Oil filter wrench

A strap wrench especially designed for removing oil filters. The strap is retained at the end of the wrench by a retainer structure so that the strap is readily tightened on the oil filter and can be used to loosen the oil filter with minimum torque applied to the handle of the wrench.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The invention is directed to a strap wrench and, more particularly, to a 
strap wrench especially designed for removing oil filters on cars. 
2. Description of the Prior Art 
U.S. Pat. No. 4,145,938 is directed to a strap wrench that uses a specially 
designed camming surface to anchor the strap in position on the workpiece. 
U.S. Pat. No. 1,525,358 is directed to a strap wrench similar in structure 
to that of the above patent. 
Australian Pat. No. 7712/32 discloses a strap wrench using a relatively 
flat end with a strap retainer structure holding the two ends of the strap 
on the wrench handle. 
U.S. Pat. Nos. 689,325 and 840,496 disclose strap wrenches that use a ring 
structure to fasten the one end of the strap to the body of the wrenches. 
SUMMARY OF THE INVENTION 
The strap wrench has the one end of the strap fastened to the wrench handle 
by way of a ring structure. A retainer loop is positioned on the wrench 
handle and the strap passes both ways through the retainer loop to form 
the strap loop that engages the workpiece. The flat end of the wrench body 
and a corner thereof assists in preventing the strap from slipping out of 
position. The other end of the strap is also positioned within the ring 
structure to assist in holding the strap in position on the workpiece.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
The strap wrench 2 is best shown in FIG. 1. The wrench is composed 
primarily of a strap 4 and a handle portion 6. The handle portion is 
composed of a handle member 8 and a body member 10 which are normally 
molded from plastic as an integral unit. The body member 10 is slightly 
off-set from the longitudinal axis of the handle member 8. 
The body member has a flat end 12 at the end of the body opposite from 
where the body member is connected to the handle member. Adjacent to this 
end 12 and on the upper part of the body member there is a surface 14 on 
which the strap is positioned and a retainer loop structure 16 is mounted 
on this flat surface 14 adjacent to the end 12. A corner 13 is provided 
adjacent end 12. 
At the point where the body member and handle member blend together, there 
is provided a groove 18. This groove extends across the width of the body 
member and is just below the flat surface 14 of the body member. A ring or 
link structure 20 is positioned in the groove. As best seen in FIG. 2, the 
ring 20 has one side 21 thereof slipped into the groove 18. Two adjacent 
sides extend parallel with the handle member of the strap wrench and the 
side 22 of the ring structure opposite from the side 21 in groove 18 is 
positioned above the flat surface 14. This side 22 in FIG. 2 has one end 
of the strap fastened thereto. The one end of the strap is looped about 
itself and is stitched, sonic welded or by other means fastened into 
position so that the one end of the strap wrench is formed into a loop 
fastening around element 22 and due to the stitching, etc. forms a 
permanent closed loop. The end of the strap is passed around a sufficient 
portion of the body of the strap so that both the end of the strap 24 and 
the portion 26 of the body of the strap to which it is fastened thereto 
both fit within the retainer loop structure 16, but the end 24 does not 
pass beyond the end of the retainer loop. 
The remaining portion of the strap 4 is then formed in a large loop 28 and 
the opposite end 30 of the strap then passes through the retainer loop 
structure under the stitched looped end of the strap and it further passes 
within ring structure 20 and out along the top side of the handle 8 as 
best shown in FIG. 1. By pulling on the end 30 of the strap, the size of 
the loop 28 can be adjusted. When the strap is pulled tight around some 
object, the ring structure 20 pulls down in the direction towards the flat 
surface 14 and, thus, a pinching action occurs on the end 30 of the strap 
to frictionally hold it between the flat surface 14 and the closed loop 
stitched in the opposite end of the strap. 
When the strap wrench is in use, it is so positioned on an object so that 
the strap wrench would be pulled in the direction of the arrow 32 which 
then pushes the flat surface 12 tight up against the strap 4 and cause 
corner 13 to indent the strap and this provides a very positive clamping 
action against the strap 4 to prevent the strap from slipping on the 
material being held within the loop 28 of the strap. The corner 13 and the 
flat surface 12 function to compress the gap in the loop, therefore 
shortening the length of the strap and causing increased tension in the 
strap. It has been found that once the strap is in position and has been 
used to loosen or tighten an object the ring structure 20 must be pushed 
upward away from the flat surface 14 in order to release the strap end 30. 
The strap wrench described above is very economical to manufacture since it 
is composed of basically three parts. The one part being a very simple 
molded plastic handle part to which is positioned the second part which is 
the ring structure 20 and then these two elements retain a strap structure 
4 in the loop configuration shown in FIG. 1. Through the use of the 
combination action of the ring structure, the retainer loop structure, the 
flat surface 12 and corner 13, the abovedescribed strap wrench will 
provide a very firm, non-slipping grip on any object so that it may be 
readily unfastened or tightened. The abovedescribed strap wrench is 
particularly useful for placing and removing oil filters from automobiles.