Abstract:
A method for raising and lowering the feed and delivery tables of a printing press utilizes a drive-limiting tool which is attached to a conventional drill motor. The combination is used to turn the rotatable member of the printing press which in turn through the table&#39;s raising and lowering mechanism raises and lowers the feed table. The drive-limiting tool ensures that the table raising and lowering mechanism is not overdriven. It does so by automatically slipping off of the rotatable member of the printing press when the table raising and lowering mechanism reaches its upper and lower limits.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a continuation-in-part of application Ser. No. 09/645,742, filed Aug. 24, 2000, now abandoned and which is included herein by reference. 
    
    
     TECHNICAL FIELD 
     The present invention pertains generally to the printing industry, and more particularly to a method for rapidly raising and lowering the feed and delivery tables of a printing press. 
     BACKGROUND OF THE INVENTION 
     When sheets of paper are run through a printing press, the process is known as feeding. When paper is placed into the press the process is known as loading. When paper is placed into the press the paper is placed onto a platform called a feed table. The exact point at which paper is fed into the press to be printed upon by the machine is approximately 3 feet off of the ground. Before paper can be loaded into the press for printing the feed table must be lowered approximately 2.5 feet via means of a chain system operated by a crank handle. To lower the table 2.5 feet the crank must be turned approximately 55 revolutions as quickly as possible to limit non-production time or down time. After a while this can become quite tiresome and repetitive. The act of raising or lowering the feed and delivery tables also requires the operator to be in a bent over posture causing strain on the printing press operator&#39;s back. 
     For example assume that an order was received for 50,000 #10 printed envelopes. #10 envelopes can only be printed 500 at a time. To run this order, 500 unprinted envelopes are placed upon the lowered feed table to be printed. The feed table must then be raised by the crank handle until the top of the stack of envelopes reaches the correct point where the printing press is able to draw the top envelope into the press via an air suction system to be printed. As the envelopes are constantly pulled into the press to be printed the stack is depleted. At these times the press has a device known as a bale bar which moves in an up and down motion, the down motion stops when the bale bar comes in contact with the top of the stack of paper which is constantly depleting due to paper or envelopes being pulled into the printing press to be printed. The feed table is then automatically raised by the press in small increments to keep the upper most sheets of the stack of paper, envelopes etc. in the correct position to be fed into the press for printing. To print on 50,000 envelopes 500 at a time (100 boxes of #10 envelopes) the feed table must be lowered by the hand crank a total of 5,500 revolutions. To use the handle it must be pushed in where two squared cutouts on the inside of the handle intersect with two squared outcroppings on the printing press and held in place. The handle is not permanently attached to the printing press, however it is normally left in position to perform the cranking operation. 
     Also, where the paper comes out of the printing press, it lands on another table known as the delivery table. This table is very similar to the feed table. The delivery table can be set to go down as the amount of printed sheets accumulate. Once the table reaches the bottom, the printed materials are removed and the table must be re-raised by another hand crank. 
     Devices for assisting in manual cranking or turning operations are well known in other art fields. For example, U.S. Pat. No. 2,465,048 shows a wrench head for tightening wing nuts which is adapted to be driven by a rotating tool such as a torque screwdriver or the like. The invention tightens wing nuts with improved speed and efficiency. 
     U.S. Pat. No. 3,086,414 is directed to a combination wrench of the socket type having a cylindrical stem, a free end having an axial bore of a diameter sufficient to provide clearance for the screw to which a nut is to be threaded, and plurality of cut away portions. 
     U.S. Pat. No. 3,868,874 illustrates an insulative torque coupling assembly for electrical device terminals. The device includes a bolt engaging a bolt passing through an aperture in a terminal of an electrical device. U.S. Pat. No. 4,984,489 defines a window handle turning drive-limiting tool for a hand drill which cooperates with the crank handle of the opening mechanism of a casement window. The drive-limiting tool includes a shaft which is intended to be gripped by the chuck or jaws of the hand drill in much the same manner that hand drills grip drill bits. A forwardly projecting crank handle-contacting head is provided which is adapted to slide over the crank handle. 
     U.S. Pat. No. 4,846,025 pertains to a tool for removing radiator caps. The tool has a hollow handle and a flanged hollow face. The hollow face has a recess with a perimeter. The perimeter has a pair of opposed rectangular indentations, at least one pair of opposed arcuate indentations, and a pair of tapering indentations which interrupt the perimeter to form a pair of opposed openings. 
     U.S. Pat. No. 5,433,850 discloses an adapter to operate a honey extractor utilizing a power drill. The adapter engages the drive shaft axially of the honey extractor after removal of the handle which is used for manual operation to connect the drive shaft to a power drill. The adapter is conveniently a socket to engage an end of the drive shaft, the socket having a prong for insertion in the chuck of the power drill. 
     U.S. Pat. No. 5,697,268 portrays a wing nut driver. The device includes a cylindrical housing having a bore at one end for receiving the wing nut therein. 
     U.S. Pat. No. 5,896,785 comprises an automobile gas cap removal tool, formed of plastic aluminum having a bell shape with channel formed by the wall segments and a pillar or shaft extending from the top of the bell segment to a handle mounted on the opposite end of the pillar extending from the bell segment. 
     U.S. Pat. No. 5,996,447 consists of a sink wrench for engaging a faucet mounting nut, the wrench including an elongated tubular pipe which has slots at one end. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to a method for using a drive-limiting tool to raise and lower the feed and delivery tables of a printing press. The tool, in combination with a power drill, replaces the manual hand crank which is classically used to raise and lower the tables. The present invention eliminates operator fatigue, increases production, reduces down time, and increases employee moral which comes with the knowledge of not having to crank the feed or delivery table handles any longer. The drive-limiting tool of the present invention is inserted into a common hand held multi-speed reversible phased power drill and firmly secured with a chuck key. The printing press crank handles are removed and the drive-limiting tool is aligned with the rotatable member on the printing press. The feed and delivery tables can then be raised or lowered using the power drill. The speed of the raising or lowering of the feed and delivery tables is increased by a factor of about four depending on the power of the drill. When the tables reach either the top or the bottom in the printing press they come to a halt. The beveled edges allow the drive-limiting tool to “pop out” and not damage the printing press. 
     Advantages of the Present Invention: 
     The drive-limiting tool of the present invention replaces the hand cranks on the feed and delivery tables of small offset printing presses. 
     It can be used alternately on the feed table drive or the delivery table drive on any number of printing presses without installation. 
     Eliminates operator fatigue, increases production, decreases downtime and increases employee moral which comes with the knowledge of not having to crank the feed or delivery tables any longer. 
     The drive-limiting tool is constructed of aluminum which is a softer metal than the printing press is constructed of thereby preventing undue wear and tear to valuable printing equipment. 
     The drive-limiting tool can be used with the feed or delivery drives on numerous types of printing presses without installation and is simple to use. Some types of presses the drive-limiting tool could be used with include the Ryobi 3302M, Ryobi 3200CD, Ryobi 3200NP, Itek 3985, Itek 960, Itek 975 and can be easily redesigned to fit other small printing presses such as Hamada printing presses, Multigraphic printing presses, Heidleberg printing presses and AB Dick printing presses to name a few. 
     The drive-limiting tool also greatly increases the speed of the raising and lowering of the feed and delivery tables. 
     In accordance with a preferred embodiment of the invention, a method for raising and lowering a table of a printing press, includes: 
     (a) providing the printing press having a rotatable member for raising and lowering the feed and delivery tables, the rotatable member having a longitudinal axis, two spaced protuberances having walls disposed substantially parallel to the longitudinal axis of the rotatable member, and a central outwardly projecting shaft, the table having an uppermost position and an opposite lowermost position and a table raising and lowering mechanism, wherein the rotatable member can only raise or lower the table between the uppermost and lowermost positions, and the rotatable member experiencing rotational resistance and ceasing to rotate when the table reaches either of the uppermost or lowermost positions; 
     (b) providing a drive-limiting tool having: 
     a front portion; 
     an opposite rear portion; 
     a longitudinal axis; 
     the front portion shaped and dimensioned to engage the rotatable member of the printing press; 
     the front portion having a slot for receiving the two spaced protuberances; 
     the front portion having a central hole for receiving the central outwardly projecting shaft; 
     the slot having two outwardly opening walls which slope outwardly with respect to the longitudinal axis of the drive-limiting tool; and, 
     the rear portion having an axially projecting drive shaft; 
     (c) providing a power drill; 
     (d) installing the drive shaft of the drive-limiting tool in the power drill; 
     (e) engaging the rotatable member with the front portion of the drive-limiting tool; 
     (f) activating the power drill so that the drive-limiting tool rotates the rotatable member; 
     (g) continuing to activate the power drill until the table reaches one of the uppermost position and the lowermost position wherein the rotatable member experiences rotational resistance and ceases to rotate; and, 
     (h) when the rotational member ceases to rotate, because of the slope of the walls of the slot, the walls are urged away from the protuberances thereby causing the drive-limiting tool to disengage from the rotatable member, thereby preventing the table raising and lowering mechanism from being overdriven. The disengagement also prevents damage to the power drill, and possible injury to the printing press operator. 
     Other features and advantages of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS 
     FIG. 1 is a top plan view of a drive-limiting tool for a printing press in accordance with the present invention; 
     FIG. 2 is a side elevation view of the drive-limiting tool; 
     FIG. 3 is a bottom plan view; 
     FIG. 4 is a perspective view of the drive-limiting tool; 
     FIG. 5 is a reduced side elevation view of the drive-limiting tool being placed in a power drill; 
     FIG. 6 is a reduced side elevation view of the drive-limiting tool in the power drill engaging a rotatable member of the printing press; 
     FIG. 7 is a top plan view of a second embodiment of the drive-limiting tool; 
     FIG. 8 is a side elevation view of the second embodiment drive-limiting tool; 
     FIG. 9 is a bottom elevation view of the second embodiment drive-limiting tool; 
     FIG. 10 is a perspective view of the second embodiment drive-limiting tool; 
     FIG. 11 is a reduced side elevation view of the second embodiment drive-limiting tool being placed in a power drill; 
     FIG. 12 is a reduced side elevation view of the second embodiment drive-limiting tool in the power drill engaging the rotatable member of the printing press; 
     FIG. 13 is a fragmented side elevation view of a rotatable member of a printing press; 
     FIG. 14 is a top plan view of the rotatable member; 
     FIG. 15 is a fragmented side elevation view of the rotatable member rotated 90° from FIG. 13; 
     FIG. 16 is a top plan view of a manual rotation shaft; 
     FIG. 17 is a fragmented side elevation view of the manual rotation shaft; 
     FIG. 18 is a fragmented side elevation view of a second embodiment rotatable member of a printing press; 
     FIG. 19 is a top plan view of the second embodiment rotatable member; 
     FIG. 20 is a top plan view of a second embodiment manual rotation shaft; 
     FIG. 21 is a fragmented side elevation view of the second embodiment manual rotation shaft; 
     FIG. 22 is top plan views of another embodiment of the drive-limiting tool; 
     FIG. 23 is a side elevation view of the embodiment of FIG. 22; 
     FIG. 24 is a bottom plan view of the embodiment of FIG. 22; and, 
     FIG. 25 is a functional diagram showing how the printer table is driven. 
    
    
     DETAILED DESCRIPTION OF INVENTION 
     Referring initially to FIGS. 13-15, there are illustrated fragmented side elevation, top plan, and rotated fragmented side elevation views respectively of a prior art rotatable member of a printing press, generally designated as  500 . One rotatable member  500  is mechanically connected to the feed table of the printing press, so that when rotatable member  500  is rotated with a manual rotation shaft  600  (refer to FIGS. 16-17) which is connected to a rotation handle, the feed table may be raised or lowered. The direction of rotation determines whether the feed table is raised or lowered. Another rotatable member  500  is similarly mechanically connected to the delivery table of the printing press. Rotatable member  500  has two spaced protuberances  502 , each having a width w. Rotatable member  500  also has a centrally projecting shaft  504 . 
     Referring now to FIGS. 16-17, there are illustrated top plan and fragmented side elevation views respectively of a manual rotation shaft, generally designated as  600 . Manual rotation shaft  600  is connected to a rotation handle (not shown). Manual rotation shaft  600  has a slot  602  for receiving two spaced protuberances  502  of rotatable member  500  (refer to FIGS.  13 - 15 ). Manual rotation shaft  600  also has a hole  604  for receiving projecting shaft  504  of rotatable member  500 . When it is desired to raise or lower the feed or delivery tables of the printing press, manual rotation shaft  600  (and handle) engages rotatable member  500 , and rotatable member  500  is rotated to effect the raising or lowering of the table. In normal usage, manual rotation shaft  600  and the handle remain connected to rotatable member  500 . 
     The mechanical configurations shown in FIGS. 13-17 may be found in Multigraphics/Multilith printing presses, and also in Ryobi/Itek and Hamada printing presses. 
     Referring now to FIGS. 18-19, there are illustrated fragmented side elevation and top plan views of a second embodiment prior art rotatable member, generally designated as  700 . One rotatable member  700  is mechanically connected to the feed table of the printing press, so that when rotatable member  700  is rotated with a manual rotation shaft  800  (refer to FIGS. 20-21) which is connected to a rotation handle (not shown), the feed table may be raised or lowered. The direction of rotation determines whether the feed table is raised or lowered. Another rotatable member  700  is similarly mechanically connected to the delivery table of the printing press. Rotatable member  700  has three circular holes  702  each having a diameter d. Three holes  702  surround an outwardly projecting shaft  704 . 
     Referring now to FIGS. 20-21, there are illustrated top plan and fragmented side elevation views respectively of a second embodiment manual rotation shaft, generally designated as  800 . Manual rotation shaft  800  is connected to a rotation handle (not shown). Manual rotation shaft  800  has a protuberance  802  for engaging one of the holes  702  of rotatable member  700  (refer to FIGS.  18 - 19 ). Manual rotation shaft  800  also has a hole  804  for receiving projecting shaft  704  of rotatable member  700 . When it is desired to raise or lower the feed or delivery tables of the printing press, manual rotation shaft  800  (and handle) engages rotatable member  700 , and rotatable member  700  is rotated to effect the raising or lowering of the table. In normal usage, manual rotation shaft  800  and the handle remain connected to rotatable member  700 . 
     The mechanical configurations shown in FIGS. 18-21 may be found in AB Dick 300 &amp; 9800 series printing presses. 
     Referring now to FIGS. 1-4, there is illustrated top plan, side elevation, bottom plan, and perspective views respectively of a drive-limiting tool for a print press in accordance with the present invention, generally designated as  20 . Drive-limiting tool  20  includes a socket-like body  22  having a front portion  24  and an opposite rear portion  26 . Front portion  24  has two spaced cavities (or slots)  28  for receiving the spaced protuberances  502  of rotatable member  500  (refer to FIGS.  13 - 15 ). Spaced cavities  28  each are defined by two outwardly opening (beveled) walls  30 . By having outwardly opening walls  28 , drive-limiting tool  20  cannot overdrive rotatable member  500 , such as at the top or bottom of the table run. That is, if too much rotational force is exerted upon rotatable member  500 , the two spaced protuberances  502  will ride up the slopping walls  30  and disengage drive-limiting tool  20  from rotatable member  500 . Front portion also has a central hole  32  for receiving the outwardly projecting shaft  504  of rotatable member  500  (refer to FIGS.  13 - 15 ). Rear portion  26  has an axially projecting drive shaft  34  having a longitudinal axis  31 . Outwardly opening walls  30  slope outwardly with respect to longitudinal axis  31 . In a preferred embodiment two spaced cavities  28  are formed by a first slot (shown by line  36 ) in said front portion  24 . Also in a preferred embodiment, front portion  24  has a second slot (shown by line  38 ) intersecting first slot  36  at a substantially right angle. By having two substantially perpendicular slots  36  and  38 , it is easier to engage spaced protuberances  502  of rotatable member  500 . First slot  36  has a bottom portion having a width W which is slightly greater than the width w of the two spaced protuberances  502 , so that the two spaced protuberances may be received by first slot  36 . In a preferred embodiment, width W of the bottom portion is about 0.25 inches. Also in a preferred embodiment, two outwardly opening walls  30  slop at an angle of about 30° with respect to longitudinal axis  31 . 
     FIG. 5 is a reduced side elevation view of drive-limiting tool  20  being placed in a bi-directional power drill  900 . Drive shaft  34  is placed in the chuck of power drill  900  and the chuck tightened. 
     FIG. 6 is a reduced side elevation view of drive-limiting tool  20  installed in power drill  900 , and engaging rotatable member  500  of the printing press. 
     Referring now to FIGS. 7-10, there is illustrated top plan, side elevation, bottom plan, and perspective views respectively a second embodiment of a drive-limiting tool for a printing press in accordance with the present invention, generally designated as  120 . Drive-limiting tool  120  includes a socket-like body  122  having a front portion  124  and an opposite rear portion  126 . Front portion  124  has three rounded substantially hemispherical protuberances  128  for engaging the three holes  702  in rotatable member  700  (refer to FIGS.  18 - 19 ). By having rounded protuberances  128 , drive-limiting tool  120  cannot overdrive rotatable member  700 , such as at the top of bottom of the table run. That is, if too much rotational force is exerted upon rotatable member  700 , the three rounded protuberances  128  will disengage drive-limiting tool  120  from rotatable member  700 . Front portion  124  also has a central hole  132  for receiving the outwardly projecting shaft  704  of rotatable member  700  (refer to FIGS.  18 - 19 ). Rear portion  126  has an axially projecting drive shaft  134 . Three rounded protuberances  128  each have a diameter D which is slightly less than the diameter d of holes  702  in rotatable member  700 . In a preferred embodiment, protuberances  128  have a diameter of about 0.25 inches. 
     FIG. 11 is a reduced side elevation view of the second embodiment drive-limiting tool  120  being placed in a bidirectional power drill  900 . 
     FIG. 12 is a reduced side elevation view of the second embodiment drive-limiting tool  120  installed in the power drill  900 , and engaging the rotatable member  700  of the printing press. 
     FIGS. 22-24 are top plan, side elevation, and bottom plan views respectively of another embodiment of drive-limiting tool  20 . This embodiment is similar to the embodiment of FIGS. 1-4 with the exception that in this embodiment drive-limiting tool  20  only has one cavity or slot  28  for engaging rotatable member  500 . 
     FIG. 25 is a functional diagram showing how the printer table is driven. Rotatable members 500/700 drive table raising and lowering mechanism  550 , which in turn raises or lowers feed or delivery table  560  between uppermost position  570  and lowermost position  580 . 
     In a preferred embodiment, the drive-limiting tool is fabricated from aluminum or some other suitable metal. A polymer could also be utilized. 
     In terms of use, a method for raising and lowering a feed or delivery table of a printing press includes the steps of (refer also to FIGS. 1-6, and  13 - 25  as described above); 
     (a) Providing a printing press having rotatable members  500  connected to both its feed and delivery tables  560 , the rotatable member  500  for raising and lowering the respective tables  560 , said rotatable member  500  having a longitudinal axis  505 , two spaced protuberances  502  having walls  503  disposed substantially parallel to longitudinal axis  505  of rotatable member  500 , and a central outwardly projecting shaft  504 , table (feed or delivery)  560  having an uppermost position  570  and an opposite lowermost position  580 , wherein rotatable member  500  can only raise or lower the table  560  between the uppermost  570  and the lowermost  580  positions. That is, as rotatable member  500  is turned the table  560  moves according to the direction of rotation until either the uppermost  570  or lowermost  580  position is reached. At either of these extreme positions, the table raising and lowering mechanism  550  reaches its limit and can move no more, therefore rotatable member  500  experiences rotational resistance and ceases to rotate (i.e. cannot be rotated further). Continued attempts to forcibly rotate rotatable member  500  can overdrive and consequently damage the table&#39;s raising and lowering mechanism  550 . 
     (b) Providing a drive-limiting tool  20 . Drive-limiting tool  20  having a front portion  24 , an opposite rear portion  26 , and a longitudinal axis  31 . Front portion  24  is shaped and dimensioned to engage rotatable member  500  of the printing press. Front portion  24  has a slot  28  for receiving the two spaced protuberances  502  of rotatable member  500 . Front portion  26  has a central hole  32  for receiving the central outwardly projecting shaft  504  of rotatable member  500 . Slot  28  has two outwardly opening walls  30  which slope outwardly with respect to longitudinal axis  31  of drive-limiting tool  20 . Rear portion  26  has an axially projecting drive shaft  34 . 
     (c) Providing a power drill  900 . In a preferred embodiment, power drill  900  is reversible. 
     (d) Installing drive shaft  34  of drive-limiting tool  20  in power drill  900 . 
     (e) Engaging rotatable member  500  with front portion  26  of drive-limiting tool  20 . That is, placing the two spaced protuberances  502  in slot  28 , and outwardly projecting shaft  504  into central hole  32 . 
     (f) Activating power drill  900  so that drive-limiting tool  20  rotates rotatable member  500 . 
     (g) Continuing to activate power drill  900  until table  560  reaches one of the uppermost position  570  and lowermost position  580  wherein rotatable member  500  experiences rotational resistance and ceases to rotate. That is, rotating rotatable member  500  until table raising and lowering mechanism  550  reaches its uppermost or lowermost limit. 
     (h) When rotational member  500  ceases to rotate, because of the slope of the walls  30  of slot  28 , walls  30  are urged away from protuberances  502  thereby causing drive-limiting tool  20  to disengage from rotatable member  500 , thereby preventing the table raising and lowering mechanism  550  from being overdriven. In other words, as table raising and lowering mechanism  550  reaches its limit, rotatable member  500  ceases to freely rotate, and because of the slope in the walls  30  of slot  28 , slot  28  rides up protuberances  502  and ultimately disengages drive-limiting tool  20  from rotatable member  500 . In a preferred embodiment of the present invention, walls  30  of slot  28  slope outwardly about 30° from longitudinal axis  31  of drive-limiting tool  20 . This angle provides a useful compromise between (1) a lesser angle which would tend to cause drive-limiting tool  20  to remain in contact with rotatable member  500  too long and therefore risk overdriving table raising and lowering mechanism  550 , and (2) a greater angle which would tend to cause drive-limiting tool  20  to unwantingly slip off of rotatable member  500  during the raising and lowering process. 
     Another very similar method for raising and lowering a feed or delivery table of a printing press includes the steps of (refer also to FIGS. 7-25 as described above); 
     (a) Providing a printing press having rotatable members  700  connected to both its feed and delivery tables  560 , the rotatable member  700  for raising and lowering the respective tables  560 , the rotatable member  700  having a longitudinal axis  703 , three circular holes  702  disposed parallel to longitudinal axis  703 , and a central outwardly projecting shaft  704 , table (feed or delivery)  560  having an uppermost position  570  and an opposite lowermost position  580 , wherein rotatable member  500  can only raise or lower the table  560  between the uppermost  570  and the lowermost  580  positions. That is, as rotatable member  700  is turned the table  560  moves according to the direction of rotation until either the uppermost  570  or lowermost  580  position is reached. At either of these extreme positions, the table raising and lowering mechanism  550  reaches its limit and can move no more, therefore rotatable member  700  experiences rotational resistance and ceases to rotate (i.e. cannot be rotated further). Continued attempts to forcibly rotate rotatable member  700  can overdrive and consequently damage the table&#39;s raising and lowering mechanism  550 . 
     (b) Providing a drive-limiting tool  120 . Drive-limiting tool  120  having a front portion  124 , an opposite rear portion  126 , and a longitudinal axis  131 . Front portion  124  is shaped and dimensioned to engage rotatable member  700  of the printing press. Front portion  124  has three rounded protuberances  128  for engaging the three holes  702  in rotatable member  700 . Front portion  124  has a central hole  132  for receiving the central outwardly projecting shaft  704  of rotatable member  700 . Rear portion  126  has an axially projecting drive shaft  134 . 
     (c) Providing a power drill  900 . In a preferred embodiment, power drill  900  is reversible. 
     (d) Installing drive shaft  134  of drive-limiting tool  120  in power drill  900 . 
     (e) Engaging rotatable member  700  with front portion  124  of drive-limiting tool  120 . That is, placing the three rounded protuberances  128  in the three holes  702 , and outwardly projecting shaft  704  into central hole  132 . 
     (f) Activating power drill  900  so that drive-limiting tool  120  rotates rotatable member  700 . 
     (g) Continuing to activate power drill  900  until table  560  reaches one of the uppermost position  570  and lowermost position  580  wherein rotatable member  700  experiences rotational resistance and ceases to rotate. That is, rotating rotatable member  700  until table raising and lowering mechanism  550  reaches its uppermost or lowermost limit. 
     (h) When rotatable member  700  ceases to rotate, because of the three rounded protuberances  128 , the three rounded protuberances  128  are urged out of the three holes  702  thereby causing drive-limiting tool  120  to disengage from rotatable member  700 , thereby preventing table raising and lowering mechanism  550  from being overdriven. In other words, as table raising and lowering mechanism  550  reaches its limit, rotatable member  700  ceases to freely rotate, three rounded protuberances ride up and out of three holes  702  and ultimately disengage drive-limiting tool  120  from rotatable member  700 . In a preferred embodiment of the present invention, three rounded protuberances  128  are substantially dome-shaped. 
     Testing Results—The present invention has been extensively tested, has surpassed all expectations. Hand cranks are no longer necessary for raising or lowering the feed or delivery tables. Where it used to take approximately 30 seconds to lower the feed table cranking the hand crank as fast as possible, it now takes less than 5 seconds and requires virtually no effort. The drive-limiting tool of the present invention has completely eliminated the most wearisome task associated with the operation of small offset printing presses. It has also increased production, reduced downtime, safeguards printing press operators physical well being and boosts a printing press operator&#39;s moral. 
     The preferred embodiments of the invention described herein are exemplary and numerous modifications, dimensional variations, and rearrangements can be readily envisioned to achieve an equivalent result, all of which are intended to be embraced within the scope of the appended claims.