GB2211910A

GB2211910A - Chain wheel

Info

Publication number: GB2211910A
Application number: GB8825841A
Authority: GB
Inventors: Josef Rosegger
Original assignee: PENGG WALENTA KETTEN
Current assignee: PENGG WALENTA KETTEN
Priority date: 1987-11-04
Filing date: 1988-11-04
Publication date: 1989-07-12
Anticipated expiration: 2008-11-04
Also published as: ATA291387A; GB2211910B; AT401413B; DE3836478A1; GB8825841D0

Description

2-211910 CERIN WHEM This invention relates to a chain wheel for round

steel chains, in which upright chain links each lie between the flanks of a double tooth and which the chain links which lie flat (referred to from now on as "lying chain links") each extend between adjacent teeth.

A chain wheel of this type is disclosed in AT-PS 37 679. Central radial tapped bores are provided on the periphery of a wheel bodyr and these bores serve to receive foot parts of double teeth constructed as threaded bolts. On opposite sides of each radial bore there are axial bores for a threaded screw with a nut. The wheel body is divided into two parts by a slit at its periphery, in the region of the radial threaded bores. The double teeth can be screwed into the radial threaded bores and then secured by tightening the axial threaded screws.

Although it is obviously possible to alter the radial positions of the double teethr either individually or as a whole, and to exchange the teeth, the known chain wheel is inevitably expensive to manufacturey because of its type of construction. Adjustment of the double teeth is only possible in steps, corresponding to half revolutions of the threaded bolt foot. Since a large part of this threaded bolt is exposed. its thread can be soiled or damaged, whereby removal is made more difficult. It is also a disadvantage that the large forces applied to the double teeth are transmitted by way of a screw thread to the chain wheel body, since twisting of the teeth with corresponding damage is possible.

Removal of the teeth not only requires a lot of time. but also the use of a special gauge for adjusting the radial position of the double teeth.

A method has also become well know with chain wheelsp the teeth of which engage on the upright chain links. of mounting teeth on the periphery of the wheel body in an exchangeable manner (AT-PS 346 656). Such chain wheels can be used only with chains having longer link spacing since between two adjoining upright chain links a certain minimum tooth strength must be provided and since carriers for conveying elements, e.g. scrapers, are secured in the clear space between the upright chain links. Chains with longer link spacing are, however, bent more acutely when turning around drive wheels or guide wheels, which leads to great wear of the links in the region of their joints.

According to the present invention there is provided a chain wheel for round steel chains, in which upright chain links each lie between flanks of a double tooth and in which lying chain links engage supporting surfaces of the flanks, each double tooth having a foot which is accommodated in a respective recess at the periphery of a wheel body and is removably secured against a surface of the recess by a screwthreaded fastener.

An embodiment in accordance with the present invention provides a chain wheel which enables simple exchange and adjustment of the teeth, with an uncomplicated and cost-effective construction, without impairing the secure fixing of the teeth to the wheel body.

For a better understanding of the present invention. and to show how it may be carried into effectr reference will now be made, by way of example, to the accompanying drawings. in which:

Figure 1 is a partially sectioned axial view of a first embodiment of a chain wheel; Figure 2 is a top view of part of the wheel of Figure 1; Figure 3 is a section taken on the line III-III in Figure 1; Figure 4 is a section taken on the line IV-III in Figure 1; Figure 5 corresponds to Figure 1 but shows a 5 second embodiment of a chain wheel; Figure 6 is a top view of part of the wheel of Figure 5; Figure 7 is a section taken on the line VII-VII in Figure 5; Figure 8 is a section taken on the line VIII-M in Figure 5; Figure 9 corresponds to Figure 1 but shows a third embodiment of a chain wheel; Figure 10 is a top view of part of the wheel of Figure 9; Figure 11 is a section taken on the line X1-XI in Figure 9; Figure 12 corresponds to Figure 1 but shows a fourth embodiment of a chain wheel; Figure 13 is a top view of part of the wheel of Figure 12; Figure 14 is a section taken on the line XIV-XIV in Figure 12; and Figure 15 is a section taken on the line XV-XIV in Figure 12.

The chain wheel shown in Figures 1 to 4 has a wheel body 1 which, for example, is made from cast steel or steel plate and can be mounted on a drive and bearing shaft. not shown, at a hub 2.

At regular angular intervals. in the present case 360p supporting grooves 3 are formed in the periphery of the wheel body 1, which run continuously and parallel to the axis. An axial continuous recess 4 (i.e. extending right across the wheel body 1) is formed in the wheel body 1 correponding to each supporting groove 3. Each recess 4 is situated radially inwards of the corresponding groove 3. and from the base of each groove 3 there extend into the recess 4 two parallel bores 5 which are axially spaced apart from each other. A central peripheral channel 6 5 of the wheel body 1 has a depth which, in the radial directionp is larger than the depth of the supporting grooves 3. This is best seen in Figure 1 where the base of the channel 6 can be seen as a dashed line.

A one-piece double tooth 7 can be inserted into each of the supporting grooves 3. Each tooth 7 has two flanks 8, a foot 9, and a rib 10 projecting from the foot 9. As is clear from the Figures, each double tooth 7 stands with its foot 9 in a supporting groove 31 with the rib 10 received in the peripheral channel 6.

is Each flank 8 possesses two complimentary faces 11, at opposite ends from each other in the peripheral direction# and each flank face 11 is merged by a' supporting shoulder 12 (which. when viewed in the axial direction, is convexly curved) into the foot 9.

Between the faces 11 of each flank 8 there extends a radial bore 13 which, when the teethare inserted in the wheel body 1. is aligned with a bore 5. so that the double tooth 7 can be secured to the wheel body 1 by means of two bolts 14 the inner ends of which project into the recesses 4, where they receive locking washers 16 and nuts 14.

A round steel chain 17, passing around the chain wheel, lies such that each upright link 18 is located between both flanks 8 of a double tooth 7 and such that the flanks 8 engage with their faces 11 on outer surfaces of the lying chain links 19. The lying links 19 lie on this occasion on the supporting shoulders 12 of the flanks 8. The lower side of each upright chain link 18 rests on a bearing surface 20 in which a recess 21 is provided for receiving the weld bulge of the link 18. The recess 21 prevents the weld bulge from leading to damage or premature wear of the bearing surface 20.

The exchangeable double teeth 7 cany for exampley be made of alloyed and hardened steel and, for this reason, have a long life. If nevertheless the teeth andlor the chain wear significantlyr the local circular diameter can be increased by shims 22 laid between a double tooth 7 and the wheel body 1 (Figure 3). This shimming avoids the need to replace the whole chain wheel or its teeth and can be carried out without removing the chain. by operating on those teeth, which do not engage the chain.

In the description of the second embodiment represented in Figures 5 to 8 the same reference numbers are used as before, where appropriate. The second embodiment possesses double teeth 23 which are similar to those of the first embodiments. but are divided along a plane of symmetry 'e' perpendicular to the wheel axis 'a', i.e. they are made up from two complementary halves. These halves are joined together by means of two bolts 24 and nuts 25, which run axially through bores 26 in the foot 9 of the double tooth 23. As shown, the heads of the bolts 24 and the nuts 25 of the double tooth 23 are counter sunk into recesses 27 in the foot 9. so that they do not protrude and cannot be damaged. The heads of the bolts 24 and of the bolts 14 have hexagonal recess heads to allow counter sunk fixing of this kind. The recesses 27 for the nuts 25 are. as seen in Figure 5. constructed in such a way that the nuts 25 cannot rotate, easing assembly.

The two-piece construction fo the double teeth 23 offers the advantage that. on the one hand$ the manufacture of the teeth is simpler and cheaper and that. on the other hand. only individual teeth halves need be exchanged when damaged. Also with this embodiment the use of shims as described above is possible and advantageous.

A third embodiment of the invention represented in Figures 9 to 11 shows double teeth 28. which each comprise two separate teeth 29 constituting tooth flanks of the double.tooth. The teeth 29 have feet 30 'which are located in recesses 31 situated opposite each other on the peripheral region of the wheel body 1. These recesses 31 have. when viewed in the axial direction. the same rectangular form as the grooves 3 of Figures 1 and 9, but do not extend right through the wheel body 1 like the grooves 3. A rib 32 is interposed between the recesses 31. projecting from the wheel body. The separate teeth 29 of each double tooth 28 are positioned opposite each other on each side of the rib 32 and are fixed by two bolts 33 and nuts 34.

These bolts 33 run axially through bores 35 into the feet 30 of the teeth 29 and through the rib 32 of the wheel body 1. The nuts 34 could be counter sunk into the feet 30 as described for the nuts 25 in Figure 5. With this embodiments the local circular diameter cannot be enlarged by using shims but the construction is particularly simple and cost-effective.

The fourth embodiment represented in Figures 12 to 15 is similar to the first embodiment represented in Figures 1 to 4. One-piece double teeth 36 are used, the feet 9 of which are located axially in continuous, supporting grooves 3 in the wheel body 1. However. the fixing of each double tooth 36 is achieved by a single mounting bolt 37r which passes through radial bores 39 or 40 in the foot 9 and wheel body 1, extending Centrally between tooth flanks 38 and is tensioned with a nut 41 within the recesses 4. Two flanges 42 projecting downwards from each foot 9 embrace the periphery of the wheel body 1. The head of the bolt 37 has a hexagonal recess and can be countersunk so far into the foot 9 of the double tooth 23, that a recess 21 to allow clearance for the welding seam of the standing chain link 18 remains.

In the embodiments shown the supporting shoulder 12 has a convexly curved surfacei such that with the differing diameters of the chain wheel a defined bearing surface for the lying chain link 19 is always created. reducing wear in the chain links. The above convex curvature is. therefore. particularly advantageous if similarly constructed teeth are used with chain wheels of a greatly different diameter.

Claims

1. A chain wheel for round steel chains, in which upright chain links each lie between flanks of a double tooth and in which lying chain links engage supporting surfaces of the flanks, eachdouble tooth having a foot which is accommodated in a respective recess at the periphery of a wheel body and is removably secured against a surface of the recess by a screwthreaded fastener.

2. A chain wheel as claimed in claim 1. in which each recess is a supporting groove which extends continuously and parallel to the axis of the wheel.

3. A chin wheel as claimed in claim 2, in which a central peripheral channel is provided. in the wheel body, the depth of which, in the radial direction, is greater than the depth of the supporting grooves,.and in which each double tooth has a rib projecting downwards from its foot, the rib lying in the peripheral channel. 20

4. A chain wheel as claimed in any one of claims 1 to 3, in which the foot of each tooth is provided with flanges projecting radially inwards to embrace the wheel body.

5. A chain wheel as claimed in any one of claims 1 to 4, in which each double tooth is divided along a plane of symmetry perpendicular to the wheel axis.

6. A chain wheel as claimed in any one of claims 1 to 5, in which each tooth is secured to the wheel body by two bolts which extends through radial bores in the tooth flanks, between the supporting surfaces.

7. A chain wheel as claimed in any one of claims 1 to 5, in which each tooth is secured to the wheel body by a bolt which extends through radial bores situated centrally between the tooth flanks in the foot and in the wheel body.

8. A chain wheel as claimed in claim 6 or 7. in -g- which corresponding to each double tooth fitted to the wheel body there is a continuous, axially aligned recess accommodating nuts on the radially extending bolts. 5

9. A chain wheel as claimed in claim 5. in which both halves of each double tooth are fitted together by means of two bolts which extend axially through bores in the foot of the double tooth.

10. A chain wheel as claimed in any one of claims 1 to 9. in which a shim is provided between the foot of each double tooth and the base of the supporting recess, to enlarge the local circular diameter.

11. A chain wheel as claimed in any one of claims 1 to 10, in which each double tooth has a bearing.

surface for the lower side of an upright chain link accommodated between its tooth flanks.

12. A chain wheel as claimed in claim 11, in which the bearing surface has a recess for accommodating a weld bulge on an upright chain link. 20

13. A chain wheel as claimed in claim 1, in which each double tooth comprises two separate teeth having feet accommodated in recesses disposed opposite to each other at the peripheral region of the wheel body, the feet of the teeth being secured against a rib of the wheel body situated between the recesses by a bolt extending axially through bores in the feet and in the rib.

14. A chain wheel as claimed in any one of claims 1 to 13, in which the supporting surfaces for the lying chain links, seen in the axial direction, have a convex curvature.

15. A chain wheel substantially as described herein with reference to, and as shown in, Figures 1 to 4, Figures 5 to 8, Figures 9 to 11 or Figures 12 to 15 of the accompanying drawings.

Published 1989 atThe Patent Office, State House. 66171 High Holborn. London WC1R4TP. Further copies maybe obtainedfrom The Patent Office.

------- ---- W k Jni.rjr rurmer copies maybe obtained from The P.t- -