US3887164A

US3887164A - Winch

Info

Publication number: US3887164A
Application number: US295973A
Authority: US
Inventors: William Charles Coombs
Original assignee: Individual
Current assignee: Individual
Priority date: 1969-11-21
Filing date: 1972-10-10
Publication date: 1975-06-03
Anticipated expiration: 1992-06-03

Abstract

This invention relates to a powered winch comprising in combination first and second rotatable drums and a cable tensioning means, said winch being such that in use a cable is pulled through the winch by said cable tensioning means acting on constantly differing adjacent portions of the cable which are always of the same length so that there is no increase in the length of cable within said winch, and said drums being offset relatively to one another so that said cable is in a straight line under minimum stress when it passes between said drums.

Description

United States Patent 1 [111 3,887,164 Coombs [4 *June 3, 1975 [54] WINCH 2,207,166 7/1940 Shepard 254/170 Inventor: William ar es coomb e 3,276,745 10/1966 Mauldtn 254/150 R 8 Iver, FOREIGN PATENTS OR APPLICATIONS Buckmghamsh're' England 832,058 7/1949 Germany 254/1751 Notice: The portion of the term of this Patet subsiequelllt 1990 Primary Examiner-Richard A. Schacher has been dlsclalmed' Assistant Examinerleffrey V. Nase 22 Filed: Oct 10 1972 Attorney, Agent, or FirmDowell and Dowell [2]] Appl. No.: 295,973

Related US. Application Data [57] ABSTRACT [63] Continuation of Ser. No. 89,942, Nov. I6, 1970. This inventifm relates to a Powered winch comprising in combination first and second rotatable drums and a 30 Foreign Application P igrfly D cable tensioning means, said winch being such that in Nov 21 1969 United Kingdom 5789/69 use a cable is pulled through the winch by said cable tensioning means acting on constantly differing adja- [52] U S Cl 254/1755 cent portions of the cable which are always of the [51] 366d 1 same length so that there is no increase in the length [58] Field 7 170 of cable within said winch, and said drums being offset 5 56 relatively to one another so that said cable is in a straight line under minimum stress when it passes be [56] References Cited tween Smd drums UNITED STATES PATENTS Johnston.......................... 254/175.5

3 Claims, 5 Drawing Figures FAIFNTHMHM m5 SHEET nvenlor mew WINCH This is a continuation, of application Ser. No. 89,942, filed Nov. I6, 1970.

This invention relates to an improvement in or modification of the invention claimed in U.S. Pat. No. 3,752,442. there is described and claimed a powered winch comprising a plurality of rotatable drums and a cable tensioning means, the winch being such that in use a cable is pulled through the winch by the cable tensioning-means after first engaging the drums, the cable tensioning means acting on constantly differing adjacent portions of the cable which are always of the same length so that there is no increase in the length of cable within the winch.

It has now been discovered that cable and winch wear can be reduced by off-setting one rotatable drum relative to another so that the cable can pass between the drums in a straight line and under minimum stress.

Accordingly, this invention provides a powered winch comprising first and second rotatable drums and a cable tensioning means, the winch being such that in use a cable is pulled through the winch by the cable tensioning means after first engaging the drums, the cable tensioning means acting on constantly differing adjacent portions of the cable which are always of the same length so that there is no increase in the length of cable within the winch, and the drums being off-set relatively to one another so that the cable is in a straight line under minimum stress when it passes between the drums.

Preferably, one of the drums is set squarely in the winch and the other drum is off-set in the winch. However, if desired, both drums can be off-set in the winch, so long as both drums are also off-set relatively to each other. When only one drum is off-set in the winch, this can be either drum. However, it is preferred that the drum which is first contacted by the cable when the winch is being assembled is set squarely in the winch housing and the other drum is off-set.

It has also been discovered that the cable can be fed directly into the winch without any necessity for manual reeving, if the cable is appropriately guided as it passes between the rotatable drums. Preferably, the drums are situated within a housing which has passageways formed in its interior for guiding the cable as it passes between the drums. The housing may be die cast and in this case, it is convenient to machine cable grooves in the winch housing from the exterior of the housing. A plate can then be screwed, bolted or otherwise fixed to the exterior of the housing to cover-up the grooves on the outside of the housing. Usually, the inside of the plate will be grooved so that when the plate is in position on the winch housing, a U-shaped groove is present in the housing opening out in the interior of the housing.

As an alternative to providing grooves in a housing of the winch, cable guides can project from the interior of the housing. Whilst such guides can be cast integrally with the winch housing, it is preferred that they be separate and attachable to the interior of the housing, for example, by screws, so that they can easily be replaced in the event of wear.

When the cable is not guided as it passes between the rotatable drums, the winches will usually be selfreeving and it will usually be necessary to manually reeve them. However, manual reeving is not a disadvantage as part of the winch is easily designed to be removable so that the manual reeving can take place. When the winch is set up, the said removable part can then be replaced. When the cable is guided the grooves or other form of cable guide will preferably extend in a line parallel to the longitudinal axis of the housing. The winches can be easily assembled during manufacture or after maintenance and, when the drums are turning, it is only necessary to gently push the cable into the winch for it to pass from one drum to another via the cable guides until it is gripped by the cable tensioning means, whereafter the cable tensioning means rapidly pulls the cable through the winch as will be explained in more detail hereinafter.

In order to facilitate the passage of the cable through the winch, a device such for example as a pressure roller may be provided at the entrance part of the winch. The device, for example, the pressure roller, may act to press the cable against the drum that is first contacted by the cable. The roller may be mounted on a spindle between supporting arms. The roller may be so mounted on a linkage that it will press against the first drum with a pressure which increases with the weight which the winch is supporting.

The periphery of the rotatable drums will usually be grooved so that the cable is in contact with a relatively large surface area of the drums. In this case, one drum is off-set by one complete pitch which will be approximately equal to the diameter of the cable plus the thickness of one flange ofa groove in the drums. The cable will be under minimum tension between drums because it will be in a straight line. This not only prolongs the life of the cable but means that less strain is placed on the drum axes and other parts of the winch. The cable grooves on one drum will be off-set with respect to the cable grooves on another drum and all aligning of the cable is done whilst it is passing around the drums, i.e. at a time when the cable is under less stress than when it is between drums.

Preferably, the two rotatable drums are both driven at the same rotational speed.

The cable tensioning means is preferably a pressure plate, for example a multi-spring biased pressure plate similar to a swash plate. The pressure plate rotates whilst gripping the cable and thus maintains the cable under tension and pulls it through the winch. The pressure plate is preferably fixed to the drum that is first contacted by the cable when the winch is assembled, the other drum preferably being offset.

The rotatable drums may ultimately be driven by any one or more power sources such for example as an electrical or petrol motor. The size of the motor will of course vary with the size of the winch and can be of 3 horse power for a relatively large winch or of from 1 to W2 horse power for a smaller winch. There may be two or more reduction stages between the power source and the drums if desired.

When two reduction stages are employed, the first reduction may be, for example, 2%:1 and may be accomplished by mating a toothed wheel directly driven by the power source with a bevel gear. The second reduction may be, for example, :l and may be accomplished by mating the bevel gear with a final drive to the rotatable drums.

A number of mechanical arrangements may be employed in the drive arrangement for the rotatable drums. For example, each drum can be supported on a separate shaft and each shaft can be provided with a worm wheel with a common worm extending between the worm wheels. This common worm can be driven by the bevel gear when it is employed. Alternatively, when only one of the rotatable drums is off-set, each drum shaft can be provided with a skew bevel gear and there will be a common pinion acting as an idler together with a worm and worm wheel on the squarely set drum. A still further alternative arrangement employs a worm and worm driving wheel on one drum shaft with a sprocket and chain arrangement leading to the other drum shaft the sprocket being mounted on a swash plate.

Preferably, there will be three cable grooves on the first drum that is first contacted by the cable and three cable grooves on the other or second drum. A fourth cable groove is formed between the first drum and the pressure plate, with one flange of the groove being on the first drum and the other flange of the groove being on the pressure plate. Preferably, the first groove on the first drum is twice as wide as the other grooves on the said first drum so that the cable does not enter the winch and be abruptly brought into an appropriate position to pass to the first groove on the second drum.

The cable will normally enter the winch from one side at a point which allows it to easily pass around the said double width groove in the first drum. The cable will normally pass nearly twice around the first drum in the double width groove without overlapping itself. It will then leave the double width groove at the top and will pass to the top of the first groove on the second rum. The cable will pass around the far side of the second drum and will leave the first groove in the second drum at the bottom of the second drum and will pass to the second groove in the first drum at a point which is at the bottom of the first drum. The cable leaves the said second groove at a point which is at the top of the first drum. The process is repeated until the cable enters the groove formed between the first drum and the pressure plate. It is allowed to make approximately three-quarters of a turn in this groove before it is picked off the pressure plate groove and passed through an outlet in the winch. Obviously, it is necessary to pick the cable from the pressure plate groove since otherwise it would make a complete revolution in the pressure plate groove and would foul up on itself.

Various devices may be used to pick the cable from the first drum/pressure plate groove. A presently pre ferred device is a steel pick-off which is retained in a housing. The housing is provided with a passageway for the cable as it is picked from the first drum/pressure plate groove by the steel pick-off and the passageway is appropriately curved to joggle the cable past that part of the cable entering the first drum/pressure plate groove at the bottom of the said groove. The cable leaves the pick-off housing and the winch housing and dangles from the winch if the winch in climbing the ca ble.

The pick-off housing can be made of any appropriate material that will not be too easily worn by the cable and will itself not too readily wear the cable. Suitable low friction materials include nylon and polytetrafluoroethylene. Advantageously the materials can be selflubricating materials or a lubricant can be provided. The pick-off housing will usually be entirely made of the material chosen but, if desired, a metal housing can be die cast and then coated with a material such for example as Teflon or Fluoron.

The winch exterior can be provided with an aperture through which the pick-off housing can pass. This facilitates winch assembly and enables the pick-off housing to be easily replaced in the event that it becomes impaired by wear. When the pick-off housing is in position in the winch, the aperture in the winch exterior can be closed by an appropriately sized plate which can be screwed, bolted or otherwise fixed to the winch extenor.

If desired the winches may be provided with cable guiding means for guiding, the cable at an appropriate angle to the rotatable drums. The winches may also be provided with further cable guiding means for guiding the cable as it leaves a winch via the cable tensioning means and pick-off housing.

Although the winches are presently constructed to have a safety factor of 18:1, they preferably include one or more safety devices. Thus, for example, the drive from a first reduction stage to the final drive for the drums may act through an infinitely variable torque limiter which acts to save overloading and may be set, for example, at 1200 lbs. The winches may also be fitted with a sensing device which prevents winch operation, except for cable winding, when there is no load on the winch, for example, when the winch is caught on a window sill and the operator is still trying to lower the winch. A presently preferred sensing device is a spring loaded microswitch operated by slack cable within the winch.

Safety devices to operate in case any part of the winch should fail when it is in use may include a dead mans handle and/or a mechanical cable gripping device. The dead mans handle will usually operate such that when it is released from the grip of an operator it will return to a position which causes the power supply to the winch to be cut off and a brake applied. The mechanical cable gripping device may be attached to the upper part of the winch.

Most of the various winch components may be housed within a cover. However, usually, the electric motor which may constitute the power source will be attached to the outside of the casing. The winch will normally be provided with appropriately apertured lugs or other suitable means by which it can be quickly and easily attached to staging.

The various driving components of the winches should be well lubricated to minimize wear but lubricant should not be present on the cable or cablecontacting surface of the drums and pressure plate since a high coefficient of friction is desired. Accordingly, it has been found desirable to encase the drive part of the winch so that it can be lubricated. When the drive part of the winch is encased, the said drive part can run in an oil bath if desired. The casing may be provided with one or more conduits for introducing lubricant. If desired, the winches may be provided with a cam arrangement which drives an oil pump for effecting the lubrication.

In order that the winches may be as light as possible, it is preferred to manufacture some of the winch parts from an aluminium alloy. For example, the rotatable drums may b: made from a heat treated aluminium alloy. If desired, the rotatable drums can be made of steel, preferably high tensile, heat treated steel. Usually, the drums will be hollow to provide for a minimisation in weight and cost.

An embodiment of the invention will now be described by way of example with reference to the accompanying drawings, in which:

FIG. 1 is a top plan view of a winch in accordance with the invention;

FIG. 2 is a section on the line I] ll shown in FIG.

FIG. 3 is a section on the line III Ill shown in FIG.

FIG. 4 is a view on the arrow IV shown in FIG. I, with the cover of the winch removed, and

FIG. 5 is a view on the line V V shown in FIG. 1.

Referring to the drawings, the winch comprises a first rotatable drum 2 and a second rotatable drum 4. The exterior surface of the drum 2 is provided with three cable receiving tracks 6 and the exterior surface of the drum 4 is provided with three cable receiving tracks 8. The first cable receiving track 6A on the drum 2 is twice the width of the other two tracks 6 so that the cable can be gently brought to a position in which it can pass in a straight line to the first track 8.

The winch has a back plate 10 of substantial thickness and this back plate 10 supports many of the winch components. Thus, as most clearly seen from FIG. 2, the back plate 10 is provided with an aperture 12 through which passes a spindle 14. The spindle 14 may be partially hollowed out if desired and rotates in the two halves a bearing 15 in the aperture 12. The bearing 15 is formed in two halves because it has two outer flanges 15A and 15B and it would otherwise not be possible to insert the bearing in the aperture 12. A lockable flanged nut 13 screws onto the spindle l4 and presses against the flange 15B to maintain this half of the bearing in the aperture 12. The distance between the two bearing halves forms an oilway 17.

The spindle 14 is provided with a keyway 16 which receives a key 18 projecting from the inside of the drum 2. Thus, the drum 2 is keyed to the spindle 4.

The spindle 14 is also provided with a second keyway 20 which receives a key 22. The key 22 projects from the inside of a worm wheel 24. A housing 26 is joined to the wall 10 by nuts 28 and bolts 30 and the front wall 32 of the housing 26 is provided with an internal annular boss 34. One end of the spindle 14 rotates in a bearing 36 in the boss 34.

The worm wheel 24 and the drum 2 are held in position on the spindle 14 by means of a flange or nut 38 fixed to one end of the spindle 14. The flange or nut 38 abuts against the centre face 40 of the drum 2 and is held in this position by a locking nut 42 which screws over a screw threaded part at the other end of the spindle 14. The locking nut 42 is maintained in its tightened position by a washer 44 which bends around the nut 42 at 46. The locking nut 42 can be screwed along the spindle l4, pushing before it the worm wheel 24, to ensure that the worm wheel 24 is correctly positioned with respect to a worm 82 (see FIG. I). The configuration of the spindle 14 is most clearly seen from FIG. 2 and allows the worm wheel 24 to be spaced from the drum 2 whilst the spindle fits tightly in the bearing 15 in the aperture 12 in the back plate 10. The numeral 19 indicates a rotatable distance washer which separates the drum 2 from the bearing 15.

A toothed pulley wheel 48 is attached to the drum 2 by means of screws 50 which screw into the drum 2. A

belt 52 (FIG. 1) passes around the pulley wheel 48 to another similarly toothed pulley wheel 54. Thus, rotation of the pulley wheel 48 is transferred to the pulley wheel 54 by means of the belt 52. Obviously, instead of using a belt, a chain or a gear arrangement can be used if desired.

It will be seen from FIG. 1 that the drum 2 is mounted squarely in the winch and is perpendicular to the back plate 10. In contrast, the drum 4 is tilted outwardly with respect to the back plate 10 so that the distance between the drum 4 and the back plate 10 is greater at the top of the drum 4 than at the bottom of the drum (FIG. 3). Thus, the drum 4 is off-set with respect to the drum 2 and the amount of off-setting is sufficient to enable the cable 56 to pass in a straight line between the two

drums

2, 4.

The drum 4 is mounted at its off-set position about a spindle 58 as shown in FIG. 3. The spindle 58 is fixedly mounted in an inwardly and slightly downwardly projecting annular boss 60 formed integrally with the back plate 10. An annular bearing 62 fits around the middle of the spindle 58 and the drum 4 rotates on the bearing 62.

The pulley wheel 54 is fixed to one face of the drum 4 by means of screws 64 which screw into the drum 4.

The two

drums

2, 4 are enclosed by a thin metal casing 66 which is in two halves. One half 66A is hinged to the back plate 10 by a hinge 68 and the other half 66B is hinged to the back plate 10 by a hinge 70. The two halves 66A and 66B of the casing 66 open at a midpoint 72 and swing wide open to fully expose the

drums

2, 4 and allow the cable to be manually reeved through the winch. The reeving is a relatively simple operation and when the reeving has been completed, the two halves 66A and 66B of the casing 66 can be swung to their closed position as shown in FIG. 1 and secured together by a lock or latch (not shown).

It will be noted from FIG. I that the casing 66 presses lightly against the cable 56 as it passes around the outer surfaces of the

drums

2, 4. This slight contact between the casing 66 and the cable 56 is not sufficient to cause undue drag or cable or casing wear. However, it is sufficient to help maintain the cable 56 in the

grooves

6, 8 during use of the winch. Also, after reeving, if the cable is not correctly in the

grooves

6, 8 the casing 66 cannot be shut, thus indicating that the reeving has not been correctly carried out. This provides an early warning that the reeving requires re-doing and so prevents the cable from fouling in the winch as would be the case if the cable was incorrectly reeved and the winch put into operation. Because of the fact that the drum 4 is off-set relatively to the drum 2 and the back plate 10, it will be appreciated that the casing 66 cannot be truly circular if it is to contact the cable over about three-quarters of its passage around the

drums

2, 4 and the casing then has to be slightly distorted. Alternatively, if the casing 66 is to be truly circular, the inside of the casing which is to contact the cable 56 around the drum 4 may be provided with an inwardly projecting cable contacting surface.

The winch drive is comprised by an electric motor which has only been shown in outline for simplicity since any power source could be used. The electric motor 74 has a vertical drive shaft 75 (FIG. 3) which drives a first gear 76. The gear 76 meshes with and drives a gear 78 and the gear 78 meshes with and drives a gear 80. It will be seen that the gear 76 is smaller than the gear 78 and that the gear 78 is smaller than the gear 80. Thus the gears 76, 78, 80 form a reduction gearing system from the electric motor 74 to the worm 82 which is attached to the gear 80. The worm 82 may be mounted on a mounting plate 85.

The teeth on the worm 82 mesh with the teeth on the worm wheel 24, causing the worm wheel 24 to rotate. As explained above with particular reference to FIG. 2, the worm wheel 24 is keyed to the shaft 14 so that rotation of the worm wheel 24 is transferred to the shaft 14. The gears 76, 78, 80, the worm 82 and the worm wheel 24 may run in an oil bath ifdesired and, in this case, the winch will be provided with appropriate oil seals. The shaft 14 is keyed to the drum 2 so that rotation of the shaft 14 is transferred to the drum 2. The pulley wheel 48 rotates with the drum 2 because it is screwed to it by the screws 50.

Rotation of the pulley wheel 48 causes the belt 52 to rotate and thereby drive the pulley wheel 54. Because the pulley wheel 54 is fixed to the drum 4 by the screws 64, the drum 4 is also caused to rotate about the bearing 62 on the spindle 58.

As indicated previously, the drum 2 has three cablereceiving tracks 6 and the drum 4 also has three cablereceiving tracks. A fourth cable receiving track 83 is formed on the drum 2 by means of a pressure plate 84 shown in FIG. 2. The pressure plate 84 is attached to the drum 2 by screws or bolts 86 which screw into apertures 89 in the pressure plate. The screws or bolts 86 are each surrounded by a spring 88 which fits within a housing recess 90 in the drum 2. One end of the spring 88 rests on the bottom of the recess 90 and the other end of the spring 88 presses on a washer 92. The pressure plate thus presses against the drum 2 (or a cable in the track 83) with a pressure dependent upon the pressure of the springs 88. This pressure can obviously be varied depending upon how far the screws or bolts 86 are screwed into the drum 2.

Referring especially to FIGS. 1 and 2, the cable 56 leaves the last track 8 at the bottom of the drum 4 and therefore passes to the underneath of the track 83 formed between the drum 2 and the pressure plate 84. The cable 56 passes up around the top of the track 83 and then starts to descend between the two

drums

2, 4. If the cable 56 is allowed to descend too far, it will contact the previously mentioned part of the cable 56 as it passes from the last track 8 at the bottom of the drum 4 to the underneath of the track 83. Therefore the cable 56 has to be prevented from doing this and it has been found convenient to pick the cable 56 from the track 83 as it begins to descend by means of a finger 94 shown most clearly in FIGS. 4 and 5.

After the cable is picked out of the track 83 by the finger 94 it is led through a joggle housing 96 which is fixed to the back plate and which is designed to gently lead the cable 56 out of its downward path where it would foul up on itself and into a clear path where it can be run out of the winch as shown in FIG. 2. The housing 96 may be in two halves which fit together to form a passageway for the cable 56. The path which the cable 56 goes through after it has been picked out of the track 83 is shown at 98 in FIGS. 1 and 5. Shown at 100 in FIG. 1 is the cable 56 in section as it enters the winch.

Since the cable 56 enters and leaves the winch vertically as can best be seen in FIG. 2, it is necessary to form the top of the casing half 66A with a slot 102 shown in phantom in FIG. 1, so that the casing does not hit the inlet part of the cable 56, and the bottom of the casing half with a shorter slot (not shown) so that the casing does not hit the outlet part of the cable 56. In the described embodiment, the cable 56 has been shown as entering the winch at 100 at a position away from the back plate I0 and leaving the winch at a position near the back plate 10. Obviously, this arrangement can be reversed so that the cable 56 enters the winch near the back plate 10 and leaves the winch away from the back plate 10. A short slot may then be used onthe top of the casing 66, a longer slot on the bottom of the casing, and the drum 4 may be inclined in the opposite direction to the direction presently shown.

The electric motor 74 is started by operation of a handle 104. When the handle 104 is raised, it makes contact with an electrical switch 106 and the motor 74 drives the worm 82 one way so that the winch can climb a suspended cable. When the handle 104 is pressed downwardly, it makes contact with an electrical switch 108 and the motor 74 drives the worm 82 the other way so that the winch can descend a suspended cable. The handle 104 is pivotable about a point 110 and in the intermediate position between the up and down positions, no switches are activated and the electric motor stays switched off. For simplicity, no electrical connections have been shown from the handle 104 and the

switches

106 and 108 to the motor 74, since these are merely standard connections and they are not necessary for an understanding of the present invention. The switches 106-108 are housed in a casing 112 which is joined to the housing 26.

As indicated above, the pressure plate 84 rotates with the drum 2 because it is fixed to the drum 2. Whilst the cable 56 is in the track 83, the springs 86 cause the cable to be gripped with a predetermined force. Thus, the cable is constantly placed under tension from within the winch by the pressure plate 84 and the pressure plate 84 only acts on that part of the cable that is within the said single cable-receiving track 83. In other words, during operation of the winch, constantly differing adjacent protions of the cable 56 will be acted upon by the winch but these portions will always be of the same length. If the cable is fixed to the top of a structure and is hanging therefrom, the pressing/rotating action of the pressure plate 84 will cause the winch to climb the cable and those portions of the cable 56 that have been acted upon by the pressure plate will merely leave the single cable-receiving track and will pass out through the winch casing. The cable can then merely hang from the winch as the winch is climbing and there is no need for bulky cable storage drums. If the cable is attached to an object to be moved and the position of the winch is fixed, the pressing/rotating action of the pressure plate will still cause the cable to be pulled through the winch, thus pulling the said object towards the winch. Again there is no need for bulky cable storage drums. Obviously the pressure plate 84 does not exert a pull on the cable which is equal to that required to directly pull the winch upwards or to directly pull an object along. Because of the friction existing between the cable and the two

drums

2, 4, the pressure plate only has to exert a relatively soft pull on the cable.

The use of t. worm and worm-wheel arrangement for driving the drum 2 effectively provides the winch with a simple, efficient and built-in safety feature. More specifically, the use of a worm and worm-wheel arrangement means that the drum 2 can only be rotated by the worm 82 rotating the worm-wheel 24 attached to the spindle 14. It is not possible for the drum 2 and the relatively fixed worm-wheel 24 to rotate and thereby drive the worm 82. Thus, the worm 82 is self-sustaining and can be rotated in a clockwise direction to cause the

drums

2, 4 to rotate in one direction when the winch is to climb a suspended cable and to cause the

drums

2, 4 to rotate in the other direction when the winch is to descend a suspended cable. The winch ascent or descent will always be controlled. If at any point during the winch ascent or descent, the electric motor 74 should fail, uncontrolled descent of the winch will be prevented because the cable 56 will not be able to rotate the

drums

2, 4 because the worm-wheel 24 will merely lock into the worm 82. Thus, the winch drive incorporates an automatic and robust safety device, thereby avoiding the cost of providing an auxiliary safety device if desired.

l claim:

1. A power driven cable winch comprising in combination: a housing; first and second rotatable drums each having a periphery provided with cable-receiving tracks including a first dual-width track, the first drum having its axis set squarely in the housing and the second drum being separated therefrom by an intermediate space and having its axis offset in the housing such that cable passing between the drums in the tracks travels in a straight line; a worm and worm wheel drive by means of which the rotatable drums are rotated from a motor; a cable tensioning means constituted by a pressure plate combined with the first of the rotatable drums to form a final cable-receiving track; a cable entering and leaving the winch through said intermediate space in directions substantially normal to the axis of the first drum, the cable entering the winch tangent to the squarely-set first drum and winding more than one complete turn thereabout in said dual-width track and then passing multiple turns between and around both drums in said tracks and finally making a last turn in said final track against said cable tensioning means, said cable tensioning means being such as to act on constantly differing adjacent portions of the cable. said portions of the cable always being of the same length; and a metal casing supported by said housing and covering said drums, the inner surfaces of the casing being located adjacent to the peripheries of both drums and shaped to press lightly against the cable as it passes therearound with sufficient pressure to maintain the cable in the tracks.

2. A winch according to claim 1 in which said pressure plate is spring biased.

3. A winch according to claim 1 including a guiding device for leading the portion of said cable departing from the first drum after the last turn through said winch housing.

Claims

1. A power driven cable winch comprising in combination: a housing; first and second rotatable drums each having a periphery provided with cable-receiving tracks including a first dual-width track, the first drum having its axis set squarely in the housing and the second drum being separated therefrom by an intermediate space and having its axis offset in the housing such that cable passing between the drums in the tracks travels in a straight line; a worm and worm wheel drive by means of which the rotatable drums are rotated from a motor; a cable tensioning means constituted by a pressure plate combined with the first of the rotatable drums to form a final cable-receiving track; a cable entering and leaving the winch through said intermediate space in directions substantially normal to the axis of the first drum, the cable entering the winch tangent to the squarely-set first drum and winding more than one complete turn thereabout in said dual-width track and then passing multiple turns between and around both drums in said tracks and finally making a last turn in said final track against said cable tensioning means, said cable tensioning means being such as to act on constantly differing adjacent portions of the cable, said portions of the cable always being of the same length; and a metal casing supported by said housing and covering said drums, the inner surfaces of the casing being located adjacent to the peripheries of both drums and shaped to press lightly against the cable as it passes therearound with sufficient pressure to maintain the cable in the tracks.

2. A winch according to claim 1 in which said pressure plate is spring biased.