Criteria for choosing stringing blocks

Criteria for choosing stringing blocks are as follows.

a)    For best results during the stringing and sagging operations, the minimum diameter at the bottom of each conductor sheave groove (sometimes called root diameter) should be:

D_S =20D_C−10

Where D_s and D_c are in centimeters and Dc is the diameter of the conductor to be installed.

NOTE the above ratio may be exceeded as required by some countries, codes.

b)    The minimum depth of the sheave groove should be:

Dg = 1.25Dc

c)    The minimum groove radius at the bottom of the groove should be:

Rg =1.1D_C /2

The groove profile and the groove radius should be wide enough to allow passage of conductor swivels and woven wire grips without these riding high in the groove and imparting a shock load to the sheave. It is important also to consider the shape of the sheave groove if it is desired to make conductor compression joints in front of the tensioner and pass these through the stringing blocks. In this case a wide sheave groove should be considered.

d)    The sides of the groove should flare between 30° and 40° from the vertical to facilitate passage of swivels, conductor compression joints, conductor woven wire grips, etc.

e)    It is appropriate that the chassis of the unwinding pulley allows a top or side opening for easy removal of the drivers during the setting clips operation.

It is appropriate that the groove of the pulley peeling or location through which the driver is designed to allow passage without shaking a peeling rudder in the case of a beam, or tablet sleeves driver, swivels, pulling loops of cable, etc. It is appropriate that these objects do not come into contact with the frame of the pulley.

SPW Model 45T removable winch ZECK

The notion of These winches can it be That Is Transported by helicopter and enable THUS Their collection sites inaccessible. For This reason They are removable parts, none of them not Exceeding 1,200 kilograms.

I says sales engineer selling These machines That the main difficulty is to break the philosophy of "spend the Least on teams." In principle, it is valued only the price of equipment and not Properly value the time lost due to delays, lack of productivity and other Risks by collecting not ready computers to access difficult locations. and, on the other hand, ASSESS the prestige of the company Effectively solves That player down with Difficulties, as is the crossing of a fjord.

Now When a machine like Zeck SPW 45T give an example of efficiency, productivity and safety, carrying crosses in Several fjords in Norway, or doing work on oil rigs in Malaysia and China, demonstrating ITS profitability and being listed as a top team, the price of equipment passes a lower level.

Always difficult to introduce a new team, even When the currency issue is not important.

Most Important features of this model ZECK SPW 45T are:

Maximum force 450 kN. Maximum weight of 1,200 kg each piece.

With crane for self-assembly. 8050 kg weight set.

Pair of drums adhesion: 1,800 x 1,700 x 1,500 mm. Weight 1,800 kg.

There are versions With maximum pulling force of 19, 30, 35, 38 and 45 tons.

More information www.zeck-gmbh.com

Wire Rope Clip Safety Notice

Under the approved Code of Practice for Load Lifting & Rigging, slings assembled with wire rope clips are not to be used for lifting

To comply with manufacturer’s specifications the correct number of clips must be installed correctly and tightened to the correct torque using a torque wrench. The correct installation technique is shown below.

When fitting clips “Don’t straddle a dead horse”.

A visual inspection should be carried out prior to and during use.

Wire rope clips should be inspected before use to ensure that:

• all markings are legible;
• the wire rope clip is free from nicks, gouges and cracks;
• a wire rope clip with the correct dimension has been selected;
• never repair or reshape a wire rope clip by welding, heating or bending as this may affect the performance.

The wire rope clip should be fitted to the wire rope as shown in the diagrams below. The bridge of the wire rope clip should always be placed on the load bearing part of the rope. The U-bolt of the clip should be placed on the rope tail, also known as the “dead end” of the rope.

Turn back enough wire rope length so that the required minimum number of clips can be installed according to the instructions below.

The first clip must be placed one bridge width from the turned back rope tail or dead end of the rope, according to figure 1. Tighten nuts to the specified torque.

The second clip must be placed immediately against the thimble but nevertheless in such a position that the correct tightening of the clip does not damage the outer wires of the wire rope (figure 2). Tighten the nuts firmly but not yet to the specified torque

The following clips should be placed on the wire rope between the first and second clip in such a way that they are separated by at least 1½ times the clip-width with a maximum of 3 times the clip-width according to figure 3.

Apply light tension on the rope and tighten all nuts evenly, alternating until reaching the specified torque.

During assembly and before the rope is taken into service, the nuts must be tightened once again to the prescribed torque. After the load is applied for the first time, the torque value must be checked again and corrected if necessary. Periodically re-tightening of the nuts must be done at 10.000 cycles (heavy usage), 20.000 e.g. every 3 months, 6 months, annually.

The torque values and the minimum number of clips to be applied, in relation to the rope size, are given in the following tables.

Table 1, Wire rope clips required number and torque value

Diameter	Diameter	Min no of clip required	Length of rope to turn back	Torque value	Torque value
Inches	mm			Nm	Ft. Lbs
1/8	3-4	2	85	6.1	4.5
3/16	5	2	95	10.2	7.5
1/4	6-7	2	120	20.3	15
5/16	8	3	133	40.7	30
3/8	9-10	3	165	61	45
7/16	11-12	3	178	88	65
½	13	3	292	88	65
9/16	14-15	3	305	129	95
5/8	16	3	305	129	95
¾	18-20	4	450	176	130
7/8	22	4	480	305	225
1	24-25	5	660	305	225
1 1/8	28-30	6	860	305	225
1 ¼	32-34	7	1120	488	360
1 3/8	36	7	1120	488	360
1 ½	38-40	8	1370	488	360
1 5/8	41-42	8	1470	583	430
1 ¾	44-46	8	1550	800	590
2	48-52	8	1800	1017	750
2 ¼	56-58	8	1850	1017	750
2 ½	62-65	9	2130	1017	750
2 ¾	68-72	10	2540	1017	750
3	75-78	10	2690	1627	1200