EP0019352A2 - Draw works control system - Google Patents
Draw works control system Download PDFInfo
- Publication number
- EP0019352A2 EP0019352A2 EP80301041A EP80301041A EP0019352A2 EP 0019352 A2 EP0019352 A2 EP 0019352A2 EP 80301041 A EP80301041 A EP 80301041A EP 80301041 A EP80301041 A EP 80301041A EP 0019352 A2 EP0019352 A2 EP 0019352A2
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- EP
- European Patent Office
- Prior art keywords
- brake
- piston
- fluid
- bore
- accumulator
- 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
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- 230000005540 biological transmission Effects 0.000 claims abstract description 30
- 239000012530 fluid Substances 0.000 claims description 104
- 230000035939 shock Effects 0.000 abstract description 4
- 238000004891 communication Methods 0.000 description 12
- 230000033001 locomotion Effects 0.000 description 9
- 230000007935 neutral effect Effects 0.000 description 7
- 238000010276 construction Methods 0.000 description 6
- 230000004323 axial length Effects 0.000 description 5
- 230000007423 decrease Effects 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 230000002093 peripheral effect Effects 0.000 description 2
- 230000001105 regulatory effect Effects 0.000 description 2
- 230000009471 action Effects 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 230000000712 assembly Effects 0.000 description 1
- 238000000429 assembly Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 230000000994 depressogenic effect Effects 0.000 description 1
- 230000001627 detrimental effect Effects 0.000 description 1
- 230000009977 dual effect Effects 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 230000002028 premature Effects 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 230000000750 progressive effect Effects 0.000 description 1
- 230000004044 response Effects 0.000 description 1
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B66—HOISTING; LIFTING; HAULING
- B66D—CAPSTANS; WINCHES; TACKLES, e.g. PULLEY BLOCKS; HOISTS
- B66D5/00—Braking or detent devices characterised by application to lifting or hoisting gear, e.g. for controlling the lowering of loads
- B66D5/02—Crane, lift hoist, or winch brakes operating on drums, barrels, or ropes
- B66D5/24—Operating devices
- B66D5/26—Operating devices pneumatic or hydraulic
Definitions
- This invention relates to control systems for hydraulically operated draw works having winches, or the like, and which may have hydromechanical boom or hook type draw works transmission controls.
- Winches or as more generally known, draw works, are used in a large variety of operations and, as a consequence, there are draw works constructions available with widely varying degrees of sophisticated control and drive equipment.
- Some of the more sophisticated draw works constructions are hydraulically operated and include a hydraulic motor for driving a draw works drum.
- a hydraulically disengaged brake which brakes the drum to prevent unduly rapid lowering of a load to be hoisted.
- a multiple- speed, hydraulically controlled transmission may interconnect the drum and the drive motor therefor.
- the first is the so-called “drop and catch” lowering wherein the brake is fully disengaged and the load is allowed to fall at its maximum rate.
- the brake is once again engaged and further lowering is arrested.
- the second type of lowering is the so-called “controlled” lowering in which the brake is only partically disengaged thereby allowing a load to be lowered at some controlled rate less than the maximum.
- a control system for a hydraulically operated draw works or the like having a hydraulically disengaged brake; a transmission; a brake control valve, including a fluid inlet, and a fluid outlet, connected to the brake; and a source of fluid under pressure connected to the inlet includes means provided for causing modulated . application of the brake when the brake is applied after having been fully released, and for causing unmodulated application of the brake when the brake is applied after having been only partially released.
- the invention also includes an accumulator for use in a control system for a hydraulically operated draw works or the like having a hydraulically disengaged brake,a transmission, and a brake control valve, the accumulator including a body having a bore; an inlet in the body for connection to the control valve; an outlet in the body for connection to the brake; a hollow piston slidable within the bore; passageways extending from the hollow interior of the piston to the outer surface of the piston; springs biasing the piston to a predetermined position within the bore; a check valve located between the bore and the outlet to permit unrestricted fluid flow from the bore to the outlet and to prevent fluid flow from the outlet to the bore; and a metering orifice located in the piston and extending from the hollow interior of the piston to the outer surface of the piston to permit, in use, a continuous but limited rate of fluid flow between the outlet and the inlet.
- a control system for a hydraulically operated draw works or the like including a hydraulically disengaged brake, a multi-speed, hydraulically controlled transmission and a drum to be driven or braked.
- a multi-speed, hydraulically controlled transmission including ahigh speed section indicated schematically at 10 and a low speed section schematically indicated at 12.
- the transmission including the components 10 and 12 will be of the type that when fluid under pressure is directed to the high speed section 10, the output speed of the transmission will be in high gear, and when fluid under pressure is directed to the low speed section 12, the output speed of the transmission will be in the low range.
- the usual draw works assemblage will include a spring-engaged, hydraulically disengaged brake which may be of a conventional construction and which is illustrated schematically at 14.
- the system will also include a metering pump 16 which will be suitably coupled to the draw works drum-(not shown) through a one-way clutch (not shown) so as to be driven thereby when the load is lowered at a speed proportional to the rate of rotation of the draw works drum.
- the purpose of the metering pump 16 is to act as a governor and limit the rotational velocity of the drum.
- a hydraulic pump 20 typically driven by the prime mover of the vehicle.
- the pump 20 receives oil from a reservoir 22 and directs the same, under pressure, to a junction 24.
- One side of the junction 24 extends to a priority valve 26 which, in turn, permits the flow of fluid to the vehicle components 18.
- the other side of the junction 24 extends to the control system of the present invention.
- the priority valve 26 is of conventional construction and is operative to ensure delivery of fluid to the control system of the present invention at a pressure equal to or exceeding a predetermined minimum pressure. Frequently, hydraulic fluid flow requirements of the vehicle components 18 will cause the pressure to drop to a relatively low value which is insufficient to maintaim engagement of the components of the transmission. The priority valve 26 prevents such from occurring.
- the control system includes a control valve, generally designated 28, which comprises two valves in a common housing.
- Manual actuators, generally designated 30, are provided for the valve 28 in, for example, an operator area.
- the manual actuators 30 include, for example, a handle 32 which may be grasped by the operator to perform a variety of functions to be described.
- a console within the operator area is provided with a slot 34 in which the handle 32 may be moved.
- a first mechanical link shown schematically at 36, is attached to the handle 32 and extends to the control valve 28 to convey thereto mechanical motion of the handle 32 directing the selection of a particular transmission output speed.
- a similar linkage shown schematically at 38, extends to a brake control section of the valve 28 to convey mechanical movement of the handle 32 to the valve 28 to direct the flow of hydraulic fluid under pressure to the brake 14 to control its degree of disengagement.
- a third linkage extends to amotor speed and direction control system (not shown) which is operative to control the speed of the hydraulic drive motor for the draw works as well as its directional output.
- the linkages 36, 38 and 40 may be conventional in nature and, for example, in the form of control cables or linkages. It is only necessary that the linkage 36 be responsive to movement of the handle 32 in the right-left direction, as viewed in Fig. 1, and nonresponsive to other directions of movement thereof.
- the linkages 38 and 40 are similar, but are responsive only to up-down movements of the handle 32, as viewed in Fig. 1, and nonresponsive to left-right movement.
- the slot 34 defines a shift pattern for the handle 32. It includes a horizontally elongate slot 42. When, as viewed in Fig. 1, the handle 32 is disposed in the left-hand end of the slot 42, the control valve 28 will direct the transmission to select its high speed output. When the handle 32 is in the right-hand extremity of the slot 42, it will direct the control valve 28 to select the low speed range of the transmission.
- each end of the slot 42 there are provided downwardly extending slots 44 and 46.
- the linkage 40 will direct the motor speed and direction control system to drive the drum of the draw works to elevate the load.
- the degree of depression of the handle 32 in either of the slots 44 or 46 will control the speed of the drive motor for the winch.
- an upwardly extending slot 48 intermediate the ends of the slot 42.
- a direction by the valve 28 to the transmission will cause the latter to assume a neutral condition.
- the brake 14 will be allowed to progressively disengage and increase in speed as the handle 32 moves further up the slot.
- the linkage 40 may be directed, after the backlash has been taken up to drive the drum motor in a direction to lower the load at a particular speed, but only if the load is not of sufficient magnitude for gravity to overcome .the friction of the draw works assemblage.
- a short, downwardly extending slot 50 intersects the slot 42 intermediate its ends.
- the transmission will be directed, by the valve 28, to remain in neutral.
- the use of the slot 50 enables the energization of the drive motor for the winch while the transmission is in neutral to enable warmup of the components without changing the position of the load carried by the draw works.
- This feature of the invention when used, ensures excellent response of the system in cold environments.
- hydraulic fluid under pressure is directed along a line 52 to the transmission control side of the valve 28 in a manner to be described in greater detail hereinafter. It is also directed to a check valve system 54.
- the check valve system 54 includes a first check valve 56 which precludes backflow from any downstream component to the junction 24. Just downstream of the check valve 56 there is located a junction 58. Connected to the junction 58 is a check valve 60 which extends to the metering pump 16. The check valve 60 precludes discharge of an accumulator 62 except through the valve 28.
- the valve 28 includes a housing 100 formed of a center housing 102, a right end housing 104 and a left end housing 106.
- the left end housing 106 receives, in a conventional fashion, cable ends 108 and 110 of the linkages 36 and 38, respectively.
- the center housing 100 includes a transmission control bore 112 and a brake control bore 114.
- the housing 104 includes cavities 116 which are aligned with the bores 112 and 114 and house bi-directional spring centering assemblies 118 which are operative to center respective ones of a transmission control spool 120 in the bore 112 and a brake control spool 122 in the bore 114 to the positions illustrated in Fig. 2 regardless of whether the spools 120 and 122 have been shifted to the right or to the left.
- The'spools 120 and 122 have leftward extensions which extend into the housing 106 for connection to the cable ends 108 and 110 whereby the spools 120 and 122 may be shifted to the right or to the left in their bores by manipulation of the handle 32, as mentioned previously.
- the transmission control bore 112 includes a first outlet port 124 which may be connected to the high section 10 of the transmission to be con- _ trolled and a second outlet port 126 which may be connected to the low section 12 of the transmission. Intermediate the outlet ports 124 and 126 is an inlet port 128 which is connected to the junction 24 (Fig. 1). On the sides of the outlet ports 124 and 126 opposite from the inlet port 128, the bore 112 is provided with drain ports 130 and 132, respectively, which drain ports are also common to the brake control bore 114 and which are connected to the reservoir 22.
- the spool 120 includes spaced lands 134 and 136.
- the land 134 will either preclude fluid communication between the ports 124 and 128 or the ports 126 and 128.
- the land 136 will either preclude fluid communication between the ports 126 and 128 or the ports 126 and 132.
- the lands 134 and 136 block the flow of pressurized fluid into either of the transmission sections 10 and 12, while at the same time allow fluid flow from those sections to the reservoir 22 through the drain ports 130 and 132 respectively.
- the handle 32 To command the transmission to operate in its low range, the handle 32 is moved to the right in the slot 42, as mentioned previously. This will cause a commensurate shift of the spool 120 to the right within the bore 112. This, in turn, will establish fluid communication between the inlet 128 and the outlet 126. Flow to drain through the port 132 is blocked by the right-hand side of the land 136 in such a case, while flow to drain through the port 130 continues because the land 140 does not move far enough to block communication between the outlet port 124 and the drain port 130. Flow from the inlet 128 to the outlet 124 continues to be blocked but now by land 222 instead of land 134.
- the spool 120 will shift to the left within the bore 112 from the position shown.
- the land 222 will shift to the left to preclude fluid communication between the port 124 and the drain port while the land 134 enables fluid flow from the inlet port 128 to the port 124.
- the rather long axial length of the land 136 will continue to block the flow of fluid to the outlet port 126.
- the brake control bore 114 includes a cavity 150 which is connected to junction 58 for receipt of fluid under pressure.
- an outlet port 152 which is adapted to be connected to both a brake accumulator 174 and to the metering pump 16, as shown in Fig. 4.
- the outlet port 152 is disposed between the cavity 150 and the outlet port 132 which extends to the reservoir 22.
- the spool 122 includes a land 158 having a relatively long axial length which is normally operative to preclude the flow of fluid from the cavity 150 to the outlet port 152 while allowing flow of fluid from the outlet port 152 to drain through the drain port 132 or to interrupt fluid communication between the drain port 132 and the outlet port 152 and allow fluid to flow from the cavity 150 to the outlet port 152 under circumstances to be described in greater detail hereinafter.
- the land 158 includes oppositely disposed, axially extending grooves 160, 162 and 164 in its periphery.
- Each of the grooves 160, 162 and 164 opens to the inlet side of the land 158 and, as can be best seen in Fig. 2, the groove 160 has a relatively long axial length, the groove 162 has an intermediate axial length, while the groove 164 has a relatively short axial length.
- the grooves 162 and 164 have relatively large cross sections.
- the groove 160 has a relatively small cross section.
- all three grooves have a progressively decreasing cross section from left to right.(Fig.2)
- the grooves 160, 162 and 164 serve as metering grooves to assist in attaining such a degree of brake disengagement control. Specifically, the further the spool 122 is moved to the right, as viewed in Fig. 2, the greater the fluid flow from the cavity 150 to the outlet 152 through the groove 160. The greater the fluid flow, the greater the degree of disengagement of the brake 14 which, it will be recalled, is of the hydraulically disengaged type.
- a spring 166 has been included to provide positive feedback to the-operator. As the leading edge of the groove 164 approaches the leftmost surface of cavity 168 which leads to port 152, the washer 167 contacts a shoulder 170 of the bore 114. Any further rightward movement of spool 122 compresses the spring 166 and provides for a positive operator feel when the maximum speed groove 164 has been entered;
- fluid flowing from the port 152 will flow to a junction 172 and simultaneously to the metering pump 16 and a brake accumulator, generally shown at 174.
- the brake is of the spring engaged-hydraulically disengaged type and therefore the brake 14 may be disengaged, and the load lowered, only by supplying brake 14 with hydraulic fluid from the port 152.
- the greater the fluid pressure the greater the degree of disengagement and the greater the quantity of fluid required to cause progressive disengagement.
- the brake 14 can only be supplied with hydraulic fluid through the brake accumulator 174.
- Hydraulic fluid metered through the grooves 160, 162 and 164 is supplied to a brake accumulator port 176 in a housing 178 of the accumulator 174.
- a bore 180 which contains a piston 182.
- the piston 182 has a relatively thin wall 184 which is perforated by a number of passageways 186. As viewed in Fig. 4, the piston is urged to the left by springs 188 and 190.
- the spring pocket 192 is ultimately connected to the brake 14 by a passageway 194, a check valve 196, an accumulator chamber 198 and an accumulator port 200.
- a brake release piston 202 Located within the brake 14 is a brake release piston 202, a brake return spring 204 and a brake cylinder 206.
- the brake 14 is otherwise conventional in construction and need not be further explained. It is sufficient to note that when the piston 202 is in the leftmost position, as viewed in Fig. 4, the brake 14 will be fully applied and as the piston 202 is forced an increasing distance to the right by pressurized fluid in the cylinder 206, the brake 14 will be-increasingly released.
- the piston return spring 204 creates a force opposing fluid pressure in the cylinder 206. Therefore, if fluid pressure in chamber 206 is insufficient to overcome the force created by the spring 204, the piston 202 will be urged to the left and the brake 14 will be applied.
- the pressure of the hydraulic fluid supplied from the outlet port 152 to the accumulator port.176, and consequently the brake 14, may be varied by operator actuation of the brake spool 122.
- brake release will be accomplished by one of two methods. If fluid supply pressure is high, the force on the piston 202 will be sufficient to completely overcome the force created by-the spring 204. In this case, the brake piston 202 will be forced fully to the right and the brake 14 will be completely released. As a consequence of this large piston 202 movement, a large volume of hydraulic fluid will enter the brake cylinder 206.
- a relatively low hydraulic fluid pressure will be insufficient to completely overcome the force created by the return spring 204 and the brake piston 202 will be forced only a short distance to the right. This piston movement will be insufficient to completely release the brake 14 but will cause slippage. In this situation, the volume of fluid entering the piston cylinder 206 will be relatively small.
- piston surfaces 208 and 210 Located on the piston 182 are piston surfaces 208 and 210 upon which the fluid located in the accumulator chamber 198 will act.
- piston surfaces 208 and 210 Located within a piston wall 212 is a metering orifice 214 which establishes fluid communication between the accumulator chamber 198 and the accumulator port 176 through the piston passageways 186.
- the accumulator chamber 198 will no longer be in direct fluid communication with the port 176 and any remaining fluid in the accumulator chamber 198 and the brake cylinder 206 must flow through the metering orifice 214 and the piston passageways 186.
- the metering orifice 214 will limit the flow of fluid from the piston cylinder 206 and thus cause gradual application of the brake 14.
- the fluid Upon reaching the accumulator port 176, the fluid flows through the piston passages 186, the spring pocket 192, the passageway 194, the check valve 196 and finally through the accumulator port 200 to the brake cylinder 206.
- the accumulator chamber 198 will become completely filled during this process.
- the brake spool 122 When it is desired to stop descent of the load, the brake spool 122 is shifted to the neutral position as shown in Fig. 2. As indicated above, the outlet port 152 will then be in fluid communication with the drain port 132, and consequently, the tank 22. The accumulator spring pocket 192 and the passageway 194 will thus be drained by the drain port 132. Fluid pressure in the accumulator chamber 198 and the piston cylinder 206 will then cause the check valve 196 to be completely seated.
- the piston surface 208 will clear the edge 216 of the port 176 and the piston 182 will act as a relief valve.
- the springs 188 and 190 will force the piston 182 to once again move towards the left, closing off accumulator port 176.
- any further fluid flow from the accumulator chamber 198 and the brake cylinder 206 must be through the metering orifice 214.
- the limited flow through the metering orifice 214 will cause the gradual relief of fluid pressure in the brake cylinder 206 and thus provide modulated brake application and gradual arrest of the load.
- fluid flow from the cavity 150 to the outlet 152 will be through less than all of the grooves 160, 162 and 164. This will generate a fluid pressure in the brake cylinder 206 which will be less than that required to completely release the brake 14. However, fluid pressure in the cylinder 206 will be of a magnitude that will cause slippage and limited rotation of the brake 14. Since the brake piston 202 will move only a slight distance to the right, a relatively small volume of fluid will be contained in the brake cylinder 206.
- the system also includes means whereby the accumulator 62 may be discharged when the pump 20 or engine is inoperative.
- the fluid from the accumulator 62 is discharged through orifice 224 to either drain 130 to sump 22, or port 128 back through pump 20 tc sump 22, depending upon the position of spools 122 and 140.
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Fluid-Pressure Circuits (AREA)
- Braking Arrangements (AREA)
- Regulating Braking Force (AREA)
Abstract
Description
- This invention relates to control systems for hydraulically operated draw works having winches, or the like, and which may have hydromechanical boom or hook type draw works transmission controls.
- Prior art of possible relevance includes our U.S. Patent Specification No. 4,048,799.
- Winches, or as more generally known, draw works, are used in a large variety of operations and, as a consequence, there are draw works constructions available with widely varying degrees of sophisticated control and drive equipment. Some of the more sophisticated draw works constructions are hydraulically operated and include a hydraulic motor for driving a draw works drum. Typically, there is provided a hydraulically disengaged brake which brakes the drum to prevent unduly rapid lowering of a load to be hoisted. A multiple- speed, hydraulically controlled transmission may interconnect the drum and the drive motor therefor.
- There is also provided means for regulating the amount of control fluid applied to the hydraulically disengaged brake to control the degree of disengagement of such brake and thereby control the rate of decent of an elevated load.
- In the usual case, two types of load-lowering are desirable. The first is the so-called "drop and catch" lowering wherein the brake is fully disengaged and the load is allowed to fall at its maximum rate. When the load has been lowered the desired amount, the brake is once again engaged and further lowering is arrested. The second type of lowering is the so-called "controlled" lowering in which the brake is only partically disengaged thereby allowing a load to be lowered at some controlled rate less than the maximum.
- During the drop and catch lowering, initial engagement of the brake to catch the load will cause "grabbing" of the brake rather than smooth engagement. This, in turn, communicates a considerable shock to the internal components of the brake and draw works components connected to the output of the brake. This shock reduces the useful life of such components by causing premature wear and failure thereof.
- It is therefore highly desirable therefore to prevent such shock-loading by providing for gradual application of the brake in drop and-catch lowering.
- During controlled lowering, however, such a feature is not desirable since modulation of brake application will result in additional travel of the load after the operator applies the brake thereby making fine control of load position difficult. Moreover, such modulation is not necessary since changes in torque levels are not so drastic as to cause the detrimental shock noted above.
- According to the present invention, a control system for a hydraulically operated draw works or the like having a hydraulically disengaged brake; a transmission; a brake control valve, including a fluid inlet, and a fluid outlet, connected to the brake; and a source of fluid under pressure connected to the inlet includes means provided for causing modulated . application of the brake when the brake is applied after having been fully released, and for causing unmodulated application of the brake when the brake is applied after having been only partially released.
- The invention also includes an accumulator for use in a control system for a hydraulically operated draw works or the like having a hydraulically disengaged brake,a transmission, and a brake control valve, the accumulator including a body having a bore; an inlet in the body for connection to the control valve; an outlet in the body for connection to the brake; a hollow piston slidable within the bore; passageways extending from the hollow interior of the piston to the outer surface of the piston; springs biasing the piston to a predetermined position within the bore; a check valve located between the bore and the outlet to permit unrestricted fluid flow from the bore to the outlet and to prevent fluid flow from the outlet to the bore; and a metering orifice located in the piston and extending from the hollow interior of the piston to the outer surface of the piston to permit, in use, a continuous but limited rate of fluid flow between the outlet and the inlet.
- One example of a control system according to the invention will now be described with reference'to the accompanying drawings in which:-
- Figure 1 is a schematic view of the hydraulic control system illustrating mechanical details of manual actuators therefor;
- Figure 2 is a sectional view of a control valve - of the system, which also schematically illustrates peripheral components utilized in the system;
- Figure 3 is a sectional view taken approximately along the line III-III of Figure 2; and,
- Figure 4 is a sectional view of the accumulator constructed according to the present invention, which also schematically illustrates peripheral components.
- One example of a control system for a hydraulically operated draw works or the like including a hydraulically disengaged brake, a multi-speed, hydraulically controlled transmission and a drum to be driven or braked.is illustrated in the drawings and, with reference to Figure 1, is seen to include a multi-speed, hydraulically controlled transmission including ahigh speed section indicated schematically at 10 and a low speed section schematically indicated at 12. As will be seen, the transmission including the
components high speed section 10, the output speed of the transmission will be in high gear, and when fluid under pressure is directed to thelow speed section 12, the output speed of the transmission will be in the low range. - The usual draw works assemblage will include a spring-engaged, hydraulically disengaged brake which may be of a conventional construction and which is illustrated schematically at 14. The system will also include a
metering pump 16 which will be suitably coupled to the draw works drum-(not shown) through a one-way clutch (not shown) so as to be driven thereby when the load is lowered at a speed proportional to the rate of rotation of the draw works drum. The purpose of themetering pump 16 is to act as a governor and limit the rotational velocity of the drum. - When the draw works system is used in a vehicle as, for example, a pipe layer, there will be a number of additional hydraulically controlled components associated with the vehicle, which 'components are schematically illustrated at 18 and may include steering clutches, power transmission and vehicle brake elements. Fluid under pressure is provided to the system by a hydraulic pump 20, typically driven by the prime mover of the vehicle. The pump 20 receives oil from a
reservoir 22 and directs the same, under pressure, to ajunction 24. One side of thejunction 24 extends to apriority valve 26 which, in turn, permits the flow of fluid to thevehicle components 18. The other side of thejunction 24 extends to the control system of the present invention. - The
priority valve 26 is of conventional construction and is operative to ensure delivery of fluid to the control system of the present invention at a pressure equal to or exceeding a predetermined minimum pressure. Frequently, hydraulic fluid flow requirements of thevehicle components 18 will cause the pressure to drop to a relatively low value which is insufficient to maintaim engagement of the components of the transmission. Thepriority valve 26 prevents such from occurring. - The control system includes a control valve, generally designated 28, which comprises two valves in a common housing. Manual actuators, generally designated 30, are provided for the
valve 28 in, for example, an operator area. Themanual actuators 30 include, for example, ahandle 32 which may be grasped by the operator to perform a variety of functions to be described. A console within the operator area is provided with aslot 34 in which thehandle 32 may be moved. - A first mechanical link, shown schematically at 36, is attached to the
handle 32 and extends to thecontrol valve 28 to convey thereto mechanical motion of thehandle 32 directing the selection of a particular transmission output speed. A similar linkage, shown schematically at 38, extends to a brake control section of thevalve 28 to convey mechanical movement of thehandle 32 to thevalve 28 to direct the flow of hydraulic fluid under pressure to thebrake 14 to control its degree of disengagement. - A third linkage, shown schematically at 40, extends to amotor speed and direction control system (not shown) which is operative to control the speed of the hydraulic drive motor for the draw works as well as its directional output.
- The
linkages linkage 36 be responsive to movement of thehandle 32 in the right-left direction, as viewed in Fig. 1, and nonresponsive to other directions of movement thereof. Thelinkages handle 32, as viewed in Fig. 1, and nonresponsive to left-right movement. - The
slot 34 defines a shift pattern for thehandle 32. It includes a horizontally elongate slot 42. When, as viewed in Fig. 1, thehandle 32 is disposed in the left-hand end of the slot 42, thecontrol valve 28 will direct the transmission to select its high speed output. When thehandle 32 is in the right-hand extremity of the slot 42, it will direct thecontrol valve 28 to select the low speed range of the transmission. - At each end of the slot 42, there are provided downwardly extending
slots handle 32 is aligned with either of theslots linkage 40 will direct the motor speed and direction control system to drive the drum of the draw works to elevate the load. The degree of depression of thehandle 32 in either of theslots - Also included is an upwardly extending
slot 48 intermediate the ends of the slot 42. When thehandle 32 is aligned with theslot 48, a direction by thevalve 28 to the transmission will cause the latter to assume a neutral condition. As thehandle 32 is elevated in theslot 48, thebrake 14 will be allowed to progressively disengage and increase in speed as thehandle 32 moves further up the slot. At the same time thelinkage 40 may be directed, after the backlash has been taken up to drive the drum motor in a direction to lower the load at a particular speed, but only if the load is not of sufficient magnitude for gravity to overcome .the friction of the draw works assemblage. - A short, downwardly extending
slot 50 intersects the slot 42 intermediate its ends. When thehandle 32 is directed downwardly into theslot 50, there will be a direction to the motor speed and direction control system to energize the drive motor for the draw works. - Whenever the
handle 32 is aligned with either of theslots valve 28, to remain in neutral. Thus, the use of theslot 50 enables the energization of the drive motor for the winch while the transmission is in neutral to enable warmup of the components without changing the position of the load carried by the draw works. This feature of the invention, when used, ensures excellent response of the system in cold environments. - Returning to the
junction 24, hydraulic fluid under pressure is directed along aline 52 to the transmission control side of thevalve 28 in a manner to be described in greater detail hereinafter. It is also directed to acheck valve system 54. Thecheck valve system 54 includes afirst check valve 56 which precludes backflow from any downstream component to thejunction 24. Just downstream of thecheck valve 56 there is located ajunction 58. Connected to thejunction 58 is acheck valve 60 which extends to themetering pump 16. Thecheck valve 60 precludes discharge of anaccumulator 62 except through thevalve 28. - Turning now to Figs. 2 and 3, the construction of the
control valve 28 will be described in greater detail. Thevalve 28 includes ahousing 100 formed of acenter housing 102, aright end housing 104 and aleft end housing 106. Theleft end housing 106 receives, in a conventional fashion, cable ends 108 and 110 of thelinkages center housing 100 includes a transmission control bore 112 and a brake control bore 114. Thehousing 104 includescavities 116 which are aligned with thebores spring centering assemblies 118 which are operative to center respective ones of a transmission control spool 120 in thebore 112 and abrake control spool 122 in thebore 114 to the positions illustrated in Fig. 2 regardless of whether thespools 120 and 122 have been shifted to the right or to the left. -
The'spools 120 and 122 have leftward extensions which extend into thehousing 106 for connection to the cable ends 108 and 110 whereby thespools 120 and 122 may be shifted to the right or to the left in their bores by manipulation of thehandle 32, as mentioned previously. - The transmission control bore 112 includes a
first outlet port 124 which may be connected to thehigh section 10 of the transmission to be con- _ trolled and asecond outlet port 126 which may be connected to thelow section 12 of the transmission. Intermediate theoutlet ports inlet port 128 which is connected to the junction 24 (Fig. 1). On the sides of theoutlet ports inlet port 128, thebore 112 is provided withdrain ports reservoir 22. - The spool 120 includes spaced
lands 134 and 136. Dependent upon the position of the spool 120 within thebore 112, theland 134 will either preclude fluid communication between theports ports ports ports lands 134 and 136 block the flow of pressurized fluid into either of thetransmission sections reservoir 22 through thedrain ports - To command the transmission to operate in its low range, the
handle 32 is moved to the right in the slot 42, as mentioned previously. This will cause a commensurate shift of the spool 120 to the right within thebore 112. This, in turn, will establish fluid communication between theinlet 128 and theoutlet 126. Flow to drain through theport 132 is blocked by the right-hand side of the land 136 in such a case, while flow to drain through theport 130 continues because theland 140 does not move far enough to block communication between theoutlet port 124 and thedrain port 130. Flow from theinlet 128 to theoutlet 124 continues to be blocked but now byland 222 instead ofland 134. - Conversely, when the
handle 32 is shifted to the left, as viewed in Fig. 1, to direct the transmission to operate in its high range, the spool 120 will shift to the left within thebore 112 from the position shown. At this time, theland 222 will shift to the left to preclude fluid communication between theport 124 and the drain port while theland 134 enables fluid flow from theinlet port 128 to theport 124. The rather long axial length of the land 136 will continue to block the flow of fluid to theoutlet port 126. - Turning now to the brake control section of the
valve 28, the brake control bore 114 includes acavity 150 which is connected tojunction 58 for receipt of fluid under pressure. Just to the right of thecavity 150 as seen in Fig. 2, is anoutlet port 152 which is adapted to be connected to both abrake accumulator 174 and to themetering pump 16, as shown in Fig. 4. Theoutlet port 152 is disposed between thecavity 150 and theoutlet port 132 which extends to thereservoir 22. - The
spool 122 includes aland 158 having a relatively long axial length which is normally operative to preclude the flow of fluid from thecavity 150 to theoutlet port 152 while allowing flow of fluid from theoutlet port 152 to drain through thedrain port 132 or to interrupt fluid communication between thedrain port 132 and theoutlet port 152 and allow fluid to flow from thecavity 150 to theoutlet port 152 under circumstances to be described in greater detail hereinafter. - As seen in Figs. 2 and 3, the
land 158 includes oppositely disposed, axially extendinggrooves grooves land 158 and, as can be best seen in Fig. 2, thegroove 160 has a relatively long axial length, thegroove 162 has an intermediate axial length, while thegroove 164 has a relatively short axial length. As seen in Fig. 3, thegrooves groove 160 has a relatively small cross section. Moreover, all three grooves have a progressively decreasing cross section from left to right.(Fig.2) - In the case of a brake in a draw works, it is desired that there be an infinite number of degrees of disengagement so that the speed of descent of the load can be regulated. The
grooves spool 122 is moved to the right, as viewed in Fig. 2, the greater the fluid flow from thecavity 150 to theoutlet 152 through thegroove 160. The greater the fluid flow, the greater the degree of disengagement of thebrake 14 which, it will be recalled, is of the hydraulically disengaged type. For greater rightward shifts of thespool 122 within thebore 114, fluid communication between thecavity 150 and theport 152 will be established through thelarger groove 162 so that fluid flow will be less restricted. For even greater rightward shifts of thespool 122, fluid communication between thecavity 150 andport 152 will be established through all threegrooves - To enable the operator to feel when the condition of maximum lowering rate is being approached, a spring 166 has been included to provide positive feedback to the-operator. As the leading edge of the
groove 164 approaches the leftmost surface ofcavity 168 which leads toport 152, thewasher 167 contacts a shoulder 170 of thebore 114. Any further rightward movement ofspool 122 compresses the spring 166 and provides for a positive operator feel when themaximum speed groove 164 has been entered; - As best seen in Figs. 1 and 4, fluid flowing from the
port 152 will flow to ajunction 172 and simultaneously to themetering pump 16 and a brake accumulator, generally shown at 174. - As explained above, the brake is of the spring engaged-hydraulically disengaged type and therefore the
brake 14 may be disengaged, and the load lowered, only by supplyingbrake 14 with hydraulic fluid from theport 152. In such a brake, the greater the fluid pressure the greater the degree of disengagement and the greater the quantity of fluid required to cause progressive disengagement. As shown in Figs. 1 and 4, thebrake 14 can only be supplied with hydraulic fluid through thebrake accumulator 174. - Hydraulic fluid metered through the
grooves brake accumulator port 176 in ahousing 178 of theaccumulator 174. Located within thehousing 178 is a bore 180 which contains apiston 182. Thepiston 182 has a relativelythin wall 184 which is perforated by a number ofpassageways 186. As viewed in Fig. 4, the piston is urged to the left bysprings - When fluid is supplied to the
port 176, it will flow through thepiston passageways 186 and into aspring pocket 192. Thespring pocket 192 is ultimately connected to thebrake 14 by apassageway 194, acheck valve 196, anaccumulator chamber 198 and anaccumulator port 200. - Located within the
brake 14 is abrake release piston 202, abrake return spring 204 and a brake cylinder 206. Thebrake 14 is otherwise conventional in construction and need not be further explained. It is sufficient to note that when thepiston 202 is in the leftmost position, as viewed in Fig. 4, thebrake 14 will be fully applied and as thepiston 202 is forced an increasing distance to the right by pressurized fluid in the cylinder 206, thebrake 14 will be-increasingly released. - The
piston return spring 204 creates a force opposing fluid pressure in the cylinder 206. Therefore, if fluid pressure in chamber 206 is insufficient to overcome the force created by thespring 204, thepiston 202 will be urged to the left and thebrake 14 will be applied. - As stated above, the pressure of the hydraulic fluid supplied from the
outlet port 152 to the accumulator port.176, and consequently thebrake 14, may be varied by operator actuation of thebrake spool 122. Depending on the pressure of fluid supplied to thebrake 14, brake release will be accomplished by one of two methods. If fluid supply pressure is high, the force on thepiston 202 will be sufficient to completely overcome the force created by-thespring 204. In this case, thebrake piston 202 will be forced fully to the right and thebrake 14 will be completely released. As a consequence of thislarge piston 202 movement, a large volume of hydraulic fluid will enter the brake cylinder 206. - A relatively low hydraulic fluid pressure will be insufficient to completely overcome the force created by the
return spring 204 and thebrake piston 202 will be forced only a short distance to the right. This piston movement will be insufficient to completely release thebrake 14 but will cause slippage. In this situation, the volume of fluid entering the piston cylinder 206 will be relatively small. - As will be seen in Fig. 2, when the
brake spool 122 is returned to the neutral position, theoutlet port 152 will be connected to therelief port 132 and consequently to thetank 22. This will cause the pressure of the fluid supplied to theaccumulator port 176, and consequently thespring chamber 192, to drop to a very low level. The pressurized fluid remaining in theaccumulator chamber 198 and the brake cylinder 206 will then cause thecheck valve 196 to seat, precluding reverse fluid flow through thespring chamber 192. All fluid from thebrake 14 will thus be forced through the chamber 19.8 and towards the left end of thepiston 182. - Located on the
piston 182 arepiston surfaces accumulator chamber 198 will act. Located within apiston wall 212 is ametering orifice 214 which establishes fluid communication between theaccumulator chamber 198 and theaccumulator port 176 through thepiston passageways 186. - when the pressure of fluid supplied to the
brake 14 is relieved, reverse flow to thetank 22 through theports - If the pressure, and therefore the volume, of fluid located in the brake cylinder 206 is low, as is the situation during controlled lowering when the
brake 14 is only partially released, there will be insufficient fluid in theaccumulator chamber 198 and brake cylinder 206 to fully compress thesprings accumulator piston 182 will travel a slight distance to the right, this travel will not compress thesprings accumulator chamber -198 and brake cylinder 206 sufficient to cause slippage of thebrake 14. Any fluid located in theaccumulator chamber 198 and the brake cylinder 206 will simply flow through themetering orifice 214 as thepiston 182 slowly moves to the left and will be ultimately returned to thetank 22 through thecontrol valve 28. - If the pressure, and therefore the volume, of fluid supplied to and entering the
brake 14 is large, as when thebrake 14 is fully released, reverse flow to thecontrol valve 28 will be somewhat different. In this situation, fluid pressure in - theaccumulator chamber 198 and the brake cylinder 206 will be sufficient, when acting on the accumulator piston surfaces 208 and 210, to fully compress thesprings piston surface 208 moves beyond aport edge 216, theaccumulator piston 182 will act as a relief valve and allow a large volume of fluid to flow to theaccumulator port 176. As the residual pressure in thebrake 14 and the accumulator chamber 198 - decreases, thesprings piston 182 to the left. Thesprings piston 182 will cause a backpressure in theaccumulator chamber 198 and the brake cylinder 206 sufficient to maintain slippage in thebrake 14. - Once the
piston 182 has been urged a short distance to the left, theaccumulator chamber 198 will no longer be in direct fluid communication with theport 176 and any remaining fluid in theaccumulator chamber 198 and the brake cylinder 206 must flow through themetering orifice 214 and thepiston passageways 186. Themetering orifice 214 will limit the flow of fluid from the piston cylinder 206 and thus cause gradual application of thebrake 14. - In operation, there will be two distinct modes of load lowering available to the operator. The first is "drop and catch" lowering where it is desired to lower the load for a distance at the maximum rate available and then arrest lowering at a particular point. The second mode is "controlled" lowering where it is desired to lower a load at a speed somewhat less than the maximum available. As described above, when lowering at the maximum rate is desired, the
brake spool 122 will be in the rightmost position as viewed in Fig. 2. High pressure fluid will be allowed to flow through thegrooves cavity 150 to theoutlet port 152. As shown in Fig. 4, fluid flow from theoutlet port 152 will proceed to thejunction 172 and then to theaccumulator port 176 and themetering pump 16. Upon reaching theaccumulator port 176, the fluid flows through thepiston passages 186, thespring pocket 192, thepassageway 194, thecheck valve 196 and finally through theaccumulator port 200 to the brake cylinder 206. Theaccumulator chamber 198 will become completely filled during this process. - Since fluid pressure and flow is at its maximum, the
brake piston 202 will be forced completely to the right and thebrake 14 will be fully released. The load will therefore drop at its maximum rate. - When it is desired to stop descent of the load, the
brake spool 122 is shifted to the neutral position as shown in Fig. 2. As indicated above, theoutlet port 152 will then be in fluid communication with thedrain port 132, and consequently, thetank 22. Theaccumulator spring pocket 192 and thepassageway 194 will thus be drained by thedrain port 132. Fluid pressure in theaccumulator chamber 198 and the piston cylinder 206 will then cause thecheck valve 196 to be completely seated. - Since the
check valve 196 is closed, all hydraulic fluid to be discharged from thebrake 14 must move theaccumulator piston 182 against thesprings accumulator chamber 198 and the piston cylinder 206 is high, the fluid acting upon the piston surfaces 208 and 210 will create a force sufficient to fully compress thesprings - As the
piston 182 moves to the right, thepiston surface 208 will clear theedge 216 of theport 176 and thepiston 182 will act as a relief valve. As the pressure of fluid in theaccumulator chamber 198 and the piston cylinder 206 decreases, thesprings piston 182 to once again move towards the left, closing offaccumulator port 176. - Since the
springs piston 182 to act upon fluid contained in theaccumulator chamber 198 with a force sufficient to cause a fluid backpressure in theaccumulator chamber 198 and the piston cylinder 206 such that thebrake 14 will continue to slip. - With the
accumulator chamber 198 no longer in direct fluid communication withaccumulator port 176, any further fluid flow from theaccumulator chamber 198 and the brake cylinder 206 must be through themetering orifice 214. The limited flow through themetering orifice 214 will cause the gradual relief of fluid pressure in the brake cylinder 206 and thus provide modulated brake application and gradual arrest of the load. - During controlled lowering, fluid flow from the
cavity 150 to theoutlet 152 will be through less than all of thegrooves brake 14. However, fluid pressure in the cylinder 206 will be of a magnitude that will cause slippage and limited rotation of thebrake 14. Since thebrake piston 202 will move only a slight distance to the right, a relatively small volume of fluid will be contained in the brake cylinder 206. - When the
brake valve 122 is returned to the neutral position, fluid flow from theaccumulator chamber 198 and the piston cylinder 206 will once again be limited to the left end of thepiston 182 by action of thecheck valve 196. - Since during controlled lowering the pressure and volume of fluid contained in brake cylinder 206 is low, the volume of fluid acting on the piston surfaces 208 and 210 will not fully compress
springs springs brake 14. Brake application will be immediate. - It will thus be seen that the addition of the
accumulator 174 to a draw works control system will provide the dual advantages of modulated braking during high-speed lowering and unmodulated rapid brake application during controlled lowering. - The system also includes means whereby the
accumulator 62 may be discharged when the pump 20 or engine is inoperative. The fluid from theaccumulator 62 is discharged through orifice 224 to either drain 130 tosump 22, orport 128 back through pump 20tc sump 22, depending upon the position ofspools
Claims (6)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
PCT/US1979/000293 WO1980002446A1 (en) | 1979-05-02 | 1979-05-02 | Draw works transmission control |
WOPCT/US79/00293 | 1979-05-02 |
Publications (3)
Publication Number | Publication Date |
---|---|
EP0019352A2 true EP0019352A2 (en) | 1980-11-26 |
EP0019352A3 EP0019352A3 (en) | 1981-02-18 |
EP0019352B1 EP0019352B1 (en) | 1984-07-11 |
Family
ID=22147578
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP19800301041 Expired EP0019352B1 (en) | 1979-05-02 | 1980-04-02 | Draw works control system |
Country Status (5)
Country | Link |
---|---|
EP (1) | EP0019352B1 (en) |
JP (1) | JPH025680B2 (en) |
DE (1) | DE3068492D1 (en) |
SU (1) | SU1074400A3 (en) |
WO (1) | WO1980002446A1 (en) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1983000849A1 (en) * | 1981-09-11 | 1983-03-17 | Golan, Kenneth, F. | Control system with selective pressure staging |
Citations (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR657612A (en) * | 1927-07-18 | 1929-05-24 | Vickers Electrical Co Ltd | Improvements to the braking devices of mobile devices or devices, in particular the mechanisms of winding, traction, extraction winches, etc. |
US2355749A (en) * | 1943-05-31 | 1944-08-15 | Polson Alexander David | Brake for hoist machinery |
DE1011132B (en) * | 1954-11-12 | 1957-06-27 | Siemens Ag | United driving and safety brake for conveyor machines |
US2912286A (en) * | 1957-03-29 | 1959-11-10 | New York Air Brake Co | Fluid pressure power brake system |
US3170543A (en) * | 1962-12-06 | 1965-02-23 | Goodyear Tire & Rubber | Delay valve |
DE1431991A1 (en) * | 1966-09-01 | 1969-07-10 | Gutehoffnungshuette Sterkrade | Operating device for the hydraulic braking device of a mining shaft hoisting machine or the like. |
US3463278A (en) * | 1967-11-02 | 1969-08-26 | Caterpillar Tractor Co | Transmission and brake for cable drum with modulating valve |
US3578817A (en) * | 1968-10-26 | 1971-05-18 | Gen Electric Canada | Control of mine hoist braking |
US4046162A (en) * | 1976-05-14 | 1977-09-06 | Deere & Company | Modulation control valve for clutches |
US4088305A (en) * | 1976-12-17 | 1978-05-09 | Caterpillar Tractor Co. | Brake-one way winch |
Family Cites Families (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4048799A (en) * | 1976-11-17 | 1977-09-20 | Caterpillar Tractor Co. | Winch control |
-
1979
- 1979-05-02 WO PCT/US1979/000293 patent/WO1980002446A1/en unknown
- 1979-05-02 JP JP50186279A patent/JPH025680B2/ja not_active Expired
-
1980
- 1980-04-02 EP EP19800301041 patent/EP0019352B1/en not_active Expired
- 1980-04-02 DE DE8080301041T patent/DE3068492D1/en not_active Expired
- 1980-04-30 SU SU802913948A patent/SU1074400A3/en active
Patent Citations (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR657612A (en) * | 1927-07-18 | 1929-05-24 | Vickers Electrical Co Ltd | Improvements to the braking devices of mobile devices or devices, in particular the mechanisms of winding, traction, extraction winches, etc. |
US2355749A (en) * | 1943-05-31 | 1944-08-15 | Polson Alexander David | Brake for hoist machinery |
DE1011132B (en) * | 1954-11-12 | 1957-06-27 | Siemens Ag | United driving and safety brake for conveyor machines |
US2912286A (en) * | 1957-03-29 | 1959-11-10 | New York Air Brake Co | Fluid pressure power brake system |
US3170543A (en) * | 1962-12-06 | 1965-02-23 | Goodyear Tire & Rubber | Delay valve |
DE1431991A1 (en) * | 1966-09-01 | 1969-07-10 | Gutehoffnungshuette Sterkrade | Operating device for the hydraulic braking device of a mining shaft hoisting machine or the like. |
US3463278A (en) * | 1967-11-02 | 1969-08-26 | Caterpillar Tractor Co | Transmission and brake for cable drum with modulating valve |
US3578817A (en) * | 1968-10-26 | 1971-05-18 | Gen Electric Canada | Control of mine hoist braking |
US4046162A (en) * | 1976-05-14 | 1977-09-06 | Deere & Company | Modulation control valve for clutches |
US4088305A (en) * | 1976-12-17 | 1978-05-09 | Caterpillar Tractor Co. | Brake-one way winch |
Also Published As
Publication number | Publication date |
---|---|
JPH025680B2 (en) | 1990-02-05 |
EP0019352B1 (en) | 1984-07-11 |
DE3068492D1 (en) | 1984-08-16 |
SU1074400A3 (en) | 1984-02-15 |
WO1980002446A1 (en) | 1980-11-13 |
EP0019352A3 (en) | 1981-02-18 |
JPS56500421A (en) | 1981-04-02 |
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