Note: Descriptions are shown in the official language in which they were submitted.
V:~66
BACKGXOUND OF T~iE; INV~NTIOI~
(1) FIELD OF T~l~ INV~NrrION
The presen-t invention relates to a connec-ting device
f'or securing loads to a lifting or pulling rneans. The
device of the present in~ention is especially useful for
connecting log strops to a pulling rope, and will be
described with especial ref'erence to this application, bu-t
it will be apprecia-ted that the device of' the present
invention also may be used for connecting any of a wide
range of loads to pulling or lif'ting means.
(2) DESCRIPTION OF T~IE PRIOR ART
. .
Felled logs generally are dragged f'rom their fallen
position to a central pick-up or processing place by
attaching to each log a pulling rope or chain the other
~5 end of which is secured to a skidder or similar vehicle.
At present, the common method of' a~taching the pulling rope
to each log is to secure around the log a strop which
tightly encircles and grips the log. The free end of' this
strop is fi~ted with a metal ring, and the end of thé
pulling rope is secured to the ring by a shackel. Se~eral
rings may be secured to a single shackel.
This arrangement has two main drawbacks: firstt
the heavy loading on the shackel tends in time to distort
the shackel, making it difficult to fasten and unfasterl
the shackel pin; secondly, fastening and unfastening a
,.. ' ~
.
shackel pin is a time-cons~ning and f'iddling job,
especially if' the shackel is ca~ed with mud and the
threads of' the pin or pin socket f'ouled or dis-tor-ted.
U.S.Patent No.11~01503 (Williarn Brarnwell Smith)
discloses a fastener consisting of' a bar and link, which
is connec-ted by passing the bar through the link, and
then turning the bar through 90 so that the sides of -the
bar bear on the sides of'-the link and thus prevent the
bar from passing back through the link under load. This
-type of f`astener has been widely used f'or rnany years, and
is still in comrnon use f'or securing tyre chains.
Finnish Patent No.B~69L~1 (Oy Finnlines Ltd.) dis-
closes a f`astener or connector consisting of` a toggle and
a rectangular slot f'orrned in a U-bearn. The toggle is
shaped -to provide a rounded portion to which a tie-down
chain is attached, and an elongated end portion which is
longer than the slo-t. ln use, the toggle is passed
through the slot, and turned through 90 to allow the
elongated end portion to bear on the ends of the slot and
thus prevent the toggle f'rom passing back through the slot
under load.
The designs of' U.S.Patent No.lL~01503 and Finnish
Patent No.P469L~1 both have the drawback -that -the toggle
or bar must be manoeuvered manually through the slot or
link, and then manually turned -to the f'astening position.
Also, the ends of' the -toggle or bar must project a
~ 6 6
considerable distance beyond the ends of -the slot or link,
so that they cannot disengage accidentally, and this means
that the ends tend -to snag on debris and to pick up dirt.
An object of the present invention is the provision
of a connecting device which overcomes these disadvantages
and is quick and easy to use even in very dirty conditions.
BRIEF SUMMARY OF THE INVENTION
The present invention provides a connecting device
cornprising a ring having an internal diameter (a); and a
toggle which includes two legs inclined outwards from each
other, the closer ends of said legs being connected and the
other ends of said legs being spaced apar-t by a distance
(b) between the outer surfaces of said ends, measured in a
plane parallel to the plane of the ring when said ring and
toggle are engag~d under load in use, said distance (b)
being greater than said distance (a); and a cross-bar
extending between said legs and secured thereto such that
the distance (d) between the top of the -toggle and the
lower surface of the cross-bar is less than said distance
(a). Preferably, the toggle is substantially A-shaped :in
cross-section and the legs are of equal length.
BRIEF DESC~IPTION OF D~AWINGS
Figure 1 is a section through a connecting device in
accordance with a first embodiment of the invention;
Figures 2-4 are sectional views of the device of
_ ~,, _
Figure 1 showing the -three stages of' linking the toggle
to the ring in use; and
Figure 5 is a side view of' a second embodimen-t of th
invention.
DETAILED DESCRIPTIOr~ OF THE P F'ERHED ~r~BODIMENTS OF TH~
INVENTION
-
Referring to Figure 1, a connecting device 2 com-
prises a ring 3 having an internal diameter (a), and a
toggle 4.
The toggle 4 comprises a length of` steel rod bent to
form a V-shape in .cross-section with the outer surfaces of
the free ends of the legs 5 being spaced apart by a
distance (b) measured in a plane parallel to the plane of
the ring 3 when the ring and toggle are engaged under load
as shown in F'igure 1. The legs 5 are of substantially
equal length (c):- this is not essential, but there is no
advantage to be gained f'rom making them dif'ferent lengths,
and in f'act the toggle may be less easy to use if' one leg
is very much longer than the other. For the toggle -to
engage the ring in use, the distance (b) rnust be greater
than the internal diameter (a) of the ring 3.
The legs 5 are Joined and braced by a cross-bar 7,
which serves two functions:- it prevents the toggle from
becoming detached from the supporting link ~ oI' the pulling
chain (not shown) and it braces the legs 5 against -the
-- 5 --
.~.~i
compressive f'orces f set up when a pullinrr f'orce ~' is
applied to the toggle in use. To allow the toggle 4 to
drop through the ring 3 as hereina~'ter described, the
distance (d) between the lower surfac- o' the nd o the
cross-bar 7 and the top of the toggle must be less than
the internal diameter (a) of the ring.
The above-described connecting device is used as
follows: -the toggle 4 is secured to the last link g of
a pulling chain (or chain secured to a pulling rope),
either by welding the cross-bar 7 in place af-ter the legs
5 have been engaged with the link or by using a closea'ble
'blacksmith's link' f'or the last link ~. Another possibi-
lity is to form the cross-bar 7 with a central gap through
which the link ~ can be passed, after which the gap is
closed by weiding. The ring 3 is secured to the strop
(not shown) passing around the log to which the pulling
rope is to be connected. As shown in Figure 2, the
toggle is lowered onto the ring 3, allowing one of the legs
5 of the toggle to fall through the ring, and as it does
so, the ring engages the cross-bar 7 or the other leg 5,
tending to pivot the toggle into the position shown in
Figure 3, allowing the toggle to fall right through the
ring, as shown in Figure 4. The weight of' the toggle
makes it hang more-or-less vertical, as in Figure 4,
although it may hang asymmetrically if one of' the legs 5
is substantially longer or heavier than the other. The
-- 6 --
6~
free end of each leg/preferably is thickened (not shown)
or clad, to improve the wear resistance of the -toggle and
-to weight the ends of the leg and so -to assis-t the legs
to hang correc-tly~
When -the log is dragged by the pulling rope, the
toggle is drawn back towards the ring, i.e. to the position
shown in Figure 1. Once the toggle is completely through
the ring, it cannot accidentally be disengaged from -the
ring:- the only way in which the toggle can be disen-
gaged is for -the pulling force F to be removed, and the
toggle manually twisted from the position of Figure 4 to
that of Figure 3 and manoevered back through the ring.
If more than one log is to be skidded, the toggle
is inserted through the rings secured to the other log
strops in the same manner.
~ second embodiment of the invention is shown in
Figure 5. In this embodiment, the toggle 4 is formed
as a solid casting~ forging or pressing9 but the basic
features and proportions remain -the sarne as for the
embodiment of Figures 1-4 and are marked with the same
reference numerals and letters. The cross-bar 7 is
greatly increased in thickness, and the legs 5 may be
curved inwards, as shown, to aid the -toggle in seating
correctly in the ring in use.
The angle be-tween the legs 5 (-the mean angle, in
the case of the curved legs of Figure 5) may be varied if
.,
~0~6
desired, but i-t has been found that an optirnum angle is
in the region of` ~0. If the angle is rnuch less than this7
the legs 5 must be relatively long to achieve the correct
distance (b), and as mentioned above, very long legs make
the toggle inconvenient to use. However, if the angle is
much greater -than the optimum, it may be found necessary -to
increase the strength of -the toggle rnaterial because the
strength of the legs is reduced as the angle between them
is increased. For exarnple, the strength of legs a-t an
angle of 120 is approximately 0.6 of the strength of legs
at an angle of 50.
_ g _
~. .
