Bunker Hill Community College
Science in Space Club
Dirigible Drone Prototype Test
Jonathan Sheetz, MD
Faculty Advisor
Brookside Campground
Catskill, NY
April 18, 2015
Inspiring Science Learning
Sunday, June 7, 2015
Friday, May 1, 2015
Monday, November 17, 2014
Hand-Powered Stone Saw [pending U.S. Patent]
United
States Patent Application
Sheetz
Application
Number
Date of
Application August 7, 2014
HAND-POWERED,
CENTRIFUGAL MASONRY SAW
Inventor: Sheetz, Jonathan Patrick
Applicant: Sheetz,
Jonathan Patrick
Address: 45 Tudor St. Apt 6
City: Lynn
State: Massachusetts
Country: United States of America
Appl. No.: 13/680,256
Appl. Filed: August 7, 2014
U.S.
Classification:
|
125/13.01 125/22 299/10
299/15 299/79.1 299/100 407/30 407/113 464/16
|
CPC
Classification:
|
B28D 1/045; B28D
1/122 ; E21C 41/16; B28D 1/088; E21C 35/19;
B25D 17/02; B23C
5/10; B23C 2200/125; F16D 3/185
|
International
Classification:
|
B28D 1/04; B28D 1/12 ;
E21C 37/00; E21C 41/00; E21C 25/10;
B26D 1/12; B23P
15/28; F16D 3/18
|
Reference
Citations
U.S.
Patent Citations
451199
|
April
1891
|
Kessbler
|
1670723
|
August
1924
|
Hummel
|
2509163
|
February
1947
|
Musselman
|
3695722
|
February
1970
|
Errut
Products Ltd.
|
4035912
|
November
1975
|
Weed
Eater, Inc.
|
4232505
|
August
1978
|
The
Toro Co.
|
4750468
|
December
1985
|
Micheletti
|
4572258
|
February
1986
|
Mischel
|
5771670
|
December
1995
|
Perry
|
5844160
|
May
1997
|
Caterpillar
Inc.
|
6427429
|
April
2001
|
Brabenec
|
0246939
|
October
2007
|
McDonald
|
Claims
The invention claimed is:
1. A centrifugal masonry saw system for precision-cutting stone, suitable for quarrying, comprising: a central axle member adapted to be rotated by staves inserted in the middle, supported on two parallel guide-beams, with copper-plated triangular grooves in said axle fitted into matching copper-plated triangular protrusions of said guide-beams. Said guide beams are supported above the ground by pole-struts. Each free end of said axle contains a pair of orthogonal holes, through which pass, braided cords of animal fiber (ie. cured camel intestine), attached to the ends of the cords are copper cutting heads (said cutting heads are composed of emorized copper = sand mixed into copper ore when smelted) of balanced weight adapted to rotate in concert with the central axle about its axis when turned by said staves, rotating on said supporting guide-beams lubricated with animal fat, wherein said copper cutting heads come into contact with the rock beneath the saw, repeatedly striking the stone on each rotation, gradually grinding a cut into the rock. A pair of vertical propulsion-beams, unattached to said axle and support structure, in front of, and in contact with said axle, positioned to either side of said central staves, may be moved to propel the axle along the guide-beams, thus controlling the advance of the saw and the cut. The propulsion-beams are connected by beam supported by an anchored guide-beam, whereby smooth control of the axle advance and resulting cut is possible {Class 125/12 - Sawing Patent}.
2. The centrifugal saw system of claim 1, wherein said axle is horizontally orientated and freely rotatable along its long axis.
3. The centrifugal saw system of claim 1, wherein said axle is comprised of an elongated solid cylinder, with two copper-plated triangular grooves carved into either end, at roughly one eighth length. The copper-plating reduces friction.
4. The centrifugal saw system of claim 1, wherein said guide-beams are two symmetric, parallel beams, oriented horizontally, perpendicular with respect to said axle.
5.
The centrifugal saw system of claim 1, wherein said guide-beams are comprised
of flat, rectangular surfaces, excepting the top surface, which is a raise copper-plated
triangular protrusion on the upper surface, a slightly more acute triangle than
the triangular groove in said axle.
6. The centrifugal saw system of claim 1, wherein said guide-beams are spaced precisely the distance apart to sit directly under the triangular grooves in said axle, whereon said axle is supported, and whereby the coupling of said triangular groove with said triangular guide-beam fixes said axle (prevents slipping) {Class 464/16 - Rotary Shafts, Gudgeons, Housings and Couplings / Self-centering or floating}.
7. The centrifugal saw system of claim 1, wherein said coupling of copper-plated triangular groove with copper-plated triangular guide-beam minimizes the contact surface area, minimizing friction.
8. The centrifugal saw system of claim 1, wherein said animal fat applied to the surfaces of the triangular coupling between said axle and said guide-beam further minimizes friction.
6. The centrifugal saw system of claim 1, wherein said guide-beams are spaced precisely the distance apart to sit directly under the triangular grooves in said axle, whereon said axle is supported, and whereby the coupling of said triangular groove with said triangular guide-beam fixes said axle (prevents slipping) {Class 464/16 - Rotary Shafts, Gudgeons, Housings and Couplings / Self-centering or floating}.
7. The centrifugal saw system of claim 1, wherein said coupling of copper-plated triangular groove with copper-plated triangular guide-beam minimizes the contact surface area, minimizing friction.
8. The centrifugal saw system of claim 1, wherein said animal fat applied to the surfaces of the triangular coupling between said axle and said guide-beam further minimizes friction.
9.
The centrifugal saw system of claim 1, wherein said pole-struts are comprised
of a minimum of four poles oriented vertically, perpendicular to said
guide-beams.
10.
The centrifugal saw system of claim 1, wherein said symmetric pole-struts are
solid cylinders of equal length, with one end anchored to the ground and the
other end fixed to said guide-beams, lashed together with cured animal cord,
whereby said guide-beams are anchored in place at a height slightly less than
half the length of said braided cords tipped with said cutting bits.
11. The centrifugal saw system of claim 1, wherein said staves are comprised of four rods, roughly one sixth the diameter of said axle, and inserted into said axle at its midpoint.
11. The centrifugal saw system of claim 1, wherein said staves are comprised of four rods, roughly one sixth the diameter of said axle, and inserted into said axle at its midpoint.
12.
The centrifugal saw system of claim 1, wherein said staves are inserted perpendicularly
with respect to said axle, and arranged orthogonally to each another, around
the midpoint of said axle, whereby said axle is rotated {Class 125/13.01 - Rotary
Saw}.
13. The centrifugal saw system of claim 1, wherein said cutting teeth are comprised of four braided cords tipped with cutting bits.
14. The centrifugal saw system of claim 1, wherein said braided cord is comprised of sixteen symmetric, equal lengths of cured animal fiber (cured camel intestine) braided into four cords of equal length, roughly ten times the diameter of the axle.
13. The centrifugal saw system of claim 1, wherein said cutting teeth are comprised of four braided cords tipped with cutting bits.
14. The centrifugal saw system of claim 1, wherein said braided cord is comprised of sixteen symmetric, equal lengths of cured animal fiber (cured camel intestine) braided into four cords of equal length, roughly ten times the diameter of the axle.
15.
The centrifugal saw system of claim 1, wherein said cutting tooth head is
comprised of four pairs of balanced (equally weighted) emorized copper cutting
teeth cast in the shape of an ankh, an elongated cross with a hole in the top
{Class 299/79.1 - Mining/Cutter Tooth Head}
16.
The centrifugal saw system of claim 1, wherein the free ends of said braided
cords, comprised of four free fiber ends are run through the hole at the top of
said cutting tooth and woven around the arms of said cutting tooth head,
whereby said cutting tooth head is fixed to the end of said cord {Class 125/22
- Saw Teeth}.
17.
The centrifugal saw system of claim 1, wherein said cutting tooth head is
comprised of roughly between a half kilogram and two kilograms of emorized
copper, emorized copper being copper ore with sand mixed in during the smelting
process, whereby the hardness of the metal is increased .{Class 299/79.1 - Mining/Cutter
Tooth Head}
{Class
299/100 - Mining/Percussive Tooth Bit}
14.
The centrifugal saw system of claim 1, wherein said braided cord engages said
axle by being run through pairs of orthogonal holes bored at both ends of said
axle, whereby the rotation of said axle rotates said cutting teeth in a
circular motion.
16. The centrifugal saw system of claim 1, wherein the rotation of said cutting teeth is hand-powered, with a sustained velocity in excess of two revolutions per second, whereby said braided cord acts as a gear, with a ration of 10:1, multiplying the velocity of said axle by ten fold (ie. in the case of an axle diameter of 1m, the velocity of said cutting teeth is ~65m/s or ~240km/hr.
17. The centrifugal saw system of claim 1, wherein said circular motion of said cutting heads brings them in contact with said stone at the bottom of the circle, whereby said cutting heads strike the stone with each pass, gradually wearing away the surface and producing a cut.
18.
The centrifugal saw system of claim 1, wherein said vertical propulsion-beams
are comprised of two vertically oriented solid beams, perpendicular to said
axle, and in front of said axle.
19.
The centrifugal saw system of claim 1, wherein said propulsion-beams are in
contact with said axle, whereby said axle is prevented from advancing forwards,
in the direction it is rotating. Said propulsion-beams are covered with animal
fat for lubrication to reduce friction.
20.
The centrifugal saw system of claim 1, wherein said vertical propulsion-beams
are connected by a third beam, horizontally oriented, lashed by animal cord to
each propulsion beam fixing the propulsion beams together.
21.
The centrifugal saw system of claim 1, wherein said horizontal,
connecting-beam, is comprised of a freely mobile beam resting on a third
guide-beam, oriented parallel to the other guide beams (ie. the line of the
cut) and fixed to the ground, whereby the horizontal connecting-beam is
supported as it is moved smoothly forwards.
22.
The centrifugal saw system of claim 1, wherein said vertical propulsion-beams
are moved away from the axle, guided by said connecting-beam, whereby
controlling the speed of advance of said saw and of the cut it produces.
23. The centrifugal saw system of claim 1, wherein said saw produces parallel cuts in hard stone, whereby repeating the process with perpendicular cuts produces a stone block attached only on the bottom face.
23. The centrifugal saw system of claim 1, wherein said saw produces parallel cuts in hard stone, whereby repeating the process with perpendicular cuts produces a stone block attached only on the bottom face.
24.
The centrifugal saw system of claim 1, wherein said stone block attached on the
bottom face has dry wooden rods driven into two perpendicular cuts, and said
rods are subsequently soaked with water, whereby said stone block is
quarried. {Class 299/15 Mining/Forming
blocks (e.g., quarrying)}
25.
The centrifugal saw system of claim 1, wherein the cutting process is repeated
on said quarried stone block, whereby the stone is shaped and dressed. {Class
407/30 – Cutters for Shaping / Rotary Cutting Tool}
26.
The centrifugal saw system of claim 1, wherein said rotating cutting tool is
comprised of a pairs of rotating cutting edges, whereby symmetric cuts shape
uniform blocks of stone. {Class 407/113 – Cutters for Shaping / Tools having
Plural, Alternatively Usable Cutting Edges}
27.
The centrifugal saw system of claim 1, wherein the process of cutting stone
blocks with a hand-powered saw to shape or quarry them. {Class 299/10 Mining/Process}
Description
CROSS
REFERENCE TO RELATED APPLICATIONS
Not applicable to this application.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not applicable to this application.
BACKGROUND OF THE INVENTION
Not applicable to this application.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not applicable to this application.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to a hand-powered, centrifugal masonry saw and more specifically it relates to a mechanical saw for small groups of individuals, with limited resources to cut large blocks of stone with a high-precision of smoothness along the cut faces, facilitating subsequent manipulation of said blocks and creation of stable, large-scale, monumental structures. No hand-powered masonry machines are currently under patent.
2. Description of the Related Art
Any discussion of the related art throughout the specification should in no way be considered as an admission that such related art is widely known or forms part of common general knowledge in the field.
Conventional masonry saws are comprised of a rotating circular cutting head with special, hardened teeth (typically with diamonds) that is powered by a motor to generate sufficient torque and cutting force to cut stone. The problem with conventional masonry saws is that the motor and energy to power are unreliable (break down) and re-supply (or a replacement part) is not always available in all locations. Restoration of ancient monuments seeks to restore ancient edifices with authentic replicas, using tools and techniques as close as possible to the original methods. In addition, some contemporary societies (such as the Amish) insist on working with tools without motors.
Because of the lack of hand-powered stone cutting machines, there is a need for a new and improved hand-powered saw for cutting stone, with precision suitable to producing blocks for use in monumental architecture.
BRIEF SUMMARY OF THE INVENTION
The invention generally relates to a centrifugal masonry saw which includes a centrally rotating axle, with four staves fixed at its mid-point, which can be pulled by workers to generate rotation. The axle rotation is coupled to four braided cords. A pair of cords is engaged with the axle at each end, by being run through holes bored through the axle. The axle is rotated freely upon, and supported by, perpendicular guide-beams, which in turn are supported and fixed to the ground by pole-struts. Triangular grooves in the axle are coupled to a triangular surface on the guide-beams, to fix the axle rotation and prevent slippage. The rotation of the axle causes the axle to advance forward, along the guide-beams. Vertical propulsion beams placed in front and in contact with the axle restrict and control the advance of the axle. The length of braided cord functions as a gear, with a gear ratio of 10:1; converting the circumferential velocity of rotation of the axle into a ten-fold circumferential velocity of the cutting tooth heads at their tip. The balanced cutting tooth heads generate equal and opposite centrifugal forces on the braided cord cancelling one another. The resultant system requires no net force to generate rotation, other than the force necessary to overcome friction. The triangular coupling of the axle with guide-beams reduces friction to a negligible amount; that produced by roughly two centimeters of contact between lubricated surfaces. Minimal force is required to overcome friction and generate rotation of the axle, which is transferred into high-velocity rotation of the emorized copper cutting heads (sand hardened copper). The considerable velocity and mass of the cutting tooth heads generate sufficient cutting force to cut any species of rock.
There has thus been outlined, rather broadly, some of the features of the invention in order that the detailed description thereof may be better understood, and in order that the present contribution to the art may be better appreciated. There are additional features of the invention that will be described hereinafter and that will form the subject matter of the claims appended hereto. In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction or to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of the description and should not be regarded as limiting.
BRIEF DESCRIPTION OF THE DRAWINGS
Various other objects, features and attendant advantages of the present invention will become fully appreciated as the same becomes better understood when considered in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the several views, and wherein:
FIG. 1* is an upper perspective view of the present invention.
FIG. 2* is a frontal view of the present invention.
FIG. 3* is a side view of the present invention.
FIG. 4* is an overhead view of the present invention.
FIG. 5* is a side view of the cutting head in action, demonstrating the radial cutting head arc.
FIG. 6* is a detailed close-up view of an individual cutting head and a cutting head attached to a rotating cord.
FIG.
7 is a close-up view of the vertical propulsion-beams, connecting-beam and
grounded guide-beam
*Figures 1-6, do not show the vertical propulsion-beams, connecting-beam and grounded guide-beam system.
*Figures 1-6, do not show the vertical propulsion-beams, connecting-beam and grounded guide-beam system.
DETAILED
DESCRIPTION OF THE INVENTION
A. Overview
Turning now descriptively to the drawings, in which similar reference characters denote similar elements throughout the several views, FIGS. 1 through 7 illustrate a centrifugal saw system 1, which comprises an axle 30 freely rotatable, with a pair of copper-plated triangular grooves 40, which are coupled to the copper-plated triangular surface 41 of a pair of parallel guide-beams 31 fixed to the ground by pole-struts 32. The triangular coupling is lubricated with a coating of animal fat 46. At the center of the axle 30, staves 33 are fitted that can be pulled to produce rotation of the axle 30. At either end of the axle 30, pairs of braided cords 34 run through hole bored in the axle 35. Attached to the ends of the braided cords 34 are emorized copper cutting tooth heads 36. The rotation of the axle 30 is transferred to the copper cutting heads 36 with a gear ratio of 10:1 [38]. The rotation of the axle 30 causes forward advance along the guide-beams 31. The forward advance of the axle 30 is controlled by vertical propulsion-beams 39 unified by a connecting-beam 44, which slides upon a grounded guide-beam 45. The contact-points of the axle 30 with the propulsion-beams 39 are lubricated with a coating of animal fat 46. The present invention may be used to cut, shape, dress and quarry stone.
B. Axle
FIG. 2 best illustrates the axle 30 resting freely on, and pivotally coupled to, guide-beams 31 at either end. The axle 30 is positioned horizontally, supported on guide-beams 31 which in turn are fixed atop pole-struts 32 a significant height above the stone to be cut. The height of the axle 30 is determined by the length of the braided cords 34 which must be slightly longer than the height of the axle 30. The actively rotating axle 30 transfers rotational motion to the braided cords 34 tipped with cutting tooth heads 36, which follow a wide circular arc as illustrated in FIG. 6 of the drawings. Because the height of the axle 30 is less than half the length of the braided cords 34, the circular arc is wide enough to bring the cutting tooth heads 36 into contact with the stone at the bottom of their circular path, which results in cutting.
The axle 30 is typically comprised of a horizontally orientated, solid cylindrical structure, similar in size and shape to modern telephone poles. The axle 30 preferably rotates towards the users, allowing users to engage the staves 33 with pulling motions as the axle 30 advances towards them along the guide-beams 31, said advance being controlled by users on either side of the ‘stave-pullers’ manning the propulsion-beams 39.
It is preferable that the pole-struts 32 function as ‘emergency brakes’, protruding above the guide-beams 31 and blocking the axle 30 from advancing off the ends of the guide-beams 31.
A. Overview
Turning now descriptively to the drawings, in which similar reference characters denote similar elements throughout the several views, FIGS. 1 through 7 illustrate a centrifugal saw system 1, which comprises an axle 30 freely rotatable, with a pair of copper-plated triangular grooves 40, which are coupled to the copper-plated triangular surface 41 of a pair of parallel guide-beams 31 fixed to the ground by pole-struts 32. The triangular coupling is lubricated with a coating of animal fat 46. At the center of the axle 30, staves 33 are fitted that can be pulled to produce rotation of the axle 30. At either end of the axle 30, pairs of braided cords 34 run through hole bored in the axle 35. Attached to the ends of the braided cords 34 are emorized copper cutting tooth heads 36. The rotation of the axle 30 is transferred to the copper cutting heads 36 with a gear ratio of 10:1 [38]. The rotation of the axle 30 causes forward advance along the guide-beams 31. The forward advance of the axle 30 is controlled by vertical propulsion-beams 39 unified by a connecting-beam 44, which slides upon a grounded guide-beam 45. The contact-points of the axle 30 with the propulsion-beams 39 are lubricated with a coating of animal fat 46. The present invention may be used to cut, shape, dress and quarry stone.
B. Axle
FIG. 2 best illustrates the axle 30 resting freely on, and pivotally coupled to, guide-beams 31 at either end. The axle 30 is positioned horizontally, supported on guide-beams 31 which in turn are fixed atop pole-struts 32 a significant height above the stone to be cut. The height of the axle 30 is determined by the length of the braided cords 34 which must be slightly longer than the height of the axle 30. The actively rotating axle 30 transfers rotational motion to the braided cords 34 tipped with cutting tooth heads 36, which follow a wide circular arc as illustrated in FIG. 6 of the drawings. Because the height of the axle 30 is less than half the length of the braided cords 34, the circular arc is wide enough to bring the cutting tooth heads 36 into contact with the stone at the bottom of their circular path, which results in cutting.
The axle 30 is typically comprised of a horizontally orientated, solid cylindrical structure, similar in size and shape to modern telephone poles. The axle 30 preferably rotates towards the users, allowing users to engage the staves 33 with pulling motions as the axle 30 advances towards them along the guide-beams 31, said advance being controlled by users on either side of the ‘stave-pullers’ manning the propulsion-beams 39.
It is preferable that the pole-struts 32 function as ‘emergency brakes’, protruding above the guide-beams 31 and blocking the axle 30 from advancing off the ends of the guide-beams 31.
Ideally,
six users are required to operate the saw. Three users are required to
continuously engage the staves 33 and rotate the axle 30, rotating in shifts of
two-working-one-resting. Two users are required to man the propulsion-beams 39
and control the advance of the saw cut. One user is required to monitor the
progress of the cut and direct the users manning the propulsion-beams 39.
C. Guide-Beams
FIG. 4 best illustrates the guide-beams 31 oriented horizontally, perpendicular with respect to the axle 30, and running parallel and perfectly equidistant from one another. The guide-beams 31 are fixed atop pole-struts 32, lashed together with animal cords. The height of the axle 30 above the stone to be cut is an important factor that roughly determines the approximate length of the pole-struts 32. The final height of the pole-struts 32 is determined by whatever length is necessary for them to maintain the guide-beams 31 in as near to perfect horizontal orientation as possible.
D. Pole-Struts
FIG. 1 best illustrates the pole-struts 32 attached to the guide-beams 31 and anchoring them to the ground. In practice, undulations of the ground require pole-struts 32 of varying lengths to maintain the guide-beams 32 perfect horizontal orientation, as discussed above, in C. Guide-beams. The pole-struts 32 are comprised of solid material, sufficiently well-anchored to the ground, to avoid any movement during cutting.
E. Staves
FIG. 1 best illustrates the four staves 33 that users pulls to rotate the axle 30 and, in turn, the cutting teeth of the saw. The staves 33 are fitted into holes bored into the axle 30 at equidistant points around its mid-point. The staves 33 represented in FIGS. 2, 3,4 & 5 of the drawings represent alternative locations for inserting the staves 33. The staves 33 are comprised of four rods, an eighth the diameter of the axle 30 as best illustrated in FIG. 1 of the drawings. However, various other configurations for the staves 33 may be utilized. The staves 33 have a diameter sufficient in size and shape to receive a hand-grip of the user to best enable the user to exert maximum pulling force while minimizing the amount of extraneous effort necessary to release and re-engage the next stave 33 during continuous axle 30 rotation. The staves 33 are protruding a short distance from the axle 30, which is positioned a significant height above the ground and thus a platform is necessary, running the length of the guide-beams, for users to stand on and walk along while continuously pulling the staves 33 to rotate the axle 30 while cutting; which point is best illustrated in FIG. 4 of the drawings.
F. Braided Cords
FIGS. 3 & 6 best illustrate the braided cords 34 with balanced copper cutting tooth heads 36 attached at each end. The paired braided cords 34 extend orthogonally out from the axle 30 with respect to each other as illustrated in FIG. 3 of the drawings. The braided cords 34 preferably are comprised of four individual lengths of cured animal intestine woven together to form a braided structure having a length approximately a meter longer than the height of the center of the axle 30 as illustrated in FIG. 3 of the drawings, however, various other lengths may be utilized for the braided cords 34, depending on the hardness of the rock and type of cut. The braided cord 34 preferably is attached to the cutting tooth heads 36 by weaving the free ends through the ring at the top of the cutting tooth heads 36 and around the horizontal arms of the cutting tooth heads 36 and knotted together above the arms, as illustrated in FIG. 6 of the drawings. The process of attaching the braided cords 34 to the cutting tooth heads 36 should be done before curing the cords (ie. while the tissue is still flexible). Curing of the braided cords 34 results in a material with more than sufficient tensile strength to resist the centrifugal force generated by the copper weights rotating at maximum velocity. Curing of the braided cords generates a material with minimal stretch and slidability under the extremely high tensions produced during cutting. Curing the braided cord 34 ends fuses the knots into links with high tensile strength that securely attach the copper cutting tooth heads 36.
G. Cutting Tooth Head
The Cutting Tooth Heads 36 are fix to ends of the braided cords 34 as illustrated in FIG. 6. The engaging cutting head 36 preferably contacts the stone at the bottom of the rotational arc as illustrated in FIG. 6 of the drawings. The impact of the cutting tooth heads 36 on the stone results in a percussive cutting action. The cutting tooth heads 36 are comprised of copper ore mixed with sand during smelting that has been cast into an ankh shaped object. Balanced (equal weights) pairs of cutting tooth heads 36 are attached to either end of a braided cord 34 after the cord is passed through the hole bored in the axle 30. Together the braided cords 34 and cutting tooth heads 36 comprise the cutting teeth of the saw and are freely mobile within the axle 30. The mobility of the braided cords within the axle 30 prevents the possibility of catastrophic damage when a braided cord 34 breaks or a cutting tooth head 36 breaks off. The free mobility also ensure the cutting tooth heads 36 retain equal weights as they where down during the cutting process. As one cutting tooth head 36 wears away more than the other, the other’s greater weight propels it outwards, resulting in its striking more of the stone and wearing away to restore balance.
The sand mixed with the copper ore gives the cutting tooth heads 36 greater hardness than pure copper, the amount of hardness depends on the type of sand used. In theory, hard crushed stone, such as granite, could be used.
H. Propulsion-Beams
Propulsion beams are not represented in the drawings presented. The propulsion beams are two-inch thick, eight feet long, smooth, polished poles ending in an orthogonal ‘T’ cross-piece at the end furthest from the holder. The flat end of the propulsion beams enables the worker holding it to apply pressure against the rotating axle, forcing it slowly along the Guide-beams.
C. Guide-Beams
FIG. 4 best illustrates the guide-beams 31 oriented horizontally, perpendicular with respect to the axle 30, and running parallel and perfectly equidistant from one another. The guide-beams 31 are fixed atop pole-struts 32, lashed together with animal cords. The height of the axle 30 above the stone to be cut is an important factor that roughly determines the approximate length of the pole-struts 32. The final height of the pole-struts 32 is determined by whatever length is necessary for them to maintain the guide-beams 31 in as near to perfect horizontal orientation as possible.
D. Pole-Struts
FIG. 1 best illustrates the pole-struts 32 attached to the guide-beams 31 and anchoring them to the ground. In practice, undulations of the ground require pole-struts 32 of varying lengths to maintain the guide-beams 32 perfect horizontal orientation, as discussed above, in C. Guide-beams. The pole-struts 32 are comprised of solid material, sufficiently well-anchored to the ground, to avoid any movement during cutting.
E. Staves
FIG. 1 best illustrates the four staves 33 that users pulls to rotate the axle 30 and, in turn, the cutting teeth of the saw. The staves 33 are fitted into holes bored into the axle 30 at equidistant points around its mid-point. The staves 33 represented in FIGS. 2, 3,4 & 5 of the drawings represent alternative locations for inserting the staves 33. The staves 33 are comprised of four rods, an eighth the diameter of the axle 30 as best illustrated in FIG. 1 of the drawings. However, various other configurations for the staves 33 may be utilized. The staves 33 have a diameter sufficient in size and shape to receive a hand-grip of the user to best enable the user to exert maximum pulling force while minimizing the amount of extraneous effort necessary to release and re-engage the next stave 33 during continuous axle 30 rotation. The staves 33 are protruding a short distance from the axle 30, which is positioned a significant height above the ground and thus a platform is necessary, running the length of the guide-beams, for users to stand on and walk along while continuously pulling the staves 33 to rotate the axle 30 while cutting; which point is best illustrated in FIG. 4 of the drawings.
F. Braided Cords
FIGS. 3 & 6 best illustrate the braided cords 34 with balanced copper cutting tooth heads 36 attached at each end. The paired braided cords 34 extend orthogonally out from the axle 30 with respect to each other as illustrated in FIG. 3 of the drawings. The braided cords 34 preferably are comprised of four individual lengths of cured animal intestine woven together to form a braided structure having a length approximately a meter longer than the height of the center of the axle 30 as illustrated in FIG. 3 of the drawings, however, various other lengths may be utilized for the braided cords 34, depending on the hardness of the rock and type of cut. The braided cord 34 preferably is attached to the cutting tooth heads 36 by weaving the free ends through the ring at the top of the cutting tooth heads 36 and around the horizontal arms of the cutting tooth heads 36 and knotted together above the arms, as illustrated in FIG. 6 of the drawings. The process of attaching the braided cords 34 to the cutting tooth heads 36 should be done before curing the cords (ie. while the tissue is still flexible). Curing of the braided cords 34 results in a material with more than sufficient tensile strength to resist the centrifugal force generated by the copper weights rotating at maximum velocity. Curing of the braided cords generates a material with minimal stretch and slidability under the extremely high tensions produced during cutting. Curing the braided cord 34 ends fuses the knots into links with high tensile strength that securely attach the copper cutting tooth heads 36.
G. Cutting Tooth Head
The Cutting Tooth Heads 36 are fix to ends of the braided cords 34 as illustrated in FIG. 6. The engaging cutting head 36 preferably contacts the stone at the bottom of the rotational arc as illustrated in FIG. 6 of the drawings. The impact of the cutting tooth heads 36 on the stone results in a percussive cutting action. The cutting tooth heads 36 are comprised of copper ore mixed with sand during smelting that has been cast into an ankh shaped object. Balanced (equal weights) pairs of cutting tooth heads 36 are attached to either end of a braided cord 34 after the cord is passed through the hole bored in the axle 30. Together the braided cords 34 and cutting tooth heads 36 comprise the cutting teeth of the saw and are freely mobile within the axle 30. The mobility of the braided cords within the axle 30 prevents the possibility of catastrophic damage when a braided cord 34 breaks or a cutting tooth head 36 breaks off. The free mobility also ensure the cutting tooth heads 36 retain equal weights as they where down during the cutting process. As one cutting tooth head 36 wears away more than the other, the other’s greater weight propels it outwards, resulting in its striking more of the stone and wearing away to restore balance.
The sand mixed with the copper ore gives the cutting tooth heads 36 greater hardness than pure copper, the amount of hardness depends on the type of sand used. In theory, hard crushed stone, such as granite, could be used.
H. Propulsion-Beams
Propulsion beams are not represented in the drawings presented. The propulsion beams are two-inch thick, eight feet long, smooth, polished poles ending in an orthogonal ‘T’ cross-piece at the end furthest from the holder. The flat end of the propulsion beams enables the worker holding it to apply pressure against the rotating axle, forcing it slowly along the Guide-beams.
I.
Stabilizing Cross-Beams
Not pictured in the drawings, four Stabilizing Cross-beams are fixed diagonally from the top of each pole strut to the base of the opposing pole-strut (ie. The base of the pole strut supporting the facing, parallel guide-beam). The fixed cross-beams anchor and stabilize the pole-struts and thus the guide-beams.
Not pictured in the drawings, four Stabilizing Cross-beams are fixed diagonally from the top of each pole strut to the base of the opposing pole-strut (ie. The base of the pole strut supporting the facing, parallel guide-beam). The fixed cross-beams anchor and stabilize the pole-struts and thus the guide-beams.
J.
Grounded Guide-Beam
Initially, in the ‘start-up’ phase, while the axle 30 is being brought from a motionless state up to a ‘cutting’ velocity of two revolutions per second, the ‘Propulsion-Beams’ 39 are kept in the stop position (FIG. 7), in front of the axle 30, contacting the axle 30 and preventing it from moving along the ‘Guide-beams’ 31
Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although methods and materials similar to or equivalent to those described herein can be used in the practice or testing of the present invention, suitable methods and materials are described above.
All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety to the extent allowed by applicable law and regulations. In case of conflict, the present specification, including definitions, will control. The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof, and it is therefore desired that the present embodiment be considered in all respects as illustrative and not restrictive. Any headings utilized within the description are for convenience only and have no legal or limiting effect.
Initially, in the ‘start-up’ phase, while the axle 30 is being brought from a motionless state up to a ‘cutting’ velocity of two revolutions per second, the ‘Propulsion-Beams’ 39 are kept in the stop position (FIG. 7), in front of the axle 30, contacting the axle 30 and preventing it from moving along the ‘Guide-beams’ 31
Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although methods and materials similar to or equivalent to those described herein can be used in the practice or testing of the present invention, suitable methods and materials are described above.
All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety to the extent allowed by applicable law and regulations. In case of conflict, the present specification, including definitions, will control. The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof, and it is therefore desired that the present embodiment be considered in all respects as illustrative and not restrictive. Any headings utilized within the description are for convenience only and have no legal or limiting effect.
FIGURES
FIGURE
1
FIGURE
2
FIGURE 3
FIGURE 4
FIGURE 6
Saturday, May 31, 2014
Hand-Powered Stone Saw [ background discussion ]
Design for Hand-Powered Stone Saw
Jonathan Sheetz, M.D.
It is still not clear how ancient Egyptian stone masons cut stone. It would seem that ancient Egyptian masons had at their disposal a tool that is not used by modern stone masons to cut stone, one that could be made from materials available to the ancient Egyptians.
A ‘new’ type of circular saw design, a “centrifugal saw” which generates sufficient cutting force for cutting stone on an industrial scale and could have been made of material available to ancient Egyptians may be an answer. The “centrifugal saw” presented here resembles a large scale garden-trimmer with rotating copper-tipped cords spun on a vertical axis by a central wooden cylinder axle. The cutting properties of a “centrifugal saw” are compatible with the work left by ancient Egyptian masons; including the industrial scale of precision stone cutting of hard rock.
(photographs: Francis)
The pyramids of Giza are the most famous example of the astounding skill of Egyptian stone masons five thousand years ago. There are some 2.5 million limestone blocks used to build the Great Pyramid of Gizah with an average size of 4’ x 4’ x 2.5’, equal to 40 cubic feet and an average weight of 5,000 lbs (2.5 tons). Stone for the Great Pyramid was cut on an industrial scale. There persists debate over the tools and methods employed by the ancient Egyptians to cut stone. James states the mystery clearly “key industrial tools [of the ancient Egyptians] are unknown… these include a stonecutting tool” (James 2003). Moreover, in addition to the limestone blocks, the Great Pyramids contained several granite blocks, which are much more difficult to cut.
Ancient stone masons somehow produced large quantities of stone, cut to a high precision, with access neither to modern tools nor to modern power. Modern stone masonry tools are often powered by motors, while ancient Egyptian stone masons relied on human labour for power.
W.M.F. Petrie, noted that ancient Egyptian possessed a complete set of ‘modern’ masonry tools at their disposal : “They comprised bronze saws over eight feet long, set with jewels, tubular drills similarly set with jewels, and circular saws.” (Petrie 1883)
Archeologists have found evidence of nearly all the same tool designs used by modern stone masons to work stone. Modern stone masons can use a variety of tools to cut stone: chisels with hammers, drills, lathes, planers, circulating saws and reciprocating saws. However, ancient stone masons did not have the same materials from which modern stone masonry tools are made; modern stone masonry kit is made of advanced materials, such as tempered steel, metal alloys and diamond tips. Tools, made of material available to ancient Egyptians, cannot explain how they cut hard stone on an industrial scale. “The methods used [by ancient Egyptian stone masons] to quarry hard stone, particularly granite, are debated” (Novokshchenov 1996).
(photograph: Francis)
Francis noted the extraordinary precision with which ancient Egyptian masons cut stone.
You can see long saw cuts going through this hard rock very quickly. In most cases it can be seen that the cut is straight and clean with smooth, consistently parallel sides - even at the start of the cut. They show no trace of the 'walking' or wobble that might be expected of a long hand pulled blade as it starts into a hard material. (Francis )
Authors typically allude to this mystery, rather than explicitly state the fact, that no modern tool design in use by stone masons, made from material available to ancient Egyptians (copper, wood and stone), has the cutting properties necessary to cut hard stone to the precision with which stones were cut by ancient Egyptian masons. The mystery deepens when one considers how the ancient Egyptians might have generated an ‘industrial’ scale output of cut stone. The scale has been the subject of studies that have tried to characterize it and make “an assessment of the industrial nature of the enterprise” (Ashton 1994)
A “centrifugal saw” is a tool that could have been used by the ancient Egyptians to produce an industrial scale output of high-precision cut stone. The “centrifugal saw” is a design not used by modern stone masons. Nevertheless, “back of the envelope” calculations suggest a ‘centrifugal saw’ generates cutting forces comparable to those generated by a modern ‘diamond-tipped’ disc saw used to cut granite stone. It is also a tool made of material available to ancient Egyptians: emery copper, cured leather (or intestine) and wood. Moreover, a “centrifugal saw” could cut stone on an industrial scale, with a speed approximating that of modern saws. Another feature of the “centrifugal saw”s design, the outward force on its cutting blades would naturally produce smooth, straight cuts orthogonal to the machine’s axle (simplifying the process of producing perfectly squared, right angle blocks).
As stated, all of the materials necessary to build a Hand-Powered “centrifugal saw” were available to the ancient Egyptians.
The machine uses a series of wooden cogs to transfer (and perhaps multiply) the force of human labor to a rotating wooden axle, the machine’s core. This central axle is made from a cylindrical shaft of wood. Wood was available to ancient Egyptians. The machine’s cutting heads are made of emery copper attached to the central axle by braided cords of cured leather (or intestine). Cured leather (or intestine) has sufficient tensile strength to withstand the centripetal force generated by swinging a 1 kilogram cutting head around a 30 meter circle once a second. Emery copper has the hardness necessary to cut through hard stone. Emery copper is made of smelted copper mixed with quartz grains (sand) producing a tool “almost as hard as modern diamond-set tools”(Novokshchenov 1996), a process originally suggested by the famous Egyptologist W.F. Petrie (Petrie 1883).
Calculations show that the cutting force generated by a “centrifugal saw” is comparable to the cutting force generated by a modern, diamond-tipped disc saw. The “back of the envelope” calculations are based on a “centrifugal saw” designed to swing 1 kilogram cutting heads around in a circle 10 meters in diameter, once every second.
The circle has a circumference of 31.4 meters. The velocity of the cutting heads are thus 31.4 m/s.
The proposed means of attaching the copper cutting heads, cured, braided leather (or intestines) would have adequate tensile strength to withstand the centrifugal forces involved. The maximum centrifugal Force (Fc) of such a “centrifugal saw” is equal to the mass of the cutting head times the square of the velocity, divided by the radius: that is 197 Newtons (ie. kg*m/s2).
The cutting Force of the centrifugal saw can be calculated from the formula F = m(Δv/Δt), which is; the Force is equal to the mass times the change in velocity divided by the change in time.
The saw has a 30 m circumference and completes 1 revolution per second. Assume that it is in contact with the stone for 1 m of that revolution (about 3 feet), a time of 0.03 seconds. Assume that over these 0.03 seconds, the cutting head slows from 30 m/s to 28 m/s during its cut. Then, the tangential (cutting) force, Ft, will be equal to 1 kg, times 2 m/s, divided by 0.03 s: that is a cutting force = 60 Newtons (ie. 60 kg*m/s2). Comparing these calculations to data measured for existing (modern) granite stone saws suggest that such a maximum tangential force is more than sufficient to cut granite.
Segade et al measured force, including the tangential force, involved in a modern disc saw cutting granite. The study showed that tangential forces of between 10 N and 50 N were adequate to cut granite, when the cutting heads were rotating “at a speed of 30 m/s.”(Segrade 2010)
Such figures for tangential force suggest the eminent potential of the “centrifugal saw” to cut granite, and other stone, on an industrial scale.
A prototype of the suggested design cut through cardboard with ease - at the predicted rpm.
Photos of the prototype cutting blades:
A prototype of the suggested design cut through cardboard with ease - at the predicted rpm.
Photos of the prototype cutting blades:
A video of the prototype
The question remains, if the potential to cut stone with a “centrifugal saw” is so promising, ‘why have such saws not been suggested by the archeological evidence?’
It could be argued that the Egyptians simply neglected to picture the saw in their images (drawn in tombs and cut on monuments), and that nothing remains to be found of the saws themselves. The lack of remains could be explained by arguing that the Egyptians surely recycled the precious copper cutting heads and the wood and animal cords would have decomposed long ago.
Regardless, work needs to be done to review the archeological record for possible evidence of a “centrifugal saw”.
It may be that no archeological evidence has been found suggesting a “centrifugal saw” because none was sought. The shape of the cutting heads is unknown. But, it may be that the ancient Egyptians could have used the predictable shape of a ‘half-moon’ cutting blade. Above this they could have had two ‘wings’ to ensure the blades swung true. And, at the top they could have had a hole to attach the cord to the cutting head. A cutting head in such a form, or a representative of such a shape may exist in the archeological record, and not have been identified as a stone cutting tool.
Likewise, it is possible that the ancient Egyptians did represent a “centrifugal saw” in images and that archeologists did not recognize such images as a tool for cutting stone.
The modern process of cutting with a rotating disc saw, and the associated forces, are described by Segrade:
Segment cutting can be considered as abrasion at multiple contact points (diamond grains) at different passing depths. Only a few grains of diamond form part of the abrasion process on each pass. The main parameters for diamond disc cutting are, cutting speed, vs, is the tangential velocity of the [cutting head] at the moment of cutting; feed speed, vw, is the velocity at which the disc’s axle is moved relative to the rock; and pass depth, ap, is the depth at which the disc penetrates into the rock at each pass.(Segade 2010).
However encouraging such figures, the process of cutting stone is complex and the calculations cannot be definitive. It is recognized that there is clearly need for real-world testing of the “centrifugal saw”.
Other caviates require further investigation and further elucidation in detail. The attachment of the copper ‘head’s to the leather (or intestinal) cord needs to be done in a manner that makes it strong enough to withstand tremendous centrifugal forces. The copper ‘head’s must be balanced to equalize the centrifugal forces.
References:
1. Ashton, B.G. (1994). Ancient Egyptian Stone Vessels: Material and Forms. Heidelberg Orientverlag.
2. Fonte, G.C.A. (2007). Building the Great Pyramid in a Year. Algora, NY.
3. James, F.E. (2003). Building the great pyramid: Probable construction methods employed at Giza. Technology and Culture, 44(2), 340-354. Retrieved from http://search.proquest.com/docview/198436758?accountid=33851
4. Novokshchenov, V. (1996). Pyramid power. Civil Engineering, 66(11), 50-50. Retrieved from http://search.proquest.com/docview/228530926?accountid=33851
5. Petrie, W.M.F (1883). The Pyramids and Temples of Gizeh. London: Field and Taer.
6. Segade et al (2010). The rock processing sector: Part II: Study of cutting forces. Dyna, 77(161), 77-87.
7. Stock, D. (2003). Experiments in Egyptian Archeology: Stoneworking Technology in Ancient Egypt. Routledge. NY.
8. Francis, R. Stone Saws. The Global Education Project. Retrieved from http://www.theglobaleducationproject.org/egypt/articles/hrdfact2.php
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