CA1224426A - Hydraulic buffer for elevators - Google Patents
Hydraulic buffer for elevatorsInfo
- Publication number
- CA1224426A CA1224426A CA000457431A CA457431A CA1224426A CA 1224426 A CA1224426 A CA 1224426A CA 000457431 A CA000457431 A CA 000457431A CA 457431 A CA457431 A CA 457431A CA 1224426 A CA1224426 A CA 1224426A
- Authority
- CA
- Canada
- Prior art keywords
- piston
- container
- fluid
- cylinder
- buffer
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 239000000872 buffer Substances 0.000 title claims abstract description 38
- 239000012530 fluid Substances 0.000 claims abstract description 45
- 239000000203 mixture Substances 0.000 claims abstract description 11
- 239000007788 liquid Substances 0.000 claims 1
- 239000000356 contaminant Substances 0.000 abstract description 4
- 230000001050 lubricating effect Effects 0.000 abstract description 3
- 239000000428 dust Substances 0.000 description 4
- 239000000945 filler Substances 0.000 description 4
- 230000007423 decrease Effects 0.000 description 3
- 238000012423 maintenance Methods 0.000 description 3
- 238000013019 agitation Methods 0.000 description 2
- 238000004140 cleaning Methods 0.000 description 2
- XUKUURHRXDUEBC-KAYWLYCHSA-N Atorvastatin Chemical compound C=1C=CC=CC=1C1=C(C=2C=CC(F)=CC=2)N(CC[C@@H](O)C[C@@H](O)CC(O)=O)C(C(C)C)=C1C(=O)NC1=CC=CC=C1 XUKUURHRXDUEBC-KAYWLYCHSA-N 0.000 description 1
- 229920001875 Ebonite Polymers 0.000 description 1
- 241000282320 Panthera leo Species 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000007689 inspection Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000000750 progressive effect Effects 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- 238000011144 upstream manufacturing Methods 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B66—HOISTING; LIFTING; HAULING
- B66B—ELEVATORS; ESCALATORS OR MOVING WALKWAYS
- B66B5/00—Applications of checking, fault-correcting, or safety devices in elevators
- B66B5/28—Buffer-stops for cars, cages, or skips
- B66B5/282—Structure thereof
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
- F16F9/00—Springs, vibration-dampers, shock-absorbers, or similarly-constructed movement-dampers using a fluid or the equivalent as damping medium
- F16F9/06—Springs, vibration-dampers, shock-absorbers, or similarly-constructed movement-dampers using a fluid or the equivalent as damping medium using both gas and liquid
- F16F9/062—Bi-tubular units
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
- F16F9/00—Springs, vibration-dampers, shock-absorbers, or similarly-constructed movement-dampers using a fluid or the equivalent as damping medium
- F16F9/32—Details
- F16F9/48—Arrangements for providing different damping effects at different parts of the stroke
Abstract
Abstract Hydraulic Buffer for Elevators A hydraulic elevator buffer contains a piston (plunger) which is pushed down into a volume of hydraulic fluid. The buffer has no seals separating its interior from the atmosphere. As the piston is pushed down, the displaced fluid is forced through ports in the cylinder which gives rise to a restrict-ing force. The displaced fluid escapes into a volume in which an air/fluid mixture is produced. A nozzle area surrounds the piston at the top of the container, and the mixture is forced through the nozzle, separating the fluid and air. The fluid condenses down, lubricat-ing the piston. The air is forced out through the space between the fluid container and the piston, removing any contaminants around the piston. The buffer contains a fluid-fill port which is at a horizontal angle at which a minimum and maximum fluid level in the buffer can be determined by looking in the port. The maximum is the level at which the fluid flows out of the port, and the minimum is the lowest level at which the fluid can be seen through the port.
Description
~L~2~
Description Hydraulic Buffer for Elevators Technical Field This invention concerns elevators, specifically, elevator buffers~
Background Art Hydraulic buffers are used in elevators to decelerate the elevator car or the counterweight under certain conditions. The typical hydraulic buffer has a heavy fluid container and a piston that extends into this container to force fluid through the ports. This flow produces progressive deceleration, and the deceleration pattern is determined by the location of the ports along the direction in which the piston moves.
All current hydraulic elevator buffers of this type use piston seals to clos~ off the space around the piston rod and the container to prevent entry of contaminating material, such as dust (which can abrade the piston and seal surfaces during buffer operations, e.g., during performance service checks) and to prevent the air/fluid mixture that results from a buffer operation Erom escaping.
Moreover, the external seals deteriorate over time;
sometimes becoming brittle. Buffer service life is highly dependent on the eEfectiveness of those piston seals in blocking contaminants and preventing fluid from escaping.
Mainly because of the seals, currently available buffers are comparatively expensive to construct and expensive and difficult to maintain, and require routine maintenance to check the sealsO
~ ,
Description Hydraulic Buffer for Elevators Technical Field This invention concerns elevators, specifically, elevator buffers~
Background Art Hydraulic buffers are used in elevators to decelerate the elevator car or the counterweight under certain conditions. The typical hydraulic buffer has a heavy fluid container and a piston that extends into this container to force fluid through the ports. This flow produces progressive deceleration, and the deceleration pattern is determined by the location of the ports along the direction in which the piston moves.
All current hydraulic elevator buffers of this type use piston seals to clos~ off the space around the piston rod and the container to prevent entry of contaminating material, such as dust (which can abrade the piston and seal surfaces during buffer operations, e.g., during performance service checks) and to prevent the air/fluid mixture that results from a buffer operation Erom escaping.
Moreover, the external seals deteriorate over time;
sometimes becoming brittle. Buffer service life is highly dependent on the eEfectiveness of those piston seals in blocking contaminants and preventing fluid from escaping.
Mainly because of the seals, currently available buffers are comparatively expensive to construct and expensive and difficult to maintain, and require routine maintenance to check the sealsO
~ ,
-2 Disclosure of Invention A principal object of the invention is to provide a very inexpensive buffer that requires no seal inspec-tion or service.
According to the present invention, a hydraulic fluid buffer has a piston (plunger) which extends through a sleeve in the top of a partially filled fluid (oil) container into an internal cylinder, also partially filled. When the piston is thrust down, hydraulic fluid is forced from the cylinder, which produces a fluid/air mixture within the container as the fluid level rises.
This mixture is forced (by the action of the piston) through a fluid separator (e.g., a small passage) that surrounds the piston at the upper portion of the con-tain~r, and the fluid and air in the mixture separate.The fluid drops out and is directed (e.g., funneled) to the piston, lubricating the piston as it travels down.
The air is forced out of the container through the sleeve, removing contaminants, such as dust, from the space between the piston and the sleeve. As a result of this configuration, no seals are needed for the purpose of cleaning the piston or preventing fluid escaping from the container.
The present invention thus provides a buffer with a number of features. The buffer has no seals of any kind; all parts can be metallic. It requires no maintenance. Buffer test operation removes contaminants from the space around the piston. Fluid l~vel can be checked easily, without a dipstick, simply by opening the port and looking in. If the fluid is not visible, it is below the minimum; if i~ is visible, it is at least at the minimum and no greater than the maximum (i.e., in a safe range).
~3~ ~%4~
A feature of the invention is the buffer may be easily and economically constructed as a single assembly, with all parts permanently attached (i.e., welded together) because no fasteners of any kind need to be used.
The invention thus offers an exceptionally simple, inexpensive and virtually maintenance-free buffer.
Brief Description of Drawings Fig. 1, an elevational view of an hydraulic buffer according to the present invention, shows the buffer partially cut away along section line 1-1 in Fig. 2, exposing its internal components and the fluid;
Fig. 2 is a plan view in the direction 2-2 in Fig. l; and Fig. 3 is a magnified view of a portion of Fig. 1.
Best Mode for Carrying Out the Invention Referring to Fig. 1, a buffer 10 according to the present invention includes a piston 12 (i.e., a rod) which extends through a sleeve lOa into a container 16.
Within this container 16b is an internal cylinder 18, so to speak, which receives the piston and guides it as it moves in and out of the buffer 10. The piston has a slightly elevated chamfered portion 12a which acts as a stop when it engages the portion 16a on the sleeve. The sleeve extends comparatively tightly around the piston to provide a good metal-to-metal seal. The piston 12 also slides tightly within the internal cylinder 18. The cylinder 18 defines a first chamber 19a, a second chamber l9b outside it, and at the top a collec-tion area 19c. Both chambers are partially filled with fluid (oil). There ls a small annular passagP 19d around the piston at the uppermost part of the cylinder 18 ~4~
which separates chambers l9b and l9c, and it acts as a no~zle to separate oil and air (this is e~plained below~.
The ratio between the height of the passage and its width (along the circumference of the cylinder 18) is .013. The ratio of the flow area upstream (below) the passage to the area at the passage is 120, and the ratio at the passage to the area downstream (near the piston) is 13. The passage thus operates as a nozzle.
In addition, the space between the piston and the slee~e constitutes a second noæzle downstream, through which air may escape from the container under pressure therein, and that air must flow from the first nozzle and, as explained below, cleans the space in the second nozzle.
The piston 12 contains ring=like cuts l~b along its lower end, and they pro~ide an hydraulic dynamic seal without the use of rings, because hydraulic fluid in these seals is evenly distributed, under even pressure, around the piston, which helps align the piston and lubricate it as it moves in the internal cylinder 1~.
(As an alternative, a single metallic piston ring may be used in the groove urthest from the piston face to limit the flow past the piston.) Following conventional tech nology, the cylinder contains por~s 18a along that part of its vertical length that is within the area immersed in fluid 20. As the piston strokes down, fluid is displaced through these ports from chamber 19a to chamber l9b. The number of remaining ports decreases (this is not shown) during the downstroke, and thus the flow area decreases, which increases the resistance to fluid flow as the piston moves down the cylinder. At the same time, the piston speed decreases as the ele~ator is decelerated _5~ 2~
and the rate of flow of fluid through the port area is correspondingly reduced. Thus, the buffer stopping force remains substantially constant with piston dis-placement, thus imparting a substantially uniform deceleration to the elevator. A spring 22 surrounds the piston 12 and is located at the uppermost portion of the piston between the cylinder 16 and the striker plate 24. The spring biases the piston up, holding it in a position at which the chamfer portion 12a rests against the lowes~most portion 16c bore 16b. On top of the plate is a hard rubber block (resembling a hockey puck) 26, which is contacted by the object, i.e., the elevator cap or counterweight, to force the piston down into the cylinder (into the fluid).
A filler hole 26 is located at a special vertical height 28 on the cylinder. It may have a screw-in cap and is oriented at a special angle 30 to the horizontal 32. The angle 30, which in the preferred embodiment is about 20, is such that fluid can be poured into the cylinder until it reaches a level which corresponds to the level of the lowest surface 26a on the outermost portion of the filler hole 26. (If the angle is too high, air will be trapped inside the cylinder, preventing more fluid from entering.) The distance 34 between the upper level U~ and the lower level LL, defined by the lower surface 26b of the innermost portion of the filler hole, is the minimum and maximum fluid levels; simply by looking in the filler hole that can be checked.
During operation of the buffer (as it i5 pushed down under load) fluid is pushed up in chamber l9b, and this occurs, as mentioned, through the ports 18a in the internal cylinder 18. It should not go unnoticed that this internal cylinder does not extend all the way -6- ~442~
up to the cap; there is that small space l9d between the lid 16a and the upper portion of the cylinder 18, which is chamfered (see Fig. 3) around the piston to provide a fluid funnel around the piston. This configuration creates a nozæle. As the fluid is pushed up (see arrow 40), a mixture of fluid and air (the bubbles that are shown) is produced, in the upper area by the fluid agitation as the fluid rises. This mixture is forced through the space l9b, and it acts as a noz21e; that is, agitation and pressure change across the space cause the air and fluid (oil) to separate, and the fluid drops down (condenses) in chamber l9c (it acts as a funnel) around the piston, lubricating the piston as it mo~es down. The air is forced up under the pressure in the cylinder and out through the space between the piston and the sleeve, removing dirt and dust from that space (it should be as clean as possible). In contrast, other buffers have seals that are located in the space around the piston for these cleaning and sealing purposes.
But, the seals deteriorate (as a result of the dirt and dust which they wipe of and age), and, as a result, normally have to be replaced from time-to-time~ But, in this buffer such seals are not present, and hence, such routine maintenance is unnecessary.
The foregoing demonstrates that by comparison to current buffers, a buffer embodyin~ the present invention is ver~ simple and reliable, inexpensive and easy to maintain.
The foregoing descrip-~ion of a buffer embodying the present invention ~ill suggest, to one skilled in the art, various modifications and alterations, without departing from the true scope and spirit of the invention.
., ~
According to the present invention, a hydraulic fluid buffer has a piston (plunger) which extends through a sleeve in the top of a partially filled fluid (oil) container into an internal cylinder, also partially filled. When the piston is thrust down, hydraulic fluid is forced from the cylinder, which produces a fluid/air mixture within the container as the fluid level rises.
This mixture is forced (by the action of the piston) through a fluid separator (e.g., a small passage) that surrounds the piston at the upper portion of the con-tain~r, and the fluid and air in the mixture separate.The fluid drops out and is directed (e.g., funneled) to the piston, lubricating the piston as it travels down.
The air is forced out of the container through the sleeve, removing contaminants, such as dust, from the space between the piston and the sleeve. As a result of this configuration, no seals are needed for the purpose of cleaning the piston or preventing fluid escaping from the container.
The present invention thus provides a buffer with a number of features. The buffer has no seals of any kind; all parts can be metallic. It requires no maintenance. Buffer test operation removes contaminants from the space around the piston. Fluid l~vel can be checked easily, without a dipstick, simply by opening the port and looking in. If the fluid is not visible, it is below the minimum; if i~ is visible, it is at least at the minimum and no greater than the maximum (i.e., in a safe range).
~3~ ~%4~
A feature of the invention is the buffer may be easily and economically constructed as a single assembly, with all parts permanently attached (i.e., welded together) because no fasteners of any kind need to be used.
The invention thus offers an exceptionally simple, inexpensive and virtually maintenance-free buffer.
Brief Description of Drawings Fig. 1, an elevational view of an hydraulic buffer according to the present invention, shows the buffer partially cut away along section line 1-1 in Fig. 2, exposing its internal components and the fluid;
Fig. 2 is a plan view in the direction 2-2 in Fig. l; and Fig. 3 is a magnified view of a portion of Fig. 1.
Best Mode for Carrying Out the Invention Referring to Fig. 1, a buffer 10 according to the present invention includes a piston 12 (i.e., a rod) which extends through a sleeve lOa into a container 16.
Within this container 16b is an internal cylinder 18, so to speak, which receives the piston and guides it as it moves in and out of the buffer 10. The piston has a slightly elevated chamfered portion 12a which acts as a stop when it engages the portion 16a on the sleeve. The sleeve extends comparatively tightly around the piston to provide a good metal-to-metal seal. The piston 12 also slides tightly within the internal cylinder 18. The cylinder 18 defines a first chamber 19a, a second chamber l9b outside it, and at the top a collec-tion area 19c. Both chambers are partially filled with fluid (oil). There ls a small annular passagP 19d around the piston at the uppermost part of the cylinder 18 ~4~
which separates chambers l9b and l9c, and it acts as a no~zle to separate oil and air (this is e~plained below~.
The ratio between the height of the passage and its width (along the circumference of the cylinder 18) is .013. The ratio of the flow area upstream (below) the passage to the area at the passage is 120, and the ratio at the passage to the area downstream (near the piston) is 13. The passage thus operates as a nozzle.
In addition, the space between the piston and the slee~e constitutes a second noæzle downstream, through which air may escape from the container under pressure therein, and that air must flow from the first nozzle and, as explained below, cleans the space in the second nozzle.
The piston 12 contains ring=like cuts l~b along its lower end, and they pro~ide an hydraulic dynamic seal without the use of rings, because hydraulic fluid in these seals is evenly distributed, under even pressure, around the piston, which helps align the piston and lubricate it as it moves in the internal cylinder 1~.
(As an alternative, a single metallic piston ring may be used in the groove urthest from the piston face to limit the flow past the piston.) Following conventional tech nology, the cylinder contains por~s 18a along that part of its vertical length that is within the area immersed in fluid 20. As the piston strokes down, fluid is displaced through these ports from chamber 19a to chamber l9b. The number of remaining ports decreases (this is not shown) during the downstroke, and thus the flow area decreases, which increases the resistance to fluid flow as the piston moves down the cylinder. At the same time, the piston speed decreases as the ele~ator is decelerated _5~ 2~
and the rate of flow of fluid through the port area is correspondingly reduced. Thus, the buffer stopping force remains substantially constant with piston dis-placement, thus imparting a substantially uniform deceleration to the elevator. A spring 22 surrounds the piston 12 and is located at the uppermost portion of the piston between the cylinder 16 and the striker plate 24. The spring biases the piston up, holding it in a position at which the chamfer portion 12a rests against the lowes~most portion 16c bore 16b. On top of the plate is a hard rubber block (resembling a hockey puck) 26, which is contacted by the object, i.e., the elevator cap or counterweight, to force the piston down into the cylinder (into the fluid).
A filler hole 26 is located at a special vertical height 28 on the cylinder. It may have a screw-in cap and is oriented at a special angle 30 to the horizontal 32. The angle 30, which in the preferred embodiment is about 20, is such that fluid can be poured into the cylinder until it reaches a level which corresponds to the level of the lowest surface 26a on the outermost portion of the filler hole 26. (If the angle is too high, air will be trapped inside the cylinder, preventing more fluid from entering.) The distance 34 between the upper level U~ and the lower level LL, defined by the lower surface 26b of the innermost portion of the filler hole, is the minimum and maximum fluid levels; simply by looking in the filler hole that can be checked.
During operation of the buffer (as it i5 pushed down under load) fluid is pushed up in chamber l9b, and this occurs, as mentioned, through the ports 18a in the internal cylinder 18. It should not go unnoticed that this internal cylinder does not extend all the way -6- ~442~
up to the cap; there is that small space l9d between the lid 16a and the upper portion of the cylinder 18, which is chamfered (see Fig. 3) around the piston to provide a fluid funnel around the piston. This configuration creates a nozæle. As the fluid is pushed up (see arrow 40), a mixture of fluid and air (the bubbles that are shown) is produced, in the upper area by the fluid agitation as the fluid rises. This mixture is forced through the space l9b, and it acts as a noz21e; that is, agitation and pressure change across the space cause the air and fluid (oil) to separate, and the fluid drops down (condenses) in chamber l9c (it acts as a funnel) around the piston, lubricating the piston as it mo~es down. The air is forced up under the pressure in the cylinder and out through the space between the piston and the sleeve, removing dirt and dust from that space (it should be as clean as possible). In contrast, other buffers have seals that are located in the space around the piston for these cleaning and sealing purposes.
But, the seals deteriorate (as a result of the dirt and dust which they wipe of and age), and, as a result, normally have to be replaced from time-to-time~ But, in this buffer such seals are not present, and hence, such routine maintenance is unnecessary.
The foregoing demonstrates that by comparison to current buffers, a buffer embodyin~ the present invention is ver~ simple and reliable, inexpensive and easy to maintain.
The foregoing descrip-~ion of a buffer embodying the present invention ~ill suggest, to one skilled in the art, various modifications and alterations, without departing from the true scope and spirit of the invention.
., ~
Claims (3)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS.
1. A hydraulic buffer, for location at the bottom of an elevator shaft to decelerate an elevator car, characterized by:
a container for buffer oil;
a piston cylinder within said container, said piston cylinder defining two fluid chambers within the container, one within the piston cylinder, the second around the piston cylinder, said piston cylinder containing ports connecting the two chambers;
a piston extending through a congruent sleeve in the top of the container into said piston cylinder, said sleeve being above the top of said piston cylinder, there being a space between the piston and the sleeve allowing air to escape from the interior of the container to the surrounding environment outside said container, said space extending around the piston for the entire length of the sleeve;
the top of the piston cylinder and the top of the container defining a nozzle between the uppermost portion of the second chamber to an area on top of said piston cylinder, that is within the container and directly exposed to the piston and the sleeve, said nozzle providing a volumetric expansion to an oil/air mixture forced therethrough to said area from the second chamber whereby the oil condenses from said mixture as it passes through the nozzle and air in the mixture escapes through the space between the sleeve and the piston to aid in maintaining said space free from blockage; and a spring that extends the piston out of the container.
a container for buffer oil;
a piston cylinder within said container, said piston cylinder defining two fluid chambers within the container, one within the piston cylinder, the second around the piston cylinder, said piston cylinder containing ports connecting the two chambers;
a piston extending through a congruent sleeve in the top of the container into said piston cylinder, said sleeve being above the top of said piston cylinder, there being a space between the piston and the sleeve allowing air to escape from the interior of the container to the surrounding environment outside said container, said space extending around the piston for the entire length of the sleeve;
the top of the piston cylinder and the top of the container defining a nozzle between the uppermost portion of the second chamber to an area on top of said piston cylinder, that is within the container and directly exposed to the piston and the sleeve, said nozzle providing a volumetric expansion to an oil/air mixture forced therethrough to said area from the second chamber whereby the oil condenses from said mixture as it passes through the nozzle and air in the mixture escapes through the space between the sleeve and the piston to aid in maintaining said space free from blockage; and a spring that extends the piston out of the container.
2. A hydraulic buffer, for location at the bottom of an elevator shaft to decelerate an elevator car, characterized by:
a container for buffer oil;
a piston which extends through the top of the container, there being an air-flow space completely around the piston between the piston and the container where the piston extends therefrom allowing air to escape from the interior of the container to the surrounding environment outside said container such that said space is maintained free from blockage;
a piston cylinder within the container to create a first chamber within the cylinder and a second chamber around the cylinder and containing ports connecting the two chambers, said piston extending into said cylinder, the top of said piston cylinder being in close proximity to, but spaced from, the top of the liquid container creating a narrow annular passage between the second chamber and an annular space on top of the piston cylinder around the piston at the point at which the piston passes through the container and within the container; and a spring that extends the piston out of the container.
a container for buffer oil;
a piston which extends through the top of the container, there being an air-flow space completely around the piston between the piston and the container where the piston extends therefrom allowing air to escape from the interior of the container to the surrounding environment outside said container such that said space is maintained free from blockage;
a piston cylinder within the container to create a first chamber within the cylinder and a second chamber around the cylinder and containing ports connecting the two chambers, said piston extending into said cylinder, the top of said piston cylinder being in close proximity to, but spaced from, the top of the liquid container creating a narrow annular passage between the second chamber and an annular space on top of the piston cylinder around the piston at the point at which the piston passes through the container and within the container; and a spring that extends the piston out of the container.
3. A hydraulic buffer according to claim 1 or 2, further characterized in that:
the top of the piston cylinder is chamfered to create a small annular oil collection reservoir around the piston.
the top of the piston cylinder is chamfered to create a small annular oil collection reservoir around the piston.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US51252083A | 1983-07-11 | 1983-07-11 | |
| US512,520 | 1983-07-11 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1224426A true CA1224426A (en) | 1987-07-21 |
Family
ID=24039448
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000457431A Expired CA1224426A (en) | 1983-07-11 | 1984-06-26 | Hydraulic buffer for elevators |
Country Status (14)
| Country | Link |
|---|---|
| JP (1) | JPS6037434A (en) |
| AT (1) | AT396582B (en) |
| AU (1) | AU575058B2 (en) |
| CA (1) | CA1224426A (en) |
| CH (1) | CH665892A5 (en) |
| DE (1) | DE3425385A1 (en) |
| ES (1) | ES289725Y (en) |
| FI (1) | FI79072C (en) |
| FR (1) | FR2549183B1 (en) |
| GB (1) | GB2143613B (en) |
| HK (1) | HK61388A (en) |
| IN (1) | IN161296B (en) |
| IT (1) | IT1179393B (en) |
| SG (1) | SG99487G (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112707263A (en) * | 2021-01-27 | 2021-04-27 | 陕西省特种设备检验检测研究院 | Bottom impact-proof system of elevator |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2608306B1 (en) * | 1986-12-10 | 1989-03-31 | Framatome Sa | ABSORBENT BAR FALL DAMPING DEVICE FOR NUCLEAR FUEL ASSEMBLY |
| US4926981A (en) * | 1989-06-19 | 1990-05-22 | Otis Elevator Company | Escalator step buffer |
| GB201006713D0 (en) * | 2010-04-22 | 2010-06-09 | T A Savery And Co Ltd | A buffer |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2040063A (en) * | 1932-10-17 | 1936-05-05 | Gen Motors Corp | Direct action shock absorber |
| JPS5141580Y2 (en) * | 1971-07-16 | 1976-10-08 | ||
| DE2440094C3 (en) * | 1974-08-21 | 1980-08-28 | Thyssen Aufzuege Gmbh, 7000 Stuttgart | Elevator buffer |
| DE3044460A1 (en) * | 1980-11-26 | 1982-06-24 | August Bilstein GmbH & Co KG, 5828 Ennepetal | HYDROPNEUMATIC TWO TUBE VIBRATION DAMPER, ESPECIALLY AS A FRONT AXLE FOR MOTOR VEHICLES |
-
1984
- 1984-06-20 IN IN500/DEL/84A patent/IN161296B/en unknown
- 1984-06-26 CA CA000457431A patent/CA1224426A/en not_active Expired
- 1984-06-29 AU AU30033/84A patent/AU575058B2/en not_active Ceased
- 1984-07-02 FI FI842662A patent/FI79072C/en not_active IP Right Cessation
- 1984-07-06 AT AT0218584A patent/AT396582B/en active
- 1984-07-09 IT IT48533/84A patent/IT1179393B/en active
- 1984-07-10 DE DE19843425385 patent/DE3425385A1/en active Granted
- 1984-07-10 CH CH3347/84A patent/CH665892A5/en not_active IP Right Cessation
- 1984-07-10 ES ES1984289725U patent/ES289725Y/en not_active Expired
- 1984-07-11 FR FR8411011A patent/FR2549183B1/en not_active Expired
- 1984-07-11 JP JP59144089A patent/JPS6037434A/en active Granted
- 1984-07-11 GB GB08417676A patent/GB2143613B/en not_active Expired
-
1987
- 1987-11-12 SG SG994/87A patent/SG99487G/en unknown
-
1988
- 1988-08-11 HK HK613/88A patent/HK61388A/en not_active IP Right Cessation
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112707263A (en) * | 2021-01-27 | 2021-04-27 | 陕西省特种设备检验检测研究院 | Bottom impact-proof system of elevator |
| CN112707263B (en) * | 2021-01-27 | 2022-04-05 | 陕西省特种设备检验检测研究院 | Bottom impact-proof system of elevator |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0424582B2 (en) | 1992-04-27 |
| FI79072C (en) | 1989-11-10 |
| GB2143613A (en) | 1985-02-13 |
| ATA218584A (en) | 1993-02-15 |
| FI79072B (en) | 1989-07-31 |
| AU575058B2 (en) | 1988-07-21 |
| CH665892A5 (en) | 1988-06-15 |
| DE3425385A1 (en) | 1985-01-24 |
| FR2549183B1 (en) | 1988-12-09 |
| ES289725Y (en) | 1986-10-16 |
| AT396582B (en) | 1993-10-25 |
| ES289725U (en) | 1986-03-01 |
| GB8417676D0 (en) | 1984-08-15 |
| JPS6037434A (en) | 1985-02-26 |
| SG99487G (en) | 1988-07-15 |
| AU3003384A (en) | 1985-01-17 |
| IT8448533A0 (en) | 1984-07-09 |
| HK61388A (en) | 1988-08-19 |
| IN161296B (en) | 1987-11-07 |
| DE3425385C2 (en) | 1992-07-02 |
| FR2549183A1 (en) | 1985-01-18 |
| FI842662A (en) | 1985-01-12 |
| FI842662A0 (en) | 1984-07-02 |
| IT1179393B (en) | 1987-09-16 |
| GB2143613B (en) | 1986-10-01 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |