A CHAIN WHEEL FOR CHAIN CONVEYOR BELTS

Abstract: A chain wheel for conveyor installations with chain conveyor belts, and which chain wheel is mounted on the drive shaft (5) of the driving device for the conveyor belt. The chain wheel is designed in such a manner that it can be easily repaired and altered as to number of teeth, design of hub and number of tooth rims. It incorporates as a basic unit a pair of hub portions (1,2) detachably connected against each other, between which, as a separate unit, is clamped a tooth rim (3) comprising at least two sections (3a,3b).

Description: The present invention refers to a chain wheel according to the first part of claim 1. For example in US-A-4043214 a chain wheel having these features disclosed. In such conveyor installations are used moulded or milled chain wheels as power transfer means between driving motor and chain. Such chain wheels are simple and functional but it occurs that hub or tooth rim are damaged under operation, which means that the chain wheel has to be replaced. This is often difficult and commonly means substantial shutdowns. The purpose of the present invention is to provide a chain wheel of the type mentioned above, which is designed in such a manner that it may be altered in simple manner as to number of teeth, design of hub and number of tooth rims. It furthermore shall be easy to repair, whereby shutdowns in connection with repairs can be reduced. This has been solved in accordance with the invention through the features in the characterising part of claim 1. The invention hereinafter will be further described with reference to an embodiment shown in the accopmanying drawing. Fig. 1 is a front view of a chain wheel according to the invention. Fig. 2 is a section along line II-II in Fig. 1. Fig. 3 shows in bigger scale an exploded view of some of the components forming part of the chain wheel according to Fig. 2. The chain wheel according to the invention is built from standard parts, which may be combined in several manners in order to provide different types of chain wheels. A standard wheel having one tooth rim is constructed from two hub portions, an outer and an inner hub portion 1 and 2, a tooth rim 3 split into two sections 3a and 3b and a reinforcing disc 4. The hub portions and the tooth rim may be of plastic material, e.g. nylon, whereas the reinforcing disc is made of steel. The reinforcing disc 4 is mounted on the drive shaft 5 and is in engagement with this via a key groove 6. The hub portions 1 and 2, the tooth rim 3a and 3b and the reinforcing disc 4 are clamped against each other by means of bolts 7. The tooth rim sections 3a and 3b are arrested in accurate position by means of trapezoidal profiles 8, 9 formed in the hub portions 1 and 2 and in the tooth sections 3a and 3b, resp. The trapezoidal profiles 8 serve, beside as guides, also as friction surfaces between hub and tooth rim, as this is not fixedly connected to the drive shaft 5 but has the driving power thereof transferred via the reinforcing disc 4 and the hub portions 1 and 2. These thereby shall be clamped together with such big force that the friction resistance between the hub portions 1 and 2 and the tooth rim 3 exceeds the torsional resistance from the drive shaft 5. By varying the clamping force it is thereby possible to settle a maximum torsional moment that may be transferred to the tooth rim 3 and the system thereby functions as a safety coupling against overload of the conveyor chain. Exchange of the tooth rim, which can either be necessitated by it being damaged or by a desire to alter the number of teeth, is effected by untightening the bolts 7 and moving apart the hub portions 1 and 2, whereupon the tooth rim sections 3a and 3b can be removed from the hub and be replaced for new ones. If it is necessary only to exchange one of the tooth rim sections this is of course also possible. The bolts 7 are thereupon clamped with a force corresponding to the frictional resistance which is desired to obtain. Exchange of tooth rim thus can be effected without the hub having to be dismounted from the drive shaft 5, which means a substantial time saving and lower costs for spare parts. The chain wheel can be easily enlarged with more tooth rims, e.g. at an increased load on the conveyor chain. A double chain wheel thus is built from two outer hub portions 1, two inner hub portions 2 and two tooth rims 3. A treble chain wheel in the corresponding manner is built from two outer hub portions 1, four inner hub portions 2 and three tooth rims 3.

Claims: 1. A chain wheel for conveyor installations with chain conveyor belts, which chain wheel is mounted on the drive shaft (5) of the driving device for the conveyor belt, whereby a basic unit incorporates a pair of hub portions (1, 2) detachably connected against each other, between which, as a separate unit, is clamped a tooth rim (3) comprising at least two sections (3a, 3b), characterized therein, that the hub portions (1, 2) are mounted on the drive shaft (5) via a reinforcing disc (4) clamped between the hub portions inside the tooth rim (3), whereby the torsional moment from the drive shaft (5) is transferred to the tooth rim (3) via the reinforcing disc (4) and the hub portions (1, 2). 2. A chain wheel as claimed in claim 1, characterized therein, that the contact surfaces between the hub portions (1, 2) and the tooth rim sections (3a, 3b) are provided with profiles (8) for guiding purposes and also for increasing the frictional resistance. 3. A chain wheel as claimed in claim 1 or 2, characterized therein, that the clamping force for the hub portions (1, 2) is adjustable for determining a maximum torsional moment that can be transferred from the drive shaft (5) to the tooth rim (3) via the reinforcing disc (4) and the hub portions (1, 2), thus that when exceeding said maximum torsional moment the friction resistance between the hub portions (1, 2) and the tooth rim (3) is lower than the torsional moment from the drive shaft (5). 4. A chain wheel as claimed in any of claims 1-3, characterized therein, that the hub portions (1, 2) and the tooth rim (3) are made in plastic material whereas the reinforcing disc (4) is of metallic material, e.g. steel. 5. A chain wheel as claimed in one or more of the preceeding claims, characterized therein, that it is designed as a modular system which can be enlarged with several basic units incorporating tooth rims (3) with associated hub portions (1, 2).

Inventors: DRAEBEL, JORGEN
Applicants: SKF SPECIALTY PRODUCTS AB
Application year: 1988
Main classification: F16H55
IPC codes: F16D7, B65G23, F16H55