Apparatus for extracting and installing a hinge pin

A bar has a slot with the shank of a pin of a hinge therein. The slotted bar is connected to one end of a force transfer bar, the other end being connected to one end of a lever bar. Bottom surfaces of the slotted bar and the force transfer bar subtend an obtuse angle. Top surfaces of the force transfer bar and the lever bar subtend an obtuse angle. An anvil is connected to the lever bar. When the pin is being installed in the hinge, a retention bar bears against the top of the head of the pin. Force from an air hammer is transferred via the anvil through the lever, transfer and retention bars to the top of the head of the pin. When the pin is being extracted, the force is transferred through the slotted bar to the bottom of the head.

BACKGROUND OF THE INVENTION 
1. Field of Invention 
This invention is in the field of power tool accessories and methods 
therefor and, more particularly, is an accessory to an air hammer that is 
used for alternatively installing and extracting a hinge pin in a hinge 
and method therefor. 
2. Description of the Prior Art 
In removing a door of an automobile, a mechanic uses a hammer and a punch 
to extract a pin from a hinge of the door. The mechanic has access to the 
pin when he opens the door and positions himself in a confined area 
between the open door and the inside of the automobile. Additionally, the 
pin is in a portion of the hinge between a door jamb and the door. The 
space between the door jamb and the door is usually too small for the 
mechanic to make satisfactory use of the hammer. 
The pin may be rusted, thereby making the extraction either difficult or 
impossible. However, under the best of conditions, the extraction is time 
consuming. 
Many of the difficulties encountered in the removal of the door are 
encountered with the installation of the door. During the installation, 
the mechanic is restricted to the confined area. The only substantive 
difference is that the punch is positioned for inserting the pin instead 
of removing it. Heretofore, there has not been a way to utilize a power 
tool to reduce the time for the extracting and the installation that is 
easily used in the area where the hinge is located. 
SUMMARY OF THE INVENTION 
An object of the present invention is to provide an accessory to an air 
hammer that is operable to alternatively remove and insert a pin of a 
hinge and method therefor. 
BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENT 
A flat metal bar has a slot at its distal end. The proximal end of the 
slotted bar is connected to one end of a force transfer bar, the other end 
being connected to one end of a lever bar. Bottom surfaces of the slotted 
bar and the force transfer bar subtend an obtuse angle. Top surfaces of 
the force transfer bar and the lever bar subtend an obtuse angle. A 
cylindrical anvil is connected to the lever bar with its axis 
perpendicular to the top surface thereof. 
The invention provides a simple, economical accessory to an air hammer that 
is alternatively useable to install and extract a pin of a hinge located 
in an area where a hand tool cannot be satisfactorily used. 
Other objects, features and advantages of the invention will be apparent 
from the following description of the preferred embodiment as illustrated 
in the accompanying drawing.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
As shown in FIGS. 1-3, an accessory to an air hammer includes a flat bar 10 
(FIGS. 1 and 2) that has a distal end with a slot 12 therein. An inner 
section 14 of slot 12 has a width substantially equal to the diameter of 
the shank 16 of a pin 18 that is alternatively installed in or extracted 
from a hinge. 
An end 20 of section 14 has a radius of curvature substantially equal to 
the radius of shank 16. When pin 18 is either being extracted or being 
installed, bar 10 is positioned with shank 16 within section 14 in an 
abutting relationship with end 20. 
When pin 18 is being installed, the bottom of the head 22 (FIG. 3) of pin 
18 is maintained against a top surface 24T (FIG. 1) of bar 10 in a manner 
explained hereinafter. An outer section 26 (FIG. 2) of slot 12 is of a 
width greater than the width of section 14 to facilitate an initial 
capturing of shank 16 within slot 12. 
Bar 10 has a threaded hole 28 therethrough. A retention bar 30, having 
substantially the same length, width and thickness as bar 10, has a hole 
32 therethrough. When bar 30 is placed upon bar 10 with holes 28, 32 in 
axial alignment, a screw 34 that carries a washer 36 passes through hole 
32 to hole 28 for threaded engagement therein. 
The engagement of screw 34 within hole 28 causes bar 30 to bear against the 
top of head 22, thereby maintaining the bottom of head 22 against surface 
24T. Since the bottom of head 22 is maintained against surface 24T, shank 
16 is retained within section 14 when pin 18 is being installed. 
A proximal end 38 of bar 10 is integrally connected to a force transfer bar 
40 with a bottom surface 24B and a bottom surface 41B of bar 40 subtending 
an obtuse angle, A (FIG. 3). Bars 10, 40 have substantially the same width 
and thickness. 
A distal end 42 of bar 40 is integrally connected to a lever bar 46, with a 
top surface 41T of bar 40 and a surface 43 of bar 46 subtending an obtuse 
angle, B. Bars 40, 46 have substantially the same width and thickness. 
Applicants have found that angle A is preferably less than angle B. 
A cylindrical member 44 has one end welded to surface 43, with the axis of 
member 44 perpendicular to surface 43. Additionally, a wedge shaped 
support plate 48 is welded to member 44, and surfaces 41T, 43. Similarly, 
a wedge shaped support plate 52 is welded to member 44 and surface 43. 
Support plates 48, 52 provide support for maintaining a fixed connection 
of member 44 to surface 43. 
The other end of member 44 is integrally connected to an anvil 54 that has 
the general shape of a golf tee. More particularly, a flared end 56 of 
anvil 54 is coaxially connected to member 44. An end 58 of anvil 54 is of 
a diameter that makes it adapted for insertion into a percussion sleeve 60 
(FIG. 3) of an air hammer 62. When pin 18 is being installed,member 44 and 
anvil 54 extend upward (FIGS. 1 and 3). 
As shown in FIG. 4, a hinge 64 is connected to a door 66 and to a door jamb 
68 of an automobile. A dashboard 72 of the automobile is adjacent door 
jamb 68. According to the present invention, the displacement of anvil 54 
from slot 12 causes anvil 54 to be at a location where air hammer 62 can 
be conveniently used to either install pin 18 in hinge 64 or extract it 
therefrom. When end 58 is within percussion sleeve 60 with bar 30 bearing 
against the top of head 22 (FIG. 3), force provided by air hammer 62 is 
transferred via anvil 54 and member 44 through bars 42, 40, 30 in the 
direction of arrow 22I to the top of head 22, whereby pin 18 is installed. 
Bar 42 has a threaded hole 70 therethrough. Hole 70 is similar to hole 28. 
When pin 18 is not being installed, bar 30 is placed upon surface 43 with 
holes 32, 70 in axial alignment. Screw 34, with washer 36 carried thereon, 
passes through hole 32 to hole 70 for threaded engagement therein whereby 
bar 30, screw 34 and washer 36 are stored for use when a pin is being 
installed. 
As shown in FIG. 5, when pin 18 is being extracted, member 44 and anvil 54 
extend downward. Additionally, bar 10 is positioned with shank 16 in the 
abutting relationship with end 20 as described in connection with the 
installation of pin 18. When end 58 is within percussion sleeve 60, force 
provided by air hammer 62 is transferred via anvil 54, member 44 and bar 
40 through bars 46, 49, 10 in the direction of an arrow 22E to the bottom 
of head 22, whereby pin 18 is extracted. 
It should be understood that during either the installation or extraction, 
it may be desirable to manually support a distal end 72 of bar 42. Using 
well known principles of physics, it is preferable to have the ratio of 
the distance between end 72 and member 44 and the distance between member 
44 and slot 12 as large as practical, thereby minimizing the manual 
support. 
While the invention has been shown and described with reference to a 
preferred embodiment thereof, it should be understood by those skilled in 
the art that changes in form and detail may be made therein without 
departing from the spirit and scope of the invention.