Working a natural or synthetic hard stone such as a gemstone

Apparatus for working a natural or synthetic stone having a Mohs hardness greater than about 5, using a tool, comprising:

• a support member;
• a mounting member for mounting a stone holder or a tool holder, the mounting member being movable relative to the support member to provide feed and apply a working force between the stone and the tool;
• a spring for applying to the mounting member an alterable biasing force which can, at will, be either in a direction for decreasing said working force or in a direction for increasing said working force, said spring comprising a first portion acting on the mounting member for applying said biasing force and a second portion which is movable relative to said first portion and to said support member, to alter said biasing force;
• a sensor responsive to the relative positions of said first and second portions of the spring and thereby responsive to said biasing force;
• an actuating member for moving said second portion of the spring relative to said support member, whereby said biasing force can be altered and whereby said biasing force can be directed by said actuating member to be in a direction for decreasing said working force or in a direction for increasing said working force;
• and
• a microprocessor responsive to said sensor for causing said actuating member to move said second portion relative to said support member and thereby alter said biasing force and control said working force.

Apparatus for working a natural or synthetic stone having a Mohs hardness greater than about 5, using a tool, comprising:

• a support member;
• a mounting member for mounting a stone holder or a tool holder, the mounting member being movable relative to the support member to provide feed and apply a working force between the stone and the tool;
• a spring for applying to the mounting member an alterable biassing force for altering said working force;
• an actuating member for actuating the spring to alter said biassing force, which actuating member is movable about a first axis;
• a follower lever which is movable about a second axis spaced from said first axis in a direction at right angles to the longitudinal axis of the follower lever;
• a link connecting the actuating member and the follower lever at positions remote from the first and second axes so that the actuating member and the follower lever form a parallel linkage;
• and
• a sensor responsive to said biassing force, said sensor comprising a first element fixed relative to the mounting member and a second element fixed relative to said link.

Apparatus for working a natural or synthetic stone having a Mohs hardness greater than about 5, using a tool, comprising:

• a support member;
• a mounting member for mounting a stone holder or a tool holder, the mounting member being movable relative to the support member to provide feed and apply a working force between the stone and the tool;
• a spring for applying to the mounting member a biassing force for altering said working force, the spring extending in a direction generally at right angles to the direction of relative movement between the mounting member and the support member and having a first portion acting on the mounting means and a second portion which is movable relative to said first portion and to said support member to alter said biassing force;
• and
• an actuating member for altering said biassing force by moving said second portion relative to said support member to bend or unbend said spring about an axis generally at right angles to said relative movement and to said direction.

Apparatus for working a facet on a natural or synthetic stone having a Mohs hardness greater than about 5, using a tool, comprising:

• a support member;
• a mounting member for mounting a stone holder, the mounting member being movable substantially rectilinearly relative to the support member to provide feed and apply a working force between the stone and the tool, and the mounting member being rotatable relative to the support member about an axis of relative rotation which intersects the tool;
• a spring for applying to the mounting member an alterable biasing force which can, at will, be either in a direction for decreasing said working force or in a direction for increasing said working force, the spring having a portion engaging on said axis a part which is rigid with the mounting member regarding in the direction of said axis, and
• an actuating member for actuating the spring, whereby said biasing force can be altered and whereby said biasing force can be directed by said actuating member to be directed in a direction for decreasing said working force or in a direction for increasing said working force.

Apparatus for working a natural or synthetic stone having a Mohs hardness greater than about 5, using a tool, comprising:

• a support member;
• a mounting member for mounting a stone holder or a tool holder, the mounting member being movable relative to the support member to provide feed and apply a working force between the stone and the tool, the mounting member being rotatable relative to the support member about an axis of relative rotation intersecting the tool;
• a spring for applying to the mounting member an alterable biasing force which can, at will, be either in a direction for decreasing said working force or in a direction for increasing said working force, said spring comprising a first portion engaging on said axis a part which is rigid with the mounting member regarding movement in the direction of said axis, for applying said biasing force, and a second portion which is movable relative to said first portion and to said support member, to alter said biasing force;
• an actuating member for moving said second portion of the spring relative to said support member, to alter said biasing force, said actuating member being movable about a second axis;
• a follower lever having a longitudinal axis, which follower lever is movable about a third axis spaced from and parallel to said second axis;
• a link connecting the actuating member and the follower lever at positions remote from the second and third axes whereby the actuating member and the follower lever form a parallel linkage;
• a sensor responsive to said biasing force, said sensor comprising a first element fixed relative to the mounting member and a second element fixed relative to said link;
• and
• a microprocessor responsive to said sensor for causing said actuating member to move said second portion relative to said support member and thereby alter said biasing force and control said working force.

Apparatus for working a natural or synthetic stone having a Mohs hardness greater than about 5, using a tool, comprising;

• a support member;
• a mounting member for mounting a stone holder or a tool holder, the mounting member being freely movable relative to the support member under the force of gravity to provide feed and apply a working force between the stone and the tool;
• a spring for applying to the mounting member an alterable biasing force which can at will be either in a direction for decreasing said gravity force or in a direction for increasing said gravity force, to provide a resultant working force of which one component is the force of gravity and another component is the biasing force, which spring in use before the stone contacts the tool suspends the mounting member;
• and
• a member for actuating the spring whereby said biasing force can be altered and whereby said biasing force can be directed by said actuating member to be in a direction for decreasing said working force or in a direction for increasing said working force.

Apparatus for working a natural or synthetic stone having a Mohs hardness greater than about 5, using a tool, comprising:

• a support member;
• a mounting member for mounting a stone holder or a tool holder, the mounting member being movable relative to the support member to provide feed and apply a working force between the stone and the tool;
• a rod or leaf spring for applying to the mounting member a biasing force which can, at will, be either in a direction for decreasing said working force or in a direction for increasing said working force, the spring having a first portion acting on the mounting means and a second portion which is movable relative to said first portion and to said support member to alter said biasing force, and
• an actuating member for altering said biasing force by moving said second portion relative to said support member to bend or unbend said spring about an axis generally at right angles to said relative movement and to said direction, whereby said biasing force can be altered and whereby said biasing force can be directed by said actuating member to be in a direction for decreasing said working force or in a direction for increasing said working force.