Blade for centrifugal blasting wheels

A blade for use in two different forms of centrifugal blasting wheels. The blade comprises a body generally in the form of a parallelepiped having an inner and an outer end and side flanges to define a blade which is I-shaped in transverse cross-section. The blade includes a first pair of laterally extending retaining lug formations which are adapted to engage the inner annular surfaces of the wheel plates of a first wheel thereby to retain the blade in place. Each of said first lug formations is arcuate and formed at a common radius with a pair of second retaining lug formations which extend from the side flanges of the blade in directions generally at a right angle to the direction the first lug formations extend from such side flanges. When the blade is used in a second wheel, the second lug formations engage abutment surfaces formed in recesses in the wheel plates thereby to retain the blade in place in the second form of blasting wheel.

The present invention relates to blades for centrifugal blasting wheels of 
the type adapted to throw particulate material by centrifugal force from 
the outer ends of the blades onto an object or surface to be abraded, 
cleaned, or otherwise engaged by the particulate material for surface 
treatment. In particular, the present invention relates to a new and 
improved blade adapted to be used in two or more different types of such 
blasting wheels. 
One form of airless centrifugal blasting wheels of the type described is 
marketed by Wheelabrator-Frye Inc. under the trademark WHEELABRATOR. Such 
wheel consists of a pair of spaced parallel annular plates having a number 
of blades extending radially between the plates in equally 
circumferentially spaced relationship. The blades are removably secured in 
place so that they may be readily changed for replacement purposes due to 
wear. 
Means are provided for rotating the wheel at high speed about a central 
axis and for dispersing particulate material onto the inner end portions 
of the blades whereby the particulate material is dispersed by 
centrifrugal force outwardly over the surface of the blades and projected 
at high velocity from the ends of the blades. An impeller is provided in 
the central opening formed by the annular blades for feeding the 
particulate material onto the inner ends of the blades. A stationary 
control gage surrounds the impeller for controlling the passage of 
particulate material to the blades thereby controlling the direction as 
well as the blast pattern of the particulate material thrown from the ends 
of the blades. 
The annular side plates of the wheel just described are provided with 
respective crosswise aligned grooves in their inner faces extending 
radially in equally circumferentially spaced relation from the inner 
annular surfaces of the plates to the outer surfaces thereof. Each blade 
is generally in the form of a parallelepiped having inner and outer ends 
and side flanges to define a blade which is I-shaped in transverse 
cross-section. The blade is provided with a pair of operatively disposed 
retaining lugs adjacent its inner end. These retaining lugs engage the 
inner annular surfaces of the wheel plates thereby to retain the blade in 
place with its side flanges received within the radially extending grooves 
in the inner surfaces of the side plates. This construction also permits 
ready removal of the blades for replacement purposes. A wheel with blades 
of the type just described is disclosed in the application of Harold F. 
Schulte et al., Ser. No. 70,478, filed Sept. 24, 1979, now U.S. Pat. No. 
4,333,278, and assigned to the assignee of the present application. 
There are other forms of centrifugal blasting wheels being marketed which 
are generally the same as the wheel just described. However, these wheels 
differ in the configuration of the various surfaces on the blade and the 
wheel plates which interengage to retain the blade in place. 
In the form of wheel now under consideration, the wheel plates are also 
provided with respective crosswise arranged recesses which open into the 
inner annular surfaces of the wheel plates thereby interrupting such 
surfaces. Each pair of radially extending grooves communicates with a 
respective pair of said recesses and with the outer annular surfaces of 
the wheel plates. Each of such recesses extends circumferentially of the 
wheel plate beyond the adjacent walls which are in parallel spaced 
relation and which define, at least in part, the radially extending 
grooves. These recesses thus define pairs of abutment surfaces spaced from 
the inner annular surfaces of the wheel plates. Each blade is provided 
with lug formations which engage these abutment surfaces thereby to retain 
the blade in place during operation of the wheel and which permit removal 
of the blade for replacement purposes by movement of the blade radially 
inwardly of the wheel. 
It is a principal object of the present invention to provide a blade which 
is configured for use in either of the two types of wheels described 
above. 
It is another object of the present invention to provide a blade for use in 
two different forms of blasting wheels, which blade has a first pair of 
retaining lug formations arranged to engage the inner annular surfaces of 
the wheel plates of a first wheel thereby to hold the blade in place, and 
which blade has two additional pairs of retaining lug formations adapted 
to engage abutment surfaces formed in recesses in the side plates of a 
second wheel thereby to retain the blade in place in such second wheel.

Referring particularly to FIGS. 1 through 4, the blade of the present 
invention, generally designated 10, includes a web portion 11 and side 
flanges 14 and 15. As noted, the body of the blade is generally in the 
form of a parallelepiped with the side flanges and web defining an 
I-shaped transverse cross-section. 
The web 11 of the blade is formed with faces 17 and 18. These faces are 
substantially planer with the inner end portions thereof being slightly 
curved as at 17a and 18a, for receipt of particulate blasting material 
with a minimum of abrasive wear. At this juncture, it should be pointed 
out that the inner end of the blade is shown to the left in FIGS. 1 
through 3. 
The side flanges 14 and 15 of the blade are received within radially 
extending grooves in the side plates of the blade as will be explained in 
detail below. The side flanges include ears 20 and 21 which may be 
received within the grooves just mentioned to aid in positioning of the 
blade. 
The blade is provided with a pair of retaining lugs 24 and 25 which extend 
from respective side flanges 14 and 15. The lugs extend laterally from the 
side flanges and define a first pair of retaining lug formations 24a and 
25a. As noted in FIGS. 1 and 3, the lugs are thicker than the side flanges 
of the blade. As best seen in FIG. 4, the lug 24 is configured such that 
it includes a pair of retaining lug formations 24b and 24c. In like 
manner, the retaining lug formation 25a joins with a pair of retaining lug 
formations 25b and 25c. 
The lug formations 24b, 24c, 25b and 25c may be characterized as extending 
from the blade body in directions which are generally at a right angle to 
the direction the lug formations 24a, 25a extend from the blade. As noted 
in FIGS. 1 and 2, all of the various retaining lug formations have an 
arcuate shape and are formed with a common radius. Thus, the lug formation 
24a, for example, joins with the lug formations 24b and 24c in a smooth 
and continuous manner. 
At this juncture, it should be made clear that the blade is symmetrical 
with the plane 28 indicated in FIG. 3. As will become clear from the 
description of the wheel to follow, the plane 28 contains the axis of 
rotation of the wheel when the blade is operatively mounted in place. Of 
course, the blade is also symmetrical with respect to a plane 
perpendicular to the plane just mentioned and containing the longitudinal 
central axis of the blade. 
Referring now to FIG. 5, a centrifugal blasting wheel of the type marketed 
under the trademark WHEELABRATOR is generally designated 30. This wheel 
includes a pair of front and back annular wheel plates 31 and 32 
respectively. These plates are secured to each other in parallel spaced 
relationship by circumferentially disposed spacers 34 which extend through 
laterally aligned openings 35 in the wheel plates. The portion of each 
spacer extending between the plates is protected by a sleeve 37 formed of 
hard wearresistant material and dimensioned to have a length corresponding 
to the space between the wheel plates. 
The front and back wheel plates 31 and 32 are formed with a crosswise 
aligned pairs of radially extending grooves 38 spaced circumferentially 
along the inner surfaces of the wheel plates for receipt of the blades 10. 
As noted in FIG. 6, each groove 38 of the plate 32 is formed in part by 
parallel opposed walls 38a and 38b. It will be understood that the wheel 
plate 32 is of identical but opposite-hand construction with respect to 
the wheel plate 31. 
A blade 10 is provided for each of the pair of crosswise aligned grooves 
38. Each blade is mounted in place by being inserted within the central 
opening of the wheel defined by the inner annular surfaces 40 and 41 
formed by respective wheel plates 31, 32. As noted in FIG. 6, each groove 
38 opens into or communicates with the inner annular surface 41. 
Similarly, the grooves 38 open into the outer annular surfaces 42, 43 
defined by respective wheel plates 31, 32. 
Each blade 10 is retained in place by engagement of the retaining lug 
surfaces 24a and 25a with respective inner annular surfaces 32 and 31. 
Referring to FIG. 6, for example, it will be understood that the retaining 
lug formation 24a engages the inner annular surface 41 at the shaded area 
indicated as 45. 
Hence, each blade is retained in place under the influence of centrifugal 
force with the retaining lug formations in abutting engagement with the 
inner annular surfaces. The side flanges 14 and 15 of each blade are 
received within the grooves 38 in closely spaced relationship with the 
walls 38a and 38b. The blades may be readily removed, for replacement 
purposes, through the central opening defined by the annular surfaces 40 
and 41. 
As noted in FIG. 5, the impeller of the centrifugal blasting wheel includes 
an annular flange 47 provided with slots 48 for receiving the inner ends 
of the blades 10. This engagement between the blades and the slots insures 
that the impeller rotates in timed relationship with the blades for proper 
feeding of the particulate material, all as more fully explained in the 
aforementioned Schulte et al., U.S. Pat. No. 4,333,278. 
Reference is now made to FIGS. 7 and 8 showing another form of centrifugal 
blasting wheel. The parts of this wheel which correspond to the parts of 
the wheel already described are indicated by the prime form of numeral. 
Each grove 38' communicates with a recess or pocket 50. This recess opens 
into the annular surface 41' and interrupts the same. Again, it will be 
understood that the wheel plates 31' and 32' are of identical but 
opposite-hand construction. 
It is noted that the recess 50 extends circumferentially of the groove 38' 
beyond the opposed walls 38a' and 38b'. Thus, the recess 50 defines a pair 
of abutment surfaces 50a and 50b. As noted in FIG. 8, the recess 50 has a 
depth greater than the depth of the groove 38'; thus, the recess 50 may 
define another abutment surface 50c. 
It will be understood that a blade 10 is mounted between each pair of 
crosswise aligned grooves 38' in the wheel 30'. The blades are held in 
place primarily by use of the retaining lug formations 24b, 24c, 25b and 
25c. For example, it will be understood that the retaining lug formations 
24b and 24c will be in abutting engagement with respective abutment 
surfaces 50a and 50b. 
As just indicated, the blade 10 is designed such that it may be held in 
place in the wheel 30' only by using the retaining lug formations 24b, 
24c, 25b and 25c. However, it may be desired to configure the surfaces 50c 
to aid in retaining the blades in place. This is achieved by forming the 
surface 50c with the same radius that defines the abutment surfaces 50a 
and 50b. Accordingly, when the blade 10 is mounted in the wheel 30', the 
retaining lug formations 24a and 25a will engage the abutment surfaces 50c 
at the same time as the other retaining lug formations on the blade engage 
the abutment surfaces 50a and 50b. 
Thus, it will be seen that the present invention provides a blade which may 
be used in two different forms of centrifugal blasting wheels. It will be 
understood that changes may be made in details of construction, 
arrangement and operation without departing from the spirit of the 
invention, especially as defined in the following claims.