S T A N D A R D. Copyright American Society of Agricultural and Biological Engineers. All rights reserved.

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1 ANSI/ASAE S278.7 JUL03 (ISO ) Agricultural wheeled tractors and implements Threepointhitch couplers Part 1: U-frame coupler S T A N D A R D ASABE is a professional and technical organization, of members worldwide, who are dedicated to advancement of engineering applicable to agricultural, food, and biological systems. ASABE Standards are consensus documents developed and adopted by the American Society of Agricultural and Biological Engineers to meet standardization needs within the scope of the Society; principally agricultural field equipment, farmstead equipment, structures, soil and water resource management, turf and landscape equipment, forest engineering, food and process engineering, electric power applications, plant and animal environment, and waste management. NOTE: ASABE Standards, Engineering Practices, and Data are informational and advisory only. Their use by anyone engaged in industry or trade is entirely voluntary. The ASABE assumes no responsibility for results attributable to the application of ASABE Standards, Engineering Practices, and Data. Conformity does not ensure compliance with applicable ordinances, laws and regulations. Prospective users are responsible for protecting themselves against liability for infringement of patents. ASABE Standards, Engineering Practices, and Data initially approved prior to the society name change in July of 2005 are designated as ASAE, regardless of the revision approval date. Newly developed Standards, Engineering Practices and Data approved after July of 2005 are designated as ASABE. Standards designated as ANSI are American National Standards as are all ISO adoptions published by ASABE. Adoption as an American National Standard requires verification by ANSI that the requirements for due process, consensus, and other criteria for approval have been met by ASABE. Consensus is established when, in the judgment of the ANSI Board of Standards Review, substantial agreement has been reached by directly and materially affected interests. Substantial agreement means much more than a simple majority, but not necessarily unanimity. Consensus requires that all views and objections be considered, and that a concerted effort be made toward their resolution. CAUTION NOTICE: ASABE and ANSI standards may be revised or withdrawn at any time. Additionally, procedures of ASABE require that action be taken periodically to reaffirm, revise, or withdraw each standard. Copyright American Society of Agricultural and Biological Engineers. All rights reserved. ASABE, 2950 Niles Road, St. Joseph, MI , USA ph , fax , hq@asabe.org

2 ANSI/ASAE S278.7 JUL03 (ISO ) Approved September 2003 by American National Standards Institute Agricultural wheeled tractors and implements Threepoint hitch couplers Part 1: U-frame coupler Proposed by Advisory Engineering Committee of Farm and Industrial Equipment Institute; approved by ASAE Power and Machinery Division Technical Committee; adopted by ASAE December 1964; revised December 1965, June 1967; reconfirmed December 1971; revised April 1974, February 1975; corrected editorially April 1977; revised December 1978, March 1980; reconfirmed December 1984; revised editorially and reconfirmed December 1989; reaffirmed December 1994; revised editorially February 1995; reaffirmed December 1999, January 2001, December 2001, February Adoption with modification of ISO :1993 (E) and addition of ASAE Forward with deviations July Approved by ANSI September Forward 0.1 This ASAE document, ANSI/ASAE S278.7, Agricultural wheeled tractors and implements Three-point hitch couplers Part 1: U-frame coupler, is equivalent to ISO :1993 (E) except for the technical deviations as noted in the following forward sections. These technical deviations pertain to those provisions where harmonization could not be achieved between the ASAE and the International Standard. ISO :1993 does not contain some technical information that has been in the content of ASAE Standard S278. The responsible ASAE technical committee considered this information relevant and important to maintain in the document. 0.2 It has been found from experience that certain large implements used with dual rear tires and narrow crop row spacing require a special category narrow hitch. The difference between ISO and ASAE S278 is that the Special Hitch Coupler Categories (Category 3N and 4N) were omitted from ISO All the dimensions in ASAE S278.6 were exactly the same in ISO The ASAE Table 1 footnotes are noted in Section 4 of the ISO document. The ASAE Table 2 footnotes are listed in Section 5 of the ISO document. Dimension K1 in Table 2 of ASAE is listed in paragraph 5.4 of the ISO document. Dimension b2 shown in Table 2 of the ISO document was added to completely define the clearance envelope in this area (the ASAE document was incomplete in this regard). The PTO to hitch dimensions are not made in the ISO document, as they are in paragraph in ASAE, they are contained in the referenced ISO The responsible committee has reviewed the normative references listed in ISO and no additional documentation or deviations are required. 0.4 This standard had been approved as an American National Standard by ANSI (American National Standards Institute). ASAE technical content was provided as the original basis for this ISO standard. 0.5 ASAE technical deviations from ISO are: Special category 3N narrow hitch coupler. The dimensions of special category 3N shall be as follows: Dimension l 1,l 3,l 4,l 5,l 6 and l 7 in Table 1 shall be in accordance with Category 2. All other dimensions shall be in accordance with Category Dimensions l 1 and l 2 in Table 2 shall be in accordance with Category 2. All other dimensions shall be in accordance with Category Special category 4N narrow hitch coupler. The dimensions of special Category 4N shall be as follows: Dimension l 1,l 3,l 4,l 6 and l 7 in Table 1 shall be: l 1 = mm ( in.) l 3 = 858mm (33.78 in.) l 4 = 1174mm (46.22 in.) l 6 = 858mm (33.78 in.) l 7 = 1174mm (46.22 in.) All other dimensions shall be in accordance with Category Dimension l 1 in Table 2 shall be mm ( in.). Dimension l 2 in Table 2 shall be in accordance with Category 3. All other dimensions shall be in accordance with Category ANSIÕASAE S278.7 JUL03 ISO ASABE STANDARDS 2006

3 1 Scope This part of ISO specifies the essential dimensions for the attachment of three-point hitch implements to agricultural wheeled tractors equipped with a three-point free link hitch according to ISO 730-1, ISO or ISO , and a U-frame hitch coupler. NOTE 1 In general, the dimensions associated with the tractor and the implement for use with hitch couplers are the same as those for the three-point linkage specified in ISO 730-1, ISO or ISO , and those for the clearance zone specified in ISO ). The three-point hitch coupler systems constitute a special method of implement mounting. The hitch couplers are an additional component located between the three-point linkage and the implement, making it possible to hitch and unhitch from the operator s seat. Due to the special construction and function of hitch couplers, it may be necessary to vary the length of the links indicated in the referenced standards. This part of ISO applies to Categories 2, 3 and 4 of agricultural wheeled tractors as defined in ISO and ISO Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this part of ISO At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this part of ISO are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. Members of IEC and ISO maintain registers of currently valid International Standards. ISO 730-1: 1990, Agricultural wheeled tractors Rear-mounted threepoint linkage Part 1 Categories 1, 2 and 3. ISO 730-3: 1982, Agricultural wheeled tractors Three-point linkage Part 3: Category 4. ISO :1985, Agricultural wheeled tractors Front-mounted linkage and power take-off Part 2: Front linkage. 1) ISO 2332: 1983, Agricultural tractors and machinery Connections Clearance zone for the three-point linkage of implements. 3 Principle of frame coupler system A frame coupler system is a one-phase implement coupler where the three-point linkage of the tractor (see ISO 730-1, ISO or ISO ) is fitted with a U-frame and the implement has the provisions to be mounted to the frame. Hitching and unhitching can be operated from the tractor operator s seat. 4 Coupler dimensions Coupler dimensions shall comply with figure 1 and table The upper hook offset (dimension b 5 ) shall be not more than 15,75 mm greater or 6,35 mm less than the lower socket offset (dimension b 1 ) 4.2 The implement shall provide clearance when attached to the coupler to permit lowering all elements of the coupler 120,9 mm minimum for categories 2 and 3, and 146 mm minimum for category 4, to ensure satisfactory attachment and detachment of the implement from the coupler. 4.3 The upper hook of the quick coupler shall be at the centre of the lower sockets within 3 mm. 4.4 The lower implement attaching point on the quick-attaching coupler shall be located in the vertical position such that the lift range, power range and levelling adjustment, as specified in ISO and , are fulfilled. 4.5 Implement components, other than the hitch pins, that are in alignment with the lower socket width (dimension 1 ) shall not extend forward of the centreline of the lower socket for a distance of 203 mm above the lower socket. Components above this height, extending laterally more than 381 mm from the coupler centreline, shall not extend more than 25 mm forward of the vertical centreline through the upper hook opening. 4.6 The lower socket width ( 1 ) shall be maintained within the area defined by dimensions b 2, h 6, h 7 and b The lower link to coupler pins may be recessed to provide design freedom to obtain structural integrity in the coupler frame, resulting in a common dimension for l 3 and l 6, and l 4 and l 7, respectively. Figure 1 Coupler dimensions ASABE STANDARDS 2006 ANSIÕASAE S278.7 JUL03 ISO

4 Table 1 Coupler dimensions Dimensions in millimeters 5 Dimensions associated with implement Dimensions associated with the implement shall comply with figure 2 and table For implements with cantilever-mounted lower hitch pins, special quick coupler hitch pins shall be supplied to dimensions d 1, l 1, l 2 and d 2. Adapter bushings may be supplied which convert existing three-point hitch pins to dimensions d 1, l 1, l 2 and d 2 instead of special quick coupler hitch pins. For three-point hitch implements on which the lower hitch points consist of straddle-mounted pins, no additional thrust surfaces are required, providing the pin diameter and support dimensions conform to dimensions d 1, l 1, l 2 and b 1 The method used and dimensions related to attaching the pins or adaptor bushings to the implement are at the discretion of the implement manufacturer. 5.2 The lower implement attaching point on the quick attaching coupler shall be located in the vertical position such that the lift range, power range and levelling adjustment, as specified in ISO and ISO 730-3, are fulfilled. 5.3 Implement components, other than the hitch pins, that are in alignment with the lower socket width [dimension 1 (see figure 1 and table 1)] shall not extend forward of the centreline of the lower socket for a distance of 203 mm above the lower socket. Components above this height extending laterally more than 381 mm from the coupler centreline shall not extend more than 25 mm forward of the vertical centreline through the upper hook opening. 5.4 The adapter or lower hitch pin shall be in line within 0,015 mm per 1 mm of pin length. 5.5 The implement shall provide clearance when attached to the coupler to permit lowering all elements of the coupler 120,9 mm minimum for categories 2 and 3, and 146 mm minimum for category 4, for satisfactory attachment and detachment of the implement from the coupler. 5.6 The upper hook opening on the implement shall be at the centre of the lower hitch pin shoulders within 3 mm. 5.7 Provisions shall be made for adequate upper hook clearance in those implements which require landing or levelling. 6 Locking device A positive latch shall be provided to prevent an unintentional separation of the implement. 120 ANSIÕASAE S278.7 JUL03 ISO ASABE STANDARDS 2006

5 Figure 2 Dimensions associated with implement Table 2 Dimensions associated with implement Dimensions in millimeters ASABE STANDARDS 2006 ANSIÕASAE S278.7 JUL03 ISO

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