of the locking apparatus 20 due to the lower shear pin 34 support linkage is also maintained by the fishing neck dog 40 engagement with the detent channel 42 in the lock assembly sleeve 23 and the abutment of shoulders 82 and 90 on the spring sleeve and control dog housing respectively furthermore the control dog housing 66 is biased downward against the lock assembly sleeve 23 while the spring mandrel 16 connected by lower shear pin 34 to the packing mandrel 22 is biased upward both due to the urging of the compression spring 17 consequently when the control dogs 38 are released from the control dog housing 66 the upward bias of the spring mandrel 16 lifts the packing mandrel 22 while holding the lock assembly sleeve 23 down thereby causing a compressive closure between the packing mandrel 22 and the locking dog cage 52 shown by fig3 as the ramped shoulder 88 of the packing mandrel 22 engages with the locking dogs 50 the locking dogs are radially displaced into a dog receptacle channel 102 in the landing nipple 100 component of the well fluid production tube thereby securing the locking apparatus 20 to the landing nipple 100 by a mechanical interference as is illustrated by fig3 and 4 continued expansion of the spring 17 by compression of the packing ring 28 displaces the spring mandrel 16 relative to the control dog housing 66 until the support land 92 portion of the spring mandrel 16 passes from under the fishing neck dog 40 as the ramped shoulder 82 passes the fishing neck dog 40 fig6 the dog 40 drops from.