Mechanical guns and projectors – Spring – Bow
Reexamination Certificate
2000-07-24
2001-03-27
Ricci, John A. (Department: 3712)
Mechanical guns and projectors
Spring
Bow
C124S040000
Reexamination Certificate
active
06205990
ABSTRACT:
BACKGROUND OF THE INVENTION
The field of the invention pertains to crossbows and crossbow trigger mechanisms. The invention relates more particularly to an anti-dry fire mechanism for crossbows, wherein an arrow contacting surface operates a hook-type catch to engage and prevent operation of a trigger mechanism.
Various types of trigger mechanisms have been specifically developed for use in crossbows. Many, if not most, of these crossbow trigger mechanisms are designed with built-in safety mechanisms which prevent accidental discharge of an arrow. However, these conventional safety mechanisms are typically not designed for preventing the release of a cocked but unloaded bowstring, i.e. when an arrow is not positioned for discharge. This situation, commonly known as “dry fire”, can cause damage to the crossbow or be potentially hazardous to the user. In an effort to prevent the occurrence of dry fire situations, various dry fire prevention devices have been developed for crossbows which disable operation of the crossbow trigger mechanism while an arrow is not positioned to be discharged.
For example, in U.S. Pat. No. 5,085,200 a self-actuating, dry-fire prevention safety device for a crossbow is shown having a stop block
30
which pivotally operates to block forward movement of a safety assembly block plate
22
when an arrow is not positioned to be discharged. It does so by abutting a blocking portion
34
of the stop block
30
against a rounded operating pin
24
of the safety assembly block plate
22
. The disadvantage of this arrangement is the limited efficacy and unreliability of a blocking impedance as opposed to impedance by catch-engagement. While exact alignment of the blocking component
34
with the operating pin
24
would effectively prevent dry fire (FIG.
5
), the slightest variation in pivot angle of the stop block
30
may cause the blocking engagement to slip and thereby enable dry fire.
And in U.S. Pat. No. 5,598,829 a crossbow dry fire prevention device is shown having a string catch member with an arrow contacting surface which cause the string catch member to be moved out of the string catching position when an arrow is placed in the firing position. When the bowstring is cocked but an arrow is not in place, the string catch member is urged into the release path of the bowstring. In this manner, the string catch member functions to catch the inadvertently released bowstring to prevent dry fire. However, this arrangement does not operate to inhibit operation of the trigger mechanism. Notwithstanding the absence of an arrow, actuation of the trigger mechanism will release the cocked bowstring from the sear, only to be caught by the string catching member.
Similar to the 839 patent, a crossbow is shown in U.S. Pat. No. 5,884,614 also having a dry fire prevention mechanism which operates to block the release passage of a bowstring when an arrow is not in place. In particular, a safety latch positioned above the release passage is urged downward into the release passage by means of a safety latch spring. This arrangement, however, also does not inhibit operation of the trigger mechanism. While inadvertent release of the unloaded bowstring will not dry fire, the bowstring must be cocked again and reset onto the sear before successful operation may take place.
In summary, it is therefore desirable to provide a dry fire prevention safety mechanism for use on crossbows which not only blocks movement of the trigger mechanism, but directly catches a part of the trigger mechanism to prevent operation of the crossbow trigger mechanism when no arrow is positioned for discharge. Moreover, a dry fire prevention mechanism having a minimal number of moving parts, e.g. a single moving arm, would provide simplified operation, as well as reduce manufacturing costs compared to complex, multi-link dry fire prevention safety systems.
BRIEF SUMMARY OF THE INVENTION
It is an object of the present invention to provide a reliable dry fire prevention mechanism for crossbows wherein the crossbow trigger mechanism is made inoperable while an arrow is not positioned for discharge.
It is a further object of the present invention to provide a simple and efficient dry fire mechanism for crossbows having a one-piece catch arm which directly catch-engages the trigger without any wasted movement or the need for additional links or intermediate components.
It is a still further object of the present invention to provide a dry fire mechanism for crossbows which may be manufactured in a cost-effective manner by conventional manufacturing methods.
The present invention is for a safety mechanism for preventing dry fire of a crossbow. The crossbow is of the type having a bow mounted on a crossbow stock and a trigger mechanism which releases a bowstring to discharge an arrow. The safety mechanism comprises a catch arm which is pivotally connected to the crossbow stock. The catch arm has a first catch element, such as a hook, at one end for releasably engaging a second catch element, such as a catch pin, of the trigger mechanism. Additionally, the catch arm has an arrow contacting surface which pivots the first catch element out of engagement with the second catch element when an arrow is positioned to be discharged. And finally the safety mechanism comprises resiliently biasing means for urging the first catch element to releasably engage the second catch element of the trigger mechanism when no arrow is positioned to be discharged, thereby preventing dry fire while an arrow is not in place.
REFERENCES:
patent: 4192281 (1980-03-01), King
patent: 4721092 (1988-01-01), Waiser
patent: 4877008 (1989-10-01), Troubridge
patent: 5085200 (1992-02-01), Horton-Corcoran et al.
patent: 5598829 (1997-02-01), Bednar
patent: 5884614 (1999-03-01), Darlington et al.
Ricci John A.
Tak James S.
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