Abstract: A method for characterising instrument error in a surface measurement instrument, comprising obtaining first calibration measurement data representing a known surface form of a first reference object and obtaining second calibration measurement data representing a known surface form of a second reference object. At least a portion of the second calibration measurement data represents a measurement range that overlaps with at least a portion of a measurement range of the first calibration measurement data. A common error function is obtained that characterises the instrument error.

Abstract: A measuring wheel includes a handle that can be folded into a non-use position. The wheel lies in a plane, and the handle moves in a plane coincident with the plane of the wheel between a collapsed position and an extended use position. The handle has a proximal section and a distal section that connect about a pivot point for movement between a collapsed position and the extended use position. The measuring wheel has a releasable engagement member associated with one of the handle sections that releasably holds the handle in the extended position. The releasable engagement member can be disengaged to allow the handle to be collapsed.

Abstract: A measuring wheel includes a handle set, a first rod, a second rod, a wheel seat and a wheel. The first rod is mounted on the handle set and has a first seat mounted on the first rod. The first seat includes a first body, a first pivotal portion and a buckling unit. The first body has an assembling groove and a supporting recess. The second rod is pivotally connected with the first rod and has a second seat assembled with the first seat. The second seat includes a second body and a second pivotal portion. The second body has a supporting block and a buckling groove defined in the supporting block. The buckling unit has an end aligning with an outer periphery of the supporting recess in the bottom surface of the first body to prevent from hitting.

Abstract: A distance measuring device having a frame defining an operating handle. At least one wheel is mounted to the frame. A counter mechanism on the frame has a display and a reset mechanism. An actuating mechanism has components cooperating between the at least one wheel and counter mechanism for causing cumulative distance measurements to be identified on the display as the at least one wheel is rolled against an underlying surface. The counter mechanism has a reset actuator that is moved from a retracted position into an actuated position. The reset actuator has a surface with an engaging area. The distance measuring device further has at least one stop component that defines a blocking surface to arrest movement of a component, having an area that is greater than the engaging area, that is pressed against the surface of the reset actuator to thereby move the reset actuator from the retracted position into the actuated position.

Abstract: The present invention relates to a system for measuring data in a well extending below surface, said system comprising a body having a longitudinal axis and a front end and a rear end; locomotion means; control means adapted to control direction and/or speed of the locomotion means; said control means being controllable from the surface. Thereby is achieved that a body may be remotely controlled from the surface e.g. the entrance of an oil well.

Abstract: A sheet length measuring device includes a rotating body configured to rotate with a movement of a sheet in a conveying direction; a position detecting unit configured to detect leading and trailing ends of the sheet passing through a position of the rotating body; a measuring unit configured to measure a rotation amount of the rotating body and output an origin signal per one revolution of the rotating body; a storage unit configured to store changes of a sheet conveying amount with respect to respective rotation angles in one revolution of the rotating body; and a calculating unit configured to calculate a corrected length of the sheet from a value obtained from a rotation angle of the rotating body when the leading end of the sheet is detected and a value obtained from a rotation angle of the rotating body when the trailing end of the sheet is detected.

Abstract: A method and apparatus for measuring distance on a loose surface is disclosed. The apparatus includes a frame and a wheel operatively coupled to the frame. The wheel rotates relative to the frame. Further, the wheel includes a hub for operatively coupling the wheel with the frame. The hub rotates relative to the frame in response to one of pushing and pulling of the frame. To increase traction between the wheel and the loose surface, a plurality of spikes is provided on a peripheral surface of the wheel, projecting outwardly away from the hub. As the peripheral surface rolls on the surface, the distance traversed by the wheel is measured by calculating the number of rotations made by the wheel. A counter is operatively coupled to the wheel for tracking the number of rotations made by the wheel as the peripheral surface of the wheel rolls on the loose surface.

Abstract: A tape checking apparatus has a driving roller (42) interposed in a running path (L) of an endless tape (T) and a thickness-measuring device (44) disposed near the driving roller (42). The thickness-measuring device (44) measures the thickness of the endless tape (T) that is pinched between the driving roller (42) and a pinch roller (45).

Abstract: A method and system for monitoring a fleet-angle of a cable. An embodiment may monitor the fleet-angle of a cable being spooled or unspooled in multiple radial directions and without use of a mechanical monitoring apparatus. The method and system may employ a fleet angle sensor device having a bell-shaped aperture across which propagate one or more collimated light beams that may be used to detect excessive fleet-angle of the cable. The light beams may be generated by a fleet-angle sensor disposed in the fleet angle sensor device proximate to the aperture. Various light-beam patterns within the aperture may provide different advantages when determining deviations of the cable from the aperture center axis.

Abstract: A method and apparatus for measuring distance on a loose surface is disclosed. The apparatus includes a frame and a wheel operatively coupled to the frame. The wheel rotates relative to the frame. Further, the wheel includes a hub for operatively coupling the wheel with the frame. The hub rotates relative to the frame in response to one of pushing and pulling of the frame. To increase traction between the wheel and the loose surface, a plurality of spikes is provided on a peripheral surface of the wheel, projecting outwardly away from the hub. As the peripheral surface rolls on the surface, the distance traversed by the wheel is measured by calculating the number of rotations made by the wheel. A counter is operatively coupled to the wheel for tracking the number of rotations made by the wheel as the peripheral surface of the wheel rolls on the loose surface.

Abstract: A brake mechanism for a wheeled distance measuring device includes a first brake rod and a second brake rod, both of which are located in a pole unit of the distance measuring device. The first brake rod is connected with a brake key and the second brake rod is connected with a contact section which has a brake pad connected thereto. The brake key includes first and second protrusions and a control rod is connected with the first brake rod, the control rod includes third and fourth protrusions. A locking recess is defined between the third and fourth protrusions. The first and second brake rods are lowered to brake the wheel by the brake pad when the first protrusion presses the third protrusion. The second protrusion is locked in the locking recess and presses the third protrusion to keep the wheel to be braked.

Abstract: A tape checking apparatus has a driving roller (42) interposed in a running path (L) of an endless tape (T) and a thickness-measuring device (44) disposed near the driving roller (42). The thickness-measuring device (44) measures the thickness of the endless tape (T) that is pinched between the driving roller (42) and a pinch roller (45).

Abstract: A stud marking device for easily and quickly marking locations of studs. The stud marking device includes a handle having a tubular base member having a pair of prong-like members extending outwardly from a bottom thereof, and further having three telescopic members slidably and lockingly extended within one another, and further includes a wheel being of many different sizes and being rotatably mounted to the prong-like members. As a first embodiment, the wheel has a bore radially extended through the circumference with a marker being threaded in the bore and having a marking end which extends outwardly beyond the circumference.

Abstract: A wheeled distance measuring device includes a wheel with a measuring unit connected to a side of the wheel and a pole unit is connected to the wheel, the pole unit includes a first section, a second section and a third section. The first section has two first holes and two second holes defined in two ends thereof. The first section is movably inserted into the second section which has two third holes and movably inserted into the third section which has two fourth holes. Two positioning units are respectively located between the first and second section, and between the second and third sections. The positioning units control the retractable movement of the sections so as to adjust the length of the pole unit. A handle is connected to the pole unit and controls the positioning units by an action rod.

Abstract: A measuring device includes a frame, a rolling wheel carried by the frame, measuring means for determining a distance traveled by the wheel, and signal means responsive to the measuring means for indicating when the wheel has traveled a preselected set distance. The measuring device may also include marking means such as spray paint, a braking mechanism, and a sonar position indicator.

Abstract: A wheeled distance measuring device includes a housing attached to a pole, a counter attached to the housing and having a spindle extended out of the housing, and two gear members of different diameters selectively attached to the spindle, a wheel including a wheel axle attached to the housing, a carrier adjustably attached to the housing, a gear element rotatably attached to the carrier for selectively engaging with either of the gear members, and a gear coupling mechanism coupled between the wheel axle and the gear element for allowing the gear element to be rotated by the wheel axle to rotate either of the gear members and for forming either a metric or a British scale or unit or system.

Abstract: A wheeled distance measuring device includes a longitudinal pole having two segments, a housing and a casing attached to the segments and pivotally coupled together, a latch device pivotally attached to the housing and having a latch, and a lock device pivotally attached to the casing and having a catch for engaging with the latch of the latch device and for detachably securing the segments together. The casing includes a chamber formed by a wall for receiving the lock device, and a channel formed in the wall for pivotally engaging with a water-drop-shaped pivot member of the lock device and for pivotally attaching and coupling the lock device to the casing.

Abstract: A wheeled distance measuring device includes a wheel unit having a wheel and a front fork with which the wheel is rotatably connected. A pole unit is connected to the front fork and a handle is connected to a top of the pole unit. A measuring unit is connected to a side of the front fork and a brake unit and an initialization unit are connected to the measuring unit. The brake unit and the initialization unit have a brake key and an initialization key received in the handle. Two respective rods are connected to the brake and initialization keys respectively and extend through the pole unit and connected to the measuring unit. By operating the brake key and the initialization key, the wheel can be braked and the measuring unit can be initialized respectively.

Abstract: A method of calibrating once-around and harmonic errors of encoded nips is provided. An encoder with an index pulse is used to measure the velocity and rotation of the driven wheel or idler. The geometry of the drive train and wheel and idler is chosen so that their once around and harmonic frequencies are unique such that no other drive errors will generate these frequencies. The method includes running the idler or wheel at substantially constant velocity for N revolutions. Each index triggers the collection of velocity data, which is averaged for N revolutions. This process detects drive train motion errors that are periodic with respect to the timing of the index pulse (i.e., once per revolution of the wheel or idler). Once the velocity errors have been measured, corrections are made. This method may be incorporated in xerographic machines as part of a setup or calibration procedure.

Abstract: An apparatus that accurately measures rope, wire, tubing and other materials is herein disclosed. A variety of different-sized models would possess different sized openings. One model with a one-inch opening would be used to measure small wire and cable. Another model with approximately a 3-inch opening would be used for larger electrical cables, rope, tubing and the like. An even large model would be available for measuring ductwork, hoses, and other large diameter material. As the material is pulled through the opening, an optical sensor, similar to that used on an optical computer mouse, accurately measures the material to the fraction of an inch. A mechanical sensor, utilizing a guide wheel is also envisioned. The length is displayed on a digital readout on the perimeter of the invention that is provided with a power button, reset button and the like.

Abstract: A measuring wheel includes a hollow handle respectively having a grip handle and a fork pivoted with a wheel at an upper and a lower end thereof. A counter is mounted on the grip handle or the handle, and inside of the handle has a link rod having a shock absorber. Both ends of the link rod are connected with the wheel and the counter respectively, whereby the rolling distance of the wheel is shown on the counter.

Abstract: An electronic measuring tape (11) that comprises a roller (8) onto which the measuring tape (12) is arranged to be wound up onto and wound out from through the roller (8) being rotated, a first end (3) of the measuring tape (12) is attached in the roller (8), and where the roller (8) is located inside a housing (9a, 9b). The invention is characterised in that a rolled up measuring tape (12) is arranged in loops on the roller (8), of which all loops are in direct contact with the surface (1) of the roller (8), in that an angle sensor (6) is arranged at the roller (8) arranged to record an angle of rotation during the rotation of the roller (8), and in that an electronic circuit (15) is arranged to convert the said angle of rotation into a length that corresponds to the length by which the measuring tape (12) has been withdrawn from the said housing (9a, 9b), and in that the measuring tape (12) records absolute values.

Abstract: A tubing counter for counting coiled tubing inserted into a well includes an outer housing having a through passage for receiving the coiled tubing therethrough. In some embodiments, pressure rated connectors at both of the ends of the outer housing sealably connect the outer housing in series between the coiled tubing injector head and the outer casing of the well. A plurality of counting wheels are rotatably supported within the outer housing for rolling engagement along coiled tubing inserted through the outer housing while a counting mechanism records a number of rotations of each counting wheel independently of the other wheels to minimize counting errors. Locating the counter below the injector head and below the tubing stripper ensures that the tubing is cleaner and less likely to slip in contact with the counting wheels while also accounting for stretching of the tubing for more accurate measurement.

Abstract: The present disclosure relates to a sensor unit for the position determination of a powered door having a position sensor and a transmission stage for the connection of the position sensor to the drive shaft of the door, with the sensor unit having its own housing so that it can be installed independently of the drive unit of the door.

Abstract: An electronic measuring device is disclosed which includes a pair of wheels connected to an axle that passes through a drive gear. The drive gear is enmeshed to a second gear which, in turn, is coaxially connected to an encoder disk. The encoder disk has spaced-apart fins around its outer periphery. As the wheels turn and the encoder disk rotates, the fins and openings between the fins pass between an emitter and a receiver. The emitter and receiver are linked to a controller which calculates the distance traversed by the wheels based upon the number of fins that pass between the emitter and receiver, or with an active counting system (ACS). The controller also includes functions to establish start and stop points for a measurement and an easy means for dividing a measured distance into equal parts or segments and a means for marking the boundary points that define the segments when the measuring device is rolled back across the measured distance. The device can be used on both planar and non-planar surfaces.

Abstract: As a rule, measuring cable position sensors consist of an axial arrangement of flat spiral spring, cable drum, and encoder. By locating the flat spiral spring within the interior of the cable drum, the construction length is reduced on one hand, and it becomes possible on the other hand to locate the cable outlet in one of the outer corners of the housing, which improves the application capabilities of the sensor.

Abstract: An indicating device with large graduations for a plane is installed at a combining section of a main base and a worktable of the plane, including a graduation ruler, a pointer and a rack. The graduation ruler formed as an arc is provided with graduations with number figures for readings. The upper end portion of the pointer faces exactly to the graduation ruler for pointing to one of the graduations. The pointer has gear teeth in its lower round edge for engaging with gear teeth located on one side of the rack. Therefore, a displacement the worktable moves relative to the main base can be clearly and easily read from the graduations of the graduation ruler.

Abstract: An electronic measuring device is disclosed which includes a pair of wheels connected to an axle that passes through a drive gear. The drive gear is enmeshed to a second gear which, in turn, is coaxially connected to an encoder disk. The encoder disk has spaced-apart fins around its outer periphery. As the wheels turn and the encoder disk rotates, the fins and openings between the fins pass between an emitter and a receiver. The emitter and receiver are linked to a controller which calculates the distance traversed by the wheels based upon the number of fins that pass between the emitter and receiver, or with an active counting system (ACS). The controller also includes functions to establish start and stop points for a measurement and an easy means for dividing a measured distance into equal parts or segments and a means for marking the boundary points that define the segments when the measuring device is rolled back across the measured distance. The device can be used on both planar and non-planar surfaces.

Abstract: An apparatus for establishing a golf practice range by at least one of measuring distances for such practice range and gathering golf balls from such practice range. The apparatus comprises a frame, the frame includes a handle member and an axle member that is engageable with a bottom portion of the frame. There is a pair of wheels having a predetermined diameter, each of the pair of wheels is disposed closely adjacent an outer edge of the axle member and a shag bag having a predetermined shape engageable with the frame. The apparatus has a means, disposed on the axle member, for measuring distance.

Abstract: A handheld apparatus for measuring fish, game, and the like is provided and includes a scale, a camera, and a length measuring device. The scale includes a support member that extends outwardly from the apparatus housing, and a display that is visible through the housing. The support member is configured to suspend an object therefrom for weighing via the scale, and the display is configured to display the weight of an object suspended from the support member. The length measurement device is configured to measure the length of an object and the display is configured to display the length of an object measured by the length measurement device. The camera includes a lens, an image sensor configured to capture images obtained via the lens, and a camera display. The camera display displays an image of an object taken by the camera with weight and/or length information for the object.

Abstract: A distance measuring apparatus having a frame and a wheel rotatable relative to the frame around a first axis. The wheel has a peripheral surface that can be rolled against a surface upon which a distance measurement is to be taken. The distance measuring apparatus further has a counter assembly through which advancement of the distance measuring device can be converted to a distance measurement. The scraper assembly has a scraping edge that is one of (a) adjacent to the wheel, and (b) against the wheel. The scraping edge intercepts foreign matter adhered to the wheel as the wheel is rotated around the first axis to avoid buildup of foreign matter upon the wheel as the distance measuring apparatus is operated.

Abstract: Disclosed is a vehicle wheel measuring apparatus, comprising a push rod, a counter, a wheel, and a gear coupled mechanism, wherein the counter is disposed on top of the push rod. Through the gear coupled mechanism, the axle center of said counter and the wheel axle form a joint relationship having the same rotational cycles. A front yoke is attached to the wheel axle in the end of said push rod, and a set of magnetic element is disposed between the wheel axle and the interior side of the front yoke. This prevents the wheel from rotating by itself that affects actual measured distance.

Abstract: An apparatus for measuring linear distances comprising a wheel to be rolled along a surface to be measured, wherein the wheel comprises a plurality of incremental line markers to facilitate measurement of selected intervals, and wherein the wheel is maintained within a housing dimensioned and configured to measure sizes and angles most often encountered during framing.

Abstract: A distance measuring device includes a housing having a distance meter, a measuring wheel having a wheel axle rotatably engaged into the housing and coupled to the distance meter. A brake wheel is disposed on the wheel axle. A brake arm is pivotally secured in the housing and movable to engage with the brake wheel for braking the brake wheel. A pole includes a foldable structure, a handle is disposed on top of the pole, a brake lever and a handgrip are pivotally secured to the handle and extended out of the handle for being actuated by users, and coupled to the brake arm and the distance meter with flexible brake cable and a flexible wire, which allow the segments of the pole to be folded relative to each other.

Abstract: An electronic measuring device is disclosed which includes a pair of wheels connected to an axle that passes through a drive gear. The drive gear is enmeshed to a second gear which, in turn, is coaxially connected to an encoder disk. The encoder disk has spaced-apart fins around its outer periphery. As the wheels turn and the encoder disk rotates, the fins and openings between the fins pass between an emitter and a receiver. The emitter and receiver are linked to a controller which calculates the distance traversed by the wheels based upon the number of fins that pass between the emitter and receiver, or with an active counting system (ACS). The controller also includes functions to establish start and stop points for a measurement and an easy means for dividing a measured distance into equal parts or segments and a means for marking the boundary points that define the segments when the measuring device is rolled back across the measured distance. The device can be used on both planar and non-planar surfaces.

Abstract: A depthometer for measuring a length of an elongate line. A main wheel is mounted upon a main body component and is in communication with a registering mechanism. Line guides are mounted upon a lower body component. An inner handle connected to the main body component is pulled toward an outer handle connected to the lower body component, in opposition to a spring-like force in the opposite direction, to open the depthometer and position a line within the depthometer. The main body component is automatically moved towards the lower body component via a spring-like force when the inner handle is released, thereby engaging the line in the depthometer in the installed position.

Abstract: A system and method for measuring a three-dimensional object uses a number of elongate measuring members that can be displaced with respect to a base in response to a surface of the object. The displaced distances of the elongate measuring members due to the surface of the object are then determined. The displaced distances are measurements of the object surface.

Abstract: An apparatus for measuring linear distances comprising a wheel to be rolled along a surface to be measured, wherein the wheel comprises a plurality of incremental line markers to facilitate measurement of selected intervals, and wherein the wheel is maintained within a housing dimensioned and configured to measure sizes and angles most often encountered during framing.

Abstract: A distance measuring device having a wheel, a frame, and a distance counter on the frame. The wheel has a radius and an exposed surface that can be rolled against a surface on which a distance measurement is to be taken. The wheel is mounted upon the frame for rotation around a first axis. The distance counter is actuated by the wheel. The frame has an elongate operating arm projecting away from the wheel. The frame has a mounting portion to which the wheel is mounted for rotation. The elongate operating arm is pivotable relative to the mounting portion between an operating state and a store state.

Abstract: A device and system that measures the distance over which a cart, buggy or trolley travels, and that can be mounted easily on a wheel of the cart, buggy or trolley, in particular a golf cart, buggy or trolley. The device includes a housing with a counterweight attached to the lower end of the housing and a measuring device inside the housing. The device further includes an attachment mechanism for attaching the housing to the wheel. The attachment mechanism includes a rotary shaft passing through the interior wall of the housing and rotatable in relation to the housing. The counterweight stops the housing of the measuring device from rotating with the wheel, while the rotary shaft of the measuring device rotates with the wheel. The measuring device consists of magnets in the rotary shaft which generate pulses from sensors mounted within the housing when the wheel turns.

Abstract: A flashlight holder for securing a flashlight to an object. The flashlight holder has a clamp assembly for attaching to the object. A cradle is provided for holding the flashlight. The cradle can be attached to the clamp assembly, or preferably, a riser can be disposed between the clamp assembly and the cradle. Retaining straps are provided to secure the flashlight in the cradle. The retaining straps are removably attached to allow the flashlight to be placed in and removed from the flashlight holder.

Abstract: An electronic tape rule comprising a housing, in which reside a steel tape that can be extended from the housing, a reading system that measures the extent of tape extension, and a sound play circuit that gives a read-out of the result of measurement. When the steel tape is extended from the housing, the reading system measures the extent of tape extension and passes this information to the sound play circuit to report the result of measurement for the convenience of users, especially when the measurement is operated in a dark environment.

Abstract: A distance measuring device for measuring distances between two points. The distance measuring device includes a housing having a top and a bottom. A handle is coupled to the housing. A wheel is rotatably mounted to the bottom of the housing. An electronic distance calculating means calculates and displays a distance traveled by the wheel.

Abstract: An electromechanical dimensioning device measures dimensional attributes of an object and transmits the dimensional attributes from the dimensioning device to a remote receiving device. The dimensioning device converts rotational motion of a measuring wheel into a linear distance traveled by the wheel. In one embodiment, the dimensioning device incorporates a rechargeable battery power source and a radio frequency transceiver, allowing fully portable operation. The dimensioning device also optionally includes a bar code scanner for identifying the dimensioned object.

Abstract: Apparatus and method for measuring circumferential surface dimensions of workpieces. A circular table is mounted with its upper surface in a horizontal plane for both rotational and reciprocal vertical movement. A plurality of through slots in the table extend radially with respect to its central axis of rotation. A like plurality of gripper fingers having both vertical and angularly disposed edges are affixed to a common cable for radial movement with respect to the table axis. When the table is in its upper position the fingers are positioned below corresponding ones of the slots, and when in the lower position portions of the fingers extend through the slots. As the fingers are moved toward the workpiece it is engaged by and rides up the angularly disposed edges until it abuts the vertical edges of the fingers. While the workpiece is supported above the table surface, one or more wheels rotatable about vertical axes are moved to engage the surface to be measured.

Abstract: An electronic hand holdable measuring device for measuring dimension of an article by rolling the device across surface of the article includes a housing 10 and a roller sub-assembly 11. When the roller is worn it can be readily replaced together with an associated raster disc 23 forming part of the sub-assembly. An optical reader is permanently mounted inside the housing.

Abstract: A spring force loaded contact wheel mounted in a stationary position relae to a reciprocating shaft is disclosed. The apparatus of the present invention includes a tensioning assembly for maintaining absolute contact between the contact wheel and the reciprocating shaft wherein the tensioning assembly urges the contact wheel against the shaft to maintain contact therebetween so that the wheel turns as the shaft is linearly displaced. A rotary encoding device is coupled to the wheel for translating the angular and rotational movement thereof into an electronic signal for providing linear displacement information and derivative data with respect to displacement of the shaft.

Abstract: A guided working device (1) is driven by an operable traction motor (2) for movement along a travel rail (3). The working device carries a driver (4) provided with articulated heads for a measuring carriage (5), which measuring carriage always travels the same distance as the working device (1). The measuring carriage travels on a control rail (11) and includes a measuring device (6). A plurality of sliding conductors (17) are also receivable by the control rail (11). The measuring carriage carries a preferably toothed measuring wheel about at least a circumferential portion of which a preferably toothed measuring belt is wrapped. The measuring wheel (7) is pressed, by guided wheels (8) in front of and behind the measuring wheel, against a toothed belt supporting surface which is associated with the control rail (11).

Abstract: A means is provided for measuring distance travelled by a vehicle having a wheel coupled to a vehicle axle disposed within a vehicle axle housing, with the wheel haivng at least one nonmagnetized metal region which rotates with the wheel defining an orbit through which the nonmagnetized metal region passes as the wheel rotates to advance the vehicle. The apparatus includes an inductive proximity sensor and a counter means. The inductive proximity sensor is of the type adapted for detecting the presence of nonmagnetized metal within a sensing distance and producing an electrical response thereto; it is coupled to the vehicle axle housing a preselected distance from the orbit of the nonmagnetized metal region, so that the nonmagnetized metal region is within sensing distance as it passes by the inductive proximity sensor. The counter is coupled to the inductive proximity sensor for receiving the electrical response and producing a display corresponding to the distance travelled by the vehicle.

Abstract: A wheel is provided for a measuring device of the type having a frame, a distance counter having an actuating lever thereon and mounted on the frame, and structure for mounting the wheel on the frame for rotation about an axis. The wheel has an annular surface for engaging and rolling against a surface along which a distance is to be measured, first and second annular side walls spaced axially with respect to the wheel axis and connected to the annular rolling surface with each side wall having a thickness in an axial direction, a hit pin, and structure for securing the hit pin to the wheel so that a part of the hit pin projects axially from one of the side walls to engage and operate the actuating lever on the counter as an incident of the wheel rotating relative to the frame.