Tape measure assembly

A tape measure assembly with a ridge that is disposed along an edge of its housing and is generally perpendicular to the housing's spooling axis. The ridge has a rigidly placed working surface oriented perpendicularly with respect to an outer surface of the housing that is normal to the spooling axis. At least two portions of the working surface extend beyond the outer surface in a direction parallel with the spooling axis, and the working surface and the outer surface define a volume that surrounds the intersection of two generally perpendicular planes. Angle measurement markings can be disposed along a second edge of the housing, a notch can be formed at a center defined by the angle markings adjacent the first edge, and/or a second edge can form a right angle with the intersection of the two generally perpendicular planes.

FIELD OF THE INVENTION 
The present invention relates to a tape measure assembly that permits the 
measurement of right angles or other angles in addition to the measurement 
of lengths. 
BACKGROUND OF THE INVENTION 
Tape measures are probably the most frequently used measuring tools in 
carpentry, although other measuring tools are also commonly needed, 
particularly set squares and protractors. While attempts have been made to 
combine these measuring tools with tape measures, many of the resulting 
compound tools are cumbersome, impractical, or otherwise deficient. And 
none of them appears to have found widespread use in woodworking or in 
other trades. 
SUMMARY OF THE INVENTION 
In one general aspect, the invention features a tape measure assembly with 
a ridge that is disposed along an edge of its housing and is generally 
perpendicular to the housing's spooling axis. The ridge has a rigidly 
placed working surface oriented perpendicularly with respect to an outer 
surface of the housing that is normal to the spooling axis. At least two 
portions of the working surface extend beyond the outer surface in a 
direction parallel with the spooling axis, and the working surface and the 
outer surface define a volume that surrounds the intersection of two 
generally perpendicular planes. 
In preferred embodiments, angle measurement markings can be disposed along 
a second edge of the housing, a notch can be formed at a center defined by 
the angle markings adjacent the first edge, and/or a second edge can form 
a right angle with the intersection of the two generally perpendicular 
planes. A detachable portion bearing the ridge can be attached to the 
housing, and an attachment mechanism can be mounted on the detachable 
portion to attach it to remaining portions of the tape measure assembly. 
The detachable portion can include a generally planar area perpendicular 
to the plane of the ridge, and the ridge can be retractable in to the 
housing. The attachment mechanism can include clips mounted on the planar 
area. The blade opening can be adjacent another edge, generally parallel 
to and opposite the first edge. A pen clip can be attached to the housing, 
and this pen clip can be oriented to hold a pen parallel with the spooling 
axis. The overall area of the tape measure assembly, at its widest point 
viewed from the spooling axis, can be less than about twice the area of 
the coil when the tape is fully retracted. 
In another general aspect, the invention features an attachment for a tape 
measure that includes a generally rectangular plate having a ridge mounted 
on the plate and being rigidly placed in an orientation that is generally 
perpendicular to a first side of the plate. The ridge has a working 
surface, and at least a portion of the working surface extends beyond the 
remaining parts of the plate. The attachment also includes an attachment 
mechanism mounted on a second side of the plate, to attach the second side 
of the plate to a side of the tape measure. 
In preferred embodiments, an edge of the plate can be perpendicular to the 
ridge, angle markings can be provided along the second edge, and/or a 
center notch can be cut out of the plate adjacent the ridge. The 
attachment can be constructed to leave the blade opening unobstructed when 
it is attached to the tape measure, and the attachment mechanism can 
include clips. 
In a further general aspect, the invention features a method of defining 
positions for marking a work piece using a tape measure assembly. The 
method includes holding at least a portion of a tape measure blade in a 
coil about a spooling axis in a housing of the tape measure assembly, and 
contacting a working surface of a ridge of the tape measure assembly to an 
end of the work piece, where the working surface extends in a direction 
generally perpendicular to the spooling axis. Two reference points are 
provided on a surface of the work piece that is normal to the spooling 
axis and perpendicular to the plane of the end of the work piece. 
In preferred embodiments, the two points can be in alignment with an edge 
of the tape measure assembly that is perpendicular to the edge of the work 
piece, and/or they can be in alignment with a line that is at an acute 
angle with respect to the edge of the work piece. The method can also 
include a step of extracting the blade from the tape measure assembly, 
which overlaps in time with the step of providing. 
Embodiments of tape measure assemblies according to the invention can be 
advantageous in that they permit a carpenter to make a variety of 
additional measurements and marks, such as right angle cut lines or acute 
angle cut lines, without requiring him or her to carry additional 
instruments or a cumbersome tape measure attachment. This can save the 
carpenter time walking to and from his tool chest or truck, and it may 
also help to avoid the temptation to "eyeball" a cut, since an appropriate 
tools is always available. The result is that embodiments according to the 
invention can make a carpenter's work more efficient, and may even improve 
its quality. Embodiments according to the invention can be made to be 
simple and lightweight, while adding very little bulk to a tape measure, 
and without requiring any moving parts. In certain instances, the tape 
measure assembly may also allow the carpenter to make measurements using 
the assembly's ridge as a second end hook.

DETAILED DESCRIPTION 
Referring to FIGS. 1-4, an illustrative embodiment of the invention 
includes a tape measure assembly 10 that can comprise a tape measure 
accessory 12 attached to a standard tape measure 14. Alternatively, the 
assembly can include a special-purpose tape measure with the additional 
features of the accessory incorporated into its housing. 
As is well known, a tape measure 14 generally includes a housing 20, a 
blade 22, and an end hook 24 attached to one end of the blade. The blade 
passes through a blade opening 28 in the housing, and has marks 26 along 
its length, typically at regular intervals. The end of the blade opposite 
the end hook is a generally attached, such as by interlocking notches 32, 
to a retraction mechanism, which is typically a spring 30 (see FIG. 4). 
Other types of retraction mechanisms, such as cranks, are used in place of 
a spring in some tape measures, and the shapes and sizes of the housings 
of tape measures vary, with some housings only partially surrounding the 
coiled tape. It is contemplated that embodiments of the invention can be 
designed to suit a wide variety of tape measure designs. 
The tape measure assembly 10 includes a ridge 34 that is mounted along a 
first edge of the housing 20 whose axis 36 is generally perpendicular to a 
spooling axis 38 of the tape measure 14. A flat working surface 40 is 
oriented on one side of the ridge in a plane generally parallel to the 
spooling axis 38. The ridge can be attached to the tape measure housing 
itself, or it can be attached to a plate 42, which is attached to the tape 
measure by an attachment mechanism, which can include clips 46, 48, 50. 
The ridge can also be retractable into the assembly, such as by sliding or 
pivoting as shown in phantom in FIG. 4, although it should be mounted to 
the housing such that it can be placed in a rigid relationship with 
respect to the housing at least when measurements are to be performed. 
A protractor area 52 is provided on a surface 54 of the plate 42 (or a 
corresponding housing portion) that is oriented in a plane normal to the 
spooling axis 38. The angle markings face away from the ridge 34. The 
protractor area includes a series of angle marks 56 along a second edge 64 
adjacent the first edge and/or a third edge 65 opposite the first edge. 
Each angle mark indicates an angle between the axis 36 of the first edge, 
and a line joining that angle mark with a center or apex 60 (see FIG. 2). 
A notch 62 is cut out of a fourth edge 66 of the plate opposite the second 
edge 64 with respect to the ridge in such a way as to surround the 
location of the apex 60. Note that a curved corner 57 between the second 
and third edges tends to make measurement of angles around 45.degree. 
somewhat more precise. 
One or both of the second and fourth edges 64, 66, which are both adjacent 
the ridge 34, can define a right angle with respect to the axis 36 of the 
first edge, and a pencil clip can be attached to the tape measure 14, to 
the plate 42, or to the attachment mechanism (e.g., to one of the clips 
50). The pencil clip 70 includes two resilient jaws 72, 74, which hold a 
pen or pencil 76 in an orientation that is generally parallel to the 
spooling axis 38, at a predetermined distance from the ridge. The pencil 
clip may be slidably mounted so that its distance from the ridge can vary, 
and it can also be made to pivot so that the pen can point in a direction 
perpendicular to the spooling axis. 
Referring to FIGS. 5 and 6, in a variant, a tape measure accessory 80 
includes a plate 88 that has a two-part ridge made up of first and second 
ridge portions 84, 86 that extend away from a first side of the plate 
along a first of its edges. The ridge portions have an inward-facing 
working surface, which is disposed in a plane that is generally 
perpendicular to the plane of the plate. The working surface extends 
beyond the remaining portions of the assembly, to allow it to bear against 
an edge, such as a board edge. 
The working surface does not need to be continuous, but its orientation 
should be defined by at least two points. The edge does not need to be 
continuous either, but it should also serve to define the position of the 
two points. Similarly, the plate does not have to be continuous, but 
should include at least portions that define a generally planar surface on 
the first side of the plate. 
On a second side of the plate, an adhesive 90, such as a piece of foam 
tape, is provided to attach the accessory 80 to a tape measure. A center 
mark 92 is provided on a second edge of the plate 88 at one end of the 
ridge directly above the working surface, and angle markings 94 are 
provided on a third edge opposite the outer mark. The angle markings can 
also extend onto a fourth edge of the plate opposite the ridge. A 
detachable coupling such as a hook-and-loop fastener can be used in place 
of the adhesive. 
Preferably, the overall size of the accessory does not expand the size of 
the tape measure assembly much. It should be generally rectangular or 
otherwise generally match the shape of the tape measure. And it should not 
extend the area of the tape measure assembly, at its widest point viewed 
from the spooling axis, by more than about 50%, with 25% or less being 
preferable. Where the capabilities of the accessory are built into the 
housing, the overall area of the tape measure accessory should not be 
significantly larger than twice the area of the tape in its spooled-up 
position within the housing, with 50% or less being preferable. 
In operation, referring to FIGS. 1-6, a carpenter employing the improved 
tape measure assembly 10 may use it in much the same way he or she would 
have used a tape measure not equipped with features according to the 
invention, but he or she can also use it to mark right angles and other 
acute angles. To mark a right angle, the carpenter orients the tape 
measure assembly 10 with the surface of the plate beyond which the ridge 
extends held downwardly, rests it onto a surface of an object to be 
measured, such as a board 100, and aligns the working surface 40 of the 
ridge 34 against the end of the board (see FIGS. 2 and 4). Put in 
geometric terms, the working surface and the surface of the plate from 
which the ridge extend together define a volume outside the housing that 
surrounds the intersection of two generally perpendicular planes, which 
can be the planes of the top and end of the board. The front and/or rear 
edges 64, 66 will now be precisely perpendicular to the edge of the board, 
so the carpenter can simply scribe a straight line along one of those 
edges, and this line will be at a right angle with respect to the edge of 
the board. For small stock, such as moldings, this line may suffice as a 
cut line for the full width of the board. By switching to the other edge 
of the board and marking two lines, the tape measure assembly can be used 
to provide a cut line across a board that is as much as twice the width of 
the plate, although this cut line may not be straight if the board is 
warped or otherwise not rectangular. With larger boards, scribed right 
angles drawn from each edge may suffice as a starting point for a rough 
cut, or the gap between them can be filled in using part of the assembly 
as a straight edge. 
The tape 22 can be used to determine the positions of the right angle 
lines. A line can even be scribed without moving the tape measure after 
the position of a desired right angle is determined. In particular, if the 
tape measure opening is unobstructed by the accessory when it is in its 
operating position, the tape can be extended to the end of the board while 
the tape measure assembly rests on the board in its scribing position. If 
the tape opening 28 is adjacent the edge of the tape measure assembly 10 
that is being used to scribe the right angle marks, the measurement will 
be measured from the same point as it usually is. By locking the tape, a 
carpenter can also scribe the same line repeatedly on a series of boards, 
with each line being at the same distance from the end of its respective 
board. 
To mark angles other than 90.degree., the carpenter begins by aligning the 
notch 62 with the apex or center 60 of the desired angle and marks it, if 
it is not already marked. He or she can then make a second mark in 
alignment with the angle mark 56 corresponding to the desired angle 
magnitude. Typically the available angles will range from 0.degree. to 
45.degree., if only one edge is marked. Once the carpenter has made his or 
her marks, a straight line can be drawn between the center mark 60 and the 
second mark. This line may be traced with another straight edge, or an 
edge of the tape measure assembly, such as the ridge 34. To facilitate 
tracing lines for angles, the ridge can be made to be somewhat longer than 
the edge to which it is connected. Note that the angle marks on the tape 
measure assembly can also be used to measure unknown angles defined by 
preexisting lines. 
If the tape measure 14 is oriented with respect to the ridge 34 such that 
the tape 22 extends outwardly in a direction normal to the plane of the 
working surface 40, the ridge 34 can act as a useful second end hook. By 
placing the working surface against the end of a long board to be 
measured, an individual carpenter can pull the tape out and hook the end 
hook 24 on the other end of the board, and then return to the tape measure 
to read the length of the board. In some instances, this type of operation 
may permit an individual carpenter to measure relatively long boards 
without having to rely on the friction between the small hook and the 
board end while the tape is being retracted. This method of operation is 
less likely to result in the end hook slipping off the end of the board 
and retracting into the tape measure. To allow the tape measure assembly 
10 to be used in this manner, it is preferable to design the position of 
the working surface 40 to correspond exactly with the position of the rear 
edge of the tape measure, so that the tape measure's "inside measurement" 
number can be added to the number obtained from the tape. 
Some measurements are made from an edge that is not perpendicular with the 
direction of the measurement. For this reason, embodiments of the 
invention advantageously permit the tape measure to pivot with respect to 
the plate, so the ridge can be used as a slanted end hook. This may be 
achieved by mounting the attaching mechanism, such as the adhesive 90, on 
a turntable 96 in the plate 88 (see FIGS. 5 and 6). 
The pen clip 70 can allow a carpenter to draw lines parallel to the edge of 
a board 100, or to draw segments of circles. To draw a line parallel to 
the edge of the board, the tape measure assembly 10 can be slid along the 
end of the board, with the working surface 40 kept in alignment with the 
end of the board. This will result in the pen marking a line parallel to 
the board end, at a distance from the end defined by the position of the 
pen clip. By slidably mounting the pen clip on the assembly or adjusting 
the turntable 96, this distance can be varied. With the blade 22 locked, 
it is also possible to draw lines further from the board edge in a similar 
manner using the end hook as a guide, instead of the ridge. This can be 
done by twisting the tape, or orienting the pen clip at an angle that is 
perpendicular to the length of the blade. To draw circular segments, the 
end hook can be hooked to a nail or other protrusion, with the blade 
locked, and the assembly can then be moved through an arc in such a way as 
to keep the blade extended from the nail while maintaining the pen 76 on 
the surface to be marked. 
The present invention has now been described in connection with a number of 
specific embodiments thereof. However, numerous modifications which are 
contemplated as falling within the scope of the present invention should 
now be apparent to those skilled in the art. Therefore, it is intended 
that the scope of the present invention be limited only by the scope of 
the claims appended hereto.