Field of the Invention
[0001] The present invention concerns a quick coupling for a tool, e.g. a digger or loading
bucket, and of the kind indicated in the preamble of claim 1.
Background of the Invention
[0002] Quick couplings of this kind are widely used for the purpose of rapidly and easily
changing between different implements, e.g. between diggers with different widths
or between digger and loading bucket. The quick coupling may include a manually operated
locking mechanism requiring that the machine operator leaves the operator's cabin,
or a remotely controlled locking mechanism that may be operated from the cabin and
which, for example, may comprise a hydraulic cylinder.
Object of the Invention
[0003] The invention has the object of providing an improved quick coupling for a digging
or loading machine of the kind mentioned in the introduction, and which by means of
simple measures enables achieving good function and extraordinary safety against unintended
release of the tool.
Description of the Invention
[0004] The quick coupling according to the invention is characterised in that it further
includes a safety lock adapted to provide an additional secure locking function between
the quick coupling and the connecting part of the tool. By means of simple technical
measures it is hereby possible to achieve good operation and an extraordinary good
safety against inadvertent release of the tool.
[0005] The quick coupling according to the invention is suitably designed such that the
safety lock is constituted by at least one, preferably hydraulic, locking cylinder
which is fastened to the quick coupling, and which includes a lock piston adapted
to interact with a complementary lock socket formed in the connecting part of the
tool.
[0006] The quick coupling according to the invention is preferably designed such that the
safety lock is constituted by a double acting hydraulic locking cylinder which is
fastened to the quick coupling, and which includes two lock pistons adapted to interact
with complementary lock sockets formed at each their side in the connecting part of
the tool.
[0007] With the object of minimising the built-in dimensions, the quick coupling according
to the invention may advantageously be designed such that the safety lock is constituted
by two joined hydraulic locking cylinders which are fastened to the quick coupling,
and which include two lock pistons adapted to interact with complementary lock sockets
formed at each their side in the connecting part of the tool.
[0008] The quick coupling according to the invention may particularly suitably be designed
such that the two joined locking cylinders are disposed side by side and designed
with a common inlet connection for hydraulic pressure liquid.
[0009] With the object of counteracting inadvertent returning of lock pistons by impact
against external obstacles, the quick coupling according to the application may advantageously
be designed such that at opposing outer sides and in the vicinity of the lock sockets,
the connecting part of the tool is provided with at least one projecting collar.
[0010] With the object of simplifying the connecting part at each their side of the tool,
the quick coupling may advantageously be designed such that the lock sockets are constituted
by elongated central lock holes that are formed in opposing sides of the connecting
part, and which extend substantially in parallel with a longitudinal edge part of
the connecting part. The connecting parts at each their side of the tool may hereby
be designed identical whereby production and storage are simplified as well.
[0011] With the object of enabling visual checking of the lock pistons by the machine operator,
the quick coupling according to the application may further be designed such that
at opposing outer sides and in the vicinity of the elongated lock holes, the connecting
part of the tool is provided with projecting collars along opposing sides of the lock
holes.
[0012] With the object of ensuring that the machine operator may visually supervise correct
locking engagement between lock pins and lock sockets, it may be suitable if the quick
coupling is designed such that the projecting collars are formed with outwardly bent
end parts.
Description of the Drawing
[0013] The invention is described more closely in the following with reference to the drawing,
on which:
- Fig. 1
- shows a plan view of an embodiment of quick coupling according to the invention, as
seen from one side thereof;
- Fig. 2
- shows a plan view of the quick coupling on Fig. 1, coupled to an embodiment of a connecting
part intended for being welded to a tool, e.g. a digger or a loading bucket, as seen
from the side;
- Fig. 3
- shows a plan view of the connecting part shown in Fig. 2;
- Fig. 4
- shows a plan view of the connecting part shown in Fig. 2, as seen from the top;
- Fig. 5
- shows a plan view of the quick coupling shown on Fig. 2, connected with the connecting
part - as seen from the top - with inactivated safety lock;
- Fig. 6
- shows a plan view of the quick coupling shown on Fig. 2, connected with the connecting
part - as seen from the top - with activated safety lock;
- Fig. 7
- shows a plan view of a preferred embodiment of a safety lock for a quick coupling
according to the invention, shown in inactivated condition;
- Fig. 8
- shows a plan view of a preferred embodiment of a safety lock for a quick coupling
according to the invention, shown in activated condition; and
- Fig. 9
- shows a plan view of another embodiment of a safety lock for a quick coupling according
to the invention, shown in activated condition.
Detailed Description of Embodiments of the Invention
[0014] The quick coupling 2 shown in Fig. 1 includes two parallel bearing plates 4 with
bearings 6, 8 provided for mounting the quick coupling 2 at steel plate support holders
4 projecting at an outer end of a digger or loading arm, or to connect a yoke for
a hydraulic cylinder for pivoting the quick coupling and the tool, respectively, e.g.
a digger or a loading bucket.
[0015] At one end, the quick coupling 2 is designed with hook-shaped coupling parts 10 which
are adapted to grip around a first transverse connecting rod 12 that extend between
plate-shaped connecting parts 14 (Figs. 3, 4) which at longitudinal edge parts 16
are adapted for being welded to a back side of the tool, e.g. a digger or a loading
bucket, with such spacing that the quick coupling 2 can be inserted between the connecting
parts 14 (Figs. 2, 5, 6).
[0016] At the opposite end of the quick coupling 2 there is formed two abutment surfaces
18 against which a second transverse connecting rod 20 is extending between the plate-shaped
connecting parts 14. When the connecting rod 20 bears against the abutment faces 18,
a hydraulic cylinder 22 is activated such that a hydraulic piston 24 displaces a double
lock wedge 26 to a position behind the connecting rod 20, such that the latter is
pressed against the abutment faces 18, whereby the connecting parts 14 and the tool
are securely connected to the quick coupling 2.
[0017] The quick coupling 2 is also provided with at least one safety lock which has the
task of establishing an extra mechanical connection between the connecting parts 14
and the quick coupling 2, why it is provided with a double acting safety lock 28 consisting
of two joined hydraulic locking cylinders 30, 32 with lock pistons 34, 36 and lock
pins 38, 40 (Figs. 7, 8). At a back side, the latter are both actuated by strong compression
springs 42, 44 that have the task of ensuring correct locking engagement between the
lock pins 38, 40 and lock sockets 46, 48 complementary therewith and formed in connection
with the connecting parts 14 - also in case of missing hydraulic liquid pressure.
[0018] In other words, the safety lock 28 is self-locking in such a way that locking engagement
is established by pressure relief of the hydraulic locking cylinders 30, 32, i.e.
the locking engagement is maintained if the hydraulic liquid pressure disappears,
or put in other words, a hydraulic liquid pressure has to be present in order to deactivate
the locking engagement.
[0019] As shown in Figs. 7 and 8, the safety lock 28 is preferably designed such that the
hydraulic locking cylinders 30, 32 are joined and disposed mutually off-set side by
side such that the total built-in length is minimised. Hereby may be achieved that
even relatively small quick couplings with less spacing between the bearing plates
4 may be equipped with safety locks according to the invention.
[0020] Fig. 9 shows an alternative design of a safety lock 50 with greater built-in length
and two lock pins 52, 54 arranged in continuation of each other, and which are operated
by a common, floatingly arranged, locking cylinder 56 with built-in compression spring
58.
[0021] As shown in Figs. 2-6, at opposing sides of the elongated central lock sockets 46,
48 there are mounted projecting collars 60, 62 having outwardly bent end parts 64,
66 that enables the machine operator to visually supervise correct locking engagement
of the lock pins 38, 40 with the connecting parts 14. The collars 60, 62 have the
primary task of preventing the lock pins 38, 40 from inadvertently being pressed back
and out of engagement with the connecting parts 14 in case that the quick coupling
2 hits an external obstacle by a lateral movement.
Reference numbers of the drawing
[0022]
2 quick coupling
4 bearing plates
6 bearings
8 bearings
10 hook-shaped coupling parts
12 first connecting rod
14 connecting parts
16 longitudinal edge parts
18 abutment surfaces
20 second connecting rod
22 hydraulic cylinder
24 hydraulic piston
26 double locking wedge
28 safety lock
30 locking cylinder
32 locking cylinder
34 locking piston
36 locking piston
38 lock pin
40 lock pin
42 compression spring
44 compression spring
46 lock socket
48 lock socket
50 safety lock
52 lock pin
54 lock pin
56 locking cylinder
58 compression spring
60 projecting collar
62 projecting collar
64 outwardly bent end parts
66 outwardly bent end parts
1. A quick coupling (2) for a tool, e.g. a dipper or a loading bucket, and including
connecting means adapted to be mounted at an outer end of a digger or loading arm,
the quick coupling (2) including coupling means for connecting the quick coupling
with complementing means of a connecting part (14) of the tool and a locking mechanism
with a displaceable locking wedge (26), which includes locking means adapted to interact
with the complementing coupling means (12, 20) of the connecting part (14) of the
tool, and which is adapted to displace by means of at least one, preferably hydraulic,
cylinder (22), as the coupling means are constituted by fixed hook-shaped coupling
members (10) that are adapted to interact with the connecting means (12) of the connecting
part (14) of the tool, and by coupling members adapted to fix the connecting means
(20) of the connecting part (14) of the tool when these abut on a contact face (18)
of the quick coupling (2), characterised in that it further includes a safety lock (28, 50) adapted to provide an additional secure
locking function between the quick coupling (2) and the connecting part (14) of the
tool.
2. A quick coupling (2) according to claim 1, characterised in that the safety lock (28) is constituted by at least one, preferably hydraulic, locking
cylinder which is fastened to the quick coupling, and which includes a lock piston
(34) with associated lock pin (38) adapted to interact with a complementary lock socket
(46) formed in the connecting part (14) of the tool.
3. A quick coupling (2) according to claim 1, characterised in that the safety lock (28) is constituted by double acting hydraulic locking cylinder (30,
32) which is fastened to the quick coupling, and which includes lock pistons (34,
36) with associated lock pins (38, 40) adapted to interact with complementary lock
sockets (46, 48) formed at each their side of the connecting part (14) of the tool.
4. A quick coupling (2) according to claim 1, characterised in that the safety lock (28) is constituted by joined hydraulic locking cylinders (30, 32)
fastened to the quick coupling, and which include lock pistons (34, 36) with associated
lock pins (38, 40) adapted to interact with complementary lock sockets (46, 48) formed
at each their side of the connecting part (14) of the tool.
5. A quick coupling (2) according to claim 4, characterised in that the two joined locking cylinders (30, 32) are disposed side by side and designed
with a common inlet connection for hydraulic pressure liquid.
6. A quick coupling (2) according any preceding claim with a complementary connecting
part (14) of the tool, characterised in that at opposing outer sides and in the vicinity of the lock sockets (46, 48), the connecting
part (14) is provided with at least one projecting collar (60, 62).
7. A quick coupling (2) according to claim 6, characterised in that the lock sockets (46, 48) are constituted by elongated central lock holes that are
formed in opposing sides of the connecting part (14), and which extend substantially
in parallel with a longitudinal edge part (16) of the connecting part (14).
8. A quick coupling (2) according to claim 6 and 7, characterised in that at opposing outer sides and in the vicinity of the elongated lock sockets (46, 48),
the connecting part (14) of the tool is provided with projecting collars (60, 62)
along opposing sides of the lock holes (46, 48).
9. A quick coupling (2) according to claim 6 and 7, characterised in that the projecting collars (60, 62) are designed with outwardly bent end parts (64, 66).