Apparatus for removing the upper waste layer resulting in cutting plastic porous concrete blocks or the like

The apparatus for removing the waste layer arising in cutting porous concrete blocks comprises a beam (1) which extends above the porous concrete block in its longitudinal direction and can be raised and lowered, and at least two horizontal support frames (2, 2') mounted thereon and movable in height, which are arranged in pairs opposite one another to the two sides of a vertical central plane (M) of the beam (1) and beneath the same. A plurality of spikes (5, 5') which can be stuck into the waste layer are provided on the underside of each support frame (2, 2') and are aligned with their points facing down at an angle. All spikes (5) of the first support frame (2) of each frame pair (P) are parallel to one another and inclined at an acute angle (.mu.) to the longitudinal central plane (M) and all spikes (5') of the opposite second support frame (2') are parallel to one another and inclined at an opposite acute angle (.mu.l) to the longitudinal central plane (M). Each support frame (2, 2') is movable relative to the beam in the direction (B or C) of its spikes (5, 5').

FIELD OF THE INVENTION 
The invention generally relates to a cutting machine for cutting concrete 
blocks and in particular, to an apparatus of the cutting machine for 
removing a waste layer from the concrete blocks. 
BACKGROUND OF THE INVENTION 
Porous concrete blocks are cast in molds and demolded after attaining their 
green strength. The still plastic (green) porous concrete block, which has 
a length of about 6 to 7.5 m, a width of about 2 m and height of about 65 
to 75 cm, is taken to a cutting machine and cut there by means of 
tensioned steel wires in the longitudinal and transverse directions, so 
that rectilinear porous concrete bricks, blocks or even slabs result. 
These are then hardened under steam pressure in an autoclave. On cutting 
the still plastic porous concrete block, a layer about 3 to 12 cm thick is 
separated from the upper side and has to be removed before hardening. If 
the porous concrete block is cut lying horizontal, this waste layer is a 
layer of irregular height arising in blowing up the porous concrete mass. 
Porous concrete blocks are however according to DE-PS 958 639 also tipped 
over through 90.degree. after removal from the mold, so that they then 
stand on their long narrow side, and are cut precisely in this position. 
After the cutting the porous concrete block is then turned over through 
90.degree. again on to its major wide side (cf. DE-PS 2 108 300), before 
placement in the autoclave. In cutting a block standing edgewise also, a 
waste layer of up to 12 cm thickness is taken off at the top, because the 
narrow side of the plastic porous concrete block can be contaminated by 
mold oil, the sidewall of the mold is not exactly flat or even runs mostly 
at a small angle to the wide side of the porous concrete block and because 
moreover, depending on the format of the bricks or slabs to be cut, there 
is a residue which is taken into account in the upper layer. 
A known apparatus for removing the waste layer resulting in cutting the 
upper side of plastic porous concrete blocks or the like (DE-PS 1 683 837) 
comprises a suction box which can be lowered from above over the block and 
has a plurality of apertures in its underside. A cover arrangement in the 
form of a flexible film is provided beneath these apertures and can be 
drawn over a part of the apertures like a blind, in order to cover them. 
In this manner the apparatus can be used to lift off waste layers of 
different sizes. The known apparatus is however expensive to manufacture 
and operate. Since it operates with a vacuum and dust and porous concrete 
particles get into the suction air when sucking up the waste layer, 
filters for dust removal from this air are needed and regularly have to be 
cleaned. If the vacuum suddenly disappears because of loss of current or 
other disturbance to operation, the waste layer lifted off by the 
apparatus can moreover come away from the suction box and fall down on to 
the already cut porous concrete block located thereunder. This is already 
enough to damage the uppermost porous concrete bricks or slabs, which are 
then also waste, even with removal of the broken up waste layer by hand. 
The object of the invention is to provide an apparatus for removing the 
waste layer arising in cutting porous concrete blocks, especially porous 
concrete blocks or the like standing on edge, which can be made 
inexpensively, involves small operating costs and also has a long working 
life. 
SUMMARY OF THE INVENTION 
Such an apparatus is characterized according to the invention by a beam 
which extends above the porous concrete block in its longitudinal 
direction and can be raised and lowered, at least two horizontal support 
frames mounted thereon and movable in height by motor, which are arranged 
in pairs opposite one another to the two sides of a vertical central plane 
of the beam and beneath the same, and a plurality of spikes which can be 
stuck into the waste layer and are provided on the underside of each 
support frame and are aligned with their points facing down at an angle, 
wherein all spikes of the first support frame of each frame pair are 
parallel to one another and inclined at an acute angle to the longitudinal 
central plane and all spikes of the opposite second support frame are 
parallel to one another and inclined at an opposite acute angle to the 
longitudinal central plane, and wherein each support frame is movable 
relative to the beam in the direction of its spikes. 
The invention is thus based on the concept of engaging the waste layer by 
means of a plurality of spikes, which are stuck down obliquely into the 
waste layer from two opposite sides and then are lifted up synchronously 
by means of the support frames, purely mechanically, i.e. without suction 
air, to engage and lift the layer up from the rest of the porous concrete 
block. Since there is no suction air contaminated with dust and porous 
concrete particles, any air filters and servicing the same can be 
obviated. The apparatus itself consists of relatively simple mechanical 
components and only needs a relatively small amount of drive power, so 
that it can be made inexpensively and also only involves small operating 
costs in use. In the apparatus according to the invention the spikes are 
held in "gripping position" in the waste layer as soon as they are stuck 
into this, by the weight thereof and the weight of the movable parts of 
the apparatus, so that the waste layer engaged by the spikes cannot drop 
off in the event of a sudden power failure, e.g. loss of current. 
Advantageous arrangements of the invention are characterized in the 
dependent claims.

DETAILED DESCRIPTION 
The apparatus according to the invention is a component of a cutting 
machine for cutting a plastic porous concrete block standing on its long, 
narrow side. The apparatus is arranged in this cutting machine above the 
long, upper, narrow side of the porous concrete block and comprises a beam 
1 which can be raised and lowered in a frame, not shown, and extends 
parallel to the long, narrow side of the porous concrete block. Below the 
beam 1 there are a plurality of pairs P of support frames 2, 2'. The 
support frames 2, 2' are arranged in pairs opposite on another to the two 
sides of a vertical central plane M. A plurality of support rails 3, 3' 
are welded to the undersides of these horizontal support frames 2, 2' and 
extend perpendicular to the vertical longitudinal central plane M. The 
support rails are spaced from one another by a distance a in the manner of 
the tines of a rake and project beyond the mutually facing long sides 2a, 
2'a of each frame pair P. As can be seen from FIG. 3, the support rails 3 
of the first support frame 2 engage in the gaps between the support rails 
3' of the second support frame 2', and vice versa. 
The support rails 3, 3' are each formed as a C-section open downwardly, as 
is seen especially in FIG. 5. A spike strip 4 can be slipped into this 
C-section from the end of each support rail 3, 3' and consists for example 
of an aluminum alloy. 
A plurality, e.g. six, of long spikes 5 are arranged obliquely on each 
spike strip 4, equally spaced from one another and parallel to one 
another, so that they project downwardly at an angle from the spike strip 
4. The spikes 5 of the first support frame 2 are inclined at an acute 
angle .mu. of approximately 25.degree. to 35.degree., preferably 
30.degree. to the longitudinal central plane M. All spikes which are 
associated with the first support frame 2 run parallel to one another and 
are inclined at the same angle .mu. to the longitudinal central plane. The 
first support frame 2 is movable in the direction B, which runs parallel 
to the longitudinal direction of the spikes 5, relative to the beam 1. The 
spikes 5' of the second support frame 2' are arranged in like manner in 
the spike strips, which are slipped into the support rails 3', while all 
spikes which are associated with the second support frame 2' are arranged 
parallel to one another but are inclined relative to the longitudinal 
central plane M at an acute angle .mu.' which is opposite to the acute 
angle .mu.. The angle .mu.' can be of the same magnitude as the angle 
.mu.. An angle of 25.degree. to 35.degree., preferably 30.degree., has 
surprisingly proved to be especially advantageous, since large holding 
forces are hereby attained in the relatively soft, plastic porous concrete 
and there is the least danger of breaking out of this porous concrete. The 
second support frame 2' is movable in the longitudinal direction of its 
spikes 5' in the direction C relative to the beam 1. 
The spikes 5, 5', which advantageously have a length of about 200 mm and a 
diameter of 2.5 to 5 mm, preferably approximately 3 mm, are pushed from 
above into respective oblique bores 7 in the spike strips 4, so that their 
tips are directed downwardly and their heads are located in a countersink 
on the upper side of the spike strip. When the spike strip 4 is pushed 
into the support rail 3 or 3', the heads of the spikes can abut the inside 
of the support rail 3 and they are thus securely held. If there is a 
breakage or bending of a spike, the associated spike strip 4 can easily be 
pulled out of the support rail 3 and the damages spike be replaced by a 
new one. In order that the spike strips 4 shall be held in the associated 
support rails 3, each support rail 3 has a spring clip 8 at one of its 
ends, which partially covers the end opening of the support rail 3, while 
a fixed lip 9 at the other end serves as a stop for the spike strip. 
In order to mount the support frames 2, 2' movably, for shifting the 
height, each of the frames has two guide rods 10, 10', which are inclined 
as the same acute angle .mu., .mu.' relative to the longitudinal central 
plane M as the associated spikes 5, 5'. A correspondingly inclined guide 
bush 11, 11' is provided for each guide rod 10, 10' on the beam 1, the 
associated guide rods 10, 10' sliding in these bushes. 
There are six support frames 2 or 2' of like structure arranged on each 
side of the longitudinal central plane M of the beam 1. In order that 
these can be synchronously moved up and down, a common adjusting motor 13 
is provided for each beam side in the illustrated embodiment, being in the 
form of a stepping motor. The adjusting motor 13 drives an adjusting gear 
16 for each support frame 2 or 2' through bevel gearing 14 and a plurality 
of shaft sections 15. The adjusting gear 16 comprises a spindle nut driven 
through bevel gearing and which surrounds a threaded spindle 17 running 
parallel to the guide rods 10 or 10'. On rotation of the spindle nut the 
threaded spindle is displaced relative to the adjusting gear 16 and thus 
moves the associated support frame 2 or 2' in the direction B or C (FIG. 
1). In this manner all support frames 2 or 2' on one side of the beam 1 
can be moved synchronously up and down. The two adjusting motors on the 
two sides of the beam 1 can be coupled by a so-called electric shaft, so 
that all support frames 2 and 2' on the two sides of the beam can be moved 
up and down synchronously. It would also be possible to provide each 
support frame with its own adjusting motor and to synchronise the 
adjusting motors among themselves by electric shafts. Hydraulic or 
pneumatic adjusting motors could also be used. 
As already explained above, the waste layers to be lifted off can have 
different thicknesses. A waste layer A with the largest anticipated 
thickness D is shown in FIG. 2. The thickness if the waste layer increases 
over the width of the waste layer in the example shown as a result of an 
obliquely inclined sidewall of the casting mold. There are however also 
molds with sidewalls which run accurately parallel to one another 
perpendicular to the bottom, so that the waste layer then has a uniform 
thickness over its width. In order that the waste layer will be securely 
carried by the spikes 5, 5', it is necessary for the spikes to penetrate 
for approximately the whole thickness D into the waste layer. They should 
not however stick right through the waste layer, since the upper sides of 
the porous concrete bodies lying below the waste layer would otherwise be 
damaged. For this reason it is advantageous for the depth of penetration 
to be so adjusted that a safety margin of for example 5 mm remains between 
the lower bounding surface of the waste layer and tips of the spikes 5, 
5'. In order that waste layers whose thickness if less than the thickness 
D shown in FIG. 2, the stroke of the support frames 2, 2' in the direction 
of the associated spikes 5, 5' is adjustable. The adjustment of this 
stroke is effected with the aid of the adjusting motor 13 in the form of a 
stepping motor. 
In the illustrated embodiment there is further a sheet metal plate 18 
arranged some distance below the support frames 2, 2' and fixed to the 
beam 1 by vertical supports 19. The sheet metal plate 18 is arranged 
substantially horizontally, where a slight inclination relative to the 
horizontal is to be comprehended by this, where the angle of inclination 
relative to the horizontal corresponds to the angle of inclination of the 
mold sidewalls relative to the vertical. A foam rubber sheet 20 is 
provided on the underside of the sheet metal plate 18. The sheet metal 
plate 18 with the foam rubber sheet 20 serves in the first place to 
support the porous concrete block during transverse cutting. The 
transverse cutting is effected in that a plurality of wires under tension 
in a frame are moved through the porous concrete block by moving the frame 
from below upwards. In order that the plastic material of the porous 
concrete block shall not break out at its upper narrow side when the wires 
get into the vicinity of the upper narrow side, the upper narrow side is 
supported by the sheet metal plate 18 and the foam rubber sheet 20. The 
cutting wires bear on the foam rubber sheet 20 when the transverse cutting 
operation is complete. 
In order that the spikes 5, 5' can pass through the sheet metal plate 18, 
this is provided with a sufficiently large aperture 21, e.g. a bore, in 
the region of each spike 5, 5'. The foam rubber sheet 20 does not need to 
have any apertures, since it is simply pierced by the sharp spikes 5, 5'. 
When the spikes 5, 5' are withdrawn upwardly out of the foam rubber sheet 
20 on raising the support frames 2, 2', the foam rubber sheet 20 together 
with the sheet metal plate 18 serves as a stripper, which strips off 
porous concrete residues possibly adhering to the spikes 5, 5'. Since the 
stripped residues are on the underside of the foam rubber sheet 20, the 
simply fall away. 
The manner of operation of the novel apparatus is as follows: 
The porous concrete block lying on its long, narrow side, is firstly cut in 
the longitudinal direction by horizontal cutting wires, whereby an upper 
waste layer is separated off by a cutting wire in the uppermost position. 
The beam 1 is located with the support frames 2, 2' and the sheet metal 
plate 18 arranged thereon in its upper position, so that the movement of 
the longitudinal cutting frame is not hindered. After completion of the 
longitudinal cutting the beam 1 is lowered vertically, the support frames 
2, 2' being in the release position shown in FIG. 1. The lowering of the 
beam 1 is effected so far that the foam rubber sheet 20 bears on the upper 
narrow side of the porous concrete block. The transverse cutting is then 
effected from the bottom up, until the cutting wires bear on the foam 
rubber sheet 20. By actuating the adjusting motors 13 the support frames 
2, 2' are now displaced obliquely downwards, so that the spikes 5, 5' are 
stuck into the waste layer obliquely from two opposite sides, until their 
tips are located a safety distance of 5 mm above the lower bounding 
surface of the waste layer. This engagement or holding position of the 
support frames 2, 2' and their spikes 5, 5' is shown in FIG. 2. In this 
position of the support frames 2, 2' the beam 1 is raised again, so that 
the spikes 5, 5' stuck into the waste layer raise this. Since the spikes 
of each spike strip 4 are arranged at a mutual horizontal spacing of about 
90 mm and the horizontal spacing of one row of spikes 5 relative to the 
next row of spikes 5' only amounts to about 40 mm, the waste layer is held 
by a plurality of spikes at relatively small spacings. After the waste 
layer has been raised in the manner described, the porous concrete block 
cut in the longitudinal and transverse directions is tilted back through 
90.degree. on to its wide side and then put in an autoclave. As soon as 
the porous concrete block has been removed from the region below the beam, 
the support frames 2, 2' are moved obliquely upwards by means of the 
adjusting motors 13, out of their lower, gripping or holding position, so 
that the spikes 5, 5' are withdrawn from the waste layer. This thus loses 
their support and falls down on to a conveyor belt provided at the bottom 
of the cutting machine, through which the waste layer, which has broken up 
in falling, is carried off. The still plastic porous concrete mass of the 
waste layer is mixed as so-called fresh waste of the porous concrete mass 
of a further charge.