Force transducer with elongate vibrating member

Claim 2

A transducer responsive to force comprising, an elongate vibrating member; first transverse-node-forming means at which one portion of the elongate member is fixed; second transversenode-forming means incLuding at least two rotatable members arranged to cooperate in preventing transverse movement of another portion of the elongate member therebetween; drive means for exciting transverse vibration of the elongate member in the length thereof between said first and second transverse-nodeforming means; means for applying an axial force to said elongate member; and sensing means for supplying a signal representative of a characteristic of the said vibration, the said rotatable members being arranged to roll when the said other portion moves relative to the said one portion in the axial direction of the elongate member in response to an axially directed force applied to the elongate member.

Claim 3

A transducer as claimed in claim 1, wherein the elongate member is of uniform cross section.

Claim 4

A transducer responsive to force comprising, an elongate vibrating member of oblong cross section throughout its length; first transverse-node-forming means at which one portion of the elongate member is fixed; second transverse-node-forming means including at least two rotatable members arranged to cooperate in preventing transverse movement of another portion of the elongate member therebetween; drive means for exciting transverse vibration of the elongate member in the length thereof between said first and second transverse-node-forming means and in a plane containing the minor axis of said oblong cross section; means for applying an axial force to said elongate member; and sensing means for supplying a signal representative of a characteristic of the said vibration, the said rotatable members being arranged to roll when the said other portion moves relative to the said one portion in the axial direction of the elongate member in response to an axially directed force applied to the elongate member.

Claim 5

A transducer responsive to force comprising, an elongate vibrating member of oblong cross section throughout its length; first transverse-node-forming means at which one portion of the elongate member is fixed; second transverse-node-forming means including at least two rotatable members arranged to cooperate in preventing transverse movement of another portion of the elongate member therebetween; drive means for exciting transverse vibration of the elongate member in the length thereof between said first and second transverse-node-forming means and in a plane containing the minor axis of said oblong cross section; means for applying an axial force to said elongate member; and sensing means for supplying a signal representative of a characteristic of the said vibration, the said rotatable members being arranged to roll when the said other portion moves relative to the said one portion in the axial direction of the elongate member in response to an axially directed force applied to the elongate member.

Claim 6

A transducer as claimed in claim 3, wherein the said oblong cross section is rectangular.

Claim 7

A transducer as claimed in claim 1, wherein the rotatable members are roller members which have their axis parallel to one another and lying in planes to which the axis of the elongate member is perpendicular.

Claim 8

A transducer responsive to force comprising, an elongate vibrating member; first transverse-node-forming means at which one portion of the elongate member is fixed; second transverse-node-forming means including at least two rotatable members arranged to cooperate in preventing transverse movement of another portion of the elongate member therebetween said transverse-node-forming means comprising clamping means with respective screw-threaded tightening means for independently tightening the clamping means on the respective portion of the elongate member; drive means for exciting transverse vibration of the elongate member in the length thereof between said first and second transverse-node-forming means; means for applying an axial force to said elongate member; and sensing means for supplying a signal representative of a characteristic of the said vibration, the said rotatable members being arranged to roll when the said other portion moves relative to the said one portion in the axial direction of the elongate member in response to an axially directed force applied to the elongate member.

Claim 9

A transducer responsive to force comprising, an elongate vibrating member; first transverse-node-forming means at which one portion of the elongate member is fixed; second transverse-node-forming means including at least two rotatable members arranged to cooperate in preventing transverse movement of another portion of the elongate member therebetween said transverse-node-forming means comprising clamping means with respective screw-threaded tightening means for independently tightening the clamping means on the respective portion of the elongate member; drive means for exciting transverse vibration of the elongate member in the length thereof between said first and second transverse-node-forming means; means for applying an axial force to said elongate member; and sensing means for supplying a signal representative of a characteristic of the said vibration, the said rotatable members being arranged to roll when the said other portion moves relative to the said one portion in the axial direction of the elongate member in response to an axially directed force applied to the elongate member.

Claim 10

A transducer as claimed in claim 6, wherein the clamping means include a frame member in which the elongate member is located and the tightening means are screw threadedly engaged.

Claim 11

A transducer responsive to force, comprising: an elongate, flat-sided, stiff but resilient member of ferromagnetic metal; a supporting frame for the elongate member; a first pair of clamping members with respective flat clamping faces arranged to bear against respective opposed flat sides of the elongate member at one portion of the elongate member; first screw-threaded tightening means screw threadedly engaged with the frame and arranged for tightening clamping action by the first pair of clamping members on the said one portion of the elongate member; a second pair of clamPing members with respective flat clamping faces arranged to bear against the said respective opposed flat sides at another portion of the elongate member; at least four rotatable members arranged in pairs to roll on respective further flat faces of the second clamping members without sliding when the other portion moves in the axial direction of the elongate member in response to an axially directed force applied to the elongate member; second screw-threaded tightening means screw threadedly engaged with the frame and arranged for tightening clamping action by the second clamping members on the said other portion of the elongate member; an intermediate member disposed between the second tightening means and one pair of the rotatable members and having a flat face parallel to the respective further flat face of the second clamping member on which the said one pair of rotatable members is arranged to roll; a drive coil mounted in the frame and arranged to operate on the elongate member intermediate the first and second clamping members; a pickup coil mounted in the frame and arranged to operate on the elongate member intermediate the first and second clamping members; respective cores for the drive and pickup coils; and respective ferromagnetic containers for the drive and pickup coils, each container being arranged and shaped to form with the respective core and the elongate member a substantially closed magnetic circuit.

Claim 12

A transducer responsive to force, comprising: an elongate, flat-sided, stiff but resilient member of ferromagnetic metal; a supporting frame for the elongate member; a first pair of clamping members with respective flat clamping faces arranged to bear against respective opposed flat sides of the elongate member at one portion of the elongate member; first screw-threaded tightening means screw threadedly engaged with the frame and arranged for tightening clamping action by the first pair of clamping members on the said one portion of the elongate member; a second pair of clamPing members with respective flat clamping faces arranged to bear against the said respective opposed flat sides at another portion of the elongate member; at least four rotatable members arranged in pairs to roll on respective further flat faces of the second clamping members without sliding when the other portion moves in the axial direction of the elongate member in response to an axially directed force applied to the elongate member; second screw-threaded tightening means screw threadedly engaged with the frame and arranged for tightening clamping action by the second clamping members on the said other portion of the elongate member; an intermediate member disposed between the second tightening means and one pair of the rotatable members and having a flat face parallel to the respective further flat face of the second clamping member on which the said one pair of rotatable members is arranged to roll; a drive coil mounted in the frame and arranged to operate on the elongate member intermediate the first and second clamping members; a pickup coil mounted in the frame and arranged to operate on the elongate member intermediate the first and second clamping members; respective cores for the drive and pickup coils; and respective ferromagnetic containers for the drive and pickup coils, each container being arranged and shaped to form with the respective core and the elongate member a substantially closed magnetic circuit.

Claim 13

A transducer as claimed in claim 8, wherein one end of the elongate member projects beyond the second clamping members and is secured to rigid force-transmitting means.

Claim 14

A transducer as claimed in claim 8, wherein adjustable displacement-limiting means are provided on the frame for limiting displacement of the said force-transmitting means.

Claim 15

A transducer as claimed in claim 8, wherein the said force-transmitting means is rigidly secured to a pressure-responsive diaphragm.

Claim 16

A transducer as claimed in claim 8, wherein a maintaining amplifier couples the pickup coil to the drive coil.

Claim 17

A transducer as claimed in claim 12, wherein the said frame is mounted in a first protective enclosure and the amplifier is mounted in a second protective enclosure.

Claim 18

A transducer responsive to force, comprising: a monolithic metal frame member having a channel therein; an elongate flat-sided, stiff but resilient member of ferromagnetic metal, the elongate member being of uniform cross section and disposed in the said channel; a pair of substantially rectangular first metal blocks respectively in contact over an area with opposite flat sides of the elongate member at one portion of the elongate member; at least one first cap-pointed setscrew which is screw threadedly engaged with the frame member, has its point arranged to bear against one of the first metal blocks on the side thereof remote from the side thereof which is in contact with the elongate member, and has its axis lying in a plane containing the elongate member; a pair of substantially rectangular second metal blocks respectively in contact over an area with the said opposite flat sides of the elongate member at another portion of the elongate member; two pairs of roller members arranged to have their axes lying parallel to one another in planes to which the axis of the elongate member is perpendicular, each pair of roller members being in contact with a respective one of the second metal blocks at the side thereof remote from the side thereof which is in contact with the elongate member; at least one substantially rectangular third metal block, the said one third metal block being arranged to have one side thereof facing the said remote side of one of the second metal blocks and in contact with the pair of roller members which is in contact with the said remote side; at least one second cap-pointed setscrew which is screw threadedly engaged with the frame member, has its point arranged to bear against the saId one third metal block on the side thereof remote from the side thereof which is in contact with the said one pair of roller members, and has its axis lying along a line which passes between the axes of the said one pair of roller members and between the axes of the other pair of roller members; a drive coil; a pickup coil; respective permanent magnet cores for the drive and pickup coils; respective ferromagnetic containers for the drive and pickup coils, each container being mounted in the frame member, extending into the said channel, and being shaped to form with the respective core and a respective portion of the elongate member a substantially closed magnetic circuit; and a rigid force-transmitting member secured to the said other portion of the elongate member, the elongate member, the said metal blocks, and the roller members being clamped in the said channel by the said setscrews, the roller members and the said second metal blocks being spaced from the frame member to follow axial movement of the said other portion of the elongate member relative to the frame member, and a length of the elongate member, which length includes the said respective portions, extending from the first metal blocks to the second metal blocks, being sharply defined thereby, and being spaced from the frame member for transverse vibration.

Claim 19

A transducer responsive to force, comprising: a monolithic metal frame member having a channel therein; an elongate flat-sided, stiff but resilient member of ferromagnetic metal, the elongate member being of uniform cross section and disposed in the said channel; a pair of substantially rectangular first metal blocks respectively in contact over an area with opposite flat sides of the elongate member at one portion of the elongate member; at least one first cap-pointed setscrew which is screw threadedly engaged with the frame member, has its point arranged to bear against one of the first metal blocks on the side thereof remote from the side thereof which is in contact with the elongate member, and has its axis lying in a plane containing the elongate member; a pair of substantially rectangular second metal blocks respectively in contact over an area with the said opposite flat sides of the elongate member at another portion of the elongate member; two pairs of roller members arranged to have their axes lying parallel to one another in planes to which the axis of the elongate member is perpendicular, each pair of roller members being in contact with a respective one of the second metal blocks at the side thereof remote from the side thereof which is in contact with the elongate member; at least one substantially rectangular third metal block, the said one third metal block being arranged to have one side thereof facing the said remote side of one of the second metal blocks and in contact with the pair of roller members which is in contact with the said remote side; at least one second cap-pointed setscrew which is screw threadedly engaged with the frame member, has its point arranged to bear against the saId one third metal block on the side thereof remote from the side thereof which is in contact with the said one pair of roller members, and has its axis lying along a line which passes between the axes of the said one pair of roller members and between the axes of the other pair of roller members; a drive coil; a pickup coil; respective permanent magnet cores for the drive and pickup coils; respective ferromagnetic containers for the drive and pickup coils, each container being mounted in the frame member, extending into the said channel, and being shaped to form with the respective core and a respective portion of the elongate member a substantially closed magnetic circuit; and a rigid force-transmitting member secured to the said other portion of the elongate member, the elongate member, the said metal blocks, and the roller members being clamped in the said channel by the said setscrews, the roller members and the said second metal blocks being spaced from the frame member to follow axial movement of the said other portion of the elongate member relative to the frame member, and a length of the elongate member, which length includes the said respective portions, extending from the first metal blocks to the second metal blocks, being sharply defined thereby, and being spaced from the frame member for transverse vibration.

Claim 20

A transducer as claimed in claim 14, wherein the other of the first metal blocks is held against the frame member in the said channel by the clamping action of the first setscrew.

Claim 21

A transducer as claimed in claim 14, wherein the elongate member is of oblong rectangular cross section, the said opposite flat sides of the elongate member are the wider side faces thereof, and the axes of the drive and pickup coils are perpendicular to the said opposite flat sides.

Claim 22

A transducer as claimed in claim 14, wherein each of the said ferromagnetic containers comprises a cylindrical shell closed at one end by a flanged base member and having a frustoconical outwardly projecting wall at the other end, the tip of the frustoconical wall having a groove therein through which the elongate member passes and to which the core of the coil extends, the said shell being located in a bore in a side wall of the said channel and the flange on the flanged base member abutting a reference outer face of the said side wall of the channel.

Claim 23

A transducer as claimed in claim 14, wherein there is a further first cap-pointed setscrew which is screw threadedly engaged with the frame member, has its points arranged to bear against one of the first metal blocks on the side thereof remote from the side thereof which is in contact with the elongate member, and has its axis lying in a plane containing the elongate member, and there is a further second cap-pointed setscrew which is screw threadedly engaged with the frame member, has its point arranged to bear against the said one third metal block on the side thereof remote from the side thereof which is in contact with the said one pair of roller members, and has its axis lying along a line which passes between the axes of the said one pair of roller members and between the axes of the other pair of roller members, the axes of the two second cap-pointed setscrews lying in a plane to which the axis of the elongate member is perpendicular and the points of contact of the two second cap-pointed setscrews with the said one third metal block being equidistant from any point on the axis of the elongate member within the said other portion of the elongate member.

Claim 24

A transducer as claimed in claim 14, wherein the elongate member and the frame member are housed in an evacuated chamber.

Claim 25

A transducer as claimed in claim 14, wherein the frame member is of a material having a coefficient of thermal expansion which compensates for thermal variations in the elongate member.

Claim 26

A transducer as claimed in claim 18, wherein the separations between the respective rollers of each of the said pairs of rollErs are substantially equal and sufficiently small to prevent flexure of the said other portion of the elongate member.