US935634A - Pneumatic hammer. - Google Patents

Description

W. BAXTER, JR.

PNEUMATIC HAMMER. APPLICATION YILED MAR. 12, 1906.

Patented Oct. 5, 1909.

INVENTOE A TTOHNE Y6.

To all whom itmay concern:

UNITED. srarns Parana onnrcn.

WILLIAM BAXTER, JR, or JERSEY-CITY, new JERSEY.

PNEUMATIC HAMMER.

Be it known that I, WILLIAM BAXTER, J12, a citizen of the United States, residing in Jersey City, in the-eounty of Hudson and State of New J erse'y, have invented certain new and useful Improvements in Pneumatic Hammers, of which the following is :1V specification;

The present invention relates to pneu matic hammers or similar reciprocating tools, and the object of the iiivei'ition is to provide improved means for regulating the force of the blow and the velocity of the hammer. I

Another object 9i? the invention is to so construct the actuating'valve that it will. at the same time act as a throttle valve. Other and further objects will appear from the following specification and will be more particularly pointed out in the annexed claims.

In the accompanying drawing-Figure 1 is a longitudinal section through the entire hammer; Fig. 2 is a section through-the valve chamber,' on the line a-a, Fig. l, the valve and the parts cooperating therewith being removec; Fig. 3 is a section on the line b-b, Fig. 1,.with the valve removed;

Fig. 4 is a section on the line cc, Fig. 1; Fig. 5 1s a bottom view of the cylinder cap; Fig. 6 1s a side vlew of Fig. 5; Fig. 7 1s a top View of Fig.5; Fig. 8 is a side view of the actuating valve, partlyein section; Fig.- 9 shows one of the stop plungers, and F 1g. 10 shows a modified form 01' plunger and one of the valve chamber heads.

1 is a casing which is formed in the shape of a handle at the upper end, and at the lower end is shaped to receive the valve and the upper end of the working cylinder.

2 and 3 represent the working cylinder 'which preferably is made in two'parts secured'together by screws 58, to simplify the construction of the ' ports 30 and 31, but the cylinder may be made solid and holes may be drilled therein to form the ports.

4 istheplunger and 5 is the combined actuating and throttle valve. The valve chamber is nfieferab ly provided with. a lining 6 to increase the durability of the tool.

7 and 8 are valve chan'iber heads, and 9 and 10 are stop plunger-s having stems 59 and enlarged inner ends 37 provided to limit the movement of the valve in either direction. i

Specification of Letters Patent. i Application filed March 12,

12 is the lower head of the working cylin- Iatented Oct. 5, 1909.

1906. Serial No. 305,635.

der, and 13 is thesha'nk of the tool which is driven forward by the lower end 51 of the plunger 4:; i

14- is the inlet through which com'n'essed .air passes to the tool,.15 and 16 are levers through which the operator moves the plunger 10,-and 17, 18, are levers through which he moves the plunger 9, all these levers being pivoted on studs 19.

g 20 and- 21 are recesses in the sides of 1, in which the ends of 0 and 10 are located so as to be protected against external injury.

22 is the large end of the valve chamber and is the .small end which is provided with an abutment for the head 8. I

24-, and 26, are ports provided in the valve chamber and 11 is the cylinder cap which isprovided with ports 27 and 28, in its upper side.

' 29 is a projection on the lower side of the cap 11 which serves to make a tight joint against the end of the cylinder, and also to "form a port 54.

30 and 31 are ports'in the cylinder, thefirst connecting the lower end 52 with the ported, and the latter connecting an annular port 34 surrouiuling the cylinder with a port 57 provided in the wall of the cylinder.

32 is an annular port surrounding the cap 11 and connecting the port 27 with the cham- 'ber into which the inlet 14 opens.

and 36 are ports that serve to connect the port 3 1 with a space 43 between the head 7 and the left end of the valve 5.

37, 37 are enlarged ends of the stop plunger-s t), 10 that fit close enough into the depressions in the enlls of the valve to act as cushions and thus prevent the valve from strikingviolently against them, but they, do not fit air tight.

38, 3t) and 40 are the piston portions of the valve 5, whiclnare connected with each other by necks 41,41. The portions 38 and '39 are of the same diameter while the portion 10 is of less diameter than the other portions.

42 isa small portthat connects the port; 28 with the space 43, and 44 is an exhaust port that connects with the port 24. when the .valve moves far enough to the left. 415 are holes through cap 11 that connect the port 28 with the port 54:. r

46 are pins and 47 are holes n'ovided to hold the cap 11 in a fixed position with relation to the casing 1. l r 48 is acylindrical depression in the upper The operation of the hammer is as follows: If the levers 15, 16 and 17, 18 are .in

the position shown in Fig' 1, and the inlet 14 is connected with a source of.compressed air, the hammer will use the maximum ainount of a-irand will make the maximum number of strokes in unit time and strike the maximum blow. Thelevers "17, 18 are nor mally in the-position shown in Fig. 1, while the levers 15, 16 are held in this position by the thumb of the operator andagainst the action of a spring 55 The stop 'plungers 9-10 are forced outwardly against levers 18 and 115 respectively by spiral springs, surrounding the stems 59 as clearly shown. When it is desired to stop the tool, the operator releases his hold on the lever 16 and the outer end of the lever is thrown upward bythe spring '55, and this movement swings the lower end of the lever 15 to the right until the enlarged end 37 of the plungei lt) lies against [the valve 5 and prevents the movement of the valve. The compressed air coming from the source 14 passes through the chamber 33 and the ports 32, 27 and 26 to the space between the pistons 39and of the valve, and as the former is larger than thelatte'r, there is an excess of-pressure acting to move the valve to the left, but it cannot move until the operator depresses the lever 16 If the lever 16 is depressed to the position shown in'Fig. 1, the valve 5 will be free toiniove to the left until it strikes the enlargedend 37 of the plunger 10. Then it so moves, valve piston 39 will pass to the left and thus open connection between the ports 25 and 26, andthe compressed air will pass to the upper, end of the cylinder. If the plunger 4 is at the top of the cylinder, it will be forced down to the'position shown'in Fig. 1, by the compressed air. As soon as it is far enough down to uncover the port 57, the air will pass to the port 31, thence through the ports 34, 35 and 36 to the space 43between. the head 7 and the valve piston 38. The pressure .on the left side of the piston 38 will now balance the pressure on the right side of the piston 39 and the unbalanced pressure against the left side of the piston 40 will, therefore, force the valve to the right to the position shown in Fig. 1 When the valve reaches this position, the compressed air in the upper end of the cylinder will pass through the ports 25,24, 28

and 30 tdthe'space 52 at; the lower end of. .the cylinder, and 'if t'here -i's '-air ,tight con nection between the shank 13 and the cylinrler end, the pressure'will force thepluniger upper en as the end 50 is larger than the 4. upwardy,

. When the plunger 4 has been forced nearly to the uppermost position the p lower edge of the head -50 uncovers the ex-' haust port53 and permits the air to escape from the cylinder. port 53 is connected with the port 57,

At the same time, the

through the neck 49, so that the compressed air in the space 43 is also exhausted and thus the pressure is relieved at this end of 7 5 the valve, and the pressure on the right side.

of the piston 38 is unbalanced so that the valve is now moved tothe left, readvto repeat the cycle.

Fromvthe above derstood that if the valve. is not perfectly air tight, the compressed air which has passed to the space 43through the port 57 ,wi'll soon leakout after the portv 57 .is covered by theplunger 4 on: the return stroke, hence the valve would be forced over to the left before description, it will be nn the plunger 4 reached the upper position.

The result ofthis would be that the full stroke of the plunger 4 wouldwnot be obtained. To prevent this occurrence, the small port 42- is provided which connects the port 28 andthe space 43 so that'the pressure in the space 43 may be maintained after the covered by the plunger 4 on the port 57 is It will also be seen that if'the upstroke.

valve piston 40 does not fit perfectly, the

space between the piston 40, and the head 8 would gradually be filled with compressedair and then the valve would not operate; To prevent this trouble, the stop plunger '9 does not fit tightly against the head 8, but portions are cut awa in the head 8 at the upper side of the'p ungei 9, as shown in Fig. 1.

The amount of air that passes to the working cylinder, determines the force with which the plunger 4 is driven forwardly, that is,

the force of the blow upon the shank 13.

The amount of air is controlled by/theextent to whichuthe'port 25 is uncovered-by the valve when it moves. to the left ndthis movement of the valve isicontrolle by the positionof the stop plunger 10; hence, the] force of the bl w can be increasedor. de;

creased by the extent to which the operator depresses lever 16. Thus through the proper manipulation oflever "16, the force of the blows struck by the hammer can be regulated. Y Q

. The velocity at which the plunger 4, will move on the backward stroke, that is;-f1 .om

the head 12 to the cap 11, dependson the velocity with which the compressed air can, pass from the upper tOdlliGfQWQI end of the cylinder, and this velocity will depend upon the extent to which the port 25 is uncovered by the valve 5 when the valve moves to the right. It will be seen that if the operator; raises the lever 1. the stop plunger-9 will be forced to,,the 'leftandt'he opemngof the port 25 will be reduced, hence, the more the lever -171s raised the more the )ort 25 will be closed, and the slower the velocity of the,

to be absorbed by the inertia of the tool.

The mon'ientun'i on the forward stroke does not, jar the tool because itis all expended upon the shank 13 of the working tool. To reduce the jarring of the hammer to a minimum, it is necessary to reduce the velocity of the plunger at on the backward stroke as much as permissible. To make the blow of the plunger 1 upon the shank 3 as e'l'l'ective as possible, it is necessary to let the compressed air have free access to the cylinder of the down stroke. or fOIH'tU'Cl stroke, and

to accomplish this, it is necessary that the valve opens the port 25 as wide as practicableto allow the requiredamount of air to pass into the cylinder. It the movennnt ot the value 5 were controlled entirely by the position of the plunger 10, it is evident that the rapidity of the strokes would vary with the forceeot' the blows struck by the pltuigcr 4', both increasing and decreasing together. By providingthe-stop plunger l), the rapidity and-the force Ofliljttf? blows can be varied independently; thus it it is desired to strike with the maximum force. but with a long interval between the blows, the result can be accomplished Lrv depressing the lever 15 to the lowestpositron, which will produce the maximum blow, and by drawing the lever 17, upward which will reduce the rapidity of the strokes.

.Tn reduce the vibration of the tool as lIltlClLZh-S possible, the extent to which the port- 21") is openedwhen the parts are in the positionshown in the drawing, that is when the ports and 25 are connected, is determined experimentally, the opening being gradually increascd-uiitil the jarring be comes all that is considered admissible. For

I any rapidity of strokes below this limit-,the

vibration will be decreased. If it isdesired to arrange the tool so that the movement ot the plunger 4 may be actually stopped by moving the lever 17, the levers 17 and 18 are arranged in such a manner that they can move the plunger 9 so far to the leftthat the valvewill not open the port when moved 'to the right; hence, the air. in the upper end I of the cylinder cannot pass to the lower end.

1 If it is not desired to have the tool operate in this way, but merely to have the move ment of the lever 17 acting to reduce the rapidity of the strokes, a suitable stop is provided to limit the movement of lever 18.

The simplest way to provide such a stop is to make the distance between the upper end of the lever 18, and the handle 1 such that when the lever strikes the handle, the rapidity of the strokes is reduced to minimum.

From the foregoing explanations, t Wlll be seen that till my improved hammer, it

is possible ,to strike the hardest blow with When the levers 17, and 18, are provided, I

the operator can vary the rapidity of the strokes at will; but in many cases this is not necessary, itv being sullicient'to be able to set the tool to operate at a given velocity. In

such case, the levers 17, 18, are discarded and the stop plunger 9 and the head 8 are made as shown 'in Fi 10 so that the plunger may be set in any desired position. To hold it securely in this position, a check nut '61 is provided.

The office of the port 44 to provide an outlet for the-air from the space 52 under the plunger. when the latter on the forward stroke has moved far enough .tomake the head 50 cover the port 53. After this port is covered the air escapes through the port 30 and the valve chamber to the exhaust port .44. I

It will be noticed particularly that the valve 5 plays the double par-t ot an actuating valve and a throttle valve, but it is to be understood that my invention is notrestricted is used.

It will be easily understood that the the head 7 in the position in which it is shown in Fig. 1, or it could. be made integral withthe head, and the compressed air could be admitted to the tool through any of the various forms of throttle valves commonly used, such valve being operated by the lever 16, or in any-other desired manner. Thus a simple stopcock in the inlet 1-1 could be made to answer the purpose of a throttle.

In order that a pneumatic hammer of this type may deliver the hardest blow possible at the available pressure of the compressed air,'it is necessary that the construction be such thatthe loss of pressure between the supply pipe and the cylinder be reduced to minimum. As the movement of the plunger st on the forward stroke is resisted only by the small frictional resistance and a very slight back pressure, it will accelerate its 've-. locity very rapidly, and thus reduce'the pressure materially if the ports connecting the valve withthe cylinder are long. In

through the valve is reduced, to give ighter to this arrangement, because the valve 5 in 'plunger 10 could be pern'ianently secured to blows; If the valve is placed as close to the cylinder as possible, as in Fig. 1, the presair may be throttlcd, because the clearance space Within the valve chamber and the ports connecting with the cylinder, is so small that it can be filled without making a material reduction in the pressure in the port'26, and this pressure is the same as that at the inlet 14, owing to the large size of the connecting passages 32, 33 and 27.

Having described my invention, what I- claim as new is:

l. A pneumatic tool having an actuatingvalve operated by, the compressed air in a continuously automatic manner and means.

movable independently of the valve controlling said valve whereby it is adapted to perform the function of athrottlihg valve. 2. In a pneumatic tool, the combination with the reciprocating plunger, of an actuat ing valve operated by the compressed air in' a ,continuously automatic manner, and arranged to vary the velocity of the plun er during the return stroke, and means whereby the valve is adapted to perform the function of a. throttling valve.

3. In a pneumatic tool, the combination 1 with the reciprocating plunger, of an actuattling valve.

ing valve operated by the compressed air in' a continuously automatic manner and adapt- .ed to control the velocity of the plunger on the return stroke, resiliently mounted means for varying the stroke of said valve while in action, and means whereby the valve is adapted to perform the function t. In a pneumatic hammer, the combination with the working cyllnder, of an actuatmg valve arranged to admit compressed air to the upper end of the cylinder and to permit the transfer of such air from the upper to the lower end of the cylinder, and means whereby the valve is adapted to per form the function of a throttling valve.

5. In a pneumatic hammer, the combination with the Working cylinder, ofa combined throttle and actuating valve arranged to admit compressed. air to the upper end of thecylinder and to transfer such air from the upper to the lower end of the cylinder,

and the valve controlling the rateof flow during the transfer, and resiliently-mounted means movable relatively to the valve and under the control of the operator to vary the the hammer. 4

.6. In a pneumatic hammer having a reciprocating operating valve actuated by, the compressed air, means movable relatively to the valve for controlling the travel of the 4 action of the valve during the operation of 'valve in such manner as to permit the thro n 'of a throt;

sure acting on the plunger 5, at the beginning of the stroke, will .be nearly the full pressure, no matter how much the supply of.

. tion of. the

establishing communication to be modified at will during the operation of the hammer.

7. A portable pneumatic hammer provided with an actuating valve placed directly above; the cylinder end, said valve;

being reciprocated continuously by the pressure fluid while the tool is in action; and means to enable the valve to act as a throttle when the tool is not in action.

8. In a pneumatic hammer having a re ciprocating operating valve actuated by the compressed air, means actuated independ ently of the valve for controlling the movement of the valve in either direction independently while the hammer is at work.

9.111 a portable pneumatic hammer, a

working cylinder and striking plunger; an

operating valve placed directly above the.

end of the cylinder, said valve being adapt-- ed to reciprocate continuously under the ac- -working cylinder and striking plunger; an

operating valve located directly above the cylinder end, said valve being reciprocated continuously by the pressure fluid while the ressure fluid; means operable tool is in action, means acting independently. I

of the valve for instantly varying the throw of the valve in either direction while the tool is in action, said means enabling the valve to act as a throttle when the tool is not in action. I

12f In a pneumatic hamm'er, the combination with the working cylinder, of a reciprocating. operating valve actuated by' thecompressed air and adapted to control the flow of airfrom one end of the cylinder to theother, and means acting independently. of the valve for 'varying the. movement of the valve during the movement thereof.

13. A pneumatic'hammer, having a working cylinder, an automatically actuated valv directly above the cylinder; and means actuated independently of the valve, here. by said valve is adapted to perform the functions of a throttling valve. 14. In a compressed air actuated der, the plunger, and passages communicating with the upper end of the cylinder and betweenends of the cylinder; and means emulated inhammer, the combmation wlth a working cylintion. one of said stops being further adapted to start and stop the hai'nmer.

16. I11 a pneumatic hammer, having acontinumisly automatic actuating valve, stops adapted to slide axially in'the direction of movement, of the valve, and means whereby the stops are held in any desired,

position subject to the will of the operator.

l7. In'a pneumatic hammer having a con- 'tinuonslyautomatic actuating valve, stops adapted to slide axially in the direction of.

movement of the valve, means whereby the stops are heldln any desired position so as to l1m1t the throw of the valve in either direction, and means for adjusting the position of one of the stops.

18. In a pneumatic hammer having a continuously automatic actuating valve, stops adapted to slide -resiliently in the direction of movement of the *alve, means whereby the stops are heldin any desired position so as to limit the throw of the valve in either lirection, and means for varying the positions of said stops independently.

19. In a pneumatic hammer the comblnation of a working cylinder, a valve chamher to which the compressed air has access,-

a continuously acting pressure-actuated valve within said valve chamber, controlling the admission of pressure medium to the [Working cylinder, and means actuated at will independently .of the valve defining the movement of said valve and causing the valve to throttle the flow of pressure medium. v

20. A pneumatic hammer provided with two actuating levers arranged tobe operated by the fingers of the operator, one of said levers acting to control the force of. .the blows struck by the hammer, the other of said levers acting 'to control the rapidity of the blows, and stops moved by said levers,

arranged to slide freely in the pathof the actuating valve to limit the throw of the valve in either direction.

21. In a portable pneumatic hammer having an operating'valve that is reeiprocated by the pressure fluid; means for varying the throw of the valve in either direction, said means being constructed and arranged to be operated by the fingers on that hand of the operator that'grasps the handle of the tool,

and comprising means adapting the throw of the valve in either direction to be instantaneously varied independently of the throw in the other direction and by a movement of the operators fingers.

22. A portable pneumatic hammer provided with but a single valve, and means actuated independently of the valve for holding said valve in the closed position to stop the hammer; said valve being constructed; and arranged to reciprocate continuously when released and acted upon by the pressure fluid.

23. A portable pneumatic hammer having a single valve, stops, between which, the valve when released, reciprocates continuously under the influence of the pressure fluid; and means for moving one of said stops to hold the valve against movement under the pressure fluid and thereby arrest the reciprocation of the valve, and stop the action of the hammer.

24. Ina portable pneumatic hammer having a plunger, ports controlling the plunger, a combined operating and throttle valve, controlling said ports, stops, between which the valve reciprocates, valv controlling ports opened and closed by the 'movement of the valve, whereby it recipro'cates continuously under the pressure fluid, ene of said stops being movable to arrest the valve short whereby the valve is held stationary-by the pressure fluid andthe hammer isstoppe and the other stop being mo able to arrest the immanent of the valve in the other direction, in position in which it partly opens ports, whereby the the plunger controlling force of the blow is modified.

25. In a portable pneumatic hammer a combined operating and throttle Valve adapted to be reciprocated continuously between movable stops by the pressiire fluid and means mounted in the handle of the tool by means of which the position of either one of the mo able stops may be instantly changed during the action of the tool in I such manner as to vary the velocity of-the striking plunger.'

26. In a portable pneumatic-hammer an operating valve adapted to be reciprocated between two movable stops by the pressure fluid; means actuated independently of said stops for instantly changing the position of each one of thestops; said means being actuated by the'hand of the operator.

o! its port opening. position in one direction,

27. In a pneumatic hammer a combinedthrottle and automatic operating valve adapted to be reciprocated continuously by the pressure fluid during the action of the tool; said valve being positioned directly above the cylinder in such manner as to reduce to a minimum, the length of the ports from the valve to the cylinder. 28. A pneumatic hammer having valve Fontrolling ports, a combined automatic op erating and throttle valve actuated by the pressure which itcpntrols, supplied through said ports and constructed substantially as described to open the valve controlling ports at the ends of its strokes, and means arrest- 1 ing the valve before it opens the port at one end-0f its stroke whereby it is held by the pressure medium and the action of the hammer is stopped. Y-

29. In a portable pneumatic hammer, a

-working cylinder and striking plunger; an

automatic operating valve reciprocated by the pressure fluid, sa d valve being con- Strdcted and arranged to vary the rate of fiow of'the'pressurefluid into the cylinder jand also to Vary the rate of transfer of the fiuid'froin one end of the cylinder to the other; and means actuated independently of the valve for enabling the valve to effect both variationsindependently of each other,

.saidmeans also enabling the valve to act as v a throttle when the tool is not in action.

30. In a portable pneumatic hammer a working cylinder and striking plunger; an

-- automatic operating valve located directly above the'end of the cylinder and in a position to admit. pressure fluid to the upper end thereof and to transfer it to the lower end thereof; and means actuated by pressure and pendcntly of the valve, .whereby the throw of the valve can be instantly changed at the will of the operator While the tool is in action. i

In a portable pneumatic hammer having an voperating valve that is reciprocated by the pressure fluid, means controlled by the fingers of the hand that grasps the handle' of the toolwhereby the throw of the valve can bechanged instantly and independently in either direction while the tool is in .use.

'lhe foregoings ecification signed at J ersey City Hudson y,,this 16th day of Feb ru-ary 1906; v

WILLIAM BAXT'ER, JR. In presence ofv two witnesses- RUTHERFORD LAVE, THOMAS P. JOHNs'roN.

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