Gear mechanism and tape player using gear mechanism

• US 5,570,852 A
• Filed: 02/28/1994
• Issued: 11/05/1996
• Est. Priority Date: 03/02/1993
• Status: Expired due to Fees

• Current Assignee: Kabushiki Kaisha Shinkawa
• Original Assignee: Kabushiki Kaisha Shinkawa
• Inventors: Ikuta, Tadahiro
• Primary Examiner(s): DARLING, JOHN PATRICK
• Application Number:
  US08/203,051
• Time in Patent Office: 981 Days
• Field of Search: 242/356, 242/356.3, 242/356.4, 242/356.5, 242/356.7, 360/96.3, 74/384, 74/462
• US Class Current: 242/356
• CPC Class Codes: F16H 2055/0893 for parallel shaft arrangement of toothed members
• CPC Class Codes: F16H 3/34 with gears shiftable otherwise than only axially
• CPC Class Codes: F16H 55/0806 Involute profile
• CPC Class Codes: F16H 55/088 with corrections on tip or foot of the teeth, e.g. addendum relief for better approach contact
• CPC Class Codes: G11B 15/44 Speed-changing arrangements; Reversing arrangements; Drive transfer means therefor

Abstract

Preselected teeth of a gear tooth are truncated by removing their radially outermost ends. Thus, whenever teeth that should mesh become misaligned, the truncation allows the teeth to quickly return to their proper meshing. This reduces the sound generated by nonmeshing teeth. In a tape player using gears having preselected truncated teeth, an idler arm carries an idler gear at its free end and is pivotal into first, neutral, and second positions. At low speed operation, when a cassette is in the player, a pair of driving gears are not intermeshed, and the first position of the idler gear causes recording or playing back and the second position causes rewinding. At high speed operation, when no cassette is in the tape player, the driving gears are intermeshed, and the first and second positions of the idler arm cause fast forwarding and rewinding, respectively.

Claims

1. A gear mechanism comprising a fixed-shaft gear rotated at a fixed position and a movable gear which is movable toward and away from said fixed-shaft gear so as to be freely engaged with and separated therefrom, comprising:

a portion from a root circle to a tip circle of each tooth of said fixed-shaft gear and movable gear being formed of a constant curvature; and

said fixed-shaft gear and said movable gear being selectively provided with truncated teeth intermittently placed with full-size teeth, each truncated tooth having a tip portion from the vicinity of a pitch circle to the tip circle cut off.

2. A tape player comprising:

a movably mounted idler gear which is selectively movable between a first reel block gear and an intermediate gear so as to freely engage with and separate from said first reel block gear and said intermediate gear, said first reel block gear and said intermediate gear being driven by shifting engagement of said movably mounted idler gear between a first and a second position;

a first and a second driving gear;

a second reel block gear;

a portion from a root circle to a tip circle of each tooth of said first and second driving gears, first and second reel block gears, said movably mounted idler gear, and said intermediate gear is formed of a constant curvature; and

at least one of said driving gears of said first and second driving gears or reel block gears of said first and second reel block gears or said movably mounted idler gear or said intermediate gear is provided with truncated teeth intermittently dispersed among full-size teeth, each truncated tooth having a tip portion from a vicinity of a pitch circle to the tip circle cut off.

3. The tape player of claim 2, further comprising:

said intermediate gear having a fixed shaft positioned between said movably mounted idler gear and said second reel block gear so as to be able to engage with said second reel block gear;

said movably mounted idler gear positioned between said intermediate gear and said first reel block gear so as to be able to engage with said intermediate gear and said first reel block gear;

whereby directions of the tape feed are switched by shifting engagement of said movably mounted idler gear.

4. A tape player, comprising;

an idler arm mounted for pivotal movement between a first, a neutral, and a second position;

an idler arm idler gear rotatably mounted at a free end of said idler arm;

a first and a second driving gear, said second driving gear being movably mounted;

a first large reel block gear and a first small reel block gear coaxially mounted therewith;

a second large reel block gear and a second small reel-block gear coaxially mounted therewith;

a movably mounted idler gear;

a fixed shaft intermediate gear;

said first position of said idler arm causing said idler arm idler gear to meshingly engage said first small reel block gear and said first driving gear;

said first position of said idler arm causing said idler arm idler gear to meshingly engage said first driving gear;

said second position of said idler arm causing said movably mounted idler gear to meshingly engage said second small reel block gear and said second driving gear;

said second position of said idler arm causing said idler arm idler gear to disengage from said first driving gear;

whereby said first and second positions of said idler gear effect fast forwarding and rewinding, respectively, when said first and second driving gears are intermeshed with one another.

5. A tape player, comprising:

an idler arm mounted for pivotal movement between a first, a neutral, and a second position;

an idler arm idler gear rotatably mounted to a free end of said idler arm;

a first and a second driving gear, said second driving gear being movably mounted;

a third driving gear coaxially mounted and conjointly rotatable with said first driving gear;

a first large reel block gear and a first small reel block gear coaxially mounted therewith;

a second large reel block gear and a second small reel block gear coaxially mounted therewith;

a movably mounted idler gear;

a fixed shaft intermediate gear;

said first position of said idler arm causing said movably mounted idler gear to meshingly engage said third driving gear and said first large reel block gear;

said second position of said idler arm causing said movably mounted idler gear to meshingly engage said third driving gear and said fixed shaft intermediate gear;

said fixed shaft intermediate gear being intermeshed with said second large reel block gear;

whereby said first and second positions of said idler arm effect replay or recording and rewinding, respectively, when said first and second driving gears are disengaged from one another.