1. A wrench comprising:
a handle comprising a head yoke and a spring depressible first detent disposed on the bottom of the head yoke;
a positioning member comprising a projection pivotably secured to the head yoke, the projection having a notch on the outer surface which is urged by the first detent, a cavity opposite the projection, and a spring depressible second detent disposed on one side of the cavity; and
a driving member comprising a protrusion having first and second recesses on both sides respectively, the protrusion being releasably mounted in the cavity with the second detent urging against one of the first and second recesses,
wherein the first detent is adapted to urge against the notch by pivoting the positioning member about the head yoke so as to dispose the positioning member at an inclined angle with respect to the head yoke.
2. The wrench of claim 1, wherein each of the first and second detents is a steel ball.
3. A wrench comprising:
a handle comprising two head yokes and two spring depressible first detents each disposed on the bottom of either head yoke;
two positioning members each comprising a projection pivotably secured to either head yoke, the projection having a notch on the outer surface which is urged by the first detent, a cavity opposite the projection, and a spring depressible second detent disposed on one side of the cavity; and
two driving members each comprising a protrusion having first and second recesses on both sides respectively, the protrusion being releasably mounted in the cavity with the second detent urging against one of the first and second recesses, wherein at either head yoke the first detent is adapted to urge against the notch by pivoting the positioning member about the head yoke so as to dispose the positioning member at an inclined angle with respect to the head yoke.
4. The wrench of claim 3, wherein each of the first and second detents is a steel ball.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A device for grinding (1) non-metal parts (2) comprising at least one motor-driven rotating shaft (11) inside a receptacle that receives non-metal parts that are to be ground, said shaft (11) having a plurality of teeth (8) intended to shred and grind said non-metal parts (2), said teeth (8) being arranged radially in rows around the periphery of shaft (11) so as to cooperate, when they rotate, with teeth (15) of at least one fixed comb (4, 4a, 4b) attached to the receptacle and dividing the receptacle into an upper part (5) located above comb (4, 4a, 4b) and a lower part (6) located underneath comb (4, 4a, 4b) characterised in that said fixed comb (4, 4a, 4b) comprises an electrically conducting base (41, 42) held at a specific potential and an electrically conducting surface (14) that faces the upper part (5) of the receptacle and is electrically insulated from said base (41, 42) and held at a potential that is different to that of base (41, 42) so as to detect the presence of metal parts by making the electrical circuit thus produced.
2. A grinding device as claimed in claim 1, characterised in that it comprises a plurality of combs (3, 4) capable of detecting the presence of metal parts either side of the longitudinal median plane of the grinding device (1).
3. A grinding device as claimed in claim 1, characterised in that the electrical potentials of the base (41, 42) and the teeth (8) of the motor-driven rotating shaft (11) are identical.
4. A grinding device as claimed in claim 3, characterised in that the base (41, 42) and teeth (8) of motor-driven rotating shaft (11) are held at zero potential.
5. A grinding device as claimed in claim 1, characterised in that conducting surface (14) consists of a conducting sheet (43, 44) secured on base (41, 42) by at least one electrically insulated fastener.
6. A grinding device as claimed in claim 5, characterised in that the electrically insulated fastener consists of a screw (47) held at the same potential as that of base (41, 42), said screw (47) passing through a hole (48) in sheet (43, 44) and securing sheet (43, 44) by means of its head.
7. A grinding device as claimed in claim 6, characterised in that an electrically insulating hardenable material (10) is inserted between base (41, 42), sheet (43, 44) and screw (47) so as to electrically insulate sheet (43, 44) from base (41, 42).
8. A grinding device as claimed in claim 1, characterised in that the conducting surface (14) consists of an electrically conducting section (51) accommodated in a groove (50) of matching shape made in the upper surface of the comb and extending substantially along all or part of its periphery and also along its median plane, said section being coated in an insulating resin before being bonded into said groove.
9. A grinding device as claimed in claim 8, characterised in that said sections (51) of a single row of combs are electrically connected to each other by means of cone-point set screws or screws with a ball at both their ends and housed in an outer enclosure made of an electrically non-conducting material having a thread, each of said screws being intended to be accommodated in a bore in the lateral surface of each of the combs and opening out into groove (50) which they have, so as to be in contact with conducting section (51).
10. A grinding device as claimed in claim 1, characterised in that conducting sheet (43, 44) or section (51) is electrically connected to a control unit of device (1) intended to stop rotation of motor-driven shaft (11) when the circuit is made by a metal part.