US2737774A

US2737774A - Shield for engine mufflers associated with sawing machines

Info

Publication number: US2737774A
Application number: US338183A
Authority: US
Inventors: Sidney S Stiers
Original assignee: Individual
Current assignee: Individual
Priority date: 1953-02-24
Filing date: 1953-02-24
Publication date: 1956-03-13
Anticipated expiration: 1973-03-13

Description

March 13, 1956 s. s. STIERS SHIELD FOR ENGINE MUFFLERS ASSOCIATED WITH SAWING MACHINES 2 Sheets-Sheet 1 Filed Feb. 24, 1955 FIG].

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INVENTOR Sidneyfi. Stiers 2 ATTORNEKZ March 13, 1956 s. s. STIERS SHIELD FOR ENGINE MUFFLERS ASSOCIATED WITH SAWING MACHINES 2 Sheets-Sheet 2 Filed Feb. 24, 1953 INVENTOR 5i (1')?5/5- .S' tiers ATTORNEY;

United States Patent SHIELD FOR ENGINE MUFFLERS ASSOCIATED WITH SAWIN G MACHINES Sidney S. Stiers, Lowell, Greg. Application February 24, 1953, Serial No. 338,183 1 Claim. (Cl. 60-31) The present invention relates to a muflller attachment for use with engines and, more particularly, to a shield or guard arranged to be associated with the muflier of an internal combustion engine or the like.

Heretofore, gas motor chain power saws for cutting timber such as trees and logs, have created a serious fire hazard and have been responsible for a large number of forest fires, due to the fact that the mufilers on such motor saws soon become overheated with the result that any inflammable material, such as sawdust and the like that comes in contact with the mufller are quickly ignited.

Accordingly, an important object of the present invention consists in providing simple, eflicient and inexpensive means in the form of a shield having a tubular portion enclosing the muffler and spaced therefrom to provide a cold air circulating passage that extends completely around the mulfier. Additionally, the inner end of the tubular portion of the shield is preferably formed on one side with a radially and outwardly extending flange that constitutes an air scoop. The opposite side of the tubular member adjacent the inner end thereof is provided with a transversely disposed air slot which coacts with the air scoop to introduce cold air into the passage between the mufller and the shield, so as to cause the temperature of the exhaust gases passing through the muflier to be cooled to such an extent that any inflamrnable object, such as sawdust and the like, which may accidentally come in contact with the shield, will not catch fire. Thus, it will be seen that means which can be quickly and easily installed are provided for reducing the intense heat of the exhaust gases as they are discharged from the mufller so as to reduce the danger of forest fires and the like, previously caused by the use of motor-driven power saws of this type.

Another object consists in associating with the shield and the flywheel of an air cooled motor, means for con ducting a portion of the air used to cool the motor through the shield, and mixing this air with outside air prior to its passage through the shield in order to assist in reducing the heat transferred to the shield by the exhaust gases passing through the muffier.

Other objects and advantages of the invention will become apparent from the following description when taken in conjunction with the accompanying claim and drawings.

Referring to the drawings, in which is disclosed for illustrative purposes, one form the invention may assume,

Figure 1 is an elevational view of a stationary motor provided with a muffler shield constructed in accordance with the present invention, and shown operatively associated with an endless chain sawing machine.

Figure 2 is a plan View of the sawing machine assembly shown in Figure 1.

Figure 3 is a detailed side view showing the shield enclosing the muflier and attached thereto, and with parts in section for clearness of illustration.

Figure 4 is a right-hand end view of Figure 3 with the muffler removed.

Figure 5 is a bottom plan view of Figure 3.

Figure 6 is a left-hand end view of Figure 5, and

Figure 7 is a plan view of Figure 3.

Referring to the drawings, 10 indicates a stationary motor which is shown associated with a sawing ma chine 11, of any well-known type. The engine 10 is enclosed in a casing 12 (Figure 2) and may have an offset inner portion 13 in which is rotatably mounted the flywheel 14 that is operatively connected to the drive shaft of the engine, not shown. The outer end 15 of the portion 13 of the casing 12 is preferably provided with a reticulated screen or opening 16 for introducing cold air into the casing in order to provide means for cooling the engine or motor during the operation of the machine. The sawing machine 11 is provided with the usual endless chain 17 which carries the cutting teeth 18 and may be operatively connected to the drive shaft of the engine in the usual well known manner. The front 19 of the casing 12 on one side of the sawing machine 11 has an outwardly flared wall 20 terminating in a substantially elliptical-shaped end plate 21 provided with horizonttlly spaced exhaust openings 22 (Fig. 5). An elliptical-shaped muffler 23 has at its inner end a plate 24 similar in shape to the plate 21 and is provided with spaced openings 34 which register with the exhaust openings 22. The muffler is firmly secured to the engine 20 by the retaining bolts 25 which extend through aligned openings 25' (Fig. 4) in the

end plates

21 and 24 respectively when the parts are assembled. Manifestly, the shape of the mufller and the end plates may be of any suitable circular or non-circular configuration as the particular operating conditions may require.

Due to the intense heat of the exhaust gases, as they discharge from the muffler, it will be seen that any inflammable material which might accidentally contact or collect on the mufller during the operation of the machine, would soon ignite and cause a serious fire hazard, particularly where the motor is used for sawing timber in the forest, such as the trunks of trees, logs, and the like. Accordingly, a guard attachment in the form of a shield 26, made of any suitable durable metal or the like, is associated with the muffler 23. The shield 26 preferably includes an elongated tubular portion or sleeve 27 opened at both of its ends and having the major portion thereof of substantially the same configuration as the mufller. The inner or rear end 28 of the tubular member 27 has laterally and outwardly extending therefrom a flange 29 that projects from one side thereof and which is preferably curved and shaped as shown in Figure 5, so as to extend substantially halfway around the elliptical tubular portion 27 in order to constitute an air scoop for conducting cold air into the shield 26. The inner end 28 of the shield opposite the air scoop 29 has a transversely disposed slot 30 (Fig. 7) that provides additional means for introducing air into the tubular portion 27 so as to insure complete circulation of the cooling medium through the shield.

The shield 26 is connected to the mufiler 23 at only two spaced points 31 (Fig. 7) in any suitable manner, such as by welding or the like 32, so as not to otherwise interfere with the introduction of cold air into the tubu lar portion 27 of the shield through the scoop 29 and the slot 38. The tubular portion 27 of the shield is larger than the muffler 23 so as to provide a space or passage 33 completely around the mufller for conducting air from the inner end to the outer end of the shield when the parts are assembled.

The outer end portion 35 of the mufller 23 is laterally offset and extends outwardly and away from the sawing Mama.

machine 11, so as to conduct the exhaust gases away from the tree or log being cut. The end portion 35 may also be provided with a substantially elliptical plate 36 having transversely disposed louver openings 37 for deflecting the exhaust gases outwardly and away from the sawing machine. The shield 26 'is also shaped or bent to provide an angulated outer end portion 38 simi 'lar in shape to the end portion 35 and spaced therefrom to form a continuation of the air passage 33 so that the shield is opened throughout the length thereof for re- 2 tend beyond the offset reduced side portion 10' of the casing 10 (Fig. 2) to a point adjacent but spaced from the air scoop 29 so that the cold air forced into the casing 10 has a portion thereof deflected so as to pass through the grooves 4%, where a portion of this air discharges to the atmosphere. The remaining portion of the air discharges into the scoop 29 and draws with it outside air which, as it circulates through the passage 33, coacts with the outside air introduced into the passage 33 through the slot 3 to flow completely around the mufiler 23 thus causing the temperature of the exhaust gas passing through the mufiier to be cooled to such an extent that any inflammable object, such as sawdust or the like, that might collect onthe shield, will not catch fire. Further, the shield or guard provides means that may be quickly installed on any type of rnuifier for the purpose of greatly reducing the temperature of the exhaust gases as they are discharged into the atmosphere.

The stationary engine 10 may be supported by any suitable means such as the frame assembly 41, in which the engine 10 and its associated parts are mounted, so as to be readily transported from place to place at a minimum expenditure of time, effort and cost. The stationary air cooled motor I'll may be formed of one or more gas cylinders and while shown operatively connected to an endless chain power saw, it will be manifest that it may be used with equal efficiency with various other types of engines. The shield 26 is preferably co-extensive in length with the muffler 23 and forms therewith the continuous or uninterrupted air passage 33 that completely encloses the muffier so that the cold air passing through the shield contacts a wide area of the muflier to reduce the heat of the exhaust gases passing therethrough.

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Thus it will be seen that an air cooled shield attachment is provided for the muffiers of internal combustion engines that can be easily installed and is readily accessible for inspection or repair. Further, the tubular shield constitutes eflicient means for preventing the ignition of inflammable material such as s wdust and the like, which might accidentally contact or collect thereon. By reason of the novel association of the shield with the muffler and the engine, a constant flow of cold air is insured to be conducted between the mufiler and the shield so as to maintain the latter at a desired low temperature.

It will be understood that the form of the invention shown is merely illustrative of a preferred embodiment and that such changes may be made as come within the purview of the following claim.

i claim:

In combination with an air-cooled internal combustion engine having a casing provided on one side with vertically spaced fins for forming longitudinal air passages, means for circulating air through said passages, a muffler communicating with the casing on one side thereof for discharging exhaust gases from the engine, a shield having a tubular portion encircling the muffler and spaced therefrom to form an air circulating passage, said tubular portion having an opened inner end provided with a laterally and outwardly projecting flange spaced from the casing and constituting an air scoop positioned in front of and adjacent said fins for receiving air as it issues therefrom, said shield adjacent its inner end and on the side opposite said air scoop having a slot for introducing outside air into said tubular portion, said muffler having an angularly disposed outer end closed'by a plate provided with transversely spaced louver openings, said tubular portion having an outer end bent to encircle the outer end of the mutiler and be spaced therefrom to form a continuation of the air circulating'passage, and means con necting said shield to the casing so as not to interfere with the passage of the air from the casing into the mufiler, the parts being constructed and arranged so that any inflammable object coming in contact with the shield is not ignited by the heat of the muflier.

References (Iited in the file of this patent UNITED STATES PATENTS 867,271 Hofmann Oct. 1, 1907 917,081 Krygowski Apr. 6, 1909 1,132,391 Ruttle Mar. 16, 1915 1,634,000 Smith June 28, 1927 2,138,001 Fluor, Jr Nov. 29, 1938 2,382,387 Alford Aug. 14, 1945 2,519,936 Sayre Aug. 22, 1950