Design and development of layout tool for machine shop use to locate point in precise reference to straight or bowed reference edg

Green, R. G.

English

NASA Technical Reports Server

* .  
c 
https://ntrs.nasa.gov/search.jsp?R=19710016669 2020-03-17T03:05:39+00:00Z
LAYOUT TOOL 
Filed Aug. 29, 1 
3,562,919 
Robert 6. Green. L 
States of America as 
5 Claims 
A 
A compact layout tool for machine shop use to locate 
a point in precise relationship to a straight or  arcuate ref- 
erence edge. The tool comprises a straight edge blade, and 
a parallelogram structure mounted on the blade. Two of 
the opposite corners of the parallelogram structure are held 
on the straight edge, one pivotally joined thereto and the 
other constrained to movement therealong. The other 
two corners lie on opposite sides of the strdight edge, and 
a pair of pins is mounted outwardly of these corners. 
When the pins engage a reference edge, the straight edge 
blade extends perpendicular to the reference edge. The 
parallelogram structure can be opened for large work- 
pieces, and can be collapsed for carrying the tool in a 
shirt pocket. 
ORIGIN OF INVENTION 
The invention described herein was made by an em- 
ployee of the United States Government and may be 
manufactured and used 'by or for the Government for 
Governmental purposes without the payment of any 
royalties thereon or therefor. 
BACKGROUND OF THE INVENTION 
(1) Field of the invention 
This invention relates to layout tools. 
( 2 )  Description of the prior s t  
Metal working often involves the layout of points on a 
workpiece in moderately accurate relationship to other 
points. For example, instrument panels are often formed 
with large holes through which a dial IS inserted. Mount- 
ing holes must be drilled at predetermined distances from 
such a dial hole, to receive screws that hold the dial instru- 
ment in place. A center head instrument is sometimes used 
for such layout work. It comprises a straight edge blade, 
and a V-shaped head centered on the blade edge. The 
ends of the V are held against the perimeter of the dial 
hole, and the straight edge then lies along a radius of the 
dial hole. Distances measured along the straight edge are 
distances measured precisely from the center of the dial 
hole. 
When V-shaped center heads are used, a set of several 
sizes usually must be provided for general shop use. This 
is because a small center head is inaccurate for large 
circles, while a large center head cannot fit into small 
circles. A set of heads has the disadvantage of large bulk 
and cost. In some types of work, the center heads must 
be used constantly, and it would be convenient if they 
could be carried in a shirt pocket. However, the fixed V 
configuration makes even one center head bulky and 
therefore inconvenient to  carry. 
OBJECTS AND SUMMARY OF THE 
INVENTION 
One object of the present invention is to provide a lay- 
out tool which provides accurate layout for a wide range 
of workpiece sizes. 
Another object is to provide a compact and economical 
multipurpose layout tool. 
5 
10 
15 
20 
25 
30 
35 
40 
45 
50 
55 
60 
65 
70 
In accordance with the present invention, a layout tool 
is provided which comprises a straight edge blade, and 
a parallelogram structure With equal sides. The parallelo- 
gram sides are formed by four elongated members which 
are pivotally joined to form four corners. One comer is 
pivotally joined to the straight edge blade, while the 
opposite comer is constrained to movement along the 
straight edge. The other two corners lie on opposite sides 
of the straight edge blade. Pins are fastened to two of the 
elongated members at points on opgosite sides of the 
straight edge. 
The tool can be used to establish a line which is perpen- 
dicular to a straight reference edge. This is accomplished 
by moving the pins against the reference edge. The 
straight edge of the blade is then perpendicular to the 
reference edge. In order to establish the straight edge 
blade along a line which is radial to a circular hole, the 
pins are moved against the perimeter of the hole. If the 
hole is small, the pins must be moved close together, SO 
the parallelogram is almost completely collapsed. If the 
hole is large, or the reference edge is straight, the pins 
are moved far apart to increase accuracy. The tool is gen- 
erally collapsed when it is to be carried in the pocket. 
In one embodiment of the invention, the straight edge 
is marked as a ruler, to enable distance measurements to 
be made. Also, the portion of the straight edge blade 
around the point where two parallelogram arms are 
pivoted on the blade is marked in degrees to indicate the 
angle of the arms. With these distance and angle mark- 
ings, the tool serves as a general purpose instrument, and 
can be used as a ruler or protractor. In still another em- 
bodiment of the invention, a scriber is provided which can 
be mounted on the straight edge. The scriber can be used 
to draw a line which is radial or concentric with a circular 
reference edge, or which is perpendicular or parallel to a 
straight reference edge. 
The novel features of the invention are set forth with 
particularity in the appended claims. The invention will 
best be understood from the following description when 
read in conjunction with the accompanying drawings. 
BRIEF DESCRIPTION OF THE DRAWINGS 
FIG. 1 is a plan view of a layout tool, showing it used 
FIG. 2 is a bottom elevation view of the tool of FIG. 1; 
FIG. 3 is an end elevation view of the tool of FIG. 1; 
FIG. 4 is an end elevation view of a scriber attachment, 
FIG. 5 is a side elevation view of the scriber of FIG. 4; 
FIG. 6 is a plan view of the tool of FIG. 1, showing its 
FIG. 7 is a plan view of the tool of FIG. 1, showing its 
on a workpiece with a circular aperture; 
for use on the tool of FIG. 1; 
use against a straight reference edge; and 
use in finding the center of a solid cylinder. 
DESCRIPTION OF THE PREFERRED 
EMBODIMENTS 
FIGS. 1, 2, and 3 illustrate a layout tool in an approxi- 
mately half-opened configuration. The tool comprises a 
blade 10 defining a straight edge 12 and a parallelogram 
structure I4 mounted thereon. The parallelogram structure 
comprises two arms 16 and 18 having inner ends which 
are pivotally joined to each other and to a protuberance 
20 on the blade at a pivot Z2. The parallelogram struc- 
ture also includes a pair of links 24 and 25 having inner 
ends pivotally joined to each other and to a slide bearing 
assembly 28. The slide bearing assembly is constrained to 
movement along a slot 30 formed in a slot bearing portion 
32 of the blade. The outer ends of the links are pivotally 
and 36 to the arms 16 and 88 of the parallelo- 
gram structure. 
3,562,919 
3 
where the inner ends of the arms 
are joined to form one parallelogram corner, and the slot 
30 which holds the slide bearing assembly that defines 
the location of the opposite parallelogram corner, are both 
in line, or aligned with, the straight edge 12 of the blade. 
The pivot points 34 and 36 are located on outer end por- 
tions of the arms, at positions which result in the sides 
of the parallelogram structure (being equal, so that the 
parallelogram is a rhombus. The sides of the parallelogram 
are measured between the pairs of adjacent pivot points 
34 and 22,22 and 36,36 and 2$, and 28 and 34. Two pins 
38 and 40 are mounted along the outer end portions of the 
arms 16 and 18 at the outer ends thereof. Because of the 
equal sides of the parallelogram, the angle between the 
straight edge 12 and either arm 16 or 18 is equal for any 
configuration of the parallelogram structure. Also, a line 
joining the pins 38 and 40 is perpendicular to the straight 
edge 12 for any configuration of the parallelogram. 
The slide bearing assembly 28 includes a locking screw 
42 which can be turned to lock the position of the bearing 
assembly at any desired place along the slot 30. With the 
locking screw 42 thus engaged, the configuration of the 
parallelogram structure 14 is fued. The layout tool can 
then be used in a variety of applications. One application, 
shown in FIG. 1, is the establishment of the straight edge 
12 along a radius of an aperture 44 formed in a workpiece 
46. This is accomplished by positioning the tool with the 
pins 38 and 40 placed against the perimeter of the aper- 
ture. This application of the layout tool is commonly 
encountered in the production of custom instrument panels, 
wherein the workpiece 46 is a plate in which the aperture 
has been formed to receive an instrument dial. Mounting 
holes for receiving screws that hold the instrument in 
place may have to be located at  predetermined distances 
from the edge of the aperture 44, as measured along a line 
which passes through the center of the aperture 44. This is 
accomplished by measuring a distance along the straight 
edge 12 from the edge of the aperture 44. 
One end 48 of the blade has ruler markings thereon. 
This facilitates the measurement of the distance between 
a point such as that shown at 50 and the edge of the aper- 
ture 44, and in a variety of other applications. A protrac- 
tor portion 52 is formed in the blade around the pivot 
point 22. An extension of the arm 16 is formed as a pointer 
53 which lies over the protractor portion. The protractor 
portion 52 carries angle markings for indicating the angle 
between the straight edge 12 and the arm 16 (either edge 
of the arm 16 can be used). This enables use of the in- 
strument for measuring angles, which is often required 
in layout work. 
The blade 10 and each of the two arms and two links 
may be formed from a sheet of steel or other stiff material. 
The pivots at  22, 34, and 36 are rivets inserted through 
holes formed in the links or arms. The bottom face of the 
arms 16 and 18 and the blade protuberance 20 have 
countersunk holes at pivots 34, 36 and 22 respectively. 
This allows the rivets to be formed flush against the bot- 
tom surface to prevent “catching” of the rivets on work- 
pieces. The pins 38 and 40. are formed so that their ends 
lie at the same distance below the blade 10. Since the 
rm 18 lies at  a slightly higher level than the other arm 
6, the pin 48 has a base portion 41 which is thicker than 
the base portion 43 of the other pin 38. 
The locking assembly 28 comprises a thin bearing pin 
54 which is enaged in a cutout border area 34 formed in 
the bottom surface of the blade around the slot. As a re- 
sult, the bearing pin §4 does not protrude below the bot- 
tom surface of the blade. A threaded rod, indicated at 55, 
is fixed to the bearing pin 54 and extends through holes in 
the links, so that its lower portion confines the corner of 
the parallelogram structure to movement along the slot. 
The upper portion at the rod 55 is pivotally engaged with 
holes in the links to provide pivotal connection, and is 
threadably engaged with the locking screw 42. Tightening 
of the locking screw 42 squeezes the links and blade be- 
tween the locking screw and bearing pin to fix the con- 
figuration of the tool. 
The layout tool is readily adaptable for a variety of 
object sizes and a variety of applications. FIG. 7 shows 
the tool being used to find the center of a relativeIy small 
cylinder 60. In order to find the center of the small cylin- 
logram structure is collapsed so that the 
are closer together than the diameter of 
the cylinder. The cylinder center can be marked by scrib- 
ing a line along the straight edge 1% and then rotating the 
layout tool approximately 90” and scribing another line. 
The intersection of the two lines is at  the center of the 
cylinder. The tool is useful for very small circular aper- 
tures and cylinders, since the pins can be moved very 
In the use of the layout tool for a very large aperture, 
or for a straight edge, the parallelogram structure should 
be extended. Extending the parallelgram structure so that 
the pins 38 and 40 are far apart increases the accuracy 
20 of location of the straight edge 12. FIG. 6 illustrates 
the use of the tool against a straight edge 62 of a work- 
piece, wherein the pins 38 and 46 are moved far apart. 
An impotrant feature of the layout tool is that it can be 
collapsed to a compact configuration. This is accom- 
25 plished by collapsing the tool toward the configuration of 
FIG. 7, and even further, so that the pins 38 and 40 are 
as close together as possible. The locking screw 42 may 
then be tightened to prevent accidental opening. The tool 
is then compact and, in moderate sizes wherein the blade 
30 is approximately six inches long, the tool may be readily 
carried in a shirt pocket. The tool is readily available for 
establishing perpendiculars, measuring angles and dis- 
tances, and in other applications. 
The layout tool can be constructed in a variety of con- 
35 figurations. For example, the arms and links can be 
made the same length, and the pins can form a part of 
the joints at 34 and 36. However, this limits the accuracy 
of the tool for large workpieces. Generally, it is preferable 
to place the pins approximately so far out as the joints 
40 34 and 36 between the arms and links, or even further 
as in the embodiment shown in the figures. It should be 
noted that a structure other than a precise geometrical 
parallelogram can be used, so long as two adjacent sides 
such as 24 and 26 are equal and the other two adjacent 
sides which are part of arms 16 and 18 are equal. Such a 
four sided figure, which somewhat resembles a parallelo- 
gram, may be referred to as parallelogram-type structure. 
FIGS. 4 and 5 illustrate a scriber attachment which is 
useful in the layout tool of the invention. The scriber 
50 attachment 64 comprises a body 66 with a slot-like aper- 
ture adapted to receive the blade 10 of the layout tool. A 
tightening screw 68 serves to fix the position of the scriber 
attachment along the straight edge blade. A point portion 
70 of the body has a sharp end which can scribe a line 
jj on metal. The scriber attachment is utilized by placing it 
on one end of the blade, so that it has a position such as 
that shown at 64A in FIG. 1. With the tightening screw 
48 tightened to hold the scriber attachment firmly in place 
on the blade, the pointer 70 can be used to scri 
60 a line such as that show in FIG. 1. The line 
is concentric to the apertu 
The scriber attachment be used in another man- 
ner, by loosening the tighting screw 68 and keeping the 
layout tool stationary. If the scriber attachment at  64A is 
65 moved along the blade 10, it scribes a line along the 
straight edge 12, which is radial to the aperture 44. The 
scriber attachment can be used in a similar manner when 
the Iayout tool is positioned against a straight edge as in 
FIG. 6 or is positioned against a cylinder as in FIG. 7. 
Although particular embodiments of the invention have 
been described and illustrated herein, it is recognized that 
modifcations and variations may readily occur to those 
skilled in the art, and, consequently, it is intended that 
the claims be interpreted to cover such modifications and 
15 close together. 
70 
75 equivalents. 
3,562,919 
What is claimed is: 
1. A layout tool comprising: 
a blade defining a straight edge; 
first and second arm members, each having an inner end 
and an outer end portion; 
means pivotally joining said inner ends of said arm 
members to each other and to said blade at a point 
in line with said straight edge; 
first and second link members, each having an inner 
end and an outer end portion; 
joint means constrained to movement along a line which 
is aligned with said straight edge, said joint means 
pivotally joining said inner ends of said link members 
to each other restraining them to positions along said 
line; 
means pivotally joining said outer end portions of said 
first and second arm members to said outer end por- 
tions of said first and second link members, respec- 
tively, at positions which define a four-sided figure 
with a first pair of adjacent sides of equal length and 
a second pair of adjacent sides of equal length, be- 
tween points of pivotal connection of said arm and 
link members to each other; 
a substantially cylindrical pin mounted at the outer 
end portions of two of said members whose outer end 
portions are spaced from each other when said four- 
sided figure is in an open configuration; and 
means for retaining said members in a fixed relative 
orientation. 
2. The layout tool described in claim 1 including: 
protractor means disposed about said means pivotally 
joining said inner ends of said arm members; and 
means disposed on one of said ann  members in in- 
dicating relationship with said protractor means, for 
indicating the angle of orientation of said arm mem- 
bers. 
3. The layout tool described in claim d including: 
a scriber; 
means for mounting said scriber on said blade, for 
movement parallel to said straight edge; and 
means for releasably fixing the position of said scribed 
along said blade, whereby to enable the scribing of 
lines both perpendicular and parallel to a reference 
edge. 
4. A layout tool comprising: 
a blade having a portion with a straight edge; 
5 
10 
15 
20 
25 
30 
35 
40 
a parallelogram-type structure having four elongated 
members, and means for coupling said members to 
form four pivotally joined corners; 
means for clamping said parallelogram-type structure 
in a fixed configuration and releasing it therefrom; 
means for holding said parallelogram-type structure to 
said blade with opposite first and second corners of 
said parrallelogram-type structure in line with said 
straight edge of said blade; 
scriber means; and 
means for fixing said scriber means to said blade, where- 
by to enable the scribing of a line parallel to a 
reference edge engaged by said pin means. 
5. A layout tool comprising: 
a blade having a portion with a straight edge; 
a parallelogram-type structure having four elongated 
members, and means for coupling said members to 
form four pivotally joined corners; 
means for clamping said parallelogram-type structure 
in a fixed configuration and releasing it therefrom; 
and 
means for holding said parallelogram-type structure to 
said blade with a first corner thereof pivotally joined 
to said blade at a point in line with said straight edge 
of said blade and a second comer in line with said 
straight edge; and 
angle markings disposed on said blade about said first 
corner, for indicating the angle between one of said 
elongated members and said straight edge. 
References Cited 
UNITED STATES PATENTS 
539,688 5/1895 Kolb _________-_____ 33-191 
608,183 SA898 Davis _ _ _ _ _ _ _ _ _ _ _ _ _ _  33-191 
650,799 5/1900: Sanders _ _ _ _ _ _ _ _ _ _ _  33-27(F) 
3,052,033 9/1962 Studt _ _ _ _ _ _ _ _ _ _ _ _  33-27(C) 
FOREIGN PATENTS 
159,761 4/1905 Germany _ _ _ _ _ _ _ _ _ _ _ _  33-189 
“American Machinist,” Apr. 22, 1948, p. 95. 
OTHER REFERENCES 
WILLIAM D. MARTIN, JR., Primary Examiner 
U.S. C1. X.R. 45 
33-27.42.75 


Layout tool Patent

Abstract

Similar works

Full text

Available Versions

NASA Technical Reports Server