Automatic stamper

Abstract: There is described an automatic stamper for imprinting desired letters or characters on documents (2), which includes a printing block (7) having a plurality of stamp units (16) mounted around the circumference of a drum (17), a support frame (6) rotatably and detachably supporting the printing block, and a base structure (1) having a document support surface (4) and supporting thereon the support frame for reciprocal movement toward and away from the document support surface. The stamp units are detachably mounted on stamp support surfaces (18) on and around the circumference of the drum such that the longitudinal axes of the respective stamp units are disposed parallel with the axis of the drum, thereby permitting a compact construction, while the support frame is automatically driven from motor 45 which is adapted to be closed upon setting a document on the document support surface.

Description: This invention relates to an automatic stamping device which is capable of automatically imprinting desired letters or characters on documents. Heretofore, manually-operated stampers have been used. Illustrated schematically in Fig. 7 is a conventional stamping device which is provided with a printing block 70 carrying a stamp unit 73 on each of the three stamp support surfaces 72 formed on the respective peripheral side surfaces of a triangular stamp holder 71 of the printing block. Each stamp unit 73 has a rectangular printed face and is mounted on the stamp support surface 72 such that its longitudinal axis lies in a direction perpendicular to the axis 75 of the stamp holder 71. In order to imprint a letter or letters on a document 74, the printing block 70 is turned about its axis 75 until a desired stamp unit 73 comes to a printing position on the lower side and then the printing block 70 is pressed downward by hand. Such a conventional stamping device, in which the rectangular stamp units are mounted on the holder with their longitudinal axes disposed in the circumferential direction of the holder, however, involves a problem that each one of the stamp support surfaces of the holder is required to have, in the circumferential direction thereof, a length at least equal to the length of the stamp unit to be mounted thereon. Consequently it is often necessary for the printing block to be of an extremely large outside diameter. For example, in the case of a printing block 80 of this kind which, as shown in Fig. 8, has six stamp units 83 mounted on six stamp support surfaces 82 of a hexagonal holder 81, to permit a greater scope in printing, the distance d from the center of the holder 81 to each apex thereof needs to be at least equal to the length l of each stamp unit 83, and consequently the rotational diameter of the printing block as a whole, including the stamp units 83, has to be more than twice the length 1 of the stamp units 83. In addition, in such conventional stamping devices, the printing block has to be pressed down by hand when it is required to imprint a stamp on a document. Such a printing operation is troublesome, and also it is difficult to apply manually a constant printing pressure on the printing block for the purpose of obtaining clean and clear impressions. US-A-4,181,560 discloses an electro-mechanical marking device which is adapted to receive and operate a plurality of interchangeable marking heads. The marking heads are driven in a reciprocating fashion by a solenoid device. In a specifically described embodiment, the marking head comprises a rotatable imprinter wheel of polygonal cross section and having a number of different printing faces. The wheel also comprises a ratchet gear which is engaged by a spring mounted pawl assembly to provide an automatic indexing mechanism. In operation, with each downward stroke of the armative carrying the imprinter wheel to make an imprint, the wheel is caused to rotate by an amount appropriate to bring the next adjacent printing face into position to make the next subsequent impression. The present invention seeks to provide an automatic stamper which is adapted to imprint stamps on documents by means of a printing block having a plurality of stamp units mounted around the circumference of a drum, the stamper employing a printer block which can be compact in size and which is capable of automatically imprinting a selected stamp upon setting a document in a predetermined position, and in which the individual stamp units are readily interchangeable. The automatic stamper in accordance with the present invention comprises an automatic stamper comprising: a printing block (7) having a plurality of stamp units (16) mounted around the circumference of a drum (17), the stamp units (16) being mounted on stamp support surfaces (18) with their longitudinal axes disposed parallel with the axis of said drum; a support frame (6) detachably and rotatably mounting said drum (17); and a motor (45) for driving said support frame (6); and characterised in that each of said stamp units (16) is detachably mounted on a stamp support surface (18) on said drum (17) through a coupling mechanism comprising a hook (35,39) and a coupling hole (36a,38a) provided one on said stamp unit (16) and the other on said stamp support surface (18), respectively, said hook (35, 39) and coupling hole (36a,38a) being disengageably couplable with each other by displacing said stamp unit (16) in the axial direction of said drum (17) over a distance corresponding to the length of engagement of said hook; the stamper further comprising: a base member (1) having a document support surface (4) for setting thereon a document (2) to be imprinted with a stamp and supporting said support frame (6) for vertical movement toward and away from said document support surface (4); and a switch (53) adapted to be closed upon setting a document (2) on said document support surface (4) of said base member (1) to actuate said motor (45) for one reciprocal movement of said support frame (6) toward and away from said document (2). By mounting the stamp units on the drum with their longitudinal axes disposed parallel with the axis of the drum, each of the stamp support surfaces on the circumference of the drum can have a reduced length, corresponding with the width of the stamp unit, so that the outside diameter of the printing block can be reduced to a considerable degree as compared with a printing block which has the longitudinal axes of the stamp units disposed in a direction perpendicular to the axis of the holder. A further advantage of the present stamper is that it provides for a stamp to be imprinted automatically upon setting a document on the document mount surface. Advantageously, the stamp unit and the stamp support surface each have a hook for engagement with a hole on the other member. The printing block may be provided with disc-like handles at the opposite end of the printing block drum for rotating the drum to select the desired stamp unit for printing. Conveniently, each handle bears on its surface index numbers or index marks corresponding to the respective stamp units on the printing block, so that the user can select a desired stamp unit by way of the index number or mark. Further, it is desirable to provide a detention mechanism between the support frame and the printing drum to rotate the latter intermittently or stepwise each time through a predetermined angle. In the case where the printing drum is detachably and rotatably mounted on the support frame by support shafts at opposite ends of the drum received in bearing holes formed in the support frame, such a detention mechanism may conveniently be constituted by a combination of a resilient stopper member protruding into the bearing holes at each side of the support frame and radial projections provided at uniform intervals around the circumference of each support shaft of the printing block in positions corresponding to the respective stamp units. The motor and support frame preferably are coupled through a cam mechanism which is constituted by a cam member mounted on the output shaft of the motor and a cam receiver which is mounted on the support frame to convert the rotational movement of the cam member into a linear reciprocal movement of the frame. Preferably, the cam receiver and support frame are arranged to be displaceable relative to each other in the printing direction, with a resilient means interposed therebetween for adjustment of the printing stroke of the support frame. The invention will now be further described with reference to the accompanying drawings, in which: Fig. 1 is a perspective view of an automatic stamper according to a preferred embodiment of the present invention; Fig. 2 is a partly vertically sectioned view of the stamper; Fig. 3 is a partly horizontally sectioned view of the stamper with a cover removed therefrom; Fig. 4 is an exploded perspective view of major components of the stamper; Fig. 5 is an exploded perspective view of the printing block; Fig. 6 is a sectional view of the printing block; and Figs. 7 and 8 are schematic illustrations of conventional, manually-operated stampers. Referring to Figs. 1 through 4, the reference numeral 1 denotes a base structure of the stamper, which is provided with a rectangular base member 3 with a document mount surface 4 for supporting thereon a document 2 to be printed with a stamp, and a fixed frame 5 located rearward of the document mount surface 4 of the base member 3. A support frame 6 which supports a printing block 7 thereon is vertically movably mounted on the front wall of the fixed frame 5. The support frame 6 is provided with a pair of sliding walls 10a which are extended rearwardly from bearing arms 10 at the opposite sides of the frame 6. The sliding walls 10a are positioned to embrace a guide portion 5a at the front end of the fixed frame 5, and are supported slidably for upward and downward movements along the guide portion 5a by means of interlocking members 13 of generally arch-like shape in section which are fixed on the opposite lateral sides of the fixed frame 5 in engagement with locking flanges 11 on the outer side of the sliding walls 10a and locking flanges 12 on the lateral sides of the fixed frame 5. Accordingly, upon extracting the interlocking members 13 upward, the support frame 6 can be detached from the fixed frame 5. The base structure 1 and support frame 6 may be formed of a synthetic resin material. As seen in Figs. 5 and 6, a plural number of rectangular stamp units, each having desired letters or characters engraved on the printing face, are detachably mounted on stamp support surfaces 18 formed around the outer periphery of a sectionally polygonal drum 17 of the printing block in such a manner that the longitudinal axes of the stamp units are disposed parallel with the axis of the drum 7. Consequently, the printing block can be reduced in outer diameter to a marked degree as compared with conventional printing blocks in which the stamp units are mounted with their longitudinal axes disposed in a direction perpendicular to the axis of the holder. As described hereinafter, the printing block 7 is detachably mounted on the support frame 6 and rotatable stepwise through a predetermined angle. More particularly, and as best seen in Figs. 2 and 3, the bearing arms 10 at the opposite sides of the support frame 6 are each provided with a bearing hole 20, an elastically deformable resilient stopper member 21 having its fore end portion 21a extended into part of the corresponding bearing hole 20, and a notch 22 for detachably mounting the support shaft 19 of the printing block 7 on the fore end portion of the bearing arm 10. Blade-like radial projections 23 are provided at uniform intervals around the circumference of the support shaft 19 in positions corresponding to the respective stamp units 16 (Figs. 5 and 6). These resilient stopper members 21 and blade-like radial projections 23 constitute a detention mechanism which restricts free rotation of the printing block 7. Specifically, unwanted rotation of the printing block 7 is blocked by the fore ends 21a of the resilient stopper members 21 which engage between the adjacent blade-like projections 23 on the support shafts. On the other hand, when the printing block 7 is rotated intentionally, the resilient stopper members 21 are elastically deformed to ride over the projections 23 successively one after another, permitting the printing block 7 to rotate intermittently or stepwise, each time through a predetermined angle. Index marks, for example, index number 26 corresponding to the respective stamp units 16 are provided on the surface of at least one of the disc-like handles 25 which are attached to the outer ends of the support shaft 19, so that the user can select a desired stamp unit 16 by way of the corresponding index number 26. Thus, a desired stamp unit 16 can be selectively put into the printing, i.e. lowermost, position simply by turning a handle or handles 25 until the corresponding index number comes to a predetermined position. When it is required to replace a stamp unit or units 16, the printing block 7 can be easily detached from the support frame 6 through the notches 22. Desirably, the support frame 6 and printing block 7 are formed in a symmetrical shape, so that the printing block 7 can be mounted in an axially reversed position on the support frame 6. Such reversal of the mounting position of the printing block 7 makes it possible to make impressions in an appropriate direction on both upper and lower portions of documents. The blade-like projections 23 may be provided either on the drum 17 or on the support shaft 19, whichever is desirable. As shown particularly in Figs. 5 and 6, the impression members 16 are each constituted by a case 30 of a metallic or synthetic resin material accommodating therein an impression member 31 of a porous material and an ink holding member 32 which is impregnated with ink to supply a necessary amount of ink automatically to the impression member 31. In case of ink exhaustion, ink is re-charged into the ink holding member 32 through an ink replenishing hole 33. Each stamp unit 16 is mounted on the stamp support surface 18 in the manner which will now be described. At one longitudinal end, each stamp support surface 18 on the circumference of the drum 17 is integrally formed with a short hook member 35 having at the upper end thereof a hook portion 35a of short coupling length extending parallel with the stamp support surface 18. At the other hand, the stamp support surface 18 is integrally formed with a socket member 36 having a coupling recess 36a. Correspondingly, formed integrally at one axial end of the rear coupling side of each stamp unit 16 is a socket member 38 with a recess 38a which is engageable with the hook portions 35a of the hook members 35. At the other end of the coupling rear side, the stamp unit 16 is integrally formed with a hook member 39a of short length of engagement, which is engageable with the recesses 36a on the stamp support surfaces 18. As best shown in Fig. 6, each stamp unit 16 can be detachably mounted on a stamp support surface 18 upon engaging the hooks 25 and 39 with the recesses 36 and 38, respectively, by relatively displacing the stamp unit 16 in the axial direction of the drum 17 by an extremely short distance corresponding to the length of the hook portions 35a and 39a. The hook member 35 which is formed on each stamp support surface 18 is centrally provided with a coupling wall portion 35b rising perpendicularly from the stamp support surface 18 for engagement with a notched portion 38c which is formed centrally in an upper wall 38b of the socket member 38 on the stamp unit 16. By engagement of the coupling wall portion 35b with the notched portion 38c, the stamp unit 16 is held in position stably, without sideward movements. Thus, the stamp unit 16 can be attached to or detached from the drum 17 in an extremely facilitated manner, namely, simply by sliding the stamp unit 16 along the stamp support surface 18 by a very short distance corresponding to the coupling length of the hooks 35 and 39. As best seen in Figs. 3 and 4, the support frame 6 is driven from an electric motor 45 which is mounted within the fixed frame 5 and which is connected through a reducing mechanism, not shown, to an output shaft 46 which is extended through the front wall of the fixed frame 5 and coupled with the support frame 6 through a cam mechanism. The cam mechanism includes an eccentric cam disc 48 which is fixedly mounted on the output shaft 46, and a cam receiver 49 which is attached to the support frame 6 to convert an eccentric rotational movement of the cam disc 48 into a reciprocal vertical movement. The cam receiver 49 is in the form of a shallow cup with lower and upper peripheral wall portions 49a and 49b to be abutted against the cam 48, and located in an indented portion of the support frame displaceably relative to the latter in the printing direction. A compression spring 50 is interposed between a stepped portion on each side of the cam receiver 49 and a bottom wall portion 6a of the support frame. As the cam 48 is driven to make one revolution within the cam receiver 49, the support frame 6 is moved vertically to make one reciprocal movement toward and away from the base thereby to imprint letters or characters with a stamp unit 16. Thus, during the first half revolution, the cam 48 is abutted against the lower peripheral wall portion 49a of the cam receiver 49 to push down the latter, and therefore the support frame 6 is pushed down by the spring 50 to imprint a stamp on a document 2 received on the document mount surface 4 (see Fig. 2). In the succeeding second half revolution, the cam 48 is abutted against the upper peripheral wall portion 49b of the cam receiver 49 to push up the latter which has already been urged into abutting engagement with the upper wall portion 6b of the support frame 6 by the biasing force of the spring 50, lifting up the support frame 6 with the cam receiver 6. At this time, the spring 50 which resiliently couples the cam receiver 49 with the support frame 6 serves the function of adjusting the printing stroke of the support frame 6 in such a manner as to imprint a stamp securely on documents of various thicknesses. Upwardly projected from the document support surface 4 is a lever 53 of a switch (not shown) which opens and closes the drive circuit of the motor 45 by backwards and forwards movements in the arrowed directions shown in Fig. 4. Thus, as a document 2 is inserted from the front side of the stamper 1 for setting on the document support surface 4, the lever 53 is pushed back by the fore end of the document 2 to close the switch, whereupon the cam 48 is driven from the motor 45 to make one revolution during which the support frame 6 is moved to make one vertical reciprocal movement as described hereinbefore for imprinting a stamp on the document. In this instance, the cam 48 makes only one revolution even if the switch is continually held in the closed state since the motor 45 would not be actuated unless the switch is re-closed following withdrawal of the document 2. The operating stroke of the switch lever 53, namely, the switch closing position of the lever 53 can be adjusted by way of an adjusting member 54 which is provided at one side of the base 3 to permit adjustment of the printing position relative to the size of documents 2. As shown in Figs. 1 and 2, the fixed frame 5, support frame 6 and printing block 7 are housed in a cover 57 which provides a slit 56 over the document support surface 4 for inserting of documents to be stamped. The handles 25 of the printing block 7 are exposed at the opposite lateral sides of the cover 57. The front surface 58 of the cover 57 bears a display indicating the contents of the stamp units 16 on the printing block 7 by reference to the index numbers on the handle 25. Accordingly, the user can make a desired imprint by selecting a corresponding index number according to the display 58. To use the automatic stamper of the illustrated embodiment of the invention, first of all a desired stamp unit 16 is set in the printing position by turning the handle 25. Then a document 2 to be imprinted with the stamp is inserted onto the document support surface 4 through the slit 56. When the fore end of the document 2 pushes back the switch lever 53 to close the switch, the motor 45 is actuated for one revolution of the cam 48, pushing down the cam receiver 49. As a result the support frame 6 is moved vertically for a reciprocal movement toward and away from the base 3, making an impression on the document 2 with the selected stamp unit 16 in the printing position.

Claims: An automatic stamper comprising: a printing block (7) having a plurality of stamp units (16) mounted around the circumference of a drum (17), the stamp units (16) being mounted on stamp support surfaces (18) with their longitudinal axes disposed parallel with the axis of said drum; a support frame (6) detachably and rotatably mounting said drum (17); and a motor (45) for driving said support frame (6); and characterised in that each of said stamp units (16) is detachably mounted on a stamp support surface (18) on said drum (17) through a coupling mechanism comprising a hook (35,39) and a coupling hole (36a,38a) provided one on said stamp unit (16) and the other on said stamp support surface (18), respectively, said hook (35, 39) and coupling hole (36a,38a) being disengageably couplable with each other by displacing said stamp unit (16) in the axial direction of said drum (17) over a distance corresponding to the length of engagement of said hook; the stamper further comprising: a base member (1) having a document support surface (4) for setting thereon a document (2) to be imprinted with a stamp and supporting said support frame (6) for vertical movement toward and away from said document support surface (4); and a switch (53) adapted to be closed upon setting a document (2) on said document support surface (4) of said base member (1) to actuate said motor (45) for one reciprocal movement of said support frame (6) toward and away from said document (2). An automatic stamper as defined in Claim 1, wherein said stamp unit (16) is provided with a hook (39) disengageably coupable with a hole (36a) provided by said support surface (18), and wherein said support surface (18) is provided with a hook (35) disengageably coupable with a hole (38a) provided by said stamp unit (16). An automatic stamper as defined in Claim 1 or Claim 2, wherein said stamp unit (16) comprises a case (30) having an ink replenishing hole (33) and accommodating therein an impression member (31) of a porous material and an ink-impregnatable member (32) communicating with said ink replenishing hole (33) for supplying ink automatically to said impression member (31). An automatic stamper as defined in any preceding claim, wherein said printing block (7) is provided with at least one operating handle (25) which carries indicia (26) identifying the respective stamp units mounted on said printing block, to permit selection of a desired stamp unit by way of a corresponding index mark. An automatic stamper as defined in Claim 4, further comprising a cover member (57) fitted on said base member (1) to encase therein said support frame (6) and printing block (7) and defining with said document support surface (4) a slit (56) for insertion of a document (2), said cover member (57) providing means for identifying said stamp units (16) correlated with said indicia (26) on said handle (25). An automatic stamper as defined in any preceding claim, further comprising a detention mechanism provided between said support frame (6) and said printing block (7) for rotating said printing block (7) intermittently through a predetermined angle upon closing of said switch (53). An automatic stamper as defined in Class 6, wherein said drum (17) is detachably and rotatably mounted in said support frame (6) by support shafts (19) at opposite ends of the drum received in bearing holes (20) of said support frame (6), and wherein said detention mechanism comprises a resilient stopper member (21) having end portions thereof projecting into said bearing holes (20), and radial projections 23 provided at uniform intervals around the circumference of said support shafts (19) for resilient engagement with said ends of said stopper member. An automatic stamper as defined in any preceding claim, wherein said printing block (7) is adapted to be mounted on said support frame (6) in axially reversed positions. An automatic stamper as defined in any preceding claim, wherein said motor (45) is coupled with said support frame (6) through a cam mechanism (48,49). An automatic stamper is defined in Claim 9, wherein said cam mechanism comprises a cam member (48) fixedly mounted on an output shaft (46) of said motor (45), and a cam receiver (49) mounted on said support frame (6) in engagement with said cam member (48) for converting the rotational movement of said cam member (48) into a vertical reciprocal movement of said support frame (6) toward and away from said base member (1). An automatic stamper as defined in Claim 10, wherein said cam receiver (49) and said support frame (6) are relatively displaceable in the printing direction, and a resilient means (50) is interposed between said cam receiver (49) and said support frame (6) for adjusting the printing stroke of said support frame. An automatic stamper as defined in any preceding claim, wherein said switch (53) is provided with a switch lever (53) protruding into and above the document support surface (4) of said base member (1), and adapted to be pushed back by insertion of a document (2) to be set on said document support surface (4) thereby to close said switch. An automatic stamper as defined in Claim 12, wherein the operating stroke of said switch lever (53) is adjustable.

Inventors: HOSHINO HIROYASU, HOSHINO, HIROYASU
Applicants: ELM INDUSTRY CO LTD, ELM INDUSTRY CO., LTD.
Application year: 1990
Main classification: B41K3
IPC codes: B41K3