JPH0437725Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to an automatic tightening device for a fastener that fixes the swing circle of a power swivel.

[Conventional technology]

In a general power swivel, the upper swing body is attached to the lower body with the suspension so that it can freely swing via a swing circle, and the lower body is fixed to the inner race of the swing circle by a number of fasteners screwed in from below. ing.

Furthermore, conventionally, a tightening device employing a nut runner has been used to tighten the above-mentioned fixing device, but the conventional tightening device has a gate-shaped frame provided above the swing circle, and this frame has an indexing device attached to it. A motor is installed, and the nut runner is indexed to the tightening position by rotating the tightening device main body via an indexing gear provided at the center of the swing circle.

[The problem that the idea attempts to solve]

Conventional tightening devices require a frame to support the indexing motor, an indexing gear to transmit the rotation of the motor to the main body, and the indexing mechanism is large and complicated.

In addition, since the reaction force receiver that receives the tightening reaction force is in contact with the member to be tightened, when the nut runner is indexed by rotating the main body, the reaction force receiver interferes with the rotation, making it impossible to index the nut runner smoothly. The tightening torque is detected on the nut runner side via a gear that transmits the rotation of the bolt to the fixing tool.
There were also problems such as poor detection accuracy.

This idea was made to improve the above-mentioned problems. It does not require a complicated indexing mechanism, the reaction force receiver during indexing of the nut runner does not interfere with the rotation of the main body, and the tightening torque is also reduced. It is an object of the present invention to provide an automatic fastener tightening device that can accurately detect fasteners.

[Means and actions for solving problems]

In order to achieve the above object, this invention provides a main body on the swing circle placed on the lower body of the power shovel so as to cross this.
The main body is fixed to the outer race of the swing circle, and two electric nut runners are provided at both ends of the main body, which are pivotally connected by shaft rods provided on the center line of the fastener to be tightened. An index gear meshes with a ring gear provided on the inner race of the swing circle, and by rotating this index gear with a servo motor, the main body is rotated together with the outer race, and the soles of the electric nut runners provided at both ends of the main body are moved into the inner race. In addition to providing an indexing mechanism for positioning the race bottle hole, the gear case of the reducer that transmits the rotation of the electric nut runner to the socket is biased by an elastic body in a direction away from the lower vehicle body, and when the fastener is tightened, it resists the tightening. A reaction force receiver is provided to support the reaction force of contacting and tightening the lower body by force, and a torque detector is installed on this reaction force receiver to detect the tightening torque.A drive mechanism for indexing and rotating the main body is installed on the reaction force receiver. Since there is no need to provide a separate external device, the indexing mechanism can be simplified.

Furthermore, since the reaction force receiver is separated from the lower vehicle body during index rotation, the main body can be rotated smoothly, and since a torque detector is provided on the reaction force receiver, the tightening torque can be accurately detected.

〔Example〕

One embodiment of this invention will be described in detail with reference to the drawings. In the figure, 1 is the main body of this device, which is mounted horizontally on the outer race 3a of the swing circle 3 placed on the lower body 2 of the power shovel. It's getting old. The main body 1 has an elongated box shape, and has shaft rods 4 at both ends that serve as the center of the equalizer.
An electric nut runner 5 is pivotally mounted via the shaft lever 4 so as to be rotatable in the direction of the arrow a-b.
Further, the center of the shaft rod 4 is located on the center line of a bolt hole provided in an inner race (not shown) of the swing circle 3, and
By rotating the index gear 6 that meshes with the ring gear (fixed to the inner race side) of the swing circle 3 by the servo motor 15 placed above, the main body 1 rotates together with the outer race 3a of the swing circle 3, and the shaft rod 4 The center of the nut runner 5, that is, the equalization center of the electric nut runner 5, can be positioned at the center of the bolt hole of the inner race. An elastic body 7 is provided between the main body 1 and the electric nut runner 5, and elastically supports the rotation of the electric nut runner 5, and also controls the rotation of the AC servo motor 5a provided in the electric nut runner 5. Spline shaft 5b
The signal is transmitted to the input gear 8a of the speed reducer 8 via. The reduction gear 8 is a lifting cylinder 9
A plurality of reduction gears 8c are housed in the gear case 8b, and the output gear 8d of the reduction gear 8c has its center located below the swing circle 3 at the center of the shaft rod 4. A socket 11 for tightening the fastener 10 is attached upward to the center of the output gear 8d.

On the other hand, a reaction force receiver 12 is provided protruding from the side surface of each gear case 8b of the reduction gear 8. The distal ends of these reaction force receivers 12 extend toward the lower vehicle body 2, and the distal ends are slightly separated from the lower vehicle body 2.
When the fastener is tightened, it comes into contact with the lower vehicle body 2 to support the tightening reaction force.

Further, the reaction force receiver 12 is provided with a torque detector 14 . The torque detector 14 is configured such that a strain gauge and a resistor are bridge-connected as shown in FIG. 4, and the tightening torque is detected from the distortion of the reaction force receiver 12. The signal is amplified by an amplifier 16 and output to the electric nut runner 5, and the electric nut runner 5 is stopped when the tightening torque reaches a predetermined value.

[Effect of idea]

Since this invention has been described in detail above, the rotation of the servo motor 15 causes the index gear 6 to mesh with the ring gear 3b of the swing circle 3.
When rotated, the main body 1 attached to the outer race a rotates together with the outer race 3a, and the bolt holes of the inner race and the socket 11 can be positioned quickly and accurately. Does not require an ejection mechanism, and
The work of tightening the fastener 10 can be done efficiently in a short time by the two electric nut runners 5.

In addition, when tightening the fastening tool, the reaction force receiver 12 supporting the reaction force is urged in the direction away from the lower vehicle body 2 by the elastic body 7, so that when the electric nut runner 5 is indexed, the reaction force receiver 12 is There is no risk of interfering with the rotation of the fastener, and when the fastener is tightened, the electric nut runner 5 rotates around the shaft rod 4 due to the tightening reaction force because it comes into contact with the lower vehicle body 2 and supports the tightening reaction force. It will never happen.

Moreover, since the torque detector 14 is provided on the reaction force receiver 12, the detection accuracy is improved compared to the conventional detection via the gearbox 8b, so the fastener 10 can be tightened with a predetermined torque. It becomes like this.

[Brief explanation of drawings]

The drawings show one embodiment of this invention, and Fig. 1 is a perspective view, Fig. 2 is a sectional view of the electric nut runner and reducer, Fig. 3 is an explanatory diagram of the torque detector, and Fig. 4 is a circuit diagram of the same. be. 1 is the main body, 2 is the lower body, 3 is the swing circle, 3a is the outer race, 3b is the ring gear, 4
1 is a shaft rod, 5 is an electric nut runner, 6 is an index gear, 8 is a reducer, 8b is a gear case, 10 is a fixture, 11 is a socket, 12 is a reaction force receiver, 14
is a torque detector, and 15 is a servo motor.

Claims (1)

[Scope of utility model registration request] A main body 1 is provided on the swing circle 3 placed on the lower body 2 of the power shovel so as to cross the swing circle 3, and the main body 1 is fixed to the outer race 3a of the swing circle 3. is provided with two electric nut runners 5 which are pivotally connected by a shaft 4 provided on the center line of the fastener 10 to be tightened, and the main body 1 is equipped with a ring gear 3b provided on the inner race of the swing circle 3. By engaging the index gear 6 and rotating the index gear 6 by the servo motor 15, the main body 1 is connected to the outer race 3a.
An indexing mechanism for positioning the socket 11 of the electric nut runner 5 provided at both ends of the main body 1 in the inner race bottle hole by rotating the nut runner 5 at the same time is provided. A reaction force receiver 12 is provided in the gear case 8b, which is biased by the elastic body 7 in a direction away from the lower vehicle body 2, and which supports the tightening reaction force by coming into contact with the lower vehicle body 2 due to the tightening reaction force when the fastener is tightened.
An automatic tightening device for fasteners, which is provided with a torque detector 14 for detecting tightening torque on the reaction force receiver 12.