EP0242342A1

EP0242342A1 - Fan

Info

Publication number: EP0242342A1
Application number: EP87850096A
Authority: EP
Inventors: John Adolf Mannerblad
Original assignee: PAX ELECTRO PRODUCTS AB
Current assignee: PAX ELECTRO PRODUCTS AB
Priority date: 1986-04-17
Filing date: 1987-03-24
Publication date: 1987-10-21
Also published as: FI871690A0; NO871522L; DK193087D0; SE8601748D0; NO871522D0; FI871690A; DK193087A; SE8601748L

Abstract

A fan for steady mounting on a wall or the like is divided in two independent constructional units (10, 20) which by means of a quick coupling of the bayonettype (21a', 21 b', 31a, 31b) and a couple of electrical terminal means (14, 24) may be readily assembled and disassembled, whereby dismounting for repair or exchange purposes is facilitated.

Description

The invention refers to a fan adapted for mounting on a support means such as a wall, and which comprises an electric motor fed by a supply main and carrying on its output shaft a fan impeller. For'such maintenance and repair work which can not be done on the spot, the fan must be taken down from the wall and transported to a workshop. This was up now rather intricate , because it was necessary, after switching off the feeding current, to disconnect the fan from the supply main and to screw loose the entire fan housing from the wall. The uninsulated ends of the supply main, which thus became freely accessible, had to be temporarily insulated, or the respective main section had to be cut off during the whole duration of the repair work.
In order to facilitate said repair and maintenance work by simplifying the removal of the moving parts of the fan (i.e. the parts which most.often need maintenance and reapir), it has been already proposed in DE-A-1 778 585 to divide such a fan into two parts, viz. a first part provided with means for attachment to the wall and with means for connecting an electrical supply main to and a second part, disengageably connected therewith, and carrying the motor and the fan impeller, both parts being provided with co-operating means for .the electric connection of one with another when the parts are mechanically joined one to another. In one embodiment, the first part is defined by a square block with a circular central opening, and the other part is defined by a square frame, the outer periphery of which corresponds to the outer periphery of the block, and in the square opening of said frame is a cylindrical motor housing suspended with the aid of a U-shaped yoke bridging the.whole square opening.
The frame is attached to the block by means of four screw connections defined by screws located in the corners of the block arid which pass through corresponding holes provided in the four corners of the frame. The electrical contact is obtained by means of two contact tongues protruding from the frame and which are introduced into corresponding contact appertures in the block.
Screw connections demand generally a tool, such as a screw driver or a span, to be released as well as tightened. It is an object of the present invention to provide a fan of the aforesaid kind, i.e. one which is divided into two parts, in which the two parts can be disassembled and reassembled in a more simple way because, in principle, no screw connection at all is needed, or, if even a locking function is desired, only one such connection is necessitated.
The invention is characterised by features which are evident from the accompanying claims, and it will now be explained more in detail with the aid of the attached diagrammatic drawings which refer to an exemplary embodiment and in which

Fig. 1 is a perspective view of a fan according to the invention in disassembled state and with the cover removed, and
Fig. 2 is a perspective view on a smaller scale of the fan of Fig. 1 in assembled state, and with the cover put on.

According to Fig. 1 the fan according to the present invention comprises two.quite independent construction parts, viz. an attachment unit 10 and a motor housing unit 20. The attachment unit 10 comprises a bottom part 11 defined by a planar plate 11 which is adapted to be with its rear side or face, i.e. the one which is turned away and not visible in the drawing, applied against a support, e.g. a wall, and affixed thereto by means of mounting screws, not shown, which pass through smooth (i.e. not threaded) openings 10' and are screwed in into e.g. plugs provided in bores in the respective wall.
In the bottom part 11 there is an opening 12 provided which has an inner width or inner diameter D and a circular periphery 12a. The attachment unit 10 is.located at such a place on the wall (not shown), where the orifice of an air duct (having a diameter at least so.large as the opening 12) will be centered relative to the said opening.
The motor housing unit 20 has the shape of a cylinder or a pot with an outer diameter d which is smaller than the diameter D of the opening 12. In the motor housing unit 20 is an electrical motor (not shown) fixed, to the output shaft of which,not shown, but having a centre line C, a fan impeller 25 is attached.
Three carrier arms 21a, 21b and 21c, arranged at selected spacement one from another, in the example shown at 135° and (between the arms 21a and 21b) 90°, project radially from the periphery 22a of the bottom part 22 of the motor housing unit 20. The free ends of the carrier arms are shaped into small plates 21a', 21b' and 21c' which are considerably thinner than the remaining parts 21a", 21b" and 21c" of the carrier arms. Said parts 21a", 21b" and 21c" are actually dimensioned so that the transitional edges, such as 21a'" or 21c"', between them and the parts 21a', 21b' lie on a fictious circle with the diameter D. Thus, upon assembly of the units 10 and 20, the parts 21a", 21b" and 21c" penetrate into the opening 12, and the parts 21a', 21b', 21c' come to rest on that side or face 11' of the bottom part 11, which in the drawing is the forward one, turned toward the observer. In this way an annular air passage E is obtained between the peripheries 12a and 22a upon assembly of the units 10 and 20, as is.shown with a broken line in Fig. 1. The part 21c" is, in contradistinction to the parts 21a" and 21b", provided with a smooth hole 26.
The parts 21a', 21b' and 21c' embody fixing means which together with co-operating fixing means on the attachment unit 10 define a readily assemblable and readily dismountable fixing device for fastening the.motor housing unit 20 to the attachment unit 10. The fixing means on the attachment unit are located along the periphery 12a and are, in the example shown, embodied by the two hook means 31a, 31b and one threaded hole 31c.
Upon assembly, the motor housing unit 20 is introduced into the opening 12 in the sense of arrow F, and the parts 21a' and 21b' are by a small rotation about the axis C in the sense of arrow G brought under the hooks 31a and 31b until they abut. Hole 26 in the part 21c' will then be aligned with the threaded hole 31c and a locking screw 26' may be screwed in. A guiding wall 31b', adjacent the hook means 31, contributes to unambigously define the position of the motor housing unit 20 relative the attachment unit 10.
The fixing device consists thus of the two pairs of elements 21a', 31a and 21b', 31b respectively which embody a bayonet joint, and of the elements 21c", 26, 26', 31c which define a combined fixing and locking means. The purpose of the locking function is to make sure that the motor housing unit 20 .cannot get loose, e.g. due vibrations etc.
Between the motor housing unit 20; which by means of the parts 21a", 21b" and.21c" is centered in the opening 12, and the periphery 12a of this opening,the annular air passage E, already meantioned, is obtained. From the turned away rear face of the bottom part 11' projects a cylindrical casing 13 which begins at the periphery 12a and has the same inner diameter D as this periphery. Thus an air duct is added to the air passage E in which duct the fan impeller 25 is located and operates. The attachment unit 11 is with this casing 13 pushed into an admission or discharge duct which has been prepared in the respective wall and which communicates with a ventilating shaft or the like.
A peripheric.edge 11a, defining a sort of frame along the whole bottom part 11, projects from the forward face 11' of the bottom part 11. Two minor inner spaces A and B are detached by two inner separating walls 11b, 11c which have the same height as the peripheric edge 11a. A terminal block 14 is mounted in the space A, and the supply main 15 is connected to the block via a stress-reliever 14a.
The motor housing unit 20 is provided with a connecting cable 27 which inside the motor housing unit is connected to the fan's electric motor and which at its other, free end carries a contact means 24 with two contact pins which may be introduced into corresponding contact bushes in the terminal block 14 and possibly fastened by screws (a third bushing is provided in the terminal block 14 for a possible time regulator , in which case the.corresponding means may be accommodated in space.B). Lips 16a are provided to fix the various cable means.
It will be appreciated that, when the moving parts of the fan shall be removed, it is more simple only to loosen the screw 26', to rotate the motor housing unit 20 against the sense of arrow G,_.and to disconnect the connector couple 14/24, than to screw off the whole fan from the wall and to disconnect the main supply from the terminals of the electric motor. Moreover, the respective section of the power network does not need to be disconnected (or at least not during all the time the motor housing unit is removed), because there is no risk of short-circuiting in the terminal block 14; in this respect the situation may be compared to a ceiling light fitting being removed without the necessity to make the respective connecting means currentless for this reason. Possibly, a replacement motor housing unit may be readily inserted in the attachment unit for the duration of the repair work.
In Fig.-2 there is shown a cover 16 by which the whole attachment unit 10 may be covered, primarily out of aesthetic reasons. The cover 16 may be readily mounted and dismounted (much in the same way as the cover of the batteries compartment in certain domestic electronic appliances) with the aid of screws (not shown) which are screwed in into holes 10".
In order to obtain a sufficient spacement from the bottom plate 11', the cover is adapted, e.g. by means of an own peripheric edge, which may be set on the peripheric edge 11a of the attachment unit, to lie at such a distance from the bottom part 11' that elements such as 14, 31a, 31b etc., mounted on the bottom part, may be accommodated in the interspace.
Several alternatives of the embodiment which has been described as an example are possible within the scope of the invention, e.g. the following modifications:

- the attachment unit may have another shape than rectangular;
- the motor housing unit may have another shape than cylindrical;
- the opening 12 and the cover 13 may have another cross- section than circular;
- the terminal block 14 needs not to be affixed to the attachment unit 10;
- the locking device 21", 26, 26', 31c may be of some other kind, e.g. quite separate-from the fixing function, or it may be totally dispensed off; or
- an as well lesser as greater number of carrier arms than three may be used.

Claims

1. Fan for steady mounting on a support means such as a wall or the like and comprising, on the one hand, an attachment unit (10) which is adapted for fastening to the support means and is provided with an opening corresponding to an air duct in the support means and with a terminal means (14) for an electric main supply (15), and, on the other hand, a motor housing unit (20) having an outer dimension (d) which is lesser than the clearance (D) of said opening, in which unit (20) an electric motor is accommodated on the outgoing shaft of which a fan impeller (25) is mounted, both said units being provided with co-operating, fixing means for releasably fastening the motor housing unit to the attachment unit, and the motor housing unit being provided with a connector means (24, 27) for connecting the electric motor to the terminal means of the attachment unit,p characterised by the fact that carrier arms (21a, 21b, 21c) radially project from the motor housing unit and that at least some. of the fixing means define co-operating parts (21a, 21b,31a, 31b) of.a bayonet joint which, on the one hand, are located at the free ends of the carrier arms, and, on the other hand, along the periphery (12a) of said opening, and that the contactor means is of a kind allowing a relative rotation between the two said units, whereby the motor housing unit may be mounted to and dismounted from the attachment unit by a short rotary movement.

2. The fan of claim 1, characterised by the parts of the bayonet coupling joint being embodied by at least two hook elements (31a, 31b) located at a selected spacement along the periphery of the opening, and by engagement means, defined e.g. by small plates (21a', 21b') located at the free ends of the carrier arms, and which may be introduced into the hook elements.

3. A fan according to claim 1 or 2, characterised by a locking means (26, 26', 31c) securing the motor housing unit against disengagement.

4. The fan of claim 3, characterised by the locking means being.located on the.free end of a carrier arm (21c) and defining at the same time an additional fixing means.

5. The fan of claim 4, characterised by the locking means being embodied by a smooth hole (26) arranged at the free end of a carrier arm, a threaded hole (31c) located at the periphery of the opening, and a locking screw (26') which may pass through the smooth hole and be screwed-in into the threaded hole.

6. A fan according to anyone of the preceding claims, characterised by the carrier arms having, adjacent their free ends, parts (21a', 21b', 21c') which are introducible into the opening in the attachment part, and the edges (21a"' , 32a"') of which, turned to the free ends, lie on a line co-inciding with the periphery of said opening.

7. A fan according to anyone of the preceding claims, characterised by the motor housing unit having, in per se known manner, a cylindrical shape, and the periphery of the opening in the attachment unit being circular.

8. A fan according to anyone of the preceding claims, characterised by the attachment unit comprising a bottom part (11) with said opening and a peripheric edge (11a) which projects from the bottom part on the side where the fixing means are provided.

9. A fan according to anyone of the preceding claims, characterised by the fact that from the attachment unit projects, on the reverse side than where the fixing means are provided, a cover (13) which is contiguous to the opening and defines a limitation of said air duct.

10. A fan according to anyone of the preceding claims, characterised by the contactor means of the motor housing unit comprising an electrical flexible cord (27) on the free end of which a contact means (24) is mounted which can be connected to the terminal means of the attachment unit.