Hydraulic torque wrench

1. A hydraulic torque wrench for applying a rotational force to an object, the torque wrench comprising:

a body;

an object engaging portion for engaging the object to which rotational force is to be applied, the engaging portion having an engaging aperture having internal surfaces arranged to engage the object and a plurality of first ratchet teeth on an external surface thereof;

a support member for retaining the object engaging portion, the support member movable relative to said body and said object engaging portion;

at least one ratchet mechanism cooperating with said first ratchet teeth to facilitate the application of the rotational force to said object engaging portion in a first rotational direction in response to a force being applied to said support member in a first substantially linear direction and said ratchet mechanism preventing the application of a rotational force in a second rotational direction, opposite to said first rotational direction; and

side plates extending from said body at least partially covering a junction between said object engaging portion and said support member, said side plates comprising an aperture through which said object can extend when the wrench is in use, wherein said aperture has a shape formed by two non-concentric overlapping circles comprising a first circle having a first centerpoint and a second circle having a second centerpoint, the centerpoint of the first circle located closer to the centerpoint of the second circle than to a periphery of the second circle.

2. The hydraulic torque wrench according to claim 1 , wherein said first and second circles have different diameters.

3. The hydraulic torque wrench according to claim 1 , wherein said first circle is concentric with an axis of rotation of said object engaging portion.

4. The hydraulic torque wrench according to claim 1 , wherein said ratchet mechanism comprises a ratchet member having at least one second ratchet tooth for engaging said first ratchet teeth.

5. The hydraulic torque wrench according to claim 1 , wherein said engaging aperture is substantially hexagonal.

6. The hydraulic torque wrench according to claim 1 , further comprising at least one hydraulic ram for applying said force in said first substantially linear direction to said support member.

7. The hydraulic torque wrench according to claim 6 , further comprising at least one connector portion for connecting said hydraulic ram to a supply of hydraulic fluid.

8. The hydraulic torque wrench according to claim 7 , further comprising at least one hydraulic pump unit for supplying said hydraulic fluid under pressure to said hydraulic ram via said connector portion.

9. A hydraulic torque wrench for applying a rotational force to an object, the torque wrench comprising:

a body;

an object engaging portion for engaging the object to which rotational force is to be applied, the engaging portion having an engaging aperture having internal surfaces arranged to engage the object and a plurality of first ratchet teeth on an external surface thereof;

a support member for retaining the object engaging portion, the support member movable relative to said body and said object engaging portion;

at least one ratchet mechanism cooperating with said first ratchet teeth to facilitate the application of the rotational force to said object engaging portion in a first rotational direction in response to a force being applied to said support member in a first substantially linear direction and said ratchet mechanism preventing the application of a rotational force in a second rotational direction, opposite to said first rotational direction; and

side plates extending from said body at least partially covering a junction between said object engaging portion and said support member, said side plates comprising an aperture through which said object can extend when the wrench is in use, wherein said aperture has a shape formed by two non-concentric overlapping circles comprising a first circle having a first centerpoint and a second circle having a second centerpoint, and wherein the first centerpoint of the first circle is located within the second circle and the second centerpoint of the second circle is located within the first circle.

10. A hydraulic torque wrench for applying a rotational force to an object, the torque wrench comprising:

a body;

an object engaging portion for engaging the object to which rotational force is to be applied, the engaging portion having an engaging aperture having internal surfaces arranged to engage the object and a plurality of first ratchet teeth on an external surface thereof;

a support member for retaining the object engaging portion, the support member movable relative to said body and said object engaging portion;

at least one ratchet mechanism cooperating with said first ratchet teeth to facilitate the application of the rotational force to said object engaging portion in a first rotational direction in response to a force being applied to said support member in a first substantially linear direction and said ratchet mechanism preventing the application of a rotational force in a second rotational direction, opposite to said first rotational direction; and

side plates extending from said body at least partially covering a junction between said object engaging portion and said support member, said side plates comprising an aperture through which said object can extend when the wrench is in use, wherein said aperture has a shape formed by two non-concentric overlapping circles comprising a first circle having a first centerpoint and a second circle having a second centerpoint, wherein a reference line connects the first centerpoint of the first circle to the second centerpoint of the second circle without intersecting a periphery of either of the first and second circles.