Guide for top drive unit

A guide for a top drive unit in combination with a rig assembly having a base section, a lower mast section, and an upper mast section, the lower mast section pivotally connected to the base section so the lower mast section and the upper mast section are movable between a substantially horizontal position and a substantially vertical position, the upper mast section being movable relative to the lower mast section between a retracted position and an extended position, the guide comprising:

• a lower track member having a first end, a second end, and a lateral cross-sectional profile, the first end pivotally connected to the lower mast section;
• an upper track member having a first end, a second end, and a lateral cross-sectional profile, the second end of the upper track member pivotally connected to the upper mast section, the first end of the upper track member received in the lower track member so the upper track member telescopes relative to the lower track member between a retracted position and an extended position;
• a slider having a first end, a second end, a lateral transverse profile extending from the first end toward the second end, and a laterally extending stop member spaced from the first end of the slider, the lateral cross-sectional profile of the slider being substantially the same shape and size as the lateral cross-sectional profile of the lower track member, the slider slidably positioned about the upper track member so the slider is movable along the upper track member, the first end of the slider being mateable with the second end of the lower track member;
• and
• a skate slidably positioned about the lower track member to be movable along the lower track member from the first end, to the second end, and onto the slider when the first end of the slider is mated with the second end of the lower track member, when on the slider the skate is engageable with the lateral stop member to cause the skate and the slider to move along the upper track member together,
• wherein the skate is connectable to a top drive unit so the top drive unit is movable along the lower track member and the upper track member.

A rig assembly, comprising:

• a mast having a base section, a lower mast section, and an upper mast section, the lower mast section pivotally connected to the base section so the lower mast section and the upper mast section are movable between a substantially horizontal position and a substantially vertical position, the upper mast section being movable relative to the lower mast section between a retracted position and an extended position;
• a top drive guide comprising:
• a lower track member having a first end, a second end, and a lateral cross-sectional profile, the first end pivotally connected to the lower mast section;
• an upper track member having a first end, a second end, and a lateral cross-sectional profile, the second end of the upper track member pivotally connected to the upper mast section, the first end of the upper track member received in the lower track member so the upper track member telescopes relative to the lower track member between a retracted position and an extended position;
• a slider having a first end, a second end, a lateral transverse profile extending from the first end toward the second end, and a laterally extending stop member spaced from the first end of the slider, the lateral cross-sectional profile of the slider being substantially the same shape and size as the lateral cross-sectional profile of the lower track member, the slider slidably positioned about the upper track member so the slider is movable along the upper track member, the first end of the slider being mateable with the second end of the lower track member;
• and
• a skate slidably positioned about the lower track member to be movable along the lower track member from the first end, to the second end, and onto the slider when the first end of the slider is mated with the second end of the lower track member, when on the slider the skate is engageable with the lateral stop member to cause the skate and the slider to move along the upper track member together;
• and
• a top drive unit connected to the skate so the top drive unit is movable along the lower track member and the upper track member.