A non-displaceable, self-righting shim for use in any application where critical alignment is required of adjacent vertical elements. The shim presents an elongated central opening including a large upper portion and a small lower portion, and a slot having an exit end communicating with the central opening and an entrance end at the perimeter edge of the shim. The weight distribution of the shim relative to the large upper portion is such that the shim will hang in a normal upright position with the small lower portion and the slot below the large upper portion. The arrangement assures positive placement of the shim once installed; avoids loosening and fall-off of the shim which may be caused by thermal expansion and contraction of the shimmed element and/or by vibrations associated with the adjacent vertical elements; and eliminates the need for holding the shim in position while securing the fastener.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates generally to shim elements, and more particularly to 
shims of a non-displaceable, self-righting type. 
2. Description of the Prior Art 
Tolerances in the construction industry are such that the alignment of 
erected materials is never perfect. For example, the girts and subgirts of 
the structural framework of a building are intended to have outer faces 
reside in a vertically oriented working plane. Most often, the outer face 
of one or more of the girts or subgirts is inset from the working plane. 
When a panel member is erected on the framework, the fasteners are 
sufficiently tightened to place the panel member snug against the girt or 
subgirts. In the region of the out-of-plane girts or subgirts, the panel 
may bow inwardly creating an unsightly depression. Where the panel members 
have complementary mating elements along the joint edges, the mating 
element of the next-to-be-erected panel member cannot conform to the bowed 
configuration of the previously installed panel member, and cannot easily 
be installed. 
Adjustments are required to overcome such out-of-plane deviations. The most 
common method of adjustment is to use shims or spacers interposed between 
the panel member and the out-of-plane girt or subgirt. Several types of 
shims or spacers have been used in the past, including rectangular pieces 
of material, a standard round washer with a central aperture, and a 
horseshoe-shaped shim. 
While a shim formed of a rectangular piece of material is easily found 
around the jobsite, positive placement of such shims is not possible. Such 
shims may work loose during thermal expansion and contraction of the 
panels and fall off. The once-secure panel portion is now free to vibrate 
under varying wind conditions. 
Standard round washers with a central aperture have been used and are 
positively placed once installed. However it is extremely difficult and 
very time-consuming to hold one or more of the standard round washers in 
position while threading the fastener through the registered central 
apertures. 
U-shaped washers have been used and are most easily installed. The U-shaped 
washer is dropped over the fastener and thereafter the fastener is 
tightened. The U-shaped washer can work loose during thermal expansion and 
contraction of the panel and if rotated sufficiently about the fastener, 
may fall off. 
SUMMARY OF THE INVENTION 
The principal object of this invention is to provide a novel shim which 
overcomes all of the above-described problems. 
Another object of this invention is to provide a shim which is 
non-displaceable and which is self-righting. 
Still another object of this invention is to provide a shim having a unique 
entrance slot and central aperture arrangement which facilitates 
installation and which assures positive placement once installed. 
A further object of this invention is to provide a shim which does not have 
to be held in position while the fastener is secured. 
The present invention provides a non-displaceable, self-righting shim 
comprising a plate of substantially uniform thickness, having a perimeter 
edge. The plate is provided with an elongated central opening which 
includes a large upper portion and a small lower portion; and with a slot 
having an exit end communicating with the central opening and an entrance 
end at the perimeter edge. The slot is inclined such that the entrance end 
resides below and to one side of the exit end and of the central opening. 
The plate has a center of gravity within the central opening but below the 
geometric center of the large upper portion. The overall arrangement is 
such that when the shim is dropped over a fastener shank, the shim will 
move under the influence of its weight and come to rest with the fastener 
shank engaging the peripheral edge of the large upper portion and with the 
small lower portion and the slot below the level of the fastener shank. 
In the preferred arrangement, the large upper portion and the small lower 
portion comprise segments of circles. An edge connects those corresponding 
sides of the large upper portion and of the small lower portion which are 
opposite to the exit end of the slot. In addition, the large upper portion 
includes a node adjacent to the exit end of the slot which projects into 
the central opening. The node serves to bias the shim in a direction which 
maintains engagement of the fastener shank with the periphery of the 
central opening. 
The present shim is useful in a wall structure of the type comprising 
vertically spaced-apart horizontal frame members having outboard faces 
defining a working plane, and at least first and second panel members 
spanning across the frame members and having inner faces intended to be 
supported at the working plane. The panel members have a joint 
therebetween including connecting means connecting the longitudinal edge 
of the second panel member to the longitudinal edge of the first panel 
member. Fastening means is provided which secures the longitudinal edge of 
the first panel member to the frame members. In the event the inner face 
of one or more frame members is inset from the working plane, one or more 
of the present shims is interposed between the first panel member and the 
inset frame member to support the first panel member with the inner face 
thereof substantially at the working plane. The width of the shim or shims 
is such that the second panel also is supported with the inner face 
thereof substantially at the working plane.

DESCRIPTION OF THE PREFERRED EMBODIMENT(S) 
FIG. 1 illustrates a wall structure 20 including plural panels 21 (only one 
visible) erected on a steel framework 22 of a building. The framework 22 
includes vertical columns (not illustrated), horizontal beams 24 and 
plural girts 26, 28, 30 and 32, each presenting an outboard face 34. The 
outboard faces 34 of the frame members 28 and 32 define a working plane 
illustrated by the dash-dot line 36. For the purpose of illustration, the 
outboard faces 34 of the frame members 26 and 30 are shown inset from the 
working plane 36, that is spaced-apart from the inner face 38 of the panel 
members 21. As is the normal practice, one or more shims must be installed 
between the panel members 21 and the frame members 26, 30 to provide a 
firm support for the panel members 21 and to preclude undesirable 
deformation of the panel members 21 when the fasteners are tightened. 
FIG. 2 illustrates a shim 40 of this invention, formed from any suitable 
material having substantially uniform thickness. The shim 40 has a 
perimeter edge including a top edge 42, a bottom edge 44, and opposite 
side edges 46, 48. An elongated central opening 50 is provided in the shim 
40, including a large upper portion 52 and a small lower portion 54, the 
portions 52 and 54 comprising segments of circles connected by a straight 
edge 56 which is tangent to those sides of the portions 52, 54 adjacent to 
the side edge 48 of the shim 40. The large upper portion 52 has a 
geometric center at 58 and extends from the straight edge 56 in a 
clockwise direction for about 180 angular degrees. The large upper portion 
52 terminates in an arc segment 60 having a radius which is smaller than 
that of the upper portion 52. The shim 40 is provided with a slot 62 
having an exit end 64 communicating with the central opening intermediate 
of the upper and lower portions 52, 54 and opposite thereto an entrance 
end 66 at the perimeter edge of the shim 40. The slot 62 is inclined at 
about 45 angular degrees with respect to the vertical centerline 67. 
A fastener shank 68 is shown in dotted outline in FIG. 2, engaged with the 
peripheral edge of the upper portion 52. The central opening 50 and the 
slot 62 are located in the shim 40 such that the shim 40 presents a center 
of gravity 70 which is below the geometric center 58 of the upper portion 
52. When installed on the fastener shank 68, the shim 40 will hang in a 
normal position illustrated in FIG. 2. 
The arc segment 60 cooperates with the contiguous edge of the slot 62 to 
define a node 72 which projects into the central opening 50. Should the 
shim 40 be rotated in a counterclockwise direction as seen in FIG. 2, so 
that the fastener shank 68 engages the arc segment 60, the node 72 will 
bias the shim 40 in a clockwise direction so as to maintain the peripheral 
edge of the upper portion 50 engaged with the fastener shank 68. 
That corner of the shim 40 opposite the entrance end 66 of the slot 62, is 
cut off to provide a flat transverse edge 74 which is adapted to receive 
the blows of a shim-installing-tool, such as a hammer without deforming 
the perimeter edge of the shim 40. 
The slot 62 presents outwardly flared edges 75 at the entrance end 66 
thereby enlarging the entrance end 66 and facilitating introduction of the 
fastener shank 68 into the slot 62. 
The shim 40 may be made in a variety of thicknesses and from any suitable 
material, such as aluminum, metal coated steel, and plastic materials--the 
material of construction being governed by the structure on which the shim 
40 is used. The material of construction for the shim 40 also can be 
selected to eliminate the corrosive action between dissimilar materials. 
FIGS. 3 and 4 illustrate shims 40' and 40", respectively, presenting 
elongated openings 50' and 50" of alternative configuration. In FIG. 3, 
the elongated opening 50' has upper and lower portions 52', 54' each 
comprising a segment of an ellipse. In FIG. 4, the elongated opening 50" 
includes upper and lower portions 52", 54" each comprising a segment of a 
polygon. 
FIGS. 2 to 4 illustrate shims 40, 40', 40" having a polygonal peripheral 
shape, specifically a rectangular shape. The shims 40, 40', 40" may have 
any other desired peripheral shape so long as the geometric center 58 of 
the upper portion 52 is well above the geometric center of the shim 40 and 
so long as a major portion of the elongated opening 50 and the slot 62 are 
below the geometric center 58 of the upper portion 52. Thus configured, 
the shim 40 will have a natural tendency to rotate into the upright 
position illustrated in FIGS. 2 through 4. 
FIGS. 5 and 6 illustrate the installation of the shim 40 on the fastener 
shank 68 and rotation of the shim 40 into the normal upright position. In 
FIG. 5, the slot 62 receives the fastener shank 68. The shim 40 will slide 
in the direction of the arrow 76 until, as shown in FIG. 6, the fastener 
shank 68 engages the peripheral edge of the central opening 50, e.g. the 
edge 56. Under the influence of its own weight, the shim 40 will slide 
along the fastener shank 68 in the direction of the arrow 78 and 
thereafter rotate about the fastener shank 68 and in the direction of the 
arrow 80 until the shim 40 comes to rest in its normal upright position, 
as shown in dotted outline in FIG. 6. 
By way of example, FIGS. 7 and 8 illustrate the use of one or more of the 
shim members 40 at a shiplap joint 82 (FIG. 8) formed between the first 
and second panel members 21A, 21B. In FIGS. 7 and 8, the panel members 
21A, 21B cross over the frame member 30 which, as explained above, has its 
outboard face 34 inset from the working plane 36 (FIG. 8). The panel 
members 21A, 21B present connecting means, such as a tongue 84 and a 
complimentary groove 86 along each of the opposite longitudinal sides 
thereof, which connects the panel member to the now-secured panel member 
21A, 21B as shown in FIG. 8. Each of the panel members 21A, 21B presents a 
lapped edge portion 88 and an overlapping edge portion 90 along the 
opposite longitudinal edges thereof which form the shiplap joint 82. 
Fastening means, such as a clip 92 and a fastener 94, penetrate the first 
panel member 21A at the lapped edge portion 88 and secures the panel 
member 21A to the frame member 30. 
Prior to tightening the fastener 94 (FIG. 7), one or more of the shims 40 
are dropped over the shank 68 of the fastener 94 in the region between the 
inner face 38A of the panel member 21A and the outboard face 34 of the 
frame member 30. Once the inner face 38A of the panel member 21A is 
supported by the shims 40 substantially at the working plane 36 (FIG. 8), 
the fastener 94 is tightened thereby firmly securing the panel member 21A 
to the frame member 30. Thereafter, the panel member 21B is installed as 
shown in FIG. 8 and thereafter the introduction of one or more shims is 
repeated at the opposite edge of the panel member 21B. 
It will be observed in FIG. 8 that the shims 40 are sufficiently wide so as 
to span across the shiplap joint 82. Thus the shims 40 also engage the 
inner face 38B of the panel member 21B and support the same substantially 
at the working plane 36.