DE20200363U1 - Unidirectional ratchet wrench - Google Patents

Description

- 1 -UNIDIRECTIONAL RATCHET WRENCH

1. Technical field of the utility model

The present utility model relates to a unidirectional ratchet wrench and in particular to a unidirectional ratchet wrench having excellent torsional resistance.

2. Description of the related art

Referring to Figures 6 and 7, a conventional unidirectional ratchet wrench invented by the applicant of this utility model consists essentially of a wrench body

(60) and an operational order.

In one end of the key body (60) there is a toothed cavity for receiving the insert arrangement

(61). On an inner circumference of the toothed cavity (61) several teeth (62) are formed in the longitudinal direction. Each tooth (62) has an inclined surface

(621) and an upright surface (623), and the inclined surfaces (621) of the teeth (62) are all arranged in the same direction.

The insert assembly consists of an insert wheel (70), two pawls (74) and a split ring (76). An insert (71) is defined in the insert wheel (70) and is adapted to engage a nut or the like connecting member. Two pawl recesses (72) are defined longitudinally in an outer periphery of the insert wheel (70) to internally retain the two pawls (74) and around the outer periphery of the insert wheel

(70) has a groove (73) defined around it to receive the split ring (76). Each pawl (74) is a curved plate with a tapered thickness and a slot (741) defined transversely in the central part of the outer circumference of the pawl (74). A

A locking end (75) is formed on a thin edge of each pawl (74) and a lever end (751) is formed on a thick edge of each pawl (74) opposite the thin edge. When the two pawls (74) are within the pawl recesses (72) of the insert wheel (70), the slots (741) of the pawls are aligned with the groove (73) in the insert wheel (70) and have a special cut or orientation to allow the pawls (74) to swing therein. The split ring (76) holds the pawls elastically in the pawl recesses (74) and compresses the lever end (53) of the pawls (74) so that the locking end (75) of the pawls is pushed outwards. The split ring (76) thereby provides a restoring force on the pawls (74) to bring the pawls (74) into engagement with the teeth (62).

. and then attach the insert wheel (70) to the .key body

(60) to lock. In order to hold the insert assembly in the key body (60), openings of the toothed cavity are also provided on opposite sides

(61) two locking rings (77) open.

When the conventional unidirectional ratchet wrench is operated, the wrench body (60) is rotated so that the locking ends (751) of the pawls (74) engage the straight surfaces (623) of the teeth (62). Then, the insert wheel (70) is twisted by the wrench body (60) and rotates with the latter so that a nut in the insert (71) is also rotated. When the wrench body (60) is rotated in the opposite direction, the locking ends (751) of the pawls (74) move along the inclined surfaces (621) of the teeth (62). Then, the insert wheel (70) does not rotate with the wrench body and the wrench is in an idle state.

However, the traditional unidirectional ratchet wrench has the following disadvantages:

1. The slot (741) in each pawl (74) must be precisely defined in a particular cut and orientation. Otherwise, the pawl (74) cannot be pried open to perfectly engage the locking end (75) with the teeth (61) and the torsional resistance force of the conventional unidirectional ratchet wrench will be low.
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2. The torsional resistance of the key is provided by the locking ends (751) of the pawls (74) and is uneven and insufficient. Therefore, the split ring (74) is easily deformed when the torsional force is slightly excessive.

The main purpose of the present utility model

consists in providing a unidirectional

Ratchet wrench with excellent torsional resistance.

Further benefits and other advantages of the present utility model will become apparent upon studying the detailed description with due reference to the accompanying drawings.

IN THE DRAWINGS SHOW:
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Figure 1 is an exploded perspective view of a unidirectional ratchet wrench according to the present utility model;

Figure 2 is a top functional cross-sectional view of the unidirectional ratchet wrench in Figure 1;

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Figure 3 is a cross-sectional view of the unidirectional

Ratchet wrench taken along line 3-3 in Figure 2 from the side with clamping blocks engaging the toothed cavity;

Figure 4 is a top cross-sectional view of the unidirectional ratchet wrench in idle mode;

Figure 5 is a side cross-sectional view of the unidirectional ratchet wrench taken along line 5-5 in Figure 4 with clamping blocks disengaged from the toothed cavity;

Figure 6 is an exploded perspective view of a conventional unidirectional

ratchet wrench; and

Figure 7 is a top cross-sectional view of the conventional unidirectional ratchet wrench.

0 Referring to Figures 1 and 2, a unidirectional ratchet wrench according to the present utility model comprises a wrench body (10), a ratchet (20), an expansion ring (30) and a plurality of clamping blocks (40).

A toothed cavity (12) is defined in one end of the wrench body (10) for holding the ratchet (20) and other members. A plurality of teeth (13) are formed on the inner circumference of the toothed cavity (12) in the longitudinal direction. Each tooth (13) has an inclined surface (131) and an upright surface (133), and all the inclined surfaces (131) of the teeth (13) are arranged in the same direction.

An insert (21) is defined in the middle of the ratchet (20) and is designed to engage with a nut or a similar connecting part, the insert (21) being defined as a polygon. Around an outer circumference of the ratchet (20) in the transverse direction a

annular recess (22) is defined, and at least two block recesses (23) are evenly and longitudinally defined in the outer circumference of the ratchet (20). In this preferred embodiment, five block recesses (23) are evenly spaced around the ratchet (20).

The expansion ring (30) is mounted in the annular recess (22) and its inner diameter is slightly larger than the outer diameter of a part in the annular recess (22) of the ratchet (20), the expansion ring (30) consisting of an elastic circular strip.

At least two clamping blocks (40) are attached to the expansion ring (30), which correspond to the block-shaped recess (23) in the ratchet (20) and have an outwardly facing toothed surface. Each toothed surface is provided with a plurality of teeth (41) for engaging the toothed cavity (12) in the wrench body (10). In this preferred embodiment, three teeth (41) are formed on each toothed surface of each clamping block (40). Since the expansion ring (30) has a larger diameter than the outer diameter of the ratchet (20), the expansion ring (30) provides a restoring force to push the clamping blocks (40) to engage the teeth (13) in the toothed cavity (12) of the wrench body (10).

In addition, two covers (50) are mounted on the opposite openings of the toothed cavity (12) of the wrench body (10) to enclose the ratchet (20) and other elements in the toothed cavity (12).

Referring to Figures 2 and 3, when the unidirectional ratchet wrench is operated, the wrench body (10) is rotated so that the

Teeth (41) of the clamping blocks (40) engage the straight surfaces (133) of the toothed cavity (12). Then the ratchet (20) is pushed by the wrench body (10) and rotates with the wrench body (10), thereby rotating the nut engaged in the insert (21).

Referring to Figures 4 and 5, when the key body (10) is rotated in the opposite direction, the teeth (41) of the clamping blocks (40) move along the inclined surfaces (131) of the toothed cavity (12) and move out of the toothed cavity

(12). Then the ratchet (20) does not rotate with the wrench body (10) and the unidirectional ratchet wrench is in an idle state.

According to the above description, the unidirectional ratchet wrench has excellent torsional resistance because the clamp blocks (40) for engaging with the toothed cavity are evenly spaced around the ratchet (20). Furthermore, each clamp block (40) is provided with a plurality of teeth (41) for engaging with the wrench body (10), thereby further improving the torsional resistance of the wrench. Moreover, even spacing of the clamp blocks (40) also prevents easy deformation of the expansion ring (30), so that the unidirectional ratchet wrench has a long service life.

Claims (5)

1. Unidirectional ratchet wrench comprising:
a key body ( 10 ) having a toothed cavity ( 12 ) defined in one end, a plurality of teeth ( 13 ) being formed on an inner circumference of the toothed cavity ( 12 ), each tooth ( 13 ) having an inclined surface ( 131 ) and an upright surface ( 133 ), the inclined surfaces ( 131 ) all being arranged in the same direction;
a ratchet ( 20 ) which is unidirectionally and rotatably mounted in the toothed cavity ( 12 ) of the wrench body ( 10 ) and
an insert ( 21 ) defined in the ratchet ( 20 ) and designed to engage with a nut or similar connecting part;
an annular recess ( 22 ) defined transversely around an outer circumference of the ratchet ( 20 ); and
has at least two block recesses ( 23 ) defined at equal intervals in the outer circumference of the ratchet ( 20 );
an expansion ring ( 30 ) mounted in the annular recess ( 22 ) and having an inner diameter slightly larger than the outer diameter of a portion in the annular recess ( 22 ) of the ratchet ( 20 ); and
at least two clamping blocks ( 40 ) each received in the at least two block recesses ( 23 ) and attached to the expansion ring ( 30 ), each clamping block ( 40 ) having an outwardly facing toothed surface for engagement with the toothed cavity ( 12 ) of the key ( 20 );
wherein the expansion ring ( 30 ) provides a resilient restoring force to the at least two clamping blocks ( 40 ) to cause the clamping blocks ( 40 ) to remain in contact with the toothed cavity ( 12 ). 2. Unidirectional ratchet wrench according to claim 1, wherein the insert ( 21 ) is defined as a regular polygon. 3. A unidirectional ratchet wrench according to claim 1, wherein the expansion ring ( 30 ) is a circular strip. 4. A unidirectional ratchet wrench according to claim 1, wherein the wrench body further comprises two covers ( 50 ) each mounted on opposite openings in the toothed cavity ( 12 ) of the wrench body ( 10 ) to enclose the ratchet ( 20 ) in the toothed cavity ( 12 ). 5. A unidirectional ratchet wrench according to claim 3, wherein the wrench body further comprises two covers ( 50 ) each mounted on opposite openings in the toothed cavity ( 12 ) of the wrench body ( 10 ) to enclose the ratchet ( 20 ) in the toothed cavity ( 12 ).