that the bridge member 120 can rotate clockwise or 
counterclockwise around axle 121 to raise or lower the tone of string 116. 
The depression of the pedal (not shown) which is connected to raising rod 
122 urges string securing bridge member 120 in a clockwise direction, 
whereas depression of the pedal (not shown) connected to lowering rod 123, 
causes string securing bridge member 120 to rotate in a counterclockwise 
direction, thus lowering the tone of string 116. Both rods 122 and 123 are 
of the pull variety so that the raising and lowering levers 130 and 131 
are actuated by pulling and not pushing. Raising rod 122 has an adjusting 
cap 124 and lowering rod 123 has an adjusting cap 125, each of which are 
threaded and which are used by the musician to tune string 116 further 
after it has been tuned in its "free" or open position. Additionally, 
spacer means 126 are also shown for rods 122 and 123. The string tension 
adjustment member 119 comprises a bridge member 120, mounted on axle 121. 
The raising rod 122, attached to pedals (not shown), pulls the raising 
lever member 131, in attachment with bracket 141. The lowering rod 123, 
similarly pulls upon depression of the pedal (not shown) and is attached 
to bracket 142 for the lowering lever member 130. The lowering lever 
member 130 and the raising lever member 131 pivot point 134. 
Rivet 135, has a head 136 and a washer 137. It will be noted that the 
spacer 133 fits over the shaft of rivet 132 and is located in assembled 
condition in the large elliptical hole 143 in the lowering member 130. The 
shaft of the rivet 132 extends through bridge member 120, so that the 
raising member 131 is pivotably connected to the bridge member 120. 
Lowering member 130, however, is not physically attached to the bridge 
member, but engages when the spacer member 133 reaches the terminal ends 
of the elliptical hole 143 during the excursion of the lowering member 
bracket 131. 
The raising lever member 131 and the lowering lever member 130 are pivoted 
together at point 134 via rivet 135, having a rivet head 136. The washer 
137 fits around the shaft of the rivet 135, allowing for easy movement of 
the raising member 131, relative to lowering member 130. 
As will be noted, the spacer 133, fitting in the elliptical hole 143 of the 
lowering member 130, has a greater thickness than the thickness of the 
lowering member 130. As is best shown in FIG. 2, the spacer member 133 
defines a free space between the depending legs of the raising lever 
member 131 and the depending leg of the lowering lever member 130 and 
additionally maintains free space between the upper portion of the 
lowering member 130 and the lower portion of the bridge member 120. 
Additionally, the flattened-out portion of the rivet 135 on the outside 
surface of lowering lever member 130 fits into a groove 138 so as not to 
engage the bridge member 120. The attachment pin 127 is for the terminal 
portion of the string 116 and increases the tension thereon and thus the 
tone when the bridge member 120 pivots in one direction around bridge axle 
121. Additionally, when the bridge member 120 pivots in the opposite 
direction around axle 121, the pin 127 moves in the opposite direction, 
thus decreasing the tension on the string 116 and lowering the tone. 
As previously noted, FIGS. 4, 5 and 6 illustrate the string tension 
adjusting mechanism described by Lashley in U.S. Pat. No. 4,175,467. Where 
possible, the numbers utilized by Lashley are utilized in these drawings 
so as to describe the relationship of the parts in both the raising and 
lowering of the pitch. The drawings have been made from the reverse side, 
since it was felt that the movement of the parts were better seen from 
that perspective. Accordingly, what Lashley refers to as clockwise in his 
description, will appear to be counterclockwise in this description and 
additionally, the counterclockwise designation of Lashley will appear to 
be clockwise, when viewed from the other side of the mechanism. 
OPERATION 
As has previously been mentioned, the string tension adjusting mechanism of 
Lashley is illustrated in FIGS. 4, 5 and 6, while the string tension 
adjusting mechanism of the present invention is illustrated in FIGS. 7, 8 
and 9. FIGS. 4 and 7 illustrate the neutral position. FIGS. 5 and 8 
illustrate the position for raising the pitch and FIGS. 6 and 9 illustrate 
the method of lowering the pitch. The method of raising the pitch appears 
to be fairly straightforward. As is shown in both FIGS. 5 and 8, as rods 
22 and 122, respectively, pull the raising members 31 and 131 to the 
right, the bridge member 21 and 121 pivot counterclockwise, thus lowering 
the attachment pin 27 and 127, as is shown, to raise the tension on the 
string 16 and 116 and thus raise the pitch. However, there is a 
substantial difference in the method described by Lashley and the 
apparatus of the present invention in lowering the pitch and in moving the 
bridge member 20 and 120 in a clockwise direction, to release the tension 
on string 16 or 116 and thus lower the pitch. 
Lashley describes the operation of the mechanism in Column 3, lines 22-35. 
He states that when rod 23 is pulled, the lowering member 30 pivots 
clockwise (counterclockwise in the drawing), causing the raising member 31 
to rotate in a clockwise direction (counterclockwise in the drawing), 
causing securing bridge member 20 to pivot counterclockwise around bridge 
member axle 21, lowering the tension on the string 16. As is shown in FIG. 
6, the lowering lever member 30 (shown in phantom lines) moves from the 
neutral position, bringing the bracket member 42 flush against the back 
wall 46 of notch 45 into engagement. Thereafter, further movement of 
lowering lever member 30 pulls the member 31 to rotate in a clockwise 
direction pivotably around axle 21, thus causing the bridge member 20 to 
pivot clockwise, thus lowering the tension on string 16. As previously 
mentioned, FIG. 6 is viewed from the opposite side, so that the directions 
are opposite, i.e. counterclockwise is clockwise, and as is shown, pin 27 
does move to lower the tension on the string 16, thus lowering the pitch. 
The point is that Lashley does involve engagement of the tone raising 
member 31 to lower the pitch and the tension on the string 16. In the 
present invention, on the other hand, movement of the lowering lever 
member 130 by actuating of the lowering rod 123, causes the bridge member 
120 to rotate in a clockwise direction, thus lowering the tension on the 
string 16 and thus lowering the tone. The movement of the attachment pin 
127 of the bridge 120 can be seen in comparison to the position in the 
neutral position in FIGS. 7 and 8. The reason this operates is because 
actuation of the pedal causes the lowering rod 123 to pull the lowering 
lever member 130 to the right (as illustrated) due to the release of 
tension on string 50 caused by the actuation of the foot pedal. In other 
words, the movement of the foot pedal and its associated lowering rod 123 
by the muscles of the player's legs counteracts the biasing pressure of 
the spring 150 and allows the tension on string 116 to pull the attachment 
pin upwardly and pivot the bridge member 120 in a clockwise direction, 
thus lowering the tension on the string and lowering the tone. It is 
significant in this instance, that there is no movement whatsoever of the 
raising lever member 131, which remains rested against stop member 129. 
According to this invention, therefore, each of the tone-changing lever 
members 130 and 131 act independently of the other and one does not move 
while the other is being actuated. Additionally, because of the spacer 
member 133, a free space is maintained between the lever members and 
between the lever member assembly and the bridge member 120. Therefore, 
friction and drag are minimized and a pure tonal quality is achieved, 
since the various members do not act to dampen the tone, one against the 
other. 
Because of the preferred arrangement, in which the raising lever member 131 
is located on the outside of the lowering lever member 130 and the rivet 
heads 136 and 132-A, respectively, extend to the outside edge of the 
raising lever member 131, it is is necessary to provide grooves 139 and 
140, on the side surface of the depending leg of bridge member 121. Thus 
the rivet heads 136 and 132-A fit into these grooves and there is no 
contact, between one string tension adjusting mechanism assembly and an 
adjacent string tension adjusting mechanism. 
Many modifications will occur to those skilled in the art from the 
description hereinabove given and such is meant to be illustrative and 
nonlimiting, except so as to be commensurate in scope with the appended 
claims.