Claims
- 1. In a manual paper sheet punch having a base, an elongated flap pivotal about a flap axis, which flap has an upper cam surface, the improvement comprising:
- a) said flap having a first portion adjacent the flap axis and a second portion remote from the flap axis, which second portion includes said upper cam surface;
- b) a plurality of spaced apart pins for punching paper sheets, said pins being positioned below the flap for engagement with said first portion of said flap at a pin engaging location defined by said first portion; and
- c) cam lever means mounted on a lever axis fixed on the punch, said axis lever extending perpendicular to said flap axis, said cam lever means including:
- i) a first surface spaced from said lever axis to which a punch operating force is applied to move said lever means, and
- ii) a second surface disposed between said lever axis and said first surface and positioned for cam engagement with said upper cam surface of the second portion of the flap,
- whereby movement of the lever means about its lever axis by said force applied to said lever means causes the flap to pivot about said flap axis to punch paper sheets.
- 2. The paper punch of claim 1 in which the base has a rectangular area and cam lever means is positioned within such area as viewed from above.
- 3. The paper punch of claim 1 in which the flap has a convex surface and each of said pins has a convex surface, which flap convex surface and pin convex surface engage during punching.
- 4. The manual punch of claim 1, wherein:
- a) said first portion of said flap is spaced from the flap axis by a first distance and said second portion is spaced from the flap axis by a second distance greater than said first distance;
- b) said plurality of spaced apart pins are disposed below said flap for engagement by said first portion of said flap at said pin engaging location under a first force for punching paper; and
- c) said cam lever means is mounted on said lever axis with said second portion of said flap and said second surface of said lever means being spaced from said lever axis by a third distance and with said first surface of said lever means being spaced from said lever axis by a forth distance greater than said third distance, said cam lever means being fixed on the punch for cam engagement of said second surface with the upper cam surface of the second portion of the flap upon movement of the lever means about its lever axis in response to a second force applied to said first surface of said lever means to cause the flap to pivot to punch paper sheets, with the first, second, third and fourth distances being related to each other to produce said first force against the punch pins at a level over eight times said second force applied to the lever means.
Parent Case Info
This is a continuation of application Ser. No. 08/270,186, filed Jul. 1, 1994, now abandoned.
US Referenced Citations (14)
Foreign Referenced Citations (2)
Number |
Date |
Country |
2021935 |
May 1970 |
DEX |
136042 |
Dec 1919 |
GBX |
Continuations (1)
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Number |
Date |
Country |
Parent |
270186 |
Jul 1994 |
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