U.S. patent application number 15/932264 was filed with the patent office on 2018-07-05 for extendible working machine.
This patent application is currently assigned to TAISEIMONAC CO., LTD.. The applicant listed for this patent is TAISEIMONAC CO., LTD.. Invention is credited to Shigeru Miyakawa.
Application Number | 20180187714 15/932264 |
Document ID | / |
Family ID | 49583699 |
Filed Date | 2018-07-05 |
United States Patent
Application |
20180187714 |
Kind Code |
A1 |
Miyakawa; Shigeru |
July 5, 2018 |
Extendible working machine
Abstract
An extendible working machine has a rotation/drive section, a
working section, and a rod section which connects the
rotation/drive section and the working section, transmits
rotational force to the working section, and can be extended and
retracted. The rod section has a tube body which can be extended
and retracted, and also has a shaft body which extends in the axial
direction within the tube body and which can be extended and
retracted together with the tube body. The shaft body has a pipe
shaft which is supported within the inner tube in a rotatable
manner. Helical grooves are formed in the surface of the drive
shaft. The drive shaft is connected to the pipe shaft so the pipe
shaft can move in the axial direction along the outer surface of
the drive shaft and so the rotation of the drive shaft is
transmitted to the pipe shaft.
Inventors: |
Miyakawa; Shigeru; (Hyogo,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
TAISEIMONAC CO., LTD. |
Osaka |
|
JP |
|
|
Assignee: |
TAISEIMONAC CO., LTD.
Osaka
JP
|
Family ID: |
49583699 |
Appl. No.: |
15/932264 |
Filed: |
February 16, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14401818 |
Nov 17, 2014 |
9897135 |
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PCT/JP2013/063273 |
May 13, 2013 |
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15932264 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A01D 34/90 20130101;
F16C 3/035 20130101; F16C 2322/50 20130101; A01G 3/033 20130101;
F16D 3/06 20130101; A01G 3/085 20130101; F16C 2310/00 20130101 |
International
Class: |
F16C 3/035 20060101
F16C003/035; F16D 3/06 20060101 F16D003/06; A01G 3/033 20060101
A01G003/033; A01D 34/90 20060101 A01D034/90; A01G 3/08 20060101
A01G003/08 |
Foreign Application Data
Date |
Code |
Application Number |
May 18, 2012 |
JP |
2012-115108 |
Claims
1. An extendible working machine comprising: a rotation/drive
section that generates a rotational force; a working section
operated by the rotational force; a extendible rod section having
the rotation/drive section on a proximal end of the rod section and
the working section on a distal end of the rod section, the rod
section transmitting the rotational force of the rotation/drive
section to the working section; and an operation section that
operates an action of the working section, the rod section
including a proximal-end tube having the operation section, an
extendible tube body connected to the proximal-end tube, and a
shaft body that extends in an axial direction of the rod section in
the proximal-end tube and the tube body so as to extend and retract
with the tube body and has the rotation/drive section and the
working section on ends of the shaft body, the tube body including
an outer tube on a proximal side of the tube body and an inner tube
on a distal side of the tube body, the inner tube being movable in
the outer tube in the axial direction of the rod section, the shaft
body including a drive shaft that is rotatably supported by a
plurality of bearings in the outer tube and is connected to the
rotation/drive section, and a pipe shaft that is rotatably
supported in the inner tube and is connected to the working
section, the drive shaft having a plurality of helical grooves on a
surface of the drive shaft, the pipe shaft having a connecting pipe
on a proximal end of the pipe shaft with the drive shaft inserted
into the connecting pipe, the connecting pipe having a plurality of
helical convex portions on an inner surface of the connecting pipe,
the convex portions being movable along the grooves of the drive
shaft on the inner surface of the connecting pipe, allowing the
pipe shaft to move along an outer surface of the drive shaft in the
axial direction, the drive shaft being connected to the pipe shaft
so as to transmit a rotation of the drive shaft to the pipe shaft,
the bearing including a bush holder that is movable relative to the
outer tube in the axial direction and is incapable of rotating in
the outer tube, a drive bush that has helical convex portions on an
inner surface of the drive bush, the convex portions being movable
in the grooves on the surface of the drive shaft, and a bearing
disposed between an inner surface of the bush holder and an outer
surface of the drive bush, allowing the drive shaft to rotate in
the outer tube, the bush holder being fixed to a proximal end of
the outer tube, the bearing being disposed between an outer surface
of a fixed drive bush on the drive shaft and the inner surface of
the bush holder, allowing the drive shaft to be rotatable in the
outer tube and immovable in the axial direction relative to the
outer tube, the bush holder being fixed to a proximal end of the
inner tube, the bearing being disposed between the inner surface of
the bush holder and an outer surface of the connecting pipe,
allowing the pipe shaft to be rotatable in the inner tube and
immovable in the axial direction relative to the inner tube, the
outer tube containing springs disposed between the bearings, the
inner tube moving in the outer tube so as to extend or compress the
springs, the bearings moving in the axial direction so as to extend
and retract the rod section.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 14/401,818 filed Nov. 17, 2014, which is a
U.S. National phase under 35 U.S.C. .sctn. 371 of International
Patent Application Number PCT/JP2013/063273 filed Mar. 13, 2013,
which claims the benefit of priority to Japanese Patent Application
Number 2012-115108 filed May 18, 2012, the contents of which are
incorporated herein by reference in their entirety.
BACKGROUND ART
Technical Field
[0002] The present invention relates to an extendible working
machine usable as, for example, a pole saw for operations at high
elevations.
[0003] A working device conventionally used for trimming branches
at high elevations has a working section of a pole saw, etc. on the
end of an extendible rod section and a drive section on the rear
end of the rod section (See Patent Literatures 1 and 2). Various
kinds of such working devices are available for kinds of
operations. In the structure of such a working device, working
sections and drive sections are optionally selected and replaced on
a rod section according to the kind of operation.
CITATION LIST
Patent Literature
[0004] Patent Literature 1--Japanese Utility Model Registration No.
3123389
[0005] Patent Literature 2--Japanese Patent Laid-Open No.
2009-82028
SUMMARY OF INVENTION
Technical Problem
[0006] Such an extendible working machine used at high elevations
requires an ability to be extended longer, a light weight, and
safety. However, an extended structure with safety may have a thick
and heavy rod section and thus may lead to difficulty in reducing
the weight of the rod section, resulting in deteriorated
workability.
[0007] In order to solve the problem, an object of the present
invention is to provide an extendible working machine which is
lightweight and which has a rod section capable of being extended
longer.
Solution to Problem
[0008] An extendible working machine of the present invention
includes: a rotation/drive section that generates a rotational
force; a working section operated by the rotational force; a
extendible rod section having the rotation/drive section on the
proximal end of the rod section and the working section on the
distal end of the rod section, the rod section transmitting the
rotational force of the rotation/drive section to the working
section; and an operation section that operates an action of the
working section, the rod section including a proximal-end tube
having the operation section, an extendible tube body connected to
the proximal-end tube, and a shaft body that extends in the axial
direction of the rod section in the proximal-end tube and the tube
body so as to extend and retract with the tube body and has the
rotation/drive section and the working section on the ends of the
shaft body, the tube body including an outer tube on the proximal
side of the tube body and an inner tube on the distal side of the
tube body, the inner tube being movable in the outer tube in the
axial direction of the rod section, the shaft body including a
drive shaft that is rotatably supported by a plurality of bearings
in the outer tube and is connected to the rotation/drive section,
and a pipe shaft that is rotatably supported in the inner tube and
is connected to the working section, the drive shaft having a
plurality of helical grooves on the surface of the drive shaft, the
pipe shaft having a connecting pipe on the proximal end of the pipe
shaft with the drive shaft inserted into the connecting pipe, the
connecting pipe having a plurality of helical convex portions on
the inner surface of the connecting pipe, the convex portions being
movable along the grooves of the drive shaft on the inner surface
of the connecting pipe, allowing the pipe shaft to move along the
outer surface of the drive shaft in the axial direction, the drive
shaft being connected to the pipe shaft so as to transmit a
rotation of the drive shaft to the pipe shaft, the bearing
including a bush holder that is movable relative to the outer tube
in the axial direction and is incapable of rotating in the outer
tube, a drive bush that has helical convex portions on the inner
surface of the drive bush, the convex portions being movable in the
grooves on the surface of the drive shaft, and a bearing disposed
between the inner surface of the bush holder and the outer surface
of the drive bush, allowing the drive shaft to rotate in the outer
tube, the bush holder being fixed to the proximal end of the outer
tube, the bearing being disposed between the outer surface of a
fixed drive bush on the drive shaft and the inner surface of the
bush holder, allowing the drive shaft to be rotatable in the outer
tube and immovable in the axial direction relative to the outer
tube, the bush holder being fixed to the proximal end of the inner
tube, the bearing being disposed between the inner surface of the
bush holder and the outer surface of the connecting pipe, allowing
the pipe shaft to be rotatable in the inner tube and immovable in
the axial direction relative to the inner tube, the outer tube
containing springs disposed between the bearings, the inner tube
moving in the outer tube so as to extend or compress the springs,
the bearings moving in the axial direction so as to extend and
retract the rod section.
[0009] The helical grooves on the surface of the drive shaft are
formed by twisting the drive shaft with the grooves linearly formed
in the axial direction.
Advantageous Effects of Invention
[0010] The extendible working machine of the present invention
includes a rotation/drive section that generates a rotational
force, a working section operated by the rotational force, an
extendible rod section having the rotation/drive section on the
proximal end of the rod section and the working section on the
distal end of the rod section connected, the rod section
transmitting the rotational force to the working section, and an
operation section that operates an action of the working section.
The drive shaft having the helical grooves on the surface of the
drive shaft is used for the shaft body of the rod section, allowing
the drive shaft to have a smaller diameter than in the related art.
Thus, the tube body of the rod section can be also reduced in
diameter, reducing the weight of the overall rod section. Moreover,
the tube body reduced in diameter can be easily held by a person
with small hands. This can achieve an extendible working machine
with a light weight and enhanced ease of handling and
operation.
[0011] The helical grooves on the surface of the drive shaft are
formed by twisting the drive shaft with the grooves linearly formed
in the axial direction. Thus, the drive shaft reduced in diameter
can be kept in a linear shape, capable of suppressing vibrations
during a rotation of the drive shaft.
BRIEF DESCRIPTION OF DRAWINGS
[0012] FIG. 1 is a perspective view showing an extendible working
machine according to the present invention.
[0013] FIG. 2 is a schematic cross sectional view showing a rod
section of the retracted extendible working machine in the
longitudinal direction.
[0014] FIG. 3 is a schematic cross sectional view showing the rod
section of the extended extendible working machine in the
longitudinal direction.
[0015] FIG. 4 is a side view of a drive shaft.
[0016] FIG. 5 is a longitudinal sectional view of a pipe shaft.
[0017] FIG. 6 is a cross sectional view of the drive shaft.
[0018] FIG. 7 is a cross sectional view of the pipe shaft.
[0019] FIG. 8 is a cross sectional view at a location where a
bearing and a stopper are disposed.
[0020] FIG. 9 is a longitudinal sectional view at a location where
the bearing and a fixed bearing are disposed.
[0021] FIG. 10 is a longitudinal sectional view at a location where
the stopper is disposed.
[0022] FIG. 11 is a perspective view of a drive bush.
[0023] FIG. 12 is a cross sectional view at a location where the
fixed bearing is disposed.
DESCRIPTION OF EMBODIMENT
[0024] An extendible working machine 1 of the present invention
will be specifically described below in accordance with the
accompanying drawings. FIG. 1 is a perspective view showing the
extendible working machine 1 of the present invention. FIG. 2 is a
schematic cross sectional view showing a rod section 4 of the
retracted extendible working machine 1 in the longitudinal
direction. FIG. 3 is a schematic cross sectional view showing the
rod section 4 of the extended extendible working machine 1 in the
longitudinal direction.
[0025] As shown in FIG. 1, the extendible working machine 1 of the
present invention includes a rotation/drive section 2 that
generates a rotational force, a working section 3 that is driven by
the transmitted rotational force, the extendible rod section 4 that
connects the rotation/drive section 2 on the proximal end of the
rod section 4 and the working section 3 on the distal end of the
rod section 4 so as to transmit the rotational force to the working
section 3, and an operation section 5 that operates an action of
the working section 3. The rod section 4 is extended and retracted
to perform operations at high elevations using the working section
3.
[0026] The rotation/drive section 2 accommodates, for example, a
small engine for generating a rotational force. The working section
3 is, for example, a pruner having pruning shears passing each
other. The working section 3 can be optionally selected according
to an operation. The operation section 5 is designed to operate the
extendible working machine 1 with a structure for turning on or off
the rotation/drive section 2.
[0027] As shown in FIGS. 2 and 3, the rod section 4 includes a
cylindrical proximal-end tube 6 to which the rotation/drive section
2 is connected and the operation section 5 is attached, a tube body
7 that is connected to the proximal-end tube 6 so as to extend and
retract in the axial direction, and a shaft body 8 that extends in
the axial direction in the proximal-end tube 6 and the tube body 7
so as to extend and retract in the axial direction according to
extension and retraction of the tube body 7. The tube body 7 and
the shaft body 8 cooperatively extend and retract so as to allow
extension and retraction of the rod section 4.
[0028] The tube body 7 includes an outer tube 9 on the proximal end
and an inner tube 10 on the distal end. The inside diameter of the
outer tube 9 is larger than the outside diameter of the inner tube
10. The inner tube 9 is inserted into the outer tube 10 so as to
move in the outer tube 10 in the axial direction of the rod section
4. The inner tube 9 is, for example, 24 mm in outside diameter and
1425 mm in length. The outer tube 9 is, for example, 35 mm in
outside diameter and 1694 mm in length. As shown in FIG. 9, the
proximal-end tube 6 is fixed to the proximal end of the outer tube
7 via a pipe joint 26. The proximal end of the inner tube 10 is
opened while the distal end of the inner tube 10 is closed by a lid
having a hole where the end of the shaft body 8 is inserted and
protruded.
[0029] The shaft body 8 includes a drive shaft 11 that is circular
in cross section and is disposed in the outer tube 9 and a pipe
shaft 12 that is annular in cross section and is disposed in the
inner tube 10. The drive shaft 11 is rotatably supported by a
plurality of bearings 18 disposed in the outer tube 9 such that the
drive shaft 11 is rotatable in the outer tube 9. The proximal end
of the drive shaft 11 is connected to the rotation/drive section 2
through the proximal-end tube 6 so as to protrude from the
proximal-end tube 6. The pipe shaft 12 in the inner tube 10 is
rotatable relative to the inner tube 10 and is immovable in the
axial direction. The distal end of the pipe shaft 12 protrudes from
the inner tube 10.
[0030] As shown in FIGS. 4 and 6, three grooves 13 are helically
formed on the surface of the drive shaft 11. The drive shaft 11 is
a steel rod that is twisted after the three grooves 13 are linearly
formed in the axial direction at equal intervals on the surface of
the linear steel rod. If the drive shaft 11 has a small outside
diameter of, for example, 6.5 mm, the coiled steel rod is linearly
extended and then is cut to a predetermined length. However, a
round steel rod shaped like a coil cannot be linearly extended only
by stretching and thus needs to be twisted to be linearly extended.
The helical grooves 13 are formed on the drive shaft 11 by using a
method of helically twisting the linear grooves. This obtains the
linear drive shaft 11 that can eliminate vibrations caused by
shakes during rotations.
[0031] A joint 14 having undergone spline machining is fixed to the
proximal end of the drive shaft 11 by friction welding. The joint
14 protrudes from the proximal-end tube 6 and is connected to the
rotation/drive section 2 by spline fitting. Spline machining
performed on the joint 14 allows spline fitting to the typical
rotation/drive section 2. The rotation/drive section 2 can be
attached in various forms. Instead of spline machining, the joint
14 to be fit and fixed to the rotation/drive section 2 may be
machined into a prismatic shape.
[0032] As shown in FIG. 5, a connecting pipe 15, in which the drive
shaft 11 is inserted and connected, is fixed to the proximal end of
the pipe shaft 12 while a joint 17 having undergone spline
machining is fixed to the distal end of the pipe shaft 12. The
joint 17 protrudes from the search end of the inner tube 10 and is
connected to the typical working section 3 by spline fitting. This
allows attachment of various kinds of the working section 3.
Instead of spline machining, the joint 17 may be machined into a
prismatic shape to be fit and fixed to the working section 3.
[0033] The interior of the connecting pipe 15 has a step between a
large-diameter portion having an inside diameter corresponding to
the outside diameter of the pipe shaft 12 and a small-diameter
portion having an inside diameter corresponding to the outside
diameter of the drive shaft 11. Accordingly, the outer surface of
the connecting pipe 15 also has a step. The proximal end of the
pipe shaft 12 is inserted into the large-diameter portion so as to
be fit and fixed into the large-diameter portion. As shown in FIGS.
5 and 7, three helical convex portions 16 are formed at equal
intervals on the inner surface of the small-diameter portion of the
connecting pipe 15. The convex portions 16 on the inner surface of
the connecting pipe 15 are movable along the grooves 13 of the
drive shaft 11.
[0034] The drive shaft 11 is inserted from the distal end into the
connecting pipe 15 fixed to the pipe shaft 12. At this point, as
shown in FIG. 8, the convex portions 16 of the connecting pipe 15
are located in the grooves 13 of the drive shaft 11. With this
configuration, if the pipe shaft 12 applies a force in the axial
direction during an extension and retraction of the rod section 4,
the convex portions 16 moving in the grooves 13 allow the pipe
shaft 12 to rotatably move in the axial direction along the outer
surface of the drive shaft 11. Subsequently, the rotation/drive
section 2 rotates the drive shaft 11 to operate the working section
3 with the pipe shaft 12 fixed, the engagement between the convex
portions 16 and the grooves 13 transmits the rotation of the drive
shaft 11 to the pipe shaft 12, thereby rotating the pipe shaft
12.
[0035] Thus, the connecting pipe 15 connects the drive shaft 11 and
the pipe shaft 12 such that the pipe shaft 12 is movable in the
axial direction relative to the drive shaft 11 and the rotation of
the drive shaft 11 is transmitted to the pipe shaft 12.
Consequently, the shaft body 8 is extendible and the rotational
force of the rotation/drive section 2 is transmitted to the pipe
shaft 12 via the drive shaft 11 and then is transmitted to the
working section 3 so as to drive the working section 3.
[0036] As shown in FIG. 9, the bearing 18 includes a substantially
cylindrical bush holder 19, a substantially cylindrical drive bush
20 disposed in the bush holder 19, and ball bearings 21 interposed
between the inner surface of the bush holder 19 and the outer
surface of the drive bush 20. The drive bush 20 is disposed so as
to rotate relative to the bush holder 19.
[0037] Four grooves 22 linearly extending in the axial direction
are formed at equal intervals on the outer surface of the bush
holder 19. Furthermore, four convex portions 23 linearly extending
in the axial direction are formed on the inner surface of the outer
tube 9. As shown in FIG. 8, the bush holder 19 is disposed in the
outer tube 9 so as to locate the convex portions 23 in the grooves
22. Thus, the bush holder 19 is disposed in the outer tube 9 so as
to move in the axial direction and not to rotate relative to the
outer tube 9.
[0038] As shown in FIG. 11, three helical convex portions 24 are
formed at equal intervals on the inner surface of the drive bush 20
so as to be able to move along the grooves 13 of the drive shaft
11. With this configuration, the drive bush 20 rotates when moving
in the axial direction relative to the drive shaft 11. When the
drive shaft 11 rotates, the drive bush 20 rotates with the drive
shaft 11. With the bearing 18 configured thus, the drive shaft 11
is rotatably disposed at the center of the outer tube 9 and the
bearing 18 is disposed so as to move in the axial direction in the
outer tube 9.
[0039] As shown in FIG. 8, the drive shaft 11 is rotatably
supported by the bearings 18 in the outer tube 9. The drive shaft
11 on the proximal end of the outer tube 9 is rotatable relative to
the outer tube 9 and is immovable in the axial direction. For this
configuration, a fixed bearing 28 including the bush holder 19 and
the ball bearing 21 of the bearing 18 is used.
[0040] As shown in FIG. 9, the fixed bearing 28 includes the bush
holder 19, the ball bearing 21, and a bush 25 having a through
hole. The bush holder 19 is fixed to the proximal end of the
interior of the outer tube 9 with a tapping screw 38. The bush 25
having a partially different shape from the drive bush 20 is fixed
to the drive shaft 11. The bush 25 is moved to a predetermined
position of the drive shaft 11 and is fixed to the drive shaft 11
with a hexagon socket screw 39. Since the bush 25 is fixed thus to
the drive shaft 11, as shown in FIG. 12, the three helical convex
portions do not need to be formed on the inner surface of the bush
25.
[0041] The drive shaft 11 with the fixed bush 25 is inserted into
the outer tube 9, the bush 25 is disposed facing the bush holder 19
fixed in the outer tube 9, the ball bearing 21 is disposed between
the bush 25 and the bush holder 19, and then the ball bearing 21 is
fixed using a snap ring 27. The arrangement of the bush 25, the
bush holder 19, and the ball bearing 21 rotatably holds the bush 25
relative to the bush holder 19. With this configuration, the drive
shaft 11 on the proximal end of the outer tube 9 is rotatable
relative to the outer tube 9 and is immovable in the axial
direction. The bush holder 19 for the fixed bearing 28 is used to
reduce the cost through commonality of components. This allows the
use of other special components.
[0042] In the outer tube 9, the four bearings 18 are disposed.
Furthermore, springs 29 are disposed between the bearings 18,
between the bearing 18 on the most proximal end and the fixed
bearing 28, and between the bearing 18 on the most distal end and
the proximal end of the inner tube 10. The springs 29 locate the
bearings 18 at equal intervals in the outer tube 9. The intervals
vary with an extension and retraction of the rod section 4 but are
kept constant. Thus, the bearings 18 are equally spaced so as to
support the drive shaft 11 with a fixed clearance, suppressing
vibrations during the rotation of the drive shaft 11.
[0043] The number of bearings 18 is properly determined according
to the length of the drive shaft 11. In the extendible working
machine 1, the drive shaft 11 has a maximum rotation speed of at
least 10000 rpm. If the drive shaft 11 has a small outside diameter
of 6.5 mm, a larger interval between the bearings 18 may bend the
drive shaft 11 between the bearings 18 and thus cause a rope
skipping phenomenon leading to large vibrations. For this reason,
the intervals between the bearings 18 need to be reduced. If the
number of bearings 18 is excessively increased, however, the cost
may rise and an extension and retraction of the rod section 4 may
disadvantageously decrease with an increased number of the bearings
18 and the springs 29. In consideration of this point, if the drive
shaft 11 has a length of 2043 mm (except for the joint 14), as
mentioned above, the four bearings 18 are used to suppress
vibrations. In this way, it is preferable to properly set the
number of bearings 18 and the intervals between the bearings
18.
[0044] A stopper 30 is provided on the proximal end of the inner
tube 10 such that the pipe shaft 12 disposed in the inner tube 10
is rotatable relative to the inner tube 10 and is immovable in the
axial direction. As shown in FIG. 10, the stopper 30 includes the
bush holder 19, the ball bearing 21, and the connecting pipe
15.
[0045] The bush holder 19 with the inserted proximal end of the
inner tube 10 is fixed by blind rivets 40. The pipe shaft 12 is
disposed in the inner tube 10 such that the connecting pipe 15
fixed on the proximal end of the pipe shaft 12 is opposed to the
bush holder 19 fixed to the inner tube 10. Subsequently, the ball
bearing 21 is press-fitted between the bush holder 19 and the
connecting pipe 15 and is fixed by the snap ring 27.
[0046] The arrangement of the bush holder 19, the connecting pipe
15, and the ball bearing 21 supports the connecting pipe 15
rotatably relative to the bush holder 19. With this configuration,
the pipe shaft 12 on the proximal end of the inner tube 10 is
rotatable relative to the inner tube 10 and is immovable in the
axial direction.
[0047] Moreover, the four bearings 31 are fixed at equal intervals
in the axial direction in the inner tube 10 and the pipe shaft 12
is rotatably supported by the bearings 31 in the inner tube 10. As
shown in FIGS. 2 and 3, the bearing 31 includes a cylindrical bush
holder 32 and a metal bush 33 press-fit to the inner surface of the
bush holder 32. Moreover, the pipe shaft 12 is inserted into the
metal bush 33 and thus is rotatably supported in the inner tube
10.
[0048] The inner tube 10 with the rotatably disposed pipe shaft 12
is placed so as to move in the axial direction in the outer tube 9.
The spring 29 is disposed between the bush holder 19 fixed to the
proximal end of the inner tube 10 and the bearing 18 on the most
distal side in the outer tube 9. Furthermore, a slide holder 34 for
fastening and releasing the inner tube 10 on the outer tube 9 is
disposed on the proximal end of the outer tube 9.
[0049] As shown in FIGS. 2 and 3, the slide holder 34 is designed
for the outside diameter of the outer tube 9. The slide holder 34
is a substantially cylindrical member having a step including a
large-diameter portion surrounding the outer tube 9 and a
small-diameter portion surrounding the inner tube 10. The slide
holder 34 has a slit in the axial direction and is made of a
deformable material, e.g., resin. Moreover, the slide holder 34
includes a bolt 35 for adjusting a slit opening and a knob 36 for
tightening and loosening the bolt 35.
[0050] A portion of the slide holder 34 surrounds the outer tube 9
so as to be fixed to the outer tube 9 while another portion of the
slide holder 34 surrounds the inner tube 10 without being fixed to
the inner tube 10. However, tightening of the bolt 35 with the knob
36 reduces the slit opening so as to reduce the diameter of the
portion of the slide holder 34 around the inner tube 10, tightening
the outer surface of the inner tube 10 with the slide holder 34 so
as to prevent the inner tube 10 from moving. This fixes the inner
tube 10 to the outer tube 9.
[0051] Moreover, loosening of the bolt 35 with the knob 36 extends
the slit opening, allowing the inner tube 10 to move in the axial
direction relative to the outer tube 9. The movement of the inner
tube 10 can extend and retract the rod section 4. In this way, the
inner tube 10 is tightened and loosened by the slide holder 34.
[0052] As shown in FIG. 3, on the outer surface of the inner tube
10, a cushion tube 37 is disposed between the bush holder 19 of the
stopper 30 and a step portion on the inner surface of the slide
holder 34. When the inner tube 10 is moved in a direction that
extends the rod section 4, the elastic force of the cushion tube 37
absorbs an impact caused by a contact between the inner tube 10 and
the slide holder 34.
[0053] An operation of the extension and retraction of the rod
section 4 of the extendible working machine 1 according to the
present invention will be more specifically described below. FIG. 3
is a longitudinal sectional view of the extendible working machine
1 with the most extended rod section 4. As shown in FIG. 3, when
the rod section 4 is most extended, the bearings 18 are evenly
spaced at maximum intervals by the springs 29 with the cushion tube
37 pressed by the bush holder 19 of the stopper 30 into contact
with the step portion on the inner surface of the slide holder 34.
In this state, the inner tube 10 protruding to a maximum length
from the outer tube 9 is fixed by the slide holder 34.
[0054] An operation for retracting the rod section 4 of the
extendible working machine 1 in the state of FIG. 3 will be
described below. The bolt 35 is loosened by the knob 36 of the
slide holder 34. This loosens the inner tube 10 tightened by the
slide holder 34, allowing the inner tube 10 to move relative to the
outer tube 9. In this state, the inner tube 10 is moved into the
outer tube 9.
[0055] At this point, a force is applied to the spring 19 located
between the stopper 30 and the bearing 18 on the most distal side,
all the bearings 18 are moved to the proximal side, and all the
springs 29 are compressed so as to reduce the intervals of the
bearings 18. The pipe shaft 12 at this point is also moved with the
inner tube 10 to the proximal side. The pipe shaft 12 moves in a
rotating manner when the connecting pipe 15 moves in the axial
direction. Thus, the pipe shaft 12 moves to the proximal side while
rotating relative to the drive shaft 11 in the inner tube 10. The
inner tube 10 moves in the axial direction without being rotated by
the ball bearing 21 of the stopper 30 or the metal bush 33 of the
bearing 31.
[0056] FIG. 2 shows that the inner tube 10 is most deeply moved
into the outer tube 9. At this point, the drive shaft 11 is most
deeply inserted into the pipe shaft 12. The inner tube 10 moved
thus compresses the springs 29 such that the bearings 18 are spaced
at minimum intervals. In this state, the springs 29 apply a force
that moves the inner tube 10 to the distal side. Thus, the bolt 35
is tightened by the knob 36 of the slide holder 34 so as to fix the
inner tube 10 on the small-diameter portion of the slide holder 34.
This fixes the inner tube 10 to the outer tube 9.
[0057] When the rod section 4 is retracted, the inner tube 10 is
fixed to the outer tube 9 by the slide holder 34, allowing use of
the rod section 4 fixed with a predetermined length. The rod
section 4 may be fixed with various lengths.
[0058] An extending operation of the rod section 4 will be
described below. On the rod section 4 in the state of FIG. 2, the
bolt 35 is loosened by the knob 36 of the slide holder 34. This can
release the inner tube 9 and move the inner tube 9 in a direction
that protruding from the outer tube 10. At this point, the elastic
force of the spring 29 applies a force to the inner tube 10 in a
direction that protrudes from the outer tube 9, thereby easily
moving the inner tube 10.
[0059] At this point, the springs 29 are extended so as to increase
the intervals of the bearings 18. The pipe shaft 12 moves in the
axial direction according to a movement of the inner tube 10. When
the pipe shaft 12 moves, the connecting pipe 15 moves in the axial
direction in a rotating manner and thus the pipe shaft 12 moves
toward the distal side while rotating relative to the drive shaft
11. The inner tube 10 is moved by the ball bearing 21 of the
stopper 30 and the metal bush 33 of the bearing 31 without
rotations.
[0060] The inner tube 10 is moved to a predetermined position and
then the bolt 35 is tightened by the knob 36 of the slide holder 34
so as to fix the inner tube 10 on the small-diameter portion of the
slide holder 34. In this way, the rod section 4 can be fixed with a
predetermined extended length.
[0061] As has been discussed, the inner tube 10 is fixed and
released by operating the slide holder 34, moving the inner tube 10
in the axial direction. Thus, the rod section 4 can be easily
extended and retracted and fixed. The extendible working machine 1
can be used in the fixed state.
[0062] A method of transmitting the rotational force of the
rotation/drive section 2 in the extendible working machine 1 to the
working section 3 will be described below. The rotational force of
the rotation/drive section 2 is transmitted to the drive shaft 11
via the joint 14 that is connected to the rotation/drive section 2
by spline fitting. The drive shaft 11 having received the
rotational force rotates in the outer tube 9. At this point, the
drive shaft 11 is rotatably supported by the bearings 18 in the
outer tube 9, preventing the rotation of the outer tube 9.
[0063] When the drive shaft 11 rotates, the pipe shaft 12 also
rotates via the connecting pipe 15 where the drive shaft 11 is
inserted. The convex portions 16 provided on the inner surface of
the small-diameter portion of the connecting pipe 15 are located in
the grooves 13 of the drive shaft 11. Thus, the rotation of the
drive shaft 11 brings the grooves 13 into contact with the convex
portions 16 in a circumferential direction, and thus the rotation
of the drive shaft 11 is transmitted to the connecting pipe 15.
Thus, the rotating drive shaft 11 also rotates the pipe shaft 12.
During the rotation of the pipe shaft 12 in the inner tube 10, the
connecting pipe 15 is rotatably supported by the ball bearing 21 of
the stopper 30 and the metal bush 33 of the bearing 31, preventing
a rotation of the inner tube 10.
[0064] When the pipe shaft 12 rotates, a rotational force is
transmitted to the working section 3 that is connected to the joint
17 by spline fitting, through the joint 17 on the end of the pipe
shaft 12. The rotational force transmitted from the rotation/drive
section 2 to the working section 3 drive the working section 3,
actuating the extendible working machine 1 into an operable
state.
[0065] In the extendible working machine 1 according to the present
invention, the use of the drive shaft 11 including the helical
grooves 13 allows the shaft body 8 to have a smaller diameter and a
lighter weight than in the related art. Accordingly, the tube body
7 can be reduced in diameter. Actually, a conventional working
device includes a shaft having a diameter of 12 mm and an outer
tube having a diameter of 47 mm, whereas the extendible working
machine 1 of the present invention includes the drive shaft 11
having a diameter of 6.5 mm and the outer tube 9 having a diameter
of 35 mm. The weight of the conventional working device is 3.7 kg,
whereas the weight of the extendible working machine 1 of the
present invention can be reduced to 2.6 kg. With this
configuration, the rod section 4 can be easily held by a person
with small hands. Because of the light weight and ease of gripping,
the extendible working machine 1 can be more easily handled with a
lighter weight than in the related art.
[0066] The drive shaft 11 is formed by twisting a linear steel rod
on which the three grooves 13 linearly extending in the axial
direction are formed at equal intervals. Thus, even in the use of a
thin and long drive shaft, e.g., the drive shaft 11 having an
outside diameter of 6.5 mm and a length of 2043 mm, the drive shaft
11 can be linearly formed so as to rotate without vibrations,
thereby achieving the extendible working machine 1 that can more
stably transmit a rotational force.
[0067] With this configuration, the extendible working machine 1 of
the present invention can reduce fatigue caused by an extended
period of operations such as trimming of branches at high
elevations and allows a weak person to perform an operation.
[0068] In the present embodiment, the bearings 18, the fixed
bearings 28, and the stopper 30 are partially configured using
common components in the extendible working machine 1, thereby
reducing the manufacturing cost.
REFERENCE SIGNS LIST
[0069] 1 telescopic working device
[0070] 2 rotating unit
[0071] 3 working unit
[0072] 4 pole
[0073] 5 operation unit
[0074] 6 proximal-end tube
[0075] 7 cylindrical body
[0076] 8 shaft body
[0077] 9 outer tube
[0078] 10 inner tube
[0079] 11 drive shaft
[0080] 12 pipe shaft
[0081] 13 groove
[0082] 14 joint
[0083] 15 connecting pipe
[0084] 16 convex portion
[0085] 17 joint
[0086] 18 bearing
[0087] 19 bush holder
[0088] 20 drive bush
[0089] 21 ball bearing
[0090] 22 groove
[0091] 23 convex portion
[0092] 24 convex portion
[0093] 25 bush
[0094] 26 pipe joint
[0095] 27 snap ring
[0096] 28 fixed bearing
[0097] 29 spring
[0098] 30 stopper
[0099] 31 bearing
[0100] 32 bush holder
[0101] 33 metal bush
[0102] 34 slide holder
[0103] 35 bolt
[0104] 36 knob
[0105] 37 cushion tube
[0106] 38 tapping screw
[0107] 39 hexagon socket screw
[0108] 40 blind rivet
* * * * *