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Патент USA US3041735

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July 3, 1962
F. B. HARRIES
3,041,725
HYDRAULIC CUTTING IMPLEMENT
Filed April 25, 1961
Inventor
FRANCIS BERNARD HARRIES
Allorney
v United States Patent Office
1
3,041,725
Francis B. Harries, Dirlrchinburg, P.O. Melmoth,
HYDRAULIC CUTTING HVIPLEMENT
Zululand, Union of South Africa
_ Filed Apr. 25, 1961, Ser. No. 105,334
Claims priority, application Union of South Africa
May 2, 1960
11 Claims. (Cl. 30—180)
3,041,725
Patented July 3, 1962
2.
tube. The extension guide may be an extension tube
and the engaging means may comprise a bayonet type
of ?tting between guide and extension tube, and the at
tachment means may comprise a male screw thread for
engaging with a female thread in the handle coaxially
with the master cylinder tube, the handle having a cross
sectional shape to engage slidably with the extension tube
bore.
Further features will become apparent from the follow
This invention relates to hydraulic cutting implements 10 ing description of a speci?c embodiment of the inven
suitable for use in pruning.
According to the invention a pruning and cutting im
plement comprises a cutting head having a cutting blade,
tion with reference to the accompanying drawings.
-
in the drawings:
7
FIGURE 1 shows a part sectional side elevation of the
an anvil for cooperating with the cutting blade and slid
head end of an implement.
ably mounted on the head, a slave hydraulic cylinder 15
FIGURE 2 shows a part sectional side elevation of the
fast with the cutting head, a slave plunger within the
handle'end of an implement;
hydraulic cylinder and cooperating therewith and fast
FIGURE 3 shows a part underside plan view of the.
with the anvil, bias means to bias the anvil to an initial
implement and corresponding to FIGURE 1; and
position away from the cutting blade, a master hydraulic
cylinder hydraulically connected to and of lesser cross
sectional area than the slave hydraulic cylinder, a master
plunger within the master hydraulic cylinder for coop
erating therewith and having a volumetric displacement
modi?cation of the implement.
Referring to the drawings reference numeral 10 refers
generally to a cutting head of general hatchet shape and
in the master cylinder of the same order as the 'volu
de?ning an acute angle with a stem 16 on which is slid
FIGURE 4 shows a part sectional side elevation of a
having a transverse part 12 having a cutting blade 14
metric displacement of the slave plunger within the slave 25 ably mounted an anvil 18 having a face 20 for coopera
hydraulic cylinder, whereby hydraulic ?uid in the master
tion with cutting blade 14. On either side of the face
cylinder is displaceable by the master plunger into the
20 there is provided a wing edge 21‘ forming a pair of
slave cylinder to displace the slave plunger and anvil
diverging wing edges.
against the action of the bias means towards a ?nal cut
Fast ‘with cutting head 19 there is provided a stop 22
ting position wherein the cutting edge of the head is
which is adapted to cooperate with shoulder '24 on the
close to the anvil and wherein it performs a cutting action
anvil to limit the ?nal position of the anvil to prevent
in cooperation with the anvil.
.
the cutting edge 14 bedding into the face 2i)‘ of the anvil
The invention may include one or more of the fol—
during cutting. The anvil has side walls 26 de?ning a
lowing features.
passage through which stem 16 is adapted'to pass slid
The master cylinder may comprise a tube-having a
‘ably. The anvil is attached via slave plunger rod 28
handle at one end and a sealing gland at the other, and
to slave plunger 30' axially displaceable within slave cyl
the hydraulic connection between slave and master cyl
inder 32 attached Via stirrups 34 to‘ stem 16 of cutting
inders may comprise a small bore tube passing through
head 10. The slave plunger 3% and hence anvil 18 are
the sealing gland coaxial with the master cylinder and
biassed towards an initial position wherein anvil face
connected to the master plunger to provide a hydraulic 40 20 and cutting blade 14 are apart, by means of helical
connection between slave cylinder and that side of the
spring 36.
master cylinder remote from the sealing gland. A guide
The chamber 38 of slave cylinder 32 is in connection
may be provided fast with the cutting head for de?ning a
via tube 40‘ and small bore tube 42 with chamber 44
linear pathway for the tube in a direction parallel to the
inside tube‘ 46 comprising the master cylinder. Handle
tube axis. The guide may be a guide tube coaxial with 45 cum ?ller plug 48 screws into the end 50 of tube 46,
the master cylinder tube;
remote from the cutting head 10. The near end 52 of
There may be provided an anvil stop on the cutting
tube 46 has running gland 54 adapted to coact slidably
head, and a shoulder on the ‘anvil to cooperate therewith
and sealingly with small ‘bore tube 4-2, which is coaxial
to limit the ?nal position of the anvil to prevent the cut
with tube 46. In side tube 46 there is provided master
ting edge cutting into the anvil. The anvil may have fast
plunger 56 connected to small bore tube 42.
with it a pair of diverging wing edges spaced laterally
Fast with the slave cylinder 32 and coaxial with tube
one on either side of ‘the anvil and of the cutting edge.
46 there is provided guide tube 58 having a ring guide 60
The cutting head may be of hatchet shape and may
to receive tube 46 axially slidable within it.
comprise a stem on which takes place the slidable mount
By way of development there may be provided an ex
55
ing of the anvil, and a transverse limb having the cutting
tension guide tube 62 adapted to cooperate bayonet fash
edge disposed at an acute angle to the stem.
ion with lugs 64 provided fast with guide tube 58. There
The cross-sectional area of the master plunger may no
is further provided extension rod 66 adapted to screw
a fraction of that of the slave plunger, say about one
into the screw threaded socket 68 of handle 48, and
tenth to one twentieth, and the master and slave cylin
slidable in ring guide 70 in the end of guide tube 62.
ders may conveniently be coaxial.
60 To the end of rod 66 there is screwed hand grip 72.
The handle may screw into one end of the bore of the
The bore of extension tube 62 and the cross-sectional
tube and coaxially with it, the opening at the end of the
shape of handle 48 are such that handle 48 is easily slid
tube forming a ?ller opening and the handle forming
able within the bore of extension tube 62.
also a hydraulic fluid ?ller plug for the opening. There
The working stroke of the slave plunger 30 is con
may be provided an extension guide having engaging
veniently of the order of about 2 to 5 cm. and the
means for engaging with the guide to provide an ex
tended linear pathway further from the cutting head and
parallel to the ?rst linear pathway, and a rod cooperat
ing \slidably with the extension guide and having a hand
grip at a remote end projecting beyond the extension
guide and having attachment means at its opposite inner
end for attachment to the handle of the master cylinder
working stroke of the master plunger is conveniently
about 70 em, but may vary from about 20 cm. to about
100 cm. depending upon the ratio required, and the
volumetric displacement of the master plunger in a single
working stroke is su?icient to displace the anvil a full
working stroke. Accordingly the cross-sectional area of
3,041,725
3
4
the master plunger is a fraction of the cross-sectional ‘area
vii has fast with it a pair of diverging wing edges spaced
of the slave plunger.
-
In operation, the cutting head 10 is positioned such
laterally one on either side of the anvil and of the cut
ting edge.
that the branch, twig, or other member to be cut lies
between cutting blade 14 and anvil 18. Thercupon,
4. An implement according to claim 1 in which the cut
ting head is of hatchet shape and comprises a stem on
handle 43 connected to tube 46 is pushed home, running
gland 54 thereby sliding along small bore tube 42 and
plunger 56 being displaced within tube 46, to displace
which takes place the slidable mounting of the anvil,
and a transverse limb having the cutting edge disposed
at an acute angle to‘ the stem.
5. An implement according to claim 1 in which the
hydraulic ?uid in chamber 44» in tube 46 via small bore
tube 42v into chamber 33 of slave cylinder 32. Shoulder 10 cross-sectional area of the master plunger is about one
24 abuts against stop 22 just before cutting edge 14 beds
tenth of one twentieth of the cross-sectional area of the
slave plunger.
into face 20 and leaves slight clearance between face 2i}
6. An implement according to claim 1 in which mas
and cutting blade 14. A single working stroke of the
ter and slave cylinders are coaxial.
master plunger is su?‘icient to cause a full cutting stroke
7. An implement according to claim 1 in which the
of the slave plunger.
15
master cylinder comprises a tube having a handle at one
The wing edges 21 locate the anvil in relation to the
twig being cut and reduces the tendency for the anvil
end and a sealing gland at the other, and in which the
hydraulic connection between slave and master cylinders
to be de?ected by the grain of the wood being cut.
comprises a small bore tube passing through the sealing
When a long reach is necessary, the extension guide
gland and being coaxial with the master cylinder and
tube 62 is attached and the rod 66 screwed in. The
being connected to the master plunger to provide a hy
operation is as before, except that handle 48 is now dis
draulic connection between slave cylinder and that side
placed via hand grip 72.
'
of the master cylinder remote from the sealing gland,
The implement is stored cutting head downward thus
and in which a guide is provided fast with the cutting
ensuring that any air bubbles in the master cylinder will
be at the handle 48 end. The ?uid may be easily re 25 head for de?ning a linear pathway for the tube in a di
rection parallel to the tube axis.
plenished merely by unscrewing handle 48.
I claim:
1. A pruning and cutting implement comprising a cut
ting head having a cutting blade, an anvil for cooperat
ing with the "Cutting blade and slidably mounted on the
head, a slave hydraulic cylinder fast with the cutting
head, a slave plunger within the hydraulic cylinder and
cooperating therewith and fast with the anvil, bias means
to- bias the anvil to an initial position away from the
cutting blade, a master hydraulic cylinder hydraulically 35
connected to and of lesser cross sectional area than the
slave hydraulic cylinder, a master plunger within the
master hydraulic cylinder for cooperating therewith and
having a volumetric displacement in the master cylinder
8. An implement according to‘ claim 7 in which the
guide is a guide tube coaxial with the master cylinder
tube.
9.-An implement according to claim 7 in which the
handle screws into one end of the bore of the tube and
coaxially with it, the opening at the end of the tube
forming a ?ller opening and'the handle forming also a
hydraulic fluid ?ller plug for the opening.
10. An implement according to claim 7, in which there
is provided an extension guide having engaging means
for engaging with the guide to provide an extended linear
pathway further from the cutting head and parallel to
the first linear pathway, and a rod cooperating slidably
of the same order as the volumetric displacement of the 40 with the extension guide and having a hand grip at a
slave plunger within the slave hydraulic cylinder, whereby
hydraulic ?uid in the master cylinder is displaceable by
the master plunger into the slave cylinder to displace the
slave plunger and anvil against the action of the bias
remote end projecting beyond the extension guide and
having attachment means at its opposite inner end for
attachment to the handle of the master cylinder tube.
11. An implement according to claim 10 in which the
means towards a ?nal cutting position wherein the cut
extension guide is an extension tube and in which the
ting blade is close to the anvil and wherein it performs
a cutting action in cooperation with the anvil.
2. An implement according to claim 1 in Which there
is provided an anvil stop on the cutting head, and a
engaging means comprises a bayonet type of ?tting be
tween guide and extension tube, and in which the attach
shoulder on the anvil to cooperate therewith to limit
the ?nal position of the anvil to prevent the cutting edge
cutting into the anvil.
3. An implement according to claim 1 in which the an
ment means comprises a male screw thread for engaging
with a female thread in the handle coaxially with the
master cylinder tube, the handle having a cross~sectional
shape to engage slidably with the extension tube bore.
No references cited.
UNITED STATES» PATENT OFFICE
CERTIFICATE, OF CORRECTION
Patent N0. 3,041,725
July 3Q 1962
Francis B° Harries
It is hereby certified that error appears in the above numbered pat
ent requiring correction and that the said Letters Patent should read as
corrected below.
Column 4, line 11I for "of",
tO
first occurrence,
read
—
-—.
Signed and sealed this 30th day of October 1962»
(SEAL)
Attest:
ERNEST W. SWIDER
Attesting Officer
DAVID L. LADD
Commissioner of Patents
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