US 3762777 A
Description (OCR text may contain errors)
United States Patent .1191
Jacob 1 Oct. 2, 1973 1 DEVICE FOR CONTROLLING A WINCH PROVIDED WITH A SAFETY DEVICE  lnventor: Rene F. Jacob, Lagny Le Sec (oise),
France  Assignee: Societe Anonyme: POCLAIN, Oise,
France  Filed: Mar. 8, 1972 [211 App]. No.: 232,688
 Foreign Application Priority Data Mar. 17, 1971 France 7109417  US. Cl 303/22 R, 188/170, 303/11  Int. Cl Fl6h 57/10  Field of Search 303/10, 11, 13, 22 R; 188/170  References Cited UNITED STATES PATENTS 3,305,277 2/1967 Pickles et a1 303/11 X 3,472,560 10/1969 Desthuilliers 303/13 3,516,525 6/1970 Skaggs 188/17OX Primary Examiner-Allen N. Knowles Assistant Examiner-Michael Mar Att0rneyErnest A. Greenside  ABSTRACT This invention relates to the control of a winch connected to a hydraulic motor which pomprises two con; duits connected, the first to a source of pressurized fluid or to a discharge tank, the second to the tank or to the source, this control comprising a brake provided with a control member selectively connected by a third conduit to the source and to the tank. A calibrated valve is disposed on the conduit, downstream of the connection of the conduit to the delivery of the source.
This control is suitable for being adapted to the circuit for adjusting the position of the hook of a crane.
4 Claims, 4 Drawing Figures DEVICE FOR CONTROLLING A WINCH PROVIDED WITH A SAFETY DEVICE The present invention relates to a device for, controlling a winch provided with a safety brake.
Certain types of winches are already known which, when the control of the winch ceases to act, are immobilized by a safety brake.
ln hydraulically controlled winches, a hydraulic motor is coupled to the winch and has one of its chambers selectively placed in communication either with a source of pressurised fluid, or with a discharge tank. In this category of winches, the release of the safety brake is generally controlled by a jack, the feed of winch is connected to the main hydraulic circuit controlling the motor of the winch.
This state of affairs results firstly in that said jack, and, more generally, the member for controlling the safety brake, must be relatively large in order to develop a force under the effect of the lowest pressure of the fluid contained in the admission conduit of the motor of the winch, of sufficient value for releasing-the brake. lt is to be borne in mind that the lowest pressure referred to hereinabove, during the turning of the winch, occurs during the turning without load (for example when the hook of a crane rises empty, without suspended load). Another result, which is a secondary consequence of the preceding arrangement, is that the dimensions of the circuit for communicating the member controlling the brake with the discharge tank, during a braking, must also'be large, in order to create only reduced pressure drops when the fluid leaves said member, and thus in order to brake as quickly as possible.
In brief, the heretofore known embodiments necessitate choosing large control members for the safety brakes.
The invention intends to remedy this state of affairs, and to this end proposes a new winch controlling device. The hydraulic drive motor coupled with thewinch comprises two conduits connected respectively and selectively by means of an at least two-way distributor, the first to a source of pressurized fluid in the position of the distributor corresponding to. the turning of the winch, and to a discharge tank when the distributor is in its position opposite that corresponding to the turning, the second to the discharge tank and to the source of pressurized fluid, the control device, comprises a safety brake provided with a control member selectively connected, by a third conduit, to said source of pressurized fluid and to said discharge tank.
A calibrated valve is disposed on said first conduit,
downstream of the connection of said third conduit to.
the delivery of the source of pressurized fluid with respect to said source of pressurized fluid.
ln addition, when said distributor is in the position corresponding to the turning of the winch, the opening of said calibrated valve is advantageously controlled, by known means by the value of the pressure of the,
fluid contained in the part of the first conduit located downstream of said calibrated valve withrespect to. the source of pressurized fluid.
Finally, when the control device comprises in addition a speed limiter disposed on the firstconduit, and this speed limiter has a section of passage which is adjustable, when the distributor is in the position opposite that corresponding to the turning, asa function of the value of the pressure of the fluid contained in the second conduit, the calibrated valve is preferably constituted by said speed limiter.
The invention will be more readily understood upon reading the following non-limiting description with reference to the accompanying drawings, in which:
FIG. 1 is a schematic section of a first embodiment of adevice according to the invention;
FIGS. 2, 3 and 4 are schematic sections of a secon variant of a device according to the invention, but in three distinct positions of the control distributor of the winch.
Referring now to the drawings, the device shown in FIG. 1 comprises a winch which, in the present case, is referenced by its hydraulic drive motor 1. A safety brake is constituted by its brake lining 2, disposed opposite the winch. The lining 2 is articulated about the axis 3 and is normally maintained in abutment on the winch with the aid of an elastic holding member 4. A jack 5 is, furthermore, coupled between the structure 6, on which is mounted the winch and the lining 2. When the lower chamber 5a of the jack 5 is fed with pressurized fluid, said jack 5 develops a force opposite to that of the elastic member 4. It will be noted that the chamber 5b of the jack 5, opposite chamber 5a, is per manently connected to a discharge tank 7 by a conduit 8.
The motor 1 comprises two conduits 9 and 10, of which conduit 9 may constitute either the fluid admission or delivery conduit depending upon the direction of rotation of the winch. Thus when the winch turns in one direction, for example when the hook of the crane coupled to said winch rises conduit 9 acts as a fluid admission conduit and when turned in the opposite acts as a fluid delivery conduit, a conduit 10' is complementary of conduit9, that is, when conduit 9 delivers conduit 10 admits fluid and vice versa.
Conduits 9 and 10 are selectively connected to delivery conduit 11 of a pump 12, whose suction conduit 13 is connected to the discharge tank 7, and to said tank 7 by means .of a conduit 14, respectively, and vice versa, by means of a three-way distributor 15.
It will be noted that a valve 16, which comprises a calibrated spring 17, is in series connection with the conduit 9. The conduits 9 and 10 on the one hand and 11 and 14 on the other hand, are connected to the distributor 15 which ensures the following communicating connections: in its first position, the conduit 11 with conduit 14, by isolating conduits 9 and 10; in its second position, conduit 9 with conduit 11 and conduit 10 with conduit 14; finally, in its third position, the conduit 10 with-conduit 11 and conduit 9 with conduit 14.
A conduit 18 furthermore connects chamber 5a of the jack 5 to the delivery conduit 11 of the pump 12, while-a conduit 19, is connected between the conduit 18and'to the valve 16. Said valve 16 comprises a slide 20 -which is subjected to the oppositely directed forces imparted by the calibrated valve spring l7 and the pressure of the fluid contained in conduit 19.
The slide 20 of the valve 16 comprisesin addition a shoulder 21 capable of being displaced based the edge 22 of a groove 23 in the body 24 of the valve 16, while the part of the conduit 9, connected to the motor 1,
I, opens into said groove 23. The second part of conduit 9"which is'connected to the distributor 15, opens into asecond groove 25, also found in body 24. The slide 20 by virtue ofithe portion of shoulder 21 ensures either the isolation of two grooves 23 and 25 or communication therebetween by means of the section of passage constituted by the space between the edge 22 of the groove 23 and said shoulder 21, said section of passage having a value that varies from a'zero section to a section without pressure drop, adjusted as a function of the position occupied by the slide 20 which is balanced under the antagonistic actions of the spring 17, and of the pressure of the fluid contained in the conduit 19, said pressure acting on the face 26 of a piston 27 coupled to said slide 20.
An advantageous variant embodiment is shown in FIG. 2, in which the common elements of FIG. 1 are provided with the same reference numerals. What is noteworthy, in this embodiment, is the presence of one or more receivers, other than the motor 1 of the winch, which fed by a single pump 12. In this embodiment, a jack 28 is connected by conduits 29 and 30 to the feed circuit of the winch. To this end, a three-way distributor 31 is interposed in the delivery conduit 11 of the pump 12 between said pump and the distributor 15. A more detailed description of this modification is not deemed necessary since the use of additional distributors are well-known. Suffice it to say that in view of the jack 28 a two-way distributor 32 is interposed on the conduit 18. The slide of this distributor 32 is mechanically coupled, in the example shown, to the slide of distributor 15, so that there corresponds to the first position of distributor 15, in which the conduit 11 is placed in communication with the conduit 14, a first position of distributor 32, in which the parts of the conduit 18 located upstream and downstream of said distributor 32 are isolated from one another. Furthermore in the first position of the distributor 32 chamber a of jack 5 is connected to the tank 7 by a conduit 33.
It will be specified that the mechanical connection of the slides of the distributors and 32 is ensured by means of a cam 34 with two apices, separated by a notch 35, on which a roller 36 is in permanent abutment, mounted to rotate on a rod 37 integral with the slide of the distributor 32. The double-apex cam 34 is biased for movement with the distributor slide by means of rod 38, a spring 39 acting on distributor 32 for urging the roller 36 in abutment on the cam. In the arrangement of FIG. 2, the roller 36 is disposed in the notch 35 of the cam.
In the showings of FIGS. 3 and 4,-which respectively illustrate the slide of thedistributor 15 disposed in its second and third positions, the cam has been displaced with said slide of the distributor 15, so that the roller 36 is, in each of these two cases, disposed on one of the apices 34. The slide of the distributor 32 has therefore been urged rearwardly and is disposed in its second position, in which the conduit 33 connection at distributor 32 is broken while the conduit parts 18 are in communication and connect the chamber 50 of the jack 5 to conduit 11.
Another feature of the embodiment of FIGS. 2 to 4 will now be distributed. The conduit 19 has been eliminated, and instead a conduit 40, is connected on the one hand and between that portion of conduit 9 disposed between valve 16 and distributor l5, and on the other hand to the face 26 of piston 27. In addition, a supplementary groove 41 is provided in the body 24. In this embodiment the conduit 10 is separated into two parts the groove 41 being disposed therebetween. The piston 27 is furthermore distinct from the slide 20, with which piston 42 is integral. The face 43 of the piston 27, which is opposite face 26, is thus opposite the face 44 of piston 42. Furthermore, the face 44 of piston 42 is permanently subjected to the action of the pressure of the fluid contained in groove 41.
In FIG. 2, as well as in FIG. 1, it is to be noted that, with the distributor 15 disposed in its first position, the chamber 5a is placed in communication with the discharge tank 7, by conduits 18, 11 and 14 in one case, 18 and 33 in the other case. The elastic holding member 4 therefore acts alone on the lining 2 which is accordingly in firm abutment on the winch.
In FIGS. 3 and 4, the chamber 5a is on the on the other hand placed in communication, by conduit 18, with conduit 11. The action of the jack 5 in such circumstances overcomes the action of the elastic member 4, so that the lining 2 is separated from the winch.
In FIG. 2, the spring 17 of the valve 16 acts independently on the slide 20, which it urges to the right as viewed in the drawing thereby isolating the two parts of conduit 9.
In FIG. 3, the action of spring 17 is opposed by the pressure of the fluid acting on the face 26 of the piston 27. Consequently, a passage 45 is provided between the edge 22 of the body 24 and the shoulder 21 of the slide 20. The face 43 of the piston 27 is in abutment with the face 44 of the piston 42.
Finally, in FIG. 4, the action of the spring 17 is opposed by that of the pressure of the fluid on the face 44 of the piston 42. This same pressure has, moreover, pushed the piston 27 rearwardly as viewed in the drawing. A passage 46, is then provided between the edge 22 of the body 24 and the shoulder 21 of the slide 20. The pistons 27 and 42 are now separate.
The operation of the devices described will be apparent from the following.
Concerning first of all the device shown in FIG. 1, the distributor 15 may be disposed in one of its three positions.
In its first position, shown in this figure, the winch is isolated from the tank 7 and from the pump 12. The pump 12 discharges into conduit 11 which returns to tank 7, through the intermediary of distributor 15 and conduit 14. The pressure in conduit 11 is thus zero (except for pressure drops) and the pressure of the fluid in conduit 18 and in chamber 5a of jack 5 is therefore also zero. The brake lining 2 is accordingly in abutment with the winch under the action of the elastic holding member 4. Furthermore, the pressure in the conduit 19 is also zero so that, under the action of spring 17, the slide 20 is pushed back and isolates the two parts of conduit 9 from one another.
In its second position, the slide of the distributor 15 is pushed towards the right with respect to the position that it occupies in FIG. 1. The pump 12 with the distributor so displaced discharges into conduit 11, in the first part of conduit 9 and into the groove 25, which momentarily does not open out into groove 23. The pressure of the fluid therefore increases in conduit 11, as well as in conduits 18 and 19. The piston 27 is therefore acted on by the the pressure of the fluid on its face 26. The slide 20 moves towards the left, until a passage is provided between the edge 22 and the shoulder 21. The fluid in the groove 25 therefore passes through the passange into groove 23, and connects with the second part of conduit 9, to cause the motor 1 and, thus the winch, to rotate, the connection of the motor 1 is completed by conduit 10, distributor l5, conduit 14, leading to the tank 7.
With the connections just described, either the winch turns under load a (heavy mass lifted by the hook of a crane), or the winch turns without load (hook of the crane rising alone).
If the winch is under load, the pressure in the groove 23 and in the second part of the conduit 9 is high. The passage between the edge 22 and the shoulder 21 having been opened, remains open virtually without pressure drop, because the pressure is also high in conduits ll, 18 and 19. Under these conditions the pressure on the face 26 of the piston 27 overcomes the bias effect of the spring 17.
If, the winch is separated under no load conditions, a low pressure in the groove 23 and the second part of conduit 9 will suffice to cause the winch to turn. In this case, the pressure is relatively low in the groove 23 and falls, with respect to its initial value, in the first part of the conduit 9 and conduits 11, 18 and 19. The force on the face 26 of the piston 27 diminishes, and the spring 17 returns the slide 20 towards its initial position (towards the right). The passage between the edge 22 and the shoulder 21 is thereby narrowed, but not closed, and constitutes thereby a restriction with pressure drop: the value of the pressure in the groove 25 being higher than the value of the pressure in the groove 23. The pressure in the conduits l1, l8 and 19 is therefore stabilized to a value determined as a function of calibration of the spring 17. In the present case, whilst the pressure in the groove 23 is a few bars (for no load conditions), the spring 17 has been chosen so that the pressure in the groove 25 is equal to 50 bars.
The advantage of the device described resides in. In the previous embodiments, the pressure of a fluid in for example conduit 11 could only be 5 bars. Accordingly, to overcome the effect of the elastic member 4, a large section for jack 5 had to be provided which in consequence required within its chamber 50 a large quantity of fluid. When the winch was immobilized and the safety brake made operative, the fluid previously introduced into the chamber 5a had to be evacuated, this requiring, this provision of large section conduits for conduits 18, 11 and 14 in order to avoid counterpressures. With the device of FIG. 1, the pressure in the conduit 11 is never lower than 50 bars. In fact, either the pressure in the groove 23 is greater than 50 bars and that in the groove 25 is generally so, or the pressure in groove 23 is lower than 50 bars, and that in groove 25 is at least equal to 50 bars. This provides the advantage of the jack 5 section can be made ten times smaller than before, thus facilitating withdrawal of fluid from chamber 5a when braking is effectd. Braking is therefore effected more quickly than before and hence increases safety, not withstanding reduction of the size of the parts utilized in the device of the invention.
When, finally, the distributor 15 is in its third position, the fluid is admitted into the motor 1 through conduit 10, the flow path being completed by the part of the conduit 9 connected to groove 23. If the pressure in the conduits 11 and 10 is high (for example higher than 50 bars), the action of the pressure on the face 26 overcomes the bias of the spring 17. The passage thereby formed between the edge 22 and the shoulder 21 is without pressure drop and the delivery of the fluid of the motor 1 to the tank 7 is also effected without pressure drop. If, on the other hand the winch tends to race and drive the motor 1, the feed output of the said motor drops and the pressure in conduit 10 will be lowered, the same applying to as in conduits ll, 18 and 19. The spring 17 then pushes the slide 20 (towards the right) and restricts the passage between the edge 22 and shoulder 21. This passage then acts as a restriction which limits the output of the motor 1, and thus the speed of rotation of said motor 1 and the winch: It will thus be seen that the arrangement described provides speed limit control.
The device of FIG. 1 is of particular advantage when the pump 12 feeds only the winch. On the other hand, if another receiver, such the jack 28 of FIGS. 2 to 4 has also to be fed by pump 12, a momentary drop in pressure in the conduit 18 and consequently in conduit 19 may take place. To avoid this the pressure supplied for conduit 40 (see FIG. 2) is tapped from conduit 9 as connected between distributor 15 and valve 16 at a location close to the groove 25 so as not to be subject to the pressure fluctuations arising from feed of the jack 28.
FIG. 2 shows the distributor 15 in its first position, the jack 28 moreover not being supplied with fluid. The pump 12 delivers fluid 15 to tank 7 through conduit 1 l, the distributors 31 and 15 and conduit 14. The winch is not supplied with fluid, since the distributor 15 isolates the part of the conduit 9 connected to groove 25 and conduit 10. Moreover, the winch is braked, the lining 2 being in firm abutment on said winch, since the chamber 5a is in communication with the tank 7, by conduit 18, distributor 32 and conduit 33.
In the arrangement of FIG. 3, the winch turns (crane hook rising for example). If the winch turns under load, the pressure is high in groove 23 and consequently in the whole of conduit 9 and in conduit 40. The opening of passage 45 is thus large and brings about practically no pressure drop. Of course, the pressure in the conduits l1 and 18 is then also high. Hence, by the action of the jack 5, the lining 2 will be separated from the winch and the brake will released. If, on the other hand, the winch turns without load (hook alone), the pressure will be low in groove 23, but due to the pressure drop caused by the opening of the then restricted passage 45, the pressure in conduit 1 1 remains higher than a given value, for example 50 bars as previously mentioned. The jack 5 therefore continues to disables the brake of the winch.
Finally, in the arrangement of FIG. 4, the pressure in the groove 25 is practically zero (connected to the discharge tank 7) and can no longer actuate piston 27, by conduit 40. On the other hand, the feed pressure of the fluid contained in conduit 10 is high, when the motor 1 effectively drives the winch and when said latter does not race. The pressure of the fluid contained in the groove 41 therefore overcomes the bias effect of the spring 17 and maintains at a high value the pressue in the section defined by the passage 46 which is then not subjected to pressure drops. The fluid delivered into groove 23 by motor 1 accordingly flows without difficulty towards the tank 7. However under the effect of the load of the, a winch tend to race and drive the motor 1, the pressure in the conduit 10 drop and the pressure in the section 46 will also drop. The restriction of the passage opening limits the output of the motor 1 and thus also the speed of rotation of said motor, and acts thereby as conventional speed limiter, controlled by the pressure of the fluid in the conduit 10 for feeding the motor. The same speed limiting is applicable to the device shown in FIG. 1, albeit with a hydraulic control of the position of the slide 20, which is more direct and less sensitive to the possible variations in pressure in conduits 1 l and 18. Although for purpose of disclosure a single element has been described for use as a conventional speed limiter and for maintaining the pressure in section 25 at a given value (50 bars in the example chosen), it is obviously possible to provide these functions by two separate elements rather than the single element described.
Similarly, the coupling in the embodiments of FIGS, 2, 3, and 4 the slides of distributors 1S and 32 (which is advantageous from the point of view of simplicity of operation) is not to be construed limitatively since obvious variants could be resorted to.
What is claimed is:
1. Device for controlling a winch coupled with a hydraulic drive motor, which comprises at least a two way distributor, a discharge tank, a source of supply of pressurized fluid operatively connected between said distributor and said discharge tank, two conduits connected to said distributor for selective connection thereby between said discharge tank and said source of pressurized fluid, a third conduit operatively connected to said source of pressurized fluid and said distributor, a safety brake having a control member selectively connected by said third conduit to said source of pesssurized fluid and to said discharge tank, and a valve interposed in said conduit downstream of the connection of said third conduit with said source of pressurized fluid.
2. Control device according to claim 1, wherein with said distributor in one position thereof, during turning of the winch, the opening of said valve is controlled as a function of the pressure of the fluid contained in that part of the first conduit located downstream of said source of fluid.
3. Control device according to claim 1, wherein said valve comprises a limiter having a passage section which is adjustable as a function of movement ofa slide forming part of the valve.
4. Device according to claim 1, wherein said valve is a calibrated valve.