Walk behind self-propelled crawler snowplow

• US 6,688,022 B2
• Filed: 09/06/2002
• Issued: 02/10/2004
• Est. Priority Date: 03/29/2000
• Status: Expired due to Fees

• Current Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Original Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Inventors: Takeishi, Masanori, Kuroiwa, Kenji, Hanafusa, Jitsumi
• Primary Examiner(s): PEZZUTO, ROBERT ERIC
• Application Number:
  US10/236,415
• Publication Number:
  US 20030005603A1
• Time in Patent Office: 522 Days
• Field of Search: 372/44, 372/42, 372/46, 372/48, 372/52--57, 372/66, 180/656, 192/34, 192/3.58, 192/56, 192/150, 474/101-110, 474/136, 474/138, 748/66
• US Class Current: 37/257
• CPC Class Codes: F16D 2027/002 Electric or electronic circuits relating to actuation of electromagnetic clutches
• CPC Class Codes: F16D 2500/1022 Electromagnet
• CPC Class Codes: F16D 2500/10475 Magnetic field, e.g. electro-rheological, magnetisable particles
• CPC Class Codes: F16D 2500/3024 Pressure
• CPC Class Codes: F16D 2500/3026 Stroke
• CPC Class Codes: F16D 2500/3146 input from levers
• CPC Class Codes: F16D 2500/7041 Position
• CPC Class Codes: F16D 2500/70418 Current
• CPC Class Codes: F16D 2500/7042 Voltage
• CPC Class Codes: F16D 27/112 with flat friction surfaces, e.g. discs
• CPC Class Codes: F16D 48/00 External control of clutches
• CPC Class Codes: F16D 48/064 Control of electrically or electromagnetically actuated clutches F16D48/062, F16D48/068 take precedence
• CPC Class Codes: F16H 35/10 Arrangements or devices for absorbing overload or preventing damage by overload for screw mechanisms F16H25/2021

Abstract

A walk behind self-propelled crawler snowplow includes a snowplow mechanism driven by an engine via a belt drive power transmission mechanism, and an overload protection device associated with the belt drive power transmission mechanism for protecting the engine against overload. The overload protection device comprises a tension sensor for detecting the tension in an endless belt and generating an electric overload signal to disengage an electromagnetic clutch in the belt drive power transmission mechanism when a belt tension greater than a predetermined value is detected.

Claims

1. A machine comprising:

an engine;

a transmission having a pair of pulleys, a belt entrained over the pulleys, and an electromagnetic clutch for selectively engaging and disengaging one of the pulleys with an output shaft of the engine;

a driven mechanism driven by the engine via the transmission; and

a belt tension detecting device for detecting belt tautness associated with an overload condition and supplying an overload signal to effect disengagement of the electromagnetic clutch when the overload condition is detected.

2. A machine according to claim 1;

wherein the belt tension detecting device comprises a tension roller, bias means for applying a bias force to urge the tension roller against an outer circumferential surface of the belt to cause a portion of the belt between the pulleys to flex inwardly, and a detector unit for detecting displacement of the tension roller in a direction outward of the belt when the belt is stretched substantially due to the overload condition.

3. A machine according to claim 2;

wherein the belt tension detecting device further comprises a pivotally movable lever having a first end on-which the tension roller is rotatably mounted, and the detector unit comprises an electric switch having an actuator held in contact with a second end of the lever opposite the first end, the actuator being movable in response to pivotal movement of the lever to turn on and off the switch.

4. A machine according to claim 1;

wherein the driven mechanism comprises a snowplow mechanism having a rotating shaft connected to one of the pulleys, an auger and a blower connected in driven relation to the rotating shaft.

5. A machine according to claim 1;

wherein the pair of pulleys comprises a driven pulley releasably coupled with the output shaft of the engine, and a driven pulley connected to the rotating shaft.

6. A machine according to claim 1;

wherein the detector unit comprises an electric switch electrically connected with the electromagnetic clutch and having an actuator held in contact with the opposite end of the lever, the actuator being movable in response to pivotal movement of the lever to turn on and off the switch.

7. A machine according to claim 1;

wherein the clutch comprises an electromagnet non-rotatably mounted to the frame, a disc connected to the output shaft of the engine to undergo rotation therewith, and a clutch plate directly connected to one of the pulleys so as to confront a friction surface of the disc with a small gap therebetween.

8. A machine according to claim 7;

wherein the electromagnet is normally de-energized so that the clutch is normally in a disengaged state, and the clutch plate is attracted to the disc when the electromagnet is energized to thereby engage the clutch so that the one pulley is connected to the output shaft of the engine via the clutch and power from the engine is transmitted to the driven mechanism.