US3586125A

US3586125A - Scaffolding winch with motor

Info

Publication number: US3586125A
Application number: US22220A
Authority: US
Inventors: Marcel Durand
Original assignee: Individual
Current assignee: Individual
Priority date: 1969-04-23
Filing date: 1970-03-24
Publication date: 1971-06-22
Anticipated expiration: 1988-06-22
Also published as: GB1279173A; FR2036970A1; FR2036970B1; DE2019701A1

Abstract

A scaffolding motor winch with a safety device to prevent a falling of the scaffolding platform. The safety device control means are coupled to the motor control means for lowering the platform to lock or unlock the safety device only when the motor is stopped.

Description

United States Patent Marcel Durand Grenoble, France 22,220

Mar; 24, 1970 June 22, 1971 Jun Polnagalski S.A. Famine, France Apr. 23, 1969 France Inventor Appl. No. Filed Patented Assignee Priority SCAFFOLDING WINCH WITH MOTOR 7 Claims, 5 Drawing Figs.

US. Cl. 182/112, 182/142 Int. Cl. E04g 3/10 50 Field of Search 182/112, 141,142,143,147

[56] References Cited UNITED STATES PATENTS 2,662,734 12/ 1 953 Allenbaugh 182/1 12 2,939,550 6/1960 Puttre 182/112 3,021,918 2/1962 Medawar.... 182/112 3,386,530 6/1968 Thompson 182/112 Primary ExaminerReinaldo P. Machado ArtorneyStevens, Davis, Miller & Mosher ABSTRACT: A scaffolding motor winch with a safety device to prevent a falling of the scaffolding platform. The safety device control means are coupled to the motor control means for lowering the platform to lock or unlock the safety device only when the motor is stopped.

SHEET 1 OF 3 PATENTEU JUN22 I971 PATENTED M22197! SHEET 2 OF 3 PIE 2 SCAFFOLDING WINCH WITH MOTOR The invention relates to an apparatus for the raising and lowering of a gangway or a scaffolding platform, comprising at least a winch secured to the platform and operated by a motor and locking means capable of gripping a safety cable, to stop the descent and hold the said platform.

An object of the present invention is to provide a winch apparatus having perfect safety in operation and excluding any possibility of a false maneuver.

According to the invention the lowering procedure is obligatorily preceded by the unlocking of the safety device, in such manner as to prevent the latter, on entering into action, from wedging on the cable and holding the platform. In the latter case the safety device would carry the load while the support cable slackens and the operator must initiate a lifting maneuver, this taking the load off the safety device, before he is able to unlock it.

According to the invention the unlocking control means are coupled to the motor control means for lowering the platform so as the safety system is actioned to lock or unlock only when the motor is stopped and cannot therefore intervene and lock during normal operation.

The safety device control may be coupled in an analogous manner to the. control used for lifting, but according to a development of the invention the said locking means include a brake device with shoes capable of gripping the said cable and so arranged as to induce a self-gripping of the brake in the downwards direction and automatic release in the upward direction.

The motorized drive shows a great advantage in that it does not need an operator for each winch on the platform, and it would be tiresome to have to use several operators just to operate the motors. According to the invention a central control for lowering operates from a distance the control means of the locking means of the various winches which action on reaching their limits of travel the motor control means of the associated winches.

Other advantages and objects will become more readily apparent from the following description of an embodiment of the invention represented in the annexed drawings in which:

FIG. 1 represents diagrammatically a scaffolding platform equipped with a safety device according to the invention;

FIG. 2 is a view in elevation, on an enlarged scale, of a winch and the associated means of locking according to FIG.

FIG. 3 shows in section and in plan the means of locking;

FIG. 4 is a view in elevation illustrating the means of locking and the motor of the winch;

FIG. 5 is a view analogous with that of H6. 4 of a variant in design.

On the drawings a scaffolding platform is supported by two

lifting winches

12 and 14, each acting in conjunction with a support cable 16 respectively 18.

Winches

12, 14 are advantageously of the type using a grooved pulley which are the object of French Pat. No. 1,531,386, and for reasons of clarity of the disclosure, only one of them, winch 12 will be summarily described hereafter.

Cable 16 is lodged in the V-shaped groove of a hauling pulley 20 which it embraces over part of its circumference. A compression wheel 22, fitted on an articulated lever 24, presses cable 16 into the groove of pulley 20 under pressure derived from the tractive stress exerted on cable 16 by a wheel 26 carried by lever 24 and engaging cable 16. The hauling pulley 20 is driven in rotation, through the intermediary of a worm-drive reducer (not shown), by a motor 28, electric for instance, which may operate in two directions. A contactor 30 with

pushbuttons

32 and 34 for starting motor 28 in one direction or the other controls the rotation movement of hauling pulley 20 either in the direction in which platform 10 is raised, or in the direction in which it is lowered (see FIG. 4). With each winch, 12 and 14 is associated a safety system 36 respectively 38 each of which acts on a safety cable or rod 40 which extends over the whole lifting height and is kept taut, by a weight 44, for example. The

safety systems

36 and 38 are mounted on the side plate of the winch 12 respectively 14. The

safety system

36 or 38, one of which only will be described, the other being identical, has two

jaws

46, 48, between which is inserted cable 40 which can be wedged by the clamping

ofjaws

46, 48. Jaw 46, in the form of a U enclosing cable 40 and jaw 48, are articulated at 52 and 52' on two

locking rods

50 and 50, the opposite end of each rod being fitted so as to pivot on a fixed axle 54 respectively 54' on the frame of winch 12. The ends of the

locking rods

50 and 50 articulated respectively at 52 and 52 are in the form of a cam or an eccentric 56 and 56' coacting with jaw 48 in such a manner that a limited movement upwards of

jaws

46, 48 in the direction of arrow F on the drawings results in a limited pivoting of rods 50 and 50' in the trigonometric direction (arrow F,) and therefor in a closing of

jaws

46, 48. A movement downwards in the opposite direction provokes the opening of

jaws

46, 48. A spring 58 permanently exerts an upward pressure on

jaws

46, 48 which are consequently applied against cable 40. It is easily understood that the slightest relative movement of cable 40 in the direction of arrow F in relation to frame 12 tends to draw

jaws

46, 48 upwards by friction and thus to close them together so that they lock on cable 40.

Rod 50 is rigidly connected to an operating lever 60 which may rotate on axle 54. By a rotation movement of lever 60 in the direction opposed to that of arrow F shown on the drawings, and against the pressure exerted by spring 58, the opening of

jaws

46, 48 is brought about by the pivoting of rods 50, 50' in the manner described above. At the end of its travel while opening the jaws the end of lever 60 butts against pushbutton 34 which is pushed in and starts the motor in the direction in which the platform 10 is lowered. inversely, when lever 60 is released button 34 is freed, motor 28 is stopped and spring 58 brings the locking system into its normal position in which the

jaws

46, 48, are applied to cable 40. Timing of the return of lever 60 may introduced by means of some device (not shown) so as to permit the complete stopping of the motor before the closing of

jaws

46, 48.

The functioning of the device according to the invention is obvious:

To raise the platform 10 pressure is applied to buttons 32 controlling the lifting by

winches

12 and 14, which by the rotation of the hauling pulleys hoist themselves up along the

support cables

16 and 18.

Locking systems

36, 38 open automatically by virtue of the relative movement of axles 54, 54' in relation to

cables

40, 42 and in no way impede the ascent. When motors 28 are stopped by releasing buttons 32, spring 58 closes once

more jaws

46, 48 to prevent a falling of the platform.

The lowering of platform 10 is effected by the actioning of levers 60 of

winches

12 and 14 which in a first phase of the pivoting movement in a clockwise direction

open jaws

46, 48 so as to

free cables

40, 42 and in a final phase action pushbuttons 34 controlling the motors 28 for the descent. On releasing levers 60 buttons 34 are freed and stop motors 28 and in a second phase, preferably timed, spring 58 closes once

more locking jaws

46, 48. it is easily seen that any false move is impossible, as the sequences of control must necessarily be respected. On the other hand a falling of the load is always prevented by the safety device.

The use of a plurality of winches 12 on the same platform 10 implies the simultaneous operation of spaced devices, and thus the presence of several operators. FIG. 5 shows an embodiment according to the invention permitting remote control from a single post 62 located for example in the center of the platform 10 (see FIG. 1). Pushbuttons 32 for movement upwards operate directly winches 12 and 14 while lowering buttons 64 excite electromagnets 66 with plunger pistons 68 associated with each

winch

12, 14 which action the various operating levers 60. When plunger 68 reaches its limit of travel and

jaws

46, 48 are thus opened, the closing ofa contact 70 causes the starting of motor 28. The functioning is moreover identical with that described above.

The invention is of course in no way limited to the applications most particularly described and shown as examples in the attached drawings.

What I claim is:

I. An apparatus for raising and lowering a scaffolding platform comprising at least one winch secured to said platform and driven by a motor so as to raise or lower the platform, locking means that can grip a cable extending along the travel path to stop the descent and hold said platform, control means which controls the unlocking of said locking means, control means which controls said motor in the direction for lowering said platfonn, coupling means to couple said unlocking control means and said motor control means in such a manner that the latter is necessarily actioned, to engage a lowering movement, after unlocking of said locking means and to stop the said lowering movement before the locking of said locking means.

2. An apparatus according to claim 1, wherein said locking means comprise a brake device with jaws capable of gripping the said cable and so arranged as to induce an autoclamping of the said brake in the direction of lowering of the platform and automatic release in the upward direction.

3. An apparatus according to claim 2. wherein said unlocking control means engage and operate at the limit of its control movement said motor control means in the direction of descent of the platform.

4. An apparatus according to claim 3, in which the said brake with jaws has two rods articulated at one end on the frame of the said winch and the other end of which coacts with the said jaws to induce their closing or opening when pivoted by an operating lever.

5. An apparatus according to claim 1, wherein the winch is driven by an electric motor with pushbuttons controlling the raising and lowering of the load, the operation of the said pushbutton for lowering being effected by a continued movement of the said unlocking control means of said locking means.

6. An apparatus according to claim 5, which comprises a plurality of supporting winches and a common control device which remotely controls all said unlocking control means of the various winches, which on reaching their limit of travel operate the control means of the said motors of the associated winches.

7. An installation for raising and lowering a scaffolding platform including at least one cable supporting the platform, a winch secured to said platform and having a grooved pulley in which is housed the said support cable and the rotation of which causes the raising or lowering of the platform up or down the said support cable, an electric motor driving the said winch in the raising or lowering directions, a safety device which automatically cancels a downward movement of platform, and which may be unlocked, a component operating the unlocking of the said safety device, a control component for the said electric motor to cause its operation in the downward direction and a device coupling the said operating components causing the unlocking of the safety device before the operation of the lowering control of the said motor and a control for stopping the descent before the locking of the said safety device.

Claims

1. An apparatus for raising and lowering a scaffolding platform comprising at least one winch secured to said platform and driven by a motor so as to raise or lower the platform, locking means that can grip a cable extending along the travel path to stop the descent and hold said platform, control means which controls the unlocking of said locking means, control means which controls said motor in the direction for lowering said platform, coupling means to couple said unlocking control means and said motor control means in such a manner that the latter is necessarily actioned, to engage a lowering movement, after unlocking of said locking means and to stop the said lowering movement before the locking of said locking means.

3. An apparatus according to claim 2, wherein said unlocking control means engage and operate at the limit of its control movement said motor control means in the direction of descent of the platform.