Snap-on Tools Corporation

Snap-on Inc.

Snap-on Technologies, Inc.

James R Piehl

Craig F Govekar

Michael B Meeker

Michael C Putrow

Gary D Jonker

John C Sniegowski

Gary S Wollert

Robert D Braun

Thomas P Becker

Kenneth C Happ

Matthew M Crass

David D Curry

Robert O Quinn

Michael D Schoenbeck

Nancy C Rittmann Gasperi

David J Schend

Jerry W Mueckl

A wheeled, manually propelled vehicle with vertical support structure has an ergonomic handle attached to the support structure, the handle having a central section extending substantially horizontally in use and inclined sections which incline downwardly from the opposite ends of the central section and respectively terminate in curved end sections which curve toward the support structure and are integral for attachment plates for attachment to the support structure. The inclined sections facilitate grasping of the handle with an ergonomic arm position when a user is pushing the vehicle and facilitate maneuvering the vehicle around corners.

Ergonomic handle for rolling manually propelled vehicle

A linearly moving external part of a multi-cylinder internal combustion engine is contacted with a hand-held contact tachometer for producing a waveform signal which, along with a signal responsive to the ignition of each cylinder, are applied to an engine analyzer processor for display of a single engine cycle of the waveform signal on the CRT oscilloscope of the engine analyzer. The variations and amplitude of the waveform signal correspond to speed variations of the moving part over an engine cycle to give an indication of the relative power contributions of the individual cylinders. Cylinder ignition markers and cylinder zone markers are respectively displayed at the top and bottom of the screen, respectively corresponding to the cylinders in their ignition order. Each cylinder zone marker is delayed a predetermined time from its corresponding cylinder ignition marker and indicates the time period during which the engine responds to the ignition event of the corresponding cylinder.

Method and apparatus for determining relative contributions of

A digital engine analyzer has an oscilloscope display and is controlled by microprocessors operating under menu-driven stored program control. The analyzer receives analog input signals from an engine being analyzed and calculates and display spark plug burn time information derived from a single analog input signal, the data being displayed in both numerical and bar graph form. The measured burn time is the time that the ignition voltage signal is above a predetermined threshold level which is greater than the amplitude of the ringing portion of the ignition voltage signal.

Digital engine analyzer

A digital engine analyzer has an oscilloscope display and is controlled by microprocessors operating under menu-driven stored program control. The analyzer receives analog input signals from an engine being analyzed. The engine calculates and displays real-time cylinder time balance information by calculating for each cylinder the cylinder time period from the firing of that cylinder to the firing of the next cylinder, storing the cylinder time values for each cylinder for a number of successive engine cycles, averaging the time period values for each cylinder over that number of engine cycles, calculating an overall average of the cylinder averages, calculating the percentage difference between each cylinder average and the overall average and then displaying the percentage differences in both numerical and bar graph form along with the overall average value.

A digital engine analyzer has an oscilloscope display and is controlled by microprocessors operating under menudriven stored program control. The analyzer receives analog input signals from an engine being analyzed. Peak capture circuitry permits the display of a full cylinder period of a waveform, even though it contains very high frequency portions, by selectively switching between normal and high resolution modes. The circuitry samples the analog waveform at a very high rate and selects samples for display at a much slower display rate. The circuitry captures and stores the highest magnitude sample in each cylinder cycle by storing each sample only if its magnitude exceeds that of the previously stored sample. In the normal mode, at each display clock pulse the most recent sample is selected for display, irrespective of its magnitude. In the high resolution mode the stored peak value is selected for display at each display clock pulse.

Waveform peak capture circuit for digital engine analyzer

A digital engine analyzer has an oscilloscope display and is controlled by microprocessors operating under menu-driven stored program control. The analyzer receives analog input signals from an engine being analyzed, digitizes the signals, captures the digital peak ignition voltage values for each cylinder and stores only these values for each cylinder over a number of successive engine cycles, and then simultaneously displays all the stored values for any one cylinder over a number of engine cycles to provide a historical display. Each peak value is stored twice and displayed twice to provide width to the value display and effectively produce a bar graph-type display.

A digital engine analyzer has an oscilloscope display and is controlled by microprocessors operating under menu-driven stored program control. The analyzer receives analog input signals from an engine being analyzed. The analyzer is provided with a scanner interface, so that a scanner designed to read data from a vehicle on-board computer, can transfer this data to the analyzer for display on the analyzer oscilloscope. The analyzer processor, when operating in the scanner interface mode, operates under stored program control to reconfigure analyzer keyboard and soft key functions to duplicate scanner control functions, so that the scanner control functions can be effected from the analyzer.

A linearly moving external part on a multi-cylinder internal combustion engine is contacted with a hand-held rotary encoder, contact tachometer having a hollow handle in which processing circuitry is disposed for converting the rotary encoder output to a waveform signal. This signal, along with a signal responsive to the firing of the number one cylinder, are applied to an engine analyzer processor for display of a single engine cycle of the waveform signal on the CRT oscilloscope of the engine analyzer. The variations in amplitude of the waveform signal correspond to speed variations of the moving part over an engine cycle to give an indication of the relative power contributions of the individual cylinders.

The apparatus comprises a combustion sensor to sense the combustion event in an engine, and a magnetic sensor to sense top dead center. Electrical signals from the sensors are converted to two trains of pulses which are applied to a microprocessor. Under the stored program, the microprocessor determines the time between pulses in one train and converts such time into engine speed in rpm. Also, the microprocessor determines degrees of rotation between corresponding pulses in the two trains. The offset angle, which is applied to a keyboard is subtracted from the degrees of rotation to provide the timing angle. The engine speed and timing angle appear in digital displays.

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Kenosha, WI, United States of America

James R Piehl