The subject of the invention is a device for measuring the elasticity of piston rings comprising a supporting structure consisting of a base, a support and a boom, wherein the supporting structure is equipped with a digital display attached to it, and is connected - on one side with a screw mechanism equipped with a knob, an upper pressing element i.e. jaw and a guiding element - and on the other with a lower part of the measuring mechanism, a pressure piston and a piezoelectric transducer connected to the display.

Polish patent description PL210837 discloses a pressure measuring element, in particular of piston rings, used in devices for measuring the profile of a piston ring. The device according to the invention is characterised in that it comprises a shaped mandrel with a coaxially mounted movable sleeve-shaped slide whose bottom cylindrical section has an L-shaped opening which holds a retaining pin mounted in the central part of the mandrel, wherein the shaft includes a coaxially positioned flexible connecting piece located inside the sleeve-shaped slide and supported on one side by the edge of the inner rise of the sleeve- shaped slide and, on the other side, by the tightening nuts releasably connected with the end of the mandrel with a smaller diameter. Simultaneously, the lower part of the sleeve-shaped slide includes a coaxially mounted protective sleeve-shaped slide and an adequately shaped pressing foot fixed with a nut, wherein the upper part of the sleeve-shaped slide is connected with a protective cap.

The description of the Polish utility model PL60391 discloses a device for measuring the elasticity of piston rings equipped with a clamping strip in the shape of a loop whose one end is fixed in a sliding bolt, and whose other end is mounted in a holder connected with a vibration device. The device disclosed in this description is characterised in that it comprises an electronic force gauge slidably mounted on a vertical stand placed on the base of the device, wherein the tip of the measuring mandrel of the force gauge is connected with one end of the clamping strip loop, wherein the other end of the clamping strip loop is fixed in a holder that is a two- armed lever whose other arm is connected to a vibrator.

From the application EP2249121A1 there is known the measuring sensor that has a base body, two spring-loaded spreading arms supported concentric to a rotational axis on the base body and two radially displaceable tracer pins. The measuring sensor has two sensor lever aligned parallel to the rotational axis, whose an end is in contact with an assigned tracer pin and another free end has a tracer head for scanning a radially symmetrical workpiece surface.

From the application WO9501547A1 we know a gauge for checking linear dimensions of mechanical parts comprises a support casing , substantially arranged along a longitudinal direction, and housing a transducer unit. The transducer unit includes an axially movable rod. A ball-shaped element, movable depending on the dimension of the mechanical part, is fixed at an end of an elongate element, having a second end coupled to the movable rod and a flexible cylindrical section. An abutment member defines an inclined surface portion, having a Vee cross-section, for housing and guiding the ball-shaped element.

In the application GB1331931A there is an apparatus for testing the shape of a concave surface comprises a ball ended member, a mounting for holding a test piece, a device sensitive to linear displacement extending within the member so as to be engageable in use with a point on the concave surface, means for rotating the mounting about an axis thereof and means for rotating this axis about an axis of the said ball. As described a piston slipper under test is placed in cup of plunger assembly. Spring urges the piston slipper into making contact with ball and into contact with the end of plunger of a probe sensitive to axial displacement of the plunger. The output of probe is displayed on a recorder. Switch is closed, then switch is pressed to operate the motor to rotate shaft and thus via gear train to rotate the slipper to a desired position, when switch is released. Plunger is pushed in against spring and turned so that peg engages a step in recess to retain the plunger. This action causes the plunger to move member transversely to the axis of sleeve, and shaft, engaging wedgeshaped member, moving it axially of shafts and sliding clutch member on splines against the force of spring into contact with a second clutch member. Sleeve and shaft then rotate together and the slipper rotates about the axis of spindle and the axis of sleeve and. After a predetermined degree of rotation of shaft, the end of a recess in collar 46 engages the peg to disengage it from the step in recess, when the plunger moves outwardly under the influence of spring and switches off via switch the motor and via switch the recorder. If the surface of the slipper corresponds exactly to the wating end of ball the trace on recorder will be a straight line. For other forms of mating surface, the trace will be characteristic of the surface, to be compared against a reference standard. From the application GB1359688A we know a wheeled carrier which is movable on x & y axes and supports a rod movable in the z axis and downwardly urged by a controlled force from a telescopic to an extended position. A gauge comprises a housing wedged into the rod, and a shaft vertically movable in a bearing carries a screw mounted probe and is retractable against a stop ring which assists a solenoid in keeping the probe raised. The probe which is biased downwardly by a spring and its own weight automatically centres itself in a hole to be gauged and movements of the carrier and probe are automatically controlled if required from a punch tape console provided with position indicating lights. The probe may be raised by a piston and cylinder instead of by a solenoid, and is held retracted until fluid at a slightly greater pressure is exerted on the top of the piston through duct to move the probe downwardly. The probe is held retracted by a spring until overcome by pressure fluid introduced through duct to act upon the top of piston. The carrier supporting beam is protected by dust shields and similar shields are provided.

In the application GB1425105A there is exposed a solution in which a cylinder block of a rotary piston engine is rotated about its central or a first axis "X" by a gear train and by a shaft driven by a motor, and is supported by a head which may be moved longitudinally to the right by a motor driving a lead screw and returned quickly to the left by a motor driving a spiral worm and a bevel gear. A tool mounted on a head cuts the block surface into an accurate epitrochoidal surface and is supported to do this by a connecting bar or shaft eccentrically and rotatably mounted in a hollow spindle itself concentrically rotatable about a second axis "Y" by means of a gear driven by the motor. The bar has an axis "B" which is parallel to the other axes and is located on the same line as the contact of the tool with the cylinder. The bar also has a guide member which engages between pairs of rollers on an oscillating plate provided with a ournal having a third fixed axis "I". In operation, the cylinder is advanced Dy the lead screw and rotated about the first or "X" axis by the gear. The IOIIOW spindle is rotated at the same time about its own or second axis Ύ" by the motor rotating gears and simultaneously the bar is given an eccentric revolution by the rotation of the hollow spindle and the action of :he plate engaging the guide at the end of the bar. Should the tool be ^■ equired to trace or cut a two lobed cavity in the cylinder, then the gear which drives the hollow spindle must rotate about the second or "Y" axis 3t twice the speed of rotation of the gear about the first or "X" axis, and :he distance between the "Y" axis and the "Z" axis must be one third of :he distance between the "X" and "Y" axes. Other speeds and distances ^■ nust be arranged for three lobed cylinders by exchanging the gears which ire mounted on an adjustable plate and by replacing the oscillatable )late. The handstock and the block are progressively fed towards the tool jntil the entire cylinder surface has been traversed.

:rom the application GB1463533A there is known a method of and ipparatus for measuring the concentricity and roundness of features in a nechanical workpiece, e.g. valve guide holes and valve seats of internal :ombustion engines, one set of size checks is performed on different sections of a nominally cylindrical surface, a second set of checks being performed on a single nominally circular section of another surface of revolution, both sets of checks being carried out around the whole circumference of the sections, the data resulting from both sets of checks being processed to derive an indication of the concentricity error of the two surfaces, the roundness of the section of the surface of revolution being determined on the basis of a computation with the data resulting From the second set of checks. In the described embodiment, the first set Df checks is performed by feelers, the second set by feelers, a further Feeler producing a signal compensating for axial displacement of plug. Displacements detected by feelers are transformed into electric signals Bach being associated with an induction position transducer and with detecting circuits to form an electronic gauge. The head under test is nserted into a housing, lever being operated so as to raise thrust element :ogether with a second element associated with a second piston and :hereby position the head against reference elements. Actuation of a second lever is then possible, so as to raise stem into guide hole of head. ^: ailure of the stem to enter hole does not allow operation of a third lever, jnd indicates that the hole is out of tolerance in some respect, this step preventing possible jamming of plug in head. Activation of lever thereby owering the plug moving stem until arrested by a mechanical reference. A notor rotates the plug and the measurements are then carried out being eckoned on the basis of equations given in the specification.

:rom the application US4389781A there is known a coordinate measuring nachine having a vertically movable probe, the weight of which is offset )y an improved pneumatic counterbalance. The pneumatic counterbalance system is adapted to use a source of pressurized air acting upon a ball piston which is directly connected to a probe arm which supports the probe. An accumulator having a capacity large enough to insure only a small change in the counterbalanced force as the ball piston moves within its cylinder is provided. A valve is provided in the connection of the air supply to the accumulator. The valve is adjusted to provide make up air for the air which leaks past the ball piston. Preferably, the accumulator is formed as a pressurized plenum which surrounds the cylinder.

Application US4507868A exposes a coordinate measuring machine having a vertically movable probe supported from the bottom of a probe arm, the weight of which is offset by an improved pneumatic counterbalance. The pneumatic counterbalance is adapted to use a source of pressurized air acting upon a spherical piston which is connected to probe arm. Spherical piston fits with a close tolerance in cylinder. A rigid bracket is connected to the top of probe arm. Piston rod connects spherical piston to a spherical bearing in rigid bracket. A precision pressure regulator having a 'elatively small capacity is provided to insure only a small change in the :ounterbalance force as the spherical piston moves within cylinder. Regulator is adjusted to provide make up air for the air which leaks past spherical piston.

Application US4637144A exposes an apparatus for monitoring the diameters of crankpins during treatment in grinding machines in which the periphery of a selected crankpin is ground while the crankshaft rotates about an axis which is parallel to the axis of the crankpin. The decreasing

y iiameter of the crankpin is monitored by one or more sensors which are connected with a detector serving to transmit signals to the controls of the grinding machine. Retention of the sensors in continuous contact with the circulating crankpin is ensured by an elongated guide which supports the sensors and the detector and is mounted on the piston rod of a cylinder. The latter is pivotable in a holder which is reciprocably or fixedly secured to the table or to the understructure of the frame of the grinding machine. A coil spring in the cylinder biases the piston and the piston rod in a direction to maintain the forward end of the guide in continuous contact with the periphery of the circulating crankpin.

From the application US6421930B1 there is known a piston ring locating system includes a resilient ring fabricated in a generally circular configuration having a short height and a length of between about 2 inches and 5 inches with overlapping free ends. One of the ends has a slight bend there adjacent for fitting inside the opposite end. The rings are outwardly biased resiliently to allow varying the circumference of the ring as a function of the cylinder in which it is to be placed. The ring thus forms an interior surface and an exterior surface positionable within the cylinder in which it is to be placed. The ring has a top edge and a bottom edge constituting an abutment surface. Projection means extends outwardly From the exterior surface to a short distance and is adapted to be located D the upper edge of the block of the cylinder with which it is to be utilized.

The disadvantages of the solutions known to the prior art are, among Dthers, their high complexity and uncertainty of the measurement due to the susceptibility of such measuring devices to temperature fluctuations. For example: the use of a metal clamping strip makes the strip susceptible to thermal expansion caused by changes in the ambient temperature in the rooms where the measurement is carried out. Moreover, any device that employs a clamping strip is susceptible to measurement interference caused by friction.

As far as mass production of rings for the automotive machine construction industries is concerned, the ability to make fast and accurate measurement of key parameters of the rings is of critical importance. The manufacturer or designer of an engine specifies the nominal values of the parameters that must be complied with during manufacturing. Even though a piston ring is a relatively simple structure, its manufacture requires high accuracy and precision. For piston rings, the key parameters are elasticity and the stability of the profile as designed by the manufacturer. The elasticity of a piston ring is required to ensure adequate pressure of the outer surface of the ring onto a cylinder sleeve. Neither insufficient nor excessive pressure is acceptable. Insufficient pressure of the scraper ring onto the cylinder wall makes the ring leak oil From the crankcase into the combustion chamber, which and causes the formation of carbon deposits, seizure of the ring, and excessive oil consumption. For packing rings, insufficient elasticity makes the exhaust Fumes penetrate into the crankcase, which lowers the engine efficiency and power output. On the other hand, excessive pressure of the scraper ring, usually located in the lower part of the piston, causes excessive Friction against the cylinder sleeve. This prevents oil from penetrating Detween the sliding surface of the cylinder sleeve and the ring, thus making proper lubrication of the piston impossible. This, in turn, causes Dremature wear of the cylinder sleeve and the rings. Therefore, the adequate elasticity of the piston ring as per the nominal value, is one of the key parameters for this element.

In mass production it is necessary to carry out rapid and repeatable measurement by means of possibly most simple and reliable measuring devices so as to achieve repeatable measurement result.

The nature of the invention is a device for measuring the elasticity of piston rings comprising a supporting structure consisting of a base, a support and a boom, wherein the supporting structure is equipped with a digital display attached to it, and is connected on one side - with a screw mechanism equipped with a knob, an upper pressing element i.e. jaw and a guiding element - and on the other side with a lower part of the measuring mechanism, a pressure piston and a piezoelectric transducer connected to the display.

Preferably, the boom is movable.

Preferably, the height of the boom is adjustable.

Preferably, the jaw and the pressure piston have concave curvature whose radius is greater than the radius of the measured ring.

Preferably, the contact surface of the jaw and the pressure piston with the ring is made of polyamide or Teflon or bronze or other material with a low coefficient of friction.

Preferably, the top surface of the pressure piston has a ring positioning groove.

Preferably, the transducer is equipped with a wireless communication device. The device according to the invention facilitates the measurement of the elasticity of piston rings. An advantage of the measuring device according to the invention is its functionality, readout speed, repeatability and stability of the measurements, ease of use in mass production and minimal impact of friction on the readouts. The design of the device according to the invention increases the stability of the measurement, which positively affects the reliability of the measurement results. This allows the transducer to include a wireless communication device for instant transfer of readout data to a remote device i.e. a mainframe computer.

The invention is shown as an embodiment in schematic figures, in which Fig. 1 shows the front view of the device with a cross-section through the screw mechanism, Fig. 2 shows the side view of the device with a cross- section through the screw mechanism.

The invention in the embodiment according to Fig. 1 is a measuring instrument that measures radial force and which is shaped like a supporting structure consisting of a base 1 to which the lower part of the measuring mechanism 7, columns 2 are attached by screws 14, and a movable boom 3 to which a screw mechanism used to close the joint 11 is attached. The height of the boom 3 can be adjusted by moving the boom along the column 2, wherein its position can be locked with a screw 16. Fhe upper part of the measuring mechanism consists of a screw Tiechanism comprising an adjustment knob 4, pressing screw 4a equipped /vith a thread, and the upper pressing element in the form of a jaw 5, as well as a guiding member 13 which provides stable guidance of the jaw 5. The lower part of the pressing screw 4a is equipped with a groove 12 that runs along its the periphery of the screw. An elastic locking pin 4b which prevents the jaws 5 from slipping is inserted into the groove 12. The piston ring 6 is positioned between the jaw 5 and the lower part of the measuring mechanism 7. The lower part of the measuring mechanism 7 consists of a pressure piston 8 whose top surface has a concave curvature whose radius is greater than the radius of the ring 6. The top surface of the pressure piston 8 is equipped with a ring 6 positioning groove. The pressure piston 8 is connected with a piezoelectric transducer 9 located below, which converts the changes in the force exerted by the ring 6 on the pressure piston 8 to electric voltage. The transducer 9 is connected byvires 10 with a display 15 mounted on the support structure, whose Durpose is to display the value of force measured by the piezoelectric :ransducer 9. The guiding element 13 that connects the jaw 5 and the Doom 3 provides stable guidance of the jaw 5. The joint 11 of the ring 6 is Driented outside the supporting structure.

rhe measurement of the elasticity in the device according to the invention s carried out by first placing in the measured piston ring 6 in the axis of :he screw mechanism. Then both ends of the ring are forced to meet each Dther. This is done by tightening the screw mechanism via the knob 4. \utomated tightening mechanisms can be also employed for this purpose, rhen the screw mechanism is unscrewed so as to obtain the nominal required) gap at the ring 6. The size of the joint clearance is measured vith a clearance gauge known in the prior art. After obtaining the required :learance at the ring joint, as measured with the clearance gauge, the force is displayed on the digital display 15 or read by another means of communication with the device. As ring designers generally provide the value of the radial force (elasticity) in Newtons, each ring whose measured radial force (elasticity) deviates from the nominal force specified by the manufacturer is deemed faulty, if the deviation exceeds the tolerance.