GB2156483A - Drive coupling - Google Patents

Abstract

The invention relates to a drive coupling for transmitting rotary drive between a pair of co-axial shafts. The coupling comprises a pair of co-axial gear members (10, 11) having external gear teeth (14) in mesh with internal teeth (15) on a surrounding sleeve (16) which rotates with the gear members. Each gear member (10, 11) mounts a sealing ring support collar (18) which carries a sealing ring (20) in compressed engagement with a clamp (21) which is disposed around and in engagement with the sleeve. A pair of tongues (24) extend radially inwardly from the clamp, through slots (25) in the sleeve (16) to lie between adjacent ends of the gear members. This arrangement prevents disengagement of the sleeve from the gear members, as any axial sleeve movement results in the tongues contacting a gear. The coupling allows easy and quick assembly and disassembly. <IMAGE>

Description

SPECIFICATION Drive coupling This invention relates to a drive coupling, particularly for transmitting drive from a gearbox to the sprocket assembly of a flexible conveyor as used in coalmining.

According to the invention there is provided a drive coupling for transmitting rotary drive between a pair of co-axial shafts, comprising a pair of gear members, each intended to be connected to a respective one of said shafts, the gear members being received within a sleeve so as to rotate therewith, and so as to allow relative axial movement therebetween, and stop mneans disposed between adjacent ends of the gear members and engageable therewith to prevent axial disengagement of the sleeve from the gear members.

The invention will now be described by way of example with reference to the accompanying drawings, in which: Figure 1 is a part axial section through a drive coupling constructed in accordance with the invention, and Figure 2 is a part-sectional fagmentary end view of the coupling on a reduced scale.

The drive coupling shown in the Figures includes a pair of axially aligned gear members 10 and 11. Each gear member has an internal bore 1 2 provided with splines (not shown) to receive a splined end of a shaft onto which the gear member is to be fixedly received. A recess 13 is provided in an end face of each gear and a circlip is received in said recess, the circlip fitting on the end of the shaft to restrain axial separation between the gear member and its associated shaft.

Each gear member is formed with gear teeth 14 which mesh with internal teeth 1 5 in a surrounding sleeve 1 6. The sleeve extends axially over both gear members thereby ensuring that they rotate in unison.

Each gear member has an annular groove 1 7 in its outer surface and seated therein are the two halves of a sealing ring support collar 18 which extends radially out of the groove 1 7. In its outer surface is an annular groove 19 in which a sealing ring 20 is received. In its non-compressed state, the ring 20 extends slightly beyond the outer surface of the sleeve 16.

Around the periphery of the sleeve is provided a clamp 21 formed in two halves. Each half extends axially from one sealing ring to the other, as shown in Fig. 1 The two clamp halves are detachably connected and connection is by way of a threaded bolt 22 in aligned bores in each half. Only one of the connection arrangements is shown in Fig. 2.

The two halves of the clamp engage tightly down onto the sleeve 1 6 when the bolts 22 are fully received in the aligned bores, so that any axial movement of the sleeve occurs together with the clamp, i.e. there is no relative axial movement between the sleeve and the clamp.

When tightly engaged on the sleeve, the clamp compresses the sealing rings 20, so that the interior of the coupling forms an enclosed chamber to retain lubricant and prevent ingress of dirt. A plug 23 closes a lubrication port in the clamp.

In order to prevent the sleeve from sliding axially away from either gear member, each collar half has a tongue 24 welded in an aperture therein. As shown in the Figures each tongue is of rectangular shape having a reduced thickness at its free end. The tongues lie in a central radial plane through the clamp, being disposed diametrically opposite one another. Each tongue 24 extends inwardly from the clamp half through a complementarily shaped slot 25 in the sleeve 16 and terminates in the space between the teeth of the gear members 10, 11. The width of the tongue is reduced between the gear members to allow for mis-alignment of them, in use.

Each tongue is a tight fit in its associated slot 25. Thus relative axial movement between the sleeve and the clamp is prevented not only by the tight radial enagement of the clamp onto the sleeve, but also by the tight engagement of the tongues in the slots in the sleeves.

The outer sides of the sleeves 1 6 are bevelled to provide clearance from the respective adjacent collars 1 8. Although not shown accurately in Fig. 1, the smallest axial spacing of each bevelled side 26 of the sleeve 1 6 from the inner facing side surface 27 of the adjacent collar 1 8 is greater than the axial spacing of a side surface 28 of each tongue from a respective adjacent end face 1 0a or 11 a of the gear members. Accordingly, in use, any axial movement of the sleeve 16, and thus also the clamp 21 and tongues 24, results in a tongue surface 28 contacting a gear end face 1 0a or 11 a, so that axial disengagement of the sleeve from the gear members is prevented.With such contact between the tongues and a gear end face, the bevelled side 26 of each sleeve remains spaced from the side surface 27 of the adjacent collar 18.

In order to allow for slight mis-alignment of the shafts connected by the coupling, in use, each gear member is provided with slightly rounded gear teeth and the overlapping sleeve surface may be provided with a chamfer, thus enabling each gear member to deflect angularly with respect to the sleeve.

The coupling of the invention is radially and axially compact and effective, in use. Advantageously either gear member, associated support collar halves and sealing ring can be axially withdrawn from the coupling without having to split the clamp 21. Additionally removal of the clamp and support collar halves allows the coupling to be split by sliding the sleeve 1 6 either to the left or to the right to allow radially removal of the gear member. The coupling can thus be assembled and disassesmbled easily and quickly.

Further advantages are: i) axial angular movement of a gear member is less amplified by sealing onto the inside of the clamp as compared to known arrangements where a collar connected to the gear member extends over and seals over the sleeve, thus increasing the radial distance between the seal and the coupling axis. Thus with the coupling of the invention there is less wear of the sealing ring.

ii) the coupling can be completely dismantled by the removal of the two bolts only of the clamp.

iii) the sleeve is less effected by movement of a gear member than is the case with the arrangement referred to in i) above and can find it own natural movement path. Variations are possible from the embodiment described.

For example the clamp halves can be detachably connected in any suitable alternative manner. The tongues can be secured to the clamp halves in an alternative way or can even be integral with them.

Claims (10)

1. A drive coupling for transmitting rotary drive between a pair of co-axial shafts, comprising a pair of gear members, each intended to be connected to a respective one of said shafts, the gear members being received within a sleeve so as to rotate therewith, and so as to allow relative axial movement therebetween, and stop means disposed between adjacent ends of the gear members and engageable therewith to prevent axial disengagement of the sleeve from the gear members.

2. A device as claimed in claim 1, wherein a clamp is provided on the sleeve around the periphery thereof, so that there is no relative axial movement between the clamp and the sleeve.

3. A device as claimed in claim 2, wherein the clamp is formed in two detachably connected halves.

4. A device as claimed in claim 2 or claim 3, wherein the stop means is at least one tongue projecting from the clamp and through the sleeve and between said adjacent ends of the gear members.

5. A device as claimed in claim 4, wherein the tongue extends radially from the clamp, and passes through a complementarily shaped slot in the sleeve.

6. A device as claimed in claim 4 or claim 5, wherein a pair of diametrically opposed tongues are provided.

7. A device as claimed in any one of claims 2 to 6, wherein each gear member has an annular groove in its outer surface in which is seated a sealing ring support member, which carries a sealing ring compressed by the clamp.

8. A device as claimed in claim 7, wherein each support member is formed in two halves.

9. A device as claimed in claim 7 or claim 8 wherein there is a space between the ends of each of the sleeves and an adjacent face of the support member, which space is greater than the space between a side of the tongue and an adjacent gear end face.

10. A drive coupling substantially as here it before described with reference to and as shown in the accompanying drawings.