U.S. patent number 3,884,462 [Application Number 05/428,201] was granted by the patent office on 1975-05-20 for mobile geometrical form.
Invention is credited to Francis Rebajes.
United States Patent |
3,884,462 |
Rebajes |
May 20, 1975 |
Mobile geometrical form
Abstract
A mobile geometrical form in the general shape of a hyperbolic
paraboloid is described as made from a continuous strip of material
to form a continuously twisted shape having both an external edge
and an internal edge. The internal edge of the form defines an
opening centrally in the form. The form has two distinct continuous
surfaces on opposing sides of the strip from which the form is
made. Each side or surface has four lines of inflection to result
in four surface portions having successive concave and convex
contours. Opposing surface portions of the strip between the same
inflection lines have opposing concave and convex contours. The
form is made of a semi-rigid flexible material such as sheet metal.
In this manner, the strip can assume the predetermined geometrical
form in an infinite number of relative positions of the strip. The
stresses established in the strip redistribute themselves in each
relative position of the strip as the latter translates along a
path generally defined by the form itself to maintain the shape of
the same.
Inventors: |
Rebajes; Francis
(Torremolinos-Malaga, ES) |
Family
ID: |
23697950 |
Appl.
No.: |
05/428,201 |
Filed: |
December 26, 1973 |
Current U.S.
Class: |
472/57; 273/155;
428/12; 428/542.2; 434/403; 482/44; 428/28; 434/211; 446/85;
D21/468 |
Current CPC
Class: |
B44C
3/00 (20130101) |
Current International
Class: |
B44C
3/00 (20060101); D04d 009/04 () |
Field of
Search: |
;161/7 ;D34/15A ;35/73
;46/23,24 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Schulz; William E.
Attorney, Agent or Firm: Friedman & Goodman
Claims
What is claimed is:
1. A mobile geometrical form comprising a double-sided continuous
strip of material, each side having four points of inflection to
thereby result in four surface portions having successive concave
and convex contours, opposing surface portions of said strip
between the same inflection points having opposing concave and
convex contours.
2. A mobile geometrical form as defined in claim 1, wherein said
strip of material is made of a semi-rigid flexible material, said
strip assuming the geometrical form in an infinite number of
relative positions of said strip, the stresses established in said
strip redistributing themselves in each relative position of said
strip to maintain the shape of the geometrical form.
3. A mobile geometrical form as defined in claim 2, wherein said
material is a sheet of metal.
4. A mobile geometrical form as defined in claim 2, wherein said
material is a sheet of elastomeric plastic.
5. A mobile geometrical form comprising a double-sided continuous
strip of material, said strip being twisted to cause each surface
to include two portions thereof which substantially face each other
and two portions which are substantially directed away from one
another, said portions facing each other and said portions directed
in opposing directions being symmetrically disposed about and
substantially parallel to respective planes which are normal to one
another.
6. A mobile geometrical form as defined in claim 5, wherein said
strip of material is made of a semi-rigid flexible material, said
strip assuming the geometrical form in an infinite number of
relative positions of said strip, the stresses established in said
strip redistributing themselves in each relative position of said
strip to maintain the shape of the geometrical form.
7. A mobile geometrical form as defined in claim 6, wherein said
material is a sheet of metal.
8. A mobile geometrical form as defined in claim 6, wherein said
material is a sheet of elastomeric plastic.
9. A mobile geometrical form in the general shape of a hyperbolic
paraboloid, said form comprising a continuous strip of material to
thereby form both an external edge and an internal edge, said
internal edge forming an opening centrally of said form.
10. A mobile geometrical form as defined in claim 9, wherein said
internal edge is smooth.
11. A mobile geometrical form as defined in claim 9, wherein said
internal edge is smooth and includes at least one extension
extending in a direction generally centrally of the form.
12. A mobile geometrical form as defined in claim 11, wherein a
plurality of extensions are provided along the length of said
internal edge each extending in a direction generally centrally of
the form.
13. A mobile geometrical form as defined in claim 12, wherein said
extensions are triangular.
14. A mobile geometrical form as defined in claim 9, wherein said
external edge is smooth.
15. A mobile geometrical form as defined in claim 9, wherein said
external edge is smooth and includes at least one extension
extending generally away from the central region of the form.
16. A mobile geometrical form as defined in claim 15, wherein a
plurality of extensions are provided each extending in a direction
generally away from the central region of the form.
17. A mobile geometrical form as defined in claim 16, wherein said
strip is made of a semi-rigid flexible material, said strip
assuming the geometrical form in an infinite relative positions of
said strip, the stresses established in said strip redistributing
themselves in each relative position of said strip to maintain the
shape of the geometrical form.
18. A mobile geometrical form as defined in claim 17, wherein said
external edge has a predetermined length, and wherein two
extensions are provided at points along said predetermined length
to form therebetween two equal length portions.
19. A mobile geometrical form as defined in claim 18, wherein each
extension extends in a direction substantially normal to the
external edge portion from which it projects, each extension being
provided with a surface at the free end thereof which is
substantially parallel to the respective external edge portion, the
form being supportable on said end surfaces when said extensions
are disposed adjacently to one another in opposing relation.
20. A mobile geometrical form as defined in claim 18, wherein one
of said extensions is fixed in space relative to the other
extension, the other extension being movable between two positions,
one position wherein said extensions are disposed in adjacent
substantially parallel and opposing positions, and another position
wherein the surfaces of said extensions which face each other in
said one of said positions facing away from each in the other of
said positions.
21. A mobile geometrical shape formed by two concentric annular
strips each having first and second opposite surfaces respectively
facing the same direction and each having adjacent first and second
opposing edges, with respective first and second edges of each of
said strips being disposed adjacently to each other, and a first
edge of one strip being connected to a second edge of the other
strip to result in a spiral wherein said first surfaces and second
surfaces of each said strips respectively merge, one of the free
ends of said strips being bent to bring portions of one of said
surfaces into a facing condition, said one of the free ends being
brought adjacently to the other free end and said free ends being
twisted and joined to cause said first and second surfaces to
respectively merge, whereby both said first and second surfaces
become continuous when all said opposing edges have been
joined.
22. A method of forming a mobile geometrical shape comprising the
steps of
A. disposing two slotted annular strips concentrically to each
other, each of said strips having first and second opposing
surfaces respectively facing the same directions and first and
second opposing edges;
B. connecting a first edge of one strip with a second edge of the
other strip to cause said first and second surfaces to merge at the
point of connection, the resulting shape being a spiral having said
first surfaces generally facing one direction and said second
surfaces generally facing an opposing direction;
C. bending one free end of the resulting spiral to cause portions
of one of said surfaces to face each other;
D. bringing said edges at the free ends of the spiral into
proximity to each other;
E. aligning the free ends and opposing edges to bring corresponding
first and second surfaces at the free ends to positions generally
facing the same direction; and
F. joining said free ends to each other, whereby said first and
second surfaces each form a continuous loop when all the opposing
edges have been connected.
Description
BACKGROUND OF THE INVENTION
Various geometrical forms are known. Some of these forms are found
in the fields of structural architecture, abstract art, complex
machine parts including cams and followers and home display or
decorative objects. However, the present invention discloses a
novel geometrical form which has unique characteristics which makes
the same suitable for being adapted for many varied uses.
The mobile geometrical form of the present invention, which is in
the general shape of a hyperbolic paraboloid, is made of a
semi-rigid flexible material. Once the form is established, in
accordance with the method to be described, the strip assumes the
novel geometrical form in an infinite number of relative positions
of the strip. Translatory motion of the strip, within a general
path outlined by the form, redistributes the stresses established
in the strip in each position of the latter to maintain the shape
of the geometrical form. The forces required to translate the strip
within its general outline or shape are a function of the
flexibility of the material from which it is made and can be
reduced to minimal values.
Accordingly, the novel and aesthetically pleasing form of the
present invention can be utilized both for ornamental purposes as
well as other mechanical utilitarian purposes. For example, the
form is particularly suitable as a reciprocating movement or motion
device. Also, the novel form can be utilized to convert linear into
curvilinear movements or vice versa. Other important uses of the
device include amusement and exercise. For example, as will become
evident from the description that follows, the form can be
continuously or reciprocally advanced while continuously
maintaining a fixed grip on two points of the form. This suggests
possible use in physical therapy applications to provide exercise
to muscles in the arms and wrists.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a
novel geometrical form which exhibits new and unusual properties
not known heretofore in prior art geometrical forms.
It is another object of the present invention to provide a novel
and useful geometrical form which is simple in construction and
economical to manufacture.
It is still another object of the present invention to provide a
novel geometrical form which is made of a continuous strip of
semi-rigid flexible material and which can be either continuously
or reciprocally translated along a path generally defined by the
novel shape.
It is yet another object of the present invention to provide a
mobile geometrical form which is in the general shape of a
hyperbolic paraboloid but having an internal edge forming an
opening centrally of the form and which is made of a continuous
strip of material.
It is a further object of the present invention to provide a mobile
geometrical form of the type above suggested which can be utilized
for ornamental as well as mechanically utilitarian purposes.
It is still a further object of the present invention to provide a
mobile geometrical form of the type generally under discussion
which can translate linear into curvilinear motion and vice
versa.
It is yet a further object of the present invention to provide a
mobile geometrical form as suggested in the above objects which can
be utilized both for amusement and exercise purposes.
It is an additional object of the present invention to provide a
method for easily assembling and forming the mobile geometrical
form above described.
In order to achieve the above objects, as well as others which will
become apparent hereafter, a mobile geometrical form in accordance
with the present invention comprises a double-sided continuous
strip of material, each side having four points of inflection to
thereby result in four surface portions having excessive concave
and convex contours. Opposing surface portions of said strip
between the same inflection points have opposing concave and convex
contours. The double-sided continuous strip of material is twisted
to cause each surface to include two portions thereof which
substantially face each other and two portions which are
substantially directed away from one another, the portions facing
each other and the portions directed in opposing directions being
symmetrically disposed about and substantially parallel to
respective planes which are normal to one another. Generally, the
novel mobile geometrical form of the present invention is in the
form of a hyperbolic paraboloid which, when formed from a
continuous strip of material, exhibits both an external edge and in
internal edge, with the internal edge forming an opening centrally
of the form.
Advantageously, the strip of material is made from a semi-rigid
flexible material. In this manner, the strip assumes the
geometrical form in an infinite number of relative positions of the
strip. The stresses established in the strip redistribute
themselves in each relative position of the strip to maintain the
shape of the geometrical form.
According to some presently preferred embodiments, the external and
internal edges of the form are smooth. However, protuberances in
the form of projections may be provided on the internal, external
or both edges. With such protuberances, the mobile geometrical form
adds extra dimensions for possible uses to which it can be applied.
As suggested above, such a geometrical form can be utilized for
ornamental, amusement, exercising, and mechanical uses.
BRIEF DESCRIPTION OF THE DRAWINGS
With the above and additional objects and advantages in view, as
will hereinafter appear, this invention comprises the devices,
combinations and arrangements of parts hereinafter described and
illustrated in the accompanying drawings of a preferred embodiment
in which:
FIGS. 1 and 2 are top plan views of slitted annular strips from
which the mobile geometrical form in accordance with the present
invention may be formed;
FIG. 3 is a side elevational view of the two annular strips shown
in FIG. 1 when the strips are concentrically disposed and opposing
edges are joined to permit the connected annular strips or
resultant strip to be stretched along the general direction of the
axis into the general shape of a helicoid;
FIG. 4 is a perspective view of the helicoid shown in FIG. 3,
showing the manner in which the helicoid is formed by separation of
the free ends of the respective annular strips;
FIG. 5 is a front elevational view of the connected strips after
one of the free ends of the resultant strip is bent to bring
portions of one of the resulting surfaces of the helicoid onto
itself whereby portions of a single surface face each other;
FIG. 6 is similar to FIG. 5, showing the condition when one of the
free ends has been brought adjacently to the other free end and
wherein the free ends are aligned to bring the corresponding
surfaces at the free ends to positions generally facing the same
direction;
FIG. 7 is similar to FIG. 6, showing the condition when the free
ends are joined to each other to thereby cause each of the original
helicoid surfaces to form a continuous surface once all the
opposing edges have been connected;
FIG. 8 is a front elevational view of the novel geometrical form
resulting from the above suggested and illustrated construction,
the form being generally in the shape of a hyperbolic paraboloid
which defines an external edge and an internal edge, with the
internal edge forming an opening centrally of the form;
FIGS. 9 and 10 are perspective views of the geometrical form shown
in FIG. 8, taken from different angles to clearly illutrate the
novel form;
FIGS. 11-16 are front elevational views similar to FIG. 8, each
view showing two points at slightly translated positions, the
FIGURES showing the manner in which the form of the present
invention permits, when made of a semi-rigid flexible material,
translation or movement of the strip along a path generally defined
by the extent of the latter. The strip may thus assume an infinite
number of relative positions with the stresses established in the
strip redistributing themselves in each relative position to
maintain the shape of the geometrical form. While FIGS. 11-16
illustrate translatory movement of the strip to thereby result in
all points on the strip moving, it is also possible to fix one
point on the strip. When one point on the strip is fixed, movement
of the type suggested in FIGS. 11-16 causes the geometrical form to
reciprocate from side to side about the fixed point while including
curvilinear nutating-type movement;
FIGS. 17 and 18 are similar to FIGS. 1 and 2, but showing a
plurality of projections along the length of the internal edge
extending in the direction generally centrally of the annular
discs; and
FIG. 19 is a perspective view of a second embodiment of a mobile
geometrical form in accordance with the present invention made from
the discs shown in FIGS. 17 and 18.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the FIGURES, in which identical or similar parts
have been designated by the same reference numerals throughout, and
first referring to FIGS. 1 and 2, the mobile geometrical form in
accordance with the present invention will be described as being
formed of two slitted annular strips 10 and 30. While the
description will be outlined in the order in which the strips are
assembled to ultimately form the novel form or shape, it is pointed
out that the same or similar form need not be formed from two
individual strips but may be molded or constructed from a single
continuous strip.
The annular strip 10 includes a disc 12 having an upper surface 14
and a lower surface 16, as viewed in FIG. 1. The disc 12 is
provided with a slit 18 to form an end portion 20, marked with an
A, and an opposing end portion 22, marked with a B.
Similarly, the annular strip 30 includes a disc 32 having an upper
surface 34 and a lower surface 36, as viewed in FIG. 2. The disc 32
is provided with a slit 38 to thereby form opposing end portions 40
and 42, respectively designated by the letters B and A.
The annular strip 10 is provided with a central opening 24. In the
presently preferred embodiment, the central opening 24 is defined
by a smooth internal edge 26. The external periphery or edge
contour is defined by a smooth edge 28. To facilitate the
description of the novel geometrical form and the principle which
makes it possible, the internal and external edges 26 are shown as
simple concentric circular edges. Modifications of the internal and
external edges will be more fully described in connection with
FIGS. 17-19.
Similarly, the annular strip 30 is provided with a central opening
44 defined by a circular smooth internal edge 46. The external
circular edge 48 is concentric with the internal edge 46 and is
similarly smooth.
The upper sides or surfaces 14 and 34, as well as the lower
surfaces 16 and 36 are so defined for facilitating the description
of the invention. These surfaces have no other significance and,
clearly, inversion of the discs would reverse the roles of the
described surfaces.
With the annular strips disposed as shown in FIGS. 1 and 2, it is
pointed out that the end portion 20, shown to the left of the slit
18 in FIG. 1, is designated by the letter A. On the other hand, the
end portion 40, to the left of the slit 38, is designated by the
letter B. Similarly, the end portions 22 and 42, respectively to
the right of slits 18 and 38, are respectively marked by the
letters B and A.
The first step in assembling the annular strips 10 and 30 is to
dispose the strips one on top of the other in a concentric fashion
whereby the discs 12 and 32 overlap with the slits 18 and 38
aligned. In this condition, the end portion 20 is disposed
contiguous to the end portion 40 while the end portion 22 is
contiguous to the end portion 42. An end portion to the right of
the slit of one of the strips is now joined to an end portion to
the left of a respective slit on the other strip. Thus, either the
end portion 20 may be joined to the end portion 42 or the end
portion 22 may be joined to the end portion 40. The particular set
of end portions which are connected in this manner is not critical
and the same ultimate results are obtained, as will become evident
hereafter. As suggested in FIGS. 3 and 4, the end portions 20 and
42 have been joined in the example presently being described. The
joint 50 may be formed by connecting the end portions 20 and 42 in
any conventional means, such as with screws and wing nuts 52.
The resulting form is generally described as a right helicoid when
the remaining free end portions 22 and 40 are separated from each
other or the resulting strip is stretched generally along the axis
of symmetry.
In FIG. 4, the resulting helicoid is shown when the end portions 22
and 40 are moved in opposing directions. It should be noted that
the effect of joining the two annular strips 10 and 30 in this
fashion causes the upper surfaces 14 and 34 to merge and define a
continuous helical surface. Similarly, the lower surfaces 16 and 36
of the respective annular strips 10 and 30 similarly merge to form
a helical surface. Thus, the upper surfaces 14 and 34 generally
face a single direction along the axis of the resulting helicoid
while the lower surfaces 16 and 36 similarly face a single opposing
direction along the axis.
Also shown in FIG. 4 are cutout portions 54 at the end portion 22
while bolts 56 are shown projecting from the end portion 40 which
are adapted to be received within the cutout portions 54 when the
free ends of the helicoid are joined in a manner to be described
hereafter.
As suggested above, the annular strips 10 and 30 are made of a
semi-rigid flexible material. This material may either be sheet
metal or a sheet of elastomeric plastic material. The thickness and
hardness of the annular strips will determine the ease with which
the resulting geometrical form can be shifted or translated along
itself, as will become evident hereafter.
Referring to FIG. 5, the next step in the assembly of the
construction of the form is the bending of one free end of the
resulting spiral or helicoid shown in FIG. 3 to cause, in the
example shown in FIG. 5, lower surface portions 16' and 36' to face
each other. The configuration shown in FIG. 5 is achieved by
bending the disc 32 at the end portion 40 inwardly or towards the
end portions 20 and 42 and bringing the lower surface 36 in the
region of the end portion 40 to a facing condition with respect to
the lower surface 16 of the disc 12. Once the disc 32 has been so
deformed, the end portion 40 is continuously moved along the lower
surface 16 in a generally counter-clockwise direction, as viewed in
FIG. 4, until the end portion 40 is disposed adjacent to the end
portion 22.
The transformation between the shapes shown in FIGS. 5 and 6 are
effected by twisting the resulting end portions 22 and 40 towards
each other to dispose the lower surface portions 16' and 36' in a
common plane. The free ends and end portions 22 and 40 are then
aligned to dispose the edges at the free end portions coextensively
with one another and cause the upper surfaces 14 and 34 and lower
surfaces 16 and 36 at the free end portions to generally face the
same directions.
The final step of the construction process is the joining of the
free ends to each other at a second joint 58, shown in FIG. 7. The
resulting mobile shape or form is generally designated by the
reference numeral 60. It will be noted that the form 60 merges the
original upper surfaces 14 and 34 into a continuous surface.
Similarly, the original lower surfaces 16 and 36 of the component
annular strips are similarly merged into a continuous surface.
It is also noted that the novel mobile form 60 now includes an
internal edge 62 which represents the original internal edges 26
and 46 which merge when the annular strips are joined as described.
Similarly, a new continuous external edge 64 is defined by the form
60 which replaces the original external edges 28 and 48 of the two
component strips. The above described continuous edges and surfaces
are shown in FIGS. 7 and 9.
The novel mobile shape or form 60 defines an interesting
mathematical warped surface resembling, in certain respects, the
doubly ruled hyperbolic paraboloid. However, it should be noted
that the hyperbolic paraboloid is formed of a solid warped or
deformed planar sheet. On the other hand, the form 60 of the
present invention is in the form of a continuous warped strip
having a finite width. For this reason, an internal edge 62 is
defined which forms a central opening exhibited by the form 60. It
is the provision of the internal edge 62, and the central opening
which it represents, which substantially increases the versatility
of the form 60 since this permits the translatory and reciprocating
movements which have been suggested above and which will be further
described hereafter in connection with FIGS. 11-16.
An interesting characteristic of the novel form 60 is its ability
to maintain the shape shown in the FIGURES even though the form may
be made from a semi-rigid flexible material. The tendency for the
form 60 to maintain its shape exists even when limited external
forces are applied to the form. In this connection, reference is
had to FIGS. 8 and 10 wherein the mobile form 60 is viewed at a
particular instance of time. In the configuration shown, the form
60 exhibits four lines of inflection 66. These lines are inflection
separate or divide each of the surfaces, i.e., the original merged
lower surfaces or the original merged upper surfaces, into four
surface portions each having successive concave and convex
contours. Clearly, opposing surface portions of the resulting strip
between the same inflection lines have opposing concave and convex
contours. The concave surfaces or contours are designated by the
reference numeral 68 while the convex surfaces or contours are
designated by the reference numeral 70. In this connection, the
form 60 can be described as a continuous strip of material which is
twisted in such a manner to cause each continuous looped surface to
include two portions thereof which substantially face each other
and two portions which are substantially directed away from one
another. The portions which face each other and the portions
directed in opposing directions being symmetrically disposed about
and substantially parallel to respective planes which are normal to
one another. In the example illustrated in FIG. 10, the surface
portions which face each other are always the convex surfaces 70
while the surface portions which are directed away from each other
are always the concave surfaces.
The lines of inflection 66 which are exhibited in the form 60 are
caused by and represent a distribution of stresses within the
resulting continuous strip which tends to maintain the strip in the
shape shown in FIGS. 8-16. However, referring to FIGS. 11-16, it
will become clear that the strip may assume the same geometrical
form in an infinite number of relative positions of the strip. In
each case, the stresses established in the strip redistribute
themselves in each relative position of the strip to maintain its
shape of the geometrical form 60. In this sense, the restoring
forces at any single point on the continuous loop tend to revert
that portion into the planes of the original flat annular strips 10
and 30. It is these restoring forces which maintain the curved or
warped condition of the form 60 in a state of equilibrium or
stability.
The mobility or ability of the form 60 to move or translate along
itself is based on the semi-rigid characteristic of the resulting
strip, the central opening defined by the internal edge 62 and the
ability of the resulting shape to reach a stable equilibrium and
distribution of stresses which tend to maintain the strip in the
desired shape or form. Referring to FIGS. 11-16, the resulting form
60 is shown in each FIGURE with markings 72 and 74. The markings 72
and 74 are provided on the strip to indicate fixed points on the
strip to illustrate the translatory movement of which the present
form 60 is capable of achieving. To best understand this type of
movement, it may be helpful to imagine an imaginary continuous path
or corridor which is flat and shaped to receive internally thereof
the form 60. If such a shaped path or guide corridor could be
imagined, the translatory motion which is illustrated in FIGS.
11-16 is comparable to the constant advancement of each point on
the continuous strip of the form within the imaginary guide path or
corridor. Stated otherwise, the movement illustrated in the FIGURES
is such that each fixed point on the resulting form 60 can
continuously move along a path generally defined by the form
itself. Thus, the point 72 is shown in the lower left corner in
FIGURE 11 while the marking 74 is in the upper right corner.
However, with sliding or translatory motion of the entire strip in
the direction indicated by the dashed arrows, the point or marking
72 is advanced towards the middle left while the marking 74 is
moved towards the middle right of the form. With continued movement
of the resulting strip in the direction of the dashed arrows, the
points 72 and 74 ultimately move to the rear of the form in FIG. 14
and continue to advance to positions shown in FIG. 16. A FIGURE
subsequent to FIG. 16 would appear similar to FIG. 11 wherein the
point A has moved from the rear onto the upper right corner of the
form and the marking 74 from the rear to the lower left corner of
the form as shown in FIG. 11. It is pointed out in connection with
FIGS. 11-16 that the translatory motion there shown results when
every point of the form is moved relative to a fixed point
externally of the form. It is for this reason that the strip is
permitted to advance while the overall form appears to be
statioary, with the exception to the reference to markings 72 and
74.
A substantially different effect is observed when the translatory
motion above described is applied to a form 60 which is fixed at
one point thereof. When this is done, the form exhibits the above
translatory motion, but additionally reciprocates from side to side
about the fixed point in a cyclical motion not unlike a nutating
motion.
Uses of the form 60 are numerous. In addition to ornamental,
artistic and amusement devices or objects, the present invention
exhibits properties which are useful in mechanical arrangements.
The translatory motion described in connection with FIGS. 11-16 may
be utilized in a camming action. With one point fixed, a
reciprocating motion can be achieved which exhibits both linear as
well as curvilinear components. As described above, the fixing of
one point causes the form 60 to reciprocate from side to side about
the fixed point, this being a useful feature in some forms of
machines. In this connection, the reciprocatory motion may be
mechanized by alternating applying opposing forces to the
continuous strip proximate or adjacent to the fixed point. The
frequency of reciprocation then corresponds to the frequency at
which the opposing forces are applied to the portions of the strip
adjacent to the fixed point.
While the above described forms exhibit smooth internal and
external edges, it is pointed out that projections of various
shapes can be provided along these edges. Referring to FIGS. 17 and
18, discs 76 and 77 are shown which are similar to the discs 12 and
32 shown in FIGS. 1 and 2. The discs 76 and 77 are each provided
with slits 78 and opposing end portions 80 and 82. Each of the
discs is provided with a plurality of equally angularly spaced
radial slits 84 which together define central openings or holes 86.
In order to prevent the overlap of two triangular projections when
the discs are assembled, a space 88 is provided on each disc which
permits the overlapping of the end portions 80 and 82 without
resulting in an overlap of triangular projections or
extensions.
The procedure for assembling the discs 76 and 77 is identical to
that described in connection with discs 12 and 32. The resulting
form is designated by the reference numeral 60' shown in FIG. 19.
Clearly, the forms are very similar, with the exception that the
form 60' includes a plurality of triangular projections which
project centrally into the form. The ends or tips of each of the
projections together define a square-like opening 90. The mobile
property of the form 60' are similar to those described in
connection with the form 60.
Likewise, while the external edge 64 of the form 60 has been shown
and described as being smooth, suitable protuberances or
projections may similarly be provided along the external edge 64.
Such projections generally extend in a direction away from the
central region of the form. According to one embodiment of the
present invention, the external edge 64 has a predetermined length.
In this embodiment, two extensions are provided at points along the
predetermined length to form therebetween two equal length
portions. Each extension extends in a direction substantially
normal to the external edge portion from which it projects and each
extension is provided with a surface at the free end thereof which
is substantially parallel to the respective external edge portion.
The form 60 is supportable on the two end surfaces when the
extensions, in the form of legs, are disposed adjacently to one
another in opposing relation. As suggested above, when one of these
extensions or legs is fixed in space relative to the other
extension, the other projection is movable between two positions.
In one position, the extensions are disposed in adjacent,
substantially parallel and opposing positions. In the other
position, the surfaces of the extensions, which faced each other in
the first or initial position, face away from each other in the
other or second position. By successively fixing each of the legs
or extensions, the form can be advanced along a linear
direction.
It will thus be noted from the above description that the novel
geometrical form of the present invention can exhibit various forms
of motion while it does not have any moving parts.
While reference has been made throughout to annular strips, it is
pointed out that this phrase is not intended to be limited to
circular annular strips, as suggested, for example, in FIGS. 1 and
2. The term annular strip in the context of the present description
and claims is intended to include any flat sheet of arbitrary
peripheral or edge contours or outlines. This may include square,
triangular or any shaped sheets. Each sheet, irrespective to its
outside contour or edge configuration is provided with an internal
opening, which may again assume an arbitrary shape. The internal
opening may be disposed anywhere within the external edge
boundaries, not necessarily centrally located. The slits above
described now extend between an internal and external edge
boundary.
Numerous alterations of the structure herein disclosed will suggest
themselves to those skilled in the art. However, it is to be
understood that the present disclosure relates to a preferred
embodiment of the invention which is for purposes of illustration
only and is not to be construed as a limitation of the
invention.
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