Perforator

Technical field

The invention is related to the office equipment, particularly to the office equipment intended for perforation of different types of materials, mainly of paper.

Background Art

Currently, various types of perforators exist in the area of the office equipment that are based on the lever principle.

The perforator covered by the patent DE 2017749 Al has been designed in such a way that it has asymmetrically seated and pivoted levers in the plane of the punches transmitting compressive force to these punches. The main disadvantage of this solution is based on the fact that the area of lever movement is open and hazard of injury is threatened, for example the jamming of fingers. The rather small surface for application of pressure by the hand of the operator, uneven distribution of forces on the punches and the fact that the design requires the highest compressive force in time of shearing the material are the main disadvantages of this solution. Imperfect or partial perforation of the material occurs as a result of these design disadvantages.

The perforator covered by the patent DE 6M9011500.7 has been designed in such a way that the levers are pivoted in the plane of punches. The point of application of compressive force is located in the middle of the perforator that should ensure uniform distribution of compressive force on both punches. Disadvantages include, like in the previous design, small surface for action of the pressure force, the levers accessible during their action resulting in hazard of injury and the fact that the heaviest force must be applied during shearing. Another disadvantage is the fact that the levers have short length therefore it is necessary to apply a heavy force for perforation of the material.

Another structural solution of the perforator covered by the patent DE 10051 625 is based on seating the levers in the punches plane, while the levers have the equal lengths and

application of forces is based on the principle of eccentric action. The disadvantage of this design is based on the fact that the compressive force does not act directly in the middle of the perforator, movement of levers and punches is not uniform resulting in uneven shearing of the material requiring the change in the compressive force action.

The mechanism of the back stop for guarantee of symmetric perforation is designed, as a rule, as a shifting element that must be shifted out of the perforator before perforation itself. This back stop prevents insertion of paper into the perforator. Operation of the back stop is usually non-conformed and prolongs the total time that is necessary for perforation of the paper.

Summary of the Invention

The aforementioned deficiencies are partially remedied by the structural design of the perforator according to this invention consisting of the frame, actuator, lever I, lever II, two punches, two dies and a cover; its essence is based on the fact that the actuator of the perforator is equipped with a boss, on which the contoured surface I and contoured surface II have been formed, while the lever I surface has been formed against the contoured surface I on the lever I and the lever II surface has been formed against the contoured surface II on the lever II.

Further the gist of the solution is based on the fact that the cover of the perforator is equipped with an inner surface and the actuator with a circumferential surface, while the inner surface of the cover represents the negative of the actuator circumferential surface.

The gist of the solution is also based on the fact that the perforator has a groove in its magazine with at least one boss reaching to the groove. The back stop is swivel and push fit in the groove with its tie-rod. At least one surface has been formed on the back stop tie-rod. This surface forms together with the boss the link mechanism determining the displacement of the back stop depending on the length of the back stop protrusion.

The perforator assembled in the above way, consisting of the frame, actuator, two punches, two dies, lever I, lever II and cover, where the inner surface of the cover forms a guide for the circumferential surface of the actuator allows retraction of the actuator into its

cover after its pushing. The actuator is also equipped with a boss with the contoured surface I and the contoured surface II. These contoured surfaces are in contact with the surfaces of the levers I and II. The levers are pivotally attached in the frame using pivots. The punches are attached in grooves of the levers, which are also movable anchored to the levers using recesses. Packing pieces are also placed in the grooves that prevent rubbing the levers at the contact point with the punches.

The spring I located between the lever I and the lever II pushes away lower ends of the levers from each other and causes their rotation. Due to this rotation, the punches are pushed to the upper basic position and at the same time the spring II lifts the actuator to its upper position.

When pressing the actuator, the boss is gradually pushed between the lever I and the lever II causing that the contoured surface I of the boss 61 acts on the lever I surface and the contoured surface II acts on the surface II of lever II resulting in deflection of the both levers. Their movement is transmitted to the punches, and they are moved towards the sheared material. The contoured surfaces I and II has been contour designed in such a way that the resulting movement of the both levers, and also the punches, is uneven in the course of pressing. The declination of contoured surfaces is adapted in the first part of lifting in such a way that it allows fast movement of the punches towards the sheared material. In the second part of lifting, when the punches penetrate through the sheared material, the declination of contoured surfaces is adapted in such a way that the movement of punches is slower and smaller force is necessary for perforation.

The back stop that is seated in the groove of the magazine is shifted after release by the length Ll, then after release to the length L2; the boss in the groove will start to act against the surface that is formed on the back stop tie-rod. In this way the back stop is turned through an angle alpha. During further release, the angle of rotation is not changed, and the back stop can be shifted to the required distance taking into account the size of the material perforated. The back stop surface formed on the stop block can be used for positioning of the perforated material to the correct position.

The gist of solution covered by this invention allows easier and more effective perforation than in the existing perforators, because in case of these perforators, transmission

of movement from the actuator to the punches in the course of pressing was uniform. Nonuniform movement allows to apply smaller force for shearing.

Seating the levers in the perforator according to this invention prevents undesired injury during perforation.

Summary of Figures on Drawings

Fig. 1 represents the perforator in the basic (uncompressed) state.

Fig. 2 represents the perforator in the compressed state.

Fig. 3 represents the perforator in the disassembled state.

Fig. 4 represents the partially released back stop.

Fig. 5 represents the perforator with released and turned back stop.

Best Mode of Carrying out the Invention

The given example of implementation is demonstrative only and does not exhaust the other possible implementations.

Two dies 30 and two punches 20 are seated in the frame ljλ Further, the lever I 40 and the lever II 50 are seated in such a way that the punches 20 are locked in their position using recesses 21 in the groove 141 of the lever 140 and in the groove II 51 of the lever II 50. Packing pieces 73 are inserted in the groove 141. and in the groove II 5JL The spring I 70 is inserted between the lever 140 and the lever II 50 and the both levers are secured in the frame 10 by two pins 72.

Then the cover 80 is pushed on the assembly and locked by additional pushing in such a way that the ribs 1.81. of the cover 80 will snap in the blocking bosses I JJ, of the frame 10. The spring II 71 is inserted between the lever 140 and the lever II 50_and then the actuator 60 is put on in such a way that the circumferential surface 65_ of the actuator 60 is inserted into the inner surface 83. of the cover 80. After pushing the actuator 6O ₁ its blocking bosses II 64 will snap behind the ribs II 82 of the cover 80.

The back stop 100 is seated in the groove 91. of the magazine 90. Then the magazine 90 is mounted on the lower part of the frame 10.

Industrial Applicability

The invention can be used mainly in the area of the office equipment.