Handling: hand and hoist-line implements – Grapple – Pivoted jaws
Reexamination Certificate
1997-11-12
2001-07-03
Cherry, Johnny D (Department: 3652)
Handling: hand and hoist-line implements
Grapple
Pivoted jaws
C294S081610, C294S097000, C294S118000
Reexamination Certificate
active
06254157
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a load lifting apparatus suitable for use in a materials-handling operation, which enables loads (particularly, heavy objects) of various shapes and structures to be readily clamped and allows the loads to be readily released at a desired position after they have been lifted and moved thereto.
To lift and move to a desired position a heavy load, e.g. a concrete block or pipe or a steel pipe, the following method has heretofore been employed: A wire rope or chain is wound around the load, and the other end of the wire rope or chain is engaged with a hook or the like of materials-handling equipment. In this state, the load is lifted and moved to the desired position, and then the wire rope or chain is removed from the load.
Some loads are lifted and moved to a desired position as follows: Engagement members, e.g. bolts or hooks, for engaging a wire rope or chain have previously been attached to the loads, or the loads have been arranged such that these engagement members can be attached thereto. In a materials-handling operation, a wire rope or chain is engaged with engagement members previously attached to a load or engagement members attached thereto at the site of work, and the other end of the wire rope or chain is engaged with a hook of materials-handling equipment. After the load has been lifted and moved to a desired position, the wire rope or chain is disengaged from the engagement members attached to the load.
Materials-handling equipment, e.g. a crane, has a lifting apparatus that has clamping members for clamping a load as an object to be lifted. The clamping members of the lifting apparatus are opened by human power or using a jig, e.g. a hydraulic device, to pick up a load to be lifted. Then, the load is lifted and moved to a desired position by the materials-handling equipment. At the destination, the clamping members are removed from the load by human power or using a jig, e.g. a hydraulic device.
The above-described conventional method in which a wire rope or chain is wound around a load or engaged with engagement members by a manual operation suffers from the problem that the materials-handling operation is difficult because it is carried out by a manual operation and, at the same time, it is dangerous at a shaky work site.
The conventional method in which the clamping members of materials-handling equipment are operated by human power or using a jig, e.g. a hydraulic device, suffers from the problem that it is difficult to operate the clamping members at a job site and, at the same time, the use of a hydraulic device or other similar jig involves a mechanical failure and causes the overall size of the equipment to increase.
If such a jig as a hydraulic device is mounted on a vehicle or the like, it occupies an installation space, resulting in a reduction of the space for loading an object to be lifted, and also causing the cost of the equipment to increase.
SUMMARY OF THE INVENTION
In view of the above-described circumstances, an object of the present invention is to provide a load lifting apparatus suitable for use in a materials-handling operation, which enables loads of various shapes and structures, e.g. concrete products, to be clamped by a one-touch simple operation despite an extremely simple structure and allows the loads to be released by a one-touch simple operation at desired places after they have been lifted and moved thereto.
To solve the above-described problem, the present invention provides a load clamping and lifting apparatus including a link mechanism (
14
) in which a pair of clamping members (
1
and
2
) and a plurality of members (
4
,
5
,
8
,
8
-
1
,
8
-
2
) are supported by a plurality of pivot shafts. The upper part of the link mechanism (
14
) is arranged to be capable of being lifted and lowered by a lifting device. The clamping members (
1
and
2
) rotate about a pivot shaft (
3
or
3
′) in response to vertical extension and contraction of the link mechanism (
14
), thereby enabling an object (
11
) to be grasped by the distal end portions of the clamping members (
1
and
2
) directly or indirectly through grab members (
10
) by the extension of the link mechanism (
14
), and allowing the object (
11
) to be released therefrom by the contraction of the link mechanism (
14
). The load clamping and lifting apparatus has a lock-unlock mechanism (
20
,
30
,
40
,
50
,
60
, or
70
) that is actuated in response to the vertical extension and contraction of the link mechanism (
14
), which is caused by vertical movement of the lifting device, to lock the clamping members in respective predetermined positions of rotation about the pivot shaft and to unlock the clamping members in response to the vertical movement of the lifting device.
In the load clamping and lifting apparatus, the lock-unlock mechanism (
20
,
30
, or
40
) has a frame (
21
,
31
, or
41
) provided with a guide groove; a latch (
24
,
34
, or
44
); and a shunting member (
23
,
33
, or
43
). The frame (
21
,
31
, or
41
) is attached to a clamping member (
1
or
2
) or other member (
4
or
5
) constituting the link mechanism (
14
) or to a member (
8
,
8
-
1
, or
8
-
2
) that moves in response to extension and contraction of the link mechanism. The guide groove (
22
,
32
, or
42
) is pierced with a projecting pin (
15
) provided on a clamping member (
1
or
2
) or other member (
4
or
5
) constituting the link mechanism (
14
) or on a member (
8
,
8
-
1
, or
8
-
2
) that moves in response to extension and contraction of the link mechanism. The projecting pin (
15
) is movable in the guide groove (
22
,
32
, or
42
). The latch (
24
,
34
, or
44
) and the shunting member (
23
,
33
, or
43
) are rotatably supported on the frame (
21
,
31
, or
41
) by respective pivot shafts (pins
25
,
35
, or
45
;
27
,
37
, or
47
) such that the distal ends of the latch and the shunting member project into the guide groove (
22
,
32
, or
42
) so that the latch and shunting member are each rotated by movement of the projecting pin (
15
) in one direction, and rotation of the latch and shunting member caused by movement of the projecting pin (
15
) in the opposite direction is limited by respective limiting devices (stopper pin
26
,
36
, or
46
; pin
27
,
37
, or
47
). The guide groove (
22
,
32
, or
42
) is formed such that after the projecting pin (
15
) has moved in one direction past the latch (
24
,
34
, or
44
), movement of the projecting pin (
15
) in the opposite direction is limited by the latch (
24
,
34
, or
44
), and when the projecting pin (
15
) moves in the opposite direction after moving in the one direction by a predetermined distance past the shunting member (
23
,
33
, or
43
), the shunting member (
23
,
33
, or
43
) enables the projecting pin (
15
) to bypass the latch (
24
,
34
, or
44
) and to move in the opposite direction (see
FIGS. 2
,
4
and
6
).
In the load clamping and lifting apparatus, the lock-unlock mechanism (
50
) has a frame (
51
) provided with a guide groove (
52
); a latch projection (
54
) integrally formed with the frame (
51
) such that the latch projection (
54
) projects into the guide groove (
52
); and a shunting member (
53
). The frame (
51
) is attached to a clamping member (
1
or
2
) or other member (
4
or
5
) constituting the link mechanism (
14
) or to a member (
8
,
8
-
1
, or
8
-
2
) that moves in response to extension and contraction of the link mechanism. The guide groove (
52
) is pierced with a projecting pin (
15
) provided on a clamping member (
1
or
2
) or other member (
4
or
5
) constituting the link mechanism (
14
) or on a member (
8
,
8
-
1
, or
8
-
2
) that moves in response to extension and contraction of the link mechanism. The projecting pin (
15
) is movable in the guide groove (
52
). The shunting member (
53
) is rotatably supported on the frame (
51
) by a pivot shaft (pin
57
) such that the distal end of the shunting member (
53
) projects into the guide groove (
52
) so that the sh
Armstrong Westerman Hattori McLeland & Naughton LLP
Cherry Johnny D
Notsuunso Kabushikikaisha
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