Diamond saw

A diamond saw for cutting hard materials, in which a steel plate is fixed with a sintered abrading body consisting of diamond abrasive granules and a bonding metal powder, characterized in that a plurality of grooves are provided on the surface of both the front and back side faces of the sintered abrading body.

BACKGROUND OF THE INVENTION 
This invention relates to an improvement in a diamond saw, and more 
particularly in a sintered abrading body including diamond abrasive 
particles embedded in a matrix. 
Circular saws and plate-form saws are known as tools for cutting hard 
materials. The class of circular saws has two types a continuous type (rim 
type) and a segment type, while plate-form saws are grouped generally into 
gang saws and band saws. 
The following are the merits and demerits in the use of various types of 
these saws: 
(1) The continuous type saw is constructed in such a way that an abrasive 
granule layer is continuously, firmly fixed at the outer circumference of 
a steel disc, so that a stripe-pattern based on saw feeding does not 
appear on the cutting surface of the material to be cut, the finishing 
surface is beautiful, and the saw seldom encounters a breaking accident. 
However, the demerit of the saw is that it has a slow cutting speed. 
(2) The segment type saw is constructed in such a way that an abrasive 
granule layer of segment type is firmly fixed by brazing, leaving spaces, 
at the outer circumference of a steel disc, so that the front edge of each 
segment act as cutting edges to increase the cutting speed. However, this 
saw produces on the finishing surface a stripe-pattern based on the saw 
feeding, and moreover it has a demerit that the segment tends accidentally 
to break. 
(3) As referred to above, the plate-form saws are of two types, the gang 
saw and the band saw. The fixing means of the abrasive granule layer is 
similar as in the segment type saw, and therefore the advantages and 
disadvantages thereof are almost same as in (2) above. 
The inventor of this invention has earnestly studied to make use of the 
merits of the conventional articles and eliminate the demerits thereof, 
and as a result he has succeeded in developing the present invention. 
The major object of the invention is to provide a diamond saw for cutting 
hard materials, in which a steel plate is firmly fixed with a sintered 
abrading body consisting of diamond abrasive granules and bonding metal 
powder, the sintered abrading body including diamond abrasive particles 
embedded in a matrix, characterized in that a plurality of grooves are 
provided on the surface of both the front and back side faces of the 
sintered abrading body, and the grooves are arranged in zigzag phase 
positions. 
According to the invention, the saw's cutting ability is improved compared 
with the conventional articles, the cutting speed is increased, the 
strength of the abrading body including abrasive granules is improved, and 
therefore, the abrading body including abrasive granules is prevented from 
prematurely tearing-off and breaking thereby improving the saw's safety 
when in use. Also, less abrasive granules need be used, and further, saw 
life can be prolonged.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
As referred to above, FIGS. 1 and 2 show examples of a continuous type 
circular saw. Reference numeral (1) designates a disc made of steel, and 
reference (2) is a sintered abrading body including diamond abrasive 
particles embedded in a matrix. The sintered abrading body (2) consists of 
a mixture of diamond abrasive particles and a bonding metal powder. 
Reference (3) designates a plurality of grooves indented on the surface of 
the sintered abrading body, and these grooves (3) have openings, as shown 
in the drawings, at the inside and outside edges of both the front and 
back side faces of the sintered abrading body. The outer circumferential 
flange of the circular steel plate (1) is provided with thin portion (6), 
and the sintered body (2) is simultaneously sintered holding the thin 
portion (6) from both sides. As shown in FIG. 2, the grooves (3) are 
arranged in zigzag phase positions. The edges of the grooves are active as 
a cutting saw thanks to the grooves in such an arrangement, and since a 
great number of grooves are provided the cutting ability is improved while 
the cutting speed increases. Further, the present saw has an excellent 
discharging of chips and an improved radiation efficiency and the ability 
to prevent the saw surface from choking owing to the effective outward 
flow of cooling air or water. 
As shown in FIG. 3, preferably the thin portion (6) is provided with a 
plurality of piercing orifices (7) which can have any desired shape and 
dimension. In fixing the sintered abrading body, the sintered abrading 
body of both the front and back sides are simultaneously sintered in 
integrity thereby being useful for increasing the strength. 
FIG. 4 shows a modification of the thin portion (6), a portion of which is 
replaced by a wire-netting (8) whereby the sintered body (2) is more 
integrated. 
In FIG. 1, reference (5) designates a radial, corrugated portion provided 
in the circular steel plate (1). Such provision of the corrugated portion 
(5) enhances the strength of the circular steel plate, and therefore it 
becomes possible to lower the cost by using steel plate thinner than 
conventional articles. Furthermore, by construction of the saw in such a 
manner that the direction of the corrugations in the corrugated shape is 
radial, not including the center of the disc, it is possible to further 
enhance the strength of the disc. 
In case the diameter of a circular saw is over 300 mm, the saw can be a 
segment type circular saw as shown in FIGS. 5 and 6. In FIGS. 5 and 6, 
reference (10) is an arcuate segment, and one previously sintered as a 
segment is used. The arranging positions of the grooves (3) are in zigzag 
phase in both the front and back sides as in the example of FIGS. 1 and 2. 
In this example, the outer circumferential flange of the circular steel 
plate (1) is not provided with a thin portion. Also, the arcuate segment 
is directly fixed by brazing to the outer periphery (9) of said steel 
plate as in conventional articles, but it is preferable to arrange a 
reinforcing, perforated thin plate or a wire-netting (11) as shown in FIG. 
6, at the center of the arcuate segment. The function and effect of the 
reinforcing, perforated thin plate or the wire-netting are the same as the 
examples of FIGS. 3 and 4. 
FIGS. 7 and 8 shows an example in which the present invention is applied to 
a plate-form saw, i.e. a band saw or a gang saw. In this case each segment 
(12) is rectilinear and the grooves (3) are arranged in zigzag phase in 
both the front and back sides of the segment. This segment (12) is 
sintered in such a state that a reinforcing, perforated plate or a 
wire-netting (13) is held therewithin, and it is all right to secure the 
segment (12) to the base plate (1) by brazing means as in known articles. 
FIGS. 9 and 10 show graphs of comparison between the present saw and the 
conventional saws, and they show the results in which the present saw and 
the conventional saws are compared under the following conditions: 
(1) Sample: 
A: Conventional segment type circular saw 
B: Circular saw of the invention (of the type in FIGS. 1 and 2) 
(2) Size: Both of 105 mm diameter and 2.0 mm thick blade 
(3) Material to be cut: Granite (produced in Inada, Japan) 
(4) Infeed: 7 mm 
(5) Feed: 130 mm/min. 
(6) Number of rotations: 12,000 RPM 
(7) Power supply: Disc grinder (Handy) 
As is clear from FIG. 9, the abrasive loss of the present article B is less 
than about 60% of the conventional article A, while as clear from FIG. 10, 
even if the cutting depth is enlarged the present article does not 
increase the power consumption. That is, it will be evident the present 
article is superior in cutting ability over the conventional article. 
Since the invention is constituted as described above it exhibits the 
following excellent effects, compared with the conventional saws: 
(1) Circular saw: 
a. It has the merits in combination of both the continuous type and the 
segment type. That is, a great number of grooves are provided at both 
sides of the sintered body so that it possesses a cutting ability of the 
segment type and a strength of the continuous type. 
b. By arranging lots of grooves in zigzag phase at both side faces, chips 
are well discharged, radiation effeciency is improved, and choking by 
seizure does not occur, so that cutting ability and working efficiency are 
both improved. 
c. The outer periphery of the base plate is provided with a perforated, 
thin portion or a wire-netting, and the blade portion is simultaneously 
sintered, and therefore the strength is enhanced thereby preventing the 
blade portion from breaking. Accordingly, the safety is ensured very much 
while the saw life is prolonged. 
(2) Plate-form saw: 
The side faces of each segment are provided with lots of grooves, and 
moreover, the saw is reinforced with a perforated, thin plate or a 
wire-netting, so that as a result of tests it has been confirmed that this 
saw has the same function and effect as in the circular saw. 
(3) In any type of saw, by arranging a great number of grooves it will 
suffice to use a less amount of mixture consisting of diamond granules and 
binding metal powder which are used in the sintered abrading body 
including diamond abrasive particles embedded in a matrix, and the present 
saw is economical from the cost point of view. 
FIG. 11 shows another circular saw. Reference numeral (31) designates a 
disc made of steel and reference (32) is a sintered abrading body 
including diamond abrasive particles embedded in a matrix. Reference 
numeral (35) designates a plurality of corrugations provided in each of 
the side faces and reference numeral (34) designates a plurality of 
recesses between corrugations. The sintered abrading body (32) consists of 
a mixture of diamond abrasive particles and a bonding metal powder. 
Reference (33) designates signates a plurality of grooves indented on the 
surface of the sintered abrading body. While the recesses and the 
corrugations of FIG. 1 are of the configuration of rectilinear lines, the 
recesses and the corrugations of FIG. 11 are of the configuration of 
curvilinear lines. In both cases, the recesses are arranged almost 
radially. The abrading body grooves (33) coincide with and communicate 
with the recesses (34) between corrugations (35) of the support disc. The 
abrading body grooves (33) and the corrugations (35) are of the 
configuration of spirally curvilinear lines having optional directions, 
and the grooves are arranged almost radially. 
The disc saw of the present invention for cutting stone materials and the 
like is firmly secured in the circumference of its base plate with a flat, 
ring-like layer comprising diamond abrasive granules. Since diamond 
abrasive granules are expensive it is necessary to make the abrasive 
granule layer as thin as possible. Further, by making the abrasive granule 
layer thin then the cutting power advantageously increases. This 
necessitates it to use a thin steel plate as the base plate, but a thin 
plate cannot be saved from lowering resistance against the external 
bending force. The disc saw of the present invention as illustrated in 
FIG. 1 is provided on the base plate with radial corrugations, so that if 
bending force is applied onto the surface of the base plate in the radial 
direction about the center of the base plate, the base plate is bent about 
the creases of said radial lines. Unlike in FIG. 1, however, the 
embodiment of FIG. 11 does not draw radial lines so that even if said 
bending force is applied onto the base plate the base plate cannot be 
easily bent, allowing the strength of the base plate to be increased 
distinctively. 
U.S. Pat. No. 3,754,359 (Scandaletos) describes two cases, in one of which 
in the abrasive tools the paths of cooling water are constructed with 
rectilineal ribs and in the other of which the paths are constructed with 
curvilineal ribs. It further describes that it increases flow of the 
cooling water to use curvilineal ribs, and therefore the cooling 
capability is enhanced while improving the cutting exhaust. 
This U.S. patent is characterized by making the ribs curvilineal for the 
only purpose of increasing the amount of the pasing water, and it totally 
differs in technical idea from the present invention which intends to 
enhance the strength of the disc saw itself. 
FIGS. 12-16 show still another circular saw. Reference numeral (41) 
designates a disc or base plate made of a hard metal such as steel and 
reference (42) is a ring-like abrasive granule layer including diamond 
abrasive particles embedded in a matrix of metal powder. Reference (43) 
designates a plurality of communication grooves provided on the surface of 
the abrasive granule layer (42). These communication grooves (43) are 
arranged approximately radially on the abrasive granule layer (42) 
extending toward the center of the disc (41) from the periphery thereof. 
A plurality of radially arranged corrugations (45) are formed on both the 
front and back faces (51, 52) of the disc (41) as is evident from FIGS. 12 
and 16. A non-corrugated disc portion (53) is provided radially inwardly 
of the abrasive granule layer (42) and between the corrugated portions 
(45) as may be seen from FIG. 12. 
The communication grooves (43) communicate with the corrugations (45) to 
allow fluid and cut particles to pass easily. The number of communication 
grooves (43) is larger by an integral number than the number of 
corrugations (45) in the disc (41). The corrugations (45) can have any 
desired angle to a radial line passing through the center of the disc 
(41). Preferably, the corrugations (45) are spirally curved as shown in 
FIGS. 12 and 16. 
The flat broad spaces designated with reference (53) in FIG. 12 are 
obtained by decreasing the number of corrugations of the radial, 
corrugated portions (5) in FIG. 1. Since the flat space (53) in FIG. 12 is 
broader than the space between corrugations in FIG. 1, even said spaces 
(53) are filled with a larger amount of fluid (air or water). Therefore, a 
larger amount of water is also fed by means of the pumping action based on 
the rotation of the disc saw thereby increasing the exhausting capability 
to the debris which flows into said spaces (53). On the other hand, a 
larger amount of water enhances the cooling capability, thence the 
radiating capability of the frictional heat. Accordingly, the present 
invention has the effects not only of preventing thermal strain of the 
base plate but also of preventing the deterioration of cutting ability, 
which is caused by the debris which is deposited on the working surface. 
The location of each corrugation (45) on the disc (41) is in the same row 
as the location of the communication groove (43) formed on the surface of 
the abrasive granule layer (42). The corrugations (45) on the disc (41) 
and the communication grooves (43) on the layer (42) can be arranged in 
the same direction or in any desired direction. 
As with the embodiments of FIGS. 4 and 6 a wire-netting can be incorporated 
in the ring-like abrasive granule layer (42). The abrasive granule layer 
and the wire-netting can be firmly sintered together at the outer 
periphery of the disc with the corrugations on the disc and the 
communication grooves (43) on the surface of the abrasive granule layer 
(42) being formed together simul- taneously. 
The diamond saw of FIGS. 12-16, can cut stone materials as well as concrete 
products, rock, ceramics, glass, artificial stones and fiber-reinforced 
plastics. 
Although the invention has been shown and described with reference to 
preferred embodiments, it is obvious that modifications and alterations 
will occur to others upon a reading and understanding of this 
specification. It is intended to include all such modifications and 
alterations insofar as they come within the scope of the appended claims 
or the equivalents thereof. 
The disc saw of the present invention has corrugated portions (5), (35) and 
(45) radially arranged on the surface of the base plate, and the outer 
circumference of the base plate is provided with grooves (3), (33) and 
(43) communicating with said corrugated portions. This allows the debris 
generated between the base plate surface and the wall face of cutting and 
reached the recesses of the corrugated portions to be discharged by the 
flow of air or water. 
According to the present invention, thus it is possible to avoid the 
drawbacks which were likely to occur in conventional disc saws, such as 
lowering cutting capability which is caused by wear of the base plate 
surface owing to the debris being grasped between the base plate surface 
and the wall face of cuttigg, by the thermal strain occurring in the base 
plate or by the clogging of the abrasive granule layer because of the 
debris melt adhered to the layer. 
U.S. Pat. No. 3,742,655 (Oliver) describes a grindstone comprising a base 
plate whose surface is largely bent. This grindstone is a tool which is 
used in rubber tire manufacturing process to shear the black shell in the 
surface of the tire off thereby to expose the white portion. 
Thus the disc saw of the present invention is a tool for cutting the mating 
object whereas said U.S. patent relates to a tool for shearing the surface 
of the mating object off. The two inventions have different technical 
ideas in any aspect of the use, function and structure. 
Additionally, even if by making a device in which the abrasive grit forming 
a cutting blade in the Oliver patent is replaced by the teeth (42) 
comprising diamond abrasive granules as shown in FIG. 1 of U.S. Pat. No. 
3,127,887 (Metzger), such device cannot have the same functions as the 
disc saw of the present invention. Thus it cannot be said that the present 
invention is a technique easily created on the basis of the Oliver patent 
or the Metzger or both of them as known art.