Proofmass suspension assembly for accelerometers

Claim 2

An improved pendulous type of proofmass suspension assembly for an accelerometer having a support structure, a sensitive axis, a proofmass, and sensing means including components thereof carried by said proofmass for detecting a response in said proofmass to an acceleration along said sensitive axis for indicating an acceleration of said accelerometer along said sensitive axis, wherein said proofmass suspension assembly comprises: a frame which is mounted to said support structure; an isolation bridge; one or more isolation bridge flexures; and one or more proofmass flexures; wherein said proofmass flexures and said isolation bridge flexures are thinner than both said isolation bridge and said proofmass in a direction parallel to said sensitive axis when the proofmass is at rest, whereby to support said proofmass for pivotal movement relative to said isolation bridge; wherein said one or more proofmass flexures connect said bridge to one side of said proofmass such that the proofmass is supported in a pendulous manner for limited back and forth movement about an axis adjacent one side of the proofmass and through a resting plane which contains the proofmass when the latter is in its resting position; wherein said isolation bridge is pendulously connected to said frame by said one or more isolation bridge flexures for pendulous movement toward and away from said resting plane; wherein said one or more proofmass flexures are spaced from and are not directly connected in any substantial way with said one or more isolation bridge flexures; and wherein said isolation bridge is supported by said isolation bridge flexures and said proofmass flexures in a sufficiently compliant manner to absorb random strains in order to substantially prevent random strains in said frame and said one or more isolation bridge flexures from reaching said one or more proofmass flexures and said proofmass and thereby possibly produce substantial errors in the output of said sensing means and indicate inaccurately an acceleration of said accelerometer.

Claim 3

The proofmass suspension assembly of claim 1, wherein there are two of said isolation bridge flexures; and wherein said frame is connected with said isolation bridge by each of said two isolation bridge flexures.

Claim 4

The proofmass suspension assembly of claim 2, wherein there are two of said proofmass flexures; and wherein said isolation bridge is connected to each of said proofmass flexures.

Claim 5

The proofmass suspension assembly of claim 3, wherein said two isolation bridge flexures and said two proofmass flexures are all connected with said isolation bridge on the same side of said isolation bridge.

Claim 6

The proofmass suspension assembly of claim 3, wherein the assembly includes only two isolation bridge flexures and only two proofmass flexures.

Claim 7

The proofmass suspension assembly according to claim 4, wherein said frame includes a pair of frame arms, and wherein said two isolation bridge flexures are respectively connected directly to otherwise free ends of said frame arms.

Claim 8

The proofmass suspension assembly according to claim 5, wherein said proofmass is generally rectangular in configuration, and wherein said proofmass flexures are connected to said one side of said proofmass adjacent opposite corners of the proofmass, and wherein said isolation bridge flexures are positioned on opposite sides of the two proofmass flexures.

Claim 9

The proofmass suspension assembly according to claim 1, wherein said assembly includes only one isolation bridge.

Claim 10

The proofmass suspension assembly according to claim 1, wherein there are two of said proofmass flexures connecting said bridge to said proofmass.

Claim 11

A proofmass suspension assembly according to claim 1, wherein said one or more proofmass flexures are connected with one side of said one isolation bridge and wherein said one or more isolation bridge flexures are connected on an opposite side of said bridge.

Claim 12

In a force sensing device in which a pendulous type of proofmass is supported for limited back and forth pivotal movement about an axis adjacent one side of the proofmass and through a resting plane which contains the proofmass when the latter is in its resting position and in which sensing means including components thereof carried by said proofmass are used for detecting a response of said proofmass to a force on said device along a sensitive axis normal to said resting plane and for indicating the magnitude of said force, the improvement comprising a proofmass suspension assembly for supporting said proofmass along one side thereof, said assembly including a frame which is mounted to a cooperating support structure forming part of said force sensing device, an isolation bridge, an isolation bridge flexure means connecting said isolation bridge to said frame, said isolation bridge flexure means being thinner in a direction normal to said resting plane than both said isolation bridge and frame, whereby to support said isolation bridge for movement relative to said frame in directions toward and away from said resting plane, and proofmass flexure means spaced from and not directly connected, in any substantial way, with said isolation bridge flexure means and serving to connect said isolation bridge to said proofmass, said proofmass flexure means being thinner than both said isolation bridge and said proofmass in a direction normal to said resting plane, whereby to support said proofmass for said back and forth pivotal movement relative to said isolation bridge, said isolation bridge being supported by said isolation bridge flexure means and said proofmass flexure means in a sufficiently compliant manner to absorb random strains in order to substantially prevent random strains in said frame and said isolation bridge flexure means from reaching said proofmass flexure means and said proofmass and thereby possibly produce errors in the operation of said sensing means and indicate inaccurately the magnitude of said force.

Claim 13

In a force sensing device in which a pendulous type of proofmass is supported for limited back and forth pivotal movement about an axis adjacent one side of the proofmass and through a resting plane which contains the proofmass when the latter is in its resting position and in which sensing means including components thereof carried by said proofmass are used for detecting a response of said proofmass to a force on said device along a sensitive axis normal to said resting plane and for indicating the magnitude of said force, the improvement comprising a proofmass suspension assembly for supporting said proofmass along one side thereof, said assembly including a frame which is mounted to a cooperating support structure forming part of said force sensing device, an isolation bridge, an isolation bridge flexure means connecting said isolation bridge to said frame, said isolation bridge flexure means being thinner in a direction normal to said resting plane than both said isolation bridge and frame, whereby to support said isolation bridge for movement relative to said frame in directions toward and away from said resting plane, and proofmass flexure means spaced from and not directly connected, in any substantial way, with said isolation bridge flexure means and serving to connect said isolation bridge to said proofmass, said proofmass flexure means being thinner than both said isolation bridge and said proofmass in a direction normal to said resting plane, whereby to support said proofmass for said back and forth pivotal movement relative to said isolation bridge, said isolation bridge being supported by said isolation bridge flexure means and said proofmass flexure means in a sufficiently compliant manner to absorb random strains in order to substantially prevent random strains in said frame and said isolation bridge flexure means from reaching said proofmass flexure means and said proofmass and thereby possibly produce errors in the operation of said sensing means and indicate inaccurately the magnitude of said force.

Claim 14

An improvement according to claim 11 wherein said isolation bridge flexure means includes two separate isolation bridge flexures.

Claim 15

The improvement according to claim 11 wherein said proofmass flexure means includes two proofmass flexures.

Claim 16

The improvement according to claim 11 wherein said proofmass suspension assembly includes only one isolation bridge.

Claim 17

The improvement according to claim 11 wherein said isolation flexure means consists of two isolation flexures, wherein said proofmass flexure means consists of two proofmass flexures, and wherein all four of said flexures are connected to the same side of said isolation bridge.

Claim 18

A pendulous assembly for use in device including means for sensing forces acting on the assembly in a particular direction and for determining the magnitude of those forces, said assembly comprising: (a) a proofmass supporting specific components of said sensing means; and (b) means supporting one end of said proofmass including said specific components of said sensing means for pivotal movement about a given axis back and forth in said particular direction through a resting plane which contains said proofmass in the absence of any of said sensing forces when the proofmass is at rest, said supporting means including a frame, an isolation bridge, isolation bridge flexure means for connecting said isolation bridge to a section of said frame for pivotal movement of said isolation bridge back and forth about said given axis, and proofmass flexure means being separate from and substantially unconnected with said isolation bridge flexure means for connecting said proofmass to said isolation bridge means for pivotal movement of said proofmass back and forth about said given axis, said proofmass flexure means and said isolation bridge flexure means being thinner than both said isolation bridge and said proofmass in a direction normal to said resting plane when the proofmass is at rest, whereby to support said proofmass for pivotal movement relative to said isolation bridge, said isolation bridge being supported by said isolation bridge flexure means and said proofmass flexure means in a sufficiently compliant manner to absorb random strains in order to prevent any random strains in said frame and said isolation bridge flexure means from reaching said proofmass flexure means and said proofmass and thereby possibly produce substantial errors in the operation of said sensing means.

Claim 19

A pendulous assembly for use in device including means for sensing forces acting on the assembly in a particular direction and for determining the magnitude of those forces, said assembly comprising: (a) a proofmass supporting specific components of said sensing means; and (b) means supporting one end of said proofmass including said specific components of said sensing means for pivotal movement about a given axis back and forth in said particular direction through a resting plane which contains said proofmass in the absence of any of said sensing forces when the proofmass is at rest, said supporting means including a frame, an isolation bridge, isolation bridge flexure means for connecting said isolation bridge to a section of said frame for pivotal movement of said isolation bridge back and forth about said given axis, and proofmass flexure means being separate from and substantially unconnected with said isolation bridge flexure means for connecting said proofmass to said isolation bridge means for pivotal movement of said proofmass back and forth about said given axis, said proofmass flexure means and said isolation bridge flexure means being thinner than both said isolation bridge and said proofmass in a direction normal to said resting plane when the proofmass is at rest, whereby to support said proofmass for pivotal movement relative to said isolation bridge, said isolation bridge being supported by said isolation bridge flexure means and said proofmass flexure means in a sufficiently compliant manner to absorb random strains in order to prevent any random strains in said frame and said isolation bridge flexure means from reaching said proofmass flexure means and said proofmass and thereby possibly produce substantial errors in the operation of said sensing means.

Claim 20

An assembly according to claim 16 wherein both the isolation bridge flexure means and the proofmass flexure means are connected to one side of said isolation bridge such that the other side thereof is free-floating.

Claim 21

An assembly according to claim 16 wherein said isolation bridge flexure means is connected to one side of said isolation bridge means and wherein said proofmass flexure means is connected to the opposite side of said isolation bridge.

Claim 22

An assembly according to claim 16 wherein said proofmass flexure means and said isolation bridge flexure means are planar in configuration and extend entirely in said resting plane when said proofmass is at rest.

Claim 23

An improved type of proofmass suspension assembly for an accelerometer having a support structure, a sensitive axis, a proofmass, and sensing means including components thereof carried by said proofmass for detecting a response of said proofmass to an acceleration along said sensitive axis for indicating an acceleration of said accelerometer along said sensitive axis such that random strains in said proofmass might possibly produce substantial errors in the operation of said sensing means by causing random movement of the proofmass and thereby possibly cause inaccuracies in the acceleration output of said accelerometer, whereby said proofmass suspension assembly comprises: a frame which is mounted to said support structure and which can be subjected to random strains without producing substantial errors in the operation of said sensing means so long as those strains do not reach said proofmass; an isolation bridge; one or more isolation bridge flexures which may also be subjected to random strains without producing substantial errors in the output of said sensing means so long as those strains do not reach said proofmass; and one or more proofmass flexures; wherein said frame is connected to said isolation bridge by said one or more isolation bridge flexures; wherein said one or more proofmass flexures connect said bridge to one side of said proofmass only, whereby to support the proofmass in a pendulous manner; wherein said one or more proofmass flexures are spaced from and are not directly connected in any substantial way with said one or more isolation bridge flexures; and wherein said isolation bridge is supported by said isolation bridge flexures and said proofmass flexures in a sufficiently compliant manner to absorb random strains in order to substantially prevent random strains in said frame and said one or more isolation bridge flexures from reaching said one or more proofmass flexures and said proofmass and thereby possibly produce substantial errors in the output of said sensing electronic means and indicate inaccurately an acceleration of said accelerometer; and wherein said one or more proofmass flexures and said one or more isolation bridge flexures are all connected with said isolation bridge on the same side of said bridge.

Claim 24

An improved type of proofmass suspension assembly for an accelerometer having a support structure, a sensitive axis, a proofmass, and sensing means including components thereof carried by said proofmass for detecting a response of said proofmass to an acceleration along said sensitive axis for indicating an acceleration of said accelerometer along said sensitive axis such that random strains in said proofmass might possibly produce substantial errors in the operation of said sensing means by causing random movement of the proofmass and thereby possibly cause inaccuracies in the acceleration output of said accelerometer, whereby said proofmass suspension assembly comprises: a frame which is mounted to said support structure and which can be subjected to random strains without producing substantial errors in the operation of said sensing means so long as those strains do not reach said proofmass; an isolation bridge; one or more isolation bridge flexures which may also be subjected to random strains without producing substantial errors in the output of said sensing means so long as those strains do not reach said proofmass; and one or more proofmass flexures; wherein said frame is connected to said isolation bridge by said one or more isolation bridge flexures; wherein said one or more proofmass flexures connect said bridge to one side of said proofmass only, whereby to support the proofmass in a pendulous manner; wherein said one or more proofmass flexures are spaced from and are not directly connected in any substantial way with said one or more isolation bridge flexures; and wherein said isolation bridge is supported by said isolation bridge flexures and said proofmass flexures in a sufficiently compliant manner to absorb random strains in order to substantially prevent random strains in said frame and said one or more isolation bridge flexures from reaching said one or more proofmass flexures and said proofmass and thereby possibly produce substantial errors in the output of said sensing electronic means and indicate inaccurately an acceleration of said accelerometer; and wherein said one or more proofmass flexures and said one or more isolation bridge flexures are all connected with said isolation bridge on the same side of said bridge.