Assertion: slide fastener's pair | /r/CapableOf | serve to prevent the front end portion
Facets:
value: from removing off the vertical groove
type: TRANSITIVE-OBJECT
Source sentences:
text: The downwardly bent small-width front end portion 9 of the locking leaf spring 2 has in its front surface a vertical front recess 27 for reinforcing and in its opposite side surfaces a pair of side recesses -28 which serves to prevent the front end portion 9 from removing off the vertical groove 21 of the guide post 6.