m be certain. Series 322 Load Frames Product Information Model 322.21 Model 322.31 Model 322.
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Preface Before You Begin Safety first! Other MTS manuals Before you use your MTS product or system, read and understand the Safety manual and any other safety information provided with your system. Improper installation, operation, or maintenance can result in hazardous conditions that can cause severe personal injury or death, or damage to your equipment and specimen. Again, read and understand the safety information provided with your system before you continue.
Conventions Conventions Documentation Conventions The following paragraphs describe some of the conventions that are used in your MTS manuals. Hazard conventions Hazard notices may be embedded in this manual. These notices contain safety information that is specific to the activity to be performed. Hazard notices immediately precede the step or procedure that may lead to an associated hazard. Read all hazard notices carefully and follow all directions and recommendations.
Conventions Hypertext links Series 322 Load Unit The electronic document has many hypertext links displayed in a blue font. All blue words in the body text, along with all contents entries and index page numbers, are hypertext links. When you click a hypertext link, the application jumps to the corresponding topic.
Conventions 10 Preface Series 322 Load Unit
Introduction Load Unit: Overview The load unit is the primary structure for most materials testing. It is a standalone testing unit. The load unit consists of the load frame plus additional parts, such as hydraulic crosshead lifts and control modules. Load units come in different sizes and shapes. The following illustration shows typical load units with common accessories. The load units are designed for testing materials.
What you need to know 12 Introduction MTS Systems Corporation assumes that you know how to use your controller. See the appropriate manual for information about performing any controllerrelated step in this manual’s procedures.
322 Load Unit: Component Identification 7 12 10 9 11 1 2 3 4 9 10 5 11 7 8 6 Component Descriptions (part 1 of 2) ITEM COMPONENT DESCRIPTION 1 Crosshead Moves the up and down the column to accommodate different sized specimens and fixtures. The crosshead is stiff and light weight; it is one end of the force train. 2 Crosshead locks Clamps the crosshead to the columns. The locks are hydraulically powered.
Component Descriptions (part 2 of 2) ITEM 4 COMPONENT DESCRIPTION The Emergency Stop button is standard; the other controls are optional. Control panel Grip controls Clamps and unclamps the hydraulically controlled grips during specimen installation and removal. Crosshead lift control Controls the crosshead lifts to raise and lower the crosshead hydraulically. Emergency Stop Removes hydraulic pressure from the load unit and issues an interlock signal to the controller to stop the test program.
Load frame The load frame is the basic structure which provides the reaction mass for the force train. The T-slot base of the load frame is one end of the reaction mass and the crosshead is the other end of the reaction mass. Installing a specimen and other fixtures or components between the load unit base and the crosshead create a force train. The load frame and the other hydraulic components mounted to it collectively create the load unit.
Force The force transducer (also called load cell or force sensor) measures the amount of tension or compression and rotational torque applied to it. It has four strain gages that form a balanced Wheatstone bridge. When forces are applied to the bridge, it becomes unbalanced and produces an electrical signal that is proportional to the force applied to it. The force transducer is a resistive device and requires a DC conditioner to process the axial signal from the Wheatstone bridge.
322 Basic Specifications a b c e d f Fatigue Ratings, Dimensions, and Weight MODEL 322.21 MODEL 322.31 MODEL 322.41 Load unit fatigue rating 100 kN (22 kip) 250 kN (55 kip) 500 kN (110 kip) A maximum specimen/grip clearance* 1270 mm (50.0 in) 1575 mm (62.0 in) 2057 mm (81.0 in) B width between columns 533 mm (21.0 in) 635 mm (25.0 in) 762 mm (30.0 in) C height — with standard columns† 2489 mm (98 in) 3010 mm (118.5 in) 3677 mm (144.75 in) D table height 838 mm (33.0 in) 864 mm (34.
a c b e d ANSI Standard B.5.1 T-Slot Dimension* MODEL T-BOLT SIZE A B C D E 332.21 0.75 in 0.81 in 1.21 in 0.62 in 0.59 in 1.44 in 322.31 1 in 1.06 in 1.82 in 1.00 in 0.82 in 1.82 in 322.41 1 in 1.06 in 1.82 in 1.00 in 0.82 in 1.82 in * Minimum tolerances. DIN Standard 650 T-Slot Dimension* MODEL Introduction A B C D E 332.21 22 mm 22 mm 38 mm 22 mm 16 mm 37 mm 322.31 28 mm 28 mm 48 mm 28 mm 20 mm 46 mm 322.
d e h f g a c b T-slot Platen Dimensions — U.S. Customary T-slot Platen Dimensions MODEL * C D E 1000 mm (40.0 in) 355.6 mm (14.0 in) 508.0 mm (20.0 in) 864 mm (34.0 in) 1000 mm (40.0 in) 431.8 mm (17.0 in) 1067 mm (42.0 in) 1500 mm (60.0 in) 533.4 mm (21.0 in) A B 332.21 711 mm (28.0 in) 322.31 322.41 † F G H 127.0 mm (5.0 in) 228.6 mm (9.0 in) 101.6 mm (4.0 in) 127.0 mm (5.0 in) 508.0 mm (20.0 in) 152.4 mm (6.0 in) 254.0 mm (10.0 in) 127.0 mm (5.0 in) 127.0 mm (5.
c b d a Deflections and Spring Rates 322.21 322.31 322.41 Deflections* 100 kN (22 kip) 250 kN (55 kip) 500 kN (110 kip) A-B base 0.15 mm (0.006 in) 0.18 mm (0.007 in) 0.20 mm (0.008 in) B-C columns 0.10 mm (0.004 in) 0.20 mm (0.006 in) 0.20 mm (0.008 in) C-D crosshead 0.13 mm (0.005 in) 0.20 mm (0.010 in) 0.25 mm (0.10 in) A-D overall frame 0.38 mm (.015 in) 0.53 mm (0.021 in) 0.66 mm (0.026 in) Spring rates* 2.6 x 108 N/m (1.5 x 106 lb/in) 4.6 x 108 N/m (2.6 x 106 lb/in) 7.
Series 322 Load Unit Introduction 21
Series 661 Force Transducer: Specifications The force transducer used with this system is a Series 661 Force Transducer. The following are the specifications for the force transducers. SPECIFICATION PARAMETER Maximum excitation voltage 15 V DC Bridge resistance 350 ¾ Maximum crosstalk 1.0% of full scale torsional to load Hysteresis 0.08% of full scale (250 N–2.5 kN) 0.05% of full scale (5 kN–50 kN) 0.15% of full scale (100 kN–500 kN) 0.20% of full scale (1000 kN) Nonlinearity 0.
MODEL LOAD CAPACITY WEIGHT THREAD SIZE* 661.20-01 25 kN (5.5 kip) M27 x 2.0 mm x 31.7 mm (1 - 14 UNS-3B x 1.25 in) 9.75 kg (21.5 lb) 661.20-02 50 kN (11 kip) M27 x 2.0 mm x 31.7 mm (1 - 14 UNS-3B x 1.25 in) 9.75 kg (21.5 lb) 661.20-03 100 kN (2.2 kip) M27 x 2.0 mm x 31.7 mm (1 - 14 UNS-3B x 1.25 in) 9.75 kg (21.5 lb) 661.22-01 250 kN (3.3 kip) M36 x 2.0 mm (1 1/2 - 12 UNC-2B) 13.2 kg (29 lb) 661.23-01 500 kN (5.5 kip) M52 x 2.0 mm x 48.3 mm (2.0 - 12 UN-2B x 1.9 in) 16 kg (35.
Introduction Series 322 Load Unit
Safety General Safety Practices This section provides information about safety issues that pertain to servohydraulic systems in general. These issues include statements to the intended use and foreseeable misuse of the system, the hazard zone, definition for the graphical hazard labeling that is affixed to your product, and other (more general) safety information that relates to the high-pressure and highperformance characteristics of MTS servohydraulic systems.
If you have system related responsibilities (that is, if you are an operator, service engineer, or maintenance person), you should study safety information carefully before you attempt to perform any test system procedure. You should receive training on this system or a similar system to ensure a thorough knowledge of your equipment and the safety issues that are associated with its use.
Locate and read hazard placards/labels Find, read, and follow the hazard placard instructions located on the equipment. These placards are placed strategically on the equipment to call attention to areas such as known crush points and electrical voltage hazards. Locate Lockout/tagout points Know where the lockout/tagout point is for all of the supply energies associated with your system.
Keep bystanders safely away Wear proper clothing Remove flammable fluids Know compressed gas hazards 28 Safety Keep bystanders at a safe distance from all equipment. Never allow bystanders to touch specimens or equipment while the test is running. Do not wear neckties, shop aprons, loose clothing or jewelry, or long hair that could get caught in equipment and result in an injury. Remove loose clothing or jewelry and restrain long hair.
Observe the following safety practices when you work with high-pressure air or gases: • When you charge an accumulator, follow all the charging instructions provided in the appropriate product information manuals. When precharging accumulators, properly identify the type of gas to be used and the type of accumulator to be precharged. Use only dry-pumped nitrogen to precharge nitrogen-charged accumulators. (Dry-pumped nitrogen can also be labeled “oil pumped” or “dry water pumped.
On rare occasions, a fastener can fail even when it is correctly installed. Failure usually occurs during torquing, but it can occur several days later. Failure of a fastener can result in a high velocity projectile. Therefore, it is a good practice to avoid stationing personnel in line with or below assemblies that contain large or long fasteners. Practice good housekeeping Keep the floors in the work area clean.
Provide adequate lighting Ensure adequate lighting to minimize the chance of operation errors, equipment damage, and personal injury. You need to see what you are doing. Provide means to access out-of-reach components Make sure you can access system components that might be out of reach while standing on the floor. For example ladders or scaffolding might be required to reach load cell connectors on tall load units.
Do not disturb sensors Do not bump, wiggle, adjust, disconnect, or otherwise disturb a sensor (such as an accelerometer or extensometer) or its connecting cable when hydraulic pressure is applied. Ensure secure cables Do not change any cable connections when electrical power or hydraulic pressure is applied. If you attempt to change a cable connection while the system is in operation, an open control loop condition can result.
Hazard Icons Following are the hazard icons used on the MTS products. ICON DESCRIPTION Moving parts; pinch points. Keep clear of areas noted with this label High pressure fluid or gasses. Do not tamper with fittings or hoses. Possible explosive or flying debris. Wear appropriate protection such as safety goggles and hearing protection. Possible tipping hazard. The machine should only be moved by qualified riggers familiar with moving heavy, delicate equipment.
ICON DESCRIPTION Alternate read the manuals or instructions. Become familiar with safety information. Also become familiar with operating and maintenance information. Hot surfaces. Possible burn hazard. Wear personal protective equipment such as gloves when working near hot surfaces. Object is heavy. Requires more that one person to lift and move.
322 Load Unit: Hazard Labels This section provides information on hazard labeling. Part numbers are provided should replacement labels be necessary due to damage. Front Preloader torque lube and torque xxx N·m xxx ft-lbf ! Warning If lift cylinder line is opened, air may enter, causing crosshead to drop when unlocked. Bleed both cylinders before unlocking crosshead. ! Warning High force moving parts. Can cause severe injury or equipment damage. Stay clear and use eye protection while test is in progress.
Rear Force Transducer model s/n cpty kN lbs ! Warning High force moving parts. Can cause severe injury or equipment damage. Stay clear and use eye protection while test is in progress. Read instructions before operating or servicing. Load Unit model no. part no. rev. serial no. force cpty. mg. date ! Warning If lift cylinder line is opened, air may enter, causing crosshead to drop when unlocked. Bleed both cylinders before unlocking crosshead. Service Manifold model no. s/n ass’y no. rev. 3000 psi 20.
322 Load Unit: Crush Point Hazards It is important to stay clear of any potential crush points when the system is operating. Know where the crush points are in your system and protect yourself and others from those crush points with appropriate safety devices. The following paragraphs describe crush points and precautions to take while working around crush points.
Safety Series 322 Load Unit
Inspect for Shipping Damage Installation Load Unit installation consists of these four major tasks — • Inspect for Shipping Damage • Unpack and Move the Platen • Install the Crosshead Assembly • Make Connections, Bleed Lifts, Tighten Columns Special equipment needed — • An overhead crane and lifting slings or chains capable of lifting the load unit Load Unit Standard Dimension Platen Weight 322.21 28 X 40 in 711 X 1016 mm 3000 lb 1370 kg 322.
Unpack and Move the Platen Unpack and Move the Platen Note You can move the platen and crosshead assembly with a forklift as long as they’re attached to their pallets. The load unit is extremely heavy. The weight of the load unit can seriously hurt you and damage your load unit. Do not allow the load unit to drop or topple. Observe the following precautions: • Ensure that your chains, slings, and crane have a working capacity greater than the load unit’s weight.
Unpack and Move the Platen 4. Attach the lifting straps to the lifting eyes. Adjust them so each lifts about the same weight. Keep your straps as straight as possible — do not let them get more than 30° from the vertical. 30° maximum Attach straps 5. Lift the platen clear of its pallet and move it carefully to its installation site. 6. Lower the platen onto the isolation pads. If the platen is not level, install stock metal shims between the pads and the floor.
Install the Crosshead Assembly Install the Crosshead Assembly There is a possibility of the crosshead assembly suddenly dropping — You can be seriously hurt and your assembly badly damaged. To reduce the hazards in this procedure, observe the following precautions: • Always lift the crosshead assembly using the lifting eyes screwed into the crosshead — never with eyes screwed into the columns. • Never wrap chains around the crosshead or columns or actuator.
Install the Crosshead Assembly 1. Tighten the crosshead manual locking bolts. Manually locked crosshead Check the torque on the locking bolts, following the pattern in the following figure. Make sure the locks are tight.
Install the Crosshead Assembly Do not tighten the bolts for the hydraulic locks. Mistakenly tightening the bolts for the hydraulic locks along with the crosshead’s manual locking bolts could make the crosshead bind when it’s unlocked causing personal injury and equipment damage. Hydraulically locked crosshead Tighten the manual locking bolts, following the pattern in this figure. Make sure the locks are tight.
Install the Crosshead Assembly 4. Attach the lifting straps to the lifting eyes. Slowly and carefully bring the assembly to an upright position.
Install the Crosshead Assembly 5. Attach the crosshead assembly to the platen. Tighten the column cap screws to 25% of their full torque value.
Install the Crosshead Assembly Note Skip the next two steps if you do not have hydraulic lifts. 110 N·m (80 lbf·ft) Parallel Clamp position mark 75 N·m (55 lbf·ft) 6. Assemble the cylinder clamp around the lift cylinder. Start the clamp’s cap screws into the platen. Use the cylinder’s clamp marks to get its height right. Get the cylinder parallel to the column. Torque the cap screws to 55 lbf·ft (75 N·m). A.
Make Connections, Bleed Lifts, Tighten Columns Make Connections, Bleed Lifts, Tighten Columns 1. Make all hydraulic and electrical connections to the load unit. Hydraulic lock hoses Force transducer cable Emergency Stop cable Servovalve cable Pilot pressure line Lift cylinder lines Pressure and return lines LVDT cable Air trapped in the lifts may let the crosshead drop as soon as you unlock it. You can be hurt and your load unit damaged.
Make Connections, Bleed Lifts, Tighten Columns 2. Bleed Hydraulic Lift Cylinders. Bleed both hydraulic lift cylinders. Refer to “Load Unit: Bleed the Hydraulic Lift Cylinders” on page 69 for the procedure. Mistakenly loosening the bolts for the hydraulic locks along with the crosshead’s manual locking bolts could let the crosshead slip, especially when it is under load. You could be hurt and your equipment damaged. 3.
Make Connections, Bleed Lifts, Tighten Columns 100% torque 5. Tighten the column cap screws to their full torque values. 322.21 680 lbf·ft 920 N·m 322.31 1360 lbf·ft 1840 N·m 322.41 1360 lbf·ft 1840 N·m 6. Check the alignment of the force transducer with the actuator.
Operation Load Unit: Operation Preface This section describes the load unit controls, crush point hazards, and procedures performed during the normal, day-to-day operation of the load unit. Application note Special considerations must be followed when using low force transducers in a high force systems. Small force transducers are commonly used in larger systems. You need to be aware that the load unit can produce forces that exceed the rating of the low force transducer.
322 Load Unit: Control Module The controls for the load unit are located on a module mounted to the front of the load unit. For some configurations, the grip controls and lift and lock controls might be on separate control modules. Load Unit Controls (part 1 of 2) CONTROL DESCRIPTION Hydraulic Grip Controls Controls the optional hydraulic grips. Hydraulic grips let you quickly and easily install and remove specimens. The left handle controls the lower grip and the right handle controls the upper grip.
Load Unit Controls (part 2 of 2) CONTROL DESCRIPTION Rate Adjusts how fast the grips clamp and unclamp. Adjust the control clockwise to slow the clamping of the specimen. Rate Crosshead Lift/Lock Controls Controls the movement and clamping of the crosshead. The left handle raises and lowers the crosshead. The right handle locks and unlocks the crosshead. The crosshead must not be moved while it is clamped.
322 Load Unit: Crush Point Hazards It is important to stay clear of any potential crush points when the system is operating. Know where the crush points are in your system and protect yourself and others from those crush points with appropriate safety devices. The following paragraphs describe crush points and precautions to take while working around crush points.
CAUTION When changing hydraulic grips, make sure you cap or plug the hydraulic hoses when removed to prevent oil spillage. Oil spillage can create an environmental concern and slippery surface that can cause personal injury. Promptly clean up any oil that might have spilled when hoses were removed. WARNING The crosshead is very heavy. A dropping crosshead can crush hands, damage grips, and smash specimens. Be careful when working in a crush zone.
2. Set the crosshead position. The crosshead position depends on the length of the specimen being tested, the starting position of the actuator, and the size of the fixtures or grips being used. 3. Install the specimen. Specimen installation varies according to the type of grip being used. See the appropriate grip manual for installation instructions.
Load Unit: Position the Crosshead Hydraulically 1. This step pressurizes the lift actuators. The crosshead might have shifted position while hydraulic pressure was turned off. Briefly turn the Crosshead Lift/Lock Controls to the lift crosshead position to apply a slight upward pressure to the crosshead. Then return the lift control to the stop position. 2. Use the Crosshead Lift/Lock Controls to unclamp the crosshead. Wait 30 seconds for the pressure in the crosshead locks to drop to zero.
Load Unit: Position the Crosshead Manually This procedure describes how to position a crosshead for a load unit with no hydraulic crosshead lifts or locks. WARNING The crosshead is very heavy. A dropping crosshead can crush hands, damage grips, and smash specimens. Observe the following precautions to reduce the possibility of unexpected crosshead movement: • Ensure that the crosshead is locked.
4. Loosen the crosshead locking bolts in 1/4 turn steps (counterclockwise). The following figure shows the sequence of loosening the crosshead bolts. Load Unit Rating 100 kN (22 kip) 190 N·m (140 lbf·ft) Load Unit Rating 250 kN (55 kip) 271 N·m (200 lbf·ft) Load Unit Rating 500 kN (110 kip) Rear 271 N·m (200 lbf·ft) Load Unit Rating 500 kN (110 kip) Front 271 N·m (200 lbf·ft) 5. Raise or lower the crosshead using the overhead crane. 6. Manually claim the crosshead to lock the crosshead into position.
WARNING The crosshead is very heavy. A dropping crosshead can crush hands, damage grips, and smash specimens. Observe the following precautions to reduce the possibility of unexpected crosshead movement: Prerequisite • Ensure that the crosshead is locked. • The overhead crane and lifting chains must be able to support the weight of the crosshead (see the Crosshead Weight table below). • Center the crane directly over the load unit.
Load Unit: Adjust the Grips’ Clamp Rate The clamp rate determines how fast the grip can clamp a specimen. 1. Ensure that both the upper grip control and lower grip control are in the unclamp position. 2. Turn on electrical power at the test controller. 3. Turn on low or high hydraulic pressure. 4. If needed, move the crosshead or actuator so that the dummy specimen can be easily installed in the lower grip. 5. Turn the Rate control fully clockwise for the slowest clamp speed.
A. Watch the speed at which the lower grip clamps and unclamps the specimen. B. Adjust the Rate control counterclockwise for the desired speed. Load Unit: Adjust the Grips’ Clamp Force The Pressure control adjusts the hydraulic pressure applied to the grips. The Rate control adjusts the grips’ clamping speed. They must be adjusted before the grips can be used. The amount of hydraulic pressure applied depends on the type of grips you are using and what you are gripping.
5. Adjust the Pressure control for the desired hydraulic pressure. Pressure More Less 6. If you exceed the desired pressure setting, adjust the Pressure control counterclockwise 1/2 turn. If pressure setting exceeds 20 MPa (3000 psi) cycle (clamp and unclamp) one of the grips. Return to Step 5.
Operation Series 322 Load Unit
Maintenance 322 Load Unit: Maintenance Intervals Load Unit: Daily Inspections 67 Load Unit: Clean the Columns Load Unit: Prevent Rust 66 67 68 Load Unit: Bleed the Hydraulic Lift Cylinders Load Unit: Adjust the Hydraulic Locks 69 71 Load Unit: Lubricate the Crosshead Locking Bolts Load Unit: Align the Force Transducer 74 75 111 Accumulator: Maintenance Overview 81 111 Accumulator: Check and Change Precharge Pressure 244 Actuator: Maintenance 298 HSM: Maintenance 86 86 252 Servovalve: Mainte
322 Load Unit: Maintenance Intervals The following table lists the recommended interval for each of these procedures. 66 Maintenance WHAT TO DO WHEN TO DO IT Make daily inspections Before the start of each day’s testing. Clean the load unit columns When the columns become greasy or dirty. Prevent rust Depends on the operating environment; more often in humid environments.
Load Unit: Daily Inspections Before the start of each day’s testing, do a quick inspection of your load unit. Following are typical things that should be checked daily: • Ensure that there are no leaks from lifts or locks. • Ensure that there are no leaks from the actuator, hydraulic service manifold, servovalve, or accumulators. • Ensure that electrical connections are tight, with no frayed or poorly routed cables. • Ensure that hoses are routed properly and fittings are not leaking.
Load Unit: Prevent Rust Where you operate the load unit determines how often you take rust prevention measures. Humid and corrosive environments require more prevention. Recommended supplies: • Ethanol • Silicone spray • 000 emery cloth • Touchup paint • Metal primer paint • Lint-free cloths WARNING The crosshead can slip if the columns are still damp with kerosene. You can be hurt and your equipment damaged. The crosshead locks cannot securely clamp on damp columns.
Load Unit: Bleed the Hydraulic Lift Cylinders Bleed both hydraulic lift cylinders whenever the crosshead does not move smoothly. Also bleed them whenever the sealed side of the hydraulic system has been opened to air. The following figure shows the location of the bleed ports for the two types of lifts commonly used. Bleed ports CAUTION The crosshead can slowly drift down the columns if the locks are turned off and the hydraulic pressure is turned off.
5. If there is a specimen in the load unit, remove it. WARNING The lifts contain hydraulic fluid under high pressure. If the bleed port screw is unscrewed all the way, the screw can fly out of its port at high velocity and it could hurt you or damage your equipment. Unscrew the bleed port screw no more than 1/2 turn to vent the trapped air. 1/2 turn maximum Open to Bleed 6. Use a 1/8 inch hex key (or slotted screwdriver, depending on model number) to open one of the bleed ports.
10. Turn on high hydraulic pressure. If pressure was reduced at the hydraulic power unit, restore full pressure. 11. Briefly turn the Lift Control to the lift crosshead position to pressurize the lift cylinders. Then return it to the stop crosshead position. 12. Unlock the crosshead and exercise the crosshead. Then return to the stop crosshead position. Raise and lower the crosshead to check for smooth operation. Lock the crosshead. 13.
4. Use the Lock Control to lock the crosshead. Then torque the manual crosshead locking bolts in the order shown in the following illustration. 2 1 Load Unit Rating 100 kN (22 kip) 100 N·m (140 lbf·ft) 3 1 3 1 4 Load Unit Rating 250 kN (55 kip) 271 N·m (200 lbf·ft) Load Unit Rating 500 kN (110 kip) 2 4 2 271 N·m (200 lbf·ft) 5. Turn off hydraulic pressure. 6. Use the Lock Control to the unlock crosshead position to remove pressure from the hydraulic locks.
7. Tighten each lock’s cap screw until its piston bottoms out. Then loosen and hand-tighten each cap screw. Tighten Bottom out position Loosen, then hand tighten 8. Loosen each of the hydraulic locks’ cap screws 1/4 turn. Loosen1/4 turn 9. Turn on electrical power at the test controller if you have not already done so. 10. Reset any active interlocks at the test controller. 11. Turn on high hydraulic pressure. 12.
Load Unit: Lubricate the Crosshead Locking Bolts Lubricate the locking bolts in a manually locked crosshead whenever they begin to be hard to tighten or sticky when loosened. 1. Remove the covers on the ends of the crosshead. The crosshead covers must be removed to lubricate the crosshead locking bolts. Four 1/4-20 screws (two top, two bottom) on each cover need 5/21 hex (not included). Hand tighten when reinstalling the covers. 2. Position the crosshead at a comfortable working height.
Load Unit: Align the Force Transducer This section describes how to align a force transducer with the load unit actuator. The load units shown may vary from what you may have. Load units can come with two types of transducer mounting hardware. One preloads the force transducer with a hex nut; the other uses a preloader collar with jackbolts or captive set screws. Some load units use a preloader collar with six or eight internal jackbolts to preload the force transducer.
B. Set and enable the test controller’s upper and lower limit detect interlocks to limit the actuator’s movement to 2 mm (0.10 in) in each direction. C. Move the crosshead so there is about 360 mm (14 in) between the top of the actuator and the bottom of the force transducer. D. Lock the crosshead. WARNING Alignment takes place in a crush zone with hydraulic pressure on. Hands can be crushed and equipment can be damaged equipment when hydraulics are turned on. Be careful when working in a crush zone.
3. Check the alignment. In this step, you check the alignment between the force transducer and the actuator. . Read along the edge Zero Read along the edge Zero 360° 360° Attaching and Zeroing the Indicator A. Attach the dial indicator to the actuator. On a low profile force transducer, adjust the indicator to take the reading along the edge of the loading surface. On cylindrical style force transducers, adjust the indicator so that its stylus just touches the polished bottom edge of the transducer.
4. Prepare the force transducer. Depending on the type of force transducer you have, perform one of the following procedures: Hex nut mount only • Hex nut mount only • Preloader collar mount only The following procedure applies only to force transducers that are mounted to the crosshead with a single hex nut. A. Put blocks of wood between the actuator and the force transducer. They will support the force transducer when its mounting nut is loosened. B. Loosen the mounting nut.
Preloader collar mount only The following procedure applies only to force transducers that are mounted to the crosshead using a preload collar. Loosen the six jack bolts or setscrews in 1/4 turn steps to remove most of the tension on the preloader collar, following a standard crisscross torque sequence. • If your preloader collar has jackbolts, remove and lubricate them one at a time. Lubricate the washer underneath the jackbolt.
B. Tighten to 5% of the torque recorded on the identification plate. Hex nut—Tighten the nut to 5% of the final torque shown on the identification plate. Preloader collar—Tighten the jackbolts or setscrews to 5% of the final torque shown on the identification plate. 1 C. Rotate the indicator to see if the TIR is still 0.038 mm (0.0015 in) or less. If not, loosen the nut or preloader collar and return to Step 4. (Loosen the preloader collar following the sequence shown below.) D.
C. Turn the load unit’s hydraulic pressure to off. Unscrew/Tighten Anti-Rotate Actuator—Tightening the Cap Screws D. If your load unit has an antirotate actuator, tighten the four antirotate cap screws to a torque listed in the following table. (The actuator force rating is stated on an identification plate at the rear of the load unit.) ACTUATOR FORCE RATING TORQUE RATING 25 kN (5.5 kip) 3.7 N·m (2.
Use the following guidelines to determine when maintenance is required. 82 • Check the precharge pressure at periodic intervals. The length of time between checks depends on how the system is used. Some factors to consider when establishing this time interval are operating frequency, displacement, and duration. Start with one month intervals until you determine another interval is more appropriate. • Maintain a log book on the condition of the precharge at each check.
111 Accumulator: Check and Change Precharge Pressure Special equipment Prerequisite An accumulator charging kit (MTS part number 376986-01) is for any Series 111 Accumulator: To prepare the accumulator for precharge check: WARNING Accumulators are pressurized devices. Pressurized accumulators and their parts can become lethal projectiles if disassembled and can cause death to persons and/or damage to equipment. Do not remove an accumulator that is pressurized.
2. With an open-end wrench, turn the locknut counterclockwise on the accumulator valve assembly to open the valve. Read the pressure on either the high or low accumulator charging kit pressure gage. • If the pressure reading is other than the required pressure level recorded on the accumulator, continue with the next subsection, “Change the Precharge Pressure”.
WARNING Mixing gases can produce unpredictable results. Do not use another gas to precharge an accumulator. Use only dry nitrogen gas to precharge accumulators. 3. Connect the nitrogen supply hose from the supply bottle pressure regulator output to the input check valve on the charging kit. 4. Open the nitrogen bottle valve. Check the nitrogen bottle pressure gage on the regulator. (The bottle must contain sufficient pressure to provide an adequate gas volume.) 5.
244 Actuator: Maintenance The series 244 Actuator is designed for extended periods of operation without extensive maintenance requirements. A summary of the routine maintenance procedures is listed below: Weekly Clean exposed areas of the actuator piston rod with a clean, dry, lint free rag. If the actuator is continually exposed to a dirty operating environment, clean the piston rod on a daily basis. Monthly Inspect actuator piston rod and seals for excessive wear and/or leakage.
CAUTION Mixing different brands of hydraulic fluid can contaminate your system. Contaminated hydraulic fluid can cause premature wear of the hydraulic components in your system. Do not mix different brands of hydraulic fluid. MTS Systems Corporation recommends using Mobil DTE-25 or Shell Tellus 46 AW hydraulic fluid. The filter element should be replaced whenever: • The indicator on the top of the filter housing is in the bypass position, which indicates a dirty filter condition.
252 Servovalve: Maintenance Overview Maintaining the Series 252 Servovalves typically involves changing the filter element (Series 252.3x only) and setting the mechanical null adjustment. Except for these procedures, further disassembly, inspection, or repair of the servovalve is not recommended and may void the servovalve warranty. MTS does not recommend changing the 35-micron filter element in the Series 252.2x/.4x Servovalve (revision C).
Procedure To replace the filter element, perform the following procedure. Care should be exercised to prevent dirt or other contaminants from entering the servovalve body, filter passages, or manifold/actuator ports. Refer to the following figure during the procedure. Socket Head Screws (4) 1 3 4 Filter Cover Plate 2 Filter Plug Filter Plug O-Rings Filter O-Ring Filter Filter Cover Filter Housing Model 252.2x/.4x Filter Location Model 252.3x Filter Assembly (Revision G only) 10.
D. Lightly lubricate the filter with clean hydraulic fluid and insert the filter into the housing. E. Secure the filter cover plate to the housing using the four socket head screws and washers removed in Step A. For the Series 252.3x Servovalve proceed as follows: A. Remove the four socket head screws and washers that secure the filter cover plate to the filter housing as shown below. B.
During the servovalve mechanical null adjustment procedure, the actuator must be able to move through full displacement in either direction without contacting a reaction surface. Valve balance adjustments MTS controllers have an electronic mechanical null adjustment called valve balance. The valve balance adjustment is a convenient way to compensate for a servovalve that needs a mechanical null adjustment.
CAUTION Excessive torquing may shear off the adjustor pin eccentric. Do not apply more than 12 lbf-in. (1.36 N•m) of torquing force to the adjustor pin. If the pin does not turn using very little force, proceed to Step C of this task. 92 Maintenance B. Slowly rotate the adjustor pin until the actuator movement is reduced to a minimum, and then go back to Step 2. If the pin does not turn using very little force, proceed to the next step. C.
G. Using the offset wrench, loosen (but do not remove) the self-locking nut. Mechanical Null Adjustor Pin H. Turn the adjustor pin until the scribe mark on the adjustor pin is pointing toward the base of the servovalve. I. Tighten the self-locking nut until 1.13 to 1.36 N·m (10 to 12 lb-in) of torque is needed to turn the adjustor pin, ensuring that the scribe mark remains pointing toward the base of the servovalve. J. Remove the torque wrench and offset wrench. 4. Finish the procedure.
Maintenance Series 322 Load Unit
m MTS Systems Corporation 14000 Technology Drive Eden Prairie, Minnesota 55344-2290 USA Toll Free Phone: 800-328-2255 (within the U.S. or Canada) Phone: 952-937-4000 (outside the U.S. or Canada) Fax: 952-937-4515 E-mail: info@mts.com Internet: www.mts.
