Note: Descriptions are shown in the official language in which they were submitted.
CA 02223802 1999-OS-07
GRAPPLE
The present invention relates to a grapple for Lifting logs or similar
materials which includes a pair of squeeze plates for locating the ends of the
logs.
Grapples for lifting logs and similar elements are well known and
generally comprise a boom mounted on a suitable transportation vehicle with a
swivel coupling at the end of the boom which carries a mounting head for
swivelling
movement around a vertical axis at the end of the boom. On the mounting head
is
carried a pair of upstanding parallel plates each on a respective side of the
swivel
and between the plates is a pair of grapple jaws with each jaw having a pivot
mounting at its upper inner end. The jaws are driven by suitable hydraulic
mechanisms so that depending outer end can be moved inwardly and outwardly to
engage around a collection of logs or other equipment to be lifted.
The grapple is often used in logging for lifting logs onto a trailer for
transportation and generally the logs are of the same or similar length with
the
intention that they be loaded in parallel arrangement with the ends at the
sides of the
trailer.
Various techniques are used for locating the ends so that they are
substantially coplanar standing in vertical planes at the side of the vehicle.
Some
logs are difficult to load in this way and that they are particularly slippery
and tend to
twist within the grapple jaws and poplar is one example of logs which are
difficult to
load in this way.
It is one object of the present invention to provide an improved grapple
for lifting logs which allows better control of the logs while they are being
lifted and
particularly slippery logs such as poplar which can be difficult to control.
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According to a first aspect of the invention, therefore, there is provided
a grapple comprising:
a central mounting member for attachment to a swivel mount of a
boom;
a pair of grapple jaws pivotally connected to and depending from the
mounting member, each for pivotal movement about a respective one of a pair of
parallel generally horizontal pivot axes such that the jaws can move from an
open
position toward each other into a closed position for grasping a plurality of
logs for
lifting;
and a pair of end engagement plates for engaging and locating ends of
the logs when grasped for lifting, the plates defining inwardly facing
parallel surfaces
arranged substantially at right angles to the axes;
the mounting member including a pair of horizontal parallel mounting
beams located each on a respective side of the swivel mount and parallel to
the
pivot axes;
the end engagement plates being mounted on the mounting member
at a respective end of the mounting beams for movement relative to the
mounting
member in a direction at right angles to the surfaces so as to decrease the
distance
between the surfaces for squeezing the log ends.
Preferably the end engagement plates are mounted for movement
vertically relative to the mounting beams in a direction at right angles to
the beams.
Preferably the end engagement plates are mounted on the mounting
beams for free independent sliding movement in the vertical direction.
Preferably each mounting beam includes a pair of slide portions for
movement longitudinally thereof for moving the end engagement plates at right
angles to the surfaces.
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Preferably each slide portion has a sleeve at an end thereof at right
angles to the beam and receiving a vertical rail of the end engagement plate
for
sliding movement therealong in a direction at right angles to the beams.
Preferably the vertical rail is mounted at a position on the end
engagement plate spaced inwardly from the sides thereof.
Preferably the vertical rail is mounted on the respective end
engagement plate between top and bottom horizontal rails thereof.
Preferably the mounting beams are welded to a pair of grapple
mounting plates at right angle to the beams, each grapple mounting plate being
located on a respective side of the grapple jaws and carrying the grapple jaws
therebetween for said pivotal movement relative thereto.
Preferably the grapple mounting plates extend above the mounting
beams with the beams passing therethrough.
According to a second aspect of the invention there is provided a
grapple comprising:
a central mounting member for attachment to a swivel mount of a
boom;
a pair of grapple jaws pivotally connected to and depending from the
mounting member, each for pivotal movement about a respective one of a pair of
parallel generally horizontal pivot axes such that the jaws can move from an
open
position toward each other into a closed position for grasping a plurality of
logs for
lifting;
and a pair of substantially vertical end engagement plates for engaging
and locating ends of the logs when grasped for lifting, the plates defining
inwardly
facing parallel surfaces arranged substantially at right angles to the axes;
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the mounting member including a rigid support structure for supporting
the end engagement plates;
the rigid support structure being actuable for effecting substantially
horizontal movement of the end engagement plates relative to the mounting
member
inwardly and outwardly in a direction at right angles to the surfaces so as to
decrease and increase the distance between the surfaces for squeezing and
releasing the log ends;
the rigid support structure supporting the end engagement plates for
guided movement in a substantially vertical direction parallel to the
surfaces.
Preferably the end engagement plates are mounted on the rigid
support structure for free independent sliding movement in the vertical
direction.
One embodiment of the invention will now be described in conjunction
with the accompanying drawings in which:
Figure 1 is an isometric view of one half only of a grapple according to
the present invention.
Figure 2 is a side elevational view of the grapple of Figure 1.
Figure 3 is a top plan view of the grapple of Figure 1 with the swivel
mounting omitted for convenience of illustration.
In the drawings like characters of reference indicate corresponding
parts in the different figures.
A grapple includes a swivel mounting generally indicated at 10 which is
arranged for attachment to a boom (not shown) of a suitable transportation
vehicle.
The swivel mounting includes a pair of drive motors 11 which operate twisting
movement of the swivel so that a support plate 12 of a mounting member of the
CA 02223802 1999-OS-07
grapple can twist relative to the boom about a vertical axis to effect
adjustment of the
orientation of the grapple jaws of the grapple. The mounting plate 12 is
attached to
a pair of upstanding parallel grapple plates 13 and 14 which are arranged each
on a
respective side of the swivel 10.
5 The grapple jaws are indicated at 15 and 16 respectively and each
comprises a pair of arcuate side plates 17 and 18 and a transverse jaw plate
19. At
the upper inner end, each side plate 17) 18 is arranged to lie just inside and
parallel
to a respective one of the grapple plates 13 and 14. A pivot pin 20 provides a
pivotal
movement of the grapple jaw about a pivot axis passing through the aligned
pivot
pins 20 with an axis at being at right angles to the grapple plates 13 and 14.
The
side plates 17 and 18 and the grapple plate 19 converge to an apex 21 which
depends downwardly from the pivot pin 20 and that apex defines in effect an
edge of
the grapple jaw with the apexes of the two grapple jaws moved inwardly and
outwardly by the pivotal movement around the pivot axes of the grapple jaws.
Actuation of the movement of the grapple jaws is effected by a pair of
cylinders 22
which extend from a bracket 23 on a side of the mounting plate 12 to a bracket
24
on the back of the grapple plate 19.
A pair of mounting beams 25 and 26 extend through an upper part of
the grapple plates 13 and 14 at right angles thereto and are welded to the
grapple
plates so as to be fixed in position thereon. Each beam 25 therefore has a
respective end 25A, 25B extending outwardly beyond an outer side of the
respective
grapple plate 13; 14. At each end of the beam 25, 26 are provided a slide
portion
30, 31 which can slide inwardly and outwardly inside the beam with an outside
surface of the slide portion forming a sliding fit on the interior of the
beam. At each
outer end of the slide portion 30, 31 is provided a bracket 32 defining a
vertical
sleeve 33. Thus the two beams provide four vertical sleeves arranged in pairs
with
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each pair on a respective side of the grapple plates. The beams carry a pair
of end
engagement plates 40 and 41 each mounted respectively on a pair of the sleeves
33. Each engagement plate comprises an inner sheet metal plate 42 which is
supported by a plurality of flanges 43, 44, 45, 46, 47 and 48 at spaced
positions
across the plate so as to provide a rigid structure for the plate. The flanges
are
welded to a top rail 49 and a bottom rail 50 also attached to the sheet metal
plate 42.
The plate 42 thus defines an inwardly facing surface for engaging the ends of
the
logs.
Between the flanges 44 and 45 and between the flanges 46 and 47 is
welded a vertical rail 51, 52 which is shaped to fit inside a respective one
of the
sleeves 33. The rail 51, 52 is free and exposed between the top and bottom
rails 49
and 50 and therefore the sleeve can slide upwardly and downwardly relative to
the
rail along the full length of the rail.
Each engagement plate 40, 41 is therefore free to slide vertically
upwardly and downwardly relative to the beams. No power is provided for this
sliding movement but instead the plate is free to slide upwardly and
downwardly if
engaged at the bottom and pushed upwardly. Inward and outward driving
movement of the slide portions 30 and 31 is effected by a pair of drive
cylinders 60
and 61 connected between brackets 62 on the respective grapple plate and 63 on
the engagement plate.
The grapple plates 13 and 14 are arranged so that they are increased
in width and thus extend outwardly to the sides of the pivot pins 20 in load
portions
above the pivot pins 20 with a top surface of the grapple plate arranged above
the
beams. The grapple plate therefore forms a relatively wide upper portion
sufficient
to receive the beams therethrough with the beams being spaced sufficiently to
allow
the position of the swivel mount 10 between the beams.
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In use, the cylinders 60 and 61 are actuated to move the engagement
plates to a fully extended position spaced outwardly from the grapple jaws.
The
boom is then actuated to move the grapple to a position for lifting a
plurality of logs
with the logs extending parallel to the pivot axes of the grapple jaws. The
grapple
jaws are then actuated to move inwardly to grasp the logs. As the grapple jaws
are
moved to the required position, in the event that the bottom rails 50 engage
the
ground or other element in the area, the engagement plate is thus pushed
upwardly
so it slides along the sleeves 33 to whatever position it reaches when pushed
by the
downward movement of the grapple. The engagement plates 40 and 41 are then
moved inwardly by actuation of the cylinder 60 and 61 so that the inside
surface of
the plate 42 engages the ends of the logs to push the logs into a coextensive
position and to assist in supporting the logs by holding the ends. The logs
are thus
prevented from slipping and twisting and moving longitudinally so that all of
the logs
are held in position for effective transportation by the grapple to a suitable
location
such as a loading trailer.
Since various modifications can be made in my invention as herein
above described, and many apparently widely different embodiments of same made
within the spirit and scope of the claims without departing from such spirit
and
scope, it is intended that all matter contained in the accompanying
specification shall
be interpreted as illustrative only and not in a limiting sense.
