Protective device for a universal joint assembly

A universal joint assembly connecting a pair of shaft ends is provided with a protective boot having a bellows-like configuration defining circumferential folds and including a conical connecting portion. A connecting piece is provided for joining a protective tube of one of the shafts with the protective boot. The connecting piece includes a funnel-like extension partially projecting into the conical connecting portion of the protective boot and a rigid supporting ring engages about the protective boot. The supporting ring includes a conical part adapted to extend in embracing engagement over the conical connecting portion of the protective boot, the conical part extending to partially overlap with a funnel-like extension of the connecting piece. The supporting ring is formed with a bead which is directed radially inwardly into engagement with one of the folds of the protective boot, the bead being formed on one side with a conical surface to facilitate insertion of the boot into the supporting ring and on the opposite side with a hook-like shape for maintaining engagement within the fold.

The present invention relates generally to a protective device particularly 
for a universal joint between the ends of a pair of shafts which may 
constitute a drive shaft assembly connecting a tractor with an 
agricultural implement. 
More particularly, the invention relates to the type of assembly wherein a 
pair of telescopic protective tubes surround the shafts of the drive shaft 
assembly, with each of the protective tubes having an annular bearing 
member arranged at a respective end of at least one of the shafts which 
engages into an annular groove of a shank of the universal joint assembly, 
which may be a joint fork shank of the joint. A connecting piece is 
provided with through-holes for locking tongues provided for the bearing 
member and pointing radially outwardly and by means of which the 
respective protective tube is connected to a protective boot having a 
bellows-like configuration covering the joint. The connecting piece is 
provided with a funnel-like extension partially projecting into the 
protective boot and with a supporting ring arranged at the protective 
boot. 
Protective guard assemblies for a universal joint are known from the prior 
art, particularly U.S. Pat. No. 4,107,952. Such a protective guard 
assemblies comprise two protective boots which serve to cover a wide-angle 
universal joint and which have open ends facing each other. The boots are 
held with respect to each other by a supporting ring extending across both 
of the protective boots. 
However, disadvantages arise in this type of guard assembly in that the 
support described does not provide support against radial forces occurring 
in the area of the joint. Therefore, if the device is handled incorrectly, 
the protective assembly may be damaged. 
The present invention is directed toward provision of a protective device 
which will provide effective protection without affecting the angle of 
articulation of the joint even if the device is handled carelessly. The 
invention is also directed toward a device which is capable of remaining 
functional even when subjected to high radial and axial loads. 
SUMMARY OF THE INVENTION 
Briefly, the present invention may be described as a protective device for 
a universal joint assembly between two shafts wherein there is provided a 
pair of telescopic protective tubes (14, 15) surrounding at least one of 
the shafts, one of the tubes having an annular bearing member at a 
respective end of said at least one shaft which engages into an annular 
groove of a shank of the joint assembly, the protective device comprising 
a protective boot having a bellows-like configuration defining 
circumferential folds and including a conical connecting portion, a 
connecting piece having said bearing member connected thereto by means of 
which a respective protective tube is connected with said protective boot, 
said connecting piece including a funnel-like extension partially 
projecting into said conical connecting portion of said protective boot, a 
rigid supporting ring engaging about said protective boot and including a 
conical part adapted to extend in embracing engagement over said conical 
connecting portion of said protective boot, said conical part extending to 
partially overlap said funnel-like extension, and a bead directed radially 
inwardly extending from said supporting ring into engagement within one of 
said folds of said protective boot, said bead being formed on one side 
thereof with a conical surface to facilitate insertion of said protective 
boot into said supporting ring and on the opposite side thereof with a 
hook-like shape for maintaining engagement within said fold. 
An important advantage of the protective device in accordance with the 
invention is that the supporting ring may be fitted without the use of 
tools. 
Since the supporting ring and the funnel-like extension of the connecting 
piece partially overlap, the supporting ring is capable of withstanding 
high radial forces. If axial forces occur, the supporting ring is in a 
position of escaping elastically in the direction of the protective tube. 
Therefore, even if the protective device is handled incorrectly, it is 
unlikely that damage will occur. 
The various features of novelty which characterize the invention are 
pointed out with particularity in the claims annexed to and forming a part 
of this disclosure. For a better understanding of the invention, its 
operating advantages and specific objects attained by its use, reference 
should be had to the accompanying drawing and descriptive matter in which 
there is illustrated and described a preferred embodiment of the invention 
.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring now to the drawing, there is shown a protective device for a 
universal joint assembly connecting the ends of a pair of shafts, the 
device being particularly suitable for use in a drive shaft assembly 
connecting a tractor with an agricultural implement. A protective boot 1 
is arranged to extend over a connecting piece 9 by means of a connecting 
cone 12. The connecting piece 9 also supports a bearing ring 8 which, for 
the purpose of supporting the protective device, engages into an annular 
groove 11 of a shank of a part of the universal joint assembly; in the 
drawing, the part shown being a joint fork 10. 
In order to connect the supporting ring 6 to the protective device, the 
supporting ring 6 is slipped onto the protective boot 1 toward its open 
end from the side of the protective tube. 
The supporting ring 6 is formed with a conical part 7 and with an inwardly 
radially extending bead 4. The radially inwardly extending bead 4 has on 
one side thereof a conical surface 3 and on the opposite side thereof a 
hook-like part 5. 
Since the radially inwardly extending bead 4 of the supporting ring 6 is 
provided with the conical surface 3, facing toward the mounting direction 
of the ring 6 onto the boot 1, the supporting ring 6 may be slipped over 
the protective boot 1 quite easily without requiring the use of tools. In 
order to hold the supporting ring 6 more firmly when subjected to axial 
forces, the bead 4 is provided with the hook-like part 5 on the side 
thereof opposite the conical surface 3 which side faces the connecting 
piece 9 so that the bead 4 will grip firmly into a fold 2 of the 
protective boot 1 and thereby maintain its engagement within the fold. 
A funnel-shaped extension 13 is provided projecting into the connecting 
conical part 12 of the boot 1 with the extension 13 being partially 
overlapped by the conical part 7 of the supporting ring 6 so that the 
supporting ring is sufficiently supported against radial loads. 
While a specific embodiment of the invention has been shown and described 
in detail to illustrate the application of the inventive principles, it 
will be understood that the invention may be embodied otherwise without 
departing from such principles.