Патент USA US2128742код для вставки
2,128,742 Patented Aug. 30, 1938 UNITED STATES PATENT OFFMIE 2,128,742 MUFFLING DEVICE George H. Fuehrer, Phillipsburg, N. J., assigncr to Ingersoll-Rand Company, Jersey City, N. J., a corporation of New Jersey Application April 9, 1937, Serial No. 135,831 4 Claims. (Cl. 121-1) This invention relates to muf?ing devices, and 3i and that portion of the cylinder de?ning more particularly to a mu?iing device adapted the piston chamber 25. The rearriost end 33 to receive the exhaust fluid from a. pneumatic of the sleeve 32 seats against a shoulder at of tool of the percussive type. the back head it and is centralized with respect One object of the invention is to suppress the to the back head by a projection of the back 5 noise induced by the exhaust ?uid issuing from head extending into the sleeve. Thefront end the pneumatic tool. 36 of the sleeve encircles the boss 31 on the Another object is to effectively shield the pneu front head and abuts a shoulder s52, also on the matic tool against the chilling effects of the front head. expanded fluid flowing through the muiiiing de The sleeve is of larger diameter than the 10 vice, and still another object is to equip the cylinder and cooperates therewith to de?ne pneumatic tool with a simpli?ed and e?ective mmiling device of light weight and which may be readily and cheaply replaced. Other objects will be in part obvious and in part pointed out hereinafter. In the drawing accompanying this speci?ca tion and in which similar reference numerals refer to similar parts, 20 Figure 1 is an elevation, in section, of a mu?iing device constructed in accordance with the prac tice of the invention and showing it applied to a pneumatic tool of the percussive type, the tool being partly broken away, and Figures 2 and 3 are transverse views taken through Figure 1 on the lines 2-2 and 3-3, respectively. Referring more particularly to the drawing, the mufl‘ling device, designated in general by 2D, 30 is shown applied to a ?uid actuated percussive tool it comprising a cylinder 22 and front and back heads 23 and 24, respectively. The interior of the cylinder constitutes a pis ton chamber 25 containing a hammer piston 26 35 which actuates a working implement 21 extend ing into the front head and controls the free exhaust port 23 for the piston chamber 25. The piston is of the differential type and has a stem 29 which extends slidably through a bushing 30 40 in the front end of the piston chamber to strike against the working implement 21. The pressure fluid employed for actuating the piston 26 may be distributed to the ends of the piston chamber 25 by suitable valve mechanism 45 of which only the outer casing part 3| is shown. The valve mechanism may, as illustrated, be arranged between the piston chamber and the back head 24 and be in communication with the ends of the piston chamber through the usual ports and passages (not shown). The muf?er constructed in accordance with an expansion space or chamber is to receive the exhaust fluid issuing from the port 263. At the ends of the expansion chamber are trans‘ verse ring plates M5 and [it which may be suit ably secured to the inner surface of the sleeve 32. The plate Ml, which forms the upper bound ing surface of the chamber is disposed inter mediate the exhaust port 23 and the valve mecha_ nism 32 to protect the valve mechanism against 20 exposure to the expanded ?uid flowing through the chamber The plate 40 serves a similar function with respect to the parts lying imme diately forwardly of the front end of the piston chamber 25. 25 In order that maximum suppression of the sound waves be obtained in the expansion chamber 3b a. series of baflles 552, Q3, and d5 are arranged therein in staggered relationship with respect to each other and to extend longi 30 tudinally of the chamber 3?}. The may be said to be arranged in groups on opposite sides of the exhaust port Those designated 42 and "133 constitute one group of which the baf?e t2 extends from the uppermost portion of the chamber St to a point near the partition M, thus leaving a space [it between the baffle and the partition through which ?uid may flow into the space between the battles 42 and 43. The ba?‘le 43, on the other hand, abuts the partition 4| and terminates a su?icient distance below the partition 43 to provide a space M between the ba?le A13 and the partition 41!} for the free passage of ?uid into the portion of the chamber 39 wherein ?nal expansion of the exhaust ?uid takes place before it passes to the atmosphere through outlet openings its in the sleeve and preferably located adjacent the partition M. The other group of battles, consisting of those designated 413 and t5, are arranged in substan— tially the same manner as the baffles 42 and 43, 35 40 45 50 the practice of the invention, is in the form respectively. More speci?cally, the arrangement of a tubular member or sleeve 32 which sur of the ba?ie 44 corresponds with that of the baffle Q2 and the baf?e ‘2-5 is arranged in the manner of the ba?le Q3. Thus, as will be readily 55 rounds the intermediate portion of the pneumatic tool or, more particularly the valve mechanism 2 2,128,742 understood, two tortuous paths are provided for the passage oi the exhaust ?uid from the ex~ haust port 28 to the outlet openings G8. The fluid is thereby required to travel along extended paths and a maximum damping effect is, there fore, obtained. To the end that the portion of the cylinder ly ing in the transverse plane of the expansion chamber 39 may be amply protected against ex 10 posure to the low temperature resulting upon ex‘ pansion of the fluid issuing from the exhaust port 28, the cylinder is encased in a jacket 49 of in sulating material, as for example ?bre. The jacket 49 may ?t the cylinder 22 snugly. Its 15 upper and lower ends are preferably embedded in the back head 24 and the partition 4 I, respec tively. In the periphery of the jacket 49 are 1on~ gitudinally extending grooves 50 which inter lockingly engage the inner edges of the bailles to assure against relative rotation between the sleeve 32 and the jacket 49 and also to maintain ing the sound vibrations caused by the intermit tent impulses of the exhaust ?uid ?owing from the piston chamber. During its passage through the sleeve the exhaust ?uid passes in opposite di rections from the exhaust port 28, thence in zig zag fashion along different paths to the atmos phere. The exhaust impulses are thereby evened out without causing an appreciable back pres sure and the ?uid passes through the outlet open ings 48 to the atmosphere as a substantially con 10 stant stream. I claim: 1. In a mufliing device, the combination of a pneumatic tool casing having a piston chamber and an exhaust port for the piston chamber, a 15 sleeve to surround the casing and cooperating therewith to define an expansion chamber for exhaust ?uid, an outlet opening in the sleeve, and means to prevent contact of the exhaust ?uid in the expansion chamber with the casing. the jacket seated against the cylinder. pneumatic tool casing having a piston chamber In order to prevent buckling or distortion of the jacket 49 as a result of expansive and contractile movements of the metal parts incident to their and an exhaust port for the piston chamber, a exposure to temperatures of widely spaced degree, haust ?uid, an outlet opening in the sleeve, and a rubber ring 5| is disposed in the partition M to act as a seat for the adjacent end of the jacket. The ring 5| may be of such thickness as to cause 30 partial displacement of the rubber when the cas~ ing parts of the rock drill and the muifiing device are clamped together, in assembled relationship. The jacket 49 will thereby, at all times, be held against endwise vibratory movement and conse ‘ quent damage. As is well known under certain climatic condi tions the temperature resulting upon expansion of the exhaust ?uid causes the moisture en- trained by the fluid to congeal and seriously re 40 strict the areas of the passages through which the ?uid ?ows to the atmosphere. In order to pre vent an occurrence of this nature in the immedi~ ate vicinity of the exhaust port 28 a flexible sheet or ?ap 52 of rubber or fabric is arranged within the sleeve to confront the exhaust port 28. sleeve to surround the casing and cooperating therewith to define an expansion chamber for ex a jacket of insulating material encasing the eas expansion chamber with the casing. 3. In a muii'ling device, the combination of a 30 penumatic tool casing having a piston chamber and an exhaust port for the piston chamber, a sleeve to surround the casing and cooperating therewith to de?ne an expansion chamber for; the exhaust ?uid issuing from the piston cham 35 ber, a jacket consisting of insulating material en casing the casing to prevent contact of the ex haust ?uid in the expansion chamber with the surface of the casing, and bail‘les in the sleeve to form a tortuous path for ?uid between the ex haust port and the outlet opening and to support the jacket. 40 4. In a mufiling device, the combination of a pneumatic tool casing having a piston chamber and an exhaust port for the piston chamber, a 45 sleeve to surround the casing and cooperating tion of the sheet 52 may be effected said sheet therewith to de?ne an expansion chamber for is suspended from the partition 40 and spaced with respect to the sleeve 32. Thus, when the ex ill) haust impulses strike the sheet it will be ?exed the exhaust ?uid issuing from the piston cham ber, an outlet opening in the sleeve, a jacket of material of low heat conductivity to insulate the casing, and baffles in the sleeve arranged in stag broken up and be carried to the atmosphere by the stream of exhaust ?uid. In practice, the present invention has been gered relationship between the exhaust port and the outlet opening and engaging the jacket to hold said jacket against the casing. 1 found to be a highly e?icient device for suppress 25 ing to prevent contact of the exhaust ?uid in the To the end that an undulatory or flapping mo and any ice which may form on the sheet will be 20 2. In a mu?iing device, the combination of a GEORGE H. FUEHRER.