Note: Descriptions are shown in the official language in which they were submitted.
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POSITIONING APPARATUS
TECHNICAL FIELD
The present invention relates to an apparatus for positioning workpieces,
such as timber workpieces or profile bars whose length is to be adjusted, and
comprises: a feed conveyor by means of which the workpieces are fed with
their longitudinal direction substantially at right angles to the direction of
feed of the conveyor, transverse displacement devices disposed to displace
the workpieces in their longitudinal direction transversely of the direction
of
feed, and abutment means for arresting the transverse displacement
movement of the workpieces, whereby the one end of the workpieces is
positioned.
BACKGROUND ART
Positioning apparatuses of the type intimated by way of introduction are
previously known in the art. Such positioning apparatuses may be employed
for positioning various types of elongate workpieces, such as workpieces of
profiled material (for example aluminium and plastics), timber pieces etc.
Hereinafter the present invention will be exemplified in one embodiment in
which the workpieces are timber pieces.
In prior art positioning apparatuses for handling timber, the timber
workpieces are fed resting on a feed conveyor such that the longitudinal
direction of the timber pieces is transversely directed in relation to the
direction of feed of the conveyor. In the positioning operation proper, the
timber pieces are displaced in their longitudinal direction by means of
rollers
whose longitudinal directions are approximately parallel with the direction
of feed of the feed conveyor. As a result of action from these rollers, the
timber pieces will be displaced transversely of the direction of feed of the
feed conveyor. For positioning individual timber pieces, use is made of an
abutment against which the individual workpieces are displaced such that
the transversely directed displacement is arrested and thereby the ends of
3 5 the timber pieces become positioned. The abutment is placed in such a
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manner that it is located at the end regions of the rollers by means of which
the timber pieces are transversely displaced.
The above-described, prior art construction may function satisfactorily in
S such situations where the demands on output capacity are not too
exaggerated. If, thus, the speed of the feed conveyor is slow, the transverse
displacement need not take place at any high speed either, for which reason
the risk that the timber pieces strike the abutment and thereafter bounce is
slight.
If, on the other hand, the speed of the feed conveyor is increased, the
transverse displacement speed must also be increased, for which reason
bouncing occurs between the timber pieces and the abutment. As a result,
the precision in the sought-for positioning deteriorates considerably.
In many contexts, a combination of extremely tight tolerances is required as
regards the positioning of the individual timber pieces, often tolerances of
less than 1 mm. Simultaneously with this precision requirement, demands
are also placed on high feeding speed of the feed conveyor, in which event
speeds as high as 100 m/min. or more may come into consideration.
Such capacity output and precision requirements cannot be combined
employing prior art equipment.
2 S PROBLEM STRUCTURE
The present invention has for its object to design the positioning apparatus
described by way of introduction such that it may operate at highly
intensified speeds, at the same time as the requirements on precision in the
positioning operation may be placed extremely highly. The present
invention further has for its object to realise an apparatus which is
operationally reliable and simple in design and construction.
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SOLUTION
The objects forming the basis of the present invention will be attained if the
positioning apparatus intimated ty way of intxoduction is characterized in
that the abutanent means are disposed on a conveyor which ruts along and
synchronously in the same direction as the feed conveyor.
Suitably, it further applies according to the present invention that the
operative length of the transverse displacement device, seen in the direction
of Eeed of the feed conveyor, substantially corresponds with the operative
length of the conveyor of the abutment means.
As a result aF the above-described featwres, a construction will be realised
in
which the transversely directed morremEnt of the individual timber piece
may take place at relatively slow speed in relation to the abutment me~uns
even though the feed conveyor runs ~at high speed. As a result, the risk is
also eliminated of bouncing between the timber pieces and the abutment
means; and precision will be improved considerably. ,
BRIEF DESCRIPTION 4F THE ACCOMPANYING DRAWINGS
'tee present invenfiian will now be described in greater detail hereinbeiow,
with paztzcular reference to the accompanying Drawings. In the
accompanying Drawings:
Fxg. ~ is a schematic top plan view of the apparatus according to the
preset invention;
Fig. 2 shows the apparatus of Fig. 1 seen in the direction of the arrow
B in Fig_ 1;
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Fig. 3 shows a modified embodiment in a view corresponding to that
of Fig. l;
Fig. 4 shows the modified embodiment in a view corresponding to
S that of Fig. 2; and
Fig. 5 is a section taken along the section line A-A in Fig. 4.
DESCRIPTION OF PREFERRED EMBODIMENT
As was intimated above, the present invention may be applied in the
positioning of different types of elongate workpieces, such as workpieces of
tubular material, profiled material, timber etc. The material in the
workpieces may also vary. However, the present invention will be described
1 S for purposes of exemplification below in connection with the positioning
of
timber workpieces.
In Fig. 1, reference numeral 1 relates to chains, belts or the like which are
included in a feed conveyor for the timber pieces 2. The chains or belts move
in a feed direction according to the arrow 3. The chains 1 are supported by
means of suitable support members (not shown on the Drawing) and run
over wheels or the like (not shown). Further, the chains are provided with
drivers 4 which advance the workpieces 2 ahead of them.
The apparatus according to the present invention further includes transverse
displacement devices 5 which are intended for feeding the timber pieces in
their longitudinal directions transversely of the direction of feed of the
conveyor 1. The transverse displacement devices include at least two rollers
6 ar the like which are rotary in accordance with the arrows 7 around shafts
which are substantially parallel with the feed conveyor 1 and its direction of
feed 3. 'The upper surfaces of the rollers 6 are located on a slightly higher
vertical level than the upper sides of the feed conveyor 1. Hereby, the
rollers
6 will, when they rotate in accordance with the arrows 7, transversely
displace the timber pieces 2 in the direction of the arrow 8. At the same
time,
3 5 the timber pieces 2 will be displaced by the feed conveyor 1 in the
direction
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of the arrow 3, the timber pieces sliding on the rollers 6 in their
longitudinal
direction
Suitably, the shafts of the rollers 6 are aligned such that they deviate
5 somewhat from a parallel state with the direction of feed of the feed
conveyor 1 in such a manner that the rollers 6 impart to the timber pieces a
movement component in the same direction as the feed direction 3. Hereby,
the timber pieces 2 will be somewhat lifted forwards from the drivers 4 or at
least the friction against them will be reduced. The oblique inclination which
is required for achieving such a result implies that the right-hand ends of
the
rollers 6 in Fig.1 are to be displaced in an upward direction in the Drawing.
The apparatus according to the present invention further includes a second
conveyor 9 which has chains, belts or the like 10 which run over wheels 16
shown in Fig. 2, with centre axes 11. The chains 10 in the conveyor 9 are
mutually interconnected via a number of crosspieces 12 which are provided
with anchorages for abutment means 13. The conveyor 9 displays the same
direction of movement as the feed conveyor 1 and runs synchronously with
it. Further, its direction of movement is substantially parallel with the
direction of movement 3 of the feed conveyor. The synchronous movement
is further such that one crosspiece 12 always follows the position of one
timber piece 2 ahead of a driver 4 on the feed conveyor 1.
On the Drawings, the abutment means 13 have, for simplicity's sake, been
illustrated as pins of circular cross section. However, precision gains may be
made if they are platform or buffer in shape so that they cover and abut
against the greater part of the end surfaces 14 of the timber pieces.
In the position a in Fig. 1, one of the crosspieces 12 is located in register
with
a timber piece 2 which has just been fed in on the transverse displacement
devices 5. This implies that the timber piece in position a begins to move in
a
direction towards the conveyor 9 and the abutment means 13 disposed
thereon. In position a, the previously mentioned movement has just begun,
for which reason the end 14 of the timber piece is located a distance from the
3 5 adjacent abutment means 13.
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As the timber pieces 2 are fed in the direction of feed 3, they are also
displaced in the transverse displacement direction 8 in a direction towards
the abutment means. In position b, this displacement has been completed so
that the end 14 of the timber piece 2 is located in contact with the abutment
means 13.
For fine calibration of the positioning of the timber pieces 2, an abutment
rail
is disposed at the discharge end of the conveyor 9, the abutment rail being
adjustable in a direction towards and away from the feed conveyor 1
10 corresponding to the relevant abutment means 13. When the timber piece
passes from b to position c at the abutment rail, the end 14 of the timber
piece will slide along this rail so that all tendencies towards bouncing and
the like will have time to fade. At the discharge end of the abutment rail 15,
the transverse displacement devices 5 with their included rollers 6 also
15 terminate, so that, after the passage of the abutment rail 15, there no
longer
exists any force transversely of the direction of feed 3. In this state, the
timber
pieces are thus positioned with the end 14 in an extremely accurate manner.
Fig. 2 shows the apparatus according to Fig. 1 seen in a pure horizontal side
elevation in the direction of the arrow B. It will be apparent from Fig. 2
that
the chain or belt 10 in the conveyor 9 runs over wheels 16 with the above-
mentioned centre axes 11. In Fig. 2, the abutment means 13 are shown
schematically and are illustrated only in the form of upstanding pins.
It will be apparent from Fig. 1 that the crosspieces 12 in the conveyor 9 have
a plurality of fixed positions for the abutment means 13. In all of these
positions, there are abutment means, but these are movable between
upwardly directed, active positions and retracted, passive positions. This is
realised in that the abutment means 13 are displaceable in the crosspieces 12
between the active position illustrated at the upper part of the conveyor 9 in
Fig. 2 to the retracted, passive position which is shown at the lower part of
the conveyor:
For switching the abutment means between the active and the passive
3 S positions, an activator 17 and a recuperator 18 are employed.
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The recuperator is technically in the form of a guide plate 19 against which
the outer ends of the abutment means 13 come into contact, the abutment
means being urged into their sockets in the crosspieces 12 to the passive
position. This is realised in that the guide plate 19 and the lower part of
the
conveyor 9 form a cuneiform space which tapers in the direction of
movement of the conveyor.
In a corresponding manner, the activator 17 has a number of guide rails 20
which are disposed to form, on the lower part of the conveyor 9, a cuneiform
space tapering in the direction of movement of the conveyor. When an
abutment means 13 enters into this space and comes into contact with the
guide rail 20, the abutment means is urged through its socket in the
crosspiece 12 out to the active position. The guide rails 20 which are the
same
in number as the number of rows of abutment means 13 (see Fig. 1), are
switchable between the active position illustrated in Fig. 2 by means of a
switching device in the form of a cylinder unit 21. On retraction of the
cylinder unit 21, the left-hand end of the guide 20 in Fig. 2 is lifted in an
upward direction so that an abutment means 13 may pass without being
urged out to the active position. Given that the abutment means can, in this
manner, be activated in rows to the active positions or pass the activator 17
without being activated, the positioning of the ends 14 of the timber pieces 2
may be varied stepwise with great accuracy.
DESCRIPTION OF ALTERNATIVE EMBODIMENTS
Figs. 3-5 show a slightly modified embodiment of the present invention. In
Fig. 3, the reference numerals from Fig. 1 have been inserted, and it should
be observed that the design, construction and function of the feed conveyor 1
and the transverse displacement device are unchanged. That which has been
changed in this embodiment is merely the conveyor 9 and the anchorages of
the abutment means 13 therein.
In the embodiment according to Figs. 3-5, the abutment means are one in
number per crosspiece 12 in the conveyor 9 and, further, the abutment
3 5 means are displaceable along the longitudinal direction of the crosspieces
12.
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It will be apparent from Fig. 4 that the abutment means 13 on the inside of
the conveyor 9 have guide bodies 22 which are disposed for displacement of
the abutment means along the crosspieces 12. The guide bodies 22 are place
so as to cooperate with a recuperator 18 and an activator 17 in a manner
which is analogous with that described above with reference to Fig. 2. The
recuperator 18 includes a guide rail 23 which is obliquely inclined in
relation
to the direction of movement of the lower part of the conveyor 9. When a
guide body 22 comes into abutment against the guide rail 23, the guide body
and the connected abutment means 13 are displaced in the longitudinal
direction of the associated crosspiece 12 in order to be placed at the end of
the crosspiece located most proximal the feed conveyor 1. This corresponds
to a displacement of the guide body 22 from position d to position a in Fig.
5.
The activator 17 in the embodiment according to Figs. 3-5 has been designed
as a guide profile 24 in which the guide bodies 22 may be accommodated
and displaced in the longitudinal direction of the guide profile. The guide
profile is pivotally-secured at its end located in position a in order there
to
accommodate a guide body 22 in a recuperated position, and thereafter lead
the guide body to the activated position in position f. For displacement and
adjustment of the guide profile 24, there is provided a switching unit in the
form of a piston/ cylinder unit. The switching unit 25 is further provided
with two mutually guide plates 26 which impart a terminal and accurate
positioning to the abutment means 13 and the associated guide body 22.
Finally, the embodiment according to Figs. 3-5 suitably includes some
appropriate mechanism for locking the abutment means 13 in the adjusted
longitudinal position along the crosspieces 12.
The present invention may be modified further without departing from the
scope of the appended Claims.
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