JPS6141833Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an earth auger expansion device that can freely expand and contract the movable cutting blade at the bottom of the screw shaft from the ground in a drilling machine having an auger shaft.

Recently, in an earth auger that uses a cutting blade attached to the tip of a screw shaft to drill into the ground, the diameter of the root of the hole has been enlarged to increase the supporting load of the pile driven into the hole. A method of injecting cement milk or other hardening fluid into the soil began to be used. However, in the past, in order to enlarge the base of the drilled hole, a movable cutting blade was attached to the lower end of the screw shaft, and when the screw shaft was pushed down strongly, the movable cutting blade was pushed out against the force of the return spring. There were some that pushed the movable cutting blade apart when the screw shaft was reversed.

Hereinafter, an enlargement of a conventional earth auger will be explained with reference to the drawings. Since the same reference numerals in each drawing indicate the same parts or portions, the explanation of the following parts will be omitted.

Fig. 1 is a partial front view showing an example of the lower part of the screw shaft of a conventional drilling machine.A shaft _3-1 is attached near the bottom of the screw shaft 1 wrapped around the screw 2 that carries the excavated earth to the ground. 3 _-2 , are located on the front and opposite sides of the figure, and movable cutting blades 4 _-1 and 4 _-2 are fitted so as to be rotatable about the axis, respectively, and the movable cutting blades are rotated by springs (not shown). It is assumed that the force is applied so that the tip diameter is minimized.

If you press down the screw shaft 1 with a strong force in the axial direction while drilling while rotating the screw shaft 1 in the right direction when looking at it from above, the movable cutting blade 4 _-
The tips of ₁ and _4-2 are pushed and expanded left and right as shown by the arrows and two-dot chain lines in the figure, creating a large diameter hole. Furthermore, when the downward force of the screw shaft 1 is weakened, it is returned by the spring and the diameter of the tip of the movable cutting blade is reduced. However, in this example, the amount of expansion of the tip of the movable cutting blade cannot be determined because it is affected not only by the downward force of the screw shaft but also by the condition of the earth and sand during excavation, and the amount of expansion can be detected on the ground. There are disadvantages such as difficulty in installing the device. The hollow hole 1a shown in the dotted line in the screw shaft 1 and the hole 1b at its bottom are used to feed fluids such as water and air so that the excavated earth and sand can be easily transported to the ground by the screw 2, This is for injecting a hardening material such as cement milk into the bottom of the hole.

FIG. 2 is a plan view of another conventional example of the lower part of the screw shaft cut in the direction perpendicular to the axis, and the screw 2 is not shown because it would be complicated. In this example, movable cutting blades _7-1 , ₇ are rotatably attached to shafts 6-1, _6-2 attached to brackets _5-1 , _5-2 protruding near the bottom of the screw shaft 1.
_-2 is fitted. Therefore, when the screw shaft 1 is rotated to the left in the figure, the diameter of the tip of the movable cutting blade is enlarged due to the digging resistance as shown by the arrow and the two-dot chain line in the figure, and the screw shaft 1 is rotated to the right. When this happens, the diameter of the tip of the movable cutting blade is reduced due to the excavation resistance, as shown by the solid line.
In any case, it is not possible to arbitrarily and accurately adjust the amount of expansion of the movable cutting blade, or it is difficult to install an indicating device to detect the amount of expansion on the ground.
The return operation of the enlarged movable cutting blade is uncertain, and even if an indicating device can be attached, screw shafts and rods for enlarging or indicating devices must be added as appropriate to drill deeply, so The structure of this joint part had many drawbacks, including unreliability in terms of operation, strength, and accuracy.

In contrast, recent efforts have been made to increase the outer diameter of the tip of the movable cutting blade using the vertical movement and link mechanism of the cutting blade operating ring attached to the lower end of the rod of the feed screw, which is installed concentrically near the bottom of the screw shaft. At the same time, an expanding rod is connected to the top of the feed screw and protrudes to the top of the main body of the drilling machine, and the rotation of the expanding rod is stopped by a rod fixing device such as a hydraulic cylinder fixed to the main body. By causing rotation relative to the screw shaft, the cutting blade operating ring is moved up and down with respect to the screw shaft to expand or reduce the outer diameter of the movable cutting blade, and the expanding rod and the screw The expansion amount of the movable cutting blade can be accurately detected on the ground by detecting the relative axial displacement between the shafts using the expansion detection mechanism provided on the main body and detecting the outer diameter of the tip of the movable cutting blade. Returning is also secure by reversing the screw shaft and locking the expansion rod, and adding screw shafts and expansion rods can be done using prismatic socket joints or key connections, making it easy to operate. A highly accurate and reliable earth auger magnifying device (patent application 118838/1983) was developed. This will be explained with reference to FIG.

This figure is an explanatory axial cross-sectional view of such an earth auger enlarging device.
Several brackets _23-1 and _23-2 are made to protrude,
Shafts 24 _-1 , 24 attached to the tips of the brackets
_-2 , lower the movable cutting blades 25 _-1 and 25 _-2 rotatably. On the other hand, a lower feed rod 26a and an upper feed rod 26b are extended to a feed screw 26 which is screwed into a female feed screw 21a provided in the axial direction of the lower inner hole of the screw shaft, and a hollow hole 26 is formed in the axial center.
c is passing through. A cutting blade operating ring 28 is rotatably fitted to the lower end of the lower feed rod 26a via a thrust bearing 27 with its axial position being held down.
5 _-1 , 25 _-2 and the same number of brackets 29 _-1 , 29
_-2 is projected and pin-connected between the movable cutting blades 25 _-1 and 25 _-2 via links 30 _-1 and 30 _-2 . Note that an appropriate number of fixed cutting blades 35 _-1 and 35 _-2 are attached to the bottom of the cutting blade operating ring as necessary. On the other hand, on the bottom screw shaft 21 is an intermediate screw shaft (not shown in the figure) on which the outer circumferential screw is wrapped via a hexagonal socket joint 33 for the purpose of transmitting rotational force and a retaining pin 34 driven into the diagonal position of the hexagonal socket joint 33. (Although it is not included, it may be added as appropriate depending on the depth of the hole.) Alternatively, a top screw shaft 31 with a screw 32 wrapped around the outer periphery is connected. On the other hand, the top screw shaft 31 has a hollow hole 31a in its axial center, into which a top expansion rod 36 is inserted, and is connected to the top feed rod 26b via a key 37 for the purpose of rotation transmission. connected. A hollow hole 36a is also provided at the axial center of the upper feed rod 26b, and a gasket 38 is provided to connect with the hollow hole 26c and to fluidly disconnect it from the outside. (Although not shown, intermediate enlarging rods are added as appropriate depending on the depth of the hole to be drilled.) Next, a gear 31b is integrally attached to the top of the top screw shaft 31, and a tapered roller is attached. The gear 3 is rotatably supported by the case-like earth auger main body 40 via a bearing 39 and a thrust bearing 41, and is further attached to the shafts of reducer-equipped electric motors 42 _-1 and 42 _-2 mounted on the main body 40.
It is driven by pinions 43 _-1 and 43 _-2 that mesh with 1b. On the other hand, the top enlargement rod 36 is attached to the main body 40.
A ratchet wheel 44 with a groove 44a cut on the outer periphery is integrally provided on the upper part of the protruding part, and extends further upwards to have a swivel joint 45 at the top end, which connects the perforated hole from the outside through the hollow holes 36a and 26c. It is used for purposes such as sending air, water, cement milk, etc. to the bottom of the hole to make it easier to transport excavated earth and sand to the ground using screws 22 and 32, and injecting hardening material at the bottom of the hole. On the other hand, the upper brackets 46 _-1 and 46 _-2 of the main body 40 have hydraulic cylinders 47 _-1 and 47 -2 having rods 48 _-1 and _{48 -2 from} which the rods 48 _-1 and 48 _-2 are pushed out. and said pawl 4
It is mounted at a position where it engages with the groove 44a of No. 4. Further, a detection wheel 50 is mounted on the upper part of the stopper wheel 44 via a thrust bearing 49, and is further engaged with a bracket _46-1 via a feather key 51, and a fixed resistor 53 is mounted on the bracket _46-1 .
A main body of a potentiometer 52 having a built-in body is attached, and a sliding piece 54 of the potentiometer 52 is attached to the detection wheel 50.

With this configuration, the feed screw 2 is provided in the axial direction of the shaft center of the bottom screw shaft of the drilling machine.
The vertical movement of the cutting blade operating ring 28 rotatably supported by the lower feed rod 26a of No. 6 expands and contracts the tips of the movable cutting blades 25 _-1 and 25 _-2 via the link mechanism, and the feed screw 26 The top enlargement rod 36 connected to the top feed rod 26b is projected above the ground and stopped by a stop mechanism as appropriate to provide a relative rotational displacement between the feed screw 26 and the bottom screw shaft 21. By detecting this relative rotational displacement or the relative axial displacement caused by the feed screw at the same time as the operation, the amount of expansion of the movable cutting edge detected on the ground can be accurately controlled. It is easy to add rods, and the earth auger expansion device is highly reliable in terms of operation, strength, and precision.

However, such a magnifying device has the following drawbacks due to its structure.

Since the cutting blade operating ring, expansion link, lower feed screw rod, etc. come into direct contact with the excavated ground and earth and sand during excavation, they are not only susceptible to damage, but also dirt accumulates between the cutting blade operating ring and the bottom screw shaft. Therefore, the enlargement operation may not be performed properly. In order to absorb the relative rotational displacement that occurs between the screw shaft and the feed screw rod during expansion operation,
A large thrust bearing must be provided to support the dead weight of the entire device, and an associated mechanism for enlarging the movable cutting edge by relative axial displacement of the lower feed rod by the feed screw in the bottom screw shaft. That is, since the lower feed rod, large thrust bearing, operating ring, etc. have to be exposed outside the bottom screw shaft, they are susceptible to damage from earth and sand as described above.

The present invention is an enlarged earth auger that solves these problems by expanding the movable cutting edge by using a hydraulic device and oil passage installed inside the bottom screw shaft to compensate for the axial displacement of the rod by the feed screw. The purpose is to provide equipment.

Next, the present invention will be described with reference to an illustrated embodiment. Components with the same reference numerals in FIG. 3 indicate the same parts or portions, and descriptions of components having the same functions and configurations as in FIG. 3 will be omitted.

Drive shaft 60 and intermediate screw shaft 6
1 and the enlargement mechanism shaft 62 are connected to each other by a rotation transmission joint, and an auger head 63 is further connected to the tip of the enlargement mechanism shaft 62. Brackets 23 _-1 and 23 _-2 are protruded from the bottom of the enlargement mechanism shaft 62, and shafts 24 _-1 and 24 _-2 attached to the tips thereof have rotatable movable cutting blades 25 _-1 and 25 _-2 . are doing. One end of these movable cutting blades 25 _-1 and 25 _-2 are each connected to a link 30 _-
Passive cylinders 64 _-1 , 64 _-2 via ₁ , 30 _-2
Connected to the piston rod. These passive cylinders 64 _-1 and 64 _-2 are thin tubes provided in the expansion mechanism shaft, two each to the upper and lower chambers of each piston of the driving cylinder 65 provided at the axial center of the expansion mechanism shaft 62. 66 _-1 , 67 _-1 and 66 _-2 ,
Connected by 67 _-2 . The piston 68 of this driving cylinder is formed at the tip of a feed rod 26a that is provided within the mechanism shaft 62 and is rotatable about its axis. A feed screw 26 is provided on the outer periphery of the central portion of the feed rod 26a, and the feed rod 26a is rotated by mutual rotation with the feed screw 21a provided at the axial center of the enlargement mechanism shaft. The driving cylinder piston 68 moves upward with respect to the shaft 62, compressing the liquid filling the cylinder, and the increased pressure is applied to the piston rod side of the passive cylinders _64-1 and _64-2 . Generates a thrust that is transmitted through the capillary and acts upwards. Therefore, the above-mentioned movable cutting blades 25 _-1 and 25 _-2
rotates in the outer circumferential direction around shafts _24-1 and _24-2 , and can obtain the required expansion amount larger than the screw diameter of the auger head. At this time, although not shown, it goes without saying that a phase correction valve is provided so that the phase between the driving cylinder and the passive cylinder can be constantly adjusted. The feed rod 26a is connected to a drive rod 69 and an intermediate rod 70 through rotation transmission joints, and when the movable cutting edge is expanded, the worm gear 72 of the expansion mechanism drive section 71 is rotated to act as a speed reducer. Electric motor 42 _-1
The enlargement mechanism shaft 62 is driven by
The movable cutting edges 25 _-1 and 25 _-2 can be enlarged by causing a rotational displacement between them as described above. Here is the screw diameter of the auger head 63.
It is made larger than the effective diameter of the expanding device including the movable cutting blades 25 _-1 and 25 _-2 and the passive cylinder during contraction.

As described above, the present invention provides a hydraulic device and a thin tube inside the shaft of the expanding mechanism section, and uses the axial displacement of the rod by the feed screw as an expanding thrust, that is, an expanding force generating section and a driving section that expands the cutting edge. The driving cylinder can be separated and installed in any position, and the driving cylinder is housed in a shaft with sufficient strength, and the enlarged driving passive cylinder is placed outside the shaft at an appropriate position, and the gap between them is a thin tube installed inside the shaft. By communicating with each other, there is no need for a large thrust bearing to absorb the relative rotational displacement of the conventional hydraulic device, and there is no need to make the tip of the shaft unnecessarily large, and there is no need for damage to the expansion mechanism. can also be prevented. In addition to the cement milk passage 36a, a necessary air passage 73 is also provided inside the rod to facilitate the work.

[Brief explanation of the drawing]

Fig. 1 is a partial front view showing an example of the vicinity of the lower part of the screw shaft of a conventional earth auger, Fig. 2 is a plan view of the lower part of the screw shaft of another conventional example taken in the direction perpendicular to the axis, and Fig. 3 is FIG. 4 is an explanatory axial cross-sectional view of another conventional example, and FIG. 4 is an explanatory cross-sectional view of a main part of an embodiment of the present invention. 22... Screw, 25 _-1 , 25 _-2 ... Movable cutting blade, 26... Feed screw, 26a... Feed rod, 62... Enlargement mechanism shaft, 63... Auger head, 64 _-1 , 64 _-2 ...Passive cylinder, 6
5...Motive cylinder.

Claims (1)

[Scope of utility model registration request] In an earth auger expansion device that enlarges or contracts a movable cutting edge provided at the bottom of a screw shaft with an auger wrapped around the outer periphery via a link, an intermediate screw shaft driven by a driving screw shaft is used. an auger head connected to the tip of an enlargement mechanism shaft connected to the auger head; a driving rod passing through the shaft center of the drive screw shaft and the intermediate screw shaft and rotatably connected to each other; and the intermediate rod a feed rod rotatably provided at the axial center of the enlargement mechanism shaft; the feed rod has a feed screw corresponding to the female thread of the enlargement mechanism shaft; and the feed rod moves in the axial direction by rotation of the feed screw. a driving cylinder provided within the expansion mechanism shaft having a piston formed at the tip of the rod; and a driving cylinder installed on the outer periphery of the expansion mechanism shaft and provided within the driving cylinder and the expansion mechanism shaft. It is equipped with a passive cylinder that communicates with a thin tube, and a movable cutting blade that is expanded and contracted by the rotational drive of the feed rod through a link connected to the piston rod of the passive cylinder, so that the cutting blade can be reduced within the diameter of the auger head. An earth auger expansion device characterized by housing a movable cutting blade and a passive cylinder.