Harford Attachments Pro-lok User manual

DOUBLE-LOCKING
MECHANICAL QUICK HITCH
Installation & Operation Manual (English)
Important: This manual should be kept with the excavator at all times
for easy reference.

2 ©2022 Harford Attachments Ltd
PROLOK/GEN/MAN/R4
Table of Contents
Contents
Item Checklist ..................................................................................................................................3
Introduction......................................................................................................................................4
Safety Features.................................................................................................................................4
Guide to Safety Symbols..................................................................................................................5
General Safety Information..............................................................................................................5
Safety labels .....................................................................................................................................6
Safety Sticker and Data Plate Location Guide.................................................................................7
Specified Parameters........................................................................................................................7
Storage Instructions..........................................................................................................................7
End of Life Considerations ..............................................................................................................8
Compatible Attachments..................................................................................................................8
Fitting the Harford Pro-Lok to your Excavator................................................................................9
Connecting an Attachment to your Pro-Lok..................................................................................10
Releasing an Attachment................................................................................................................12
Lifting a Load.................................................................................................................................12
Important Maintenance Information ..............................................................................................14
Routine Maintenance Information .................................................................................................15
Warranty.........................................................................................................................................16
Example Declaration...................................................................... Error! Bookmark not defined.
Serial Number Location
Serial Number
Stamped plate on side of hitch
Sticker on rear of control box
Sticker on solenoid manifold
Serial number table (above) for completion by owner
This manual part number PROLOK/GEN/MAN/R4
If this Pro-Lok quick hitch to is to be used on a jobsite, the operator shall follow the site rules where the
machine is to be used.
If at any time in the future, you require additional information on the
HARFORD PRO-LOK quick hitch or any aspects of its use, please do not hesitate to contact:
Harford Attachments Ltd
Spar Road, Norwich. NR6 6BY. England
Tel [phone]
email: [email protected]m website: www.harfordattachments.com

©2022 Harford Attachments Ltd 3
PROLOK/GEN/MAN/R4
Item Checklist
The following items are supplied with the Harford Pro-Lok.
Item
Supplied
Mechanical quick hitch
✓
CE Declaration of Conformity
✓
Ratchet
✓
Installation and operation manual
✓
Safety pin not required stickers
✓
Warning label
✓
Lifting eye test certificate
see note
Note: The lifting eye test certificate is only supplied if a lifting eye is fitted to the Pro-Lok during
manufacture.

4 ©2022 Harford
Attachments Ltd PROLOK/G
EN/MAN/R4
Introduction
Thank you for purchasing the Harford Pro-Lok quick hitch for excavators. The
information contained in this manual should be read carefully and understood by all
operators of the quick hitch, to ensure optimum performance of the product.
The Harford Pro-Lok is designed to pick up standard attachments for excavators,
made to OEM specification. The adjustable sliding wedge plate provides a locking
device, which is free from movement. This minimises any wear over the lifetime of the
hitch.
There are several unique safety features are built-in to the Pro-Lok. The combination
of which results in a safe, tough and durable product. Regular maintenance of the hitch
will give you many hours of reliable, trouble-free operation.
It is important that the installation is carried out by a competent person, preferably
someone with experience of quick hitch operation.
The operation and maintenance instructions should be followed carefully to ensure safe
and correct use of the quick hitch. Failure to do so could cause injury and/or invalidate
the product warranty.
IMPORTANT:
All Harford Pro-Lok hitches are CE certified, having undergone a thorough
evaluation process by Harford Attachments. Any subsequent modification to the
hitch will invalidate this certification and the product warranty.
Safety Features
There are several unique safety features incorporated into the Harford Pro-Lok quick
hitch. The features combine to prevent attachments becoming unintentionally
disengaged from the quick hitch.
1. The wedge plate is tightened the same way as a bolt, i.e., in a clockwise direction.
2. A patented anti-unwind feature is built into the threaded actuator. This can easily
be adjusted to ensure firm rotation during maintenance.
3. The geometry of the wedge plate and quick hitch locking surface creates a locking
mechanism in its own right. The clamping force of the wedge surface is up to 4.5
times the force applied by the threaded actuator. This feature creates a secure and
safe locking device.
4. A sprung loaded front lock ensures that the front pin is secure when connecting an
attachment and during operation. This is visible to the operator from the cab.
5. A rear lock indicator allows the operator to check that the rear locking wedge is in
its correct operating position. This is also visible from the cab.

©2022 Harford Attachments Ltd 5
PROLOK/GEN/MAN/R4
Guide to Safety Symbols
SAFETY NOTICE:
These indicate specific precautions and recommended personal protective
equipment (PPE) for use during the given situations.
IMPORTANT:
Specific points to note and situations to be aware of.
IMPORTANT:
Prohibited situations are specified and should be avoided.
WARNING:
Situations of danger in which the operator or installer must pay particular
attention to the information provided to minimise the risk of injury to self or
others
General Safety Information
IMPORTANT:
Due to the weight of the product, handling of the hitch prior to installation should be
done using appropriate lifting aids for the weight, which can be found on the punched
information plate affixed to the side of the hitch.
IMPORTANT:
Ensures that the machine to which the Pro-Lok quick hitch is installed does not
exceed its safe working load (SWL), taking into account the additional weight of the
hitch, which is stated on the punched information plate affixed to the side of the hitch.
IMPORTANT:
Be aware that the addition of the Pro-Lok quick hitch will increase the reach distance
of the excavator arm, which may cause it to impact nearby objects and people or to
impact the operators cab, leading potentially to property damage, injury, loss of limb
or fatal injury.
IMPORTANT:
It is recommended for safety reasons that the machine to which this Pro-Lok quick
hitch is installed is operated by an experienced, competent person, trained to ISO
7130:2013 or later.
IMPORTANT:
If hammers are to be used for long periods of time the quick hitch should be removed
to prevent unnecessary wear.
IMPORTANT:
During installation, no alterations must be undertaken to any protective structure
(e.g., rollover protective structures (ROPS), tip-over protective structures (TOPS), or
falling object protective structures (FOPS) are permitted except where authorised by
the manufacturer, or according to the manufacturer’s specifications.

6 ©2022 Harford
Attachments Ltd PROLOK/G
EN/MAN/R4
IMPORTANT:
It is not permitted to transport or lift persons using the Pro-Lok quick hitch.
Safety labels
All safety labels are to be kept clean and legible and should be replaced if missing or
unreadable by contacting the manufacturer, Harford Attachments, on [phone].
The following safety label is supplied in the required quantities with the Pro-Lok fitting kit.
Their locations are given in the description, and shown graphically in the following diagram.
A) One yellow warning sticker to be affixed prominently in the cab warning that the
attachment increases the overall length of the dipper arm and could therefore impact
the cab or boom if care is not taken:

©2022 Harford Attachments Ltd 7
PROLOK/GEN/MAN/R4
Safety Sticker and Data Plate Location Guide
Specified Parameters
Your Harford Pro-Lok quick hitch has been designed to the meet the original equipment
manufacturer (OEM) specifications of the excavator for which it was ordered. The excavator
model for which it was designed and the maximum load category of the hitch can be found on
the punched information plate affixed to the side of the quick hitch body.
Storage Instructions
If your Pro-Lok Quick hitch is to be removed for an extended period of time, please observe
the following instructions:
SAFETY NOTICE:
It is strongly recommended that the Pro-Lok quick hitch is lowered to the ground, the
machine switched off, the key removed and the parking brake engaged, blocks applied to
the wheels, the system depressurised and that safety gloves are worn during any
maintenance on the quick hitch. A warning label should be affixed prominently in the cab
to warn others of ongoing maintenance.
•Wearing appropriate PPE, hydraulic fluid should be drained from the quick hitch and
disposed of according to regulations.
•Basic maintenance tasks should be carried out on the hitch, including cleaning and
greasing (see the Daily Checks list for further information).
•The hitch should be covered and stored in a safe, dry location.
1 of A
Pro-Lok
quick hitch
Lifting Eye
(if installed)
Location of
data plate

8 ©2022 Harford
Attachments Ltd PROLOK/G
EN/MAN/R4
End of Life Considerations
Your Pro-Lok quick hitch is predominantly made of recyclable materials. If your quick hitch
should become damaged beyond repair and is to be disposed of, please be aware of the
environmentally unfriendly nature of the lubricants and hydraulic fluids used. Please check the
cleaning and disposal instructions of the supplier of the contaminants before disposing of the
hitch in an environmentally responsible manner.
Compatible Attachments
Attachment
Can be used (up to
the safe working load)
Can be used, with
limitations
Cannot be used
All Harford
Attachments

Buckets

Hammer or breaker
For limited periods.
For constant or long-
term use, the Pro-Lok
hitch should be
removed to prevent
unnecessary wear
Pallet forks
Under no
circumstances
Lifting Objects with
hitch
Only if a factory fitted
lifting eye was
supplied with the hitch,
certified to the SWL.
Operator cages
Under no
circumstances
Thumb

Ripper Tooth

Rake

IMPORTANT:
Attachments should be within the recommended limits of the carrying machine when
the quick coupler is attached

©2022 Harford Attachments Ltd 9
PROLOK/GEN/MAN/R4
Fitting the Harford Pro-Lok to your Excavator
SAFETY NOTICE:
It is recommended that safety gloves are worn during the installation of the
quick hitch.
1. Remove any existing attachment from the machine dipper arm and crowd link arm.
The two original pins that areremoved fromthese pivot points must be used toattach
the Pro-Lok hitch to the excavator (These pins are usually hardened and
greaseable).
2. Carefully align the dipper arm between the two front bosses on the hitch as shown
in Figure 1. Replace any ‘O’rings that were removed previously and slide one of
the original pins throughthe quick hitch and dipper arm. Securely fix the pin in place
by using the original or supplied retention method. Ensure any retention bolts are
tightened using double nuts to lock against each other.
3. Repeat step 2 with the crowd link arm linkage.
4. Grease the two pins and visually checkthat they are located and secured correctly.
5. Use the excavator hydraulics to carefully rotate the quick hitch to the extremes of
the crowd cylinder (e.g., no stroke and full stroke). Check the clearance of the quick
hitch with any part of the dipper arm and linkage.
6. Fit the supplied yellow Warning sticker in the cab in a prominent position. Also
supplied are three ‘Safety Pin Not Required’ stickers –one to fit in the cab
alongside the yellow Warning sticker and one each side of the dipper arm near the
quick hitch.
7. Medium tensile pins (or better) should be used in both pin location holes of the
attachment. Visually check to ensure the pins are correctly fitted and are secure
before the attachment is used. Ensure any retention bolts are tightened using
double nuts to lock against each other.
8. You can now proceed to ‘Connecting an Attachment to your Pro-Lok’.
Crowd Cylinder
Idler Link
Crowd Link
Pro-Lok
Original Pins
Dipper Arm
Figure 1

10 ©2022 Harford Attachments Ltd
PROLOK/GEN/MAN/R4
Connecting an Attachment to your Pro-Lok
SAFETY NOTICE:
It is recommended that safety gloves are worn during the attachment changeover
operation.
1. Lower the quick hitch front C-shaped jaw down towards the front attachment pin, as shown
in Figure 2, step 1.
2. Engage C-shaped jaw with front attachment pin as shown in Figure 2, step 2.
3. Extend the crowd cylinder down towards the rear attachment pin whilst simultaneously lifting
the attachment, as shown Figure 2, step 3.
4. Continue extending the crowd cylinder so the front attachment pin is firmly seated in the C-
shaped jaw and the rear pin is seated on the rear locking surface, shown in Figure 2, step 4.
5. Use the ratchet spanner to rotate the threaded actuator in a clockwise direction until the
wedge plate is fully tightened against the rear attachment pin.
6. Visually check that the locking wedge plate is securely located against the rear attachment
pin and the front lock is closed. Also ensure that the indicator bar is in the correct operating
position as shown by Figure 3.
Figure 2
Step 2 –Engage ‘C’ shaped
jaw with front attachment pin
Step 3 –Crowd quick hitch to
engage with rear attachment pin
Step 4 –Crowd bucket until rear pin
is much lower than attachment pin
Front bucket pin
Rear bucket pin
Step 1 –Lower quick hitch to
front attachment pin

Figure 3: Correct operating position
Figure 4: Incorrect operating position
Figure 5: Releasing an attachment position

12 ©2022 Harford Attachments Ltd
PROLOK/GEN/MAN/R4
WARNING:
During operation there should be no movement between the Pro-Lok hitch and any attachment.
If movement is detected, stop operation immediately, lower the attachment to the ground and
inspect the hitch.
WARNING:
The Pro-Lok extends the length of the dipper arm and some attachments may hit the cab or
boom in certain positions as a result.
WARNING:
The Pro-Lok is designed to pick up attachments manufactured to OEM specifications and
capacities only. Use of oversized attachments with this quick hitch can be hazardous and may
invalidate the product warranty should damage occur.
WARNING:
Ensure the Safe Working Load of the excavator is not exceeded - check the excavator
manufacturer’s information.
IMPORTANT:
To prevent unnecessary wear and tear, we recommend that the Pro-Lok hitch is removed if
hydraulic hammers are to be used on the excavator for long periods of time.
IMPORTANT:
The use of pallet forks with the Pro-Lok is not recommended, in order to maintain the integrity of
the product design. Mis-use, resulting in damage to the hitch could invalidate the product
warranty.
Releasing an Attachment
1. When releasing an attachment, first ensure people and property are well clear of the area of
operation. Place the attachment on level ground or in a position so that once released the attachment
cannot roll away from the hitch.
2. Use the ratchet spanner to rotate the threaded actuator in an anti-clockwise direction until the rear
wedge plate is fully retracted and front lock fully open as shown in Diagram 5.
3. Using the crowd cylinder of the excavator, rotate the quick hitch away from the rear pin of the
attachment then lift away from the front attachment pin.
Lifting a Load
IMPORTANT:
This section only applies to quick hitches that are supplied with a factory fitted and certified lifting
eye.
WARNING:
If your Pro-Lok hitch was not supplied with a factory fitted and certified lifting eye you must not
attempt to lift loads that are not wholly contained within a bucket-type attachment, it is unsafe,
may lead to damage and will invalidate the warranty.
IMPORTANT:
Ensure the safe lifting capacity of the excavator is not exceeded. Refer to excavator
manufacturer’s information.
1. Ensure that the load to be lifted does not exceed the safe working load of the lifting eye.
2. The lifting eye is designed to be used with a lifting shackle with the same safe working load rating.

3. Release the attachment from the quick hitch prior to using it to lift load.
If your Pro-Lok hitch was supplied with a factory-fitted lifting eye, it must be examined at regular
intervals for damage and defects, by a competent person, in accordance with UK HSE LOLER 1998
guidelines, which can be found at www.hse.gov.uk.

14 ©2022 Harford Attachments Ltd
SAFELOCK/GEN/MAN/R5
Figure 6: Typical thread actuator assembly
Important Maintenance Information
Adjusting the Threaded Actuator
The rotational resistanceof the threaded actuator must be firm at all times but can be easily adjusted
using standard tools. This safety feature further enhances the positive locking mechanism built into
the Harford Pro-Lok hitch.
1. Disconnect the attachment from the Harford Pro-Lok.
2. Remove the wedge plate from the Pro-Lok by rotating the threaded actuator in a clockwise
direction until the two parts disconnect.
3. Remove the two bolts, retaining the protective shroud over the threaded actuator. Slide the
shroud off the threaded shaft and remove completely.
4. Using an Allen key, loosen the cap screws in the split nut.
5. Place the ratchet spanner in the square drive and rotate the split nut anti-clockwise (L.H. thread)
until it tightens up firmly against the thrust washers.
6. Clamp the split nut against the threaded shaft by tightening up the cap screws.
7. Check the tightness of the threaded actuator. It should only be possible to rotate the actuator
with the ratchet spanner, not by hand.
8. Re-assemble and grease, see Routine Maintenance Information on page 8, steps 3 and 4.
WARNING:
Ensure wedge plate is fully retracted before greasing.
ITEM
DESCRIPTION
1
L.H. Thread
2
2 x DU Washer
3
DU Bush
4
2 x Hex. Head Bolt
5
Front Plate
6
2 x Cap Screw
7
L.H. Split Nut
8
Shroud
9
2 x Grease Nipple
10
Shroud Seal
11
2 x Spring Washer
12
2 x Hex. Nut
13
Pan Head Screw
14
Red Sleeve
15
Wedge Assembly

Routine Maintenance Information
SAFETY NOTICE:
It is strongly recommended that the Pro-Lok quick hitch is lowered to the ground, themachine
switched off and the ignition key removed, the parking brake engaged and blocks applied to
the wheels, that the system depressurised and safety gloves are worn during any
maintenance on the quick hitch. A warning label should be affixed prominently in the cab to
warn others of ongoing maintenance.
Daily Checks:
Daily checks are to be carried out before the use of the Pro-Lok quick coupler; the operator shall
have sufficient competence and training to perform the maintenance. During these checks, should
any faults that could compromise safety be identified they should be remedied immediately.
1. Clean away any material build up around the front lock, indicator bar and wedge.
2. Check all pin retaining bolts and nuts for tightness on the quick hitch and attachments.
3. Grease wedge slide housing points as required. It is necessary to remove attachments in order
to gain access to a grease nipple on the underside of the hitch.
4. Grease threaded actuator points, as required.
WARNING:
Ensure wedge plate is fully retracted before greasing.
5. Check the Pro-Lok for correct operation by connecting an attachment.
6. Check that the threaded actuator is firm to rotate in its housing. Adjust as required, see
“Adjusting the Threaded Actuator” on page 7.
7. Visually check the Pro-Lok for evidence of fatigue, weld failure or stress.
IMPORTANT:
Due to the self-tightening and infinite wear feature accommodated with the wedge lock, if any
attachment is fitted to the hitch for long periods of time it should be released daily. If the daily
maintenance tasks are adhered to, this will happen automatically.
WARNING:
If the quick hitch is damaged in any way and/or there is any doubt as to the continued safety, cease
operation immediately and contact Harford Attachments Ltd, Technical Department on Europe: +44
(0)1603 403099, USA: 727 477 3044
IMPORTANT:
Any unauthorised modification of the quick hitch may compromise the safety of the operator and
those nearby, and will invalidate the product warranty.

16 ©2022 Harford Attachments Ltd
SAFELOCK/GEN/MAN/R5
Warranty
Harford Attachments (the seller) warrants their quick hitches as follows:
1. The seller shall repair or replace at the seller’s option any of the goods which are, or which
become, defective within 12 months from delivery due to faulty workmanship, materials or faulty
design if the seller is responsible for the design, provided that the buyer shall have notified the
seller in writing of such defect (to include supporting photographic evidence) and having given the
seller a reasonable opportunity to inspect the defective goods.
2. If, in the opinion of the seller, the goods have not been operated or maintained in accordance with
the instruction contained within this manual, or have been subject to unauthorised repair or
modification, the warranty will be invalidated.
3. The seller’s liability in respect of defects in the goods shall be limited to those stated in this clause
and subject to Clause 2(1) of the Unfair Contract Terms Act 1997 (UK), the seller shall not be
liable whether in contract or in tort, including but not limited to negligence, or by reason of breach
of statutory duty or otherwise, for any damage or loss whatsoever suffered by the buyer arising
out of or attributable to such defects. For further technical or product information, contact us.
Europe: Spar Road, Norwich, NR6 6BY, UK USA: 4500 140th Avenue North, Suite 180,
Tel [phone] Clearwater, FL33762.
Tel: [phone]
Email: [e-mail] Website: www.harfordattachments.com