Assistant Professor of Mechanical Engineering

Pennsylvania State University

Engineering Contact & Technical Advisor

Ingersoll-Rand

1. Frame of Reference 1
1. Problem Overview 1
2. Design Requirements & Specifications 2
3. Project Objective 4

2.1 Technical Procedure 5

2.2 Schedule of Events 8

3.1 Preliminary Concepts 8

3.2 Concept Evaluation & Selection 12

3.3 Embodiment of Final Design 12

3.4 Design Testing 14

Appendix A: Schedule of Events 17

Appendix B: Team Members & Roles 19

Appendix C: Project Budget 20

The current design of Ingersoll-Rand’s VR-642 Telescopic Material Handler is limited by visibility problems. These occur mostly when the carriage is in the fully retracted and lowered position. In this position, the visibility to the right fork is virtually non-existent. The purpose of this project, completed by Lifting Lions Inc., is to remedy these problems.

Various concepts were generated to increase the visibility of the fork tips. Our sponsor, Ingersoll-Rand, directed the project toward the re-design of the parapet because of time limitations. All of the concepts were evaluated and the best one was chosen. The most feasible solution was to make use of the current attachment mechanisms and redesign the core of the parapet. Our solution involved enlarging the holes in the front and rear of the parapet to create a direct line of sight to the fork tips. If needed, the sides of the parapet can be reinforced to maintain the structural integrity of the design.

There are many additional requirements of this project that are also discussed. These include the schedule of events that are involved and necessary for the successful completion of the project. The project budget is also included within the appendices of this report. Deliverables to the sponsor at the completion of the project include CAD drawings of the redesigned parapet and a copy of this report.

1. Frame of Reference

Shown in Figures 1 and 2 are pictures of Ingersoll-Rand’s model VR-642 Rough Terrain Telescopic Material Handler. The VR-642 is designed primarily to lift palletized construction material and place it at the point of use. The current design of the VR-642, however, does not allow the operator to keep constant visibility with the fork tips as they engage the material to be lifted. Engaging a palletized load is accomplished by positioning the load bearing forks in front of the opening provided in the pallet, then either driving the unit forward until full engagement or hydraulically extending the boom to push the forks into full engagement. The current design restricts visibility from the operator's station and this impedes the performance of the vehicle, as seen in Figures 3 and 4 below.

The restrictions that the driver encounters are as follows:

1. As shown in Figure 3, the body of the VR-642 directly interferes with the line of sight to the fork tips.
2. The parapet directly interferes with the line of sight to the right fork, even when standing to see over the body of the vehicle, as shown Figure 4.
3. Part of the forklift carriage may also interfere with visibility of the right fork.

These restrictions can cause misalignment to occur during engagement of the forks with the pallet. If the forks are not aligned properly, damage to the pallet, and possibly the product on the pallet, may occur. Not only is there the possibility for damage, but the extra labor time spent carefully aligning the forks could be more efficiently spent. Thus, if the visibility can be improved, the process of moving materials will be safer, faster, and more cost effective.

In order to determine if the design concepts for the visible boom forks project are feasible or not, several requirements were established by team Lifting Lions, Inc. and its project sponsor, Ingersoll-Rand. These requirements are summarized in the Table 1.

The primary and most important requirement related to the actual proposed product was that the tips of both forks of the VR-642 must be visible from the driver’s position, especially during the material loading and unloading processes. Although it was suggested that this visibility should be through a direct line of sight, the use of mirrors or small video cameras was left as an option that could be used if needed. An additional wish was that the tips of the forks be visible in all carriage positions.

The second most important requirement is that the new parapet design must be compatible with the adjacent hardware and apparatus of the VR-642. Therefore, it must not only fit with the boom of the VR-642, but it also means that the quick attach assembly that currently exists must also be compatible. It is a goal of Ingersoll-Rand to be able to use as much of the existing model as possible to avoid increasing costs as manufacturing processes are changed to incorporate the new design.

The third requirement for this project is that the proposed carriage and parapet designs of the VR-642 must retain or have an improved structural integrity over the existing design. Any significant reduction in structural integrity would result in a required redesign and re-analysis of surrounding assemblies to determine maximum lift capabilities.

The fourth requirement established was that the proposed parapet must not reduce the capabilities of the existing VR-642. The proposal must maintain the vehicle’s maximum forward reach and vertical height characteristics.

The fifth requirement to be fulfilled is that the proposed parapet must weigh no more than the existing unit. Any additional weight to the parapet would require new load ratings with a reduced lifting capacity.

Likewise, the sixth requirement is that the current load face position must also be maintained. If the load face is moved forward, this would increase the moment arm of the vehicle and the maximum load that can be lifted would also be reduced.

If the carriage is redesigned as a part of the project, the geometrical relationship between the bottom of the forks and the bottom of the carriage must be maintained. This requirement was established so that loading and unloading capabilities of the VR-642 are not reduced.

In order to maximize the expected life span of the unit, two final requirements were established.

The first of these requirements is that the proposed solution must be corrosion resistant. This simply means that the final product would be painted or plated to existing standards to reduce the rate of corrosion of the bare material.

The last requirement to be fulfilled is that any hydraulic cylinders or lines must be protected as much as possible. This means that they should not be exposed in a way that they could be damaged by contact with the load or the ground. Hydraulic hoses must also be routed to avoid being pinched by moving parts of the VR-642.

The objective of this project was to improve the visibility of the VR-642’s fork tips by redesigning the parapet and fulfilling all of the design specifications. Matt Daschel and Joe Barney approved this objective on our second trip to the Ingersoll-Rand plant. Although the major visibility restriction is the body of the machine, it was collectively decided to concentrate on the parapet. The redesign of the body of the machine would be too time consuming for this project and was therefore dismissed as a possibility for improving visibility. Any improvement to the visibility of the machine by redesigning the parapet would be greatly helpful.

The approach specified by the Pahl & Beitz Design Process Flow Chart, shown below in Figure 5, was used to simplify the design process. The team tried to keep with the Design Process Flow Chart to maximize efficiency of time and available resources. As student engineers, using an established method of solving design problems was a clear and logical choice to start this project.

The first step in any engineering process is to identify the problem. Published problem statements in the PSU interdisciplinary Senior Design Projects – Fall 1998 described each of the problems for the respective groups. With the problem identified, clarification of the problem or task was the next step. The steps to clarify the task were as follows:

• Visit the company and see the problem in person
• Talk to the sponsor to get preliminary questions answered
• Get sponsor input on their needs, restrictions and specifications

Once the problem was well defined, the specifications supplied by the sponsor could be elaborated on to identify possible improvements. Improvements not specified by the sponsor may include lighter and cheaper materials, longer design life, and an increased factor of safety. Elaborating on the sponsor specifications can lead to exceeding the sponsor expectations, which is always good business practice but care must be taken to avoid overkill to prevent from wasting valuable time and resources.

The design process was positive up to this point, but to remain realistic, the negative aspects of the design had to be identified. The easiest way to accomplish this was to list possible problems or roadblocks that may be encountered. Possible problems may be that the technology has not been developed yet, economic restrictions, or even legal roadblocks caused by existing patents that would solve the problem.

Now that a wealth of knowledge has been accumulated, intelligent concepts were generated. As suggested by Pahl and Beitz, the focus of solving the problem at this stage should be developing conceptual solutions to the problem. There should be little attention given to limiting criteria such as cost and environmental impact, as generating the most ideas is the current goal. Limiting ideas to traditional approaches may overlook an abstract, yet effective, design solution. Ideas can be eliminated later, when deciding which concept to focus on. Generating the solutions started with solving one primary aspect of the problem. Producing conceptual sketches of the design helped to bring difficult ideas to an understandable level. It was important not to dive too deep into a solution at this point. If a solution was investigated too thoroughly, it may have biased one’s perception later when the concepts were being compared. Once ideas to solve the main problem had been generated, we elaborated on each of these ideas to solve more of the secondary problems.

Concepts could then be compared against each other to identify the primary concept or solution. This procedure of comparing ideas evaluated time restrictions, as well as how closely the design met the sponsor specifications and the elaborated specifications. Charts designed to list the strengths and weaknesses of each design were generated to help the process of determining the optimal concept. It had to be kept in mind, however, that new concepts and ideas could be generated at any stage of the process, and the procedure may need start over again. Thus, iteration was always a possibility during the design process for this project.

Creating the solution to the primary concept was the next step. A second plant trip was taken to clarify the problems of the existing design, and find the most critical areas of the visibility problem. The areas of greatest concern were identified and used to create an embodiment design.

Once the primary solution had been identified, an embodiment design was completed. The embodiment design included the detailed design of dimensioning, material selection and manufacturing process selection. The material and manufacturing process of the new parapet will remain unchanged if our proposal is accepted. However, the dimensions of the parapet were changed in two locations. The areas of both the front and rear faces of the parapet surrounding the actuating cylinder were enlarged to increase visibility through the middle of the parapet.

The next step was to create scale drawings of the parapet in a Computer Aided Design (CAD) package. From the drawings, the next step was to create models that could be tested to determine the effectiveness of the new design. The problem with the existing parapet was lack of visibility. The design will be effective if the design improves visibility while adhering to all the specifications.

Please refer to Appendix A: Schedule of Events on page 17 for a timeline of the team’s agenda.

Lifting Lions, Inc. had developed several concepts that had the potential of solving the fork visibility problem. These concepts are shown along with a brief description of how they would have worked and the thoughts that inspired them.

During the team’s first visit to the Ingersoll-Rand facility in Shippensburg, PA, it was noticed that the parapet wasn’t the only element that impeded vision of the fork tips. In fact, a large obstruction was the body and frame of the VR642. Concepts #1, #2 and #3 were thought of to eliminate the problem with the body and frame.

Concept #1: Raise the height of the driver’s seat and controls.

Concept #1 is almost self-explanatory, as raising the driver’s seat and controls would have allowed the driver to see completely over the front portion of the body and frame of the VR642.

Concept #2: Placement of the driver’s seat on a pivoting arm.

Concept #2 would allow the driver to see the fork tips by swinging the seat outwards. This would be done by incorporating a spring-loaded arm under the seat that would allow the operator to move outwards by pushing against the body of the vehicle.

Concept #3: Placement of the driver’s cabin on a hydraulic pivoting arm.

Concept #3 is a more elaborate version of Concept #2, but it would work along the same principle. This concept would place the entire cabin on a hydraulically actuated arm that would swing the cabin both outward and forward around the left front tire of the VR642. During the loading and unloading procedures, the driver could move the cabin out to the side and forward to give him a direct line of sight with the tips and the material to be loaded or unloaded. Once completed, the driver would then move the cabin back against the body for normal material transportation.

Concept #4: Twin Cylinder Parapet

Rough Sketch of the Existing Parapet Concept #4

While at Ingersoll-Rand, it was noticed that the biggest problem with the parapet is the placement of the hydraulic cylinder that is used to level the forks as the boom is raised. Using constant fluid volume, as the boom is raised by extending a cylinder at the base of the boom, the cylinder in the parapet contracts and levels the forks. By moving the cylinder out of the central portion of the parapet, more of the right fork could be viewed from the driver’s seat. In order to complete this task, two smaller cylinders (of overall equivalent volume to the existing cylinder) would be placed on the sides of the parapet, leaving the center of the parapet open for a direct line of sight.

Another option regarding the parapet would be to remove some of the material around the cylinder, and place reinforcing members on the outside of the parapet. This would create a larger window around the cylinder, through which the driver could see the forks.

Another option that was considered was the use of body-mounted mirrors to see the fork tips around any obstructions. Mirrors are often used to aid the process of backing up delivery trucks, so it was figured that there is potential to use it here as well. Exact positioning of the mirrors has not yet been established.

The last option that was considered was the use of small, closed-circuit video cameras mounted to the body and connected to monitors in the cab of the VR-642. This approach would be very similar to the sighting systems found in several military helicopters and aircraft for night vision capabilities. Exact positioning of the cameras has not yet been established.

During our second trip to Ingersoll-Rand, we were given the opportunity to have our thoughts and concepts evaluated by Matt Daschel, our technical contact. At this time, he reiterated the more significant requirements that our design had to meet. Table 2, shown below, illustrates how well each of the concepts met the design requirements.

As shown in Table 2 above, the most effective approach to solving the visibility problem was found to be enlarging the openings of the existing parapet. During the second plant visit to Ingersoll-Rand, we had the opportunity to sit in the operator’s seat of the VR-642 and determine where material needed to be removed from the parapet.

It was decided that the most effective places to remove material would be around the openings in the front and rear faces of the parapet where the actuator cylinder passes through. To retain structural integrity, the decision was made that the sides of the parapet could be thickened or reinforced if needed. For the new design, the large slot-shaped opening in the front face of the parapet was increased by an inch on all sides. In the rear face, the corresponding slot was lengthened downward by six inches and widened by an inch on each side. To illustrate these changes, the team utilized Pro Engineer (PRO/E) to produce drawings of the existing and proposed parapets. By comparing Figures 6 and 7, shown below, you can see the proposed changes to the parapet.

After the embodiment designs were completely drawn in PRO/E, the next step was to create prototype models of the parapets. Rapid prototyping was utilized to produce models of both the existing and the proposed parapets. The rapid prototyping machine used the PRO/E drawings as a reference and laser-cut successive cross-sectional layers of adhesive paper until the models were produced. Due to the nature of the rapid prototyping machine and the parapet parts to be modeled, the drawings of the front and rear plates had to have their thickness increased before rapid prototyping could begin. The result was that the assembled models were to scale when viewed from the front and rear, but the depth (the least important of the dimensions) was considerably out of scale. Since both the existing and the proposed models were out of scale by the same amount, it was presumed that it would have minimal affect on the testing of the designs. Once the drawings were loaded into the rapid prototyping machine, the total time to produce the physical models of the current and new parapets was approximately 28 hours.

The next step in the implementation of the solution was testing the design. To test how much the visibility was increased, we created a shadow box test apparatus. A hole was cut into one end of a cardboard box so that a flashlight could be inserted. A 7"x10" rectangular hole was cut into the other end of the box and a piece of white paper was used to cover this opening. The parapet models were then mounted into similar pieces of styrofoam that could easily inserted and removed from the box.

The actual test began by sliding the styrofoam with the old parapet model into place in the box so that the beam from the flashlight would be perpendicular to the back face of the model. We then traced a reference line around the edge of the styrofoam onto the inside of the box so that the second piece of styrofoam would be placed in the same spot.

With the flashlight turned on, the light pattern through the parapet model was traced onto the sheet of paper attached to the outside of the other end of the box. Finally, the model of the old parapet was replaced with the model of the new parapet and the process was completed by comparing the light patterns that were traced onto the sheet of paper at the end of the box.

Upon completion of the shadow box test, it was found that the new parapet design offered approximately double the visibility of the old parapet, with considerable difference noticed in the vertical plane.

The problem with the current design of the VR-642 Rough Terrain Telescopic Material Handler consists of the inability to see the right fork from the operator’s position. After visiting Ingersoll Rand it was obvious that there were various parts of the machine that restricted this line of sight. Upon further discussion of the problem with our technical contact Matt Daschel, it was decided that a redesign of parapet would improve the operator’s visibility when the boom is in a slightly extended position.

In redesigning the parapet, it was ideal that the design would not add cost to the current manufacturing of the parapet, be compatible with connecting hardware, and still meet the lifting capabilities of the machine. After visiting Ingersoll Rand for the second time, it was obvious that the removal of a small amount of material in the front and back of the parapet would improve the operator’s visibility.

Upon completion of the project, the deliverables to Ingersoll Rand will be the CAD drawings of the existing and new parapet designs and a copy of this report.

With the restrictions and limitations given, the redesign of the parapet has met all design specifications and improved the operator’s visibility without making a drastic change to the existing design. There are several benefits of the redesign including the following:

• There will only be a small initial cost in changing the cutting pattern of the steel and everything else will remain the same.
• The design will require very little manufacturing changes while increasing visibility.
• It will be compatible with existing hardware.
• The load-lifting capabilities of the machine will not change.

Even though the redesign of the parapet has proved to be successful, there is still one improvement that could be investigated. Visibility could be continually be improved by performing some research on cylinders to find a cylinder that is smaller, but can still provide the same load lifting capabilities. Furthermore, a redesign of the frame should be considered as a future project because it is also a contributor to sight limitations.

In conclusion, the redesign of the parapet has met all of the necessary specifications. Since the changes made in the redesign were very small, the parapet is ready for full-scale production with very few manufacturing alterations.

From left to right, the members of Lifting Lions, Inc. are:

The amount of money allotted by the Mechanical Engineering Department for the entire project was $500. This was more than adequate to fulfill all of our needs. This is a direct result of the group’s decision to use the rapid prototyping machine in the Learning Factory for the construction of the models. The majority of the costs that were reimbursed consisted of travel expenses to the Ingersoll-Rand facility in Shippensburg, PA. Another large portion of the budget was allotted for the preparation and construction of the posters to summarize the proposal and final design. The total amount of money expended by our group did not exceed $250.