Patent Publication Number: US-9409299-B2

Title: Knife

Description:
FIELD OF THE INVENTION 
     The invention relates to a knife. 
     BACKGROUND OF THE INVENTION 
     A knife is well-known from published prior use. It comprises a housing in which a blade holder is located. The blade holder can be moved between a safety position and a cutting position. The blade is inaccessible in the housing when in the safety position, and projects from the housing when in the cutting position. A spring is fastened to the housing and to the blade holder, and urges the blade holder for example into the safety position. 
     The blade holder is often removed from the housing in order to change blades. As this is done, the spring is frequently overstretched and thus destroyed. 
     OBJECT OF THE INVENTION 
     The object of the invention is to create a knife that allows the blade to be conveniently changed while preventing any damage to the spring. 
     SUMMARY OF THE INVENTION 
     This object is achieved by a knife according to the invention that comprises a housing provided with a blade holder. The blade holder can be moved between at least one safety position in which a blade supported in the blade holder is inaccessible in the housing, and at least one cutting position in which the blade holder is in a position in which the blade projects from the housing. The blade holder is located, for example, inside the housing. It can be for example slidable on guide faces of the housing. 
     A spring is attached to the housing and to a first entrainment formation. The term spring according to the invention can include any form of biasing element, such as for example a metal spring, gas cylinder, etc. This can refer, for example to a tension spring or a compression spring. The spring can be loaded for example by moving the blade holder from the safety position into the cutting position. Alternatively or additionally, the spring can be loaded by moving the actuator or the actuating component from a first position into a second position. The first position is for example a rear position and the second position is for example a front position. 
     Actuator as defined by the invention in the broadest sense refers to a device for moving the blade holder. For example, an actuating handle can be part of the actuator. The actuator can for example comprise a motion-transmitting mechanism between the handle and the blade holder. 
     A second entrainment formation is associated with the blade holder or the actuator. The second entrainment formation is provided on or attached for example to the blade holder or the actuator, i.e. one part or more parts of the actuator. For example, the second entrainment formation is formed directly or indirectly on the blade holder or the actuator. The second entrainment formation can be moved in releasable contact with the first entrainment formation. The second entrainment formation is carried along whenever, for example the blade holder is moved from the safety position to the cutting position by moving the actuator from the unactuated position to the actuated position. The first entrainment formation is driven, for example by the second entrainment formation, and moved from the rear position to the front position, thereby tensioning the spring. The second entrainment formation that is in contact with the first entrainment formation is also loaded by the spring. If, for example the second entrainment formation is attached to the blade holder, the blade holder is forced by the spring, for example into the safety position. If the blade holder is fixed or coupled to the actuator, it is entrained thereby. 
     When a blade is changed, the blade holder can be removed, for example from the housing without the need for the spring to be disconnected, since the entrainment formations can be detached from each other. The blade holder is, for example removed from the housing together with the second entrainment formation, while the first entrainment formation remains in place in the housing with the spring. 
     In one embodiment, the first entrainment formation is associated with a slide that can shift between a rear position and a front position on a guide of the housing. The first entrainment formation is composed, for example of a pin. The pin projects, for example into the housing so as to enable it to come into contact with the second entrainment formation when moved from the rear position to the front position and carry this element along. 
     The guide of the slide comprises, for example a first guide on the housing and a second guide on the slide. The first guide is formed for example by a groove or a slot. The second guide is provided, for example by a guide structure of the slide. 
     The second guide is provided, for example by the first entrainment formation. 
     In one embodiment of the invention, the blade is retained in a blade seat between a first support face of the blade holder and a second support face of a retaining element. The retaining element can be moved, for example between a retaining position and a release position. In the retaining position, the blade is retained by a nonpositive and/or positive clamp between the first supporting face and the second supporting face. When in the release position, the retaining element can be moved away from the blade holder, thereby enabling the blade to be removed from the blade seat. 
     Together with the blade holder, the retaining element creates, for example a pivot joint. The pivot joint can, for example be at a first end region of the blade holder and of the retaining element. The blade can be retained, for example in the blade seat at a second end region of the blade holder and of the retaining element. 
     The retaining element for example forms the actuator. The housing here is formed with a groove through which the retaining element passes. A ridge of the actuator, for example passes through the groove. 
     Unwanted movement of the retaining element from the retaining position to the release position can be prevented by an approach whereby the retaining element includes at least one arm that grips under the adjacent side wall of the housing. The retaining element is retained on the blade holder, for example by a pivot joint and additionally by the arm, the arm precluding any unwanted movement by the retaining element between the retaining position and the release position. The retaining element can then be moved into the release position, whenever the assembly unit consisting of the blade holder and actuator is removed from the housing. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
       Additional advantages are described in the following with reference to an embodiment shown in the figures. Therein: 
         FIG. 1  is an exploded view of the knife comprising a housing, a spring slide, a blade holder, and an actuator. 
         FIG. 2  is a detail from the exploded view of the knife with the spring slide installed on the housing. 
         FIG. 3  is a top view of the knife with the blade holder and the actuator not installed. 
         FIG. 4  is a section along line IV-IV in  FIG. 3 . 
         FIG. 5  is a top view of the knife with the blade holder and the actuator installed and the blade in the safety position. 
         FIG. 6  is a section along line VI-VI in  FIG. 5 . 
         FIG. 7  is a top view of the knife as in  FIG. 5  with the blade in the cutting position. 
         FIG. 8  is a section along line VIII-VIII in  FIG. 7 . 
         FIG. 9  is a schematic top view of the blade holder and actuator. 
         FIG. 10  is a section along line X-X in  FIG. 9 . 
     
    
    
     SPECIFIC DESCRIPTION OF THE INVENTION 
     The knife as a whole is identified at  10  in the figures. Identical reference numerals in the various figures identify corresponding parts, including where lower-case letters have been added or omitted. 
       FIG. 1  shows that the knife  10  comprises a housing  11 , a spring slide  12 , a blade holder  13 , and also an actuator  14 . 
     The housing  11  in this embodiment is made of sheet metal. Side flaps  15  and  16  are provided on the housing  11  that are folded over such that edges  17  and  15  of these flaps point toward each other and create guide surfaces. A groove  19  is formed between the edges  17  and  18 . A floor surface  20  is formed by a floor wall  21  of the housing  11 . The floor wall  21  is located opposite a top wall  22  formed by the side flaps  15  and  16 . A blade  47  not shown in  FIG. 1  is located between the floor surface  20  and the side flaps  15  and  16 . A slot  23  is formed in the floor wall  21 . A tongue  34  ( FIGS. 7 and 8 ) is cut out of a rear end  28  of the housing  11  and is folded over. The tongue  34  is not shown in  FIG. 1 . 
     The spring slide  12  has a slide face  24 . In addition, the spring slide  12  is formed with an entrainment pin  25  as well as a spring hook  26 . The spring slide  12  is formed with a recess  27  on a side opposite the slide face  24 . 
     The blade holder  13  has a face formed as a blade seat  29 . The blade  47 , which is not shown in  FIG. 1 , is retained between the blade holder  13  and the actuator  14 . The actuator  14  is provided with ridges  30  that prevent the fingers of a user from sliding off. 
       FIG. 2  illustrates the spring slide  12  in the installed position. The slide face  24  rests against an outer face  31  of the floor wall  21 . The entrainment pin  25  passes through the slot  23 . This limits movement of the spring slide  12 . In the rear position of  FIG. 2 , the entrainment pin  25  is at a rear end  32  of the slot  23 . When in the front position, the entrainment pin  25  is at a front end  33  of the slot  23 . 
       FIG. 3  shows the tongue  34  at the rear end  28  of the housing  11 . One end of a spring  35  is fastened to the tongue  34 . Another end is retained on the spring hook  26  of the spring slide  12 . 
     A front end  39  of the housing  11  includes a guide surface  36  that is joined to the floor by an angled wall region  38 . The guide surface  36  is at a spacing from lower faces  37  of the side flaps  15  and  16  that is less than their spacing from the floor surface  20 . The blade holder  13  and the blade  47  (not shown in  FIG. 4 ) can thus be slid between the faces  37  and the floor surface  20  when shifting between the safety position ( FIGS. 5 and 6 ) and the cutting position ( FIGS. 6 and 7 ). 
       FIG. 4  shows that a pivot pin  40  is provided on the blade holder  13  that locks into a bearing seat  43  of the actuator  14 . As a result, the blade holder  13  forms a pivot G with a pivot point a. Hook-shaped arms  41  including retaining faces  42  are provided on the actuator  14 . When the blade holder  13  and the actuator  14  are installed, the arms  41  grip under the side flaps  15  and  16  so as to prevent the actuator from being pivoted in a direction z out of a retaining position into a release position. 
     The blade seat  29  comprises a stud  44  that passes through and fits with a correspondingly shaped hole in the blade  47  and thus retains the blade  47  in a positive-locking manner in the blade seat  29 . In addition, the blade seat  29  is formed with a recess in which a magnet  45  is installed to make the blade  47  cling to the blade seat  29 . The bottom of the blade holder  13  forms an entrainment face  46 . 
     The blade holder in  FIG. 5  is in the safety position. The blade  47  shown only in outline in  FIG. 5  is supported in the housing  11  in such a way that the cutting edge of the blade  47  is inaccessible to the user as a result of being covered by the side flaps  15  and/or  16 . When the assembly comprised of the actuator  14 , the blade holder  13 , and the blade  47  is moved in direction x 1 , the entrainment face  46  of the blade holder  13  engages the entrainment pin  25  and thereby moves the spring slide  12  in the direction x 1 . This action tensions the spring  35 . Movement of the actuator  14  in the direction x 1  is possible only up until the entrainment pin  25  strikes the front end  33  of the slot  23 . The blade holder  13  is then located in the front cutting position in which the blade  47  projects by the maximum amount from a front opening  48  of the housing  11  as shown in  FIGS. 7 and 8 . 
     When the user releases the actuator  14 , the spring slide  12  is pulled in the direction x 2  by the spring  35 , while at the same time the blade holder  13  and the actuator  14  are also moved in the direction x 2  by the entrainment pin  25  and the entrainment face  46 . 
     The housing  11  comprises a cap, not shown, that can close or reveal a rear opening  49  of the housing  11 . In order to change the blade, the cap is opened, and the assembly unit comprising the blade holder  13 , the actuator  14 , and blade  47  are pulled back out of the rear opening  49  of the housing  11 . 
     At the point where supporting arms  41  are no longer engaged under the side flaps  15  and  16 , the actuator  14  can be pivoted about the pivot point a away from the blade holder  13  in pivot direction z 1  into the release position, thereby allowing the blade  47  to be removed from the blade seat  29  and a new blade  47  to be inserted into the blade seat  29 . The actuator  14  is then pivoted back into the retaining position, and the assembly unit consisting of the blade  47 , the blade holder  13 , and the actuator  14  is pushed back into the housing  11 . The unillustrated closure is then closed. The knife is then once again functionally ready for cutting.