US2321880A - Hydraulic hoisting unit and control system therefor - Google Patents

Description

June 15, 1943. H. F. VICKERS. 2,321,880

HYDRAULIC HOISTIN G UNIT AND CONTROL SYSTEM THEREFOR 7 Sheets-Shet. 1

Or1gina1 Filed Sept. 22, 1933 I INVENTOR. 792/ 7 FI Z'ckers June 15, 1943;

H. F. VICKERS HYDRAULIC HOISTING UNIT AND CONTROL SYSTEM THEREFOR Origina1 Filed Sept. 22, 1933 7 ShqetS-Sheeg 2 INVENTOR.

jzm 71" Maker-6 ATTORNEYS HYDRAULIC HOISTiNG UNIT AND CONTROL SYSTEM THEREFOR I 7 Sheets-Sheet 3 June 15, 1943. H. F. vlc'KER s Original Filed se i. 22, 1953 2W, M v

June 15, 1943.

H. F. VlcK R's' v 2,321,880 HYDRAULIC HOISTING UNI T AflD'COIiTRQL SYSTEM THEREFOR Original Filed Sept. 22, 1953 7 sheets-sheet 4 INVENTOR. 95617719 W'Qkers I ATTORNEYS Juhe 15, 1943.

H. F. 'VQICKERS 2,321,880

HYDRAULIC HOISTING UNIT AND CONTROL SYSTEM THEREFOR Original Filed Sept. 22, 1933 '1 Sheets-Sheet 5 O O a o 8 N.

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m a h fi O a 3 w R 8 3 INVENTOR.

,F l/lcziers ATTORNEYS June 15, 1943. H. F; VICKERS 2,321,880

HYDRAULIC HOISTING UNIT AND QONTROL SYSTEM THEREFOR Original Filed'Sept. 22, 1935 7 Sheets-Sheet s INVENTOR.

June 15, 1 943. H."F. VICKERS J 2,321,880

HYDRAULIC HOI'STING UNIT AND CONTROL SYSTEM THEREFOR Originai Filed Sept. 22, 1933 v SheetsShe et v a 1! 3 Q4 v I n N I a a II- in w l a g xi N R i? "W 5 M INVENTOR. jyarry 7? kickers Potenterl June 15, 1943 UNITED HYDRAULIC HOISTING UNIT AND CONTROL SYSTEM THEREFOR Harry F. Vickers, Detroit, Mich, assignor to Vickers Incorporated, Detroit, Mich., a corporation of Michigan Original application Se No. 690,630, now Paton Divided and this applica- January 11, 1938.

ptember 22, 1028, Serial t No. 2,104,780, dated tioll January 7, 1938, Serial No. 183,883

6 Claims. (CI. 6053) This invention relates toa hydraulic hoisting unit and control system therefor, and has to do particularly with improved hoisting and lowering means in combination with positive and extremely safe controls together with improved accelerating and decelerating means relative to stai ting' and stopping position.

This application is a division of my copending application Serial No. 690,630, filed September 22, 1933, and matured into Patent No.. 2,104,780,

issued January '11, 1938. Reference is made to my application maturing into Patent No. 2,171,204 of August 29, 1939, which shows related subject matter.

An important feature of this invention has to do with a combined pump unit operating in combination with the control unit and the hoist motor and including a small volume pump continuously operable-to provide positive pressure for the control mechanism and a large volume pump operable only during the hoisting step, said two pumps being interconnected through a combined relief and balancing means, responsive to an increase in demand upon the large volume pump for allowing free flow from the small volume pump to the large volume pump line; resulting in the output of. the small volume pump being delivered to do useful work along with the output of the large pump.

Other novel features including the means for relieving the large pump of operating pressure,

Fig. 10 is a vertical sectional view taken on line iii-l8 of Fig. 7.

' Fig. 11 is an enlarged view of valve ii of Fig. 2. As best shown in Fig. l, the hoisting unit and control system include a two section pump unit generally indicated as'at 2, a control unit generally designated 3 including an auxiliary hand operated four way control unit or pilot valve of standard type, a motor and pump unit for the hoist generally designated 4, and a braking-or auxiliary hydraulically operated unit 5.

Referring particularly to the two section pump unit, as best illustrated in .Fig. 2 and designated X, this unit consists ofzalarge volume pump unit generally designated 8 and located adjacent the shaft coupling 1 which connects the pump unit with the initial source of power; and a small volume pump generally designated 8. Both pump sections are preferably positive displacement type pumps, the large pump, supplying pressure through the line 9 for directly controlling the hoisting unit and the small pump supplying pressure through the line III to control the brake and control valves (see Fig. 1).

As best shown inFig. 2, both pump sections 8 and 8 are connected'to a manifold Y having a common inlet II and branch conduits l2 and I3, respectively. The liquid under pressure from section 6 passes through the outlet 8a of the con- Fig. 1 is a flow sheet illustrating, somewhat slightly diagrammatic, the general combination v of the various elements going to make up the complete circuit.

Fig. 2 is a plan view mostly in section of the combined pump unit and particularly illustrating the combined relief and control valve.

Fig. 3 is a side elevation of the hoist unit and control mechanism.

Figs. 4 and 5 represent an end view and a partially cut away end view, respectively, of the hoist and control mechanism, andparticularly showing the braking mechanism and control therefor.

Fig. 6 is a sectional view taken on line 66 of Fig. 3 and showing particularly the volume control and directional control units.

Fig. 7 is a plan view of the structure shown in Figs. 3 to 5.

Fig. 8is a sectional view taken on line 8-8 of Fig. 7.

Fig. 9 is a fragmentary plan view taken on lines 9-9 'of Fig. 8 and being directed particularly to the balanced gear housing of the'hoist' unit,

nection Z and, as will be later described, the large pump 6 is relieved of operating pressure except during the actual hoisting operation. This results in a considerable power saving, as otherwise the single large volume pump would have to operate at full pressure at all times. flows through the small pump unit 8 into the chamber is, which chamber also surrounds a 4 valve i5 (see Figs. 2 and 11). The valve i5 is provided with a small piston l6, and the flow from the chamber l4, through the conduit a, to the right hand side of the piston l G is by means of a threaded resistance passage 15 formed between the parts Hand l8, the chamber to the left of the piston It being vented through the conduit i9 to make the pressure in the chamber to the right of the piston, designated 20, eflective. In practice there is no communication between the chamber at the left of the piston l6 and the conduit 19, there is enough clearance between the ends of the parts I! and I8 to assure drainage into the conduit l9.

As the pump 8 is continuously operated, the oil under pressure flows through the passageway and chamber i4 through the resistance passage l5 and into the chamber 20, exerting thrustito the left which tends to overcome an adjustable tension spring 2|. By overcoming the spring 2|, the pressure in the chamber causes the valve ii to move slightly to the left and take up a position whereby oil is by-passed into the chamber 22 Oil also which leads to the main operating passageway 90, in just suflicient amount to maintain a balance between the pressure in the chamber 20 and the resistance of the spring 2|, the oil being re' stricted in its-flow from the chamber M to the chamber 20 a proper amount to tend to maintain this balance; or, in other words, this restriction is suflicient to prevent chattering and sudden movement of the valve. This condition results in valve functioning as a relief valve during the time that the pressure in the chamber 22, and of course, the main outlet passage 90, is below the adjusted pressure of the spring 2|, with the result that a predetermined pressure is maintained in passageway and chamber H at all times so as to definitely assure operating pressure for the control parts of the system.

When thiscontrol pressure which flows from the chamber I4 through the line Hi to the unit 3a (see Fig. 1) is utlized to operate the control unit to hoist, the pressure in the outlet 9a and chamber 22 rises, causing a back pressure against the overflow of liquid flowing from the chamber |4, tending to further overcome the spring 2| and open the valve l5 from its normal correct position. In the function of this circuit we mayassume an adjusted operating pressure of five hundred pounds per square inch on the spring 2| and a.final operating pressure of seven hundred pounds o more in the outlet 90. and the chamber 22. When the main pump line 9 is so restricted as to exceed this five hundred pounds pressure, such pressure is delivered into chamber 29, with the direct result that this considerably exceeds the adjusted tension of spring 2|, causing the piston IS on the valve |5 to move to its extreme operating distance to the left, whereby allowing free flow of oil from the chamber H to the chamber 22. This results in the output of the small pump 8 being delivered to do useful work along with the output of the large pump 6.

The result and operation of this circuit under the above assumed condition is that pressure would be maintained in the chamber l4 at a. minimum of live hundred pounds per square inch, and pressure in the outlet 9a would vary from approximately zero to seven hundred or more pounds per square inch. It will thus be seen that this structure andcircuit permits a large volume of liquid being supplied to operate the motor at a relatively h gh operating pressure, and at predetermined intervals, and also maintainlng an operating pressure in the chamber H to assure a continuous pressure supply in the line In, which leads from the chamber M, to the pilot or operating valve 3a and to the braking unit 5. Referring particularly to thecontrol unit 3, as best shown in Fjigs. l and 6, it will be seen that the large volume pump assisted by the small volume pump supplies pressure through the line 9 and into the chamber 23 of the main control valve unit 3. This chamber 23 surrounds anautomatic volume control valve and also extends to a position where it surrounds andcommunicates with a directional control valve 25. A conduit 26 connects the control valve 311 with the left hand side of the direct onal control valve 25 so that, by movement of the control valve 3a, pressure is admitted from'the line In into the conduit 26 to shift the directional valve 25 to the right. This action permits oil to flow from the line 9, through chamber 23, intothe chamber 21, which chamber is connected through to Passage 28 which leads to. themotor 4.

The valve 24 is provided with a piston valve having a piston portion 29 which is provided with ends or piston rods on each side of equal diameter. The piston 29 is normally urged to the right by fa spring 30 of predetermined tension to normally prevent the flow of oil under pressure from the chamber 23 into the outlet passage 3| which leads to the return tank R. It will be seen that the valve 24 w ll remain on'its seat as long as the pressure in the chamber 23, communicated through passageway 32 to a chamber 33'at the left hand side of the piston 29, plus the predetermined thrust of the spring 30, is sufllcient to force all the pump output through the orifice, which is formed by the wall of the chamber 21 and the tapered portion 34 ofthe valve when the valve 25 is moved to the right, as viewed in Figs. ,1 and 6.

It should be noted here that, as shown in dotted lines in Fig. 1, the passageway 32 is directly connected with the chamber 21; the extreme right hand ofthe passageway 32'being in communication with the exhaust chamber 60 when the valve 25 is moved to the left, as will be later explained. By way of example, it will be seen that if the spring 30 back of the piston 29 has a thrust equivalent to twenty pounds per square inch. such piston w ll maintaina closed position relative to the passage 3|, until such time as the volume of liquid passing through the chamber 23 requires more than twenty pounds per square inch to force this volume of liquid through the clearance between the wall of the chambe 21 and the tapered portion 34 of the valve. It will I normally contacts with a cam follower 36 when such valve 25 is in neutral position. Movement of the valve to the right, as above described, also moves the cam 35 to the right which in turn permits the follower 36 to be raised because of spring pressure behind a valve or plunger 31 formed in an auxiliary portion 31) of the control unit 3. Raising of thisvalve 31 permits pressure to flow from the line Illa into line 39, which line 39 connects into a chamber or cylinder 39 forming a part of the automatic brake structure. As best shown in Figs. 4 and 5, this brake structure or looking unit consists of supported pivoted arms 40 and 4|. These arms and the brake shoe portions 42 carried thereby are normally forced against the brake drum 43 because of springs 44 so that normally the arms 40 and 4| grasp and hold the brake drum mechanically. The cylinder 39 is positioned intermediate the arms 40 and 4| and carries oppositely acting pistons 45, with the result that substantially simultaneously with the raising of the valve 31, the pressure from the line |0a will be communicated through the line I 38, into the cylinder 39 urging the pistons 45 outwardly to contact with and release the brake 1 directional valve 25 returning to neutral position,

connect the chamber 33'with the atmosphere or,

more specifically speaking," the return line, by

means of the conduit 45, conduit 45a connecting the cylinders of valves 31a and 31, and conduit, 45b connecting the cylinder of valve 31 with the.

relief or drain conduit 45.

, During the hoisting operation, the brake shoes being released by the application of pressureto the line 38, it willbe seen that this movement also supplies pressure to the bottom of the valve 310, overcoming the spring and moving this valve 31a upwardly and thus closing the exhaust vent so that during this period the chamber 33 is open to the efl'ective pressure from the line 32.

It will be seen that this construction and circuit are effective to positively relieve the large pump 5 from operating:pressure-except when hoisting. The hoisting unit 4, as shown in Fig. l, and better illustrated in Figs. 7 to 10, embodies a balanced gear motor of the general construction described in my Patent No. 1,937,367 of November 28, 1933.

. Teeth subjected to pressure in the pressure chamher at one side of the motor are balanced by pressure chambers 28a. and the teeth on the other side, namely those on the exhaust side being relieved by balancing chambers 3|a.

When the valve 24 is closed and the valve 25 moved'to the right to permit 'the'fiow of liquid under pressure into the conduit 25, the hoisting motor, generally designated 4, is actuated to the pressure in line'2 5 and-also results in applyingot pressure to the line 38 to operate the pistons and to relieve the brake shoes as previously described.

Duringthis lowering action, the motor 4 will operate as a pump and, referring to Figs. 1 and 6, it will be seen that oil in the passage 25 will fiow through a chamber 55 to a passageway 59 and due to the position of the valve 25, when moved to the left, will pass into passageway 55 connected to the reservoir. The connection between the chambers 55 and 59 is controlled by a valve 5| formed integrally with a piston 52. This valve "6| is normally urged to the right, as viewed in Fig. 6, by aspring 53 of predetermined tension; As best-shown in Fig. 1, chambers 54 and 55 are connected to passageway 59 by means of conduit 54a, thus permitting any pressure in passageway 59 to tend to overcome the tension of the spring 53, and in turn causing the valve 5 6| to restrict the passage of oil from the chamber 58 to the passageway 5.9.

An unrestricted passageway 56 directly connects the chambers and a (as shown in dotted lines in Fig.1) thus permitting the pressure. in passageway or chamber 50 to aid the spring 53 in resisting the effect of pressure in the passageway 59. In operation, during the lowering of the hoist, the piston 52 and valve 5| will take up a position wherein the difference in pressure existing in chamber 59 and chamber 50 will be equivalent to the resistance of the spring rotate the shaft 5iand the drum 55. As best shown in Figs. 1, 3 and 10,. the other end of this shaft 5| carries the brake member 43 and also a traveling nut 52, connected with arms 54 pivcited as at 53 to transmit motion to a sliding sleeve 55. This sleeve-55 surrounds an extension of. the valve 25.. A threaded'portion 524; which- 53 against fluid pressure in chambers 54. and 55.

A tapered surface .3411. at the opposite end of the valve from the tapered surface 34 will, when th valve 25 moves to the left, act as an orifice or throttling means between the chambers 59 operates the traveling nut 52 is provided with threads of such pitch, proportioned in accordance with the leverage of the arms 54 and the hoisting distance or -height so'that when the member being hoisted approaches the extreme limit .of such hoisting distance, the sliding sleeve 55 contacts with adjustable nuts 55 so that during-the last portion of the movement, the sliding sleeve 55 'will move the vvalve 25 towards central or' neutral position to gradually stop .the flow of liquid to the chamber '2'l from the chamber 23.

.,.This same movement depresses the plunger 3T and permits the valve 31a to lower to exhaust the chamber 33 to permit movement of the piston 29 to the left. Thus stopping movement of the motor 4 and also simultaneously cutting off the pressure from the line Illa and evacuating the chamber 39, allows thebrake springs to apply brake pressure and hold the hoist at the place where it" has just stopped; due 'tomovement of the directional control valve 25. The tendency to hoist by'the motor 4 isnot completely removed until after the brakes are applied; this is accomplished by using a spring backed valve 310 of less strength'than the back pressurebuilt up by thesudden exhausting of oil from the cylinder 39 by the springs 44.,

Movement of the control valve 3a in the'opposlte'sdirection eflects lowering of the elevator or hoist unit in that pressure from the small pump I is conducted through the line 51 to the chamber at the right of the valve 25 (see Fig. 1) to shift the valve to the left. This movement relieves and 59; Therefore, it will be seen that the balancing of the piston 52 and valve 5| determines a pressure drop across the orifice formed by the degree of taper between the surface 34a and the 3 wall of chamber. 59 resulting in a fixed flow rate v which in turn results in a fixed descending, rate for the elevator or hoist as explained above.

' and 34a may be diiferent,'dependent upon the It will thus be seen that different rates of hoisting and/or lowering can be obtained by the simple step of placing a new valve member 25 in the control unit having a taper 34 and 34a predetermined in accordance with .the particular hoist for which it is to be used; it being understood. of course, that thedegree of taper on "34 relative rate of hoisting, lowering, and decelerati n drsired in the particular job.

Descent of the hoist or elevator continues .until the traveling nut 52, moving in the opposite direction. actuates the sleeve 55 until contactis made with the adjusting nuts 51 and thus mov- .ing valve 25 toward neutral position, and gradually decelerating and then stopping the descent f the hoist or elevator. Cam 35 again lowers twmlujigerfibto exhaust cylinder 39 allowing the brakes to be applied to hold the hoist-injts st pped iorlocked position. The-conduit 32, see Fig. l, has a double funci h in thatit not only acts'in -assisting to maintain a constant head across the orifice formed bv thesurface 34 during hoisting, but also functions in combination with a valve to provide a maximum pressure control of the pump supply during hoisting. thereby providing maximum acceleration and control during the hoisting stroke. Referring more particularly to Fig. 6, the valve 68 includes a spring 59, the strength of which may be relatively adjusted by the mechanism 10 so that the spring 69 holds the valve member Ii on its seat until the pressure in the chamber 33 exceeds the resistance of the valve II and springs as. If the pressure in chamber 33 should develop sufiiciently to unseat the valve H, liquid will pass by said valve and through a drilled hole in the valve member 24 and piston 29, with the result that the valve 24 and piston will rapidly unseat to bypass the surplus oil to the tank. The valve 24 and piston 29 in this connectionact as a relief valve similar to the relief valve disclosed in my Patent No. 2,043,453 issued June 9, ,1936, inasmuch as the passageway 32 is formed smaller than the passageway 12 leading from thechamber 33 to the valve II. 'It is therefore obvious that the valve 24 acts as a non-chattering relief valve and that any increase in pressure in the 2,321,850 r N I I uid,-said lastnamed means being hydraulically controlled by fluid pressure from said small chamber 23 beyond the maximium pressure seating of the valve I I which controls the pressure in the chamber 33, will cause the valve 24 to unseat, allowing excess oil to pass from the chamber 23 to chamber 3| and to the return tank. Thus this valve acts both as a means for maintaining constant head across the fixed orifice and also as a relief valve for controlling maximum pressure.

When the valve 25 moves to the left, the taperd-portion 344; will uncover-the extreme right hand end of passageway 32 and open same to the exhaust conduit 60, unseating thevalve 24.

Attention is called to the important point that the combined relief and unloading valve permits the small volume pump to operate at the same pressure as the large volume pump, otherwise it would operate at a higher pressure during hoisting. v

It will thus be seen that the degree of taper 34 and 34a on the valve 25 will provide deceleration at any. rate desired, and in all cases will efl'ect'a smooth stop. The unloading valve 31a in combination with valve 31 effects release-oi the main pump only after pressure upon the locking mechanism has been released, to prevent powerrelease before the mechanical brake is set.

What I claim is:

1. In ahydraulic system, a large'volume actu' ating pump, a small volume control pump, acombined pressure and load control valve positioned between the outflow from the two pumps, and means for regulating the position between the valve and its seat to maintain a minimum pressure'in the exhaust from said control pump while the large volume pump is unloaded, said valve p mp. a combined pressure and load control valve positioned between the outflow from the two pumps, means for regulating the position of the valve and its seat to maintain a minimum pressure in the exhaust from said small pump and for controlling the flow of liquid from both of said pumps during the hydraulic actuation of said is actuated.

4. A hydraulic actuating system comprising a source of pressure supply including a relatively large volume pump and a relatively small volume pump, aahydraulic'motor'unit, means positioned between said pumps and said motor unit for controlling the flow and the direction of flow of "liquid, saidlast named means being hydraulically controlled by fluid pressure from said small pump, a combined pressure and load control valve positioned between the outflow from the two pumps, and means for regulating the position of the valve and its seat to maintain a minimum pressure in-the exhaust from said small pump and for controlling the flow of liquid from both of said pumps during the hydraulic actuation of said unit.

5. In a hydraulic power transmission system,

a large volume pump, a small volume pump, outbeing actuated by an increase in pressure in the large volume pump exhaust above the pressure in the small volume pump exhaust to permit the small volume pump to operate at the same pressure as the large volume pump.

2. In a hydraulic system, a large volume actuating pump. a small volume control pump, a combined pressure and load control valve positioned between the outflow from the two pumps whereby the outflow of said pumps will joinat a predetermined pressure, and means including surface re- 3 sistance means of suflicient length-and size tending to maintain the valve in balance angl prevent chattering by resisting sudden movement of the valve.

3. A hydraulic actuating system comprisinga source of pressure supply including a relatively large volume pump and a relatively small volume lets for each of said pumps and means joining said outlets, pressure receiving means connected to said outlets, and a-pressure and load controlling valve means positioned. between the outlets of said pumps comprising a valve movable to connect or disconnect said outlets in varying degrees, and means for regulating the position of said valve comprising a pressure responsive'ele- .ient primarily subject to outlet pressure 01 said small volumetpump and arranged to shii't said valve suiliciently to maintain a minimum pressure on said small pump and discharge excess volume into said large pump outlet, said element being alsc responsive to greater pressure than said minimum existing in the large pump outlet to fully connect said outlets and cause the load of said pressure receiving means to be borne by the two pumps.

6. In a hydraulic power transmission system,

- a large volume pump, a small volume pump, outlets for each of saidpumps and means joining said outlets, pressure receiving means connected to said outlets, and a pressure and load controlling valve means positioned between the outlets of said pumps comprising a valve movable to connect or disconnect said outlets in varying desure on said small pump and discharge excess volume into said large pump outlet, said element being also responsive, due to the opening of said valve by small pump pressure, to greater pressure than said minimum existing in the large pump outlet to fully connect-said outlets and cause the load of said pressure receiving means to be borne by the two pumps. HARRY F. VICKERS.

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