Automatic balancing apparatus for balancing stand

Details Automatic balancing apparatus for balancing stand Automatic balancing apparatus for balancing stand

1999-07-29

2001-02-13

Marmor, Charles A. (Department: 3681)

Machine element or mechanism

Control lever and linkage systems

Multiple controlling elements for single controlled element

C248S123200, C033S366001, C340S689000, C901S048000, C901S049000

Reexamination Certificate

active

06186023

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an automatic balancing apparatus for a balancing stand, which suspends and supports weights.
2. Description of the Prior Art
There conventionally exist balancing stands which suspend and support weights in optional positions in the air. For example, balancing stands capable of holding weights such as an operation microscope and auxiliary devices are used in the medical field (e.g. an Official Gazette of Japanese Patent Application Laid-open (kokai) No. 269463-1994). Balancing stands of the type generally have a structure in which a parallel linkage mechanism formed by a combination of a plurality of vertical arms and horizontal arms is supported at a predetermined fulcrum, an operation microscope and/or auxiliary devices is/are held at one end of the parallel linkage mechanism, and a counterweight is provided at the other end of the mechanism for balancing the weight relative to the operation microscope, etc.
A location of the balancing stand is selected to an optimum position according to the content of the operation to be performed, and balance adjustment is effected there. Since the auxiliary devices such as a side scope for an assistant doctor and a video camera are secured to the operation microscope, adjustment of whole balance is made by displacing the positions of the counterweight manually in accordance with the weight of the auxiliary devices.
However, positional adjustment of a counterweight has been made manually in a structural sense in the earlier technologies, so that balancing adjustment has not been effected so promptly. Further, since the parallel linkage mechanism moves to a large degree in unbalanced conditions, there is a possibility that the linkage mechanism may strike against some apparatus or the like present nearby. Under the circumstances, proposals of automatic balancing apparatuses applicable to the balancing stand of this kind have been waited. More specifically, proposals of automatic balancing apparatuses having a compact structure and applicable to the conventional balancing stands have been especially waited.
The present invention was accomplished in view of the earlier technologies, and its object is to provide an automatic balancing apparatus having a compact structure, capable of adjusting balance in an automatic and essentially prompt manner, and preventing arms from moving so substantially in unbalanced conditions.
SUMMARY OF THE INVENTION
In order to achieve the above object, an automatic balancing apparatus for a balancing stand according to the present invention is comprised of: a vertical arm and a horizontal arm mounted to a joint fulcrum in a pivotal manner and the joint fulcrum is fixed to either the vertical arm or a horizontal arm; weights being weighed to an end side of the horizontal arm; a counterweight for balancing with respect to the weights being weighed to the other end side; a detecting mechanism for detecting unbalanced conditions of the horizontal arm; and a driving mechanism for displacing the counterweight in a balancing direction in response to signals outputted by the detecting mechanism, and the detecting mechanism is provided with: a gear fixed to the joint fulcrum; a lever pivotally supported at a middle portion thereof on the vertical arm or horizontal arm whichever not being integrally fixed to the gear and the lever is further provided with at one end thereof a telescopic latch engageable with and detachable from the gear; a pair of stoppers opposed to each other with a predetermined clearance with the other end of the lever being sandwiched between the stoppers; urging means for holding the other end of the lever at a neutral position of the clearance; and a pair of switches provided opposed each other with the other end of the lever interposed therebetween and the switches is pushed by the other end of the lever.
In another invention, the automatic balancing apparatus for a balancing stand may be provided with a configuration in which a parallel linkage mechanism formed with a combination of a plurality of vertical arms and horizontal arms is supported at a predetermined fulcrum, and a detecting mechanism is provided on a joint fulcrum on which mounted are a set of a vertical arm and a horizontal arm of the parallel linkage mechanism.
According to the invention, a latch provided at a distal end of a lever is urged to engage with a gear fixed at a joint fulcrum jointing a vertical arm and a horizontal arm, for effecting angular displacement, thereby actuating a switch for a detecting mechanism. Because the mechanism is compact, it is easily applicable to existing balancing stands in which for example a parallel linkage mechanism formed with a combination of a plurality of vertical arms and horizontal arms is supported at a predetermined fulcrum. Signals are transmitted from the actuated switch to a driving mechanism to move the counterweight automatically in a balancing direction for effecting balancing adjustment, so that time as required for an adjustment operation can be reduced and unskilled operators can perform an adjustment operation easily. The detecting mechanism is further provided with a pair of stoppers combined with a lever for preventing the horizontal arm and a parallel linkage mechanism interlocking therewith from moving so substantially beyond abutment of the stoppers against the lever in unbalanced conditions, thereby there is no danger that the horizontal arm may strike against persons or equipment present nearby. Thus, physical engagement between the stoppers and the other end of the lever forcedly prevents the horizontal arm from rotating further in a structural sense. Accordingly, if an electrical failure should happen to the switches or the like, any substantial movement of the horizontal arm caused by unbalance in weight will be completely prevented and with the result of that, the present apparatus is advantageous in an aspect of safety.
The present invention is not limited to the above description, and other objects, advantages, features and uses of the invention will be apparent from the following description taken in conjunction with the accompanying drawings, and it is to be understood any appropriate changes and modifications made without departing from the spirit or scope of the invention fall within the scope of the invention.


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Patent Abstracts of Japan, Nakamura Masakazu, Medical Stand Device, Oct. 13, 1998.

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