U.S. patent number 3,902,322 [Application Number 05/391,984] was granted by the patent office on 1975-09-02 for drain pipes for preventing landslides and method for driving the same.
Invention is credited to Hikoitsu Watanabe.
United States Patent |
3,902,322 |
Watanabe |
September 2, 1975 |
Drain pipes for preventing landslides and method for driving the
same
Abstract
A drain pipe is disclosed which comprises a drain pipe section
provided with a plurality of weep holes or slots and a shielding
pipe section slidably fitted over the drain pipe section and
adapted to remain in such a position with respect to the drain pipe
section as to completely shield the weep holes or slots thereof
when driven into the ground. After the drain pipe section has been
driven into a predetermined depth, the shielding pipe section is
further driven into the ground while the drain pipe section remains
stationary, so that the weep holes or slots are exposed to a
cylinderical cavity left therearound by the shielding pipe
section.
Inventors: |
Watanabe; Hikoitsu (Nakano-ku,
Tokyo, JA) |
Family
ID: |
27519824 |
Appl.
No.: |
05/391,984 |
Filed: |
August 27, 1973 |
Foreign Application Priority Data
|
|
|
|
|
Aug 29, 1972 [JA] |
|
|
47-85883 |
Feb 12, 1973 [JA] |
|
|
48-16526 |
Mar 27, 1973 [JA] |
|
|
48-34091 |
Jul 17, 1973 [JA] |
|
|
48-79949 |
Jul 27, 1973 [JA] |
|
|
48-75530 |
|
Current U.S.
Class: |
405/43; 173/33;
175/19; 175/171 |
Current CPC
Class: |
E21B
15/006 (20130101); E02D 7/06 (20130101); E02D
3/103 (20130101); E21B 7/046 (20130101); E02B
11/00 (20130101); E02D 17/20 (20130101) |
Current International
Class: |
E02B
11/00 (20060101); E02D 7/00 (20060101); E02D
3/10 (20060101); E02D 7/06 (20060101); E02D
3/00 (20060101); E21B 7/04 (20060101); E02D
17/20 (20060101); E02B 011/00 (); E21B
011/02 () |
Field of
Search: |
;61/35,36,11,13,53.7
;175/19,22,171 ;166/227 ;173/33 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Shapiro; Jacob
Attorney, Agent or Firm: Jecies; Saul
Claims
What is claimed is:
1. A drain unit for draining a sloping ground formation and thus
preventing landslides due to excess ground water by installing said
drain unit at a slight upward inclincation relative to the
horizontal, comprising
a drain pipe having a plurality of circumferentially distributed
openings and adapted to be driven into the sloping ground at said
inclination;
a shielding pipe telescoped over and slidably surrounding said
drain pipe and covering said openings thereof; and
connecting means connecting the telescoped-together pipes for joint
driving thereof at said inclination into the sloping ground
formation to a desired depth, and for thereafter driving said
shielding pipe alone beyond said desired depth so as to displace
said shielding pipe forwardly with reference to said drain pipe and
expose said opening while leaving about said drain pipe in the
region of said openings an annular clearance in which the soil is
substantially spaced from said drain pipe.
2. A method of preventing landslides by draining water from sloping
ground, comprising the steps of
driving into the sloping ground at an upward angle relative to the
horizontal an assembly composed of a drain pipe having apertures,
and a shielding pipe telescoped over said drain pipe and covering
said apertures;
discontinuing driving of said assembly when the same has reached a
desired depth; and
thereafter driving said shielding pipe alone deeper into the ground
so as to axially displace said shielding pipe relative to and
forwardly of said drain pipe to thereby expose said apertures in
the drain pipe while simultaneously forming an annular clearance
about the drain pipe in which the soil is substantially spaced from
said drain pipe.
3. A method as defined in claim 2; and further comprising the step
of drilling weep-holes into the sloping ground in substantially
vertical direction, and filling said weep-holes with sand, so as to
improve the permeability of the ground to water and facilitate the
run-off of the water into said drain pipe.
4. A drain unit for draining a sloping ground formation and thus
preventing landslides due to excess ground water by installing said
drain unit at a slight upward inclinations relative to the
horizontal, comprising
a drain pipe having a plurality of circumferentially distributed
slots and adapted to be driven into the sloping ground at said
inclinations;
a shielding pipe telescoped over and slidably surrounding said
drain pipe and covering said slots thereof; and
connecting means connecting the telescoped-together pipes for joint
driving thereof at said inclinations into the sloping ground
formation to a desired depth, and for thereafter driving said
shielding pipe alone beyond said desired depth so as to displace
said shielding pipe forwardly with reference to said drain pipe and
expose said said slots while leaving about said drain pipe in the
region of said slots an annular clearance in which the soil is
substantially spaced from said drain pipe.
5. A drain unit as defined in claim 4; and further comprising
soil-displacing means mounted on a leading end of said drain pipe
when said pipes are jointly being driven into the ground.
6. A drain unit as defined in claim 4; and further comprising a
string of extension pipes for extending the length of said drain
pipe; and coupling means for coupling said extension pipes to one
another and to said drain pipe.
7. A drain unit for draining a sloping ground formation and this
preventing landslides due to excess ground water by installing said
drain unit at a slight upward inclinations relative to the
horizontal, comprising
a drain pipe having a plurality of circumferentially distributed
openings and adapted to be driven into the sloping ground at said
inclinations, said openings being equi-angularly spaced about said
drain pipe and extending from a trailing end towards a leading end
thereof;
a shielding pipe telescoped over and slidably surrounding said
drain pipe and covering said openings thereof; and
connecting means connecting the telescoped-together pipes for joint
driving thereof at said inclination into the sloping ground
formation to a desired depth, and for thereafter driving said
shielding pipe alone beyond said desired depth so as to displace
said shielding pipe forwardly with reference to said drain pipe and
expose said openings while leaving about said drain pipe in the
region of said openings an annular clearance in which the soil is
substantially spaced from said drain pipe, said connecting means
comprising a member mounted on the rear end of said shielding pipe
and having fins slidably received in the respective openings of
said drain pipe.
8. A method of preventing landslides by draining water from sloping
ground, comprising the steps of
providing a drain pipe assembly composed of a drain pipe having
apertures, and a shielding pipe telescoped over said drain pipe and
covering said apertures;
suspending said drain pipe at two axially spaced locations thereof
in a substantially horizontal orientation, so that said drain pipe
can perform axial swinging movements;
executing blows upon a trailing end of said drain pipe for driving
said head and drain pipe substantially horizontally into the
sloping ground;
discontinuing driving of said assembly when the same has reached a
desired depth; and
thereafter driving said shielding pipe alone deeper into the ground
so as to axially displace said shielding pipe relative to and
forwardly of said drain pipe to thereby expose said apertures in
the drain pipe while simultaneously forming an annular clearance
about the drain pipe in which the soil is substantially spaced from
said drain pipe.
9. A method as defined in claim 8, wherein the step of suspending
comprises suspending said drain pipe so that said leading end hangs
at a slight upward inclination relative to the horizontal.
Description
BACKGROUND OF THE INVENTION:
The present invention relates to drain pipes for driving into the
natural slopes, earth dams or enbankments in which landslides tend
to occur in order to drain excessive seeping water so that the
water content may be maintained at a safe level, the drain pipes
being driven into the ground without disturbing the stability of
the slopes or the like.
The true causes of landslides have not been clarified yet, but it
is well known that a sudden landslide is triggered by a heavy rain
because the seeping water becomes in excess of the maximum
allowable permeability of the soil, sand and rocks. Therefore it
must be a very effective countermeasure against landslides to drain
excessive seeping water in the slopes or embankments so that the
water content may be always maintained at a safe level. In this
case it is imperative to drive drain pipes into the slopes or the
like without adversely affecting the stability thereof.
In view of the above there has been proposed a method for driving
drain pipes of the type having one or leading end terminated into a
cone-shaped point and being provided with a plurality of weep holes
or slots. The drain pipe is set horizontally or inclined downwardly
toward the open end, and, if required, is joined to an extension
pipe or pipes so that the drain pipe may be set to a predetermined
depth. However, when the drain pipe is driven into the ground the
soil and sand enters into the drain pipe through the weep slots or
holes so that clogging of the drain pipe tends to very frequently
occur. As a result, even when the drain pipe is set to a
predetermined depth it serves no useful purpose at all. In order to
overcome this problem, there has been proposed a method for
charging water by a pump into the driven drain pipe, thereby mixing
clogging soil or sand with water to discharge it outside of the
drain pipe. This step is repeated many times until the clogged weep
holes or slots are opened and a cavity or cavities are formed
around the weep holes or slots by the erosin of soil or sand
surrounding them, by the charged water. Thus, water collected in
the cavities may be discharged through the weep holes or slots, the
drain pipe and the extension pipe or pipes. However, the quantity
of soil or sand which is discharged by the pumped water is very
limited and the operation is time consuming and requires much
labor. Furthermore the operation is extremely difficult when a
drain pipe is driven very deep into the ground.
SUMMARY OF THE INVENTION:
In view of the above one of the objects of the present invention is
to provide an improved drain pipe for preventing landslides which
may substantially eliminate the defects encountered in the
conventional drain pipes.
According to one embodiment of the present invention a drain pipe
comprises drain pipe section having a drill section attached to the
leading end thereof and provided with a plurality of axial weep
slots and a shielding pipe section slidably fitted over the drain
pipe section and having a sufficient length to completely shield
the weep slots. When the drain pipe is driven into the ground the
shielding pipe section is adapted to remain in such a position as
to completely shield the weep slots of the drain pipe section.
After the drain pipe has been set to a predetermined depth a
driving rod is inserted through the drain pipe section or sections
and extension pipes so that the driving impact may be applied only
to the shielding pipe section. As a result the shielding pipe
section is further driven into the ground while the drain pipe
section remains completely stationary so that the weep slots may be
exposed to a cylindrical cavity left therearound by the shielding
pipe section.
The above and other objects, features and advantages of the present
invention will become more apparent from the following description
of some preferred embodiments thereof taken in conjection with the
accompanying drawing.
BRIEF DESCRIPTION OF THE DRAWING:
FIG. 1 is a side view of first embodiment of a drain pipe in
accordance of the present invention with a shielding pipe section
being remained in a position for shielding weep slots of a drain
pipe section;
FIG. 2 is a side view thereof with the shielding pipe section being
further driven so as to expose the weep slots;
FIG. 3 is a side view of the drain pipe section;
FIG. 4 is a side view of the shielding pipe section;
FIG. 5 is a top view thereof;
FIG. 6 is a side view illustrating the drain pipe driven into the
ground the joined to an extension pipe;
FIG. 7 is a side view of a driving rod assembly used for driving
further the shield pipe section;
FIG. 8 shows the drain pipe set into the ground;
FIG. 9 is a perspective view of a driving apparatus;
FIG. 10 is a diagrammatic view illustrating the interior of a
motor-driven hammer thereof;
FIG. 11 is a side view thereof;
FIGS. 12 and 13 are side views of the driving apparatus shown in
FIG. 9 illustrating the steps of driving the drain pipe;
FIGS. 14 and 15 are perspective view illustrating another driving
appratus and the steps of driving the drain pipe;
FIG. 16 shows the drain pipes of the present invention driven into
a slope;
FIG. 17 is a cross sectional view thereof;
FIG. 18 is a sectional view of a second embodiment of a drain pipe
in accordance with the present invention;
FIG. 20 is a side view of a shielding pipe section thereof;
FIG. 21 is a top view thereof;
FIG. 22 is a side view of an impact transmission member;
FIG. 23 is a top view thereof;
FIG. 24 is a sectional view of a third embodiment of a drain pipe
in accordance with the present invention;
FIG. 25 is a sectional view of a drain pipe section thereof;
FIG. 26 is a sectional view of a shielding pipe section thereof;
and
FIGS. 27-29 are side views illustrating the steps of driving the
drain pipe shown in FIG. 24.
DESCRIPTION OF THE PREFERRED EMBODIMENTS:
First Embodiment, FIGS. 1-4
First referring to FIG. 1, a drain pipe 30 in accordance with the
present invention is shown as generally comprising a drain pipe
section 31 and a shielding pipe section 32.
As best shown in FIG. 3, the drain pipe section 31 consists of a
steel pipe having a desired length and diameter and is provided
with four equiangularly spaced axial weep slots 33 extending from
the rear end of the drain pipe section 31 over a predetermined
length. A coupling or socket 34 is screwed over the rear end of the
drain pipe section 31 in order to join the drain pipe section 31 to
an extension pipe to be described in more detail hereinafter. The
leading end of the drain pipe section 31 terminates in a drill
section 36 having four cutting edges 35 equiangularly spaced from
each other.
As best shown in FIGS. 4 and 5 the shielding pipe section 32 has an
inner diameter so that it may be slidably fitted over the drain
pipe section, 31 and such a length as to shield the weep slots 33
of the drain pipe section 31 when fitted thereover. The rear end of
the shielding pipe section 32 terminates into a cross-shaped impact
receiving member 37 with four ridges which are adapted to be
loosely fitted into the weep slots 33 of the drain pipe section 31
when the shielding pipe section 32 is fitted over the drain pipe
section 31.
In assembly the shielding pipe section 32 is fitted over the drain
pipe section 31 with the edges of the impact receiving member 37
fitted into the weep slots 33 of the drain pipe section 31, and
thereafter the coupling or socket 34 is screwed to the rear end of
the drain pipe section 31. Then, the shielding pipe section 32 is
slidable over the drain pipe section 31, and when the impact
receiving member 37 is in abuttment with the coupling or socket 34
it may completely shield the weep slots 33 of the drain pipe
section 31 as best shown in FIG. 1. On the other hand when the
shielding pipe section 32 abuts against the rear end of the drill
section 36 the weep slots 33 are completely exposed as best shown
in FIG. 2.
Driving Apparatus, FIGS. 9-15
Next referring to FIGS. 9-15, the driving apparatus generally
indicated by 50 and 51 for driving the drain pipe of the type
described hereinbefore into the ground will be described
hereinafter. The driving apparatus 51 shown in FIGS. 9-13 is used
for driving the drain pipes of the present invention into the
ground relatively close to the base of the slope whereas the
driving apparatus 51 shown in FIGS. 14 and 15 is used for driving
the drain pipes into the slope except the place where the driving
apparatus 50 is applicable.
Referring to FIG. 9 the driving apparatus generally indicated by 50
comprises three supports 54a, 54b, and 54c each of which consists
of a top brace member 52 and a pair of legs 53 joined to pedestals
56, respectively, through turnbuckles so that the height of each
leg 53 may be adjustable. An anchor pile 57 is driven into the
ground through a hole formed through the pedestal 56 so that the
pedestal 56 may be securely held in position. A socket 58 is
securely fixed to the top brace member 52 at the center thereof for
receiving therein the end of a guide rod 59 of a desired length.
The guide rods 59 are securely held in the sockets 58 by means of
bolts 60. Therefore the supports 54a, 54b and 54c may be spaced
apart by a predetermined distance from each other and held securely
upon the ground.
The driving apparatus 50 further comprises a movable frame
generally indicated by 61 and adapted to move along the guide rods
59. The movable frame 61 comprises a horizontal beam carried by
carriages 67, a vertical rod 62 extending downwardly from the end
of the horizontal beam remote from the right carriage 67 and having
its lower end terminated into a guide plate 64 with a drain pipe
guide hole 63, and a pair of quadrant guide members 65 having their
ends joined to the horizontal and vertical beams, respectively. The
pair of guide members 65 also serve as brace members between the
horizontal and vertical beams 61 and 62, and guide a pendulum rod
69 of a motor-driven hammer 66 to be described in more detail
hereinafter. The carriages 67 are similar in construction, and each
comprises a pair of frames 67 having a roller 68 attached thereto.
The rollers 68 ride on the guide rods 59 so that the movable frame
61 may be movable in parallel with the guide rods 59 as the drain
pipe 30 is driven into the ground in a manner to be described in
more detail hereinafter.
In order to drive the drain pipe 30 into the ground, the
pendulum-like motor-driven hammer 66 suspended by the pendulum rod
69 which in turn is pivoted to the right carriage 67 with a pivot
70 and is guided by the guide members 65 so as to prevent lateral
movement is provided.
Next referring to FIGS. 10 and 11 the motor-driven hammer 66 will
be described. Within a housing 71 a pair of motors 73 are mounted
upon a mount 72, and a winch comprising a drum 77 with a wire rope
78 wound therearound and a clutch 76 is loosely supported by a
shaft 75 which in turn in supported by a pair of brackets 74
securely fixed to the mount 72. The rotation of each motor 73 is
transmitted to the shaft 75 through a belt drive consisting of a
drive pulley 80 fixed to a driving shaft of the motor 73, a driven
pulley 81 fixed to the shaft 75 and an endless belt 82 wrapped
around the driving and driven pulleys 80 and 81.
The right clutch section 76 which is loaded with a spring 91 is
provided with an annular groove 83 into which is fitted a pin 85
extending from one end of an actuating or operating lover 84 which
is pivoted to the base 72 with a pin 86 and whose the other end is
pivoted to a plunger with pin 88 of a plunger and solenoid assembly
87. Therefore, as the plunger and solenoid assembly 87 is energized
or de-energized the right clutch section 76 is slidably moved along
the shaft 75 to engage with or disengage from the mating left
clutch section 89.
One end of the wire rope 78 is securely fixed to the drum 77
whereas the other end is fixed to an ear 90 fixed to the horizontal
beam 61 (See FIG. 9).
A brace rod 92 which is joined to the brackets 74 serves to ensure
that the wire rope 78 will be wound around the drum 77.
When the motors 73, which are supplied with power through a cable
93, are driven, their rotation is transmitted to the clutch section
76 through the driving pulley 80, the endless belt 82, the driven
pulley 81 and the shaft 75. When the clutch section 76 is engaged
with the mating clutch section 89 as the plunger and solenoid
assembly 87 is energized, the drum 72 which is loosely fitted over
the shaft 75 is rotated to wind the wire rope 78 theraround. As a
consequence the motor-driven hammer 66 is swung about the pin 70
upwardly. When the solenoid 87 is de-energized when the
motor-driven hammer 66 is lifted to a predetermined height, the
right clutch section 86 is disengaged from the left clutch section
89 so that the free rotation of the drum 77 is permitted. As a
result the motor-driven hammer 66 swings back to drive the drain
pipe 30 as shown in FIG. 12. The pendulum-like driving operation is
cycled so that the drain pipe 30 is gradually driven into the
ground as shown in FIG. 13.
The driving apparatus 51 which will be described hereinafter with
reference to FIGS. 14 and 15 is substantially similar in
construction to the driving apparatus 50, except its supports or
supporting frames are different. As shown in FIG. 14 the left end
of the guide rod 94 is joined to a pipe 96 with a bolt 97 of a foot
member 95 securely held in position on the slope by means of anchor
piles 109. The right end of the guide rod 94 is supported by a
supporting frame generally indicated by 103. The supporting frame
103 comprises an inverted U-shaped upper leg 99 whose lower end
portions are telescopically fitted into lower legs 101 whose lower
ends are securely fixed to pedestals 100 which in turn are securely
held in position by means of the anchor piles 109. The height of
the supporting frame 103 is therefore adjustable and the inverted
U-shaped leg 99 can be securely held in position relative to the
lower legs 101 by means of bolts 102.
The supporting frame 103 is further supported by a pair of
telescopic brace means, each comprising an inner brace rod 105
whose one end is pivoted to the inverted U-shaped leg 99 with a pin
or rivet 104 and whose the other end portion is telescopically
fitted into and securely held in position with respect to an outer
brace pipe 107 with a bolt 108. The outer brace pipe 107 is
securely fixed to a foot which in turn is securely held in position
on the slope by means of the anchor piles 109. The length of the
telescopic brace means is therefore adjustable. Furthermore stay
wire ropes or chains 110 are extended from anchor bolts (not shown)
driven into the ground on the slope and are fixed to hooks 111
fixed to the pedestals 100 so that the pedestals 100 may be further
securely held in position.
The movable frame 61 and the pendulum-like motor-driven hammer 66
are mounted in a manner substantially similar to that of the
driving apparatus 50, but it should be noted that the motor-driven
hammer 66 is not suspended from the carriage 67 but from a
suspending frame 112 fixed to the horizontal beam 61, that instead
of the guide plate 64 a U-shaped guide member 64 made of a rod is
used and that the guide members 65 are straight. The above
arrangements different from those of the driving apparatus 50 are
merely a matter of design, and both the driving apparatus 50 and 51
are based upon the same principle.
The driving apparatus 50 or 51 is used to drive the drain pipes 30
into the slope, depending upon the positions on the slope where the
drain pipes 30 are driven. In operation the movable frame 61 is
moved to the initial or right position as shown in FIGS. 12 and 14,
and the drain pipe 30 to be driven is inserted through the guide
plate or member 64 so that the drill section of the drain pipe 30
may be placed in correct position. Thereafter, an impact receiving
cap 114 is screwed to the rear end of the drain pipe section 31, so
that the starting position of the guide member or plate 64 and
hence of the movable frame 61 is automatically determined.
Thereafter, the motor-driven hammer 66 is operated in the manner
described hereinbefore to give the driving impact to the impact
receiving cap 114, thereby driving the drain pipe 30 into the
ground. As the drain pipe 30 is driven into the ground the movable
frame 61 and hence the motor-driven pendulum hammer 66 are
automatically advanced because of the engagement of the impact
receiving cap 114 with the guide plate or member 64 as shown in
FIGS. 13 and 15.
As the drain pipe 30 is driven into the ground the shielding pipe
section 32 slidably fitted over the drain pipe section 31 makes
contact with the surface of the ground before the closed ends of
the weep slots 33 of the drain pipe section 31 are driven into the
ground so that the shielding pipe section 32 remains undriven into
the ground while the drain pipe section 31 is driven into the
ground. When the rear end of the shielding pipe section 32 contacts
with the coupling or socket 34, the driving impact is also
transmitted to the shielding pipe section 32 so that it is driven
into the ground together with the drain pipe section 31 as shown in
FIG. 1. Before the coupling or socket 34 is driven into the ground,
the driving operation is suspended to remove the cap 14, thereby
releasing the guide member or plate 64 from the drain pipe 30.
Thereafter an extension pipe 115 is joined to the drain pipe 30,
passed through the guide member or plate 64, and has its outer end
screwed to the impact receiving cap 66. Then the extension pipe 115
is driven into the ground with the drain pipe 30 in the manner
described hereinbefore. Any desired number of extension pipes 115
may be joined and driven into the ground as shown in FIG. 6 so that
the drain pipe 30 may be driven to a predetermined depth. When the
drain pipe 30 is driven the shielding pipe section 32 remains in
engagement with the coupling 34 because of the resistance
encountered from the soil so that the weep slots 33 may be
completely covered by the shielding pipe section 32 and soil or
sand is prevented from entering into the drain pipe 30 through the
weep slots 33 thereof.
After the drain pipe 30 together with the extension pipes 115 are
set to a desired depth, a plurality of solid steel rods 116 with a
suitable length are joined to a suitable length. That is, each
solid steel rod 116 has an internally threaded hole and an
externally threaded projection so that the externally threaded
projection may be screwed into the internally threaded hole as
shown at 117 in FIG. 7. The outer diameter of the steel rods 116 is
so selected that the steel rod assembly may be slidably fitted into
the extension pipes 115, and the length of the steel rod assembly
is so selected that is extends out of the last extension pipe 115
by a predetermined length for the reason to be described
hereinafter when the leading end of the jointed steel rods 115 is
in engagement with the cross-shaped impact receiving member 37 of
the shielding pipe section 32. The driving impact is applied to the
steel rod assembly 115 in the manner described hereinbefore so that
only the shielding pipe section 32 is driven further into the
ground until it abuts against the drill section 36 while the drain
pipe section 31 remains stationary as shown in FIG. 8. As a
consequence the weeping slots 33 of the drain pipe section 31 are
exposed and a cylindrical cavity 118 is formed around them as shown
in FIG. 8. When the steel rod assembly 115 is withdrawn, the drain
pipe driving operation is completed.
FIGS. 16 and 17 illustrate the drain pipes and extension pipes
driven into the slope 113 where there is a danger of landslide.
Since the weep slots 33 are all exposed and the cylindrical
cavities 118 are formed around them, the excessive seeping water is
discharged through the drain pipe sections 31 and the extension
pipes 115 so that the water content may be maintained at a level at
which no landsliding will occur. The drain pipes 30 and the
extension pipes 115 are driven into the slope without adversely
affecting the inherent stability thereof. In some cases, because of
the poor permeability of the soil the excessive seeping water
cannot be drained satisfactorily even when many drain pipes are
driven. To overcome this problem weep holes 119 may be drilled from
the crown of the slope by any conventional method and filled with
sand to form vertical sand drains.
Second Embodiment of Drain Pipe, FIGS. 18-23
Next referring to FIGS. 18-23, the second embodiment of the drain
pipe of the present invention will be described hereinafter.
Briefly stated, the second embodiment 30a is similar in
construction to the first embodiment except (a) that the drain pipe
section 31a is provided with only a pair of opposed axial weep
slots 33a, (b) that the cross-shaped impact receiving member 37a of
the shielding pipe section 32a has therefore a pair of opposed
ridges adapted to be loosely fitted into the weep slots and a pair
of opposed short ridges which are spaced apart from the inner wall
of the shielding pipe section 32a so that the drain pipe section
31a may be loosely fitted between the inner wall of the shielding
pipe section 32a and the leading edges of the short ridges, and (c)
that the coupling or socket 34a may be detachably attached to both
ends of the drain pipe section 31a whereas the drill section 36a
may be also attached to the leading end of the drain pipe section
31a.
In driving operation, after the shielding pipe section 32a is
fitted over the drain pipe section 31a, the drill section 36a and
the coupling or socket 34a are screwed to the ends of the drain
pipe section 31a respectively. The drain pipe 30a may be driven
into the ground in a manner substantially similar to that of the
first embodiment by the driving apparatus 50 or 51, but according
to the second embodiment instead of extension pipe 115 another
drain pipe 30a may be joined to the first drain pipe 30a through
the coupling or socket 34a. In this case an impact transmission
member 39 is inserted into the second drain pipe section 33a as
best shown in FIG. 18. As shown in FIGS. 22 and 23 the impact
transmission member 39 has a length substantially equal to the
distance between the cross-shaped impact receiving members 37a of
the first and second drain pipe sections 33a and is provided with
at least three fin-like positioning members 38 so that the impact
transmission member 39 may be positioned substantially coaxially of
the drain pipe section 31a. In like manner a desired number of
drain pipes 30a may be joined and driven into a predetermined depth
as shown in FIG. 18. Thereafter a steel rod 116a which is longer
than the shielding pipe section 32a or the weep slots 33a is
inserted into the last drain pipe section 31a to drive the
cross-shaped impact receiving member 37a thereby driving further
the shielding pipe section 32a into the ground over the drain pipe
section 31a so as to expose the weep slots 33a. The driving impact
is successively transmitted to the cross-shaped impact receiving
members 37a of the successive shielding pipe sections 32a through
the impact transmission members 39 so that all of the shielding
pipe sections 32a may be further driven into the ground while the
drain pipe sections 31a remain stationary. Therefore all of the
weep slots 33a are exposed and the cylindrical cavities 118 are
formed therearound as with the case of the first embodiment.
Third Embodiment of Drain Pipe, FIGS. 24-29
In the first and second emboidments described hereinbefore the
drill section 36 or 36a is attached to the leading end of the drain
pipe section 33 or 33a, but in the third embodiment a drill section
46 is attached to the leading end of the shielding pipe section 41
as shown in FIGS. 24 and 25. The length of the shielding pipe
section 42 is so selected that when it is fitted over the drain
pipe section 41 its trailing or rear end abuts against the socket
or coupling 49 screwed to the rear end of the drain pipe section 41
whereas the leading end of the drain pipe section 41 makes a slight
contact with the inner surface of the drill section 46. The drain
pipe section 41 is provided with a plurality of weep holes 43 as
best shown in FIG. 25.
In driving operation the driving impact is transmitted from the
socket or coupling 47 of the drain pipe section 41, joined or not
joined to the extension pipe 115, to the drill section 46 of the
shielding pipe section 42 so that the drain pipe generally
indicated by 40 is driven into the ground as shown in FIG. 27.
After the drain pipe 40 and the extension pipe or pipes 115 have
been driven to a predetermined depth, an operating steel rod 116
having a suitable length is inserted into the extension pipes 115
and the drain pipe section 41, and thereafter the driving impact is
exerted to the operating steel rod 116 so that the operating steel
rod 116 pushes the drill section 46 so as to drive only the
shielding pipe section 42 into the ground while the drain pipe
section 41 remains stationary as shown in FIG. 28. As a result the
weep holes 43 of the drain pipe section 41 are all exposed and the
cylindrical cavity is formed around them as with the case of the
first and second embodiment as shown in FIG. 29.
So far the preferred embodiments of the present invention have been
described in detail with reference to the accompanying drawing, but
it is to be understood that variations and modifications may be
effected without departing the true spirit of the present
invention.
* * * * *