Question

hey everyone i would like to need a solution for 1.9D, 1.15D and 1.18D from chapter 1 book fundamentals of machine component design 5th edition

1.9D An incident occurred resulting in a worker’s hand being amputated in a machine called a “pallet notcher” that cuts notches in 2 in. 4 in. lumber (boards), used to build pallets. The boards move on a conveyor to the notcher where they drop into a covered area about four feet long. The covered area houses two sets of staggered rotating knives. The boards go through the first set of knives, notching one end, then through the second set, which notches the opposite end. At the time of the accident, Problems 31 c01.qxd 8/3/11 9:16 AM Page 31 the worker was collecting the notched wood from the exit area of the machine. He was pulling the boards outward as they exited the machine. He felt something hit his fingertip, and when he pulled back, his hand had been removed near the wrist. Additional facts in this accident include: (a) Prior to the day of the accident, the employee had not been stationed at the incident pallet notcher. (b) The incident pallet notcher machine was not the employee’s usual station. (c) The employee was working near the exit area of the notcher at the time of the accident. (d) The area where the boards exit the machine is approximately 7 in. high and 19 to 20 in. from the point of operation. This distance is easily reachable by an employee working at the machine exit. (OSHA report) (e) A piece of “hung” carpet located toward the exit of the machine hindered the visibility of the blades and allowed an employee to reach under it and access the blades. (f) The pallet notcher was not guarded to protect the employees from the point of operation. (OSHA report) (g) The employer knew that guarding was required and was aware that the pallet notcher was not guarded. (OSHA report) (h) The employee reportedly was not informed of the location of the blades for the incident machine. (i) At the time of the accident there was no warning label on the machine to alert the employee that a cutting blade was within his reach. (j) The employee was not instructed to use a pull stick to retrieve boards that do not exit the machine. (k) A “willful” citation (issued when the employer knowingly commits a violation) was proposed for a violation of 1910.212(a)(3)(ii). (OSHA report) Search the OSHA regulations at http://www.osha.gov and specifically review the section 29 CFR 1910.212(a)(3)(ii). Write a paragraph relating this section to the above incident. Also, list ways in which this accident could have been prevented.

1.15D D According to an OSHA director of field programs, a driller was in the process of raising the traveling block and the attached kelly and swivel assembly when an oil drilling rig accident occurred. During an oil drilling operation, an air-chugger winch cable was attached to the kelly pipe as a tag line to prevent it from swinging. Two of the rig hands were monitoring the kelly pipe as it was pulled out of the rat hole. The chain hand picked up the spinning chain and positioned himself near the drawworks drum as he waited for the kelly to be positioned over the hole. When he tossed the end of the spinning chain over his shoulder it became entangled in the fast line cable as the cable was spooled onto the drum. The spinning chain wrapped around the worker’s wrist and pulled him into the drum as the chain’s slack was drawn up. The spinning chain also struck the worker in the groin area and fractured his leg and severed his femoral artery. The driller stopped the drawworks before the worker was completely pulled into the drum encasement, but the worker was seriously injured. His leg was amputated and injuries to his hand resulted in a permanent disability. The drawworks drum was equipped with metal casing that enclosed the drum on the lower front, top, and sides. However, there was an opening of approximately 4' 3' to allow the fast line adequate clearances to spool back and forth onto the drum that has no barrier guard. (See Figure P1.15D.) Apparently, the drawworks drums used on oil well drilling sites were designed and constructed as described above without any barrier guard to protect workers in close proximity to the drawworks drum from the hazard of the ingoing nip point between the moving fast line and the drum. Search the OSHA regulations http://www.osha.gov and specifically review the regulation 29 CFR 1910.212(a)(1), General requirement for all machines. Write a paragraph explaining how this section would apply to the drum. Also, suggest a guard (design) that could have prevented this accident. Problems 35 4 3 Fast line cable

1.18D An incident occurred in which a cantilevered section of a walkway under demolition fell in a bagasse warehouse area at a sugar mill, resulting in the death of a worker positioned on top of the walkway. The incident walkway was constructed of two 2.625 in. by 10 in. steel C-channel main beams spaced three feet apart with metal floor grating welded to the top of the C-channel beams. The cantilevered walkway had welded-on hand rails and was approximately three ft in width, 11 ft in length and located at a height of 40 ft from ground level. This section weighed more than 800 lbs. The worker was positioned on the cantilevered portion of the walkway cutting through the floor grating of the walkway when the cantilevered walkway section unexpectedly gave way and fell to the area below. The demolition of the walkway left one section of the walkway cantilevered and supported by the metal floor grating and by an undersized weld. Demolition proceeded without an engineering study of the structural integrity of the bagasse walkway as well as an adequate plan for demolition. A proper engineering study of the structural integrity of the bagasse warehouse walkway as well as an adequate demolition plan in reasonable engineering probability would have prevented the accident. Search the OSHA regulation at http://www.osha.gov and review the sections 29 CFR 1926.501(a)(2) and 29 CFR 1926.850(a). Write a paragraph relating each section to the above incident and describe how following the regulations would have reduced the risk to employees.

Answer 1

Analysis:

1. The Regulations (Standards - 29 CFR) - Table of Contents – shows:
• Part Number: 1910
• Part Title: Occupational Safety and Health Standards
• Subpart: O
• Subpart Title: Machinery and Machine Guarding
• Standard Number: 1910.212
• Title: General requirements for all machines.
2. Specifically for 29 CFR 1910.212(a): Machine guarding.
1910.212(a)(1)
Types of guarding. One or more methods of machine guarding shall be provided to
protect the operator and other employees in the machine area from hazards such as
those created by point of operation, ingoing nip points, rotating parts, flying chips and
sparks. Examples of guarding methods are-barrier guards, two-hand tripping devices,
electronic safety devices, etc.
1910.212(a)(2)
General requirements for machine guards. Guards shall be affixed to the machine where
possible and secured elsewhere if for any reason attachment to the machine is not
possible. The guard shall be such that it does not offer an accident hazard in itself.
1910.212(a)(3)
Point of operation guarding.
1910.212(a)(3)(i)
Point of operation is the area on a machine where work is actually performed upon the
material being processed.
1910.212(a)(3)(ii)
The point of operation of machines whose operation exposes an employee to injury,
shall be guarded. The guarding device shall be in conformity with any appropriate
standards therefore, or, in the absence of applicable specific standards, shall be so
designed and constructed as to prevent the operator from having any part of his body
in the danger zone during the operating cycle.
1910.212(a)(3)(iii)
Special handtools for placing and removing material shall be such as to permit easy
handling of material without the operator placing a hand in the danger zone. Such tools
shall not be in lieu of other guarding required by this section, but can only be used to
supplement protection provided.

3. This accident could have been prevented if (a) the machine had been properly
guarded, (b) a warning label was visible by employees working at the machine exit,
and/or (c) the employer had been properly trained and instructed as to the location of
the blades.
Comments:
1. There was no guard on the machine’s exit to prevent an employee from
reaching the blades within the machine.
2. By leaving the machine unguarded, the employer allowed their employees to be
at serious risk of injury on the unseen yet reachable blades.
3. The employer failed to provide a safe workplace.