GB2041102A

GB2041102A - Axial flow fans

Info

Publication number: GB2041102A
Application number: GB7943853A
Authority: GB
Original assignee: PETZ ELEKTRO WAERME TECHN
Current assignee: PETZ ELEKTRO WAERME TECHN
Priority date: 1978-12-22
Filing date: 1979-12-20
Publication date: 1980-09-03
Also published as: ES487188A1; GR66440B; CH638593A5; DE2855478A1; IT7951145A0; DE2855478C2; GB2041102B

Abstract

A fan wheel having fan blades and a hub disc 2 has a central opening 3 receiving a hub body 6. The hub body 6 is supported on the hub disc 2 by a shoulder 7 and retained by retaining fingers 8 having enlargements 9 locatable in apertures 4 provided in the hub disc and arranged on a circular line concentric with the central opening 3. Out-turned lugs 5 are bent back into the plane of the hub disc 2 to lock the fingers 8 in place. <IMAGE>

Description

SPECIFICATION A fan wheel for axial blowers The present invention relates to a fan wheel for axial blowers having fan blades located on a hub.

It is known, in fan wheels of this kind, to secure the fan blades by riveting them to a hub body. The hub body in known fan wheels is formed substantially as a cylindrical solid body which accommodates, in a central opening, the driving shaft and is clamped thereto securely a screw screwed into a tapped bore.

Apart from the fact that this connection requires a considerable manufacturing effort, the use of a screw to secure the fan wheel is also cumbersome and requires maintaining dimensional tolerances for the bore and the driving shaft.

It is an object of the invention to permit the fan blades and hub body to be connected simply and swiftly and preferably to simplify the securing of the hub body to the driving shaft.

According to the invention there is provided a fan wheel for axial blowers comprising fan blades and a substantially flat hub portion, which hub portion receives a hub body in a central opening thereof, and supported at one end against the hub portion, the hub body has hook-shaped retaining fingers which pass through offset apertures arranged around the central opening and engage behind the edge surfaces thereof and notches are provided bent into the apertures to support the retaining fingers without distortion.

The recesses and the retaining fingers are preferably formed on a circular line concentric to the central opening, whilst at least two fan blades and the hub portion may form an integral moulding of a metal or plastically deformable material. To connect the fan blades with the hub body, moulded from an insulating material, now requires a simple plug connection, whereby the surfaces of the central opening centre the hub body and the retaining fingers providing a non-displaceable support. The notches for simplified insertion of the retaining fingers for the duration of the plug connection are bent out of the hub portions and may subsequently bend back.

Enlargements possibly provided on the retaining fingers, if necessary, together with the edge surfaces of the apertures ensure automatic bending in of the retaining fingers during the plug connection. The hub body also ensures an insulated retention of the fan blades on the driving shaft.

Finally, provision is also made for the hub body to have a central hub sleeve slotted over part of its length, the sleeve sections of which, extend adjacent to the slots, is enclosed by a spring ring and by means of these adapted to be bent inwardly towards one another. When sliding on the fan wheel of the driving shaft of a motor the sleeve sections are bent outwards, which subsequently, by permanent pressure against the driving shaft, secures the fan wheel.

The present invention will be described further, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a side view, partly in section, of a fan wheel; Figure 2 is a fan wheel in plan view; and Figure 3 is a fragment of a fan wheel on an enlarged scale.

In Figs. 1 and 2 two diametric fan blades 1 are provided which, with a hub portion 2, form an integral moulding, e.g. a sheet metal moulding. The hub portion 2 is substantially flat and provided with a central aperture 3 which is defined by a bentover collar 3'.

Concentric with the central opening 3 a a plurality of openings 4 are cut offset into the hub portion 2 into which partly project notches 5. A hub body 6 made of a plastically deformable material is provided, which, without clearance, engages in the central aperture 3 and is supported against one side of the hub portion 2 by a shoulder 7. On the hub body 6 offset hook-shaped retaining fingers 8 are formed which, in the attached position, pass through the openings 4 and, by means of enlargements 9, engage behind the edge surfaces 4' of the openings 4 located on the other side of the hub portion 2.The enlargements 9 have bevel surfaces 9', which, during attachment, by butting against the edge surfaces of the openings 4 are subjected to the component of the attachment force, acting at right angles to the direction of atachment, which bends the retaining fingers 8 inwardly towards one another and upon the enlargements 9 passing the edge surfaces, the fingers 8 automatically return outwardly-to provide a snap fitting. During attachment, the notches 5, as shown in Fig. 3 by chain-dotted lines, may at first be bent over diagonally and the retaining fingers 8 secured by subsequent bending into the openings 4.

The hub body 6 moreover is provided with a central hub sleeve 10 which, over part of its length, has sleeve sections 10' with slots 11.

A spring ring 1 2 is drawn onto the sleeve sections 10' which spring 1 2 bends the sleeve sections 10' inwards towards each other. During the sliding of the fan wheel onto the driving shaft 1 3 of an electric motor 14, the sleeve sections 10', by butting against the end edge face of the driving shaft 13, initially against the pre-tension of the ring spring 12, or by the ring spring 1 2 and material stresses, are automatically bent outwards and then retained pressed against the surface of the driving shaft 13.

The hub body 6 provides the advantage of the insulated arrangement of metal blades 1 on driving shafts 1 3.

Claims

1. A fan wheel for axial blowers comprising fan blades and a substantially flat hub portion, which hub portion receives a hub body in a central opening thereof; and supported at one end against the hub portion, the hub body has hook-shaped retaining fingers which pass through offset apertures arranged around the central opening and engage behind the edge surfaces thereof and notches are provided bent into the apertures to support the retaining fingers without distortion.

2. A fan wheel according to claim 1, in which the apertures and the retaining fingers are formed on a circular line concentric to the central opening.

3. A fan wheel according to any preceding claim, in which the arrangement of at least two fan blades which with the hub portion form an integral shaped part made of a metallic or plastically deformable material.

4. A fan wheel according to claim 1, in which the hub body is moulded from an insulating material.

5. A fan wheel according to any preceding claim, in which the notches are adapted to be bent out of the plane of the hub portion and also to be bent back into it.

6. A fan wheel according to any preceding claim, in which the retaining fingers are provided with enlargements with bevelled surfaces.

7. A fan wheel substantially as herein described with reference to and as illustrated in the accompanying drawings.