Automatic Devices Company

A Track & Machine
For Every Purpose


SINGLE and MULTIPLE LINE MULE SHEAVES are our most popular pulley style for raising and lowering Austrian or Waterfall curtains, top masking panels for cinema applications, gym divider curtains.  Single and double sheaves are often used to divert curtain track operating cables around obstacles.  When used for lift applications, there are several benefits.  Vertically traveling curtains are a great option when there is not wing space to stack the curtain, or no floor stack to stack a divider curtain.  These sheave sets are available in either a horizontal or vertical orientation with several mounting options. 

Multiple line sheaves can be fabricated to accommodate up to 24 lift lines.  Ceiling, wall and pipe mount models are also available.  Most ADC sheaves are equipped with 3-inch diameter, self lubricating sleeve-bearing wheels and painted steel brackets with mounting holes for attaching to overhead structures.  When equipped with optional ball-bearing wheels, ADC sheaves may also be used for deploying light-weight scenery such as painted flats.  Steel ball-bearing wheels are also available for some models.  Contact the factory for details.



Contour Pulleys   Multiline Horizontal   Mule Blocks   Multiline Vertical   Single Line Vertical and Horizontal


CONTOUR PULLEYS are used for applications were multiple cables must follow a curved or irregular path.  Looking to do a lift curtain on a thrust stage or even a theatre with a central staging layout?  Contour pulley should be the first item on your B-O-M!  Cables can be taken to the end of the curtain or can be run overhead towards the rear of the stage at any point along the contour.  Pulleys are 2-1/2" diameter, nylon tired, ball-bearing wheels and should be used only with coated cables to prevent premature wear.  Pipe mount and surface mount models are available to accommodate up to 20 lift lines. 

MULE BLOCKS are a means of allowing line to pass over or around obstacles without rubbing or binding.  When a curtain needs to be manually operated from a remote location, or a machine's location does not provide proper cable alignment, mule blocks can solve your rigging issues.  Cord and cable will be protected from undue wear and operation will not be hindered by obstacles (HVAC units or ductwork, structural members, lighting fixtures etc.) or excessive drag. 

  • MB-1:  Single-wheeled ball-bearing pulley
  • MB-2:  Double-wheeled ball-bearing pulley designed for muling double lines.
  • MB-3:  Used with models 3503-A, 1703-A and 1403-A Center Take-Off Live End Pulleys.
  • MB-4:  Used with models 2803-A and 5003-A Center Take-Off Live End Pulleys.
  • MB-5:  Used with model 5003 Live End Pulleys.

SINGLE LINE PULLEYS available in both vertical and horizontal configurations, these pulleys are not used with multi-line systems but rather as individual mule or lift pulleys.

IMPORTANT NOTE:  Adding turns of any degree to operating lines increases the overall friction in the system.  Allowance must be made for this when selecting a curtain machine.  Mule blocks reduce the drag in the system, but do not eliminate it.  Manual systems with diverted operating cords will require more effort to operate and curtain machines will work harder.

 LIFT APPLICATIONS are governed by a number of variables and concerns.  Safety should be the first consideration in any project involving overhead rigging.  For this reason, ADC recommends that an outside structural engineer or qualified rigger be consulted for any lift application.  ADC operates exclusively as a manufacturer and as such does not offer system design or installation services.  Quotations are supplied to assist with the bid process, but should not be interpreted as a complete system design or B-O-M recommendation.  Additional or alternative equipment may be be required depending upon various project details.  ADC does not offer "CWANA" lift systems.