GB2100879A - Mensuration stages and the like - Google Patents

Abstract

A mensuration stage for improved coupling of a sampling platform to a base plate, the coupling comprising a one piece coupling bridge having two sets of ball bearing races disposed along opposed inside edges for coupling the sampling platform to the base plate in parallel planar relationship and for permitting congruent positioning of the sampling platform with respect to the base plate. <IMAGE>

Description

SPECIFICATION Mensuration stages and the like The present invention is concerned with improvements in or relating to mensuration stages and the like.

Prior art mensuration stages include U.S.

Patent No. 4,189,953 issued to the inventor named herein on February 26, 1980, which is incorporated by reference as if fully set forth herein. The referenced patent teaches a drive system comprising drive bars each having a tapered longitudinal edge movably mounted to the sample platform and base plate of a mensuration stage. The tapered edges of the drive bars each frictionally engage a v-grooved drive wheel, each of which drive wheels being axially mounted to an intermediate plate of the stage and co-axially coupled to rotatably operable controls. Rotation of one of the controls drives only the platform along one axis and rotation of the other control drives the intermediate plate which is coupled to the sample platform along the other axis.Leaf springs formed in the ends of the drive bars urge the tapered edge of the drive bars into the groove of the drive wheel, thus enhancing the frictional engagementtherebetween. In addition, each end of the tapered edges of the drive bars is shaped to cause the drive bar to disengage frictionally from the drive wheel as the sample platform is driven to its limit in either direction along either axis.

It should be noted that the coupling between the sample platform and the base plate of the prior art mensuration stage described above is provided by an intermediate plate having v-grooved ball bearing race assemblies referenced, for example, at 210 and 211 in Figure 3 of the abovementioned U.S. patent. The intermediate plate also provides the mount for the v-grooved drive wheels and related manually operable controls.

The intermediate plate added thickness to the mensuration stage in addition to weight and added cost.

The present invention provides a mensuration stage comprising a base plate having races disposed along opposite and parallel outside edges thereof; a sampling platform having races disposed along opposite and parallel outside edges thereof; a coupling bridge having races disposed along opposite and parallel inside edges in one plane thereof and having races disposed along opposite and parallel inside edges in a second plane thereof; and a plurality of ball bearings disposed within the containment formed by the assembly of the base plate and sampling platform with the coupling bridge for the smooth relative movement of the sampling platform and the coupling bridge with the base plate.

A mensuration stage as set forth in the last preceding paragraph may further comprise a first drive wheel having a grooved tread axially mounted on the coupling bridge; a first drive bar movably mounted to the sampling platform in the first axis of movement of the sampling platform having a tapered longitudinal edge for frictionally engaging the grooved tread of the first drive wheel; and first manually rotatable control means axially coupled to the first drive wheel for linearly translating the first drive bar in response to rotational torque applied thereto.

A mensuration stage as set forth in the last preceding paragraph but one may further comprise a second drive wheel having a grooved tread co-axially mounted with the first drive wheel to the coupling bridge; a second drive bar movably mounted to the base plate parallel to a second axis of movement of the sampling platform having a tapered longitudinal edge for frictionally engaging the grooved tread of the second drive wheel; and second manually rotatable control means coaxially coupled to the second drive wheel with the first control means and first drive wheel for linearly translating the sampling platform, coupling bridge, first and second drive wheels and first and second manually rotatable control means along the second drive bar in response to rotational torque applied to said second control means.

In a mensuration stage as set forth in either one of the last two immediately preceding paragraphs, it is preferred that leaf springs are formed in each of the first and second drive bars; mounting means for mounting said first and second drive bars to said sample platform and base plate, respectively, include hold-down means for movably affixing the drive bar to its respective sampling platform or base plate, and means for adjusting the force applied to the leaf springs formed in each end of said first and second drive bars.

In a mensuration stage as set forth in the last preceding paragraph but three, it is preferred that the sampling platform moves with respect to the coupling bridge in its first axis of movement and is stationary with respect to the coupling bridge when the sampling platform is translating in its second axis of movement.

In a mensuration stage as set forth in the last preceding paragraph but one, it is preferred that the means for adjusting force on the leaf springs is a cam.

In a mensuration stage as set forth in the last preceding paragraph but five, it is preferred that the races are v-grooved and include aligners for applying compression force to the ball bearings.

In a mensuration stage as set forth in the last preceding paragraph, it is preferred that the aligners have greater radii of curvature than the ball bearings.

In accordance with the preferred embodiment of the present invention, coupling of the sample platform to the base plate is provided by a onepiece coupling bridge having two sets of v-groove bail bearing races disposed along opposed inside edges thereof for movably coupling the sample platform to the base plate in parallel planar relationship. The coupling bridge of the present invention permits congruent positioning of the sample platform with respect to the base plate.

The sample platform, also having a v-groove ball bearing races along edges corresponding to one set of races in the coupling bridge, rides ball bearings contained within the opposed v-groove races in one plane of the bridge for the first axis of movement of the stage. The assembly of the sample platform and coupling bridge rides on a second set of ball bearings contained within opposed v-groove races in the second plane of the bridge for the second axis of movement transverse to the first axis of movement. The coupling bridge also provides mount for the v-groove drive wheels and related manually operable controls.

There now follows a detailed description which is to be read with reference to the accompanying drawings of a mensuration stage according to the present invention; it is to be clearly understood that this mensuration stage has been selected for description to illustrate the invention by way of example and not by way of limitation.

In the accompanying drawings: Figure 1 is a bottom perspective view of a mensuration stage having a coupling bridge constructed according to the preferred embodiment of the present invention; Figure 2 is a side view of the coupling bridge used in the mensuration stage of Figure 1; Figure 3 is a bottom view of the coupling bridge of Figure 2; Figure 4 is a bottom view of the mensuration stage of Figure 1; Figure 5 is a side view of the mensuration stage of Figure 1; and Figure 6 is an enlarged view of the double v-groove channel formed by v-groove races in the coupling bridge and base plate of the mensuration stage of Figure 1, showing details of the ball bearing assembly therein.

Referring to Figure 1, a base plate 12 is fixedly mounted to the frame of a microscope or other device which utilizes a mensuration stage. Such mounting is not shown in order to more clearly illustrate the present invention. A sampling platform 10 is coupled to the base plate 12 by a coupling bridge 11. The coupling bridge 11 preferably comprises one piece having v-groove ball bearing races 21 disposed along opposed inside edges 31 thereof. The races 21 are located along the edges 31 such that similar v-groove races 27, disposed along outside edges 23 and 25 of the sample platform 10 and the base plate 12, respectively, form a containment for ball bearings 22. Thus, the platform 10 rides on the coupling bridge 11 and the coupling bridge 11 rides on the base plate 12, respectively, on ball bearings 22.

In one embodiment, drive bars 13 may be movably mounted to the sample platform 10 and the base plate 12 by mounting hardware 1 8. The mounting hardware 18 comprises a hold down 28 and a cam 29, each mounted by machine screws.

As the cam 29 is rotated, tension on leaf spring portions 14 of each drive bar is adjusted.

The drive bars 13 also may be mounted to the sample platform 10 and the base plate 12 by mounting hardware 17, which is similar to mounting hardware 220 and 221 of the abovementioned U.S. patent. It should be noted that mounting hardware 18 or 1 9 may be used for mounting both drive bars 13, provided, however, that more clearance is necessary between the coupling bridge 11 and the drive bars 13 if mounting hardware 1 9 is used.

As the top view of Figure 3 shows, the coupling bridge 11 is frame-like in aDpearance. The v-groove races 21 are disposed along opposed and parallel inside edges 31 of the bridge 11 for accepting the ball bearinas 22. Similarly, the v-groove races 27 are provided along the outside edges 23 of the sampling platform 10 and outside edges 25 of the base plate 1 2 for accepting the ball bearings 22. Thus, when the base plate 12 is assembled with the coupling bridge 11 as shown in Figure 5, the ball bearings 22 are contained in the double v-groove channels formed by the v-groove races 21 and 27.

Rotation of a manual control 1 6 applies rotational torque to a drive wheel (not shown) coupled to the drive bar 1 3 which linearly translates the sampling platform 10 in either direction along an axis 40. Rotation of another manual control 1 5 applies rotational torque to a drive wheel 30 coupled to a second drive bar 13 which linearly translates the coupling bridge 11 in either direction along an axis 41. Since the sampling platform 10 is coupled to the bridge 11 by the ball bearing race assemblies described above, the sampling platform 10 is thereby translated also in either direction along the axis 41.

Referring now to Figure 6, the ball bearings 22 are compressed in the v-groove races by aligners 24 to assure that all balls track uniformly in the v-groove and with respect to each other, thus providing smooth relative movement of the sampling platform 10, base plate 12, and coupling bridge 11. The pre-load compression applied to the ball bearings 22 is also effective for reducing wobble and backlash in movement of the stage.

The aligners 24 extend substantially the entire length of each v-groove, are constructed of hardened sheet steel and have greater radii of curvature than the balls for developing the desired compression force. A collet 26 merely checks movement of several ball bearings with respect to one another in the longitudinal axes of the aligners 24.

The v-grooved drive wheels, manual controls 15 and 16, and drive bars 13 may be similar to those also described in the above-mentioned U.S.

patent. The leaf springs 14 formed in the ends of the drive bars 13 are deflected to provide urging force between the drive bars and their respective v-grooved drive wheels. Adjustment of the deflection of the leaf spring is provided by the cam 29 of the mounting hardware 1 8 as described above.

Stops are provided to terminate the travel of the sampling platform 10 and the coupling bridge 11 in the same manner as that described in the above-mentioned U.S. patent. As the moving sampling platform 10 or coupling bridge 11 engages a stop, the associated drive bars 1 3 frictionally disengage from the corresponding drive wheel as additional torque is applied in the same manner as that disclosed in the abovementioned U.S. patent.

Claims (9)

1. A mensuration stage comprising: a base plate having races disposed along opposite and parallel outside edges thereof; a sampling platform having races disposed along opposite and parallel outside edges thereof; a coupling bridge having races disposed along opposite and parallel inside edges in one plane thereof and having races disposed along opposite and parallel inside edges in a second plane thereof; and a plurality of ball bearings disposed within the containment formed by the assembly of the base plate and sampling platform with the coupling bridge for the smooth relative movement of the sampling platform and the coupling bridge with the base plate.

2. A mensuration stage according to claim 1 further comprising: a first drive wheel having a grooved tread axially mounted on the coupling bridge; a first drive bar movably mounted to the sampling platform in the first axis of movement of the sampling platform having a tapered longitudinal edge for frictionally engaging the grooved tread of the first drive wheel; and first manually rotatable control means axially coupled to the first drive wheel for linearly translating the first drive bar in response to rotational torque applied thereto.

3. A mensuration stage according to claim 1 further comprising: a second drive wheel having a grooved tread co-axially mounted with the first drive wheel to the coupling bridge; a second drive bar movably mounted to the base plate parallel to a second axis of movement of the sampling platform having a tapered longitudinal edge for frictionally engaging the grooved tread of the second drive wheel; and second manually rotatable control means coaxially coupled to the second drive wheel with the first control means and first drive wheel for linearly translating the sampling platform, coupling bridge, first and second drive wheels and first and second manually rotatable control means along the second drive bar in response to rotational torque applied to said second control means.

4. A mensuration stage according to either one of claims 2 and 3 wherein: leaf springs are formed in each end of the first and second drive bars; mounting means for mounting said first and second drive bars to said sample platform and base plate, respectively, include hold-down means for movably affixing the drive bar to its respective sampling platform or base plate, and means for adjusting the force applied to the leaf springs formed in each end of the said first and second drive bars.

5. A mensuration stage according to claim 1 wherein the sampling platform moves with respect to the coupling bridge in its first axis of movement and is stationary with respect to the coupling bridge when the sampling platform is translating in its second axis of movement.

6. A mensuration stage according to claim 4 wherein the means for adjusting force on the leaf springs is a cam.

7. A mensuration stage according to claim 1 wherein the races are v-grooved and include aligners for applying compression force to the ball bearings.

8. A mensuration stage according to claim 7 wherein the aligners have greater radii of curvature than the ball bearings.

9. A mensuration stage substantially as hereinbefore described with reference to the accompanying drawings.