Earth-moving machinery - Coupling of attachments to skid steer loaders
1 Scope
This document provides for the interchangeability of attachments on skid steer loaders by establishing requirements for the quick coupler system including dimensional limits for the attachment mounting frame.
This document applies to skid steer loaders as defined in ISO 6165.
Note 1: Skid steer loaders can use other styles of quick couplers but the coupler would not be interchangeable with attachments designed to comply with this document.
Note 2: The requirements of this document can be applied to quick couplers used on other compact machines.
Note 3: Quick couplers used on small skid steer loaders and some compact tool carriers can have a different width requirement than provided in this document. See Annex B.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 38181-2019 Earth-moving machinery - Quick couplers - Safety (ISO 13031:2016, IDT)
ISO 6165 Earth-moving machinery - Basic types - Identification and terms and definitions
Note: GB/T 8498-2017, Earth-moving machinery - Basic types - Identification and terms and definitions (ISO 6165:2012, IDT)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 6165 and the following apply.
3.1
attachment
assembly of components that can be mounted onto the skid steer loader lift arm for specific use
[SOURCE: GB/T 18577.2-2008, 3.5, modified]
3.2
quick coupler
device mounted on a skid steer loader to allow quick interchange of attachments (3.1)
[SOURCE: GB/T 38181-2019, 3.1, modified]
3.3
attachment mounting frame
attachment component that facilitates the quick mounting and removal of an attachment (3.1) to the quick coupler (3.2)
3.4
engagement system
mechanical system of the quick coupler (3.2) which engages with the attachment mounting frame (3.3) and retains the attachment (3.1) in its working position
[SOURCE: GB/T 38181-2019, 3.2, modified]
3.4.1
wedge-type engagement system
engagement system (3.4) of at least two interconnecting parts which engage with one another in a wedge action whereby the combination of the wedge angle and the friction coefficient counteract the tendency of the working forces (3.5) to cause disengagement
[SOURCE: GB/T 38181-2019, 3.2.4, modified]
3.5
working forces
forces created by the working operations of the skid steer loader and attachments (3.1) that act upon the quick coupler (3.2) during intended use and reasonably foreseeable misuse
[SOURCE: GB/T 38181-2019, 3.3.1, modified]
4 General requirements
The quick coupler system shall be designed in accordance with Clause 5 and the following, using the attachment mounting frame dimensions given in Clause 6 as guidance.
a) The dimensions of the quick coupler should be such that the interface of the vertical face of the quick coupler and the attachment mounting frame does not result in surface-to-surface contact when engaged and locked together. This connection shall result in contact in each of the three zones of interface contact surface between the quick coupler and the attachment mounting frame during all operating modes of the loader and attachment. The design of the quick coupler may allow a gap between the quick coupler and the attachment mounting frame. See Figure 1.
b) See Figure 5. The quick coupler shall not protrude
——above surface A,
——forward of surface B, or
——below surface C.
Note: Some attachments could require added support structure to the attachment mounting frame between surfaces A and B.
c) The linkage of the quick coupler to the loader lift arms should provide a minimum of 5° rollback beyond vertical of the quick coupler towards the loader with the lift arms in their lowest position. The amount of rollback may be less for quick couplers used on smaller skid steer loaders, compact tool carriers and other compact equipment.
5 Safety requirements
A skid steer loader quick coupler shall comply with the requirements of GB/T 38181-2019, 4.1, for a wedge-type engagement system.
Note: A skid steer quick coupler is a combination of two different wedge-type engagement systems. See Annex A for further information on how these different wedge-type engagement systems apply to the skid steer quick coupler system.
The wedges/pins of the quick coupler shall engage the attachment mounting frame at the wedge/pin contact surfaces (see Figure 1) when the attachment is properly connected.
The locking system shall prevent retraction of the wedges/pins from attachment mounting frame during operation of the loader with the attachment when the working forces are pulling the attachment mounting frame in a direction away from the quick coupler (e.g. forcing a bucket against the ground pushing upward on the bottom of the bucket, loader traveling rearward with a scarifier attachment). See Figure A.2.
6 Attachment mounting frame dimensions
The dimensions for the attachment mounting frame shall be as shown in Figures 2 to 5. The attachment shall only have components outside the described space.
Some attachments can require added support structure to the attachment mounting frame between surfaces A and B in Figure 5. See Figure 2 b) and 3 b) for dimensions of area that centre support structure may be allowed.
