GB2410914A

GB2410914A - Chuck

Info

Publication number: GB2410914A
Application number: GB0403312A
Authority: GB
Inventors: Hing Sun Li
Original assignee: Black and Decker Inc
Current assignee: Black and Decker Inc
Priority date: 2004-02-14
Filing date: 2004-02-14
Publication date: 2005-08-17
Anticipated expiration: 2024-02-14
Also published as: GB2410914B; GB0403312D0

Abstract

A chuck 1 for use with a rotary power tool is described. The chuck 1 comprises a metallic body member 2 having three angularly spaced bores 3 separated from one another by approximately 120{. Three jaw members 4 are adapted to be inserted into the respective bores 3 such that they can slide back and forth in the bores and project from the front of the body member 2. A split ring 5 fits into an annular indentation 6 formed on the body member 2. When the split ring 5 is in position around body member 2, an inner threaded portion 7 of the split ring 5 engages a corresponding threaded portion 8 formed on the edges of jaw members 4, so that rotation of the split ring around the body member 2 causes displacement of the jaw members 4 in their respective bores 3 to move their distal ends closer together or further apart. A front sleeve 9 is provided with flat portions for engaging flat portions on the split ring 5 so that the split ring 5 rotates with the front sleeve 9. The front sleeve 9 is also provided with resilient clips 16 for holding it in position relative to body portion 2.

Description

CHUCK

The present invention relates to chucks for holding the working member of a rotary tool, and relates particularly, but not exclusively, to keyless chucks for rotary power tools.

Keyless chucks for use with power drills and drivers are well known. Rotation of a chuck sleeve relative to the housing of a tool causes axial displacement of a series of jaw members, the distal ends of which either move closer together to grip a tool bit or further apart to release the tool bit. Chucks of this type are necessary to enable the tool to be used to drive tool bits of different sizes having shanks of different 1 0 diameters.

EP0867249 discloses a keyless chuck in which a split nut is rotatably mounted on a body member. The nut has an inner threaded surface which engages corresponding threaded portions on jaw members slidingly disposed in bores in the body member, and as a result rotation of the nut causes advancement or retraction of the jaw members within their respective bores to move the ends of the jaw members closer together or further apart. An outer sleeve for the user to grip engages the nut by means of several drive ribs formed on the inner surface of the sleeve, the ribs engaging drive slots formed in the nut Consequently, rotation of the outer sleeve relative to the housing of the tool causes concomitant rotation of the nut by virtue of the engagement of the drive ribs with the drive slots, causing advancement or retraction of the jaw members. The components of the chuck are held in position on the tool by means of a nose piece located at the front end of the chuck, the nose piece adapted to press fit onto the front of the chuck in order to hold the outer sleeve in position on the chuck, and in driving engagement with the nut This known chuck suffers from the drawback of having a large number of components of complicated construction and which need to have accurate dimensions to fit together. This significantly adds to the complexity and cost of a tool incorporating the chuck.

P-UK-CS1 1 64 Preferred embodiments of the present invention seek to overcome the above

disadvantages of the prior art.

According to an aspect of the present invention, there is provided a chuck for gripping a working member of a tool, the chuck comprising:- a body portion having a plurality of bores; a plurality of gripping members arranged in respective said bores for gripping a working member of a tool, wherein the gripping members are adapted to slide in a first direction relative to said body portion to move first ends of said gripping members closer together and in a second direction to move said first ends further apart; actuator means rotatably mounted to said body portion and engaging a plurality of said gripping members such that rotation of said actuator means in a first sense relative to said body portion causes movement of said gripping members in said first direction, and rotation of said actuator means in a second sense relative to said body portion causes movement of said gripping members in said second direction; and a first sleeve forming part of a housing of the chuck; wherein said actuator means and said first sleeve comprise at least one respective substantially flat portion such that rotation of said first sleeve relative to a housing of the tool causes rotation of said actuator means relative to said body part.

By providing flattened portions on the inner surface of the first sleeve, and corresponding flattened portions on the outer surface of the actuator means, this provides the advantage of enabling relative rotation of the body portion and actuator means to occur by means of a simpler and less expensive construction. For example, the outer sleeve may be formed from injection moulded plastics material, and the cost of moulds is significantly reduced if it is no longer necessary to mould drive ribs.

According to another aspect of the present invention, there is provided a chuck for gripping a working member of a tool, the chuck comprising:- a body portion having a plurality of bores; a plurality of gripping members arranged in respective said bores for gripping a working member of a tool, wherein the gripping members are adapted to slide in a first direction relative to said body portion to move first ends of said gripping P-UK-CS] 164 members closer together and in a second direction to move said first ends further apart; actuator means rotatably mounted to said body portion and engaging a plurality of said gripping members such that rotation of said actuator means in a first sense relative to said body portion causes movement of said gripping members in said first direction, and rotation of said actuator means in a second sense relative to said body portion causes movement of said gripping members in said second direction; and a first sleeve forming part of a housing of the chuck; wherein said first sleeve is held in position relative to said body portion by means of at least one resilient portion on said first sleeve.

By providing at least one resilient portion on the first sleeve for holding the first sleeve In position relative to the body portion, this provides the advantage of enabling this to occur by means of a simpler construction, which in turn reduces the cost of producing a tool incorporating the chuck.

In a preferred embodiment, the chuck further comprises a bearing assembly acting between said body portion and said first sleeve and including first and second annular washers and a bearing ring having a plurality of bearing members rotatably disposed between said first and second annular washers.

By providing a bearing assembly acting between the body portion and the first sleeve, this provides the advantage of enabling dimensional differences between the body portion and the first sleeve to be taken up, thus further reducing the cost of the chuck by avoiding the necessity of more accurate dimensions.

A plurality of said bearing members may comprise ball bearings.

A plurality of said bearing members may comprise roller beanngs.

At least one resilient portion may engage at least one annular washer This provides the advantage of reducing friction between the first sleeve and the body portion.

P-U K-CS 64 In a preferred embodiment, the actuator means comprises at least one split nut having a respective inner threaded portion adapted to engage a corresponding threaded portion provided on a plurality of said gripping members.

By providing a split nut, this provides the advantage of increasing the ease of assembly of the chuck.

The body portion may have three said bores angularly separated by substantially 120 from one another around a longitudinal axis of said body portion.

The chuck may comprise a second sleeve adapted to slidably engage a rear portion of said first sleeve The chuck may further comprise a nose cap adapted to engage a forward portion of said body member and comprising an aperture for permitting said jaw members to project therethrough.

According to a further aspect of the present invention, there Is provided a rotary tool comprising a housing and a chuck as defined above.

A preferred embodiment of the invention will now be described, by way of example only and not in any limitative sense, with reference to the accompanying drawings in which: Figure 1 is an exploded schematic perspective view of a chuck embodying the present invention; Figure 2 is a partially cut-away side view of the chuck of Figure 1; Figure 3 is a partial side cross-sectional view of the chuck of Figure 1; and Figure 4 is a perspective view of the front sleeve of the chuck of figure 1.

Referring to Figure 1, a chuck shown generally by 1 for use with a rotary power tool (not shown) comprises a metallic body member 2 The metallic body member 2 has three equ-angularly spaced bores 3 separated from one another by approximately 120 around a longitudinal axis of the body member 2. Three jaw P-UK-CS1 64 members 4 are slidably received in the respective bores 3 such that they can slide back and forth in the bores and project from the front of the body member 2, the jaw members 4 being inclined relative to the longitudinal axis of the body member 2 such that sliding movement of the Jaw members 4 causes their distal ends to move closer together (to grip a tool bit) or further apart (to release a tool bit).

A split ring 5 is received in an annular indentation 6 formed on the body member 2, and has an inner threaded portion 7 which engages corresponding threaded portions 8 formed on the outer surface of each Jaw member 4. As a consequence, rotation of the split ring 5 relative to the body member 2 causes axial sliding displacement of the jaw members 4 in their respective bores 3, rotation in a first sense causing advancement of jaw members 4 towards the front of body member 2 to move the distal ends of jaw members 4 closer together, and rotation in the opposite sense causing retraction of jaw members 4 to move their distal ends further apart.

A front sleeve 9, formed from injection-moulded plastics material rotatably fits over the body portion 2 and provides an outer surface for the user to grip. The inner surface of the front sleeve 9 is provided with two flat portions 10, best shown in Figure 4. The outer surface of the split ring 5 is provided with two corresponding flat portions 11 (Figure 3) such that when front sleeve 9 is mounted in position over the body member 2 and split nut 5, the flat portions 10 of the front sleeve 9 engage the flat portions 11 of the split ring 5. As a result, rotation of the front sleeve 9 relative to a housing (not shown) of a tool incorporating the chuck causes rotation of the split ring 5 relative to the body portion 2. This causes concomitant advancement or retraction of jaw members 4 in their respective bores 3 Accordingly, when a tool bit (not shown) is placed in the front of the chuck, in order to grip the tool bit the user rotates front sleeve 9 relative to the tool housing such that jaw members 4 advance through body member 2 and engage the tool bit (not shown) in a tight grip.

A bearing ring 12 comprises a metal support ring with a plurality of ball bearings 13 disposed therein, such that the ball bearings 13 are able to freely rotate.

The bearing ring 12 is sandwiched between front and rear annular washers 14. The front sleeve 9 is provided with a plurality of resilient clips 16 which enable the front P-UK-CS1 164 sleeve to be snap-fitted onto the rear annular washer 14, and a ring member 15 is provided to hold the two halves of split ring 5 in position around annular indentation 6 on body portion 2. In this way, the bearing ring 12 is held in position by means of the front sleeve 9 and variations in dimensions of the components between the front sleeve 9 and body portion 2 are taken up by the resilience of resilient clips 16.

Referring to Figures 2 and 3, when the front sleeve is snapped into position over the body member 2, it can be seen that the bearing ring 12 and washers 14 reduce the friction caused by the front sleeve 9 rotating around body member 2. The front sleeve 9 is held in position over the body member 2 by virtue of the resilient clips 16 engaging the rear annular washer 14 such that the flat portions 10 of the front sleeve 9 engage the corresponding flat portion 11 on the split nut 5 when the front sleeve 9 is rotated relative to the tool housing. In this way, the bearing assembly supports the front sleeve 9 in a relatively low-friction engagement with the front sleeve 2, and no further component is needed to hold the front sleeve 9 in position.

A rear sleeve 17 is rotationally fixed relative to the body member 2, and slidingly engages the front sleeve 9 such that the front sleeve can be rotated relative to the rear sleeve 17. A nose cap 18 is also provided and fixed on the front of body member 2. The nose cap 18 is also rotationally fixed relative to body member 2 such that front sleeve 9 rotates relative to nose cap 18.

The assembly of the chuck will now be described.

To assemble the chuck, the jaw members 4 are placed in their respective bores 3 and the split ring 5 is placed around annular groove 6 such that the threaded inner portion 7 of the split ring engages the outer threaded portion 8 of the jaw members 4.

The bearing assembly is then located over body portion 2 such that ring member 15 abuts a rear face of a flange on body portion 2 and at the same time holds the split ring 5 in position relative to the body portion 2. The body portion 2 Is then inserted into the front sleeve 9 such that the flat portions 10 of the front sleeve 9 engage flat portions 11 of the split ring 5 and the resilient clips 16 of the front sleeve snap over PUK-CS] 64 the rear annular washer 14. Finally, the rear sleeve is placed into position behind front sleeve 9.

It will be appreciated by persons skilled in the art that the above embodiment has been described by way of example only, and not in any limitative sense, and that various alterations and modifications are possible without departure from the scope of the invention as defined by the appended claims. For example, the ball bearings 13 provided in bearing ring 12 may be replaced or accompanied by cylindrical roller bearings.

P-UK-CS1 164

Claims

1. A chuck for gripping a working member of a tool, the chuck comprising: a body portion having a plurality of bores; a plurality of gripping members arranged in respective said bores for gripping a working member of a tool, wherein the gripping members are adapted to slide in a first direction relative to said body portion to move first ends of said gripping members closer together and in a second direction to move said first ends further apart; actuator means rotatably mounted to said body portion and engaging a plurality of said gripping members such that rotation of said actuator means in a first sense relative to said body portion causes movement of said gripping members in said first direction, and rotation of said actuator means In a second sense relative to said body portion causes movement of said gripping members in said second direction; and a first sleeve forming part of a housing of the chuck; wherein said actuator means and said first sleeve comprise at least one respective substantially flat portion such that rotation of said first sleeve relative to a housing of the tool causes rotation of said actuator means relative to said body portion.

2. A chuck for gripping a working member of a tool, the chuck comprising: a body portion having a plurality of bores; a plurality of gripping members arranged in respective said bores for gripping a working member of a tool, wherein the gripping members are adapted to slide in a first direction relative to said body portion to move first ends of said gripping members closer together and in a second direction to move said first ends further apart; actuator means rotatably mounted to said body portion and engaging a plurality of said gripping members such that rotation of said actuator means in a first sense relative to said body portion causes movement of said gripping members in said first direction, and rotation of said actuator means in a second sense relative to said body portion causes movement of said gripping members in said second direction; and a first sleeve forming part of a housing of the chuck; PUK-CS] 164 wherein said first sleeve is held in position relative to said body portion by means of at least one resilient portion on said first sleeve.

3. A chuck according to claim 1 or 2, further comprising a bearing assembly acting between said body portion and said first sleeve and including first and second annular washers and a bearing ring having a plurality of bearing members rotatably disposed between said first and second annular washers.

4. A chuck according to claim 3, wherein a plurality of said bearing members comprise ball bearings.

5. A chuck according to claims 3 or 4, wherein a plurality of said bearing members comprise roller bearings.

6. A chuck according to claim 2 and any one of claims 3 to 5, wherein at least one resilient portion engages at least one annular washer.

7. A chuck according to any one of the preceding claims, wherein the actuator means comprises at least one split nut having a respective inner threaded portion adapted to engage a corresponding threaded portion provided on a plurality of said gripping members.

8. A chuck according to any one of the preceding claims, wherein said body portion has three said bores angularly separated by substantially 120 from one another around a longitudinal axis of said body portion.

9. A chuck according to any one of the preceding claims, further comprising a second sleeve adapted to slidably engage a rear portion of said first sleeve.

10. A chuck according to any one of the preceding claims, further comprising a nose cap adapted to engage a forward portion of said body member, and comprising an aperture for permitting said jaw members to project therethrough.

P-UK-CS

] 1 64 11. A chuck for gripping a working member of a tool, the chuck substantially as hereinbefore described with reference to the accompanying drawings.

12. A rotary tool comprising a housing and a chuck according to any one of the preceding claims.

P-UK-CS] 164