System for determining angles for cabinet tops

A system and method for determining cutting lines for cabinet top joinery without measurement of angles apparatus for apparatus for positioning against walls between which a cabinet top is to be installed and a transfer device for establishing a distance between a selected points on the apparatus. A saw guide incorporates a linkage arrangement adapted for mating with the transfer device so as to establish a cutting angle which bisects the angle of intersection of the walls. Another mechanism is provided to automatically determine offset cutting angles using only the transfer device.

BACKGROUND OF THE INVENTION 
This invention relates to geometrical instruments and, more particularly, 
to a method and apparatus for transferring non-perpendicular angles in 
building construction to corresponding cutting angles. 
The method and apparatus of the present invention is particularly adapted 
for use in establishing cutting angles for cabinet tops. For example, in 
many modern style kitchens, it has become common to design structures 
which have obtuse angles rather than perpendicular walls. Cabinet tops for 
such kitchens are required to provide a continuous surface extending 
through such obtuse angles corners. Computation of the proper cutting 
angles to form joints for such tops is difficult and often beyond the 
capability of many cabinet installers. Accordingly, it is desirable to 
provide a method and apparatus for determining such angles with a minimum 
of skill. 
SUMMARY OF THE INVENTION 
The above and other disadvantages are overcome in an apparatus for 
determining cutting angles for cabinet tops traversing a corner in which 
first and second pivoting guides, each comprising a substantially straight 
elongated member having at least one end adapted to pivotably attach to 
one end of the other of the guides is provided for determining angular 
orientation of walls. Each of the guides has a connection point located a 
predetermined distance from the at least one end. An adjustable 
measurement transfer means including first and second relatively 
adjustable elements adapted for mating engagement with the connection 
point of the two guides is provided for determining the displacement 
between the guides. The adjustable elements have means for at least 
temporarily fixing the position of the elements so that the spacing 
between the connection points on the two guides is established by the 
position of the elements. 
In one embodiment, there is provided a saw guide which includes a 
parallelogram linkage and a first bar extending in a direction parallel to 
a saw cutting direction. A second bar is pivotably coupled to the first 
bar and oriented in a position for urging a top into a cutting position. A 
second bar forms one arm of the parallelogram linkage. The parallelogram 
linkage is further formed by third, fourth and fifth bars which are 
pivotably connected to the first and second bars with at least one 
pivotable point between the remaining bars being coupled for slidable 
positioning on the first bar whereby the angular orientation of the second 
bar with respect to the first bar is varied by sliding of the at least one 
pivotable point. The two remaining pivotable points of the parallelogram 
linkage include apertures adapted for receiving the relatively adjustable 
elements on the transfer measurement apparatus. When the at least one 
pivotable point is adjusted such that the adjustable elements mate with 
the two apertures in the remaining pivotable points, the angle defined by 
the first and second bars establishes a proper cutting angle for the 
cabinet top. This arrangement provides for an ability to cut a cabinet top 
at a proper angle bisecting the angle defined by mating walls without the 
necessity of actually measuring the angle or computing the angle bisecting 
the walls. 
In another embodiment there is provided an apparatus for actually 
determining cutting angles or for determining cutting set back dimensions 
using the measurement transfer device. In this embodiment, first and 
second sheets having pivotable connection at corresponding corners are 
provided with at least one of the sheets having a plurality of scales 
formed on its surface. The other of the sheets has a plurality of lines 
corresponding to the scales such that the overlapping intersection of the 
soales and the lines defines set back dimensions. The sheets have 
apertures corresponding to the connection points on the first and second 
pivoting guides so that the adjustable elements can be inserted in the 
apertures to properly position the angular orientation of the two sheets 
with respect to each other. When the measurement transfer device is 
positioned so as to lock the two sheets in locked position, the 
intersection of the lines on one sheet with the linear scales on the other 
sheet provide an offset cutting dimension which will allow the cabinet top 
to be cut so that the joining angle between two tops traversing a corner 
will bisect a corner.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring now to FIG. 1, there is shown a first part of the apparatus for 
determining cutting angles for cabinet tops. The apparatus includes first 
and second pivoting guides 10 and 14 each comprising a substantially 
straight elongated member which may be shaped as a rectangular flat 
plate-like member. The members 10 and 14 are each provided with apertures 
16 at corresponding corners which enable the members to be pivotably 
attached to each other at at least one end of the members. The attachment 
may be by means of a pin passing through the apertures 16. At 
predetermined distances from the ends 18 and 20 of the respective ones of 
the members 10 and 14 there are provided connection points 22 and 24 which 
may take the form of additional apertures drilled or formed in the 
plate-like members 10 and 14. The two members 10 and 14 can be held in 
fixed position by an adjustable measurement transfer means 25 illustrated 
as a threaded rod 26 having relatively adjustable elements 28 and 30 
threadedly connected to each end thereof. FIG. 2 illustrates in more 
detail the adjustable measurement transfer means 25 and shows two 
depending pins 32 and 34 dimensioned to fit within the apertures 22 and 24 
in the members 10 and 14. The elements 28 and 30 can be moved along the 
threaded rod 26 by loosening the restraining nuts 36. Once the two members 
10 and 14 have been positioned in an area in which a cabinet is to be 
installed and held firmly against a wall surface, the rod 26 can be 
positioned with the members 28 and 20 arranged so that the pins 32 and 34 
can be inserted in the apertures 22 and 24. The nuts 36 are then tightened 
to hold the elements 28 and 30 in fixed position. 
In some instances, the walls may be arranged such that the members 10 and 
14 can not be abutted squarely against the wall surface. In such 
situations, additional extensions 38 and 40 may be attached to the members 
10 and 14 to provide a longer bearing surface. In a preferred embodiment, 
the members 38 and 40 have key ways 41 which are adapted to mate precisely 
with keys 43 formed on the upper surfaces of members 10 and 14. The 
members 38 and 40 can then be slid onto the surfaces of members 10 and 14 
and adjusted to any desired dimension. Once the angular orientation of 
members 10 and 14 has been established and the elements 28 and 30 locked 
in position on the threaded bar 26, the threaded bar 26 then operates as a 
transferable measuring device to enable cutting of cabinet tops so as to 
fit within the angle defined by the walls from which the measurement was 
derived. It will be appreciated that for two cabinet tops which are to be 
joined to traverse the angle defined by the two walls, the two tops should 
be cut at an angle which bisects the angle defined by the mating walls. 
This angle is indicated by the line 42. It will be appreciated from the 
view of FIG. 1 that the angle of line 42 is not directly measured by the 
apparatus shown in FIG. 1 since it is a bisector of the angle defined by 
the mating walls. In general, it has been required that the actual angle 
be measured and that trigometric functions be employed to determine the 
angle defined by the line 42. The present invention obviates this 
requirement for actual angle measurement while providing an apparatus that 
precisely defines the angle defined by line 42 for purposes of cutting 
cabinet tops or other members for insertion into angles defined by mating 
walls. 
Turning now to FIG. 3, there is shown one apparatus which enables the angle 
defined by the line 42 to be directly measured and alternatively to obtain 
a cutback dimension for a cabinet top without actually measuring the 
angles defined by the line 42. FIG. 3 illustrates a drafting aid 
comprising first and second flat sheets 44 and 46 having a pivotable 
connection at corresponding corners as indicated at point 48. A 
predetermined distance from ends 50 and 52 of the sheets 44 and 46 there 
are provided apertures 54 and 56 which correspond to the apertures 22 and 
24 in the angle gage apparatus members 10 and 14. When a pin is inserted 
in the apertures 48 connecting the two sheets 44 and 46, the measurement 
transfer means 25 can be utilized to position the angular orientation of 
the two sheets 44 and 46 so that the actual angle at which a line 42 need 
be cut on a cabinet top can be determined. Note that the transfer means 
including the rod 46 and two elements 28 and 30 is positioned on the two 
sheets so that the pins 32 and 34 are inserted in the apertures 54 and 56. 
An angle gage is inscribed on the sheet 44 at 58 so that the angle at 
which the line 42 is to be cut with respect to the walls can be obtained 
by the intersection of the edge 52 of sheet 46 with the angle gage 58. 
The sheet 44 is also provided with a plurality of scales representing 
offset dimensions from a line perpendicular to one of the walls so that 
the cabinet top may be cut by a measurement of an offset dimension rather 
than actual determination of an angle. For example, for a twelve inch wide 
cabinet top, the scale 60 provides set back dimension from a line 
perpendicular to one of the walls which enables an operator to measure a 
dimension from an edge of a cabinet top and cut from a back corner of the 
cabinet top to that offset dimension to thus directly form the proper 
angle aligning with the line 42 without having to actually determine the 
angle. Note that the offset dimension is not determined by the 
intersection of the edge 52 with the line 60 but by the intersection of 
the line 62 with the line 60. The line 62 corresponds to a cabinet top 
with the same width as that represented by line 60. Since each of the 
cabinet tops is desirably cut so as to follow the line 42, i.e., to bisect 
the corner angle, each top is cutback 221/2 degrees rather than the 
illustrated 45 degrees. Different width tops provide slightly different 
offsets as is illustrated by the lines 60A, 60B, 62A and 62B. It should be 
noted that additional apertures may be provided in the sheets 44 and 46 
and also in the members 10 and 14 for obtaining measurement for more acute 
angles. 
Turning now to FIG. 4 there is shown a saw attachment or a guide 
arrangement including a parallelogram linkage which allows dimensions 
obtained from the guides 10 and 14 to be used directly for cutting of 
cabinet tops without having to actually measure or determine dimensions 
using the drafting guides of FIG. 3. The saw guide includes a first bar 64 
which extends in a direction parallel to a saw cutting direction as is 
indicated by the position of a saw blade 66 on a table saw table 68. The 
bar 64 is provided with a slot extending over a relatively large dimension 
thereof for purposes which will become apparent. A second bar 72 is 
pivotably connected to the bar 64 at pivot point 74. The bar 72 is 
oriented in a position for urging a cabinet top into a cutting position 
for cutting with saw blade 66. The bar 72 forms one arm of the 
parallelogram linkage with the third, fourth and fifth arms being defined 
by bars 76, 78 and 80. The bar 76 is pivotably connected to pivot point 74 
and also pivotably connected to bar 78. Bar 78 is additionally pivoted to 
bar 80 at a pivot point 82, which pivot point 82 is also slidably 
connected in the slot 70 of bar 64. The bar 80 is connected to pivot about 
point 82 and also is pivotably connected to bar 72 at point 84. 
A cabinet to be cut is properly oriented with respect to the saw blade 66 
by the angular orientation of bar 72. The angular orientation of bar 62 is 
controlled by the position of pivot point 82 in slot 70. This pivot point 
position can be controlled by the relative position of pivot point 84 and 
pivot point 86 at the junction of bars 76 and 78. At each of the pivot 
points 84 and 86, there is provided apertures for receiving the pins 32 
and 34 on the transfer measurement device 25. Since the position of the 
elements 28 and 30 are fixed by the use of gaging means of FIG. 1 the 
position of pivot point 82 can be adjusted so that the pins 32 and 34 fit 
into the apertures at pivot points 84 and 86. When this position is 
achieved, the cabinet is angled so that the saw blade will effect a cut 
which will cause the end of the cabinet top to lie along the line 42. The 
apparatus of FIG. 4 therefore provides a saw guide which allows the 
cabinet top to be cut without having to determine any of the angular 
dimensions necessary to cut the top so that a joint is formed along the 
line 42. Thus, the apparatus of the present invention enables anyone 
having ordinary carpentry skills to accurately determine and cut cabinet 
tops or other members so as to form a joint which bisects an angle without 
the necessity of having any trigometric knowledge of the method of 
obtaining the proper cutting angles. 
A support for the saw attachment is indicated at 90 and comprises a flat 
plate and angle which can be attached to table 68 for supporting the saw 
guide for motion toward blade 66. 
While the invention has been described in what is presently considered a 
preferred embodiment, other modifications and variations of the system 
will become apparent to those having ordinary skill in the art. 
Accordingly, it is intended that the invention not be limited to the 
specific embodiment but be interpreted within the spirit and scope of the 
appended claims.