Tools – Wrench – screwdriver – or driver therefor – Handle clutched to head
Reexamination Certificate
2000-03-13
2001-07-24
Hail, III, Joseph J. (Department: 3723)
Tools
Wrench, screwdriver, or driver therefor
Handle clutched to head
C081S058000
Reexamination Certificate
active
06263767
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a pawl for a ratchet-type spanner to provide reliable ratcheting.
2. Description of the Related Art
Spanners are the best choice for working in a tight area, yet the backlash is too large. Ratchet-type spanners have been proposed to solve this problem, and
FIGS. 7 through 9
of the drawings illustrate a typical design. As illustrated in
FIG. 7
, the ratchet-type spanner includes a handle
1
′ with a box end
11
′ for rotatably receiving a ratchet gear
2
′ that is mounted between a ring-like cover plate
6
′ and a ledge
8
′ and retained in place by a C-clip
7
′. A side of the box end
11
′ is drilled to form a hole
12
′ that extends along an axis at an angle of &thgr; (12°~18°) with a horizontal axis of the box end
11
′. A pawl
3
′ is mounted in the hole
12
′ and includes ratchet teeth
31
′ formed on a side thereof for releasably engaging with teeth
21
′ of the ratchet gear
2
′ and a includes compartment
32
′ defined in the other side thereof. A spring
4
′ is mounted in the compartment
32
′ for biasing the pawl
3
′ to engage with the teeth
21
′. A threaded plug
5
′ is mounted in the hole
12
′ and engaged with an inner threading
121
′ of the hole
12
′. The plug
5
′ includes an inner side
51
′ for retaining the spring
4
′ and the pawl
3
′ in place and includes an outer side with a hexagonal recess
52
′.
Nevertheless, the position of the plug
5
′ affects the function of the pawl
3
′. Namely, the pawl
3
′ cannot be effectively engaged with the ratchet gear
2
′ for ratcheting if the plug
5
′ is too far from the ratchet gear
2
′. On the other hand, the pawl
3
′ will be stuck with the ratchet gear
2
′ if the plug
5
′ is too close to the ratchet gear
2
′. Optimal positioning of the plug
5
′ is time-consuming and very difficult to achieve even by a skilled worker. Assembly cost is accordingly increased. In addition, the threading engagement between the plug
5
′ and the hole
12
′ tends to wear after a term of use such that the user often has to bond the plug by adhesive or glue. Use of the spanner becomes more inconvenient. In addition, assembly of the spanner is complicated and expensive, as the cover
6
′ and C-clip
7
′ are required. Furthermore, formation of the ledge
8
′ requires expensive and accurate computer-numeric-control (CNC), which further results in an increase in the cost.
The present invention is intended to provide a pawl for a ratchet-type spanner that mitigates and/or obviates the above problems.
SUMMARY OF THE INVENTION
In accordance with a first aspect of the invention, a ratchet-type spanner comprises:
a handle;
a box end extended from the handle and having a hole, a slant hole being defined in a web between the handle and the box end and communicated with the hole of the box end;
a ratchet gear including an inner periphery adapted to drive a fastener and an outer periphery, the outer periphery of the ratchet gear including a plurality of first teeth, the ratchet gear being rotatably mounted in the hole of the box end;
a pawl mounted in the slant hole and including a first end with a plurality of second teeth for releasably engaging with the first teeth of the ratchet gear, the pawl further including a second end;
a plug securely mounted in the slant hole by force-fitting engagement with an inner periphery defining the slant hole; and
an elastic member mounted in the slant hole and having a first end attached to the second end of the pawl and a second end attached to the plug for biasing the second teeth of the pawl to engage with the first teeth of the ratchet gear.
The first end of the pawl includes a beveled face that faces the inner periphery of the slant hole. The web includes an inclined indication area for indicating ratcheting direction of the ratchet-type spanner by an inclination direction of the inclined indication area. The plug includes at least one knurl formed on an outer periphery thereof, the knurl being in force-fitting engagement with the inner periphery defining the slant hole. An inner periphery defining the hole of the box end includes a first annular groove. The outer periphery of the ratchet gear includes a second annular groove facing the first annular groove. A C-clip is received in the first annular groove and the second annular groove for rotatably retaining the ratchet gear in the hole of the box end.
In accordance with a second aspect of the invention, a ratchet-type spanner comprises:
a handle;
a box end extended from the handle and having a hole, a slant hole being defined in a web between the handle and the box end and communicated with the hole of the box end, the web including an inclined indication area for indicating ratcheting direction of the ratchet-type spanner by an inclination direction of the inclined indication area;
a ratchet gear including an inner periphery adapted to drive a fastener and an outer periphery, the outer periphery of the ratchet gear including a plurality of first teeth, the ratchet gear being rotatably mounted in the hole of the box end;
a pawl mounted in the slant hole and including a first end with a plurality of second teeth for releasably engaging with the first teeth of the ratchet gear, the pawl further including a second end;
a plug securely mounted in the slant hole; and
an elastic member mounted in the slant hole and having a first end attached to the second end of the pawl and a second end attached to the plug for biasing the second teeth of the pawl to engage with the first teeth of the ratchet gear.
In accordance with a third aspect of the invention, a ratchet-type spanner comprises:
a handle;
a box end extended from the handle and having a hole, a slant hole being defined in a web between the handle and the box end and communicated with the hole of the box end;
a ratchet gear including an inner periphery adapted to drive a fastener and an outer periphery, the outer periphery of the ratchet gear including a plurality of first teeth, the ratchet gear being rotatably mounted in the hole of the box end;
a pawl mounted in the slant hole and including a first end with a plurality of second teeth for releasably engaging with the first teeth of the ratchet gear, the pawl further including a second end;
a plug securely mounted in the slant hole; and
an elastic member mounted in the slant hole and having a first end attached to the second end of the pawl and a second end attached to the plug for biasing the second teeth of the pawl to engage with the first teeth of the ratchet gear;
the first end of the pawl further including a beveled face that faces the inner periphery of the slant hole and the pawl bears against the inner periphery of the slant hole at a point, whereby when the ratchet-type spanner is turned, the beveled face of the pawl is capable of pivoting about the point and thus moving toward the inner periphery of the slant hole, thereby assuring reliable engagement between the first teeth of the ratchet gear and the second teeth of the pawl.
In accordance with a fourth aspect of the invention, a ratchet-type spanner comprises:
a handle;
a box end extended from the handle and having a hole, an inner periphery defining the hole of the box end including a first annular groove, a slant hole being defined in a web between the handle and the box end and communicated with the hole of the box end;
a ratchet gear including an inner periphery adapted to drive a fastener and an outer periphery, the outer periphery of the ratchet gear including a plurality of first teeth, the ratchet gear being rotatably mounted in the hole of the box end, the outer periphery of the ratchet gear further including a second annular groove facing the first annular groove;
a C-clip received in the first annular groove and the second annul
Hail III Joseph J.
Hi-Five Products Developing Co., Ltd.
Kamrath Alan
Rider Bennett Egan & Arundel LLP
Thomas David B.
LandOfFree
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