Camtech, LLC

Macotech Corporation

Richard A Mathias

Lyle C Adams

Edward N Miller

The load measurement apparatus includes a pressure arm 60 rigidly coupled to a structural member whose load is to be measured, and a miniature instrumented hydrostatic cell rigidly mounted in proximity to the pressure arm so that a membrane of the cell engages the pressure arm and displaces as the pressure arm displaces. In one embodiment, the cell includes a housing consisting of a first cylindrical portion 20 and a second cylindrical portion 22 integral with and centrally projecting from the first cylindrical portion. A cylindrical cavity 24 is formed within the housing portions and coaxial therewith. At one end, the cavity is closed by a thin membrane 26, and at its other end, the cavity communicates with a threaded bore that receives and is closed by female portion 34 and male portion 36 of a seal. A temperature compensation insert 30 is disposed within the cavity, and the portions of the cavity not occupied by the insert are completely filled with an incompressible fluid that is introduced through the seal. The pressure within the cavity is measured by a pressure transducer 50. The cell is disposed within a cavity of a receptacle member 64 and the membrane thereof is urged into engagement with a sphere 66 embedded in the pressure arm by a pair of Belleville disc springs 72, 74 disposed within the receptacle member cavity and by an adjustment plug 78 threadably received in that cavity.

Load measurement apparatus including miniature instrumented hydrostatic

The sensor includes at least one pressure chamber that is filled with an incompressible fluid, a membrane that forms at least one wall of the pressure chamber, a pressure transducer measuring the pressure within the pressure chamber, and a pressure arm whose first end is secured to a machine tool member at a location at which force and torque are to be measured and whose second end bears on the membrane. By appropriately choosing the number and disposition of pressure chambers, membranes, and pressure arms, output signals from the corresponding pressure transducers are related to selected components of transverse force torque, and axial force of the machine tool member. Various embodiments of the sensor for use with machine tools having a rotating tool and machine tools having a stationary tool are disclosed, and techniques are described in which these embodiments can be used to determine the angle between transverse force exerted on the machine tool member and a stationary axis of the machine tool, to determine the plane of transverse loading of the transverse force, and to compensate the pressure measurements in accordance with the determined plane of transverse loading.

Force and torque sensor for machine tools

Prior art adaptive control systems for numerically-controlled milling machines are first discussed in which N/C instructions and adaptive control system data are obtained and stored in a storage medium utilizing a software routine which takes into consideration parameters of the milling process and parameters of a specific milling machine. The instructions and data command, for sequential steps in the milling process, such items as spindle position, feedrate and reference milling forces and are supplied to an N/C unit and to the adaptive control system at the milling machine to automatically control the milling process. The adaptive control system includes a milling force sensor and functions to override the commanded feedrate on comparison of the actual milling forces during the process with the reference milling forces. An improvement is then discussed which modifies the adaptive control system data so that the data can be used on any milling machine having an N/C unit capable of responding to the N/C storage medium in which the N/C instructions and adaptive control system data are stored. A set of universal adaptive control variables are included in the adaptive control data. The adaptive control system at the milling machine is modified to respond to these universal adaptive control variables and further to internally store machine constants for the specific milling machine with which the adaptive control system is utilized. The improved adaptive control system then recomputes the adaptive control data including reference milling forces in accordance with the universal adaptive control variables and the machine constants and utilizes the recomputed adaptive control system data to override where necessary the commanded feedrate. In addition, provision is made in the improved adaptive control system for further modifying the adaptive control system data by operator-entered manual process control inputs. Applications of such improved adaptive control systems to numerically-controlled machine tools other than milling machines are also discussed.

Growing community of inventors

Renton, WA, United States of America

Richard A Mathias