CA2380561A1 - Vernier caliper jaw brackets - Google Patents

Abstract

A pair of attachment brackets coupled to the first and second measurement jaws of a handheld vernier caliper. A first bracket couples a first caliper jaw to a linearly moving component within a machining apparatus such as a lathe or milling machine. A
second bracket couples the second caliper jaw to a stationary component within said apparatus, thereby enabling the caliper to accurately track and measure relative distance between the two machine components. Each attachment bracket includes a first magnetic or mechanical clamping means for orthogonally gripping onto a caliper jaw. Each bracket further includes a second magnetic or mechanical clamping means for orthogonally gripping onto a stationary or moving component within the machining apparatus.
Another embodiment includes a first bracket that orthogonally mates a first jaw of a first caliper to a horizontal reference tablet and a second bracket that converts the caliper's second jaw into a touch probe, thereby enabling the caliper to measure Z
coordinates on an object. Another embodiment includes second and third pairs of brackets that attach second and third calipers to the reference tablet such that the touch probe can also measure X and Y coordinates on the object.

Description

VERNIER CALIPER JAW BRACKETS
A pair of attachment brackets coupled to the first and second measurement jaws of a handheld vernier caliper. A first bracket couples a first caliper jaw to a linearly mg component within a machining apparatus such as a lathe or milling mach' .
second bracket couples the second caliper jaw to a stationary component w' said apparatus, thereby enabling the caliper to accurately track and measure r me distance between the two machine components. Each attachment bracket in es a first magnetic or mechanical clamping means for orthogonally gri ' g onto a caliper jaw. Each bracket further includes a second magnetic or mec ical clamping means for orthogonally gripping onto a stationary or movin mponent within the machining apparatus.
Another embodiment include st bracket that orthogonally mates a first jaw of a first caliper to a horizontal r ence tablet and a second bracket that converts the caliper's second jaw into a ch probe, thereby enabling the caliper to measure Z
coordinates on an object. er embodiment includes second and third pairs of brackets that attach seco d third calipers to the reference tablet such that the touch probe can also BACKGROUND
Handheld vernier calipers are commonly used by machinists to measure the dimensions of their workpiece as it progresses through fabrication processes on a lathe, milling-machine or similar machining apparatus. In order to machine the work piece to the desired dimensions, caliper measurements are periodically made and used to guide motion of the machine's toolbit. Tool carriages riding on linear rails permit precise cutting control along the machine's orthogonal axes. The linear motion of each tool carriage is typically actuated by a crank-wheel and drive screw mechanism.
Angular graduations around each crank-wheel are used to measure changes in the distance to the tool carriage as it travels along its guide rail.
Using graduated crank-wheels to measure distance traveled is simple and inexpensive however the crank's dial markings are not easy to read and interpret.
Furthermore, backlash in the screw actuator causes measurement errors. To address this problem, some machine tools have digital linear motion encoders built into their tool carriages and guide rails, thereby providing a more accurate and easily understood measurement display.
Unfortunately, integrating digital encoders and displays into a machine tool adds significantly its cost. To address this problem, Novak (US 6,009,633) devised a caliper jig that affixes the machinist's handheld vernier caliper to components of the machining apparatus in a manner that converts the caliper into a low-cost and accurate motion encoder.
Novak's invention supers from several drawbacks. In order to transmit relative motion from the machine tool's components to the caliper's measurement mechanism, Novak's device requires a complex array of pulleys, a biasing spring, pins, screws, bushings, gripping jaws, slides, guide ways, housing parts and magnets. Each of these components adds to the cost of the device and, depending on their quality of construction, may add friction and imprecision to the overall measurement system. Furthermore, Novak's device utilizes the caliper's fragile tailpiece to abut against one of the machine's components. Novak's device is also limited to measuring relative motion between two orthogonal surfaces whereas many operational scenarios require measuring relative motion between coplanar surfaces.
It is therefore an object of the present invention to provide a means of transmitting motion from the machine components to the caliper that eliminates all of the disadvantages noted in the prior art.
It is a further objective of the present invention to extend its inventive concept beyond simply measuring the relative distance between orthogonal components of a machining apparatus. More specifically, an embodiment of the caliper jaw brackets is configured to convert the caliper into an instrument for measuring the height (Z) of points on an object with respect to a precise reference surface. Furthermore, an embodiment of the caliper jaw brackets is configured to attach additional calipers to the reference surface in a manner that forms an apparatus capable of measuring the three-dimensional coordinates of points on an object.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of an embodiment of the caliper brackets, said brackets affixing one of the caliper's jaws to a moving surface and its other jaw to a stationary surface, said surfaces being orthogonal within the machining apparatus.
FIG. 2 is a partially, exploded view of the vernier caliper and jaw bracket assemblies shown in FIG. 1.
FIG. 3 is an alternate embodiment of the jaw brackets having fixed magnets.
FIG. 4 is a perspective view of an embodiment of the caliper brackets affixed to a drill press.
FIG. 5 is a large-scale view of FIG. 4 FIG. 6 is a perspective view of an embodiment of the caliper brackets, said brackets affixing one of the caliper's jaws to a moving surface and its other jaw to a stationary surface said surfaces being coplanar within the machining apparatus.
FIG. 7 is a partial view of the jaw bracket assemblies shown in FIG. 6.
FIG. 8 is a perspective view of caliper jaw brackets, said brackets being configured to convert the caliper to act as a height gauge.
z FIG. 9 is a larger-scale view of FIG. 8, shown from a different perspective and including alternate measurement probes.
FIG. 10 is a perspective view of the height gauge assembly shown in FIG. 8 and further comprising two additional caliper and bracket assemblies configured to convert the height gauge into a 3D coordinate measuring machine.
DETAILED DESCRIPTION
Referring to FIG. 1 and FIG. 2: mobile tool carriage 1 moves along guide rail 2 within a machining apparatus. A generic tool carriage is shown that would typically also include provisions for holding a lathe tool bit (in the case of a rotating work piece) or a milling machine vice (in the case of a rotating tool bit).
Handheld vernier caliper assembly 5 is comprised of -fixed measurement jaw 3 coupled to a sliding measurement jaw 4. Sliding measurement jaw 4 includes display unit 6, which senses and displays the relative motion and distance between opposing faces of the caliper's two measurement jaws 3 and 4. The moving and fixed caliper jaws typically include a large jaw portion used to measure outside dimensions (hidden inside brackets 7 and 8) and a smaller jaw portion, which is used to measure inside dimensions.
Display unit 6 may be a vernier, a mechanical dial gauge or the digital electronic sensor as illustrated. Buttons are typically provided for zeroing the digital readout at any jaw opening, freezing the display, converting between metric and imperial units or similar electronic control functions.
In the machining apparatus illustrated in FIG. 1 and FIG. 2, tool carriage 1 and carriage guide rail 2 present flat surfaces that remain orthogonal as the carriage moves along the rail. To effect the desired instrumentation, first jaw bracket body 7 is fitted over and affixed to the large portion of mobile caliper jaw 4 and second jaw bracket body 8 is fitted over and affixed to the large portion of fixed caliper jaw 3.
The outer shape of bracket body 7 and 8 forms an orthogonal block of sufficient dimensions that, when both of said brackets are affixed to caliper 5, the back of the caliper assembly is raised clear of carriage guide rail 2. Bracket bodies 7 and 8 are typically formed from a magnetically attractable material such as mild steel.
The embodiments illustrated in figures 1, 2, 4 and 5 receive a caliper jaw 3 or 4 in slot 31 formed within each bracket body. Bracket body 7 and bracket body 8 each include an orthogonal alignment edge 32 that mates against the opposing measurement edges of jaw 3 and jaw 4. In the simpler embodiment illustrated in FIG 3, one side of each caliper jaw is affixed to an external surface of the bracket body and the jaw's measurement edge is mated orthogonally against, a raised alignment edge 32 projecting from the bracket.
Each caliper jaw bracket includes means for affixing it to a caliper jaw. FIG.
2 illustrates one such means. One or more threaded setscrew bores 13 pierces the upper surface of said body to receive setscrew 14. An end of setscrew 14 is tightened through bore 13 onto the side of caliper jaw 2 or caliper jaw 3, thereby orthogonally affixing the six outer surfaces of each bracket with respect to its caliper jaw's measurement edge.
Setscrews 14 provide a very solid fixation means however adjusting them lengthens the time taken to convert a caliper between handheld and affixed modes. FIG. 3 illustrates a faster means for affixing a bracket body to its respective caliper jaw. In the illustrated, embodiment, one or more magnets 12 are embedded flush to various outer surfaces of bracket 7 and 8. Single disk magnets are illustrated however rectangular magnets or multiple disk magnets may also be used to magnetize the attachment surface.
Magnet 12 is located in close proximity to alignment edge 32, thereby providing a magnetic means for orthogonally gripping the side of a caliper jaw. This magnetic fixation means is only eiTective on caliper jaws made of magnetically attractable material. If the caliper jaws are not magnetically attractable, then the clamping embodiment described above may be used. An alternate non-magnetic clamping embodiment (not illustrated) utilizes spring-loaded clamping contacts inside slot 31 (in place of setscrews), thereby providing a faster mechanical means for affixing or removing the bracket.
The present invention also uses magnetic attraction to affix caliper jaw brackets 7 and 8 to components of the machine tool being instrumented. Referring to Figures 1 through 5, one or more magnets 12 are positioned between a surface on bracket body 7 and tool carriage guide rail 2, thereby affixing bracket 7 and caliper jaw 4 to the rail. Similarly, other magnets 12 are used to magnetically affix bracket 8 and caliper jaw 3 to mobile tool carriage 1.
FIG. 4 and FIG. 5 illustrate the simplest embodiment of the magnetic attachment means in which the outer surfaces of bracket bodies 7 and 8 are flat. Magnets 12 are affixed anywhere on the outer surfaces of each bracket, thereby permitting attachment of the caliper jaws to the machine tool. Three of each jaw bracket's six sides are traversed by slot 31; therefore a sufficiently large magnet 12 is used to provide stability by spanning slot 31. Rare earth disk magnets measuring 0.5" X .125" are a commonly available and work with a wide variety of calipers and machine configurations. Magnets 12 can be easily moved laterally on the flat sides of bracket 7 and 8 or redeployed to different bracket sides to accommodate different machine tool configurations.
The drill press configuration illustrated in Figures 4 and 5 is comprised of a cylindrical tool carriage 1 that moves with respect to an orthogonal surface on frame 2.
This configuration is shared by other machine tools such as chucks on milling machines or tailstock chucks on lathes. Vernier jaws 3 and 4 are shown attached to the drill press' cylindrical barrel l and its main frame 2 however other attachment scenarios are possible.
For example, many drill presses have a mechanical depth stop flanges, which present parallel surfaces suitable for affixing jaw brackets.
Each machine tool has its own unique configuration that the user must analyze to find a mounting site that provides visibility to the vernier display, clearance for the brackets and orthogonal alignment for the magnetic contact points. Exposed bolts or gaskets on the machine may also impede optimal mounting. In such cases, the user may utilize stacked magnets to act as shims in order to provide adequate bracket positioning with respect to the direction of tool motion. Not all possible machine tool configurations have been illustrated here. However, a competent machinist will be able to utilize the versatility inherent to different permutations of magnet positions and jaw bracket orientations to effectively affix a caliper to all tool configurations commonly encountered in a machine shop.
The illustrated embodiments of the jaw brackets are adaptable to a wide variety of machine tools. However, certain makes and models of machine tools may have components made of non-magnetic material such as aluminum, and therefore not suitable for use with the present invention. C)ther machines may have cosmetic features or functional protrusions on their moving components that impede orthogonal mounting of brackets 7 and 8 and that cannot be compensated for by simply shimming the magnets.
Therefore, in such cases, custom formed steel brackets may be provided that are affixed to the machine using adhesive or screws. These custom adaptor plates (not illustrated) modify a particular machine component such that a suitable magnetic mounting surface is presented to bracket 7 or 8.
The jaw bracket clamping means disclosed above may also be incorporated directly into the machine tool's components during their manufacture (not illustrated).
The flat-sided jaw bracket bodies shown in FIG. 4 and FIG. 5 have the advantage of being easily reconfigured to fit different machine tools as well as being simple to manufacture. However, the contact area between bracket magnets 12 and the machine's moving components is relatively small, thereby increasing the possibility of slippage during use. The jaw bracket embodiment shown in FIC'r. 2 provides greater contact area between the jaw bracket and machine tool surface as well as preventing side movement of the magnets. Magnet sockets 9 permit magnet 12 to lie flush with the bracket's contact surface. The depth of magnet socket 9 may be equal to the thickness of magnet 12 as shown. Shallower magnet sockets 10 may also be used if only lateral stabilization of the magnets is required.
Slot 31 receives a caliper jaw however it also serves to facilitate removal of magnet 12 by permitting the user to insert a knife or similar instrument to pry the magnet from its socket 10. In the case of magnets held flush within the deeper sockets 9, a keyway 33 machined between adjacent sockets facilitates magnet removal. By permitting easy removal of magnetl2 from magnet sockets 9 and 10, a single shape of bracket body can be reconfigured to act as either bracket 7 or bracket 8.
FIG. 3 illustrates magnets that are permanently embedded flush to the bracket's mating surfaces. This embodiment requires additional magnets however it permits the bracket body to a made of non-magnetic material such as aluminum or plastic.
FIG. 6 and FIG. 7 illustrate a common machine tool configuration: the moving, tool carrying component's surface 2 and the stationary component's surface 1 are coplanar.
Since brackets 7 and 8 must be affixed to only one or the other of these two surfaces, the brackets require asymmetric adaptations in order to correctly affix caliper 3 and 4 to the machine components. Magnetic side flange 15 is affixed to the side of bracket 7 and 8, oriented such that its magnetic surface is at right angles to the caliper jaw's measurement edge. In order to maximize contact area of side flange 15, one or more magnets 11 are received flush, each within a magnet socket 17. To increase the versatility of brackets 7 and 8, screws 16 may be used to selectively affix side flanges 15 to an upper or lower location, thereby permitting the bracket to be configured to fit the widest variety of machine tool.
FIG. 8 and FIG. 9 illustrate an embodiment of the invention that converts vernier caliper into a height gauge capable of measuring the vertical height of points on an object above a horizontal datum surface. Datum block 18 is typically machined out of granite or similar stable material and has surfaces that are precisely flat and orthogonal. Object 21 is an arbitrarily shaped work piece having discrete upper surfaces whose relative heights need to be measured.
Caliper carriage 19 is a flat planar member that can be hand guided in any direction over horizontal reference surface 18. Bracket body 26 projects from the upper surface of vernier carriage 19 and incorporates the same magnetic or mechanical clamping means described above (i.e. magnets gripping a side of jaw 3 or a slot and set screws gripping both sides of jaw 3). The upper surface of carriage 19 also forms alignment edge 31 where is abuts against the orthogonal end of jaw 3. The surfaces of carriage 19 and bracket body 26 are precisely orthogonal, thereby holding the measurement axis of caliper 5 at right angles to the top surface of datum block 18.
In order for the bottom (measurement) surface of caliper jaw 4 to contact points on the top of object 21, extension bracket 22 is affixed to it. Extension bracket 22 is comprised of an elongated structural portion, a precisely aligned measurement contact portion and a fixation pans portion. The fixation means portion may include either magnetic or mechanical clamping means as disclosed above. In FIG. 8, fixation screw 23 bears onto the upper surface of jaw 4, thereby affixing bracket 22 to the jaw and insuring precise mating along alignment edge 32. Alignment edge 32 is parallel to the extension bracket's lower surface; thereby insuring that changes in height observed by contacting points on the extension bracket to points on the top of object 21 will be accurately reflected on distance readout 6.
Since the upper (measurement) edge of jaw 3 is located an unknown distance above datum surface 18, a gauge block 20 of known height may be provided to calibrate height display 6. For example, if the gauge block is exactly 1 inch high, the lower surface of extension bracket 22 is lowered until it contacts the gauge block and display 6 is initialized to zero. In order to measure the object's absolute height, one inch is then added to subsequent readings observed when the extension bracket is in contact with its top edge.
Physical features located inside of object 21 cannot be contacted by the straight bottom edge of extension bracket 22. Therefore vertical probe 24 may be affixed to extension bracket 22 to provide a ~asurement contact point capable of being lowered inside the object. Probe 24 may be axed to bracket 22 by means of suitable threaded holes, spring clamps or magnetic fixations (not illustrated). Typically, probe 24 will be long enough that gauge block 20 can be eliminated and display 6 can be zeroed when the probe's tip is touching datum surface 18.
FIG. 9 illustrates several embodiments of probe 24. Pointed probe 24b and rounded probe 24c are used as described above to make height measurements inside of object 21.
Pointed probe 24d is mounted horizontally, thereby enabling the height of multiple points at different elevations on the sides of object 21 to be measured. Probe 24a is a hybrid probe having a vertical portion and a horizontal portion that provides access to points inside object 21.
Since caliper assembly 5 was not designed for use in conjunction with a cantilevered probe, a certain degree of flexibility is inherent to the total assembly. To maintain accuracy, the caliper readings must therefore be made at the instant probe 24 gently makes contact with object 21. Any forcing of the probe's contact will result in deflection of the assembly and subsequent loss of accuracy. Therefore, electrical contact sensors 25a and 25b may be provided to alert the user at the exact instant of probe contact.
Electrical wire 27 connects the two sensor components such that current flows when probe 24 closes the circuit through metal object 21. The closed circuit activates an audible buzzer and/or a visible LEIS (an internal battery and other sensor details are not illustrated). Sensors 25a and 25b may also incorporate a magnetic base to enable their fixation to the object being measured and the caliper/ carriage assembly.
Since the height of jaw 4 is manually adjusted, imparting very small and accurate height changes to it require great dexterity. To aid the operator in making such fine height adjustments, a threaded travel adjuster may be provided (not illustrated).
Vernier calipers are commonly equipped with such fine adjustment means that typically slide along and lock to the fixed vertical portion of the caliper. The adjuster then permits fine motion of the moving jaw by means of a threaded motion screw.
FIG. 10 illustrates an augmented embodiment of the height gauge assembly used fox measuring height (Z). To additionally measure horizontal coordinates, a second caliper assembly Sb is used to constrain height gauge carriage motion along an X axis as well as measuring distance changes to the height gauge assembly as it moves along that X axis.
Caliper carriage 19 includes jaw bracket 29a that incorporates mechanical or magnetic jaw fixation means similar to those described above. Alignment edge 32a is oriented at right angles to alignment edge 32b, thereby forcing orthogonaIity between height caliper Sa and X caliper Sb. Jaw to edge bracket 28a is also similar to previously described jaw brackets however it also includes an orthogonal, downward oriented flange that affixes the assembly to a side of datum block 18 (typically using adhesive). The X
distance reading of caliper Sb is zeroed when probe 24 is touching a horizontal datum (typically located at an outside corner of object 21 ), thereby enabling the user to manipulate calipers Sa and Sb and observe the X and Z coordinates of probe 24 where it touches points located on object 21.

Similarly, a third caliper assembly Sc is affixed to object carnage 30 by means of jaw bracket 29b and jaw bracket 28b, thereby constraining the motion of object 21 along a Y
axis as well as measuring distance changes to the object as it moves along that Y axis.
By manipulating calipers Sa, Sb and Sc, the user is thereby enabled to observe accurate X, Y and Z coordinates of probe 24 where it touches points located on object 21.
Known horiaontal offsets between the four horiwntally oriented points on probe 24 and the probe's vertical axis, permit the user to calibrate tla' readings of calipers Sb and Sc at a datum location an then adjust X and Y coordinate readings to compensate for contacting different probe points onto different features of object 21.
tn aoo~rer embodiment of the 3D , a nor-'rostrtuncnbod mod ar~chiOe is Mtad with 3 calipers to provide digital readouts that track motion of its 3 axes.
Attachment mesas for affocing the calipers to such a machine are desen'bed at length above. To permit the milling machine to aa. as a dig'rti~er, a poiraer such as a drill or scn'bat is held in tine milling machime's chuck. The operator rtbuea the tip of the poi~er to touch different points on the object being digitized and their XYZ coordinates are logged to create its digits! model.
This des~ioa cords much SpaciBcity that s~uld not be coasdrtred as limidmtg the scope of the invention but merely provides illustrations of some of its embodiments.
Thus the scope of tire invention should be deterrnired by the apQended c~ and their legal equivalents rather they by the examples given.

Claims (6)

1. A manually operable toothbrush comprising a straight handle and a "U" shape bristle holder on one end of the toothbrush.

2. A toothbrush as defined in claim 1 in wich in the bottom inside part of the "U"
shape bristle holder there are short bristles that are softer than the normal type U.S.A or Canadian toothbrush bristles and are between one eight of an inch long to three sixteenth of an inch long.

3. The toothbrush as defined in claim 1 and 2 in wich the two sides of the inside part of the "U" shaped bristle holder there are normal type U.S.A or Canadian bristles.
They are from three eight of an inch to seven sixteenth of an inch long. They could be made shorter but depending on how short, they might have to be softer bristles.

4. The toothbrush as defined in claim 1,2 and 3 in wich the two sides of the inside part of the "U" shaped bristle holder the bristles are shorter in the middle of the side brushes going horizontal compared to the vertical bottom bristles. That makes a hole to put toothpaste in. The hole should be three sixteenth of an inch to one quarter of an inch square.

5. The toothbrush as defined in claim 1, 2,3 and 4 in wich the side bristles at the "U"shape bristle holders would start horizontally to the vertical bottom bristle and gradually be angled up to the end. Up so that the tip of the bristles would be one eight of an inch to three sixteenth of an inch over the top of the side bristle holders.

6. The toothbrush defined in claim 1,2,3,4 and 5 in wich the handle of this invention can be made in different sizes and shapes. The "U" shaped brush can be made in different sizes. The height of the side brush holder of the "U" shaped brush would be made in different height. Add more bristles or substact some for different height.