Note: Descriptions are shown in the official language in which they were submitted.
~ ,3
NATURE OF THE INVENTION
The invention relates -to sawing apparatus
and, in particular, -to apparatus for sawing metal bars.
BACKGROUND OF THE INVENTION
Precision cutting of metal bars is usually
carried out by means of a hacksaw, which is power operated
by any suitable power source, and reciproca-tes to and
fro.
This cutting method is slow and costly, and
may be limited as to the depth of cu-t tha-t can be made.
However, -the speed of cutting is res-tricted
by the type of metal, and its hardness, and also by
the physical limitations of the hacksaw blade itself.
Clearly, i-t is desirable as far as possible
to speed up the rate of cutting of such metal bars, pro-
vided thls can be done without loss of accuracy. -
Typically,içnown hacksaw apparatuses are driven
by an engine or motor operating through a mechanical
transmission means. When the hacksaw blades of such
apparatuses contact a workpiece, the force of the blade
against the workpiece varies throughout the stroke.
.:
The speed of the blade also varies throughout the stroke.
In order to apply a more constant force to -the workpiece
and to move the blade at a more constant speed, bulkier,
anl heavier and~more complex transmissions would be
re~uired.
Furthermore, the return stroke of a hacksaw - "~
blade during which no cut-ting takes place generally
takes the same amount of time as -the cutting stroke. The
maximum speed of the blade during the cutting stroke
,
:,
323
is pre-determined by factors such as the blade desiyn,
workpiece material and cutting lubricant. Thus, in
order to increase the speed of operation of the hacksaw
appara-tus, only -the speed of the blade during the return
stroke may be increased. However, in order to achieve
such function, the transmission mus-t again be made
bulkier, heavier and more complex.
Of course, such increases in the size and
weight of the hacksaw apparatus add further cost to
the machine. As well, surrounding support struc-ture,
such as a machine foundation, may have to be provided
with increased capacity, also at additional cos-t.
A further disadvantage of known hacksaw appara-
tuses is that the stroke length of a hacksaw blade
is fixed. Thus, for workpieces of varying heights
only a portion of the available blade length may be util-
ized in cutting operations. Such limitation results
in excess wear of a blade in particular areas and of
reduced blade life. In order to overcome this disadvantage,
further weight, bulk, complexity and expense would be
required in the transmission means.
Finally, most known hacksaw apparatuses include
only a single hacksaw, operable therefore only to cut
a workpiece from one side on].y. Such devices are relatively ~;
slow in operation because they can only Cllt from one
side. Known hacksaw apparatuses having two hacksaws
are very~bulky and heavy. The mechanical complexities
of single hacksaw machines are compounded by having
two opposed hacksaws.
The invention t~ereforeprovides two essentially
~':
- 2
2~
parallel spaced apart hacksaw blades, mounted on recipro-
cating support means in opposition to one another, which
can be operated simultaneously so as to cut a bar from both
sides at once.
In accordance with a further objective of the
invention, a table is provided adjacent to such saw blades
and frames, and clamping means are provided for clamping
a work piece on the table.
More specifically, the invention provides two such
saw frames, slidable guide means for sliding such saw frames
towards and away from one another, said slidable guide
means being reciprocable in a plane normal to the plane of
such sliding movement, and power operated means for recipro-
cating said guide means and frame means in unison relative
to a work piece.
More specifically, the power operated means will
comprise at least two, and preferably four, hydraulic
cylinders, and mechanical linkage means connected with said
four cylinders and with said slldable guide means, whereby
to equallze movement of said slidable guide means in response
to operation of said cylinders.
More specifically, the lnvention provides a saw
apparatus having the foregoing advantages in which the
slidable guide means for guiding the blade frames are
slidable towards~and away from one another, by power operated
means, such power operated means being mounted on said
:
- slidable~guide means, and being reciprocable in association
`; :
therewith.~
; ~ Consequently, lt would be advantageous to provide
` a~ double~hacksaw apparatus, the blades of
;` : : ~: ~ ~ :
, :
:.
~ -3-
: .:
~%~
which are operable to apply a relatively constant force
to a workpiece during a cu-t-ting stroke. Furthermore,
such blades ought pre~erably to have a more cons-tant
veloci-ty during -the cutting stroke in order to increase
the overall speed of -the cu-tting operation and in order
to improve the efficiency of the cutting stroke. Such
advantages should be obtained, if possible, without adding
to the bulk, weight or expense of the hacksaw apparatus.
It would also be advantageous, if the speed
of the return stroke of -the hacksaw apparatus couLd
be increased, again without adding to bu:Lk, weight
or cost.
Similarly, it would also be advantageous
to provide a hacksaw apparatus operable to use the
full available length of a hacksaw blade, in order to
improve cutting operation and blade life.
STATEMENT OF THE INVENTION
With a view to overcoming -the above disadvantages
and to providing the above advantages, the invention
~0 comprises:
a hacksaw apparatus, for use in association
with a work piece and a source of pressurized hydraulic
fluid, wherein the hacksaw apparat~s comprises a frame,
adaptable to receive and support the work piece, hydraulic
cy1inder means mounted to the frame, and connectable to
the source of pressurized hydraulic fluid, hacksaw support
structure attached to the hydraul.ic cylinder means, whereby
operation of the hydraulic cylinder means may move the
hacksaw support~ structure relative to the frame, at least
one hacksaw s1idably mounted to the hacksaw support
: .
23
structure, hacksaw movement means operable to move
the hacksaw against the work piece and to maintain
pressure between the hacksaw and the work piece during
a hacksaw cutting stroke.
The hacksaw apparatus according -to the invention
achieves the above advantages by providing a double
hacksaw arrangement, having two hacksaws operable to
cut a workpiece from opposite sides with precision.
Hydraulic power cylinders are provided to reciprocate the
hacksaws, back and forth through each stroke. Other
hydraulic cylinders are provided to force the hacksaw
blades against the workpiece with a uniform, optimum -~
pressure during a cutting stroke. The hydraulic system
includes a pump, operable to deliver a high pressure
hydraulic fluid to the hydraulic power cylinders. The
pump is operable by a sultable control mechanism to
provlde a relatively hlgh flow during the return stroke ~ ~
and a relatively low flow during the cutting stroke. ;
Thus, the hacksaws'return stroke is faster than the
cutting stroke.~
Furthermore,~a clamping mechanlsm is provided
to allow for a variable stroke length of -the hacksaws.
` A limit switch means is attached to a clamp which holds
.~ `'^` ~ ~ , ' :
.. :
)2~
the work piece. As the heigh-ts of various work pieces
change, the clamp holding them moves up and down.
Accordingly, the limit switch means, operable to control
th~ lowermost motion of the hacksaws, moves up and
down as well. The hacksaws thus move up and down suf-
ficiently, whereby the full length of the blade is used
in each cutting stroke.
The various features of novelty which character-
ize the invention are pointed out with particularity
ln in the claims annexed to and forming a part of this
disclosure. For a better understanding of the invention,
its operating advantages and specific objects attained
by its use, reference should be had to the accompanying
drawings and descriptive matter in which there are
illustrated and described preferred embodimen-ts of
the invention. -
IN THE DRAWINGS
Figure 1 is a perspective illustration showing
the sawing apparatus according to the inven-tion mounted
on a frame;
Pigure 2 is a cut-away perspective illustration
showing the sawing apparatus according to the invention;
:,
Figure 3 is a partially sectioned side elevational
view along the line 3-3 of Figure 2 of the hacksaw
blades according to the invention;
Figure 4 is a detailed view along the line ,
,
4-4 of Figure 3;
Figure 5 is a detailed view along the li~e
6 -
-i - . . - . . :
5-5 of Figure 3;
Figure 6 is a view in partial section
along the line 6-6 of Figure 2;
Figure 7 is a view along the line 7-7
of Figure 6;'
Figure 8 is a view of the clamping
apparatus according to the invention along
the line 8-8 of Figure 2, and,
Figure 9 is a schematic view of the
hydraulic sys-tem according to -the invention.
DESCRIPTION OF A SPECIFIC EMBODIMENT
Referring to Figure 1, there is illustrated
a hacksaw apparatus 10 according to the invention.
Hacksaw apparatus 10 comprises a frame 12 to which
is rotatably mounted work table 14. Table 14 is mounted
to frame 12 by any suitable means (not shown) to achieve
such rotatability. Pref~erably, table 14 is rotatable
for at least 45 in either direction from a pre-determined
position. Suitable table clamping means (not shown)
may be used to secure table 14 in a particular selected
angular posltion. Table 14 conveniently defines a
' :
~ :
~ -7-
~ .
:
circular shape. Table 14 deEines slots 16. ~t least
one hacksaw 18 extends upwardly through slots 16.
In the illustra-ted embodiment, a pair of opposed hacksaws
18 are shown. Ilacksaws 18 are each moun~ed -to hydraulic
reciprocating apparatus, indicated generally as 20,
beneath table 14. Slots 16 are wide enouclh -to allow
hacksaws 18 to reciprocate back and forth tnerein. Slots
16 may have different widths at different positions,
according to the width of the portion of the hacksaw
therein. Hacksaws 18 are slidable back and forth
on reciprocating apparatus 20 in order to accommodate
workpieces of different widths. ~ccordingly, slo-ts 16
must define a suitable wic1th to allow such sliding
movement. It is possible (as shown in Figure 1) that
the slots 16 associated with each hacksaw 18 may join
together, thereby defining two halves of table 14 separ-
ated by a gap.
A work piece 22 (shown in Phantom) is clamped
in place on table 14 between hacksaws 18. Figure 1
illustrates the use of table clamp 24 for securing ~;
the work piece 22 to table 14. Other clamping means
may also be used. Table clamp 24 as illustrated provides
certain advantag,es, discussed below, when used in assoc-
iation with reclprocating apparatus 20.
To ensure maximum flex1bility in manufacturing
operations, a separate work piece feeding apparatus
(not shown)~ may be located adjacent to hacksaw apparatus
l0. Such work piece feeding apparatus may be operable to
feed a long or continuous work piece 22 to hacksaws
18 after completlon of a first hacksaw cut-ting operation
~: :
`"'
` ,, .
for a second or subsequen-t cutting operation.
Referring -to Figure 2, hydraulic reciprocating
apparatus 20 is shown in more detail. Only one half
of table 14 is illustrated. ~ffixed to table 14 on
each side of slot 16 and depending generally downwardly
are end support members 26. Each end support member
26 defines a U-shaped slot 28 at its upper end. Slots
28 are thus disposed directly benea-th slo-ts 16. Mounted
to the lower ends of support members 26 are transverse
cross members 30. Each cross member 30 defines a manifold
chamber 46, communicating ~ith -the outside of cross
member 30 (see Figure 6).
Extending vertically from each transverse
cross member 30 are a pair of rods 32. The tops of
rods 32 are each affixed to table 14 and evenly dispose~d
on opposite sides of slot 16.
In the illustrated embodiment, a rod 32 is
affixed to table 14 by means of a bolt 34 passing through
a counter sunk hole 36 defined in a table top 14 into
a threaded hole 38 definèd along the axis of a rod
32 at its upper end.
Referring to Figure 6, the bottom end of a
rod 32 is insert,ed and affixed within a hole 40 defined
through cross member 30 and communicating with manifold
chamber 46. The bottom end of rod 32 defines an axial
bore 42 extending from the bottom of rod 32 approximately
half way up along its length. ~lhe walls of rod 32 near
the bottom of rod 32 define at least one aperture 44
whereby communication~is allowed between bore 42 and the
manifold chamber 46 defined within cross member 30. Manifold
'' ~
_ g _
,, , :
- . .: . . ,., ," ,, ~,
~5~
chamber 46 ex-tends transversely from one side of cross
member 30 by a first rod 32 to the second rod 32.
Manifold chamber 46 and axial bores 42 are sealed around
rod 32 by suitable seal means 66.
Extending ver-tically along the axis of bore 42
is hollow tube 48. An annular chamber 50 is defined between
the walls of tube 48 and of rod 32. Annular chamber
50 communica-tes with the exterior of rod 3, via bores
52 adjacent the top of bore 42. The top of bore 42
defines a tube receiving socket 54 within which -tube
48 is received and sealed. The interior of tube 48
communicates with the exterior of rod 32 via bore holes
56 defined through rod 32 above tube 48 or through
rod 32 and tube 48 at socket 54.
Slidably mounted to the exterior of rods
32 are hydraulic cylinders 58. An annular chamber
60 is defined between cylinder 5~ and rod 32. Annular
chamber 60 is divided into two parts, being an upper
part 60a and a lower part 60b. Chamber parts 60a and
~0 60b are separated by a suitable annular piston/seal
62. ~ore holes 56 communicate with upper chamber 60a `~
and bore holes 52 communicate with lower chamber 60b.
Cylinders 58 are,sealed at each end by suitable seal
means, indicated generally as 64.
Referring aqain to Figure 2, Lower portions of pairs
of cylinders;58 are rigidly connected together by means of a
~:
generally U-shaped hanger member 68. Affixed to the upper portion
of each cyli~nder 58 is a mounting bracket 70. Longi-tudinal
-pairs of brackets 70 are each mounted to a hacksaw
support plate 72, having a generally horizon-tal upper
-- 10 --
.:
~6~
edge, whereby two hacksaw support plates 72 are mounted
to brackets 70 in spaced apart parallel relationship.
Plate 72 may be affixed -to a bracket 70 by any sui-table
means, such as by bolts 74. Plates 72 may be attached
together by suitable spacer members (not shown)
located at pre-détermined specific loca'cions, whereby
such spacer members will not interfere with the operation
of hacksaw apparatus 10, as described kelow.
Referring to Figures 2, 6 and 7, in
order to ensure that the hydraulic reciprocating
apparatus 20 operates generally vertically,
a synchronizing link mechanism, indicated generally
as 76, is provided. Such a synchronizing link mechanism
76 is operable to ensure that hydraulic cylinders 58
operate to move reciprocating apparatus 20 generally
evenly and vertically, maintaining the upper edges
of plates 72 in a generally horizontal position. One
end of transverse cross members 30 defines a vertical
slot 78. An axle rod 80 extends from one cross member
30 to the other and through slots 78 by holes 82 defined
in members 30 for the purpose. Swingably mounted -to
axle rod 80 within slot 78 is a lower link 84. Lower
links 84 are swlngably joined at an upper end to a
synchronizing llnk rod 86. Rigidly mounted to synchro-
nlzing link rod 86 adjacent lower links 84 are upper
links 88. A second end oE upper links 88 is swingably
mounted to hanger member 68. Such swingable mounting
may be achieved by means oE a dowel pin 90 and nut
92. As shown~in Figure 7, it will be appreciated that
upper and lower links 88 and 84, respectively, may
be provlded with bearings 94 ~or ease of ~win~ability~
.
`. ` -11-
. ~
Referring to Figures 2 and 3,
hacksaws 18 are slidably mounted he-tween
hacksaw support plates 72. Each hacksaw 18 comprises
a base portion 96 Erom which extends a bow por-tion
98 and a hacksaw blade 100 extending be-tween the base
portion 96 and a bow por-tion 98. The base portion
96 defines two horizontal flanges 96a, slidably supported
on the upper edges of hacksaw support plates 72. Base
portion 96 also defines a guide portion 96b, depending
downwardly from flanges 96a between hacksaw support
plates 72. Guide portion 96b may define holes 96c
whereby material may be saved without loss of structural
strength or stiffness. Base portion 96 defines a working
or forward side of hacksaw 18, adjacent work piece 22.
Base portion 96 also defines two lower horizontal
flanges 96f, adapted to fit beneath lower edges of
plates 72.
Extending forwardly from the bo-ttom of base
portion 96 is extension arm 102. Depending downwardly
from a forward end of arm 102 is hydraulic cylinder
mount 104. It will be appreciated that because extension
arms 102 extend away from -the working edge of hacksaws
18, in the event'that a small diameter work piece 22 is
being cut (in other words, the working edges of hacksaws ;~
18 are close together),~arms 102 of each hacksaw 18
might interfere with each other to prevent the proper
: closing of hacksaw blades 18 on work piece 22. In
order to avoid this problem~, extension arms 102 on
opposed:hàcksaws 18 are disposed to one side of each
,
other (see Figure 4). :
B.ase portion 96 further defines a sui-table
~slot means 9~6d adaptable to receive and suppor-t a lower
: - 12 -
: - :
~iS~Z3
end of a hacksaw blade 100. In addi-tion, base portion
96 may also define a generally verkical slot 96e in
communication with slot means 96d, whereby blade 100
may be supported in a generally vertical position.
Extending upwardly from the rear of base
portion 96 is a bow portion 98. Bow portion 98 comprises
an inverted generally L-shaped member, conveniently
having an H-shaped cross section, A forward portion
of bow 98 defines a blade seating portion
98a, vertically aligned with slots 96d and 96e. Blade
seating portion 98a defines a vertical slot 98b. The
upper part of blade seating portion 98a defines a cylin-
drical concave surface 98c.
Referring to Figures 3 and 5,
blade holder 106 is adapted to se~t on a
blade seating portion 98a. For this purpose/ blade
holder 106 defines a cylindrical convex surface 106a
adapted to cooperate with concave surface 98c. A vertical
hole 106b is defined in blade holder 106. Furthermore
blade holder 106 defines a vertical slot 106c extending
into communication with hole 106b from convex surface
106a. Fitted wl-thin hole 106b is a blade mount member
108. A-t ltS lower end, disposed within slot 106c,
blade mount member 108 defines a blade receiving stud
108a. Blade mount member 108 further defines a-t its
upper end disposed at leas~t partially above blade holder
106 a transverse aperture 108b. Wedge 110 is fitted
:
within transverse aperture 108b and is adapted to wedge
blade mount member 108 upwardly relative to blade holder
106. ` ~ ~ ~
~A known hacksaw blade 100 defining a hole
: '' ' :
-13~
lOOa at an upper end and a transverse cross piece
lOOb a-t a lower end is suppor-ted between bow 98 and
base 96. Particularly, blade receiving stud 108a passes
through hole lOOa and cross piece lOOb is fi-tted wi-thin
slot 96d. Blade lO0 is thus oriented essentially
vertically through slots 96e, 98b and 106c.
The above described blade mounting arrangement
is well known and has been described only in order
to facilitate unders-tanding of one embodimen-t of the
invention. It will be appreciated that other
blade mounting arrangements may be used without departing
from the spiri-t and scope of the invention.
In order to slide hacksaws 18 along hacksaw
support plates 72, hydraulic cylinders 112 haviny operating
rods 113 are mounted between hanger members 68 and
hydrauli~ cylinder mounts 104.
In order to securely hold work piece 22
to table 14, a table clamp 24 is provided. Referring
to Figure 8" clamp 24 comprises a rotatable shaft
~0 120 to which is attached a clamping arm 122. Shaft
120 extends downwardly through a hole 124 in table ;~
14 into a hydraulic cylinder 126. An upper annular
chamber 128 is defined be-tween shaft lZ0 and cylinder
126. Similarly, a lower annular chamber 130 is also
defined between shaft 120 and cylinder 126. Upper
and lower~chambers 123 and 130 are separated by suitable
pis-ton/sealing means 132.
The upper end of cylinder 126 is affixed
to seatlng~member~ 134,~ whlch ln turn is affixed (in
the illustrated~embodiment by means of bolts 136) ~o
:~ .
- 14 -
.
~.
table 14. A lower end of cylinder 126 is threaded
to sleeve 138. Shaft 120 extends through sleeve 138
into the interior of a tube 140. The upper end of
tube 140 is also -threaded or otherwise connected -to
sleeve 138.Extendi~g radially outwardly from
the bottom of shaft 120 is pin 142. Pin 142 extends
into a curved or angled slot 144 defined in the walls of
tube 140. Slot 144 ex-tends both longitudinally
along and around at least a portion of, and preferably
about 90 around, the circumference of -tube 140. The
lower end of curved slot 144 joins with the upper
end of a longitudinal slot 146 extending downwardly
along the side of tube 140.
Upper annular chamber 128 communicates
with the outside of seating member 134 by means of
a bore hole 148 defined in seating member 134. Similarly,
lower annular chamber 130 communica-tes with -the outside
of sleeve 138 by means of a bore hole 150 defined
in sleeve 138.
Chambers 128 and 130 are sealed adjacent an
upper and a lower end, respectively, against
shaft 120 by suitable seal means, indicated generally
as 151.
A lower limit switch means, indicated
schematically as 2~0, may be attached to shaft 120.
A suitable arm or portion (not shown) of reciproca-ting
apparatus 20 may extend therefrom, whereby lower limit
switch 240 may be contacted during the downstroke
of assembly 20. It will be appreciated that physical
contact may not be necessary, and that any position
transducer operable to deliver a signal corresponding
to the lowermost position of apparatus 20 in its downstroke
may be used. Attachment oP lower limit switch means 2~0
-15-
- ;
to shaft 120 renders i-t movable relative to work piece
22, for reasons to be discussed.
Alternatively, a fixed lower limit swltch
means may be used.
Similarly, a fixed upper limit switch means,
indicated schema,tically as 242, may be fixed relative to
frame 12, table 14, and cylinder 126.
Referring to Figure 9, a hydraulic operating
system to control the operation of the hacksaw apparatus
10 is illustrated. A two directional pump 160 is
driven by motor M to provlde a source of high pressure
hydraulic fluid. The output of the pump 160 is controlled
by a regulating valve 162. The positioning of a regulat-
ing valve 162 is con-trolled by a suitable elec-trical
or electronic control means indicated generally as
164. A control signal may be inputted to the electronic
control means 164 directly from a control device such
as a computer or a manually pre-set resistor bank
(no-t shown).
~0 In one direction, the output of pump 160
is delivered to manifold 166 which is connected
to manifold ehambers ~6 in eross members 30, and
annular ehamber 6Ob in hydraulie eylinder 58.
~ In the other direction, the output of
pump 160 is direeted to manifold 168 whieh is
eonneeted to tubes 48 and annular ehambers 60a ln
hydraulie eyllnders 58.
Pump 160i maniEolds 166 and 168 and eylinder
58 eomprise a elosed loop system. However, in the
event that some hydraulic fluid leaks out of the closed
loop system, manifolds 166 and 168 are eonneeted via
- 16 -
- ~
" , "
23
check valves 170 and 172, respectively,to a loop charger
pump 174, which is driven by rnotor M. Check valves
170 and 172 are selected or pre-set whereb~ in -the
event -tha-t -the pressure in manifold 166 or 168 drops
(as in the case of a loss of hydraulic fluid), valve
170 or 172,respectively, will operate to allow oil
to flow from pump 174 into the manifold 166 or 168,
as the case may be.
Manifolds 166 and 168 connect -to hydraulic
lines 176 and 178,respectively. Lines 176 and 178
after passing -through regulating valves as described
below, lead to the hacksaw hydraulic cylinders 112.
After leaving manifolds 166 and 168, lines
176 and 178, respectively, pass through a normally-
open, four-way solenoid operating valve 180. In the
normally open position, operating valve 180 allows
hydraulic fluid in lines 176 and 178 to flow unhindered
therethrough. However, in the event that valve 180
is closed, perhaps by operation of a solenoid, lines
176 and 178 are obstructed and fluid may no longer
flow.
After leaving valve 180, line 176 passes
through a blade pressure setting regulating valve, indicated
generally as 182 to line 177. An electrical signal,corresponding
,:.,
; to the proper blade pressure for cut-tiny a particular
material under the desired conditions, delivered from ~
;~ a computer~ or manually;pre-set resistor banks ~'
(not shown) controls the positioning of valve 182. A
pressure transducer means 184 provides feedback on
.
.
23
-the actual pressure in line 177. Valve 182 is operable
whereby when the desired pressure has been achieved
in line 177,valve 182 will close. A by-pass check
valve 186 is provided around blade pressure valve
182, operable to allow fluid to flow from cylinders
112 back around yalve 182.
After leaving operating valve 180, line
178 leads to metering check valve 188. Check valve 188
includes a valve body 188a, defining two chambers
188b and 188c separated by a slideable piston 188d.
Chamber 188b is connected -to line 178. The other
chamber 188c is connected to outlet line 179 through
valve seat 188e. Piston 188d defines a valve gate
188f, adaptable to seal and unseal against seat 188e,
thereby opening and closing outlet line 179 to fluid
flow. A check valve means 188g is provided whereby
fluid may flow from outlet line 179 to line
178. A suitable biasing means, such as spring 188i,
urges piston 188d into a pre-determined position mini-
mizing the volume of chamber 188b and maximizing that
of chamber 188c. An adjustment means, such as screw
188h, is provided to adjust such minimum and ma~imum
volumes.
Lines 179 and 177 also connect to the output
of a~normally-closed, si~-way solenoid manual setting
valve 196. Manual setting valve 196 is part of a
hacksaw utillty hydraulic system which is used to
operate accessory devices which provide for the convenient
operation of~t~he hacksaw apparatus 10. Loop charger
pump 174 may be used to operate such utility system.
.
: :
- 18 -
:
, :
~ ,, , ,, , , .. ". , " , . . : :
S~3
This u-ility system may include, for e~ample, the
manual setting valve 196, the hydraulic cylinder 126
of clamp 24, a table brake 198, forward feed hydraulic
cylinder 200 and perhaps a vice hydra~lic cylinder
202. Each of manual setting valves 196, clamp cylinder
126, vice cylinder 202, forward feed cylinder 200
and table brake 198 are operated independently of
each other.
Theoutput of loop charger pump 174 passes
through a filter 204 into a utility manifold 206.
Utility manifold 206 is provided with a relief valve
208 operable to allow fluid to escape from manifold
206 in the event that -the pressure in manifold 206
becomes too high.
Manual set up line 210 leads from manifold
206 to the input of manual set-ting valve 196. Manual
setting 196 is interlocked with operating valve 180.
Thus, only one oE either valves 196 or 180 may be
in an open position at any one given time. The other
valve 196 or 180 is closed. In an open position,manual
setting valve 196 is operable to allow line 210 to
communicate either with line 177 or with line 179.
The other line 177 or 179 is open to a drain 216.
Clamp line 212 leads from manifold 206 to
clamp operating valve 214. Clamp valve 214 is a
four-way solenold valve whereby line 212 may communicate ~
with elther side of piston seal 132 wlthin cylinder -
126. Simultaneously, the other side of piston seal
132 is open to a drain 216.
:.
3n Similarly, a forward feed line 218 leads
~ 26~.3
from manifold 206 to forward feed operatiny valve 220,
a four-way solenoid valve. Also a vice line 222 leads
from manifold 206 to vice operating valve 224, a four-
way solenoid valve. Both forward feed cylinder 200
and vice cylinder 202 are connected to their respective
operating valves,220 and 224 in fashion similar to that
in which clamp cylinder 126 connects to clamp operating
valve 214.
Forward feed cylinder 200 is connected to
a workpiece forward feed apparatus (not shown) and is
operable to power same. Vice cylinder 202 is connected
to a workpiece vice (not shown) in the forward feed
apparatus for holding or clamping the workpice.
A table brake line 226 connects to table brake
operating valve 228. Line 226a from valve 228 connects
to a hydraulic table brake 198 on the forward feed
apparatus (not shown). Brake 198 includes a piston
198a slidable within cylinder 198b. A suitable biasing
means, such as spring 198c, urges piston 198a outwardly
~0 where it may clamp against a forward feed table (not
shown). A chamber 198d is defined between piston 198a
and cylinder 198b, whereby pressurlzation of chamber
198d tends to urge piston 198a lnwardly~ thus releasing
it from the table and allowing the forward feed table to
be moved.
In operation, a work piece 22 of a particular
material is selected. Hacksaw blades 100 are selected
accordingly. The transverse~cross pieces lOOb of
hacksaw blades 100 are inserted ln slots 96d of base
portions 96. The blade receiving stud 108a of blade
:
;~ -20~
... , .. . _ . . . .
~2~ 23
mount member 108 is passe~ through hole 100a of hacksaw
blades 100. slade holder 106 is then seated on concave
surface 98c of bow por-tion 98. Wedge 110 is then
passed through -transverse aperture 108b of blade mount
member 108 and tapped in-to place so that blade 100
is tightly held in place.
Motor M is turned on -to operate loop charger
pump 174, thus pressurizing utility manifold 206 and
manual set up line 210. Manual se-tting valve 196
is opened, whereby high pressure fluid enters line
179 and flows to hacksaw cylinders 112. Cylinders
112 operate to move hacksaws 18 away from each other.
Work piece 22 is then placed between hacksaw bla~es
18. Because manual setting valve 196 is interlocked
with operating valve 180, operating valve 180 is closed
and no fluid may flow therethrough. Excess fluid
in line 177 returns to valve 196 and to drain 216
through valve 196.
Work piece 22 is positioned on table 14 so
that hacksaws 18 are lined up in order to make the
desired cut. The four-way solenoid clamp operating valve
214 ls operated to close clamp 24 on work piece 22, as
described below. Manual se-tting valve 196 is moved to ~;
its alternate open position, whereby high pressure
:~ fluid~:enters line 177 and flows to hacksaw cylinders -~
112. Cylinders 112 operate to move hacksaws 18 toward -~
each other,~ until they are adjacent or con-tact work
piece 22. Excess fluld ln line 179 returns to valve
196 and to drain 216. Operating valve 180 remains
closed.
~: :
, :
~ -21-
~ Ei5~3
The desired blade pressure, according to
-the ma-terial of work piece 22, the speed of operation
of the hacksaw blades, the -type of hacksaw blade,
lubricant used and other factors, is pre-selec-ted
and entered eithe~r into the controlliny computer or
manual].y operated resistor banks (not shown).
Manual setting valve 196 is then closed,
and simultaneously because of the interlock, operating
valve 180 is opened. Excess fluid in line 179 flows
through check valve 188g and operating valve 180 to
manifold 168.
Motor M is operated to drive hydraulic pump 160,
first pressurizing manifold 166. The pressurization
of manifold 166 causes hydraulic fluid to pass into
line 176 through operating valve 180 to blade pressure
setting or regulating valve 182. As fluid flows through
valve 182 into lines 1.77 and hydraulic cylinders 112,
the pressure therein increases. Hacksaws 18 are forced
by hydraulic cylinder 112 to close in opposed fashion
on opposite sides of work piece 22. Blades 100 contact
work piece 22 either at its original uncut surface
or at the bottom of a previously made cut. As hydraulic
fluid attempts to flow into lines 177 through valve
182, the pressure in lines 177 and hydraulic cylinder 112
increases, thus increasing the pressure of blaaes 100
against work piece 22. The pressure is monitored by -
pressure transducer 184, operable to deliver a mechanical
force corresponding to the pressure to valve 182. Such
force tends to open valve 182. Meanwhile, an electrical
signal from the controlling computer or resistor bank
:'
~22-
~iS~3
(not shown) is delivered to a modulating coil in valve
182. Such signal tends to alose valve 182. The voltage
of this electrical signal corresponds to the desired
blade pressure. Such voltage is sufficient to ensure
that valve 182 remains closed when the actual pressure
equals or is greater than the desired pressure. However,
in the event that the actual pressure drops below the
desired pressure, transducer 184 delivers force to
valve 182 sufficient to open it against the force o~
the modulating coil. While valve 182 is open, more
pressurized fluid can be delivered to cylinders 112 to
increase the actual pressure to the desired pressure.
~t the desired pressure, the modulating coil operates
to close the valve 182 again. When valve 182 is closed
the hydraulic fluid in lines 177 and cylinders 112 is
trapped and the pressure therein remains at the constant
desired blade pressure.
It will be appreciated that other
pressure transducers may be used in any suitable
feedback control system for controlling the operation
of valve 182.
Simultaneously, as the blades close upon
the work piece,manifold 166 delivers high pressure
hydraulic fluid to tubes 48 lying within rods 32.
Such hydraulic fluid passes to maniEold chamber 46
through apertures 44 into annular chamber 50 to bore
holes 52, passing therethrough to lower annular chamber
60b. The hydraulic fluid applies pressure to seals
,
` 62 and 64 thereby causing the cylinders 58, reciprocating
mechanism 20 and hacksaws 18 to move downwardly.
-23-
,
The cutting operation of the hacksaws 100 thus occurs
during the downs-troke.
Hydraulic cylinder 58 continues downwardly
until a lower limit swi-tch means 2~0 is contacted.
Low~r limi-t swi-~ch 240 delivers a signal to the computer
or resistor bank (not shown) which in turn will deliver
a new signal to electronic con-trol means 164 and regulating
valve 162. Regulating valve 162 then causes the output
of pump 160 to be directed to manifold 168.
High pressure fluid is then directed in-to
line 178 and through operating valve 180 to chamber
1~8b of metering check valve 188. Pressurized fluid
tends to close check valve 188g and ~o push piston
188d, whereby the contents of chamber 188c are pressurized
and forced out into line ~79
High pressure fluid passes from metering
check valve 188 through line 179 to hacksaw hydraulic
cylinders 112. High pressure fluid enters hydraulic
cylinders 112 and causes hacksaws 18 to move away f~om
work piece 22. Because the volume of chamber 188c is
limited to a pre-determined amount, i.e., before valve
gate 188f seals against valve seat 188e, hacksaws 18
only move away from work piece 22 a limited, pre-determined
distance.~ The pre-determined volume of chamber 188c
may be adjusted and calibrated by moving adjus~ment s ~~ _
,:
screw 188h a pre-determined distance against moving piston
188d. Excess hydraulic fluid in line 177 is able
to pass around blade pressure setting regulating~valve
182 through check valve 186. Such excess hydraulic
,
fluid is forced from llne 177 into line 176 and into
manlfold 166 through operating valve 180
-24-
~2~ 2~
High pressure fluid passes from manifold
168 into and up tubes 48 -to boreholes 56, passing
therethrough to upper annular chambers 60b. ~ligh
pressure fluid acts on seals 62 and 64, thereby causing
cylinder 58, reciprocating appara-tus 20 and hacksaws
18 to move upwardly. Thus, during the upstroke, little
or no pressure is applied to the work piece 22.
As described above, it can be seen that
pressures are applied by hacksaws 18 to work piece
22 only during the downstroke. During the upstroke
the pressure on -the blades 100 is released and in
fact the blades ]00 may be moved away from work piece
22.
Cylinder 58 continues upwardly until an
upper limit switch means 242 is contacted. Because
lower limit switch means 240 is mounted to clamp 24,
it can be assured that hacksaw blades 100 are used
along their entire working length. In other words,
if a work piece 22 of smaller height is used, clamp
24 will be in lower position -than in the case of a
higher work piece. Because of the lower posi-tion,
limit switch means 240 will also be at a lower position.
Consequently, cylinder 58, reciprocating appara-tus
20 and hacksaws 18 will have to travel a farther downward
dis-tance to contact limit switch means 240.
In the event that hydraulic fluid leaks
from manifolds 166 or 168 or llnes 176 or 178, loop
charger pump 174 will deliver replacement fluid through
check valve 170 or~172, as may be required.
~ Loop~charger pump 174 may also provide high -
-25-
;:; : :
~S~3
pressure hydraulic fluid for use in the accessories
or u-tilit~ system of the hacksaw apparatus 10. In
particular, wi-th appropria-te valves, pump 174 will
provide high pressure hydraulic fluid to clamp cylinder
126, vice hydraulic cylinder 202, forward feed hydraulic
cylinder 200 and -table brake 198 as well as to manual
setting valve 196. Pump 174 delivers pressurized fluid
. .
through filter 204 (where particulates may be
removed from the fluid) into uitility manifold 206.
Utility manifold 206 is provided with a relief valve
208. If the pressure in manifold 206 becomes greater
than a pre-determined maximum pressure, then relief
valve 208 may operate to allow fluid to drain from
manifold 206, thereby reducing the pressure therein
below an acceptable level.
Manlfold 206 also connects to clamp line
212 leading to clamp operating valve 214. Pressurized
fluid may be directed by valve 214 into either line
212a or line 212b, the other line 212b or 212a (not
receiving the pressurized fluid) being open to drain
216. Such pressùrized fluid may be used to operate
clamp 24 . Line 2,12a connects to sleeve 138 in communi-
cation with bore hole 150. Consequently, if clamp valve
214 is moved to one particular position, fluid is pressur- ~'
ized in line 212a and bore hole 150. High pressure fluid may
therefore be introduced through bore hole 150 into
lower annular chamber 130. The hlgh pressure fluid
acts upon plston/seal 132 thereby causing shaft 120
and clamping arm 122 to move upwardly, away from work
piece 22. ~In~this position pin 142 is at a maximum
26-
~o~
upward posi-tion wi-thin slot 144, and prevents further
upward movemen-t of shaf-t 120 and arm 122~
When it is desired to clarnp the work piece 22,
clamp valve 214 is moved -to its other position, thereby
introducing a high pressure fluid -through line 212b
and bore hole 148 to upper annular chamber 128. The
high pressure fluid acts downwardly against piston
seal 132, thereby causing shaft 120 and arm 122 to
move downwardly. Excess fluid in lower annular chamber
~ ... . .
130 passes through bore hole 152, line 212a
and valve 214 to drain 216. As shaft 120 moves downward
pin 142 is constrained to move within slot 144. Thus,
as shaft 120 moves downwardly, pin 142 not only moves
downwaL^dly but also circumferentially thereby causing
shaft 120 and arm 122 to rotate. Slot 144 is defined
such that shaft 120 and arm 122 only rotate about
90. In such position, arm 122 is positioned transversely
across work piece 22. As shaft 120 continues to move
downwardly, pin 142 becomes constrained to move within
longitudinal slot 146. Therefore, shaft 120 and arm
122 may move downwardly without additlonal rota-tion, ;~
until arm 122 contacts work piece 22S
The pressure exerted by arm 122 against work piece
22 counterbalances -the pressure exerted by the hydraulic
fluid against piston seal 132.
Similarly, manifold 206 connects to vice
line 222 whlch connects to vice operating valve 224.
Lines leading from valve 224 to vice hydraulic cylinder
202 prov1de for operation of a vice (not shown) similar
to that of~clamp~ 24.
,
.
, ~ ',
~2~S~
Similarly, a forward feed operating valve 220
may be operated to move the work piece relative to the
hacksaws 18 in either direction as required for additional
hacksaw cutting operations. High pressure fluid leaves
manifold 206 and enters line 218. Fluid from line 218
passes through forward feed operating valve 220 and
passes to forward feed hydraulic cylinder 200. Operation
of the forward feed hydraulic cylinder 200 is identical
to that of hydraulic cylinder 126 and vice hydraulic
cylinder 202.
Additionally, utility manifold 206 connects
to table brake line 226 and delivers high pressure
hydraulic fluid there-through to table brake valve
228. Normally, valve 228 is closed to high pressure
fluid flowing from manifold 206. However, in the
event that the brake 198 must be released, valve 228
may be opened to allow high pressure fluid to flow
into table brake 198. High pressure fluid causes
the piston 198 of brake I98 to retract, thus releasing
the brake.
It will be appreciated that because manual
setting valve 196 and operating valve 180 are interlocked
with each other hlgh pressure fluid may be delivered
to hacksaw cylinders 112 either through the one valve
196 or the other valve 180. It is not possible for
both valves~to deliver high pressure fluid to the
hacksaw c~linders 112 at the same time.
The foregoing is a description of a preferred
embodiment of the~invention which lS glven here by ;
way of example;only. The invention is not to be
`: :
6S(1~3
taken as limited to any of the specific features as
described, bu-t comprehends all such variations thereof
as come within the scope of the appended claims.
,
: ~ :
, ~ ~
.~ 30
~ 29-
:-- : : :
`......... : ~ ~
