US3757875A

US3757875A - Air hammer and combined support and muffler therefor

Info

Publication number: US3757875A
Application number: US00201933A
Authority: US
Inventors: S Gunning
Original assignee: KENT AIR TOOL Co
Current assignee: KENT AIR TOOL Co
Priority date: 1971-11-24
Filing date: 1971-11-24
Publication date: 1973-09-11
Anticipated expiration: 1990-09-11
Also published as: FR2162977A5; GB1381329A; JPS5315442B2; CA949407A; JPS4863505A

Abstract

A support by which a reciprocating air hammer of the type having an elongated body or barrel is pivotally supported on the bucket supporting boom arm of a conventional power shovel, is modified to enclose the hammer body and to muffle the air percussively discharged from the hammer body.

Description

United States Patent Gunning 1 1 Sept. 11, 1973 AIR HAMMER AND COMBINED SUPPORT 3,667,571 5 1971 Fattelay 181/36 A AND MUFFLER THEREFOR 3,599,756 8/1971 Pickle 2,128,742 8/l938 Fuehrer 173/134 X [75] Inventor: Samuel D. Gunning, Cleveland, Ohio [73] Ass1gnee: Kent All Tool Co., Kent, Oh10 Primary Examiner Emest R Purser [22] Filed: Nov. 24, 1971 Attorney-John Harrow Leonard [21] Appl. No.: 201,933

57 ABSTRACT [52] US. Cl 173/44, 173/46, 173/DlG. 2,

181/36 A A support by which a reciprocatingair hammer of the [51] it. Cl. F01" 7/00, 325d l7/l2 yp having an eongated y or barrel is pivotally [58] Field of Search 173/43, 44, l34139, supported on the bucket Supporting boom arm of a 2 conventiona ower s ove is m i 1e to enc ose t e 173/46 DIG 2 l8l/36A 1p h 1 odf d 1 h hammer body and to muffle the air percussively dis- [56] References C'ted charged from the hammer body.

UNITED STATES PATENTS 12/1965 Price 173 134 X 8 Claims, 7 Drawing Figures PATENTED 11 75

sum

2 or 3 INVENTOR.

SAMUEL D. GU NNING N ATTORNEY.

' SHEEI a era MEQK INVENTOR.

SAMUEL D. GUNN l NG ATTORNEY.

AIR HAMMER AND COMBINED SUPPORT AND MUFFLER THEREFOR BACKGROUND OF INVENTION 1. Field of Invention Tool driving or impacting, pneumatically operating, axially reciprocating device with combined support and exhaust muffler.

2. Description of Prior Art Air hammers of the general type herein described are well known in the art, the one shown for illustration in the present application being that disclosed in my copending application, Ser. No. 10,826, filed Feb. 12, 1970, entitled Air Hammer and issued as United States Letters Pat. No. 3,625,295 on Dec. 7, 1971. As therein more fully disclosed, the hammer comprises an elongated body or barrel which is disposed between and connected at its rear end in fixed relation to a pair of laterally spaced supporting plates. The plates, in turn, are pivotally connected to the bucket supporting arm of a conventional power shovel so that the hammer can be moved bodily with the arm and rocked about a horizontal axis to different operating positions relative to the arm. The same plates are pivotally connected to the piston and cylinder assemblage which is provided for operating the bucket. Thus the air ham'mer can be directed at different angles to the arm, selectively, and held at the selected angle during operation. This hammer, and other hammers of this general type, exhaust the air percussively directly to the atmosphere with the result that the exhaust creates a very loud and ir ritating noise. Mufflers of some types have been used to reduce the noise thus created, but have not proven as satisfactory as desired.

SUMMARY OF INVENTION The present invention is directed to the muffling of the percussively discharged air so as to reduce noise greatly. More specifically it is directed to the use of the therein, part thereof being broken away for elearncss in illustration;

FIG. 3 is a side elevation of the structure illustrate in FIG. 2, part thereof being shown in section;

FIG. 4 is a fragmentary front end elevation of the structure illustrated in FIG. 1;

FIG. 5 is a fragmentary cross sectional view of the structure illustrated in FIGS. I and 2, and is taken on the line 55 thereof;

FIG. 6 is a fragmentary cross sectional view of the structure illustrated in FIGS. 1 and 2 and is taken on the line 66 thereof; and

FIG. 7 is a fragmentary rear end elevation of the structure illustrated in FIGS. 1 and 2.

Referring first'to FIG. 1, the present invention is shown as supported on the bucket supporting arm A of a boom B of a conventional power shovel for rocking to different selected operating positions by a piston and side supportingplates for the hammer'as a structural part of the muffler. This is accomplished by extending the supporting plates to a location near the front of the hammer and securing them thereto near the forward end as well as the rear end, thus greatly increasing the rigidity of the support. The, space between the plates is closed at the top and bottom of the plates to provide an enclosing muffling housing into which the exhaust air is discharged and through which it is constrained to flow in a tortuous baffled path so as to discharge near the rear of the hammer with a greatly reduced percussiveness. v

This is accomplished without adding appreciably to the overall dimensions of the supported hammer, the hammer being, in effect, mounted within the muffler.

Various other objects and advantages of the invention will become apparent from the following description in which reference is made to the drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a perspective view of the combined support and muffler of the present invention, with the. hammer supported thereby and with the muffler, in turn, supported on the bucket supporting arm of a conventional power shovel;

.FIG. 2 is an enlarged top plan view of the combined support and muffler with the air hammer mounted cylinder assemblage C of the power shovel which conventionally is connected to the bucket.

The hammer has a body 1 comprising a barrel 2 which is closed at the front end by a suitable header or block 3 with a tool supporting extension 30, and a cylindrical cover 3b. At the rear end the barrel 2 is closed by a header or block 4. The barrel 2 is secured fixedly between the blocks 3 and 4 by tie rods 5. Air under pressure for operating the hammer is admitted through a suitable hose through the rear block 4. Near its forward end the body 1 has an exhaust port 7 which, in the structure shown, is in the block 3'and opens through the cover 3b and exhausts directly into the atmosphere. A tool 8 is carried by the extension 3a of the body 1 and is operated by the air driven mechanism within the body in the conventional fashion. The interior operating parts of the hammer are fully disclosed in my identified patent and, not being a part of the present invention, are not specifically illustrated herein.

The body 1 is supported between two rigid upright side plates 10. The plates 10 have means for pivotal connection to the arm A for rocking relative thereto about a horizontal pivotal axis and have means for connection to the piston rod of the piston and cylinder assemblage C so that the plates can be rocked as a unit about the horizontal pivotal axis to different positions. The means for connecting the plates to the arm A comprise ,a pair of aligned coaxial bores 11 in the plates and which are adapted to receive a pivot 12 usually provided for pivotally mounting the bucket.1The means for connecting the plates to the assemblage are aligned coaxial bores 13 adapted to be pivotally connectedby a pivot 14 to a multiplying linkage D which is driven by the piston and cylinder assemblage C normally for rocking the bucket about the axis of the pivot 12.

The plates 10 are connected in firm face to face juxtaposition with opposite side faces of the mounting block 4 of the air hammer by suitable tie bolts 16 so as to hold the block, and thereby the hammer body 1 in its entirety, in fixed position relative to the plates 10. The structure thus far described is that of my above identified patent. In accordance with the present invention, the plates 10 are extended forwardly from the block 4 beyond the front block 3 and extension 3a, almost to the forward end of the air hammer body 1, as distinguished from my prior hammer in which the side plates terminated forwardly. at the forward face of the block 4. At the forward ends of the plates 10, rigid clamping blocks 17 are disposed between the plates 10. These blocks have cutout portions which provide wall portions, as indicated at 18, which engage the exterior of the body extension 3a for securing the front end of the body in firm clamped position relative to the plates 10. 'Suitable clamping bolts 19 draw the plates 10 firmly against the blocks 17 and the blocks 17 into firm clamping relation with the extension 3a. Thus the hammer is firmly secured in fixed position relative to the plates 10 at both of its ends to form therewith a rigid unitary structure. Due to the depth of the plates 10 and their extent endwise of the body 1, the structure is highly resistant to bending moments both about and transversely of the axis of the pivot 12. The plates 10 extend from a location above the body 1 to a location therebelow, and the space between the plates is closed at the top and at the bottom, respectively, by rigid covers 20.

Each cover 20 bridges across the entire space between the plates 10 and is secured in fixed position relative to the plates 10 by means of bolts 21 threadably engaged with suitable lugs 22 secured to the inner faces of the plates 10. Each cover 20 has an integral depending flange portion 23 at its forward end. The flange portion 23 extends toward the axis of the body 1 and terminates substantially at a horizontal diametral plane through the axis so as to surround the body with slight radial clearance and substantially close the front end of the resultant housing provided by the side plates land the covers 20. i

In order to provide an effective seal to prevent the escape of the exhaust air from the forward end of the resultant housing, a suitable soft or resilient foamed rubber or elastomeric gasket 24 is provided on the inner face of each depending flange portion 23. The gasket 24 is such as to bridge the clearance space between the inner peripheral edges of the flange portions 23 and the outer peripheral surface of the extension 3a of the body 1. As a result of this seaL'the air exhausted percussively from the port 7 is constrained from passing out of the front of the housing. The vibrations caused by the percussive exhaust are damped and not directly transmitted from the body 1 to the depending flange 23.

At its rear end each cover 20 has a flange portion 26, offset outwardly from its normal plane, which is positioned in outwardly spaced relation from the corresponding top or bottom edge face of the block 4. Suitable spacers 27 are disposed between the flange 26 and the adjacent edge face of the block 4 for assuring the spacing of the flange 26 from the face of the block 4 at all times.

As is illustrated in the drawing, the covers 20 and the side plates are in spaced relation to the peripheral wall of the body 1 from a position forwardly of the exhaust port 7 to a position near the forward face of the block. The flanges 26 are also spaced from the block 4 and define with the top and bottom edge faces of the block 4 air discharge openings 29. The openings 29 are conneted with the space defined by the covers 20 and side walls 10 on the one hand and the peripheral exterior wall of the body 1 on the other, so that the exhaust air percussively issuing from the port 7.is discharged through the housing passage and the openings 29 into the atmosphere at the rear of the body.

It is desirable for muffling purposes that the exhaust air passage within the housing formed by the plates 10 and the covers 20 be a tortuous path having restricted portions along its length so as to dissipate the percussive blast of the exhaust and deliver a more uniform flow of air to the outside atmosphere. For this purpose, baffles 30 are provided within the exhaust air passage in the housing at a location between the exhaust port 7 and the exhaust openings 29. One such baffle 30 is shown for purposes of illustration, and comprises a metal plate 31 having a central passage 32 which accommodates the body 1 of the hammer with slight radial clearance. Secured in overlying relation to one side of the plate 31 is a resilient gasket or sealing pad 33, which may be foamed rubber. The pad 33 has a central opening 34 which is sufficient to bridge the clearance space between the edge wall defining the passage 32' and the exterior peripheral wall of the body 1, thus providing an effective seal therebetween and preventing vibrations of the body 1 from being transmitted to the plate 31. The plate 31 extends entirely across the space between the two side plates 10, but is ofless height than the distance between the inner faces of the covers 20 thereby providing restricted passages 35 past the baffle 30 at its top and bottom. As a result, the air from the exhaust port 7 is discharged into a large exhaust passage in which a large volume of air dampensits immediate percussive shock. The air then flows at a relatively high speed and at a more nearly uniform velocity through the restricted passage 35, which further dampens the percussive effects, and then again expands, thus further reducing the percussive and pulsating effect. Finally the air is discharged at relatively high speed and at a still more nearly uniform flow through the restricted openings 29, being reduced to pulsations which cause much less noise than the staccato bark which would be caused were the air discharged from the port 7 directly into the atmosphere.

For securing the side plates 10 and covers 20 fixedly at positions relative to the midportion of the hammer body and for supporting the. baffle 30, plates 37 are provided. These plates 37 are juxtaposed against the inner faces of the side plates 10 at their outer faces and have concavities 38 at their inner faces, the walls of which firmly embrace the outer peripheral wall of the barrel 2. They may be welded to the barrel, if desired. In the form shown, the plates 37 are held in firm clamping engagement with the barrel 2 and with the side plates 10 by means of suitable tie bolts 39. 1

The baffle 30 is disposed so that the lateral edges of the pad 33 is disposed against the forwardly facing edges of the baffle supporting plates 37. Accordingly, the pad 33 is held firmly in place by compression at its lateral edges between the metal plate 31 and forwardly facing edges of the plates 37.

For holding the plate 31 in proper vertical position, suitable cams 40 are provided on the covers and arranged with the cam surfaces sloping inwardly of the body 1 in a direction toward the front of the body so that, as the covers are drawn firmly in place by the bolts 21, the cams engage the plate 31 of the baffle 30 and center it and urge it firmly against its resilient foam rubber padv 33.

It is apparent that with this arrangement the air percussively discharged from the port 7 is muffled by passing along a tortuous path through an exhaust passage which has first a portion with a very large cross sectional area relative to the area of the port 7, then, where restricted by the baffle 30 part way of the length of the passage, and then final restricting passages 29 as the air is discharged into the atmosphere. The repeated discharge of the exhaust air into a large space, its restricted flow from that space followed by another restriction of flow reduces the sharp percussive blasts of the air to a more uniform pulsating high speed flow so that the noise level is reduced to about half of that usually occurring when the air from the exhaust port 7 is discharged directly into the atmosphere. This level is below that at which the noise is too loud for conversation and is very irritating and painful to the ears. Having thus described my invention, I claim: 1. An air hammer including a rigid body having an exhaust port and adapted to support a tool at one end; a rigid elongated hollow muffler housing enclosing said body from a location near said one end of the body to a location near the other end of the body and secured to the body in fixed position relative thereto, and having a discharge opening spaced from said port; the peripheral wall of said housing being spaced from the body so as to provide an exhaust passage therebetween and affording communication between the opening and the port; means constraining the air discharged from the port to discharge through the opening; first connecting means on and rigid with the housing at said other endof the body and adapted for pivotally connecting the housing to a power driven movable support for rocking of the housing in a fixed path about a predetermined axis extending transversely of the. body and for transmitting heavy working load forces to the housing bythe power driven movable support; second connecting means on the housing at said other end of the body and having a pivotal axis offset transversely from said predetermined axis, and adapted for pivotal connection to a reciprocable power device on the power driven support for rocking the housing about said pivotal axis by heavy working load forces applicable by the device independently of the movement of the movable support, when the housing isconnected to said movable support; and

said housing. being sufficiently rigid and strong to blast of the air discharged from said port before the air reaches said discharge opening. I

3. The structure according to claim 2 wherein said baffle means comprise a sheet of metal extending transversely of, and surrounding, the body at a predetermined location, and blocking the major portion of the cross section of said passage at said location, and having an outer peripheral edge portion spaced from the wall of the housing and providing a passage between said edge portion and said wall.

4. The structure according to claim 1 wherein the housing has side walls which are rigid supporting plates, respectively,-and each of which is connected at its opposite ends to the opposite ends of the body for supporting the body by, and in fixed relation to, the plates;

a movable support is pivotally connected to the plates by said first connecting means;

power driven means are carried by the movable support and are pivotally connected to the plates by said second connecting means; and

said plates are disposed at opposite sides of the body,

respectively, and are capable in and of themselves of transmitting said heavy working load forces directly from said other end of the body to said one end of the body.

5. The structure according to claim 1 wherein the muffler housing includes two strong rigid working load forces transmitting supporting plates disposed at opposite sides of the body, respectively; each plate is rigidly connected to the body near opposite ends of the body, respectively;

said first connecting means are on, and rigid with said plates; and said second connecting means are on and rigid with said plates.

6. The structure according to claim 1 wherein the end of the body opposite from said one end is a block rigidly connected to, and in supporting relation to, the remainder of the body;

the muffler housing includes two rigid, heavy working load force transmitting and supporting plates extending alongside opposite sides of the body from said block toward said one end of the body;

means fixedly secure the plates to the block; and

additional means secure the plates to the body near the said one end.

7. The structure according to claim 1 wherein a power driven movable support is provided;

the muffler housing is rigidly fixedly connected to the body at the opposite ends of the body, respectively, and supports the body;

the first connecting means secures one end of the housing to the movable support and supports the housing for movement with the movable support, and for rocking relative to the movable support about the pivotal axis to different working positions relative to the movable support; whereby the working forces applied by the support to the tool is transmitted through the housing from one end of the body to the other end of the body without subjecting the body between its ends to said forces;

and

power means'are mounted on the movable support and connected to the housing so as to be operable to manipulate the housing and thereby the hammer, to different positions relative to the power driven movable support and against the work with working force.

8. A pneumatic hammer including an elongated rigid body adapted to support a tool at one end;

a'pair of rigid supporting plates arranged alongside opposite sides of the body;

means securing each plate fixedly to the body at the opposite ends of the body, respectively;

a first connecting means on and rigid with the plates at the other end of the body and adapted for pivotally connecting the plates to a movable power driven support for rocking as a unit, with the body, about a predetermined axis extending transversely of the body, and operative to transmit directly to the plates at said other end of the body any heavy working load forces imposed by the movable support;

second means on, and rigid with, the plates at said other end of the body and offset transversely from said predetermined axis and adapted for pivotal connection to a reciprocable power device on said support for rocking the plates and body as a unit about an axis offset from said predetermined axis and operative to transmit heavy working load forces from said reciprocable power device directly to the plates at said other end of the body; and

said plates, when secured to the body, in and of them-

Claims

1. An air hammer including a rigid body having an exhaust port and adapted to support a tool at one end; a rigid elongated hollow muffler housing enclosing said body from a location near said one end of the body to a location near the other end of the body and secured to the body in fixed position relative thereto, and having a discharge opening spaced from said port; the peripheral wall of said housing being spaced from the body so as to provide an exhaust passage therebetween and affording communication between the opening and the port; means constraining the air discharged from the port to discharge through the opening; first connecting means on and rigid with the housing at said other end of the body and adapted for pivotally connecting the housing to a power driven movable support for rocking of the housing in a fixed path aboUt a predetermined axis extending transversely of the body and for transmitting heavy working load forces to the housing by the power driven movable support; second connecting means on the housing at said other end of the body and having a pivotal axis offset transversely from said predetermined axis, and adapted for pivotal connection to a reciprocable power device on the power driven support for rocking the housing about said pivotal axis by heavy working load forces applicable by the device independently of the movement of the movable support, when the housing is connected to said movable support; and said housing being sufficiently rigid and strong to transmit directly from each end of the housing to the other end of the housing both longitudinal and transverse heavy working load forces applied to the housing at the other end of the body through said first and second connecting means and to said one end of the housing through the tool end of the body.

2. The structure according to claim 1, wherein baffle means are provided in the housing between the exhaust port and discharge opening for reducing the percussive blast of the air discharged from said port before the air reaches said discharge opening.

4. The structure according to claim 1 wherein the housing has side walls which are rigid supporting plates, respectively, and each of which is connected at its opposite ends to the opposite ends of the body for supporting the body by, and in fixed relation to, the plates; a movable support is pivotally connected to the plates by said first connecting means; power driven means are carried by the movable support and are pivotally connected to the plates by said second connecting means; and said plates are disposed at opposite sides of the body, respectively, and are capable in and of themselves of transmitting said heavy working load forces directly from said other end of the body to said one end of the body.

5. The structure according to claim 1 wherein the muffler housing includes two strong rigid working load forces transmitting supporting plates disposed at opposite sides of the body, respectively; each plate is rigidly connected to the body near opposite ends of the body, respectively; said first connecting means are on, and rigid with said plates; and said second connecting means are on and rigid with said plates.

6. The structure according to claim 1 wherein the end of the body opposite from said one end is a block rigidly connected to, and in supporting relation to, the remainder of the body; the muffler housing includes two rigid, heavy working load force transmitting and supporting plates extending alongside opposite sides of the body from said block toward said one end of the body; means fixedly secure the plates to the block; and additional means secure the plates to the body near the said one end.

7. The structure according to claim 1 wherein a power driven movable support is provided; the muffler housing is rigidly fixedly connected to the body at the opposite ends of the body, respectively, and supports the body; the first connecting means secures one end of the housing to the movable support and supports the housing for movement with the movable support, and for rocking relative to the movable support about the pivotal axis to different working positions relative to the movable support; whereby the working forces applied by the support to the tool is transmitted through the housing from one end of the body to the other end of the body without subjecting the body between its ends to said forces; anD power means are mounted on the movable support and connected to the housing so as to be operable to manipulate the housing and thereby the hammer, to different positions relative to the power driven movable support and against the work with working force.

8. A pneumatic hammer including an elongated rigid body adapted to support a tool at one end; a pair of rigid supporting plates arranged alongside opposite sides of the body; means securing each plate fixedly to the body at the opposite ends of the body, respectively; a first connecting means on and rigid with the plates at the other end of the body and adapted for pivotally connecting the plates to a movable power driven support for rocking as a unit, with the body, about a predetermined axis extending transversely of the body, and operative to transmit directly to the plates at said other end of the body any heavy working load forces imposed by the movable support; second means on, and rigid with, the plates at said other end of the body and offset transversely from said predetermined axis and adapted for pivotal connection to a reciprocable power device on said support for rocking the plates and body as a unit about an axis offset from said predetermined axis and operative to transmit heavy working load forces from said reciprocable power device directly to the plates at said other end of the body; and said plates, when secured to the body, in and of themselves, being sufficiently rigid and strong to transmit directly from each end of the plates to the other end of the plates, both longitudinal and transverse heavy working load forces applied to the plates at said other end through the first and second connecting means, and to said one end of the plates through said tool end of the body.