General Purpose Safety Crane

Jared Bush

Curtis Blank

Zane Jacob

Katelyn Cockrell

Alexandria Williams

Professor: Cris Koutsougeras

Advisor: Ho-Hoon Lee

ET 493 - 01

November 17, 2016

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Table of Contents

Abstract pg. 3

Progress pg. 4 - 15

Deliverables/Timeline pg. 16

References pg. 17

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Abstract

The objective of this project is to design a general purpose safety crane that can

be used in a variety of industries. The purpose of this project is to prove that we have

gained knowledge throughout our engineering curriculum and that we can put that

knowledge into perspective. Our senior project is going to involve knowledge from

courses that we have taken in the past including mechanical design, strength of materials,

statics and so on. The crane will be mounted onto a trailer, allowing it to be mobile. The

fact that the crane will be mobile and allow to be repositioned will also make it unique.

The main purpose of the crane is to allow workers painting the tops of tanker trucks to

secure themselves and use the crane as an anchor point. The crane will be expected to

support a load of 5000 lbs., which is the maximum weight of someone falling.

Currently there are only a few cranes on the market that could compare to our

design. Like our design, some cranes currently available use electric winches to lift

objects and some are mounted on trailers as well. What separates our design from the

cranes currently available is that our crane will use an overhead trolley that will follow

the worker. This will allow the worker to move freely and not be concerned about his/her

safety.

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Progress

Overall Crane Design:

For the design of both the trailer and crane, we had to solve for static and dynamic

loads. This involved finding forces on objects and determining how to go about finding

what material that was best for the application. To help assist us in the design, we used

programs such as MATLAB and AutoCAD Inventor. These programs helped us test our

design to ensure everything was working properly. Specifically, in AutoCAD inventor we

were able to distribute loads and run the design through a simulation.

Trailer:

For the design of the trailer, we will be using 4”x3”x1/4” steel tubing for the

frame. The size of the trailer will be approximately 6’-8” by 10’. We decided on this size

because we needed it to fit between the tires of the eighteen wheeler tanker. There will be

two ten-foot tubing sections, three feet away from each other, running down the center of

the trailer. There will also be two six-foot tubing sections running across the middle of

the trailer, three feet away from each other and intersecting with the two ten feet tubing

sections running down the middle of the trailer. There will be four jacks mounted to the

trailer, one on each corner, to allow stability in all directions. The jacks will be

extendable and constructed of tubing which will slide out of the main frame. Allowing

the jacks to extend out will create a larger workspace and sturdier base. We will drill two

holes in both the frame tubing and the tubing the jacks will be attached to. The holes will

be for when the smaller tubing is extended; you can insert two locking pins in the two

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holes. We decided to use two holes to reduce the amount of bending in the smaller tube.

Also, one hole will be drilled through both pieces of tubing so that when it is retracted a

pin can be inserted to prevent the smaller tubing from sliding out while towing. The large

eighteen wheeler tankers have a fifteen-foot gap between the third and fourth set tires.

This gap is where the trailer will be pulled alongside the truck. The two jacks that extend

toward the tanker will extend telescopically with two pieces. We thought about having

them fold instead of extend, but then they would not be able to go under the truck. The

overall length of the jacks will be 14 feet. The inner piece will be 9 feet in length, 7 of

which will be exposed while 2 will stay in the other section of tubing. It will be

constructed of 4.5x4.5x3/16 wall A500 Square Steel Tubing. The outer piece will also be

9 feet in length, 7 of which will be exposed while 2 will stay in the inner section of

tubing. It will be constructed of 4x4x5/16 wall A500 Square Steel Tubing. Each section

will have an electric jack for stability. We considered using hydraulics, but the electric

jacks were cheaper and more user friendly. The two jacks on the opposite side will

extend three feet out at a forty-five-degree angle. They will be constructed of 4x4x5/16

wall A500 Square Steel Tubing and the jacks will also be electric. We decided on a 2000

lb. double axel since it will just have to support the weight of the crane and not any loads

because the jacks will be handling that. The trailer will have lights for towing, which will

require an electrical hookup to a vehicle.

Crane:

The crane will use a relatively popular jib crane design. We decided on this

because we needed a large boom, but did not have the space for a large angle. The pillar

of the crane will be constructed of hollow cylindrical tubing and be 20’ in height and be

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mounted to 2’ from the edge of the trailer. The boom will be constructed of a 19’ I-Beam,

which will allow us to use a trolley mechanism to contribute to the fall protection of the

worker. We researched two trolleys that we thought would work, but ultimately decided

on Climbtech’s I-Beam Trolley because it was the cheaper of the two and weighed less.

Climbtech’s I-Beam Trolley Anchor is designed for fall protection, rope access and work

positioning. The trolley is constructed with lightweight aircraft aluminum bars and 360-

degree swivel D-Ring connectors. The key features of this trolley is that it weighs 7.7

lbs., it can be mounted on a flange of 3 to 10 inches, and has a breaking strength of

5,000-pound force. An angle sensor will be attached to the trolley, to allow the trolley to

move with the worker. The pillar will be able to pivot, allowing the user to turn the boom

while in operation. The pivoting portion of the pillar will be mounted at the top end. It

will have an upper and lower mount flange. The upper mount flange will have a bolt

pattern diameter of 18.874”. The lower mount flange will have a bolt pattern diameter of

14.374”. The two flanges will be connected using twenty 5/8”-11 thread. It will use a

bearing system capable of operating under the required conditions. A Rotek Brand rotor,

product number A12 - 18E5, will be used. In addition, the rotating part of the pillar will

have a locking system to keep the boom from swinging while in use. The boom of the

crane will be mounted to the pillar using brackets.

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Calculations/Drawings:

** The below diagrams and charts are the results of an online bending stress calculator.

The forces, distances of forces, and size of beam were inputted and in return the output

parameters/results were given. **

General SpecificationsMax Anticipated Load (lbs) 5000Maximum Radius (ft) 19Pillar Height (ft) 20Intended Load (lbs) 250Safety Factor (OSHA Reg.) 5Max Fall Distance (ft) (OSHA Reg.) 3.5Inertia CalculationVelocity (Vf= Vi^2+2*a*d)(ft/s) 15.0025531Inertia (lb*ft/s)(p=mv) 3750.63828Bearing CalculationWeight of load (lb)("A") 5000Distance from the center of gravity to center of rotation (ft)("a") 19Weight of the boom section (lb)("B") 300Distance from the center of gravity to center of rotation for boom (ft)("b") 9.5Weight of the structure (lb)(Z) 800Distance from the center of gravity to center of rotation for pillar (ft)("z") 9.5Thrust Load (lb)(A+B+Z) 6100Moment Load (ft*lbs)(Ab+Bb+Zz) 105450Recommended Bearing to safely operate (ROTEK Brand) A12-18E5

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Second Moment of Area – The capacity of a cross-section to resist bending.

Radius of Gyration (Area) – The distance from an axis at which the area of a body may be assumed to be concentrated and the second moment area of this configuration equal to the second moment area of the actual body about the same axis.

Section Modulus – The moment of inertia of the area of the cross section of a structural member divided by the distance from the center of gravity to the farthest point of the section, a measure of the flexural strength of the beam.

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*Note: P1 and P2 are positive in downward direction as shown in the figure and negative in upward direction.

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*Note: R1 and R2 are vertical end reactions at the left and right, respectively, and positive upward. Shear forces and deflections are positive in upward direction and negative in downward direction. All moments are positive when producing compression on the upper portion of the beam cross section. All slopes are positive when up and to the right.

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Deliverables/Timeline

September 2016

Pick project and assign groups (Completed)

Brainstorm ideas (Completed)

October 2016

Create proposal and presentation (Completed)

Revise proposal and create rough design (Completed)

November 2016

Finalize proposal and general design (Completed)

Detailed design of stabilizer jack (In progress)

Detailed design of pillar and boom (In progress)

December 2016

Write final proposal and present final presentation

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References

A. (n.d.). SIMPLY SUPPORTED STRUCTURAL BEAM WITH TWO

CONCENTRATED LOADS. Retrieved November 17, 2016, from

http://www.amesweb.info/StructuralBeamDeflection/SimpleBeamTwoConcentratedLoad

sAtAnyPoint.aspx

Engineering Data Manual - independencetube.com. (n.d.). Retrieved November 17, 2016,

from https://www.independencetube.com/downloads/Engineering_Brochure.pdf

T., B., & O. (2014). Home. Retrieved October 17, 2016, from

http://www.northerntool.com/shop/tools/product_200402703_200402703?

cm_mmc=Google-pla

Trailer Images. (n.d.). Retrieved October 17, 2016, from

http://www.mjtrailers.com.au/wb/pages/gallery/10-x-5-tandem-crane-trailer86.php