1. Field of the Invention
The present invention relates to a retractable blade knife, especially to a retractable blade knife that has a blade that must be moved manually a certain distance and then a spring inside the retractable blade knife will help the blade to move to be opened.
2. Description of the Prior Arts
A sliding blade knife has a blade and a handle and may be a retractable blade knife, switchblade knife or the like. The blade is retracted into the handle making the sliding knife popular since it can be safely and conveniently stored and carried for outdoor activities and work.
A conventional retractable blade knife, like utility knife, further comprises a locking mechanism. The blade is mounted in the handle. The locking mechanism is mounted between the handle and the blade. The blade must be pushed to be retracted or extended. The locking mechanism locks the blade in open and closed positions and prevents the blade from being retracted or extended accidentally. However, the blade of the conventional retractable blade knife must be moved manually to entirely open or entirely closed to activate the locking mechanism. Therefore, retracting or extending the blade is slow and inconvenient.
A conventional switchblade knife further comprises a spring mechanism and a release mechanism. The spring mechanism is mounted between the handle and the blade and ensures the blade is fully opened automatically when released from the release mechanism, generally very quickly. However, the switchblade knife is restricted by laws and is restricted to some people only in some countries. Therefore, the switchblade knife is not commonly used in ordinary people.
To overcome the shortcomings, the present invention provides a retractable blade knife with an opening assisted mechanism to mitigate or obviate the aforementioned problems.
The main objective of the present invention is to provide a retractable blade knife with an opening assisted mechanism that has a handle, a blade being mounted in the handle, an extending assembly being mounted between the blade and the handle. The blade has a spine edge and at least one detent formed at the spine edge. The extending assembly has a positioning frame, a slider being mounted beside the positioning frame and being attached to the blade and a spring being attached to the positioning frame and the slider. The positioning frame has a resilient rod selectively abutting the spine edge of the blade and the proximal end of the blade.
The blade should be pushed manually a certain distance to allow the spine edge of the blade to push a rear end of the resilient rod outwardly. When the detent of the blade and a lock protrusion of the slider both depart from the resilient rod of the positioning frame, the spring may further pull the slider to move together with the blade to stretch out the blade. Thus, the spring of the extending assembly helps the blade to be extended quickly with the spring and also prevents the blade from being retracted or extended accidentally with the resilient rod of the positioning frame abutting the blade. Therefore, the retractable blade knife with an opening assisted mechanism is used safely and conveniently.
Other objectives, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.
With reference to
The handle (10) may be formed from two casings (11A, 11B) and has a front end, a rear end, a back surface, an open surface, a blade hole (13), a positioning hole (14), a guiding slot (15) and a sliding slot (16). The casings (11A, 11B) correspond to and are mounted to each other. Each casing (11A, 11B) has a front end, a rear end, a back surface and an open surface. The blade hole (13) is formed through the front end of the handle (10) and may be formed through the front end of one of the casings (11A). The positioning hole (14) is formed through the rear end of the handle (10) and may be formed through the rear ends of the casings (11A, 11B). The guiding slot (15) is formed through the back surface of the handle (10) and may be formed through the back surface of one of the casings (11A). The sliding slot (16) is formed through the open surface of the handle (10) and may be formed through the open surface of one casing (11A).
The blade (20) is mounted movably in the handle (10), may be mounted between the casings (11A, 11B) and has a proximal end, a spine edge, a closed surface, an open surface and at least one detent. The open surface of the blade (20) is visible through the sliding slot (16) of the handle (10). Each detent is formed on the spine edge of and near the proximal end of the blade (20), is sloping and may be a first step (21) and a second step (22).
The stationary frame (30) is mounted between the casings (11A, 11B) of the handle (10) to allow the casings (11A, 11B) to be mounted securely to one another through the stationary frame (30) and has a rear edge, an elongated hole (31), a rod recess (32) and a positioning recess (33). The elongated hole (31) is formed through the stationary frame (30), corresponds to the sliding slot (16) of the casing (11A) of the handle (10) and has a back edge. The rod recess (32) is formed in the back edge of the elongated hole (31) of the stationary frame (30). The positioning recess (33) is formed in the rear edge of the stationary frame (30) and corresponds to the positioning hole (14) of the handle (10).
With further reference to
The positioning frame (41) is mounted in the handle (10) beside the closed surface of the blade (20) and has an open surface, a closed surface, a rear edge, a front end, a back edge, a sliding slot (411), a positioning recess (412), a spring mount (413) and a resilient rod (414). The open surface faces the closed surface of the blade (20). The sliding slot (411) is formed through the positioning frame (41) and corresponds to the sliding slot (16) of the handle (10). The positioning recess (412) is formed in the rear edge of the positioning frame (41), corresponds to the positioning hole (14) of the handle (10) and the positioning recess (33) of the stationary frame (30). The spring mount (413) is formed on and protrudes transversely from the front end of the positioning frame (41) toward the closed surface of the positioning frame (41). The resilient rod (414) is mounted on the back edge of the positioning frame (41) and has a rear end and a front end. The rear end of the resilient rod (414) selectively abuts the spine edge of the blade (20). The front end of the resilient rod (414) selectively abuts the proximal end of the blade (20) and has a side edge and an abutting protrusion (415). The abutting protrusion (415) is formed on the side edge of the front end of the resilient rod (414).
With further reference to
The spring (43) is connected respectively to the positioning frame (41) and the slider (42) and has two ends. The ends of the spring (43) are attached respectively to the positioning frame (41) and the slider (42) and may be attached respectively to the spring mounts (413, 422) of the positioning frame (41) and the slider (42).
The outer fastener (70) is mounted through the positioning hole (14) of the handle (10), is mounted securely in the positioning recesses (33, 142) of the stationary frame (30) and the positioning frame (41) to hold the stationary frame (30) and the positioning frame (41) firmly in the handle (10).
The inner fasteners (80) are mounted movably through the sliding slots (421, 411) of the slider (42) and the positioning frame (41) and are attached securely to the closed surface of the blade (20). Therefore, the blade (20) may move along the sliding slot (421) of the slider (42), and the blade (20) and the slider (42) may move along the sliding slot (411) of the positioning frame (41) together.
With further reference to
Therefore, with further reference to
The unlock assembly (60) is mounted on the open surface of the blade (20) near the proximal end, protrudes out of the sliding slot (16) of the handle (10) and has a thumb stud (61) and an unlock bracket (62).
The thumb stud (61) is attached to the open surface of the blade (20) and protrudes out of the sliding slot (16) of the handle (10) and has a closed surface, a belly surface and a pivot protrusion (611). The closed surface of the thumb stud (61) faces the open surface of the blade (20). The pivot protrusion (611) is formed on the closed surface of the thumb stud (61). When the thumb stud (61) is pushed to move along the sliding slot (16) of the handle (10), the blade (20) and the slider (42) may move along the sliding slot (411) of the positioning frame (41) simultaneously.
The unlock bracket (62) is mounted between the open surface of the blade (20) and the thumb stud (61), is mounted pivotally on the thumb stud (61) and has a sliding wall, a limiting wall (623), a pivot hole (622) and an unlock protrusion (621). The sliding wall of the unlock bracket (62) is disposed slidably on the blade (20) and has a back edge. The limiting wall (623) of the unlock bracket (62) is formed transversely on the sliding wall of the unlock bracket (62) and corresponds to and is selectively pushed by the belly surface of the thumb stud (61). The pivot hole (622) is formed through the sliding wall of the unlock bracket (62) and is mounted around the pivot protrusion (611) of the thumb stud (61) to allow the unlock bracket (62) to pivot relative to the thumb stud (61). The unlock protrusion (621) is formed on the back edge of the sliding wall of the unlock bracket (62) and selectively abuts the resilient rod (414) of the positioning frame (41).
With reference to
With further reference to
With further reference to
With further reference to
The retractable blade knife with an opening assisted mechanism as described has the following advantages. The blade (20) must be moved manually a certain distance to allow the sloping detents of the blade (20) to push the rear end of the resilient rod (414) outwardly gradually. Until the detents of the blade (20) and the lock protrusion (423) of the slider (42) both depart from and may pass through the rear end of resilient rod (414), the spring (43) of the extending assembly (40) serves to complete movement of the blade (20) without application of further outside forces. Thus, the extending assembly (40) helps the blade (20) to be extended quickly with the spring (43) and also prevents the blade (20) from being retracted and extended accidentally with the resilient rod (414) of the positioning frame (41) abutting the blade (20). Therefore, the retractable blade knife with an opening assisted mechanism is used safely and conveniently.
Even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and features of the invention, the disclosure is illustrative only. Changes may be made in the details, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.
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Number | Date | Country | |
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20090235534 A1 | Sep 2009 | US |