US776671A - Pneumatic hammer. - Google Patents

Description

liNiTEn STATES Patented December 6, 1904.

MAX MAXIMILIAN, OF BUFFALO, NEW YORK.

PNEUMATIC HAMMER.

SPECIFICATION forming part of Letters Patent N o. 776,671, dated December 6, 1904. Application filed April 13, 1904. Serial No. 202,902. (No model.)

l To al?, whom it may concern.-

Be it known that I, MAX MAXIMILIAN, a subject of the Emperor of'Germany, residing' at Buifalo, in the county of Erie and State of New York, have invented new and useful lmprovements in Pneumatic Hammers, of which the following' is a specification.

This invention relates to pneumatic hammers of that class in which the reversing-valve moves axially with reference to the piston.

The objects of this invention are to improve the construction of the reversing-valve mechanism, so as to increase the number of strokes of the piston within a given time and to permit of making' repairs easily and also to provide simple and eiiicient means for automatically-lubricating the working' Vparts of the hammer.

In the accompanying drawings, consisting' of two sheets, Figure L1 is a longitudinal section of my improved pneumatic hammer, the ports and passages being shown diagrammatically for convenience in illustrating' the invention. Fig. 2 is a fragmentary view similar to Fig'. 1, showing the reversing-valve in a shifted position. Figs. 3 and 4 are crosssections in lines 3 3 and 4 4L, Figs. land 2, respectively.

Similar letters of reference indicate corresponding parts throughout the several views.

A represents the main or power cylinder of the hammer; B, the piston reciprocating' therein; C, the tool or die fitted in the lower or rear end of the cylinder; D DQ the front and rear sections of the reversing-valve chest mounted on the front end of the cylinder; E, the head or cap inclosing the Valve-chest and having a screw connection with the cylinder, and F the handle applied to the outer side of the cap. Above the upper section of the valve-chest the cap is provided with an air-distributing chamber G, and the handle is provided with a passage (j, which connects the distributingehamber with a tube or other conduit that supplies compressed air. This passage may be controlled by a throttle-valve of any suitable construction, that shown in the drawings consisting of a plunger H, arranged in an opening which intersects the supply-passage g and having a reduced part or neck L, a spring t, whereby the plunger is normally shifted lengthwise, so that its full part closes the supply-passage, and a trigger or thumb-piece 7b2, whereby the plunger may be shifted to bring its contracted part in line with the supplypassage for opening the same and admitting air into the distributing-chamber.

The valve mechanism for alternately admitting the compressed air and exhausting' the spent air `from opposite ends of the cylinder for causing the piston to reciprocate therein is constructed as follows: fithin the rear or `lower section of the valve-chest is formed a valve-chamber composed of a large upper or front part .l and a small-lower or rear part l. The side walls of the upper and lower parts of the valve-chamber are constructed to form cylindrical valve-seats, which are preferably axially in line or parallel with the axis of the power-cylinder. The top or outer end of the large valve-chamber is formed by the upper or front section of the valve-chest, while the bot-tom of the lonf'erchamber is formed bythe solid lower part of the lower section. The distributi11g-valve, which reverses the connection of the ports leading' to opposite ends of the power-cylinder, consists of a large-area valve-piston J, arranged in the upper or large part of the valve-chambcr, and a small-area \f'alve-1'Iiston J", arranged in the lower or small part lof the valve-chamber and connected with the large-area mlve-piston by a contracted neck or reduced party'. The compressed air is preferably conducted to the lower end of the small part of the valve-chamber by a plurality of passages f, cach of which consists of a longitudinal part extending from the distributing-chamber downwardly through both valve-chest sections outside of the valve-chamber, and a transverse part extending from the lower end of the longitudinal part to the lower end of the valve-chamber. The inner or lower ends of the several passages all terminate in a main port 7:', which opens upwardly into the central part of the valvechamber at the lower end thereof. That pal't of the bottom of the valve-chamber around the lower central air-inlet forms an annular shoulder with which the marginal part of the lower end of the distributing-valve engages in the lowered position of the same. A short distance above the lower end the small part of the valve -chamber is provided with an annular reversing-port which is connected by a plurality of oblique reversing-passages L with the upper end of the power-cylinder. These passages open through the lower side of the valve-chest, so as to connect the port l directly with the upper end of the cylinder and serve alternately as air-supply conduits and as exhaust-conduits for this end of the power-cylinder. Above the port Z the small part of the valve-chamber is connected with the atmosphere by a pluralityT of exhaust-passages m, each of which consists of a transverse part arranged in the lower section of the chest and opening at its inner end into the small part of the valve-chamber, and a longitudinal part extending from the outer end of the transverse part through the side of the lower chest-section and the power-cylinder and opening into the atmosphere adjacent to the lower end of the cap, as shown in Fig. l.

In vthe elevated position of the distributing or reversing valve (shown in Fig. l) its lower piston is arranged between the inner end of the exhaust-ports m and the reversing-port Z, whereby the passages 71: and L are connected, and compressed air is conducted into the upper end of thepower-cylinder for propelling the piston downwardly or forwardly with a working stroke. In the depressed position of the reversing-valve (shown in Fig. 2) its lower or small piston is arranged below the reversing-port Z, whereby the passages L are connected with the exhaust-passages m, and

\ the spent air in the upper end of the cylinder is permitted to vent into the atmosphere during the subsequent upward or idle return stroke of the piston.

Vhile the piston is moving forward or downward with a working stroke the air in front of the same is freely displaced into the atmosphere through the exhaust-passages N N. rIhe exhaust-passage N has a port n, which opens into the lower part of the powercylinder at a distance from its lower end, while its outer end opens into the atmosphere, preferably by communicating with one of the exhaust-passagesm. The exhaust-passage N' communicates at its lower end with the extreme lower end of the power-cylinder by a port a', while its upper end connects with the upper large part of the valve-chamber by a port n2, which opens through the lower part of the large cylindrical valve-seat thereof. During the descent of the piston while the reversing-valve is elevated, as shown in Fig. l, part of the air below the same is expelled directly to the atmosphere through the exhaust port and passage a N and part of it indirectly to the atmosphere by passing successively through the port a', passage N', port n?, upper and lower parts I I of the valve-chamber, and exhaust-passages m. The port n of the exhaust-passage is so located that the same is covered by the piston during the last part of its downward or forward stroke, whereby the final portion of the air below the piston is expelled from the power-cylinder solely through the reversing-passage N and exhaust passages and ports connected therewith and prevents cushioning of the blow of the piston against the tool.

Then the piston reaches the lower end of its working stroke, its rear end has passed below a reversing-port 0, which connects by a passage 0't with a port 02, opening' into the top of the upper large part of the reversing-valve chamber, this passage being formed partly in the cylinder and the two sections of the valvechest, as shown. The instant the piston uncovers the reversing-'port 0 the compressed air passes from the cylinder upwardly through passage 0 and into the upper large part of the valve-chamber and exerts a downward pressure against the top of the upper valve-piston. Inasmuch as the pressure of the air against the top of the large-area valve-piston preponderates over the vair-pressure against the under side ofy the small-area valve-piston, these pistons are shifted from the elevated position shown in Fig. 1 to the depressed position shown in Fig. 2. Vhen this occurs, the connections ofthe compressed air and the exhaustair are reversed for causing the piston to be raised by admitting compressed air underneath the piston and exhausting the spent air above the piston into the atmosphere. For this purpose air inlet and exit ports p p are provided, which open through the upper part ofthe large cylindrical piston-valve seat, preferably on diametrically opposite sides thereof, and connect, respectively, .with one of the airpassages it' and the passage N.

When the reversing-valve is in its depressed position, the compressed air passes from one of the passages throughthe inlet-port p,

thence across the valve-chamber above the upper valve-piston, thence out through the outlet-port p into the passage N', and thence into the lower end of the cylinder, thereby lifting' or moving the piston therein with a return stroke. The full force of the compressed airis directed against the piston during the first part of its return or upward movement. The instant, however, that the piston has moved backwardly or upwardly sufliciently to uncover the exhaust-port 7L the force 0f the compressed air, leading to this end of the power-cylinder, is weakened to such an extent that the compressed air, which constantly presses upwardly against the smallarea valve-piston, now preponderates overthe downward pressure exerted against the largearea valve-piston, whereby the reversingvalve is shifted from the depressed position shown in Fig. 2 to the elevated position shown in Fig, l. During the first part of the upward movement Qf the piston the air in the upper IOO ILO

part of the cylinder is expelled through the passages L, port Z. and passages m; but du ring' the last part of this movement the compressed air enters the upper end of the cylinder, owing to the reversal of the valve, thereby causing the piston to be cushioned at the end of its upward movement and avoiding jarring of the hands of the operator who is holding' the tool.

When the valve has been thus reversed, the

operation ofthe parts is repeated continuously in the manner before described while the throttle-valve is open.

By forming an annular shoulder at the bottom of the valve-chamber around the central air-inlet the area of the lower end of the small valve-piston which is exposed to the air-pressure is less than when the valve is slightly raised, thereby enabling' the valve to be held securely in its lowered position and. permitting the piston to complete its downward stroke and deliver an effective blow, but permitting the valve to be reversed quickly an instant after the same has started in its upward movement.

The valve-pistons are preferably constructed in the form of cups, the lower small one opening downwardlynand the upper large one opening upwardly. By this construction of the reversing-val ve the compressed air entering the lower end ofthe valve-chamber centrally through the main port;I and air entering the upper end of the valve-chamber through the port o2 is caused to spread uniformly over the entire area of these pistons and move the same up or down in a straight line without any tendency to tilt the same, which would cause the valve to wear unnecessarily and also reduce the efficiency of the hammer.

By arranging the outlets of the exhaustpassages adjacent to the lower end of the cap the same are not liable to be closed by the hand of the operator and cause interference with the working' of the hammer, nor `is the workman so liable to be spattered with oil or other material which may be ejected by the blast of the escaping air.v as would be the case if the exhaust-outlet were in the cap.

By making the upper seat of the reversingvalve wholly in the lower section of the valvechest the upper valve-piston can be ground more accurately to its seat.

In order to prevent the reversing-valve from getting stuck on the dead-center by grit or other impurities in the air, and thus leaving the tool in a balanced and inoperative condition, one or more springs g are provided, which tend constantly to move the reversing-valve toward one end of its stroke. As shown in Figs. l and 2, these springs are arranged between the upper valve-piston and the top of the valve-chamber and operate to hold the reversing-valve yieldingly in its lower position. .ln this position of the reversing-valve the ports are so connected that air is admitted to the lower end of the cylinder for beginning the operation of the piston with a liiaclnvard. stroke. By means of these springs the valve can never become stuck at a place where it is about to reverse the air connections of the cylinder, thereby avoiding loss of time incident to adjusting' tools as ordinarily constructed in which this dilliculty frequently occurs. The reversing-port o2 at the upper end of the valve-chamber is made somewhat smaller than the port yf, so that the air entering through the inlet-port y) and moving in the direction of least resistance will favor the port p, from which latter t-he air passes to the cylinder underneath the piston, thereby preventing the air from being lead backwardly through the port 02 and passage o' into the cylinder above the piston and balancing the pressure on the piston.

For continuously supplying lubricant to the hammer whenever the same is in operation lubricating means are provided which are operated automatically and are controlled by the working parts of the hammer, such as the re-,

versing-valve or the piston. The preferred. means for this purpose (shown in the drawings) comprises a reservoir or chamber R, arranged iu the upper section of the valve-chest and having an open top through which the same is filled with. lubricant, such as oil or grease, this opening' being normally closed by a screw plug or cover r. ln its bottom the reservoir is provided with a discharge-opening t', which leads into the upper end of the valve-chamber and which is constructed at its upper end to form a conical valve-seat. l represents a conical feed-valve arranged in the reservoir and movable axially toward and from the seat in the opening s for controlling the discharge of lubricant. This lubricatingvalve is moved downward against its seat for IOO closing the opening s by means of a spiral I spring t, seated at its opposite ends on a boss t', formed on the upper end of the oil-valve, and a similar boss rfi, formed on the under side of the reservoir-cover. The lubricatingvalve is provided at its lower end with a depending stem which projects downwardly into the reversing-valve chamber. On the upper side of the reversing-valve is arranged a tappet u, which adapted to engage the lower end of the stem of the lubricatingvalvc and lift the latter from its seat during every upward movement of the same and leaves said stem to permit the lubricating-valvc to engage its seat during cach downward nievement of the reversing-valve. By this means the lubricating-valve is momentarily opened during every reciproeation of the reversingvalve, and small quantities of oil are continuously supplied to the working parts of the hammer, thereby insuring ypositive and uniform lubrication thereof with a minimum amount of oil. The tappet 'a preferably consists of a screw which engages with a threaded opening' in the large-area valve-piston and IIO has its head arranged in the necl of the reversing-valve, which is made hollow for this purpose. By constructing the tappet in the form of a screw the same can be readily adjusted for regulating the amount of oil, which is supplied intermittently, and the wear upon the parts may also be conveniently taken up.

I claim as my invention- 1. A pneumatic hammer comprising a power-cylinder, a valve-chest having an integral bottom and a separable top and containing a valve-chamber having a large upper cylindrical valve-seat, a small lower cylindrical valve-seat, a lower main air-inlet port opening` centrally into the lower end of said chamber, an annular shoulder formed at the lower end of said chamber around said central inlet-port thereof, an intermediate main airinlet port opening into the small valve-seat above said lower central inlet-port and connected by oblique passages with the upper end of the cylinder, an exhaust-passage open- `ing into the lower valve-seat above said intermediate port, an upper main air-inlet port connecting the upper part of said large valveseat with the air-sup ply, another upper main air-inlet port connecting the upper part of said large valve-seat with the lower end of said cylinder and an upper exhaust-port connected with the lower part of said large valveseat, and an imperforate main distributingvalve arranged in said chamber and having a lower small valve-piston constructed in the form of a downwardly-opening cup and coperating with said small valve-seat for connecting said main lower air-inlet port either with the main intermediate air-port or with said lower exhaust-port and having' the marginal part of its lower end constructed to bear against said annular shoulder, and an upper large valve-piston constructed in the form of an upwardly-opening cup and cooperating with said upper large valve-seat for connecting said main upper air-inlets or said upper and lower exhaust-ports, substantially as set forth.

2. A pneumatic hammer comprising a powercylinder, a valve chest containing a valve-chamber and ports for connecting' opposite ends of said cylinder with the air-supply and withthe atmosphere, a valve controlling said ports,and a spring bearing constantly against the valve and operating to yieldingly hold said valve at one end of its movement, substantially as set forth.

3. A pneumatic hammer comprising a power-cylinder, a valve-chest having' a chamber containing a large upper cylindrical valveseat, a small lower cylindrical valve-seat and ports connecting' opposite ends of the cylinder with an air-supply and with the atmosphere, a valve controlling said ports and having a large upper valve-piston which cooperates with said upper valve-seat for controlling' the admissionl and exhaust of air from the lower end of the cylinder, and a lower small valve-piston which cooperates with the lower valve-seat for controlling the admlsslon and exhaust of air from the upper end of the cylinder, and a spring` bearing constantly at its opposite ends against the upper end of said valve and the top of the valve-chamber and operating to hold the valve yieldingly in its depressed position, substantially as set forth.

4. A pneumatic hammer comprising a power-cylinder, means for controlling the air connections with said cylinder comprising a valve-chamber and a distributing-valve reciprocatin g in said chamber, an oil-reservoir having an outlet which opens into the top of said chamber, and a lubricator-valve which controls said outlet-opening' and which is engaged by the upper end of said distributing-valve during every upward stroke of the same for lifting the lubricator-valve from its seat, substantially as set forth.

5. A pneumatic hammer comprising a power-cylinder, a piston, a valve-chest having a valve-chamber in its lower part, a lubricatorreservoir in its upper part and a lubricatordischarge opening arranged in the bottom of the reservoir and opening into said chamber, an air distributing valve arranged in said chamber and operating' to connect the opposite ends of said cylinder alternately with the air-supply and with the atmosphere, a lubricator-valve cooperating with a seat in said discharge-opening for controlling the escape of lubricant from the chamber and having a stem at its lower end and a boss at its upper end, a cover applied to said reservoir and having a boss on its under side, a spring {itted at its ends on the bosses of said lubricator-valve and cover, and a tappet cooperating with the stem of said lubricator-valve for opening the same and consisting of a screw arranged on the airvalve, substantially as set forth.

Witness my hand this 9th day of April, 1904.

MAX MAXIMILIAN.

Witnesses:

THEO. L. Porr, EMMA M. GRAHAM.

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