DEVICE FOR THE PREVENTION OF A WINCH FROM TOPPLING

Abstract: Device for the prevention of reeling, especially in winches driven by vehicles, which winch is provided with a work cable reel rotating about a horizontal axis, the reeling operation of which is controlled by a control cable reel (6), which control cable reel is arranged for rotating together with the work cable reel in the inward reeling direction and thus for increasing the transmission capability of the means transmitting reeling power to the work cable reel, respectively for the reduction of the transmission capability of the power transmission means by preventing the inward reeling of the control cable. The device stops the inward reeling when the tilting of the winch or respectively of the vehicle carrying it exceeds a predetermined value relative to the vertical plane passing through the winch axis. For carrying out this operation the circumferential rim of the end flange of the winch control reel (6) is provided with toothing (5) and co-operating with locking elements mounted on the winch frame (8) construction on opposite sides relative the vertical plane passing through the control cable reel axis and swinging freely between a free position and a locking position, respectively, under the influence of gravitational force, whereby one locking element (1) is positioned on the upward side relative to the inward reeling direction of the control cable reel and correspondingly the other locking element on the opposite downward side.

Description: Device for the prevention of a winch from toppling The object of the present invention is a device with which the inward reeling operation of a winch is prevented, espe¬ cially a winch driven by a vehicle, when the tilting of the winch or correspondingly when the tilting of the drive ve¬ hicle exceeds a known pre-set limit. The device is especially intended for tractor driven winches that are used in the skidding of timber. The winch in ques¬ tion normally consists of a work cable reel rotating about a horizontal axis and mounted on a suitable frame construc¬ tion. The work cable reel receives its driving power from the tractor, commonly through friction clutch transmission. Driving power can also be transmitted, for example, by means of a hydraulic pump or hydraulic engine system which recei¬ ves its driving power for example from the tractor. In these winches the operation of the work cable reel is controlled by actuating either the friction clutch or the hydraulic system with the aid of a control cable .reel, which control cable reel has a tendency to rotate together with the work cable reel in the inward reeling direction. In the fully mechanical mode the control cable reel is arranged to advan¬ tage on the same axis as the work cable reel and by slowing down the control cable reel rotation the friction clutch slip transmitting power to the work cable reel is regulated and consequently the inward reeling power of the winch. The basic construction of such a mechanical winch is disclosed in the Finnish patent application No. 830749. Especially in forest skidding operations winch tractors are driven along special transportation tracks always to a new winching station as- work progresses, whereby from the same track timber is winched in from both sides of the track wit¬ hin the reeling range of the winch. The tractor will then be transverse to the direction of winching for a substantial part of the skidding operation. ' Winching distances with the winches of today are also remar¬ kably long, whereby particularly in thinning of forest areas marked for cutting the winch operator rather frequently lo¬ ses visual contact with the winch tractor. In these circums¬ tances the stability of the winch tractor has become a fun¬ damental problem as it may be exceeded particularly when winching in the sideward direction of the tractor a heavy entangling load over the terrain. In loss of visual contact the winch operator may cause the winch tractor to topple over. To counter the problem electrically operated monitoring means have been developed in radio-controlled winches,- which sense the degree of tilting of the winch relative to the vertical plane and halt the inward reeling winch operation upon the tilt exceeding a predetermined set value. This type of monitoring means can be realised in electrical¬ ly controlled winches by means of devices acting on the control system and at only a very small addition to the to¬ tal cost of the control system. However, electrically opera¬ ted monitoring means do not suit particularly well the natu¬ re of the simple operational mechanism of the fully mechani¬ cally operated and controlled, or hydraulically operated and mechanically controlled winches, but they cause a fundamen¬ tal contribution to the otherwise moderately kept total costs. On the aforementioned basis the object of the invention is the limitation of winch tilting and through that prevention of toppling by- providing the winch with mechanical means fo inhibiting reeling. Said safety function for the winch has been achieved for the aforementioned type of mechanically operated and controlled, or hydraulically driven and mecha¬ nically controlled winch in that the circumferential rim of at least one end flange of the control reel is furnished with toothing which co-operates with locking elements moun¬ ted on the winch frame construction on opposite sides rela¬ tive the vertical plane passing through the control cable reel axis and swinging freely between a free position and a locking position, respectively, under the influence of gravi tational force, whereby one locking element is positioned on the upward side of the inward reeling direction of the cont¬ rol cable reel and the other locking element correspondingly on the opposite downward side. The invention is explained by reference to the accompanying drawing in which: Fig. 1 presents the tilt prevention device in its fundamen¬ tal realisation in the normal vertical working position of the winch and Fig. 2 presents the tilting prevention device in its locked position when the winch tilt has exceeded a previously defi ned limit relative to the vertical plane. The figures present the basic construction of the horizonta control cable reel of the skidding winch described in the Finnish patent application 830749 as seen from the reel axi direction. The winch comprises a frame -construction 8, from which the winch is mounted for example to a three-point hitch of an agricultural tractor. According to the inventio at least one of the end flanges 6 of the control cable reel is furnished with peripheral ratchet teeth 5 and two lockin elements 1 and 2 are mounted on the winch frame on opposite sides of the winch. The locking elements 1 and 2 are mounte at their lower end so as to to freely swing to a limited ex¬ tent on axes la/2a so that they can tilt from a free positi¬ on to a locking position through the vertical plane. The tilting movement of the locking elements is arranged to oc¬ cur in a vertical plane normal to the winch axis. The free ends of the locking elements are .shaped as or cor¬ respondingly furnished with a suitably-formed hook for enga¬ ging the toothing 5 of the control cable reel end flange in the locking position, one of which locking positions in one of the tilt directions is presented in Fig. 2. For adjusting the operational sensitivity of the locking elements 1 and 2, in other words for adjusting the tilt ang¬ le in which the locking elements flop into their locking po¬ sition, the winch is furnished with adjustable tilt stops 3, 3a and 4, 4a, respectively. If during inward reeling of the winch such a side load is imposed on the work cable that the winching tractor begins to tilt in the work cable direction, the locking element co¬ ming to the higher position as the result of the tilt (element 1 in the circumstances of Fig. 2) swings against the circumference of the control cable reel end flange. It then engages the peripheral toothing of the control cable reel, whereupon the inward reeling movement of the control cable reel comes to a halt. Due to the winch construction the control cable reej. then remains that much behind the work cable reel that the friction clutch driving the work cable reel is released to its slipping position in which its transmitted power corresponds to the load imposed on the work cable. In this state the winch (and the winch tractor) remain in the tilted position corresponding to the adjusted position of the locking element. The tractor is made to des- cend to its vertical position by pulling at the control cable, whereby the control cable reel correspondingly rota¬ tes backwards relative to the work cable reel and the fric¬ tion clutch slip correspondingly increases. Thus the winch may controllably be lowered back to its vertical position under the effects of gravitational force, whereupon also th locking element 1 or 2 is released from its locking positio on the toothing 5 on retraction of the control cable and is returned to its free position under the influence of gravi¬ tational force. For restarting winching the load must be reduced or the obs tacle in front of it removed, after which winching can be continued with a loosened control cable. The corresponding operation can also be carried out with winches, the hydraulic drive of which is controlled in a corresponding manner with a control cable which has a ten¬ dency to reel inwards together with the work cable.

Claims: Patent Claims 1. Device for preventing reeling, especially in winches dri ven by vehicles, the frame construction (8) of which winch carries a work cable reel rotating about a horizontal axis, to which reeling power is transmitted by a mechanical fric¬ tion clutch, a hydraulic drive or corresponding power trans mission means controlled by a control cable reel (6), which control cable reel has a tendency to rotate together with the work cable reel in the inward reeling direction thus in creasing the power transmitting capability of the means transmitting reeling power to the work cable reel, respecti vely for reducing the power transmission capability of the power transmitting means by slowing down the inward reeling of the control cable, which device stops the inward reeling operation of the winch when the tilting of the winch or res pectively of the vehicle . carrying the same exceeds a prede¬ termined limit value relative to the vertical plane passing through the winch axis, c h a r a c t e r i z e d in that the circumferential rim of at least one of the end flanges of the control reel (6) is furnished with toothing which co operates with locking elements (1,2) mounted on the winch frame (8) construction on opposite sides relative to the vertical plane passing through the control cable axis and swinging freely between a free position and a locking posi¬ tion, respectively, under the influence of gravitational force, whereby one locking element (1) is positioned on the upward side of the inward reeling direction of the control cable reel and the other locking element (2) correspondingl on the opposite downward side. 2. A reeling " prevention device according to Claim 1, c h a r a c t e r i z e d in that the circumferential toothing (5) of the control cable reel (6) extends in a rotational direction corresponding to inward reeling of the winch and that the locking elements (1, 2) are furnished with a cor¬ responding engaging rim or with a hook, respectively. 3. A reeling prevention device according to Claims 1 or 2, c h a r a c t e r i z e d in that it is provided with ad¬ justing devices (3, 3a; 4, 4a) for adjusting the free posi¬ tion of the locking elements (1, 2) and at the same time fo adjusting their operational angle relative to the vertical plane.

Inventors: RUOKOLAINEN HANNU, RUOKOLAINEN, HANNU
Applicants: TEHOVINSSI KY
Application year: 1985
Main classification: B66D1
IPC codes: B66D1, B66D5