US3167135A

US3167135A - Anvil impact tool

Info

Publication number: US3167135A
Application number: US152850A
Authority: US
Inventors: Wilmer Richard Keith
Original assignee: Ingersoll Rand Co
Current assignee: Ingersoll Rand Co
Priority date: 1961-11-16
Filing date: 1961-11-16
Publication date: 1965-01-26
Anticipated expiration: 1982-01-26

Description

Jan. 26, 1965 R. K. WILMER ANVIL IMPACT TOOL.

I 3 Sheets-Sheet 1 Original Filed Aug. 25, 1960 INVENTOR RICHARD K. W/L

mifg mm m HIS AGENT Jan. 26, 1965 R. K. WILMER 3,167,135

ANVIL IMPACT TOOL Original Filed Aug. 25. 1960 3 Sheets-Sheet 2 FIG. 3A

INVE NTOR RICHARD K WIL MEI? HIS AGENT Jan. 26, 1965 R. K. WILMER 3,167,135

.ANVIL IMPACT TOOL Original Filed Aug. 25. 1960 5 Sheets-Sheet 3 INVENTOIR RICHARD K ML 5 CQWQQQ wa HIS AGENT United States Patent Ofitice 3,167,135 Patented Jan. 26, .1965

This invention relates to tools and more specifically to an impact tool having an axially movable anvil, such as a nail driver.

This application is a continuation of my copending application, Serial No. 51,998, filed August 25, 1960, now abandoned, and assigned to the same assignee as the present application.

At the present time, a conventional nail driver normally has a spring biased sleeve to receive the head of a nail which is contacted by a resiliently mounted anvil. A reciprocal piston repeatedly strikes the anvil to drive the nail. When the nail head approaches the workpiece, the sleeve yields against the force of the spring so that the nail can be driven flush with the outer surface of such workpiece. With this type of nail driver, it is diflicult to start driving a nail because the operator has to meter controlling pressure fluid for the. impact force of the tool by progressively displacing a tool trigger to start with a small amount of power and to progressively increase such power as the nail is driven. during the remainder of the driving operation because the operator has to move the tool forward with the nail as it is being driven. In addition, when a coil spring is used to bias the sleeve, inertia tends to break the first of the coils and the rear end of the sleeve may then impact against a shoulder on the anvil and cause breakage.

A nail driver constructed according to this invention is comprised of a barrel with a handle secured thereto. A valve is secured in the rear end of the barrel that Thereafter, it is diflicult to guide the nail is disposed in a blind bore of the handle which sur- Further, in accordance with the present invention, the

tool remains stationary during the entire nail driving operation as distinguished from the aforementioned conventional nail driver in which the tool fol-lows the nail 7 towards the workpiece. As will be seen, a sleeve is fixed to the end of the barrel to receive a nail to be driven and locks a spring in the end of the barrel bore to engage a head on the anvil to limit its movement when the nail is fully driven and to act as a buffer. The nail is placed against the workpiece and into a nosepiece or sleeve that is also placed against the workpiece, thus, the length of the nail limits the forward position of the anvil. At the start of the driving operation, the limited piston stroke is relatively short, and therefore, the anvil is struck lightly asis desirable to start the nail and which approximates the use of a hand wielded hammer. However, as the nail is driven, the piston stroke progressively increases to progressively increase the impact force on the anvil.

An object of this invention is to provide an impact tool having a progressively increasing force output that may be usedby an unskilled operator.

Another object of this invention is to provide an impact tool having a progressively increasing force output and is maintained in a fixed position during each complete driving operation. t

Another object of the invention is to provide an impact tool having an anvil that is repeatedly struck with progressively increasing force.

Another object of the invention is to provide an impact tool which is inoperative or fully operative, and has an anvil that is repeatedly struck with progressively increasing force by a reciprocating piston when operating.

Another object of the invention is to provide an impact tool which is inoperative or fully operative, and has an anvil that is repeatedly struck with progressively increasing force by a reciprocating piston when operating, and includes a valve having a hollow valve member that automatically controls the flow path of the pressure fluid which drives the piston; the hollow valve member providing a path by its bore which forms a portion of the normal path of reciprocation of the piston.

This invention contemplates an impact tool that is held stationary relative to a workpiece during its operating cycle, comprising a barrel, a sleeve connected to the barrel to be placed in contact with the workpiece, an anvil movable in the barrel, apiston reciprocated in the barrel for repeatedly striking the anvil to drive the anvil progressively into the sleeve and toward the workpiece, and valve means in the barrel to. provide pressure fluid for reciprocally moving: the piston.

The foregoing and other objects and advantages of the invention will appear more fully hereinafter from a consideration of the detailed description which follows, taken together with the accompanying drawingswlierein a single ernbodiment of the invention is illustrated by way of example. It is to be expresslyunderstood, however, that the drawings are for illustration purposes only an dare not to be construed as defining the limits of the invention.

FIGURE 1. is an elevational view ofa tool constructed according to the invention with the barrel and forward portion of the handle thereof in vertical section,

FIGURE'Z is an enlarged sectional. view taken on line 2-2 of FIGURE 1, 1

FIGURE 3 is taken on line 3-3-of FIGURE 2 and is a sectional view through the connection of the barrel and handle, and includingthevalve of'the' tool,

FIGURE 3A is a sectional view taken: on line- 3"3 of FIGURE 2 and is; similar toFIGURE .3 Withthe valve in an adjusted position, and

FIGURES 4 and 4A are sectional viewstaken on line 44 of FIGURE 2 and? are similar to FIGURES 3* and 3A.

Referring now to the drawings, and specifically to FIGURE 1, anovel tool in the form of a nail driver is constructed according to the invention andcomprises a barrel 20 threadedly inserted; and locked in a blind bore 1 2 of a handle 10 with a. fitting 14 adapted. to be connected to a source'of pressure fluid (not shown) for operation. A trigger 16 is mounted on thehandle 10 and is manually operable for openingand closinga valve (not shown) in an inlet supply line or. passage 18to controlthe flow of pressurefluidto the blind bore 12. The barrel 20has an axial through here 22 with a rear counterbore 24rd: receiving and liousi'ng a valve 80. Part of the valve 80 extends to and abuts the base of the blind bore 12 in handle 10, and with bore 12 forms an annular pressure fluid cham'lier 58in communication with passage 18. The forward endofthe-bore 22 is counterbored at 26 for receiving a resilient member-or spring 28 with a centralopening 30 coaxial with bore 221 but of a reduced diameter. The 'spring'28i'sdocked in couiiterbore' i 26 by a nosepiece or sleeve 32 with an axial bore 34 that is coaxial with bore 22 and of substantially the same diameter as the central opening 30 of spring 28. The bore 34 has an undercut for permitting slight axial movement of the inner portion of spring 28. When the tool is *to be used, nosepiece 32 is placed against the work with a nail to be driven disposed in bore 34.

The barrel 20 has three

axial bores

36, 40 and 44, angularly spaced from one another and disposed around bore 22, that extend forwardly from the base of counterbore 24. A port 38 connects passage 36 to the front portion of bore 22 of the barrel 28 while passage 44 is connected to the rear portion of bore 22 by axially

spaced ports

46 and 48. Exhaust passage 40 has an exhaust port 42, extending through the wall of barrel 20, that is covered by a perforated annular skint 54 also covering the connection between the handle 10 and barrel 20.

An anvil 50, with an enlarged head 52, is supported in opening 30 of spring 28 and is axially movable in bore 22. A piston 54 is reciprocally driven by the pressure fluid to repeatedly strike anvil t driving it forwardly into bore 34 to drive a nail therein into a workpiece. When piston 54 is driven backwardly into bore 62 of a valve member 60 of valve 80, member 64 then shifts to its forward position to connect pressure fluid behind piston 54 for driving it forwardly into contact with anvil head 52 to hammer anvil 50' forwardly. As this is repeated and anvil 50 moves progressively into bore 34, it may be readily visualized that the length of the stroke of piston 54 increases as will its impact force. When the nail is flush with the workpiece, anvil 50 is in its forward position with its head 52 in contact with spring 28. Spring 28 acts as a shock absorber or buffer becauseits inner coil is permitted to flex into the undercut of bore 34.

The valve 80- alternates the flow of pressure fluid between two flow paths to reciprocally drive piston 54, and has a divided body 82 with a bore 84 coaxial with bore 22 of barrel 20. The movable valve member 60 is reciprocally retained in the bore 84 with its bore 62 also coaxial with bore 22. 'There is an annular groove 64 in the outer surface of valve member 60, spaced forwardly from an annular flange 66 having a front face 68 and a rear face 70. Bore 84 has an annular groove 86, for the flange 66, that has a front face 88 and rear face 90 for contacting flange faces 68 and 70, respectively, to limit the axial movement of member 60.

Theportion of bore 84 rearward of member 60 is reduced to approximately the diameter of

bore

22 or 62 and forms a pressure pocket92 in restricted communication with the chamber 48 through a small port 94.

7 Pressure fluid from chamber 58 also enters the bore 62 through a port 96 that is uncovered when member 60 is in its forward position as shown in FIGURES 3A and 4A,

a then flows into bore 62 to drive the piston 54 forwardly plete the exhaust passage.

The axially reciprocal valve member 66 is maintained in its forward position by the force of the pressure fluid in pocket 92. However, as piston 54 passes port 46 or ports 46 then 48, pressure fluid in bore 22 enters passage 44. Passage 44 is connected to the front of annular groove 86 by a passage 106 in valve body 82, and pressure fluid therefrom acting between faces 68 of

flange

66 and 88 of groove 86 kicks member 60 backwardly toward its second position. At this'time, the area in groove 86 between its face 90 and face 70 of flange 66 reduces and exhausts through passage 104.

With valve member 60 in its rearward position, as shown in FIGURES 3 and 4, port 96 is closed and pressure fluid from chamber 58 entering port 26 flows through a passage 108 to annular groove 86 and to bore 84 between grooves 86 and 1%. While pressure fluid from passage 186 merely kicks member 64? back to uncover passage 108 at groove 86, the pressure fluid from passage 168 then drives member 60 to its rearrnost position.

Groove 64 of member 68 now laps passage 108 at bore 84 and annular groove 180, therefore, pressure fluid passes through

passages

98 and 36 to the front end of bore 22 through port 38 to drive piston 54 rearwardly. With valve member 60 in its rearmost position, annular groove 182 is uncovered and the area behind piston 54 exhausts through passages 194 and to exhaust port 42.

As piston 54 being driven rearwardly enters bore 62 of valve member 66, the exhaust path of bore 62 and pocket 92 through annular groove 10?. is closed and the fluid therein is trapped and compressed by piston 54. The compressing fluid in pocket 92 not only acts as a buffer for rearwardly moving the piston 54 but will provide sufficient force against the back surface of member to move it forwardly and return it to its position as shown in FIGURES 3A and 4A. Additionally as piston 54 enters bore 62, it uncovers port 48 or

ports

48 and 46, thus, connecting passage 44 to port 38 by bore 22. Therefore, as member 66 moves forwardly, groove 64 reconnects passage 36 for exhausting, and pressure fluid from the area between faces 68 and 88 of flange 66 and groove 86, respectively, is exhausted.

Therefore, the novel device as described herein, includes a pressure fluid driven motor having valve means to automatically reciprocate the piston thereof for progressively driving an anvil toward a workpiece and into a sleeve that is connected to the end of the motor and isplaced in contact with such workpiece prior to operation of the device. 1

Although but a single embodiment of the invention has been illustrated and described in detail, it is to be expressly understood that the invention is not limited thereto. Various changes may also be made in the design and arrangement of the par s without departing from the spirit and scope of the invention as the same will now beunderstood by those skilled in the art.

I claim: V

1. An impact tool that is held stationary relative to a workpiece during its operating cycle, comprising a barrel, a sleeve connected to the barrel to be placed in contact with the workpiece, an anvil movable in the barrel,

a piston reciprocated in the barrel for repeatedly striking the anvil to drive the anvil progressively into the sleeve and toward the workpiece, and valve means in the barrel to provide pressure fluid for reciprocally moving the piston.

2. An impact tool comprising a barrel, a sleeve connected to the barrel to be placed in contact with a workpiece, a valve disposed in the barrel to receive pressure fluid, a hollow valve member movable in the valve between two positions to provide pressure fluid from the valve for reciprocating a piston, an anvil movable axially in the barrel, and a piston reciprocated in the barrel between a position in the valve member and a position contacting'the anvil to repeatedly strike and drive the anvil progressively into the sleeve. 7

3. An impact tool comprising a barrel, a sleeve 'connected to the barrel and to. be placed in contact with a workpiece, a valve disposed in the barrel to receive pressure fluid, a hollow valve member movable in the valve between two positions to provide pressure fluid from the valve for reciprocating a piston, an anvil having a head and being'movable axially in the barrel, a piston reciprocated in the barrel beteween a position inthe valve member and a position contacting the anvil head to repeatedly strike and drive theanvil progressively into the sleeve, and resilient means disposed between the sleeve and the anvil head to limit the movement of the anvil into the sleeve and to butter the anvil head when the anvil reaches its limit.

4. An impact tool comprising a barrel, a valve disposed in the barrel to receive pressure fluid, a hollow valve member movable in the valve between two positions to provide pressure fluid from the valve for reciprocating a piston, an anvil axially movable in the barrel, and a piston reciprocated in the barrel between a position in the valve member and a position contacting the anvil to drive the anvil progressively away from the valve.

5. A tool comprising a barrel, a hollow valve member reciprocal in the barrel, an anvil movable axially in the barrel and to be driven progressively away from the valve member, a piston movable axially in the barrel and into the hollow valve member, and means for driving the piston out of the hollow valve member into engagement with the anvil with progressively increasing force determined by the relative positions of the anvil to the valve member.

6. A tool comprising a barrel, a valve in the barrel, a hollow valve member reciprocal in the valve, an anvil slidable in the barrel and to be driven progressively away from the valve, a piston reciprocal in the barrel between two positions within the hollow valve member and engaging the anvil, and means when the piston enters the hollow valve member for moving the member to provide pressure fluid for moving the piston into engagement with the anvil with progressively increasing force determined by the relative positions of the anvil to the valve.

7. A tool comprising a barrel, a valve disposed in the barrel, a hollow valve member movable in the valve between two positions, an anvil slidable axially in the barrel, a piston reciprocal in the barrel to repeatedly strike the anvil with progressively increasing force, means for moving the hollow valve member to one of its positions for admitting pressure fluid through the valve and the barrel in front of the piston to move the piston toward the rear end of the barrel and for exhausting the fluid behind the piston to atmosphere as the piston moves toward the rear end of the barrel, and the piston entering the hollow valve member compressing fluid in the valve that acts to move the hollow valve to the other of its positions to provide pressure fluid through the valve to drive the piston out of the hollow valve member to strike the anvil.

8. An impact tool comprising a barrel, a valve disposed in the barrel to receive pressure fluid and having a bore closed at one end to form a pocket, a hollow valve member movable in the valve between two positions to provide pressure fluid from the valve for reciprocating a piston and to the pocket when the piston moves away from the valve, an anvil axially movable in the barrel, and a piston reciprocated in the barrel between a position in the valve member and a position contacting the anvil to drive the anvil progressively away from the valve, the piston trapping and compressing the fluid in the pocket as it moves into the valve member to bufler the piston and to move the valve member for providing pressure fluid to move the piston into contact with the anvil.

9. An impact tool comprising a barrel, a sleeve connected to the barrel to be placed in contact with a workpiece, a valve disposed in the barrel to receive pressure fluid and having a bore closed at one end to form a pocket, a hollow valve member movable in the valve between two positions to provide pressure fluid from the valve for reciprocating a piston and to the pocket when the piston moves away from the valve, an anvil having a head and being movable in the barrel, a piston reciprocated in the barrel between a position in the valve member and a position contact the anvil head to repeatedly strike and drive the anvil progressively into the sleeve, the piston trapping and compressing the fluid in the pocket as it moves into the valve member to butter the piston and to move the valve member for providing pressure fluid to move the piston into contact with the anvil, and resilient means disposed between the sleeve and the anvil head to limit the movement of the anvil into the sleeve and to buffer the anvil head when the anvil reaches,

BROUGHTON G. DURHAM, Primary Examiner. KARL I. ALBRECHT, Examiner.

Claims

1. AN IMPACT TOOL THAT IS HELD STATIONARY RELATIVE TO A WORKPIECE DURING ITS OPERATING CYCLE, COMPRISING A BARREL, A SLEEVE CONNECTED TO THE BARREL TO BE PLACED IN CONTACT WITH THE WORKPIECE, AN ANVIL MOVABLE IN THE BARREL, A PISTON RECIPROCATED IN THE BARREL FOR REPEATEDLY STRIKING THE ANVIL TO DRIVE THE ANVIL PROGRESSIVELY INTO THE SLEEVE