Reversible Impact Wrenches

Abstract

This invention relates to a reversible impact wrench in which the rotation director and exhaust are provided in a single continuous bore which may be machined after casting, thereby reducing the cost thereof, and further which provides a manually regulatable trigger valve which utilizes overlapping bores in a sleeve rotatably mounted in a fixed shell to adjust the amount of air delivered to the rotor.

Description

It is the object of this invention to provide a reversible impact wrench which may be produced at less expense and in which the amount of air delivered to the driving means may be selectively regulated.

With the above and other objects in view, which will become immediately apparent upon reading the specifications, my invention resides in the unique and novel form, arrangement, construction and combination of parts shown in the drawings, explained in the specifications, and claimed in the claims.

IN THE DRAWINGS

FIG. 1 is a side-elevational view of a preferred embodiment of my invention;

FIG. 2 is a sectional view taken along lines 2--2 of FIG. 1 with the rotor removed for clarity;

FIG. 3 is a sectional view taken along lines 3--3 of FIG. 2;

FIG. 4 is a sectional view taken along lines 4--4 of FIG. 3;

FIG. 5 is an enlarged view of the rotation director;

FIG. 6 is a sectional view taken along lines 6--6 of FIG. 5;

FIG. 7 is a sectional view taken along lines 7--7 of FIG. 6;

FIG. 8 is an enlarged fragmentary sectional view of the trigger valve mechanism taken along the same lines as FIG. 3; and

FIG. 9 is an exploded view of the trigger valve mechanism with the shell shown in section for clarity.

CONSTRUCTION

Referring now in more detail and by reference character to the drawings, A designates an impact wrench drive mechanism comprising a handle 10, a trigger valve 12, a rotation director 14, an air attachment plug 16 and a vaned rotor 18 journaled in the handle 10 for powered rotation in either direction. The handle 10 is attached to a conventional drive mechanism and housing 20, shown in phantom only, which conventionally accepts rotational power from the rotor 18 and transfers the power to a tool (not shown).

The handle 10 comprises a solid metallic block 22 which is provided with a first bore 24 threaded for accepting the trigger valve 12, a second precision finished bore 26 which extends through the entire handle 10 for nested disposition of the rotation director 14, a third threaded bore 28 threaded for accepting the hose attachment plug 16, and an enlarged chamber 30 for permitting rotational movement of the rotor 18. A first communication passageway 32 establishes fluid communication between the bore 28 and the bore 24. A second communication passageway 34 establishes fluid communication between the bore 24 and the bore 26. A pair of opposing passageways 36, 38, establish fluid communication between opposing sides of the bore 26 and complementary sides of the chamber 30 through recesses 40, 42, which are respectively located on opposing sides of the chamber 30 as shown. An exhaust passageway 44 establishes communication between the chamber 30 and the forward end of the bore 26. Centrally located at the rear of the chamber 30 is a removable cover 46 in which one end of the rotor 18 is journaled; the other end of the rotor 18 (not shown) is conventionally coupled to the conventional drive mechanism (also not shown) in the housing 20. Since my invention relates exclusively to the means and methods for producing a selectively reversible impact wrench, the other end of the rotor and the drive mechanism have not been shown and are not explained for the purposes of simplification and clarity.

The trigger valve 12 comprises a shell 50, an inner sleeve 52, a plunger 54, and a biasing spring 56. The shell 50 includes a hexagonal end 58, a set of external threads 60, an external annular recess 62, a reamed axially extending inner bore 64 and a pair of diametrally opposed radial bores 66, 68 which provide communication between the inner bore 64 and the annular recess 62. The threads 60 are sized for mating with the threads of the bore 24, the recess 62 is located at the juncture of the bore 24 and the passageway 34, and the bores 66, 68 are located in the approximate center of the recess 62, all as best seen in FIGS. 8 and 9.

The inner sleeve 52 (shown in section in FIG. 9 for purposes of clarity) comprises an elongated cylindrical portion 70 sized for snug-fitting disposition in the inner bore 62, an annular flange 72 located at one end, an annular recess 74 located at the other end, an inner bore 76 which extends axially from front to back, and a pair of diametrally opposed radially extending bores 78, 80, which provide communication between the inner bore 76 and the external portion 70, as shown. The recess 74 is sized for accepting a spring clip 82 which retains the sleeve 52 within the shell 50, and the bores 78, 80, are located for axial registration with the bores 66, 68, when the sleeve 52 is disposed within the shell 50, and an O-ring seat 84 is provided at the inner end of the inner bore 76, all for purposes presently more fully to appear.

The plunger 54 includes a cylindrical stem 86 sized for snug-fitting disposition in the inner bore 76, a centrally located neck 88, an intermediate cylindrical element 90 which is diametrally larger than the neck 88 but diametrally smaller than the stem 86, an end portion 92 which is the same diametral size as the stem 86, and an O-ring seat 94 located between the element 90 and the end 92. On the outer end the plunger is provided with an enlarged button 96.

When the plunger 54 is installed in the inner bore 76, and an O-ring 98 is disposed in the seat 94, the radial projection of the O-ring 98 cooperates with the O-ring seat 84 in the sleeve 52 to provide a fluid seal and to hold the plunger 54 in the sleeve 52 as shown. The biasing spring 56 which is conventionally disposed between the back wall of the bore 24 normally biases the O-ring 98 against the seat 84 to keep the trigger valve 12 normally closed.

The rotation director 14 comprises an elongated shaft 100 which is diametrally sized for snug-fitting disposition within the bore 26 and which is provided with a spring-clip-receiving recess 102, a centrally located neck 104, a centrally located diametral segment 106, and a head 108. An elongated bore 110 extends axially from one end of the shaft 100 inwardly past the neck 104, and a pair of orthogonal bores 112, 114, provide communication between the bore 110 and the periphery of the neck 104. A spring clip 116 in the recess 102 retains the rotation director 14 in the bore 26.

OPERATION

Air is provided to the back of the bore 26 through the attachment plug 16 and the passageway 32. The trigger valve 12 is held in the normally closed position by the biasing spring 56. Depending upon whether clockwise or counterclockwise rotation is desired the head 108 of the rotation director 14 is positioned to the right or to the left respectively. The drawings show the positioning for clockwise rotation with the head 108 to the right, and accordingly that operation will be explained first. With the head 108 to the right, air from the trigger valve 12 will be directed from the bore 26 through the passageway 34, against the segment 106, into the passageway 36 and the recess 40, to the chamber 30 where it impels the rotor 18 in a clockwise (from the operator) direction.

That air is then directed around the rotor and into the bore 26 in the vicinity of the neck 104 via the passageway 44. The air is exhausted out the front of the wrench A through the bores 112, 114, and out the bore 110.

To reverse the direction of the rotor 18, the head 108 is moved 90.degree. to the left, which causes the segment 106 to divert the air into the passageway 38 and the recess 42 and thereafter into the chamber 30 against the other side of the vaned rotor 18. In the reverse direction, air is exhausted in the identical manner through the passageway 44, the bores 112, 115, and the bore 110.

If desired, indicia means (not shown) or stops (not shown) may be provided on the cover 46 to identify optimum position of the head 108 for alternative operation.

The trigger valve 12 provides for air regulation in the air supplied to the chamber 30. It will be noted that the position of the shell 50 remains fixed with respect to the handle 10. It should be noted, however, that the sleeve 52 is rotatable with respect to the shell 50. By rotating the sleeve 52 in the shell 50, the degree of overlap of the bores 66, 68 in the shell 50 and the bores 78, 80 in the sleeve 52 may be selectively varied, and the amount of air which passes from the back of the bore 26 into the chamber 30 when the plunger 54 is urged inwardly may thus be regulated.

It should be understood that changes, alterations and modifications in the form, construction, arrangement, combination of various parts of my invention herein shown may be made and substituted without departing from the nature and principle of my invention.

Claims

Having thus described my invention what I claim and desire to secure by Letters Patent is recited in the specifications, shown in the drawings and claimed in the claims.

1. A reversible pneumatic impact wrench drive device comprising a housing integrally including a rotor chamber and first and second bores in said housing, a trigger valve mounted in said first bore, rotation directing means rotatably mounted in the second bore, a vaned rotor journaled in the chamber, coupling means for supplying air under pressure to the housing, a first passageway between the coupling means and the first bore, a second passageway between the first bore and the second bore, third and fourth passageways in said housing between the second bore and opposing sides of the rotor chamber, a fifth passageway in said housing between the rotor chamber and the second bore, and exhaust means for taking air from the fifth passageway and directing said air out of the housing, said trigger valve being normally closed, said rotation directing means integrally including means for selectively directing air from the second passageway to the third passageway and from the second passageway to the fourth passageway, said rotation directing means also integrally including means for pneumatically isolating the second passageway from the fifth passageway.

2. The device of claim 1 wherein the second bore is a uniform bore which extends completely through the housing, and the rotation directing means comprises a cylindrical member which extends completely through said bore in snug-fitting relationship with respect thereto.

3. The device of claim 2 in which the third and fourth passageways are on opposing sides of the second bore and the cylindrical member, and in which two segments have been cut away from opposing sides of the cylindrical member at the third and fourth passageways to define a diametral baffle which selectively diverts air from the second passageway to either the third or the fourth passageway.

4. The device of claim 3 wherein the fifth passageway is axially displaced from the second, third and fourth passageways in the second bore, and the cylindrical member is provided with a diametrally reduced neck in the vicinity of the fifth passageway for collection of exhaust air in the second bore about the neck.

5. The device of claim 4 wherein the cylindrical member also includes an axially extending escape passageway which extends from one end of the member to the neck for exhausting the air collected about the neck.

6. The device of claim 1 wherein the trigger valve integrally includes means for selectively varying the amount of air passed from the first passageway to the second passageway.

7. The device of claim 1 wherein the trigger valve includes a shell secured to the housing in the first bore, a cylindrical sleeve rotatably mounted in the shell, a plunger slidably mounted in the sleeve and spring biased to the normally closed position, a first radially extending port located in the shell at the junction between the second passageway and the first bore, and a second radially extending port located in the sleeve for selective-overlapping engagement with the first port whereby to regulate selectively the size of the opening between the first bore and the second passageway.

8. The device of claim 7 wherein a diametrally reduced neck is provided in the shell in the vicinity of the first port whereby to provide better air movement from the overlapped first and second ports to the second passageway.