Abstract:
The boat seat has a seat back and seat base connected by a pivot. The pivot has a back arm, a base arm and a middle arm connected between the back and base arms. The pivot utilizes several implementations including but not limited to, a lock pin embodiment, a latch embodiment, a single lock bar embodiment, a single gear embodiment and a double gear embodiment. The pivot enables the seat, without any initial limiting position and in virtually any direction and in any order, to be tilted and locked into multiple positions including but not limited to, a vertical position supporting a fully seated person, a horizontal position supporting a semi standing person or providing the front surface of seat back as a shelf, or a folded position for convenient storage and transport.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to an adjustable boat seat. 
     2. Background Art 
     Fishing boats may include a seat which supports a person who is substantially standing, and another seat which allows a person to be fully seated. If a person gets tired of sitting or standing and he wants to change from one position into another, he must either walk on the boat from one chair to another, or remove one type of seat and install another type. In either case, the procedure may be time consuming and dangerous, because a person may slip off while walking between the chairs, or the person may trip over the seat not in use at the time. Therefore, there is a need for a boat seat arrangement that can provide both the functions more efficiently and conveniently. 
     SUMMARY OF THE INVENTION 
     The present invention combines the functions of the two chairs into a single chair arrangement. In addition, the present invention also has a function to use the front surface of the seat back as a shelf when the seat back is in a horizontal position. Further, the present invention also has the ability to fold down for convenient storage and transport. The seat may be optionally mounted on a boat. 
     An object of the invention is to provide for a seat that has multiple functions. The seat has basically two cushions: the upper seat back and lower seat base that are connected by a pair of pivotable support arms. The seat back has a front surface, an upper and a lower edge. The boat seat may tilt without any initial limiting position and in virtually any direction and in any order. Further, both the seat back and base may tilt relatively to each other so that a person may be fully seated or be substantially standing against the seat back. Additionally, the seat may also pivot so as to make it possible to convert the boat seat into a shelf by titling the seat back into horizontal position. An additional object of the invention is to make it possible to fold the seat back and base towards each other closely so that the seat may be conveniently transported and stored. 
     The boat seat through a pivot arm mechanism can be manipulated to a semi folded position, where the seat back provides a high top support for a user who is substantially standing against it. Located substantially at the center position on the edge of the lower end, the lower edge has an extending forward center portion between which a user may lay upper thighs to enhance the stability of a semi standing position. The seat can be arranged to have the upper cushion, namely the seat back, be substantially vertical whereby a user may be fully seated. The seat can also be arranged to have the seat back be substantially horizontal whereby providing as a shelf on the front surface of the seat back. The seat can also be completely folded down by rotating the upper and lower cushions towards each other whereby the seat can be conveniently transported and stored. A number of pivotable support arm mechanisms may be used as long as such mechanisms rotate and lock the pivotal cushions in different angles including from a vertical to a horizontal position and vise versa. 
     In one implementation, the pivot arm mechanism comprises a first back arm, a first middle arm and a first base arm where the first back arm is pivotably connected through a screw or rivet to one end portion of the first middle arm which is in turn pivotably connected at its other end portion through another screw or rivet to a head portion of the first base arm. 
     The first back arm has two substantially parallel plates connected along a small peripheral edge whereby forming a substantially equal distance space in which a first end portion of the first middle arm may be inserted. One plate of the first back arm is longer than the other, whereas the longer plate provides an extension area for fastening a seat back cushion, while the shorter plate is substantially round shaped having at least two recessed portions on its round edge. Obviously, the more apart the two end recessed portions are, the bigger the angular degree will be, therefore, the closer the seat back and seat base may be folded. There are a first and a second openings through both the longer and shorter plates respectively along the same axis and are located at the geometrical center of the shorter plate. 
     In a first alternative implementation for the first back arm, the first alternative back arm is formed in a one-piece material separated by and bent along three parallel separation lines. It forms two substantially parallel plates connected along a small peripheral edge whereby forming a substantially equal distance space in which a first end portion of the first middle arm may be inserted. One plate of the first back arm is longer than the other and the longer plate bends 90 degrees to provide an extension area for fastening a seat back cushion, while the shorter plate is substantially round shaped having at least two recessed portions on its round edge. Obviously, the more apart the two end recessed portions are, the bigger the angular degree will be, therefore, the closer the seat back and seat base may be folded. There are a first and a second openings through both the longer and shorter plates respectively along the same axis and are located at the geometrical center of the shorter plate. The longer plate has a semicircular slot geometrically centered at the first opening with a recessed portion towards each end corresponding to and paired the recessed portions on the short plate. 
     The first base arm is an L-shaped plate with top portion being substantially round shaped with a first opening at the geometrical center of the round portion and having at least two recessed portions on the round portion edge. Obviously, the more apart the two end recessed portions are, the bigger the angular degree will be, therefore, the closer the seat back and seat base may be folded. The base portion of the first base arm provides an extension area for fastening the seat base cushion. A tilt-and-lock mechanism resides basically on the first middle arm. 
     In a first alternative implementation for the first base arm, the first alternative base arm is formed in a one-piece material separated by and bent along three separation lines, two of which are parallel and perpendicular to the third separation line. It has two identical parallel plates connected on one side whereby forming a substantially equal distance space in which a second end portion of the first middle arm may be inserted. One of the parallel plates has an extended area bent 90 degrees thus providing an extension for fastening the seat base. This alternative first base arm is L-shaped with both top portions of the parallel plates being substantially round shaped with a pair of first openings at the geometrical center of the round portions and having at least two pairs of recessed portions on the round portion edges with each recessed portion of the pair being located at the same location. 
     In the first implementation, the first middle arm is a long plate having a slot on each end portion and, on same side surface, having one lock pin next to each slot but on the inner side towards the center of the long plate, both lock pins protruding only on the same side surface of the first middle arm. Through the first and second openings on the first back arm and the first slot on the first middle arm, the first back arm and first middle arm are engaged by a mounting screw or rivet through which the first middle arm may freely rotate and slide along the first slot. Similarly, through a second slot on the first middle arm and the first opening on the first base arm, the first middle arm and first base arm are engaged by a mounting screw or rivet through which the first base arm may freely rotate and slide along the second slot. This lock pin type pivot arm mechanism allows the first back arm and first base arm be tilted, without any initial limiting position and in virtually any direction and in any order, and be locked into any position where the recesses are located by moving the lock pins into corresponding recessed portions on the first back arm and first base arm respectively. 
     In a first alternative implementation for the lock pin type pivot arm mechanism, a first and second locking coil springs are attached between the first mounting screw (or rivet) and first lock pin and between the second mounting screw (or rivet) and second lock pin whereby holding the lock pins in place. 
     In a second alternative implementation of the lock pin type pivot arm mechanism, a single locking coil spring is attached between the first mounting screw (or rivet) and the second mounting screw (or rivet) whereby holding the lock pins in place. 
     In a first alternative implementation for the first middle arm, the first alternative middle arm is identical to the above mentioned first middle arm except that there is a piece of elastic material affixed onto the first middle arm across each sliding slot to keep mounting screw or rivet from sliding inside the slot thus keeping the lock pin in place. 
     In yet another second alternative implementation for the first middle arm, the second alternative first middle arm is identical to the above mentioned first alternative first middle arm except that both the lock pins are protruding on both side surfaces of the first middle arm. 
     In another implementation, the seat uses the identical first back arm and a first base arm as in the first implementation but with a different middle arm, namely, a second middle arm. In this alternative embodiment, the second middle arm is a long plate having an opening near each end portion. Through the first openings on the first back arm and a first opening on the second middle arm, the first back arm and second middle arm are engaged by a mounting screw through which the second middle arm may freely rotate. Similarly, through a second opening on the second middle arm and the first opening on the first base arm, the second middle arm and the first base arm are engaged by a mounting screw through which the first base arm may freely rotate. 
     On one side surface of the second middle arm, a first L-shaped latch is mounted at its first end by a mounting screw onto the second middle arm near the first opening of the second middle arm such that the first L-shaped latch may pivotably rotate and being able to latch upwardly into one of the recesses on the first back arm. A rotating lever is mounted substantially at its middle section by a mounting screw onto the center position of the second middle arm such that the rotating lever may pivotably rotate. On the same side surface, a second L-shaped latch is mounted at its first end by a mounting screw onto the second middle arm near the second opening of the second middle arm such that the second L-shaped latch may pivotably rotate and being able to latch downwardly into one of the recesses on the first base arm. A first upper coupling bracket is connected by bolts between a first end portion of the rotating lever and near the notch position of the first latch. Similarly, a first lower coupling bracket is connected by bolts between a second end portion of the rotating lever and near the notch position of the second latch. The first and second latches, the rotating lever and the first upper and first lower coupling brackets form a latch type rotate-and-lock device whereby the first and second latches may lock or release, upwardly and downwardly, into the recesses on the first back arm and first base arm respectively, when a clock wise or counter clock wise force is applied pivotably, depending upon the initial position when the rotating lever is connected with the coupling brackets. Optionally, a handle connected to the rotating lever may be added to help user to use the latch type tilt-and-lock device more easily. 
     In yet another implementation, the seat uses the identical first back arm and first base arm as in the first implementation but with a different middle arm, namely, a third middle arm. In this alternative embodiment, the third middle arm is a long plate having a slot near each end portion and, having one straight lock bar placed on the center position of the third middle arm extending next to each slot and along the axis connecting the two slots. Through the first and second openings on the first back arm and the first slot on the third middle arm, the first back arm and third middle arm are engaged by a mounting screw through which the third middle arm may freely rotate and slide along the first slot. Similarly, through a second slot on the third middle arm and the first opening on the first base arm, the third middle arm and first base arm are engaged by a mounting screw through which the first base arm may freely rotate and slide along the second slot. This single lock bar type pivot arm mechanism allows the first back arm and first base arm be tilted, without any initial limiting position and in virtually any direction and in any order, and be locked into any position where the recesses are located by moving the single lock bar into corresponding recessed portions on the first back arm and first base arm respectively. 
     In yet another implementation, a second back arm and a second base arm are essentially the same as those used in the above mentioned implementations, except that in this implementation, the second back arm and second base arm have multiple recessed portions to receive a gear mechanism. In this implementation, a fourth middle arm is a long plate having an opening near each end portion, and having a first round gear placed on the center position of the fourth middle arm. The first gear has a handle bar perpendicularly connected at the center position of the first gear for ease of operation. The first gear is connected to the fourth middle arm through an extendable pin mechanism so that the first gear may be pulled or pushed perpendicularly, outwardly or inwardly to disengage or engage the single gear lock mechanism respectively. There are multiple receiving cavities on the first gear surrounding its center along an equal radius line to receive a third lock pin which is connected to the fourth middle arm along the same radius line and on the same side surface where the first gear is placed. Through the first and second openings on the second back arm and the first opening on the fourth middle arm, the second back arm and fourth middle arm are engaged by a mounting screw through which the fourth middle arm may freely rotate. Similarly, through a second opening on the fourth middle arm and the first opening on the second base arm, the fourth middle arm and second base arm are engaged by a mounting screw through which the second base arm may freely rotate. When the first gear is pulled out and disengaged, this single gear pivot arm mechanism allows the second back arm and second base arm be tilted without any initial limiting position and in virtually any direction and in any order and, be locked into any position where the recesses are located by engaging the first gear inwardly and placing the third lock pin into one of the receiving cavities on the first gear. 
     In yet another implementation, a third back arm and a third base arm are the same as those used in the above mentioned single gear implementation except that the spacing of the multiple recesses may be different due to different gear diameters. In this implementation, a fifth middle arm is a long plate having an opening near each end portion and, having a second and third round gear engaged with each other and placed on the fifth middle arm such that the second and third gears may engage with the multiple recesses on the third back and third base arms respectively. Through the first and second openings on the third back arm and the first opening on the fifth middle arm, the third back arm and fifth middle arm are engaged by a mounting screw through which the fifth middle arm may freely rotate. Similarly, through a second opening on the fifth middle arm and the first opening on the third base arm, the fifth middle arm and third base arm are engaged by a mounting screw through which the third base arm may freely rotate. The second gear has a handle bar perpendicularly connected at the center position of second gear for ease of operation. The second gear is connected to the fifth middle arm through an extendable pin mechanism so that the second gear may be pulled or pushed perpendicularly, outwardly or inwardly to disengage or engage the double gear lock mechanism respectively. There are multiple receiving cavities on the second gear surrounding its center along an equal radius line to receive a fourth lock pin which is connected to the fifth middle arm along the same radius line and on the same side surface where the second gear is placed. When the second gear is pulled out and disengaged, this double gear pivot arm mechanism allows the third back arm and third base arm be tilted without any initial limiting position and in virtually any direction and in any order and, be locked into any position where the recesses are located by engaging the second gear inwardly and placing the fourth lock pin into one of the receiving cavities on the second gear. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above mentioned and other features and objects of this invention, and the manner of attaining them, will become more apparent and the invention itself will be better understood by reference to the following description of embodiments of the invention taken in conjunction with e accompanying drawings, wherein: 
     FIG. 1 is a perspective view of a first embodiment of the invention with the lock pin type pivot arm mechanism. 
     FIG. 2 is a perspective view of the embodiment of FIG. 1 with the seat back in a vertical position for a fully seated position. 
     FIG. 3 is a perspective view of the embodiment of FIG. 1 with the seat back in a substantially horizontal position and locked into place whereby the user may rest against the top cushion while remaining substantially standing. 
     FIG. 4 is a perspective view of the embodiment of FIG. 1 with the seat back being fully folded towards the seat base whereby the seat may be conveniently transported and stored. 
     FIG. 5 is a schematic view of the first alternative implementation of the first back arm, namely, the one-piece material implementation. 
     FIG. 5 a  is a perspective view, from top, front, inside and other angles, of the first alternative implementation of the first back arm. 
     FIG. 6 is a schematic view of the first alternative implementation of the first base arm, namely, the one-piece material implementation. 
     FIG. 6 a  is a perspective view, from top, back, front and other angles, of the first alternative implementation of the first base arm. 
     FIG. 7 is a perspective view of the first alternative implementation for the lock pin type pivot arm mechanism, namely, with the double locking coil springs. 
     FIG. 8 is a perspective view of the second alternative implementation of the lock pin type pivot arm mechanism, namely, with a single locking coil spring. 
     FIG. 9 is a perspective view of the first alternative implementation of the first middle arm, namely, with double elastic locking materials affixed across the sliding slot to keep lock pins in place. 
     FIG. 10 is a second alternative implementation for the first middle arm, namely, with both locking pins protruding on both side surfaces of the first middle arm with the double elastic locking materials. 
     FIG. 11 is an inside view of the lock pin type pivot arm mechanism with the first alternative implementations for both first back and first base arms when the seat back is in a vertical position. 
     FIG. 12 is an angled view of the lock pin type pivot arm mechanism with the first alternative implementations for both first back and first base arms when the seat back is in a vertical position. 
     FIG. 13 is an angled view of the lock pin type pivot arm mechanism with the first alternative implementations for both first back and first base arms when the seat back is in a substantially horizontal position. 
     FIG. 14 is an angled view of the lock pin type pivot arm mechanism with the first alternative implementations for both first back and first base arms when the seat back is in a substantially folded position. 
     FIG. 15 is a perspective view of the latch type pivot arm mechanism. 
     FIG. 16 is a perspective view of the embodiment of FIG. 15 with the seat back in a vertical position for a fully seated position. 
     FIG. 17 is a perspective view of the embodiment of FIG. 15 with the seat back in a substantially horizontal position and locked into place whereby the user may rest against the top cushion while remaining substantially standing. 
     FIG. 18 is a perspective view of the embodiment of FIG. 15 with the seat back being fully folded towards the seat base whereby the seat may be conveniently transported and stored. 
     FIG. 19 is a perspective view of the pivot arm mechanism of a third embodiment using a single lock bar mechanism. 
     FIG. 20 is a perspective view of the pivot arm mechanism of a fourth embodiment using a single gear mechanism. 
     FIG. 21 is a perspective view of the pivot arm mechanism of a fifth embodiment using a double gear mechanism. 
     Corresponding reference characters indicate corresponding parts throughout the several views. Although the drawings represent embodiments of the present invention, the drawings are not necessarily to scale and certain features may be exaggerated in order to better illustrate and explain the present invention. The exemplification set out herein illustrates embodiments of the invention, in several forms, and such exemplifications are not to be construed as limiting the scope of the invention in any manner. 
    
    
     DESCRIPTION OF THE INVENTION 
     The embodiments disclosed below are not intended to be exhaustive or limit the invention to the precise forms disclosed in the following detailed description. Rather, the embodiments are chosen and described so that others skilled in the art may utilize their teachings. 
     Referring to the drawings in greater detail, the seat of the present invention essentially consists of an upper cushion seat back  500  with a front surface  503 , an upper edge  501  and a lower edge  502 , a lower cushion seat base  100 , a pivot arm mechanism  10  for one implementation,  101  for an alternative implementation,  102 ,  103  and  104  for more alternative implementations. Since seats with a base and a back which can tilt relatively are well known in the prior art, only that which relates directly or indirectly to the invention will be described in what follows. The person skilled in the art in question will draw from the current conventional solutions at his disposal in order to deal with the particular problems with which he is confronted. 
     In what follows, an equivalent element will be generally designated by an identical reference numeral in each distinct embodiment. 
     As can be seen with reference to all drawings, a seat with back cushion  500  and base cushion  100  according to the invention is provided with pivot arm mechanism to serve as a tilt-and-lock device. Note that base cushion  100  may be optionally mounted on a boat floor. As result of this device, for example of the type given in all the above mentioned embodiments, it is possible to tilt back cushion  500  relative to seat base cushion  100 , without any initial limiting position and in any direction or any order and, in a range larger than 90 degrees between a virtually vertical upright position and other tilted positions which can be altered as desired with the most useful positions being the vertical, horizontal and completely folded. 
     Except for seat back  500 , since seat base  100  is of any appropriate conventional type, it has only been illustrated in outline form for clarity of depiction. Back cushion  500  and base cushion  100  are intended to be carried by pivotable support arms  10  in the first embodiment or  101  in the second embodiment, or  102 ,  103  and  104  in more alternative embodiments. In all embodiments, pivotable support arm comprises a back arm, intended to fasten to back cushion  500 , and base arm, intended to fasten to base cushion  100 , and a middle arm, pivotably connected between back arm and base arm, having features which form a tilt-and-lock mechanism. 
     In one implementation as shown in FIGS. 1 through 4, the pivot arm mechanism uses first back arm  20  having two substantially parallel plates  20   a  and  20   b  connected along peripheral edge  20   c  thereby forming a substantially equal distance space in which first end portion  31  of first middle arm  30  may be inserted. One plate  20   a  of first back arm  20  is longer than other  20   b  whereas longer plate  20   a  provides an extension area for fastening seat back cushion  500 , while shorter plate  20   b  is substantially round shaped having at least two recessed portions, namely first recess  22  and second recess  24  on its round edge. Obviously, the more apart the two end recessed portions  22  and  24  are, the bigger the angular degree will be, therefore, the closer the seat back  500  and seat base  100  may be folded. Same is also true, namely, the more recessed portions, the more adjustable seat positions. There are a first opening  28  and a second opening  29  on both longer and shorter plates  20   a  and  20   b  respectively, along the same axis which are located at the geometrical center of shorter plate  20   b.    
     First middle arm  30  comprises a long plate having first end portion  31  and second end portion  33 , first slot  32  and second slot  34  on each end portion respectively, and first lock pin  36  and second lock pin  38  respectively next to each slot but on the inner side towards the center of first middle arm  30 . Both lock pins  36  and  38  protrude outwardly on the same side surface of first middle arm  30 . Through first and second openings  28  and  29  on first back arm  20  and first slot  32  on first middle arm  30 , first back arm  20  and first middle arm  30  are engaged by first mounting screw  51  with first nut  50  through which first middle arm  30  may freely rotate and slide along first slot  32 . Peripheral connection edge  20   c  between parallel plates  20   a  and  20   b  on first back arm  20  is to provide minimal space constraint whereby first middle arm  30  partially inserted and engaged between parallel plates  20   a  and  20   b  on first back arm  20  may pivotably rotate along first mounting screw  51  and slide along first slot  32  to a significant degree. First back arm  20  and first middle arm  30  may be locked into different positions by positioning first lock pin  36  into one of recessed portions  22  or  24  on shorter plate  20   a  of first back arm  20 . 
     Connected to the other end portion of first middle arm  30  is L-shaped first base arm  40  with top round portion  41  being substantially round shaped with first opening  48  at the geometrical center of top round portion  41  and having at least two recessed portions, namely, first recess  42  and second recess  44  on the edge of top round portion  41 . Obviously, the more apart the two end recessed portions  42  and  44  are, the bigger the angular degree will be, therefore, the closer the seat back  500  and seat base  100  may be folded. Same is true that the more recessed portions, the more seat positions. Through second slot  34  on first middle arm  30  and first opening  48  on first base arm  40 , first middle arm  30  and first base arm  40  are engaged by second mounting screw  53  with second nut  52  through which first base arm  40  may freely rotate and slide along second slot  34 . First middle arm  30  and first base arm  40  may be locked into different positions by positioning second lock pin  38  into one of recessed portions  42  or  44  on the round shaped edge of top round portion  41  of first base arm  40 . Base portion  43  of first base arm  40  provides an extension area for fastening seat base cushion  100 . 
     In a first alternative implementation for the first back arm  20 , the first alternative back arm  220  as shown in FIG. 5 and 5 a , is formed in a one-piece material consisting of four sections  220 A,  220 B,  220 C and  220 D, separated by and bent along three parallel separation lines. First section  220 D is rectangularly shaped and has three holes  226  through which the seat back may be attached by mounting screws or rivets. Second section  220 A is wedge shaped with two parallel sides and the longer side is connected with first section  220 D and the shorter side is connected with a rectangularly shaped third section  220 C. The end portion of wedge shaped second section  220 A has one hole  229  and a semicircular slot  225  centered geometrically along hole  229 . Semicircular slot  225  points towards the wedge tip direction and it has two recessed portions  222 A and  224 A towards opposite ends and the tip of wedge shaped second section  220 A points away from hole  229  and semicircular slot  225 . The fourth section  220 B is sectorially shaped and has a hole  228  at the geometrical center of its semicircular side and the semicircular side has two recessed portions  222 A and  224 B. One straight side of sectorially shaped fourth section  220 B is connected with third section  220 C and the semicircular side points generally the same direction of the wedge tip on second section  220 A. The hole  228 , semicircular side, two recessed portions  222 B and  224 B on fourth section  220 B correspond to and are paired with hole  229 , semicircular slot  225  and two recessed portions  222 A and  224 A on wedged shaped second section  220 A when second section  220 A and fourth section  220 B are folded each 90 degrees towards each other along third section  220 C, therefore, forming a substantially equal distance space in which a first end portion  31  of the first middle arm  30  may be inserted. First section  220 D bends 90 degrees against second section  220 A thus providing an extended area for fastening seat back  500 . FIG. 5 a  is a perspective view showing the first alternative first back arm from different angles. 
     In a first alternative implementation for the first base arm  40 , the first alternative base arm  400  as shown in FIGS. 6 and 6 a , is formed in a one-piece material consisting of four sections  440 A,  440 B,  440 C and  440 D, separated by and bent along three separation lines, two of the separation lines are parallel and perpendicular to the third separation line. First section  449 D is rectangularly shaped and has three holes  446  through which seat base  100  may be attached by mounting screws or rivets. Second section  449 A and fourth section  449 B are identically L-shaped having a base side, a back side and an L-curve side. Second sections  449 A and fourth section  449 B are connected asymmetrically on their back sides by a rectangularly shaped third section  449 C. The base side of L-shaped second section  449 A is connected to first section  449 D. L-shaped second section  449 A and fourth section  449 B have identical round top edges with a hole  448 B and  448 B respectively, at the geometrical centers of their round edges. Both the top edges on second section  449 A and fourth section  449 B have two recessed portions  442 A and  444 A and  442 B and  444 B respectively. Obviously, the more apart the end recessed portions  442 A and  444 A on second section and  442 B and  444 B and fourth section are, the bigger the angular degree will be, therefore, the closer the seat back  500  and seat base  100  may be folded. The holes  448 A and  448 B and two paired recessed portions  442 A and  444 A on second section  449 A and  442 B and  444 B on fourth section  448 B correspond to and are paired with each other when second and fourth sections  449 A and  449 B are folded each 90 degrees towards each other along third section  449 C, thus forming a substantially equal distance space in which a second end portion  33  of said first middle arm  30  may be inserted, first section  449 D bends 90 degrees against second section  449 A whereby providing an extended area for fastening seat base  100 . 
     In a first alternative implementation for the lock pin type pivot arm mechanism as shown in FIG. 7, a first and second locking coil springs  39 A and  39 B (not shown) are attached between the first mounting screw or rivet and first lock pin  36  and between the second mounting screw or rivet and second lock pin  38  (not shown), thus holding the lock pins  36  and  38  in place. 
     In a second alternative implementation for the lock pin type pivot arm mechanism as shown in FIG. 8, a single locking coil spring  39 C is attached between the first mounting screw or rivet and the second mounting screw or rivet, thus holding the lock pins  36  and  38  in place. 
     In a first alternative implementation for the first middle arm  30 , the first alternative middle arm  30 A as shown in FIG. 9, is identical to the first middle arm  30  except that there are two pieces of elastic locking materials  39 A and  39 B affixed onto first middle arm  30 A across each sliding slot  32 A and  34 A respectively, thus keeping mounting screws or rivet from sliding inside the slots  32 A and  34 A whereby holding lock pins  36 A and  38 A in place. 
     In yet anther alternative implementation for the first middle arm  30 , the first alternative middle arm  30 B as shown in FIG. 10, is identical to the above mentioned first middle arm  30  except that both the lock pins  36 B and  38 B are protruding on both side surfaces of the first middle arm  30 B. 
     FIG. 11 through 14 are perspective views for the combined first alternative implementations of both first back and first base arms  200  and  400 . 
     In another implementation as shown in FIGS. 15-18, the pivot arm mechanism uses the same first back arm and first base arm. The first back arm has two substantially parallel plates  20   a  and  20   b  connected along small peripheral edge  20   c  thereby forming a substantially equal distance space in which first end portion  331  of second middle arm  300  may be inserted. Second middle arm  300  has a thickness substantially equal to the space distance between plates  20   a  and  20   b  of first back arm  20 . 
     Second middle arm  300  comprises a long plate having first end portion  331  and second end portion  333 , first opening  332  and second  334  on each end portion respectively. Through first and second openings  28  and  29  on first back arm  20  and first opening  332  on second middle arm  300 , first back arm  20  and second middle arm  300  are engaged by first mounting screw  51  with first nut  50  through which second middle arm  300  may freely rotate. Peripheral connection  20   c  between parallel plates  20   a  and  20   b  on first back arm  20  provides a minimal space constraint such that second middle arm  300  partially inserted and engaged between parallel plates  20   a  and  20   b  on first back arm  20  may pivotably rotate along first mounting screw  51  to a significant degree possible. 
     Connected to the other end portion of second middle arm  300  is the L-shaped first base arm  40 . Through second opening  334  on second middle arm  300  and first opening  48  on first base arm  40 , second middle arm  300  and first base arm  40  are engaged by second mounting screw  53  with second nut  52  through which first base arm  40  may freely rotate. 
     On one side surface of second middle arm  300 , first L-shaped latch  353  is mounted at its first end by third mounting screw  352  onto second middle arm  300  near first opening  332  of second middle arm  300  such that first L-shaped latch  353  may pivotably rotate along third mounting screw  352  and be able to latch upwardly into one of recesses  22  or  24  on the round edge of first back arm  20 . Rotating lever  357  is mounted by fourth mounting screw  358  onto generally the center position of second middle arm  300  such that rotating lever  357  may pivotably rotate along fourth mounting screw  358 . On the same side surface of second middle arm  300  onto which first latch  353  is mounted, second L-shaped latch  361  is mounted at its first end by fifth mounting screw  364  onto second middle arm  300  near second opening  334  of second middle arm  300  such that second L-shaped latch  361  may pivotably rotate along fifth mounting screw  364  and be able to latch downwardly into one of recesses  42  or  44  on the round edge of first base arm  40 . First upper coupling bracket  355  is connected between a first end portion of rotating lever  357  and near the notch position of first latch  353  by first bolt  356  and second bolt  354 , respectively. Similarly, first lower coupling bracket  359  is connected between a second end portion of rotating lever  357  and near the notch position of second latch  361  by third bolt  360  and fourth bolt  362 , respectively. First and second latches  353  and  361 , rotating lever  357  and first upper and first lower coupling brackets  355  and  359  form a latch rotate-and-lock mechanism whereby first and second latches  353  and  361  may lock or release, upwardly and downwardly, into or out of recesses  22  or  24  and  42  or  44  on first back arm  20  and first base arm  40  respectively, when a clock wise or counter clock wise force is applied pivotably, depending upon the initial position when the rotating lever was connected to the coupling brackets. 
     In yet another implementation as shown in FIG. 19, the seat uses the same first back arm  20  and first base arm  40  but uses a different middle arm, namely, the third middle arm  400 . In this alternative embodiment, third middle arm  400  is a long plate having a first slot  432  and a second slot  434  near each end portion  431  and  433  respectively and, having one straight lock bar  435  along the axis connecting slots  432  and  434 , with a first lock end  436  and a second lock end  437 , placed on generally the center position of third middle arm  400  extending next to and in between slot  432  and  434  respectively. Through first and second openings  28  and  29  on first back arm, and first slot  432  on third middle arm, first back arm  20  and third middle arm  400  are engaged by a first mounting screw  50  and first nut  51  through which third middle arm  400  may freely rotate and slide along first slot  432 . Similarly, through second slot  434  on third middle arm  400  and first opening  48  on first base arm  40 , third middle arm  400  and first base arm  20  are engaged by a second mounting screw  52  with a second nut  53  through which first base arm  40  may freely rotate and slide along second slot  434 . This single lock bar type pivot arm mechanism allows first back arm  20  and first base arm  40  be tilted, without any initial limiting position and in virtually any direction and in any order, and be locked into any position where the recesses are located, namely, recesses  22  or  24  on first back arm  20  and  42  or  44  on first base arm  40 , by moving single lock bar  435  into corresponding recessed portions on first back arm  20  and first base arm  40  respectively. 
     In yet another implementation as shown in FIG. 20, a second back arm  600  and a second base arm  800  are essentially the same as those used in the above mentioned implementations, except that in this implementation, second back arm  600  and second base arm  800  have multiple recessed portions  622  and  842  respectively, to receive a gear mechanism. In this implementation, a fourth middle arm  700  is a long plate having a first and a second opening  732  and  734  near each end portion  731  and  733  respectively and, having a first round gear  740  placed on generally the center position of fourth middle arm  700 . First gear  740  has a handle bar  737  perpendicularly connected at center position of first gear  740  for ease of operation. First gear  740  is connected to fourth middle arm  700  through an extendable pin mechanism  739  such that first gear  740  may be pulled or pushed perpendicularly, outwardly or inwardly to disengage or engage the single gear lock mechanism respectively. There are multiple receiving cavities  735  on first gear  740  surrounding its center along an equal radius line to receive a third lock pin  736  which is connected to fourth middle arm  700  along the same radius line and on the same side surface where first gear  740  is placed. Through first and second openings  628  and  629  on second back arm  600  and first opening  732  on fourth middle arm  700 , second back arm  600  and fourth middle arm  700  are engaged by a first mounting screw  50  and a second nut  51  through which fourth middle arm  700  may freely rotate. Similarly, through a second opening  734  on fourth middle arm  700  and first opening  848  on second base arm  800 , fourth middle arm  700  and second base arm  800  are engaged by a second mounting screw  52  with a second nut  53  through which second base arm  800  may freely rotate. When first gear  740  is pulled out and disengaged, this single gear lock mechanism allows second back arm  600  and second base arm  800  be tilted without any initial limiting position and in virtually any direction and in any order and, be locked into any position where the recesses, namely  622 ,  738  and  842 , are located by engaging first gear  740  inwardly and placing third lock pin  736  into one of the receiving cavities  735  on first gear  740 . 
     In yet another implementation as shown in FIG. 21, a third back arm  1000  and a third base arm  1100  are the same as those used in the above mentioned single gear implementation except that the spacing of the multiple recesses may be different due to different gear diameters. In this implementation, a fifth middle arm  900  is a long plate having a first and second opening  932  and  934  near each end portion  931  and  933  respectively and, having a second round gear  950  and third round gear  960  engaged with each other and placed on fifth middle arm  900  such that second and third gears  950  and  960  may engage with multiple recesses  1022  and  1142  on third back and third base arms respectively. Through first and second openings  1028  and  1029  on third back arm  1000  and first opening  932  on fifth middle arm  900 , third back arm  1000  and fifth middle arm  900  are engaged by a first mounting screw  50  with a first nut  51  through which fifth middle arm  900  may freely rotate. Similarly, through second opening  934  on fifth middle arm  900  and first opening  1148  on third base arm, fifth middle arm  900  and third base arm  1100  are engaged by a second mounting screw  52  with a second nut  53  through which third base arm  1100  may freely rotate. Second gear  950  has a handle bar  937  perpendicularly connected at the center position of second gear  950  for ease of operation. Second gear  950  is connected to fifth middle arm  900  through an extendable pin mechanism  939  such that second gear  950  may be pulled or pushed perpendicularly, outwardly or inwardly to disengage or engage the double gear lock mechanism respectively. Third gear  960  is connected at its center by a sixth screw  945  with a sixth nut  946  to fifth middle arm  900 . There are multiple receiving cavities  935  on second gear surrounding its center along an equal radius line to receive a fourth lock pin  936  which is connected to fifth middle arm  900  along the same radius line and on the same side surface where second gear  950  is placed. When second gear  950  is pulled out and disengaged, this double gear pivot arm mechanism allows third back arm  1000  and third base arm  1100  be tilted without any initial limiting position and in virtually any direction and in any order and, be locked into any position where the recesses, namely  1022 ,  938 ,  950  and  1142 , are located by engaging second gear  950  inwardly and placing fourth lock pin  936  into one of the receiving cavities on second gear  950 . 
     The boat seat may be easily operated by a user. In the lock pin type implementation, a user needs only to apply a pulling force on first seat back  500  away from first seat base  100  to disengage or engage lock pins  36  and  38  on first middle arm  30  from recesses  22  or  24  on first back arm and  41  or  44  on first base arm respectively, so that a tilting and locking of first seat back  500  or first seat base  100  may be achieved. The same applies to the alternative implementations for first back arm  20  and first base arms  30 . In the latch type implementation, a user needs only to apply a pivotal force clock wise or counter clock wise, depending upon the initial position when rotating lever  357  was connected with coupling brackets  355  and  359 , to disengage or engage latches  353  and  361  from the above mentioned recesses whereby a tilting and locking of first seat back or first seat base is achieved. Optionally, a handle may be attached to rotating lever  357  to ease the operation. The operation of the single lock bar type implementation is identical to the lock pin mechanism. In the single gear implementation, a user needs only to disengage first gear  740  by pulling handle bar  737  outwardly and then rotate either seat back  500  or seat base  100  to a desired position and, engage first gear  740  with recesses  622  on second back arm  600  and recesses  842  on second base arm  800  by placing handle bar  737  inwardly such that third lock pin  736  locks into one of the receiving cavities  735 . Similarly, in the double gear mechanism, a user needs to disengage second gear  950  by pulling handle bar  937  outwardly and then rotate either seat back  1000  or seat base  1100  to a desired position and, engage second gear  950  with third gear  960  and recesses  1022  on third back arm  1000  and recesses  1142  on third base arm  1100  by placing handle bar  937  inwardly such that fourth lock pin  936  locks into one of the corresponding receiving cavities  935 . 
     Although the embodiments described according to the invention have utilized, for pivoting or rotation purposes, screws, bolts, pins, rivets or gears, it is clear that any other solutions, such as ratchets, for example, are also suitable. 
     The advantage of the boat seat according to the invention can therefore be seen, which not only enables the seat back be in a semi folded position, a substantially vertical position or substantially horizontal position whereby providing different uses for a user, the seat can also be arranged to be completely folded down by rotating the upper and lower cushions towards each other whereby the seat can be conveniently transported and stored. 
     While this invention has been described as having an exemplary design, the present invention may be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains.