[0001] The device for moving tools along a circular trajectory is an item of apparatus which
allows the user to execute circumferences and arcs of circumferences with radii of
any length, including radii longer than the apparatus itself, without needing to place
a fixed point in the centre of the circle.
It is capable of making an arc of circumference with a radius of several metres on
a small sheet of paper (A4 for example) without the need for any support outside the
area of the paper. Used in conjunction with any kind of cutting equipment (a fret
saw for example) it makes it possible to cut a circle immediately, without the need
for a central attachment. Positioned for a radius of infinite length, it does away
with the need for a parallel guide, and can moreover continue in any direction.
[0002] It is made up fundamentally of three moveable points of support, two of which are
linked by an axis and the third of which consists of a moving ball which is pulled
in the direction of movement of the first two. This last serves to keep the device
stable, preventing large variations in the pressure exerted on the pencil or pen or,
in the case of cutting tools, keeping the blade at a constant height. The two connected
points of support take the form of two wheels which are knurled so as better to grip
the paper. Where electric cutting tools are to be used this knurling must be deeper,
to prevent the vibrations of the tool pushing the device off course.
[0003] It is essentially the following which makes it possible to trace an arc of circumference
of a certain radius:
1. The two wheels connected by an axis have different diameters, so that when they
roll they have a conical motion, acting like two planes of a frustum perpendicular
to the axis.
2. The wheels can be moved along the axis and fixed in place so that they are closer
together or further apart, in such a way as to modify the frustum that they define,
and thus change the radius of the curve that they describe.
3. There can be more than two wheels, with some attached to others, for example by
means of screws, with at least one in each set capable of being fixed to the axis
to prevent the set from rolling. Only the two wheels with the greatest diameter in
each set rest on the work surface, so that by moving one or more wheel from one set
towards another, and moving the sets closer or further apart by sliding one of them
along the scale, it is possible to obtain a continuous range of radii.
1. A device for moving tools along a circular trajectory, the defining characteristics
of which are an axis to which can be attached two wheels of different diameters, with
a body which allows it to roll in a circle when its two wheels rest on a level surface,
this body also having a third, spherical point of support which rolls in any direction
to enable the apparatus to remain in a stable position, and a bracket for a writing
implement (for example a pen) the position of which can be adjusted along the edge
of the body of the device by way of a first graduated scale, to allow circumferences
of different radii to be drawn, it also being possible to move the wheels attached
to the axis to different positions along a second scale marked on the axis, so as
to alter the range of radii that can be obtained by sliding the bracket for the writing
implement along the first scale.
2. A device, in accordance with the first claim, the defining characteristics of which
are several wheels of different diameters, arranged in two groups, which are capable
of being attached to the axis and to each other, such that the wheel of greatest diameter
in each group rests on the work surface, and by moving one or more from one group
to the other it is possible to vary the wheel which is in contact with the surface,
thus extending the range of radii that can be drawn.
3. A device for moving a tool along a circular trajectory, the defining characteristics
of which are an axis to which can be attached two wheels of different diameters, with
a body which allows it to roll in a circle when its two wheels rest on a level surface,
this body also having a third, spherical point of support which rolls in any direction
to enable the apparatus to remain in a stable position, and a bracket for a cutting
tool (for example an electric saw) the position of which can be adjusted along the
edge of the body of the device by way of a first graduated scale, to cut circles with
various radii, it also being possible to move the wheels attached to the axis to different
positions along a second scale marked on the axis, so as to alter the range of radii
that can be obtained by moving the cutting tool along the first scale.
4. A device, in accordance with the third claim, the defining characteristics of which
are several wheels of different diameters and two of equal diameter, arranged in two
groups, which are capable of being attached to the axis and to each other, such that
the wheel of greatest diameter in each group rests on the work surface, and by moving
one or more from one group to the other it is possible to vary the wheel which is
in contact with the surface, thus extending the range of radii that can be cut, and
such that, by placing the two wheels of equal radius each in its group, the device
can be set for a radius of infinite length, making it possible to cut in a straight
line in any direction.