GB1590134A

GB1590134A - Power take off assemblies

Info

Publication number: GB1590134A
Application number: GB2360977A
Authority: GB
Original assignee: ATKINSONS CLITHEROE Ltd
Current assignee: ATKINSONS CLITHEROE Ltd
Priority date: 1977-06-03
Filing date: 1977-06-03
Publication date: 1981-05-28
Also published as: FR2393226A1; NL7800483A; FR2393226B3

Description

(54) IMPROVEMENTS IN AND RELATING TO POWER TAKE OFF ASSEMBLIES (71) We, ATKINSON'S OF CLITHEROE LIMITED, a British Company, of Kendal Street, Clitheroe, Lancashire, BB7 INZ, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to safety guards for machinery, such as power-take-off (P.T.O.) assemblies, and to P.T.O. assemblies consisting of a P.T.O. shaft having a P.T.O. guard surrounding the shaft and bearing means for securing the guard to the shaft. Such a P.T.O. assembly is a drive coupling commonly used to connect the engine of a tractor to a piece of separate machinery which is to be driven from the tractor engine.

According to the present invention there is provided a safety guard assembly, for a rotary member having a part thereof formed with an annular groove coaxial with the member and capable of forming the inner race member of a bearing, the guard assembly comprising an outer race member, a plurality of bearing members retained with a guide member with limited freedom for radial movement, said bearing members being surrounded by said outer race member, a sleeve-shaped guard for surrounding the rotary member, the outer race member having a plurality of recesses therein corresponding in number and spacing to the bearing members into which the respective bearing members can be moved, and from which the respective bearing members are excluded upon rotational dsplacement of the outer race member relative to the guide member to bring said bearing members into and out of register with said recesses, means mounted on the guard and supporting the outer race and guide members relative to the guard, and operating means accessible from outside the guard and connected to one of said guide and outer race members for effecting rotational movement of one of said members relative to the other.

The present invention also provides a P.T.O. assembly comprising a rotary member having a part thereof formed with a radially outwardly-facing annular groove, a tubular safety guard and a bearing supporting the guard relative to the rotary member, the bearing comprising an outer race member, and a plurality of bearing members, the groove in said part of the rotary member forming the inner race member, the bearing further comprising a guide member connected to the guard for locating the bearing members relative to one another in a circumferential direction yet permitting limited radial movement of the bearing members, the outer race member having a plurality of recesses therein corresponding in number and spacing to those of the bearing members into which the respective bearing members can be moved and from which the respective bearing members are excluded upon rotational displacement of the outer race member relative to the guide member to bring said baring members into and out of register with said recesses, means for supporting the outer race member and the guide member relative to the guard, and operating means accessible from outside the guard, connected to one of said guide and outer race members, and movable to effect said relative rotational displacement between said guide member and said outer race member thereby to cause the bearing members to be engaged with or to permit the bearing members to be disengaged from the groove of the inner race member.

A P.T.O. assembly in accordance with the invention will now be described in detail, by way of example only, with reference to the accompanying drawings in which: Figure 1 is a longitudinal sectional view of the P.T.O. assembly consisting of a P.T.O. shaft, a P.T.O. guard, and releasable locking means for securing the guard to the shaft; Figure 2 is a longitudinal sectional view of the left-hand end portion of the assembly of Figure 1 showing the locking means in a released position; Figure 3 and Figure 4 are sections on the lines III-III of Figure 2 and IV-IV of Figure 1 respectively; Figure 5 is a section on the line V-V of Figure 1; Figure 6 is a plan view of the right-hand end of the P.T.O. guard of Figure 1; Figure 7 is a fragmentary sectional view showing a modification of the construction shown in Figure 2, the shaft and bearing members being omitted to clarify the construction; Figure 8 is a fragmentary sectional view showing another modification of the construction shown in Figure 2, the shaft and bearing members being omitted to clarify the construction, and Figure 9 is a cross-section on the line IX-IX of Figure 8 but showing the shaft and bearing members in position.

As seen in Figure 1, the P.T.O. assembly comprises a P.T.O. shaft formed by a tubular outer shaft 10 terminating at its right hand end in a universal joint 11, an inner shaft 12 splined within and co-axially movable within the tubular outer shaft 10, the inner shaft 12 terminating at its lefthand end in a universal joint 13, and a twopart P.T.O. guard 14 forming a sleeve around the shaft. This guard comprises an outer tubular portion 14a secured at its right-hand end to a first bell-shaped portion 14b, and an inner tubular portion 14c fitting telescopically within the outer tubular portion 14e and connected at its left-hand end to a second bell-shaped portion 14d. The telescoped tubular portions 14a, 14c, of the guard form a sleeve around the telescoped portions of the shaft. The bell-shaped portions 14b, 14d of the guard extend around the two universal joints 11, 13 of the shaft.

The tubular portion and the bell-shaped portion in each part of the guard fit slidingly together and are secured together, for example by adhesive, rivets or welding. A locking device 15 is associated with each part of the guard to lock that part of the guard to the associated part of the shaft.

Since the two locking devices 15 are substantially identical a description will be given only of the left-hand locking device as seen in Figure 1 for connecting the inner shaft 12 with the associated part of the guard. This locking device comprises a ball bearing cage l5a forming a guide member for, for example, six balls 15b spaced at 60 intervals around the cage, each ball having limited freedom for movement in a radial direction within the cage. The cage is fitted around a collar shaped portion 12a of the shaft closely adjacent the universal joint, this collar portion having a plain cylindrical surface portion 12b of the shaft closely adjacent the universal joint, this collar portion having a plain cylindrical surface portion 12b terminating, in an axially-outward direction, in a peripheral groove 12c and forming an inner race member of the bearing. The cage fits around the collar portion 12a and is movable axially between the plain cylindrical surface portion 12b, on which the balls can roll when they are in a radially-outwardly-displaced position within the cage, and the groove 12c, in which the balls can engage when they are in a radially-inwardly-displaced position in the cage. A guide tube 16 is attached at one end to the axially-inner end of the cage 15a and, at its other end, fits within the inner tubular portion 1 4c of the guard to maintain the bearing cage perpendicular to the axis of the assembly. The tube 16 can be held in position in the guard by rivets such as 17, or other means.

Surrounding the bearing cage is a locking ring 1 sic having a number of recesses 15d (Fig. 4) corresponding to the number and spacing of the balls. The inner diameter of the locking ring 15e is such that the ring fits closely around the bearing cage and forms an outer race member of the bearing.

Consequently, when the recesses 15d are out of alignment with the balls, the balls are held in a position in which they project inwardly through the inner periphery of the cage. However, when the recesses 15d are aligned with the balls, (Fig. 3) the balls can move radially outwardly through the outer periphery of the cage.

It will thus be evident that when the balls 15b are aligned with the groove 12c in the collar 1 2a of the shaft, the locking ring 1 sic can be rotated to a locking position (Fig.

4) in which the recesses are out of alignment with the balls, and the balls are thereby locked in a position in which they engage within the groove and cannot escape from the groove. Upon rotating the locking ring to an unlocked position in which the recesses 15d are aligned with the balls, the balls are free to move out of the groove, and will be forced to do so upon axial movement of the cage 15a away from the groove 12c, to lift the balls out of the groove on to the adjacent plain cylindrical surface 12b of the collar portion 12a. Movement of the bearing cage is effected by an actuating handle 15e which is secured to the locking ring 1 sic and protrudes through an opening in the adjacent bell shaped portion of the guard. The outer end of the actuating handle is located between two spring fingers 15f (See Figs. 5 and 6) rivetted to the dutside of the bell section of the guard, the spring fingers preventing unintentional rotation of the handle of the cam ring away from its locked state. If however one of the spring fingers is depressed by a suitable tool (not shown), the handle can then be rotated about the axis of the shaft to rotate the locking ring from the locked position into the unlocked position. There after axial movement of the handle will release the balls from the collar and permit the inner shaft to be withdrawn from the adjacent part of the guard and from the outer shaft. In a similar manner, release of the locking device which holds the outer shaft to the other part of the guard will enable the outer shaft to be withdrawn from this part of the guard.

Although the locking device has been described and illustrated as including spring fingers for holding the handle, other means releasable by a tool can alternatively be used. For example a spring finger could be mounted on the guard to extend into locking engagement with the ring 15a and be flexed out of engagement with ring 15a by a suitable tool.

In the modification shown in Figure 7 a tube 116, by which a cage 115a is supported on the guard, is fitted internally of a bellshaped portion 1 14d of the guard and externally of the adjacent outer tubular portion 11 4c of the guard. The tube 116 is formed integrally with teeth 11 6a on its inner surface and 11gob on its outer surface for locking engagement with apertures formed in the overlapping regions of the tubular portion 1 14c and bell-shaped portion 1 14d to lock the parts together. This connecting means forms an alternative to rivetting or welding. The inner surface of tube 116 is formed with steps to fit either the outer tubular portion 1 14c or the inner tubular portion 1 14a of the guard, and the teeth 11 6a are provided on each of the steps.

The cage 115a is surrounded by a locking ring 115c of a similar shape to, and designed to serve the same purpose as, the locking ring 1 sic of the first embodiment.

In a further modification shown in Figures 8 and 9, a bell-shaped portion 214d of the guard is formed integrally with an axial tubular sleeve 214e having, integral with the inner face thereof, two annular rows of radially inwardly directed teeth 214f and 214g. The teeth 21 4g are located on a surface dimensioned to fit the inner tube 214c whereas the teeth 214f are located on an outwardly stepped surface dimensioned to fit the outer tube 214a. Consequently either tube 214a or 214c, formed adjacent its end with apertures 214h matching the teeth, can be pushed into the tubular sleeve 214e and after compression of the tube to slip over the teeth, will be locked by engagement of the appropriate row of teeth in the apertures 214h of the tube. The teeth are champered on one side to facilitate insertion, but to resist withdrawal of the tube.

Mounted within the inner end of the bell shaped portion is a bearing cage 21 spa having an axial extension 215b which engages in the opposite end of the tubular sleeve 21 4e and is locked therein by a third row of teeth 214j, integral with the inner surface of the sleeve, which engage in apertures 215c in the extension 215b.

Surrounding the cage 215a is a locking ring 215d which fits slidingly between the inner surface of the bell-shaped portion 21 4d and the external surface of the cage 21 spa. This locking ring (as shown in Figure 9) is formed with a number of recesses 215e spaced apart around its inner surface for the reception of balls 215f mounted in the cage, as in the first embodiment described above. The locking ring is formed externally with a knob 215g which protrudes through a slot 214k in the bell-shaped portion 214d, the slot being of a length sufficient to permit rotation of the knob about the axis of the bearing to bring the balls into or out of register with the recesses.

WHAT WE CLAIM IS: 1. A safety guard assembly, for a rotary member having a part thereof formed with an annular groove coaxial with the member and capable of forming the inner race member of a bearing, the guard assembly comprising an outer race member, a plurality of bearing members retained with a guide member with limited freedom for radial movement, said bearing members being surrounded by said outer race member, a sleeve-shaped guard for surrounding the rotary member, the outer race member having a plurality of recesses therein corresponding in number and spacing to the bearing members into which the respective bearing members can be moved and from which the respective bearing members are excluded upon rotational displacement of the outer race member relative to the guide member, to bring said bearing members into and out of register with said recesses, means mounted on the guard and supporting the outer race and guide members relative to the guard, and operating means accessible from outside the guard and connected to one of said guide and outer race members for effecting rotational movement of one of said members relative to the other.

2. A P.T.O. assembly comprising a rotary member having a part thereof formed with a radially outwardly-facing annular groove, a tubular safety guard and a bearing supporting the guard relative to the rotary member, the bearing comprising an outer race member, and a plurality of bearing members, the groove in said part of the rotary member forming the inner race member, the bearing further comprising a guide member connected to the guard for locating the bearing members relative to one another in a circumferential direction

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. after axial movement of the handle will release the balls from the collar and permit the inner shaft to be withdrawn from the adjacent part of the guard and from the outer shaft. In a similar manner, release of the locking device which holds the outer shaft to the other part of the guard will enable the outer shaft to be withdrawn from this part of the guard. Although the locking device has been described and illustrated as including spring fingers for holding the handle, other means releasable by a tool can alternatively be used. For example a spring finger could be mounted on the guard to extend into locking engagement with the ring 15a and be flexed out of engagement with ring 15a by a suitable tool. In the modification shown in Figure 7 a tube 116, by which a cage 115a is supported on the guard, is fitted internally of a bellshaped portion 1 14d of the guard and externally of the adjacent outer tubular portion 11 4c of the guard. The tube 116 is formed integrally with teeth 11 6a on its inner surface and 11gob on its outer surface for locking engagement with apertures formed in the overlapping regions of the tubular portion 1 14c and bell-shaped portion 1 14d to lock the parts together. This connecting means forms an alternative to rivetting or welding. The inner surface of tube 116 is formed with steps to fit either the outer tubular portion 1 14c or the inner tubular portion 1 14a of the guard, and the teeth 11 6a are provided on each of the steps. The cage 115a is surrounded by a locking ring 115c of a similar shape to, and designed to serve the same purpose as, the locking ring 1 sic of the first embodiment. In a further modification shown in Figures 8 and 9, a bell-shaped portion 214d of the guard is formed integrally with an axial tubular sleeve 214e having, integral with the inner face thereof, two annular rows of radially inwardly directed teeth 214f and 214g. The teeth 21 4g are located on a surface dimensioned to fit the inner tube 214c whereas the teeth 214f are located on an outwardly stepped surface dimensioned to fit the outer tube 214a. Consequently either tube 214a or 214c, formed adjacent its end with apertures 214h matching the teeth, can be pushed into the tubular sleeve 214e and after compression of the tube to slip over the teeth, will be locked by engagement of the appropriate row of teeth in the apertures 214h of the tube. The teeth are champered on one side to facilitate insertion, but to resist withdrawal of the tube. Mounted within the inner end of the bell shaped portion is a bearing cage 21 spa having an axial extension 215b which engages in the opposite end of the tubular sleeve 21 4e and is locked therein by a third row of teeth 214j, integral with the inner surface of the sleeve, which engage in apertures 215c in the extension 215b. Surrounding the cage 215a is a locking ring 215d which fits slidingly between the inner surface of the bell-shaped portion 21 4d and the external surface of the cage 21 spa. This locking ring (as shown in Figure 9) is formed with a number of recesses 215e spaced apart around its inner surface for the reception of balls 215f mounted in the cage, as in the first embodiment described above. The locking ring is formed externally with a knob 215g which protrudes through a slot 214k in the bell-shaped portion 214d, the slot being of a length sufficient to permit rotation of the knob about the axis of the bearing to bring the balls into or out of register with the recesses. WHAT WE CLAIM IS:

1. A safety guard assembly, for a rotary member having a part thereof formed with an annular groove coaxial with the member and capable of forming the inner race member of a bearing, the guard assembly comprising an outer race member, a plurality of bearing members retained with a guide member with limited freedom for radial movement, said bearing members being surrounded by said outer race member, a sleeve-shaped guard for surrounding the rotary member, the outer race member having a plurality of recesses therein corresponding in number and spacing to the bearing members into which the respective bearing members can be moved and from which the respective bearing members are excluded upon rotational displacement of the outer race member relative to the guide member, to bring said bearing members into and out of register with said recesses, means mounted on the guard and supporting the outer race and guide members relative to the guard, and operating means accessible from outside the guard and connected to one of said guide and outer race members for effecting rotational movement of one of said members relative to the other.

yet permitting limited radial movement of the bearing members, the outer race member having a plurality of recesses therein corresponding in number and spacing to those of the bearing members into which the respective bearing members can be moved and from which the respective bearing members are excluded upon rotational displacement of the outer race member relative to the guide member to bring said bearing members into and out of register with said recesses, means for supporting the outer race member and the guide member relative to the guard, and operating means accessible from outside the guard, connected to one of said guide and outer race members, and movable to effect said relative rotational displacement between said guide member and said outer race member thereby to cause the bearing members to be engaged with or to permit the bearing members to be disengaged from the groove of the inner race member.

3. An assembly according to claim 2 wherein the bearing members are balls and the guide member forms a cage for the balls.

4. An assembly according to any preceding claim wherein the means for supporting the outer race and guide members comprise a tube connected between the guide member and the guard, the outer race member being supported by said bearing members on the guide member.

5. An assembly according to any one of claims 1 to 3 wherein said operating means comprise a handle extending from the outer race or guide member outwardly through the guard.

6. An assembly according to claim 5 including releasable locking means for locking the handle in either of two positions corresponding respectively to the bearing members being in register and out of register with the recesses of the outer race member.

7. An assembly according to claim 6 wherein said locking means are adapted to be locked or unlocked only by the use of a tool.

8. A safety guard assembly or a P.T.O.

assembly substantially as herein described with reference to the accompanying drawings.