US3857555A

US3857555A - Oil buffer

Info

Publication number: US3857555A
Application number: US00400738A
Authority: US
Inventors: A Mori; N Mitsui
Original assignee: Hitachi Ltd
Current assignee: Hitachi Ltd
Priority date: 1972-09-29
Filing date: 1973-09-26
Publication date: 1974-12-31
Anticipated expiration: 1991-12-31
Also published as: JPS4956084A; GB1427055A; JPS5216555B2; CA986430A

Abstract

An oil buffer in which a tapered control rod is provided in a cylinder and an oil injection hole through which said control rod passes is provided at the bottom of a plunger slidable in said cylinder so that oil in the cylinder will be injected into said plunger to produce a buffer action, and further characterized in that an oil check is provided at the top in the inside of said plunger, said oil check being positioned above said oil injection hole so as to force back downwardly the oil injected from said oil injection hole and adapted to control the amount of oil gushing out of said plunger through an air hole provided at the top of said oil check.

Description

ilnited States Patent 1191 1111 3,857,555 Mori et al. I Dec. 31, 1974 [54] OIL BUFFER 3,033,384 5/1962 Zanow et a1. 188/289 [75] Inventors: Akihiro Mori; Norihiko Mitsui, both f Katsuta, Japan Primary Examiner-James B. Marbert Attorney, Agent, or FirmCraig & Antonelli [73] Asslgnee: Hitachi, Ltd., Tokyo, Japan [21] Appl. No.: 400,738 An oil buffer in which a tapered control rod is provided in a cylinder and an oil injection hole through [30] Foreign Application Priority D t which said control rod passes is provided at the bot- Sept. 29, 1972 Japan .1 47-96988 [52] US. Cl.., 267/34, 267/116, 188/269,

188/289 1 [51] Int. C1. ....B60 11/56 [58] Field of Search 267/34, 116; 188/289, 211, 188/269 56] References Cited UNITED STATES PATENTS 1,125,942 1/1915 Blanchard ..-188/269 tom of a plunger slidable in said cylinder so that oil in the cylinder will be injected into said plunger to produce a buffer action, and further characterized in that an oil check is provided at the top in the inside of said plunger, said oil check being positioned above said oil injection hole so as to force back downwardly the oil injected from said oil injection hole and adapted to control the amount of oil gushing out of said plunger through an air hole provided at the top of said oil check.

12 Claims, 2 Drawing Figures OIL BUFFER This invention relates to an oil buffer, and more particularly to an oil buffer most suited for use in a lift.

Generally, in this type of oil buffers, a return spring is loaded around the control rod disposed in the cylinder, and the plunger is provided with an air hole for ejecting air in the plunger as the latter descends when a shock is developed. Therefore, when air flows out from the air hole during the buffering operation, the oil which has flown into the plunger through an oil hole provided at the bottom of the plunger would be caused to flow out in an atomized state, so that if the device is adapted in an elevator pit, the inside of the pit would be soiled with oil. Also, if the amount of effluent oil is large, it was necessary to supply additional oil at the time of re-starting.

Further, in the arrangement where a return coil spring is provided around the control rod in the cylinder, if the plunger stroke is made longer, said return coil spring must be also elongated correspondingly. This results in elongation of the portion which remains flexed after operation, necessitating corresponding elongation of the cylinder length. Thus, if the device is adapted in an elevator pit, it becomes necessary to expand the pit depth.

An object of the present invention is to provide a device which permits lessening of the amount of oil injected, so as to minimize or unnecessitate additional supply of oil at the time of re-starting.

Another object of the present invention is to provide a device in which oil gushed out from the air hole wont be scattered to the surrounding.

Still another object of the present invention is to provide a mechanism which permits shortening of the cylinder length.

More specifically, the present invention is aimed at providing an improved oil buffer device in which a tapered control rod is provided in the cylinder and an oil injection hole designed to allow passage of said control rod is provided at the bottom of a plunger arranged slidable in the cylinder, so that oil in said cylinder will be injected into said plunger to perform a buffer action, and further characterized in that an oil check is pro vided at the inside top of said plunger, said oil check being positioned above said injection hole so that the oil injected from said injection hole will be forced back downwardly, and an air hole for ejecting air in the plunger is provided at an upper part of said oil check.

These and other arrangements of the present invention for accomplishing the above-said objects will become apparent from the following detailed description of an embodiment of the present invention.

FIG. 1 is a general vertical sectional view, as taken from the front side, of an oil'buffer according to an embodiment of the present invention, and

FIG. 2 is a detail drawing of the spring-loaded portion.

Centrally in a cylinder 1 is provided a tapered control rod 2. A plunger 3 is provided slidably into said cylinder 1 through an injection hole 4 such that when said plunger 3 descends, oil reservoired in the cylinder 1 will be injected into said plunger through said injection hole 4. Since the control rod 2 is tapered upwardly, a large amount of oil is injected in the early stage of de scent of the plunger, but as its descent advances, the

amount of oil injected is gradually decreased, thereby to produce a buffer action. At the top and inside of said plunger 3 is provided a cylindrical oil check 6 which has formed in its side an air hole 5 through which air in the plunger 3 is vented out to urge smooth descent of said plunger 3. This oil check 6 is so arranged that when oil is injected from the. injection hole 4, such injected oil will be forced back downwardly upon hitting its underside 6A so as to minimize oil effluence from the air hole 5. On the top of said plunger 3 is provided a box-shaped hollow support 7 which is communicated with the inside of the oil check 6 through an opening 8. On said support 7 is provided, through a base 10, a rubber seat 9 adapted to preclude or minimize damage when an object to be buffered strikes down thereagainst. At both sides of said support 7 are provided cylindrical bodies ll, 11 the inside of which is communicated with the inside of the support 7 through

holes

12, 12, respectively. There are also provided

cylindrical bodies

13, 13 supported by the supporting arms l4, 14 which are secured to the outer periphery of the cylinder 1. Said cylindrical bodies l3, 13' are designed to receive therein said cylindrical bodies 11, 11', respectively. Around these cylindrical bodies 11, ll, l3, 13 are provided plunger-returning

coil springs

15, 15 composed from several pieces of short springs. In the conventional devices, such coil spring was mounted around the control rod in the inside of the cylinder, so that if the coil spring is made longer,its flexed portion is also elongated, necessitating equivalent elongation of the cylinder length.

Inthe shown embodiment of thev present invention, the coil springs are disposed between the bottom end of the support 7 on the outside of the cylinder and the supporting arms 14, 14', so that their length can be sufficiently absorbed to unnecessitate under elongation of the cylinder. Also, in case the coil spring 15 is formed from a single piece of spring, its manufacture is attended by great difficulty. But, according to the present invention, since such coil spring is disposed outside of the cylinder, it can be composed from combination of several pieces of

short coil springs

15A, 15B, 15C, thus allowing obtainment of high-efficiency coil springs with high productivity. Said coil springs ISA, 15B, 15C are connected through spring seats 16 as shown in FIG. 2. In order to catch and collect oil flowing out from the plunger 3, there are provided oil receivers l8 on the base 17 to which the cylinder 1 is secured. When an object to be buffered (for example an elevator cage) strikes against the rubber seat 9, the plunger 3 descends, causing oil in the cylinder 1 to gush out from the oil hole 4. Although the thus ejected oil is mostly forced back downwardly by the underside 6A of the oil check 6, a portion of such oil flows into the oil check through the air hole 5 and hence further into the supporter 7 through hole 8 whence said oil further flows into the cylindrical bodies 11, 11 through holes l2, 12

and then into the cylindrical bodies 13, 13' and finally falls down into said oil receivers 18. Therefore, no oil is scattered away to the surrounding.

What is claimed is:

1. An oil buffer in which a tapered control rod is provided in a cylinder fixedly erected on a base and an oil injection hole arranged to allow passage of said control rod is provided at the bottom of a plunger arranged slidable in said cylinder so that oil in said cylinder will be injected into said plunger through the space between said control rod and injection hole so as to produce a buffer action, and further characterized in that an oil check is provided at the inside top of said plunger, said oil check having the underside positioned above said injection hole'so as to force back downwardly the oil which gushes out from said injection hole, and that air holes for ejecting air in the plunger are provided in the upper parts of said oil check.

2. An oil buffer according to claim 1, wherein said oil check is composed from a hollow cylindrical body having an oil-checking bottom, said cylindrical body also having formed above its bottom an air ejecting hole and a hole for communicating the inside of said oil check with the outside thereof.

3. An oil buffer according to claim 1, wherein coil springs for returning the plunger to its original position after each operation are provided outside of and in juxtaposition relative to the cylinder.

4. An oil buffer according to claim 3, wherein each said return coil spring is constituted from several pieces of short coil springs.

5. An oil buffer according to claim 3, wherein said return coil springs are provided around the cylindrical bodies which are arranged at the underside of said supporter.

6. An oil buffer in which a tapered control rod is provided in a cylinder fixedly erected on a base and an oil injection hole arranged to allow passage of said control rod is provided at the bottom of a plunger arranged slidable in said cylinder so that oil in said cylinder will be injected into said plunger through the space between said control rod and injection hole so as to produce a buffer action, characterized in that an oil check is provided at the inside top of said plunger, said oil check having the underside positioned above said oil injection hole so as to force back downwardly the oil which gushes out from said injection hole, and in that air holes for ejecting air in the plunger are provided in the upper parts of said oil check, a box-shaped supporter is provided at the top of said plunger, the inside of said supporter being communicated with the inside of said plunger through a hole and also communicated with oil receivers through cylindrical bodies.

7. An oil buffer in which a tapered control rod is provided in a cylinder fixedly erected on a base and an oil injection hole arranged to allow passage of said control rod is provided at the bottom of a plunger arranged slidably in said cylinder so that the oil in said cylinder will be injected into said plunger through the space between said control rod and injection hole so as to produce a buffer action, characterized in that said plunger is provided at its upper portion with a box-shaped supporter, the inside of said box-shaped supporter is communicated with the inside of said plunger through a hole, and spring guide members are provided and mounted on said box-shaped supporter at positions located separately from said plunger, and in that coil springs are provided for returning the plunger after each operation, said coil springs being disposed around each of said coil spring guide members.

8. An oil buffer according to claim 7, wherein each of said return coil springs is composed of several pieces of short coil springs.

9. An oil buffer according to claim 7, wherein said coil spring guide members are composed of hollow cylindrical bodies which are provided for oil passages, and wherein oil receiving means are provided on said base, said box-shaped supporter communicating with said oil receivers through said hollow cylindrical bodms.

10. An oil buffer according to claim 7, wherein an oil check is provided atthe inside top of said plunger, said oil check having the underside thereof positioned above said injection hole so as to force back downwardly the oil which gushes out from said injection hole, and said oil check is provided with air holes for venting air in the plunger, said air holes being communicated with said hole communicating the inside of said plunger with the inside of said box-shaped supporter.

11. An oil buffer according to claim 7, wherein said oil check is composed of a hollow cylinder having an oil-checking bottom portion, said cylindrical body having formed above said bottom portion said air holes and said hole communicating the inside of said plunger with said box-shaped supporter.

12. A fluid buffer arrangement comprising: a base means, a cylinder means disposed on said base means having a quantity of fluid disposed therein, plunger means slidably disposed in said cylinder means, means provided at one end of said plunger means for communicating said plunger means with said cylinder means, control means for selectively controlling said means for communicating, a hollow support means disposed at the other end of said plunger means, means provided in said hollow support means for communicating said plunger means with said hollow support means, fluid receiver means disposed on said base means separate from said cylinder means, and means disposed on said hollow support means for communicating said hollow support means with said fluid receiver means.

Claims

1. An oil buffer in which a tapered control rod is provided in a cylinder fixedly erected on a base and an oil injection hole arranged to allow passage of said control rod is provided at the bottom of a plunger arranged slidable in said cYlinder so that oil in said cylinder will be injected into said plunger through the space between said control rod and injection hole so as to produce a buffer action, and further characterized in that an oil check is provided at the inside top of said plunger, said oil check having the underside positioned above said injection hole so as to force back downwardly the oil which gushes out from said injection hole, and that air holes for ejecting air in the plunger are provided in the upper parts of said oil check.

9. An oil buffer according to claim 7, wherein said coil spring guide members are composed of hollow cylindrical bodies which are provided for oil passages, and wherein oil receiving means are provided on said base, said box-shaped supporter communicating with said oil receivers through said hollow cylindrical bodies.

10. An oil buffer according to claim 7, wherein an oil check is provided at the inside top of said plunger, said oil check having the underside thereof positioned above said injection hole so as to force back downwardly the oil which gushes out from said injection hole, and said oil check is provided with air holes for venting air in the plungeR, said air holes being communicated with said hole communicating the inside of said plunger with the inside of said box-shaped supporter.