Traversing hoists – Having means to prevent or dampen load oscillations – Antisway
Reexamination Certificate
1999-04-01
2002-10-08
Brahan, Thomas J. (Department: 3652)
Traversing hoists
Having means to prevent or dampen load oscillations
Antisway
Reexamination Certificate
active
06460711
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a suspension type hoisting apparatus which has an elevating portion elevatably suspended from a base (for example, a carriage) via a suspension member and is able to suppress sway of the elevating portion in a short time.
2. Description of the Prior Art
There are many cases where a transfer apparatus, in which a suspension type hoisting apparatus (so-called crane) is incorporated, is frequently used as transfer equipment of loads in, for example, a factory. One example of such a transfer apparatus is illustrated in FIGS.
21
(
a
) and
21
(
b
).
The transfer apparatus AO, shown in FIGS.
21
(
a
) and
21
(
b
), is constructed and provided with a carriage
103
moving along a rail
102
disposed at the ceiling
101
, a suspension member
104
suspended from the carriage
103
, and an elevating portion
105
attached to the lower end portion of the suspension member
104
. A hand
105
a
which is able to hold an appointed load
106
is integrally attached to the elevating portion
105
. The suspension member
104
is wound and unwound by a winding device (not illustrated) which is attached to, for example, the carriage
103
side, whereby the elevating portion
105
is elevated and lowered.
When the load
106
is transferred by the transfer apparatus AO, first, as shown in FIG.
21
(
a
), the carriage
103
is stopped right above the load
106
, and the elevating portion
105
is lowered to cause the hand
105
a
to hold the load
106
. And, the elevating portion
105
is elevated to an appointed position with the load
106
held, and the elevating portion
105
is fixed at the carriage
103
, wherein the load
106
is transferred by the carriage
103
to a reference position along the rail
102
in a state shown in FIG.
21
(
b
). When the load
106
arrives at the reference position, the carriage
103
is positioned right above a placing position of the load
106
, and the load
106
is placed thereon by lowering the elevating portion
105
again.
By repeating the operations, loads can be efficiently carried or transferred, utilizing space in the vicinity of the ceiling, wherein there are comparatively few obstacles.
However, since the conventional transfer apparatus AO is constructed so that the elevating portion
105
is suspended by the suspension member
104
, the elevating portion
105
constitutes a pendulum, using the carriage
103
as a fulcrum. Therefore, for example, when the elevating portion
105
is elevated or lowered, sway occurs at the elevating portion
105
, which is responsive to inherent frequency determined by the length of the suspension member
104
. Therefore, in the conventional transfer apparatus AO, even though the carriage
103
reaches the reference position and causes the elevating portion
105
to be lowered, a load
106
can not be held by the hand
105
a
or a held load can not be placed by the hand
105
a
until the sway of the elevating portion
105
stops, wherein transfer efficiency is adversely influenced.
Furthermore, although a passive sway controlling device (for example, movement absorbing device, damper, etc.,) has been attached as a countermeasure, it is very cumbersome to adjust the sway controlling device, for example, in a case where the stop height of the elevating portion
105
differs.
SUMMARY OF THE INVENTION
The present invention was developed in view of the above-described drawbacks, and it is an object of present invention to provide a suspension type hoisting apparatus which is able to remarkably improve working efficiency by effectively stopping sway of the elevating portion.
In order to achieve the above-stated object, the present invention provides: a suspension type hoisting apparatus, which is able to adjust the position of an elevating portion elevatably suspended from the base via the suspension member by an elevating portion position controlling device, which is constructed and provided with a means for positioning a suspension member suspended from the base in the horizontal plane; a position controller for outputting a velocity reference signal on the basis of a deviation between a position reference signal and actual position with respect to the positioning means; and a velocity controller for outputting a force reference signal being a manipulated variable of the positioning means, on the basis of a deviation between the velocity reference signal outputted from the position controller for the positioning means and actual velocity, wherein, the elevating portion position controlling device includes a sway velocity detecting means for detecting a sway velocity of the elevating portion; a sway stop compensation portion for outputting a sway controlling signal for the positioning means on the basis of output from the sway velocity detecting means; and an adder portion for adding the sway controlling signal outputted from the sway stop compensation portion to an appointed signal on the control loop of the elevating portion position controlling device. Thereby, since it is possible to effectively stop sway of the elevating portion and to carry out positioning thereof by a simple control system, remarkable improvements in working efficiency can be secured.
Herein, the force reference signal outputted from the velocity controller, the velocity reference signal inputted into the velocity controller, or a position reference signal inputted into the position controller is considered as the appointed signal on the control loop of the elevating portion position controlling device, to which the sway controlling signal is added.
Furthermore, in a case where the base is constructed of a carriage, a moving means of the carriage may be used as the positioning means. However, in this case, the positioning direction is limited to the moving direction (for example, direction of a rail) of the carriage.
Furthermore, the sway stop compensation portion may be composed of a proportional element, for example, the value of which is established in compliance with a stop height of the elevating portion.
Still furthermore, in order to prevent a servo system from oscillating due to observation noise, it is preferable that a filter for eliminating such observation noise is attached to the sway stop compensating portion.
In a case where the sway velocity detecting means is composed so as to detect the relative sway velocity of the elevating portion with respect to the base, it is preferable that the sway velocity detecting means is further provided with a elastic vibration component detecting means for detecting elastic vibration components produced at the base, and an excluding means for influences due to the elastic vibration components from sway control made by the sway stop compensation portion on the basis of the elastic vibration components detected by the elastic vibration component detecting means.
Herein, the excluding means, for example, may be constructed so that it excludes influences, resulting from the elastic vibration components, from the sway control by adding elastic vibration compensating signals generated on the basis of the elastic vibration components detected by the elastic vibration component detecting means to the sway controlling signals outputted from the sway stop compensation portion. At this time, the elastic vibration compensating signal may be generated by a elastic vibration component compensation portion including a band pass filter to exclude noise components contained in the elastic vibration components detected by the elastic vibration component detecting means and a phase compensation portion for compensating a phase between the relative sway velocity of the elevating portion and the elastic vibration components.
Furthermore, the excluding means may be composed of a notch filter for suppressing the elastic vibration components from signals corresponding to the sway velocity of the elevating portion. In this case, a frequency band suppressed by the notch filter is adjusted on the basis of the elastic vibration components
Kato Kazumichi
Nakagawa Susumu
Sato Yuushi
Sugino Tsukasa
Yasuda Katsumi
Brahan Thomas J.
Shinko Electric Co. Ltd.
LandOfFree
Suspension type hoisting apparatus does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Suspension type hoisting apparatus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Suspension type hoisting apparatus will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2998347