Target including sliding scale

The target includes an L-shaped member in which the short leg defines a fixed jaw. A second jaw is slidably mounted on the long arm of the member, which jaw is associated with latching means so that the two jaws can engage against the opposite side walls of a tire and be retained thereby. A second arm is spaced from and attached to the first arm and slidably carries a scale.

BACKGROUND OF THE INVENTION 
In observing and adjusting the track of a wheeled vehicle such as an 
automobile or truck, a source of a beam of light or light projector is 
mounted on one wheel and a scale on the other wheel on the same side of 
the vehicle. "Track" refers to the ability of the rear wheels to follow 
the path set by the front wheels. The scale bears graduations which are 
impinged by the projected light, signifying to the mechanic the extent to 
which the wheels are in track. Adjustments to the steering or suspension 
linkage can be made to adjust the track to be within acceptable limits for 
the vehicle. 
Prior art scales are attached to structure that is mountable on the hub of 
the wheel or on the tread surface of the tire carried by the wheel. There 
are disadvantages of both. When the scale is attached to the hub, 
measurements from a reference point of the vehicle, such as the body 
frame, drive shaft or side wall, to the scale cannot readily be made. Such 
measurements are also difficult to make with respect to a scale mounted on 
the tread surface. Certain such prior art devices contact the outer side 
wall of the tire at its bottom, so that the scale is not oriented 
horizontally. 
SUMMARY OF THE INVENTION 
It is therefore an important object of the present invention to provide a 
target for use in equipment for aligning a vehicular wheel, which is so 
located with respect to the wheel that its distance from a measuring point 
on the vehicle, such as the body, frame, drive shaft or side wall of the 
tire itself, can be readily determined. 
Another object is to provide such a target which can be slid toward and 
away from the vehicle and then latched at a selected position. 
Another object is to provide such a target which includes structure that 
grips the tire side walls. 
Another object is to provide such a target having a scale which can be 
oriented horizontally in use. 
Another object is to provide such a target in which the scale is outside of 
the cylinder defined by the tread surface of the tire. 
In summary, there is provided a target for use in equipment for aligning a 
vehicular wheel which carries a tire thereon having a tread surface and a 
pair of side walls, the target comprising an elongated body, first and 
second jaws depending from the body for respectively engaging the side 
walls of the tire, at least one of the jaws being movable toward and away 
from the other of the jaws, first means for latching the jaws at a 
selected spacing therebetween so as to be mounted on the tire, scale means 
slidably carried by the body, and second means for latching the scale at a 
selected position on the body. 
The invention consists of certain novel features and a combination of parts 
hereinafter fully described, illustrated in the accompanying drawings, and 
particularly pointed out in the appended claims, it being understood that 
various changes in the details may be made without departing from the 
spirit, or sacrificing any of the advantages of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
In FIG. 1, the front, left side of an automobile 10 is depicted in phantom, 
the automobile having a wheel 11 and a hub 12 attached to a shaft (not 
shown). Carried by the wheel 11 is a tire 13 having a cylindrical tread 
surface 14 and a pair of side walls 15 (only one is shown). 
To measure the so-called "track" of an automobile, a target 20 
incorporating the features of the present invention is mounted on the 
front tire 13. Attached to the rear wheel or tire on the same side of the 
vehicle is a light projector (not shown) which generates a beam of light 
aimed at the target 20. By noting the point of impingement of the light 
beam on a scale associated with the target 20, as will be explained, and 
by making a number of other measurements, a mechanic can determine the 
extent to which the front and rear wheels track. Certain adjustments are 
made in the steering linkage(s) or the suspension system to adjust the 
track, if needed. Another target identical to the target 20, but a mirror 
image thereof, and an associated light generator are mounted on the other 
side of the vehicle. Certain procedures require switching the targets and 
light projectors both front to back and side to side. 
Referring to FIGS. 2 and 3, the target 20 includes an elongated body 21 
defined by a pair of laterally spaced apart and parallel arms 22 and 23. 
The arm 23 has three detent openings 23a at predetermined locations on the 
rear surface thereof. A pair of spacers 24 hold the arms 22 and 23 in 
spaced, parallel relationship. Screws 25 pass through the arms 22 and 23 
and are threaded into the spacers 24. In the embodiment shown, the arm 23 
is formed of a straight length of square tubing. The arm 22 is defined by 
the longer leg of an L-shaped member, which in the embodiment depicted, is 
a square tube. A handle 26 is attached to the left-hand end of the arm 23. 
The shorter leg of the L-shaped member defines a fixed jaw 27. Plastic end 
caps 28 are applied to the ends of the arm 23 and to the free end of the 
jaw 27. 
The target 20 includes a movable jaw 30 which is generally U-shaped in 
transverse cross section, having parallel sides 31 and a connecting wall 
32. A pad 33 is attached to the connecting wall 32 which is of 
sandpaper-like finish to facilitate gripping the tire. The connecting wall 
32 has a square opening therein of a size slightly larger than the cross 
section of the arm 22 so that the jaw 30 is freely movable thereon. The 
sides 31 taper toward the connecting wall 32 at the outer ends thereof. 
The target 20 further comprises a latching means 34, which includes a 
bearing plate 35 from which extend two integral side flanges 36 and one 
end flange 37. The side flanges 36 are welded to the interior of the sides 
31 adjacent to the inner ends thereof. The latching means 34 further 
includes a U-shaped bearing member 40 having end flanges 42 which are 
welded to a plate 43. The connecting wall 44 of the bearing member and the 
plate 43 have square openings respectively therein slightly larger than 
the cross section of the arm 22 so as to be slidably movable thereon. The 
latching means 34 further include a compression spring 45 having one end 
looped into a hole in the end flange 37 and the other end attached to the 
member 40. Referring also to FIG. 4, the latching means 34 further 
includes a release lever 47. A lip 48 is formed on the lever 47 at an 
acute angle therewith. The lever 47 has a generally square opening therein 
which is slightly larger than the cross section of the arm 22 so as to be 
freely movable thereon. The opening has two arcuate sides oriented as 
shown. The lever 47 is located between the wall 44 and the plate 43, with 
the lip 48 of the lever 47 enveloping one edge of the plate 43. 
Referring to FIG. 5, to mount the target 20 on a tire, the distal end of 
the lever 47 is drawn against the plate 43 to place the latching means 34 
in its release position, as shown in phantom in FIG. 5. The lever 47 is 
held against the plate 43 and the two are drawn toward the handle 26. Such 
action draws the spring 45 and thus the movable jaw 30 away from the jaw 
27, until the space between them exceeds the width of the tire. Referring 
to FIGS. 1-3, the mechanic can grip the target 20 by holding the handle 26 
in one hand. Then the target is positioned such that the jaw 27 is located 
adjacent to but spaced from the inner side wall of the tire and the jaw 30 
is adjacent to but spaced from the outer side wall of the tire. While 
holding the handle 26 in one hand, the other hand is used to push against 
the plate 43, causing the jaw 30 to move toward the jaw 27. Further 
movement of the plate 43, after the jaws 27 and 30 respectively engage the 
side walls of the tire, compresses the spring 45. When the plate 43 is 
released, the spring 45 urges the plate 43 toward the handle 26. The plate 
43 engages the lip 48, causing the lever 47 to tilt to its latching 
position as shown in solid line in FIG. 5. The arcuate sides of the square 
opening of the lever 47 engage the arm 22. The effective size of the 
opening in the direction parallel to the axis of the arm 22 becomes 
smaller than the cross section of the arm 22 due to the angular 
orientation assumed by the lever 47, thus preventing further movement. 
Accordingly, the jaws 27 and 30 firmly grip the tire therebetween. 
The spring 45 thus serves three purposes. First, it constitutes a linkage 
between the plate 43 and the jaw 30, meaning that when one grasps the 
plate 43 and moves it to the left or the right, the jaw 30 follows. 
Secondly, the spring 45 biases the jaw 30 against the side wall 15 of the 
tire 13 when one pushes against the plate 43. Finally, the spring 45 
causes self-engagement of the latching means 34. In other words, when the 
plate 43 is released, the spring 45 urges the plate 43 to the left and 
causes the lever 47 to assume its latching condition. 
When it is desired to release the target 20, the lever 47 is drawn against 
the plate 43, as shown in phantom in FIG. 5, thereby releasing the 
latching means 34. The lever 47 is held against the plate 43 and the two 
are drawn toward the handle 26. 
Mounted on the arm 22 adjacent the handle 26 is a spirit level 50 (FIGS. 2 
and 3) consisting of a vial containing liquid. By use of the level 50, the 
mechanic can make a slight adjustment in the orientation of the target 20 
to be sure that the arm 22 is horizontal. 
The target 20 further comprises a scale 60 comprising a rectangular sheet 
bent to form a rectangular plate 61 and a flange 62 normal thereto. The 
plate 61 bears parallel lines and numerals signifying distances inwardly 
from the right-hand edge of the plate 61. The scale 60 is slidably movable 
on the arm 23. To that end, the target 20 further comprises a pair of 
guides 65 and 75. Referring to FIG. 6, the guide 65 is made of a sheet 
metal strip bent to form a rectangular housing 66 having a rectangular 
opening 67, the width of which is slightly greater than the width of the 
arm 23. The longer dimension of the opening 67 is long enough to provide 
room for the arm 23 and an elongated rectangular nut 68. The housing 66 
has turned-down ends 69 to confine the nut 68. The guide 65 includes a 
pair of flanges 70 respectively riveted to the plate 61 and the flange 62. 
A thumb screw 71 passes through an opening in the housing 66 and is 
threaded into the nut 68 and further extends into an opening 23a in the 
arm 23, as will be further explained. 
The second guide 75 (FIGS. 1,2,7) is a metal strip bent to form a square 
housing 76 having a square opening therethrough, and a pair of attachment 
flanges 77 respectively riveted to the plate 61 and the flange 62. The 
dimensions of the opening in the housing 76 are slightly greater than the 
dimensions of the arm 23 so that the target 20 can slide freely 
therealong. 
The plate 61 is at an acute angle 80 with respect to a plane passing 
through the arms 22 and 23 (such plane being represented by the center 
line in FIG. 6). In an actual embodiment, the angle 80 was 26.degree.. 
To move the scale 60, the thumb screw 71 is loosened. The scale 60 is moved 
to a selected position in which the screw 71 is aligned with a selected 
one of the three openings 23a and then tightened so as to pass through 
such selected opening and engage an inner surface of the arm 23, as shown 
in FIGS. 6 and 7. Alternately, the scale 60 can be moved to a selected 
position in which the thumb screw 71 is not aligned with one of the 
openings 23a. The screw is tightened so that its end engages the exterior 
of the arm 23, thereby holding the scale 60 at such selected position. The 
first modus operandi insures that the scales of the two targets on 
opposite sides of the vehicle can be positioned at the same distance from 
a selected reference point. 
The target 20 is mounted on a selected tire in the manner previously 
described, that is, the jaws 27 and 30 are separated, slipped onto the 
selected tire and tightened. Because the target 20 engages both side 
walls, it can be located at an advantageous position beneath the hub 12 
and in back of the front tire 13. The plate 61 being at an obtuse angle 
can be oriented vertically even though the jaws 27 and 30 are not 
horizontal but more nearly radially oriented with respect to the tire. 
Referring to FIG. 1, the scale 60 is outside of and rearward of the 
cylinder defined by the tread surface 14. This is desirable because it is 
possible to measure the distance of the scale 60 from any selected part of 
the automobile 10 such as the body, the frame, the drive shaft or the side 
wall 15. The scale of many prior art targets is within the cylinder 
defined by the tread surface 14 and, therefore, such measurements are 
difficult to make. 
In FIG. 1, being outside of the cylinder of the tread surface means that 
the scale is behind the front tire 13. When the target 20 is mounted on a 
rear tire, being outside of the cylinder means it will be in front of the 
tire. 
The target depicted in FIG. 1 would be mountable on the right rear wheel 
also. The one to be mounted on the right front tire or on the left rear 
tire would have a reverse orientation. 
What has been described therefore is an improved target for use in track 
alignment of vehicles, the target being located outside the cylinder of 
the tread surface, to enable the scale itself to be place in a truly 
horizontal position and to enable the position of the scale to be slidably 
adjusted to any distance from any selected reference point on the vehicle.