Патент USA US2021736

Nov. 19, 1935.
F. MAY
PRUNING DEVICE
Filed Dec. 10, 1954
I
2,021,736
Patented Nov. 19, 1935
2,021,736
A
UNITED STATES PATENT OFFICE
2,021,736
PRUNING DEVICE
' Friedrich May, Magdeburg, Germany
Application December 10, 1934, Serial No. 756,762
In Germany August 30, 1933
4 Claims. (CI. 30—11)
branches by means of knives connected with one
tween this lever and the lever I2 is effected by
means of a saw-blade l8 ,so'that the implement
another and operated by the intermediary of
can be used also for sawing purposes.
This invention relates to a device for pruning
levers subjected in one direction to the action
5 of springs by means of which they are moved
back, together with the knives, into their posi
tion of rest. My present improved pruning de
vice is distinguished from the known devices for
the purpose in view by the characterizing fea
10 tures that one of the two ?at knives, or knife
blades respectively, forming parts of the imple
ment and being shiftable relatively to one an
other is coupled with a one-armed lever, where
as the other blade is coupled with a double-armed
15 lever, preferably in such a manner that the blades
can be adjusted at said levers.
Designing the pruning device in this manner
renders it possible to manufacture it on the
whole-sale scale at a low price, and further ad
20 vantages are that this improved device is very
reliable in service and operates unobjectionably
and without jamming even if the blades are not
held exactly at right angles with respect to the
branches to be lopped-off.
25
In a preferred constructional form of this de
vice the two levers mentioned are connected with
one another by a serrated bar, or a saw blade
respectively, may be in connection with a spring
actuated member able to take up the recoils.
30
The invention is illustrated diagrammatically
and by way of example on the accompanying
drawing which shows a side-view of a pruning
device designed according to this invention.
On the drawing, I and 2 are the two knife
3
blades which are arranged above one another and
of which I is shiftable between guide members
3 and 4 forming parts of a rigid frame 5, where
as the blade 2 is shiftable between said guide
member and a guide member 1 having a guide
40 groove 6 and being preferably detachably at
tached to said frame 5. The blade 1 is coupled
with a one-armed lever l2 fulcrumed at H to
the guide member 3. In said lever is a slot l0
and in said blade is a slot 8, and a bolt 9 though
45 both slots can be adjusted in the slot 8 and secured
therein after the adjustment. The bolt slides
in the slot 5E3 when the lever I2 is moved up and
down in order to actuate the blade I. Likewise
the blade 2 is coupled with a double-armed lever '
50
ll fulcrumed at iii to the frame 5; it has a slot
l3 and said lever has a slot l5, and a bolt l4 ex
tends through both these slots. The bolt I4 can
be adjusted and ?xed in its adjusted position in
55
the same manner as the bolt 9 which will be clear
without a more detailed explanation.
The two blades can be moved simultaneously,
counter to one another, by means of a rope 20 or
the like. In the preferred constructional form
shown by way of example, the rope 20 terminates
already at the lever I1 and the connection be
Drawing the levers back into their position of
rest can be effected, for instance, either by means 5
of a helical tensile spring 2| engaging the lever
l2 or by means of a helical tensile spring 22 en
gaging the lever l‘! or by both these springs, as in
the drawing. It is suited to the sawing purpose
to insert between the blade l8 and the lever 12 a 10
rec-oil device H), as in the ?gure shown.
23 and 24 are abutment members for the two
levers, and 2'1 is a wooden rod, to the upper end
of which the implement is attached. The lower
portion of this latter is tubular, as at 26, and 15
receives in it the correspondingly shaped upper
end of said rod. Below the guide member I the
frame 5 is provided with a hook 25 serving for
tearing down branches that have not been com
pletely severed off by the knife blades.
20
I claim:
1. A branch pruning device, comprising, in com
bination, two oppositely located knife blades mov
able in opposite directions, means guiding said
blades, a one-armed lever coupled with one of the 25
blades and a double-armed lever coupled with
the other blade, means for moving said levers with
the blades back into their original position, and
means for operating the said levers and the said
blades.
30
2. A branch pruning device, comprising, in com
bination, two oppositely located knife blades mov
able in opposite directions and subjected to the
action of springs adapted to move them into their
original position, means guiding said blades, a 35
one-armed lever coupled with one of said blades
and a double-armed lever coupled with the other
blade, and means for actuating said levers to
gether with the said blades.
,
3. A branch pruning device, comprising, in com~ 4O
bination, two knife blades arranged oppositely to
one another, guide members for said blades, 2. one
armed lever coupled with one of said blades and a
double-armed lever coupled with the other blade,
a saw-blade connecting the two levers with one 45
another at their free ends, a pulling member at
tached to one of said levers; and means adapted
to counter-act said pulling member.
4. A branch pruning device, comprising, in com
bination, a frame having pairs of guides located 50
one above the other, knife blades shiftable in said
guides in opposite directions, a one-armed lever
fulcrumed in said frame and coupled with one
of said blades, a double-armed lever likewise ful
crumed in said frame and coupled with the other 55
blade, springs adapted to move said levers back
into their initial position, and means for operat
ing the said levers with the blades from below.
FRIEDRICH MAY.