Block machines have two options to ensure consistent products are produced. These are the automatic feed control (see Service Bulletin – Adjustment and Operation of Automatic Feed Control) and the automatic feed time adjust.

Unlike the automatic feed control, when using the automatic feed time adjust, the cutoff bar does not move up or down, unless moved manually, but the feed time varies based on the actual finish time. When using the automatic feed time adjust, the cycles per minute of the machine will vary.

There are two versions of the automatic feed time adjust. Older block machine logics only created a window above the finish timer (Timer T4:1). If the actual finish time was lower than the finish timer (Timer T4:1), time was added to the feed timer (Timer T4:0). If the actual finish time was higher than the window, time was subtracted from the feed timer (Timer T4:0).

Since 2000, a majority of the block machines have an updated automatic feed time adjust logic that creates three windows above and below the finish timer. Each of these windows have a different feed time correction value associated with it. This allows for quicker adjustments to the feed time when there is a large discrepancy between the actual finish time and the finish timer (Timer T4:1) and a smaller adjustment to the feed time when the actual finish time is closer to the finish timer (Timer T4:1). The three feed time correction values and correction windows differ between block machines depending on the initial logic and any subsequent changes that have been made in the field. The values used in Figure 1 below may differ from your block machine and are for illustrative purposes only to explain the concept and the windows created. The values used to determine the amount of feed time correction and the windows used to create the three windows are called integers. These integers are listed in Figure 1 in parentheses. Example: (N7:172).

The auto feed time adjust can be looked at as a "Quality control" system. A concrete unit requires a certain amount of material and a certain finish time for proper density and texture. The automatic feed time adjust will maintain this density through varying the feed time.  The feed timer should remain fairly consistent if the concrete batches remain consistent. However, if the batches are too wet or too dry; or for material gradation changes, the cause of the batch changes must be determined.

Feed times and finish times will vary from material to material and from mold to mold. These will have to be determined through experience, and it is important that records of this are maintained, so that these values can be used as a starting point the next production run. This will help in maintaining production levels and maintaining a consistent quality product.

Figure 1. Graphic Example of the Automatic Feed time Adjust since 2000.

SAFETY BULLETIN

This notice is issued to advise you that some previously accepted shop practices may not be keeping up with changing Federal and State Safety and Health Standards. Your current shop practices may not emphasize the need for proper precautions to insure safe operation and use of machines, tools, automatic loaders and allied equipment and/or warn against the use of certain solvents or other cleaning substances that are now considered unsafe or prohibited by law. Since many shop practices may not reflect current safety practice and procedures, particularly with regard to the safe operation of equipment, it is important that you review your practices to ensure compliance with Federal and State Safety and Health Standards.

Always be sure proper guarding is in place for all pinch, catch, shear, crush and nip points.

Always be sure that all personnel are clear of the equipment before starting it.

Always be sure the equipment is properly grounded.

Always turn the main electrical panel off and lock it out in accordance with published lockout/tagout procedures prior to making adjustments, repairs, and maintenance.

Always wear appropriate protective equipment such as safety glasses, safety shoes, hearing protection and hard hats.

Always keep chemical and flammable material away from electrical or operating equipment.

Always maintain a safe work area that is free from slipping and tripping hazards.

Always be sure appropriate safety devices are used when providing maintenance and repairs to all equipment.

Never exceed the rated capacity of a machine or tool.

Never modify machinery in any way without prior written approval of the Besser Engineering Department.

Never operate equipment unless proper maintenance has been regularly performed.

Never operate any equipment if unusual or excessive noise or vibration occurs.

Never operate any equipment while any part of the body is in the proximity of potentially hazardous areas.

Never use any toxic flammable substance as a solvent cleaner.

Never allow the operation or repair of equipment by untrained personnel.

Never climb or stand on equipment when it is in operation.