Patent Publication Number: US-2004047669-A1

Title: Side knock or end knock mechanical pencil for thick lead

Description:
BACKGROUND OF THE INVENTION  
       [0001] The present invention relates to mechanical pencils.  
       [0002] A side knock type mechanical pencil including a cylindrical shell having a ferrule is shown in U.S. Pat. No. 6,099,182  
       [0003] U.S. Pat. No. 1,916,199 shows a square lead fixed in a holder that is not adjustable. U.S. Pat. No. 3,537,799 shows a mechanism for advancing a square lead with side sliding device. similar to yours but not for a side knock configuration), U.S. Pat. No. 6,099,182 (showing a well known side knock mechanism except with radial pinching for the small diameter lead). U.S. Pat. Nos. 2,274,311 and 4,505,606 show the use of an end knock or twist mechanism to push a square or rectangular lead out of a housing.  
       SUMMARY OF THE INVENTION  
       [0004] The present invention is a mechanical pencil with a side or end knock. An internal mechanism grasps a square or rectangular lead at a side location, holds it securely there so that lead extending beyond the pencil opening can be used, and permits the lead to be advanced in small increments without releasing the secure hold on the lead.  
       [0005] The types of lead that will be used in the invention device are well known in the art of construction. One of such leads is a rectangular cross section lead. Another is a square cross section lead. In a preferred example below, a lead with a cross section of about 5-6 millimeters by about 2-3 millimeters is used. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0006]FIGS. 1 and 2 are exploded and assembled perspective views of the invention pencil.  
     [0007] FIGS.  3 - 7  are respectively perspective external, flat and longitudinal side cutaway, narrow and longitudinal side cutaway, bottom end and cross section cutaway at the button opening views of the pencil housing.  
     [0008] FIGS.  8 - 10  are respectively perspective, front and bottom views of the pencil cap.  
     [0009] FIGS.  11 - 15  are respectively perspective, left side, front side, right side and bottom views of the invention back bush that secures the back of the pencil lead case within the housing.  
     [0010] FIGS.  16 - 21  are respectively perspective, front, right side, broad part cross section cutaway, top end, and narrow part cross section cutaway of the pencil lead case.  
     [0011] FIGS.  22 - 26  are respectively bottom perspective, top perspective, left, longitudinal side cutaway, and bottom views of the side knock button part of the pencil.  
     [0012] FIGS.  27 - 30  are respectively perspective, longitudinal side cutaway, top end and bottom end views of the pencil&#39;s body bush adapted to connect the pencil lead case with the front guide.  
     [0013] FIGS.  31 - 38  are respectively perspective, front, front side cutaway, left or right side, left or right side cutaway, bottom end, top end, and mid part cross section cutaway views of the front guide that secures and advances the pencil lead.  
     [0014] FIGS.  39 - 42  are respectively perspective, front, left or right side cutaway, front side cutaway, and bottom views of the front bush that secures and guides the pencil lead to the pencil&#39;s end opening for the lead.  
     [0015] FIGS.  44 - 46  are respectively perspective, side cutaway and bottom views of the cube ring that engages the top end of the front guide.  
     [0016]FIG. 47 shows the invention mechanism in a side cutaway view with the side knock button un-depressed.  
     [0017]FIG. 48 shows the invention mechanism in a side cutaway view with the side knock button depressed, urging the lead forward.  
     [0018]FIG. 49 is an exploded view of an invention embodiment similar to that of FIG. 1.  
     [0019]FIG. 50 is an side and cross section view of an invention embodiment similar to that of FIG. 48 with the button in the uncompressed position.  
     [0020] FIGS.  51 - 55  are respectively bottom side, side perspective, top end and top side views of piece  211   a  of the invention embodiment of FIG. 49 and operating directly and integrally with a button contact piece shown in FIG. 49, the two pieces forming the button.  
     [0021] FIGS.  56 - 60  are respectively side perspective, side, short side cross section, long side cross section, and end views of a body bush of an invention embodiment similar to the one in FIGS.  40 - 43 .  
     [0022] FIGS.  61 - 67  are respectively side perspective, short side, long side, short side cross section, long side cross section, bottom end and top end views of a front guide of an invention embodiment similar to the one in FIGS.  40 - 43 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
     [0023] The invention is now discussed with reference to the figures. The orientations of the invention described below are as if the mechanical pencil were vertical with the writing end at the bottom and the flat side of the pencil housing were facing the viewer, as in FIGS. 47 and 48.  
     [0024]FIG. 1 shows the invention pencil  100  with its parts exploded and in FIG. 2 as an assembled pencil with a rectangular lead  112  visible at its bottom end. FIG. 1 shows that cap end pieces  101  and  102  combine to cover the top end of the pencil by fitting snugly over the top end of the housing  110 . Encased in the housing  110  and capped with pieces  101  and  102  is the invention mechanism. Back bush  103  is adapted to secure the top end of lead case  104  against the pieces  101  and  102  so that lead case  104  is urged against the spring force of springs  105  that connect the bottom end of lead case  104  and securing lugs on body bush  106 . Front guide  108  holds and moves a lead  112  forward by being operated upon by body bush  106  holding a cube ring  107 , which ring  107  is secured in body bush  106  so that it can allow the front guide  108  to slide forward and back with respect to body bush  106  to compress and decompress a rectangular lead  112  on its long sides and advance the lead  112  upon depression of the lead advancing button  111 . Pinching arms of the front bush  109  generally hold and guide the lead  112  toward the opening in the housing  110  for the lead  112 .  
     [0025] FIGS.  3 - 7  are respectively perspective external, flat and longitudinal side cutaway, narrow and longitudinal side cutaway, bottom end and cross section cutaway at the button opening views of the pencil housing  110 , wherein an upper housing  110 - 1  is a flattened and rigid structure with an approximate oval cross section comprising body bush securing holes  110 - 2  for receiving projections from body bush  106  and button hole  110 - 3  for receiving in operational rotation the top of button  111 . The lower housing  110 - 5  comprises internal bores for the receiving and abutting securing outer surfaces of front bush  109  and forward outer surfaces of body bush  106 . Opening  110 - 4  is the opening for guiding and supporting lead  112  through the housing to make it available for use by the user. Another opening at the side of body bush  106  is adapted to receive a projection from button  111  so that button  111  rotates about that connection during operation of the pencil in advancing the lead  112 .  
     [0026] FIGS.  8 - 10  are respectively perspective, front and bottom views of the pencil cap  102 , wherein an oval and hollow body part  102 - 1  is adapted to be inserted into the top opening of housing  110 . Part  102 - 1  has extending from it extension  102 - 2  for securing the invention pencil in a pocket or on a belt.  
     [0027] FIGS.  11 - 15  are respectively perspective, left side, front side, right side and bottom views of the invention back bush  103  that secures the back of the pencil lead case  102  within the housing  110 . A back part  103 - 1  is adapted to secure within its capped U-shaped bore a top portion of the lead case  104  so that it is secured in a parallel relationship the axis of housing  110  for forward and back movement. The outer surface of back part  103 - 1  is adapted to rest securely against the inside of the housing  110  in the upper housing  110 - 1 . A top to middle part of lead case  104  is adapted to be slidingly secured in the bore of back part  103 - 1 . Forward arms  103 - 2  are adapted to engage the narrowed longitudinal outer surface of lead case  104 .  
     [0028] FIGS.  16 - 21  are respectively perspective, front, right side, broad part cross section cutaway, top end, and narrow part cross section cutaway of the pencil lead case  104 , which comprises a back guide for lead  112 , wherein a top body  104 - 1  has a cross section as seen in FIG. 19 and  20  with a bore  104 - 6  for holding multiple rectangular leads  112 , one of which is operatively passed to bore  104 - 5  as in FIG. 21, cross section of front end  104 - 3 . Front end  104 - 3  comprises lug  104 - 4  for securing ends of springs  105 , so that forward motion of the lead case  104  causes compression of the springs  105  against the securing lugs of body bush  106 . The broken line axis shown in FIGS. 17 and 18 is the broken line axis shown in other figures, but which represents the axis of rectangular lead  112  in operational engagement with the lead case  104 , body bush  106 , cube ring  107 , front guide  108 , front bush  108  and the opening of housing  110  for extrusion of lead  112 . Lead case  104  is adapted to have advancement ledges  104 - 2  on both sides of the case  104  to be abutted and engaged with button  111 &#39;s legs as they rotate in a forward motion that causes lead case  104  to move forward against the spring pressure of springs  105 . Opening  104 - 5  is adapted to receive the top end of front guide  108  so that its notches at that end snap fit into that end of the lead case  104 , where those notches are caused to just pass through the opening  104 - 5  to the greater diameter area above it.  
     [0029] FIGS.  22 - 26  are respectively bottom perspective, top perspective, left, longitudinal side cutaway, and bottom views of the side knock button  111 , wherein a top surface  111 - 1  is where the user presses with finger pressure to cause advancement of lead  112 . Legs  111 - 3  extend from the top surface  111 - 1  to engage ledges  104 - 2  (FIGS. 16 and 17) at angled edges. It is within the invention to make the ledges  104 - 2  substantially normal to the axis of lead  112  and the engaging edges of the legs  111 - 3  appropriately. Front lug  111 - 3  engages the above mentioned opening in the body bush  106  after lug  111 - 3  is passed through opening  110 - 3  (FIG. 4) to secure button  111  rotatingly at the lug with respect to the housing  110 . Extensions  111 - 4  extend from the outside surfaces of legs  111 - 3  further retaining button  111  in opening  110 - 3 .  
     [0030] FIGS.  27 - 30  are respectively perspective, longitudinal side cutaway, top end and bottom end views of the pencil&#39;s body bush  106  adapted to operatively connect the pencil lead case  104  motion to motion of the front guide  108 . Generally, body bush  106  abuts an outside surface of front part  106 - 1  against the inside front part  110 - 5  of housing  110 , and is further secured in housing  110  by notches  106 - 5  on extension  106 - 4  by snap fitting into holes  110 - 2  of housing  110  and causing button lug engaging extension  106 - 4  to abut the inside of the housing  110  opposite from holes  110 - 2 . Body bush  106  is secured very firmly in housing  110  in the assembled pencil. Spring engaging lugs  106 - 2  secure the ends of springs  105  that are opposite the lugs  104 - 4  on lead case  104  in the assembled pencil. Opening  106 - 6  receives cube ring  107  so that front guide  108  will be secured within it as described below.  
     [0031] FIGS.  31 - 38  are respectively perspective, front, front side cutaway, left or right side, left or right side cutaway, bottom end, top end, and mid part cross section cutaway views of the front guide  108  that secures and advances the pencil lead  112 . Front guide  108  is performs all the compression and decompression motion on the lead in the invention pencil. A top end  108 - 1  has an opening  108 - 5  for lead  112  to pass through without substantial compression. That opening extends to passage  108 - 11  and ending at an opening  108 - 12  at the bottom end of front guide  108 . Passage  108 - 11  comprises slots  108 - 4 , forming arms  108 - 2  that have increasing wedge compression sections  108 - 3 . Sections  108 - 3  are adapted to be compressed so that surfaces  108 - 10  press onto the long sides of lead  112  by the inside of cube ring  107  when sections  108 - 3  drawn into cube ring  107  and to expand away from the lead  112  when arms  108 - 2  are pushed out from it, as further described below. The at-rest position of front guide  108  is such that the sections  108 - 3  are compressed substantially completely within cube ring  104 , which is lodged in the opening  106 - 6  of body bush  106 . When front guide  108  is forced downward by action of depressing button  111 , cube ring  107  stays lodged in opening  106 - 6  and arms  108 - 2  emerge downward and expand away from lead  112  so that the lead is advanced. When button  111  is released from the depressed state, arms  108 - 2  retract into cube ring  107 , thereby re-establishing secure compression on the lead sufficient for writing with the pencil by a user. Retaining rims  108 - 8  are formed around at edges  108 - 9  of slot  108 - 4  so that the lead  112  will be guided toward the front bush  109 . Front guide  108  is preferably formed from an elastomer or other compressible material with substantial coefficient of friction to accomplish the objects of the invention.  
     [0032] FIGS.  39 - 42  are respectively perspective, front, left or right side cutaway, front side cutaway, and bottom views of the front bush  109  that secures and guides the pencil lead  112  to the pencil&#39;s end opening for the lead. The lead  112  emerging from the bottom end  108 - 12  of front guide  108  is moved toward the slotted opening in arms  109 - 1  that comprises narrowed neck  109 - 5 , which expands downward to passage  109 - 6 . Passage  109 - 6  is adapted to permit the lead  112  to move substantially without resistance and provides guidance and support for lead  112  as it moves from the bottom end of front guide  108  to the opening of the housing  110  for the lead  112 . Legs  109 - 3  are formed so that front bush rests securing inside the lower most cavity of housing  110  and so that opening  109 - 2  of passage  109 - 6  in lower section  109 - 4  is aligned with the housing  110  opening for lead  112 .  
     [0033] FIGS.  44 - 46  are respectively perspective, side cutaway and bottom views of the cube ring  107  that engages the sections  108 - 3  of arms  108 - 2  of the front guide  108 . Cylindrical or oval part  107 - 1  extends up from a stay rim  107 - 2 . Part  107 - 1  is located securely in opening  106 - 6  so that rim  107 - 2  abuts the bottom end of body bush  106  around that opening  106 - 6 . During all operations of the invention pencil, cube ring  107  remains in position within opening  106 - 6 .  
     [0034]FIG. 47 shows the invention mechanism in a side cutaway view with the side knock button  111  un-depressed and the pencil in a mode so that it can be used for writing. As described above, housing  110  supports and encases all the parts required for operation except for the lead  112  extended beyond the bottom opening of the housing  110  and the button  111  that is depressed and released by the user. Housing  110  holds lead case  104  and is supported with back bush  103  (not shown). An interface  111 / 104 - 2  is formed between the ledges  104 - 2  of lead case  104  and the forward edges of legs  111 - 3  of button  111 . It will be seen that downward motion of those forward edges will urge the entire body of lead case  104  downward an against the spring  105  pressure. Springs  105  (which may be encased in supporting plastic or metal cylinders) urge the structure attached to lugs  104 - 4  and  106 - 2  away from each other. Lead  112  is shown in broken lines, as are ledges  104 - 2 . Front guide  108  is snap fitted into the bottom end of lead case  104  so that it is drawn into cube ring  107 , which is in turn secured in the bottom end of body bush  106 .  
     [0035]FIG. 47 further shows that the sections  108 - 3  of front guide  108  have been drawn into the cube ring  107 , causing the greatest level of compression on the long sides of lead  112  between them. Lead  112  extends from the bottom end of body bush  108  to the top end of front bush  109 , thereafter extending through front bush  109  to the opening in housing  110  for lead  112 . The compression of lead  112  between surfaces  108 - 10  by arms  108 - 2  being drawn into cube ring  104  prevents lead  112  from being pushed back into lead case  104  when the user is writing with the invention pencil.  
     [0036]FIG. 48 shows the invention mechanism in a side cutaway view with the side knock button  111  depressed, urging the lead  112  forward. FIG. 48 is substantially the view of FIG. 47 with the button  111  depressed and showing the resulting action. Arms  108 - 2  of front guide  108  are extruded beyond the bottom opening of cube ring  107 , releasing substantial pressure on the lead  112  between surfaces  108 - 10  of sections  108 - 3 . The moving downward of front guide  108  causes lead  112  to be advanced and the gripping compression to be substantially reduced. When button  112  is released, lead  112  stays in substantially the location to which it was moved as shown in FIG. 48.  
     [0037] The invention embodiment of FIGS.  49 - 67  is similar in structure and operation to the embodiment of FIGS.  1 - 48 , where the aspect item numbers are only increased by 100 between them (i.e., the front bush  108  of FIGS.  31 - 38  is substantially similar in structure and operation as the front bush  208  of FIGS.  61 - 67 ). The changes to the embodiment of FIGS.  49 - 67  comprise the description below.  
     [0038] A lead case  204  with a narrowed front portion with a bore in about the front half that is about the cross sectional shape as that of a single lead  212  to be used in the pencil. This change more securely supports an engaged lead  212  (as in FIG. 50) within the case  204 , thereby also providing guidance for insertion of the lead  212  from the back end of case  204 . Another preferred dimension for a lead  212  to be used in the invention pencils is 70 mm(L)×2.5 mm(H)×5.0(W).  
     [0039] The changes made in the parts permit the invention pencil to be made substantially thinner at the housing  210  as compared with the housing  110  of the other embodiment.  
     [0040] Cap end pieces  201  and  202  are adapted to secure a magnet for support and storage of the invention pencil on a metal surface.  
     [0041] Button  211 / 211   a  comprises two parts instead of a single part  111 . The contact piece  211  is connected to piece  211   a  via a bar portion located on a top side. Piece  211   a  is adapted so that inward facing and opposing lugs on legs  111 - 3  (as in FIGS.  27 - 30 ). The changes in this embodiment permit more secure force transference from the button  211 / 211   a  to the lead case  204  to thereby cause lead  212  to advance according to the mechanism and structure as described above for the invention pencil.  
     [0042] The above design options will sometimes present the skilled designer with considerable and wide ranges from which to choose appropriate apparatus and method modifications for the above examples. However, the objects of the present invention will still be obtained by that skilled designer applying such design options in an appropriate manner.