WO1984001085A1

WO1984001085A1 - Attachment device

Info

Publication number: WO1984001085A1
Application number: PCT/SE1982/000297
Authority: WO
Inventors: Stig Pettersson
Original assignee: Stig Pettersson
Priority date: 1982-09-24
Filing date: 1982-09-24
Publication date: 1984-03-29
Also published as: FI842090A; FI76475B; FI76475C; FI842090A0

Abstract

An attachment device for chains (11) at shrub clearing units comprises a head (1), centre (1), preferably in the form of a circular plate rotatable in the plane of the device, to which head the chains (11) are intended to be attached, and from which the chains are intended to be swung outward substantially in said plane. The device is characterized in that said centre (1) comprises preferably equal grooves (3) located in said plane, that each groove (3) opens in two places (5, 6) at the periphery (4) of said centre and extends in an arc (7), which preferably is a part of a circular arc (7), between said places (5, 6), and in each groove (3) an attachment ring (8) for a chain (11) is located and partially projects outside the periphery (4) of said centre (1), and the grooves (3) at least partially are covered by a cover (9) or the like.

Description

Attachment device

This invention relates to an attachment device at brush clearing units, by means of and on which clearing chains are mounted on a rotary head, centre.

At a conventional embodiment of a so-called brush clear¬ er a head or centre, in the form of a substantially plane circular disc rotatable in a horizontal plane, is located at a hydraulically operated axle, and normally three chains are attached to the head with 120 divis¬ ion along the periphery, which chains in operation are intended to swing outward in a horizontal plane.

At known devices, the attachment of the chains to said head has proved to involve great problems. At one known device the chains are threaded on a wire, which at each end is provided with a hook or the like. In one plane circular surface of the head grooves are provided which form a regular triangle with corners at the periphery of the head. In the grooves said wire is intended to be positioned so that an eye, to which a chain is att- ached, is formed at*each corner, in such a manner, that the wire is retained in place in the grooves by two fixing pins located in one of the grooves and intended to co-operate with said hooks, and by a cover covering the grooves. At such a device said hooks and/or said eyes break, often after a very short time of operation, whereby one or several chains get loose. The substantial dynamic strains arising in operation concentrate at the design described to these members. The eyes are subjected a.o. to a great number of bendings, due to forces arising in the circumferential direction of the head and prop¬ agating from the chain to the eye.

A chain thus disconnected can fly up to 300 m and there-

OMPI μ. wipo . by greatly endangers both the operator and the public, because clearing work often is carried out in the vicinity of or along roads.

The present invention relates to an attachment head or chain attachment, by which the aforesaid problems are entirely eliminated.

The invention, thus, relates to an attachment device for chains at shrub clearing units, comprising a head, centre, preferably in the form of a circular plate rotatable in the plane of the device, to which plate the chains, normally three in number, are intended to be attached, and from which the chains are intended to swing outward substantially in said plane.

The attachment device is characterized in that said centre comprises three equal grooves, which are located in said plane and uniformly distributed in respect of the circumference of said centre, that each groove opens in two places at the periphery of said centre and extends in a curve, which preferably is part of a circular arc, between said places, and in each groove an attachment ring for a chain is located and partially projects outside the periphery of said centre, and the grooves at least partially are covered by a cover or the like.

The invention is described in greater detail in the following, with reference to the accompanying drawing, in which Fig. 1 shows an attachment head, centre, acc¬ ording to the invention, seen from the side where the chains with attachment rings are inserted into the head, and where one chain is shown, and the cover is not shown, and Fig. 2 is a section A-A according to Fig. 1. -.

In Fig. 1 the numeral 1 designates an- attachment head or centre comprised in the device preferably in the form of a circular plate 1, which is rotatable in its plane by means of, for example, a central hole 2, into which an axle (not shown) ^"is intended to. be inserted perpendicularly to said plane.

When three chains are to be attached, said centre 1 5 comprises three equal grooves 3₃ which are located subst¬ antially in said plane and uniformly distributed in respect of the ci rcumference k , periphery k , of said centre, i.e. with 120° division. Each groove 3 opens in two places 5,6 at the periphery and extends in an arc 7_} which 0 preferably is a part of a circular arc 7, between said places 5,6.

In each groove 3 an attachment ring 8 is provided, which projects partially outside the periphery -4. In Fig. 1 only one attachment ring 8 is shown. The att- 5 achment rings 8 are intended to be retained in place in the grooves by means of a cover 9 or the like, for example in the form of a circular disc 9 located in a recess 10 and intended to be fixed by through bolts (not shown). The cover 9 is not shown in Fig. 1 and 0 is indicated by dashed line in Fig. 2.

A chain 11 can be attached directly to the attachment ring 8, but according to a preferred embodiment acoupl¬ ing ring 12 is provided to connect the ring 8 and chain 11 and to extend through the ring 8 and one link 5 13 of the chain 11.

According to a preferred embodiment, the grooves 3 and rings 8,12 have substantially square cross-section, as shown in Fig. 1.

The mode of operation of a device according to the in- Q vention should be apparent in view of the above descript¬ ion.

A device according to the invention takes up a.o. dyn-r amic strains and forces without detrimental bending

-BU EA

OMPI moments being transferred to the attachment. Experim¬ ents with an operational prototype prove that the serv¬ ice life of an attachment device according to the in¬ vention is many times greater than that at known dev- ices. The service life is also more than ten times long¬ er than that of the chains under normal operation cond¬ itions. The manufacturing costs are substantially the same as of known devices.

Some embodiments of a device according to the inventi- on have been described above. It is, of course, possible to imagine more embodiments and minor alterations with¬ out therefore abandoning the invention idea.

The said centre, for example, can consist of two subst¬ antially_,equal halves, which for example are assembled by bolts, and between which said grooves 3 are formed. In this case each half constitutes a "cover".

According to a further embodiment, which in certain cases is preferable, six grooves 3 are intended for six chains. Three grooves are located in connection to one side of said centre, substantially as in Fig. 1, and three grooves are located in a corresponding way in connection to the other side of said centre. The grooves are arranged so that the chains are distributed substantially uniformly about the circumference ^'of said centre.

According to a variant of this embodiment, the grooves 3, chains, are arranged in groups, each group compris¬ ing two adjacent grooves, one on the upper side and one on the lower side. The division between the grooves in each group is smaller than 60°, for example 50-55°, and the division between the- groups in a corresponding way is greater than 60°, for example 70-65°.

The invention, thus, must not be regarded restricted to the embodiments set forth above, but can be varied with- in the scope of the attached claims.

Claims

1. An attachment device for chains at shrub clearing units, comprising a head, centre, preferably in the form of a circular plate, rotatable in the plane of the dev- ice, to which head- the chains are intended to be att¬ ached, and from which they are intended to be swung outward substantially in said plane, c h a r a c t e r - i z e d i n that said centre (1) comprises prefer¬ ably equal grooves (3) located in said plane, that each groove (3) opens in two places (5,6) at the periphery (4) of said centre and extends in an arc ; (7), which preferably is a part of a circular arc (7), between said places (5,6), and in each groove (3) an attachment ring

(8) for a chain (11) is located and partially projects outside the periphery (4) of said centre (1), and the grooves (3) at least partially are covered by a cover

(9) or the like.

2. A-:device as definsd in claim 1, c h a a c t e r ¬ i z e d i n that a chain (11) is intended to be conn- ected to said attachment ring (8) by means of a coupling ring (12) extending through the attachment ring (8) and a chain link (13).

3. A device as defined in claim 2, c h a r a c t e r ¬ i z e d i n that said grooves {^■* ) and said rings (8,12) have substantially square cross-section.

4. A device as defined in any one of the preceding claims, c h a r a c t e r i z e d i n that three grooves (3) are located in connection to one side of said centre (1) and three grooves (3) are located in connection to the other side thereof.

5. A device as defined in claim 4, c h a r a c t e r ¬ i z e i n that the grooves (3) are arranged in groups, each group comprising two adjacent grooves, one on the upper side and one on the lower side, and the division between the grooves in each group is smaller than 60 , for example 50-55° , and the division between the groups in a corresponding way is greater than 60°, for example 70-65°.