Machine Labelling

Manufacturer	Buhl Maschinenbau e.K. Carl-Zeiss-Str. 2 71065 Sindelfingen
Machine designation	Locking unit
CE marking
Series / type designation	Manually actuated (H), manually actuated tandem (HT), pneumatically actuated (P), pneumatically actuated tandem (PT), electromagnetically actuated (EM), electromotively actuated (EMOT) (e.g. SA 25H, SA 30HT, SA 50P, SA 30PT, SA 50EM, SA 50EMOT)
Serial number	e.g. SA 14 314.1 (consecutive numbering by year, order number and quantity)

Declaration of Conformity

We declare that the safety component described below meets all relevant provisions of the Machinery Directive 2006/42/EC.

We wish to point out that the safety component may not be put into operation until, if applicable, it has been ascertained that the machine to which the safety component will be attached complies with the provisions of the Machinery Directive 2006/42/EC.

Other applicable directives:
2004/108/EC (Electromagnetic compatibility)

Applied harmonized standards:
DIN EN ISO 12100:2011-03
DIN EN 60204-1 correction 1:2010-05

Other applied standards and specifications:
None.

Sindelfingen, January 1, 2013
Andreas-Reinhard Theil
Managing Director and Owner

1. General Remarks

1.1 Introduction

A locking system (referred to below as LS) consists of two single locking units (referred to below as LUs) or a tandem LU as well as a slotted disk or bar that the locking bolts of the LU slide into. When planning the entire system, the designer must pay attention to the installation instructions (2.) for the LU.

1.2 Actuators & Sensors

Fitting the locking and control units with electrical safety limit switches and pneumatic cylinders is only done according to customer requirements and after approval of procurement sources.

The electrical safety limit switches of the LU are available with two different types of actuation: Bolt synchronization and bolt alternate engagement.

1.2.1 Bolt synchronization

When unlocked, both safety limit switches are closed (closed circuit principle). A limit switch working under the closed circuit principle effects a shutdown as soon as the locking bolt is moved out of its rest position (unlocked).

1.2.2 Bolt alternate engagement

When unlocked, the front safety limit switch is closed, the rear one is open, when locked it is in the opposite state. With two-channel signal evaluation, an offsetting signal change needs to take place in each case.

1.3 Intended Uses

The LS can be used as a servicing or indexing unit. Mechanical LUs give the maintenance, repair and cleaning personnel the option of securing the system to be entered in such a way that no unintended or unauthorized machine movement is possible. For this application, our locks are maintenance-free.

For use as an indexing unit - i.e. for actuation in the machine cycle - LUs with hardened bolts and bearing bushes with solid lubrication inserts must be used.

1.4 Electrical Equipment

The electrical safety limit switches of the LU trigger shutdown through the hardware and work according to the closed circuit principle. LUs are fitted with safety limit switches with roller tappets according to customer specification.

1.5 Colour

All LUs are painted RAL 3000 red.

1.6 Models / Types

The models vary in the way they are actuated and the locking mechanism (permissible load):

1.6.1 Manually Actuated Locking Unit (single and tandem)

This LU does not have a preferred installation position. The locking bolt is moved manually from the detent position to the locked position. For this purpose, the actuating handle needs to be raised out of a detent hole, so unintentional or unknowing actuation is impossible. This also applies to unlocking.

Manually actuated single LU:

Manually actuated tandem LU:

1.6.2 Pneumatically actuated locking unit (single and tandem)

The preferred installation position of this LU is with a horizontal locking bolt. However, after consulting the manufacturer, other installation positions are also possible. The locking bolt is kept in the “unlocked” position (rest position) by a pneumatic cylinder. When the pneumatic cylinder is actuated, the locking bolt moves to the locked position. Unlocking is triggered by the pneumatic cylinder being actuated in reverse. As an option, it can be controlled by the U 1836 or PV control unit.

Pneumatically actuated single LU:

Pneumatically actuated tandem LU:

1.6.3 Electromagnetically actuated locking unit (single and tandem)

This LU may only be installed with horizontal locking bolts! With electromagnetic operation, the locking bolt does not have a defined detent position. The actuating magnet has two electrical connections, one to lock, one to unlock.

Electromagnetically actuated single LU:

Electromagnetically actuated tandem LU:

1.6.4 Electromotively actuated locking unit

This LU does not have a preferred installation position. The servo motor to actuate the locking bolt has an integrated control and power section with two electrical connections for locking and unlocking.

Electromotively actuated single LU:

With the electromotively actuated model, tandem LUs are also possible.

On customer request, special LUs are also manufactured. For example, with a single acting pneumatic cylinder or a spring on the locking bolt. Effect: If the air pressure falls, the LU will automatically close due to the compression force of the spring.

1.7 Function

Due to fixing bolts, the LU acts mechanically on the machine parts it is attached to. The safety limit switch is integrated into the higher-level controller by the customer.

To secure the system against unauthorized reactivation, a padlock must be fitted directly to the housing of a manually actuated LU (6.1) that is locked.

To secure the system against unauthorized activation, a padlock must be attached in the locked position with pneumatic operation (6.2) and control unit LU 1836 or PV (10.).

1.8 Machine Movements

Dangerous machine movements are ones like shuttle movements, lifting frames, lifting equipment in transfer stations to other systems or lifting equipment in conveyor technology and lifting equipment in storehouses.

Safety locks are required:

• for lifting equipment for a lift of more than approx. 280 mm
• for large rotational movement with potential energy
• for weights with an impact force of more than 150 N

1.9 Pneumatic Installation

The control pressure required to supply the safety lock (4.5 bar) must be taken directly from the hall network (6 bar) in front of the shutoff valve of the production facility. Lines should be selected to have a diameter of no less than 12x1 mm and an internal diameter of 9.5 mm (hose).

Before assembly and commissioning, completely clean out the pneumatic lines!

1.10 LU 1836 and PV Control Units

The control unit consists of an electrical safety main switch, a magnetic valve and a pressure switch. The LU 1836 and PV control units differ due to the number of switch positions; there is also no magnetic valve and no pressure switch in the following models of the PV control unit: 01-PV-02, 02-PV-02.

The manually actuated LU 1836 or PV control unit is used to centrally operate the pneumatically actuated LU, especially with shuttle or lifting movements. Rotating the selector switch to one of the positions
“Blue“ or “Red”-locked is only possible if all the locking bolts have reached the “locked” position.

Locking the system may only take place if the system is at a standstill (cf. “(2.3) Operation”)!

To protect the maintenance personnel from unauthorized unlocking and reactivating of the system, a padlock must be attached when it is locked.

Locking is possible in any position – using two LU switched in parallel and a slot disk with an uneven number of slots. Engagement of at least one of the locking bolts is guaranteed.
In accordance with the bolt diameter and the selected web width between the slots, overtravel can occur for system reasons (cf. “(2.4) Installation, overtravel”).

Functional description for the sample wiring diagrams:

Rest position - unlocked state

The 5/2 directional control valve in the control box, which is controlled by the “unlocked” position of the switch selector, holds all locking bolts in the “unlocked” position using the controlled pneumatic cylinder. The electric switch selector can only be turned between the positions “unlocked” and “standby position”. A built-in magnetic lock prevents switching in one of the positions “blue” or “red”.

Lock position

The switch selector is moved to standby position. The e-magnet on the switch selector prevents it from turning further to one of the positions “blue” or “red”.

The 5/2 directional control valve in the control unit reroutes the LU cylinders, which are then inserted into the lock openings on the machine drives to be secured. Immediately after the cylinders move, the first safety limit switch is activated. and the second limit switch is activated at the end of the stroke. The first limit switch switches off all drives using the hardware. The magnet on the selector switch only allows it to switch on to one of the “blue” or “red” positions if the signal from the second limit switch is received. A padlock can then be attached. A red display light on the central operating cabinet shows that it is locked. A pressure switch in the control unit monitors the air pressure setting of 4.5 bar.

All LUs centrally actuated using the LU 1836 or PV control units must be switched in accordance with the specific applications in compliance with the sample wiring diagrams. The selector switch with a magnetic lock made by Kraus & Naimer is supplied by Völmle & Rickert.

2. Installation Instructions

2.1 Introduction

The installation instructions apply equally for all models.

2.2 Permissible Load

The maximum forces assigned to standard locks may not be exceeded, taking all dynamic and static forces for hydraulically and pneumatically actuated devices into account. The direction of the force (P) acting on the locking bolt can be randomly selected. However, it must always be applied at a 90° angle to the bolt axis. Pay attention to the maximum load depending on the different directions of forces.

2.3 Activation

The manually actuated LU 1836 or PV control units can be used to activate the pneumatically actuated LU. LUs may only be actuated when the machine is at a standstill. For this reason, highly visible notices must be displayed where LUs are installed with the text:
Only activate lock when at a standstill

2.4 Installation, overtravel

The LS must be installed as follows:

2.4.1 Two Single LUs

The two LUs are to be fitted opposite each other on the slot disk. The number of slots in the slot disk must be uneven!

2.4.2 One Tandem LU

The tandem LU is only to be fitted in one location. The number of slots in the slot disk must be uneven! The slots in the slot disk must be longer that the distance across the two bolts of the LU. The webs between the slots must be narrower that the distance between the bolts.

The LUs are always embedded in a groove on the base plate of the receiving part (machine body, bearing bracket, etc.) and are screwed into place. The groove dimensions specified on the standard sheets as well as the screw tightening torques and quality must be complied with.

The LUs (with slot disks) must be installed in the fast-running part of the drive system or in direct connection with a slip clutch (if present) so that in dangerous places - if possible - a maximum overtravel of 30 mm is aimed at on the customer side. Depending on the length of the slots on the slot disk selected by the customer, the overtravel may be greater.

Between LU and slot disk there is a crushing and shearing point that the designer of the overall system needs to evaluate. They must take any necessary safety precautions.

All welded seams on power transfer components must be designed with a five-fold safety margin. The welding must be carried out by a certified welding specialist according to DIN ISO 5817-C (quality of welding seam) and DIN 13 920 (tolerances for welded constructions).

2.5 Safety factors, residual risks

All LUs are designed with a five-fold safety margin. All intermediate elements in the power transmission chain from the LU to the machine body or frame, such as bearing blocks, brackets, screw connections, slot disks, slot bars etc., are also designed with a five-fold safety margin against breakage.

Sigma_actual = Sigma_perm. = Sigma_B / 5

The factor 5 contains the following coefficients:

• Safety factor
• Type of stress (tension, pressure, bending, thrust)
• Load (resting)
• Type of seam (fillet weld, butt weld, etc.)
• Component-related coefficients (size and surface area values and notch effect value)

Residual risks:

Between the LU and the slot disk there is a designated gap of 15 mm. At this point, there is the risk of shearing and crushing. To minimize the risk, the customer must fit a cover plate that neutralizes the area of risk.

If the slot disk rotates, there is the risk of crushing and shearing between it and the LU. To minimize the risk, the customer must fit a solid disk (with only two holes for the locking bolts) between the slot disk and the LS.

2.6 Final inspection

The LS of a system must be inspected by the distributor as part of the final machine inspection once assembly has been completed on the customer's premises.

Version 2014-11-12