Vibration isolation system
AssigneeMinus K. Technology, Inc.
InventorDavid L. Platus
Life of this patent
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Abstract
A vibration isolation system utilizes various configurations of elastic structures loaded to approach a point of elastic instability. In one form of the invention, the system uses a combination of a negative-stiffness mechanism and a positive spring to support a payload and provide low net stiffness in the vertical direction. Horizontal motion is generally isolated by utilizing one or more axially-symmetric columns loaded to approach their critical buckling loads to provide low stiffness in any horizontal direction.
Claims38
An omnidirectional vibration-isolating suspension system for supporting an object having mass in an acceleration field and maintaining the object in an equilibrium position relative to a base while suppressing transmission of vibratory motion between the object and base, comprising:
- a first isolator including a first elastic structure having first and second ends spaced apart to define an axial direction, said first elastic structure having transverse stiffness in response to displacement of said first end relative to said second end in any direction substantially transverse to the axial direction without rotation of said second end and stiffness in the axial direction to support the object, said first elastic structure having a point of elastic instability in response to loading in the axial direction where at the point of elastic instability said first elastic structure has substantially zero transverse stiffness, said first elastic structure being loaded in the axial direction to approach its point of elastic instability to cause a substantial reduction of the transverse stiffness while maintaining sufficient axial stiffness to support the object;
- and
- a second isolator operatively connected axially in series with said first isolator, said second isolator including a second elastic structure adapted to receive a compressive loading force, said second elastic structure having an end for supporting the object and axial stiffness, said second elastic structure having a point of elastic instability in response to application of a compressive loading force to said second elastic structure where at the point of elastic instability said second elastic structure has substantially zero axial stiffness, said second elastic structure being loaded to approach its point of elastic instability to cause a substantial reduction of its axial stiffness, wherein said first and second isolators have load-supporting capability to support the object in the axial direction and are connected between the object and base.
An omnidirectional vibration-isolating suspension system for supporting an object in an equilibrium position relative to a base while suppressing transmission of vibratory motion between the object and the base comprising:
- at least one composite suspension apparatus connected between the object and the base, comprising:
- a first suspension device having first and second ends spaced apart to define an axial direction, said first suspension device having force-supporting capability in the axial direction for supporting the object and relatively low stiffness in a direction lateral to the axial direction;
- and
- a second suspension device operatively connected axially in series with said first suspension device, said second suspension device including:
- spring means adapted to provide positive stiffness in the axial direction and having force supporting capability in the axial direction for supporting the object;
- and
- means for producing negative stiffness operatively connected with said spring means wherein said spring means and said negative-stiffness-producing means combine to produce low axial stiffness of the second suspension device which is the algebraic sum of the positive and negative stiffnesses.
A method for reducing transmission of vibrations having a component in an axial direction and any direction lateral to the axial direction between an object and a base, comprising the steps of:
- supporting the object relative to the base on a composite suspension apparatus including a first isolating device having first and second ends spaced apart in an axial direction and having sufficient axial stiffness to support the object and relatively low stiffness in any lateral direction and a second suspension device axially in series with the first isolating device and having spring means which exhibit positive axial stiffness to support the object;
- and
- applying negative stiffness between the object and the base for counteracting the positive axial stiffness of said spring means.
In a vibration-isolating system utilizing a uniaxial apparatus for suppressing the transmission of vibratory motion having a component in an axial direction between an object and a base, the improvement comprising:
- at least one elastic member connected to the uniaxial apparatus, each elastic member having a first end and second end spaced apart in the axial direction and having sufficient axial stiffness to support the object and low stiffness in any direction transverse to the axial direction for suppressing transmission of any vibratory motion transverse to the axial direction, the uniaxial apparatus and elastic member being disposed between the object and the base.
A vibration-isolating suspension system for supporting an object in an equilibrium position relative to a base while suppressing the transmission of vibratory motion between the object and the base, comprising:
- a plurality of elastic members disposed between the object and the base, each elastic member having a first end and a second end spaced apart to define an axial direction, each of said members having axial stiffness to support the object and transverse stiffness in response to the displacement of said first end relative to said second end in any direction substantially transverse to the axial direction without rotation of said second end, each elastic member having a point of elastic instability in response to loading in the axial direction where at the point of elastic instability each member has zero or near zero transverse stiffness, each elastic member being loaded in the axial direction to approach its point of elastic instability to cause substantial reduction of the transverse stiffness of each member.
Dependencies are inferred from the claim text.