JPH0849485A - Torque limiter for construction machine - Google Patents

Abstract

PURPOSE:To provide a torque limiter for a construction machine devised to protect a tool. CONSTITUTION:Engagement grooves 58, 60 are formed on a cylindrical sliding contact surface around a rotation center formed on a case member 30 installed on a grip mechanism 15 to be integrally roratably engaged with the interion wall of a casing tube 10 as its center and a piston 44 energized to a main body member 36 installed on a drilling bucket 68 by springs 48, 50. The grip mechanism 15 and the drilling bucket 68 are connected to each other through an engagement mechanism 63 free to release engagement with the piston 44 by inserting a rolling element 62 into the engagement grooves 58, 60 and sliding the piston 44 against energizing force of the springs 48, 50 by increase of torque.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a torque limiter for a construction machine, which limits torque transmission when a rotating tool is overloaded.

[0002]

2. Description of the Related Art Conventionally, as a method for excavating a pile hole,
For example, as disclosed in Japanese Utility Model Laid-Open No. 6-43090, a tubular member having a lower end to which an auger drill is detachably attached is slidably attached to a shaft suspended in a casing tube so as to be vertically movable. Connect the shaft with the shaft downward from the center and the link between the grip member and the tubular member with the link upward from the center to the outside, and expand the grip member to the inner wall of the casing tube. There is known a device for engaging and excavating the casing tube and the auger drill so as to rotate integrally.

[0003]

However, in such a conventional one, for example, when the drill bit attached to the tip of the auger drill hits hard rock or rock,
Sometimes the drill bit is missing, in which case
Once, the auger drill must be lifted to the ground, the excavation bit replaced, and the excavation repeated. From the ground, in order to monitor whether the excavation bit has hit hard rock, etc., the hydraulic oil pressure supplied to the hydraulic motor that drives the casing tube is detected, and after confirming the pressure increase, stop the hydraulic motor. However, it was not in time to prevent damage and could not adequately protect the drill bit. Also, not limited to the auger drill, other tools, for example,
The same applies to an excavation bucket and the like, and there is a problem that the tool may not be protected from damage.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a torque limiter for a construction machine, which aims to solve the above problems and protects a tool.

[0005]

In order to achieve such an object, the present invention has the following constitution as means for solving the problem. That is, the tool of the construction machine that transmits the rotation of the drive source to the tool via the rotation transmission mechanism and the rotation transmission mechanism are rotatably connected to each other, and one of the tool and the rotation transmission mechanism is biased by A piston that is biased by and is slidably supported is provided, and the piston and the other of the tool and the rotation transmission mechanism are slid against the biasing force of the biasing member by increasing the torque. That is, the construction of the torque limiter for a construction machine is characterized in that it is connected through a meshing mechanism capable of releasing the engagement with the piston.

Further, the meshing mechanism has rolling elements inserted in meshing grooves formed respectively on the tip of the piston and a cylindrical sliding contact surface centered on the rotation center formed on the other side. Alternatively, the rolling element may be configured to be slidable from one of the engagement grooves by sliding the piston against the urging force of the urging member due to an increase in torque.

Further, the rotation transmission mechanism includes a casing tube and a grip mechanism that is hung inside the casing tube to expand and engage with the inner wall of the casing tube so as to rotate integrally with the casing tube. The tool may be rotatably supported.

[0008]

In the construction machine torque limiter having the above structure, when the drive source is rotationally driven, the rotation transmission mechanism transmits the rotation to the tool through the meshing mechanism. And
When the torque applied to the tool increases, the piston slides against the urging force of the urging member to release the engagement between the rotation transmission mechanism and the tool, and the rotation of the drive source is not transmitted to the tool. Is protected.

Further, in the case where the meshing mechanism is provided with a rolling element, the piston slides against the urging force of the urging member due to an increase in torque, the rolling element is disengaged from the meshing groove, and the engagement is released. It Then, due to the rotation of the rotation transmission mechanism, the rolling elements are transmitted along the cylindrical sliding contact surface and are fitted into the engagement groove again, and when the torque is reduced, the rotation of the rotation transmission mechanism passes through the engagement mechanism. Is transmitted to the tool, and the engagement is restored.

When the rotation transmission mechanism includes the casing tube and the grip mechanism, when the casing tube is rotated, the tool is rotated via the grip mechanism and the meshing mechanism.

[0011]

Embodiments of the present invention will now be described in detail with reference to the drawings. As shown in FIG. 2, reference numeral 1 is a rotary pushing mechanism, in which a lifting cylinder 4 for lifting the lifting frame 3 is assembled on a base frame 2 which is held in a horizontal state, and a ring is mounted on the lifting frame 3 via a bearing 5. The rotating member 6 is supported in a rotatable manner. A gear 7 is formed on the outer periphery of the rotary member 6, and a drive gear 8 a fixed to the rotary shaft of a hydraulic motor 8 provided on the elevating frame 3 and a gear 7 are meshed with each other via an idle gear 9 to form a hydraulic motor 8. Is configured to rotate the rotating member 6.

A taper hole 11 through which the casing tube 10 can be inserted is formed on the inner circumference of the rotary member 6, and the taper hole 11 is formed so as to reduce its diameter downward. A bracket 13a that is moved up and down by a chuck cylinder 12 arranged on the elevating frame 3 is provided above the rotating member 6, and the rotating frame 1 is interposed between the bracket 13a and the rotating member 6 via a bearing 13b.
3c is supported and arranged so as to move up and down together with the bracket 13a. A wedge-shaped chuck member 14 suspended from the rotating frame 13c is inserted between the tapered hole 11 and the casing tube 10.

A grip mechanism 15 is suspended in the casing tube 10 by a crane (not shown).
The grip mechanism 15 includes a shaft 19 suspended from a wire rope 18 of a crane via a swivel joint 17.
A tubular member 20 slidably mounted on the shaft 19 in the vertical direction, and a plurality of grip members 22 arranged along the inner circumference of the casing tube 10.

Upper flange 1 fixed to shaft 19
The weight 23 is mounted on the shaft 9a, and the shaft 19
A spring 24 is compressed and interposed between and the cylindrical member 20. The upper flange 19a and the grip member 22 are connected by a link 25 swingably supported at both ends so that the grip member 22 is expanded by the downward movement of the upper flange 19a. The tubular member 20 and the grip member 22 are connected by a pair of upper and lower links 26 and 27 so that the upward movement of the tubular member 20 expands the grip member 22.

In this embodiment, the casing tube 1
0 and the grip mechanism 15 constitute a rotation transmission mechanism 28. The rotation transmission mechanism 28 is not limited to this, and may be a kelly bar or the like by a reverse construction method or an earth drill construction method. The flange 31 of the case member 30 is attached to the lower end flange 20a of the tubular member 20, and the case member 30 is projected downwardly and coaxially with the tubular member 20, as shown in FIGS. A shaft portion 32 is formed. A cylindrical sliding contact surface 34 is formed on the inner periphery of the case member 30 concentrically with the shaft portion 32.

The shaft portion 32 has an insertion hole 38 formed in a body member 36 housed in a space surrounded by the sliding contact surface 34.
The ring member 64 is rotatably inserted into the case member 30 and is fixed to the case member 30 to prevent the main body member 36 from coming off. Further, the case member 30 and the body member 36
A thrust bearing 40 is interposed between and. Sliding holes 42 are formed in the body member 36 in the radial direction of the shaft portion 32, and in the present embodiment, four sliding holes 42 (only a part of which are shown) are formed at equal intervals. Pistons 44 are slidably inserted into the holes 42, respectively.

From the shaft portion 32 side of the piston 44, the bottomed hole 4
6 is formed, and two springs 48 and 50 as biasing members are inserted into the bottomed hole 46. A flange 54 formed at the tip of a support shaft 52 protruding from the main body member 36 into the bottomed hole 46 is inserted into the bottomed hole 46, and is provided with a cap 56 fixed to the piston 44. The bottom hole 46 is closed, the piston 44 is radially urged by the urging force of the springs 48 and 50, and the protrusion is restricted.

Four interlocking grooves 58 are formed at equal intervals on the sliding contact surface 34, and interlocking grooves 60 are formed at the tip of each piston 44. In this embodiment, the two engaging grooves 58, 60 are recessed in a direction parallel to the shaft portion 32 and are formed in an arc shape having the same radius.
The engagement groove 60 on the piston 44 side is formed deeper. Then, a cylindrical rolling element 62 is inserted into both the engaging grooves 58 and 60.

In this embodiment, the two engaging grooves 58, 6 are
The 0 and the rolling element 62 form a meshing mechanism 63. Although the meshing mechanism 63 uses the rolling element 62, a semi-cylindrical projection corresponding to the rolling element 62 that can be inserted into the meshing groove 58 may be formed at the tip of the piston 44 without using the rolling element 62. Alternatively, the sliding contact surface 34 may be formed with a protrusion that can be inserted into the engagement groove 60 of the piston 44. Further, the case member 30 has a piston 44.
Can be slidably supported, and a sliding contact surface 34 is formed on the main body member 36.

The body member 36 has a flange 6 on the lower side thereof.
6 is formed, and a flange 70 of an excavation bucket 68 as a tool is fixed to the flange 66. The excavation bucket 68 is capable of excavating with a plurality of excavation bits 72 attached to the tip and storing the excavated earth and sand inside, and after pulling it to the ground, the lid 74 is opened to remove the earth and sand inside. It has a well-known structure that can be discharged. The tool attached to the flange 66 is not limited to the excavation bucket 68, and an auger drill or the like can be used.

Next, the operation of the construction machine torque limiter of this embodiment will be described. First, the casing tube 10 is inserted and the chuck cylinder 12 is driven to lower the bracket 13a. As a result, the chuck member 14 is inserted between the tapered hole 11 and the casing tube 10 via the bearing 13b and the rotating frame 13c, and the chuck member 14 fastens the rotating member 6 and the casing tube 10.

When the hydraulic motor 8 is rotationally driven, the rotary member 6 is rotated via the drive gear 8a and the idle gear 9, and the casing tube 10 is rotated together with the rotation of the rotary member 6. Further, the elevating cylinder 4 is driven to lower the elevating frame 3, and the casing tube 10 is pushed into the ground through the rotating member 6, the chuck member 14, and the like.

Further, the grip mechanism 15 is suspended from the wire rope 18 of the crane, and the excavation bucket 68 is inserted into the casing tube 10. When the excavation bucket 68 hits the bottom, the shaft 19 descends together with the upper flange 19a due to the weight of the weight 23 and the urging force of the spring 24. As a result, the grip member 22 is expanded through the link 25, and the grip member 22 is pressed against the inner circumference of the casing tube 10, so that the grip mechanism 15
And the casing tube 10 are engaged.

As a result, the grip mechanism 15 rotates with the rotation of the casing tube 10, and the rotation of the hydraulic motor 8 is transmitted to the case member 30 via the casing tube 10 and the grip mechanism 15. The rotation of the case member 30 is transmitted to the main body member 36 via the rolling elements 62 and the pistons 44 inserted in the both engaging grooves 58 and 60, and is transmitted from the main body member 36 to the excavation bucket 68.

Therefore, the excavation bit 7 of the excavation bucket 68
2 excavated, and the excavated earth and sand is excavated by the excavation bucket 68.
Taken in. Then, when the excavating bit 72 hits a hard rock or a boulder, the torque of the hydraulic motor 8 increases. When the torque increases, the engagement groove 58 on the sliding contact surface 34 side increases the acting force for sliding the piston 44 against the biasing force of the springs 48, 50 via the rolling element 62. When this acting force exceeds the urging force, the piston 4
4 is slid against the urging force of the springs 48 and 50, and the engagement groove 60 on the piston 44 side is deeper, so that the rolling element 62 separates from the engagement groove 58 on the sliding contact surface 34 side. Therefore, the rotation of the grip mechanism 15 is not transmitted to the excavation bucket 68.

The rolling element 62 rolls on the sliding contact surface 34,
Although it enters the meshing groove 58 on the next sliding contact surface 34, when the torque is large, the rolling element 62 disengages from the meshing groove 58 and the excavation bucket 68 does not rotate. The spring 48,
By changing the biasing force of 50, the magnitude of the torque when the rolling element 62 is disengaged from the engagement groove 58 can be changed.

When the pushing of the casing tube 10 by the elevating cylinder 4 is stopped or the pushing amount per one rotation is reduced to reduce the excavation torque, the rolling element 6
2 rolls on the sliding contact surface 34 and enters the engaging groove 58. Then, it does not come off from the engaging groove 58,
The rotation of the grip mechanism 15 causes the case member 30, the engagement groove 58, the rolling element 62, the engagement groove 60, the piston 44,
It is transmitted to the excavation bucket 68 via the main body member 36, and the rotation automatically returns.

The diameter of the casing tube 10 is 800 to
Since the casing tube 10, the grip mechanism 15, etc. having a large weight are rotating during excavation, the casing tube 10, the casing tube 10, etc. In some cases, the rotating torque due to the inertia of the grip mechanism 15 or the like is applied to the excavation bit 72, and the damage of the excavation bit 72 cannot be effectively prevented.

By providing between the grip mechanism 15 and the excavation bucket 68, when the torque increases, the rotational torque of the grip mechanism 15 is not transmitted to the excavation bucket 68, so that it is affected by the inertia of the rotation transmission mechanism 28. Therefore, the rotation of the excavation bucket 68 is stopped, and the excavation bit 72 and the like can be effectively prevented from being damaged.

The present invention is not limited to the embodiments described above, and can be carried out in various modes without departing from the scope of the present invention.

[0031]

As described above in detail, in the torque limiter for a construction machine of the present invention, when the torque increases, the engagement mechanism releases the engagement with the piston and the rotation of the rotation transmission mechanism is not transmitted to the tool. Therefore, even if the inertia of the rotation transmission mechanism is large, the tool can be effectively prevented from being damaged. Further, in the case where the meshing mechanism has the meshing groove and the rolling element, when the torque decreases, the rolling element re-enters the meshing groove and the engagement is automatically restored.

[Brief description of drawings]

FIG. 1 is a sectional view of a torque limiter for a construction machine as an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a construction machine using the torque limiter for construction machine of the present embodiment.

3 is a cross-sectional view taken along the line AA in FIG.

[Explanation of symbols]

1 ... Rotary pushing mechanism 8 ... Hydraulic motor 10 ...
Casing tube 15 ... Grip mechanism 28 ... Rotation transmission mechanism 30 ...
Case member 34 ... Sliding contact surface 36 ... Main body member 44 ...
Pistons 58, 60 ... Meshing groove 62 ... Rolling element 63 ...
Interlocking mechanism 68 ... Excavation bucket 72 ... Excavation bit

Claims (3)

[Claims] 1. A tool of a construction machine, which transmits the rotation of a drive source to a tool via a rotation transmission mechanism, and the rotation transmission mechanism are rotatably connected to each other, and one of the tool and the rotation transmission mechanism is connected to the tool. A piston urged by an urging member and slidably supported is provided, and the piston and the other of the tool and the rotation transmission mechanism are opposed to the urging force of the urging member by increasing the torque. A torque limiter for a construction machine, characterized in that the torque limiter is slidably slid to be coupled with the piston via an engagement mechanism capable of releasing the engagement. 2. The meshing mechanism has rolling elements inserted in meshing grooves formed respectively on a tip of the piston and a cylindrical sliding contact surface centered on a rotation center formed on the other side. The construction machine according to claim 1, wherein the rolling element is formed so as to be disengaged from one of the engagement grooves by sliding the piston against the urging force of the urging member due to an increase in torque. Torque limiter. 3. The rotation transmission mechanism includes a casing tube, and a grip mechanism that is hung inside the casing tube to expand and engage with the inner wall of the casing tube so as to rotate integrally with the casing tube. The torque limiter for a construction machine according to claim 1 or 2, wherein the tool is rotatably supported.