CA1174651A - Rope sling device - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
The rope sling device is formed by a base plate, a stationary friction cylinder, an eccentrically pivoting auxiliary friction device, and another braking surface. If the person to be lowered is suspended on the base plate, the rope runs between the auxiliary friction device and the other braking surface, it is also diverted at the auxiliary friction device by ca. 180°, it runs around the stationary friction cylinder with 2-1/2 windings, and leaves the rope sling device upward. In lowering, the person to be lowered is slowed down because of the fact that a frictional force occurs at the stationary friction cylinder. A frictional force is also formed when the rope runs over the auxiliary fric-tion device. If the lever 64 is left alone, then the auxiliary friction device connected to it is pivoted by the frictional force of the rope sliding over it so that is presses the rope against the other braking surface, until the rope comes to a stop because of the automatic clamping. The person to be lowered, however, can turn the lever, which is connected to the auxiliary friction device through the gear so that it unlocks or loosens the automatic clamping and no braking occurs on the brake surface.
The stop is then released and the rope sling device moves down-ward on the rope.

Description

-- ~174~51 .

This invention concerns a rope sling device for lowering a pers~n or load on a rope, in which the rope passes around a fri.ction cylinder firmly attached to a base plate.

Such rope sling devices are known; for example, see US Patent 362,173, 2,691,478, 2,432,741, 848,235, 1,351,734, German Patent 115,414, German Patent Disclosure 2,739,637,~ Swiss Patent 39,893. ~ seat belt in which a person to. be lowered sits, or a load, can.be suspended from the base plate.
Under the weight of the person, the rope sling device then slides downward on the rope. The braking of the rope sling device is accomplished by the force of friction which is formed in the sliding of the rope around the fixed friction cylinder. In addition to the friction force which is produced on the fixed friction cylinder, other surfaces are also pro-vided under some circumstances on which the rope slides and can therefore .be braked (cf. in US Patent 362,173, the guide ring (D) and the friction cylinder (E)).

In these known rope sling devices, the speed can be regulated by the person who is. being lowered on the rope sling device grasplng the rope and thus slowing it down, or by exerting another braking force on the rope through a lever. If this is not the case, i.e.,.if the person to be lowered does not :

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parti~ipate actively himself in the lowering process in the sense of increasing the 'braking force, the rope sling device' moves downward with a speed det'ermined only by the braking force on the friction cylinder.

However, there'are working situations in which it is desired that the rope sling device'should stop on the'rope when the person does not intervene. For example, this is the case in working situations where a person wishes and should work with two free hands at a certain height, perhaps on a'facade, while he himself starts and controls the process of the downward motion by acting on the braking devices on the rope sling device. In other words: in the case of complete inaction of the person to be lowered, the device should stop.

Such a'requirement can also arise in a hazardous situation to prevent a person moving downward on the rope at an uncontrolled' high speed, when he can no longer slow the speed of the rope sling device, for example, because he has become unconscious.
This would lead to injuries upon striking the ground. Those rope sling devices which, in contrast to the aforementioned rope sling devices, do not operate with a fixed friction cylinder but instead with a friction cylinder rotating freely in the one direction of rotation and locking in the other direction of rotation, have this drawback (see for example, US Patent 3,759,346 and 3,807,696).

., ~ 17~6~ 1 It is therefore :the purpose of this invention to improve the rope sling device of the type mentioned initially, so that on the one hand the regulation of the braking speed is very easily possible, but that on the other hand, in the absence of any action by the person to be lowered or. by a helper, an absolutely safe braking is guaranteed until the rope sling device has come to a.stop. It is also intended to be guaranteed that there can be no.tangles or sllppage, and no climbing of coils onto neighboring coils. The rope must also have the simplest possible ~structure.

This problem is solved pursuant to the invention by providing that the rope - in addition to. being guided on the fixed friction cylinder - also passes around a pivoting auxiliary friction devioe connected to a lever, which is rotated by the friction of the rope passing around it so that it presses the rope against another brak;ng surface.

Alternatively, a solution of the problem presented is produced if the rope, in addition to being guided around the friction cylinder, also passes around a pivoting auxiliary friction device connected to a lever, on which a spring exerts a force so that it pr~ses the rope against another.braking surface.

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It is therefore common to both solutions of the problem pre-sented that another auxiliary friction device is provided which -` ~17~6~1 presses the rope so strongly against another braking surface in the normal state that a complete slowing to a stop occurs.
In the first~mentioned solution, this is guaranteed by the fact that the auxiliary friction device is mounted so that it is rotated or pivoted Sy the force of friction of the rope passing around it and thus presses the rope against the braking surface. An automatic clamping or locking therefore occurs, which is brought about by the fact that in the downward slide of the rope sling device on the-rope, the pressure of the auxiliary friction device against the other braking surface constantly increases until the motion stops. In the solution mentioned in the second place, the same effect is produced ky a spring. In both cases, the person to be lowered (or a helper) can now grasp a lever with which the auxiliary friction cylinder is connected, and move it in the opposite direction, or in the direction against the automatic clamping in the first solution and in the.direction against the force of the spring in the second solution. If this is the case, the frictional force on the rope becomes smaller and the rope sling device can move downward. In the case of complete inaction of the person to be lowered, for example, if he wishes to have both hands free and wishes to work at a certain posi-tion (when used as a labor device), or in the case of loss of consciousness or injury ~when used as a rescue device), however, an increase of the rate of drop is absolutely precluded.
Instead, braking occurs to a full stop. When used as a rescue '` ~174~51 device, the person must then be rescued in another manner.

Such a rope sling device is quite particularly suitable for a one-time 'descent on a rope for equipping rooms in the upper stories of hotels which can no longer' be reached by ordinary rescue'devices tladders, etc.).

The critical difference from the known rope sling devices mentioned at the outset consists of the fact that the action of the auxiliary friction device'is slackened, i.e., reduced by the action of the person to be lowered.

The first-mentioned of the two solutions, which operates with the automatic clamping of the auxiliary friction device,' which is caused by the friction of the rope passing around it, , i5 preferred when it is important to avoid a spring whose break-a'ae could be a hazard, for reasons of maximum reIiability and strong stresses from rough handling. Finally with this solution, a particularly sensitive speed control is obtained.

A particularly important beneficial improvement of the inventio~
provides that the base plate with two side plates located on it forms a chamber accessible from the'front in which are located the friction cylinder, the auxiliary friction device, and the : ;

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other braking surface, and that a cover is provided by which this space can be sealed off. In such a form of the housing, formed by a chamber which can be covered, the rope on the one hand is guided with complete security, while on the other hand it can be taken out easily.
Therefore, the rope sling device can be used in repeated succession, since the rope can be easily taken out and again replaced in a new starting position. It is not necessary to put up with any ha~ards at all in the ready condition, because of this simple resetting capability.
In this design, both the friction cylinder and the auxiliary friction device can be designed without flanges, i.e., without special rope guide elements, which leads to another simplification of handling and of the engineering construction.
In one aspect of the present invention there is provided a rope sling device for lowering a person or a load, the device comprising a continuous length of rope;
a housing having a base plate; a nonrotatable friction cylinder secured to the base plate, one portion of the rope being wrapped at least once around the friction cylinder; a cam secured to the base plate and being rotatable about an axis eccentric with respect to the center of the cam, the cam having exterior camming surface, a stationary braking surface, another portion of the rope passing between the exterior camming surfaces and the braking surface, rotation of the cam in a first direction urging the another portion rope against the braking surface to tightly capture the another portion of the rope between the exterior camming surfaces and the braking surface to prevent further movement of the rope;
and a manually actuated lever for rotating the cam in a second direction opposite of the first direction to move the exterior camming surfaces away from the braking surface to allow further movement of the rope, the lever having a handle portion to allow manual gripping thereof.

~ ~ 7~ 5 1 -6a-In a further aspect of the present invention there is provided a rope sling device for lowering a person or a load, the device comprising a continuous length of rope, a housing having a base plate; a friction cylinder nonrotatably mounted to the base plate, a portion of the rope passing at least once around the outer surfaces of the friction cylinder;
a cam secured to the base plate and being rotatable about an axis eccentric with respect to the center of the cam, another portion of the rope passing around at least a portion of the outer camming surface surfaces of the cam; a stationary braking surface having a curved configuration and being in spaced, confronting relation with the outer camming surfaces; a manually actuated lever extending from the housing and being rotatably mounted with re~pect to the base plate, the lever having an exterior handle portion to allow manual gripping thereof;
and gear means coupling the lever to the cam for rotation of the cam in a first direction when the handle portion of the lever is manually raised to increase the spacing between the outer camming surfaces and the braking surface to allow movement of the rope therebetween, friction between the outer camming surfaces and the rope causing the cam to rotate in a second direction opposite of the first direction to drive the outer camming surfaces toward the braking surface when the handle portion of the lever is not being manually raised to capture another portion of the rope between the camming surfaces and the braking surface for preventing further movement f the rope-In a further aspect of the present inventionthere is provided a rope sling device for lowering a person or a load, the device comprising a continuous length of : rope; a housing having a base plate; a friction cylinder nonrotatably mounted to the base plate, a portion of the rope passing at least once around the outer surfaces of ~ ' i ,~

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~ 5 -6b-the friction cylinder; a generally planar stationary braking surface facing away from the friction cylinder;
a rod nonrotatably mounted to the base plate adjacent the braking surface in generally parallel alignment with the friction cylinder, the rod being spaced from the friction cylinder, another portion of the rope passing around the rod to form a loop having an arc of approximately 180 : a cam mounted to the base plate and being rotatable about an axis eccentric with respect to its center, the cam having outer camming surfaces formed thereon, in spaced, confronting relation with the braking surface, a third portion of the rope passing between the braking surface and the outer camming surfaces spring means for biasing the cam in a first direction of rotation to move the outer camming surfaces toward the braking surface to capture the third portion of the rope between the braking surface and the outer camming surfaces to prevent further movement of the rope; and a manually rotatable lever rigidly attached to the cam for manual rotation of the cam in a second direction opposite of the first direction to move the outer camming surfaces away from the braking surface to allow further movement of the rope, the lever having an exteriorly extending handle portion for manual gripping of the lever.
Examples of embodiment of the invention are described in detail below with reference to the attached drawings. The drawings show:
Fig. l A first embodiment represented with the cover o~en;
Fig. la An illustration of the use of the embodiment without action by the person to be lowered;
Fig. 2 A section along the line II-II in Fig. l;

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Fig. 3 A section along the line III-III in Fig. l;
, Fig. 4 A section along the line IV-IV in Fig. 2;

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Fig. 5 The example of embodiment pursuant to Fig. 1 with closed cover, or in the state ready for operation;

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Fig. 6 A modification of the embodiment of Fig. l;

- Fig. 6a An illustration of the use of the modified embodiment pursuant to Fig. 6;

Fig. 7 A second example of embodiment, in which a section of the stationary friction cylinder and of the ~ .
auxiliary friction device are broken away;

Fig. 8 A top view of the embodiment pursuant to Fig. 7, but without individual components broken away;

Fig. 9 A partial cross section through the embodiment pursuant to Fig. 7 or 8;

Fig. 10 A section along the line X-X in Fig. 7 or 9;

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Fig. 11 A third example of embodiment Fig. 12' A view in the direction of *he arrow XII-XII in Fig. 11;

Fig. 13 A view in the direction of the arrow XIII-XIII in Fig. 11; , Fig. 14 A section along the line XIV-XIV in Fig. 11.

The rope sling device pursuant to the first example of embodi- .
ment has a base plate 1 on which is located a stationary -friction cylinder 2. As seen from Fig. 2 and Fig. 3, a chamber-like housing open towards the front is formed because ~ .1 . .... .
of the fact that ~wo side plates 71 and'72 are firmly connected to the base plate i. This chamber is closed by a cover 73 with a U-shaped cross section (see Fig: 1 ) which is linked to the side plate 71 by screws 74 and 75. Fig. 1 shows the rope sling device with open cover 73. In Fig. 5, the'cover is closed, and with the use of a helical screw 76 screwed into the threaded hole 77-tFig. 1) in the side section 72, is fixed in this closed position. As seen in Fig. 2, the upper cover section 78 ~which corresp~nds in cross section to the upper leg of the U in Fig. 1) has a first slot 79. Similarly, the lower cover section 80 (which corresponds to the bottom leg of the U in the cross section) has a second slot 81. When the 17~5~ -g chamber is closed, or in .the position shown in Fig..5,.the rope'6 passes through the'two slots. Still ano.ther guide pin 82 is located on the'base plate 1. 'The rope guide.'block 14 also .ser.ves to secure'the rope 6. when turning ~round the stationary friction cylinder 2. The. base plate 1 has an opening 34 in which a person who is to be lowered is sus-pended by means of a snap hook and eye 35 and a seat belt 36.
The weight of the person then acts on the base plate 1 in the'direction of the arrow 3.8 in the drawing.

~ An auxiliary friction device 84 is also located on the. base plate 1 with the help of a bolt 83. The auxiliary friction device 84 can swivel around the bolt 83, which is screwed .~ ~ , into the base plate l. 'The bolt 83 fits into an appropriate . '' hole in the auxiliary friction device 84. This hole is , located eccentircally in the auxiliary friction device 84.
As seen from Fig. 4, a ge,ar 85 is firmly joined to the auxiliary friction device 84. The axis of rotation of this gear is displaced with respect to the auxiliary friction device 84, so that upon the rotation of the auxiliary friction device 84 around the bolt 83, it rotates not eccentrically, but normally concentrically. The gear B5 is engaged with a second gear 86 which is connected firmly to the lever 64,' which is mounted to rotate by the use of a pin 87 in the side section 72.and which extends outward through an opening 88 in the side section 72.

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( -" 1 17~65 1 As als~ seen from Fig. 4, the cross section of the upper region of the side section 72 is designed so that it produces a curved braking surface 89. As seen from Fig. 1, the rope 6 runs through between the auxiliary friction device 84 and the braking surface 89.

As also seen from Fig. la, the upper end 6' of the rope 6 is fixed at any position from which a person decides to descend. The rope runs from there into the rope sling device and one and one-half times around the stationary friction cylinder 2. The rope then passes around the auxiliary fric-tion device 84 and thus also between the auxiliary friction device 84 and the braking surface 89. From there, it runs downward.

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If a person is now lowered with the use of this rope sling device, the rope 6 slides from below in the direction of the arrow 39 into the descending rope sling device, and over the auxiliary friction device 84 and over the friction cylinder 2.
It therefore runs counterclockwise around the auxiliary fric-tion device 84 with an arc of contact of ca. 180. It then runs to the friction cylinder 2. It runs one and one-half times around the friction cylinder 2, and from it again upwards, out of the rope sling device. The rope 6 is primarily braked .
by the fact that in running around the stationary friction cylinder 2, a braking occurs because of friction. This braking force however, is not of such magnitude that with a o ~ ' l 1-~'7~

person of normal weight, a complete braking results until the device stops. Instead, a normal speed of .descent re,sults. because of the braking on the stationary friction ' cylinder 2 alone.

The remaining braking is obtained by the use of'the auxiliary friction device'84 and the braking surface 89, ,in the follow-ing way: . ~

(a) The person who is lowering himself with the rope sling device, does not to~ch the lever 64 The rope runs from bottom to top through the device in the .... , ~ .
direction of the arrow 39 in the drawing. Because of the frictional force between the rope 6 and the auxiliary friction device 84, the auxiliary friction device 84 is rotated counterclockwise around the. bolt 83. Since this is an eccentric motion around the bolt 83, the rope 6 is pressed by the auxiliary friction device 84 against the braking surface 89. The rope 6 is thus clamped with automatic slowing and self-retention between the auxiliary friction device 84 and the braking surface'89. If the rope 6 still slides over the.auxiliary friction device 84 anyhow, it has the tendency to intensify the force with which the auxiliary friction device 84 presses the rope 6'against the braking surface 89. This ' ' . .

~ ~ 7~5 1 applies a braking force which constantly leads reliably to the stopping of the rope sling device on the rope 6.

b) The person who is lowering himself with the rope sling device presses the lever 64 upward:

The gear 86 then rotates counterclockwise,and the gear 85 rotates clockwise. For this reason, the auxiliary friction device 84, which is connected firmly to the gear 85, also rotates clockwise and thus in a dixection in which the distance between the auxiliary friction device 84 and the braking sur-face 89 is increased. The automatically intensifying and self-retaining clamping action between the auxiliary friction device 84 and the braking surface 89, mentioned above, is eliminated. The entire braking force is not so strong that it leads to a complete stoppage. Instead, as previously describéd, sliding occurs at a speed which depends upon the size of the radii of the friction cylinder 2 and the auxiliary friction device 84, as well as on the corresponding arc of wrap and the weight of the rope sling device plus the person to be lowered.

Fig. 6 shows a modified form of embodiment. The rope 6 in this case is guided twice around the stationary friction cylinder 2 and downward out of the rope sling device. The upper cover ' 117~51 section 78' accordingly no longer has an opening, while an appropriate larger' opening 81' is prov'ided in the'lower cover section 80. A bracket 101, which has an opening 102, i8 welded to the top of the base plate 1.

The method of use of this modified embodiment is illustrated in Fig. 6a. The 'lowering process occurs through a helper H, who operates the lever 64 of the rope sling device, which is designated in Fig. 6a with an A. The rope sling device A is fastened to a frame 103 with the help of the opening'102.
This frame stands on a surface 104 fixed in location. The rope sling device is therefore suspended at a fixed point~
The person P to be lowered is suspended with the seat belt 36 at the lower end 6' of the rope 6 running down out of the rope sling device.

Therefore, this is not the case as in the embodiment pursuant to Fig. 1, wherein the person to be lowered "moves down on the rope"; instead, the position of the rope sling device remains fixed. If the end 6" on which the person to be lowered is fastened is considered as the forward end, the rope runs from top to bottom through the rope sling device.

In repeating the lowering process, in the example of embodiment pursuant to Fig. 1 or Fig. la, the following is true: after completion of the lowering process, i.e., when the person P

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has climbed out of the seat belt 36, the rope 6 with the rope'sling device suspended from its bottom end is simply hoisted up again. The cover 73 is then opened, the rope is taken out, and again placed in so that it is located in the vicinity of the upper end 6'. Another person can then be lowered.

In the modified embodiment pursuant to Fig. 6 or the use pursuant to Fig. 6a, the cover 73 is first opened, the rope is then taken' out, and the end 6n -is hoisted up. The rope' ' is then placed in again so that the rope sling device'is then ready for another lowering process.

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In the example of embodiment pursuant to Fig. 7, the friction cylinder 2 i5 also fastened to the base plate 1 with bolts 5.
The friction cylinder 2 has flanges 3 and 4. The guide rings 37 and 37' are used as rope guides. A rope guide block 114 is provided above the friction cylinder 2, which surrounds the coils of the rope 6 on the friction cylinder 2 like a chamber.

When the rope 6 moves towards the rope sling device in the direction of the arrow 39, it runs past the plate 52 and with a deflection of ca. 180 around the cylindrical rod 53 welded to the plate 2. The side of the plate 52 forms the braking surface 54. The rope 6 runs along this. The braking surface 55, formed from a section of the'outer surface of the cylindrical ~ 1 17~5 1 rod 53, follows this. The rope runs 1-1/2 tLmes around the friction cylinder ~ and then leaves it through the guide ring 37. The left side of the plate 52 in Fig. 7 has a 'rounded shape and'covers the space between the two flanges

2 and 3 and thus forms another' chamber-like guide for the rope.

As is apparent from Fig. 10, a plate 56 is connected at right angles to plate 52. It forms an integral component with plate'52 and rod 53 (the plate 56 in Fig. ~ lies in front of the plane of the illustration and is broken away there).
Between the plate'56 and the base plate 1 is located a rotatable shaft 57. It constitutes the auxiliary friction device. The rotatable arrangement is obtained from the journals 58 and 59 of the shaft 57 extendin~ into holes 6~ and 61 in the plate 56 and the base plate 1, respectively. As seen in ~ig. 7, the cross section of the shaft 57 in the region 62 has an eccentric design, so that an eccentric outer surface 63 results in this region. This outer surface is recessed into the shaft 57, so that a guide for the rope 6 is formed at the same time. The shaft 57 is connected to the lever 64, with which the rotational position of the shaft 57 can be changed. Depending on the position of the lever 54 or of the , shaft 57, the rope in passing between the outer surface 63 of the shaft 57 and the braking surface 54 is pressed with varying strength against the braking surface 54. In the same '` 117~51 way, the friction which occurs in the passage of the rope 6 between the braking surface 54 and the rope 6 and also between the outer surface 63'and the rope 6 is of varying strength. On the other hand, in the position 64l drawn in Fig. 1 with broken lines, there 'is no braking. The rope' 6 then passes freely through.

The shaft 57 is provided with an annular groove on~the'right side in Fig. 4. A torsion spring is loGated in this, one' end of which extends into an opening in the base plate 1, and the other end into an opening in the shaft 57, and is pre-stressed so that it presses the lever 64 in the direction of the arrow 28. Thé effect described above is thereby produced, namely the outer surface 63 of the shaft 57 is pres'sed against the rope 6, if the lever 64 is not pushed upward by the person to be lowered.

In the third example of embodiment, the friction cylinder 2 is a'lso located firmly on the base plate 1. The rope is also wound with 1-1/2 windings around the frictional cylinder 2, It runs on the friction cylinder 2 over the bottom crossbar of an oval guide bar 7, which is connected with a brace 9 which is bolted fast to the base plate 1. The oval guide bar (cf. Fig. 2) is formed by the 'two longitudinal bars 10 and 11, the'lower crossbar 8, and the upper crossbar 12. The bars 8, . . .
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10, 11, and 12 define a guide opening 13 through which the rope 6 passes. ' The lever 18 is linked with capability of pivoting to the top of the rope'guide block 14. It consists of a flat steel bar 19 and a pipe sectiQn 20 welded to it. A pulley 21 is welded fast to the upper end of the'flat iron bar 19 (cf.
Fig. 5). A hole 22' extends through the upper end-of the flat iron bar 19 and the pulley 21, through which 'is passed a bolt 22 which is bolted fast to the rope guide block 14.
The bolt connection is secured by another bolt 23 which acts on a smoothly turned cylindrical section 24 of,the bolt 23.
The lever 18 can therefore pivot around the bolt 22.

The auxiliary friction device 25 is firmly attached to the' brake handle 18 (cf. Fig. 12). Its location on the brake handle'18 (cf. Fig. 1) is such that the rope 6, before it is diverted by ca. 180 at the lower crossbar 8 of the guide frame 7, passes through between the friction cylinder 2 and the auxiliary friction device 25. It is thereby pressed by the braking surface 25' of the auxiliary friction device 25 against the surface of the windings of the rope 6, which lie on the frictio,n cylinder 2. This surface area of the windings forms the other' braking surface 25"'. The auxiliary friction device 25 is provided with a flange 26 which pre-vents the rope 6 from sliding laterally off in case of .

~ 17as65 1 careless handling, A tension spring 27 is provided between the friction cylinder 2 and the lever 18, which pulls the lever 18 in ~he direction of the arrow 28. Its other end is fastened to the friction cylinder 2 by the use of the swivel plate 30 and the bolt 29;
at its other end, it is fastened to the lever 18 by the use of the swivel plate 31 and the bolt 32.

A rod 33 is welded to the upper end of the oval guide frame 7, which represents a stop for.the lever 18 in the direction opposite to the'arrow 28.

A guide ring 37 is attached to the 'top of the base plate 1 to secure the,rope 6.

~The rope 6 covers'the fo~lowing path in the lowering of the rope sling device (cf. Fig. 1). It runs from below up to the rope sling device (arrow 39 in Fig. 1). It then runs between the braking surface 25" (the coils of the rope 6 around the friction cylinder 2) and the braking surface 25' on the auxiliary friction device 25. It then runs to the crossbar 8 of the guide frame 7 and is diverted by it by ca. 180. The section of the surface of the crossbar 8 over which the rope 6 runs is designated by 8' and also acts as a . - ' . ' - 117~;i51 braking surface. After the 180 diversion, the rope 6 runs up to the stationary friction cylinder 2 and passes around it 1-1/2 times or 2-1/2 times. It then runs upward through the guide ring 37.

The rope is slowed by frictional force (a) on the surface of the frictional cylinder 2, (b) on the braking surface 8' of the crossbar 8, (c) on the braking surface 25' of the auxiliary friction device 25' of the auxiliary friction device 25, and at the braking surface 25".

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The braking force pursuant to (c) can be varied by the person sitting in the seat belt 36 pushing the lever 18 opposite to the direction of the arrow 28. On the other hand, i the person to be lowered leaves the lever 18 completely alone, the force exerted by the braking surface 25' on the rope 6 is determined only by the f,orce of the tension spring 27. This is chosen to be at least so strong that when the brake handle 18 is left alone, the rate of fall is so slow that there is no risk to the person. It can also be so strongly adjusted that the person comes completely to a standstill.

Claims (12)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:-

1. A rope sling device for lowering a person or a load, said device comprising:
a continuous length of rope;
a housing having a base plate;
a nonrotatable friction cylinder secured to said base plate, one portion of said rope being wrapped at least once around said friction cylinder;
a cam secured to said base plate and being rotatable about an axis eccentric with respect to the center of said cam, said cam having exterior camming surface;
a stationary braking surface, another portion of said rope passing between said exterior camming surfaces and said braking surface, rotation of said cam in a first direction urging said another portion rope against said braking surface to tightly capture said another portion of said rope between said exterior camming surfaces and said braking surface to prevent further movement of said rope; and a manually actuated lever for rotating said cam in a second direction opposite of said first direction to move said exterior camming surfaces away from said braking surface to allow further movement of said rope, said lever having a handle portion to allow manual gripping thereof.

2. A device as recited in claim 1 further compris-ing gears for coupling said lever to said cam.

3. A device as recited in claim 1 wherein said braking surface has a generally curved configuration which conforms generally to the shape of said exterior camming surfaces.

4. A device as recited in claim 1 wherein said housing further comprises:
two spaced end plates mounted to said base plate, said friction cylinder, said braking surface and said cam being contained with a chamber formed by said base plate and said end plates, said chamber being accessible from a side opposite of said base plate; and a removable cover secured to said housing on said side opposite of said base plate, said cover sealing said chamber.

5. A device as recited in claim 1 wherein said another portion of said rope forms a loop over said exterior camming surfaces having an arc of approximately 180°.

6. A device as recited in claim 1 further comprising spring means for biasing said cam in said first direction of rotation to urge said exterior camming surfaces against said braking surface.

7. A device as recited in claim 6 wherein said spring means comprises a torsion spring.

8. A device as recited in claim 7 further comprising a rod disposed adjacent said braking surface, said rope passing over said rod to form a loop having an arc of approximately 180°.

9. A device as recited in claim 7 wherein said exterior camming surfaces are recessed on said cam and wherein sidewalls are disposed adjacent said exterior camming surfaces for providing a guide for said rope.

10. A device as recited in claim 1 wherein said lever is rigidly secured to said cam.

11. A rope sling device for lowering a person or a load, said device comprising:
a continuous length of rope;
a housing having a base plate;
a friction cylinder nonrotatably mounted to said base plate, a portion of said rope passing at least once around the outer surfaces of said friction cylinder;
a cam secured to said base plate and being rotatable about an axis eccentric with respect to the center of said cam, another portion of said rope passing around at least a portion of the outer camming surfaces of said cam;
a stationary braking surface having a curved configuration and being in spaced, confronting relation with said outer camming surfaces;
a manually actuated lever extending from said housing and being rotatably mounted with said respect to said base plate, said lever having an exterior handle portion to allow manual gripping thereof; and gear means coupling said lever to said cam for rotation of said cam in a first direction when said handle portion of said lever is manually raised to increase the spacing between said outer camming surfaces and said braking surface to allow movement of said rope therebetween, friction between said outer camming surfaces and said rope causing said cam to rotate in a second direction opposite of said first direction to drive said outer camming surfaces toward said braking surface when said handle portion of said lever is not being manually raised to capture another portion of said rope between said camming surfaces and said braking surface for preventing further movement of said rope.

12. A rope sling device for lowering a person or a load, said device comprising:
a continuous length of rope;
a housing having a base plate;
a friction cylinder nonrotatably mounted to said base plate, a portion of said rope passing at least once around the outer surfaces of said friction cylinder, a generally planar stationary braking surface facing away from said friction cylinder;
a rod nonrotatably mounted to said base plate adjacent said braking surface in generally parallel alignment with said friction cylinder, said rod being spaced from said friction cylinder, another portion of said rope passing around said rod to form a loop having an arc of approximately 180°;
a cam mounted to said base plate and being rotatable about an axis eccentric with respect to its center, said cam having outer camming surfaces formed thereon, in spaced, confronting relation with said braking surface, a third portion of said rope passing between said braking surface and said outer camming surfaces;
spring means for biasing said cam in a first direction of rotation to move said outer camming surfaces toward said braking surface to capture said third portion of said rope between said braking surface and said outer camming surfaces to prevent further movement of said rope; and a manually rotatable lever rigidly attached to said cam for manual rotation of said cam in a second direction opposite of said first direction to move said outer camm-ing surfaces away from said braking surface to allow further movement of said rope, said lever having an exteriorly extending handle portion for manual gripping of said lever.