GB2167494A - Hydraulic actuators for vehicle seats - Google Patents
Hydraulic actuators for vehicle seats Download PDFInfo
- Publication number
- GB2167494A GB2167494A GB08429777A GB8429777A GB2167494A GB 2167494 A GB2167494 A GB 2167494A GB 08429777 A GB08429777 A GB 08429777A GB 8429777 A GB8429777 A GB 8429777A GB 2167494 A GB2167494 A GB 2167494A
- Authority
- GB
- United Kingdom
- Prior art keywords
- cylinder
- piston
- hydraulic
- seat
- open end
- 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.)
- Granted
Links
- 230000007246 mechanism Effects 0.000 claims abstract description 30
- 230000003028 elevating effect Effects 0.000 claims abstract description 13
- 239000012530 fluid Substances 0.000 claims abstract description 10
- 238000004891 communication Methods 0.000 claims abstract description 6
- 230000006854 communication Effects 0.000 claims abstract description 6
- 238000007789 sealing Methods 0.000 claims abstract description 4
- 230000000694 effects Effects 0.000 abstract description 6
- RRLHMJHRFMHVNM-BQVXCWBNSA-N [(2s,3r,6r)-6-[5-[5-hydroxy-3-(4-hydroxyphenyl)-4-oxochromen-7-yl]oxypentoxy]-2-methyl-3,6-dihydro-2h-pyran-3-yl] acetate Chemical compound C1=C[C@@H](OC(C)=O)[C@H](C)O[C@H]1OCCCCCOC1=CC(O)=C2C(=O)C(C=3C=CC(O)=CC=3)=COC2=C1 RRLHMJHRFMHVNM-BQVXCWBNSA-N 0.000 description 3
- 230000003247 decreasing effect Effects 0.000 description 2
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 210000001699 lower leg Anatomy 0.000 description 1
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B15/00—Fluid-actuated devices for displacing a member from one position to another; Gearing associated therewith
- F15B15/08—Characterised by the construction of the motor unit
- F15B15/14—Characterised by the construction of the motor unit of the straight-cylinder type
- F15B15/16—Characterised by the construction of the motor unit of the straight-cylinder type of the telescopic type
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60N—SEATS SPECIALLY ADAPTED FOR VEHICLES; VEHICLE PASSENGER ACCOMMODATION NOT OTHERWISE PROVIDED FOR
- B60N2/00—Seats specially adapted for vehicles; Arrangement or mounting of seats in vehicles
- B60N2/02—Seats specially adapted for vehicles; Arrangement or mounting of seats in vehicles the seat or part thereof being movable, e.g. adjustable
- B60N2/0224—Non-manual adjustments, e.g. with electrical operation
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Aviation & Aerospace Engineering (AREA)
- Transportation (AREA)
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- General Engineering & Computer Science (AREA)
- Actuator (AREA)
Abstract
A vehicle seat is mounted on an hydraulic mechanism which allows the seat to be raised using hydraulic power, and to be lowered under the effect of its own weight. The hydraulic elevating mechanism comprises a cylinder (7) having a closed end (8) and a stepped cylindrical bore including a first portion (12) located adjacent an open end of the cylinder and a second portion (13) extending over a major part of the length of the cylinder, the second portion (13) having a larger diameter than the first portion (12). A piston (14) having a cylindrical shaft portion (15) extends through the open end of the cylinder and is in sliding sealing engagement with the first portion (12) of the cylinder. An enlarged head portion (17) of the piston (14) is in sliding contact with the second portion (13) of the cylinder. Spaced apart grooves (20) provide fluid communication from one side of the enlarged head to the other side. Preferably, a plurality of telescopic piston and cylinder sections are provided. <IMAGE>
Description
SPECIFICATION
Vehicle seats
This invention relates to seats for vehicles and more particularly to vehicle seats having hydraulic elevating mechanisms.
It is known to provide vehicle seats, for example the seats of lorries, with manually operated mechanical elevating mechanisms. Whilst such seats may function in a satisfactory manner for their particular purpose, there exists the need for a power operated elevating mechanism. Such a mechanism is required, for example, for special purpose vehicles where a large elevation is required, and for ordinary motor cars where frequent re-setting of the seat height may be required to accommodate different drivers.
Whilst the use of a hydraulically powered elevating mechanism has clear advantages, it has been found that there are numerous practical difficulties in producing a workable hydraulic mechanism. For example, the very limited space available between the seat and the floor of a motor car imposes a severe design limitation. In order to ensure sufficient rigidity in a hydraulic mechanism a large diameter piston and cylinder is indicated, but if a large diameter mechanism is used, the seat may not fall under its own weight, due to the low pressure generated within the cylinder, and the large area of seal contact.
We have, however, now devised a hydraulic seat mechanism which is compact, rigid, and which will allow a car seat to be raised using hydraulic power, and to be lowered under the effect of its own weight.
Accordingly, the present invention provides a hydraulic elevating mechanism for a vehicle seat comprising: a cylinder having a closed end, and open end, and a stepped cylindrical bore including a first portion located adjacent the open end of the cylinder and a second portion extending over a major part of the length of the cylinder, the second portion having a larger diameter than the first portion; a piston having a cylindrical shaft portion which extends through the open end of the cylinder and is in sliding sealing engagement with the first portion of the cylinder, and an enlarged head
portion which is in sliding contact with the second
portion of the cylinder; a fluid passage means providing fluid communication from one side of the enlarged head to the other side thereof; means for securing one of the piston and the cylinder to a ve
hicle body; and means for securing the other of the piston and the cylinder to a vehicle seat such that admission or pressurised hydraulic fluid to the cylinder causes elevation of the seat.
The invention will be better understood and advantages of the invention will become clear from the following description of a preferred embodi
ment thereof, by way of example only, reference
being had to the accompanying drawing, wherein:
Figure 1 shows a vehicle fitted with a hydraulic seat elevating mechanism;
Figure 2 shows, on a larger scale, the hydraulic mechanism of the vehicle of Figure 1; and
Figure 3 shows the hydraulic mechanism of Figure 2 in its fully closed configuration.
Referring firstly to Figure 1 there is shown a vehicle 1 having a driver's seat 2 provided with a hydraulic elevating mechanism 3. The elevating mechanism 3 provides sufficient lift to enable a driver seated on the seat 2 to project through an open sunshine roof 4. Such an arrangement may be particularly advantageous in specialist vehicles such as police vehicles, vehicles driven by photographers, vehicles driven by race goers, and in general vehicles driven by those who wish to have the facility for an enhanced view from their vehicle.
In the fully lowered position of the seat 2 (shown in broken lines) the seat is at a normal driving height. By partially elevating the mechanism 3 the seat may be positioned at any point intermediate its fully raised and fully lowered positions so that, in effect, the driving height of the seat can be adjusted to meet the wishes of the particular driver.
The elevating mechanism 3 comprises a multistage hydraulic ram 5 (shown in more detail in Figures 2 and 3) surrounded by a collapsible dustproof gaiter 6. Hydraulic power for the mechanism 3 is provided by a suitable engine driven or electrically driven hydraulic pump.
Referring now to Figures 2 and 3 the ram 5 is shown respectively in its fully extended and fully retracted configurations. The ram comprises a cylinder 7 closed at one end by a base plate 8 in which is formed a hydraulic connection 9 communicating with the interior of the cylinder 7. In use, the base plate 8 is secured to the floor pan of a vehicle by suitable means (not shown) the cylinder 7 includes an open end 10 and a stepped cylindrical bore 11 comprising a first portion 12 adjacent the open end 10 and a second portion 13 extending over a major part of the length of the cylinder from the first portion 12 to the base plate 8. A piston 14 includes a shaft portion 15 which is a close tolerance fit within the first portion 12 of the bore 11.
An O-ring seal 16 provides sealing between the cylinder and the piston. The piston 14 also includes an enlarged head portion 17 which is a close sliding fit within the second portion 13 of the bore 11.
The close tolerances of the sliding fits between the portions 12 and 15 on the one hand and 13 and 17 on the other hand, combined with the relatively large diameter of the cylinder 7, ensures that rocking of the piston relative to the cylinder is minimal.
In the fully extended configuration (as shown in
Figure 2) shoulders 18 and 19 formed respectively on the cylinder and piston are held in firm engagement by hydraulic pressure within the cylinder, thereby reducing still further the possibility of relative rocking movement between the piston and the cylinder. This is most important since any such rocking movement will result in swaying of the seat 2.
A plurality of axially extending circumferentially spaced apart grooves 20 are formed in the head portion 17 of the piston 14 in order to provide a communication from one side of the head portion 17 to the other side thereof, i.e. to provide commu nication between the interior of the cylinder 17 and the annular space 21 which exists between the second portion 13 of the stepped bore 11 and the shaft portion 15 of the piston 14 when the ram is not fully extended. These grooves are most important in allowing hydraulic fluid to flow relatively easily past the head portion 17 during both extension and retraction of the ram. This is most important, particularly during retraction of the ram, since there must be minimal restraint against retraction if the seat is to fall under the influence of its own weight.This is because the relatively light weight of the seat, compared with the relatively large diameter of the cylinder means that a very small hydraulic back pressure will prevent falling of the seat. Any additional impediment of the seat is accordingly highly undesirable and must be avoided if the seat is to fall satisfactorily under the influence of its own weight.
Similarly, with a view to reducing to a minimum resistance to hydraulic fluid flow during retraction of the ram, spaced apart grooves 22 are provided in the end face of the piston, and grooves 23 are provided in the base plate 8.
In the case of the preferred embodiment a multistage ram 5 is used and includes additional pistons 24, 25, 26 and 27, with the piston 14 acting as a cylinder for piston 24, piston 24 acting as a cylinder for piston 25, and so on. Each piston 24-27 is generally similar to piston 14, except that it will be noted that the axial extent of the head portions 2831 of the pistons 24-27 respectively progressively increases. Whilst this has the effect of progressively decreasing the amount of lift provided by each piston, it is nonetheless a desirable feature since it improves stability of the ram by offsetting the effect of progressively decreasing diameter.In other words, if all the head portions were to have the same axial extent, each stage of the ram would allow progressively more rocking movement because of the reducing diameter of the stages, assuming all components were manufactured to the same tolerances and with the same clearances.
The progressively increasing axial extent of the head portions offsets this effect and ensures a particularly rigid ram assembly.
A head plate 32 is secured to the piston 27, the head plate being in turn secured to the frame of the seat 2. A hydraulic bleed screw 33 is also provided in the piston 27.
Each piston is provided with a circlip 34 secured by suitable adhesive within a groove formed adjacent the upper end of the piston shaft. As each stage of the ram becomes fully retracted the circlips 34 seat against shoulders provided in the next adjacent lower piston to provide a direct mechanical transfer of thrust load.
An embodiment of the invention manufactured in accordance with the drawings has been tested and has been found to be satisfactory for raising a vehicle seat by a total amount of 558 mm. Hydraulic power has been satisfactorily supplied by means of an electric hydraulic pump driven from a 12 volt car battery, and lowering of the seat occurs merely by providing a large-bore return pipe from the connection 9 to reservoir.
Whilst for specialist vehicle applications a multistage ram as shown is preferred, it will be appreciated that where a total lift of no more than, say, 120 mm is required, a single stage ram consisting of a single cylinder and single piston may be used.
Such an arrangement is particularly suited for use in conventional salon cars in order to provide powered raising and lowering of a driver's seat.
Claims (10)
1. A hydraulic elevating mechanism for a vehicle seat comprising: a cylinder having a closed end, an open end, and a stepped cylindrical bore including a first portion located adjacent the open end of the cylinder and a second portion extending over a major part of the length of the cylinder, the second portion having a larger diameter than the first portion; a piston having a cylindrical shaft portion which extends through the open end of the cylinder and is in sliding sealing engagement with the first portion of the cylinder, and an enlarged head portion which is in sliding contact with the second portion of the cylinder; fluid passage means providing fluid communication from one side of the enlarged head to the other side thereof; means for securing one of the piston and the cylinder to a vehicle body; and means for securing another of the piston and the cylinder to a vehicle seat such that admission of pressurised hydraulic fluid to the cylinder causes elevation of the seat.
2. A mechanism as claimed in claim 1, comprising a plurality of pistons and cylinders so arranged that the piston of one cylinder is hollow to act also as a cylinder for a succeeding piston.
3. A mechanism as claimed in claim 2, wherein the axial extent of the head portion is greater for each succeeding piston.
4. A mechanism as claimed in any one of the preceding claims, wherein the head portion of the or each piston is provided circumferentially with one or more axially extending grooves to permit fluid communication from one side to the other of the or each head portion.
5. A mechanism as claimed in claim 4, wherein there are a plurality of axially extending grooves spaced around the circumference of the or each piston head portion.
6. A mechanism as claimed in claim 5, wherein the grooves are spaced equally around the circumference.
7. A mechanism as claimed in any one of the preceding claims, wherein the cylindrical shaft portion of the or each piston is provided adjacent its outer end with abutment means to transfer load to a shoulder means of the or the respective cylinder when in retracted condition.
8. A mechanism as claimed in any one of the preceding claims, further comprising a source of hydraulic power.
9. A mechanism as claimed in claim 8, wherein the power source is an electric hydraulic pump.
10. A hydraulic elevating mechanism for a vehicle seat substantially as described herein with reference to the accompanying drawings.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB08429777A GB2167494B (en) | 1984-11-26 | 1984-11-26 | Hydraulic actuators for vehicle seats |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB08429777A GB2167494B (en) | 1984-11-26 | 1984-11-26 | Hydraulic actuators for vehicle seats |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB8429777D0 GB8429777D0 (en) | 1985-01-03 |
| GB2167494A true GB2167494A (en) | 1986-05-29 |
| GB2167494B GB2167494B (en) | 1988-05-05 |
Family
ID=10570259
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB08429777A Expired GB2167494B (en) | 1984-11-26 | 1984-11-26 | Hydraulic actuators for vehicle seats |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2167494B (en) |
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3909370A1 (en) * | 1989-03-22 | 1990-09-27 | Harry Gielnik | Double-acting telescopic cylinder with mechanical retraction |
| GB2357806A (en) * | 1999-12-02 | 2001-07-04 | Trevor John Honour | Load bearing props |
| GB2410782A (en) * | 2004-02-09 | 2005-08-10 | Autoliv Dev | Improvements in or relating to a safety device |
| US7137330B2 (en) | 2003-10-22 | 2006-11-21 | Lear Corporation | Vehicle seat adjustment with actuator isolation valves |
| US7152402B2 (en) | 2003-10-22 | 2006-12-26 | Lear Corporation | Hydraulic vehicle seat adjustment control valve assembly |
| US7182385B2 (en) | 2003-12-10 | 2007-02-27 | Lear Corporation | Vehicle seat track with hydraulic actuator |
| US7226105B2 (en) | 2003-10-22 | 2007-06-05 | Lear Corporation | Hydraulic vehicle seat adjustment with system protection valve |
| US7229133B2 (en) | 2003-12-19 | 2007-06-12 | Lear Corporation | Vehicle seat adjustment system including an occupant protection adjustment |
| US7290834B2 (en) | 2003-10-22 | 2007-11-06 | Lear Corporation | Hydraulic vehicle seat adjustment system |
| US7506931B2 (en) | 2004-07-01 | 2009-03-24 | Lear Corporation | Hydraulically powered folding vehicle seat fold |
| US10017363B2 (en) * | 2016-01-29 | 2018-07-10 | Manitou Italia S.R.L. | Telescopic arm for self-propelled operating machines |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB612763A (en) * | 1946-06-01 | 1948-11-17 | Henry Leslie Brooke | Hydro-pneumatic lifting jack |
| GB831000A (en) * | 1957-11-15 | 1960-03-23 | Anthony Co | Improvements relating to the reinforcement of cylinders subjected to internal fluid pressure |
| GB1045917A (en) * | 1962-10-02 | 1966-10-19 | Eaton Yale & Towne | Hydraulic lift truck |
| GB1180767A (en) * | 1967-11-02 | 1970-02-11 | Eagle Eng Co Ltd | Improvements relating to multiple draw piston and cylinder units. |
| GB2087977A (en) * | 1980-11-11 | 1982-06-03 | Partek Ab | Bearing arrangement or a telescopic cylinder |
| GB2119019A (en) * | 1982-02-26 | 1983-11-09 | Montan Hydraulik Gmbh & Co Kg | A multi-stage hydraulic telescopic cylinder |
-
1984
- 1984-11-26 GB GB08429777A patent/GB2167494B/en not_active Expired
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB612763A (en) * | 1946-06-01 | 1948-11-17 | Henry Leslie Brooke | Hydro-pneumatic lifting jack |
| GB831000A (en) * | 1957-11-15 | 1960-03-23 | Anthony Co | Improvements relating to the reinforcement of cylinders subjected to internal fluid pressure |
| GB1045917A (en) * | 1962-10-02 | 1966-10-19 | Eaton Yale & Towne | Hydraulic lift truck |
| GB1180767A (en) * | 1967-11-02 | 1970-02-11 | Eagle Eng Co Ltd | Improvements relating to multiple draw piston and cylinder units. |
| GB2087977A (en) * | 1980-11-11 | 1982-06-03 | Partek Ab | Bearing arrangement or a telescopic cylinder |
| GB2119019A (en) * | 1982-02-26 | 1983-11-09 | Montan Hydraulik Gmbh & Co Kg | A multi-stage hydraulic telescopic cylinder |
Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3909370A1 (en) * | 1989-03-22 | 1990-09-27 | Harry Gielnik | Double-acting telescopic cylinder with mechanical retraction |
| GB2357806A (en) * | 1999-12-02 | 2001-07-04 | Trevor John Honour | Load bearing props |
| US7137330B2 (en) | 2003-10-22 | 2006-11-21 | Lear Corporation | Vehicle seat adjustment with actuator isolation valves |
| US7152402B2 (en) | 2003-10-22 | 2006-12-26 | Lear Corporation | Hydraulic vehicle seat adjustment control valve assembly |
| US7226105B2 (en) | 2003-10-22 | 2007-06-05 | Lear Corporation | Hydraulic vehicle seat adjustment with system protection valve |
| US7290834B2 (en) | 2003-10-22 | 2007-11-06 | Lear Corporation | Hydraulic vehicle seat adjustment system |
| US7182385B2 (en) | 2003-12-10 | 2007-02-27 | Lear Corporation | Vehicle seat track with hydraulic actuator |
| US7229133B2 (en) | 2003-12-19 | 2007-06-12 | Lear Corporation | Vehicle seat adjustment system including an occupant protection adjustment |
| GB2410782A (en) * | 2004-02-09 | 2005-08-10 | Autoliv Dev | Improvements in or relating to a safety device |
| GB2410782B (en) * | 2004-02-09 | 2007-07-11 | Autoliv Dev | Improvements in or relating to a safety device |
| US7506931B2 (en) | 2004-07-01 | 2009-03-24 | Lear Corporation | Hydraulically powered folding vehicle seat fold |
| US10017363B2 (en) * | 2016-01-29 | 2018-07-10 | Manitou Italia S.R.L. | Telescopic arm for self-propelled operating machines |
Also Published As
| Publication number | Publication date |
|---|---|
| GB8429777D0 (en) | 1985-01-03 |
| GB2167494B (en) | 1988-05-05 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 19951126 |