GB2064450A - Connection Link for Endless Track Chain - Google Patents

Abstract

A connection link for an endless track chain comprises two half-links (11, 12) that are interconnected along a junction line (13); the junction line passing between two offset side segments (18, 19) respectively of the half-links placed in parallel planes, and extending diagonally with respect to the link axis; and a coupling member (22) housed in a seat formed by recesses in the half-links and located at the central portion of said junction line just upon the longitudinal axis of the link. <IMAGE>

Description

SPECIFICATION Connection Link for Chains The present invention relates to a connection device for chains, track chains for tracked vehicles of the tractor type, and to other similar linked devices.

The connection device of the present invention is considered to be particularly useful in continuous linked track chains used in tracked vehicles of the tractor type, and for convenience will be described with reference thereto although it will be understood that the present invention is not limited to such use.

A track chain of tractor type essentially comprises a plurality of shoes (or soles) attached by means of bolts to links (of a track chain) which are pivotally connected to each other by means of pins and bushings.

A connection pin or a connection link are conventionally provided in each track chain. Such member, which is firmly fixed in its position in operative conditions, thereby enables the links of the track chain to be detached from the vehicle.

In general (for removing the track chain, particularly when this action is taken on the field) a connection link consisting of a plurality of parts is used which can be more easily and conveniently employed than a connection pin, particularly in large sized vehicles.

This resulted in the adoption of connection links consisting of two or three parts interconnected to each other by means of set screws, by which in turn also the respective shoes are fixedly held, and which are joined along multiple junction profiles extending along a more or less long portion of the junction line of said parts, or by means of connection pins force fitted into the parts, parallel to the direction of the set screws.

It is an object of this invention to avoid some draw-backs of the systems as used up till now, such as the difficulty of obtaining a uniform distribution of the stresses due to the tension exerted by the track chain upon the various sectors of a multiple coupling profile; the high structural precision thereby required; the transfer of a not negligible percentage of the track chain tension to the connection screws which are noticeably pre-stressed or the necessity of high precision mechanical couplings for the connection by means of focce fitted pins; to a certain extent, a lack of stiffness in the longitudinal plane of the link and generally a lack of feasibility of use and a limited capability to withstand multiple opening and closing manoeuvres for the track chain, due to wear in the pin seats.

It is a further object of the invention to eliminate the necessity to use a special shoe in correspondence with the connection link of the track chain.

According to the invention, a device is provided consisting of two link parts (or half-links) each having in an end portion a seat for force fitting of the pin and of the bushing, respectively, and a function surface between the two parts, as well as a seat for the coupling member. The cross section of the junction surface is a line which delineates two side rectilinear portions, which extend diagonally with respect to the pin-bushing axis of the link and are intended as bearing lines of a half-link upon the other, as well as a central portion that is intended as a mutual bearing line forming a shaped portion which in operative condition is pre-stressed by said set screws.

More particularly the invention provides a connection link which consists of two twin halflinks coupled along a junction line including two offset side segments laying in parallel planes and diagonally extending with respect to the link axis and of a coupling member designed to operate as a connection part, adapted to withstand tension stresses, housed in a seat located at the central portion of said junction line.

Said coupling member may be a shaped metal key provided with an insertion bevel and engaged by force fitting into a seat formed by recesses in the half-links respectively.

The two twin half-links may be securely fastened by means of two parallel set screws, that are passed through holes provided in the one of the links element and are tightened within blind threaded holes provided in the other of the links.

It is a preferred feature of this invention to provide a connection link wherein the distance between said set screws is the same as the distance between the screws of other links of the track, so as to enable a standard shoe to be mounted thereon.

The mixtilinear junction profile of the two halflinks preferably extends parallel to the junction axes of the link and ends near a rolling and a shoe attachment planar surfaces respectively of the two links along a direction substantially perpendicular to said surfaces.

The two half-links may have a substantial increase in their cross sectional thickness, just outside of the linkage areas of the pin and of the bushing.

The lay-out of the sectional planes along the junction line in a first order approximation is parallel to the pin and bushing.

The invention will be described with reference to the accompanying drawings in which a preferred embodiment of the invention is shown as an example and not by way of limitation, and in which: Figure 1 is an elevation view of a complete connection link (right), consisting of three parts, attached to a shoe by means of suitable screws; Figure 2 is a plan view of a (right) half-link at the bushing side (as it can be seen from the shoe); Figure 3 is a plan view of the connection key; and Figure 4 is a plan view of said half-link at the pin side (as it can be seen from the junction line).

Referring now to Figure 1, the connection link of this invention consists of two half-links 11 and 1 2 which are overlapped with each other, matched and joined by means of a force fitted key 22 along the junction surface shown as line 13, the key being formed with a bevel to facilitate its entry into the seat provided by recesses formed in the half-links respectively.

Two set screws (long stem screws) 14 connect, by means of two through holes 20, a shoe 1 5 and the bushing side half-link 12 to the pin side half-link 11, two blind threaded holes being provided aligned with the previously mentioned ones to receive the said screws.

One of the half links, in the example the halflink 12 at the bushing side, has a seat 1 6 for coupling with a bushing (not shown in the Figure) and the other half-link, in the example the halflink 11 at the pin side, has a seat 1 7 to be coupled to a pin (not shown in the Figure); the above said bushings and pins can be inserted and held in their operative positions by force fitting them in their seats or by any other suitable means.

In addition, the above half-links have sides 1 8 and 19 on opposite sides of the junction line, so shaped and machined as to form, upon assembiing the link, two planar and parallel surfaces. The side portion 18 of the half-link 11 operates as a rolling race (upon track tension wheels and rollers) for the assembled connection link, whilst the side portion 1 9 of the half-iink 1 2 operates as an attachment plane for the shoe 1 5 of the assembled connection link, said attachment being effected by screws 14 which connect the whole assembly as above described.

Referring now to Figure 2, the portion of the bushing side connection half-link 12 which is opposite both to the portion including the bushing seat 16 and to the area needed for engagement with the standard link adjacent to the connection link, has a substantial increase in its cross sectional size and consequent proportional increase in its mass.

In the same manner, referring now to Figure 4, also the portion of the pin side half-link 11 which is opposite to both the end portion including the pin seat 1 7 and the area needed for engagement with the standard link adjacent to the connection link has a similar substantial increase in its cross sectional size and consequent proportional increase in its mass.

This increase in mass affects the whole central portion of the assembled connection link and it is designed to contemporaneously obtain different results, such as a broader distribution of the very severe stresses due to the track chain tension within the body of the link, a base for bearing the half-links on each other along the rectilinear end segments of the junction line 13 that is as large as possible, in order to reduce the unit stress acting upon the material due to the weight of the portion of the vehicle lying on the link and to the load exerted by screws 14.

Furthermore, the above said increase in cross sectional thickness results into a stiffer coupling between the two half-links in the longitudinal plane of the assembled link and it enables the contact surface of key 22 to withstand the specific pressure in the engagement area of the two parts, in the central portion of the junction line 13.

Referring again to Figure 1, it may be observed that the terminal segments of the end portions of the junction line 13 change their direction so as to intersect almost perpendicularly the external side portions 1 8 and 19 of the assembled connection link.

The purpose of the above arrangement is to obtain a greater strength in the corner portions formed by the intersection of junction line 1 3 with the external side portions 1 8 and 19, thereby reducing the chipping possibility thereof due to their brittleness. In addition, this arragenemt enables a slight increase in the material thickness outwardly of the force fit area with the pin and the bushing.

Furthermore, the junction line 1 3 corresponds to a symmetrical outline (reversed for the two half-links) that can be obtained by means of a single machining step on both half-links, by keeping them closed to each other, after having turned one of them upside down and round and after having carefully aligned them.

This invention has been described in its preferred embodiment; however, it is to be understood that changes can be made therein by those skilled in the art without departing from the scope of the appended claims.

Claims (8)

Claims

1. A connection link for chains comprising two twin half-links coupled along a junction line passing between two offset side segments lying in parallel planes, and diagonally extending with respect to the link axis and of a coupling member designed to operate as a connection part, adapted to withstand tension stresses, housed in a seat located at the central portion of said junction line.

2. A link according to claim 1, wherein said coupling member is a shaped metal key provided with an insertion bevel and engaged by force fitting into a seat provided by recesses formed respectively in the half-links.

3. A link according to claim 1 or 2, wherein the coupling of the two twin haif-links is obtained by means of two parallel set screws; the two screws being passed through holes provided in one half link and are tightened within blind threaded holes provided in the other half link.

4. A link according to claim 3, for a chain track, wherein one of the haif-links is adapted to have mounted thereon a track shoe.

5. A link according to claim 4, wherein said set screws are first received in the half link to mount the shoe.

6. A link according to claim 4, wherein the distance between said set screws is the same as the distance between the screws of other links of the chain track, so as to enable a standard shoe to be mounted on the respective half-link.

7. A link according to claims 1 to 6, wherein each half-link provides a planar said side face such that when assembled, the two sides are parallel and wherein said mixtilinear junction profile of the half-links extends parallel to the junction axes of the link and ends in a portion adjacent the two planar sides along a direction substantially perpendicular to said sides.

8. A link according to claims 1 to 7, wherein the two half-links at their central portions have a substantial increase in their cross sectional thickness.

9oA connection link for chains substantially as hereinbefore described with reference to the accompanying drawings.