Abstract:
A base assembly (25) for a machine tool includes a support arrangement between a metal base (26) and a granite worktable (10) which eliminates distortion caused by differential thermal expansion and contraction and which isolates the base from deformation due to the weight of a workpiece. The support arrangement preferably includes three spaced-apart blocks (34, 36, 38) each with a V-groove (40, 42, 44) attached to the bottom of the granite worktable. The axes of the V-groove tracks intersect at a common point (46). The metal base includes three spherical projections located for engagement in each of the V-groove tracks. The support arrangement permits the granite worktable and the base to expand, contract and distort separately, while providing vertical support and lateral and rotational restraint. Several configurations of tracks and projections are disclosed.
Abstract:
In a coordinate measuring machine (10), apparatus for compensating the sensing means for determining the position of a probe (18) for changes in temperature, where the machine base and the support column (44) for the probe have differing coefficients of thermal expansion. In a preferred embodiment, the apparatus of this invention is used to prevent ''zero shift'' in the Z-direction for a Z-rail (30). The compensating apparatus is associated either with the support column or Z-rail (30). The apparatus offsets the greater expansion of the machine component having the greater coefficient of thermal expansion. Typically, the position sensing means for the Z-rail includes an encoder (38) and a scale (36). One element of the mount which extends upwardly from the support column has a coefficient of thermal expansion which is substantially less than that of the aluminum of which the column (44) is composed.
Abstract:
A ballbar socket head (302) is attached to a standard tool head (304) for a CNC machine tool or like device. The socket head can then be parked on the machine tool's tool chain (316) and selectively loaded into the machine tool's spindle (318) under program control by an automatic tool change arm (320). The ballbar socket head (302) is then engaged with a telescopic ballbar attached to a base socket (308). The ballbar and base socket (308) may be peripherally located on the machine's table (310), or automatically placed on the table for test purpose by the machine tool. The ballbar test function may be automatically performed during loading and unloading of the machine, in between production runs, at downtimes, or at periodic predetermined time intervals. When the ballbar equipment is loaded, the machine tool automatically follows a predetermined controlled-motion pattern for a ballbar test. After the test, the ballbar socket head (302) is returned to the machine's tool chain (316) and the ballbar, and the base unit bar and and ballbar are moved, if appropriate. The results of the test are received by a computer and may be displayed for the operator, stored for statistical analysis, or used dynamically to recalibrate the machine's motion control. Preferably, the ballbar sensor (314) communicates with the computer using wireless methods.
Abstract:
A coordinate measuring machine having a vertically movable probe shaft in which a vertical fine feed and lock mechanism for the probe shaft is provided by a first knob coupled to a magnet movable between two positions, one of said positions operatively coupling a second knob to the' probe shaft for driving said probe shaft in a vertical direction, the other of said positions being ineffective for moving the fine feed mechanism. The fine feed is accomplished throught the rotation of a second knob which is in frictional engagement through a driven quasi "V" shaped flanged wheel with the probe shaft to be moved vertically.
Abstract:
A computer interface device (56) for a coordinate measuring machine (20) comprises a trackball (78) that transmits perpendicular movement signals to a computer (60) in response to corresponding perpendicular movement (80, 82) of the trackball (78). The computer (60) is interconnected with the coordinate measuring machine (20) and normally receives measurement data corresponding to a location of a probe (52) on the computer (60). The trackball (78) is located adjacent the probe (52) so that a user grasping the probe (52) can manipulate the trackball (78) to transmit data manipulation signals to the computer. Typically, the trackball (78) moves a cursor about the computer screen (129). A plurality of data entry buttons (84, 86) are included on the interface device (56) and enable the user to execute computer procedures selected by the cursor.
Abstract:
A mechanical device (50) for surveying an area (2) and for subsequently replicating the surveyed area (2) comprises a base structure (53) and means (54) for taking a plurality of polar co-ordinate measurements relative to a central datum point (59) on the base structure (53). The base structure (53) is mounted on friction pads (56) so as not to be easily displaced from a surface to which the device is applied. The means (54) comprise counters (125 and 135) which display angular and distance measurements respectively. The counters are driven by relative rotation between the base structure (53) and structure (57 or 58) superimposed thereon.
Abstract:
A coordinate-measuring machine comprises a base (1), a portal (3), a transverse rigid element (13) connected to the posts (4, 5) of the portal, a mechanism (14) for moving the portal (3), interacting with the element (13), a system for measuring the movement of the portal (3), provided with a measuring scale (8) and with a measuring head (10) connected to the element (13), as well as a post (7) for placing the system for measuring the movement of the portal (3), mounted on the base (1) at an equal distance from the posts (4, 5) of the portal (3). The scale (8) is mounted on the post (7) in such a way that the longitudinal axis of the scale (8) passes through the measuring zone embraced by the portal (3).