This application claims priority of Taiwanese Utility Model Application No. 100218526, filed on Oct. 3, 2011, the disclosure of which is herein incorporated by reference.
1. Field of the Invention
This invention relates to a hand tool, more particularly to a telescopic hand tool.
2. Description of the Related Art
A conventional torque hand tool, such as a ratchet wrench, generally includes a driving head and a handle connected to the driving head. The handle includes a main shank fixed to the driving head at one end, and an outer sleeve movably sleeved on the main shank to be extendible or retractable relative to the driving head so as to facilitate stowage of the hand tool.
In Taiwanese Utility Model Publication No. M319126, a hand tool with such a telescopic structure has been disclosed, which, as shown in
An object of the present invention is to provide a telescopic hand tool which can be kept steadily in its extended state during operation of the hand tool.
According to this invention, a telescopic hand tool includes an outer sleeve and a main shank. The outer sleeve is elongated along a turning axis to terminate at first and second ends, and having an inner peripheral surface which defines an axial bore. The inner peripheral surface has at least one first arcuate surface region which angularly extends about the turning axis along a circumferential line, and at least one second arcuate surface region which is angularly displaced from the first arcuate surface region in a turning direction about the turning axis, and which is disposed radially and outwardly of the circumferential line. The second arcuate surface region has a low friction area and an increased friction area which is opposite to the low friction area in the turning direction. The main shank has a distal end for connection to a tool head, a proximate end opposite to the distal end along the turning axis, and an outer surrounding surface which extends between the distal and proximate ends. The outer surrounding surface is configured to be inserted into the axial bore so as to be telescopically movable and rotatable relative to the inner peripheral surface along and about the turning axis. A block attachment is disposed on the proximate end and has a rim surface radially confronting the second arcuate surface region. The rim surface is angularly displaceable relative to the second arcuate surface region from a loosened position, where the rim surface is in slidable contact with the low friction area, to a retained position, where the rim surface is in retained engagement with the increased friction area with an increased frictional force so as to guard against rotation of the outer sleeve relative to the main shank.
Other features and advantages of the present invention will become apparent in the following detailed description of the preferred embodiments of the invention, with reference to the accompanying drawings, in which:
Before the present invention is described in greater detail, it should be noted that same reference numerals have been used to denote like elements throughout the specification.
Referring to
The outer sleeve 10 is elongated along a turning axis (L) to terminate at first and second ends 11, 12, and has an inner peripheral surface 14 which defines an axial bore 13. The inner peripheral surface 14 has two first arcuate surface regions 141 which are diametrically opposite to each other relative to the turning axis (L). Each of the first arcuate surface regions 141 angularly extends about the turning axis (L) along a circumferential line (CL). The inner peripheral surface 14 further has two second arcuate surface regions 142 which are diametrically opposite to each other relative to the turning axis (L). Each of the second arcuate surface regions 142 is angularly displaced from the corresponding first arcuate surface region 141 in a turning direction about the turning axis (L), and is disposed radially and outwardly of the circumferential line (CL). Each of the second arcuate surface regions 142 is divided into a low friction area 1421 and an increased friction area 1422 which is forward of the low friction area 1421 in the turning direction.
The main shank 20 has a distal end 21 for connection to a tool head 214, a proximate end 22 opposite to the distal end 21 along the turning axis (L), and an outer surrounding surface 211 extending between the distal and proximate ends 21, 22. The outer surrounding surface 211 is configured to be inserted into the axial bore 13 so as to be telescopically movable and rotatable relative to the inner peripheral surface 14 along and about the turning axis (L).
The block attachment 23 is disposed on the proximate end 22 and has a rim surface 231 radially confronting the second arcuate surface region 142. The rim surface 231 is angularly displaceable relative to the second arcuate surface region 142 from a loosened position, where the rim surface 231 is in slidable contact with the low friction area 1421, to a retained position, where the rim surface 231 is in retained engagement with the increased friction area 1422 with an increased frictional force so as to guard against rotation of the outer sleeve 10 relative to the main shank 20.
In the first preferred embodiment, the block attachment 23 is of a wheel shape and has a dimension smaller than that of the proximate end 22. The block attachment 23 is secured to the proximate end 22 by a bolt member 25 which threadedly engages the proximate end 22 along an offset axis (L1) that is offset from the turning axis (L). After assembly, the radial distance between the offset axis (L1) and the second arcuate surface region 142 is shorter than that between the turning axis (L) and the second arcuate surface region 142 such that an engaging segment 2311 of the rim surface 231 extends radially and outwardly of the outer surrounding surface 211 of the main shank 20. Due to such a configuration of the engaging segment 2311, an interfering engagement, which can provide a much greater frictional force, between the block attachment 23 and a selected one of the second arcuate surface regions 142 can be achieved. Therefore, when the outer sleeve 10 is moved axially along the turning axis (L) to an extended state for applying a desired higher torque, the outer sleeve 10 can be kept in the extended state steadily and assuredly during the torque application without fear that the firm frictional engagement between the outer sleeve 10 and the main shank 20 might fail.
In the first preferred embodiment, the bolt member 25 has a stem 251 that extends along the offset axis (L1), and a bolt head 252 that is configured to be brought by a screw-in action to abut the block attachment 23 against the proximate end 22. The block attachment 23 has a through hole 232 extending along the offset axis (L1) and dimensioned to permit the bolt stem 251 to be fitted therein. Referring to
In accordance with the first preferred embodiment, the block attachment 23 may further include a toothed member 233 disposed on the rim surface 231.
Referring further to
In the second preferred embodiment, the block attachment 23′ is configured to be of generally the same dimension as the proximate end 22′ in cross-section with a slight modification in contour. In this connection, the rim surface 231′ is configured to be generally flush with the outer surrounding surface 211′ of the main shank 20′. Specifically, the rim surface 231′ is configured to have a non-engaging segment 2312′ and an engaging segment 2311′ which is disposed forward of the non-engaging segment 2312′. The engaging segment 2311′ is configured to have a trailing region 2321 and a leading region 2322 which is configured to slope up from the trailing region 2321 to terminate at a front abutment surface 2323 that extends radially so as to be engageable with the barrier wall surface 1423 when the rim surface 231′ is turned to the loosened position.
With reference to
While the present invention has been described in connection with what are considered the most practical and preferred embodiments, it is understood that this invention is not limited to the disclosed embodiments but is intended to cover various arrangements included within the spirit and scope of the broadest interpretations and equivalent arrangements.
Number | Date | Country | Kind |
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100218526 | Oct 2011 | TW | national |