Abstract:
Hand winch comprising a wind roll for receiving a flexible elongated member, an operation shaft engaged with the wind roll for transmitting forces therebetween, a friction brake including a gear member being in engagement with the wind roll and having a thrust position in which the gear member acts on a stationary member for generating braking forces directed oppositely to a sense of winding off the elongated member, characterized in that said gear member is movably mounted on the operation shaft such that, in case of winding off the elongated member, the gear member is displaced from a released position to said thrust position.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The invention refers to a hand winch which comprises a wind roll for winding off and up a flexible elongated member, as a belt, a band, a cable or the like. 
         [0003]    2. Description of the Prior Art 
         [0004]    Usually, the hand winch comprises an operation shaft engaged with said wind roll for transmitting manual operation forces between the wind roll and the operation shaft. Further, hand winches can comprise a friction brake so that an operating person does not need to hold high load forces when letting down boats or other heavy items. A known friction brake can be activated by screwing a crank handle onto the operation shaft and thereby a gear member, being in a gear wheel connection with the winding roll, comes into a friction contact with a stationary member which may be rigidly connected to the operation shaft. 
         [0005]    Such a hand winch suffers from the problem that the friction brake is to be deactivated by demounting the crank handle in order to unwind the elongated member in no load condition. Further, without the crank handle mounted, the brake system is not in an active operation mode. Therefore, the known hand winch implies security problems for operating persons. For instance, if accidentally the crank handle is demounted from the operation shaft, the friction brake is deactivated such that the load may wind off the elongated member “non-brakedly”. Further, if the crank handle is only unfastened beyond the thread slightly so that a friction contact between the gear member and the stational member cannot be built up, so that no brake is active and the load accelerated without contact, the load applied to the elongated member still drives the wind roll which makes the operation shaft holding the loosened crank handle to turn which may injure the operation person. 
         [0006]    It is an object of the invention to overcome the disadvantages of the prior art, particularly to provide a new hand winch which is improved with respect to more secure handling. 
       SUMMARY OF THE INVENTION 
       [0007]    This object is solved by features of claim  1 . 
         [0008]    Accordingly, the hand winch according to the invention comprises a wind roll for receiving the flexible elongated member and the operation shaft being engaged with the wind roll for transmitting forces there between. Further, the hand winch comprises a friction brake which includes a gear member being engaged with the wind roll and having a thrust position in which the gear member acts on a stationary member for generating braking forces directed oppositely to the sense of winding off the elongated member. According to the invention, the gear member is movably mounted on the operation shaft such that in case of winding off the elongated member, the gear member is displaced from a released position to the thrust position in no load condition. By the inventive technical measure of the invention, a completely internal friction brake is provided without having members being or even extending outside of the housing of the hand winch. In particular, no screwed connection of a crank handle is necessary in order to activate the friction brake. Rather, the friction brake self-activates automatically when a pulling load is applied to the elongated member. This measure improves the security aspects of a hand winch in that the winch does not allow an uncontrolled rapid winding off of the elongated member, i.e. without the control of the friction brake. It also allows the use of a removable handle, and still have the friction brake operate as described above. 
         [0009]    According to a preferred embodiment of the invention, the friction brake further includes a guiding device for displacing the gear member along the operation shaft from the released position to the shaft position. By realizing this structural measure, according to the invention it is clear that the gear member shall not be fixed to the operation shaft, rather is movably mounted onto the operation shaft. Preferably, the guiding device allows combined rotational and translatable movement of the gear member along the operation shaft towards the stationary member, in case of load on the elongated member. 
         [0010]    In a preferred embodiment of the invention, the gear member is threaded on the operation shaft. A sense of rotation of the thread is determined in that, in the case of winding off the elongated member, the gear member is displaced towards the stationary member under load conditions. 
         [0011]    In a further preferred embodiment of the invention, a gear member is biased by a thrust spring such that, in the case of winding up the elongated member, the gear member always remains in the thread engagement with the operation shaft. It is this technical measure of the gear member remaining in a threaded engagement which provides the automatic self-activation of the friction brake. As soon as a pulling load is applied to the wind roll and the wind roll starts to rotate, because of said thrust spring, the gear member turns and, due to the thread engagement with the operation shaft, the gear member is displaced towards the stationary member to generate friction forces to brake down the pulling movement caused by the load. 
         [0012]    A further independent aspect of the invention is described in the following which, however, can be combined with the above-mentioned aspects of the invention. 
         [0013]    The invention also refers to a hand winch comprising a wind roll for receiving a flexible elongated member, as a belt, a band, a cable or the like, and a friction brake defining an active braking status or a passive release status. According to the invention, an activating mechanism installed within the hand winch, activates the friction brake automatically, when load or pulling forces are applied to the elongated member. 
         [0014]    In a preferred embodiment of the invention, the actuating mechanism comprises a movable operation part or handle which may be a movably supported housing part of the hand winch. The operation part can manually be operated, particularly in order to deactivate the friction brake. The movable operation handle can be a pivoting housing part which is rotatably supported to a stationary housing basis. The operation handle comprises a guideway, particularly an opening, for the elongated member to extend therethrough. When load or pulling forces are applied to the elongated member, and consequently the elongated member is stretched, the operating handle is moved to an activating positing as its guideway follows the course of the stretched elongated member automatically. 
         [0015]    Preferably, the activating mechanism includes a stationary member as a brake disc. The stationary member can be rotatably mounted on the operation shaft and is optionally lockable at least in one turning sense around the operation shaft. This stationary member cooperates with the gear member, as a pinion, above-mentioned of friction brake. The gear member being rotatably supported on the operation shaft, too. This stationary member comprises a passive operation mode in which the stationary member can freely move together with the gear member. Further, the stationary member comprises an active operation mode in which the stationary member is fixed such that friction forces are generated between the stationary member and the gear member. 
         [0016]    In a further preferred embodiment of the invention, the actuating mechanism comprises a ratchet, as a latch, for the member rotatably mounted on the operation shaft supporting also the stationary gear member in that, in case of a load to the elongated moves the movable operation member which acts on the ratchet for blocking the stationary member so that it cannot turn together with the gear member at least in one turning sense. If the load is released, the movable operation part turns back by forces or manually so that the latch is released from the stationary member that they can freely rotate with the gear member. 
         [0017]    In a preferred embodiment, the ratchet is biased by a spring such that the ratchet is brought into a blocking engagement within a stationary member. Further, the operation handle can manually be operated or moved and then acts on the ratchet in a passive position such that the stationary member is released from the ratchet. 
         [0018]    Preferably, the stationary member is made of bronze. Alternatively, between the gear member and the stationary member, a ring of bronze can be positioned. 
         [0019]    Further features, advantages and characteristics of the invention will be described in view of the following description of a preferred embodiment by means of the enclosed drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0020]      FIG. 1  shows a perspective explosion view of elements of a hand winch according to the invention; 
           [0021]      FIG. 2 . shows a perspective view of the mounted hand winch according to  FIG. 1 , a friction brake being deactivated and a part of the housing being removed for better visibility of the interior of the hand winch; 
           [0022]      FIG. 3  is an enlarged perspective view according to  FIG. 2  without a pulling belt; 
           [0023]      FIG. 4  is a perspective view of the hand winch according to the  FIGS. 2 and 3 , a winding roll has been removed for better visibility of a ratchet of a friction brake activating mechanism; 
           [0024]      FIG. 5  is a perspective view of the hand winch according to  FIG. 2 , the friction brake being activated as the pulling belt is loaded and stretched; 
           [0025]      FIG. 6  is an enlarged perspective view according to  FIG. 5  without the pulling belt; and, 
           [0026]      FIG. 7  is a perspective detailed view according to  FIG. 6  the winding roll being removed for better visibility. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0027]    In  FIGS. 1 to 7 , the hand winch according to a preferred embodiment of the invention is generally denoted with the reference sign  1 . While in  FIGS. 2 ,  3  and  4 , the hand winch  1  is mounted in an operation mode, in which no load forces are applied to the hand winch and the belt loosely drops,  FIGS. 5 ,  6  and  7  show a loaded hand winch in which a friction brake is automatically activated, i.e. as soon as a load, as a boat or the like, is applied to the pulling belt  31 . 
         [0028]    In the following, the main elements of the hand winch  1  according to the preferred embodiment of the invention are introduced. 
         [0029]    According to  FIG. 1 , the hand winch  1  comprises a housing constituted as a basis by two L-formed side-walls  3 ,  5  which can be secured to each other via two bolts  7  and respective screws  9 . 
         [0030]    The bolts  7  receive sleeves  11  which extend internally and transversally from the one side wall  3  to the other side wall  5 . The sleeves  11  are designed to receive a stationary top part of housing  13  having two pairs of circular recesses  15  in which the sleeves  11  are received when the top part housing  13  is mounted onto the side walls  3 ,  5 . The top part housing  13  consists of two side wing walls  17 ,  19 , in which holes  21  are formed for supporting a primary axle  23  carrying a wind roll  25 . 
         [0031]    The wind roll  25  consists of two axial outer plates  27  ( 29 ) concentrically mounted on the primary axle  23 , one of which is formed as a dented gear wheel ( 29 ) having a large diameter. In between the gearwheel  29  and the plate  27 , an elongated element as a pulling belt  31  is wound. By turning clockwise, as indicated by arrow R, the belt  31  can be wound off from the wind roll  25 . In opposite rotation sense, the belt  31  is wound up to the wind roll  25 . 
         [0032]    The two L-formed walls  3 ,  5  of the housing support the primary axle  23  and a secondary axle by means of passages  35 ,  37  formed therein. The larger passage  37  is formed in the L-formed side wall adjacent to the dented gear wheel  29 . 
         [0033]    A gear member, namely a pinion  39 , mounted onto the secondary axle  33  can freely rotate on the axle  33  and comprises an internal thread  41  cooperating with an external thread  43  formed on the secondary axle  33 . The external thread is formed only partly along the secondary axle  33 . 
         [0034]    In a mounted position, on its circumference, the pinion  39  is in a meshed engagement with the dented gear wheel  29 , and on its inside, the pinion is threaded onto the secondary axle  33 . A thrust spring  45  rests on the inside of the L-formed side wall  3  and on one side of the pinion  39  such that the pinion  39  is ever pushed towards the L-formed side wall  5  adjacent to the pinion  39 . The threads of the pinion  39  and the axle  33  are designed such that, in case of a anti-clockwise rotation as indicated in  FIG. 1  by arrow P, the pinion  39  moves translationally along the axle  33  towards the L-formed side-wall housing  5  in order to come in a frictional engagement with an optionally stationary element of a completely internal friction brake. 
         [0035]    Said friction brake comprises an optionally stationary element a brake disc  47  mounted onto the secondary axle  33 , in specific operation mode of the friction brake. The brake disc  47  can freely rotate about the secondary axle  33 . The brake disc  47  comprises on its circular circumference a continuous row of teeth in order to provide a ratchet function. 
         [0036]    Said brake disc  47  cooperates with a latch  49  which is spring biased such that a protrusion  51  of the latch  49  comes into a meshed engagement between two adjacent teeth of the brake disk  47 . Thereby, the brake disk  47  is set stationarily. A rotation spring  53  is provided in order to push the latch  49  towards the brake disc  47 . 
         [0037]    On the top of the top part housing  13  a pivoting handle  55  is rotatably mounted on the primary axle  23 . The pivoting handle  55  comprises two semi-circular cut-offs  57  which are engaged by the sleeves  11  when the pivoting handle  55  is brought into a deactivating position in which the self-activating friction brake is deactivated. 
         [0038]    In order to hold the pivoting handle  55  in this position, two grasping springs  59  are fixed to the pivoting handle  55  for releasingly grasping the respective sleeves  11  in the said deactivating position. 
         [0039]    Internal friction brake is activated automatically when load is applied to the wind roll. 
         [0040]    All members of the friction brake for generating friction forces are positioned within the housing of the hand winch  1 . The internal friction brake consists of the pinion  39 , the brake disc  47  and the latch  49  and can be automatically activated when a load is applied to the belt  31 . 
         [0041]    In the case of application of pulling load to the belt  31 , the wind roll  25  including the dented gear wheel  29  intends to rotate in a clockwise sense R. Because of the meshed engagement between the pinion  39  and the gear wheel  29  and because of the thrust spring  45  urging the pinion  39  towards the brake disc  47 , the pinion  39  remains in the threaded engagement with the secondary axle  33 , such that by a minor rotation of the gear wheel  29  and due to the large transmission ratio between the pinion  39  and the gear wheel  29 , the pinion  39  is rotated counter-clockwise and therefore moved translationally along the axle  33  towards the brake disc  47 . As can be seen in  FIG. 7 , as the latch  49  is in the meshed engagement with the brake disc  47 , so that the latch  49  cannot rotate counter-clockwise and therefore is blocked. 
         [0042]    In this operation mode, the pinion  39  comes into a frictional engagement with the brake disc  47  and friction forces are generated between the brake disc  47  and the pinion  39  which are transferred into the gear wheel  29  obstructing a rotational moving of the gear wheel  29  and therefore stopping the movement of the load applied to the belt  31 . In this state, the belt  31  cannot be wound off the wind roll  25  by the load forces only. 
         [0043]    However, in order to let down the load applied to the belt  31 , a crank handle (not shown) can be plugged from the outside of the housing of the hand winch  1  onto the secondary axle  33 . By turning the crank handle the unit engaged of the pinion  39  and the axle  33  can be pivoted by overcoming the friction forces between the pinion  39  and the brake disc  47 , while the brake disc  47 , blocked by the latch  49 , remains stationary ( FIGS. 5 ,  6 ,  7 ). 
         [0044]    Preferably, the brake disc  47  is made of bronze, or a ring of bronze is positioned between the brake disc  47  and the pinion  39 . 
         [0045]    In the case that the crank handle is unintendedly released from the subsidiary secondary axle  33 , the pinion  39  remains in the friction contact with the brake disc  47  which keeps stopping a further winding off the belt  31  and therefore a movement of the load. 
         [0046]    Deactivation of the friction brake. In the case no load is provided to the belt  31 , usually the belt  31  is in a position as in  FIG. 2 . The pivoting handle  55  can manually be brought into a releasing position in which the handle  55  releases the spring-biased latch  49  from the brake disc  47  such that the brake disc  47  can freely rotate together with the pinion  39  around the secondary axle  33 . No friction forces are generated between the brake disk  47  and the pinion  39 . Consequently, the belt  31  can easily be wound off the wind roll  25  by manually pulling it. 
         [0047]    Additionally, if the belt  31  is completely wound off, in the releasing position of the pivoting handle  55 , a crank handle can be mounted to the primary axle  23  in order to drive the wind roll  25  for winding up the belt with high speed. It is to be considered that a connection between the crank handle and the primary axle  23  is designed such that the crank handle can drive the axle  23  only in one rotation sense for winding up the belt  31 . 
         [0048]    In the case, a load  31  is applied to the belt  31 , as seen in  FIG. 5 , the belt  31  is stretched and usually takes on specific more horizontal course. As the belt  31  extends through a passage way  61  formed in the pivoting handle  55 , the movable pivoting handle  55  automatically follows the course of the rigidly stretched belt  31  and pivots into an upswing activating position, as visible in  FIGS. 5 ,  6  and  7 . As seen in  FIG. 7 , the pivoting handle  55  releases the latch  49 , so that the rotating spring  53  pushes the latch  49  towards the teeth of the brake disc  47  which comes into a meshed engagement with the protrusion  51  of the latch  49 . As described above, in this operation mode friction forces are generated between the brake disc  47  and the pinion  39  which has moved towards the brake disc  47  because of its thread engagement with the axle  33  and the drive of the gear wheel  29 . 
         [0049]    It is understood that the features of the invention as disclosed in the above description, in the drawings, and with claims may be essential to achieve the invention, both by themselves or in any combination with each other.