CA1226571A - Winch - Google Patents
WinchInfo
- Publication number
- CA1226571A CA1226571A CA000449455A CA449455A CA1226571A CA 1226571 A CA1226571 A CA 1226571A CA 000449455 A CA000449455 A CA 000449455A CA 449455 A CA449455 A CA 449455A CA 1226571 A CA1226571 A CA 1226571A
- Authority
- CA
- Canada
- Prior art keywords
- rope
- control
- working
- winch
- reel
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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Abstract
(57) Abstract of the Disclosure The invention is concerned with a winch device which comprises a working rope to be wound in onto a reel of its own for pulling or lifting a load as well as a control rope, likewise to be wound in onto a reel of its own, for controlling the operation of the winch. The invention is in particular concerned with a method for controlling the operation of the winch so that the working rope and the control rope are wound in, and can be wound out, respectively, in the same direction and at the same speed. According to the invention, this is accomplished so that a tendency is produced in the control rope to be pulled in, that the winding-in of the working-rope reel is caused by allowing the control rope to be pulled in over a certain advance distance relative the working rope, and that the speed of winding-in of the working rope is restricted, or the winding-in of the working rope is stopped, respectively, by restricting the winding-in of the control rope relative the winding-in of the working rope. In a winch device for carrying out the invention, the operation has been accomplished by means of friction couplings (15,29) that receive drive power as well as by means of rotational wedge members (4,32) controlling their connecting and disconnecting, res-pectively, the axial state of expansion of the said rotational wedge members being adjusted by means of the said relative ratio of movement of the control rope (45) and the working rope (48).
(Fig. 1)
(Fig. 1)
Description
Winch The invention is concerned with a winch device and in particular with a method for controlling the operation of the winch. In the present patent application, as an example off winch device in accordance with the application will be use a winch device used in forestry for harvesting of timber, the designation winch hying used for the said winch device in the following.
It is characteristic of such prior art winches as include a working rope and a control rope or cord for controlling the operation of the winch that the control rope must be tensioned or pulled outwards from the winch when the winch is supposed to pull the working rope into the winch. These winches known at present may be divided into two groups in respect of their principle ; of operation:
A simple winch started by tensioning the control Hope. The reel of the working rope can revolve freely unless the control rope has been tensioned. In order to couple such a winch so that it pulls, the control rope must be tensioned so that the operating connection between the working-rope reel and the power source of the winch is connected, whereupon the winch keeps pulling the working rope into the winch until the counter-force caused by the working rope exceeds the power transmitted by the operating connection. In a winch of this type, the operating connection may be produced, e.g., by means of a friction coupling con-trolled by means of the control rope, or by means of a corresponding drive gear. Thus, such a winch operates in accordance with the on/off principle, i.e. the hoistincJ is started my tensioning the control rope and stopped by slackening the control rope. If controlling of the pulling force of the winch is desired, that control must be performed by regulating tile compression I
force of the friction coupling, i.e. the tensioning of the control rope. In this winch type, the control rope moves little (e.g., 0.5 m) for the purpose of starting and controlling the hoisting, and even that in a direction opposite to the working rope, i.e., when the working rope is supposed to be wound into thy winch, the control rope must be kept tensioned by pulling it outwards from the winch and, correspondingly, in order to stop the hoisting, the control rope must be allowed to be slackened towards the winch.
As an example of the winch described above J
the winch it accordance with the Finnish Announcement Publication No. 50,405 can be mentioned. The hydraulic winches in use at present also operate by means of the same control principle. In these winches, the control of the valve opening and closing, respectively, the supply of oil to the hydraulic motor has been accom-polished so that the valve is opened when the control lever of the valve is tensioned, e.g., against a spring force, and that, correspondingly, the valve is closed by the effect of the said spring force when the control lever is released. If the operation a the control valve is supposed to be performed more remote from the winch, the operation of the said valve may be con-trolled, eye., by means of a control cord attached lathe control lever.
In the Finnish Patent 59,378, a winch is described whose operation is affected, besides by the tensioning of the control cord, also by its ~ovemerlt.
Such a winch possesses certain advantac3es, described in the said patent, aver the simpler winch described above. In that winch, e.g., the revolving angle of the working-rope reel can be controlled more accurately.
The winch is as such suitable, e.g., for loadLrlg a forest tractor if the hoisting distances are short, it in the case of long hoisting distances, the same problems are encountered as with the winch mentioned above.
it In this winch as well, the control rope moves in a direction opposite Jo the working rope, i.e., when the control rope is being pulled out of the winch, the winch pulls the working rope into the winch, and the other way round. Thus, both the working rope and the control rope, or at least one of them, are always outside the winch.
It is a problem of both ox the winch types mentioned above that, when the hoisting distance is long, the operator must handle a long control rope in -his hands and/ when he approaches the winch with the log, he must all the time reel out the control rope by hand, i.e. it must be kept tensioned. If the hoisting distance is, e.g., 40 metros and if the length of the control cord is the same, after the operator has hoisted the lo to the proximity of the winch, e.g. in accordance with the Finnish Patent 50,405, he has a skein of 40 metros of control rope in his hands. Thus, in practice, out of the above reason, the length of the control rope is limited to about ten metros, but that results in a new problem. If the length of the control rope is less than the hoisting distance, the operator must first attach the hoisting claws to the log and thereupon return to the control rope to start hoisting. However, in practice it often happens that when the working rope is tensioned, the hoisting claws slip off the log, and the operator must return to the log, attach the hoisting claws, go back to the control rope, etc.
In order to overcome these difficulties, a reeling device carried on -the back is at present used as an aid to some extent, which said device reels the slack control rope by means of spring force into the device. The reeling device is full of rope when the operator is alongside the winch, but it is emptied when he walks off the winch. The quantity of rope that can be reeled into the device is, however, rota-lively limitec1, and in practice the extreme limit: of I
its operation is often reached, at which time it can no longer deliver control rope. The reeling device is of some help, but the following deficiencies and drawbacks still remain:
The reeling device acco~nodates only about 30 to 40 metros of control rope, and if the log to be hoisted is more distant, the operator must take the reeling device off his back and, after he has attached the hoisting claws to the lo, he must return to the reeling device in order to start hoisting. When a - -winch is used, e.g., for harvesting wood in the cast of thinning out of the forest, the hoisting distances are often longer than the distance of operation ox the reeling device.
ennui the operator hoists the log and, at the same time approaches the winch together with the log, he must keep the control rope tensioned all the time, which means that he must reel the rope towards himself at least by the distance that he moves, and even more in the case of the winch types in which the control rope is placed on a reel revolving in a direction opposite to the working-rope reel.
The operator's walking along with the log to be hoisted may cause various dangerous situations, e.g.
when the operator happens to fall down during hoisting.
Thereat the control rope is most likely to be slackened, whereat, in the prior-art winch constructions, the consequence it that the operating connection pulling the working-~ope reel, such as the friction coupling, is opened. For example, in a steep upwardly slanting hillside, this results in the situation that the log may rush down the hill against the operator unless the winch includes a particular safety device to prevent such a situation. Such a safety device is also required by the law in certain countries.
It is an object of the present invention to avoid the above drawbacks and to provide such a methot3 I
_ 5 27370-for controlling a winch and such a winch by means of which the working becomes easier, faster, safer, and more convenient. In view of achieving the effects stated above, -the method in accord-ante with the invention is mainly characterized in that the winding-in of the working-rope reel is produced by allowing the control rope to ye pulled in relative to the working-rope and in that the speed of winding-in of the working rope is restricted or the winding-in of the working-rope is stopped respectively, by restricting the winding-in of the control rope relative to the winding-in of the working-rope. The winch invented for accomplishing the method is characterized in that the winch con-sits of a stationary hollow shaft supported on an appropriate frame construction, of a working-rope reel mounted at one end of the hollow shaft, revolving freely on the said shaft but having a restricted axial movement, of a connecting shaft passing through the hollow shaft and projecting out of both of its ends, the said connecting shaft being installed as freely revolving relative the hollow shaft, of a control-rope reel installed on the portion owe the connecting shaft projecting out of the end opposite to the working-rope reel, which control-rope reel. is arranged as substantially freely revolving on the connecting shalt and has a restricted possibility of axial movement relative the said shaft, of a secondary drive wheel installed on the hollow shaft between the working-rope reel and the con~rol-rope reel alongside the workin~-rope reel as freely revolving but a locked in respect of axle moment of a friction face between the workincJ-rope reel and the secondary drive wheel, of a rotational wedge member ~2~57~
- pa - 27370-5 between the locked end of the connecting shaft passing through the control-rope reel and the control-rope reel, of a rotational wedge member between the opposite Lockwood end of the connecting shaft and -the working-rope reel, of members for forcing the control-rope reel to revolve with a limited force relative the connecting shaft in the direction expanding the rotational wedge member that shifts the control-rope reel axially, as well as of members for forcing the connecting shaft to revolve along with the control reel.
The winch in accordance with the invention will be described in detail with reference to the attached drawing, without in any way restricting the winch in accordance with the invention to the construction in accordance with -the said drawing, because the winch in accordance with the invention can be accomplished in many different ways. In the drawing, Figure 1 is an axonometric view of a winch in accordance with the invention, partly in section, Figure 2 shows the rotational wedge member of the winch in accordance with the invention as viewed in the axial direction, Figure 3 shows the wedge member of Fig. 2 as viewed in a direction perpendicular to the axial direction, and Figure 4 is a sectional view of a part of the wedge member along line A-A in Fig. 2.
The winch device shown in Fig. 1 consists of a stationary hollow shaft 13 attached to an appropriate frame construction 19 as well as of a wor~ing-rope reel 7 and a control-rope reel 33, mounted on the said shaft 13 as freely revolving I
~22~ a - 5b - 27370-5 and having a limited axial movement, as well as of members, mounted on the said hollow shaft 13, for producing the driving power and for controlling the operation of the working-rope reel and the control rope reel relative -to each other.
One of the applications of use of the winch is operation as a timber hoist in forest conditions, in which case the winch is constructed so that it can ~,~
~2g~
be mounted to the three-point fastening gear of a tractor, and in such a case it receives its operating power from the power take-off of the tractor. The reeling power for the winch is transmitted by means of appropriate equipment (not shown) to a chain 47 and, by means of the chain, further to the drive or chain wheel 16. In the embodiment shown, the same equipment also transmits the operating power to the control equipment of the winch by the intermediate of a chain 46 and a cogwheel 25. - -At one end of the hollow shaft 13, theworking-rope reel 7 of the winch is installed as freely revolving on bearings 10, the working rope 48 that pulls or lifts the load being wound onto the said reel 7, and, correspondingly, unwound for the purpose of hoisting a new load. The journalling of the working-rope reel 7 has been accomplished so that the workiny-rope reel can move substantially freely but restrictedly, in a way to be described below, on the shaft 13.
A connecting shaft 1 is journal led inside the hollow shaft 13 as passing through it and projecting out of both of its ends. The connecting sheaf t 1 is con-centric with the hollow shaft 13, and it is journal led as freely revolving relative the hollow shaft 13. At the end of the connecting shaft 1 that projects out of the end of the hollow shaft 13 next to the working-rope reel 7, a locking nut 2 or equivalent has been fastened as the outermost component. Between this locking nut and the working-rope reel 7, the first rotational wedge member 4,5,6 is installed, whose purpose will be explail1ed later. At the opposite end of the connecting shaft 1, a locking nut 36 or equivalent has been fixed correspondingly and, inwards from the said nut 36, a rotational wedge member 31~32J35 corresponding to that mentioned above the purpose ox this second member being likewise explained later. Inwards from the rotational wedge member, on the Projecting portion of I
the connecting shaft 1, the control-rope reel 33 is mounted further, being freely revolving but having a restricted axial movement.
The said chain wheel 16 is mounted on the hollow shaft 13 as freely revolving, but as axially immobile relative the hollow shaft. The said chain wheel 16 is mounted alongside the working rope reel 7, at the side facing the control-rope reel 33, so that the working-rope reel 7 can reach contact with the friction face 15 on *he chain wheel 16 within the limits -of its axial movement. In the embodiment shown, the second said chain wheel 25 is mounted in connection with the control-rope reel 33, at the side facing the working-rope reel 7, so that the control-rope reel 33 can reach contact, by means of the members attached to the said reel 33, with the friction face 29 on the chain wheel 25 within the scope of its axial movement.
The second said chain wheel 25 is also journal led on the hollow shaft 13 as freely revolving but as locked in respect of axial movement.
The said members attached to the working-rope reel 33, which act jointly with the friction face 29 on the chain wheel 25, consist of drag members 26 fixed onto the control-rope reel 33 as well as of a clutch disc 30 attached to the connecting shaft 1 non notably but with a restricted movement in the axial direction.
In addition to the members described above, which are essential for the operation of the device, the device in accordance with the invention also includes a locking member 40, functioning as a safety device, which in certain operating situations locks the control-rope reel 33 against revolving in the direction of inward winding and, at the same time, causes stropping of the working rope reel. The con-struction and the operation of the safety c1evi~ebe descried below.
The operation of the winch can be described by means of the following example. It is assumed as a starting situation that the drive chains 46 and 47 receive operating power whereat the chain wheels 25 and 16 revolve in the direction indicated by the arrows, i.e. downwards at tile front side in Fig. 1. The working rope has been pulled out, and there is a load at its end. The control rope 43 is also in the pulled-out position, substantially at an equal distance as come 10 pared with the working rope 43. - -In this situation, if the control rope has been tensioned with a certain force so that the locking 40 is open and the winding-in of the control-rope reel is prevented by the tensioning force of the control lo rope, the rotational wedges 4 and 32 are in their narrowest positions in the axial direction, whereat the friction coupling 15 between the chain wheel 16 and the workiny-rope reel 7 is open and, likewise, the coupling between the clutch disc 30 and the friction coupling 29 is open. On the contrary, the control-rope reel 33 is in rubbing contact with the friction face on the chain wheel 25 by means of its ragging members 26.
Under these circumstances, the said dragging members cause a tendency in the control-rope reel to revolve I along with the chair wheel 25, i.e. in the direction winding the control rope inwards. The operator of the winch annuls this tendency by keeping the control rope tensioned in the way mentioned above In this situation, if no wishes that the workiny~rope reel 7 winds the working rope 48 inwards, he slackens the control rope 43 a little. 'Irrupt the control-rope reel 33 is trend being pulled by the drown members 26, in the direction of winding-in, i.e. the corltrol-rope reel 33 performs a little 35 bit of a revolution relative the collecting shaft: 1.
This revolving movement, on the other hind rockets in the circumstance that the rotational wedge member 32 expands in the axial direction and pushes the control-rope reel 33 in the axial direction towards the chain wheel 25 and the clutch disc 30. If the control-rope reel is allowed to revolve more in the same direction by slackening the control rope, a situation it reached in which the control-rope feel presses the clutch disc 30 against the friction face 29 on the chain wheel 25, whereat the connecting shaft 1 tends to revolve along with the control-rope reel 33.
On the other hand, a revolution of the con- - -netting shaft 1 in the direction of inward winding causes an expansion of the rotational wedge member 4 of the working-rope reel 7 in the axial direction, whereat this rotational wedge pushes the working-rope reel 7 towards the friction face 15 of the chain wheel 16.
When the connecting shaft 1 revolves sufficiently in the direction of inward winding, the friction coupling 15 is coupled and the working-rope reel starts revolving. If the winch operator, in this situation, delivers control rope to the winch without braking the inward winding of the rope at all, i.e. if the control rope is allowed to be wound in completely freely at its maximum speed of inward winding, the chain wheel 16, the working-rope reel 7, the connecting shaft 1, the chain wheel 25, the clutch disc 30, and the control-rope reel 33 revolve as a unit of the same speed, and the winch pulls the load towards the winch device. Both the working rope 48 and the control rope 43 are then wound in the same direction, i.e. inwards, and, if the 3Q diameters of the reels have been selected correctly, substantially at the same speed r which is an essential advantage of the invention as compared with the prior-art corresponding winches.
If the winch operator wishes to reduce the speed of winding in of the working rope or to stop the hoisting, he retards the winding-in of the control rope 43 to such an extent that eye control-rope reel 33 remains a little angular movement after, relative the connecting shaft 1. Thereat, the rotational wedge member 32 is returned in the axial direction correspond dingy in its narrowing direction, whereat the come press ion pressure between the control rope reel 33, the clutch disc 30, and the flaxen face 29 is reduced.
Thereby the clutch disc can slip yin the trailing direction relative the chain wheel 25, whereat the con-netting shaft 1 is no longer rotated at the same speed as in the earlier situation relative the working-rope reel 7, which also results in a slackening of the rotational wedge 4 A As a result of this, the friction coupling 15 starts slipping, whereat the winding-in of the working-rope reel 7 is retarded by the effect of the burdening load. When the movement is stopped completely by means of the control rope 43, the said friction couplings are opened to such an extent that the burdening force of the load and the force developed by the clutch 15 fully overrule each other, whereat the winding is stopped, but the load cannot flow backwards either.
In the operating model described above, it has been assumed, or the sake of simplicity, that in full-power winding-in the friction couplings are completely closed, i.e. non-slipping, but in practice, expressly in the winch application of the invention, it may be preferable that the speeds of revolution of the chain wheels 16 and 25 are selected high enough so that the friction couplings always slip to some extent.
After the load has been hoisted to the proximity of the winch, the operator detaches the toad and starts pulling the working rope 48 and the control rope 43 out of the winch. Thereat the control US rope must be pulled ahead of the jerking rope, whereat the friction couplings causing the winding-in are opened in the way described above. The only force opposed to ~26~i7~
the pulling out of the ropes remains the friction caused by the dragging members 26 between the control-rope reel 33 and the chain wheel 25, which friction is necessary for the starting again of the winding. In this situation as well, it is possible to reduce the burdening force generated by the dragging members 26 essentially by means of a particular feature of the in-mention without any harm to the winding function ox the winch. According to this particular feature, the winch has two sorts of dragging members 26. Some of them are long and resilient so that they extend onto the friction face 29 even when the control-rope reel is most distant from the chain wheel 25. On the other hand, others are shorter and more rigid than those mentioned above, whereat they do not reach contact with the friction face 29 until after the control rope reel 33 has been shifted a certain distance towards the chain wheel 25.
In this way, the resistance to revolving of the control-rope reel in the direction of winding-out can ye made low, and its winding-in can be made to start softly.
On the other hand, the rigid dragging members guarantee, at a later stage of starting of the winding process, strict following of the control reel along with the chair wheel 25, and consequently reliable connecting of the drive.
Another particular feature of the invention comes out ho means of the attached figures I, 3 and 4.
According to this particular feature, the wedge faces of the rotational wedge members have been shaped so that they have variable pitch When the rotational wedge starts operating out of its retracted position, i.e. when the components 4 in Fig. 3 tend to revolve relative each other, the pitch of the wedge faces 50 is steeply rising, whereat, at the final end of the operation of the rotational wedge members, the pitch of the wedge fact becomes more gently rising. Til~reby it is achieved that a slight movement at the initial AL
stage of the winding process between the control-rope reel 33 and the connecting shaft 1 as well as between the connecting shaft and the working-rope reel 7, ..
respectively, causes a strong axial expansion of the rotational wedge members, whereat any play movements slowing down the operation of the device can be elm-noted efficiently and the winding can be made to start rapidly. On the other hand, when the winding takes place at full power, the gently rising wedge faces guarantee a strong axial compression effect of the rotational - -wedge members and thereby guarantee non-slipping of the friction couplings. Correspondingly, by means of this arrangement, the winch can be made to be released efficiently when the ropes are being pulled out for the next hoisting cycle.
For the purpose of describing the construction and operation of the safety lock included in the winch, we shall come back to Fig. 1. The safety lock consists of a shaft fixed to the frame 19 of the winch, on which shaft a lever member 39 has been arranged as pivot able so that it is provided with two projecting cams. One of the cams. is provided with a pulley 42, over which the guide rope 43 is pulled. The opposite cam 40 is designed as a grasping member, which is arranged so as to engage in a tooth recess 34 provided at the end face of the guide-rope reel. The pivoting of the lever 39 in the direction engaging in the tooth recess 34 is caused by a spring member 44.
The objective of the said safety mender is to watch the tensioning of-the control rope 43 and to cause stopping of the hoisting if the tensioning of the control rope becomes lower than the value determined by the spring 44. Such a situation may occur, e.g., if the person operating tile winch falls Dwight during the hoisting in which case the control rope may become slack. Thereat, if the winch did not have the said safety member, there would be a risk that the luckily or Lo any other load resting on the working rope bruises the winch operator who fell down in the path of the load, for a slack control rope would mean a full-power hoist command for the winch.
On the contrary, by the effect of the safety device, when the tensioning of the control rope 43 becomes lower than the value set by meals of the spring 44, the cam 40 grasps the recess 34. Thereby the wlnding-in of the control-rope reel stops, which again results therein that the connecting shaft 1 and the -working-rope reel reach the control-xope reel locked in position. This again results therein that the rota-tonal wedge members become retracted and that the friction coupling acting upon the working-rope reel is opened. If, in this situation, the load happened to be, e.g., on a steep upwardly inclined hillside, it Waldo tend to pull the working rope outwards, it the working-rope reel 7 would tend to be wound open as pulled by the load. However, as the control rope reel is locked in its position by the effect of the rotating force produced by the chain wheel 25 and by the dragging members as well as by the effect of the locking effect produced by the cam 44, a relative move-mint is produced between the reels 7 and 33, which movement results in an axial reopening of the rota-tonal wedge members and in a coupling of the friction clutches so that the working-rope reel I having been stopped remains slipping on its friction clutch 15.
Should it happen at this stage further that the winch loses its drive power, in the winch in accordance with the invention t precautions can be taken for that situation 50 that the chain wheel 16, which transmits the drive power to the working-rope reel 7, is provided with a catch device which, at the hoisting stage, permits revolving of tune chain wheel in the direction of winding--l.n only. The said catch device is, however, not entirely indispensable, I
for in a situation in which the drive power of the winch it lost, reasonable security is obtained for the winch against winding back by making the catch toothing 34 on the control-rope reel 33 such that it grasps in both directions, whereat, when the control rope becomes slack, the control rope reel 33 is prevented from revolving in any of the directions. Thereby, when the working-rope reel 7 attempts to be wound out, the winch is wedged, owing to the opening of the rotational wedge members, and becomes a rigid unit, which is locked against windiny-out by the intermediate of the lever member 39 against the frame 19 of the winch.
In order to restart the winding in a situation in which the winch receives drive power, it is enough that the control rope 43 is tensioned against the effect of the spring 44 to such an extent that the cam 40 comes out of the recess 34, whereby the co~trol-rope reel can again revolve and the hoisting starts again By means of the winch construction described above, which is described as one embodiment of the method in accordance with the patent claim, the express advantage has been obtained, in view of the operation, that both the working rope and the control rope are always wound on the same direction, whereat, by means of correct choice of equipment, the speeds of winding can additionally be made substantially equal. Thus, the operator of the winch does not have to wind the control rope towards himself as he walks towards the winch when the hoisting makes progress. It is enough that he keeps the end of the control rope in his hand and walks towards the winch at his own speed. The winch itself takes care of the remaining of the control rope tensioned, i.e. winds it in at the walking speed of the operator, whereat, correspondingly/ owing to the control functions of the winch, the winding in of the working rope takes place substantially at the same speed at which the operator approaches the winch.
~2~5~7~
Besides thy fully mechanical exemplifying embodiment described above the control method in accordance with the invention may also be accomplished by means of winches of hydraulic or electrical operation.
Moreover, the winch in accordance with the invention may also be accomplished as a dual construe-lion in which the rope reels revolve in opposite directions, in which ease the winch gives a good embody-mint for a funicular drive.
It is characteristic of such prior art winches as include a working rope and a control rope or cord for controlling the operation of the winch that the control rope must be tensioned or pulled outwards from the winch when the winch is supposed to pull the working rope into the winch. These winches known at present may be divided into two groups in respect of their principle ; of operation:
A simple winch started by tensioning the control Hope. The reel of the working rope can revolve freely unless the control rope has been tensioned. In order to couple such a winch so that it pulls, the control rope must be tensioned so that the operating connection between the working-rope reel and the power source of the winch is connected, whereupon the winch keeps pulling the working rope into the winch until the counter-force caused by the working rope exceeds the power transmitted by the operating connection. In a winch of this type, the operating connection may be produced, e.g., by means of a friction coupling con-trolled by means of the control rope, or by means of a corresponding drive gear. Thus, such a winch operates in accordance with the on/off principle, i.e. the hoistincJ is started my tensioning the control rope and stopped by slackening the control rope. If controlling of the pulling force of the winch is desired, that control must be performed by regulating tile compression I
force of the friction coupling, i.e. the tensioning of the control rope. In this winch type, the control rope moves little (e.g., 0.5 m) for the purpose of starting and controlling the hoisting, and even that in a direction opposite to the working rope, i.e., when the working rope is supposed to be wound into thy winch, the control rope must be kept tensioned by pulling it outwards from the winch and, correspondingly, in order to stop the hoisting, the control rope must be allowed to be slackened towards the winch.
As an example of the winch described above J
the winch it accordance with the Finnish Announcement Publication No. 50,405 can be mentioned. The hydraulic winches in use at present also operate by means of the same control principle. In these winches, the control of the valve opening and closing, respectively, the supply of oil to the hydraulic motor has been accom-polished so that the valve is opened when the control lever of the valve is tensioned, e.g., against a spring force, and that, correspondingly, the valve is closed by the effect of the said spring force when the control lever is released. If the operation a the control valve is supposed to be performed more remote from the winch, the operation of the said valve may be con-trolled, eye., by means of a control cord attached lathe control lever.
In the Finnish Patent 59,378, a winch is described whose operation is affected, besides by the tensioning of the control cord, also by its ~ovemerlt.
Such a winch possesses certain advantac3es, described in the said patent, aver the simpler winch described above. In that winch, e.g., the revolving angle of the working-rope reel can be controlled more accurately.
The winch is as such suitable, e.g., for loadLrlg a forest tractor if the hoisting distances are short, it in the case of long hoisting distances, the same problems are encountered as with the winch mentioned above.
it In this winch as well, the control rope moves in a direction opposite Jo the working rope, i.e., when the control rope is being pulled out of the winch, the winch pulls the working rope into the winch, and the other way round. Thus, both the working rope and the control rope, or at least one of them, are always outside the winch.
It is a problem of both ox the winch types mentioned above that, when the hoisting distance is long, the operator must handle a long control rope in -his hands and/ when he approaches the winch with the log, he must all the time reel out the control rope by hand, i.e. it must be kept tensioned. If the hoisting distance is, e.g., 40 metros and if the length of the control cord is the same, after the operator has hoisted the lo to the proximity of the winch, e.g. in accordance with the Finnish Patent 50,405, he has a skein of 40 metros of control rope in his hands. Thus, in practice, out of the above reason, the length of the control rope is limited to about ten metros, but that results in a new problem. If the length of the control rope is less than the hoisting distance, the operator must first attach the hoisting claws to the log and thereupon return to the control rope to start hoisting. However, in practice it often happens that when the working rope is tensioned, the hoisting claws slip off the log, and the operator must return to the log, attach the hoisting claws, go back to the control rope, etc.
In order to overcome these difficulties, a reeling device carried on -the back is at present used as an aid to some extent, which said device reels the slack control rope by means of spring force into the device. The reeling device is full of rope when the operator is alongside the winch, but it is emptied when he walks off the winch. The quantity of rope that can be reeled into the device is, however, rota-lively limitec1, and in practice the extreme limit: of I
its operation is often reached, at which time it can no longer deliver control rope. The reeling device is of some help, but the following deficiencies and drawbacks still remain:
The reeling device acco~nodates only about 30 to 40 metros of control rope, and if the log to be hoisted is more distant, the operator must take the reeling device off his back and, after he has attached the hoisting claws to the lo, he must return to the reeling device in order to start hoisting. When a - -winch is used, e.g., for harvesting wood in the cast of thinning out of the forest, the hoisting distances are often longer than the distance of operation ox the reeling device.
ennui the operator hoists the log and, at the same time approaches the winch together with the log, he must keep the control rope tensioned all the time, which means that he must reel the rope towards himself at least by the distance that he moves, and even more in the case of the winch types in which the control rope is placed on a reel revolving in a direction opposite to the working-rope reel.
The operator's walking along with the log to be hoisted may cause various dangerous situations, e.g.
when the operator happens to fall down during hoisting.
Thereat the control rope is most likely to be slackened, whereat, in the prior-art winch constructions, the consequence it that the operating connection pulling the working-~ope reel, such as the friction coupling, is opened. For example, in a steep upwardly slanting hillside, this results in the situation that the log may rush down the hill against the operator unless the winch includes a particular safety device to prevent such a situation. Such a safety device is also required by the law in certain countries.
It is an object of the present invention to avoid the above drawbacks and to provide such a methot3 I
_ 5 27370-for controlling a winch and such a winch by means of which the working becomes easier, faster, safer, and more convenient. In view of achieving the effects stated above, -the method in accord-ante with the invention is mainly characterized in that the winding-in of the working-rope reel is produced by allowing the control rope to ye pulled in relative to the working-rope and in that the speed of winding-in of the working rope is restricted or the winding-in of the working-rope is stopped respectively, by restricting the winding-in of the control rope relative to the winding-in of the working-rope. The winch invented for accomplishing the method is characterized in that the winch con-sits of a stationary hollow shaft supported on an appropriate frame construction, of a working-rope reel mounted at one end of the hollow shaft, revolving freely on the said shaft but having a restricted axial movement, of a connecting shaft passing through the hollow shaft and projecting out of both of its ends, the said connecting shaft being installed as freely revolving relative the hollow shaft, of a control-rope reel installed on the portion owe the connecting shaft projecting out of the end opposite to the working-rope reel, which control-rope reel. is arranged as substantially freely revolving on the connecting shalt and has a restricted possibility of axial movement relative the said shaft, of a secondary drive wheel installed on the hollow shaft between the working-rope reel and the con~rol-rope reel alongside the workin~-rope reel as freely revolving but a locked in respect of axle moment of a friction face between the workincJ-rope reel and the secondary drive wheel, of a rotational wedge member ~2~57~
- pa - 27370-5 between the locked end of the connecting shaft passing through the control-rope reel and the control-rope reel, of a rotational wedge member between the opposite Lockwood end of the connecting shaft and -the working-rope reel, of members for forcing the control-rope reel to revolve with a limited force relative the connecting shaft in the direction expanding the rotational wedge member that shifts the control-rope reel axially, as well as of members for forcing the connecting shaft to revolve along with the control reel.
The winch in accordance with the invention will be described in detail with reference to the attached drawing, without in any way restricting the winch in accordance with the invention to the construction in accordance with -the said drawing, because the winch in accordance with the invention can be accomplished in many different ways. In the drawing, Figure 1 is an axonometric view of a winch in accordance with the invention, partly in section, Figure 2 shows the rotational wedge member of the winch in accordance with the invention as viewed in the axial direction, Figure 3 shows the wedge member of Fig. 2 as viewed in a direction perpendicular to the axial direction, and Figure 4 is a sectional view of a part of the wedge member along line A-A in Fig. 2.
The winch device shown in Fig. 1 consists of a stationary hollow shaft 13 attached to an appropriate frame construction 19 as well as of a wor~ing-rope reel 7 and a control-rope reel 33, mounted on the said shaft 13 as freely revolving I
~22~ a - 5b - 27370-5 and having a limited axial movement, as well as of members, mounted on the said hollow shaft 13, for producing the driving power and for controlling the operation of the working-rope reel and the control rope reel relative -to each other.
One of the applications of use of the winch is operation as a timber hoist in forest conditions, in which case the winch is constructed so that it can ~,~
~2g~
be mounted to the three-point fastening gear of a tractor, and in such a case it receives its operating power from the power take-off of the tractor. The reeling power for the winch is transmitted by means of appropriate equipment (not shown) to a chain 47 and, by means of the chain, further to the drive or chain wheel 16. In the embodiment shown, the same equipment also transmits the operating power to the control equipment of the winch by the intermediate of a chain 46 and a cogwheel 25. - -At one end of the hollow shaft 13, theworking-rope reel 7 of the winch is installed as freely revolving on bearings 10, the working rope 48 that pulls or lifts the load being wound onto the said reel 7, and, correspondingly, unwound for the purpose of hoisting a new load. The journalling of the working-rope reel 7 has been accomplished so that the workiny-rope reel can move substantially freely but restrictedly, in a way to be described below, on the shaft 13.
A connecting shaft 1 is journal led inside the hollow shaft 13 as passing through it and projecting out of both of its ends. The connecting sheaf t 1 is con-centric with the hollow shaft 13, and it is journal led as freely revolving relative the hollow shaft 13. At the end of the connecting shaft 1 that projects out of the end of the hollow shaft 13 next to the working-rope reel 7, a locking nut 2 or equivalent has been fastened as the outermost component. Between this locking nut and the working-rope reel 7, the first rotational wedge member 4,5,6 is installed, whose purpose will be explail1ed later. At the opposite end of the connecting shaft 1, a locking nut 36 or equivalent has been fixed correspondingly and, inwards from the said nut 36, a rotational wedge member 31~32J35 corresponding to that mentioned above the purpose ox this second member being likewise explained later. Inwards from the rotational wedge member, on the Projecting portion of I
the connecting shaft 1, the control-rope reel 33 is mounted further, being freely revolving but having a restricted axial movement.
The said chain wheel 16 is mounted on the hollow shaft 13 as freely revolving, but as axially immobile relative the hollow shaft. The said chain wheel 16 is mounted alongside the working rope reel 7, at the side facing the control-rope reel 33, so that the working-rope reel 7 can reach contact with the friction face 15 on *he chain wheel 16 within the limits -of its axial movement. In the embodiment shown, the second said chain wheel 25 is mounted in connection with the control-rope reel 33, at the side facing the working-rope reel 7, so that the control-rope reel 33 can reach contact, by means of the members attached to the said reel 33, with the friction face 29 on the chain wheel 25 within the scope of its axial movement.
The second said chain wheel 25 is also journal led on the hollow shaft 13 as freely revolving but as locked in respect of axial movement.
The said members attached to the working-rope reel 33, which act jointly with the friction face 29 on the chain wheel 25, consist of drag members 26 fixed onto the control-rope reel 33 as well as of a clutch disc 30 attached to the connecting shaft 1 non notably but with a restricted movement in the axial direction.
In addition to the members described above, which are essential for the operation of the device, the device in accordance with the invention also includes a locking member 40, functioning as a safety device, which in certain operating situations locks the control-rope reel 33 against revolving in the direction of inward winding and, at the same time, causes stropping of the working rope reel. The con-struction and the operation of the safety c1evi~ebe descried below.
The operation of the winch can be described by means of the following example. It is assumed as a starting situation that the drive chains 46 and 47 receive operating power whereat the chain wheels 25 and 16 revolve in the direction indicated by the arrows, i.e. downwards at tile front side in Fig. 1. The working rope has been pulled out, and there is a load at its end. The control rope 43 is also in the pulled-out position, substantially at an equal distance as come 10 pared with the working rope 43. - -In this situation, if the control rope has been tensioned with a certain force so that the locking 40 is open and the winding-in of the control-rope reel is prevented by the tensioning force of the control lo rope, the rotational wedges 4 and 32 are in their narrowest positions in the axial direction, whereat the friction coupling 15 between the chain wheel 16 and the workiny-rope reel 7 is open and, likewise, the coupling between the clutch disc 30 and the friction coupling 29 is open. On the contrary, the control-rope reel 33 is in rubbing contact with the friction face on the chain wheel 25 by means of its ragging members 26.
Under these circumstances, the said dragging members cause a tendency in the control-rope reel to revolve I along with the chair wheel 25, i.e. in the direction winding the control rope inwards. The operator of the winch annuls this tendency by keeping the control rope tensioned in the way mentioned above In this situation, if no wishes that the workiny~rope reel 7 winds the working rope 48 inwards, he slackens the control rope 43 a little. 'Irrupt the control-rope reel 33 is trend being pulled by the drown members 26, in the direction of winding-in, i.e. the corltrol-rope reel 33 performs a little 35 bit of a revolution relative the collecting shaft: 1.
This revolving movement, on the other hind rockets in the circumstance that the rotational wedge member 32 expands in the axial direction and pushes the control-rope reel 33 in the axial direction towards the chain wheel 25 and the clutch disc 30. If the control-rope reel is allowed to revolve more in the same direction by slackening the control rope, a situation it reached in which the control-rope feel presses the clutch disc 30 against the friction face 29 on the chain wheel 25, whereat the connecting shaft 1 tends to revolve along with the control-rope reel 33.
On the other hand, a revolution of the con- - -netting shaft 1 in the direction of inward winding causes an expansion of the rotational wedge member 4 of the working-rope reel 7 in the axial direction, whereat this rotational wedge pushes the working-rope reel 7 towards the friction face 15 of the chain wheel 16.
When the connecting shaft 1 revolves sufficiently in the direction of inward winding, the friction coupling 15 is coupled and the working-rope reel starts revolving. If the winch operator, in this situation, delivers control rope to the winch without braking the inward winding of the rope at all, i.e. if the control rope is allowed to be wound in completely freely at its maximum speed of inward winding, the chain wheel 16, the working-rope reel 7, the connecting shaft 1, the chain wheel 25, the clutch disc 30, and the control-rope reel 33 revolve as a unit of the same speed, and the winch pulls the load towards the winch device. Both the working rope 48 and the control rope 43 are then wound in the same direction, i.e. inwards, and, if the 3Q diameters of the reels have been selected correctly, substantially at the same speed r which is an essential advantage of the invention as compared with the prior-art corresponding winches.
If the winch operator wishes to reduce the speed of winding in of the working rope or to stop the hoisting, he retards the winding-in of the control rope 43 to such an extent that eye control-rope reel 33 remains a little angular movement after, relative the connecting shaft 1. Thereat, the rotational wedge member 32 is returned in the axial direction correspond dingy in its narrowing direction, whereat the come press ion pressure between the control rope reel 33, the clutch disc 30, and the flaxen face 29 is reduced.
Thereby the clutch disc can slip yin the trailing direction relative the chain wheel 25, whereat the con-netting shaft 1 is no longer rotated at the same speed as in the earlier situation relative the working-rope reel 7, which also results in a slackening of the rotational wedge 4 A As a result of this, the friction coupling 15 starts slipping, whereat the winding-in of the working-rope reel 7 is retarded by the effect of the burdening load. When the movement is stopped completely by means of the control rope 43, the said friction couplings are opened to such an extent that the burdening force of the load and the force developed by the clutch 15 fully overrule each other, whereat the winding is stopped, but the load cannot flow backwards either.
In the operating model described above, it has been assumed, or the sake of simplicity, that in full-power winding-in the friction couplings are completely closed, i.e. non-slipping, but in practice, expressly in the winch application of the invention, it may be preferable that the speeds of revolution of the chain wheels 16 and 25 are selected high enough so that the friction couplings always slip to some extent.
After the load has been hoisted to the proximity of the winch, the operator detaches the toad and starts pulling the working rope 48 and the control rope 43 out of the winch. Thereat the control US rope must be pulled ahead of the jerking rope, whereat the friction couplings causing the winding-in are opened in the way described above. The only force opposed to ~26~i7~
the pulling out of the ropes remains the friction caused by the dragging members 26 between the control-rope reel 33 and the chain wheel 25, which friction is necessary for the starting again of the winding. In this situation as well, it is possible to reduce the burdening force generated by the dragging members 26 essentially by means of a particular feature of the in-mention without any harm to the winding function ox the winch. According to this particular feature, the winch has two sorts of dragging members 26. Some of them are long and resilient so that they extend onto the friction face 29 even when the control-rope reel is most distant from the chain wheel 25. On the other hand, others are shorter and more rigid than those mentioned above, whereat they do not reach contact with the friction face 29 until after the control rope reel 33 has been shifted a certain distance towards the chain wheel 25.
In this way, the resistance to revolving of the control-rope reel in the direction of winding-out can ye made low, and its winding-in can be made to start softly.
On the other hand, the rigid dragging members guarantee, at a later stage of starting of the winding process, strict following of the control reel along with the chair wheel 25, and consequently reliable connecting of the drive.
Another particular feature of the invention comes out ho means of the attached figures I, 3 and 4.
According to this particular feature, the wedge faces of the rotational wedge members have been shaped so that they have variable pitch When the rotational wedge starts operating out of its retracted position, i.e. when the components 4 in Fig. 3 tend to revolve relative each other, the pitch of the wedge faces 50 is steeply rising, whereat, at the final end of the operation of the rotational wedge members, the pitch of the wedge fact becomes more gently rising. Til~reby it is achieved that a slight movement at the initial AL
stage of the winding process between the control-rope reel 33 and the connecting shaft 1 as well as between the connecting shaft and the working-rope reel 7, ..
respectively, causes a strong axial expansion of the rotational wedge members, whereat any play movements slowing down the operation of the device can be elm-noted efficiently and the winding can be made to start rapidly. On the other hand, when the winding takes place at full power, the gently rising wedge faces guarantee a strong axial compression effect of the rotational - -wedge members and thereby guarantee non-slipping of the friction couplings. Correspondingly, by means of this arrangement, the winch can be made to be released efficiently when the ropes are being pulled out for the next hoisting cycle.
For the purpose of describing the construction and operation of the safety lock included in the winch, we shall come back to Fig. 1. The safety lock consists of a shaft fixed to the frame 19 of the winch, on which shaft a lever member 39 has been arranged as pivot able so that it is provided with two projecting cams. One of the cams. is provided with a pulley 42, over which the guide rope 43 is pulled. The opposite cam 40 is designed as a grasping member, which is arranged so as to engage in a tooth recess 34 provided at the end face of the guide-rope reel. The pivoting of the lever 39 in the direction engaging in the tooth recess 34 is caused by a spring member 44.
The objective of the said safety mender is to watch the tensioning of-the control rope 43 and to cause stopping of the hoisting if the tensioning of the control rope becomes lower than the value determined by the spring 44. Such a situation may occur, e.g., if the person operating tile winch falls Dwight during the hoisting in which case the control rope may become slack. Thereat, if the winch did not have the said safety member, there would be a risk that the luckily or Lo any other load resting on the working rope bruises the winch operator who fell down in the path of the load, for a slack control rope would mean a full-power hoist command for the winch.
On the contrary, by the effect of the safety device, when the tensioning of the control rope 43 becomes lower than the value set by meals of the spring 44, the cam 40 grasps the recess 34. Thereby the wlnding-in of the control-rope reel stops, which again results therein that the connecting shaft 1 and the -working-rope reel reach the control-xope reel locked in position. This again results therein that the rota-tonal wedge members become retracted and that the friction coupling acting upon the working-rope reel is opened. If, in this situation, the load happened to be, e.g., on a steep upwardly inclined hillside, it Waldo tend to pull the working rope outwards, it the working-rope reel 7 would tend to be wound open as pulled by the load. However, as the control rope reel is locked in its position by the effect of the rotating force produced by the chain wheel 25 and by the dragging members as well as by the effect of the locking effect produced by the cam 44, a relative move-mint is produced between the reels 7 and 33, which movement results in an axial reopening of the rota-tonal wedge members and in a coupling of the friction clutches so that the working-rope reel I having been stopped remains slipping on its friction clutch 15.
Should it happen at this stage further that the winch loses its drive power, in the winch in accordance with the invention t precautions can be taken for that situation 50 that the chain wheel 16, which transmits the drive power to the working-rope reel 7, is provided with a catch device which, at the hoisting stage, permits revolving of tune chain wheel in the direction of winding--l.n only. The said catch device is, however, not entirely indispensable, I
for in a situation in which the drive power of the winch it lost, reasonable security is obtained for the winch against winding back by making the catch toothing 34 on the control-rope reel 33 such that it grasps in both directions, whereat, when the control rope becomes slack, the control rope reel 33 is prevented from revolving in any of the directions. Thereby, when the working-rope reel 7 attempts to be wound out, the winch is wedged, owing to the opening of the rotational wedge members, and becomes a rigid unit, which is locked against windiny-out by the intermediate of the lever member 39 against the frame 19 of the winch.
In order to restart the winding in a situation in which the winch receives drive power, it is enough that the control rope 43 is tensioned against the effect of the spring 44 to such an extent that the cam 40 comes out of the recess 34, whereby the co~trol-rope reel can again revolve and the hoisting starts again By means of the winch construction described above, which is described as one embodiment of the method in accordance with the patent claim, the express advantage has been obtained, in view of the operation, that both the working rope and the control rope are always wound on the same direction, whereat, by means of correct choice of equipment, the speeds of winding can additionally be made substantially equal. Thus, the operator of the winch does not have to wind the control rope towards himself as he walks towards the winch when the hoisting makes progress. It is enough that he keeps the end of the control rope in his hand and walks towards the winch at his own speed. The winch itself takes care of the remaining of the control rope tensioned, i.e. winds it in at the walking speed of the operator, whereat, correspondingly/ owing to the control functions of the winch, the winding in of the working rope takes place substantially at the same speed at which the operator approaches the winch.
~2~5~7~
Besides thy fully mechanical exemplifying embodiment described above the control method in accordance with the invention may also be accomplished by means of winches of hydraulic or electrical operation.
Moreover, the winch in accordance with the invention may also be accomplished as a dual construe-lion in which the rope reels revolve in opposite directions, in which ease the winch gives a good embody-mint for a funicular drive.
Claims (11)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. Method for controlling the operation of a winch or a corresponding device, which comprises a working-rope reel which can be connected in operating connection with a drive gear and disconnected from operating connection with the drive gear, respectively, and which winds the working-rope in and delivers the working-rope out, respectively, which controlling takes place by means of a control rope, which is wound into and wound out of, respectively, the winch, in which winch a tendency has been arranged for the control rope to be pulled into the winch, characterized in that the winding-in of the working-rope reel is produced by allowing the control rope to be pulled in relative to the working-rope and in that the speed of winding-in of the working-rope is restricted or the winding-in of the working-rope is stopped, respectively, by restricting the winding-in of the control rope relative to the winding-in of the working-rope.
2. Method as claimed in claim 1, characterized in that the winding-in of the working-rope is produced by allowing the control rope to be pulled in over a certain advance distance relative the working-rope and that the speed of winding-in of the working-rope is restricted, or the winding-in of the working-rope is stopped, respectively, by restricting the winding-in of the control rope relative the winding-in of the working-rope within the said advance distance so that the winding-in of the working-rope is retarded relative the lag distance of the control rope, or is stopped, respectively, after the lag of the control rope has become equal to the advance distance mentioned above.
3. Method as claimed in claim 1 or claim 2, characterized in that the tensioning of the control rope is being watched, that when the tensioning becomes lower than a predetermined value, stopping of the winding-in of the control rope is caused and, thereby, stopping or locking of the working-rope reel, and that restarting of the winding-in of the control rope and the working rope is caused by tensioning the control rope so that the tension exceeds the said predetermined value.
4. Winch for carrying out the method as claimed in claim 1, characterized in that the winch consists of a stationary hollow shaft supported on an appropriate frame construction, of a working-rope reel mounted at one end of the hollow shaft, revolving freely on the said shaft but having a restricted axial movement, of a connecting shaft passing through the hollow shaft and projecting out of both of its ends, the said connecting shaft being installed as freely revolving relative the hollow shaft, of a control-rope reel installed on the portion of the connecting shaft projecting out of the end opposite to the working-rope reel, which control-rope reel is arranged as substantially freely revolving on the connecting shaft and has a restricted possibility of axial movement relative the said shaft, of a secondary drive wheel installed on the hollow shaft between the working-rope reel and the control-rope reel alongside the working-rope reel as freely revolving but as locked in respect of axial movement, of a friction face between the working-rope reel and the secondary drive wheel, of a rotational wedge member between the locked end of the connecting shaft passing through the control-rope reel and the control-rope reel, of a rotational wedge member between the opposite locked end of the connecting shaft and the working-rope reel, of members for forcing the control-rope reel to revolve with a limited force relative the connecting shaft in the direction expanding the rotational wedge member that shifts the control-rope reel axially, as well as of members for forcing the connecting shaft to revolve along with the control reel.
5. Winch as claimed in claim 4, characterized in that the members for forcing the control-rope reel to revolve relative the connecting shaft are dynamic members and receive their drive power from the drive members of the winch.
6. Winch as claimed in claim 5, characterized in that the members for forcing the control-rope reel to revolve relative the working-rope reel consist of a chain wheel or equivalent mounted on the shaft alongside the control-rope reel as freely revolving, which wheel receives the drive power of the winch in the direction of winding in, of a friction face fired onto the side of the chain wheel facing towards the control-rope reel, as well as of dragging members attached to the control-rope reel and reaching contact with the friction face.
7. Winch as claimed in claim 6, characterized in that there are two pairs of dragging members, one of them being constantly in contact with the dragging face and the other pair not reaching contact with the said face until the rotational wedge shifting the control-rope reel axially expands.
8. Winch as claimed in claim 4 or claim 5 or claim 6, characterized in that the other rotational wedge member is placed between the working-rope reel and the locked end of the connecting shaft passing through the said reel.
9. Winch as claimed in claim 4, characterized in that the rotational wedges consist of bearing members which have races inclined in the same direction relative the plane perpendicular to the axial direction of the bearing member, the inclination of the said races becoming gentler in the rolling direction bringing the races farther away.
10. Winch as claimed in claim 4, characterized in that it is provided with members for locking the control-rope reel relative the frame of the winch against winding-in when the tensioning of the control rope goes below a certain pre-selected value.
11. Winch as claimed in claim 10, characterized in that the locking member consists of a tooth member stationarily fixed to the control-rope reel, of a lever member pivotably fastened to the frame of the winch, one of whose free ends is arranged so that it grasps a tooth recess of the tooth member, while the opposite end is arranged so that it feels the tension of the control rope relative a preset spring force, whereat the arrange-ment has been selected so that, when the tensioning force of the control rope becomes lower than the spring force, the lever member is locked in the recess and, correspondingly, is released from the recess when the tensioning force of the control rope exceeds the spring force.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000449455A CA1226571A (en) | 1984-03-13 | 1984-03-13 | Winch |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000449455A CA1226571A (en) | 1984-03-13 | 1984-03-13 | Winch |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1226571A true CA1226571A (en) | 1987-09-08 |
Family
ID=4127386
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000449455A Expired CA1226571A (en) | 1984-03-13 | 1984-03-13 | Winch |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1226571A (en) |
-
1984
- 1984-03-13 CA CA000449455A patent/CA1226571A/en not_active Expired
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| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |