Spring devices – Resilient shock or vibration absorber
Reexamination Certificate
2000-03-01
2001-12-04
Butler, Douglas C. (Department: 3613)
Spring devices
Resilient shock or vibration absorber
C296S019000, C188S300000
Reexamination Certificate
active
06325363
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to a vibration isolator for use in, for example, an ambulance for carrying sick or wounded people and, in particular but not exclusively, to a locking mechanism for such a vibration isolator.
2. Description of the Related Art
A vibration isolator on which a stretcher is to be placed includes a vibration isolating mechanism employing, for example, an electrically-operated air suspension system. This system performs level adjustment according to the load (the weight of a sick or wounded person) and absorbs vibration inputted from a vehicle floor using an air spring, thereby lightening a burden applied to the sick or wounded person on the stretcher.
If the sick or wounded person must have a heart massage or the like, the vibration isolator is locked so as not to operate, thus preventing a force applied to the sick or wounded person from escaping.
Recently, a vibration isolator that employs a magneto-spring to improve the riding comfort has been proposed. The vibration isolator proposed by the applicant of this application is of a construction in which a movable frame is allowed to freely rock in the vertical direction and in the longitudinal direction of the vehicle with respect to the vehicle floor.
Accordingly, a locking device for this kind of vibration isolator is required to suppress both the vertical movement and the longitudinal movement of the movable frame. The use of conventional locking devices may give rise to incomplete locking.
SUMMARY OF THE INVENTION
The present invention has been developed to overcome the above-described disadvantages.
It is accordingly an objective of the present invention to provide a reliable locking mechanism for a vibration isolator capable of positively locking, with a simple operation, a movable frame that is allowed to rock with respect to a vehicle floor, regardless of the position of the movable frame.
In accomplishing the above and other objectives, the locking mechanism according to the present invention includes a stationary portion and a movable portion mounted on the stationary portion so as to undergo a rocking motion at least in a vertical direction. The locking mechanism also includes first and second lock pins movable between a locking position and a locking release position, a link mechanism connected to the first and second lock pins, and an operation knob movable between the locking position and the locking release position for operating the first and second lock pins via the link mechanism. When the operation knob is moved from the locking release position to the locking position, the link mechanism moves the first and second lock pins toward each other to sandwich a portion of the stationary portion therebetween, thereby locking the movable portion with respect to the stationary portion.
By this construction, it is possible to positively lock the movable frame with a simple operation.
Advantageously, the stationary portion has an opening defined therein. In this case, the first lock pin is positioned outside the stationary portion, while the second lock pin is positioned within the opening. By so doing, a portion of the stationary portion can be easily sandwiched between the first and second lock pins during locking, making it possible to achieve reliable locking, regardless of the position of the movable portion.
Furthermore, the stationary portion has a first depression formed at an outer periphery thereof and a second depression formed at a portion of the opening so as to confront the first depression. When the operation knob is at the locking position, the first and second lock pins are received in the first and second depressions, respectively. This construction can prevent not only a vertical movement of the movable frame but also a longitudinal movement of the movable frame.
Conveniently, the movable portion comprises a lock pin guide member having first and second guide grooves defined therein, in which the first and second lock pins are loosely inserted so as to move along the first and second guide grooves, respectively. By so doing, the operation of the first and second lock pins is ensured, resulting in a highly reliable lock mechanism.
REFERENCES:
patent: 3630565 (1971-12-01), Lehmann et al.
patent: 1033123 (2000-09-01), None
patent: 8206169 (1996-08-01), None
patent: 10166806 (1998-06-01), None
patent: 245774 (2000-09-01), None
Patent Abstracts of Japan, vol. 1996, No. 10, Oct. 31, 1996 (1996-10-31) & JP 08 154781 A (Delta Kogyo Co Ltd), Jun. 18, 1966 (1996-06-18) *abstract*.
Butler Douglas C.
Delta Tooling Co., Ltd.
Wenderoth , Lind & Ponack, L.L.P.
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