Heavy duty stapler

Details Heavy duty stapler Heavy duty stapler

2002-02-20

2004-08-17

Gerrity, Stephen F. (Department: 3721)

Elongated-member-driving apparatus

With means to move or guide member into driving position

Including supply magazine for constantly urged members

C227S127000, C227S154000, C227S120000, C227S134000

Reexamination Certificate

active

06776321

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to staplers and, more specifically, to heavy-duty staplers.
BACKGROUND OF THE INVENTION
Heavy duty staplers typically include a base, a cartridge assembly pivotally mounted to the base, and a lever assembly including a lever arm that will provide a force to the cartridge assembly to drive a staple through a stack of sheets. The lever arm is commonly pivotally mounted to either the cartridge assembly or the base.
There are many characteristics of a heavy-duty stapler that define the quality of the stapler. For example, one important characteristic is the stapler's ability to consistently drive a staple through a thick stack of sheets without staple failure and without jamming the magazine. Another characteristic is the amount of force required to use the stapler. It can be appreciated that it would be desirable to produce a stapler that can consistently drive staples through a stack of sheets without failure and with a reduced force applied to the lever arm.
SUMMARY OF THE INVENTION
The present invention provides a stapler that is designed to require less force on the lever arm in order to drive a staple through a stack of sheets. This is accomplished by the relative positioning between the pivot points of the cartridge assembly and lever assembly, and the connection between the cartridge assembly and the lever assembly.
More specifically, the present invention provides a stapler comprising a base defining a horizontal plane, a cartridge assembly coupled to the base at a cartridge attachment point, the cartridge assembly including a ram, and a lever arm pivotally coupled to the base at a lever pivot axis. The lever arm includes a grip at one end for receiving a manual input from a user, and the lever arm is coupled to the ram at a ram input in order to provide a drive force. The stapler includes an inherent force factor, calculated as the horizontal distance from the lever pivot axis to the end of the lever arm divided by the horizontal distance from the lever pivot axis to the ram input, of is at least 3.8 (preferably at least 3.9).
In one embodiment, the cartridge assembly includes a cartridge housing, and the ram is slidable relative to the cartridge housing along a ram axis. In the static position, the lever arm defines an effective lever axis that is at least about 65° (preferably at least about 70° and most preferably about 72.4°) offset from the ram axis. When stapling, the effective lever axis is greater than about 95° (preferably at least about 100° and most preferably about 103°) when the lever arm is compressed to the fully stapled position.


REFERENCES:
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patent: 1998328 (1935-04-01), Mckinnie
patent: 5492261 (1996-02-01), Chi
patent: 5639007 (1997-06-01), Nakamura
patent: 5758813 (1998-06-01), Kikuchi et al.
patent: 5979736 (1999-11-01), Edeholt
patent: 6179193 (2001-01-01), Nagai
patent: 6244491 (2001-06-01), Kandasamy et al.
Prior art Swingline 900XD, photo numbers 1496, 1497, and 1498.
Prior art Swingline 39 Heavy Duty Stapler, photo numbers 1501, 1502, and 1503.
Prior art Bostitch Model B300HDS, photo numbers 1505, 1506, and 1507.
Prior art Bostitch Model B310HDS, photo numbers 1511, 1512, and 1513.
Prior art Swingline 390, photo numbers 1515, 1516, and 1517.
Prior art Bostitch Model 00540, photo numbers 1520, 1521, and 1522.
Prior art Bostitch Model 136, stock No. 73136, photo numbers 1525, 1526, and 1527.
Prior art Swingline 390, photo numbers 1530, 1531, and 1532.
Prior art Swingline 390, photo numbers 1533, 1534, and 1535.
Prior art Swingline 413, photo numbers 1536, 1537, and 1538.
Prior art Acco Brands staplers: Acco Brands Fact Book 2001 Catalog p. 187.

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