Trailer prop operating structure

Claim 2

In a trailer prop, a jackscrew and a nut arrangement for raising and lowering the prop comprising: an immovable vertically extending jackscrew having thread means, said thread means of said jackscrew being of double start thread construction including a pair of vertically alternating helical thread elements, each thread element having a downward facing lower thread face being directed inwardly generally perpendicular to the vertical axis of the jackscrew, a nut on the jackscrew having thread means having an upward facing thread face complemental to and for engagement with said lower thread face of each thread element of said jackscrew for lifting the prop, each thread element of said jackscrew having an upward facing upper thread face at less than 90* to the vErtical axis of the jackscrew and directed upwardly in sloping fashion toward the vertical axis of the jackscrew, and said thread means of said nut having a downward facing thread face complemental to and for engagement with said upper thread face of each thread element of said jackscrew for retracting the prop and to eliminate downward jiggling of the nut on the jackscrew.

Claim 3

The invention according to claim 1, and said lower thread face of said jackscrew being disposed between 1* and 10* from the horizontal.

Claim 4

The invention according to claim 1, and said upper thread face of said jackscrew being disposed between 10* and 45* from the horizontal.

Claim 5

The invention according to claim 1, and the vertical height of each thread element of said jackscrew being less than the vertical distance of the space between a pair of successive thread means of said nut receiving such thread element of said jackscrew to provide a clearance between one of the faces of each thread element of said jackscrew and said thread means of the nut when the other faces of each thread element of said jackscrew and said nut are in engagement with one another so as to aid in efficient lifting and retracting of the trailer prop.

Claim 6

The invention according to claim 1, and said lower face of said jackscrew being between substantially 1* and 10* from the horizontal and the upper face of said jackscrew being between substantially 10* and 45* from the horizontal.

Claim 7

The invention according to claim 5, and the vertical height of each thread element of said jackscrew being less than the vertical distance of the space between a pair of successive thread means of said nut receiving such thread element of said jackscrew to provide a clearance between one of the faces of each thread element of said jackscrew and the thread means of the nut when the other faces of each thread element of said jackscrew and the thread means of the nut are in engagement with one another to aid in efficient lifting and retracting of the trailer prop.

Claim 8

A telescoping trailer prop including a fixed outer telescoping part and a movable inner telescoping part comprising: a jackscrew fixed with the immobile telescoping part, a nut disposed about the jackscrew and fixed with the movable telescoping part, said jackscrew having thread means, said thread means of said jackscrew being of double start thread construction including a pair of vertically alternating helical thread elements, each thread element, including a downward facing lower thread face being directed generally perpendicular to the vertical axis of the jackscrew, said nut having thread means including a first nut face having contouring for complemental engagement with the lower face of each thread element of said jackscrew for moving the inner telescoping part outward for lifting the prop, each thread element of said jackscrew having an upward facing upper face at less than 90* to the vertical axis of the jackscrew and directed upwardly in sloping fashion toward the vertical axis of the jackscrew, said thread means of said nut including a second nut face having contouring for complemental engagement with the upper face of each thread element of said jackscrew for moving the inner telescoping part inward for retracting the jackscrew and to prevent downward jiggling of the inner telescoping part during the retraction thereof, and said lower face of each thread element of said jackscrew being between substantially 1* and 10* from the horizontal and the upper face of each thread element of said jackscrew being between substantially 10* and 45* from the horizontal.

Claim 9

A telescoping trailer prop including a fixed outer telescoping part and a movable inner telescoping part comprising: a jackscrew fixed with the immobile telescoping part, a nut disposed about the jackscrew and fixed with the movable telescoping part, said jackscrew having thread means, said thread means of said jackscrew being of double start thread construction including a pair of vertically alternating helical thread elements, each thread element, including a downward facing lower thread face being directed generally perpendicular to the vertical axis of the jackscrew, said nut having thread means including a first nut face having contouring for complemental engagement with the lower face of each thread element of said jackscrew for moving the inner telescoping part outward for lifting the prop, each thread element of said jackscrew having an upward facing upper face at less than 90* to the vertical axis of the jackscrew and directed upwardly in sloping fashion toward the vertical axis of the jackscrew, said thread means of said nut including a second nut face having contouring for complemental engagement with the upper face of each thread element of said jackscrew for moving the inner telescoping part inward for retracting the jackscrew and to prevent downward jiggling of the inner telescoping part during the retraction thereof, and said lower face of each thread element of said jackscrew being between substantially 1* and 10* from the horizontal and the upper face of each thread element of said jackscrew being between substantially 10* and 45* from the horizontal.

Claim 10

The invention according to claim 7, and the vertical height of each thread element of said jackscrew being less than the vertical distance of the space between a pair of successive thread means of said nut receiving such thread element of said jackscrew to provide a clearance between one of the faces of each thread element of said jackscrew and the thread means of said nut when the other faces of each thread element of said jackscrew and the thread means of said nut are in engagement with one another to aid in efficient lifting and retracting of the trailer prop.