Basic Hand Signals In Crane Operation

Cranes are commonly used in the construction of towers and industry, and in manufacturing heavy equipments. Cranes ranges from small site crane to big cranes and deck cranes that lift heavy equipments. Basically, they are temporary structures in construction. They are either fixed on the ground or hoarded on a purpose-built vehicle. Cranes come in different types such as jib, gantry, ship and deck, bridge or overhead, boom, tower, and mobile or truck.

Before operating the crane, operators should carefully read and understand the operation manual from the crane manufacturer. Further, they must always note any instructions given by a reliable instructor or operator. It is also crucial for the crane operator to understand the consequences of careless operation of cranes. They must be instructed of the proper use, prohibition and the safety rules and regulation during the operation.

It is always the responsibility of the owner to make their personnel aware of all federal rules and codes so as to preclude violations along with their penalties. Employers must also make certain that their operators are properly trained and are equipped with the know-how. To be safe in the operation of crane, it requires skill and exercise of great care and ideal foresight, alertness and concentration. Also strict adherence to proven safety rules and practices is necessary.

The personnel who handle the operation of cranes in an area must utilize hand signals, if necessary, as their means of communication. Here are the most commonly used hand signals during crane lifting operation:

1. HOIST. Raise the forearm vertically and extend the right arm straight out with forefinger pointing up. Then, move hand in small horizontal circle.

2. LOWER. Forefinger pointing down and extend right arm downward then move hand in small horizontal circle.

3. STOP. Extend right arm down with wrist bent, palm down and open.

4 SWING. Right arm away from body, point with finger in direction of swing of boom.

5. RAISE BOOM. Fingers closed and thumb pointing upward while extending the right arm straight out.

6. LOWER BOOM. Fingers closed and thumb pointing downward while extending the right arm straight out.

7. BRIDGE TRAVEL. Extend the right arm forward, hand open and slightly raised and make pushing motion in direction of travel.

8. TROLLEY TRAVEL. Thumb pointing in direction of motion with palm up and fingers closed, jerk hand horizontally.

9. EMERGENCY STOP. Extend right arm, palm down and move hand rapidly left and right.

10. MULTIPLE TROLLEYS. For block marked 1. hold up one finger, and two fingers for block marked 2. Regular signals come next.

11. RAISE BOOM and LOWER LOAD. Right arm extended and thumb pointing up. Flex fingers in and out as long as load movement is needed.

12. LOWER BOOM and RAISE LOAD. Right arm extended and thumb pointing down. Flex fingers pointing in and out as long as load movement is needed.

13. DOG EVERYTHING. Hold hands in front of the body.

14. MOVE SLOWLY. One hand gives any motion signal while the other hand motionless in front of hand giving the motion signal.

15. MAGNET IS DISCONNECTED. Spread both hands.

When using these hand signals be sure that you and the crane operator are familiar with these signals. A wrong signal could cause a serious injury or worst – death.

Always stay alert when you are working in construction near any crane. If possible, avoid working under a moving load and stay clear of the counter balance. Always use your safety devices and helmet to avoid injuries. Safety is always the top priority of all workers and the crane operator.

OSI Layers Model


During the early years of our modern computer era, very few standards and protocols existed between various manufacturers. However, as time went on and computer technology continued to improve and become more widespread, it became apparent that standards would be necessary to ensure compatibility. This was especially true with regard to networks, and networking technology. Since the main purpose of a network is to share information, a standard that governs how this information is formatted, transmitted, received and verified would make it possible for information to be shared openly, even when dealing with dissimilar networks.

This need for a standard means of implementing open communications led the ISO and ANSI to develop the seven-layer network communications model known as Open Systems Interconnect. By providing guidelines regarding the way network equipment should be manufactured and how network operating systems communicate on a network, the OSI model became the common link that allows data to be transmitted and exchanged reliably. Although it does not actually perform any functions or do any of the actual work, the OSI model defines the way things should be done by the software and hardware on a network so that communications can take place between two computers or nodes.

In this way, the OSI model provides a universal set of rules that make it possible for various manufacturers and developers to create software and hardware that is compatible with each other. This makes for organized communications. As I thought about this, I related it to the freeways that connect the various states of the mainland U.S. Because all of these freeways were constructed with the same set of standards regarding the width of each lane, the proper side that a person should drive on, the speed at which they should travel, and so on, people can comfortably drive across the country in an organized and efficient manner and car manufacturers are able to design cars within these guidelines as well.

On the other hand, if each state had devised its own set of rules, each differing from the other, not only would there be a lot more chaos on the roads, but also car manufacturers would have a hard time designing vehicles that would be compatible with each state’s roads. To me, this illustrates the importance of the OSI model with respect to network communications. Not only is it the foundation for all network communications today, but also because it is such a fundamental part of these communications, it becomes very apparent to me that it is very important for a network technician to understand the OSI model in full detail.

The OSI model is made up of the following layers: the physical, data link, network, transport, session, presentation and application. Together, these seven layers are collectively referred to as a stack. As a node receives data, each layer starting with the physical layer extracts the various portions of the packet and this process works its way up to the application layer. When data is sent, it begins at the application layer and travels down to the physical layer. The information is pushed to the next layer of the stack by means of commands called primitives. Each layer uses a peer protocol to encode the information, which ensures that the same layer on the receiving node will be able to understand the information.

Physical Layer

Beginning at the bottom, the first layer is the physical layer. It governs the actual voltages, type of electrical signals, mechanical connections and other items relating to the actual data transmission medium. This includes cabling types, distances and connectors, as well as protocols like CSMA/CD.

Data Link Layer

The next layer is the data link layer. This is the layer that actually constructs the frames, and it also performs error checking using CRC. It ensures that the frames are sent up to the next layer in the same order that they were received, providing an error free virtual path to the network layer. The data link layer consists of two sub layers; the logical link control (LLC) and the media access control (MAC), which provide reliable communications by ensuring the data link is not broken and also by examining packet address information. A bridge is an example of a device that works at this layer. A bridge learns, forwards and filters traffic by examining the layer 2 MAC address. This helps segment network traffic. More recently, bridges have been replaced by switches, which performs the same functions as a bridge, but can do so on each port. To find out more about switches, visit the Products link on the left.

Network Layer

Moving up to the next layer in the stack we come to the network layer. This layer actually routes packets of data, finding a path (both physical and logical) to the receiving or destination computer. It provides a unique address for each node through address resolution. One of the most common protocols for routing information at this layer is the Internet Protocol (IP). An example of hardware that can operate at this layer is a router. Although routers are often used to allow a LAN to access a WAN, layer 3 switches can also provide routing capabilities, but often at full wire-speed.

Transport Layer

The transport layer makes sure that the data arrives without errors, in the proper sequence and in a reliable condition. It uses flow control to make sure that information is sent at the proper speed for the receiving device to be able to handle it, and it repackages large data into smaller messages and then back again at the receiving node. An example protocol at this layer is the Transmission Control Protocol (TCP). Layer 4 switches can use the port information found in the TCP header to provide QoS (Quality of Service) and load balancing. To learn more about multi-layer switches, visit the Products link.

Session Layer

The session layer establishes the link between two nodes and ensures that the link is maintained and then disconnected. This is referred to as the session. It also makes sure the session is orderly, establishing which node transmits first, how long it can transmit, and what to do in case of an error. It also handles the security of the session.

Presentation Layer

The presentation layer deals with the actual formatting of the data. It handles compression, encryption, as well as translation to make sure differences in formatting can be read by the receiving node. For example, data might be converted from EBCDIC to ASCII formatting so that the receiving node can understand it.

Application Layer

This brings us to the seventh and final layer, the application layer. It allows applications access to network services, such as file and printer sharing, as well as file transfer and management services. This would be the layer that a programmer uses to allow his application to access a network service, such as linking into a database.

Although this explains the flow of data and what processes are performed by each layer starting with the physical layer and working to the top, or application, layer, the process would be the same, only reversed, for data flowing from the application layer and down to the bottom, or the physical layer.


By adhering to this standard model of communications, modern networks, including the Internet, have come into existence. For anyone interested in implementing and supporting today’s modern networks, an understanding of the OSI model and its various layers is crucial. Indeed, this standard of communications lays the foundation for all of today’s modern network hardware and software.

Outsourcing – What Are the Advantages and Disadvantages of Outsourcing?

Outsourcing is a common business strategy. Organizations outsource functions, activities, processes and decision responsibility to outside providers. Outsourcing is done through contract agreements with vendors that take on the risk and responsibility for the quality, people management, process and service of a business function. Outsourcing helps to reduce organizational overhead costs.

So why do organizations outsource?

Organizations outsource so they can reduce their operating costs and have more time to focus on their core business. Outsourcing allows an organization to outsource an entire function or just a part of it. For example, you can outsource the payroll function while keeping the rest of the accounting function in-house.

Outsourcing can be part of a strategic initiative to reduce costs and improve customer service and quality. It can be flexible and used for a permanent solution or as a temporary arrangement to learn improved techniques, redesign a faulty product or bridge a staffing gap.

Businesses should look for outsourcing opportunities and potential areas within the organization to determine if all or just part of a function should be considered for outsourcing.

Every organization is different and may have varying needs for outsourced services. Some of the more common operational functions that can be outsourced are:

  • Accounting
  • Customer Support
  • Facility Management
  • Human Resources
  • Information Technology
  • Legal
  • Manufacturing
  • Marketing
  • Order Fulfillment
  • Payroll

Outsourcing Advantages

Core Business Focus

Organizations that outsource functions of their operation have the ability to focus on their core business and what they are good at. As organizations grow, they are required to deal with business functions outside of their expertise. Leadership spends time and energy trying to learn and manage a system or function that they may know nothing about. This distraction can take away from focusing on their core business. An example of this would be a grocery store that adds video rental to their business. If the store puts too much focus on the video side of the operation, they may lose focus on groceries which is their core business.

Cost Savings

Cost savings can be significant with outsourced business functions. Savings can be in compensation costs, manufacturing setup or expenses associated with office space. These savings free up resources that can be used for other purposes.

Enhanced Quality

Quality can be improved by utilizing vendors who have the expertise and specialization for some functions. An example of this might be outsourcing a custodial function. A custodial vendor would often be more equipped for facility inspections, hiring and training that might not otherwise be available if done in-house.

Higher Customer Satisfaction Scores

Vendor agreements typically guarantee certain levels of quality and service that may be more difficult to manage in-house. An example of this might be if the custodian calls in sick, it is the vendor’s responsibility to find a replacement to meet a contractual agreement.

Efficiency in Operations

Vendor specialization offers increased levels of efficiency that can provide quicker turnaround and higher levels of quality. These specialized vendor processes can be more efficient because it is the vendor’s core business.

Disadvantages of Outsourcing

Service Quality

It is important to make sure that there are measurable levels of service quality written into the vendor agreement. It is common for vendors to leave these measurable service levels out of the agreement to save on costs.

Quality Risks

Outsourcing does expose organizations to certain public relations, legal and potential quality risks. An example of this would be if a car has faulty parts and is recalled, and the faulty part was outsourced, the car manufacturer still carries the burden of correcting the problem. The vendor would need to correct the issue but the negative public perception would need to be addressed by the manufacturer.

Language Barriers

When customer call centers are outsourced to a country that does not speak fluent English there may be a language barrier. Customer dissatisfaction can happen when a customer service rep has a strong accent that is difficult to understand.

Public/ Employee Opinion

There can be public and employee sympathy for employees who lose a job that is now being outsourced. This is sensitive and needs to be handled with compassion and tact. Communicating such changes needs to be diplomatically strategized to minimize the negative impact.

Tacit Knowledge

Outsourced employees do not share the same tacit knowledge and passion for the organization as regular employees. When outsourced employees come in contact with customers, they may not have the same knowledge base of the organization.

Organized Labor Issues

Organized labor has strong feelings about, and has resisted outsourcing to other countries. Pro-labor groups oppose this management approach that is perceived to result in a lower standard-of-living and worse working conditions. This perception can affect workforce productivity as it responds to corporate outsourcing.

Security and Legal Compliance

Outsourced functions need to be managed to ensure system security and legal compliance. Processes that involve security or legal compliance should be formally addressed through documentation. For example, an outsourced customer support person may have access to confidential customer information that could be used inappropriately.

Reduction in Force

Employee layoffs can be a common result of outsourcing. A well planned strategy for outsourcing will do so through attrition and job reassignment. This can be difficult but can help offset morale issues with remaining employees.

Organizations should have a well thought out strategy and plan for outsourcing functions of their business. It also is important to solicit at least three Requests for Proposals (RFP) to ensure the best use of resources.