发明授权
- 专利标题: Drawing instrument
- 专利标题(中): 绘图仪器
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申请号: US817103申请日: 1977-07-19
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公开(公告)号: US4146965A公开(公告)日: 1979-04-03
- 发明人: Raymond A. Payton
- 申请人: Raymond A. Payton
- 申请人地址: GB West Midlands
- 专利权人: Helix International Limited
- 当前专利权人: Helix International Limited
- 当前专利权人地址: GB West Midlands
- 优先权: GB48257/76 19761119
- 主分类号: B43L9/20
- IPC分类号: B43L9/20 ; B43L9/24 ; B43L9/02
摘要:
A drawing instrument comprises a pair of die-cast limbs pivotally connected together to form an assembly at the inner ends thereof. A bow top has an interior hole and fork limbs having inside faces embracing the assembly of the ends. A centralizing member is held between the inner ends of the pivoted die-cast limbs. The centralizing member includes an elongated pivot receiving hole and first and second keying poles. A first die-cast keying projection is integrally formed at the inner end of a first one of the pivoted die-cast limbs. A first arcuate slot is provided in the inner end of the first pivoted die-cast limb. A second die-cast keying projection is integrally formed at the inner end of the second one of the pivoted die-cast limbs. A second arcuate slot is disposed in the inner end of the second pivoted die-cast limb. The first and second die-cast keying projections engage the second and first arcuate slots, respectively. The first and second die-cast keying projections engage the first and second keying holes in the centralizing member to key the centralizing member to the inner ends of the pivoted die-cast limbs. The centralizing member has a structural configuration to project up into the interior hole of the bow top and is further effective to press against a side wall of the interior hole when there is angular movement of one of the pivoted limbs with respect to the other pivoted limb. Consequently, the structural configuration of the centralizing member causes the bow top to turn and keep central. Stop means engageable with the inner ends of the pivoted limbs are effective to act against the angular opening out movement of the pivotal limbs beyond a predetermined angular limit. Thus, the two die-cast projections cannot bear against the ends of the respective arcuate recesses or slots before the stop means on the bow top bear against the inner ends of the die-cast limbs. BACKGROUND OF THE INVENTION
公开/授权文献
- USD339972S Hammer 公开/授权日:1993-10-05