Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
  • G01B3/00—Measuring instruments characterised by the use of mechanical techniques
  • G01B3/20—Slide gauges

Definitions

• the invention relates to a slide gauge with a rail, a slide arranged on the rail and a driving wheel that rotates on the slide and rolls on the rail for moving the slide along the rail.
• the slide is finely adjusted during the measurement process in such a way that the drive wheel is actuated with the thumb.
• the drive wheel rolls on a longitudinal edge of the slide, and the axis of the drive wheel exerts a force acting in the longitudinal direction of the rail on the slide, so that it is displaced along the rail.
• the movement of the thumb is translated into a movement of the slide approximately in a ratio of 2: 1, so that an exact adjustment of the slide is made possible.
• the force exerted on the slide is approximately twice the force exerted by the thumb. This has the additional advantage that the frictional resistance occurring between the rail and the slide can be overcome more easily.
• the driving wheel is usually provided with a circumferential groove with conically beveled flanks, which engages with a prism-shaped ground edge of the rail. In this way there is sufficient friction between the
• Driving wheel and the tread on the rail ensures that the driving wheel does not slip.
• slide gauges made of plastic are known, in which a sufficient engagement of the driving wheel with the Rail is guaranteed by a corrugation or toothing on the circumference of the driving wheel and on the running surface of the rail.
• the drive wheel can be rotated about an axis which is stationary with respect to the slide and is therefore constantly in engagement with the running surface of the rail.
• This has the disadvantage that the force amplification caused by the translation also occurs when the measuring surfaces of the slide gauge are already in contact with the object to be measured, so that a relatively high measuring pressure results. This can lead to deformation of the material and thus to measurement errors, particularly in the case of slide gauges made of plastic.
• the invention has for its object to provide a slide gauge of the generic type in which measurement errors caused by material deformation are avoided.
• This object is achieved in that the drive wheel is provided with a ratchet mechanism to limit the force transmitted from the drive wheel to the slide.
• the force amplification brought about by the drive wheel is thus overridden as soon as the object to be measured opposes the movement of the slide and the actuating force used by the user exceeds a predetermined threshold value.
• the measuring pressure is thus limited to a permissible level at which no material deformations yet occur.
• the ratchet mechanism is preferably formed by a holder of the drive wheel, which holds a positively guided movement of the driving wheel in a direction inclined towards the longitudinal direction of the rail with respect to the slide.
• the driving wheel is held in engagement with the tread by the user's thumb.
• the force exerted by the thumb on the circumference of the drive wheel which has a large component in the longitudinal direction of the rail, causes the drive wheel to shift in the oblique guide, so that the drive wheel of the tread is lifted off.
• the inclined guide is preferably formed by two elongated holes, each of which receives one end of an axle integrally formed on the drive wheel. This design of the ratchet mechanism achieves an effective limitation of the measuring pressure with simple means.
• Fig. 1 shows a partial view of a slide gauge according to the invention
• FIG. 2 is a side view of a drive wheel of the slide caliper according to the invention.
• FIG. 3 is a partially cutaway view in the direction of arrow III in FIG. 2.
• FIG. 4 show cross and longitudinal sections of a ratchet mechanism and 5 mechanism according to another embodiment of the invention.
• Fig. 6 show cross and longitudinal sections of a modified and 7th ratchet mechanism.
• a slide gauge 10 comprises a rail 12, which is provided at one end with a longer measuring tongue 14 for tapping external dimensions and a shorter measuring tongue 16 for tapping internal dimensions.
• a slide 18 movable in the longitudinal direction on the rail 12 also has a longer measuring tongue 20 for tapping outside dimensions and a shorter measuring tongue 22 for tapping inside dimensions.
• the slide 18 is also provided with a dial gauge 24 to increase the reading accuracy.
• a drive wheel 28 is rotatably mounted in a projection 26 of the slide. The drive wheel rolls on a tread 30 formed by an edge of the rail 12.
• the drive wheel 28 is provided on its periphery with a toothing or reefing (quasi-toothing) 32, which has a corresponding toothing or quasi-toothing 34 on the barrel surface 30 is engaged.
• the slider 18 comprises a main body 36, the U-shaped manner the rail 12 from one side, and ei ⁇ nen from the opposite side of the rail aufsteck ⁇ cash lid 38.
• the main body 36 and the cover 38 form one half of the Projection 26.
• the drive wheel 28 is manufactured in one piece with an axis made of plastic formed by two bearing pins 40.
• the bearing journals 40 are each movably mounted in an elongated hole 42 of the main body 36 or of the cover 38 designed as a blind hole.
• the elongated holes form an angle of, for example, 45 ° with the longitudinal direction of the rail 12.
• the ratchet mechanism remains ineffective if internal dimensions are measured with the measuring tongues 16 and 22, since in this case the drive wheel 28 is rotated counterclockwise in FIG. 2.
• the obliquely arranged elongated holes 42 can also be replaced by V-shaped or arcuate grooves, so that a ratchet effect is achieved in both directions.
• the action of the ratchet mechanism can be partially canceled out by the drive wheel being pressed firmly against the running surface of the rail.
• Modified ratchet mechanisms are to be described in which the force transmitted from the drive wheel to the slide is independent of the pressure force exerted on the drive wheel.
• the drive wheel 28 is formed in a ring shape and provided with an internal ring gear 44.
• a shaft 46 is rotatably mounted in the internal ring gear 44 of the drive wheel with little play.
• the shaft 46 ' is provided on its outer circumferential surface with a recess 48, from the bottom of which a leaf spring 50 integrally molded onto the shaft "projects radially outwards. The free end of the leaf spring 50 is in engagement with the ring gear 44.
• the shaft 46 is connected in a rotationally fixed manner to two drive wheels 52, 54 arranged at the opposite ends of the shaft.
• the corresponding diameter of the drive wheels 52, 54 is larger than the diameter of the drive wheel 28, and the outer circumferential regions of the drive wheels run past the side surfaces of the rail 12 at a short distance.
• the lateral end faces of the drive wheel 28 are received by flat recesses 56 on the mutually facing inner surfaces of the drive wheels.
• the drive wheel 52 is detachably attached to the end of the shaft 46, while the drive wheel 54 is integrally connected to the shaft.
• the drive wheel 28 has a circumferential groove 58 on its outer circumference.
• a bracket 60 fastened to the slide 18 and opened in a U-shape relative to the rail 12 runs through the groove 58, so that the arrangement of drive wheel, shaft and drive wheels is rotatably held on the edge of the rail 12.
• the groove 58 has a trapezoidal cross section that widens outwards.
• the edge of the rail 12 extends tangentially through the groove 58 and is at an incline Flanks in frictional engagement. This ensures reliable power transmission from the drive wheel to the rail even when the rail 12 is made of metal and is not provided with teeth. If the rail has teeth, the drive wheel 28 can be replaced by a corresponding drive wheel provided with an external ring gear.
• the drive wheels 52, 54 which are corrugated on the outside, are rotated with the thumb.
• the torque is transmitted through the leaf spring 50 of the shaft 46 to the drive wheel 28, which rolls on the rail 12.
• the leaf spring 50 and the inner ring gear 44 of the drive wheel form a ratchet mechanism which limits the driving force to a predetermined value. This limit is, however, not dependent on the strength of de * r leaf spring and the shape of the teeth of the internal gear 44 by the force applied to the drive wheels and the drive wheel in the direction of the rail 12 contact force. With a symmetrical shape of the teeth of the internal ring gear, the limit value at which the ratchet mechanism is effective is the same for both directions of rotation.
• FIGS. 6 and 7 show a modified ratchet mechanism which, similar to the ratchet mechanism shown in FIGS. 1 to 3, is mounted in a projection 26 of the slide 18.
• the shaft 46 can be rotated on an axle pin 62 and is only provided at one end with a drive wheel 64, the corrugated peripheral edge of which projects through a gap 66 between the main body 36 and the cover 38 of the slide 18.
• the axle pin 62 is connected in one piece to the main body 36 and engages in a recess 68 in the cover 38.
• the drive wheel 28 is optionally provided with an external ring gear 34, as shown in the drawing, or with a friction surface encompassing the edge of the rail 12.
• the circumference of the drive wheel is covered by a flange 70 formed on the main body 36 'of the slide, so that the drive wheel can only be actuated via the drive wheel.

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Length-Measuring Instruments Using Mechanical Means (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=6242353

Family Applications (1)

Country Status (3)

Cited By (3)

Families Citing this family (1)

Citations (7)

• 1985
  • 1985-08-01 JP JP60503710A patent/JPS62500047A/ja active Pending
  • 1985-08-01 WO PCT/EP1985/000395 patent/WO1986001285A1/de not_active Ceased
• 1986
  • 1986-08-01 CH CH134486A patent/CH669661A5/de not_active IP Right Cessation

Patent Citations (7)

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