Title:
REGISTRATION ALIGNMENT DEVICE FOR EMBOSSING MACHINE
United States Patent 3625330


Abstract:
A registration device of the rack-and-pawl type designed to accurately position the rack in the event said rack is misaligned with the pawl member. A circular rack carries a device that must be accurately positioned but because of the speed at which it rotates a detent mechanism is objectionable. The pawl assembly consists of a sensing pawl pivotally mounted to an engaging pawl and arranged slightly out of alignment and in advance of the engaging pawl. If the rack is stopped in a position where a tooth on the rack is in line with the tooth of the engaging pawl the sensing pawl will rotate the rack slightly to prevent tooth-on-tooth damage.



Inventors:
MARINOFF GEORGE
Application Number:
04/818005
Publication Date:
12/07/1971
Filing Date:
04/21/1969
Assignee:
ADDRESSOGRAPH-MULTIGRAPH CORP.
Primary Class:
Other Classes:
74/527, 400/329
International Classes:
B41B7/04; B41J3/38; (IPC1-7): B41J1/30
Field of Search:
197/6
View Patent Images:
US Patent References:
3236352Keyboard operated automatic marking machine1966-02-22Schacht
3226999Indexing-detent mechanism1966-01-04Allison
3167972Detent mechanism1965-02-02Durgin
3059498Non-dead-centering mechanism1962-10-23Boyd
2972401Variable spacing mechanism for typewriters1961-02-21Salto
2951571Embossing machines1960-09-06Colyer et al.
2941645Varied-feed escapement and adjunct mechanisms1960-06-21Toggenburger
2862595Proportional letter-feed mechanism for typewriters or the like1958-12-02Toggenburger
2627945Indexing mechanism1953-02-10Hooker
2489626Rotary electric switch1949-11-29Doucette
1453867Check writer1923-05-01Fanslow
1271231N/A1918-07-02Schroder



Primary Examiner:
Burr, Edgar S.
Claims:
I claim

1. In a character-forming device, a mechanism for selectively positioning and holding a pair of members which are relatively movable along a position path of travel in any one of a plurality of preselected positions, comprising a longitudinally extending rack having spaced teeth and grooves carried by one of said members and an engagement pawl carried by the other of said members, said members being relatively movable inwardly toward each other and outwardly away from each other on an engagement path of travel between a pawl engaged position and a pawl disengaged position to engage and disengage said engagement pawl with said rack in the grooves between the teeth, means for first driving said members in a longitudinal relative movement to a preliminary selected relationship, and thereafter while said members are longitudinally at rest driving said members in said inwardly direction, and positioning means for moving said rack from said preliminary selected relationship longitudinally from an interference position in which a tip of said engagement pawl is aligned with an end of a tooth of said rack to another position in which the tip of said engagement pawl is at least slightly offset relative to the end of the tooth of said rack, said positioning means including a sensing pawl carried by said other member and disposed inwardly of said engagement pawl in a spaced-apart relationship with said rack when said engagement pawl is at the disengaged position, said sensing pawl including a tip with a pair of cam side surfaces extending therefrom, actuator means for moving said sensing pawl and rack into engagement when said rack is in the interference position and for pressing a cam side surface of said sensing pawl against a tooth of said rack to move said rack longitudinally from the interference position to the other position solely under influence of a force applied to said rack by said sensing pawl, said actuator means being operable to move said engagement pawl and rack into engagement after movement of said rack from the interference position to the other position by said sensing pawl to precisely locate said rack at a preselected position

2. The invention as defined in claim 1 wherein said sensing pawl is mounted for movement between an extended position wherein the tip thereof is inwardly of and laterally offset from the tip of the engagement pawl and a retracted position, and biasing means normally urging said sensing pawl to said extended position.

3. The invention as described in claim 2 wherein said sensing pawl is pivotally mounted with respect to said engagement pawl.

4. The invention as described in claim 1 wherein said engagement pawl is disposed for movement toward and away from said rack.

5. The invention as defined in claim 4 wherein said other member is mounted for pivotal movement for moving said engagement pawl into and out of engagement with said rack.

6. The invention as defined in claim 1 wherein said one member is rotatable to a plurality of positions and said other member is movable along said engagement path to engage said engagement pawl with said rack.

7. The invention as defined in claim 6 further characterized by means normally biasing said other member to a position wherein said engagement pawl is out of engagement with said rack, and cam means disposed to selectively urge said other member to move said engagement pawl into engagement with said rack.

8. The invention as defined in claim 6 wherein said one member includes means for performing embossments, and means to actuate said one member for embossment, and means to actuate said one member for embossment, and wherein said one member is rotatable on said positioning path of travel to select embossment characters, further characterized by means to operate said second member prior to the performing of the embossing operation.

Description:
This invention relates generally to registration devices and more particularly to registration devices for precisely positioning character-embossing dies and punches on embossing machines.

Although the invention has wider application, it will be described in conjunction with its use in embossing devices of the type shown in application, Ser. No. 784,558 filed Dec. 18, 1968 entitled Embossing Device.

In embossing machines of the type described in said application Ser. No. 784,558 a pair of embossing discs are provided which have radiating flexible fingers. The fingers are provided with mating punch and die sets for embossing characters on plastic or metal plates. The embossing discs are rotatable together on a shaft to move the desired punch and die sets to an embossing station, at which place the embossments on the plates are made. In order to determine which punch and die set is located at the embossing station, some type of external indicia and pointer system is provided.

In the embossing of plates or cards, especially the type that are to be used for addressing mail or for printing, such as credit cards, the spacing between the characters should be uniform. One of the factors effecting this uniformity is the exact position at the embossing station of each punch and die set. One of the easiest ways to obtain this exact positioning is by means of a rack-and-pawl mechanism. With this type of mechanism, a rack is normally formed in association with the discs or the shaft on which the discs are carried, and a pawl is provided to selectively engage the rack in the groove between the teeth. The spacing between the teeth and hence the spacing of the grooves is equal and each groove corresponds to one of the punch and die sets on the discs. The pawl moves to a given rack engagement position upon actuation. When the pawl is exactly aligned with the bottom of the groove, its movement into engagement will not move the rack either way. However, if the pawl is slightly out of alignment with the groove, it will strike one side of the tooth or the other and tend to rotate the rack, and hence the discs carried thereby to a position wherein the pawl upon the completion of its engagement movement is exactly in alignment with the bottom of the groove. This type of rack-and-pawl action for precise locating of a device is well known in the art.

However, there are some drawbacks to the above described rack-and-pawl positioning mechanism. One of the principal drawbacks to this type of mechanism is the action of the devices when the end of the pawl is substantially aligned with the tip of one of the teeth rather than between two teeth. When such alignment of the end of the pawl with the tip of the tooth occurs and the pawl starts forward for engagement with the rack, the end of the pawl will strike the tip of the tooth and will tend to bind thereon rather than shifting the rack to the right or left and engaging properly with the groove. When this happens, the punch and die sets on the discs are out of position at the embossing station, and an embossment in this position can ruin the entire article since it may tend to be a double embossment partly interferring with the previous embossment and partly offset. Even if the article is not completely ruined, substantial "erasure" or repair is required to correct the card.

There have been some prior art attempts to shape the pawl and the teeth of the rack to minimize the range over which the pawl will bind against the end of a tooth, but these have not eliminated the problem.

It is therefore, the principal object of this invention to provide a rack-and-pawl mechanism for precisely positioning a member which will minimize the tendency of a pawl to bind on the end of a tooth and will shift the rack properly.

Basically, this invention solves this problem by the provision of a compound pawl device which includes a sensing pawl adapted to shift a rack out of a position where the engagement pawl would normally bind on the end of a tooth to a position where the engagement pawl will fall between the teeth of the rack into a groove to allow proper shifting of the rack.

These and other objects, together with a fuller understanding of the invention, will become apparent from the following description taken in conjunction with the accompanying drawings in which:

FIG. 1 is a plan view partially in section showing an embossing machine incorporating a device of this invention;

FIG. 2 is a sectional view taken substantially along the plane designated by line 2--2 of FIG. 1;

FIG. 3 is a perspective view of the compound pawl mechanism;

FIGS. 4a, 4b, 4c and 4d are bottom plan views, somewhat schematic, showing in sequence the operation of the positioning device when the engagement pawl is in alignment with the tip of a tooth on the rack;

FIGS. 5a, 5b, 5c and 5d are views similar to FIGS. 4a, 4b, 4c and 4d, but showing the operation in sequence when the sensing pawl is aligned with the tip of a tooth of the rack.

Referring now the drawings, and for the present FIGS. 1 and 2, an embossing machine incorporating the rack-and-pawl registration device of this invention is shown. The embossing machine includes a base member 10 and a cover member 12. The cover member 12 has a depending shaft 14 on which a pair of embossing discs 16 and 18 are mounted for rotation. The discs 16 and 18 have radially extending fingers 16' and 18'. At the end of the fingers 16' and 18' are embossing dies 20 and embossing punches 22 respectively. Mating punch and die sets 20 and 22 are in alignment with each other so that they will emboss a character on an object held therebetween when the punch and die are squeezed together.

Rotation of the shaft 14 will rotate the discs 16 and 18 together, moving corresponding punch and die sets to an embossing station. An article A, to be embossed, is positioned between the punch and die sets 20 and 22 and can be advanced by a carriage mechanism 23. An embossment is made by actuating cam drive 24 which will raise an embossing head 25, causing the punch 22 at the embossing station to be raised. The coaction of the mating punch 22 and die 20 acting against an anvil 26, located at the embossing station squeezes an embossment into the article A.

An external pointer 27 is operably connected to the shaft 14 and indicia marking 28 are provided on the cover. As the shaft 14 rotates, the pointer 28 is driven by a cable and pulley system 29 along the indicia markings to indicate which character is at the embossing station.

However, because of many factors, a pointer and indicia markings are not satisfactory to get the precise position of the characters at the embossing station which is necessary. This precise positioning is accomplished by means of the coaction of a circular rack 30 and a compound pawl device 31 which, together constitute a registration device which will precisely and accurately position each punch and die set a the embossing station each time.

The rack 30 includes a plurality of circumferentially spaced teeth 32 which are equally and precisely spaced from each other with corresponding grooves 34 therebetween, the grooves also being equally and precisely spaced.

The compound pawl device, which can best be seen in FIGS. 2 and 3, includes a positioning member 40 pivotally mounted on and depending from a pivot pin 42 carried by a bracket 44. The bracket 44 is secured to the cover 12 by braces 45. The positioning member 40 includes a stem portion 46 terminating in an end assembly 48. The end assembly 48 includes an upper flange 50 and a lower flange 52. The flange 50 has a portion 50a extending laterally beyond the end of the flange 52. Where the flanges 50 and 52 are coextensive, they form a groove 53 therebetween.

The upper flange 50 has formed at the front edge thereof an engagement pawl segment 54a, and the lower flange 52 has a similarly shaped engagement pawl segment 54b formed thereon and in alignment with the pawl segment 54a. The pawl segments 54a and 54b together constitute an engagement pawl 54.

A pivot arm 58 is mounted on portion 50a of flange 50 by a pivot pin 60. The pivot arm 58 has an operating portion 62 disposed in the groove 53 between the flanges 50 and 52. The operating portion 62 has formed thereon a sensing pawl 64. The pivot arm 58 also has an extension portion 66 on the other side of the pivot pin 60 which is provided with a notch 68. A spring 70 extends between notch 68 and an anchor pin 72 projecting from the flange 50. Coacting stop surfaces 74 and 76 are provided on the pivot arm 58 covered by the bias of spring 70 (see FIG. 4a ). These stop surfaces are so positioned that when they are in contact, the sensing pawl is forwardly and laterally spaced with respect to the engagement pawl 54.

The positioning member 40 pivots about pin 42 to move the pawls 54, and 64 in and out of engagement with the rack 30 and is operated by means of an actuating mechanism designated generally as 78. The actuating mechanism 78 includes a link arm 80 connected to the positioning member 40 by a pin 81. The link arm 80 in turn is operated by a bifurcated actuating arm 82 pivotally mounted on a shaft 84. The arm 82 is slidably mounted to link arm 80 by a pin 86 residing in a slot 88 formed in the link arm 80. The actuating arm 82 is operable by a cam 90 bearing against a cam follower 92.

The actuating mechanism 78 is held in retracted position by means of a pair of springs 94 extending between the rear end of the bracket 44 and the actuating arm 82. Also a compression spring 96 is provided around the link arm 80 which, in conjunction with the pin 86 and slot 88, provides a lost motion mechanism.

When the character to be embossed has been selected by rotating the disc to bring the proper punch and die sets to the embossing station, the machine is actuated to cause the embossment. This actuation of the machine includes the actuation of the compound pawl device for the precise registration of the selected punch and die set. The compound pawl mechanism 31 is urged into engagement with the rack 30 by means of rotation of the cam 90 in a counterclockwise direction (as viewed in FIG. 2) when the embossing mechanism is actuated. The rotation of the cam 90 is synchronized so as to cause the compound pawl mechanism 31 to engage the rack 30 before closure of the die 22 against the article A is effected, as described in said application, Ser. No. 784,558.

As the cam 90 rotates in a counterclockwise direction, it bears against cam follower 92 causing the actuating arm 82 to also move in a counterclockwise direction pivoting about shaft 84. The action of the pivoting of the actuating arm 82 will cause the link arm 80 to pivot the positioning device 40 about pin 42 which will cause the pawls 54, and 64 to come into engagement with the rack 30. The engagement of the engagement pawl in the proper groove of the rack will precisely position the rack. Hence, precisely positioning the punch and die sets at the embossing station. FIG. 4a through 4d show in sequence the action of the compound pawl device on the rack where the engagement pawl 54 is in alignment with the tip of tooth 32a at the commencement of the embossing operation. In the absence of a sensing pawl, movement of the engagement pawl from the position shown in FIG. 4a into engagement with the rack would bring the tip of tooth 32a and the tip of pawl 54 into contact with the strong possibility that there would be insufficient lateral cam thrust to cause the rack to rotate. However, FIGS. 4b through 4d show how the sensing pawl 64 prevents this from happening.

FIG. 4b shown the positioning device 40 having pivoted to the position wherein the sensing pawl 64 just comes in contact with the rack 30. As can be seen, the sensing pawl 64 is forwardly of and laterally out of alignment with the engagement pawl. Since the sensing pawl 64 is forward of the engagement pawl 54, it strikes the tooth 32a first, and since the sensing pawl 64 is out of alignment with the engagement pawl 54, it is necessarily out of alignment with the tip of the tooth 32a. Thus, the pawl 64 rather than striking the tip of the tooth 32a, strikes the side edge of the tooth 32a and 32b. The force of the spring 70 is selected so that it is strong enough to overcome the frictional resistance of the rack 30 to movement. Therefore, continued movement of the positioning device 40 toward the rack 30 will cause the sensing pawl 64 to push against the side of tooth 32a. The rack 30 will move to the left. The pawl 64 will slide into the groove 34b to the position shown in FIG. 4c. The tip of the tooth 32a is moved out of alignment with the engagement pawl.

In the position shown in FIG. 4c, the sensing pawl 64 is at the bottom of the groove 34a and, hence, continued movement of the positioning device 40 toward the rack will cause the arm 58 to pivot against the bias of spring 70. This continued movement will cause the engagement pawl 54 to strike the edge of the tooth 32a, rather than the tip. Continued movement of device 40 from the position shown in FIG. 4c to the position shown in FIG. 4d will cause the engagement pawl 54 to first strike the edge of the tooth 32a and then push the rack to the left, sliding into groove 34b to the bottom thereof, as shown in FIG. 4d. The bottom portion of the engagement pawl 54 constitutes a precise positioning of the rack 30. In this position, the sensing pawl is fully retracted between the pawl segments 54a and 54b.

Continued movement of the cam 90 after this bottomed position of the engagement pawl 54 has been reached will be taken up by the lost motion mechanism.

When the embossment has been completed, the cam 90 is rotated back again to the position shown in FIG. 2, and the springs 94 withdraw the positioning device 40 from engagement with the rack 30.

FIGS. 5a through 5d show the action of proper positioning also being obtained when the sensing pawl 64 is in alignment with the tip of the tooth 32a at the start of the pawl movement.

FIG. 5b shows the positioning device 40 having been moved toward the rack 30 until the end of the sensing pawl 64 has engaged the tip of the tooth 32a. Since this will cause the sensing pawl 64 to bind against the tooth 32a, continued movement of the positioning device 40 from the position shown in FIG. 5b to the position shown in FIG. 5c will not cause the rack to rotate, but rather the arm 58 will pivot about pin 60 against the bias of spring 70. At the position shown in FIG. 5c, the sensing pawl 64 is fully retracted between the pawl segments 54a and 54b and the engagement pawl 54 is engaging the side of the tooth 32a defining groove 34c between the teeth 32a and 32c. Continued movement of the positioning device 40 from position shown in FIG. 5c to that shown in FIG. 5d will cause the rack to move to the right until the pawl 54 contacts the bottom of the groove 34c. This then constitutes a precise position of the rack 30.

FIGS. 4a through 4d and 5a through 5d shown only two of the infinite number of positions possible of the compound pawl device with respect to the rack when embossing is initiated. These two initial positions were selected because each represents a condition where a pawl is in line with the tip of a tooth which in the prior art constituted a potential binding situation. Thus, from the action of the device in these two positions, it can be seen that binding is virtually eliminated. It will be observed that, when the sensing pawl is located in a position where it will bind on the end of a tooth, the engagement pawl segments will be located to one side of the tooth and will properly engage in the groove between two teeth. However, when the sensing pawl is located where it will not bind on a tooth, it will shift the rack to a position where the engagement pawl segments will properly engage a groove between two teeth, even if initially the engagement pawl segments were aligned with the tip of a tooth. Thus, since the positioning device 40 always travels the same path for engagement and the rack is provided with equally spaced grooves, precise registration is achieved for each embossment, irrespective of any initial misalignment.

An examination of the drawings will show that it is possible in certain positions for the sensing pawl 64 to strike the right side of the tooth when the engagement pawl has been originally lined up on the left side of the tooth and which, in the absence of the sensing pawl, would be engaged in the groove 34c rather than 34b. However, because the sensing pawl moves the rack, the engagement pawl 54 will actually engage in groove 34c. It will be noted, however, that this condition exists only in a very narrow area or band between two adjacent characters and can be at least partially compensated for by proper calibration of the indicia with respect to the pointer. Further, the operator will be warned of an improper disc rotation by the movement of the pointer, but if not observed, it is preferable in these instances that a wrong character be embossed at the proper location which can then be erased, rather than a misaligned embossment which is difficult to erase.

It will be noted that there are slight involutions 98 (see FIG. 4a ) on each of the engagement pawl segments 54a and 54b. This configuration also aids in reducing binding of the engagement pawl 54 when the pawl strikes the left-hand side of a tooth.