CA1073685A

CA1073685A - Dredger chain joint

Info

Publication number: CA1073685A
Application number: CA282,289A
Authority: CA
Inventors: Izaak Zabel
Original assignee: BOS KALIS WESTMINSTER GROUP NV
Current assignee: BOS KALIS WESTMINSTER GROUP NV
Priority date: 1976-07-16
Filing date: 1977-07-07
Publication date: 1980-03-18
Also published as: JPS5311260A; FR2358516A1; SE433511B; PT66767B; PT66767A; NL172581B; GB1585795A; DE2729804B2; DE2729804A1; BE856713A; ES460728A1; NL172581C; SE7708030L; IT1080636B; NL7607909A

Abstract

Abstract of the Disclosure A bearing construction is provided such as for a dredger chain, wherein two bearings are disposed co-extensively. Each bearing comprises an outer bearing bushing received in a lug and:
having an internal concave bearing face. An inner bearing bushing having a corresponding convex outer surface is mounted within the outer bearing bushing and a pivot pin is accommodated in said inner bearing bushing, while on either side of said lug a link is disposed on the pivot pin. The construction reduces wear and noise during operation.

Description

3 rj A D~EDGER CHAIN JOINT
The present invention relates to a joint for a chain such as used for example in a dredger, wherein successive links and/or buckets are pivotally inter-connected.
In general, the successive buckets of a bucket dredger are interconnected through links. The buckets with links run over a polygonal bottom tumhler and a polygonal top tumbler, the top tumbler serving for the drive, and the bottom tumbler being disposed at the bottom of a bucket ladder. The dredging operations are controlled by means of the dredging ladder. The top and bottom tumblers are mounted on parallelly extending shafts, the pivot pins of the link bearings being parallel to these shafts. Mostly, each bucket is connected through two pairs of links to the preceding bucket and likewise by means of two pairs of links to the next bucket, the pivot pins at one side of the bucket always being co-extensive. Such a construction is described inter alia in Dutch patent application 75,05387 of O. & K. Orrenstein & Koppel AG published 12th November 1975. In i~ use i5 made of cylindrical bearing faces in the shape of a bearing bushing of bearing material that is disposed more or less fixedly in a bore in a lug of a bucket, the bearing bushing being adapted for sliding movement relative to a pivot pin. A link is mounted on the pivot pin on opposite ends thereof. These links are connected to a next bucket.
In view of the substantial wear occurring in practice, and the noise during operation going therewith, it is proposed in said prior Dutch application to provide the bearing on either side with a resilient diaphragm which is vulcanized both to an inner ring and to an outer ring in order to prevent leakage of lubricating ~' . .

36~5 oil. The inner ring is secured to the pivot pin and the outer ring is fixed in a bore in the lug. The pivoting movements between the lug and the links as they pass the top and bottom tumblers has to be taken up ~y de~ormation of the resilient diaphragm. It is the object of the present invention to provide an improved dredger chain joint construction of the above described type.
~ In accordance with the present invention there is - provided a bearing construction for a dredger chain, wherein two `~
1~ bearings are disposed co-axially and wherein each bearing comprises an outer bearing bushing disposed in a lug, while on eithe~ side of the lug there is mounted a link on a pivot pin, upon which is ; mounted an inner bearing bushing having a convex outer surface, the outer bearing bushing being mounted in a bore in the lug and being provided with a corresponding internal concave bearing face.
Although, theoretically, cylindrical bearings will be sufficient for a bucket dredger chain, it has surprisingly been ; found in practice that the use of a spherical joint construction results in a substantial reduction of the wear and hence an increase in the lifetime and a reduction of the noise during operation. Such a bearing may be provided in known manner with lubrication, and use may be made of bearing sealings, such as sleeves, cupped washers, diaphragms, strings and other resilient packing constructions.
It has furthermore been found that it is effective to mount the convex bearing bushing on the pivot pin with a clearance of about lmm. In spite of this clearance, it has turned out in practice that the relative movements occur sub-

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stantially between the convex and the concave bearing bushings, while the relativ~ly large clearances facilitate assembly and disassembly of the bearing. ~or the bearing sealing, use may ~e made of a double lip packingl V-shaped in cross-section, which is mounted on a mounting sleeve or a ~earing ring and is contiguous with a separate retaining sleeve in the lug, against which the concave outer ring is mounted. For the supply of lubrication~ said lug may accommodate an oil reservoir which is designed preferably eccentric.
Further features of the in~ention will be apparent from the following description o~ an embodiment according to the present invention, given by way o example, with reference to the accompanying drawing.
The single figure shows partly in cross section a bearing construction according to the present invention.
A relatively heavy lug l is connected to a dredger bucket, not shown, by a connecting portion diagrammatically indicated by 2; this may be for instance a supporting rib of a bucket. Lug 1 accommodates a bearing comprising a cylindrical pivot pin 3 having a head 4 and a cotter hole 5. On either side of lug 1 there is present a link 6, 7, which links may be connected either to a lug on a next dredger bucket or may be integral with a next dredger bucket. On the pivot pin there are disposed two stepped mounting sleeves 8, on the outer surfaces o~ which there is disposed a double lip packing or cupped washer 9, V-shaped in cross-section. It will be noted that with this construction at least two lips are present between the exterior and the bearing interior, so that any difference in pressure is equalised in a corresponding number of

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~36~5 steps. Between the collars of sleeves 8 there is disposed an inner bearing bushing 10, the outer ~ace of which is convex or spherical. Said convex inner bearing bushing 10 is accommodated in two outer ~earing bushing portions 11, each having a corresponding concave internal ~earing face r whîch portions, after being applied r are indussoluble interconnected to ~orm an outer bearing bushing.
Retaining sleeves or rings 12 bear against the outsides of said outer bearing bushing. ~he inner face of each ring 12 functions as a sealing face of the respective cupped washer 9: the rings may be secured w;th a specific pre-tension in the lug 1 or be fixed in a different manner. O-rings 13 are disposed in grooves of sleeves 8, on the one hand to prevent leakage of lubricant present in the bearing r and on the other hand to prevent water and/or dirt from penetrating into the bearing. Sleeves 8 are mounted with a relatively large clearance o~ about 1% of the pin diameterr in this embodiment about lmm on pin 3 r the links being mounted with a oorresponding clearance. Furthermorer there is shown a lubricant reservoir 14 formed by a central circumferential groove in lug 1. Said groove is eccentrically disposed such that at the location where the greatest forces are exertedr the least quantity of material has been removed~ Finally the bearing is retained by a retaining ring 15 on pin 3 r which may be secured by means of a cotter r not shown r in cotter opening 5.
It is observed that on each side of a bucket there are disposed at least two of such co-extensive bearings. By removing the cotter r the links can be easily removed from the pin 3, while the pin itself can be withdrawn from the sleeves 8.

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~fter this, the bearing can he entirel~ removed from the bore of lug 1. The large and heavy parts, such as lug 1 and links 6 and 7, are provided with simple cylindrical bores, and the pin, too, has a simple cylindrical shape. Only the lighter bearing, mounting 5 and retaining sleeves are of convex or concave, or of stepped, configuration. If desired, the entire ~earing may be mounted in the lug of the bucket in the workshop, while the bearing pins 3 and possibly the links need only ~e mounted during the assembly on a dredger.

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Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A hearing construction for a dredger chain, wherein two bearings are disposed co-axially and wherein each bearing comprises an outer bearing bushing disposed in a lug, while on either side of the lug there is mounted a link on a pivot pin, upon which is mounted an inner bearing bushing having a convex outer surface, the outer bearing bushing being mounted in a bore in the lug and being provided with a corresponding internal concave bearing face.

2. A bearing construction according to claim 1, wherein the inner bearing bushing is disposed on the pivot pin with relatively large clearance as defined herein.

3. A bearing construction according to claim 1, wherein the inner bearing bushing is mounted on the pivot pin by means of mount-ing sleeves which are of stepped configuration to provide respective collars, the inner bearing bushing being retained between the said collars on the mounting sleeves, the sleeves having internally a relative large clearance as defined herein relative to the pivot pin.

4. A bearing construction according to claim 3, wherein on each stepped mounting sleeve, on the portion having the largest diameter thereof, there is provided a flexible packing disposed to be adjacent the inner bearing bushing.

5. A bearing construction according to claim 4, wherein there is mounted in the bore in the lug, on either side of the outer bearing bushing, a respective retaining sleeve retaining the outer bearing bushing in the lug bore, an inner face of each sleeve functioning as a sealing face abutting the respective outer bearing bushing portion.

6. A bearing construction according to any one of claims 1 to 3, wherein the outer bearing bushing has a divided configuration constituted by two separate bushing portion parts which are interconnected.

7. A bearing construction according to any one of claims 1 to 3, wherein a lubricant groove is provided around the outer bearing bushing constituted by an eccentric recess centrally disposed in the lug.

8. A bearing construction according to claim 4 or 5, wherein the outer bearing bushing has a divided configuration constituted by two separate bushing portion parts which are interconnected.

9. A bearing construction according to claim 4 or 5, wherein a lubricant groove is provided around the outer bearing bushing constituted by an eccentric recess centrally disposed in the lug.