Patent Publication Number: US-7219879-B2

Title: Apparatus for signaling rotation of a winch to an operator thereof

Description:
FIELD OF THE INVENTION 
   This invention relates to apparatus for signaling rotation of a winch or hoist to an operator thereof and particularly for warning the operator when the drum of the winch or hoist is rotating. 
   The invention further relates to a method for signaling rotation of the drum to the operator. 
   BACKGROUND 
   The operator of a winch or hoist, either on a crane or mounted on a truck cannot always see the load that is being moved which can present a hazard. When an operator is raising or lowering a load, the operator is usually guided by an additional person giving directions either by radio or hand signals. Also known is a device of this type for indicating to the operator when the cable drum of the winch is rotating in either direction to move the load. The device for this can be mechanical or electrical. 
   It is typical of the present art that a drum rotation indicator is external to the winch and driven by a wheel that rides on a flange of the drum or is shaft-driven to an external output device. Both of these types of systems are susceptible to mechanical or environmental damage. 
   U.S. Pat. No. 3,922,605 shows an electrical winch drum rotation-indication system with a stepper motor driven from the winch drum to drive a tactile indicator for the operator. 
   U.S. Pat. No. 4,098,221 shows a drum rotation indicator with a readout plunger, that is located conveniently for the operator&#39;s hand. The plunger is moved linearly, in response to rotation of the drum, with sufficient force to give a positive feel, to the operator&#39;s hand. 
   U.S. Pat. No. 4,809,857 shows a drum rotation indicator with a rate generator connected to the winch which develops electrical pulses having a frequency proportional to winch rotational speed. A solenoid having a movable plunger is mounted in the cab of the crane where the vibration of the plunger can be sensed by a crane operator. 
   The following references are of general interest for showing cable drum indicators. U.S. Pat. No. 2,745,633; U.S. Pat. No. 2,776,814; U.S. Pat. No. 3,742,307; U.S. Pat. No. 3,750,130; U.S. Pat. No. 3,883,859; U.S. Pat. No. 4,156,467; U.S. Pat. No. 4,342,028; JP401043498. 
   SUMMARY OF THE INVENTION 
   An object of the invention is to provide apparatus for signaling rotation of a winch to an operator which avoids deficiencies of the known art and which employs an internal system within the winch to generate signals indicative of drum rotation. 
   The apparatus of the invention employs a system that uses an internal gear-driven optical system that outputs a signal to a solenoid that is incorporated in the operating lever of the winch. The solenoid vibrates as an indication of drum rotation and not necessarily proportional to the speed of the drum. 
   The invention provides apparatus for signaling rotation of the cable winding drum of the winch to the operating lever of the winch in which a drive means drives the cable winding drum to wind and unwind the cable from the drum and a self-contained optical system is internally supported in the winch and is driven by the drive means to signal rotation of the drum. 
   The optical system includes an optical disc driven in rotation by the drive means and an optical sensor facing the optical disc to produce pulsed output signals when the optical disc rotates. The pulsed output signals are transmitted to a solenoid operatively associated with the operating lever of the winch to produce vibration of the operating lever when the solenoid receives the pulsed signals from the optical sensor indicating rotation of the cable winding drum. 
   The self-contained optical system has a housing insertable into the winch for connection of the optical disc to the drive means. 
   The optical sensor produces pulses in correspondence with rotation of the disc and thereby in correspondence with rotation of the cable winding drum. 
   The optical disc is round and divided into segments which are alternately distinguished in appearance and the optical sensor is mounted on a fixed disc which is coaxial with the optical disc so that the optical sensor faces the segments on the optical disc as they rotate therepast. 
   In order to mount the optical system internally in the winch, a tubular sleeve is provided in the winch housing into which the self-contained unit is inserted. 
   The invention also provides a method for signaling rotation of the drum to the operating lever which comprises the steps of:
         driving the optical sensing unit when the cable winding drum of the winch rotates,   forming the optical sensing unit with a hollow stationary housing which rotatably supports a drive shaft driven in rotation when the cable winding drum rotates,   rotating an optical disc of the sensing unit within the interior of the hollow housing by the drive shaft when the drum rotates,   providing the optical disc with alternating distinguishing segments arranged around the axis of rotation of the optical disc,   sensing, from within the interior of the hollow housing, passage of the alternating segments as the optical disc rotates,   producing pulsed output signals based on the passage of the segments, and   transmitting the pulsed output signals to a solenoid supported by the operating lever to generate vibration of the operating lever and thereby indicate rotation of the cable winding drum to the operator       

   
     BRIEF DESCRIPTION OF THE DRAWING 
       FIG. 1  is a diagrammatic illustration, partly broken away and in section of a winch including a system adapted for signaling rotation of a cable winding drum of the winch to an operating lever of the winch. 
       FIG. 2  is a perspective view of a self-contained unit employed in the winch in  FIG. 1 . 
       FIG. 3  is a longitudinal sectional view of the unit in  FIG. 2 . 
       FIG. 4  is an end view of the unit in  FIG. 2 . 
       FIG. 5  is a front view of an optical disc of the self-contained unit as seen along line  5 — 5  in  FIG. 3 . 
   

   DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT 
   The drawings illustrate a hoist or winch  1  adapted for being mounted on a crane or truck (not shown). The winch  1  is operated by an operator (not shown) seated at a remote location next to an operating lever L which controls operation of the winch. Generally, the operator cannot always see a load being raised or lowered by the winch. The invention provides a system by which the operator is made aware that the winch is operating to raise or lower the load. 
   The system will be described hereafter with reference to the construction of the winch as illustrated in the drawing. 
   The winch  1  comprises a housing  2  and a cable winding drum  3  on which a cable  4  is wound or unwound depending on whether the load (not shown) attached to the cable  4  is being raised or lowered. The drum  3  has integral radial flanges  5  at the ends thereof. A rotatable shaft  6  extends through the cable drum  3 . The shaft  6  is rotatably supported in bearings  7  supported in pedestals  8 . A motor  9  drives the shaft  6  in rotation. The shaft  6  drives a sun planetary gear transmission  10  thereby driving the drum  3  in rotation. The motor  10  is controlled by operation of lever L by the operator in a manner well known to those skilled in the art. 
   The housing  2  has a side wall  11  to which is secured an open tubular support sleeve  12  which extends into the interior of housing  2 . 
   A self-contained signaling device  20  is secured in tubular support sleeve  12  for detecting rotation of the drum  3 . 
   The device  20  includes a hollow housing  21  which is fitted in support sleeve  12  and secured therewith. The housing  21  has an integral end flange  22  which is secured to an end flange of sleeve  12  to fix the housing  21  within sleeve  12 . An end plug  23  is secured in one end of housing  21 . A tubular stem  24  is formed at the opposite end of housing  21 . A drive shaft  25  is rotatably supported in stem  24  in an axially secured position and drive shaft  25  extends into the interior space in hollow housing  21 . The drive shaft  25  is driven from shaft  6  of motor  10  via a gear transmission  26 . Although the gear transmission  26  and gear transmission  10  have been shown separately, they can be integrated into a common gear transmission. The drive shaft  25  has a tang  27  at its free end which engages in a drive slot in the gear transmission  26  so that the drive shaft  25  is driven in rotation by the gear transmission  26 . 
   The self-contained signaling device  20  incorporates a system  30  ( FIG. 3 ) which detects rotation of drive shaft  25  and thereby of drum  3 . 
   The system  30  comprises an optical system which includes an optical disc  31  secured to drive shaft  25  and driven thereby from transmission  26  upon rotation of drum  3  on which the cable is wound and unwound. 
   The optical disc  31  is divided into a number of equal segments  40  distributed uniformly around the axis of rotation of disc  31 . The segments  40  are formed with alternating distinctive features, such as alternating dark and light segments, alternating colors or other distinctive appearance capable of being read by a sensor means  32  facing the optical disc  31 . The sensor means  32  is attached to a disc  33  which is fixed to housing  21  by engagement with end plug  23  such that the sensor means  32  is disposed within the interior of hollow housing  21 . 
   The disc  33  is fixed in housing  21  coaxially with optical disc  31  and the sensor means comprises an optical sensor element  34 , such as an IR sensor, arranged on the disc  33  to face the segments  40  on optical disc  31 . The sensor element  34  produces pulsed output signals as the alternating segments  40  on the optical disc  31  pass the sensor element  34 . The pulsed output signals of the optical sensor element  34  are fed to a conditioner circuit  35  fixed to the back surface of disc  33  and from which amplified output signals from the optical sensor element  34  are transmitted to a solenoid  36  by connecting cables  37  extending in passages  38  provided in plug  23 . Alternatively, the output signals from the conditioner circuit  35  can be transmitted wirelessly to the solenoid  36 , for example, as an RF signal or the like. The conditioner circuit  35  includes its own power supply, for example, a battery. 
   The solenoid  36  is incorporated into operating lever L so as not to interfere with operation of the lever. The pulsed output signals from the conditioner circuit  35  produce vibration of the solenoid  36  and of the operating lever L in which it is secured. 
   The optical system comprising the optical disc  31 , fixed disc  33  and conditioner circuit  35  is installed in housing  21 . Installation of the optical elements of the system therefore only involves mounting discs  31  and  33  within the housing  21 . The self-contained unit, inclusive of housing  21 , optical discs  31 ,  33 , conditioner circuit  35  and drive shaft  25 , is then installed within sleeve  12  such that drive shaft  25  engages gear transmission  26 . 
   Accordingly, the self-contained unit of the invention is simple to install and since the optical system is contained in the hollow space in housing  11  via sleeve  12 , the optical system is not subject to external influences and is maintenance free. 
   Although the invention is disclosed with reference to a particular embodiment thereof, it will become apparent to those skilled in the art that numerous modifications and variations can be made which will fall within the scope and spirit of the invention as defined by the attached claims.