GB2047372A

GB2047372A - Safety guards for cardan shafts

Info

Publication number: GB2047372A
Application number: GB8007687A
Authority: GB
Original assignee: BONDIOLI E
Current assignee: BONDIOLI E
Priority date: 1979-04-11
Filing date: 1980-03-06
Publication date: 1980-11-26
Also published as: IT1165949B; GB2047372B; FR2454016B1; FR2454016A1; ES257547U; DE3013792A1; IT7909393A0; ES257547Y

Abstract

The guard comprises a telescopic tubular sheath 9,10 mounted on the shaft 1, and a funnel shaped cowl 14 at least at one end of the sheath. The funnel shaped cowl is composed of a more rigid, strong base part 141 which is mounted on the shaft and partly covers the end articulated joint 7 of the shaft, and a relatively more flexible replaceable terminal part 143 which completes the covering of the joint. The terminal part 143 may be snap-mounted on the part 141 and provided with a hole in its side which can be turned to coincide with a hole 155 in the part 141 to give access for lubrication. <IMAGE>

Description

SPECIFICATION Safety guards for cardan shafts The invention relates to a safety guard for Cardan shafts, comprising a telescopic tubular sheath mounted on the shaft, and a guard in the form of a cowl, i.e. funnel shaped or the like, at least at one end of the sheath.

The object of the invention is to provide a guard able to resist accidental radial loads in the end regions while allowing the necessary deformations when the shaft forms relatively large angles.

A further object of the invention is to provide guards which are easily adaptable to the requirements of individual applications.

According to the invention, for these and further objects which will be apparent to the expert, said guard in the form of a cowl, i.e.

funnel shaped or the like, is composed of a more rigid, strong base part which is mounted on the shaft and partly covers the end articulated joint of the shaft, and a relatively more flexible replaceable terminal part which completes the covering of the joint.

In practice, the flexible replaceable terminal part can be snap-mounted on to the base part.

In addition, it is advantageous for the replaceable terminal part to be able to rotate about and on the base part. In this case, each of the two parts of the funnel-shaped guard comprises a hole in the zone where they overlap, the hole arrangement being such that the two holes can be brought into avcoinciding position to allow access to and lubrication of the internal members, and can also be moved into an offset position in order to protect said internal members. In said overlapping and angular sliding zone, projections and cavities can be provided in order to establish relative angular positions between the two parts of the funnel-shaped guard.

The invention will be more apparent from the description and the accompanying drawing, which shows a non-limiting embodiment of the invention, and in which: Figure 1 is an overall view in partial longitudinal section of a Cardan shaft with the sheath; Figure 2 is an enlarged detail of Fig. 1; Figure 3 is an external view of a shaft with part of the terminal guard; Figure 4 is a cross-section on the line IV-IV of Fig. 3; Figure 5 is an end detail of the tubular sheath; Figures 6 and 7 show a mounting collar and its position on a joint; Figures 8 and 9 show one end of a guard with a different replaceable part, together with a separate view of a further different replaceable part; and Figures 10 and ii are separate local sections through the overlapping zones of the two component parts of the terminal guard or funnel or cowl.

As shown in the accompanying drawing, the reference numerals 1 and 3 indicate two tubular portions of non-circular cross-section, which can slide one in the other to constitute the telescopic shaft of a Cardan drive, of which two articulated transmission joints are indicated by 5 and 7. Drive shafts of this type are known for many uses, in particular but not exclusively for agriculture. These shafts must be protected by a safety guard to prevent the shaft being able to grip clothes or the like and thus drag and injure the operators. For this purpose, a telescopic tubular sheath is provided in two portions 9 and 10, which are combined with two terminal cowl or funnel shaped guards indicated overall by 1 2 and 14.

In particular, the funnel shaped guard, such as the guard 14, is mounted over the end of the sheath 10 by means of a flat ring collar 16, which forms part of the terminal funnel shaped guard, this latter being engaged by an annular ring 18 in a groove 20 formed on the shaft in the connection zone between the tubular part 1 and the fork 7A of the articulated joint 7. The ring 18 comprises an edge for engagement in the groove 20, and is held externally in a seat in the terminal guard 1 4.

The ring 1 8 is connected by screws 22 to the funnel shaped guard 14, and comprises two projections 24 and 26 which are accessible from the outside of the funnel shaped guard 14. The first projection 24 is arranged to allow a chain or another flexible member to be hooked thereon, and able to prevent the guard from being spontaneously dragged by the rotating shaft on which it is mounted. The other projection 26 is used for lubricating from the outside the groove 20 in which the ring 18 is engaged.

The collar 1 6 is engaged with the tubular sheath 10 (and the corresponding element of the opposite guard 14 is engaged with the tubular sheath 9) by forming tongues 30 substantially of tangential extension as shown in particular in Figs. 4 and 5. After the collar 1 6 has been mounted on the sheath 1, zones of the material of the sheath 1 are punched and permanently deformed so as to form the tongues, as shown in Fig. 4, thus causing the material of the collar 1 6 to deform, which becomes expanded possibly to the point of itself being punched through by the deformation of the tongues 30. Consequently, the simple formation and outward deformation of the tongues 30 give rise to coupling between the parts 10 and 14 and between the parts 9 and 12.

The tongues 30 can be double and opposite each other, and can be spaced apart so that a bridge 30A remains between them, together with a corresponding bridge in the material of the collar 16.

As can be seen particularly in Fig. 2 or 3, the funnel shaped guard or cowl or the like, indicated overall by 14, is constituted characteristically by two components, in particular a relatively more rigid base part 141 and a relatively more flexible replaceable part 143.

The base part 141 comprises the collar 1 6 at one end, and a projection 1 45 at the other end adjacent to a substantially cylindrical zone 146 lying between said annular projection 145 and an annular projection 147. A hole 149 is provided in said cylindrical zone. The flexible replaceable part 143 can be forcibly snap-mounted by way of its portion 151 over the cylindrical zone 146 between the projections 145 and 147, so that it abuts against the annular projection 147 and rests against the annular projection 145 by way of its shoulder 1 53. The part 143 comprises a hole 155 in the zone 151.

The rigid base part 141 ensures resistance to deformation even with a relatively large accidental axial load, while the flexible part 143 enables the terminal funnel-shaped or cowl guard to deform, as is necessary to allow the angular movements of the Cardan drive shaft protected by the sheath in question, when determined inclinations of the joint such as the joint 7 are exceeded.

The flexible part 1 43 is replaceable, and thus the guard for a Cardan shaft can be completed for any given case by means of the most suitable part 143 for the particular application of the shaft, according to the structures which lie adjacent to the drive shaft. This allows storage simplification and cost reduction in providing guards suitable for any application which can arise in practice.

The zone 1 51 of the flexible replaceable part 143 can be slid angularly relative to the zone 146 of the base part 141. This brings the two holes 149 in the base part 141 and 1 55 in the flexible replaceable part 143 into coinciding positions, to give access to the interior of the guard cowl for lubrication purposes. By then offsetting the two holes, access is then closed to the internal parts, so increasing protection of the internal members against penetration by foreign bodies, dust and the like.

By constructing the terminal funnel-shaped guards in two parts such as the parts 141 and 143, it is possible to obtain a resistance to radial loads which is particularly advantageous from the safety aspect, while at the same time providing the necessary flexibility for adaptation to the inclination of the shaft and consequently of the sheath which protects it. This is attained with the further advantage of being able to combine the base guard formed by the sheaths 9 and 10 and by the base parts 141 of the terminal cowl guards with one or another of a variety of flexible parts 143 which match the base part 141, to thus adapt to the most varied applications which can be encountered in practice.

Figs. 10 and 11 show projections 1 58 in the zone 146 of the part 141, and an inner cavity 161 opposite the hole 155 in the zone 151. The projections 158 together with the hole 1 55 and cavity 1 61 define a staggered position of the holes 1 55 and 149.

The drawing shows only one embodiment given by way of example only, and modifications can be made to the shapes and arrangements without leaving the scope of the inventive idea.

Claims

1. A safety guard for Cardan shafts, comprising a telescopic tubular sheath mounted on the shaft and a funnel-shaped or equivalent guard at least at one end of the sheath, characterised in that said funnel-shaped or equivalent guard is composed of a more rigid, strong base part which is mounted on the shaft and partly covers the end articulated joint of the shaft, and a relatively more flexi ble replaceable terminal part which completes the joint covering.

2. A guard as claimed in the preceding claim, characterised in that the flexible replaceable terminal part is snap-mounted on the base part.

3. A guard as claimed in the preceding claims, characterised in that the replaceable terminal part can be rotated about and on the base part, and the two parts of the funnelshaped guard each comprise a hole in the overlapping zone, the hole arrangement being such that the two holes can be brought into a coinciding position to allow access to and lubrication of the internal members, and can be offset to protect said internal members.

4. A guard as claimed in the preceding claims, characterised in that projections and cavities are provided in the overlapping angularly sliding zone in order to establish relative angular positions between the two parts of the funnel-shaped guard.

5. A guard for Cardan drive shafts, with a telescopic sheath and a funnel-shaped end, all as heretofore described and shown by way of example on the accompanying drawing.