Semitrailer sliding tandem pin puller

A pin puller, comprising a spring, a clamp, and a handle, which is used to pull the pins on the sliding tandem of a semitrailer. The pin puller may also be provided with a guard and a wire which has a flag on one end. When the pins are pulled, the flag will stick out so that the driver can see the flag emerge beyond the side of the semitrailer.

SUMMARY AND BACKGROUND OF THE INVENTION 
Truck semi-trailers are equipped with a sliding tandem frame which is slid 
to adjust the weight distribution of the cargo inside the semi-trailer. At 
the point on the semitrailer where the tandem wheels slide back and forth, 
there are four pins inside. These pins fit through openings in the 
flange-like frame on the side of the trailer box and extend to openings in 
the tandem frame. A handle is positioned underneath the pins and extending 
toward the outside of the trailer. The pins come in when the handle is 
pulled and the trailer frame slides on the tandem frame. In order for the 
tandem frame to slide, the holes must be lined up and the pins pulled out. 
If the pins are not lined up into the holes of the frame, the pins will 
stick and be hard to pull out. In this case, the semitrailer must be 
rocked back and forth until the pins line up. Usually the pins are pulled 
manually and generally two people are needed to do the job. The only known 
prior art device for pulling pins is a mule, which is air-operated and 
permanently affixed. 
The present invention is a pin puller which has a spring which attaches to 
the aforementioned frame handle, a clamp which fits onto the edge of the 
trailer, and a handle which tightens the clamp. The object of the 
invention is to provide an easier method for pulling the pins, applying 
pressure on the pins so that when the tandem is rocked, the pins will line 
up more readily.

DESCRIPTION OF THE INVENTION 
The pin puller comprises a spring 1, a clamp 2, and a handle 3. The spring 
1 is preferably the 1/8 inch wire size with 80 pull, and is approximately 
eleven inches long. The spring 1 has a ring 4 at one end which attaches 
around the end of the handle 25 of the semitrailer frame,and has a hook 5 
at the opposite end which attaches to the clamp 2 through an opening 7 in 
the clamp 2. 
The clamp 2 is made of metal, preferably malleable iron. The clamp 2 
comprises a first piece 11 which is approximately 21/2 inches long, and a 
second piece 12 which is L-shaped and is welded to the first piece 11. The 
opening 7 through which the hook 5 of spring 1 fits is located on this 
part of first piece 11 below second piece 12. The L-shaped second piece 12 
is positioned so that the short side is perpendicular to the first piece 
11 and the long side is parallel to first piece 11, thus leaving a 
U-shaped space 14 approximately 3/8 inch across between first piece 11 and 
the parallel portion of second piece 12. The clamp 2 fits onto the edge of 
the semitrailer such that the semitrailer edge is fitted into the U-shaped 
space 14 with first piece 11 to the inside and second piece 12 underneath 
and to the outside. There is a threaded opening 15 formed into the long 
side of second piece 12. 
The handle 3 is fitted into opening 15. The handle 3 includes a threaded 
locking stud 17 which is screwed into opening 15 and which is 
perpendicular to the handle 3. The sides of handle 3 are flattened. The 
handle 3 is preferably made of metal, and is used to tighten the clamp 2 
onto the semitrailer frame. 
To use the device, the ring end 4 of the spring 1 is slid on over the end 
of semitrailer frame handle 25, the spring 1 is extended, and the clamp 2 
is hooked into position on the edge of the semitrailer frame. Extending 
the spring 1 applies pressure on the pins so that when the tandem frame is 
rocked, the pins will line up. 
Optional features may be added. A guard 21 made of PVC plastic, hollow and 
generally tubular but of slightly greater diameter at one end, can be fit 
over the spring 1. A wire 22 can be tied around the spring 1, then be 
passed through an eye 23 formed into the guard 21 and continue to extend 
along the outside of the guard 21. The wire 22 has a small plastic flag 
24, preferably yellow in color, at its distal end. When the spring 1 pulls 
the pins, the flag 24 will stick out so that the driver can see the flag 
24 emerge beyond the side of the semitrailer.