Pneumatic tools

The tool housing-air motor assembly includes an air motor that is of modular design, that is, it is constructed so that the motor rotor is journaled in the cylinder by the end plates, which retain the motor in its operational alignment condition. The tool housing is used in the "as cast" condition without the necessity for performing any machining operations thereon. The assembly of the air motor and tool housing is possible since the motor is self-contained and does not rely on the tool housing for retaining the parts of the motor in assembled relationship or for retaining the motor parts in operational alignment.

BACKGROUND OF THE INVENTION 
This invention relates generally to improved air tools. More particularly, 
but not by way of limitation, this invention relates to an improved air 
motor and to an improved air motor-tool housing assembly for air tools. 
In the past, pneumatic power tools have included an air motor that is 
generally composed of a rotor journaled in a pair of end plates which are 
retained in spaced relation by a cylinder in which the rotor is located. 
These various components of the motor are retained in operational 
alignment by various shoulders and bores that have been formed in the tool 
housing. In accordance with this concept, the tool housings have been 
relatively expensive and the exchange of air motors in the event of an air 
motor failure, has been necessarily performed by a technician skilled in 
the repair of air tools. While this arrangement has proved reasonably 
satisfactory, it requires an inventory of an excess number of tools and, 
frequently, requires that the air tools be returned to the factory for 
service. 
SUMMARY OF THE INVENTION 
Accordingly, it is an object of this invention to provide an improved air 
motor and an improved air tool housing-air motor assembly wherein the air 
motor can be quickly and easily replaced thereby avoiding the necessity 
for highly qualified service personnel, or the necessity of returning the 
air tool to the factory for service. Therefore, the inventory necessary to 
maintain such air tools can be reduced, since it will be necessary to 
maintain only a few spare air motors for insertion into the air tools. 
This invention provides, in one aspect, a modular pneumatic motor that 
comprises an elongated, hollow motor cylinder; a rotor located in the 
cylinder having a shaft portion; and motor ends journaling the rotor in 
the cylinder and engaging the cylinder for holding the cylinder, rotor and 
motor ends in operating relationship. 
This invention provides in another aspect, an improved tool 
housing-pneumatic motor assembly for pneumatically powered tools wherein 
the assembly comprises an elongated, hollow motor cylinder; a motor rotor 
located in the cylinder that includes shaft portions; and first and second 
motor ends. The ends receive the shaft portion for journaling the rotor in 
the cylinder and for holding the cylinder, rotor and ends assembled in 
operating relationship. A hollow, cast tool housing is included for 
receiving the assembled motor cylinder, ends and rotor. The housing is 
used in the as cast condition. A tool housing end member is releasably 
connected to the housing and engages one of the motor ends to retain the 
assembled motor cylinder, ends and rotor in the housing.

DETAILED DESCRIPTION OF THE EMBODIEMNT OF FIG. 1 
Referring to the drawing, and to FIG. 1 in particular, shown therein and 
generally designated by the reference character 10, is a pneumatically 
powered drill that includes a housing 12 and a chuck 14. The housing 12 is 
hollow and includes a handle portion 16 which will be connected to a 
source of air under pressure and a body portion 18 that is hollow an as 
illustrated, receives an air motor that is generally designated by the 
reference character 20. The housing 12 also includes an end member 22 that 
is threadedly connected to the body portion 18. 
As previously mentioned, the housing 12 is hollow, including an interior 
designated by the reference character 24, an inlet passageway 26 
communicating with the interior 24, and an outlet passageway 28 also in 
fluid communication with the interior 24. The inlet passage 26 is provided 
with an inlet valve 30 that is actuated by a trigger 32 that is slidably 
positioned in a trigger bushing 34. The inlet valve 30 is mounted in a 
bushing 32 that is provided so that the drill 10 can be connected to the 
source of pressurized air (not shown). 
It should also be pointed out that the housing 12 is constructed from a 
plastic that is preferably one of the high density synthetic resins, which 
may if desired, be reinforced with fiber glass. 
The housing 12 is precision cast so that reasonable dimensional accuracy is 
maintained thereby eliminating the need for machining the casting. In 
fact, the interior 24, the inlet passageway 26, and outlet passageway 28 
are utilized in the as cast condition. Bushings 32 and 34 are located in 
the mold prior to casting of the housing 12, and thus require no further 
machining. 
Located in the interior 24 of the housing 12 is the air motor 20 which 
consists of a rotor 36 carrying one or more movable vanes or blades 38. 
The rotor 36 includes shaft portions 40 and 42 for journaling the rotor 36 
in the air motor 20 as will be described. The rotor 36 is mounted in a 
hollow motor cylinder 44 that is provided with appropriate air passageways 
46 for the operation of the motor 20. 
Adjacent to the inlet passageway 26, the motor 20 is provided with an end 
member 48 that has a counterbore 50 located in one face thereof that is 
sized to closely receive the motor cylinder 44. The end member 48 is 
provided with a bearing 52 that rotatably supports the end of shaft 
portion 42 of the rotor 36. 
Similarly, a second motor end member 54 is located in the housing 12 
adjacent the opposite end of the motor cylinder 44. The end member 54 is 
provided with a counterbore 56 that is sized to receive the adjacent end 
of the motor cylinder 44. A bearing 58 is located in the end member 54 and 
rotatably supports the shaft portion 40 of the motor 20. Accordingly, the 
rotor 36, cylinder 44 and end members 48 and 54 are all retained in 
operational alignment due to the inter-engagement between the motor 
cylinder, end members and the shaft portions 40 and 42 of the rotor 36. 
The tool housing end member 22 carries within its interior a planet and sun 
type gear reduction 60 that is operably connected with the shaft portion 
40 of the motor 20. An output shaft 62 of the gear reduction 60 is 
supported for rotation in the housing end member 22 by ball bearings 64, 
as is evident, the chuck 14 is connected to the output shaft 62 for 
driving a drill bit or the like (not shown). 
Upon assembly or repair of the pneumatic drill 10, the tool housing end 
member 22 is separated from the housing 18. The motor 20, assembled as 
previously described, is placed in the interior 24 of the housing 12 with 
the shaft portion 40 being oriented toward the open end of the housing 
portion 18. The tool housing end member 22 with its previously mounted 
gear reduction 60, bearing 64 and output shaft 62, is screwed into the 
housing portion 18 completing the assembly. From the foregoing, it can be 
seen that the air motor 20 can be quickly and easily placed in or removed 
for repair from the drill 10. It is not necessary to provide any shims, 
bushings or alignment features within the motor 20 due to the modular 
structure of the air motor 20. 
In operation, the pneumatic drill 10 functions as any other drill, that is, 
the trigger 32 is depressed opening the inlet valve 30 and admitting air 
through the inlet passageway 26 to the air motor 20. The pressurized air, 
upon reaching the air motor 20, causes the rotor 36 to rotate driving the 
gear reduction 60, the output shaft 62 and connected chuck 14 to rotate 
the drill bit. Air exhausted from the motor 20 passes through the outlet 
passageway 28 and is discharged through appropriate silencers, filters, 
etc. to the atmosphere. 
DESCRIPTION OF THE EMBODIMENT OF FIG. 2 
FIG. 2 illustrates a pneumatic grinder 100 that is constructed by the same 
methods utilized in the manufacture of the pneumatic drill 10. The grinder 
100 includes a housing 102 that is, like the housing 12, constructed 
preferably by casting from one of the high density synthetic resins. If 
desired, the resin can be reinforced with a fiber glass or other suitable 
material. 
The housing 102 includes a hollow interior 104 and inlet passageway 106 
that is connected with the interior 104 through an inlet valve 108. The 
inlet valve 108 is actuated by a trigger 110 through a plunger 112. 
A tool housing end member 114 is threadedly connected to the housing 102 to 
retain air motor 116 therein. An adjustable, plastic exhaust cover 118 is 
snapped into a groove 120 formed in exterior of the housing 102. The cover 
118 is rotatable so that the exhaust can be conventionally directed as 
desired. 
In order to use the housing 102 in the as cast condition, that is, without 
any machining thereon, trigger bushing 122 is cast into the housing. 
Similarly, inlet bushing 124 is also cast into the housing 102 when it is 
formed. The inlet bushing 124 is arranged to be connected with a source of 
air under pressure (not shown) to operate the air motor 116. 
The air motor 116 includes a rotor 126 having shaft portions 128 and 130. 
The rotor 126 carries a plurality of slidable vanes 132. The rotor 126 is 
rotatably located within an air motor cylinder 134, which is provided with 
inlet and exhaust passageways 136 and 138, respectively. 
The cylinder 136 is provided with counterbores 140 and 142 at each end 
thereof for receiving air motor end members 144 and 146, respectively. The 
end members 144 and 146 each carry a bearing for rotatably supporting the 
shaft portions 128 and 130. The shaft portion 128 serves as the output 
shaft and is connected to the desired form of chuck 148, which will of 
course, be arranged to receive appropriate grinder tool (not shown). 
In operation, the trigger 110 is depressed, actuating the valve 108 to 
admit air from the air passageway 106 into the inlet passageway 136 of the 
air motor 116. Air entering the motor 116 causes the rotor 126 to rotate 
driving the output shaft portion 128 and the chuck 148. Air exiting from 
the air motor 116 passes through the outlet passageways 138 and 
subsequently through the exhaust passageways into the atmosphere. 
From the foregoing detailed description, it will be apparent that both 
embodiments of air tool described herein provide a means of using a tool 
housing in an as cast condition. In each embodiment, the air motors 20 and 
116 are modular in configuration, and each is arranged so that the 
components thereof are retained in operational alignment by the inter 
action of the various parts. Thus, it is not necessary to provide precise 
supporting diameter shoulders, etc. within the air tool housing, and thus, 
the tool housings can be utilized in their as cast condition. 
Further, it should be apparent that each of these tools can be readily 
assembled and maintained by relatively unskilled personnel by simply 
inserting the modular air motors therein and placing the housing end 
members thereon to retain the motor in the housing. Substantial reductions 
in inventory can be accomplished, since it is not necessary to stock an 
entire air tool, but only to maintain a small supply of extra motors on 
hand to replace the motors in the event of motor failure in the air tool. 
Obviously, the motors can be quick and easily replaced by unskilled 
personnel to place the air tools back in operating condition. This feature 
eliminates the necessity for returning an entire tool to the factory and 
eliminates the necessity of having highly skilled technicians to repair 
the tools. 
The foregoing examples are presented by way of example only, and it will be 
understood that many changes and modifications can be made therein without 
departing from the spirit and scope of the invention.