Portable compact strip chart recorder

• US 4,141,019 A
• Filed: 05/09/1977
• Issued: 02/20/1979
• Est. Priority Date: 05/09/1977
• Status: Expired due to Term

• Current Assignee: Ryan Instruments LP (Carrier Global Corporation)
• Original Assignee: Ryan Instruments Incorporated (Carrier Global Corporation)
• Inventors: Johnson, Jerry E.
• Primary Examiner(s): Miller, Jr., George H.
• Application Number:
  US05/794,759
• Time in Patent Office: 652 Days
• Field of Search: 346/33 TP, 346/136, 346/139 R
• US Class Current: 346/136
• CPC Class Codes: G01D 15/26 operating by clockwork
• CPC Class Codes: G01D 9/00 Recording measured values

Abstract

A portable strip chart recorder is provided with a constant speed strip chart advancing drive powered from a clockworks and gear drive unit. The gear drive unit is sealed from the strip chart so that it cannot be tampered with when the strip chart is changed. The constant speed drive comprises a constant speed sprocket spool which engages sprocket holes in a strip chart running between a feed spool and a take-up spool. The feed spool is provided with a drag to allow variations in the rotational speed of the strip chart on the spool and provide tension on the chart whereas the take-up spool is provided with a slip clutch that allows the chart to be wrapped at a constant tangential speed even though the diameter of the chart on the take-up spool varies.

Claims

1. A portable compact strip chart recorder comprising:

a case having a removable cover,

a clockworks in said case,

a gear drive unit coupled to said clockworks,

a transducer for measuring an external environmental condition, a stylus, means coupling said stylus to said transducer for movement in response to movements of the transducer, and

a strip chart movement assembly including a feed spool rotatable about a first axis, a take-up spool rotatable about a second axis parallel to said first axis, a drive spool rotatable about a third axis parallel to said first and second axes, said drive spool containing equidistantly circumferentially spaced sprocket teeth, gear means coupling said drive spool to said gear drive unit for rotating said sprocket teeth at a constant speed, means coupling the drive spool to the take-up spool for synchronous rotation, said take-up spool having a chart engaging roll and slip clutch means separating the chart engaging roll from the synchronous drive coupling with the drive spool for providing variable rotation of the take-up chart engaging roll to accommodate variations in chart wrap diameter, said case being divided into a chart containing end and a probe end with the chart containing end being closed by a removable cover, an intermediate plate covering said probe end, means fastening the intermediate plate to the case, said clockworks and gear drive unit being housed within said probe end beneath said intermediate plate so that by opening said cover the strip chart only is exposed to the user.

2. A portable compact strip chart recorder comprising:

a case having a removable cover,

a clockworks in said case,

a gear drive unit coupled to said clockworks,

a transducer for measuring an external environmental condition, a multiplying linkage connected to said transducer, a stylus coupled to said linkage for movement in response to movements of the transducer, and

a strip chart movement assembly including a feed spool rotatable about a first axis, a take-up spool rotatable about a second axis parallel to said first axis, a drive spool rotatable about a third axis parallel to said first and second axes, said drive spool containing equidistantly circumferentially spaced sprocket teeth, gear means coupling said drive spool to said gear drive unit for rotating said sprocket teeth at a constant speed, means coupling the drive spool to the take-up spool for synchronous rotation, said take-up spool having a chart engaging roll and slip clutch means separating the chart engaging roll from the synchronous drive coupling with the drive spool for providing variable rotation of the take-up chart engaging roll to accommodate variations in chart wrap diameter, said strip chart movement assembly including a chart holder, at least two of said spools having axles extending laterally outwardly of said holder, said case including slots positioned relative to said gear drive unit thereby locating said axles within said slots to accurately mesh said gear means with said gear drive unit for driving the strip chart, said case being divided into a chart containing end and a probe end with the chart containing end being closed by a removeable cover, or intermediate plate covering said probe end, means fastening the intermediate plate to the case, said clockworks and gear drive unit being housed within said probe end beneath said intermediate plate so that by opening said cover the strip chart only is exposed to the user.

3. The recorder of claim 2, said feed spool including a chart supporting roll and a stationary axle and drag means coupling the chart supporting roll to the axle for allowing variable rotation of the roll to accommodate changes in diameter of the chart on the roll.