CA1155199A - Winch safety control - Google Patents
Winch safety controlInfo
- Publication number
- CA1155199A CA1155199A CA000363600A CA363600A CA1155199A CA 1155199 A CA1155199 A CA 1155199A CA 000363600 A CA000363600 A CA 000363600A CA 363600 A CA363600 A CA 363600A CA 1155199 A CA1155199 A CA 1155199A
- Authority
- CA
- Canada
- Prior art keywords
- port
- fluid
- valve
- conduit
- motor
- 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
Abstract
WINCH SAFETY CONTROL
ABSTRACT OF THE DISCLOSURE
A motor of the type having a low speed ratio and a high speed ratio is disclosed. A fluid port in said motor corresponds to each of said speed ratios and a port conduit extends from each respective port. A
single valve is operatively connected to all of said port conduits and is spring biased to supply fluid to the low speed ratio. A solenoid operatively associated with the valve controls the shifting of the valve to supply fluid under pressure to a selective one of said port conduits so that the motor is placed in the speed ratio corresponding to the port receiving the pressurized fluid. In the preferred embodiment which describes a two-speed fluid actuated motor for a winch on a crane, a first fluid pressure sensor is placed in the low speed port conduit and at a predetermined pressure level in the low speed port conduit sends out an impulse to prevent the solenoid from being energized to shift the valve to supply pressurized fluid to the high speed ratio. A second sensor is placed in the high speed port conduit and sends out an impulse to disable the electrical circuit of the solenoid to allow the valve to return to a position to supply fluid to the low speed ratio port when the pressure in the high speed port conduit is above a predetermined level.
ABSTRACT OF THE DISCLOSURE
A motor of the type having a low speed ratio and a high speed ratio is disclosed. A fluid port in said motor corresponds to each of said speed ratios and a port conduit extends from each respective port. A
single valve is operatively connected to all of said port conduits and is spring biased to supply fluid to the low speed ratio. A solenoid operatively associated with the valve controls the shifting of the valve to supply fluid under pressure to a selective one of said port conduits so that the motor is placed in the speed ratio corresponding to the port receiving the pressurized fluid. In the preferred embodiment which describes a two-speed fluid actuated motor for a winch on a crane, a first fluid pressure sensor is placed in the low speed port conduit and at a predetermined pressure level in the low speed port conduit sends out an impulse to prevent the solenoid from being energized to shift the valve to supply pressurized fluid to the high speed ratio. A second sensor is placed in the high speed port conduit and sends out an impulse to disable the electrical circuit of the solenoid to allow the valve to return to a position to supply fluid to the low speed ratio port when the pressure in the high speed port conduit is above a predetermined level.
Description
~5t~ 99 WINCH SAFETY CONTROL
BACKGROUND_OF THE INVENTION
This invention pertains to fluid actuated multi-speed motors with electronic pressure sensitive override controls and more specifically to a hydrostatic motor for a two-speed winch which is hydraulically actuated to shift from one speed ratio to another.
It has been recognized in the prior art that it would be desirable to have an override system to shift a hydraulically actuated multi-speed ratio motor to a lower speed ratio when pressure in the hydraulically actuated con~rols reaches a certain predetermined level. However, in the prior art known to the inventor attempts to provide a hydraulic override system were not satisfactory because the hydraulically actuated controls constantly shifted or hunted between speed ratios at certain line pressures. Therefore, most hydraulically actuated motor controls of the prior art did not employ an override system but relied on safety check valves to open and lower hydraulic pressure in the hydraulically actuated controls when the hydraulic pressure reached a predetermined unsafe level. A major disadvantage in the prior art hydraulic system is that the motor is completely shut down at high hydraulic pressures. In motors for crane winches a shutdown could result in loads being sus-pended in mid-air until the motor is reset.
This invention solves the previously mentioned problems and dis-advantages of the prior art by providing low and high speed ports in the motor corresponding to low and high speed ratios and a port conduit extending from each respective port. A valve operatively connected with both conduits can be selectively positioned to supply fluid under pressure to a selective one of the port conduits so that the motor is placed in a speed ratio corresponding to the port receiving fluid from the selected port conduit. The valve is spring biased to supp1y fluid to the low speed ratio. A selectively actuated solenoid operatively associated with the valve positions the valve to supply fluid to the l ~k -- 115S~99 high speed port to place the motor in the high speed ratio. However, when fluid pressure reaches a predetermined level for the selected port conduit a pressure sensor placed in the selected port conduit will send an impulse to disable the solenoid, thus positioning or maintaining the valve in a position for supplying fluid to the low speed port conduit corresponding to the low speed port.
FIGURE 1 is a schematic diagram of the hydraulic and electrical circuitry employed in the preferred embodiment of the present invention.
In FIG. 1, a fluid controlled two-speed ratio motor 14 of a con-ventional hydrostatic motor-pump system is schematically illustrated.
The motor 14 could commonly be found in a winch for use on a crane.
Hydraulic fluid goes from a pump (not shown) through load conduit 16 to motor 14 and then returns to the pump through return conduit 18.
Hydraulic fluid from a conduit 20, which branches from load conduit 16, is supplied to low speed port 22 or high speed port 24 by selective adjustment of directional control valve 26. Spring 28 urges directional control valve 26 to a low speed port actuation position 27 shown in FIG. 1 wherein conduit 20 supplies fluid through a low speed supply section 25 of directional control valve 26 and low speed port conduit 30 to low speed port 22 to place the motor in a low speed rat~o. In the low speed ratio, hydraulic fluid from the flu~d controls (not shown) in motor 14 is returned to conduit 18 through h~gh speed port 24, high speed port conduit 32, a low speed return section 31, and motor dis-charge conduit 19.
To place the motor 14 in a high speed ratin, fluid control valve 26 is shifted rightward from the low speed actuation position 27 shown in FIG. 1 to a high speed actuation position 29 to provide hydraulic fluid from conduit 20 through high speed supply section 33 of valve 26 and conduit 32 to high speed port 24. Hydraulic fluid returns via low speed port 22, low speed port conduit 30, high speed return section 35 of valve 26, and motor discharge conduit 19 to return conduit 18 for recirculation through the pump.
High speed switch 36 (which is preferably a push button) of an electrical control circuit 34 shown in the upper portion of FIG. 1 is manually closed to energize solenoid coil 38 to shift directional control valve 26 from its FIG. 1 low speed ratio port actuatation position 27 to the rightward high speed port actuation position 29.
Additionally, relay circuit coil 40 is also energized when switch 36 is closed. Normally spaced-apart contacts 42 are closed by the energiza-tion of relay circuit coil 40 for maintaining solenoid coil 38 in an activated condition to retain the directional control valve 26 in the high speed position 29 until either a low speed switch 37 is manually depressed or the pressure in high speed port conduit 32 exceeds a certain predetermined pressure level (4000 psi for the above-discussed winch application).
Pressure sensor 44 which is preferably a spring biased piston (not shown) is interposed in and responsive to fluid pressure in high speed port conduit 32 and is fluid connected to a high speed pressure switch 46 of circuit 34 by high speed pilot conduit 45. High speed pressure switch 46 is urged by spring 48 to a closed contact position. When the motor 14 is in its high speed ratio and the pressure in conduit 32 exceeds the predetermined pressure level, high speed pressure switch 46 switches to an open positlon against the blas of a sprlng 48 and thus de-energlzes solenold coll 38 and relay clrcu~t coll 40 to allow sprlng 28 to shift dlrectlonal control valve 26 back to lts FIG. 1 low speed ratio position 27 and to open contacts 42. After high speed pressure switch 46 has opened in response to an impulse from sensor 44, further manual actuatlon of high speed switch 36 will not energize the circuit since the pressure in conduit 32 will not decrease to deactivate sensor 44 until the load on the motor 14 which caused the increased pressure on the conduit line is released.
In the preferred embodiment the hydraulic piston of sensor 44 in line 32 which is normally spring biased to a closed position will shift 11~i5~99 under hydraulic pressure to compress the piston spring and increase the hydraulic pressure in pilot line 45 to cause high speed pressure switch 46 to switch to an open position resisting the bias of spring 48 in switch 46.
Pressure sensor 50 which is also preferably a spring biased piston (not shown) is interposed in low speed port conduit 30 and responsive to fluid pressure and sensor 50 is fluid connected to a low speed pressure switch 52 of circuit 34 by low speed pilot conduit 54. Low speed pressure switch 52 is urged by a spring 53 to a closed contact position.
When the motor 14 is in its low speed ratio and the pressure in conduit 30 exceeds a certain predetermined pressure level (preferably 1800 psi in the above-discussed preferred embodiment), low speed pressure switch 52 switches to an open position to break circuit 34 and therefore actuation of high speed contact switch 36 will not energize solenoid coil 38 or relay circuit coil 40 to shift the directional control valve to its high speed port actuation position 29.
In the preferred embodiment the hydraulic piston in line 30, which is normally spring biased to a closed position, will shift under hydraulic pressure to compress the piston spring (not shown) of sensor 50 and increase the hydraulic pressure in pilot line 54 to cause low speed pressure switch 52 to switch to an open position resisting the bias of the spring 53 associated therewith. Once low speed pressure swftch 52 has opened, manual actuation of high speed switch 36 will not energlze solenoid coil 38 to shift directional control valve 26 to its high speed port actuation position 29 since the pressure in conduit 30 will not decrease below a predetermined level to allow the hydraulic piston of sensor SO to return to its normally closed position until the load on the motor 14 which caused the increased pressure on the conduit line 30 is released.
It will be appreciated that numerous modifications may be made without departing from the scope of this invention. For example, the llS5~19 hydraulic sensors 44 and 50, high speed and low speed pilot hydraulic conduit lines 45 and 54 and pressure switches 46 and 52 respectively could be replaced by a microprocessor and pressure transducer(s) if desired. Additionally, the motor employed in this invention could be of any power-driven type which utilized fluid controls to change from one speed ratio to another. Although hydraulic fluid controls are disclosed in the preferred embodiment, pneumatic or other types of fluid controls could also be used. Moreover, although the preferred embodiment contem-plated for the present invention is used on the motor of a winch con-nected with a crane, the instant invention is not limited to the present application but could be used whenever it is desirable to monitor and control the fluid pressure of the fluid controls of a motor.
From the foregoing it is believed that those familiar with the art will readily recognize and appreciate the novel concepts and features of the present invention. Obviously, while the invention has been des-cribed in relation to only a preferred embodiment, numerous variations, changes, and substitutions of equivalents will present themselves to persons skilled in the art and may be made without necessarily departing from the scope of the principles of this invention. As a result, the embodiment described herein is subject to various modlfications, changes, and the like wlth the scope of thls lnventlon belng determlned solely by reference to the claims appended hereto.
BACKGROUND_OF THE INVENTION
This invention pertains to fluid actuated multi-speed motors with electronic pressure sensitive override controls and more specifically to a hydrostatic motor for a two-speed winch which is hydraulically actuated to shift from one speed ratio to another.
It has been recognized in the prior art that it would be desirable to have an override system to shift a hydraulically actuated multi-speed ratio motor to a lower speed ratio when pressure in the hydraulically actuated con~rols reaches a certain predetermined level. However, in the prior art known to the inventor attempts to provide a hydraulic override system were not satisfactory because the hydraulically actuated controls constantly shifted or hunted between speed ratios at certain line pressures. Therefore, most hydraulically actuated motor controls of the prior art did not employ an override system but relied on safety check valves to open and lower hydraulic pressure in the hydraulically actuated controls when the hydraulic pressure reached a predetermined unsafe level. A major disadvantage in the prior art hydraulic system is that the motor is completely shut down at high hydraulic pressures. In motors for crane winches a shutdown could result in loads being sus-pended in mid-air until the motor is reset.
This invention solves the previously mentioned problems and dis-advantages of the prior art by providing low and high speed ports in the motor corresponding to low and high speed ratios and a port conduit extending from each respective port. A valve operatively connected with both conduits can be selectively positioned to supply fluid under pressure to a selective one of the port conduits so that the motor is placed in a speed ratio corresponding to the port receiving fluid from the selected port conduit. The valve is spring biased to supp1y fluid to the low speed ratio. A selectively actuated solenoid operatively associated with the valve positions the valve to supply fluid to the l ~k -- 115S~99 high speed port to place the motor in the high speed ratio. However, when fluid pressure reaches a predetermined level for the selected port conduit a pressure sensor placed in the selected port conduit will send an impulse to disable the solenoid, thus positioning or maintaining the valve in a position for supplying fluid to the low speed port conduit corresponding to the low speed port.
FIGURE 1 is a schematic diagram of the hydraulic and electrical circuitry employed in the preferred embodiment of the present invention.
In FIG. 1, a fluid controlled two-speed ratio motor 14 of a con-ventional hydrostatic motor-pump system is schematically illustrated.
The motor 14 could commonly be found in a winch for use on a crane.
Hydraulic fluid goes from a pump (not shown) through load conduit 16 to motor 14 and then returns to the pump through return conduit 18.
Hydraulic fluid from a conduit 20, which branches from load conduit 16, is supplied to low speed port 22 or high speed port 24 by selective adjustment of directional control valve 26. Spring 28 urges directional control valve 26 to a low speed port actuation position 27 shown in FIG. 1 wherein conduit 20 supplies fluid through a low speed supply section 25 of directional control valve 26 and low speed port conduit 30 to low speed port 22 to place the motor in a low speed rat~o. In the low speed ratio, hydraulic fluid from the flu~d controls (not shown) in motor 14 is returned to conduit 18 through h~gh speed port 24, high speed port conduit 32, a low speed return section 31, and motor dis-charge conduit 19.
To place the motor 14 in a high speed ratin, fluid control valve 26 is shifted rightward from the low speed actuation position 27 shown in FIG. 1 to a high speed actuation position 29 to provide hydraulic fluid from conduit 20 through high speed supply section 33 of valve 26 and conduit 32 to high speed port 24. Hydraulic fluid returns via low speed port 22, low speed port conduit 30, high speed return section 35 of valve 26, and motor discharge conduit 19 to return conduit 18 for recirculation through the pump.
High speed switch 36 (which is preferably a push button) of an electrical control circuit 34 shown in the upper portion of FIG. 1 is manually closed to energize solenoid coil 38 to shift directional control valve 26 from its FIG. 1 low speed ratio port actuatation position 27 to the rightward high speed port actuation position 29.
Additionally, relay circuit coil 40 is also energized when switch 36 is closed. Normally spaced-apart contacts 42 are closed by the energiza-tion of relay circuit coil 40 for maintaining solenoid coil 38 in an activated condition to retain the directional control valve 26 in the high speed position 29 until either a low speed switch 37 is manually depressed or the pressure in high speed port conduit 32 exceeds a certain predetermined pressure level (4000 psi for the above-discussed winch application).
Pressure sensor 44 which is preferably a spring biased piston (not shown) is interposed in and responsive to fluid pressure in high speed port conduit 32 and is fluid connected to a high speed pressure switch 46 of circuit 34 by high speed pilot conduit 45. High speed pressure switch 46 is urged by spring 48 to a closed contact position. When the motor 14 is in its high speed ratio and the pressure in conduit 32 exceeds the predetermined pressure level, high speed pressure switch 46 switches to an open positlon against the blas of a sprlng 48 and thus de-energlzes solenold coll 38 and relay clrcu~t coll 40 to allow sprlng 28 to shift dlrectlonal control valve 26 back to lts FIG. 1 low speed ratio position 27 and to open contacts 42. After high speed pressure switch 46 has opened in response to an impulse from sensor 44, further manual actuatlon of high speed switch 36 will not energize the circuit since the pressure in conduit 32 will not decrease to deactivate sensor 44 until the load on the motor 14 which caused the increased pressure on the conduit line is released.
In the preferred embodiment the hydraulic piston of sensor 44 in line 32 which is normally spring biased to a closed position will shift 11~i5~99 under hydraulic pressure to compress the piston spring and increase the hydraulic pressure in pilot line 45 to cause high speed pressure switch 46 to switch to an open position resisting the bias of spring 48 in switch 46.
Pressure sensor 50 which is also preferably a spring biased piston (not shown) is interposed in low speed port conduit 30 and responsive to fluid pressure and sensor 50 is fluid connected to a low speed pressure switch 52 of circuit 34 by low speed pilot conduit 54. Low speed pressure switch 52 is urged by a spring 53 to a closed contact position.
When the motor 14 is in its low speed ratio and the pressure in conduit 30 exceeds a certain predetermined pressure level (preferably 1800 psi in the above-discussed preferred embodiment), low speed pressure switch 52 switches to an open position to break circuit 34 and therefore actuation of high speed contact switch 36 will not energize solenoid coil 38 or relay circuit coil 40 to shift the directional control valve to its high speed port actuation position 29.
In the preferred embodiment the hydraulic piston in line 30, which is normally spring biased to a closed position, will shift under hydraulic pressure to compress the piston spring (not shown) of sensor 50 and increase the hydraulic pressure in pilot line 54 to cause low speed pressure switch 52 to switch to an open position resisting the bias of the spring 53 associated therewith. Once low speed pressure swftch 52 has opened, manual actuation of high speed switch 36 will not energlze solenoid coil 38 to shift directional control valve 26 to its high speed port actuation position 29 since the pressure in conduit 30 will not decrease below a predetermined level to allow the hydraulic piston of sensor SO to return to its normally closed position until the load on the motor 14 which caused the increased pressure on the conduit line 30 is released.
It will be appreciated that numerous modifications may be made without departing from the scope of this invention. For example, the llS5~19 hydraulic sensors 44 and 50, high speed and low speed pilot hydraulic conduit lines 45 and 54 and pressure switches 46 and 52 respectively could be replaced by a microprocessor and pressure transducer(s) if desired. Additionally, the motor employed in this invention could be of any power-driven type which utilized fluid controls to change from one speed ratio to another. Although hydraulic fluid controls are disclosed in the preferred embodiment, pneumatic or other types of fluid controls could also be used. Moreover, although the preferred embodiment contem-plated for the present invention is used on the motor of a winch con-nected with a crane, the instant invention is not limited to the present application but could be used whenever it is desirable to monitor and control the fluid pressure of the fluid controls of a motor.
From the foregoing it is believed that those familiar with the art will readily recognize and appreciate the novel concepts and features of the present invention. Obviously, while the invention has been des-cribed in relation to only a preferred embodiment, numerous variations, changes, and substitutions of equivalents will present themselves to persons skilled in the art and may be made without necessarily departing from the scope of the principles of this invention. As a result, the embodiment described herein is subject to various modlfications, changes, and the like wlth the scope of thls lnventlon belng determlned solely by reference to the claims appended hereto.
Claims (11)
1. In a motor of the type having a plurality of progressively higher fluid actuated speed ratios including a lowest speed ratio and a highest speed ratio, a fluid port in said motor corresponding to each of said speed ratios, a port conduit extending from each of said respective ports, a valve operably connected with each of said conduits, the improvement comprising selectively actuated electrical means operatively associated with said valve for positioning said valve to supply fluid under pressure to a selected one of said port conduits so that said motor is placed in said speed ratio corresponding to said port receiving said fluid from said one port conduit, a pressure sensor operatively associated with said one port conduit for sending a first impulse to actuate said means for positioning said valve to supply pressurized fluid to a respective port conduit extending from a respective port corresponding to a lower speed ratio when said sensor detects that said fluid pressure in said one conduit is above a first predetermined level.
2. The motor of the type as claimed in Claim 1 wherein said electrical means includes an electrical circuit and a solenoid con-nected with said circuit so that when said circuit is energized said solenoid operates to position said valve to supply fluid under pressure to said one port conduit and wherein said valve is spring-biased to supply said fluid under pressure to said respective port conduit ex-tending from said respective port corresponding to a lower speed ratio, said impulse from said pressure sensor de-energizing said circuit and thus said solenoid so that said valve under said spring bias is posi-tioned to supply pressurized fluid to said respective port conduit extending from said respective port corresponding to a lower speed ratio.
3. The motor as claimed in Claim 2 further comprising a second pressure sensor operatively associated with a selected port conduit for sending a second impulse when said valve is positioned to supply fluid to said selected port conduit to prevent said electrical means from positioning said valve to supply pressurized fluid to a respective port conduit extending from a respective port corresponding to a higher speed ratio when said fluid pressure in said selected port conduit is above a second predetermined level.
4. The motor as claimed in Claim 1 further comprising a second pressure sensor operatively associated with at least a selected port conduit for sending a second impulse when said valve is positioned to supply fluid to said selected port conduit to prevent said electrical means from positioning said valve to supply pressurized fluid to a respective port conduit extending from a respective port corresponding to a higher speed ratio when said fluid pressure in said selected port conduit is above a second predetermined level.
5. In a motor of the type having a plurality of progressively higher fluid actuated speed ratios including a lowest speed ratio and a highest speed ratio, a fluid port in said motor corresponding to each of said speed ratios, a port conduit extending from each of said respective ports, a valve operably connected with each of said conduits, the improvement comprising selectively actuated electrical means operatively associated with said valve for positioning said valve to supply fluid under pressure to a selected one of said port conduits so that said motor is placed in said speed ratio corresponding to said port receiving said fluid from said one port conduit, a first pressure sensor opera-tively associated with said one conduit for sending a first impulse to prevent said electrical means from positioning said valve to supply pressurized fluid to a respective port conduit extending from a respec-tive port corresponding to a higher speed ratio when said fluid pressure in said one port conduit is above a first predetermined level.
6. The motor of the type as claimed in Claim 5 wherein said electrical means includes an electrical circuit and a solenoid connected with said circuit so that when said circuit is energized said solenoid operates to position said valve to supply fluid under pressure to said respective port conduit extending from a respective port corresponding to a higher speed ratio, said first impulse from said first pressure sensor de-energizing said circuit and thus said solenoid so that said spring biased valve is prevented from being positioned to supply pres-surized fluid to said respective port conduit extending from said respective port corresponding to a higher speed ratio when said fluid pressure in said one port conduit is above said first predetermined level.
7. The motor as claimed in Claim 6 further comprising a second pressure sensor operatively associated with a selected port conduit for sending a second impulse to actuate said electrical means for position-ing said valve to supply pressurized fluid to a respective port conduit extended from a respective port corresponding to a lower speed ratio than said selected port conduit when said second sensor detects that said fluid pressure in said selected conduit is above a second pre-determined level.
8. The motor as claimed in Claim 1 or 5 wherein only two port conduits, ports and speed ratios respectively are included corresponding to said lowest speed ratio and said highest speed ratio, respectively.
9. A motor comprising:
a fluid actuated low speed ratio;
a fluid actuated high speed ratio;
a fluid port in said motor corresponding to each of said speed ratios;
a port conduit extending from each of said respective ports;
a valve operably connected with each of said conduits;
selectively actuated electrical means operatively associated with said valve for positioning said valve to supply fluid under pressure to a selected one of said port conduits so that said motor is placed in said speed ratio corresponding to said port receiving said fluid from said one port conduit;
a first pressure sensor operatively associated with said high speed port conduit for sending a first impulse to actuate said electrical means to position said valve to supply pressurized fluid to said low speed port conduit when said first sensor detects that said fluid pressure in said high speed conduit is above a first predetermined level.
a fluid actuated low speed ratio;
a fluid actuated high speed ratio;
a fluid port in said motor corresponding to each of said speed ratios;
a port conduit extending from each of said respective ports;
a valve operably connected with each of said conduits;
selectively actuated electrical means operatively associated with said valve for positioning said valve to supply fluid under pressure to a selected one of said port conduits so that said motor is placed in said speed ratio corresponding to said port receiving said fluid from said one port conduit;
a first pressure sensor operatively associated with said high speed port conduit for sending a first impulse to actuate said electrical means to position said valve to supply pressurized fluid to said low speed port conduit when said first sensor detects that said fluid pressure in said high speed conduit is above a first predetermined level.
10. A motor as claimed in Claim 9 further comprising a second pressure sensor operatively associated with said low speed port conduit for sending a second impulse to prevent said electrical means from positioning said valve to supply pressurized fluid to said high speed port conduit when said fluid pressure in said low speed port conduit is above a second predetermined level.
11. The motor as claimed in Claim 10 wherein said electrical means includes an electrical circuit and a solenoid connected with said circuit so that when said circuit is energized said solenoid operates to position said valve to supply fluid under pressure to said high speed port conduit and wherein said valve is spring-biased to supply fluid under pressure to said low speed port conduit, and when said valve is positioned to supply fluid to said high speed port conduit and said fluid pressure is above said first predetermined level said first impulse from said first pressure sensor de-energizes said circuit and thus said solenoid so that said valve under said spring bias is posi-tioned to supply pressurized fluid to said low speed port conduit, and when said valve is positioned to supply pressurized fluid to said low speed port conduit and said fluid pressure in said low speed port conduit is above said second predetermined level said second impulse from said second pressure sensor prevents said electrical means from positioning said valve to supply pressurized fluid to said high speed port conduit by preventing said circuit from being energized.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US10199579A | 1979-12-07 | 1979-12-07 | |
| US101,995 | 1979-12-07 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1155199A true CA1155199A (en) | 1983-10-11 |
Family
ID=22287567
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000363600A Expired CA1155199A (en) | 1979-12-07 | 1980-10-30 | Winch safety control |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1155199A (en) |
-
1980
- 1980-10-30 CA CA000363600A patent/CA1155199A/en not_active Expired
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |