US1593615A - Cooling device for pneumatic tools - Google Patents

Description

w. F. ZIMMERMANN COQLING DEVICE FOR PNEUMATIC TOOLS Filed Sept, 6. 1925 N VE N TOR. 117272111112 I! 1121.222 0291101111 #15 AT RNEK.

Patented July 27, 1925.

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WILLIAM FRANK ZIMMERMANN, OF WAVERLY, NEW YOBIZ, ASSIGNOR TO INGEESOLL- RAND COMPANY, OF JERSEY CITY, JERSEY, A CORPORATION OF NEW JERSEY.

COOLING DEVICE FORPNEUMATIC TOOLS.

Application fi led September 16, 1925. Serial No. 56,612.

This invention relates to pneumatic tools, but more particularly to a cooling device for riveting hammers and the like, having a cylinder, a reciprocating piston, which constitutes the hammer, and a fluid actuated distributing valve.

The objects of the invention in particular are to secure means for cooling the forward end of the cylinder or barrel by conducting the whole or a portion of the exhaust fluid through passages in the forward end of the barrel and thence rearwardly to a rearward exhaust port. r i

The cooling of the barrel, and especially the front end of the barrel, is particularly desirable with pneumatic hammers of the shorter lengths which are more frequently used for such service, as car fabrication, in which rivets of standard sizes are driven rapidly in succession so that the heat from the rivet is transmittedthrough the rivet set to the barrel and. thence up the barrel. This transmission ofheat forces the hammer operator to gradually withdraw the hand away from the forward end ofthe bar,- rel, resulting in the disadvantage thatthe riveting hammer is more difiicult to'guide and hold properly while the rivet is being driven. v y I If the exhaustfluid is. discharged through the forward end of the barrel immediately around thevrivet set, any scale loosened duringthe riveting hasa tendency to be blown into the operators face and one of the'objects of this invention is to avoid this disadvantage and yet obtain the desired cooling effects around the shank of the rivet set or other impact nnplement and throughout the barrel. Either the entire exhaust fluid or only a portion of the exhaust fluid, as desired, may be by-passed through the wall of the barrel and thence through a passage around the forward end of the barrel and thence rearwardly to theusual exhaustport. One of the advantages of by-passing only a portion of the exhaust fluid, as indicated, resides in the fact thatsuch by-pass may be more conveniently applied to existingriveting hammers without change in the valve perating mechanism,

The invention hown in one of its prefered formsin the accompanyingdrawings, in which 7 Figure 1 is a longitudinal sectional side view, partly broken away, of a riveting hammer having the invention appliedthereto, and f Figure 2 is a similar view showing the piston and the valve in a different position.

A The type of pneumatichammer selected for illustration of the invention is like that described in U. S. Patent No. 1,528,781, grantechlt-larch 10., 1925 to Gaid H. Peck and is in all respects like the said pneumatic hammer including the same distributing valve, but halvingthe present cooling means incorporated in the pneumatic hammer.

'Referring to the drawings of the present application, the pneumatic hammer comprises the cylinder A having a bore B in which the hammer piston C is adapted to reciprocate and impart blows of impact to a rivet set D or other tool removably held within a forward. end of the cylinder as by means of the rivet set clip E of any suitable character. A suitable handle F secured to the cylinder as by means of the bolts G forms the back head of the machine and pressure fluid from the inlet H controlled by a hand operated valve (not shown) 0011- so nected to be operated by the lever J, is supplied to the machine through the main supply passage K.

In this instance a valve block L and a cap piece 0 fitted together form a valve casing, removably held within the rearward end of the cylinder by the handle or back head F.

A hollow cylindricalrfluid actuated differential distributing valve P. in all respects like the valve shown in said Patent No. 1,528,? 81 and functioning in the same manner, is slidable longitudinally wlthin the valve casing in axial alignment with the cylinder A and is formed with a bore Q slightly larger than the bore of the cylinder, to permit the piston C to pass through the valve on its rearward stroke. In this instance the valve P controls the admission and exhaust of motive fluid from both ends of the cylinder by means of suitable ports 10o and passages in the cylinder, the head block L and the cap piece 0, only so much of the distribution features and ports and passages for operating said valve being shown as will indicate the type of valve sincethe valve itself forms no part of this. invention.

The neck V of the valve, located forwardly of the head T, is for controlling the supply to the forward end of "the cylinder through the combined supply and. exhaust passage TV in the cylinder communicating with the forward end of the cylinder through the port- X, and this neck V is also for controlling the exhaust from both ends of the cylinder through the exhaust passage Y preferably protected by a suitable exhaust deflector Z.

As the piston travels forwardly, as indicated in Figure 2, with the valve in forward position. the forward end of the cylinder may exhaust through the port X, passage lV, port 6 in the cap piece O, communicating with the groove in the cappiece 0 around the valve neck V and from said groove 7 through the )ort g in the cap piece to atmosphere" throng the exhaust passage Y. As the iston travels rearwardly, as indicated in igure 1, with the valve in rearward position, fluid is exhausted from the rearward end of the cylinder directly through the port and the exhaust port Y to atmosphere.

An additional groove 3 is formed in the cap piece'O forwardly of the groove 7 connecting the port g with an additional port 4 in the cap piece. A passage 5 in the cylinder wall affords comunication for exhaust fluid between the port 41 and a port 6 in the forward end of the cylinder at a point be yond the cylinder port X to permit exhaustfluid to surround the shank of the rivet set D. A groove 7 at this point connects the port 6 with an opposite port 8 in thecylinder, which port 8 is connected by the cylinder passage 9 with the atmospheric exhaust port Y.

The ports and passages described and numbered from 3 to 9 inclusive, form a by pass for exhaust fluid through which the exhaust fluid is conducted from a point at the rearward end of the cylinder forwardly through one ortion of the cylinder wall, thence througi a passage 7 around the forward end of the cylinder and rearwardly to the atmospheric exhaust ort Y through another portion of the cy inder wall for cooling the cylinder and the shank of the rivet set orot'her impact element.

It will be observed that the passage or groove in the cap piece O of the valve casing or cage is always opened to exhaust in either forward or rearward position of the valve P so that the by-pass described functions for cooling purposes both on the forward and rearward stroke of the piston.

Obviously by closing comunication between the groove 3 and the port y in the cap piece 0 by means of a Jlug or otherwise. the entire exhaust coulc be directed first to the forward end of the cylinder and then carried rearwardly to the exhaust port Y. if desired. The cooling means disclosed operates satisfactorily and well and has been found to accomplish the objects sought.

No special provision is necessary for inducing the flow of exhaus air through the bypass around the rivet set. other than the natural restriction of the exhaust through the groove 3 and small ports and -l and the provision of the usual exhaust deflector of ordinary construction. The restriction of the exhaust at port leading more directly to atmosphere is about the same as the restriction at the port l leading loss di rcctly to atmosphere, and as the deflector acts as a battle. also retarding or choking the flow, the exhaust air has two paths. and some of the air will take the more direct path and some will take the less direct path. depending on the amount of resistance to flow at the restricted ports g and at and in the exhaust passages.

I claim 1. In a pneumatic hammer, the combination of a cylinder, a reciprocating piston, a distributing valve, an atmospheric exhaust port for the cylinder at the rearward end of the cylinder. and means for permitting the exhaust fluid to flow from a point at the rearward end of the cylinder forwardly through one portion of the cylinder wall. thence through a passage around the forward end of the cylinder and then rearwardly to said atmospheric exhaustport through another portion of the wall, for cooling the cylinder.

2. In a pneumatic hammer, the combination of a cylinder, a reciprocating piston, 11 distributing valve. an atmospheric exhaust port for the cylinder at the rearward end of the cylinder, and means for by-passing a portion of the exhaust fluid from a. point at the rearward end of the cylinder for wardly through one portion of the cylinder wall, thence through a passage around the forward end of the cylinder and then rearwardly to said atmospheric exhaust port through another portion of the wall, for cooling the cylinder.

3. In a pneumatic hammer, the cou'ihiuation of a cylinder, a reciprocating piston a distributing valve, an atmospheric exhaust port for the cylinder at the rearward end of the cylinder. exhaust passages leading from said atmospheric exhaust port to and from the forward end of the cylinder wall, and a passage in the cylinder wall connecting the forward ends of said exhaust passages and encircling that portion of the cylinder wall into which the shank of the impact implement is adapted to extend, whereby the cylinder and the shank of said implement are cooled by said exhaust fluid.

4. In a pneumatic hammer, the combination of a cylinder, a reciprocating piston, a distributing valve controlling both the inlet and exhaust from both ends of the cylinder, an atmospheric exhaust port for the cylinder at the rearward end of the cylinder, and means for permitting the exhaust fluid to flow from a pointat the rearward end of the cylinder forwardly through one portion of the cylinder wall, thence through a passage around the forward end of the cylinder and then rearWardly to said atmospheric exhaust port through another portion of the wall, for cooling the cylinder.

5. In a pneumatic hammer, the combination of a cylinder, a reciprocating piston, a distributing valve controlling both the inlet and exhaust from both ends of the cylinder, an atmospheric exhaust port for the cylinder at the rearward end of the cylinder, and means for by-passing a portion of the exhaust fluid from a point at the rearward end pheric exhaust port through another por- 2.

tion of the wall, for cooling the cylinder.

6. In a pneumatic hammer, the combinatlon of a cylinder, a reciprocating piston, a

distributing valve controlling both the inlet and exhaust from both ends of the cylinder, an atmospheric exhaust port for the cylinder at the rearward end of the cylinder, exhaust passages leading from said exhaust port to and from the forward end of the cylinder Wall, and a passage in the cylinder wall connecting the forward ends of said exhaust passages and encircling that portion of the cylinder wall into which the shank of the impact implement is adapted to extend, whereby the cylinder and the shank of Eaioli implement are cooled by said exhaust In testimony whereof I have signed this specification.

VILLIAM FRANK ZIMMERMANN.

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