Fixed Guard for Rotating Joints

1. Field of the Invention

This invention is concerned with a device for protecting a wide angle joint associated with a driveshaft for driving agricultural implements or the like, the device comprising a hollow guard at least partially covering the joint. The guard may be at least partially conical.

2. Description of Prior Art

Such hollow guards are known from West German Patent Specification No. 35 09 128 and its British equivalent No. 2173881, for example, and serve to protect rotating joints or driveshafts of power take-off shafts. The joint angles may be very large so that there may occur frictional wear between the hollow guard and joint. In the case of the aforementioned prior art design, the hollow guard is held at a distance from the joint by a bearing ring, with the bearing ring being capable of being compressed by a certain amount and thus being able to conform to the articulation movements. However, these compressional movements have been found to be insufficient.

It is the object of the present invention to provide a hollow guard of the aforementioned type which permits large joint angles and which avoids the joint contacting the interior of the hollow guard.

The invention provides a device for protecting a wide angle joint associated with a driveshaft for driving agricultural implements or the like, the device comprising a hollow guard at least partially covering the joint, wherein the device also comprises a sliding ring mounted on the joint, the ring being axially movable in the guard, the hollow guard clears the joint by a distance determined by the sliding ring, and the hollow guard, at an axial inward end thereof, comprises a flexible convoluted tube covering the joint and joining the remainder of the guard at an edge which is contactable by the ring.

In this way, it is possible to provide a fixed single-part hollow guard in which a driveshaft or the joint of a driveshaft may be articulated by any angle required. The device comprises a flexible region which can be bent if necessary. The sliding ring holds the hollow guard at a distance from the joint and, if required, bends the flexible part.

To ensure safe and interference-free guidance, the outer circumference of the sliding ring may be provided with guiding grooves engaged by radially inwardly pointing and axially extending pulling ribs in a cylindrical part of the hollow guard, with the ribs movably guiding the sliding ring.

Furthermore, it is proposed that the flexible convoluted tube should be deformed asymmetrically when the sliding ring contacts the contact edge.

For lubricating the sliding ring, it may be provided with a radially outwardly pointing lubricating nipple, the lubricating nipple projecting through an axially extending aperture in a cylindrical part of the guard.

An illustrative embodiment of a device according to the invention is illustrated in the attached drawings and is described in more detail below.

FIG. 1 is a longitudinal section through a joint including a device according to the invention;

FIG. 2 shows the joint according to FIG. 1 in an articulated condition, with a flexible convoluted tube of the device asymmetrically deformed;

FIG. 3 shows a cylindrical part of a hollow guard of the device shown in FIGS. 1 and 2 with guiding slot as well as a lubricating nipple of a sliding ring guided in a guiding slot; and

FIG. 4 is front view of the hollow guard of the device shown in FIGS. 1 and 2.

As illustrated in FIG. 1, a driveshaft 7 for driving agricultural implements or the like is covered by a protective tube 4 which is provided with a protective cap 3. The driveshaft 7 is associated with a wide angle joint 8 which is protected by a protective device according to the invention. The device comprises a hollow gaurd which comprises a flexible convoluted tube 6 which is plugged on to, preferably slid on to and held on, the protective cap 3. The flexible convoluted tube 6 joins at its axially outward end on to the remainder of the hollow guard of the device which has a cylindrical portion 11 and an axially outward conical portion 1. The cylindrical portion 11 surrounds the central part of the double joint 8. A sliding ring 2 of the device is mounted for rotation in a recess 14 of a central yoke 9 of the joint 8 and, as can be seen in FIG. 4, is held and guided by axially extending pulling ribs 5 of the cylindrical part 11 which extend into guiding grooves 15 in the ring 2. The guard 1, 6, 11 clears the joint 8 by a distance determined by the ring 2.

If the joint 8 is articulated at extreme angles, the sliding ring 2, comes to rest between the cylindrical part 11 and the flexible convoluted tube 6, as shown in FIG. 2. The ring 2 contacts a contact edge 10 of the tube 6, adjacent the part 11 and extending radially inwardly relative to the cylindrical part 11. The sliding ring 2, thus, rests against the flexible convoluted tube 6 and axially compresses it in this region. On the opposite side, the convoluted tube 6 is extended.

The sliding ring 2 holds the portions 1 and 11 of the guard in an approximately constant position relative to the outer circumference of the joint 8 and prevents the joint 8 from running against the interior of the guard.

As can be seen in FIG. 3, a lubricating nipple 13 extends through an aperture 12 in the cylindrical part 11 of the guard for the purpose of lubricating the sliding ring 2.

As shown in FIG. 4, the inside of the guard portion 11 is provided with pulling ribs 5 in which the sliding ring 2 is axially movable.