US4516469A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electric hydraulic controll device for a construction vehicle
Assignee: Komatsu Ltd
•
Filing: 1982-05-25
•
Granted: 1985-05-14
•
Expires: 2002-05-25
Abstract
Abstract An electric hydraulic control device for controlling hydraulic cylinders of work tools in a construction vehicle, in which control valves of the hydraulic cylinders are controlled in two ways. For some work tools which need not be controlled smoothly and finely, the corresponding control valves are controlled directly by an electric signal outputted according to the position of the operation levers, and for other work tools which must be controlled smoothly and finely, the corresponding control valves are controlled through an electric servo mechanism which is operated by an electric signal representative of the amount by which the operation lever is manipulated. In addition, there is provided a detector for detecting as to whether the transmission lever is in the locked condition, and electric systems of all of the control valves are rendered inoperative when the transmission lever is in the locked condition.
Inventors
- 👤 Yoshito Sato
- 👤 Tokuhiro Yato
- 👤 Hidemi Maeo
- 👤 Yoshio Tsutsumi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 21:09
CPC Classifications
F; F15; F15B; F15B21/00; F15B21/08; E; E02; E02F; E02F3/00; E02F3/04; E02F3/96; E02F3/961; E02F5/00; E02F5/30; E02F5/32; E02F9/00; E02F9/20; E02F9/2004; E02F9/2025; G; G05; G05B; G05B2219/00; G05B2219/30; G05B2219/36; G05B2219/36429; G05B2219/41; G05B2219/41302; G05B2219/41318; Y; Y10; Y10T; Y10T74/00; Y10T74/21; Y10T74/2133; Y10T74/2136; Y10T74/2142; Y10T74/2144; Y10T74/2147
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
201 words
An electric hydraulic control device for a construction vehicle comprising: first signal generating means for generating a first electric signal corresponding to the operating position of an operation lever according to the operation of said operation lever; a first electric hydraulic control system for controlling a first direction control valve by means of said first electric signal, and supplying hydraulic fluid to a first hydraulic cylinder for driving a work tool according to the operation of said direction control valve; second signal generating means for generating a second electric signal corresponding to the stroke of said operation lever according to the operation of said operation lever; and a second electric hydraulic control system for controlling the position of a spool of a second control valve by means of a difference between said second electric signal and a third electric signal applied from an electric servo mechanism and corresponding to the position of said spool of said second control valve, said electric servo mechanism having a stepping motor driven in response to said difference, a stepping cylinder, and a differential transformer, and controlling said work tool, or the specific operation of said work tool according to the operation of said control valve.
Claim 2
Dependent Claim
201 words
An electric hydraulic control device for a construction vehicle comprising: first signal generating means for generating a first electric signal corresponding to the operating position of an operation lever according to the operation of said operation lever; a first electric hydraulic control system for controlling a first direction control valve by means of said first electric signal, and supplying hydraulic fluid to a first hydraulic cylinder for driving a work tool according to the operation of said direction control valve; second signal generating means for generating a second electric signal corresponding to the stroke of said operation lever according to the operation of said operation lever; and a second electric hydraulic control system for controlling the position of a spool of a second control valve by means of a difference between said second electric signal and a third electric signal applied from an electric servo mechanism and corresponding to the position of said spool of said second control valve, said electric servo mechanism having a stepping motor driven in response to said difference, a stepping cylinder, and a differential transformer, and controlling said work tool, or the specific operation of said work tool according to the operation of said control valve.
Claim 3
Dependent Claim
74 words
An electric hydraulic control device as defined in claim 1 further comprising: a transmission lever; a lock lever for locking said transmission lever during a period when said transmission lever is in the neutral position; a detector means for detecting the placement of said lock lever in the lock position; and break means for breaking electric circuits of said first and second electric hydraulic control systems by means of the output of said detector.
Claim 4
Dependent Claim
46 words
An electric hydraulic control device as defined in claim 1, wherein said construction vehicle is a bulldozer, and said first hydraulic cylinder tilts the blade of said bulldozer and said second hydraulic cylinder raises and lowers said blade in response to the supply of hydraulic fluid.
Claim 5
Dependent Claim
29 words
An electric hydraulic control device as defined in claim 1, wherein said spool is coupled to said stepping motor, and said stepping cylinder is hydraulically controlled by said spool.
Claim 6
Dependent Claim
184 words
An electric hydraulic control device for a construction vehicle comprising: first signal generating means for generating a first electric signal corresponding to the placement of a first operation lever in one of two predetermined positions; a first electric hydraulic control system for controlling a first control valve by means of said first electric signal, and for supplying hydraulic fluid to a first hydraulic cylinder for controlling the movement of a first work tool along a first degree of freedom; second signal generating means for generating a second electric signal corresponding to the stroke of said first operation lever during operation; and a second electric hydraulic control system for controlling the position of a spool of a second control valve by means of a difference between said second electric signal and a third electric signal formed in an electric servo mechanism and corresponding to the position of said spool, said electric servo mechanism having a stepping motor driven in response to said difference, a stepping cylinder, and a differential transformer, and controlling the movement of said first work tool along a second degree of freedom.
Claim 7
Dependent Claim
184 words
An electric hydraulic control device for a construction vehicle comprising: first signal generating means for generating a first electric signal corresponding to the placement of a first operation lever in one of two predetermined positions; a first electric hydraulic control system for controlling a first control valve by means of said first electric signal, and for supplying hydraulic fluid to a first hydraulic cylinder for controlling the movement of a first work tool along a first degree of freedom; second signal generating means for generating a second electric signal corresponding to the stroke of said first operation lever during operation; and a second electric hydraulic control system for controlling the position of a spool of a second control valve by means of a difference between said second electric signal and a third electric signal formed in an electric servo mechanism and corresponding to the position of said spool, said electric servo mechanism having a stepping motor driven in response to said difference, a stepping cylinder, and a differential transformer, and controlling the movement of said first work tool along a second degree of freedom.
Claim 8
Dependent Claim
74 words
An electric hydraulic control device as defined in claim 5 further comprising: a transmission lever; a lock lever for locking said transmission lever during a period when said transmission lever is in its neutral position; a detector means for detecting the placement of said lock lever in the lock position; and break means for breaking electric circuits of said first and second electric hydraulic control systems by means of the output of said detector.
Claim 9
Dependent Claim
76 words
An electric hydraulic control device as defined in claim 5, further comprising: third signal generating means for generating a fourth electric signal corresponding to the placement of a second operation lever in one of two predetermined positions; and a third electric hydraulic control system for controlling a third control valve by means of said fourth electric signal, and for supplying hydraulic fluid to a third hydraulic cylinder for controlling the movement of a second work tool.
References Cited (Backward Citations)
US2175799A
Cited
US2643515A
Cited
US3768367A
Cited
US3818926A
Cited
US3945206A
Cited
US4281526A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-05-13 | 1988-11-12 | 1989-05-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-05-13 | 1992-11-12 | 1993-05-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-05-13 | 1996-11-12 | 1997-05-14 | $7700.00 | Window Closed / Lapsed |