Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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TITLE OF THE INVENTION
DOUBLE ACTING LOG SINGULATOR
FIELD OF THE INVENTION
This invention relates to power driven conveyors having a plurality of driven
sections. In particular this invention relates to devices for unscrambling and
singulating
logs.
BACKGROUND OF THE INVENTION
United States Patent No. 5,257,688 to Fridlund discloses a log singulator
comprising a laterally spaced series of stationary steps which are interposed
between a
laterally spaced series of moving steps. The moving surfaces reciprocate to
urge logs
from an infeed location where the logs are received in a scrambled state
toward the
outfeed end where the logs are delivered one at a time. Singulation is
achieved by
selecting the height of the steps to minimize the number of logs promoted to
the next step
at each cycle.
United States Patent No. 5,423,417 to Redekop discloses a log singul~tor
having
laterally spaced lift arms that rotate between a plurality of laterally spaced
stationary
steps to promote logs from one step to the next.
United States Patent No. 5,351,729 to Brisson also discloses a singulator
comprising a set of laterally spaced stepped stationary plates and laterally
spaced moving
steps.
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The foregoing arrangement of laterally spaced sections is typical of many
prior art
log singulators. However, because the use of laterally spaced multiple
sections involves
several gaps between the sections, debris tends to fall between the gaps. Such
debris has
the potential to interfere with the drive mechanisms for the singulator. It
also represents
potential wood fibre which is either wasted or requires effort to recover. In
any event,
such debris accumulates and requires periodic cleaning.
It is an object of this invention to provide a log singulator which minimizes
the
amount of debris falling through gaps in the device.
It is a further object of this invention to provide a log singulator which
rapidly and
effectively singulates logs.
Other objects and advantages of the invention will be appreciated by reference
to
the following disclosure.
SUMMARY OF THE INVENTION
The invention comprises a singulator having a series of vertically overlapping
and
laterally offset support surfaces which reciprocate between one another
through the same
vertical plane. The support surfaces are continuous across the lateral extent
of the
singulator. The combined surfaces have the appearance of a single broad
staircase with
reciprocating steps.
Alternate support surfaces are connected together so as to create two sets of
support surfaces which move in unison. The two sets of support surfaces are
made to
reciprocate out of phase with one another by 180° such that when one
set of surfaces is at
the end of its forward stroke, the other set of surfaces is at the end of its
backward stroke.
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An abutment surface is provided on each support surface to promote logs toward
the next support surface during forward movement of the support surface. The
abutment
surface preferably extends from the forward edge of the support surface with
which it is
associated to terminate in close proximity to the support surface next below
it so as to
minimize the amount of debris that can be introduced between the support
surfaces or
between the abutment surface and the support surface below it.
The abutment surfaces of vertically adjacent support surfaces are
substantially
aligned when the support surfaces are at the ends of their respective strokes.
In another of its aspects, the invention comprises unscrambling and
singulating
apparatus for conveying logs from a first location in which a plurality of
unsingulated
logs are received to a second location to which singulated logs are delivered
one at a
time, comprising a plurality of parallel first planar support surfaces which
are
successively laterally offset in relation to one another and the planes of
which are
successively spaced in relation to one another, and the first planar surfaces
being
operatively connected to one another for simultaneous movement, a plurality of
parallel
second planar support surfaces which are successively laterally offset in
relation to one
another and the planes of which are successively spaced in relation to one
another, the
second planar support surfaces being operatively connected for simultaneous
movement,
a drive mechanism for reciprocating said first and second planar surfaces in
their
respective planes, such that the movement of the first planar surfaces is out
of phase with
the movement of the second planar surfaces by 180°, the first planar
surfaces being
interleaved with said second planar surfaces such that successive first and
second planar
surfaces vertically overlap one another and each planar surface reciprocates
between the
planes of the two vertically adjacent planar surfaces, and an abutment surface
associated
with each of the first and second planar surfaces for urging a log in the
direction of
movement of the planar surface.
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In another of its aspects, the invention comprises such apparatus wherein the
reciprocating movement of said first and second planar surfaces is such that
when any
one of said planar surfaces reaches the end of its forward stroke and the
immediately
adjacent planar surface below it is at the end of its backward stroke, the
abutment
surfaces associated with both support surfaces are substantially aligned with
one another.
In yet another of its aspects, the invention comprises such apparatus wherein
the
first and second planar surfaces are mounted on at least two vertical plates
and the drive
means comprises means for actuating movement of said plates.
Other aspects of the invention will become apparent from the detailed
description
of the preferred embodiment which follows and from the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
The preferred embodiment of the invention will be described by reference to
the
drawings in which:
Fig. 1 is a perspective view of the preferred embodiment of the invention in
which
the infeed is at the right and the outfeed is at the left of the figure;
Fig. 2 is a side elevation of the preferred embodiment of the invention, in
which
the infeed is at the left and the outfeed is at the right of the figure; and,
Figs. 3a, 3b, 3c, 3d and 3e are side elevations of the invention showing the
support
surfaces at successive stroke positions;
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DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to Fig. 1, the singulator 10 according to the invention delivers
logs from
an infeed location 12 where the logs are received in a scrambled and
unsingulated bundle,
to the outfeed 14 to which the device delivers unscrambled and singulated
logs.
A series of planar support surfaces 16a, 16b, 16c, 16d, and 18a, 18b, 18c, 18d
are
parallel to one another and are each continuous across the lateral extent of
the device (i.e.,
from side 20 to side 22). In the preferred embodiment, the planar support
surfaces are
formed plates. The formed plates may extend across the entire lateral extent
of the
device. Alternatively, each support surface may comprise a plurality of formed
plates
that are arranged side by side to span the lateral extent of the device, with
each end of
each plate being welded to the end of the adjacent plate and to underlying
support plates
(the support plates being described below) so as to effectively provide the
equivalent of a
continuous surface across the lateral extent of the device.
The planes of the support surfaces are successively offset in the vertical
plane as
between surfaces 16a and 18a and as indicated by the numeral 23. The support
surfaces
are also successively offset in the horizontal direction between the infeed
and the outfeed
as indicated by lines 24 and 26.
The offsets between successive support surfaces result in a step-like
configuration
extending from the infeed to the outfeed. The particular angles to the
vertical that are
formed by the planes of the support plates are not critical, provided the
overall stair-like
configuration extends from the infeed to the outfeed, and provided the support
surfaces
are parallel.
The planar support surfaces are arranged in two sets, the surfaces of one such
set
being identified by the numerals 16a to 16d and the surfaces of the other set
by the
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numerals 18a to 18d. Surfaces 16a to 16d are interconnected by vertically
oriented
support plates 28 which are best seen in Fig. 3a. One of the support plates 28
is also
visible in Fig. 1. Surfaces 18a to 18d are interconnected by vertically
oriented support
plates 30. Support plates 28 are parallel and spaced from support plates 30 to
enable
unobstructed movement of the plates along their parallel planes.
As is best appreciated by reference to Fig. 3a, abutment surfaces 32 are
provided
at the forward end of each support surface. Each abutment surface 32 extends
generally
toward the support surface which is next below it. In the preferred embodiment
the
abutment surface forms an angle of 90° in relation to its associated
support surface, but
the particular angle is not critical and need not be 90° provided the
abutment surface
extends generally in the direction of the support surface below it.
Each abutment surface 32 extends substantially up to and in close proximity to
the
support surface which is immediately below it. This serves to substantially
close any gap
between the adjacent surfaces and to minimize the amount of debris that can be
passed
between the two adjacent support surfaces or between the abutment surface and
the
support surface below it.
In the preferred embodiment, each support surface and its associated abutment
surface is integrally formed as single angled cap plate 34 which is mounted on
fingers 36
extending from the upper edges of the vertical plates 28 or 30 as the case may
be.
Support plates 28 are connected to one another by cross members 38 while
support
plates 30 are connected to one another by cross members 40. Movement of the
plates 28
and 30 is actuated by linkage arms 42, 44 which are attached either to the
cross members
38 or 40 or to plates 28 or 30 as the case may be.
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Each set of support plates is made to reciprocate in a rectilinear fashion.
The
reciprocating movement of the support surfaces 16 is out of phase by
180° with the
reciprocating movement of the support surfaces 18. Thus, when support surfaces
16 are
at the end of their forward stroke, support surfaces 18 are at the end of
their backward
stroke and vice versa. As this applies equally to all support surfaces, logs
can be
continuously and rapidly promoted toward the outfeed by being handed off from
one
support surface to the next as they reciprocate. As a log is pushed forward by
an
abutment surface and reaches the end of its forward stroke, the abutment
surface of the
next support surface will be aligned (since it will be at the end of its own
backward
stroke) and the log will fall to that support surface, to be immediately urged
forward on
the return (forward) stroke of the second support surface. This process is
repeated until
the log is discharged at the outfeed. Figs. 3a to 3e illustrate successive
positions of the
two sets of plates and the promotion of a log in the feed direction.
A proper phase angle of 180° between the reciprocating movements of
both sets of
support surfaces is achieved by attaching link arms 42, 44 to opposite ends of
a pivot
plate assembly 46 which is in turn actuated by a drive plate assembly and
crank arm 48.
The length of the support surfaces, their position on the vertical plates 28
or 30
and the length of the stroke they undergo should be chosen so that when one
support
surface is at the end of its forward stroke and the support surface below it
is at the end of
its backward stroke, the abutment surfaces associated with both support
surfaces are in
close proximity or substantially aligned, as indicated by the numeral 49 in
Fig. 3a. This
provide a nearly continuous surface for a log to fall from one support surface
to the next,
for example from support surface 51 to support surface 53. Such alignment need
not be
perfect. In the preferred embodiment, the upper-most abutment surface extends
between
half an inch and an inch beyond the lower abutment surface to ensure that logs
easily fall
to the support surface below. Similarly, the abutment surfaces need not
necessarily be
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parallel. However, they are preferably at least approximately parallel and a
properly
parallel arrangement is preferred.
The device is mounted on a frame 54 which includes wheel mounts 56 and 58.
Stroke wheels 60 and 62 are mounted in the wheel mounts and runner bars 64 and
66 are
secured to the support plates 28 and 30 to provide a surface on which to guide
and
support their reciprocating movement.
It will be appreciated by those skilled in the art that certain deviations
from the
preferred embodiment described herein may be practised and certain alterations
may be
made without departing from the scope of the invention.
