is concave as shown in addition the side of the elastomeric block 48 bonded to the first mounting plate 45 is angled with respect to the side of the elastomeric block 48 bonded to the second mounting plate 46 so that the first mounting plate 45 is angled with respect to the second mounting plate 46 this angled relationship provides a desired angled relationship between the closure wing 43 and the rail 51 without requiring shims to provide such an angle the casting of the elastomer block 48 can provide any desired angle the elastomer block 48 provides elastic movement in many directions instead of in the single direction provided by a metal spring and pivot the design is symmetrical so that there is no left or right no top or bottom only a front and back since each closure wing 43 has a elastomeric closure spring 44 for each harvester 30 there are a plurality of elastomeric closure springs 44 requiring a plurality of first mounting plates 45 a plurality of second mounting plates 46 and a plurality of elastomeric blocks 48 wherein each elastomeric block 48 is bonded between a first mounting plate 45 and a second mounting plate 46 in operation an operator steers the harvester 30 so that grape or other plants to be harvested are placed between the closure wings 43 as the plant enters between the two rows of closure wings 43 the elastomer closure springs 44 flex allowing the plant to pass between the two rows of closure wings.