Patent Publication Number: US-7216564-B2

Title: Machinery slot cover

Description:
This application is a divisional application of U.S. application Ser. No. 09/548,706 which was filed on Apr. 13, 2000 now U.S. Pat. No. 6,786,110 which application claims priority on U.S. Provisional Application Ser. No. 60/129,587 filed Apr. 16, 1999 the disclosures of which are incorporated herein by reference. 

   FIELD OF THE INVENTION 
   The present invention relates to improvements in machinery slot covers that are used in a variety of applications including but not limited to fork lifts, medical diagnostic equipment and other applications having an arm travels along an opening or slot in a column or tube. 
   BACKGROUND OF THE INVENTION 
   Arms moving along an opening or slot in a column or tubular member are common in a number of industrial applications. One well known example of such arms is found on a fork lift truck. Another example is found in medical diagnostic devices such as some scanning equipment. In these scanning devices, for example, a patient lies on a bed and a diagnostic device on an arm travels along a path to scan the patient. Other applications include the field of robotics where a moving arm may be performing a task and travel in a slot in the device. In many of these applications there is a load bearing arm that travels along a slot or opening in a column. The arm rides on a carriage over one or more tracks or other means in the column. 
   One of the problems encountered in, for example, fork lift applications is the problem of dirt and debris entering the slot in the column where the arm travels ultimately causing problems in the operation of the fork lift. Fork lifts are frequently used in a warehouses or storage buildings which have a significant amount of debris and dirt present. In addition, significant amounts of dust can be generate in the working environments of these devices. These deleterious materials have a tendency to enter the slot in the column and cling to the interior of the column, thus creating undue wear on the moving parts and other problems in the operation of the arm. This problem is particularly acute where you have lubricants present on open surfaces in the interior of the column to facilitate movement of the arm in the slot. These lubricants have a tendency for attracting any dirt or debris which becomes attached to the lubricated parts due to the adhesive nature of the lubricants. This dust and debris can increase wear of critical moving parts. 
   Fork lifts, in many applications are also used outside where the arm and the slot are subjected to the environment, particularly moisture. In these situations the slot provides an entrance way for moisture that can cause oxidation of critical parts and reduce the useful life span of the equipment. In medical applications, besides the issue of undesirable material entering into the slot there is also the problem that the interior of the column can not be readily cleaned and disinfected. These recesses will provide a resting place for the dirt and debris that is often inaccessible. This dirt and debris will have a tendency to harbor germs that may spread throughout the facility. Similarly, in many applications where robotic arms are used there are similar issues with undesirable material entering into the slot in which the carriage travels. 
   In addition to these problems, there is also a major safety issue for equipment having a carriage or other mechanism traveling in a slot in a column. The unprotected opening can attract fingers and hands that could be injured if the machine is in operation while the hands are present. Many times significant forces can develop as an arm or other device travels in the slot that could crush or sever fingers caught in the slot. 
   One approach to solve the problem of the open slot in a column has been to provide a brush member that is attached on one side of the slot and has its bristles extend over the slot toward the other side of the slot. Alternatively, there may be a pair of brush members that are attached to each edge of the slot with their bristles extending toward the center of the slot. The brush members use the bristles of the brush as a means to block the opening and prevent foreign material from entering the slot. The brush bristles are sufficiently flexible to permit the arm mechanism to travel along the slot. The problem with the use of a brush is that the individual bristles give the illusion of sealing the opening but in reality do not. Fingers and hands can still be injured during use because the opening is still at least partially opened to the exterior. With respect to debris and foreign matter entering the slot, the fingers create a problem in that there are considerable numbers of individual bristles. Each of these bristles provides a surface for dirt and grime to rest and can create a health hazard in those applications where a clean surface is required. 
   It is an object of the present invention to provide a cover that effectively seals the opening of a slot in a column having a moving arm. 
   It is an object of the present invention to provide a cover that permits an arm to travel in a slot in a column without permitting dirt and debris to enter the slot. 
   It is an object of the invention to provide a cover for an opened slot containing a moving member that travels along the slot that provides protection to workers and prevents hands, and fingers, clothing tools and equipment from becoming caught in the slot. 
   It is an object of the invention to provide an improved fork lift having a mechanism that travels in a slot that is protected from the environment. 
   It is an object of the invention to provide an improved medical diagnostic device having arm that travels in a slot that is protected from the environment. 
   It is an object of the invention to provide a robotic arm that travels along a slot in a tubular member without permitting dirt and debris to enter the slot. 
   SUMMARY OF THE INVENTION 
   The present invention is directed to improvements in machinery slot covering mechanism that are used in a variety of applications including but not limited to fork lifts, medical diagnostic equipment and other applications having an arm travels along an opening or slot in a column or tube. According to the present invention there is an improved cover for a mechanism having an open slot along which a member travels. 
   A fork lift truck has a fork that travels from lowered position to pick up a load to a carrying position where the fork is raised to a suitable height. The lift assembly in a fork lift truck typically includes one or a plurality of forwardly extending fork prongs. The fork prongs are attached to carriage by an accessory mounting means. The accessory mounting means may be used for attaching the prongs or any other suitable article that can be moved by the carriage as it moves. 
   A mast houses a carriage that raises and lowers the accessory mounting means. The mast can be, for example, a generally tubular member or column having a pair of sidewalls that join a rear wall to a front wall. The front wall typically has an opening or slot that is frequently in the form of a narrow rectangle although other shapes are possible. The front wall forms a top member and a bottom member which are joined together by a pair of side members. The side members form the sides of the opening or slot and the top member and the bottom member form the top and bottom respectively. The length and design of the slot coupled with the size of the carriage and the mast determines the path of travel of the carriage within the mast. Extending from the first member toward the second side member is a first connection means. Extending from the second side member toward the first side member is second connection means. Joining the first and second connection means is slot cover. 
   The connection means each may have a securing surface for securing the connection means to the side member. The connection means has at least one connecting member that mates with a receiving member on the slot cover. Alternatively, the slot cover may have the connecting member that mates with a receiving member on the connection means. In a preferred embodiment of the invention the connection means has a three connecting members. The three connecting members are separated by receiving members. Similarly, the slot cover is provided with three connecting members in a preferred embodiment. The connecting members in the slot cover are also separated by receiving members. 
   As the carriage moves along the slot, the cover guide which is connected to the carriage also moves in the same direction as the carriage. The cover guide is generally a plate-like member being generally rectangular in configuration, although any suitable shape is possible. Support wings are on either side of the cover guide and provide a surface for connecting the accessory mount means to the cover guide. The cover guide is preferably designed so that the cover guide has a recessed portion in which the cover passes during movement of the carriage. As the cover guide moves along its path, the cover guide lifts the cover and causes the mated connecting members in the direction of travel to become separated from their respective receiving members. As the cover guide travels along the slot, the raised portion of the slot cover is pressed into engagement with the connection means by a pressure bar. The slot cover prevents ingress of debris and moisture into the mast thus eliminating the problem of the prior art designs. In addition, the slot cover prevents injury to hands and fingers due to the movement of the carriage in the slot. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  shows a representative fork lift employing the cover assembly of the present invention with the forks in a lowered position. 
       FIG. 2  shows a representative fork lift employing the cover assembly of the present invention with the forks in a lowered position. 
       FIG. 3  shows a portion of the cover assembly of the present invention. 
       FIG. 4  shows a side cutaway view of the cover assembly of the present invention. 
       FIG. 5  shows the cover assembly of the present invention with the cover engaged. 
       FIG. 6  shows the cover assembly of the present invention with the cover disengaged. 
       FIG. 7  shows an alternative arrangement of the cover assembly of the present invention with the cover engaged. 
       FIG. 8  shows the side profile of a connecting member and a receiving member of the present invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   The present invention relates to improvements in machinery slot covers that are used in a variety of applications including but not limited to fork lifts, medical diagnostic equipment and other applications having an arm travels along an opening or slot in a column or tube. The present invention has particular application in the field of fork lift trucks. As shown in  FIG. 1  there is a representative fork lift truck  10  that has its fork  11  in its forward lowered position to pick up a load. The invention may also be used on other types of forklift trucks besides the type shown in  FIG. 1  and the invention is not intended to be limited by the type fork lifts or other equipment it is being used.  FIG. 2  shows the fork retracted to a carrying position and raised to a suitable height. The fork lift truck includes a generally U-shaped frame  12  having a pair of driven wheels  13  on the front and a caster wheel  14  on the back. The two legs of the U-shaped frame extending forwardly are aligned generally parallel to each other to support the mast  15  and carriage  16  as it is reciprocated forwardly and backwardly by for example a piston and cylinder combination  17 . A seat is mounted on the frame usually near the caster wheel  14  and the various components for steering the fork lift and providing elevational control are mounted in proximity to the seat. The lift assembly includes one or a plurality of forwardly extending fork prongs  18 . The fork prongs are attached to carriage  16  by means of an accessory mounting means  19 . The accessory mounting means  19  may be used to attach the prongs or any other suitable article that can be moved by the carriage  16  as it travels. 
   The mast  15  which houses the carriage  16  may be, for example, a generally tubular member or column having a pair of sidewalls  20  and  20 A that join rear wall  21  to front wall  22 . The drawing depicts a generally rectangular cross section for the tubular member but this can be any shape as long at the carriage can ride within the tubular member. The mast is shown in connection with a fork lift apparatus in  FIG. 1  but can actually be used in a number of different applications. Front wall  22  of the mast has a pair of side members  23  and  24  that extend from the sidewalls and which define the slot  25 . Slot  25  determines the path of travel of the carriage  16  within the mast. Extending from the first side member  23  toward the second side member  24  is a first connection means  26 . Extending from the second side member  24  toward the first member is second connection means  27 . Joining the first and second connection means is slot cover  28 . 
   The connection means  26  and  27  each may have a securing surface  29  for securing the connection means to the side member. The connection means has at least one connecting member  30  that mates with receiving member  38  on the slot cover  28 . Alternatively, the slot cover may have the connecting member that mates with a receiving member on the connection means. In a preferred embodiment of the invention the connection means has a three connecting members  30 ,  32  and  33 . The three connecting members  30 ,  32  and  33  are separated by receiving members  34  and  35 . Similarly, the slot cover is provided with three connecting members  31 ,  36  and  37 . The connecting members  31 ,  36  and  37  are separated by receiving members  38  and  39 . The connection means may be a separate member from the flange or it may be an integral part thereof as depicted in  FIG. 7 . 
   As shown in  FIG. 3  as the carriage rises and falls in the slot the cover guide  40  which is connected to the carriage also rises and falls. The cover guide is generally a plate like member being generally rectangular in configuration. Support wings  41  and  42  are on either side of the cover guide and provide a surface for connecting the accessory mount means  19  to the cover guide  40 . The cover guide is preferably designed so that the cover guide has a recessed portion  43  in which the cover passes during movement of the carriage. As the cover guide moves along its path, the cover guide lifts the cover and causes the mated connecting members  31 ,  36  and  37  to become separated from receiving members  34  and  35 . Similarly, the mated connecting members  30 ,  32  and  33  are also caused to become separated from receiving members  38  and  39 . As the cover guide travels downwardly along the slot, the raised portion of the slot cover is pressed into engagement with the connection means by the pressure bar  44 B. Similarly, as the cover guide travels upwardly along the slot, the raised portion of the slot cover is pressed into engagement with the connection means by the pressure bar  44 A. As can be seen from  FIG. 3  the slot cover prevents ingress of debris and moisture into the mast thus eliminating the problem of the prior art designs. In addition, the slot cover prevents injury to hands and fingers due to the movement of the carriage in the slot. 
     FIG. 4  shows the side view of the arrangement of the carriage  16 , cover guide  40  and the accessory mount  19  in the present invention. The carriage  16  is connected to the cover guide by any suitable means. In one embodiment the carriage and cover guide may be a single member. The cover guide is connected to the accessory mount  19 . The pressure bars  44 A and  44 B are retained in position by springs  45  and  46 . Preferably the springs are adjustable and/or replaceable to provide the necessary force to reconnect the slot cover as the carriage makes its travels. The assembly may be further protected by a cover  47 . 
   The slot cover is preferably made of a flexible plastic material as are the connection means. Preferably the connecting members  30 – 33  and  36 – 37  are provided with a cross section that mates with the shape of the receiving members  34 , 35 ,  38  and  39 . In a preferred embodiment the connecting members have sides  48  and  49  a base  50  and a top surface  51 . Preferably, the side  48  is generally concave and side  49  is generally straight or convex giving the connecting member a stocking like profile. The receiving members are also preferably a similar configuration. Specifically, the receiving member has sides  52  and  53  a base  54 . Preferably, the side  52  is generally concave and side  53  is generally straight or convex giving the receiving member and the connecting member a stocking like profile. Alternatively, the receiving members may have a different profile provided that they mate together to provide a proper fit to secure the slot cover to the connection means. Although the present invention has particular advantages when used with fork lifts it also has applicability when used in other applications such as in the field of medical diagnostics where the accessory mount  19  has for example a medical diagnostic device such as a scanner connected thereto such that the diagnostic device travels along a slot that is provided with a slot cover in accordance with the present invention.