Liquid jetting apparatus including position change and detector mechanisms

A liquid jetting apparatus includes a drive mechanism, fixed, rotating and jetting cylinder sections connected in order, first rotation transmission mechanism connected to the drive mechanism and having a first operating element, second rotation transmission mechanism connected to the drive mechanism and having a second operating element, the rotational speed of the second rotation transmission mechanism being slightly different from that of the first rotation transmission mechanism, a first operating rod connected at its one end to the first rotation transmission mechanism through a position change mechanism and at its other end to the jetting cylinder section, a second operating rod connected at its one end to the second rotation transmission mechanism and at its other end to the rotating cylinder section, and a detector for detecting the positions of the first operating element and the second operating element and reversing the direction of rotation of the drive mechanism when both operating elements are present at a prescribed position.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to a liquid jetting apparatus, more particularly to 
a liquid jetting apparatus used, for example, to fluidize sludge 
accumulated in an oil tank by jetting it with a washing liquid or the 
like. 
2. Description of the Prior Art 
Numerous liquid jetting apparatuses for use in cleaning the interiors of 
oil tanks have been proposed, including those described in Japanese 
Utility Model Appln. Publications Hei 4-33275, Sho 58-9674, Sho 59-36281 
and Sho 58-23435, Japanese Utility Model Appln. Public Disclosure Hei 
4-110158, Japanese Patent. Appln. Public Disclosure Sho 56-15855 and U.S. 
Pat. No. 4,426,233. All of these apparatuses are supplied high-pressure 
washing liquid whose high pressure is used to rotate a turbine and, in 
turn, to rotate or swing the nozzle section that jets the washing liquid. 
In a method which rotates a turbine using the high pressure of supplied 
washing liquid, however, the jetting pressure of the washing liquid is 
naturally lowered by the resistance of the turbine. Under some 
circumstances, this reduction of the washing liquid jetting pressure 
prolongs the period required for breaking down solidified sludge in an oil 
tank or makes it impossible to achieve adequate breakdown. 
In addition, a particular problem is encountered when oil is used as the 
washing liquid. Since there is no way of preventing the oil from getting 
into the turbine and other mechanical parts, the oil is liable to be 
ignited by frictional heat or sparks produced by the operation of the 
mechanical sections. 
This invention was accomplished in the light of the foregoing circumstances 
and has as one of its objects to provide a liquid jetting apparatus which 
does not reduce the jetting pressure of the washing liquid. 
Another object of the invention is to provide a liquid jetting apparatus 
that ensures safe, fire-free operation since it does not include a turbine 
which could produce frictional heat or sparks. 
Another object of the invention is to provide a liquid jetting apparatus 
that with a simple configuration enables washing liquid to be jetted in 
the desired direction and over the desired range. 
SUMMARY OF THE INVENTION 
For achieving these objects, the invention provides a liquid jetting 
apparatus comprising drive means including a motor, a fixed cylinder 
section disposed under the drive means, a rotating cylinder section 
rotatably disposed at the lower end of the fixed cylinder section and 
having a free end with an inclined end surface, a jetting cylinder section 
having an inclined upper end face-to-face with the inclined end surface of 
the rotating cylinder section and a lower end equipped with a liquid 
jetting nozzle, the jetting cylinder section being rotatably connected to 
the rotating cylinder section, first rotation transmission means connected 
to the drive means and having a first operating element, second rotation 
transmission means connected to the drive means and having a second 
operating element, the rotational speed of the second rotation 
transmission means being slightly different from that of the first 
rotation transmission means, a first operating rod connected at its one 
end to the first rotation transmission means through a position change 
means and at its other end to the jetting cylinder section, a second 
operating rod connected at its one end to the second rotation transmission 
means and at its other end to the rotating cylinder section, and detection 
means for detecting the positions of the first operating element and the 
second operating element and reversing the direction of rotation of the 
drive means when both operating elements are present at a prescribed 
position. 
Thus, instead of using the pressure of the supplied washing liquid for 
rotating and swinging the nozzle section the invention provides a separate 
drive system for this purpose. There is therefore no reduction of the 
washing liquid jetting pressure. Moreover, the apparatus is extremely safe 
with regard to the occurrence of fire since it has no turbine to produce 
frictional heat or sparks. Further, owing to the provision of the third 
rotation transmission means, the two means can be operated to control both 
the direction and the swing angle of the jetting cylinder section, whereby 
the jetting of the washing liquid in the desired direction and over the 
desired range can be conducted with ease. 
The above and other features of the present invention will become apparent 
from the following description made with reference to the drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
The drawings show an embodiment of the liquid jetting apparatus according 
to this invention applied to an oil tank washing apparatus. 
Briefly described, the liquid jetting apparatus according to the present 
invention comprises a drive mechanism 1, a fixed cylinder section 2 
provided below the drive mechanism 1, a rotating cylinder section 3 
connected to the lower end of the fixed cylinder section 2 and a jetting 
cylinder section 4 connected to the lower end of the rotating cylinder 
section 3. 
In addition to having the fixed cylinder section 2 provided beneath it, the 
drive mechanism 1 includes a drive means 6, for example, a motor, that is 
connected with a power source (not shown). A drive shaft 7 of the drive 
means 6 is housed in a generally disk-shaped housing 8 which also houses a 
rotating shaft 11 fitted with a rotating gear 10 that meshes with a drive 
gear 9 fitted on the drive shaft 7. The shaft 11 is also fitted above with 
a first transmission gear 12 and below with a second transmission gear 13. 
The first transmission gear 12 and the second transmission gear 13 have a 
slightly different number of teeth. A first rotation transmission 
mechanism 14 is connected to the first transmission gear 12 and a second 
rotation transmission mechanism 15 is connected to the second transmission 
gear 13. 
The first rotation transmission mechanism 14 consists of a first gear 16 
meshed with the first transmission gear 12, a first short cylinder member 
17 standing on and integral with the upper surface of the first gear 16, 
and a disk-shaped position change plate 19 fixed on the top of the first 
short cylinder member 17 and having a plurality of apertures 18 formed 
along its outer edge. On the position change plate 19 is provided a third 
rotation transmission mechanism (direction change mechanism) 29 consisting 
of an arm-like connecting plate 21 having a long first operating rod 22 
fixed at one end and an extractable pin 20 at the other end. Inserting the 
pin 20 into an aperture 18 of the position change plate 19 links the 
position change plate 19 with the connecting plate 21 so that the rotation 
of the first transmission gear 12 is reduced and transmitted to the first 
operating rod 22 through the first rotation transmission mechanism 14 and 
the third rotation transmission mechanism 29. 
In the embodiment of FIG. 7, the position change plate 19 is provided about 
its periphery with four apertures 18A, 18B, 18C, 18D. Extracting the pin 
20 from the aperture in which it is inserted allows the first operating 
rod 22 to rotate freely with the connecting plate 21. By rotating the 
connecting plate 21 (and the first operating rod 22) in the appropriate 
direction with the pin 20 extracted and then inserting the pin 20 in an 
appropriate aperture of the position change plate 19 it is possible to set 
the start position of the swinging action of the jetting cylinder section 
4, as will be explained below. 
As shown in FIG. 5, the lower end of the first operating rod 22 is 
connected through a flexible joint 23 to a short rod member 25 fitted with 
a second gear 24. The short rod member 25 is rotatably mounted in the 
lower end of the rotating cylinder section 3. The rotating cylinder 
section 3 terminates in an inclined end surface 26 in face-to-face contact 
with an inclined end 27 of the jetting cylinder section 4 and a third gear 
28 fixed to the inclined end 27 engages with the second gear 24. 
Therefore, when the pin 20 is inserted in an aperture 18 of the position 
change plate 19, the rotation of the first transmission gear 12 rotates 
the first operating rod 22, whereby the jetting cylinder section 4 is 
swung about its inclined end 27. In addition, the position from which the 
jetting cylinder section 4 begins swinging can be adjusted by selecting 
the aperture of the position change plate 19 into which the pin 20 is 
inserted. 
The second rotation transmission mechanism 15 consists of a fourth gear 30 
engaged with the second transmission gear 13 and a second short cylinder 
31 depending from the lower surface of the fourth gear 30. A long, 
pipe-like second operating rod 33 is fixed to the lower end of the second 
short cylinder 31 through a short, cylindrical connecting member 32. As 
shown in FIG. 5, the lower portion of the second operating rod 33 is 
connected to the rotating cylinder section 3 through a fixing member 34 
and the jetting cylinder section 4 is connected to the open end of the 
rotating cylinder section 3 so as to be capable of swinging (sweeping) 
motion. Therefore, the rotation of the second transmission gear 13 rotates 
the second operating rod 33, whereby the rotating cylinder section 3 and 
the jetting cylinder section 4 can be rotated about the second operating 
rod 33. Smooth rotation of the second short cylinder 31 is ensured by 
mounting it with respect to the fixed cylinder section 2 via a bearing 35. 
For ensuring that no interference arises between the rotation of the first 
operating rod 22 and the rotation of the second short cylinder 31 and the 
second operating rod 33, the first operating rod 22 is positioned within 
the hollow interiors of the second short cylinder 31 to be freely 
rotatable with respect thereto. 
As shown in FIG. 6, a first operating element 37 is provided on the 
undersurface of the first gear 16 of the first rotation transmission 
mechanism 14 and a second operating element 39 is positioned under the 
first operating element 37 by a support piece 40 projecting laterally from 
an intermediate portion of a third short cylinder 38 provided to stand on 
the upper surface of the fourth gear 30 of the second rotation 
transmission mechanism 15. In addition, a detection member 41 is 
positioned under the second operating element 39 by a support arm 36 
extending from the inner wall of the housing 8. The first operating 
element 37, the second operating element 39 and the detection member 41 
constitute a rotation sync detector. 
Since, as mentioned earlier, the first transmission gear 12 and the second 
transmission gear 13 differ slightly in the number of their teeth, the 
rotational speeds of the first gear 16 and the support piece 40 differ 
slightly so that the first operating element 37 and the second operating 
element 39 are present at the detection member 41 only once every 
prescribed period. When they are both positioned at the detection member 
41, a communication circuit (not shown) sends a signal to the drive means 
6 for rotating it in the opposite direction. As a result, the direction of 
rotation of the rotating cylinder section 3 and the jetting cylinder 
section 4 reverses periodically, as does the swing direction of the 
jetting cylinder section 4. 
As shown in FIG. 6, a disk-shaped frame 47 is fixed to top of the third 
short cylinder 38 and, as shown in broken lines in FIG. 3, a sun gear 49 
rotatable with the first operating rod 22 and a pair of planetary gears 48 
engaged on one side with the sun gear 49 and on the other side with gear 
teeth provided on the inner periphery of the frame 47 are provided inside 
the frame 47. The frame 47 thus supports the upper end of the first 
operating rod 22. 
As best shown in FIG. 2, the fixed cylinder section 2 is equipped with a 
flange section 42 for connection with a washing liquid supply unit (not 
shown) and is fitted at its upper end with a seal 43 for preventing 
washing liquid from getting into the housing 8. The inner surface of the 
seal 43 is equipped with the aforementioned bearing 35 for supporting and 
ensuring smooth rotation of the second short cylinder 31 of the second 
rotation transmission mechanism 15. As shown in FIG. 5, a connecting 
member 45 with an internally fitted bearing 44 is fixed on the lower end 
of the fixed cylinder section 2. The rotating cylinder section 3 is 
rotatably supported by the connecting member 45. As shown in FIG. 1, the 
jetting cylinder section 4 swingably connected to the rotating cylinder 
section 3 is equipped with a liquid jetting nozzle 46 from which the 
supplied washing liquid is jetted at high pressure. The jetting cylinder 
section 4 is a curved pipe configured to point straight down at the bottom 
of its swinging rotation. 
When washing liquid is fed to the liquid jetting apparatus constituted in 
the foregoing manner through the flange section 42 and the drive means 6 
is turned ON, washing liquid is jetted from the liquid jetting nozzle 46 
as the jetting cylinder section 4 slowly swings owing to the rotation of 
the rotating shaft 11 transmitted through the first rotation transmission 
mechanism 14 and also rotates owing to the action of the second rotation 
transmission mechanism 15. 
Since, differently from in the prior art jetting apparatuses, the swinging 
of the jetting cylinder section 4 and the rotation of the rotating 
cylinder section 3 and the jetting cylinder section 4 are not powered by 
the delivery pressure of the supplied washing liquid, there is no risk of 
fire etc. and the jetting pressure of the liquid is not reduced. 
The swing direction and swing angle range of the jetting cylinder section 4 
is controlled by means of the position change plate 19. The detector 
detects when the first operating element 37 and the second operating 
element 39 are aligned in contact with the detection member 41 and at the 
time of the detection invokes control to reverse the driving direction of 
the drive means 6. This enables regulation of the width over which the 
jetting cylinder section 4 is swung as, for instance, shown in FIG. 8. 
More specifically, FIG. 8(a) relates to the case where the pin 20 is 
inserted in the aperture 18B of the position change plate 19 and the 
numbers of teeth of the first transmission gear 12, the second 
transmission gear 13, the first gear 16 and the fourth gear 30 are 
selected such that the first operating element 37 and the second operating 
element 39 align in contact with the detection member 41 when the position 
change plate 19 has made a quarter rotation. Under these conditions, the 
jetting cylinder section 4 swings over a range starting from straight down 
and extending 70 degrees upward, thus making it possible to jet 
high-pressure liquid over substantially the whole bottom surface of the 
tank. FIG. 8(b) relates to the case where the number of teeth of the 
respective gears is left unchanged but the apparatus is operated with the 
pin 20 inserted in the aperture 18A of the position change plate 19. Under 
these conditions, the jetting cylinder section 4 swings over a range 
starting 70 degrees upward of straight down and extending upward by 
another 70 degrees, thus making it possible to jet high-pressure liquid 
onto the side walls and ceiling of the tank. Thus the high-pressure liquid 
jetting direction can be changed by selecting the position at which the 
pin 20 is inserted in the position change plate 19 and, for example, can 
be appropriately adjusted in response to the location etc. of the sludge 
deposited in the oil tank. Moreover, by appropriately determining the 
number of teeth of the gears 12, 13, 16 and 30, it is possible to set the 
swing angle of the jetting cylinder section 4 as desired. 
Although the invention has been explained with reference to an embodiment 
applied to an oil tank washing apparatus, it is in no way limited to the 
described embodiment but changes and modifications may be made within the 
scope of the appended claims. 
As explained in the foregoing, the liquid jetting apparatus according to 
this invention is adapted such that while the first rotation transmission 
mechanism swings the jetting cylinder section the second rotation 
transmission mechanism rotates both the jetting cylinder section and the 
rotating cylinder section 3. Since this makes it possible to jet liquid in 
almost all directions, it is possible to break down, fluidize and 
discharge sludge in the oil tank by means of the jetted liquid. 
Moreover, since a single drive means is used for swinging the jetting 
cylinder section and rotating the rotating cylinder section and the 
jetting cylinder section, energy consumption can be reduced. In addition, 
unlike in the prior art liquid jetting apparatus, the means for driving 
the apparatus is not the delivery pressure of the supplied washing liquid 
and, therefore, there is no risk of fire etc. and the liquid jetting 
pressure is high. Because of this, the breakdown effect and fluidization 
effect with respect to sludge in an oil tank, for example, is very high. 
Since the detector switches over the drive means with the first and second 
operating elements and the detector in an integrally controlled state, it 
is possible to set the swing angle of the jetting cylinder section so as 
to focus the jetted liquid within a prescribed range. 
Furthermore, the provision of the position change mechanism in the third 
rotation transmission mechanism 29 makes it possible to appropriately set 
the start position of the swinging action of the jetting cylinder section 
4, which in combination with the aforesaid detector, makes it possible to 
specify the range of liquid jetting to within a desired region. When the 
apparatus is used for cleaning an oil tank, therefore, the washing liquid 
jetting efficiency can be maximized in response to the location, 
condition, etc. of the sludge in the oil tank, thus making it possible to 
achieve optimum sludge fluidization and discharge.