Abstract
The present invention discloses a utility knife, which includes a housing that has an internal chamber; a blade carrier for carrying a single blade; a locking piece for locking the single blade in the blade carrier; and a spare blade cartridge for storing more than one spare blade. The blade carrier, the locking piece and the spare blade cartridge are arranged in the internal chamber. The blade carrier is arranged to be movable between a first position and a second position, and when the blade carrier is at the first position, the blade carried by the blade carrier extends out of the housing, when the blade carrier is at the second position, the blade carried by the blade carrier retracts into the housing.
Claims
1. A utility knife, comprising a knife head having an internal chamber; a blade carrier for carrying a single blade; a locking piece for locking the single blade on the blade carrier, wherein the locking piece is attached to the blade carrier; a spare blade cartridge for storing more than one spare blade; and wherein the blade carrier, the locking piece and the spare blade cartridge are arranged in the internal chamber, the internal chamber has an opening that allows for the single blade to extend outside the internal chamber and retract back into the internal chamber, the blade carrier is arranged to be movable between a first position and a second position, the blade carrier is adapted to retain the single blade with the single blade protruding from the internal chamber when the blade carrier is in the first position, and the blade carrier is adapted to retain the single blade with the single blade totally confined within the internal chamber when the blade carrier is in the second position; and further comprising a handle; wherein the knife head and the handle are connected via a first axis pin, and the knife head is arranged to be capable of rotating around the first axis pin to be retracted into the handle; wherein an arc slot having a radial recess is arranged on the handle, and the arc slot has a center that aligns with a center of the first axis pin; and a switching piece with a block arranged in the internal chamber of the knife head; such that the switching piece has an end aligned with a side of a tail of the blade carrier when the blade carrier is at the first position, and such that moving of the blade carrier between the first position and the second position will cause the switching piece to be moved between a third position and a fourth position; wherein the switching piece is further arranged such that: the block of the switching piece is engaged with the radial recess of the arc slot preventing the block from rotating when the switching piece is at the third position with the blade carrier at the first position; and the block is moved from the radial recess to the arc slot when the switching piece is moved from the third position to the fourth position, which permits the rotation of the block in the arc slot when the knife head is rotated around the first axis pin and retracted into the handle.
2. The utility knife as defined in claim 1, wherein the spare blade cartridge is arranged to be connected to the knife head via a second axis pin, and a knob is arranged on an edge of the spare blade cartridge which is configured to be capable of rotating the spare blade cartridge around the second axis pin and out of the inner chamber of the knife head to load the spare blade.
3. The utility knife as defined in claim 1, wherein further comprises a biasing spring configured to engage the knife head, and the biasing spring is arranged to abut the switching piece, when the switching piece is moved from the third position to the fourth position under the function of the blade carrier, the biasing spring is compressed to bias the switching piece.
4. The utility knife as defined in claim 1, wherein a magnetic element is arranged on the blade carrier, and the magnetic element is arranged such that when the blade carrier is at the second position and is empty, a nearest one of the spare blades to the blade carrier is transferred from the spare blade cartridge to the blade carrier by magnetic force.
5. The utility knife as defined in claim 4, wherein the magnetic element is of magnetic steel.
6. The utility knife as defined in claim 4, wherein the magnetic element is arranged to be embedded in the blade carrier.
7. The utility knife as defined in claim 4, wherein the locking piece has a lock tongue configured to engage notches on a back of the single blade, and the lock tongue is configured to engage the notches under a magnetic force of the magnetic element.
8. The utility knife as defined in claim 7, wherein the lock tongue engages the notches with a pivotal attachment, and the lock tongue has a chamfer plane on a second side opposite to the first side.
9. The utility knife as defined in claim 7, wherein the lock tongue has one or two chamfer planes on a first side thereof parallel and close to the back of the single blade.
10. The utility knife as defined in claim 9, wherein the spare blade cartridge has a flange with a hook, and the hook of the flange is configured to engage notches on a back of the spare blade.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) FIG. 1 is a front view of a preferred embodiment of the present invention, and the blade is extending out of the knife head.
(2) FIG. 2 is a front view of the utility knife shown in FIG. 1, and the blade is retracted into the knife head.
(3) FIG. 3 is an exploded view of the utility knife shown in FIG. 1.
(4) FIG. 4 is a perspective view of the blade carrier shown in FIG. 3.
(5) FIG. 5 is a perspective view of the thumb button shown in FIG. 3.
(6) FIG. 6 is a perspective view of the second housing shown in FIG. 3.
(7) FIG. 7 is a perspective view of the locking piece shown in FIG. 3.
(8) FIG. 8 is a sectional view of the knife head shown in FIG. 1.
(9) FIG. 9 is a cross-sectional view taken along line A-A of the knife head shown in FIG. 8, at this time, the unlocking button is not pressed down.
(10) FIG. 10 is a front view of the knife head shown in FIG. 1.
(11) FIG. 11 is a cross-sectional view taken along line B-B of the knife head shown in FIG. 10, at this time, the unlocking button is pressed down.
(12) FIG. 12 is a perspective view of the spare blade cartridge shown in FIG. 3.
(13) FIG. 13 shows the spare blade cartridge shown in FIG. 3, which is pivotally rotated out of the knife head to load the spare blade.
(14) FIG. 14 is a perspective view of the spare blade cartridge shown in FIG. 3 in another embodiment.
(15) FIG. 15 is a perspective view of the switching piece shown in FIG. 3.
(16) FIG. 16 is a perspective view of the knife head shown in FIG. 1.
(17) FIG. 17-18 are sectional views of the utility knife shown in FIG. 1.
(18) FIG. 19-20 are sectional views of the utility knife shown in FIG. 2.
(19) FIG. 21 is an sectional view of the utility knife shown in FIG. 1 and FIG. 2, which is retracted into the handle.
(20) FIG. 22 is a front view of the knife head shown in FIG. 2.
(21) FIG. 23 is a cross-sectional view taken along line C-C of the knife head shown in FIG. 22.
(22) FIG. 24 is a front view of the utility knife in another embodiment of the present invention.
(23) FIG. 25 is a cross-sectional view taken along line D-D of the knife head shown in FIG. 24.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
(24) According to a preferred embodiment of the present invention, a foldable utility knife with a spare blade cartridge is shown in FIG. 1, 2. The foldable utility knife shown in FIG. 1 is in a state suitable for the work of cutting and etc., at this time, the knife head 1 has extended from the handle 2, and the thumb button 4 has been pressed down and slided to the first position 100 to force the blade 3 to extend from the knife head 1. At this time, if the blade 3 needs to be replaced for it is dull or any other reasons, the blade 3 can be directly pulled out from the knife head 1 by only pressing the unlocking button 5, then by pressing down the thumb button 4 and returning it to the second position 200 shown in FIG. 2, loading procedure of the blade is completed automatically. Then by pressing down the thumb button 4 again and pushing it forward to the first position 100, a new blade 3 will extend from the knife head 1 for use.
(25) In a preferred embodiment, the knife head 1 and the handle 2 are connected via the first axis pin 6. Similar to a regular foldable knife, the knife head 1 can rotate around the first axis pin 6 and be retracted into the handle 2, as shown in FIG. 21.
(26) FIG. 3 is an exploded view of the knife head 1. As shown in FIG. 3, the housing of knife head 1 is combined by a first housing 11 and a second housing 12, and thus defines an inner chamber 13 in the knife head 1. A spare blade cartridge 14 and a blade carrier 16 is arranged in parallel in the inner chamber 13. In the inner chamber 13, the spare blade cartridge 14 is on the side adjacent to the first housing 11, and blade carrier 16 is on the side adjacent to the second housing 12. The blade carrier 16 is arranged to be able to move forward and backward between the first position 100 and the second position 200 in the inner chamber 13, and when the blade carrier 16 carrying the blade 3 moves to the second position 200, the blade 3 on the blade carrier 16 is aligned and adjoined with more than one spare blade 15 in the spare blade cartridge 14.
(27) As shown in FIG. 3 and FIG. 12, the spare blade cartridge 14 has a blade caging frame on the side 140 facing the blade carrier 16, the blade caging frame comprises flanges 141, 142 extending from the side 140, the spare blades 15 are maintained between the flanges 141, 142.
(28) As shown in FIG. 3 and FIG. 4, the blade carrier 16 has a blade caging frame on the side 160 facing the spare blade cartridge 14, the blade caging frame comprises flanges 161, 162 extending from the side, the blade 3 is retained between the flanges 161 and 162. The blade carrier 16 also has the platform 163 being flush with the blade 3 carried on the blade carrier 16, when the blade 3 moves away from the second position 200 along with the blade carrier 16, the platform 163 replaces the blade 3 and abuts the spare blades 15 to make the spare blades 15 stay in the original position.
(29) The thumb button 4 is arranged on the blade carrier 16. As shown in FIGS. 3, 4 and 5, the thumb button 4 includes a pressing part 41, an inserting part 42 and a spring 43. The slot 164 for receiving the inserting part 42 is arranged on the blade carrier 16. When the inserting part 42 is inserted into the slot 164, the locking block 44 is arranged on the side that is facing the second housing 12. As shown in FIG. 6, the track 121 and a plurality of recesses matching with the locking block 44 are arranged along the moving direction of the thumb button 4 on the second housing 12, the recesses at least includes recesses 122, 123 shown in FIG. 6. When press down the pressing part 41, the spring 43 is compressed, the locking block 44 declines below the recesses 122, 123, at this time, the thumb button 4 can be pushed to move forward and backward in the track 121. When the locking block 44 moves to the place right under the recess 122, release the pressing part 41, the locking block 44 moves upward under the function of the spring 43, and is stuck into the recess 122, the thumb button 4 can no longer move forward or backward, and at this time, the blade carrier 16 is positioned at the second position 200. When the locking block 44 moves to the place right under the recess 123, release the pressing part 41, the locking block 44 moves upward under the function of the spring 43, and is stuck into the recess 123, the thumb button 4 can no longer move forward or backward, and at this time, the blade carrier 16 is positioned at the first position 100.
(30) It should be pointed out that, in the present embodiment, the thumb button 4 is arranged on the side of the blade carrier 16 that is facing the second housing 12 (i.e. the side opposite to the side 160), and only matches with the recess on the second housing 12, the spare blade cartridge 14 or the first housing 11 is not involved, this provides conditions for arranging that the relatively independent spare blade cartridge 14 pivotally rotating the spare blade 15 out from the knife head 1 to load in the further embodiment that would be elaborated later.
(31) As shown in FIG. 3 and FIG. 7, in the prior art two notches 31, 32 are arranged on the back of the blade 3 and the spare blades 15, and the locking piece 7 has lock tongues 71, 72 that match with the notches 31, 32. As shown in FIG. 22 and FIG. 23, when the blade 3 is at the second position 200, the notches 31, 32 match with the locking piece 7 on the blade carrier 16 to lock the blade 3 on the blade carrier 16, this makes the blade 3 be able to move forward and backward between the first position 100 and the second position 200 with the blade carrier 16, and makes the blade 3 stable when it performs cutting or other work at the first position 100. In the U.S. Pat. No. 6,553,674, the locking piece 106 is arranged to translationally move perpendicular to the blade 72 under the function of the external force to make the lock tongue 100, 102 reach into the notches 78, 76 or retreat from the notches 78, 76 to accomplish locking or unlocking the blade 72. The defect of the translational movement is that when performing locking and unlocking, the traveling distance of locking piece is relatively long and the lateral space needed is large, this makes the knife head thicker.
(32) Different from the translational movement in the U.S. Pat. No. 6,553,674, the locking piece 7 in the present embodiment adopts a pivotally rotating way to lock and unlock the blade 3. As shown in FIGS. 3, 4 and 7, the locking piece 7 in the present embodiment comprises a pivot part 73, the pivot part 73 matches into the pivot recess 165 that is arranged on the side 160 of the blade carrier 16, thus the locking piece 7 can pivotally rotate around the pivot recess 165 on the side that is opposite to the side 160. Further, the magnetic element 8 is arranged in the blade carrier 16. In the present embodiment, the magnetic element 8 is a magnetic steel embed in the embedding hole 81 on the blade carrier 16. In the locking status, the locking piece 7 stays in the upright position under the magnetic force of magnetic steel, at this time, the lock tongues 71, 72 pass through the openings 166, 167 and reach into the notches 31, 32, as shown in FIG. 23. Additionally, as shown in FIG. 8, 9, when the blade carrier is at the first position 100, the abutting part 74 of the locking piece 7 is aligned with the unlocking button 5, and both of them are above the back of the blade 3. At this time, press down the unlocking button 5, the unlocking button 5 will push the abutting part 74 of the locking piece 7 to make the locking piece 7 pivotally rotate around the pivot recess 165, and make the lock tongues 71, 72 retreat from the notches 31, 32, at this time the blade 3 is in the unlocking status, as shown in FIGS. 10, 11. When the thumb button 5 is released, the locking piece 7 will automatically return to the upright position under the magnetic force of magnetic steel. Further, to reduce weight or facilitate processing, the body of the locking piece 7 can be made of plastics or light alloy material, at this time, additional parts that can be attracted by the magnetic force of the magnetic element 8 can be arranged on the locking piece 7, such as the thin steel sheet 75.
(33) It should be pointed out that, the effect exerted on the locking piece 7 by the magnetic element 8 can be replaced by the spring element, such as spring or reed, i.e. the locking piece 7 can take advantage of the spring element such as spring or reed to make itself stay or return to the aforementioned upright position. However, the magnetic element 8 can be simply embedded in the blade carrier 16, it is easy to install and occupies no extra space, and thus reduces the thickness of the knife head 1.
(34) It can be understood that, when the blade carrier 16 is at the second position 200, the lock tongues 71, 72 can be preferably arranged to be at most flush with the blade 3, as shown in FIG. 23. As can be seen obviously from FIG. 7, in the present embodiment, chamfering is performed to the two sides of the direction of the back and forth movement of the lock tongue 71, 72 of the locking piece 7, so that the first chamfer planes 76 are formed as shown in the figure. It can be understood that, the chamfering can be performed only to one of the lock tongue 71, 72 or to one side as needed. Moreover, fillets can be performed so that the first chamfer planes 76 formed in this way would be an arc plane.
(35) Besides, in the present invention, chamfering is performed at the bottom of the lock tongues 71, 72, and the second chamfering plane 77 is formed as shown in FIG. 7, in this way, the locking piece 7 can deflect a relatively small angle around the pivot recess 165 to make the lock tongue 71, 72 retreat from the notches 31, 32 of the blade 3, this reduces the traveling distance needed for unlocking the locking piece 7, and further reduced the thickness of the knife head 1.
(36) When unlocking button 5 is pressed down, the blade 3 is in the unlocking status. At this time, if the blade 3 needs to be replaced, the blade 3 can be pulled out directly from the knife head 1, and then press the thumb button 4 to drive the empty blade carrier 16 back to the second position 200. Under the magnetic force of the magnetic steel 8, one or more spare blades 15 in the spare blade cartridge 14 as a whole move translationally to the side 160 of the blade carrier 16, wherein the nearest spare blade 15 to the side 160 is now completely attach to the side 160, at the same time the lock tongues 71, 72 would also reach into the notches 31, 32 of the spare blade 15 to lock it. It means that the spare blade 15 has been transferred to the blade carrier 16, and becoming the new blade 3, the process of loading blade has been accomplished automatically.
(37) It should to be pointed out that, as disclosed in the U.S. Pat. No. 6,553,674, the spare blade 74 can also be transferred to the blade carrier 44 from the spare blade cartridge 84 under the biasing force of the spring element.
(38) For the foldable utility knife, since the knife head is folded into the handle, the knife head had better to be as thin as possible, otherwise the knife as a whole would be too thick, which is inconvenient to operate or to carry. In the present embodiment, the application of the magnetic element 8 does not need the spring element matching with the locking piece 7 and occupying the extra space as well as the spring element for loading the blade, and further reduces the thickness of the knife head 1.
(39) Besides, different from the openable and closable cover arranged on the side of the knife 10 in the U.S. Pat. No. 6,553,674, the spare blade cartridge 14 in the present embodiment is arranged to be able to pivotally rotate out of the knife head 1 to load the spare blade 15.
(40) As shown in FIGS. 3, 12, 13, the spare blade cartridge 14 is pivotally connected to the knife head 1 between the first housing 11 and the second housing 12 via the second axis pin 111 and pin holes 112, 145, 126, and the knob 143 exposed out of the second housing 12 is arranged on the edge of the spare blade cartridge 14 for convenient manual operations. When the knife head 1 is in the expanded status as shown in the FIGS. 1, 2, the spare blade cartridge 14 can pivotally rotate out around the second axis pin 111 by the hand prodding the knob 143, and then the spare blade 15 is loaded into the spare blade cartridge 14, as shown in FIG. 13. Further, in the present embodiment, the positioning flange 144 is arranged on the spare blade cartridge 14, the positioning flange 144 extends from the side 140 of the spare blade cartridge 14 and exceeds the flanges 141, 142, and above the upper face 168 of the blade carrier 16 in the vertical direction. When the blade carrier 16 is at the second position 200, since the positioning flange 144 is abutting the upper face 168 of the blade carrier 16, at this time, the spare blade cartridge 14 could not be pulled out of knife head 1. When the blade carrier 16 is at the first position 100, the positioning flange 144 is not obstructed by the upper face 168 of the blade carrier 16, at this time, the spare blade cartridge 14 can be pulled out of knife head 1.
(41) FIG. 14 shows another preferred embodiment 14 of the spare blade cartridge 14. As shown in FIG. 14, in this embodiment, a part of the flange 141 of the spare blade cartridge 14 is of a cantilever 145 structure, the hook 146 is arranged at the ends of the cantilever 145. In this way, when the spare blade 15 is loaded into the spare blade cartridge 14 as shown in FIG. 13, the hook 146 can be clamped into the notch 31 or notch 32 on the spare blade 15 in a snap-fit way, thus the spare blade 15 is clamped in the spare blade cartridge 14. Besides, since the hook 146 is also a part of the flange 141 of the spare blade caging frame, the hook 146 also has guiding effect when the spare blade 15 moves towards the side 160 of the blade carrier 16 in the blade-loading process.
(42) The above describes in detail the knife head 1 in a preferred embodiment of the present invention. It should be pointed out that, although the present preferred embodiment is a foldable utility knife, all the disclosed technical features of the knife head 1 can still be individually or collectively applied to other foldable or unfoldable utility knives, such as the utility knife disclosed in the U.S. Pat. No. 6,553,674, for the person skilled in the art, this application does not need inventive work. In the present application, the embodiment of the unfoldable utility knife shown in FIGS. 24, 25, applies the aforementioned locking piece 7 and the magnetic element 8.
(43) Further, the preferred embodiment of the present invention as shown in FIG. 1 can also be arranged such that only when the thumb button 4 and the blade carrier 16 are at the second position 200, i.e. when the blade 3 carried by the blade carrier 16 is retracted into the knife head 1, the knife head 1 can then be retracted into the handle 2.
(44) Under this situation, as shown in FIGS. 3, 6, 15 and 16, the switching piece 9 and the biasing spring 93 are arranged in the knife head 1. In the present embodiment, the switching piece 9 is a U-shape body mounted in the holding recess 125 outside of the pipe 124 of the first axis pin 6, the pipe 124 extends from the inner side of the second housing 12. After installation, the two ends 91 of the U-shape body is aligned with the side 169 of the tail of the blade carrier 16, the block 92 that laterally extends from the head of the U-shape body passes through the opening 126 and is partially exposed out of the second housing 12. The biasing spring 93 is arranged to bias the switching piece 9 to make the head of the U-shape body of the switching piece 9 abut the pipe 124, so that the switching piece 9 is capable of moving in the knife head 1 yet incapable of rotating relative to the knife head 1. When the blade carrier 16 is at the first position 100, the block 92 is at the third position 300. When the blade carrier 16 moves to the second position 200, the side 169 of its tail pushes the two ends 91 of the switching piece 9 to make the switching piece compress the biasing spring 93 and switch to the fourth position 400, as shown in FIGS. 17-20.
(45) As shown in FIGS. 17-20, on the handle 2, along the moving track of the block 92 at the fourth position which pivotally rotates with the retracting and extending of the knife head 1, the arc slot 21 matching with the block 92 is arranged and its center is the axis of the first axis pin 6. Besides, the radial recess 22, which is corresponding to the first position 300 of the block 92 when the knife head 1 is in the expanded status, is arranged on the arc slot 21. Therefore, when the knife head 1 is in the expanded status, and the blade carrier 16 is at the first position 100, the block 92 is matching in the radial recess 22, at this time, the knife head 1 cannot be retracted into the handle. When the blade carrier 16 is moved to the second position 200, the switching piece 9 is pushed by the blade carrier 16 to make the block 92 be off the radial recess 22 to switch into the second position 400 in the arc slot 21, at this time, the block 92 can pivotally rotate in the arc slot 21, thus the knife head 1 can be retracted into the handle 2, as shown in FIG. 21.
(46) The foregoing description details the preferred embodiments of the invention. It should be understood that with the general technique of this field, no inventive work is necessary as to make multiple amendments and changes according to conception of this invention. Therefore, all the technical schemes gained from logical analysis, deductions or limited experimentation based on the conception of the present invention by technicians in this field, should be considered within the protection range asserted in the Claims.
