GB1562778A - Resilient shaft coupling - Google Patents

Description

(54) RESILIENT SHAFT COUPLING (71) We FORD MOTOR COMPANY LrxjTnD, of Eagle Way, Brentwood, Essex CM13 3BW, a Brtish Company, 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:- The present invention relates to a resilient shaft coupling in the form of a polygonal ring including a plurality of rubber blocks connected to form said ring and metal fittings connected one to each corner of said ring Elastic shaft couplings of the kind intro- ductorily described are already known in a plurality of forms.

German Patent 1 284 717 disclosed an elastic shaft coupling without any centring facility, and UK Patent 1 007 395 disclosed an elastic shaft coupling having a centring facility.

The known elastic shaftcoulings of the kind introductorily described, all exhibit the drawback that because of the compressive reloading of the rubber pillars, required tor reliable functioning, they have to be attached in the relaxed state with one hub spider and individual fixing components, by a vulcanising operation. whereafter, by means of a clamping band surrounding the shaft coupling, the rubber pillars have to be given the requisite compressive preload before the vuloanised-in fixing components can be attached by nuts and bolts to the arms of a shaft spider. After the assembly operation performed in this manner, the clamping band surrounding the shaft coupling must be removed so that the coupling is ready for use.

The application of the clamping band, the attaching of the fixing components through the agency of nuts and bolts, to the arms of the shaft spider, and the subsequent removal of the clamping band, represent a considerable outlay in terms of labour and material.

According to the invention there is provided a resilient shaft coupling in the form of a polygonal ring comprising an even number of rubber blocks connected to form said ring and metal fittings connected one to each corner of said ring, wherein alternate fittings in the ring consists each of a free end portion of an arm on a hub spider common to said alternate fittings and the remaining fittings consist each of a free end portion of an arm of an individual sector component of a shaft spider, said shaft coupling being assembled by locating the free end portions of the arms on the hub spider on a common pitch circle and locating the free end portions of said sector components on a common pitch circle of a diameter greater than the diameter of the first named pitch circle, displacing the free end portions of said sector components towards the centre of the ring thereby compressing their associated rubber blocks and bringing together said individual sector components, and joining together said sector components by welding, bonding or the like to form a complete shaft spider.

The elastic shaft coupling embodying the invention can be formed without any centring facility ar with a centring facility.

The invention will now be described by way of example with reference to the accompanying drawings, in which: Figure 1 illustrates a vertical section of a resilient shaft coupling in accordance with the invention: and Figure 2 illustrates an elevational view in the direction of the arrow II shown in Figure 1.

The elastic shaft coupling shown in the Figures 1 and 2 includes a hub spider having three arms 2, six rubber blocks 3 and three sector components 5 each having an arm 4. The sector components when connected together form a complete shaft spider 6.

The hub spider 1, has a centring sleeve 7 made of elastic synthetic material, generally harder than the material of the rubber pillars. A centring spigot 8 is located in the sleeve. The spigot 8 is attached in the shaft spider 6 in a suitable fashion by welding it into a bore of the final, complete shaft spider 6.

The blocks 3 are connected together to form a polygonal ring by vulcanising the ends of the rubber blocks. During vulcanising operation the free ends of the arms 2 are attached to alternate corners of the ring, one at each of said alternate corners and located between the ends of the pillars to be vulcanised together at that corner.

Similarly the arms 4 of the sector components 5 are attached one to each of the remaining corners of the ring. The arms 4 of the sector components 5 are arranged during vulcanising at a larger radial interval from the axis of the shaft coupling than the free ends of the arms 2 of the hub spider 1. The polygonal ring formed in this way thus substantially exhibits the irregular shape disclosed in U.K. Patent 1007 395.

The free end portions of arms 2 are located in said ring on a common pitch circle.

Similarly the free end portions of the arms 4 of the individual sector components 5 are located on a common pitch circle of a diameter greater than the diameter of the first named pitch circle. The arms 4 of the sector components 5 are displaceable towards the centre of the ring to thereby put under compression their associated rubber blocks and and bring together the sector components 5 so that they can be joined together by welding, bonding or the like to form a complete spider.

After vulcanising, the shaft coupling, which is then in the relaxed state, is placed in a fixture or a jig where the arms 4 of the sector components 5, said arms being at a larger interval from the axis of the shaft coupling, are moved into their predetermined, inner, radial position so that the rubber pillars 3 are given the requisite compressive preload of about 10%, the individual sector components 5 coming into abutment with one another through their connecting surfaces. In this position, the individual sector components 5 are secured to one another by welding, bonding or the like.

After removal of the shaft coupling from the preloading and connecting jig or fixture, it possesses the requisite rubber preload and there is no need to apply a clamping band in order to maintain the preload.

The free ends 9 and 10 of hub and shaft spiders 1 and 6 respectively, will preferably be so designed that they can be attached to the appropriate connecting parts of a set of shafts through interlocking connections, e.g.

hub bores or shaft stubs having a splined shaft profile. The free ends 9 and 10 of the hub and shaft spiders 1 and 6 respectively, however, can also be so designed in association with the connecting parts of the set of shafts, that for example the free end 10 of the shaft spider 6 can be connected to a propeller shaft tube by friction welding.

The present invention, makes it possible to achieve considerable reduction in cost for large-scale mass production of shaft couplings since the outlay in terms of labour and material hitherto required for preloading and attachment of the shaft coupling, is substantially reduced.

WHAT WE CLAIM IS: 1. A resilient shaft coupling in the form of a polygonal ring comprising an even number of rubber blocks connected to form said ring and metal fittings connected one to each corner of said ring, wherein alternate fittings in the ring consist each of a free end portion of an arm on a hub spider common to said alternate fittings, and the remaining fittings consist each of a free end portion of an arm of an individual sector component of a shaft spider, said shaft coupling being assembled by locating the free end portions of the arms on the hub spider on a common pitch circle and locating the free end portions of said sector components on a common pitch circle of a diameter greater than the diameter of the first named pitch circle, displacing the free end portions of said sector components towards the centre of the ring thereby compressing their associated rubber blocks and bringing together said individual sector components, and joining together said sector components by welding, bonding or the like to form a complete shaft spider.

2. A shaft coupling as claimed in Claim 1, wherein the individual sector components are formed from a single shaft spider, which after machining, is cut to form corresponding sector components.

3. A shaft coupling as claimed in Claim 1, wherein the individual sector components are formed from individual forgings, castings, die-castings or sheet metal pressings, manufactured to the requisite accuracy.

4. A resilient shaft coupling substantially as hereinbefore described with reference to the accompanying drawings.

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

Claims (4)

**WARNING** start of CLMS field may overlap end of DESC **. The hub spider 1, has a centring sleeve 7 made of elastic synthetic material, generally harder than the material of the rubber pillars. A centring spigot 8 is located in the sleeve. The spigot 8 is attached in the shaft spider 6 in a suitable fashion by welding it into a bore of the final, complete shaft spider 6. The blocks 3 are connected together to form a polygonal ring by vulcanising the ends of the rubber blocks. During vulcanising operation the free ends of the arms 2 are attached to alternate corners of the ring, one at each of said alternate corners and located between the ends of the pillars to be vulcanised together at that corner. Similarly the arms 4 of the sector components 5 are attached one to each of the remaining corners of the ring. The arms 4 of the sector components 5 are arranged during vulcanising at a larger radial interval from the axis of the shaft coupling than the free ends of the arms 2 of the hub spider 1. The polygonal ring formed in this way thus substantially exhibits the irregular shape disclosed in U.K. Patent 1007 395. The free end portions of arms 2 are located in said ring on a common pitch circle. Similarly the free end portions of the arms 4 of the individual sector components 5 are located on a common pitch circle of a diameter greater than the diameter of the first named pitch circle. The arms 4 of the sector components 5 are displaceable towards the centre of the ring to thereby put under compression their associated rubber blocks and and bring together the sector components 5 so that they can be joined together by welding, bonding or the like to form a complete spider. After vulcanising, the shaft coupling, which is then in the relaxed state, is placed in a fixture or a jig where the arms 4 of the sector components 5, said arms being at a larger interval from the axis of the shaft coupling, are moved into their predetermined, inner, radial position so that the rubber pillars 3 are given the requisite compressive preload of about 10%, the individual sector components 5 coming into abutment with one another through their connecting surfaces. In this position, the individual sector components 5 are secured to one another by welding, bonding or the like. After removal of the shaft coupling from the preloading and connecting jig or fixture, it possesses the requisite rubber preload and there is no need to apply a clamping band in order to maintain the preload. The free ends 9 and 10 of hub and shaft spiders 1 and 6 respectively, will preferably be so designed that they can be attached to the appropriate connecting parts of a set of shafts through interlocking connections, e.g. hub bores or shaft stubs having a splined shaft profile. The free ends 9 and 10 of the hub and shaft spiders 1 and 6 respectively, however, can also be so designed in association with the connecting parts of the set of shafts, that for example the free end 10 of the shaft spider 6 can be connected to a propeller shaft tube by friction welding. The present invention, makes it possible to achieve considerable reduction in cost for large-scale mass production of shaft couplings since the outlay in terms of labour and material hitherto required for preloading and attachment of the shaft coupling, is substantially reduced. WHAT WE CLAIM IS:

1. A resilient shaft coupling in the form of a polygonal ring comprising an even number of rubber blocks connected to form said ring and metal fittings connected one to each corner of said ring, wherein alternate fittings in the ring consist each of a free end portion of an arm on a hub spider common to said alternate fittings, and the remaining fittings consist each of a free end portion of an arm of an individual sector component of a shaft spider, said shaft coupling being assembled by locating the free end portions of the arms on the hub spider on a common pitch circle and locating the free end portions of said sector components on a common pitch circle of a diameter greater than the diameter of the first named pitch circle, displacing the free end portions of said sector components towards the centre of the ring thereby compressing their associated rubber blocks and bringing together said individual sector components, and joining together said sector components by welding, bonding or the like to form a complete shaft spider.

2. A shaft coupling as claimed in Claim 1, wherein the individual sector components are formed from a single shaft spider, which after machining, is cut to form corresponding sector components.

3. A shaft coupling as claimed in Claim 1, wherein the individual sector components are formed from individual forgings, castings, die-castings or sheet metal pressings, manufactured to the requisite accuracy.

4. A resilient shaft coupling substantially as hereinbefore described with reference to the accompanying drawings.