Swing clamp

In a hydraulically actuatable swing clamp, particularly for the clamping of objects such as workpieces, tools and fixtures on a machine, having a piston which is arranged in a housing, the piston having a piston rod which extends in sealed manner out of the housing, carries a clamping arm for clamping the object at a clamping position and carrying out, in addition to an axial clamping movement, a rotary movement corresponding to a guide device, the rotary movement effecting a swinging of the clamping arm, the guide device including a control bolt normally non-rotatable with respect to the housing and extending into the piston, and at least one cam groove provided in a guide surface between the control bolt and the piston, the cam groove having a helical section for the swinging and simultaneous stroke movement of the clamping arm and an axial section for pure clamping movement of the clamping arm, and guide means arranged on the piston or control bolt for engaging the cam groove, the improvement wherein

• said cam groove constitutes means for swinging said clamping arm to and from an intermediate position above a clamping plane, said intermediate position being rotated by a predetermined angle relative to said clamping position, and to and from a rest position below said clamping plane, said rest position being rotated relative to said clamping position by a second angle, said second angle is twice said predetermined angle,
• said cam groove includes at least,
• two first axial sections with which said guide means is engaged when said clamping arm is in and for effecting said clamping position and said rest position, respectively,
• two second axial sections with which said guide means is engaged when said clamping arm is in and for effecting said intermediate position, said two second axial sections are disposed above and alternately between said first axial sections, respectively,
• helical sections communicating each of said second axial sections with both of said first axial sections adjacent thereto, in the manner that an upper end of said first axial sections communicates with a central region of respective adjacent of said second axial sections via a first of said helicaal sections and a lower end of said respective second axial sections communicates with an upper region of the other adjacent said first axial section, respectively, via a second of said helical sections.

In a hydraulically actuatable swing clamp, particularly for the clamping of objects such as workpieces, tools and fixtures on a machine, having a piston which is arranged in a housing, the piston having a piston rod which extends in sealed manner out of the housing, carries a clamping arm for clamping the object at a clamping position and carrying out, in addition to an axial clamping movement, a rotary movement corresponding to a guide device, the rotary movement effecting a swinging of the clamping arm, the guide device including a control bolt normally non-rotatable with respect to the housing and extending into the piston, and at least one cam groove provided in a guide surface between the control bolt and the piston, the cam groove having a helical section for the swinging and simultaneous stroke movement of the clamping arm and an axial section for pure clamping movement of the clamping arm, and guide means arranged on the piston or control bolt for engaging the cam groove, the improvement wherein

• said cam groove constitutes means for swinging said clamping arm to and from an intermediate position above a clamping plane, said intermediate position being rotated by a predetermined angle relative to said clamping position, and to and from a rest position below said clamping plane, said rest position being rotated relative to said clamping position by a second angle,
• said cam groove includes,
• a first axial section,
• a first helical section communicating with said first axial section,
• a second axial section communicating with said first helical section,
• a second helical section communicating with said second axial section,
• a third axial section corresponding to said first axial section, said third axial section communicates with said second helical section, said second axial section is offset by said predetermined angle relative to said first axial section,
• a closed loop portion connecting said first and third axial sections, said closed loop portion by-passes said second axial section such that said guide means sequentially moves from the clamping position in one of said first and third axial sections to the intermediate position in the second axial section, and to the rest position in the other of said first and third axial sections, and then by-passes the intermediate position around the closed loop portion in moving from the rest position to the clamping position, and
• an extra axial section communicating with said closed loop portion.

In a hydraulically actuatable swing clamp, particularly for the clamping of objects such as workpieces, tools and fixtures on a machine, having a single piston which is arranged in a housing, the piston having a piston rod which extends in sealed manner out of the housing, carries a clamping arm for clamping the object at a clamping position and carrying out, in addition to an axial clamping movement, a rotary movement corresponding to a guide device, the rotary movement effecting a swinging of the clamping arm, the guide device including a control bolt normally non-rotatable with respect to the housing and extending into the piston, and at least one cam groove provided in a guide surface between the control bolt and the piston, the cam groove having a helical section for the swinging and simultaneous stroke movement of the clamping arm and an axial section for pure clamping movement of the clamping arm, and guide means arranged on the piston or control bolt for engaging the cam groove, the improvement wherein

• said cam groove constitutes means for swinging said clamping arm to and from an intermediate position above a clamping plane, said intermediate position being rotated by a predetermined angle relative to said clamping position, and to and from a rest position below said clamping plane, said rest position being rotated relative to said clamping position by a second angle.