US3721426A

US3721426A - Cable winch

Info

Publication number: US3721426A
Application number: US00160621A
Authority: US
Inventors: C Kaufer
Original assignee: Individual
Current assignee: Individual
Priority date: 1970-08-25
Filing date: 1971-07-08
Publication date: 1973-03-20
Anticipated expiration: 1990-03-20
Also published as: DE2041993B2; DE2041993A1; GB1316014A

Abstract

A cable winch, particularly for scaffolds, comprising a housing and a driving pulley mounted for rotation within the housing and around which pulley the cable passes. A flexible contact-pressure element attached by one end to the housing presses the cable against the driving pulley over a contact angle of more than 180*. The contact-pressure element is responsive to the load applied to the cable whereby an increase in load increases the contact-pressure applied by the element to the cable, and viceversa.

Description

[ 3,721,426 1March 20, 1973 United States Patent [54] CABLEWINCH 3,231,240 H1966 Naito.........t...l.....4.. ....4.......254/l91 76 Inventor: C Kaufer, Kupfbrberg, 3,520,515 7/1970 Pomagalskl..........l............254/l75.5

near Wipperfurth, Germany July 8,1971

Primary Examiner-Harvey C. Hornsby Att0rney-Hubert T. Mandeville et al.

[22] Filed:

ABSTRACT [21] Appl. No.: 160,621

[30] Foreign Application priority Data A cable winch, particularly for scaffolds, comprising a housing and a driving pulley mounted for rotation Aug. 25, 1970 Germany...................V.P 20 41 993.6

within the housing and around which pulley the cable passes. A flexible contact-pressure element attached by one end to the housing presses the cable against the driving pulley over a contact angle of more than 180.

0 m 7] Id 46 56 B 7 6 l 4 5 Field of Search.......................

167 The contact-pressure element is responsive to the load applied to the cable whereby an increase in load in- [56] References Clted creases the contact-pressure applied by the element to the cable, and viceversa.

UNITED STATES PATENTS 3,100,626 8/1963 Good.....................v...........254/175.5 6 Claims, 1 Drawing Figure CABLE wmcn BACKGROUND OF THE INVENTION The invention relates to a cable winch, particularly for scaffolds, having a driving pulley which isaccommodated in a housing and around which pulley the cable passes and against which it is pressed by means of a flexible and adjustable contact pressure element affixed by one end to the housing. In particular, the invention relates to a motor-operated cable winch having a driving pulley unit, for the vertical transport of passengers, for use with so-called scaffolds.

With cable winches intended for use with scaffolds it is desirable for the cable to be passed around a driving pulley in such a way that the cable cannot slip out of place in relation to the pulley. For this purpose the cable has hitherto been placed in a number of turns about the driven pulley, a method which, however, involves a number of drawbacks. In particular, the pressure of the cable against the pulley, in such a winch, cannot be varied in accordance with the load applied to the cable, and automatic retraction of the cable into the winch is likewise impracticable.

PURPOSE OF THE INVENTION which the cable can be retracted automatically.

SUMMARY OF THE INVENTION The invention proposes, for the performance of the task required, that with such a cable winch the flexible contact pressure element should embrace the driving pulley by more than I80 and vary the force of its pressure on the cable in proportion to the load applied to the cable. In a construction of this kind the cable need only be taken around the driving pulley once, not even a complete turn being required, so that the retraction of the cable into the winch can be carried out without difficulty and therefore automatically.

In a preferred construction of the invention the contact-pressure element is connected by its free end to a tensioning element whose tension is adjusted by the load applied to the cable. This tens ioning element may consist of a cable deflector roller which is mounted in an eccentrically pivotable manner at the cable inlet and which is attached, eccentrically in respect of the pivoting point, to the free end of the flexible contacbpressure element. When the load applied to the cable winch increases, the pressure of the cable placed around the deflector roller is eccentrically pivoted and pulls the flexible contact-pressure element in the process, so that the latter presses more firmly against the driving pulley and thus against the cable passing around the driving pulley. In this manner the deflector roller can also be subjected to the action of a spring tending to draw it away from the driving pulley, as a result of which a predetermined minimum contact-pressure force by the pressure element is ensured.

According to a further characteristic of the invention, a fixed cable guide system interacting with the deflector roller is affixed at the cable inlet and facilitates the passage of the cable through the winch.

This cable guide system can interact with an adjustable cable-locking device, preferably provided at the cable outlet.

The flexible contact-pressure element is preferably equipped with numerous contact-pressure rollers which, via a flexible element, preferably a chain or a cable guide system, are connected with one another and with the eccentrically pivotable contact-pressure roller. This ensures that the contact-pressure element will make contact over an ample length of the cable passing around the driving pulley, while producing comparatively little friction. The contact-pressure force is thus transmitted to' the cable in a manner largely free of loss.

For drive purposes the driving pulley has an internal system of gear teeth engaged by a drive pinion of a driving gear. The latter can be directly connected to a drive motor, which is mounted on the cable winch itself. For reasons of safety, moreover, a hand crank can be connected with the gearing, so that the winch can be operated even if the motor fails.

BRIEF DESCRIPTION OF DRAWING The drawing shows in cross-section a cable winch constructed in accordance with the teachings of the invention.

DESCRIPTION OF SPECIFIC EMBODIMENTS A cable winch comprises a housing 1 and a driving pulley 3 mounted in the housing so as to be rotatable about a central shaft 2 and having a flange-connected internally-toothed ring 4 engaged by a driving pinion 5 of a driving gear which is mounted on the rear of the housing 1 and which is therefore not shown in detail in the drawing. The driving gear can be connected with a driving motor, likewise not shown. The driving gear preferably consists of a worm gear which, to assist the self-locking action of the gear, can be provided with a brake 6. In case the driving motor should fail, a hand crank 7 can be attached to the gearing, enabling the entire cable winch and the scaffold attached to it to be let down.

The driving pulley 3 is provided on its outer periphery with a groove 8 into which a cable is pressed by a contact-pressure element 10. As may be seen from the drawing, the cable 9 only passes round the driving pulley 3 once, the inlet and the outlet of the cable being close together in the upper zone of the winch. Between the ingoing end and the outgoing end of the cable, moreover, is a fixed cable guide system 11, which likewise comprises grooves 12 and 13 for the lateral guiding of the cable 9. In the drawing, the cable inlet is on the right and the cable outlet on the left.

In the example shown the contact-pressure element 10 consists of a link chain 14 with numerous contactpressure rollers 15. The right-hand end of the link chain 14 is affixed to a fixed link pin 16 in the housing 1, while the left-hand end of the link chain 14, passing around the driving pulley 3 by more than is flexibly affixed to a bar 17 which in turn is flexibly connected to a lever 18 pivotably suspended around a fixed pin 19 in the housing 1. The lever 18 is also subject to the action of a tension spring 20 which ensures a certain minimum pressure of the contact-pressure element 10 against the cable 9 passing around the driving pulley 3.

Approximately in the center of the lever 18, a deflector pulley 21, acting against the ingoing end of the cable, is rotatably mounted in such a way that the deflector pulley can be pivoted, with the lever 18, about the pin 19 serving as an eccentric pivot. If a load, such as a scaffold, is suspended on an eyelug 22 provided at the bottom of the housing 1, then the cable will exert against the deflector pulley 21 a pressure the magnitude of which will depend on the size of the load thus applied to the cable 9, because the cable tends, under the influence of the load applied, to assume a straight position. As a result, the cable presses the deflector pulley 21 to a greater or smaller distance towards the right, in which process the deflector pull'ey 21 is pivoted about the pin 18 and thus, via the bar 17, exerts on the contact-pressure element a tractive force which will exceed that of the spring 20. This in turn causes a greater contact-pressure force to be exerted on the cable passing around the driving pulley 3, so that the former is reliably prevented from sliding over the latter. On the contrary, the cable will be firmly pressed into the groove 8 of the driving pulley, as a result of which the load attached to the eyelug 22 can only be raised or lowered when the driving pulley 3 is rotated via its drive motor.

In the vicinity of the cable outlet, a cable locking device in the form of an eccentrically mounted pawl 23, is movable into an engaged position in which it locks the cable to the cable guide 1 1.

What is claimed is:

l. A cable winch, particularly for scaffolds, comprising a cable, a housing, a driving pulley mounted for rotation within the housing and around which pulley the cable passes, said driving pulley being provided with a peripheral groove containing the cable, a flexible contact-pressure element attached by one end to the housing and pressing the cable against the driving pulley over a contact angle of more than 180, said contact-pressure element being responsive to load applied to the cable whereby an increase in load increases the contact pressure applied by the element to the cable and a decrease in load decreases the contact pressure applied by the element to the cable, said contact-pressure element being attached by one end to a first pivot on the housing and by its other end to a tensioning element responsive to the load applied to the cable, said tensioning element including a deflector pulley in rolling guiding contact with the cable and pivotable eccentrically about a second pivot located adjacent the driving pulley where the cable approaches the driving pulley, and wherein the other end of the contact-pressure element acts on the deflector pulley eccentrically with respect to the second pivot, whereby an increase in load on the cable causes the cable to pivot the deflector pulley about the second pivot in a direction away from the driving pulley, thereby increasing the contact pressure applied to the cable by the contactpressure element.

2. A cable winch as claimed in claim 1, wherein the deflector pulley is subjected to the action of a spring tending to draw the deflector pulley away from the driving pulley so as to maintain a predetermined minimum contact pressure by the contact-pressure element.

3. A cable winch as claimed in claim 1, including a cable guide means fixed in relation to the driving pulley and gutding the cable into and out of contact WI h the driving pulley in co-operation with the deflector pulley.

4. A cable winch as claimed in claim 3, further comprising a locking device co-operating with the cable guide means and operable to lock the cable to the cable guide means.

5. A cable winch as claimed in claim 1, wherein the flexible contact-pressure element has a plurality of contact-pressure rollers.

6. A cable winch as claimed in claim 1, wherein the driving pulley has internal gear teeth meshing with a driving pinion of a motor-driven driving gear.

Claims

1. A cable winch, particularly for scaffolds, comprising a cable, a housing, a driving pulley mounted for rotation within the housing and around which pulley the cable passes, said driving pulley being provided with a peripheral groove containing the cable, a flexible contact-pressure element attached by one end to the housing and pressing the cable against the driving pulley over a contact angle of more than 180*, said contactpressure element being responsive to load applied to the cable whereby an increase in load increases the contact pressure applied by the element to the cable and a decrease in load decreases the contact pressure applied by the element to the cable, said contact-pressure element being attached by one end to a first pivot on the housing and by its other end to a tensioning element responsive to the load applied to the cable, said tensioning element including a deflector pulley in rolling guiding contact with the cable and pivotable eccentrically about a second pivot located adjacent the driving pulley where the cable approaches the driving pulley, and wherein the other end of the contact-pressure element acts on the deflector pulley eccentrically with respect to the second pivot, whereby an increase in load on the cable causes the cable to pivot the deflector pulley about the second pivot in a direction away from the driving pulley, thereby increasing the contact pressure applied to the cable by the contact-pressure element.

3. A cable winch as claimed in claim 1, including a cable guide means fixed in relation to the driving pulley and guiding the cable into and out of contact with the driving pulley in co-operation with the deflector pulley.