JPH0424582B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to elevators, and more particularly to shock absorbers for elevators.

Problems to be Solved by the Invention Hydraulic buffers are used in elevators to reduce the speed of the elevator car or counterweight under certain conditions. A typical hydraulic shock absorber has a heavy liquid container and a piston extending into the container to push the liquid through a port. This fluid flow causes a gradual deceleration, with the deceleration pattern determined by the position of the port along the direction of piston movement.

All conventional elevator dampers of this type prevent the ingress of foreign matter such as dust (which can wear the piston and sealing surfaces during damping, e.g. during performance service inspections), and To prevent the resulting air/liquid mixture from escaping, a piston seal is used to seal the gap around the piston rod and container. Additionally, the external seal deteriorates over time and can sometimes become brittle. The service life of a shock absorber is largely determined by the effectiveness of these piston seals in preventing the ingress of foreign matter and preventing fluid leakage.

Primarily because of the seals, currently commercially available buffers are relatively expensive to manufacture, expensive and difficult to maintain, and require periodic maintenance to inspect the seals.

The primary objective of the invention is to provide a very inexpensive buffer that does not require inspection or servicing of the seals.

Means for Solving the Problems A hydraulic shock absorber according to the invention extends through a sleeve on top of a partially filled liquid (oil) container into an internal cylinder that is also partially filled. It has a piston (plunger). When the piston is depressed, hydraulic oil is forced out of the cylinder and the liquid level rises, creating a liquid/air mixture in the container. This mixture is forced (by the action of the piston) through a liquid separator (eg, a narrow passage) surrounding the piston at the top of the container, separating the liquid and air within the mixture. The liquid falls and is directed (e.g., funneled) to the piston, lubricating it as it descends. Air is forced out of the container through the sleeve, removing dirt and other foreign matter from the gap between the piston and the sleeve. Because of this structure,
No seals are required to clean the piston or to prevent liquid from leaking from the container.

Accordingly, the present invention provides a buffer with a number of features. Buffers do not have seals of any kind, can be made of all metal parts, and require no maintenance. Foreign matter is removed from the gap around the piston by test operation of the buffer. You can easily check the fluid level without using a dipstick by simply opening the port and looking inside. If the liquid is not visible, the liquid is below the minimum limit, and if it is visible, the liquid is at least the minimum limit and not over the maximum limit (ie, within the safe range).

A feature of the invention is that it does not require the use of fasteners of any kind, making the buffer easier and cheaper to manufacture as a single assembly with all parts permanently attached (i.e., welded). It is possible.

The invention therefore provides a very simple, inexpensive and truly maintenance-free buffer.

EXAMPLE Referring to FIG. 1, a buffer 10 according to the present invention
has a piston 12 (or rod) extending into the container 16 through a sleeve 16a. Inside this container 16 there is an internal cylinder 18, which is, as it were, a piston 12.
to guide the piston 12 as it enters and exits the buffer 10. The piston has a slightly raised, chamfered section 12a which serves as a stop when the piston rests on the sleeve section 16c. The sleeve fits fairly tightly around the piston to provide a good metal-to-metal seal. Similarly, the piston 12 slides tightly within the inner cylinder 18. cylinder 1
8 forms a first chamber 19a, a second chamber 19b on its exterior, and a gathering area 19c on its upper part. The two chambers are partially filled with liquid (oil). cylinder 1
At the upper end of 8 there is a small annular passage 19d (this will be explained below) which separates the chamber 19b and the area 19c and serves as a nozzle to separate the liquid (oil) and the air.
is around the piston.

The ratio of the height and width of the passage (along the circumference of the cylinder 18) is 0.013. The ratio of the flow area to the passage area upstream (downward) of the passage is 120, and the ratio of the passage area to the area downstream (near the piston) is 13. The passage thus acts as a nozzle.
In addition, the gap between the piston and the sleeve constitutes a downstream second nozzle through which air can escape from the container due to internal pressure, and which air must flow from the first nozzle. Therefore, clean the gap in the second nozzle as explained below.

The piston 12 is provided with ring-shaped cuts 12b along its lower end, which act as a dynamic seal without the use of rings. This is because within those seals, hydraulic oil is evenly distributed around the piston under uniform pressure, helping to align the piston and lubricating the piston as it moves within the cylinder 18. It is.
(Alternatively, a single metal piston ring may be used in the groove furthest from the piston face to restrict flow through the piston.) In accordance with conventional techniques, cylinder 18 is immersed in fluid 20. Ports 18a are provided along the longitudinal section within the piston area through which liquid is forced from chamber 19a to chamber 19b as the piston descends. On the downward stroke, the number of remaining ports decreases. (This is not shown), this results in a reduced flow area and an increased resistance to liquid flow as the piston moves down within the cylinder. At the same time, the speed of the piston decreases because the elevator is decelerated and the flow rate of liquid through the port area is correspondingly reduced. Therefore, the damper stopping force remains approximately constant with respect to piston displacement, so that the elevator is decelerated approximately uniformly. At the top of the piston between the cylinder 18 and the backing plate 24,
A spring 22 is arranged surrounding the piston 12. The spring 22 biases the piston upwardly so that the chamfered portion 12a aligns with the lowermost portion 1 of the bore 16b.
Hold the piston at the position where it hits point 6c and stops.
On the upper surface of the caul plate 24 there is a hard rubber block (similar to a hockey pack) 25 which contacts the elevator lid or counterweight which pushes the object, i.e. the piston, down into the cylinder (into the liquid). .

A filling port 26 is arranged at a certain height of the cylinder. The fill port is at a certain angle 30 to the horizontal 32 and can be fitted with a screw cap. Angle 30 is about 20 degrees in the preferred embodiment, and allows the lowest surface 26a at the outermost portion of fill port 26 to
Liquid can be injected into the cylinder until a level corresponding to the level of is reached. (If the angle is too large, air will be trapped inside the cylinder and you won't be able to put in as much liquid.) The upper level UL and the lower level LL determined by the lower surface 26b of the innermost part of the fill port are , are the maximum liquid level and the minimum liquid level, respectively,
Inspection can be done by simply looking into the filling port.

When the buffer is activated (pushed down under load), liquid is pushed up within chamber 19b.
This occurs through port 18a of inner cylinder 18, as previously discussed. This internal cylinder is
It does not extend upwardly into the sleeve, i.e. there is a small gap 19d between the sleeve 16a and the upper end of the cylinder 18, and the upper end of the cylinder 18 extends around the piston to provide a drainage channel around the piston. It should be noted that the edges are chamfered. This shape creates a nozzle. As the liquid is pushed up (see arrow 40),
The disturbance of the liquid as it rises creates a liquid/air mixture (illustrated by bubbles) in the upper region.
This mixture fills the gap 19 which acts as a nozzle.
b. In other words, the gap 19b
Air and liquid (oil) are separated by disturbance and pressure changes before and after. The liquid is in chamber 1 around the piston.
9c (acting as a funnel) and lubricates the piston as it descends. Air is forced up under pressure in the cylinder and forced through the gap between the piston and the sleeve, removing dust and dirt from the gap (which should be as clean as possible). In contrast, conventional shock absorbers have seals placed in the gap around the piston for cleaning and sealing purposes. However, the seals deteriorate (due to the dirt and grime they wipe off, as well as age), so they usually need to be replaced from time to time. However, this buffer has
There are no such seals and therefore no such routine maintenance is required.

Effects of the Invention From the above description, compared to conventional shock absorbers, the shock absorber using the present invention is very simple, reliable, inexpensive, and easy to maintain.

From the above description of a buffer employing the present invention, various modifications and changes will occur to those skilled in the art without departing from the true scope and spirit of the invention.

[Brief explanation of drawings]

FIG. 1 has been partially cut away along line 1--1 in FIG. 2 to reveal its internal components and fluid. A front view of the hydraulic shock absorber according to the present invention, FIG. 2 is a plan view taken in the direction 2--2 of FIG. 1, and FIG. 3 is a partially enlarged view of FIG. 1. DESCRIPTION OF SYMBOLS 10... Buffer, 12... Piston, 12a... Chamfered part, 12b... Ring-shaped cut, 16...
Container, 16a...Sleeve, 16b...Bore, 16c
...lowest end portion, 18...inner cylinder, 18a...port, 19a...first chamber, 19b...second chamber, 19c
...Gathering area, 19d...Small annular passage (gap), 2
0...liquid, 22...spring, 24...back plate, 25...hard rubber block, 26...filling port, 26a...lowest surface of the outermost part of filling port, 26b...
Low surface of the innermost part of the filling port, 28... Height at which the filling port is provided, 30... Angle, 32
...Horizontal line, 40...An arrow indicating the rise of the liquid.

Claims (1)

[Claims] 1 a container, an internal cylinder within the container, and a piston, the internal cylinder having two chambers communicating with the container, one chamber within the internal cylinder, and around the other internal cylinder by a port. the piston extends into the inner cylinder through a portion of the sleeve at the top of the container above the inner cylinder, and there is a cavity between the piston and the sleeve for draining air from within the container; a small annular passage is provided between the container and the upper edge of the inner cylinder for passage of the liquid/air mixture from said other chamber to said cavity and serving as a nozzle;
Thereby, as the liquid/air mixture is forced through its small annular passage, the volume of the liquid/air mixture expands, along the piston the liquid condenses and lubricates the piston, and air is released from said cavity. A hydraulic shock absorber characterized by: