US2955573A

US2955573A - Pneumatic tool

Info

Publication number: US2955573A
Application number: US713694A
Authority: US
Inventors: Jacob E Feucht
Original assignee: Westinghouse Air Brake Co
Current assignee: Westinghouse Air Brake Co
Priority date: 1958-02-06
Filing date: 1958-02-06
Publication date: 1960-10-11
Anticipated expiration: 1977-10-11

Description

J. E. FEUCHT PNEUMATIC TOOL Oct. l1, 1960 Filed Feb. 6, 1958 mlm.

Il'lllillaV "nulli III 'lll/11,111

United States Patent PNEUMATIC TOOL Jacob E. Feucht, Garfield Westinghouse Air Brake a corporation of Pennsylvania Filed Feb. 6, 195s, serpgNo. 113,694 s claims. (ci. 121-32) Heights, Ohio, assignor to This invention relatesV generally to pneumatic tools, such -as clay spades fand the like, in which compressed air is fed Vinto a cylinder in the machine housing to reciprocate a hammer. The hammer in turn strikes a tool which extends from the end of the machine. The air is then ported to the atmosphere.

Conventional tools of this general character have cerltain shortcomings, for example, foreign matter enters the chuck or tool end of the machine while the latter is operating to cause malfunctioning. thereof. Another objection to these tools has been the discharge of air which heretofore was blown toward the operator or adjacent workmen, or was blown toward the side of the ditch being formed with a resulting spray of dirt over the area.

In operation these tools are held at their front end by the operator and in certain types of operations the tool a generallycylindrical andelongated housing having Company, Wilmerding, Pa.,

a backhead 11 rigidly secured thereto.- v

Compressed air is supplied to the machine via the connection 12 in the backhead and admission of this air is controlled by the actuating throttle valve 13. The valve in turn is controlled by the throttle lever 1S, pivoted at 16, which shifts the link 17 to move the valve to the open position. A spring 18 urges the valve to the closed position.

Air is ported through passage 19 to chamber 20 in the valve chest 21 where it is diverted to either front chamber 22 via port 23, or to rear chamber 24 via port 2S.

An annular groove or port 27 is formed in the bore 28 which forms

chambers

22 and 24. Additional

concentric bores

30, 31,32 and 33 are formed in series along the length of the housing 10.

becomes very hot and therefore diicult if not impossible to handle. This heat also adversely effects the wear life of certain parts. l

A general object of the present invention is to provide a pneumatic tool which overcomes the above mentioned difficulties.

In accordance with the present invention a pneumatic machine has been provided in which the exhaust air is directed through the front end of the machine where it emerges `at a reduced velocity and-is directed toward the end of the tool. By so exhausting the air, dirt or other foreign matter is prevented from entering the working parts, such as between the tool shank and the chuck, while the machine is operating. Any foreign matter that has entered the machine during an idle period of the tool will be immediately ejected when the machine is started because of the large volume of air exhausted past these parts.

The invention also contemplates the cooling of the front end of the machine by the exhaust air so as to enable the operator to firmly grasp the machine at allV times. This cooling is also effective to prevent overheating of the buffer parts and contributes to increased wear life thereof.

Another aspect of the invention provides a pneumatic machine having a front end construction which permits ready removal and insertion of the tools therein, and which permits the use of a relatively small diameter cylindrical shape, free of any projections, which can be conveniently held by the operator.

Theinvention furthermore provides a novel buier construction and assembly for such a machine which will absorb the shock of the hammer impact on the tool when the tool is not in contact with the work, as when being withdrawn from the lwork.

These and other objects and advantages of the invention Will appear hereinafter as this disclosure progresses, reference being had to the accompanying drawings in which:

Figure 1 is a longitudinal cross-sectional view of a machine made in accordance with the present invention; and

A hammer 35 is reciprocable in bore 30 and has a piston 36 formed integrally therewith which reciprocates within bore 28.

y The piston and hammer are reciprocated in the con-- ventiona-l manner by alternately porting compressed air to the front and

rear chambers

24 and 22 respectively, by

the automatic operating valve 38. The compressed' air that is used to reciprocate the piston is exhausted to at mosphere via annular groove 27 and passageway 40.

A chuck bushing 42 is mounted within bore 32 and the spade shank 43 has a collar 44 which engages the rounded'.

end 45 of the bushing so as to be limited in its retraction. within the housing. The hammer engages the inner end of the shank and' the outer end extends outwardly of the housing and has a spade portion 46 formed thereon.

The bore 33 contains the split stop ring 48 against which the collar 44 strikes when moving in an outward direction. Another ring 49 is 4also secured in the bore and a resilient tubular-shaped buier 50 is held captive in the bore between the

rings

48 and 49.

f The

rings

48, 49 and the buffer are held in assembled relationship by the garter spring 51l which is snapped into its retainer groove 52.

The garter spring consists of a closely wound steel spring having coils with little space therebetween. The ends of the spring are joined to form a continuous ring which makes assembly and disassembly convenient, but a continuous ring is not essential.

When the spring is snapped into the groove 52, about one-half. of its coils are exposed for holding ring 49. This provides a substantially complete circumferential bearing surface for positive retaining action against ring 49. The ring 49 not only provides a solid backing for the buffer 50 but also provides a good surface for action by the retaining spring.

The buffer serves to absorb the shock of the impact that occurs when the spade is struck by the hammer but is not in contact with the work. Such a situation occurs when the tool is being Withdrawn from the work.

The spring snap ring, split ring and buffer assembly permits removal of these parts without the necessity for special tools. It is only necessary to insert a nail, screwdriver or other pointed object in either slot 53 behind the ring 51 in order to remove it.

The outside configuration of the end of the housing can be made relatively small and of smooth cylindrical shape which affords a surface that is easy to grip and hold for long periods of time.

The exhaust passageway 40 is in communication with past the buffer 50. This exhaust air not only prevents the ports from being overheated but also keeps foreign matter from accumulating in the housing. The air passes through areas of progressively larges cross section as it passes through to discharge and by the time it emerges from the machine, its velocity has been reduced considerably.

Another cross port 55 connects passage 40 with bore 31. Oil carried by the air will thereby reach the chuck 42 and its adjacent associated parts and thereby lubricate the same which facilitates the changing of the tools.

Various modes of carrying out the invention are contemplated as being within the scope of the following claims particularly pointing out and distinctly claiming theV subject matter which is regarded as the invention.

I claim:

1. In la pneumatic machine having an axial bore therein and opening out one end thereof, a tool reciprocable in said bore within limits and extending freely through said bore and outwardly from said machine, an exhaust passageway extending substantially parallel to and laterally of said bore, said passageway being in air exhausting communication with said axial bore whereby exhaust -air passes between said tool and said bore for blowing foreign matter generally axially from said machine, the air flow capacity of the space between the bore and the tool being greater than that of said passageway.

2. In a pneumatic machine having an axial bore therein and opening out one end thereof, a resilient buier confined Within said bore, means providing positive bearing stops at opposite ends of said buffer and preventing longitudinal displacement thereof, while permitting compression between said limit stops, a tool reciprocable in said bore and extending freely through said buffer and outwardly from said machine, an exhaust passageway in air exhausting communication with said axial bore whereby exhausted air is directed between said tool and said buffer for blowing foreign matter axially from said ma\ chine and for cooling said buifer.

3. In a pneumatic machine having an axial bore there in and opening out one end thereof, a pair of steel rings mounted in said bore, a tubular-shaped resilient buffer in said bore and between said rings, a retaining ring mount ed in said bore for holding said rings and buffer captive in said bore, a tool reciprocable in said bore and extending freely through said buffer and outwardly from said machine, an exhaust passageway in air exhausting communication with said axial bore above said buffer whereby exhausted air is directed between said tool and said buffer for blowing foreign matter axially from said machine and for cooling said buffer.

4, In a pneumatic machine having a hammer reciprocable lin a housing by alternately porting compressed air to chambers on opposite sides of said hammer, said housing having an axial bore therein and opening out one end thereof, a resilient buffer securely mounted in said i' bore and retained against axial displacement therein, a

reciprocable tool engageable by said hammer and extending freely through said buffer and outwardly from said housing, an exhaust passageway extending longitudinally of the housing outwardly `of said bore and placing said chambers in air exhausting communication with said axial bore above said buffer whereby air exhausted from said chambers passes between said tool and said buffer for blowing foreign matter axially from said housing and cooling said buffer.

5. In a pneumatic machine having 'a hammer reciprocable in a housing by alternately porting compressed air to chambers on opposite sides of said hammer, said housing having an axial bore therein and opening out one end thereof, a pair of steel rings mounted in said bore, a tubular-shaped resilient buffer in said bore and between said rings, a retaining ring mounted in said bore for holding said rings and buffer captive in said bore, a reciprocable tool engageable by said hammer and extending freely through said buffer and. outwardly from said housing, an exhaust passageway placing said chambers in air exhausting communication with said axial bore above said buffer whereby air exhausted from said chambers passes between said tool and said buffer for blowing foreign matter axially from said housing and cooling said buffer.

References Cited in the file of this patent UNITED STATES PATENTS 1,391,629 Haight Sept. 20, 1921 1,481,643 Jimerson Ian. 22, 1924 1,787,178 Stevens Dec. 30, 1930 1,846,804 Hansen s Feb. 23, 1932 2,219,816 Mould Oct. 29, 1940 2,337,351 Schorer Dec. 12, 1943 2,500,669 Docg Mar. 14, 1950 2,554,568 IGillerstrorn May 29, 1951 2,672,129 Fischer Mar. 16, 1954 2,738,769 Holman et al. Mar. 20, 1956 kan...