EP0688633A1

EP0688633A1 - Shot blast wheel

Info

Publication number: EP0688633A1
Application number: EP94304575A
Authority: EP
Inventors: Jan Hendrik Hofmeyr Van Huyssteen
Original assignee: SPEEDLOCK SHOTBLAST SYSTEMS CC
Current assignee: SPEEDLOCK SHOTBLAST SYSTEMS CC
Priority date: 1994-06-23
Filing date: 1994-06-23
Publication date: 1995-12-27

Abstract

The invention provides a shot blast wheel assembly comprising a disc member (11) adapted to be rotatably mounted, and having a plurality of generally rectangularly disposed blade members (12) mounted on a front surface (11a) thereof, the disc member (11) defining a plurality of radially disposed groove formations (11c) on the front surface (11a) thereof adapted to receive corresponding elongated tongue formations (12a) defined on the lower longitudinal surface of the blade members (12), and inter-acting engagement formations towards the outer zone of the groove, and in a corresponding position on the lower surface of the blade (12b) respectively whereby radially outwardly directed movement of the blade is prevented as well as movement away from the surface (11a) of the disc, and locking means (13,14) for urging the engagement formations into engagement.

Description

BACKGROUND TO THE INVENTION

THIS invention relates to a shot blast wheel of the type wherein shot material is introduced to a rotating wheel having a plurality of radially disposed blades mounted thereon, the blades acting to throw the shot radially outwardly.

OBJECT OF INVENTION

It is an object of the present invention to provide a novel shot blast wheel which will have advantages over conventional shot blast wheels in respect of manufacture and assembly, thus providing a less costly product, and one whereof maintenance and replacement of wear parts is facilitated.

SUMMARY OF INVENTION

According to the invention a shot blast wheel assembly comprises a disc member adapted to be rotatably mounted, and having a plurality of generally rectangularly disposed blade members mounted on a front surface thereof, the disc member defining a plurality of radially disposed groove formations on the front surface thereof adapted to receive corresponding elongated tongue formations defined on the lower longitudinal surface of the blade members, and inter-acting engagement formations at or towards the outer end of the groove, and in a corresponding position on the lower surface of the blade respectively whereby radially outwardly directed movement of the blade and movement of the blade away from the surface of the disc, is prevented and locking means for urging the engagement formations into engagement.
Preferably the locking means will act to urge the blade radially outwardly to effect a locking function. With such an arrangement the engagement formations on the blade and wheel will preferably be in the nature of a socket formation in the wheel surface, and a corresponding spigot formation defined by the blade, with the formations being angled radially outwardly. Preferably the socket formation will be angled between 10° and 70° relative to the rotational axis of the disc. Preferably the angle will be in the order of 40°.
Preferably the locking means will be disposed towards a radially inward zone of the blade and in a preferred arrangement will comprise an angled abutment surface adapted to engage a corresponding surface at or towards the inner extremity of the blade to urge the latter radially outwardly direction and in a direction towards the surface of the disc member. Such an angled abutment surface could for example be defined on a flange formation forming part of an impeller of the shot blast wheel. The angle of the abutment surface will preferably be in the order of 30° relative to the rotational axis of the disc member.
Further according to the invention a resilient buffer member is disposed between the abutment surface and the corresponding surface of the blade. Such buffer member could for example be defined by portion of an O-ring or rubber or the like.
The invention also includes separately within its scope a blade member and a disc member for use in the assembly described above.

DETAILED DESCRIPTION OF INVENTION

Other features of the invention will appear from the embodiment described below to exemplify the invention wherein:

Figure 1: is a partially broken away partially exploded perspective view of a shot blast wheel assembly in accordance with the invention;
Figure 2: is a sectioned elevation of the shot blast wheel assembly in Figure 1; and
Figure 3: is an enlargement of portion of Figure 2.

Referring to the drawings a shot blast wheel 10 comprises a circular disc 11 defining a front surface 11a on which a plurality of blade members 12 are mounted in generally radial orientation. In use the disc will be mounted at the end of a drive shaft, not shown, by means of a rearwardly directed boss formation 11b.
The disc 11 defines a plurality of radially disposed groove formations 11c which are adapted to receive corresponding tongue formations 12a defined on the bottom longitudinal surfaces of the blade members 12, each groove formation terminates short of the outer periphery 11d of the disc 11. Towards but inwardly spaced from the outer end of each groove 11c, a socket formation 11e is defined. The socket formation 11e is angled away from the rotational axis of the disc 11 and is directed towards the outer periphery 11d of the disc 11. The angle of the socket 11e can vary according to design criteria, but will preferably be in the order of between 10° and 70°, preferably around 40° relative to the rotational axis of the disc.
The socket formation 11e is adapted to receive a spigot formation 12b defined on the bottom longitudinal zone of the blade 12, with opposed surfaces 11g and 12d of the socket and spigot engaging so that the blade is locked against radial outward movement as well as movement away from the surface 11a of the disc 11. It will be appreciated that the surfaces 11g, 12d, perform a wedging function so that centrifugal force on the blade 12 will cause the blade 12 to wedge tightly against the surface 11d of the disc 11.
In one arrangement in accordance with the invention the lower surface 12c of the tongue formation 12a on the blade 12 will contact the bottom surface 11f of the groove 11c during such wedging action. alternatively, the blade may be provided with longitudinal shoulder formations, not shown, on one or both sides thereof so that these make contact with the surface 11a of the disc 11 during the wedging action described above. It is envisaged that such interrupted shoulder formations will be adapted to reduce wear on the sides of the blade 12 in use.
In order to wedge the spigot 12b securely within the socket 11e, locking means 13 is provided to urge the blade radially outwardly as well as towards the surface 11a of the disc 11, such locking means 13 comprising an angled abutment surface 13a which engages a corresponding surface 12e on the inner zone of the blade 12. In a preferred arrangement as illustrated, the abutment surface 13a will be defined by a flange formation 14a forming part of an impeller 14 which is secured to the disc 11 by means of bolts 15 or the like.
It is a feature of the invention that a resilient buffer 16 will be disposed between the abutment surface 13a and the corresponding surface 12e on the blade 12. Such a resilient buffer 16 is preferably constituted by an O-ring of rubber or synthetic resinous material disposed in a circular groove shown at 11g defined in the upper surface 11a of the disc 11. Preferably the circular groove 11g will be angled inwardly towards the rotational axis of the disc 11 as illustrated.
During assembly of the wheel the blades 12 will thus be placed in position with the tongue formations 12a and spigot formations 12b engaging in the grooves 11c and sockets 11b engaging in the grooves 11c and sockets 11e respectively. The O-rings 16 will then be placed in its groove 11g and thereafter the impeller 14 will be bolted in position thereby to secure all the blades 12 to the wheel 11. It will be appreciated that the resilient nature of the O-rings 16 will ensure that all the blades 12 are engaged by the flange formation 14a of the impeller 14.
Apart from advantages in assembly and disassembly of the wheel, the disc and blades of the invention require relatively few machining operations during manufacture.
Clearly variations in detail of the invention may exist without departing from the principles set out in the consistory clauses. The invention includes within its scope a shot blast wheel assembly, the disc of such wheel, the blade members thereof as well as the impeller, all substantially as disclosed above.

Claims

A shot blast wheel comprising a disc member adapted to be rotatably mounted, and having a plurality of generally radially disposed blade members mounted on a front surface thereof, the disc member defining a plurality of radially disposed groove formations on the front surface thereof adapted to receive corresponding elongated tongue formations defined on the lower longitudinal surface of the blade members, and inter-acting engagement formations towards the outer zone of the groove, and in a corresponding position on the lower surface of the blade respectively whereby radially outwardly directed movement of the blade is prevented as well as movement away from the surface of the disc, and locking means for urging the engagement formations into engagement.
The shot blast wheel assembly according to claim 1 wherein the locking means acts to urge the blade radially outwardly to effect a locking function.
The shot blast wheel assembly according to claim 1 or claim 2 wherein the engagement formation defined by the wheel is in the nature of a socket formation and the engagement formation defined by the blade is in the nature of a mating spigot formation, the engagement formations being angled relative to the plane of the wheel surface.
The shot blast wheel assembly according to claim 3 wherein the spigot and socket formations are angled between 10° and 70° relative to the rotational axis of the disc.
The shot blast wheel assembly according to claim 4 wherein the spigot and socket formations are angled at approximately 40° relative to the rotational axis of the disc.
The shot blast wheel assembly according to any one of claims 1 to 5 wherein locking means is disposed at or towards a radially inner zone of the blade.
The shot blast wheel assembly according to claim 6 wherein the locking means comprises an angled surface adapted to engage a corresponding surface at or towards the inner extremity of the blade to urge the latter radially outwardly towards and in a direction towards the surface of the disc member.
The shot blast wheel assembly according to claim 6 wherein the angled abutment surface is defined by a flange formation forming part of an impeller of the shot blast wheel assembly.
The shot blast wheel assembly according to claim 6 or claim 7 where the angle of the abutment surface and the corresponding surface on the blade are approximately 30° relative to the rotational axis of the disc member.
The shot blast wheel assembly according to any one of claims 6 to 9 wherein a resilient buffer is disposed between the abutment surface and the corresponding surface on the blade.
The shot blast wheel assembly according to claim 10 wherein the buffer member is an O-ring of rubber or other resilient material.
The shot blast wheel assembly according to claim 11 wherein a peripheral groove is provided in the front face of the disc to receive the O-ring, such groove being angled outwardly.
The shot blast wheel assembly according to claim 12 wherein the cross-sectional axis of the angled groove is substantially perpendicular to the abutment surface of the backing means and to the corresponding surface of the blade.
A blade member adapted for use in the shot blast wheel claimed in any one of claims 1 to 13, the blade member being adapted to be mounted in radial orientation on a rotatable disc member, the blade member defining an engagement formation at or towards the radial outer extremity thereof which is adapted to engage a mating engagement formation defined by a shot blast wheel upon the urged radially outwardly by means of locking means.
The blade member according to claim 14 wherein the engagement formation is a spigot formation.
The blade member according to claim 14 or claim 15 wherein the spigot formation is angled between 10° and 70° relative to the rotational axis of the shot blast wheel.
The blade member according to claim 16 wherein the spigot formation is angled approximately 40° relative to the rotational axis of the shot blast wheel.
The blade member according to any one of claims 14 to 17 including an angled abutment surface at or towards the inner extremity of the blade adapted to be engaged by locking means thereby to urge the blade in a radially outward direction and in a direction towards the surface of the shot blast wheel.
The blade member according to claim 18 wherein the angle of the abutment surface is approximately 30° relative to the rotational axis of the wheel.
A blade member according to any one of claims 14 to 19 including an engagement formation comprising an elongated tongue formation on the lower longitudinal surface of the blade, the tongue formations being receivable in corresponding groove formations in a shot blast wheel disc permitting a small degree of radial movement to effect a locking function between the blade and the disc.
A shot blast wheel adapted for use in the assembly claimed in any one of claims 1 to 13 comprising a disc member adapted to be rotatably mounted and having a front surface whereon a plurality of generally radially disposed blade members are to be mounted, the disc member defining a plurality of radially disposed groove formations on a front surface thereof adapted to receive corresponding elongated tongue formations defined on the lower longitudinal surface of the blade members, and an engagement formation at or towards the outer zone of the groove which is adapted to engage a corresponding formation defined by the blade formation so as to prevent movement of the blade formation in a radially outward direction as well and in a direction away from the surface of the disc.
A disc member according to claim 21 wherein the engagement formation comprises a socket formation adapted to receive a corresponding spigot defined by a blade member.
The disc member according to claim 21 or claim 22 wherein the socket formation is angled between 10° and 70° relative to the rotational axis of the disc.
The disc member according to claim 23 wherein the socket formation is angled at approximately 40° relative to the rotational axis of the disc.
The disc member according to any one of claims 21 to 24 wherein the radially disposed groove formations terminate short of the outer periphery of the disc.
An impeller adapted for use in a shot blast wheel assembly according to claim 8 and claims 9 to 13 in as far as these are dependent on claim 8 characterised in an angled abutment surface in the form of a peripheral flange formation which is adapted to engage corresponding angled surface on a blade member in order to urge the latter radially outwardly and in a direction towards a shot blast disc.
The impeller according to claim 26 wherein the angled flange formation is angled at approximately 30° relative to the rotational axis of the shot blast wheel assembly.