WO2000015912A2

WO2000015912A2 - Device for holding attachments in power excavators

Info

Publication number: WO2000015912A2
Application number: PCT/KR1999/000447
Authority: WO
Inventors: Chul Ho Han
Original assignee: Chul Ho Han
Priority date: 1998-09-15
Filing date: 1999-08-12
Publication date: 2000-03-23
Also published as: KR20000019841A; WO2000015912A3; KR100310003B1; AU5306899A

Abstract

A device for detachably holding an attachment, such as a bucket (12) or a breaker, to the outside end of an arm unit (15) in power excavators is disclosed. In the preferred embodiment, two sets of bolt hooks (13, 14) are provided on an attachment. The device also has a link unit (1), comprising fixed and movable holding bolts (3, 5) set in a link frame (2). The attachment is mounted to the outside end of a main arm of the arm unit through the fixed holding bolt (3) and is locked to the outside end of a sub-arm of the arm unit through the movable holding bolt (5). It is thus easy to detachably mount the attachment to the outside end of the arm unit. The device also allows an attachment to be mounted to the arm unit as if no links were used at the junction between the attachment and the arm unit. Therefore, the device does not lengthen the originally designed distance from the outside end of the arm unit to the lower end of the attachment irrespective of use of the link unit. The device is thus free from reducing the excavation power of an excavator and almost completely prevents any attachment from colliding with the excavator body, and prevents the excavator from overturning, incurring safety hazards while working.

Description

DEVICE FOR HOLDING ATTACHMENTS IN POWER EXCAVATORS

Technical Field

The present invention relates, in general, to a device for detachably holding an attachment to the outside end of an arm unit in power excavators and, more particularly, to an attachment holding device free from lengthening an originally designed distance from the outside end of the arm unit to the lower end of an attachment irrespective of use of a link unit as an attachment holding means, thus being free from undesirably reducing the excavation power of an excavator.

Background Art

As well known to those skilled in the art, a variety of attachments for power excavators, such as buckets and breakers, are selectively and removably attached to the outside end of an arm unit as desired. Of such conventional attachments for power excavators, buckets are most widely used as they may be preferably used in several applications. In order to allow an easy change of such attachments relative to the arm unit of an excavator, a hydraulically actuated link unit is most preferably and widely used as an attachment holding device in the prior art. In the case of an excavator designed to hold an attachment at the outside end of an arm unit using a separate connection bolt, it is necessary for two or more people to strike the connection bolt with heavy hammers while changing an existing attachment with another attachment. In such a case, an operator, positioned within a control cab, has to control the moving parts of the excavator so as to allow the connection bolt to be easily removed from or inserted into a designated bolt hole, and to accomplish an easy change of the attachments. Therefore, this structure exceedingly consumes labor and time while changing the attachments, and sometimes incurs safety hazards during an attachment changing operation.

In an effort to solve the problems, a link unit, or an attachment holding device for allowing an easy change of attachments in power excavators, has been proposed and preferably used. The link unit is set in the outside end of an arm unit and is designed to allow an existing attachment to be easily changed with another one when necessary. An example of conventional link units, used as an attachment holding device for power excavators, may be referred to Korean U.M. Publication No. 95-5247, applied by the inventor of this invention. This link unit is designed to be mounted to the outside end of an arm unit at its upper end using a holding bolt. A desired attachment is removably mounted to the lower end of the link unit. However, this link unit is problematic in that it undesirably increases the distance between the outside end of the arm unit to the lower end of an attachment by the length of the link unit. This lengthened distance finally reduces the excavation power of the excavator.

That is, the above link unit is mounted to the outside end of an arm unit at its upper end using a holding bolt. In order to bring an attachment into engagement with the arm unit using the link unit, the connection bolt of the attachment is inserted into a bolt opening formed on the lower end of the link unit. Therefore, the distance between the outside end of the arm unit to the lower end of the attachment is undesirably lengthened by the distance between the holding bolt to the connection bolt. The excavation power of the excavator is reduced in inverse proportion to the lengthened distance. This finally reduces working efficiency during an excavating work of the excavator.

On the other hand, conventional power excavators are typically designed to optimally perform their operational functions with an attachment being completely mounted to the outside end of an arm unit. Therefore, when the distance between the outside end of the arm unit to the lower end of the attachment is undesirably lengthened as described above, the attachment may collide with the body of the excavator while working. Furthermore, the gravity center of the excavator is moved forward by said lengthened distance, thus making the excavator unstable. The excavator may overturn due to the unstable gravity center while working.

Disclosure of the Invention

Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide a device for detachably holding an attachment to the outside end of an arm unit in power excavators, which is free from lengthening an originally designed distance from the outside end of the arm unit to the lower end of the attachment irrespective of use of a link unit as an attachment holding means, and which is thus free from reducing the excavation power of an excavator.

Another object of the present invention is to provide a device for detachably holding attachments in power excavators, which is designed to almost completely prevent an attachment from colliding with the body of an excavator and to prevent the excavator from overturning, incurring safety hazards while working.

In order to accomplish the above objects, the present invention provides a device for detachably holding an attachment to an arm unit of an excavator, comprising: a link frame provided with sub-arm connection means at an upper part of its central portion for being held on an outside end of a sub-arm of the arm unit; a fixed holding bolt provided at a first end portion of the link frame for being used as a rotating shaft of the attachment while coupling the attachment to an outside end of a main arm of the arm unit; a hydraulic cylinder actuator set in the link frame while being fixed to the link frame by a fixing pin; and a movable holding bolt provided at a second end portion of the link frame and coupled to an outside end of a piston rod of the cylinder actuator, thus being movable by the actuator, the movable holding bolt being used for holding the attachment in cooperation with the fixed holding bolt and applying a hydraulic force from the sub-arm to the attachment.

Brief Description of the Drawings

The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

Fig. 1 is a perspective view of an attachment holding device in accordance with the primary embodiment of the present invention, with the device and a conventional bucket being separated from each other;

Fig. 2 is a partially sectioned view, showing the construction of the attachment holding device of Fig. 1; Fig. 3 is a partially broken plan view of a link unit included in the device of Fig. 1;

Figs. 4a and 4b are side views, showing an operational effect of the device of Fig. 1, in which:

Fig. 4a shows a bucket before it is locked to the link unit of the device; and Fig. 4b shows the bucket completely locked to the link unit;

Fig. 5 is a perspective view of an attachment holding device in accordance with the second embodiment of the present invention, with the device and a conventional bucket being separated from each other;

Fig. 6 is a partially sectioned view, showing the construction of the attachment holding device of Fig. 5;

Fig. 7 is a partially broken plan view of a link unit included in the device of Fig. 5; and Figs. 8a and 8b are side views, showing an operational effect of the device of Fig. 5, in which:

Fig. 8a shows a bucket before it is locked to the link unit of the device; and

Fig. 8b shows the bucket completely locked to the link unit. Best Mode for Carrying Out the Invention

Figs. 1 to 4b show the construction and operation of an attachment holding device in accordance with the primary embodiment of this invention. As shown in the drawings, the attachment holding device of this invention comprises two first bolt hooks 13 and two second bolt hooks 14, which are formed on the upper end portion of an attachment 12 at front and rear parts of said upper end portion. In the preferred embodiments, the attachment 12 is referred to as a conventional bucket for ease of description. However, it should be understood that another attachment, such as a breaker, may be used with the holding device of this invention without affecting the functioning of the invention. The device also comprises a link unit 1. The link unit 1 consists of a link frame 2, which has a fixed holding bolt 3 at its first end portion. The link unit 1 thus commonly engages with both the first bolt hooks 13 of the bucket 12 and the outside end of a main arm 15 at the fixed holding bolt 3. The above link unit 1 also has two sub-arm connection bosses 4 at the upper part of its central portion, and so the unit 1 is assembled with the outside end of a sub-arm 16 of the arm unit at the bosses 4 using a separate holding bolt 17. Two hydraulic cylinder actuators 7 are set in the link frame 2. The two cylinder actuators 7 are commonly fixed to the link frame 2 by a fixing pin 9. A movable holding bolt 5 is coupled to the outside ends of the piston rods 8 of said two cylinder actuators 7, thus being operable in conjunction with the two actuators 7. In the primary embodiment, the movable holding bolt 5 is perpendicularly coupled to the two piston rods 8. A bolt guide means 6, or a guide hole, is formed on the link frame 2 and guides a hydraulically actuated reciprocating action of the movable holding bolt 5. In addition, a draft hook 11 is formed on the second end portion of the link frame 2. When the link unit 1 is free from any attachment, the unit 1 may be used as a drafting means with the draft hook 11. In the above link unit 1, each of the fixed and movable holding bolts 3 and 5 projects from both sides of the link frame 2 outwardly at both ends thereof. Therefore, the two holding bolts 3 and 5 of the link unit 1 are easily and stably caught by the two sets of bolt hooks 13 and 14 of the bucket 12, respectively.

In the drawings, the reference numeral 10 denotes a directional control solenoid valve for the two cylinder actuators 7. In order to attach the link unit 1 to the outside end of an arm unit of an excavator, the link unit 1 is mounted to the outside end of the sub-arm 16 at the two sub-arm connection bosses 4 using the separate holding bolt 17 fitted into the bosses 4. The link unit 1 is also mounted to the outside end of the main arm 15 at the fixed holding bolt 3.

After the link unit 1 is held on the outside ends of the two arms 15 and 16, an attachment, or a conventional bucket 12, is attached to the link unit 1. In order to attach the bucket 12 to the link unit 1, an operator has to control the hydraulic circuit system of the excavator, thus appropriately moving the main and sub arms 15 and 16 of the arm unit so as to lock the fixed holding bolt 3 of the unit 1 into the first bolt hooks 13 of the bucket 12 as shown in Fig. 4a. Thereafter, the arm unit is gradually and appropriately moved inwardly toward the excavator body, and so the bucket 12 is rotated clockwise around the fixed holding bolt 3 in the drawings. The back of the bucket 12 is thus raised up until the back of the bucket 12 is brought into contact with the second end portion of the link unit 1 as shown in Fig. 4b. In such a case, the movable holding bolt 5 of the link unit 1 is positioned in front of the second bolt hooks 14 of the bucket 12. The hydraulic cylinder actuators 7 are operated under control of the directional control valve 10 so as to extend the piston rods 8 forwardly. The movable holding bolt 5 is thus moved forwards under the guide of the opening 6 of the link frame 2, and so the bolt 5 is finally fitted into the second bolt hooks 14 of the bucket 12. Therefore, the bucket 12 is completely held on the outside end of the arm unit by the link unit 1.

On the other hand, in order to detach the bucket 12 from the link unit 1, the two cylinder actuators 7 are operated under the control of the valve 10 so as to retract the piston rods 8 into the cylinders of the actuators 7. The movable holding bolt 5 is thus moved backwards under the guide of the opening 6 of the link frame 2, and so the bolt 5 is removed from the second bolt hooks 14 of the bucket 12. Thereafter, the arm unit is operated by controlling the hydraulic circuit system of the excavator, thus appropriately moving the main and sub arms 15 and 16 of the arm unit so as to remove the fixed holding bolt 3 of the unit 1 from the first bolt hooks 13 of the bucket 12. Therefore, the bucket 12 is removed from the link unit 1.

When the link unit 1 is free from any attachment 12, the unit 1 may be used as a drafting means with the draft hook 11. That is, since the link frame 2 of this invention is provided with the draft hook 11 at its second end portion, the link unit 1 may be preferably used as a drafting means in place of a conventional draft hook fixedly mounted on the back of a bucket having a weight not less than 1 ton. Due to the draft hook 11, it is possible to improve work efficiency during a drafting operation.

Figs. 5 to 8b show the construction and operation of an attachment holding device in accordance with the second embodiment of this invention. As shown in the drawings, the attachment holding device of this embodiment comprises two bolt hooks 13 and a support plate 18, which are formed on the upper end portion of an attachment 12, or a bucket, at front and rear parts of said upper end portion. Two bolt receiving holes 19 are formed on the support plate 18 while spacing out at an interval.

The device also comprises a link unit 1. The link unit 1 consists of a link frame 2, which has a fixed holding bolt 3 at its first end portion. The link unit 1 thus commonly engages with both the two bolt hooks 13 of the bucket 12 and the outside end of a main arm 15 at the fixed holding bolt 3. The above link unit 1 also has two sub-arm connection bosses 4 at the upper part of its central portion, and so the unit 1 is assembled with the outside end of a sub-arm 16 of the arm unit at the bosses 4 using a separate holding bolt 17. In addition, two hydraulic cylinder actuators 7 are set in the link frame 2. The two cylinder actuators 7 are commonly fixed to the link frame 2 by a fixing pin 9. The link unit 1 also has a draft hook 11 on the second end portion of the link frame 2 in the same manner as that described for the primary embodiment.

Two movable holding bolts 5' are coupled to the outside ends of the piston rods 8 of said two cylinder actuators 7, respectively, thus being operable in conjunction with the two actuators 7. In the second embodiment, the movable holding bolts 5' are axially coupled to the two piston rods 8. A bolt guide means 20, consisting of two axial guide holes, is formed on the link frame 2 and guides a hydraulically actuated reciprocating action of the movable holding bolts 5'.

In the above link unit 1, the fixed holding bolt 3 projects from both sides of the link frame 2 outwardly at both ends thereof. Therefore, the fixed holding bolt 3 of the link unit 1 is easily and stably caught by the two bolt hooks 13 of the bucket 12, respectively. On the other hand, the bolt receiving holes 19 of the support plate 18 are individually tapered at their inside end portion, thus allowing the attachment 12 to be firmly locked to the link unit 1. In order to attach the link unit 1 to the outside end of an arm unit of an excavator, the link unit 1 is mounted to the outside end of the sub-arm 16 at the two sub-arm connection bosses 4 using the separate holding bolt 17 fitted into the bosses 4. The link unit 1 is also mounted to the outside end of the main arm 15 at the fixed holding bolt 3.

After the link unit 1 is held on the outside ends of the two arms 15 and 16, an attachment, or a conventional bucket 12, is attached to the link unit 1. In order to attach the bucket 12 to the link unit 1, an operator has to control the hydraulic circuit system of the excavator, thus appropriately moving the main and sub arms 15 and 16 of the arm unit so as to lock the fixed holding bolt 3 of the unit 1 into the bolt hooks 13 of the bucket 12 as shown in Fig. 8a. Thereafter, the arm unit is gradually and appropriately moved inwardly toward the excavator body, and so the bucket 12 is rotated clockwise around the fixed holding bolt 3 in the drawings. The back of the bucket 12 is thus raised up until the back of the bucket 12 is brought into contact with the second end portion of the link unit 1 as shown in Fig. 8b. In such a case, the two movable holding bolts 5' of the link unit 1 are positioned in front of the bolt receiving holes 19 of the bucket 12. The hydraulic cylinder actuators 7 are operated under control of the directional control valve 10 so as to extend the piston rods 8 forwardly. The movable holding bolts 5¹ are thus moved forwards under the guide of the holes 19 of the link frame 2, and so the bolts 5' are finally fitted into the bolt receiving holes 19 of the bucket 12. Therefore, the bucket 12 is completely held on the outside end of the arm unit by the link unit 1.

On the other hand, in order to detach the bucket 12 from the link unit 1, the two cylinder actuators 7 are operated under the control of the valve 10 so as to retract the piston rods 8 into the cylinders of the actuators 7. The movable holding bolts 5' are thus moved backwards, and so the bolts 5' are removed from the holes 19 of the bucket 12. Thereafter, the arm unit is operated by controlling the hydraulic circuit system of the excavator, thus appropriately moving the main and sub arms 15 and 16 of the arm unit so as to remove the fixed holding bolt 3 of the unit 1 from the bolt hooks 13 of the bucket 12. Therefore, the bucket 12 is removed from the link unit 1.

Industrial Applicability

As described above, the present invention provides a device for detachably holding an attachment, such as a bucket or a breaker, to the outside end of an arm unit in power excavators. In the device according to the primary embodiment, two sets of bolt hooks are provided on an attachment. The device also has a link unit, comprising fixed and movable holding bolts set in a link frame. The movable bolt is operated by a hydraulic cylinder actuator. The attachment is mounted to the outside end of a main arm of the arm unit through the fixed holding bolt and is locked to the outside end of a sub-arm of the arm unit through the movable holding bolt. It is thus easy to detachably mount the attachment to the outside end of the arm unit. In the primary embodiment, the movable bolt is perpendicularly coupled to the piston rod of the cylinder actuator. In the second embodiment, the movable bolt is axially coupled to the piston rod of the cylinder actuator. Therefore, in the device of the second embodiment, a support plate, having a bolt receiving means, is provided on the attachment in place of the second bolt hooks. The attachment holding device also allows an attachment to be mounted to the arm unit as if no links were used at the junction between the attachment and the arm unit. Therefore, the device does not lengthen the originally designed distance from the outside end of the arm unit to the lower end of the attachment irrespective of the use of the link unit.

The attachment holding device of this invention is thus free from reducing the excavation power of the excavator. In addition, the device almost completely prevents any attachment from colliding with the excavator body and prevents the excavator from overturning, incurring safety hazards while working.

Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

Claims

Claims :

1. A device for detachably holding an attachment to an arm unit of an excavator, comprising: a link frame provided with sub-arm connection means at an upper part of its central portion for being held on an outside end of a sub-arm of the arm unit; a fixed holding bolt provided at a first end portion of said link frame for being used as a rotating shaft of said attachment while coupling the attachment to an outside end of a main arm of said arm unit; a hydraulic cylinder actuator set in said link frame while being fixed to the link frame by a fixing pin; and a movable holding bolt provided at a second end portion of the link frame and coupled to an outside end of a piston rod of said cylinder actuator, thus being movable by the actuator, said movable holding bolt being used for holding said attachment in cooperation with the fixed holding bolt and applying a hydraulic force from the sub-arm to said attachment.

2. The device according to claim 1, wherein said movable holding bolt is perpendicularly coupled to the piston rod of said actuator, with bolt guide means being formed on said link frame and being used for guiding a hydraulically actuated reciprocating action of said movable holding bolt.

3. The device according to claim 1, wherein said movable holding bolt is axially coupled to the piston rod of said actuator, with bolt guide means being formed on said link frame and being used for guiding a hydraulically actuated reciprocating action of said movable holding bolt.

4. The device according to claim 1, further comprising a first bolt hook and a second bolt hook formed on an upper end portion of said attachment at positions corresponding to said fixed and movable holding bolts of the link frame, thus respectively engaging with said fixed and movable holding bolts.

5. The device according to claim 1, further comprising a bolt hook and a support plate formed on an upper end portion of said attachment at positions corresponding to said fixed and movable holding bolts of the link frame, with bolt receiving means being formed on said support plate, said bolt hook and said support plate thus respectively engaging with said fixed and movable holding bolts.

6. The device according to claim 1, wherein a draft hook is formed on the second end portion of said link frame .