US3379278A

US3379278A - Muffler for pneumatically powered tools

Info

Publication number: US3379278A
Application number: US610263A
Authority: US
Inventors: Skowron Carl
Original assignee: Individual
Current assignee: Individual
Priority date: 1967-01-19
Filing date: 1967-01-19
Publication date: 1968-04-23
Anticipated expiration: 1985-04-23

Description

April 23, 1968 c. SKQWRON 3,379,278

MUFFLER FOR PNEUMATICALLY POWERED TOOLS Filed Jan. 19, 1967 INVENTOR. CARL SKOWRON ATTORNEY United States Patent 3,379,278 MUFFLER FOR PNEUMATIQALLY POWERED TOOLS Carl Sltowron, M. C. #1, Damascus Road, Salem, Uhio 4446i) Filed Jan. 19, 1967, Ser. No. 610,263 4 Claims. (Cl. 181-36) ABSTRACT OF THE DISCLOSURE This disclosure relates to a sound deadening device for use on a pneumatic tool such as a grinder. An open-ended sleeve of an elastic, resilient material is tightly fitted over the body portion and exhaust ports of the tool, being bonded to the body portion. Spent air exhausted from the tool forces the sleeve away from the tool and escapes at the end of the sleeve. A band of non-elastic material is placed around the body of the tool closely adjacent the exhaust ports in the opposite direction from the end of the sleeve through which the air escapes. This band is secured to the sleeve and prevents air from forcing the sleeve away from the body portion of the tool.

Pneumatic grinders used in many industrial operations are supplied with compressed air at approximately 120 p.s.i. through conduits from a compressor. The air is discharged from the grinder through ports in the body of the tool and the escaping air generates a high pitched whine which may reach a level in excess of 160 decibels. Noises at this level are sufficient to cause damage to the human ear and may cause deafness. If several pneumatic tools are operated in the same enclosed area, the resulting noise produces unpleasant working conditions and impairs the efficiency of those working in the area. The compressed air used to power these tools may carry oil mist from the compressor and the tool and, especially in humid conditions, large quantities of water vapor. These vapors and mists are discharged along with the spent air and are frequently sprayed on the tool operator. When the compressed air expands upon discharge from the tool it absorbs heat from the body of the tool and, thus, the tool is unpleasantly cold to the touch. Previously proposed mulilers designed to overcome these problems have been of complex construction and their use makes the tool awkward to handle and operate.

It is the primary object of my invention to provide a noise muiiling device for use on a pneumatically powered tool which dampens the noise generated by the discharging of spent air from the tool. Another object of the invention is the provision of such a device which directs the spent air away from the operator protecting him from the vapors and mists carried by the air. A further object of the invention is the provision of a noise muflling device which provides a comfortable gripping surface for the operator. It is also an object of the invention to provide such a device which is of simple construction, is easily installed, and which may be used with existing pneumatic equipment without the necessity of altering such equipment.

The above and other objects and advantages of the invention will become apparent upon consideration of the following specification and the accompanying drawing wherein are shown preferred embodiments of the invention.

In the drawing:

FIGURE 1 is a side elevational view, partially in section, of a pneumatic grinder equipped with the device of my invention;

FIGURES 2 and 3 are views similar to FIGURE 1 but showing modified forms of the muffler of the invention; and

FIGURE 4 is an end view of the tool and muffler of FIGURE 3.

The air operated grinder to which the silencing device of the invention is applied has a cylindrical body portion 11 which houses the air-driven rotor. A grinding stone or wheel 12 is mounted on shaft 13 which is an extension of the shaft of the rotor. Compressed air is admitted to the tool through fitting 14, controlled by valve 15, passes the rotor and exhausts through ports 16 of collector ring 17. It is this exhausting of the spent air through ports 16 that produces the offensive, undesirable noise. To reduce the level of noise produced and to direct the escaping air away from the operator, I provide a tubular sleeve 18 of resilient, elastic material having reenforcing

end ribs

19 and 20 which tightly fits about the body portion 11 of the tool and extends beyond the collector ring 17, being tightly fitted to both the body portion 11 and the collector ring 17 as well as the end portion 21 of the tool. The air exhausted through ports 16 forces the portion of sleeve 18 from the collector ring 17 to the end of the tool body 21 outwardly and escapes at the end of the sleeve 18. The resiliency of sleeve 18 absorbs a por tion of the noise produced by the escaping air and, thus, reduces the level of noise produced. In order to firmly secure the sleeve 13, that portion which surrounds the body portion 11 of the tool is bonded thereto and a band 22 of non-elastic material is placed tightly around the portion of the sleeve covering the body portion 11 closely adjacent the collector ring 1"]. The band 22 prevents the bonded joint between sleeve 18 and body portion 11 from being forced apart by compressed air backing up from the exhaust ports 16. It will also be apparent that the spent air is now discharged toward the grinding wheel 12 rather than toward the operator thus protecting him from the water vapors and oil mists which may be carried by the air. As the resilient, elastic rubber or synthetic polymer material of which sleeve 18 is made is inherently insulating, the portion of the sleeve secured to the body portion 11 of the tool provides a gripping surface for the operators hand which does not become cold to the touch even when the body 11 is cooled by the escaping air.

In the modification shown in FIGURE 2, a strip of resilient material 23 is spirally wound about a portion of the body 11, the collector ring 17, and the end portion 21, the overlapped portions of strip 23 being bonded together. A tubular sleeve 24, similar to sleeve 18, fits over the end of band 23 and is bonded to the cylindrical body 11 of the tool. The strip may be wound with successively less tension toward the end portion 21 providing a low resistance path for the escaping air. In this embodiment only that portion of the mufiling device which becomes worn or damaged need be replaced. If, for example, the strip 23 becomes worn, it may be replaced by a new wrapping while sleeve 24 is reused.

When it is desirable to reduce the back pressure of the exhausted air while yet mufiling the noise and directing the discharge of spent air away from the operator, the embodiment of the invention shown in FIGURES 3 and 4 may be used. A sleeve 25 is fitted over and bonded to body portion 11 and is provided with a restraining band 26 similar to band 22. The portion 27 of sleeve 25 overlying collector ring 17 is spaced therefrom providing an annular chamber 28 into which the spent air is exhausted. Extending longitudinally from sleeve portion 27 is a double-walled portion 29, the inner wall 39 of which tightly surrounds end portion 21 of the tool and the outer wall 31 of which is spaced from inner wall 30 providing an annular passage 32 open to chamber 28. The ends of walls 39 and 31 are joined by a ring-like member 33 having a plurality of holes 34. Air discharged into chamber 28 moves through passage 32 and exhausts through holes 34-.

it will now be apparent that I have invented a muffler for pneumatic tool-s which is characterized by its simplicity and which is capable of substantially reducing the level of noise produced by the discharge of spent air from the tool. In addition the device herein described provides a comfortable gripping surface for the operator and pro tects him from the discharged air.

It should also be apparent that changes may be made in and to the device of my invention without departing from the spirit thereof. For example, the restraining band 22 may be secured to the inner rather than the outer surface of sleeve 18. It is also conceivable that, rather than using a tubular sleeve, the mufiier could be formed of a length of resilient, elastic material tightly wrapped about the tool, bonded to body portion 11 and the overlapped portion of the wrapping bonded together. This method of fabricating the muffler has the advantage of being readily adaptable to pneumatic tools of different sizes. For an understanding of the true scope of my invention reference should be had to the accompanying claims.

Having described my invention what I claim is:

1. A cover providing a gripping surface and rnuflier for a pneumatically powered tool having a generally cylindrical body portion housing an air-driven rot-or, a connection to a source of compressed air at one end of said body portion, a second cylindrical portion of lesser diameter than said body portion extending therefrom at the opposite end from said connection and having ports for discharging spent air from said tool, a third cylindrical portion extending from said second cylindrical portion, and an output shaft driven by said rotor and journaled in said third portion, comprising: an open-ended tubular sleeve of resilient material encompassing said body portion and said second and third portions of said tool and bonded to said tool along the portion of said sleeve extending from the end of said sleeve adjacent said connection to a compressed air source to said exhaust ports, the remaining portion of said sleeve being in close fitting engagement with the adjacent portions of said tool but not bonded thereto; the arrangement being such that spent air discharged from said ports passes between said sleeve and said second and third portions of said tool and is discharged to the atmosphere at the end of said sleeve adjacent the outer end of said third portion of said tool While that part of said sleeve overlying said body portion remains in tight fitting relation thereto.

2. A device according to claim 1 further including a band of non-elastic material surrounding said body portion of said tool closely adjacent said second portion of said tool and rigidly bonded to said sleeve.

3. A cover according to claim 1 further characterized in that said sleeve is comprised of a strip of resilient material wound in spiral, overlapped relationship about a part of said body portion and about said second and third portions, the overlapped portions of said strip being bonded together and the portion of said strip wrapped about said body portion being bonded thereto; and a resilient tubular sleeve surrounding said body portion and the portion of said strip wrapped about said body portion of said tool and bonded to said body portion and to said last-mentioned portion of said strip.

4. A cover according to claim 1 further characterized in that said sleeve is comprised of a length of tubing of resilient material bonded to the body portion of said tool and extending in spaced relationship about said second and third portions of said tool; a second length of tubing of resilient material fitting tightly about said third portion of said tool; and a ring-like member connecting the ends of said tubing lengths and having a plurality of holes communicating with the annular space between said tubular lengths; the arrangement being such that air exhausted through said ports flows through the annular chamber between said first length of tubing and said second portion of said tool, then through said annular space "between said tubular lengths and is discharged through said holes in said ring-like member.

References Cited UNITED STATES PATENTS 1,115,704- I l/1914 Manes 181-36 2,789,652 4/1957 Fannen 181-36 2,949,975 8/1960 Plummer 181-36 3,202,239 8/1965 Clarke 181-36 3,225,861 12/1965 Reynolds 181-36 FOREIGN PATENTS 496,454 '1 1 1938 Great Britain.- 1,805 3/1964 Great Britain.

ROBERT S. WARD, JR., Primary Examiner.-