Hydraulic QDC Clamps

Hydraulic Cylinder Style Nut Clamps

Use Nut Clamps with dies having slotted die plates or U-Slot brackets.

Use Nut Clamps with dies having slotted die plates or U-Slot brackets.

When to Use Nut Clamps:

nut-clamps-pg4-graphic2Use Nut Clamps with dies having slotted die plates and enough clearance for the Nut Clamp body (see chart). U-Slot brackets or ears may also be added to dies in some applications.

If systems are setup to have hydraulics removed during stamping, Hydra Mechanical (L style) clamps (with a mechanical lock) should be selected. If a dedicated hydraulic system is considered, the Fully Hydraulic clamps (with either multiple upper zone control or check valves) may be the preferred choice.

Clamp model and quantity should be selected to provide a total clamping force greater than the total (static and dynamic) force applied to the system during use.

 

How They Work:

nut-clamps-pg4-graphic3Nut Clamps are moved into position in a slot in the die plate (gaps between clamp and die/slot allow movement). When hydraulic pressure is applied, the clamp pulls upward on the T-bolt and the clamp body moves downward to clamp the plate. Hydraulic pressure is maintained during operation, or the Locking Nut (L style) is engaged to allow removal of clamp hydraulic pressure during stamping. To unclamp, hydraulic pressure is removed and clamps open under internal spring force. (Note: Reapplication of hydraulics is required to unlock the Locking Clamps (L) prior to releasing pressure and unclamping).

Applications/Sizing

The Hydraulic Nut Clamps cover three basic sizes based on clamp force,  Model 205 at 8,000 lbf, Model 200 at 10,000 lbf, and Model 201 at 15,000 lbf.  The “Locked” designation (L) is added to the model number for the Locking screw that can be used to secure the clamp in position so Hydraulics can be removed during stamping.  Locking clamps are commonly referred to as Hydra-Mechanical Clamps (HM) as they are hydraulically clamped and mechanically locked.

After selecting the model and Locking if desired, the clamp part number is built up based on the model number and then the clamping plate height or clamp height (CLH) and T-slot size.  The clamping height is sized in ¼” increments for the small clamp heights and ½” increments above 2.00”.  Note that these types of clamps are designed to clamp on a plate when close to the clamp plate.  For varying clamp plate heights the clamp must be threaded up or down the threaded stud to achieve the starting clamp position close to the clamp plate and snug in the T-slot prior to clamping.

Fundamentally these clamps should not be adjusted in height without careful consideration of proper thread engagement in the Nut clamp and adequate stroke of the clamp to take up gaps between components.  See the specific Nut Clamp User Guide and/or Specification Drawing for details on recommended gaps and heights.

For selecting the appropriate components to achieve catalog clamping height (CLH), PFA assumes standard JIC T-Slot dimensions to fit the T-Slot and typically Neck height is assumed as .750” for 5/8” slot, .875” for 3/4” slot, 1.000” for 1” slot.

Standard Configurations
QDC hollow cylinder nut clamp part dimensional information PFA SMED
Model 200/200LModel 201/201LModel 205/205L
Bolster/Ram InterfaceT-Slot ¾” or 1”Threaded Hole (TH)T-Slot 1” onlyT-Slot ⅝”, ¾” or 1”Threaded Hole (TH)
Clamping Force at 5,000 PSI10,000 lbs.15,000 lbs.8,000 lbs.
Clamping Stroke.29”.60”.25”
Standard Thread Size¾” – 10Hole Size*** ⅝” – 11×1.85 minimum1” – 8⅝” – 11Hole Size*** ½” – 13×1.85 minimum
A2.50”3.12”2.00”
BFull Hydraulic (without lock)2.20”3.00”3.50”2.00”2.65”
Hydra Mechanical (L) (with lock)3.20”4.00”4.90”3.00”3.65”
D**CLH*
.50”
.75”
1.00”
1.25”
1.50”
1.75”
2.00”
2.50”
**
No Lock
3.50”
3.50”
4.00”
4.00”
4.50”
4.50”
5.00”
5.50”
**
Lock (L)
4.00”
4.25”
4.50”
4.75”
5.00”
5.25”
5.50”
6.00”
**
No Lock
3.50”
3.75”
4.00”
4.25”
4.50”
4.75”
5.00”
5.50”
**
Lock (L)
4.50”
4.75”
5.00”
5.25”
5.50”
5.75”
6.00”
6.50”
**
No Lock
4.00”
4.25”
4.50”
4.75”
5.00”
5.25”
5.45”
5.95”
**
Lock (L)
6.00”
6.25”
6.50”
6.75”
7.00”
7.25”
7.50”
8.00”
**
No Lock
3.25”
3.25”
3.75”
3.75”
4.25”
4.25”
4.75”
5.25”
**
Lock (L)
3.75”
4.00”
4.25”
4.50”
4.75”
5.00”
5.25”
5.75”
**
No Lock
3.15”
3.40”
3.65”
3.90”
4.15”
4.40”
4.65”
5.15”
**
Lock (L)
4.15”
4.40”
4.65”
4.90”
5.15”
5.40”
5.65”
6.15”
**
Weight3.0 lbs.5.0 lbs.8.5 lbs.2.0 lbs.3.0 lbs.
nut-clamp-chart-image-1nut-clamp-chart-image-2nut-clamp-chart-image-3nut-clamp-chart-image-4nut-clamp-chart-image-5nut-clamp-chart-image-6nut-clamp-chart-image-7nut-clamp-chart-image-8nut-clamp-chart-image-9nut-clamp-chart-image-10

*Clamp Height (CLH) based on standard JIC T-Slot dimensions. T-Slot dimensions are typically: (Neck height is .750” for 5/8” slot, .875” for 3/4” slot, 1.000” for 1” slot).

**D=Product height installed is related to clamp height needed for clamp plate thickness. Stock sizes listed, but others are easily available. Dimension is worst case based on the smallest slot neck height and includes 1/4” clearance for slot variation.

***For TH models, threaded rod will engage bolster 1.3” minimum and range from 1.35” to 1.75” typical. If application is unique, call PFA for assistance.

Identify Your Part Number

Example: 13,000 lb. die typically uses a 15,000 lb. clamp such as Model 201. Clamp plate thickness (CLH) is 1.0”. 1” T-Slot.

QDC hollow cylinder nut clamp part number specification PFA SMED

View/Download User Guides:

Hydraulic, Fixed Clamp Height, Rocker Style Ledge Clamps

Hydraulic Ledge Clamps

Use Ledge Clamps (Fixed Clamp Height Rocker Clamps) with dies having a clamp plate that sticks out from the die body or has a large slot.

Use Ledge Clamps (Fixed Clamp Height Rocker Clamps) with dies having a clamp plate that sticks out from the die body or has a large slot.

When to Use Fixed Clamp Height Rocker Clamps

Ledge-ClampsUse Fixed Clamp Height Rocker Clamps with dies having an open ledge clamp plate or a slot in the die large enough to accommodate the clamp nose for full clamp engagement. Ledge brackets, bars, or ears may also be added to dies in some applications to accommodate the clamps and/or plates milled to set a common clamp height.

If systems are setup to have hydraulics removed during stamping, Hydra Mechanical (L style) clamps (with a mechanical lock) should be selected. If a dedicated hydraulic system is considered, the Fully Hydraulic clamps (with either multiple upper zone control or check valves) may be the preferred choice.

Clamp model and quantity should be selected to provide a total clamping force greater than the total (static and dynamic) force applied to the system during use.

How They Work:

Ledge-Clamps2Ledge Clamps are moved into position with the lower body stop set against the die plate (gaps between clamp and die/slot allow movement) or may be permanently mounted on one side to act as a side stop.

When hydraulic pressure is applied, the clamp nose moves downward onto the plate, clamping the die. Hydraulic pressure is maintained during operation, or the Locking Nut (L style) is engaged to allow removal of clamp hydraulic pressure during stamping. To unclamp, hydraulic pressure is removed and clamps open under internal spring force. (Note: Reapplication of hydraulics is required to unlock the Locking Clamps (L) prior to releasing pressure and unclamping).

Applications/Sizing

Hydraulic Ledge Clamps are separated into single clamps and double clamps with the single clamps taking up a single T-slot (Models 425 and 428) and double clamps taking up two slots (Models 126 and 128).   Double clamps provide for significant force at 22,000 lbf and 26,000 lbf respectively, however distance between slots is specifically 12 inches and cannot be changed.  For large retrofit applications and medium force applications is it typical to use multiples of the single T-slot clamps Model 425 at 8,000 lbf clamp force and Model 428 at 10,000 lbf clamp force.

The “Locked” designation (L) is added to the model number for the Locking screw that can be used to secure the clamp in position so Hydraulics can be removed during stamping.  Locking clamps are commonly referred to as Hydra-Mechanical Clamps (HM) as they are hydraulically clamped and mechanically locked.  Units are also available with a handle to make moving the clamps easy for operators.

After selecting the model and Locking/Handle options, the clamp part number is built up based on the model number and then the clamping plate height or clamp height (CLH) and T-slot size.  The clamping height is sized in ¼” increments for the small clamp heights and ½” increments above 2.00”.  Note that these types of clamps are designed to clamp on a plate height that is fairly consistent as the clamping stroke of the clamp is designed to accommodate variations in T-slot to T-Nut gap and some gap to slide the clamp into position.  Fundamentally these are not adjustable clamp height clamps.  See Nut Clamps or Adjustable Rocker Clamps for clamps designed to accommodate moderate variations in clamp plate thickness.

For selecting the appropriate components to achieve catalog clamping height (CLH), PFA assumes standard JIC T-Slot dimensions to fit the T-Slot and typically Neck height is assumed as .750” for 5/8” slot, .875” for 3/4” slot, 1.000” for 1” slot).  See the specific Rocker Clamp User Guideand/or Specification Drawing for details on recommended gaps and heights.

Standard Configurations
QDC fixed height ledger rocker clamp dimensional information PFA SMED
Model 425Model 425LModel 428Model 428LModel 126Model 126LModel 128Model 128L
Clamping Force at 5,000 PSI8,000 lbs.10,000 lbs.22,000 lbs.26,000 lbs.
T-Nut SpacingN/AN/A6”6”
A4.25” no handle
4.50” with handle
4.25” no handle
4.50” with handle
12”12”
B**CLH*
.50”
.75”
1.00”
1.25”
1.50”
1.75”
2.00”
2.50”
**
No Lock
2.75”
2.75”
2.75”
3.00”
3.25”
3.50”
3.75”
4.25”
**
Lock (L)
4.25”
4.25”
4.25”
4.50”
4.75”
5.00”
5.25”
5.75”
**
No Lock
3.75”
3.75”
3.75”
3.75”
4.00”
4.25”
4.50”
5.00”
**
Lock (L)
4.25”
4.25”
4.25”
4.25”
4.50”
4.75”
5.00”
5.50”
**
No Lock
2.75”
2.75”
2.75”
3.00”
3.25”
3.50”
3.75”
4.25”
**
Lock (L)
4.25”
4.25”
4.25”
4.50”
4.75”
5.00”
5.25”
5.75”
**
No Lock
3.75”
3.75”
3.75”
3.75”
4.00”
4.25”
4.50”
5.00”
**
Lock (L)
4.25”
4.25”
4.25”
4.25”
4.50”
4.75”
5.00”
5.50”
**
CJaw Opening to Match CLH* + .18” gapJaw Opening to Match CLH* + .18” gapJaw Opening to Match CLH* + .18” gapJaw Opening to Match CLH* + .18” gap
D4.00” no handle
7.25” with handle
4.75” no handle
7.25” with handle
4.00” no handle
7.25” with handle
4.75” no handle
7.25” with handle
E.88” Max.1.14” Max..83” Max1.12” Max.
Weight (approx.)8 lbs.12 lbs.25 lbs.35 lbs.
ledge-clamp-chart-image-1ledge-clamp-chart-image-2ledge-clamp-chart-image-3ledge-clamp-chart-image-4ledge-clamp-chart-image-5ledge-clamp-chart-image-6ledge-clamp-chart-image-7ledge-clamp-chart-image-8

*CLH= Clamping height – Nominal Clamp Plate Thickness based on clamping plate being within 0.030” of nominal. Clamp plate may be thicker than CLH as desired but less than the 0.18” total gap available. Clamps are provided with “C” open dimension, which is the CLH + 0.18” gap to allow for an option of .090” die lifter rail clearance and .060”-.090” air clearance for moving clamp in and out of position – allows lifting and moving dies under open clamps if necessary. Difference between C dimension and Actual Clamping Height should not exceed 0.18” which is 1/2 of the 0.36” total stroke of the clamp. Clamping height is also based on standard JIC T-Slot dimensions for T-nut sizing. T-Slot dimensions are typically neck height .875” for 3/4” slot and 1.00” for 1” slot.

** B = Product Height Dimension is related to clamp height needed for clamp plate thickness. Stock sizes listed, but others are easily available. Allow 1/2” more for nominal variations.

***Handles (H) available on all models. Contact PFA for details.

Identify Your Part Number

Example: 8,000 lb. die. Use 8,000 clamp such as Model 425, clamp plate thickness (CLH) is 1.0” and has 3/4 T-Slot.
Locking (L) and Handle (H) are added directly after the main model number. Examples are 425, 425L, 425H and 425LH.

QDC fixed height ledger rocker clamp part number specification PFA SMED

View/Download User Guides:

Hydraulic "Ledge Like" and Narrow Style Adjustable Rocker Clamps

Use Adjustable Rocker Clamps with dies having a cutout clamp position, narrow slot, extended clamp plate and/or variable clamp plate thickness.

Use Adjustable Rocker Clamps with dies having a cutout clamp position, narrow slot, extended clamp plate and/or variable clamp plate thickness.

When to Use Adjustable Rocker Clamps:

Use Adjustable Rocker Clamps with dies having a cutout clamp position, narrow slot in the die or for typical clamp plate applications with variable clamp plate thickness across several dies. Also, ledge brackets, blocks, bars, or ears may be added to dies in some applications to accommodate the clamps and/or small slots cut into the dies to accept the smaller clamp nose.

If systems are setup to have hydraulics removed during stamping, Hydra Mechanical (L style) clamps (with a mechanical lock) should be selected. If a dedicated hydraulic system is considered, the Fully Hydraulic clamps (with either multiple upper zone control or check valves) may be the preferred choice.

Clamp model and quantity should be selected to provide a total clamping force greater than the total (static and dynamic) force applied to the system during use.

How They Work:

The Adjustable Rocker Clamps are moved into position with the lower body stop set against the die plate (gaps between clamp and die/slot allow movement).

The center height adjustment knob is turned clockwise until the nose of the clamp touches the clamp plate.

When hydraulic pressure is applied, the clamp nose moves downward onto the plate, clamping the die. Hydraulic pressure is maintained during operation, or the Locking Nut (L style) is engaged to allow removal of clamp hydraulic pressure during stamping. To unclamp, hydraulic pressure is removed and clamps open under internal spring force. (Note: Reapplication of hydraulics is required to unlock the Locking Clamps (L) prior to releasing pressure and unclamping). After the clamp is released, the adjustment knob is turned to further open the clamp, as desired.

Applications/Sizing

Standard Configurations
QDC adjustable rocker clamp standard configurations 835 image PFA SMED
Model 661    /    Model 661LModel 825    /    Model 825LModel 835    /    Model 835L
Clamping Force at 5,000 PSI3,500 lbs.8,000 lbs.17,000 lbs.
Stud Thread Size⅝” – 11¾” – 101” – 8
T-Nut/Slot Style¾” or 1”¾” or 1”1”
A5.25”7.5”9.6”
B1.75”2.50”4.00”
C**CLH*
1.0
2.0
3.0
*
Nominal Clamping Range
¾” – 1¼”
1¾” – 2¼”
2¾” – 3¼”
*
Nominal Clamping Range
⅞” – 1¾”
1⅞” – 2¾”
2⅞” – 3¾”
*
Nominal Clamping Range

1¼” – 2½”
2¼” – 3½”
*
D**CLH*
1.0
2.0
3.0

3.75”
4.75”
5.75”

4.75”
5.75”
6.75”

6.00”
7.00”
8.00”
E (Nose Over Plate).75”.87”1.00”
F (Width at Plate)1.10”2.00”2.60”
Weight (approx.)5 lbs.13 lbs.32 lbs.
rocker-clamps-chart-image-1rocker-clamps-chart-image-2rocker-clamps-chart-image-3

t-slot-bolt

*Nominal clamp height for part number selection. Actual clamp range for selected unit listed in chart. Customs available.

C** and D**= Product clamping range and height dimension is related to nominal Clamping Plate Thickness (CLH) chosen. Allow 1” height clearance for nominal variations and actuation.

Clamps are provided with T-Slot Bolt (A) or Fully Threaded Stud and T-Nut (B), depending on availability.

Identify Your Part Number

Example:  6,000 lb. die.  Use 8,000 clamps such as Model 825L, clamp plate thickness (CLH) is 1.0” and has 3/4 T-Slot.

QDC Adjustable Rocker Ledge Clamp for SMED part number specification

View/Download User Guides:

Hydraulic, Fixed Clamp Height, Sliding Style C-Clamp

PFA_082808_03

Hydraulic, Fixed Clamp Height, Sliding Style C Clamp

“C” Clamps work in similar applications to our fixed height ledge clamps, but provided a different profile and customer preference. Using small Bolt-on guides, these clamps also work well in “slotless” press applications (bolsters with threaded holes only). Also, by reaching under and over the clamping plate and providing multiple ports, the clamp can be set “deeper” over the plate if needed, resulting in a lower installed profile.

Available in the single piston style Model 283 and double piston style Model 283D, “C” clamps require only 1.25″ to 1″ of die plate engagement, respectively, and may be modified at the nose to engage plates that have been pocketed to match clamp heights. Ledge brackets, bars, or ears may also be added to dies in some applications to accommodate the clamps. Clamp model and quantity should be selected to provide a total clamping force greater than the total (static and dynamic) force applied to the system during use.

Clamp sizing is done to provide a minimum .060″ clearance to the clamp plate and accommodate a wide range of slot neck height and clamp plate height combinations. For a given T-slot neck depth (N) and clamping plate height (CLH) the needed part number can be easily determined.

Applications/Sizing

Standard Configurations
PFA C Clamp Hydraulic QDC SMED how to size
Model 283Model 283D
Clamp Force at 5,000 PSI6,700 lbs6,900 lbs.

 

Clamp Height CLHSlot Neck Depth (N) Range
.50”-.75”.75”-1.00”1.00”-1.25”.25”-1.50
¾”-50-75-100-125
1”-75-100-125-150
1¼”-100-125-150-175
1½”-125-150-175-200
1¾”-150-175-200-225
2”-175-200-225-250
**

*For a given N and CLH find the correct Dash No. or use H values (exact total clamp opening).
**Other sizes available. Please call PFA for details.

 

Dash No.H*
-501.560”
-751.810”
-1002.060”
-1252.310”
-1502.560”
-1752.810”
-2003.060”
-2253.310”
-2503.560
**

Identify Your Part Number

Example:  Application requires clamps with 6,000 lbs. clamp force.  T-slot is 3/4 and has a neck (throat) depth of .875”.  Clamp height (CLH) = 1”.  Enter top of chart with Neck Depth of .875” (.750-1.00) and side of chart with CLH value (1”) to obtain (-100) with an “H” value of 2.06”

PFA C Clamp Hydraulic QDC SMED specifications for Part number
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