定价： 646元 加购物车

定价： 646元 加购物车

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4.1 It may be desirable at times to provide hand holes in corrugated boxes. Package designers use hand holes to solve ergonomic and handling problems associated with large or awkward containers. This guide provides an aid for proper hand hole design and use.4.1.1 Boxes for handling by a single person.4.1.2 Boxes that are too large or awkward to be handled well by a single person (4.4.1).4.2 Ergonomics: 4.2.1 In studying and applying ergonomic principles, of primary concern is the need to provide a safe work environment for material handlers who may be required to lift or transport packages. A safe work environment is difficult to define and varies with the package in question. Several ergonomic safety issues involve repetitive motions and spine loading in the lifting process. Other issues involve finger and foot protection.4.2.2 In distribution centers or warehouses, low back disorders have been identified as areas of elevated risk. Low back problems continue to represent the most common and costly musculoskeletal disorders in the work place.44.2.3 One method used to reduce the concern of distance of lift (spinal loading) is to bring the reach of the material handler's hands closer to the body. With large or awkward boxes, placing hand holes in a more advantageous position can solve this problem.4.2.4 Maximum weight for lifting is not generally specified by safety organizations. However, when considerations of repetition, movement, and other ergonomics are taken into account, a typical maximum load per single person is often limited to 40 to 50 lb per package.4.3 NIOSH: 4.3.1 The National Institute for Occupational Safety and Health (NIOSH) has published Work Practices Guide for Manual Lifting.5 This document may be of assistance in developing proper hand holes and their placement for a specific package.4.3.2 Hand holes for single person box handling are generally intended for vertical symmetric lifting with some rotation and is limited to a few steps. Use of hand holes to lift with one hand, push a box, or pull a box are not recommended practices.4.3.3 Actual maximum acceptable load for a single person lift depends on box weight, size, lift frequency and distance of movement. Maximum weight and size limits can be estimated using the NIOSH equations.4.4 Other Box Apertures – Improper Use as Hand Holes: 4.4.1 Some hand holes are intended for hand gripping to facilitate moving or turning a heavy box but are not intended for lifting.4.4.2 Not all box apertures are intended to be used as hand holes. These apertures may be intended for ventilation, inspection, adjustment of contents or other uses. These other apertures are not intended for use in manipulating boxes and it is improper to use these apertures as hand holes.4.4.3 Examples of typical hand holes are shown in Fig. 1. Use of hand holes and associated cautions should be agreed upon between the supplier and the user.FIG. 1 Common Hand Hole Types4.4.4 Since all end use conditions and requirements cannot be foreseen and since designing for worst case scenario for all applications is prohibitively expensive, designers should follow best practices. The prudent designer will consider product and package weight when deciding the proper use of a hand hole.1.1 This standard provides guidelines for designing pre-cut apertures intended for use as hand holes in corrugated boxes during manual handling of boxed cargo.1.2 Limitations—This standard offers guidance for package development and for subsequent testing of boxes to measure performance. It is not intended to provide specific information on the design of hand holes.1.3 The values stated in inch-pound units are to be regarded as the standard. The SI units are for information only.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use..1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

定价： 646元 加购物车

定价： 571元 加购物车

定价： 515元 加购物车

定价： 515元 加购物车

定价： 515元 加购物车

定价： 712元 加购物车

定价： 646元 加购物车

This specification establishes the requirements for parts intended for aerospace use and machined from polychlorotrifluoroethylene (PCTFE) homopolymers. This specification, however, does not cover parts machined from PCTFE copolymer, PCTFE film or tape, or modified PCTFE. Material covered by this specification is on four types, differentiated based on intended uses and exposures: Types I (high service pressure) and II (low service pressure) for use in air and oxygen media, Type II for use in inert and reactive media, and Type IV for use in other media. The parts shall be manufactured from virgin, unplasticized, pure PCTFE homopolymer, and the use of recycled polymer or regrind shall be prohibited. The base material shall be free of defects and contaminants. The finished parts shall be white or gray in color with a natural translucent appearance, and shall be free of voids, scratches, fissures, inclusions, or entrapped air bubbles. Tests for specific gravity, melting point, tensile strength and elongation, deformation under load, zero strength time, mechanical impact (in ambient liquid oxygen and pressurized liquid and gaseous oxygen environments), and dimensional stability shall be performed and shall conform to the requirements specified.1.1 This specification is intended to be a means of calling out finished machined parts ready for aerospace use. Such parts may also find use in selected commercial applications where there are clear benefits derived from the use of parts with high molecular weight, good molecular weight retention during processing, dimensional stability, controlled crystallinity, and tightly controlled engineering tolerances.1.2 This specification establishes requirements for parts machined from virgin, unplasticized, 100 % polychlorotrifluoroethylene (PCTFE) homopolymers.1.3 This specification does not cover parts machined from PCTFE copolymers, PCTFE film or tape less than 0.25-mm (0.010-in.) thick, or modified PCTFE (containing pigments or plasticizers).1.4 This specification does not allow parts containing recycled material.1.5 The specification does not cover PCTFE parts intended for general use applications, in which control of dimensional stability, molecular weight, and crystallinity are not as important. For machined PCTFE parts intended for general use, use Specification D7211.1.6 This specification classifies parts into three classes based upon intended uses and exposures: oxygen-containing media, reactive media, and inert media.1.7 Application—PCTFE components covered by this specification are virgin, 100 % PCTFE resin, free of plasticizers and other additives. The components are combustion resistant in oxygen, dimensionally stable, and meet other specific physical characteristics appropriate for their end use. They are used in valves, regulators, and other devices in oxygen, air, helium, nitrogen, hydrogen, ammonia, and other aerospace media systems. The components typically are used as valve seats, o-rings, seals, and gaskets. They are removed and replaced during normal maintenance procedures. The components provide reliable sealing surfaces resulting in proper closure of valves and related devices and no leakage from the system into the environment. They will experience static mechanical loading, cyclic mechanical loading, temperatures ranging from cryogenic to 71°C (160°F), and pressures up to 68.9 MPa (10,000, psig) for oxygen and air media, and 103.4 MPa (15,000 psig) for inert media.1.8 The values stated in SI units are to be regarded as standard. The values in parentheses are for information only.1.9 The following precautionary caveat pertains only to the test methods portion, Section 13, of this specification: This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.NOTE 1: There is no known ISO equivalent to this standard.1.10 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

定价： 590元 加购物车

定价： 646元 加购物车

定价： 590元 加购物车

定价： 590元 加购物车

This specification addresses the physical properties of copolymers of chlorotrifluoroethylene, perfluoroalkoxy, and tetrafluoroethylene that are suitable for extrusion, compression, and injection molding. It does not cover blended and recycled materials. Covered here is one type of fluoropolymer that is supplied in pellet form and classified according to their melting points, while the resins of each type are divided into four grades according to their melt flow rates. The materials shall be sampled in accordance with an adequate statistical sampling procedure and shall conform to specific gravity, melting point, flow rate, elongation, and tensile strength requirements when tested by the procedures itemized herein.1.1 This specification covers copolymers of chlorotrifluoroethylene, perfluoroalkoxy, and tetrafluoroethylene and are suitable for extrusion, compression, and injection molding.1.2 This specification does not cover blended materials and does not cover recycled materials.1.3 The values stated in SI units as detailed in IEEE/ASTM SI-10 are to be regarded as the standard. The values given in parentheses are for information only.1.4 The following safety hazards caveat pertains only to the test method portion, Section 11, of this specification. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.NOTE 1: Although this classification system and ISO 20568-1 and ISO 20568-2 differ in approach or detail, data obtained using either are technically equivalent.1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

定价： 515元 加购物车