HIGH SENSITIVITY ACCELEROMETER

• US 3,691,850 A
• Filed: 02/24/1970
• Issued: 09/19/1972
• Est. Priority Date: 02/24/1970
• Status: Expired due to Term

• Current Assignee: Doyle E. Wilcox, John M. Slater
• Original Assignee: Doyle E. Wilcox, John M. Slater
• Inventors: Slater, John M., Wilcox, Doyle E.
• Primary Examiner(s): Gill, James J.
• Application Number:
  US05/015,971
• Time in Patent Office: 938 Days
• Field of Search: 73/515,516
• US Class Current: 73/514.06
• CPC Class Codes: G01P 15/132 with electromagnetic counterbalancing means

Abstract

A accelerometer for extraterrestrial craft which can be tested on earth by being isolated from gravity is constructed having a movable proof mass member which is either a hollow metalized conductor loop suspended by filaments, or a hollow sphere of ferromagnetic material. In either case, the net density of the proof mass member is such as to permit substantially complete flotation of the proof mass in water maintained at the temperature of maximum density. The proof mass is then immersed in the water so as to attenuate gravity to any desired degree. The instrument may then be tested in known ways in the laboratory, and the water removed before the accelerometer goes into service in the craft. The invention herein described was made in the course of or under a contract or subcontract thereunder, with the Air Force.

Claims

1. The method of producing an accelerometer for responding to small acceleration produced forces, which method comprises the following steps:

providing a proof mass member and means for detecting displacement of the member;

suspending said proof mass member for said accelerometer in an aqueous solution providing a substantially neutral buoyant support to said proof mass in an environment of approximately 1-g; and

removing said solution from about said proof mass member to free said proof mass member to respond to acceleration produced forces applied to said accelerometer in an environment of substantially less than 1-g.

2. The method of claim 1 in which said proof mass member has a mass exceeding the linear range of said detecting means for the accelerometer and said fluid provides a substantial amount of isolation of said proof mass from gravity in approximately a one-g environment.

3. The method of claim 1 in which the proof mass member is suspended in an aqueous solution and the temperature is adjusted to produce a solution density which is substantially the same density as the proof mass member but not equal to the density of the proof mass member.

4. The method of claim 1 in which said aqueous solution is a mixture of H20 and D20.

5. The method of claim 1 in which the buoyant support provided is substantially complete flotation for said proof mass member.

6. The method of claim 1 in which the relative densities of said mass member and solution are adjusted to enable the accelerator to be tested for small accelerations in approximately a 1-g environment.

7. The method of providing an accelerometer capable of responding to very small acceleration produced forces of less than 10 3 g which method comprises the following steps:

providing an accelerometer with a proof mass member and force sensing means in which the proof mass member total mass exceeds the linear range of the force sensing means in approximately a 1-g environment;

disposing said proof mass in an aqueous solution to produce substantial buoyant support thereof and thereby isolate said proof mass from the 1-g environment to the extent required to maintain operation in the linear range of said force-sensing means; and

removing said aqueous solution to decrease the buoyant support of said proof mass member for operation of said accelerator in an environment substantially less than said 1-g environment.