Abstract: In a method for checking and monitoring the friction between the traction sheave and the suspension ropes of an elevator, the slippage between the traction sheave and the suspension ropes of the elevator is measured, the elevator comprising an elevator machine, a hoistway and an elevator car and a counterweight moving in the hoistway. The rope slippage is measured either periodically by performing test drives or continuously by means of an impulse device placed in the elevator machine and measuring the motion of the tractin sheave, an impulse device monitoring the movement of the elevator car and an impulse device monitoring the load in the car. The data provided by these impulse devices is transmitted to a computer which calculates and monitors the relative slippage between the traction sheave and the suspension ropes of the elevator.

Abstract: According to the present invention, an apparatus for measuring a resistance against slippage on the road surface is so constructed that two measuring wheels adapted to be rotated by imparting a tractive force to the apparatus are connected to one another via a torsion bar extending therebetween, a difference in rotation is forcibly produced by changing a rotational speed of one of the measuring wheels and a slippage resistance on the road surface is measured by detecting a torque generated on the torsion bar due to the slippage resistance on the road surface.

Abstract: An improvement in a Horizontal Pull Slipmeter (HPS) enables more accurate and more rapid coefficient of friction measurements to be made upon walking surfaces. The improvement involves a specialized interaction between a drag sled and a stationary pulling mechanism which in conventional HPS devices, are seperate entities. The specialized interaction utilizes paired tracks which extend from the pulling mechanism and serve to guide the drag sled. The pulling mechanism utilizes a motor which is automatically activated when the HPS is placed on the walking surface and pulls the drag sled at a constant speed.

Abstract: A device for testing a ski sliding surface comprising a case (1) housing a spiral spring (3) having one end thereof attached to case (1) and the other end to an axle (4) rotatably disposed with respect to case (1), and a support bushing (7) attached to one end of axle (4). The end of the support bushing (7), which is exterior to case (1), holds a disk (8) whose end face (9) intended for interaction with snow or snow imitation surface is made of a material forming the test ski sliding surface. A measuring mechanism for measuring relative rotation of the disk (8) and the case (1) is designed as a ratchet-and-pawl mechanism (10) which has a gear (12) secured on the axle (4) and is provided with a switch (11) for step-by-step engagement of spring-loaded pawls (13, 14) with the gear (12), a scale (18) for sliding capacity measurement disposed on case (1), and a pointer (19) fixed on the other end of axle (4).

Abstract: There is disclosed a thread friction measuring arrangement comprising first and second strain gauges arranged in a thread path either side of a cylindrical surface against which friction is to be measured so that the first and second strain gauges give electrical outputs respectively corresponding to the tension in the thread before and after turning around the surface, and further comprising electronic components for computing the frictional coefficient of the thread in the surface from the electrical outputs.

Abstract: A system for determinng the road adhesion of a tire installed on a road wheel of an automotive vehicle operating on a roadway includes a road wheel turn angle measuring device, a vehicle speed measuring mechanism and a steering force measuring mechanism. Information regarding turn angle, vehicle speed and steering force are fed into a processor which determines the road adhesion of the tire.

Abstract: An apparatus and method for monitoring the relationship between the sidewalls of a carrier for a seal. A probe engages the sidewalls and responds to the frictional resistance to movement of the carrier with respect to the probe. If the frictional resistance is outside a preselected resistance, an indicator informs an operator of an out of tolerance condition needs to be corrected in order to manufacture a carrier with insertion and removal characteristics required to retain the seal on a projection surrounding a opening.

Abstract: A microprocessor-based interactive apparatus to compute coefficients of static and dynamic friction for a test surface using deceleration data of a weighted block sliding to a rest on the test surface. The apparatus provides an accessible graphical display of the recorded deceleration data which comprises a series of relative time values and associated block acceleration values. A movable cursor permits the user to interactively select the point on the surface for which the coefficient of friction is to be computed. The computed coefficient is then displayed on the graphics display device with the deceleration plot. The cursor may then be redisplayed and moved horizontally with respect to the graphical plot of the deceleration data so that another coefficient of friction may be computed and displayed for a different selected point.

Abstract: The invention pertains to a device for checking the surface condition of materials. The disclosed device is essentially comprised of an adherence measuring sensor whose sensitive element is set in contact with the surface of the material, in relative motion with respect with said surface, and an associated computer which provides for the comparative measurement, the display and the possible piloting of the surface treatment or production apparatus. The sensor comprises two wheels (1 and 2) mounted on fluid bearings (3) and rolling on the material (4) of which the surface condition is to be controlled and devices (5 and 6) for measuring the speed differential, of the wheels (1 and 2) and providing for the progressive braking of one of the wheels (2).

Abstract: A portable apparatus for testing the slip resistance of surfaces such as floors and bathtub surfaces operates by applying a load instantaneously to a pad of friction material resting on the surface at a selected angle of attack. An articulated linkage carrying the pad is set at a predetermined angle and the load is substantially instantaneously applied to determine whether the pad slips at the preset angle. Tests may be successively conducted at different angles of the linkage or a single go, on-go test may be conducted at a datum angle. The articulated linkage is carried on a pivoted frame which moves across a segment plate to establish the predetermined angle. A pawl and tooth type latching system holds the frame relative to the plate at the preset angle.

Abstract: In a method for determining the coefficient of friction between a vehicle tire and a roadway one of the vehicle wheel is pressurized during normal brake operation at a higher pressure than another wheel. The rotational speed of the braked wheel is compared with the rotational speed of another non-braked wheel for determining the wheel slip. Furthermore, the axle load of the braked wheel is measured. On the basis of wheel slip, brake torque and axle load, the coefficient of friction is determined.

Abstract: In a method for determining the friction torque of a test bearing, wherein one race member of the test bearing is rotated at a constant rotational speed, while the other race member is connected via a measuring head to a spring acting as force pickup which generates a signal for a measurement of the friction torque of the test bearing, in order to simultaneously enable in a simple manner a high time resolution and calibratability of the friction torque, it is proposed that the motion of the system comprising measuring head and force pickup be damped as little as possible, that in order to calibrate the entire test device, the test bearing be replaced by an air bearing, that with this air bearing arrangement a signal proportional to the spring deformation and a signal proportional to the measuring head acceleration be generated, that a composite signal be formed from the two signals and the relationship of these two signals be set so that they cancel each other out, and that in the measurement of the friction

Abstract: A machine is presented for measuring normal and tangential belt forces as well as the grinding friction force all versus the angular position for abrasive belt grinding. Normal and tangential force transducers, having the same surface shape and surface finish as the contact pulley, are assembled in the contact pulley. The instrumented contact pulley is used as a driving or driven pulley. A variable speed D.C. motor rotates the driving pulley. A cylindrical workpiece is driven by a variable speed A.C. motor through a torque sensor. The torque sensor determines the grinding friction force between the workpiece and the belt. The A.C. motor-torque sensor assembly is mounted on a carriage plate which slides on two rails with linear bearings. Means are provided for applying a predetermined belt tension and means are also provided for applying a workpiece grinding normal force.

Abstract: A portable apparatus for testing the slip resistance of surfaces such as floors and bathtub surfaces operates by applying a load instantaneously to a pad of friction material resting on the surface at a selected angle of attack. An articulated linkage carrying the pad is set at a predetermined angle and the load is substantially instantaneously applied to determine whether the pad slips at the preset angle. Tests may be successivley conducted at different angles of the linkage or a single go, no-go test may be conducted at a datum angle. The articulated linkage is carried on a pivoted frame which moves across a segment plate to establish the predetermined angle. A pawl and tooth type latching system holds the frame relative to the plate at the preset angle.

Abstract: There is disclosed a portable apparatus (10) for measuring relative coefficients of friction of a cnoveyor belt (12) or other work surface. A rounded contact shoe (38) contacts the surface while suspended between two flanking wheels (18,20). The shoe (38) forms one end of a lever arm (68) which is variably spring loaded at the opposite end to constantly urge the shoe (38) into contact with the moving test surface (42). The relative resistance is measured by a detector means, such as a load cell or strain gage (44) mounted in connection with the lever arm (68).

Abstract: Apparatus for the measurement of surface friction of surfaces, in particular of surfaces designed for traffic, such as road surfaces, floor coverings, and similar surfaces. The apparatus includes a supporting assembly that can be positioned on the surface to be measured, and the supporting assembly supports a shaft of a rotor that is rotatable about an axis perpendicular to the surface and carries at least one contact member. A measuring device is provided for the measurement of the torsional resistance to rotation of the rotor as a result of contact between the contact member and the surface.

Abstract: A fluid cylinder control method for monitoring the position or controlling the movements of a piston which is slidably guided in a cylinder tube and is acted upon on at least one side by a pressure medium, in particular, maintaining the piston in a predetermined position against the action of eventual disturbance forces. This is attained in that the force which is transmitted between the piston and the cylinder by way of the parts which are slidingly guided on each other, and in particular the friction force acting by way of the seal gaskets of the piston and/or of the rod, is measured and the loading of the piston by a pressure medium is varied in the sense of reducing the measured force.

Abstract: A bearing friction testing apparatus includes a bearing support structure having a support arm with a bearing mount for mounting a test bearing with a bi-directional load support ring for attachment to the bearing race with a pendulum attachable to the support ring for adding one direction of force and a tension line attached to the ring for applying a second direction of force transverse to the first direction of force with a pendulum latching device for latching the pendulum in a loaded position and releasing the pendulum with a measuring instrument for measuring the rate of decay in the amplitude of oscillation of the pendulum.

Abstract: Apparatus for measuring friction characteristics of a vehicle-travelled surface comprising a wheeled vehicle having a test wheel assembly pivotally suspended therefrom by a parallelogram suspension arrangement. The test wheel assembly includes a test wheel carried by a drive shaft which is driven at predetermined slip by a differential coupled to the vehicle wheels. A gear chain extends from the differential to the drive shaft through a housing which forms one arm of the suspension. The second arm is formed by a rod which extends from the differential to one section of a two-axis strain gage wheel force transducer at the test wheel assembly. The differential is suspended by parallel struts from the vehicle frame. A positive displacement pump is coupled to the differential for placing a film of water beneath the test wheel having a thickness which is independent of vehicle speed. The pump and test wheel are clutch driven.

Abstract: The coefficient of the dynamic friction of the surface of a memory disk or disks may be measured by tilting the entire memory unit, with the magnetic head being mounted for limited movement in the direction of relative movement of the head and the surface. The movement of the memory disk initially carries the head to its extreme position in the direction of movement of the disk. At a certain angle, as the memory unit is tilted from the horizontal toward the vertical, the weight of the head will overcome the dynamic force of the disk-head drag and the head movement to its lower position will be sensed; and the operative component of the weight of the head and its mount at the critical angle will be substantially equal to the dynamic drag or frictional force between the head and the associated disk or disks.

Abstract: Measurement of the skin friction of piles, according to which a skin-friction measuring device having a cylindrical testing part which is rotatable relative to a main body of the device is introduced into a bored hole in a ground and is rotated by a boring rod, and by rotating the boring rod, the friction force then generated between the cylindrical testing part and the wall of the bored hole is determined in terms of the torque required for rotating the cylindrical testing part.

Abstract: An apparatus for measuring torque characteristics of devices (20, 73) includes a first shaft (19) having torque applied thereto by a first device (20) and a second shaft (41) having torque applied thereto by a second device (73). Sensing elements (31) are provided which detect the forces generated by the torque of the first and second shafts (19, 41) and produce electrical signals proportional to the forces detected. A first coupling device (25) transfers the forces generated by the torque from the first and second shafts (19, 41) to the sensing elements (31). A suspension mechanism (57) permits the second device (73) to move laterally independent in two spatial dimensions with respect to the first device (20) so as to minimize any effects from mechanical misalignment and the structural support frame (10). The apparatus can be adapted to measure frictional characteristics of devices (20, 73) by providing an actuator (93) for applying a torque to a third shaft (92).

Abstract: A dynamic friction coefficient measuring apparatus includes a friction measuring portion having a disc with a friction measuring rubber member attached thereto, a driving disc adapted to rotate coaxially with the disc and a dynamometer which interconnects the disc and the driving disc. A tachometer measures the speed of the rubber member during rotation of the friction measuring portion. An X-Y recorder records two electric outputs of the friction measuring portion and the tachometer onto rectangular coordinates.

Abstract: A slip sensing mechanism for a multilink or articulated belt drive includes a flexible arm on which is disposed a roller maintained in abutment with the belt. The flexible arm has formed integrally therewith or otherwise secured thereto a strain gauge which will provide a measurement proportional to the deflection of the arm. This deflection is indicative of the radius at which the belt is operating relative to a pulley. The roller in abutting the individual link members of the belt causes an oscillating or AC component which is measured by the strain gauge. This AC component is proportional to the speed at which the belt passes thereunder. It is possible by knowing the rotary speed of the pulley and the radius by which the belt is operating to calculate the slip speed, if any, of the belt relative to the pulley by obtaining the difference between the product of pulley speed and belt radius and the product of link width and frequency.

Abstract: An apparatus for testing the friction and susceptibility to damage by casters of various floor materials. A sample of floor material is moved under a caster wheel by a moving table. The caster orientation, pressure and size are variable. Forces on the caster are monitored by instruments which also read the reaction of the floor sample to the test. Records are produced both in tabular and in graphic form.

Abstract: Method and a device for inspecting the operation of a valve. The valve (1, 11) is placed on a test bench (2, 3) capable of applying an opening and closing force to the valve, a representative graph of the movement of the valve as a function of the force applied is plotted, the coordinates of which are measured continuously, and the graph of the test is compared with a reference graph (C.sub.1) in order to detect operating defects according to the positions of the valve. The invention is applicable to the inspection of valves for passing fluids, more specifically in the nuclear industry.

Abstract: The invention disclosed includes a method of and apparatus for measuring the subsurface bearing strength of soil and the frictional resistance of the soil to movement of a pile through the soil. A probe is used for this purpose that includes two relatively movable members, an inner plunger with a flat face, and an outer tubular member. By measuring the forces imposed by the soil at different locations on the probe as the relatively movable members of the probe are moved through the soil the bearing capacity and the skin friction of the soil can be calculated.

Abstract: The tension of filamentary material under tension in a process can be measured with improved accuracy. The measurement is effected by the tension measuring device having an elongated, externally insulated housing which substantially surrounds and encompasses a solid, continuous beam cantilever-mounted coaxially with the housing. The beam extends beyond the housing through an opening at the other end of the housing from its mounting to an engagement means for the filamentary material. The beam has at its distal end within the housing two or more target means located in a relationship to each other along different axes in the same plane where the target means are in sensing engagement with a sensing means which extend into the housing from a point of attachment on the housing. The opening of the housing is substantially covered by a shield through which the beam passes and to which there is mounted a strand contacting means.

Abstract: To determine aquaplaning or, in general, the adhesion factor of tires of a vehicle on a road surface, test braking pressure (p.sub.1, p.sub.2, p.sub.3, p.sub.4) is applied to a wheel or wheels, preferably the rolling wheels, of a vehicle. Wheel slip, that is, difference between deceleration of a wheel and deceleration of the vehicle is determined upon application of the test pressure, and an output signal is generated, indicated of wheel slippage, if a given wheel slip occurs at a test pressure below that which would be expected on a gripping or rough surface, so that wheel slippage with respect to the road surface is determined early. The test braking cycle can be initiated manually (switch 12) by an operator, from time to time, and, preferably, can be commanded automatically by an antibrake lock system (ABS, 10) by applying a braking pressure well below that required, for example, for vehicle operation under traffic conditions, and merely to determine wheel slippage.

Abstract: An accident reconstruction device is provided which allows for simple and accurate measurement of the coefficient of friction for a given surface. The device comprises a metal H-beam, I-shaped in vertical section, having a rubber tire tread affixed to its lower flange and a hole at one end positioned at the vertical center of mass of the device. The device is pulled along the surface to be tested by a scale which indicates the force required to move the device, thus allowing calculation of coefficient of friction for the surface. By turning the device over, the coefficient of friction between metal and the surface can also be determined by the same device, thus rendering the device particularly useful in determining a composite coefficient of friction for automobile accidents where an automobile has skidded over different surfaces, both on its tires and on metal portions of the automobile body.

Abstract: A diagnostic apparatus for diagnosising of a valve device in a turbine system comprises at least one of a pressure sensor for sensing hydraulic pressure in a hydraulic cylinder for driving a valve body of the valve device and a position sensor for sensing the displacement of the valve body, and a processing device for processing the output signal from the above-mentioned at least one sensor. The processing device has an offset computing device which receives a signal representing the actual operating state of the valve device obtained on the basis of the output signal from the at least one sensor and a signal corresponding to a reference value obtained under the normal operating state of the valve device. The offset computing device is operable to compute the offset between the signals received thereto. A judging device is provided for judging as to whether or not there is a symptom of a sticking in the valve device, in accordance with the output signal from the offset computing device.

Abstract: A sphere with a hole through one diameter is held in a spherical chamber hin a tube. The axis of the tube and the hole through the sphere are out of alignment by some predetermined angle, .theta.. The sphere is held within the chamber and the entire unit is caused to spin. The sphere is released while the unit is still spinning. The gyroscopic nutation of the sphere causes the spherical bore to traverse the angle .theta. and align with the tubular bore in a time dependent upon the sliding friction between the material of the sphere and the material of the spherical chamber.

Abstract: The takeoff weight of an aircraft is computed from measures of the thrust of the engines and the forward acceleration of the aircraft detected over a time period when such acceleration is at a maximum following brake release on the runway. A major variable that must be considered is the coefficient of rolling friction of the landing gear of the particular aircraft involved and other factors inducing ground roll drag. The present invention calculated this variable as a function of engine thrust and manifest weight for each takeoff of the aircraft and updates weighted filter values thereof for use during subsequent takeoffs. For each takeoff, therefore, and average value of rolling friction is used to calculate takeoff weight, which average value becomes more nearly the actual value for the existing condition of the landing gear.

Abstract: An apparatus adapted to be mounted on a surface grinding machine is provided for testing abrasive grains in single-grit scratch tests. To permit specimen preparation and scratching to be carried out on a single machine without changeover and without reclamping the specimen, and to maintain the infeed in the scratching operation constant by giving the specimen a contour corresponding to the cross-feed error, a belt grinder and a scratching device comprising a support disk, mounted by means of a main flange and a counterflange, and a scratching disk mounted on the main flange and carrying a single grain secured to its periphery along with a force-measuring system disposed thereunder, are designed as a structural unit adapted to be mounted on the spindle of the surface grinding machine, with a belt tensioning arm mounted to the headstock.

Abstract: Apparatus for measuring the rolling resistance of tires. An endless belt is supported on rotating drums. The upper run of the belt passes over a hydrostatic bearing which supports the belt against the force of the tire pressing against it. The hydrostatic bearing is formed by a plurality of nozzles directing water at high pressure against the underside of the belt. A pressure differential is created between the upper and lower surfaces of the belt to press the belt closely adjacent the nozzles so that when a tire is pressed against the belt, it does not create a depression in the belt.

Abstract: Apparatus for simulating varying levels of friction in the bearings 13 of a free rolling tail afterbody 11 on a canard-controlled missile 12 to determine friction effects on aerodynamic control characteristics. A ring 16 located between the missile body and the afterbody is utilized in a servo system to create varying levels of friction between the missile body and the afterbody to simulate bearing friction.

Abstract: A method is disclosed for using a tension gauge for comparing the tension required to move a frictional element relative to the nose of a wearer of a pair of eyeglasses when the frictional element is first disposed between and in frictional contact with a first nose pad of the eyeglasses and a first side of the wearer's nose to the tension required to subsequently move the frictional element relative the wearer's nose when the frictional element is disposed between and in frictional contact with a second nose pad of the eyeglasses and a second side of the wearer's nose. The gauge includes an elongated housing which defines a bore extending along the longitudinal length of the housing, a rod slidably cooperating with the bore and a first end of the rod disposed within the housing. A spring is disposed between the first end of the rod and the housing to bias the rod to a retractable position within the housing.

Abstract: The invention disclosed includes a method of and apparatus for measuring the sub-surface bearing strength of soil and the frictional resistance of the soil to movement of a pile through the soil. A probe is used for this purpose that includes three relatively movable members, an inner plunger with a flat face, an inner tubular member, and an outer tubular member. By measuring the force required to move the members through the soil together and separately the bearing capacity and the skin friction of the soil can be calculated.

Abstract: A quasi-static electrical friction sleeve cone penetrometer probe which includes a main body, portion of the body being a cone load cell connectible to a cone for measurement of cone resistance. A friction sleeve load cell is connectible to the main body, and a friction sleeve is connectible to the friction sleeve load cell for separate measurement of side friction. Each load cell has strain gauges attached around an outer surface, and balancing circuitry located within the cell. The friction sleeve is supported against lateral forces by three annular sleeves located on the main body, friction sleeve load cell and the cone.

Abstract: A method of, and apparatus, for determining the direction of force in a moving escalator having a plurality of drive units coupled to an endless, articulated belt. The direction of force, and the duration of such force in a direction which indicates compression of the belt at each drive unit, is used to align and properly space the drive units for optimal load sharing.

Abstract: The decelerating movement of a vehicle during a skid test is sensed by an accelerometer which provides an analog signal representative of the deceleration to a computer where the analog signal is periodically sampled and converted into a digital deceleration signal for storing in a computer memory. Alternatively, the decelerating movement of the vehicle may be sensed by a radar speed detector providing digital signals representative of the initial speed and final speed of a time increment to a computer processor which records and stores the digital speed signals in computer memory to be later recalled to produce a digital deceleration signal. The computer processor effects storing of the digital deceleration signals in the computer memory at the beginning of a skid test when the magnitude of the signals exceeds a predetermined threshold level as sensed by a threshold level detector or, alternatively, when a mercury position switch is operated by the deceleration force.

Abstract: Apparatus and methods are disclosed for detecting slippery road conditions directly from a moving vehicle. A special probe is momentarily lowered to the road surface from the moving vehicle. A coefficient of friction is determined by ratio of the verticle and friction forces. A display provides the operator with a proper indication of roadway conditions.

Abstract: A fixture for measuring the drive forces of a friction drive apparatus. The fixture comprises a first member having a first surface adapted to be located in juxtaposition with the friction drive apparatus. A reaction member is movably supported on the first member such that when the first member is in juxtaposition with the friction drive apparatus the reaction member is in engagement with the friction drive apparatus. The reaction member is movable relative to the first surface in response to the driving force of the friction drive apparatus. The reaction member includes reference means for indicating the relative position of the reaction member and the first surface. The reaction member is urged toward a rest position on the first surface. The magnitude of the urging force is proportional to the displacement of the reaction member from the rest position by the driving force.

Abstract: A method for testing steam turbine admission valve assemblies for determining the operational force margins present therein which are used to diagnose the likelihood of valve inoperativeness due to the build-up of frictional forces in the valve assembly is disclosed.

Abstract: A method and apparatus for testing the setting of a valve (particularly a safety valve mounted on a vessel) comprising a valve member biassed towards a valve seat, employs a pulling device which is engaged with the valve member and operated to apply a tractive force opposed to the bias which is just sufficient to separate the valve member from the valve seat. The pulling device is preferably operated by a hydraulic or pneumatic pump. The hydraulic or pneumatic pressure which is just sufficient to separate the valve member from the valve seat is indicated by a suitable gauge and is proportional to the tractive force. The sum of the tractive force and the force acting on the valve from inside the vessel and which can be calculated from the internal pressure indicated on a pressure gauge communicating with the interior of the vessel is indicative of the setting of the valve.

Abstract: A low friction bearing starting torque apparatus applies a known acceleration to a stationary bearing having a known radial load, to measure the starting torque of the bearing.

Abstract: An apparatus provides a measurement of the running torque of a bearing under a radial load, by utilizing a balanced radial load on the bearing and a pendulum weight. The steady state running torque of the bearing is proportional to the sine of the deflection angle of the pendulum weight.

Abstract: Strain gauge devices are mounted on the brake shoe carrying levers of an underground mine winding engine to sense induced strain and effective braking force when the brake is applied. A summation unit adds outputs from strain gauges. Indicators are operated by the result to indicate the effective braking force. A comparator compares the result with predetermined desired braking levels. Controls prevent release of other brake devices until the effective braking force exceeds a preselected magnitude.

Abstract: An apparatus for measuring the action of forces between a wheeled vehicle and a substructure wherein the invention relates to the improvement of a measuring apparatus having a plurality of controls for selecting measuring distances of varying lengths, with each control programmed to trigger, when actuated, a memory in an electronic unit arranged to compare a signal value preselected to represent the measuring distance with a signal value generated by summing up output signals from a vehicle speed transducer and wherein the electronic unit is programmed to trigger discontinuation of the measuring sequence when the two signal values are equal which will be obtained at the end of the measuring distance.

Abstract: A testing apparatus for testing the sliding characteristics of the soles of ski boots. The testing apparatus includes a lever arm for applying a downwardly directed force onto an upwardly facing boot sole adjacent structure engaging either the toe or heel of the ski boot. A drive mechanism is utilized to draw the member which is applying the downwardly directed force laterally of the ski boot. A measuring device is provided for detecting the sliding characteristic of the member which applies the downwardly directed force onto the upwardly facing boot sole.