Electrically powered gardening tool

• US 9,357,711 B2
• Filed: 07/02/2013
• Issued: 06/07/2016
• Est. Priority Date: 07/04/2012
• Status: Active Grant

• Current Assignee: Makita Corporation
• Original Assignee: Makita Corporation
• Inventors: Kato, Kazuya, Koide, Yuki
• Primary Examiner(s): PRONE, JASON D
• Application Number:
  US13/933,370
• Publication Number:
  US 20140007717A1
• Time in Patent Office: 1,071 Days
• Field of Search: 30208-210, 30215-220
• US Class Current: 1/1
• CPC Class Codes: A01G 2003/0461 with reciprocating knives
• CPC Class Codes: A01G 3/053 motor-driven
• CPC Class Codes: A01G 3/067 Motor-driven shears for lawns
• CPC Class Codes: F16H 21/18 Crank gearings; Eccentric gearings
• CPC Class Codes: Y10T 74/18248 Crank and slide

Abstract

An electrically powered gardening tool of the type which includes a speed-reduction gear mounted in place to be driven by operation of an electric motor, a crank-cam in the form of overlapped eccentric disk plates fixed to a bottom surface of the speed-reduction gear by means of connecting pins for rotation therewith, and a pair of relatively reciprocating shear blades assembled with the eccentric disk plates. In the gardening tool, an elastic bushing is disposed in a mounting hole formed in the speed-reduction gear or each eccentric disk plate of the crank-cam for engagement with the connecting pins fixed to the eccentric disk plate or the speed-reduction gear, and a stopper is provided to restrict deformation of the elastic bushing caused by load applied to the crank-cam.

Claims

1. An electrically powered gardening tool comprising:

a speed-reduction gear rotatably mounted to a bottom surface of a motor housing and driven by an electric motor housed within the motor housing;

a crank-cam defined by overlapped eccentric disk plates connected to a bottom surface of the speed-reduction gear; and

a pair of reciprocating shear blades operatively connected to the eccentric disk plates, wherein

one of the eccentric disk plates and the speed-reduction gear further includes connecting pins that connect the one of the eccentric disk plates and the speed-reduction gear to the other of the eccentric disk plates and the speed-reduction gear,

elastic bushings are disposed in mounting holes provided in the other of the eccentric disk plates and the speed-reduction gear,

the connecting pins are received in the mounting holes to engage with the elastic bushings so as to cause the eccentric disk plates to rotate with the speed-reduction gear, and

stoppers are provided in the mounting holes and are configured to abut against a surface of the mounting holes to restrict deformation of the elastic bushings caused by a load applied to the eccentric disk plates.

2. An electrically powered gardening tool as claimed in claim 1, wherein said stoppers are cylindrical stoppers smaller in diameter than a diameter of each of said elastic bushings and are coupled with said connecting pins in the mounting holes.

3. An electrically powered gardening tool as claimed in claim 1, wherein said stoppers are cylindrical stoppers, each cylindrical stopper having an inner diameter that is larger than an outer diameter of each of said connecting pins and said stoppers are engaged with an inner surface of each of said mounting holes.

4. An electrically powered gardening tool comprising:

a speed-reduction gear rotatably mounted to a bottom surface of a motor housing and driven by an electric motor housed within the motor housing;

a crank-cam defined by overlapped eccentric disk plates connected to a bottom surface of the speed-reduction gear; and

a pair of reciprocating shear blades operatively connected to the eccentric disk plates, wherein

one of the eccentric disk plates and the speed-reduction gear further includes connecting pins that connect the one of the eccentric disk plates and the speed-reduction gear to the other of the eccentric disk plates and the speed-reduction gear,

elastic bushings are disposed in mounting holes provided in the other of the eccentric disk plates and the speed-reduction gear,

the connecting pins are received in the mounting holes to engage with the elastic bushings so as to cause the eccentric disk plates to rotate with the speed-reduction gear,

the connecting pins include a step defining a small diameter portion and a large diameter portion with a diameter larger than a diameter of the small diameter portion, the small diameter portion having a diameter smaller than a diameter of each of said elastic bushings and the large diameter portion of each of the connecting pins together define stoppers, and

the stoppers are provided in the mounting holes and are configured to abut against a surface of the mounting holes to restrict deformation of the elastic bushings caused by a load applied to the eccentric disk plates.

5. An electrically powered gardening tool comprising:

a speed-reduction gear rotatably mounted to a bottom surface of a motor housing and driven by an electric motor housed within the motor housing, a bottom surface of the speed-reduction gear including stopper pins fixed thereto;

a crank-cam defined by overlapped eccentric disk plates connected to the bottom surface of the speed-reduction gear, the eccentric disk plates including engagement holes; and

a pair of reciprocating shear blades operatively connected to the eccentric disk plates, wherein

one of the eccentric disk plates and the speed-reduction gear further includes connecting pins that connect the one of the eccentric disk plates and the speed-reduction gear to the other of the eccentric disk plates and the speed-reduction gear,

elastic bushings are disposed in mounting holes provided in the other of the eccentric disk plates and the speed-reduction gear,

the connecting pins are received in the mounting holes to engage with the elastic bushings so as to cause the eccentric disk plates to rotate with the speed-reduction gear,

the stopper pins passing through the engagement holes of the eccentric disk plates, the engagement holes of the eccentric disk plates each having a diameter that is larger than a diameter of each of the stopper pins and thereby defining clearances, the clearances each have a thickness smaller than a thickness of each of said elastic bushings, and

the stopper pins are provided to restrict deformation of the elastic bushings caused by a load applied to the eccentric disk plates.

6. An electrically powered gardening tool comprising:

a speed-reduction gear rotatably mounted to a bottom surface of a motor housing and driven by an electric motor housed within the motor housing;

a crank-cam defined by overlapped eccentric disk plates connected to a bottom surface of the speed-reduction gear; and

a pair of reciprocating shear blades operatively connected to the eccentric disk plates, wherein

one of the eccentric disk plates and the speed-reduction gear further includes connecting pins that connect the one of the eccentric disk plates and the speed-reduction gear to the other of the eccentric disk plates and the speed-reduction gear,

elastic bushings are disposed in mounting holes provided in the other of the eccentric disk plates and the speed-reduction gear,

the connecting pins are received in the mounting holes to engage with the elastic bushings so as to cause the eccentric disk plates to rotate with the speed-reduction gear, and

a diameter portion of each of said mounting holes defines stoppers that are provided to restrict deformation of the elastic bushings caused by a load applied to the eccentric disk plates, the diameter portion of each of said mounting holes being larger than a diameter of each of said connecting pins and smaller than a diameter of each of said elastic bushings.