US756357A - Pneumatic hammer. - Google Patents

Description

v PATENTED APR. 5, 1904.

E. GUNNELL. PNEUMATIG HAMMER.

APPLIGATION FILED DEO. 17, 1900.

N0 MODEL.

n il. ill.

ivo. 756,35v.

UNITED STATES 1atented. April 5, 1904i.

PATENT OFFICE.

ELIAS GUNNELL, OF CHICAGO, ILLINOIS, ASSIGNOR OF ONE-HALF TO W. I. BABCOCK, OF CHICAGO, ILLINOIS.

PNEUMATIC HAMMER.

SPECIFICATION forming part of Letters Patent No. 756,357, dated April 5, 1904.

Application filed December 17, 1900. Serial No. 40,078. (No model.)

ATo all wlwwt'it may concern,-

Be it known that I, ELIAS GUNNELL,a citizen of the United States, residing at Chicago, in the county of Cook, in the State of Illinois', have invented a certain new and useful Improvement in Pneumatic Hammers, of which the following is a description, reference being had to the accompanying drawings, forming stant pressure, by the pressure of motive iuid intermittently admitted to its superior forward end or pressure area; while other features of my present invention are applicable to other types of tools, all as will be hereinafter more fully explained.

In the accompanying drawings, Figure lis a vertical longitudinal section of my hammer, with the piston in rearward position, and with the throttlecvalve controlling the admission of motive iiuid to the tool closed; Figure 2, a corresponding view with the throttle valve open,and with the piston driven to the forward limit of its stroke; Figure 3, a corresponding view illustrating a modified construction; and Figures 4. and 5 sectional details showing the split spring rings for holding the working tool in place.

The same letters of reference are used to indicate identical parts in the several views.

The cylindrical body of the tool is in Figures 1 and 2 composed of an inner cylinder A, a surrounding sleeve B, and an outer casing C, the latter having formed upon the under side of its rear end a suitable casting D for the throttle valve chamber and for the connection of the motive fluid supply-pipe, and upon the upper side of its rear end a curved arm E to which the upper end of the grasping handle F is hinged at a. The sleeve B is conned in the casing C (with its front end abutting against the front wall of the internal bore of said casing) by the inner cylinder A which .is provided with an annular shoulder at and the inner cylinder A is itself confined in the casing C by a screw-plug G screwed into the rear end of the casing C and abutting at its forward end against the rear end of the cylinder A. The plug G is provided with a peripheral flange c having ratchet teeth with which co-operates a spring catch d to hold the plug in the position to which it is turned.

The cylinder A is bored out to two different diameters to receive the piston composed of the enlarged front end or head H and rearwardly extending stem or body I, and at its forward end terminates short of the front end of the sleeve B to'form a chamber for the cylindrical valve J. The front end of the sleeve. B is thickened interiorly, thereby contracting its internal bore, 'and in this contracted portion of the sleeve lits the forward portion or body of the cylindrical valve J, while the rear end of the valve is, provided with an exterior annular enlargement or flange which fits and travels in the main bore of the sleeve B in front of the cylinder A, and is provided with a beveled surface as shown to co-operate with theseat formed for it by the front end of the cylinder A.

The front end of the casing C isprovided with a reduced central bore and bushing K, through which the shank of the rivet set or other working tool L passes and projects into the interior of the cylinder or front end of the piston chamber, within the valve J.

A long passage M terminates at its forward end in a port e extending through the thickened portion of the front end of the sleeve B,

and communicates at its rear end bya port f with the reduced rearportion ofthe piston chamber. When the valve J is in forward position, shown Figure l, and the piston in its rearward position, there shown, the port e' lis closed by the valve J and the port f by the 4 ward end of the piston chamber or internal bore of the cylinder, occupied by the valve J.

The forward portion of the cylinderA is provided upon its exterior with longitudinal grooves e' communicating at their rear ends with the interior of the cylinder by ports j, and the sleeve B and casing* C are provided in front of the cylinder A with exhaust ports O, which are open when the valve is in forward position, as in Fig'ure l, but Closed when the valve is in rearward position, as in Figure 2. Other exhaust ports or openings I?, extending through the cylinder A, sleeve B, and casing C at the rear end of the larger portion of the piston chamber, permit ingress and egress of air behind the head of the piston in the reciprocations of the latter.

The rear end of the cylinder A and screwplug Gr are bored out to form an enlarged chamber Q to which the motive fluid is constantly admitted when the tool is in operation through a circular row of ports 7c connecting it with a surrounding annular chamber 7c into which opens the main inlet passage controlled by the throttle valve located in the casting D and hereinafter described.,

In the position of the parts shown in Figure l the portion of the piston chamber in front of the piston is open to the exhaust through the ports O, and the piston will therefore be driven forward by the pressure of the motive fluid admitted to the chamber Q when the throttle valve is open. As the piston reaches the forward limit of stroke its head H will enter the valve J and contact with the shank of the tool L, and its rear end will simultaneously uncover the port g and permit the motive fluid behind the piston to pass forward through a passage N to the front end of the piston chamber and there act upon the front end of the cylindrical valve J and drive the latter rearward to the position shown in Figure 2, causing the beveled surface of its rear end to seat itself against the front end ofthe cylinder A and cut ofi' communication between the exhaust ports O and the interior of the cylinder. This rearward movement of the valve J will also uncover the port e, so that motive iiuid will pass forward through both of the passages M and N to the front end of the piston chamber and act upon the head H of the piston and drive the latter rearward.

As soon as it has moved rearward far enough for its stem I to close the portf the admission of live air to the front end of the piston chamber will be cut off, and the further rearward movement of the piston will be effected by the expansion of the live air previously admitted and the acquired momentum of the piston. Vhen the piston reaches the rearward position shown in Figure l and uncovers the ports y' the pressure within the piston chamber which has driven the piston rearward will pass through said ports and the grooves or passages/a' to the rear end of the valve J, and there acting upon a pressure area superior to that of the front end of the valve will drive the latter forward and uncover the ports O, permitting the pressure in front of the piston to escape and the piston to be driven forward again after its momentum has been ar. rested by the pressure behind it in the chamber Q.

In the particular construction shown in my former patent heretofore referred to the valve J was given its rearward movement by pressure constantly admitted to its forward pressure area through a long passage extending rearward through the cylinder wall and in constant communication with the pressure supply, and was driven forward by pressure intermittently admitted to its preponderating rearward pressure area. Under my present construction the valve is shifted in each direction by intermittently admitted pressure, and the constant pressure supply -passage mentioned is dispensed with. In both instances, however, the valve serves to control both the inlet and exhaust of the motive fluid at the front end of the piston chamber, but this is not essential, since in Figure 3 of my present drawings I have illustrated a valve which operates to control only the exhaust, the admission of the motive fluid being controlled by the piston itself.

In the construction shown in Figure 3 I provide a reservoir chamberRin the cylinder A, which communicates with the smaller bore of the piston chamber by ports 6, and by ports g with the passages N leading to the front end of the pistonchamber as in Figures l and 2. No passage corresponding to the passage M and having its front end controlled by the valve J is employed. As the piston reaches the forward end of its stroke and its head H enters the valve J and contacts with the shank of the tool L, its rear endl will uncover the ports g and admit the motive iluid to the chamber R and passages N, and thence to the front end of the piston chamber where it will operate to shift the valve J rearward, to the po sition shown in Figure 2, thereby cutting olf communication between the exhaust ports O and the interior of the piston chamber, and also serves to drive the piston rearward. The rear end of the stem I of the piston will cover and close the ports g at the beginning' of its rearward movement but the expansive pressure of the extra supply of motive fiuid in the reservoir chamber R, aiding that in the piston chamber, will serve to drive the piston on rearward, against the full pressure acting upon its smaller' rear end, until the head of the piston passes rearward of and uncovers the ports y', thereby admitting' pressure through the passages e' to the rear pressure area of the valve J, as in Figures l and 2, and driving' the latter forward again and opening' the exhaust ports O, to permit another forward stroke of the piston.

IOC

The passage 7c through which the motive fluid is admitted from the supply pipe to the chamber Q is controlled by a balanced throttle valve S of familiar spool form fitting in a sleeve or bushing T driven in a bore in the casting D. The forward head ofthe valve controls the ports mr in the sleeve T, which aord communication between the interior thereof and a chamber U formed in the casting D around the sleeve T and communicating with the main inlet V to which the supply-pipe is connected, and the interior of the sleeve T communicates by a port n with the passage 7c leading to the chamber Q. A strong coiled spring W located in the front end of the sleeve or bushing T and acting against the forward head of the valve presses the latter rearwardly and tends to hold it in the position shown in Figure l, with `its forward head closing the ports m and cutting off the supply of motive fluid to the tool.

The handle F, which, as heretofore described, is hinged at its upper end at a to the arm E projecting upwardly and rearwardly from the rear end of the cylinder, has tightly driven into a suitable bore in its lower end a forwardly extending rod or pin Xwhose front end is adaptedfto Contact with the rearwardly projecting'stem of the throttle valve S, whereby pressure upon the handle F, when the work ing tool L is pressed against the rivet or other work, willforce the valve S forward in its chamber, against the resistance of the spring W, and open the ports m and admit motive fluid to the tool.

The arm E to which Vthe upper end of the handle is hinged extends rearwardly, beyond the pivot a, to the dotted line a', and the handle is provided with a corresponding slot to receive and embrace this rearwardly project- .ing end of the arm E. The rear wall of this slot is indicated by the dotted line b', Fig. 2, and its contact with the rear end a of the arm E limits the swinging movement of the handle F upon its pivot a, and consequently limits the rearward movement of the valve S under the stress of the spring W. For the purpose of adjustably limiting the forward movement ofA the lower end of the handle, and consequently regulating the opening movement of the valve S, the forwardly projecting lower end of the handle F is interiorly threaded to receive a nut Y which is provided upon its front end with an outwardly projecting flange Z which lits between the forward end of the handle and the rear side of the casting D containing the valve chamber and valve and contacts with said casting to limit the forward movement'of the lower end of the handle and consequent opening movement of the valve when pressure is applied to the handle. By turning this nut in one direction or the other the movement of the handle and degree of opening of the valve effected thereby may be regulated as desired. The flange Z of the nut cgi has a milled exterior to enable it to be readily turned by the operator to effect the desired adjustment.

The spring W is preferably of such strength as to be overcome, and the valve permitted to be opened, only by pressure upon the handle sufficient to hold the tool up to its work, so that no inadvertent or accidental opening of the valve is liable to occur. Instead of the spring W the valve may be constantly pressed rearward by motive fluid admitted to a closed chamber in front of the forward head of the valve through a minute passage or leak constantly communicating with the main inlet V.

In the construction shown in Figure 3 the casting D, cylinder headG and curved arm or handle support E are formed integrallywith each other and separate from the cylindrical body or casingof the tool and screwed upon the rear end of the latter, being provided with an interiorly threaded, forwardly projecting sleeve E adapted to receive the exteriorly Y threaded rear end of the cylinder or casing. The inner cylinder A is in this instance provided upon its rear end with a circumferential flange which .is clamped between the rear end of the casing C and cylinder head Gr when the latter is screwed into position upon the rear end of the tool. The outer casing or cylinder of the tool is provided with a circumferential flange C provided upon its rear face with ratchet teeth with which co-operates a spring catch C to keep the parts from becoming unscrewed. The remainder of the construction is substantially thesame as in Figures l and 2,' vexcepting that the inlet passage It opens directly into the rear end of the piston chamber behind the piston, instead of opening into an enlarged chamber Q, as in Figures 1 and 2.

I am aware that it isnot broadly new to control the throttle valve of pneumatic ltools by pressurel applied to the tool or the handle thereof in holding it up to its wor-k; but I believe I have produced a simpler and more eilicient construction than those heretofore employed, and one in which the advantage of a large and direct inlet for the motive fluid, controlled by the throttle valve, is attained to a greater degreethan heretofore.

In the present instance the rivet set L or other working tool is removably held in povsition in the front end of the cylinder by means of a 4split spring ring K fitting inl an annular chamber I formed for it in the bushing K and surrounding and frictionally engaging the shank of the tool L, Figures 4 and In assembling the parts the ring K is compressed sufficiently to permit its insertion through the bore of the bushing K until it comes opposite the recess or chamber K, whereupon it springs outward into said recess. Upon then inserting the shank of the tool L and forcing it rearward its rear end will slightly expand the ring K and the shank of the tool will pass on through the ring until it IOO TIO

reaches its innermost position. The frictional grip of the ring upon the shank of the tool will prevent any accidental displacement of the latter. For the purpose of preventing the working tool being forcibly expelled by any inadvertent blow of the piston when the tool is not held up to its work I make the recess K in Figure 5 taperingin form, and provide a corresponding beveled ring K. rlhis ring frictionally grips the shank of the working tool and prevents its accidental displacement, as does the ring K in Figure 4; but if the working tool be forcibly driven forward by the piston when not pressed against the work the beveled ring K' in Figure 5, moving' forward with the shank of the tool and engaging the beveled or tapering wall of the recess K", will be wedged inward and compressed upon the shank of the tool and so firmly grip the latter as to prevent its further forward movement.

In either case the working tool may be readily removed by giving it a twisting movement and steadily pulling it outward, and can be reinserted in the manner before explained.

Having thus fully described my invention, I claim- 1. In a pneumatic hammer, the combination, with the cylinder and the throttle valve controlling the admission of the motive fiuid thereto, of a hinged grasping handle co-operating with said valve to open the same when the tool is held up to its work by pressure applied to said handle.

2. In apneumatichammer, the combination, with the cylinder and the throttle valve controlling the admission of the motive iiuid thereto, of a grasping handle hinged at one end to one side of the tool at its rear end and co-operating at its opposite free end with the throttle valve at the opposite side of the tool to open said valve when the tool is held up to its work by pressure applied to said handle.

3. In apneumatichammer, the combination, with the cylinder or body of the tool provided at one side of its rear end with an outwardly projecting arm or handle-support, and at its opposite side with a casting containing a throttle valve chamber, a throttle valve located in said chamber and controlling the admission of the motive fluid to the cylinder, and a grasping handle hinged at one end to the arm or handle-support and co-operating at its opposite free end with the throttle valve to open the same when the tool is held up to its work by pressure applied to said handle.

4. In a pneumatic hammer, the combination, with the cylinder and the throttle valve controlling the admission of the motive fluid thereto, of ahinged grasping handle co-operating with said Vvalve to open the same when the tool is held up to its work by pressure applied to said handle, and means for regulating the extent of such opening of the valve by said handle.

5. In a pneumatic hammer, the combination, with the cylinder and the throttle valve controlling the admission of the motive fluid thereto, of ahinged grasping handle co-operating with said valve to open the same when the tool is held up to its work by pressure applied to said handle, and an adjustable stop or contact device interposed between the handle and cylinder or fixed part thereof to limit the movement of the handle in opening the valve.

6. In apneumatic hammer, the combination, with the cylinder and the throttle valve controlling the admission of the motive fluid thereto, of a grasping handle hinged at one end to the rear end of the cylinder or body of the tool at one side thereof', and co-operating at its opposite free end with the throttle valve on the opposite side of the tool to open the same by pressure applied to the handle, and an adjustable stop or contact piece interposed between the free end of the handle and the cylinder or fixed part thereof to limit the movement of the free end of the handle in opening the valve.

7. In a pneumatic hammer,the combination, with the cylinder and the throttle valve controlling' the admission ofthe motive fluid thereto, of a grasping handle hinged at one end to the rear end of the cylinder or body of the tool at one side thereof, and co-operating at its op- -posite'free end with the throttle valve on the opposite side of the cylinder to open the same by pressure applied to the handle, and an adjustable nut interposed between the free end of the handle and the cylinder or a fixed part thereof to limit the movement of the handle in opening the valve.

8. In a pneumatic hammer, the combination of the cylinder provided upon one side of its rear end with the arm or handle-support E and upon the opposite side thereof with the casting D containing the throttle valve chamber, the valve S located in said chamber and controlling the admission of the motive fluid to the cylinder, the grasping handle F hinged at one end to the arm E and co-operating at its opposite free end with the valve S to open the same when the tool is held up to its work by pressure applied to said handle.

9. In a pneumatic hammer, the combination of the cylinder provided upon one side of its rear end with the projecting arm or handle-support E, and upon the opposite side thereof with the casting D containing the throttle valve chamber, the throttle valve S located in said chamber and controlling the admission of the motive fluid to the cylinder, and the grasping handle F hinged at one end to the arm E and provided with a shoulder or contact surface 7) co-operating with the like shoulder or contact surface c upon the arm E, and co-operating at its opposite free end with the throttle-valve S to open the same.

10. In a pneumatic hammer, the combination IUO IIO

of the cylinder provided upon one side of its rear end with the projecting arm or handlesupport E and upon the opposite side thereof With the casting D containing the throttle valve chamber, lthe valve S in said chamber controlling the admission of the motive fluid to the cylinder, and the grasping handle F hinged at its upper end to the arm E and provided at itslower end With the pin or rod X co-operating With the valve S.

ll. 1n a pneumatic hammer,the combination of the cylinder provided upon one side of its rear end With the projecting arm or handlesupport E and upon the opposite side thereoil With the casting D containing the throttle valve chamber, the valve S in said chamber controlling the admission of the motive iuid to the cylinder, the grasping handle F hinged at one end to the arm E and provided at its opposite end With the pin or rod X co-operating With the valve S, and the tubular regulatng nut screwed into the free end of the handle F and provided With the flange Z in'- terposed between said handle and the cast# ing D.

ELIAS GUNNELL.

Witnesses:

YEDWARD RECTOR,

J oHNl H. BERKSTRESSER.

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