75 and the opposite ends of the shock absorbers are connected to a lower support member 24a of the frame 13 it can thus be seen that the tension exerted by spring 71 on the cable 60 is transferred around the sheaves 65 63 and 61 so that the tension in cable 60 tends to urge the packer head 22 toward the end of the cover adjacent the feed spout 17 spring 71 exerts a resilient force on the packer head 22 at all times and the shock absorbers 76 serves to dampen movement during return of the packer head 22 to its original position the arms 43 and 44 of the cover are pivotally mounted to the rear upright legs 25 each of the legs 25 has a pair of ears 80 80 on opposite sides thereof which receive a pivot lug 81 and 82 respectively the pivot lug 81 is on arm 43 and the lug 82 is on arm 44 the ears 80 80 can be adjustably mounted for vertical adjustment along the legs 25 to provide for mounting the cover correctly and making for adjustments that might be necessary to obtain satisfactory operation the arms 43 and 44 extend on the opposite side of the pivot pins 81a and 82a from the main direction of extension of the cover see fig3 and 4 and on the outwardly extending end portions indicated at 43b and 44b there.