Abstract:
A hand stamp is disclosed. The hand stamp comprises a frame including dove-tailed ribs which flare outwardly along at least one side thereof. The dove-tailed ribs of the frame are arranged within corresponding shaped grooves of a case, thus obtaining secure mounting of the case on the frame while facilitating relative slidable movement therebetween.

Description:
FIELD OF THE INVENTION 
   The present invention relates to hand stamps. More particularly, the present invention relates to hand stamps including a case securely mounted to a corresponding frame. 
   BACKGROUND OF THE INVENTION 
   Round hand stamps have been commercially available for many years. Such round hand stamps typically include a generally cylindrical configuration. Such hand stamps may be of the self-inking or pre-inked typed. 
   Self-inking hand stamps typically include an invertible stamp carrying platen and ink pad arranged within a frame. The platen may be connected to an impressible case which is slidably mounted on the frame. 
   The marking structure (i.e., the actual stamping member) of self-inking hand stamps are made of rubber or the like. They must be placed in contact with a source of ink, such as an internal ink pad, when the hand stamp is in a rest position. The ink pad may be permanently arranged within the hand stamp or may be removable. 
   Rubber marking structures used in self-inking hand stamps have a printing surface, which is typically arranged in contact with the ink pad when the hand stamp is in a rest position. The printing face of the marking structure is then typically moved and inverted along with a platen on which it is mounted through 180 degrees until it comes into contact with the desired surface to be printed—i.e., when the hand stamp is depressed into a printing position. 
   One brand of high-quality self-inking hand stamps is manufactured and sold by M&amp;R Marking Systems, Inc. under the trademark IDEAL®. Such self-inking hand stamps are discussed in prior art patents owned by M&amp;R Marking Systems, Inc. including U.S. Pat. Nos. 5,649,485; 4,852,489; and 4,432,281. 
   The self-inking hand stamps disclosed in the &#39;485, &#39;489 and &#39;281 patents have provided important commercial improvements in the hand stamp industry. Such improvements include, for example, a removable ink pad holder having re-inking ports on the back thereof; the ability to quickly and neatly replenish the ink supply of an associated ink pad; the ability to grasp the hand stamp from any direction; and advantages relating to displaying indicia information to be imprinted by the hand stamp. 
   While the foregoing self-inking hand stamps have been commercially successful and provided significant advantages, a need still exists for further improvements in self-inking and pre-inked hand stamp devices. 
   Pre-inked hand stamps include microporous marking structures, which are typically made of various polymeric materials and resin. These materials may comprise thermoplastic resin or other open cell compositions, such as specially formulated foam having a large quantity of microscopic pores. The microporous marking structure may be impregnated with ink or other suitable marking fluid during the manufacturing process or after it is manufactured. 
   Pre-inked hand stamps differ from self-inking hand stamps in that they do not need to include a separate ink pad as a source of marking fluid. Thus, pre-inked hand stamps can be used to create numerous ink impressions without requiring the user to introduce additional ink into the marking structure. This is possible due to the microscopic size of the pores, which allow the ink initially retained therein to escape at a controlled rate. 
   One brand of high-quality pre-inked hand stamps is manufactured and sold by M&amp;R Marking Systems, Inc. under the trademark ROYAL MARK®. These pre-inked marking structures are made from ROYAL MARK® brand gel, which comprises a mixture of thermoplastic resin and ink. Another well known brand of high-quality pre-inked hand stamps is marketed by M&amp;R Marking Systems, Ink under the trademark OPTIMARK®. The OPTIMARK® brand hand stamps include a microporous foam material as the marking structure. 
   Yet another brand of high-quality pre-inking hand stamps is manufactured and sold by M&amp;R Marking Systems, Inc. under the trademark ULTIMARK®. The ULTIMARK® brand hand stamps includes a microporous foam material, which has been impregnated with ink during the manufacturing process, as the marking structure. 
   Self-inking and pre-inked hand stamps exist in many geometric shapes and sizes. For some applications, it is desirable for the hand stamps to have a generally cylindrical configuration. Such cylindrical hand stamps are known as round hand stamps. When the round hand stamps are self-inking stamps, they are known are known round self-inkers. 
   Efforts have been made in designing round self-inkers to securely mount the case of the hand stamp to the frame. Typically, the platen is also secured to the case and is movable along with the marking structure secured thereon from a rest position, where the marking structure is in contact with an internal ink pad, to a printing position where the face of the marking structure becomes inverted and contacts the desired surface to be imprinted. 
   It is important in round self-inkers to secure the case to the frame such that the case will not become dislodged in the event that the hand stamp is accidentally dropped or a twisting force is applied when the hand stamp is operated. To meet this need, it is known for the case of the hand stamp to include ribs and the frame of the hand stamp to include cooperating grooves (e.g., slots) in which the ribs are arranged. In such an embodiment, the case is free to slide longitudinally along the frame as it is depressed during operation of the hand stamp. While it is desirable for the case to be fully slidable in the longitudinal direction (i.e., typically in the vertical direction), it is undesirable for the construction of the hand stamp to be such that the case can easily become dislodged if a twisting force is applied to it. 
   Round pre-inked hand stamps may have the same problems, but typically secure the case to the frame in a different manner as it is not necessary for the marking structure to have the same degree of movement and inversion as is the case in self-inking hand stamps. 
   SUMMARY OF THE INVENTION 
   The present invention overcomes shortcomings in the structure of prior art hand stamps. In accordance with a preferred embodiment of the present invention, a hand stamp comprises a frame, a case slidably mounted on the frame, a platen arranged for slidable movement with the case along the frame and an impression member arranged on the platen. As used herein the term “marking structure” should be construed broadly to comprise any suitable marking structure made of a natural or synthetic material used for self-inking or pre-inked hand stamps. For example, rubber marking structures are typically used with self-inking stamps such as the self-inking stamp shown in the drawings and described below in the preferred embodiments of the present invention. Microporous marking structures are typically used for pre-inked stamps. 
   The frame includes one or more dove-tailed ribs thereon while the case includes sized and shaped grooves corresponding with the dove-tailed ribs to facilitate secure mounting of the case to the frame while permitting slidable longitudinal movement therealong. As used herein, the term “dove-tailed ribs” shall mean ribs having at least one side that flares outwardly. The outward flaring of the ribs and the corresponding sized and shaped grooves in which the ribs are arranged can be more fully understood when considered in view of the drawings and the detailed description of the preferred embodiments set forth below. 
   The frame preferably includes at least a first rib longitudinally arranged thereon. The first rib may be molded to the frame and preferably includes at least one side, which flares outwardly from the frame. In this preferred embodiment, the case preferably includes at least a first groove and the first rib is arranged therein. The first groove and the first rib are sized and shaped to facilitate slidably longitudinal movement of the case along the frame, while obtaining secure mounting of the case on the frame. The platen is preferably arranged for slidable movement along with the case on the frame. A marking structure is arranged on the platen and is movable therewith between a rest position and a printing position. 
   The frame of the hand stamp preferably comprises a second rib longitudinally arranged thereon. Like the first rib, the second rib may be molded to the frame and is preferably dove-tailed. In this preferred embodiment, the case comprises a second groove in which the second rib is arranged. The second groove and the second rib are sized and shaped to facilitate slidable longitudinal movement of the case on the frame while securely mounting the case on the frame. 
   In an alternate embodiment, the first and second ribs may have different lengths. In particular, the length of the first rib may be greater than the length of the second rib or vice versa. 
   Preferably, the frame comprises opposing sides and one set of first and second ribs are arranged on each of the opposing sides. It is also preferable for the first and second ribs on each of the sides of the frame to have substantially the same length, although different length ribs can be provided as in the alternate embodiment discussed above. 
   The first set of first and second ribs are preferably arranged on one of the opposing sides of the frame while the second set of first and second ribs are arranged on the other of the opposing sides. In this preferred embodiment, the case comprises two sets of first and second grooves in which corresponding ones of the first and second ribs are arranged. 
   In the preferred embodiment where the frame comprises opposing sides and one set of first and second ribs are arranged on each of the opposing sides, the first and second ribs of one set preferably extend in the same plane as each other, while the first and second ribs of the other set will also extend in the same plane as each other. 
   It is preferable for the case to comprise a generally cylindrical configuration. However, in alternate embodiments, the geometric configuration of the case and the frame on which it is mounted may vary. 
   In a preferred embodiment, the marking structure comprises a rubber marking structure. The hand stamp may also comprise an ink pad against which the rubber marking structure is arranged when in its rest position. The rubber marking structure is then moved from the ink pad into contact with the surface to be imprinted when in its printing position. Thus, in such preferred embodiment, the hand stamp is a self-inking hand stamp. 
   In an alternate embodiment, the marking structure comprises a microporous marking structure such that the hand stamp is a pre-inked hand stamp. 
   It is also preferable for the hand stamp to comprise a locking mechanism operative to selectively lock the case in a desired position relative to the frame. The desired locked position may be one in which the ink pad of the hand stamp may be removed from assembled position and either re-inked or replaced. 
   In an alternate embodiment of the present invention, the location of the dovetailed ribs and corresponding grooves on the frame and the case of hand stamp may be reversed. Thus, in such alternate embodiment, the dovetailed ribs may be arranged on the case and the corresponding shaped grooves may be arranged on the frame of the hand stamp. 
   The above features and advantages of the present hand stamp will be more fully appreciated when considered in view of the following detailed description of the preferred embodiments and accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of a preferred embodiment of a hand stamp in assembled position. 
       FIG. 2  is the bottom perspective view of the hand stamp of  FIG. 1 . 
       FIG. 3  is an enlarged perspective view of the area designated Detail A in  FIG. 2 , showing the connection between the frame and case of the present hand stamp. 
       FIG. 4  is a bottom plan view of the hand stamp of  FIG. 1 . 
       FIG. 5  is a perspective side view of the frame component of the hand stamp shown in  FIG. 1 . 
       FIG. 6  is a perspective bottom view of the case component of the hand stamp of  FIG. 1 . 
       FIG. 7  is cross sectional view of the present hand stamp shown in its rest position taken along line VII—VII of  FIG. 1 . 
       FIG. 8  is a cross sectional view of the hand stamp of the present invention shown in a fully compressed printing position. 
       FIG. 9  is a bottom perspective view of an alternate embodiment of the frame of the present hand stamp showing ribs of different lengths. 
       FIG. 10  is a perspective side view of a frame in accordance with an alternate embodiment of the present hand stamp. 
       FIG. 11  is a perspective bottom view of a case corresponding with the frame of  FIG. 10 . 
   

   DETAILED DESCRIPTION 
   Preferred embodiments of the hand stamp  10  in accordance with the present invention is shown in  FIGS. 1–11 . The hand stamp  10  is shown as a self-inking hand stamp. However, the present invention also applies to pre-inking hand stamps and thus, the description of the preferred embodiments herein is not intended to limit the scope of the present invention to self-inking hand stamps. 
   The hand stamp  10  includes a frame  12  as shown in  FIGS. 1–5  and  7 – 9 . The frame  12  has a bottom end  14  and a top end  16 . When assembled, the top end  16  of the frame  12  cannot be seen. However, top end  16  is visible in  FIG. 5 , which illustrates an isolated perspective view of the frame  12 . 
   As best shown in  FIGS. 1 and 7 , the frame  12  includes an opening  18  which extends through the front face thereof and an aligned opening  20 , which extends through the rear face thereof. In alternate embodiments, the front and rear faces of the frame may be solid. 
   Right and left side slots  22  and  24  are shown in  FIGS. 1–5  and  7 . The slots  22  and  24  are sized and shaped to receive corresponding posts extending outwardly from opposing sides of a platen  54  and cooperating runners of a case  58  as discussed below. 
   A significant aspect of the present hand stamp  10  relates to the geometric configuration of ribs arranged on the frame  12  within cooperating grooves arranged in the case  58 . In particular, the frame  12  includes a pair of ribs  26  and  28  extending parallel to each other on the right side thereof. These ribs may be considered first and second ribs, respectively on the right side of the frame  12 . In the preferred embodiment described herein and shown in  FIGS. 1–8 , the first and second ribs  26  and  28  are identical to each other in both length and geometrical configuration. 
   In an alternate embodiment, the geometric configuration and length of the ribs need not be identical. For example  FIG. 9  shows an alternate embodiment including frame  112  where each side includes opposing ribs  126  and  128  having different lengths. A significant aspect of ribs  26  and  28  is that they are dove-tailed (i.e., flared out) on at least one side thereof. For example, rib  26  is dove-tailed as indicated by reference numeral  30  on one side thereof. The other side of rib  26  is substantially flat as indicated by reference numeral  32 . Similarly, rib  28  is dove-tailed such that it is flared out on one side as indicated by reference numeral  34 , but the other side  36  is flat. 
   The left side of frame  12  is substantially identical to the right side as it includes a pair of identical ribs  38  and  40 . First left side rib  38  is dove-tailed as indicated at  42  and is flat as indicated at  44 . Similarly, the second left side rib  40  is also dove-tailed as shown at  46  and is flat as shown at  48 . 
   The dove-tailed feature of the pairs of ribs  26 ,  28  and  38 ,  40  provides structural integrity to retain the case  58  in a secured position on the frame  12  while facilitating longitudinally slidable movement between the case  58  and frame  12 . 
   The frame  12  also includes an opening  50  for insertion and removal of a corresponding inkwell  52  as shown in  FIGS. 7–8 . The platen  54  and corresponding rubber marking structure  56  are also shown in the cross sectional views of  FIGS. 7–8 . 
   Another significant aspect of the present hand stamp  10 , includes features of the case  58 , which is securely mounted for slidable movement on the frame  12 . As shown in FIGS.  1  and  7 – 8 , the case  58  includes a generally cylindrical body  62  and a circular top  60 . The case  58  also includes a right side extension arm  64  and a left side extension arm  66 , which oppose each other and extend downwardly along the associated frame  12 . 
   A pair of locking buttons  68  and  70  are arranged at respective right and left sides of the case  58  as shown in  FIGS. 1–4 ,  6  and  7 . The locking buttons  68  and  70  allow a user to selectively lock the case in certain positions with respect to the frame  12  to permit removal of the inkwell  52  for re-inking or to retain the case in a depressed position for storage. Alternate embodiments of the invention may include only a single locking button or may not include any locking button. 
   The right side extension arm  64  includes a central runner  72 , which extends into the right side slot  22  of frame  12 . Similarly, the left side extension arm  60  of case  58  includes a central runner  74 , which is arranged within left side slot  24  of frame  12 . The runners  72  and  74  may be eliminated in alternate embodiments of the invention. 
   A significant aspect of the present invention relates to the size and shape of grooves  76 ,  78 ,  80  and  82  arranged within the right and left side extension arms  64  and  66  of case  58 . More particularly, a first pair of grooves  76  and  78  are clearly shown in  FIGS. 2–4 ,  6  and  7  as having a substantially flat side and an outwardly flared side to accommodate the dove-tailed shape of corresponding first and second ribs  26  and  28 . As the case  58  is symmetrical, the left side extension arm  66  includes corresponding grooves  80  and  82 , which also are flared at one side and flat at the other to cooperate with the size and shape of corresponding ribs  38  and  40 . 
   When the hand stamp  10  is fully assembled such that the case  58  and frame  12  are connected, the dove-tailed ribs  24 ,  26 ,  38  and  40  are arranged within corresponding grooves  76 ,  78 ,  80  and  82  to facilitate slidable movement of the case  58  along the frame  12 . This will permit a user to operate the hand stamp  10  when it is desired to create an ink impression upon movement of the marking structure  56  from its rest position, where its face is in contact with inkwell  52  to its printing position where its face contacts a surface and imprints an ink design thereon. 
   The dove-tailed configuration of ribs  26 ,  28 ,  38  and  40  and cooperating flared grooves  76 ,  78 ,  80  and  82  provide structural integrity by securely mounting the case  58  to the frame  12 . Thus, the combination of the ribs and grooves serve to prevent the case  58  from being removed from the frame  12  in the event that the case  58  is inadvertently twisted or in situations where the hand stamp  10  is dropped. 
     FIG. 7  shows a cross sectional view of hand stamp  10  taken along line VII—VII of  FIG. 1 . This cross sectional view is indicative of hand stamp  10  when arranged in a rest position and thus, the face of the marking structure  56  is retained in contact with the inkwell  52  within the frame  12 . Further, the platen  54  is shown to be connected to frame  12  via opposing posts  55 , which extend through apertures  65  and  67  arranged through right and left extension arms  64  and  66 , respectively. 
     FIG. 8  is a cross sectional view of the hand stamp  10 , illustrating the hand stamp  10  when compressed into its printing position such that the face of marking structure  56  is in contact with the surface of an object to be imprinted with the desired ink design. 
   An alternate embodiment of the present invention reverses the location of the dovetailed ribs and corresponding grooves on the frame and case of the hand stamp.  FIGS. 10 and 11  illustrate such alternate embodiment where the dovetailed ribs are arranged on the case and the corresponding shaped grooves are arranged on the frame. 
     FIG. 10  illustrates a perspective view of a frame  212  having two sets of grooves  276 ,  278  and  280 ,  282  arranged on the right and left sides, respectively. The size and shape of grooves  276 ,  278 ,  280  and  282  correspond closely with the size and shape of dovetailed ribs arranged on the case  258  illustrated in  FIG. 11 . Centrally arranged slots  222  and  224  are illustrated on the right and left sides of frame  212 . As also shown in  FIG. 10 , frame  212  includes a top end  216 , a bottom end  214  and an opening for an inkwell  250 . 
     FIG. 11  illustrates that a case  258  includes two so sets of dovetailed ribs,  226 ,  228  and  238 ,  240  arranged on the right and left sides, respectively. The other features of the case  258  are identical to the features of the case  58  shown in  FIG. 6 . Thus, case  258  includes right and left side extension arms  264  and  266 . The case  258  includes a generally symmetrical cylindrical body  262 . The pairs of dovetailed ribs  226 ,  228  and  238 ,  240  are sized and shaped to be mounted within corresponding grooves  276 ,  278  and  280 ,  282  such that the case  258  is securely mounted on the frame  212  for slidable movement in substantially the same manner as the corresponding case  58  and frame  12  of  FIGS. 1–8 . 
   Although the invention herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims.