Knock-out systems for foundries

An apparatus for use in a so-called knock-out or shake-out system for foundries comprises a beam which may be resiliently suspended by a stirrup and bellows. A pair of tubular frames depend from the ends of the beam and a pair of rectangular clamp frames are vertically slidable in the tubular frames. A mold box comprising a pair of box-frames and containing a metal casting in a sand mold is located between the two pairs of frames. Two sets of bellows one associated with each clamp frame are inflated to raise the clamp frames and clamp the box between the lower crosspiece of these frames and some other part of the structure such as the lower cross-piece of the tubular frames. The mold is vibrated by vibrators so that the sand and casting are shaken out of the box.

This invention relates to so-called knock-out or shake-out systems for 
foundries by which a metal casting is displaced from a box containing a 
particulate mold such as a sand mold. 
Sand molds for castings are generally contained in metal boxes, usually in 
a pair of open rectangular box-frames containing the cope and the drag 
respectively. A common way of removing the solidified castings from the 
molds is to place the boxes containing the molds on a vibrating grid, 
which shakes the sand loose and allows it to fall through the grid. 
The noise level in such a system is very high and comes mainly from two 
sources, namely the impact between the boxes and the grid, and the impact 
between adjacent boxes. The second source can be eliminated by keeping the 
boxes apart, but not the first. 
This invention arises from attempts to devise a system in which the noise 
level is significantly reduced, without reducing the rate of handling the 
molds, and possibly even significantly increasing the rate of handling the 
molds. 
According to the invention, an apparatus for displacing a metal casting 
from a box containing a particulate molds, comprises a structure adapted 
to be suspended in the air from above and to engage and support the box, 
and means to vibrate the structure so as to shake the particulate material 
from around the casting and thereby displace the casting from the box. 
In most cases the particulate material will be sand, although other 
refractory materials could be used. 
The structure may be vibrated by means of one or more vibrators of the type 
which employ pneumatically operated pistons or, particularly when heavy 
loads are to be handled, a vibrator of the rotary electric type may be 
used. The vibrator or vibrators may be mounted in any suitable position on 
the structure. 
The structure preferably includes at least one clamp which is adapted to 
grip the box during vibration so that there is less risk of noise being 
generated by relative movement between the box and the structure. 
Preferably the structure includes a pair of clamps adapted to grip opposite 
ends of the box and the clamps are preferably capable of being swung apart 
to facilitate their engagement and disengagement with the box. 
When the box comprises a number of box-frames, the clamp or clamps are 
preferably adapted to grip the box such that the box-frames are 
substantially incapable of relative movement during vibration, so as to 
eliminate this possible source of noise. 
In a preferred arrangement, the structure comprises a beam and a pair of 
frames one depending from each end of the beam, each frame being 
associated with a device for raising the frame relative to the beam so as 
to clamp part of the box between part of the frame and some other part of 
the structure. The box may be clamped by means of one or more suitable 
projections such as handles, studs, trunnions or flanges. 
Preferably the frames extend over the top of the beam and the devices for 
raising the frames are mounted on the beam and operate by exerting an 
upward force on the frames. 
The best kind of devices for raising the frames are those which are fluid 
operated, either by liquid or gas. Pneumatic bellows are especially 
preferred because they are relatively cheap, they have no moving parts 
which may wear or vibrate and they have a relatively small closed height. 
They also have the advantage that they are completely sealed and therefore 
do not suffer any ingress of sand or dirt. 
The vibrations produced during operation of the apparatus may be isolated 
from the lifting gear by adapting the structure to be resiliently 
suspended in the air, for example by the use of springs or a further set 
of pneumatic bellows. 
In an especially preferred embodiment of the invention, an apparatus for 
displacing a metal casting from a box containing a particulate mold, 
comprises a beam adapted to be resiliently suspended in the air, a frame 
depending from each end of the beam, and each frame being associated with 
a device which is adapted to lift the frame relative to the beam such 
that, when the box is located between the frames and beneath the beam, 
part of the box can be clamped between part of the frame and some other 
part of the apparatus so that the box can then be lifted into the air by 
the apparatus, and the apparatus further includes means to vibrate the box 
so as to shake the particulate material from around the casting whilst the 
box is suspended in the air and thereby displace the casting from the box. 
The frames may take various forms depending to some extent on the load 
which is to be lifted. In one arrangement the frames may each comprise a 
generally U-shaped member slidable in a pair of tubes which depend from 
the beam, and the tubes are preferably joined by a cross-member such that 
part of the box can be clamped between the cross-piece of the U-shaped 
member and the cross-member. 
Preferably the frames can be moved along the beam so as to adjust the 
distance between the frames to accommodate boxes of different sizes. 
The box may be clamped between the lower part of each frame and a 
projection on the underside of the beam or even the beam itself. This 
arrangement is particularly good where heavy loads are to be handled and 
the structure therefore needs to be relatively rigid.

In the apparatus shown in FIG. 1, a horizontal beam 1 of box-girder 
construction is supported at its mid-length by a stirrup 2 which embraces 
the beam without touching it. The beam rests on a set of air-filled 
bellows 3 which are located between the beam and the cross-piece of the 
stirrup 2. The upper ends of the arms of stirrup 2 are joined together by 
a cross-bar 4 for engagement by lifting gear, not shown, by which the 
apparatus may be suspended clear of its surroundings in use. The lifting 
gear could be an overhead gantry or a balancer-type work handler. 
A pair of sleeves 5 are slidably carried one on each end of the beam 1 and 
these sleeves are fixed in position on the beam by bolts 6. A number of 
bolt-holes 7 are formed in the beam to allow the sleeves to be fixed in 
various positions. Each sleeve 5 carries on its underside a longitudinally 
extending strap 8. A rectangular steel frame 9 is suspended from each 
strap 8 by one of its shorter sides 10a which rests on the strap. The 
longer sides of the frame 9, which extend vertically, are hollow and 
slidably guide a rectangular clamp frame 11. This clamp frame 11 comprises 
a U-shaped rod 12, the arms of which extend above the beam 1 and are 
screw-threaded at their upper ends to receive nuts 13 for securing a plate 
14 which forms the upper cross-piece of the clamp frame 11. A further set 
of air-filled bellows 15 are located between the plate 14 and the sleeve 5 
to support the clamp frame 11. 
Each frame 9 carries a pneumatic vibrator 16 of the type which employs 
reciprocable and cushioned pistons, and the vibrators are mounted so as to 
produce vibrations mostly in a vertical direction. 
In use, the apparatus is moved into position above a mold box 17 using the 
lifting gear. The mold box 17 comprises a pair of box-frames 18a, 18b, 
each box-frame having a pair of handles 19 at each end. The box contains a 
metal casting surrounded by sand 20 which it is desired to remove from the 
box. The clamp frames 11 are then manually swung apart and the apparatus 
is lowered until the cross-piece of the U-shaped rods 12 can be swung 
beneath the handles. When this has been done, the bellows 15 are inflated 
by compressed air so that the clamp frames 11 slide upwards within the 
tubular legs of frames 9 until the handles 19 are firmly clamped between 
the cross-piece of the U-shaped rods 12 and the lower cross-piece 10b of 
the frames 9, thus firmly clamping together the box-frames 18a and 18b. 
The apparatus is then positioned such that the box is suspended a few 
inches above a grid, not shown, and the vibrators 16 are switched on to 
vibrate the whole apparatus, including the mold box, to shake out of the 
box the sand and the casting. The bellows 3 substantially prevent the 
vibrations from being transmitted to the lifting gear. 
The length of time taken to shake the casting out of the mold box is no 
greater with this system than with previous knock-out or shake-out 
systems, and the time may even be reduced in some cases due to more 
efficient shake-out. 
When most of the sand has been shaken from the box and has fallen through 
the grid, and the casting has fallen onto the grid, the vibrators are 
switched off and the bellows 15 are deflated to allow the clamp frames 11 
to be swung clear of the box. The cycle may then be repeated using a fresh 
box. 
When a box need only be raised a relatively small distance the clamping 
action may impart sufficient lift to make the use of lifting gear 
unnecessary. 
Mold boxes of different sizes may be accommodated by removing the bolts 6 
and adjusting the position of the sleeves 5 on the beam 1 to give the 
required spacing between clamp frames 11. Mold boxes of different depths, 
and therefore having wider handle spacing, may be accommodated by 
adjustment of the position of the plate 14 on the threaded ends of the rod 
12 by means of nuts 13. 
In an evaluation under typical foundry conditions, the sound level produced 
by operation of this apparatus was found to be between 85 and 90 dB(A) as 
compared with previous knock-out or shake-out systems which often created 
sound levels well in excess of 100 dB(A). In a foundry environment this 
represents a significant noise reduction. 
A single vibrator mounted at the mid-point of the beam 1 may be used in 
lieu of the vibrators 16. 
The distance between the cross-pieces 10b and the cross-pieces of the 
U-shaped rods 12 may be adjusted by means of locking pins locatable in a 
series of holes in the ends of the rods, in lieu of the nuts and 
screw-threads. 
The apparatus just described above is of light-weight construction and is 
intended for handling relatively light loads. The apparatus shown in FIG. 
2 is constructed on the same principles as that of FIG. 1, but is intended 
for use with heavier loads. Parts which generally correspond to those of 
FIG. 1 have been given corresponding reference numerals. 
The beam 1 is of U-shaped cross-section and a suspension member 21 of 
inverted-U cross-section is bolted to the beam 1 at its mid-length. A 
lifting stirrup 22 embraces the cross-piece of member 21 without touching 
it, and bellows 3 are located between the stirrup 22 and suspension member 
21 to prevent vibrations being transmitted to the lifting gear. Each end 
of the beam 1 carries a pair of upwardly-extending forked supports 23 
which support a pair of depending clamp frames 24. 
Each clamp frame 24 comprises a generally U-shaped member 25 of which the 
upper ends of the arms are joined by a rod 26 which rests in supports 23. 
A web 27 connects the lower portions of the arms of member 25 and this web 
has a hole 28. A set of bellows 15 is located between each rod 26 and the 
beam 1. A pair of C-shaped bars 29 are attached to the underside of beam 
1, one at each end of the beam and running transversely of the beam. 
A high energy vibrator 30 of the rotary electric type is mounted on the 
beam 1 at about its mid length, beneath stirrup 22. 
The apparatus is used in a similar manner to that of FIG. 1. The apparatus 
is positioned above a steel mold box 31, and the clamp frames 24 are swung 
apart, pivoting on the forked supports 23. The mold box 31 comprises a 
pair of box-frames 32a, 32b, each having a pair of studs 33 fixed one at 
each end of the box-frame, only one of each pair being shown in the 
drawings. The clamp frames 24 are swung together, and the studs 33 of the 
lower box-frame 32b are located in the holes 28. The bellows 15 are then 
inflated to lift the clamp frames 24 off their supports 23 and, when the 
bellows have been inflated sufficiently, the upper and lower box-frames 
become firmly clamped between the C-shaped bars 29 and the lower part of 
the clamp frames 24. 
The box is then lifted into the air and vibrator 30 is energised to shake 
the sand and casting out of the box. 
Note that since the vibrator is of a rotary type it imparts a considerable 
horizontal as well as a vertical vibratory motion to the apparatus.