Tool with a ratchet mechanism
A hand tool or wrench with a ratcheting mechanism. The wrench includes a number of components such as an abutting block and a pawl for use in a bistable ratchet operation. The wrench includes a ratchet mechanism that provides stable seating of the components, so that the mechanism is securely retained in a driving mode, as well as enabling a user to select a driving mechanism with ease so as to improve work efficiency.
1. A tool with a bistable ratchet mechanism, comprising:
a body ( 1 ) having a first chamber ( 11 ), a second chamber ( 12 ) adjacent to the first chamber ( 11 ) and a third chamber ( 13 ) connecting the first and second chambers to one another;
a driving member ( 2 ), being rotatably retained in the first chamber ( 11 ), and having a first pawl portion ( 21 ) arranged around an external portion of the driving member ( 2 );
a stopping member ( 3 ), provided in the third chamber and having a second pawl portion ( 31 ) arranged on a first face, and arranged so that the second pawl portion ( 31 ) engages with the first pawl portion ( 21 ), the stopping member ( 3 ) further having a recess ( 32 ) in a second face of the stopping member ( 3 ), opposite the second pawl portion ( 31 );
a switching member ( 4 ), rotatably provided in the second chamber and comprising a rotating member ( 41 ), the rotating member being radially provided a hole ( 44 ) the rotating member ( 41 ) being further radially provided with a dial member ( 43 ) for manipulating the rotating member ( 41 ); and
an elastic abutting assembly ( 5 ), comprising an elastic member ( 51 ) and an abutting block ( 52 ), the elastic member ( 51 ) in contact with a first end of the abutting block, the first end of the abutting block ( 52 ) and the elastic member ( 51 ) being received in the hole ( 44 ), and the elastic member ( 51 ) biasing the abutting block ( 52 ) toward the a recess ( 32 ) the stopping member ( 3 ), to bias the stopping member ( 3 ) into contact with the driving member ( 2 ); wherein
the mechanism is configurable in a position of unstable equilibrium, a first position of stable equilibrium or a second position of equilibrium, and is configured to transition between the stable and unstable equilibrium positions via non-equilibrium positions by rotating the switching member ( 4 ); wherein:
the position of unstable equilibrium corresponds to a neutral position in which the driving ( 2 ) member is rotatable in two directions relative to the body ( 1 );
in the first stable equilibrium position the stopping member ( 3 ) contacts a first internal wall of the body ( 1 ) and prevents the driving member ( 2 ) from rotating in a first direction relative to the body ( 1 ); and
in the second stable equilibrium position the stopping member ( 3 ) contacts a second internal wall of the body ( 1 ) and prevents the driving member ( 2 ) from rotating in a second direction relative to the body ( 1 ), the second direction being opposite to the first direction; and wherein
positions between the stable and unstable equilibria are non-equilibrium positions because a force biasing the abutting block ( 52 ) is incompletely cancelled by the reaction force ( 71 ) acting on the abutting block ( 52 ) from the stopping member ( 3 ), the resultant force further biasing the stopping ( 3 ) member towards an internal wall of the body ( 1 ).
2. The tool with a ratchet mechanism of claim 1 , wherein rotating the driving member ( 2 ) when the stopping member ( 3 ) is in the position of unstable equilibrium causes the stopping member ( 3 ) to move towards a position of stable equilibrium via a non-equilibrium arrangement.
3. The tool with a ratchet mechanism of claim 1 , wherein the elastic member ( 51 ) is a compression spring.
4. The tool with a ratchet mechanism of claim 1 , wherein rotation of the switching member ( 4 ) changes the location at which the abutting block ( 52 ) contacts the stopping member ( 3 ).
5. The tool with a ratchet mechanism of claim 1 , wherein the mechanism is transitionable from the position of unstable equilibrium to a non-equilibrium position by:
(a) rotating the switching member ( 4 ) and dragging the stopping member ( 3 ) via a frictional interaction between the abutting block ( 52 ) and the recess ( 32 );
(b) pushing the stopping member ( 3 ) with a portion of the switching member ( 4 ), when the switching member ( 4 ) is rotated; and/or
(c) rotating the driving member ( 2 ) relative to the body ( 1 ).
6. The tool with a ratchet mechanism of claim 5 , wherein the transition from the position of unstable equilibrium to a position of stable equilibrium is facilitated by the shape of the recess ( 32 ).
7. The tool with a ratchet mechanism of claim 5 , wherein a transition from the position of unstable equilibrium to a non-equilibrium position occurs at a critical angle of rotation of the switching member ( 4 ).
8. The tool with a ratchet mechanism of claim 1 , wherein the stopping member ( 3 ) is moveable from a position of stable equilibrium to the position of unstable equilibrium by:
(a) rotating the switching member ( 4 ) and dragging the stopping member ( 3 ) via a frictional interaction between the abutting block ( 52 ) and the recess ( 32 ); and/or
(b) pushing the stopping member ( 3 ) with a portion of the switching member ( 4 ), when the switching member ( 4 ) is rotated.
9. The tool with a ratchet mechanism of claim 1 , wherein the transition from the position of unstable equilibrium to a position of stable equilibrium is facilitated by the shape of the recess ( 32 ).
10. The tool with a ratchet mechanism of claim 9 , wherein the recess ( 32 ) comprises a circular section.
11. The tool with a ratchet mechanism of claim 10 , wherein the recess ( 32 ) further comprises linear portions.
12. The tool with a ratchet mechanism of claim 1 , wherein the abutting block ( 52 ) contacts the recess ( 32 ) along a single point or line in all positions of the stopping member ( 3 ).
13. The tool with a ratchet mechanism of claim 1 , wherein the abutting block ( 52 ) contacts the recess ( 32 ) along a single point or line in all stopping member ( 3 ) positions except for the position of unstable equilibrium.
14. The tool with a ratchet mechanism of claim 13 , wherein there are two points or lines of contact between the abutting block ( 52 ) and the recess ( 32 ) when the stopping member ( 3 ) is in the unstable equilibrium position.
15. The tool with a ratchet mechanism of claim 14 , wherein the recess ( 32 ) is symmetric about a central portion of the recess ( 32 ).
16. The tool with a ratchet mechanism of claim 13 , wherein the recess ( 32 ) is symmetric about a central portion of the recess ( 32 ).
17. The tool with a ratchet mechanism of claim 1 , wherein a transition from the position of unstable equilibrium to a non-equilibrium position occurs at a critical angle of rotation of the switching member ( 4 ).
18. The tool with a ratchet mechanism of claim 1 , wherein the position of unstable equilibrium corresponds to a range of rotational orientations of the switching member.