US2158568A - Pneumatic hammer - Google Patents

Description

May 16, 1939. F, H1 BORM PNEUMATIG HAMMER Filed Sept. 16, 1936 Patented May 16, 1939 UNITED STATES PATENT FFE 3 Claims.

This invention relates to pneumatic tools, and more especially to portable, pneumatic hammers for drilling.

An object of my invention is to provide a simple, practical and eiiicient device of the character described.

A further object is 'to lprovide an improved form 'of pneumatic hammer of the portable type for drilling and like operations wherein the hammer is automatically set in operation merely by applying the drill or other tool to the work, no levers, plungers or other device being necessary to be hand voperated in order to start the hammer action.

-Other objects and advantages will appear and be brought out more fully in the following specii'ication, reference being had'to the accompanying drawing wherein:

Fig. 1 is a side View of a tool showing a preferred embodiment of my invention;

Fig. 2 is a view in central section of the tool shown in Fig. l;

Fig. 3 is a cross section view on the line 3-3 of Fig. 2;

Fig. 4 is a similar cross section taken on the line 4 4 of Fig. 2;

Fig. 5 is a similar cross section taken on the line 5-5 of Fig. 2;

Fig. 6 is a similar cross section View taken on the line 6-6 of Fig. 2;

Fig. 7 is a similar cross section view enlarged, taken on the line I--l of Fig. 2;

Fig. 8 is a detailed view showing the tool holding sleeve and its associated member; and

Fig. 9 is an enlarged section, similar to Fig. 2, showing the parts in complete valve opening position.

Referring more particularly to the drawing, I show a pneumatic hammer drill I0, having a hammer cylinder portion II, a valve cylinder portion I2 and a U-shaped handle portion I3. the latter being provided with the usual removable hand piece I4, secured thereto by screws I5 and I6. The hammer cylinder II is provided with a hammer cylinder bore I'I, having a reduced bore portion I8, there being a shoulder I9 at the meeting point of bores I'I and I8. Cylinder `Il is provided with a threaded end portion 20 for reception of a flange plug 2|, by 50 which the `end of the cylinder I'I is closed. A spring bore 22 is formed vadjacent bore I8, and a spring shoulder 23 is provided at the base of bore 22 and adapted to provide a seat for one end of a coiled spring 24. Formed adjacent bore 22 is an enlarged bore 25, there being a shoulder 25a for a purpose to be apparent hereinafter. Bore 25 is provided with an internal threaded end portion 26, for engagement with the reduced threaded end 21 of a locl'ng sleeve 28. Sleeve 28 has a bore 25 and, at the threaded portion 2l, a pair of diametrically opposite slots 30 are formed.

A hammer member 3|, cylindrical in shape, extends through and reciprocates in bores I'I, I8 and 22, and is provided with an enlarged cylindrical portion 32, and a reduced cylindrical portion 33. A shoulder 35. formed on the enlarged portion 32, is complementary to shoulder i9, these shoulders serving to limit the movements of the hammer member 3l in the hammer cylinders. I-Iammer 3l is provided with an internal bore 35 which is closed at one, that is, the outer end, but opening at the other or inner into bore I'I. A small radial drill hole 36 and a pair of larger drill holes 3l are formed in the haL mer 3I, and serve as inlet ports for passage of air as will be more fully apparent hereinafter. A vsimilar' pair of ports 38 are provided for exhausting the air from the hammer cylinder. A plurality of outlet ports 39 are formed in the hammer cylinder II. The hammer 3! has the usual hammer striking face 40.

A valve operating piston 4I is reciprocable in bore 29 of the locking sleeve 23, and has a central bore 42, and at its outer end a recess 43 the base of which forms a shoulder 44. Member 4I has a cylindrical outer surface 45 adapted to fit loosely in bore 29 and has an enlarged cylindrical portion 46 adapted to t in bore 25. Member 4I is further provided with an inner face 4l which face is adapted for engagement with one end of spring 24, the spring normally being under compression between shoulder 23 and face 41 to normally maintain piston liI away from hammer face lill. The enlarged portion of 46 of member 4I has a shoulder 48 for seating against a corresponding shoulder 49 on the threaded end 2l of locking sleeve 28 as will be clear from Fig. 8.

I show a tool such as a star drill 59 having an octagonal shank portion 5| and impact end surface 52, a reduced portion 53 having one or more at faces and a shoulder 54 adjacent to the reduced portion 53.

A locking ball 55 is retained in a bore 55 in member 4I, the bore having a tapering retaining shoulder 5'! and containing a spring 58, the free end of which bears against the inner surfacev or" bore 29 of locking sleeve 28. The ball 55 is adapted to hold the drill 56 in the Valve lll , way l2.

operating piston or member 4l, the ball being maintained by spring 58 against a flat face of the reduced portion 53 and the shoulder 55 of the drill. It will be apparent from this construction that the drill will be maintained in position against turning or dropping out by its own Weight, although the drill may be removed if pulled away by sufiicient force.

A pair of pins 59 are secured in recess 60 in the member 4i in diametrically opposite positions and adapted to reciprocate in slots 3i? of the reduced portion 2 of the locking sleeve 28. A collar 6| is integrally secured to the shank 5l of drill and is adapted to seat against shoulder 44 of recess 43. Cylindrical portion 46 of member 4I has a V-shaped groove 52, one face portion or edge of which forms a conical portion or cam surface 63, in which groove a ball is adapted to rest, ball 64 being further positioned in an aperture 65 formed in a partition wall 6B common to cylinders il and I2.

A valve assembly @l is mounted in valve cylinder i2 having an enlarged valve stem bore iS, the end of' which is closed by threaded plug 3a. Valve cylinder l2 is further provided with a reduced valve stem bore 69, an air chamber 'l and an intake chamber 1l.

Valve assembly 61 is provided with a stem 'i2 adapted to pass through bore 69 and a stem eX- tensicn located in bore 5E, the ree end of stem extension 'i3 having a conical portion or cam surface 'lli engageable with ball Bil. A valve seat 'l5 is formed between chambers 'it and ii and a valve l5 secured to stem 'i2 is adapted to seat on valve seat i5. A spring 'i'i in chamber H bears against an adjustable plug 'i3 and against valve "i6 and normally keeps the valve closed on seat l5. A port or air passage 'i9 interconnects chamber 'it with a chamber i formed between shoulders I and 3s when separated. A small pocket 8l is formed at one end of chamber 1E and is adapted to hold a packing element 82 for sealing bore 69 and stern 'I2 against leakage of air and a collar 83 secures the packing S2 in piace under the action of a spring 84, the ends of which seat against collar S3 and the valve "i5, A threaded aperture 85 forms a passageway to chamber 1l for the intake for air supply conducted from a supply hose 85.

The operation of my invention is as follows. Air under pressure is supplied through hose 86 to air chamber 'EL When the drill or other tool 50 is pressed against the surface of material desired to be drilled, the forward or downward l y movement of hammer lil will cause collar l to engage shoulder 14, resulting in a shifting of member il inwardly, whereupon the cam surface 63 will force ball 64 outwardly against cam surface T4 which will shift the valve assembly El and move valve 1G off its seat '15, thus admitting the compressed air into chamber 'iii and passageway i9 and chamber 83, The pressure in chamber 8G will retract the hammer 3i until ports 36 and 3? are in communication with passage- This will admit the compressed air into bore S5 and bore Il' and the pressure therein will force the hammer against the tool the iace di? striking against the impact end surface of the tool 5%. During the impact movement of the hammer 3l, the exhaust ports 38 will open into bore 22 and outlet ports 39 when the ports sli have reached shoulder E3, thus releasing the shoulder in bore il permitting the hammer 3i to be again retracted under the action of the pressure in the passageway 19 and chamber 80, and

the hammer action will be repeated, it being understood that valve G'i is kept open by the cam surface 53 pressing against ball 64, and it in turn presses against cam surface 'i4 of the valve stem extension i3. Thus the hammer will continue operating as long as tool 5t is kept under pressure against the working material.

While I have illustrated and described the preierred form of construction for carrying my invention into effect, this is capable of variation and modification without departing from the spirit of the invention. I, therefore, do not wish to be limited to the precise details of construction set forth, but desire to avail myself of such variations and modications as come within the scope of the appended claims.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

l. An automatic hammer of the character described comprising a hammer cylinder, a hammer therein adapted to be reciprocated under fluid pressure, a tool holding sleeve in said cylinder, said cylinder having an internal outwardly facing shoulder, a spring between the sleeve and shoulder normally moving the sleeve forward, removable guide means coasting between the sleeve cylinder to prevent turning of the sleeve and permit limited axial movement thereof, a valve cylinder adjacent the hammer cylinder with a passageway therebetween, a valve having a stem in valve cylinder, a member operable in the valve cylinder' adapted to engage the valve for unseating the same and having a cam surface, there being a cam surface around the inner portion of said sleeve formed by a reduced portion thereof, and a ball in said passageway adapted to simultaneously engage said surfaces in opposite directions to open said valve when tool pressure is applied against said sleeve and hold said valve open during the continued application of' pressure.

2. An automatic tool or" the character described comprising, in combination, an operating cylinder, an operating member constructed and arranged to reciprocate in said operating cylinder, valve assembly comprising a valve and a Valve stem adapted to operate and open said valve, a conical portion on said operating member, a cylindricai portion on said operating member adjacent said operating member conical portion, a conical portion on said valve stem, and an intermediate meinber adapted to engage both said conical portions and also said cylindrical portion subsequent to action by said operating member conical portion, whereby said valve is held in open position during Operation of said tool.

3. An automatic tool of the character described comprising, in combination, an operating cylinder, an operating member constructed and arranged to reciprocate in said operating cylinder, a valve assembly comprising a valve and a valve stem adapted to operate and open said Valve, a conical portion on said operating member, a cylindrical portion on said operating member adjacent said operating member conical portion, a conical portion on said valve stem, and an intermediate ball bearing adapted to engage both said conical portions and also said cylindrical portion subsequent to action by said operating member conical portion, whereby said valve is held in open position during operation of said tool and during reciprocation of said operating member.

FERDINAND H. BORM.

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