JP2007024135A - Mechanism for conduction between rotating members - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To avoid the event that a bearing mounted between a drum shaft and a winch drum is rotated during the operation of a crane winch but electric resistance is increased between the drum shaft and the winch drum during rotation to cause hard electric conduction. <P>SOLUTION: On the outside face of the bearing 7, a conduction member 23 is provided for electric conduction between the outer and inner rings of the bearing which is mounted between the drum shaft 6 and the winch drum 8 of the crane winch 5. Thus, forcible condition is performed between the drum shaft 6 and the winch drum 8. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a conduction mechanism between rotating members, and more particularly to a conduction mechanism using a conduction member that electrically connects an outer ring and an inner ring of a bearing interposed between the rotating members.

The present invention will be described with reference to an example of a crane portion of an in-vehicle crane mounted on a vehicle such as a truck.
For example, as shown in FIG. 1, the hook 9 suspended from the distal end of the tip boom 22 on the distal end side of the telescopic crane boom 2 via the hoisting / lowering wire rope 10 is excessively wound. An overwind switch 14 for detection is provided. The overwind switch 14 is in a state where the contact is closed during crane operation, and is configured as a normally closed contact that is activated when the overwind switch 14 is activated when the overwind state is reached.

  As shown in FIG. 5, one terminal of the overwind switch 14 is connected to the positive side of a battery 19 provided in a vehicle such as a truck on which a crane is mounted via a cord reel 16, a slip ring 17, and a relay 18. The other terminal is grounded to the tip boom 22. The relay 18 is connected to the positive side of the battery 19 and one terminal of the alarm buzzer 20 through a normally closed contact, and the other terminal of the alarm buzzer 20 is grounded to the base of the crane. The negative side of the battery 19 is body-grounded to the chassis of a vehicle such as a truck on which a crane is mounted. The chassis and the crane base are electrically connected.

  As shown in FIG. 1, the ground line of the overwinding switch 14 is electrically connected to the negative side of the battery 19 via a telescopic crane boom 2, a column 1, a turning device 27, a base, a truck, and other vehicle chassis. The first path (hereinafter referred to as “boom ground path”), the wire socket 13 pivotally attached to the tip boom 22, the wire rope 10 for winding up and down, the winch drum 8, the bearing 7, the drum shaft 6, the column 1, the base And a second path (hereinafter referred to as a “winding up / down wire rope ground path”) that is conducted to the negative side of the battery 19 through a chassis such as a truck.

  In FIG. 5, the overwind alarm is activated when the crane switch is operated, the overwind switch 14 is inactive and the contact is closed, so that the contact of the relay 18 is open, and therefore the alarm buzzer 20 does not sound. However, when the overwind switch 14 is actuated, the contact is opened, whereby the contact of the relay 18 is closed and the alarm buzzer 20 sounds to notify the overwind state.

  In the first earth-to-boom ground path, the ground of the overwind switch 14 is connected to the negative side of the battery 19 via the crane boom 2 that expands and contracts. Depending on the telescopic state, the contact between the booms may become unstable. If the contact between the booms becomes unstable, the ground connection becomes unstable, and a malfunction such as issuing an over-winding alarm occurs even if the hook 9 is not in the over-winding state.

  The reason why the contact between the booms becomes unstable is usually made of a metal for establishing conduction with the proximal boom 21 on the outside on the proximal outer side surface of the distal boom 22 located between the adjacent booms. Although the side sliding plate 221 is attached, the metal side sliding plate 221 is intermittently brought into non-contact with the adjacent proximal boom 21 depending on the vibration and load applied when the crane boom 2 is extended and contracted. This is because conduction between the booms becomes unstable. An upper surface sliding plate 222 is attached to the outer side of the upper end of the inner end boom 22 and a lower surface sliding plate 211 is attached to the inner side of the lower end of the outer end boom 21. It is a resin sliding plate for reducing sliding resistance between the booms when expanding and contracting, and there is no conduction (see FIG. 2).

  There exists patent document 1 as what solved the problem of the earth path | route between 1st booms. In this method, the booms are forcibly brought into metal contact with each other to establish conduction between the booms. However, this method requires a metal conductive member for each boom stage number, which increases the number of parts and increases the cost, and handling the boom is troublesome.

Further, in the second wire rope ground path for winding up and down, the bearing 7 interposed between the winch drum 8 and the drum shaft 6 rotates during the winch operation, and the winch drum 8 and the drum are rotated during the rotation. The electrical resistance between the shaft 6 and the connection between the shaft 6 and the shaft 6 becomes difficult, and the grounding path of the winding switch 14 provided on the tip side of the boom is still unreliable.
JP 2004-250204 A

  In the present invention, the problem of the second wire rope ground path for winding up and down is caused by the rotation of the bearing 7 used for the rotating portion of the winch drum 8, so that the rotating contact portion of the bearing is forcibly conducted. Let us solve the above-mentioned problems.

  For this reason, the present invention forcibly conducts between the rotating members by interposing with the bearing a conducting member that electrically connects the outer ring and the inner ring of the bearing on the outer surface of the bearing interposed between the rotating members. The above-mentioned problem is solved by applying the conduction mechanism between the rotating members configured to be between the drum shaft of the winch and the winch drum, which is between the rotating members in the wire rope ground path for winding up and down described above. .

1. Since the continuity between the drum shaft 6 and the winch drum 8 in the winch 5 of the crane can be reliably performed, the grounding of the overwinding switch 14 attached to the tip of the boom is routed via the wire rope 10 for winding up and down. It is reliably connected to the base side of the crane, stable grounding can be ensured, and the malfunction of the overwind alarm can be eliminated.
2. When the bearing 7 is attached, it is possible to reliably ensure conduction at low cost regardless of the number of boom stages, by attaching only one conducting member to the outer surface of the bearing.
3. Even conventional cranes can be easily added without requiring special processing.

  FIG. 1 shows an outline of a crane to which the present invention is applied. A crane boom 2 is attached to a boom raising / lowering cylinder 3 at the tip of a column 1 which is rotatable with respect to a crane base (not shown) via a turning device 27. Is provided up and down freely. The crane boom 2 includes a proximal boom 21 and a distal boom 22 that is slidably inserted into the proximal boom 21, and the distal boom 22 extends and contracts with respect to the proximal boom 21 by the boom telescopic cylinder 4. It is configured freely.

  As shown in FIG. 3, the column 1 is provided with a winch 5 and a drum shaft 6, and a winch drum 8 is rotatably supported on the drum shaft 6 through a bearing 7. A wire rope 10 for winding up and down for winding up and down 9 is wound. The winch drum 8 is rotated by the rotation of the winch 5, and the wire rope 10 for winding up and down is fed out from the winch drum 8.

The other end of the hoisting / lowering wire rope 10 wound around the winch drum 8 is guided to the distal end side of the crane boom 2 and hooks 9 via a boom distal pulley 12 provided on the boom top 11 at the distal end portion of the distal boom 22. Is secured to a wire socket 13 that is pivotally attached to the boom top 11.
Therefore, if the winch 5 is operated to wind up, the winch drum 8 feeds the hoisting / lowering wire rope 10 and the hook 9 is wound up. And the hook 9 is unwound.

  An overwind switch 14 is attached to the boom top 11, and the overwind switch 14 is activated when an overweight 15 suspended from the overwind switch 14 comes into contact with the hook 9 as the hook 9 rises. It is supposed to be.

The over-winding alarm circuit of the present invention is shown in FIG.
The winding switch 14 is a normally closed contact, and is configured to be opened in a winding state. One terminal of the overwind switch 14 is connected to the positive side of the battery 19 via a cord reel 16 provided on the boom top 11, a slip ring 17 provided between the base of the crane and the column 1, and a relay 18. The other terminal is grounded to the boom top 11.

  The relay 18 is connected to the positive side of the battery 19 and one terminal of the alarm buzzer 20 via a normally closed contact, and the other terminal of the alarm buzzer 20 is grounded to the base of the crane. The negative side of the battery 19 is body-grounded to a chassis such as a truck on which a crane is mounted. Note that the chassis and the base are electrically connected.

The grounding of the overwind switch 14 to the boom top 11 includes a wire socket 13 pivoted on the boom top 11, a wire rope 10 for winding up and down, a winch drum 8, a bearing 7, a drum shaft 6, a column 1, a turning device 27, and a base. The chassis communicates with the negative side of the battery 19.
In this ground path, the conduction between the bearing outer ring 7b and the bearing inner ring 7a of the bearing 7 is not on a rolling member such as a bearing ball 7c between the bearing outer ring 7b and the bearing inner ring 7a, but on the outer surface of the bearing 7. The conducting member 23 provided is forcibly conducted. That is, as shown in FIG. 4, the conducting member 23 includes a ring portion 24 that contacts the outer surface of the bearing outer ring 7b and a tip portion provided at the tip of an extension portion 25 that extends inward from the ring portion 24. 26 is brought into contact with the outer surface of the bearing inner ring 7a so that the outer ring and the inner ring are electrically connected.
Since the conductive member 23 can be configured to be thin, when the bearing 7 is interposed between the drum shaft 6 and the winch drum 8, it can be easily inserted by press-fitting with the bearing 7.

It is the schematic which shows the upper part from the column of the crane which has an expansion-contraction type 2 step | paragraph boom. FIG. 2 is an AA cross-sectional enlarged view of FIG. 1. FIG. 2 is an enlarged cross-sectional view taken along the line BB in FIG. 1. FIG. 4 is an enlarged view taken along arrow C in FIG. 3. It is the schematic of the electric circuit of an overwind warning.

Explanation of symbols

1 Column 2 Crane Boom 3 Boom Lifting Cylinder 4 Boom Telescopic Cylinder 5 Winch 6 Drum Shaft 7 Bearing 7a Bearing Inner Ring 7b Bearing Outer Ring 7c Bearing Ball 8 Winch Drum 9 Hook 10 Winding Up and Down Wire Rope 11 Boom Top 12 Boom End Pulley 13 Wire Socket 14 Over-winding switch 15 Over-winding weight 16 Cord reel 17 Slip ring 18 Relay 19 Battery 20 Alarm buzzer 21 Base end boom 211 Lower surface sliding plate 22 Front end boom 221 Side surface sliding plate 222 Upper surface sliding plate 23 Conducting member 24 Ring part 25 Extension part 26 Tip part 27 Turning device

Claims (2)

The outer surface of the bearing interposed between the rotating members is configured such that a conductive member for electrically connecting the outer ring and the inner ring of the bearing is interposed with the bearing so as to forcibly connect the rotating members. A conduction mechanism between rotating members. 2. The conduction mechanism between rotating members according to claim 1, wherein the rotating member is between a drum shaft of a winch of the crane and a winch drum.

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