Compound curvature cutting machine

A machine for cutting compound curvature surfaces on a workpiece by a linear or longitudinally extending straight line cutting element that is adjustably movable relative to the workpiece located on a bed of the machine. The cutting element is relatively movable or adjustable to the machine bed in any one of five variable axes or directions, as well as movable or adjustable about any two or more of the five axes or directions of movability and adjustability.

This invention relates to a compound curvature cutting machine whereby 
compound curvature surfaces having a plurality of variable curvature axes 
may be formed on the surface of a workpiece, and more specifically, a 
machine for forming variable compound curvature surfaces on low density 
materials such as, but not limited to, composite or metallic honeycomb, 
various foamed plastics, and low density wood and pressed wood products. 
In recent years the advanced structural design arts have featured stiff 
composite envelopes stabilized with sound absorbing, low density fillers 
having high stength/weight ratios; the fillers including shapes formed 
from such materials as composite or metallic honeycombs, various foamed 
plastics, and low density wood in compressed wood products as well as 
other low density materials. A great disadvantage of the advanced 
structural designs has been the excessive cost of producing them, 
principally due to the difficulties of contouring or shaping the filler 
bodies. 
Machines to accomplish a portion of the overall achievements of this 
invention are known in the prior art as exemplified by U.S. Pat. No. 
2,856,672 issued to Gregg et al, and which is limited to honeycomb or 
other workpieces having a patterned set of holes or passages therethrough. 
Also, such machines require specially formed workpiece holding tooling for 
each operation on each configuration of workpiece. By permitting the 
cutting element to operate in its conventional straight-line manner and 
environment (i.e., without bending or deflecting the cutting element from 
its normal operating straight-line cutting path) through the avenue of 
relative adjustment between the straight-line cutting path and the 
workpiece surface as accomplished by the machine of this invention, it is 
found that the quantity of special tooling for cutting compound surfaces 
on various workpieces, and the expense or cost therefor, are substantially 
reduced. 
Accordingly, it is the object of this invention to provide multiple axes 
cutting equipment whereby compound curvature surfaces can be generated on 
a workpiece with a minimum number of cutting operations and special 
tooling. 
Another object of this invention is to provide multiple axes cutting 
equipment whereby compound curvature surfaces can be generated on a 
workpiece with closer tolerances and smoother finish surfaces. 
Still another object of this invention is to provide multiple axes cutting 
equipment with which compound curvature surfaces can be generated on a 
workpiece more efficiently

Generally stated, this invention comprises a gantry arrangement combined 
with a machine bed and drivingly interconnected so that relative motion 
between the gantry and bed can be accomplished in a direction 
longitudinally to the bed. A cutting means is mounted to the gantry 
structure to extend width-wise across the machine bed and includes means 
for four axes adjustment of the cutting element or member relative to the 
machine bed: the four axes adjustment control means being mounted on the 
gantry and when combined with the horizontal movement of the gantry 
longitudinally relative to the machine bed constitutes a cutting machine 
capable of movement or adjustment in up to five axes. The gantry mounted 
cutting member may be of a continuous band saw blade of flat or round 
cross-sectional configuration and utilizing various tooth and edge shapes 
as well as abrasives bonded on cutting materials, or a hot wire consisting 
of a heated cutting wire; all these cutting devices being well known in 
the prior art and forming a straight-line cutting element. The specific 
cutting element or member chosen or utilized will depend upon the 
workpiece material and the cutting method desired since each cutting 
method will have limitations of smoothness, tolerance and suitability of 
finished workpiece usage. 
More specifically, with reference to FIG. 1 of the drawings, the machine 10 
of this invention comprises a gantry assembly 11 connected to a machine 
bed assembly 12 in a manner to permit relative movement therebetween: that 
is, the gantry may be located in a level and stationary manner relative to 
the location floor with the bed assembly 12 movable longitudinally (as 
seen in FIG. 1) relative to the gantry, or vice versa, the bed assembly 12 
may be located in a level and stationary relationship at the floor 
location with the gantry 11 moveble relative to bed assembly 12. The 
preferred embodiment, in that shown in the drawings, is that of the latter 
arrangement whereby the gantry 11 is movable relative to the fixed bed 
assembly 12. 
A cutting means assembly 13 containing a cutting element 14 (such as for 
example a continuous band saw of any of the available cross-sectional 
shapes and containing any of a variety of external surface configurations 
for removal and/or surface finishing of the workpiece involved, or a 
conventional hot-wire cutting element) is mounted to gantry 11 in such 
manner that adjustment or movement of cutting element 14 relative to the 
surface of bed assembly 12 may be made in four of the five axes that 
cutting element 14 is capable of moving relative to the surface of bed 
assembly 12 with the machine of this invention described below; the fifth 
axis capability of this machine being the longitudinal movement of cutting 
element 14 relative to the surface of bed assembly 12 as also explained in 
more detail hereinafter. 
Before proceeding with description of specific details for various axis 
adjustments of the depicted embodiment of this invention, reference is 
first made to FIGS. 2A through 2E for schematic definition of the various 
axis movements or adjustments. FIG. 2A depicts the relative movement 
between bed assembly 12 and cutting element 14 in a longitudinal and 
parallel manner which in the preferred embodiment (as stated above) the 
cutting element 14 moves relative to bed assembly 12. This movement is 
considered to be movement or adjustment along the X-axis. 
FIG. 2B shows the relative vertical movement or travel between cutting 
element 14 and machine bed 12 occasioned by vertical travel of cutting 
element 14 on the gantry assembly 11. This movement is considered as 
adjustment or movement along the Y-axis. 
FIG. 2C is similar to FIG. 2B, but with relative vertical movement or 
travel between only one end of the cutting element 14 and machine bed 12 
by vertical travel of only one end of the cutting element 14 on the gantry 
assembly 11 while the opposite end of the cutting element 14 is vertically 
stationary relative to the gantry assembly 11. This movement is known as 
an Angle-a adjustment, or adjustment around the X-axis. Likewise, movement 
or adjustment in this mode can consist of simultaneous movement of both 
ends of cutting element 14 in opposite directions or both sides in the 
same direction differentially for such Angle-a adjustment or movement. 
FIG. 2D shows adjustment where pivotal movement of one end of cutting 
element 14 relative to its other end, the swinging movement of one end of 
cutting element 14 in being a horizontal and parallel direction relative 
to the machine bed 12; which movement is known as an Angle-b adjustment, 
or adjustment around the Y-axis. 
FIG. 2E depicts the deflection or tilt of the cutting element 14 relative 
to the vertical axis of gantry assembly 11; such deflection or tilt axis 
being perpendicular to the vertical axis of the gantry 11 when cutting 
element 14 extends laterally across bed 12 and parallel thereto. This type 
of movement is identified as or called an Angle-c adjustment around the 
Z-axis. 
With regard to the adjustment depicted in FIG. 2A, or movement along the 
X-axis, reference is now made specifically to FIGS. 1 and 5. Gantry 
assembly 11 comprises at least four vertical column members 15 rigidly 
interconnected at their upper ends by horizontal members 16. The lower 
ends of vertical column members 15 having depending or extending therefrom 
a guideway means 17 adapted to fit on and be directed by guiderails 18 
mounted longitudinally along opposite edges of bed assembly 12. Members 15 
and 16 of gantry assembly 11 constitute somewhat of a frame or saddle for 
a mounting or holding assembly for the cutting means assembly 13; such 
mounting or holding assembly comprising a pair of vertical column members 
19 interconnected with a horizontal member 20 extending over and secured 
to a pair of opposite horizontal members 16 of the gantry 11 frame. The 
details of mounting and adjustment of the cutting means assembly 13 to the 
vertical members 19 for adjustments relative to bed 12 will be explained 
in more detail thereinafter. 
Horizontal movement of gantry 11 relative to bed 12 (adjustment along the 
X-axis) is accomplished by a motor or power means 21 mounted on one of the 
horizontal members 16 for rotationally driving a shaft 22 that extends 
substantially parallel to said horizontal member 16. Shaft 22 in turn is 
drivingly connected to a pair of vertical shafts 23 through their 
appropriate right angle gear means 24; the vertical shafts 23 extending 
downwardly to the proximity of the bed 12 and each having a pinion gear 25 
that in turn engages with a rack 26 mounted on each side of the bed 
assembly 12. Motor 21 is reversible, and control therefor, which is not 
shown and forms no part of this invention, may be under the manual control 
of the machine operator or any type of numerical control or other types of 
machine tool control adapted to operate a conventional type of machine 
tool of this invention. Thusly, it can be seen that horizontal travel or 
adjustment of the gantry assembly 11 relative to the bed assembly 12 is 
accomplished so that all four vertical column members 15 are moved 
uniformly when adjustment or movement of the cutting means assembly 13, 
and hence cutting element 14, relative to bed 12 along the X-axis of the 
machine is made. 
For description of details that permit the vertical travel of cutting means 
assembly 13 relative to bed 12 (i.e., adjustment along the Y-axis) 
reference is now made to FIGS. 1, 3, 4, and 7. 
A screw threaded shaft 27 is mounted vertically relative to each vertical 
column member 19 and engages a threaded nut or ball screw means 28 
contained within a frame means 29, which in turn has appropriate straps 30 
and guide roller devices 31 extending therefrom and arranged around 
vertical column members 19 in such manner that the guide rollers 31 will 
be in rolling contact therewith as shaft 27 is rotated in either direction 
to cause each of the frame means 29, and its associated nut 28, to move 
vertically upward or downward relative to vertical columns 19 depending 
upon which direction shaft 27 is rotated. Each frame means 29 has a shelf 
or ledge assembly 32a or 32b rigidly connected thereto on which the 
cutting means assembly 13 is mounted or connected to so that as shafts 27 
are rotated concurrently and at the same speed, the cutting element 14 is 
moved vertically toward or away from the bed assembly 12, which in turn 
results in the movement of the cutting element 14 along the Y-axis as 
depicted in FIG. 2B above. Rotational drive of shafts 27 is accomplished 
by a separate drive motor 33 for each shaft 27 operating through a right 
angle drive means 34. Control of the motors 33 may be accomplished through 
any appropriate control means as discussed above relative to motor 21, as 
well as by a camming control arrangement described hereinafter. 
Each end of the cutting means assembly 13 is pivotally connected to its 
respective shelf or ledge assembly 32a or 32b by pins extending through 
aligned holes in ears or tabs 37 appropriately extending from shelf 
assemblies 32a and 32b and end plates 35 and 36 so as to permit relative 
pivotal movement between the end plates 35, 36 and shelves 32a and 32b 
about an axis defined by line 37a in FIG. 7. 
By virtue of these pivotal connections and a separate motor 33 for each of 
the screw shafts 37, the cutting element 14 may be angulated relative to 
bed 12 about Angle-a (or adjustments around the X-axis) as depicted above 
in FIG. 2C by the selective or differential operation of the two motors 
33. In other words, the end of cutting means assembly 13 adjacent one of 
the vertical column members 19 may be raised or lowered relative to the 
other end of cutting means assembly 13, and hence cutting element 14, to 
provide such angulated adjustment. Additionally, it is to be recognized 
that concurrent movement or adjustment of the cutting element 14 relative 
to bed 12 in both the Y-axis and about Angle-a can be accomplished by the 
simultaneous operation of both motors 33 in either opposite directions or 
in the same direction but at different speeds. 
The shelf assembly 32a, to which one end of cutting means assembly 13 is 
mounted, includes a keyed slide joint 38, as best seen in FIGS. 1 and 7, 
which permits compensation or adjustment for the hypotenuse dimensional 
changes between shelf members 32a and 32b as variable vertical 
relationships take place between both shelf members 32a and 32b and the 
surface of bed 12, as Angle-a adjustments or movements are made. 
For description of the structural arrangement to permit adjustment or 
movement of cutting element 14 relative to bed 12 about Angle-b (angular 
movement around the Y-axis) as depicted above in FIG. 2D, reference is now 
made to FIGS. 1, 3, 4 and 6. 
The shelf or ledge assembly 32a comprises a pair of lower plate members 39 
and 40 mounted on a pair of cantilever support arms 41: the plate members 
39 and 40 being keyed together to form the keyed slide joint 38 discussed 
above. Secured to plate 40 is a right-angled intermediate plate member 42 
having a slide pad member 43 mounted on the upper surface thereof. An 
upper plate member 44 is located such that its bottom surface is in 
slideable engagement with the upper surface of slide pad 43 (it being 
noted it is specifically the upper plate member 44 to which the ears or 
tabs 37 discussed above are mounted on and extend upwardly therefrom). 
Upper plate 44 is retained in sliding engagement with pad 43 by a 
plurality of guide rollers 45, 46, 47, 48 and 49 that are rotationally 
mounted on the upper surface of plate 42 in such manner that the 
rotational shoulders of rollers 45 and 46 ride in a right angle cut-out 50 
extending along one edge of plate 44 and the rotational shoulders of 
rollers 47, 48 and 49 ride in a right angle cut-out 51 extending along the 
opposite edge of plate 44; the right angle cut-outs 50 and 51 being 
slightly arcuate in a longitudinal sense as explained in more detail 
hereinafter. 
An additional pair of guide rollers 52 and 53 are rotationally mounted on 
plate 42; the rollers 52 and 53 having a medial step circumferentially 
therearound to ride in a slide or groove 54 extending lengthwise in a 
longitudinally extending rack member 55. Rach 55 is horizontally retained 
into rolling engagement with rollers 52 and 53 by a pinion 56 extending 
from a motor 57 and gear box 58 mounted to plate member 42 as best seen in 
FIG. 3; and concurrently, rack 55 is held in vertical alignment with 
rollers 52 and 53 and pinion 56 by the circumferential step on rollers 52 
and 53 riding in channel 54 of rack 55. 
A crank member 59, having a pin member 60 depending therefrom, is securely 
connected to rack 55 and extends outwardly therefrom with pin 60 riding in 
a slot 61 in a crank member 62 mounted to upper plate 44 and extending 
therefrom; the purpose of this interconnection being explained in more 
detail hereinafter. 
The interconnection between cutting means assembly 13 and shelf assembly 
32b, (as best seen in FIG. 4), structurally consists of a lower plate 
member 63 securely mounted to support arms 64 of shelf assembly 32b with a 
slide pad 65 securely fastened to plate 63 with an upper plate 66 (to 
which the pivot ears or tabs 37 are mounted for pivotal connection cutting 
means assembly 13 as described above). The plates 63 and 66 are pivotally 
assembled relative to each other by a bolt or pin 67 to permit relative 
rotation between plates 63 and 66 about a vertical axis defined by line 
68. 
In operation, adjustment or movement of cutting element 14 relative to bed 
12 about Angle-b (movement around the Y-axis) as shown above in FIG. 2D is 
accomplished by rotation of pinion 56 in one direction or the other, which 
in turn causes rack 55 to move in a respective direction longitudinally 
and rolling contact with the rollers 52 and 53 on plate 42. This movement 
of rack 55 in turn moves plate 44 relative to plate 42 by virtue of the 
pinned connection between crank members 59 and 62 and thereby causes the 
end of cutting means assembly 13 connected to shelf assembly 32a to move 
arcuately relative to the end of cutting means assembly 13 pivotally 
connected to shelf assembly 32b by pin 67 as described above. In view of 
this type of connection, it can be readily seen that the radius of the 
right angle cut-outs 50 and 51 on plate 44 will correspond to the linear 
distance between the respective cut-out and the axis 68 of pin 67. Also, 
it can be easily and readily understood by reference to FIG. 6 that for a 
minor sliding movement of plate 44 relative to 42, plate 44 is held or 
retained by all five of the guide rollers 45, 46, 47, 48 and 49, whereas 
movement of plate 44 to larger degrees or extent of adjustment relative to 
plate 42 results in plate 44 being retained or held by at least three of 
the guide rollers in a three point triangular type contact: i.e., as plate 
44 is moved upwardly and leftwardly as seen in FIG. 6, plate 44 is held 
and retained in its position through the contact with guide rollers 45, 47 
and 48, and that when plate 44 is moved rightwardly and downwardly as seen 
in FIG. 6, the plate 44 is held and retained through the contact with 
guide rollers 46, 48 and 49. 
The fifth or final type of adjustment for cutting element 14 relative to 
bed 12 (as shown in FIG. 2E) is the tilt or adjustment of cutting means 
assembly 13 about a vertical plane defined by the vertical column members 
19 of gantry assembly 11 through the interconnection of cutting means 
assembly 13 to end plates 35 and 36 now to be described with reference to 
FIGS. 1, 3, 4 and 7. Cutting means assembly 13 is provided with an 
appropriate plate member 69 at each upper end thereof, to which are 
mounted a plurality of roller means 70 and 71 for rolling engagement or 
contact with the respective end plates 35 and 36. Rollers 70 are arranged 
in pairs and gapped substantially the thickness of end plates 35 and 36 so 
that one roller of each pair of rollers 70 is in rolling contact with the 
opposite sides of their respective end plate 35 or 36. Rollers 71 are 
mounted about a horizontal axis for rolling engagement with appropriate 
surfaces of arcuate cam members 72 and mounted respectively on the sides 
of both end plates 35 and 36 confronting the cutting means assembly 13. 
The cutting means assembly 13 is also pivotally connected to each end 
plate 35 and 36 by a pin or bolt 73 at the lower portions of end plates 35 
and 36. The center line of the bolts or pins 73 are placed in alignment to 
form an axis 74 about which cutting means assembly 13 can pivot relative 
to both end plates 35 and 36. 
This pivoting of cutting means assembly 13 relative to end plates 35 and 36 
is (which constitutes an Angle-c movement or adjustment about the Z-axis) 
accomplished by a pinion 75 engaging an arcuate rack segment 76 securely 
mounted on end plate 35; the pinion 75 being driven by a motor 77 through 
a reduction gear box 78 that are mounted on the cutting means assembly 13. 
The various adjustments or movements of the cutting means assembly 13 to 
permit the adjustments or movements of the cutting element 14 relative to 
bed 12 as described above is mechanically attainable by the expediency of 
locating the axes 37a and 74 associated with shelf assembly 32a so that 
they intersect at right angles with each other, and likewise locating axes 
37a, 68 and 74 associated with shelf assembly 32b so that they all 
intersect with each other at right angles as best seen in FIGS. 4 and 7. 
Additionally, it is believed most efficient and economical for calculating 
the various adjustment control signals and interrelationships if the 
cutting point line in the case of a flat band saw and the center of round, 
continuous cutting members or hot wires are located coextensively with the 
pivotal axis 74 described above for the Angle-c movement about the Z-axis. 
As stated above, the cutting element 14 may be a continuous band saw blade 
of flat or round cross-sectional shape or a hot wire or other type of 
longitudinal, straight-line cutting element. When cutting element 14 is a 
continuous band saw mounted on cutting means assembly 13, its drive is 
powered by a motor 79 also mounted on cutting means assembly 13: it being 
recognized that in the case of a hot wire cutting element, appropriate 
controls and sources of heat for delivery to the hot wire cutting element 
will be substituted for the motor 79. Also, the precise drive or control 
mechanism for powering cutting element 14 may be any of the prior art 
arrangements and form no part of this invention. 
While all of the various movement of adjustment motors 33, 57 and 77 
described above may be powered in the same manner as motor 21 such as by 
manual control, numerical control tapes, computer controlled electronic 
circuits, etc., it can also be recognized that movements or adjustments of 
the types shown in FIGS. 2B through 2E may be accomplished by a cam 
control arrangement as shown in FIGS. 1, 3 and 5. As shown, an appropriate 
mechanically configured cam plate 80 may be securely mounted along side 
the edge of bed assembly 12 to present a camming surface 81 for contact by 
an appropriate vertical sensing means 82, readily available from the prior 
art for control of either or both motors 33. Also, additional camming or 
trip members 82 may be mounted on cam plate 81 for tripping or controlling 
micro-switches 83 as shown in FIG. 5, which in turn can operate on control 
motors 57 or 77 selectively; it being recognized that although not shown, 
the micro-switches or control members 83 are connected in an appropriate 
manner to gantry assembly 11 as is camming sensing means 82. Likewise, it 
is also to be understood that before any cam control or operation of 
motors 33, 57 or 77 takes place, motor 21 must be energized for relative 
motion between gantry assembly 11 and bed assembly 12. Also, while FIG. 1 
shows cam plate 80 mounted to one side of bed 12 only, it is to be 
appreciated that a corresponding cam plate 80 may be mounted on the other 
side of bed 12; the presence of a cam plate 80 on both sides of bed 12 or 
only one side thereof being dependent upon the type of camming control 
desired for the installation involved. 
In operation, a compound curvature surface may be formed on a workpiece 
mounted upon the bed 12 in any appropriate manner or by any appropriate 
means from the prior art (the workpiece and mounting details not being 
shown as they do not form a part of this invention), and thereafter moving 
the cutting element 14 longitudinally relative to the bed assembly 12 as 
shown in FIG. 2A through the supply of power to motor 21. As such 
longitudinal travel or movement along the X-axis as shown in FIG. 2A takes 
place, a compound surface can be generated in the workpiece by appropriate 
movement or adjustment of the cutting element 14 relative to the bed 12 
through the selective energization of one or both motors 33, motor 57 or 
motor 77 in a selective and predetermined basis so that cutting element 14 
is moved relative to the bed assembly 12 in any one or combination thereof 
of the X-axis, Angle-a, Angle-b and Angle-c movements depicted in FIGS. 
2B, C, D and E. 
While particular embodiments of the invention have been illustrated and 
described, it will be obvious to those skilled in the art that various 
changes and modifications may be made without departing from the 
invention, and it is intended to cover in the appended claims all such 
modifications and equivalents that fall within the true spirit and scope 
of this invention.