Abstract:
The invention described relates to a downrigger line clamp mechanism used in downrigger fishing and includes an adjustable clamping force for adjusting the overall release tension of a fishing line. The pre-stressed line clamp mechanism includes a pair of pivotally engaged, elongate arms which, when assembled, are resiliently flexed such that one portion of the arms, the proximal grip portions, are outward bowed, the tips of the proximal grip portions pinching together, thereby biassing another portion of the arms, the jaws, towards a closed clamp position. The line clamp mechanism uses an adjustable compression-force biassing device movably mounted between the tips of the proximal grip portions of the arms. The biassing device may include spacers of different spacing dimensions, each spacer being positionable into an active position between the tips of the proximal grip portions of the arms by moving the biassing device relative to the arms. The magnitude of clamping force at the jaws is adjustable by adjusting the spacing between the tips of the proximal grip portions of the arms.

Description:
FIELD OF THE INVENTION  
         [0001]    The invention relates generally to a downrigger line clamp mechanism used in downrigger fishing.  
         BACKGROUND OF THE INVENTION  
         [0002]    When trolling for fish, a downrigger assembly can be used to control the depth at which the lure is trolled through the water. A downrigger typically comprises a weight suspended from the boat by a downrigger cable; and a leader line, one end of which is clipped to the downrigger cable and the other end of which is clipped to the fishing line, typically 10 to 30 feet from the lure, with a line clamp. When trolling with a downrigger, the fishing line runs substantially vertically from the fishing rod to the line clamp and substantially horizontally (depending on the trolling speed, and the drag of the lure and line) from the release clamp to the lure.  
           [0003]    When a fish is hooked, it is necessary for the line clamp to release the fishing line so that fish can be played free of the hindrance of the weight, and brought aboard without tangling the fishing line and the cable. To operate properly, the line clamp must retain the fishing line during trolling and release the fishing line when a fish strikes the lure. Typically, persons fishing desire different line clamp release tensions depending on the fishing technique and the type of fish being sought. It is therefore advantageous to be able to adjust the line clamp release tension.  
           [0004]    Most downrigger line clamps use a coil compression spring to bias two pivoting clamping surfaces towards a closed position wherein a fishing line may be frictionally held between the clamping surfaces. Such systems are described in U.S. Pat. No. 5,784,826 (Walker, Jul. 28, 1998), U.S. Pat. No. 5,950,349 (Walker, Sep. 14, 1999), U.S. Pat. No. 5,979,104 (Walker, Nov. 9, 1999), U.S. Pat. No. 4,698,933 (Shaw, Oct. 13, 1987), and U.S. Pat. No. 5,163,246 (Shaw, Nov. 17, 1992).  
           [0005]    With the foregoing line clamps, the friction holding the fishing line between the clamping surfaces will vary depending upon the character and condition of the line as well as the specifics of the surface-to-surface contact of the clamping surfaces with the line that happen to occur in a given clamping event. In other words, for a given clamping compressive force, the force of friction will vary from one clamping event to the next, and consequently the line release force will also vary somewhat.  
           [0006]    The pivot-based line clamps of the foregoing sort enable the person using them to vary the release tension by changing the position of the fishing line between the clamping surfaces. Specifically, a fishing line is more readily released from between the clamping surfaces if the fishing line is positioned near the ends of the clamping surfaces than if the fishing line is positioned closer to the pivot. The leverage is greater and the release tension is higher near the pivot point than they are further away from the pivot point.  
           [0007]    It is therefore possible to make minor adjustments to the line clamp release tension by carefully positioning the fishing line between the clamping surfaces. In practice, however, such previously known pivot-type clamps are effective to provide only a fairly limited range of release tensions. Accordingly, several of these aforementioned patented systems describe additional structure and/or techniques for enabling various release tensions of the fishing line, namely by providing auxiliary means for adjusting the compression force between the clamping surfaces. In particular, U.S. Pat. Nos. 5,784,826, 5,950,349, and 5,979,104 describe a cam lever adjustment assembly wherein a threaded rod is inserted through a bore through the clamping surfaces. The ends of the threaded rod protrude from the outer clamping surfaces and may be threadedly engaged by any one of a number of different types of internally threaded rod caps each of which may be tightened or loosened to vary the compression adjustment between the clamping plates. Typically, the rod caps have wings, knurled surfaces or other projections, to make it easier to turn them by hand.  
           [0008]    One disadvantage of the aforementioned prior designs is that the compression force adjustment devices are somewhat finicky to operate, which can be a hindrance for a fisherman whose hands are already occupied with fishing line, lures, flashers, and bait, and whose hands may be somewhat greasy as a consequence.  
           [0009]    Furthermore, the aforementioned designs do not permit a smooth flow of water over the surfaces of the line clamp. In the aforementioned designs, coil springs, thumb or wing nuts, and levers protrude beyond the body of the fishing line clamp, thereby causing turbulence around the line clamp as it passes through the water. An unbalanced line clamp or a line clamp that is not streamlined may twist the fishing line and reduce the performance of the lure. Furthermore, a fishing line may hang up the protrusions of the line clamp, thereby leading to tangled lines.  
           [0010]    Another type of prior line clamp is described in U.S. Pat. No. 5,921,015 (Newell et al., Jul. 13, 1999). As with the aforementioned line clamp designs, this patent describes a line clamp having two pivoted clamping plates between which a fishing line may be frictionally held. Unlike the aforementioned designs, however, rather than using a coil compression spring to clamp together the plates, the elongated clamping plates are sandwiched together by a rigid sliding clamp that slides along the outer surfaces of the elongated clamping plates from the pivot towards the ends of the plates and locks in place when the clamp is in the correct position to provide a desired clamping force.  
           [0011]    As with the previously mentioned coil-spring-based line clamp, the line clamp described in U.S. Pat. No. 5,921,015 is fairly complex and expensive to manufacture; the overall shape of the line clamp is not streamlined and the sliding clamps are difficult to operate.  
           [0012]    What is required is a simple, streamlined line clamp with a simple, easy-to-operate compression force adjustment device that enables a suitable range of release tensions of the fishing line.  
         SUMMARY  
         [0013]    An object of the invention is to provide a line clamp mechanism having means for adjusting the line clamp compression force that is simple, streamlined and relatively inexpensive to manufacture. As in other previously known downrigger clamp designs, the fishing line is releasably frictionally held within the downrigger line clamp, permitting the fishing line to be pulled from the downrigger line clamp by a fish striking the lure. According to one aspect of the invention, there is provided a pre-stressed line clamp mechanism having the following components:  
           [0014]    (a) first and second elongate arms each made of suitable selected elastic material and each having a clamping jaw at its distal end, a compression-adjusting end at its proximal end, and an outwardly bulging arcuate grip portion intermediate the clamping jaw and the compression-adjusting end;  
           [0015]    the second elongate arm being longitudinally generally coextensive with the first elongate arm, and oriented in opposition to the first elongate arm so that, the clamping jaws of the two arms present opposed clamping faces, preferably generally planar and generally parallel to one another, suitable for clamping a line therebetween, and the compression-adjusting ends of the two arms present opposed abutting surfaces;  
           [0016]    (b) a coupling means such as a pivot pin or equivalent on which both the arms are pivotally mounted, to provide pivoting of the distal portions of the arms through a small angular range about a pivotal axis located near the distal ends of the arms, the clamping jaws extending distally away from the pivot pin and the grip portions extending proximally away from the pivot pin;  
           [0017]    the outwardly-bulging grip portions of the opposed arms forming a grip that under compressive force exerted by the user&#39;s hand forces disengagement of the clamping faces to permit insertion or release of a fish line, and in rest position are stressed so as to exert a compressive force against one another at the abutting surfaces, thereby biassing the clamping jaws together toward a closed clamping position in which clamping force may be applied to a fish line inserted and held between the clamping faces; the amount of clamping force being variable with distance from the pivot pin; the material, shape and dimensions of the arms being selected so that within engineering tolerances, the compressive force exerted by the clamping jaws on the fish line, and consequently the release tension of the fish line, are within predetermined selected ranges;  
           [0018]    (c) leader line attachment means connected to the proximal end of at least one of the arms and preferably both arms; and  
           [0019]    (d) an adjustable compression-force biassing device movably mounted between the compression-adjusting ends of the arms, the biassing device having one or more spacers, or one or more spacers and an abutment opening within which the opposed abutting surfaces of the compression-adjusting ends can abut, so as to selectably provide at least two different spacing dimensions between the abutting surfaces of the compression-adjusting ends; one bearing surface of each said spacer making sliding contact with an abutting surface of the compression-adjusting end of an associated one of the arms, and the other bearing surface of each said spacer making sliding contact with an abutting surface of the compression-adjusting end of the other of the arms; each spacer or abutment opening being positionable into an active position relative to the abutting surfaces of the compression-adjusting ends by moving the biassing device distally or proximally relative to the arms;  
           [0020]    wherein the magnitude of the compression force exerted by the jaws is adjustable by adjusting the distal/proximal position of the biassing device relative to the arms.  
           [0021]    In a preferred embodiment, the adjustable compression-force biassing device is mounted for distal/proximal displacement relative to the arms, the spacers, or the spacers and the abutment opening, being disposed in longitudinal series, each spacer or the abutment opening occupying a short portion of the longitudinal length of the biassing device and in turn brought into active position as the biassing device is proximally or distally displaced. Further, to prevent unwanted proximal or distal displacement that could, if permitted, present an unwanted spacer or the abutment opening in the active position relative to the abutting surfaces of the compression-adjusting ends, the biassing device is provided with active position stabilizers, such as ridges that engage mating slots, steps, rails, abutments or the like, that impede longitudinal displacement of the biassing device once a selected spacer is in the active position. The user may, by exerting a proximally or distally directed force on the biassing device, move the biassing device so that the spacer, or the abutment opening, that was in active position is displaced out of active position and replaced by the next spacer in the series.  
           [0022]    For most purposes, a biassing device that includes two different spacers in longitudinal series, or an abutment opening and a spacer in longitudinal series; and therefore provides two available different line clamping forces at any given position of the line between the clamping jaws, suffices.  
           [0023]    Also in the preferred embodiment, sleeves or sheaths are provided for the clamping jaws that envelope the clamping jaws. These sleeves or sheaths may advantageously be provided with relatively high-friction clamping surfaces overlying the clamping faces of the clamping jaws. A securing device such as a slot in the sleeve or sheath that engages a projection on the outward-facing side of the associated clamping jaw impedes unwanted removal of the sleeve or sheath from the clamping jaw. Reference in this specification to the clamping jaws or the clamping faces should be understood to include the possibility that the composite clamping jaws may include such sleeves or sheaths and that the clamping surfaces are formed by opposed relatively flat portions of the sleeves or sheaths. The sleeves or sheaths provide enhanced gripping and increased cushioning of the fishing line.  
           [0024]    The shape, dimensions and material of the arms are selected to enable the arms to resiliently flex when the line clamp mechanism is being assembled, thereby to pre-stress the clamping mechanism. What has been referred to in the interest of simplification as a “pivot pin” is preferably a pair of gudgeons, a respective one of which is moulded on each arm proximally to the clamping jaw, and a pin insertable through the gudgeons to provide the pivoting connection. The stress occurs because when the arms are not attached to each other and are disposed in relaxed opposed relationship with their compression-adjusting ends in contact and their clamping surfaces in contact, the bow-like shaping of the arms from one end to another results in a misalignment of the gudgeon holes in the first arm with the gudgeon holes in the second arm, in that the portion of each arm proximate to the gudgeons is outward of the position where the gudgeon holes would align. The arms must be forced inwardly toward one another to enable them to be coupled together by the pivot pin. The result, when the arms are thus coupled together, is a compressive force exerted by the clamping jaws. This compressive force may be released by pressing the gripping portions of the arms inwardly toward one another. The rest compressive clamping force may be adjusted by adjusting the spacing between the compression-adjusting ends of the arms, and this spacing adjustment is accomplished in the preferred embodiment by varying the longitudinal position of the biassing device, thereby to provide as many different spacings between the compression-adjusting ends of the arms as there are spacers. Further note that, as mentioned above, in one position of the biassing device, there need not be a spacer interposed between the compression-adjusting ends; these ends may abut one another within the abutment opening.  
           [0025]    Preferably, each arm is smoothly convexly outwardly curved to distribute the stress throughout the arm, and to provide an aesthetically pleasing design that is both streamlined (for facilitating minimization of turbulence as the line clamp passes through the water), and ergonomic (for ease of gripping and squeezing). The arms desirably have maximum curvature towards their proximal ends and may suitably straighten in the vicinity of the pivot pin. Other shapes may better facilitate minimization of turbulence. Other shapes may be selected at the preference of the designer if they at least provide a suitable gripping means and downrigger attachment means, provide the requisite resilient flexing when the line clamp mechanism is being assembled, and provide pre-stressing of the arms when assembled so that a compressive force exists between the clamping jaws, releasable upon compression of the gripping means. The arms are preferably moulded from a hard durable plastic material such as a suitable acetal resin or composite, but may also be suitably formed by other known means, and made from other similarly resiliently flexible and durable materials. The transverse dimension of each arm may be varied from distal to proximal end to provide adequate surface contact of the line within the clamping jaws while avoiding a cumbersome grip. The thickness of the arms may be varied, preferably ranging from a maximum in the vicinity of the clamping jaws and a minimum near the compression-adjusting ends of the arms, for ease of squeezing. The inner portions of the arms on the proximal side of and nearer the pivot pin may be provided with proximally/distally extending stiffeners for greater resistance to flexing in those portions of the arms.  
           [0026]    In this specification, including the claims, the following words have the following meanings:  
           [0027]    (a) The words “distal” and “proximal” refer to the respective ends and proximate parts of the line clamp relative to the position of the downrigger cable when the line clamp is in use. The distal end of the line clamp is the end of the line clamp that is furthest from the downrigger cable during normal trolling, and the proximal end of the line clamp is the end of the line clamp that is closest to the downrigger cable during normal trolling.  
           [0028]    (b) The words “inward” and “outward” are used relative to an imaginary plane roughly defined by the opposed contacting jaw surfaces of the clamp, the imaginary plane being perpendicular to the compressive clamping force. An inward direction is one towards the imaginary plane from either side of the imaginary plane. An outward direction is one away from either side of the imaginary plane.  
           [0029]    (c) The transverse dimension is the dimension lying within the imaginary plane and perpendicular to the longitudinal dimension.  
           [0030]    The leader line attachment means is suitably a hole through the compression-adjusting end of each arm. The biassing device is preferably moulded, with its spacer or spacers, as a single integral unit, and is configured so that it may be easily inserted and secured between the compression-adjusting ends of the arms, providing at its proximal end a relatively large opening that affords ample clearance for insertion of the leader line into the leader attachment means in the compression-adjusting ends of the arms. The terminating portions of the compression-adjusting ends of the arms may be slightly outwardly bent for ease of insertion of the biassing device therebetween.  
           [0031]    In the operation of the line clamp mechanism according to this aspect of the invention, the jaws are opened to receive a fishing line by squeezing together the squeezable grip portions of the arms. The release tension required to release the fishing line from between the jaws of the line clamp is in part dependent upon the positioning of the fishing line within the jaws; the compression force of the jaws is less towards the distal ends of the jaws and increases in the proximal direction toward the pivot pin. Furthermore, the biassing device may be used to adjust the compression force between the jaws by moving one of the spacers thereof into an active position between the compression-adjusting ends of each arm; the greater the spacing dimension between the compression-adjusting ends of the arms, the higher the compression force between the jaws.  
           [0032]    With line clamps where the release tension is low, the compressive force between the compression-adjusting ends is also relatively low and the compression-adjusting ends do not grip the biassing device as tightly as they do when the compressive force is relatively high. In a preferred embodiment, for use in line clamps where a low release tension is desired, the compression-adjusting end of one arm has an inwardly projecting peg and the compression-adjusting end of the other arm has a hole sized, shaped and positioned to slidably mateably engage the peg. The peg has a leader line hole through which a leader line can be inserted. The peg is contained within a slot in the biassing device and thereby acts to prevent the biassing device from being dislodged from between the compression-adjusting ends.  
           [0033]    The invention as described above offers several features over the prior line clamp mechanisms. Firstly, since the compression force between the jaws is provided by the resilience of the plastic arms, the line clamp according to the preferred embodiment of the invention is suitably more streamlined than conventional line clamps which are required to incorporate coil springs, compression clamps and thumb, or wing, nuts into the design. Secondly, as opposed to the fishing line clamp pads as used in prior line clamps, the soft grip jacket functions both to cushion the fishing line as well as shield the fishing line from the pivot, thereby helping to reduce fishing line hangups. Thirdly, the line clamp mechanism includes a simple biassing device to adjust the compression force between the jaw surfaces of the line clamp mechanism thereby adjusting the amount of tension which is required to release the fishing line from between the jaws. Lastly, with the exception of the jacket, the entire line clamp mechanism is made from an acetal composite. All components of the line clamp mechanism may be made of materials selected to be essentially impervious to harm from immersion in fresh or salt water. The line clamp is relatively inexpensive to manufacture and easy to assemble, and may, if suitably designed in accordance with the teachings herein, be operated with one hand.  
           [0034]    The various features of novelty that characterize the invention are pointed out with more particularity in the claims annexed to and forming part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be made to the accompanying drawings and descriptive matter in which there are illustrated and described preferred embodiments of the invention. 
       
    
    
     SUMMARY OF THE DRAWINGS  
       [0035]    [0035]FIG. 1 is a perspective view of a preferred embodiment of the assembled line clamp constructed in accordance with the invention.  
         [0036]    [0036]FIG. 2 is a perspective exploded view of the components of the line clamp of FIG. 1.  
         [0037]    [0037]FIG. 3 is a perspective view of an arm of the line clamp of FIG. 1.  
         [0038]    [0038]FIG. 4 is a perspective view of a preferred embodiment of the biassing device for the line clamp of FIG. 1.  
         [0039]    [0039]FIG. 5 is an plan view of the biassing device shown in FIG. 4.  
         [0040]    [0040]FIG. 6 is a transverse sectional view of the biassing device shown in FIG. 5, taken along the line  6 - 6  in FIG. 5.  
         [0041]    [0041]FIG. 7 is a perspective view of the arms of an alternative embodiment of the line clamp suitable for use where a low release tension is desired.  
         [0042]    [0042]FIG. 8 is a perspective exploded view of the components of an alternative embodiment of the line clamp including the arms shown in FIG. 7.  
         [0043]    [0043]FIG. 9 is a perspective view of the assembled line clamp of FIG. 8.  
         [0044]    [0044]FIG. 10 is a perspective view of the biassing device shown in FIG. 9.  
         [0045]    [0045]FIG. 11 is a plan view of the biassing device shown in FIG. 10.  
         [0046]    [0046]FIG. 12 is a transverse sectional view of the biassing device shown in FIG. 11 taken along the line  12 - 12  in FIG. 11. 
     
    
     DETAILED DESCRIPTION  
       [0047]    Referring to FIGS. 1 and 2, there is shown a line clamp  10  according to the preferred embodiment of the invention, comprising two arms  12 , a jacket  14 , a pin  16  and a biassing device  18 .  
         [0048]    The arms  12 , are identical to each other, with one being rotated 180 degrees about its longitudinal axis with respect to the other. Each arm  12  (FIG. 3) comprises a compression-adjusting end  20 , a grip portion  22 , a pivot component  24  and a jaw stub  26 .  
         [0049]    Each compression-adjusting end  20  has a leader line hole  30  and an inwardly-facing abutting surface  32 . In use the leader line (not shown) is passed through the leader line hole  30 .  
         [0050]    The proximal and distal portions of the compression-adjusting end  20  adjoining the abutting surface  32  bend outwardly so as to smoothly bevel the transversely extending proximal and distal edges of the abutting surface  32 .  
         [0051]    Each grip portion  22  extends from proximate to the compression-adjusting end  20  to proximate to the pivot component  24 . Each grip portion  22  has an outward bulge  34  at its proximal end and, with respect to inward or outward deflection, is substantially straight from the outward bulge  34  to the distal end of the grip portion  22 . Each grip portion  22  tapers from wider at its distal end to narrower at its proximal end in both its transverse and inward/outward dimensions. Each grip portion  22  has a washboard hold  36  on its outwardly facing surface. Each grip portion  22  has a proximally/distally-extending, substantially-planar, stiffener  38  disposed normal to, and transversely centred in, its inwardly facing surface. The stiffener  38  extends from proximate to the compression-adjusting end  20  to proximate to the pivot component  24 . The stiffener  38  has its greatest inward/outward thickness roughly mid way along its length and smoothly tapers to minimal thickness at each end.  
         [0052]    Each pivot component  24  comprises a pair of inwardly-projecting gudgeons  52 . The gudgeons  52  are transversely spaced apart a distance roughly equal to the transverse thickness of one gudgeon  52  and each pair is transversely offset from being centred on the transverse centre of the arm  12  a distance roughly equal to half the transverse thickness of one gudgeon  52 . This positioning of the gudgeons  52  permits one pair of gudgeons  52  to interlock with the other pair of gudgeons  52  wherein one gudgeon  52  of each pair is interposed between the gudgeons  52  of the other pair.  
         [0053]    As shown in FIGS. 1 and 2, the pin  16  is inserted through the two pairs of gudgeons  52 . The pin  16  is preferably made of a hard durable plastic, but may be made of a variety of other suitable materials. It is preferable that the pin  16  be resistant to corrosion caused by immersion in fresh or salt water.  
         [0054]    Although, it is possible to have only one gudgeon  52  on each arm  12 , generally, at least two gudgeons  52  for each arm  12  are required for stability, and more gudgeons  52  may be used at the expense of increased manufacturing costs.  
         [0055]    Each jaw stub  26  has a stub projection  60  on its outwardly facing surface. Each stub projection  60  has a proximal side substantially normal to the outwardly facing surface of the jaw stub  26  and a wedge-shaped distal side. In the embodiment shown in FIGS. 1, 2 and  3 , the stub projection  60  is a transversely extending projection. In the embodiment shown in FIGS. 7, 8 and  9 , the stub projection  60  is an obliquely-truncated cylindrical projection.  
         [0056]    The arms  12  are made from a resiliently-bendable material. The shape of the arms  12  permits bending of the arms  12  in the inward/outward dimension and resists bending of the arms  12  in the transverse dimension. It is preferable that the arms  12  be resistant to corrosion caused by immersion in fresh or salt water. The arms  12  are preferably made of a hard resiliently-bendable durable plastic such as acetal, but may also be made from other similarly resiliently-bendable materials.  
         [0057]    The jacket  14  is made up of two sheaths  70 , each sheath  70  having an outward side, an inwardly-facing jaw surface  72  and an internal cavity, each cavity being sized and shaped to contain a jaw stub  26 . The two sheaths  70  are pivotally connected at the proximal edges of their jaw surfaces  72 .  
         [0058]    The jacket  14  provides jaw surfaces  72  that are soft so that they will tend not to damage the fishing line and that increase the friction between the jaw surfaces  72  and the fishing line, relative to jaws of the same material from which the arms  12  are made, so that the same release tension can be obtained with less compressive force between the jaw surfaces  72 . As well the pivotal connection at the proximal edges of the jaw surfaces  72  prevents a fishing line inserted between the jaw surfaces  72  from contacting, and being harmed by or entangled in, the pivot components  24 .  
         [0059]    It is preferable that the jacket  14  be made of a soft flexible material which is resistant to harm from immersion in fresh or salt water. In the embodiments shown in the drawings, the jacket  14  is made of polyurethane, but it can also be made of other suitable materials.  
         [0060]    Each sheath  70  has a sheath hole  74  through its outward side, sized and shaped to engage with the associated stub projection  60  when the jaw stubs  26  are inserted into the sheaths  70 . In the embodiment shown in FIGS. 1 and 2, the sheath hole  74  is a transversely extending slot. In the embodiment shown in FIGS. 8 and 9, the sheath hole  74  is circular. During insertion of the jaw stubs  26  into the sheaths  70 , the wedge-shaped distal edge of the stub projection  60  outwardly deforms the outward side of the sheath  70 , until the stub projection  60  aligns with the sheath hole  74 , thereafter the proximal side of the stub projection  60  abuts the proximal side of the sheath hole  74 , so as to retain the jaw stub  26  within the sheath  70 .  
         [0061]    In the embodiment shown in FIGS. 1, 2,  4 ,  5  and  6 , the biassing device  18  has sidewalls  80 , a proximal end wall  82 , a distal end wall  84 , a spacer  86 , a centring wedge  88  and an abutment opening  90 . The side walls  80  have knurls  92  on their exterior faces to facilitate hand manipulation of the biassing device  18 . The proximal end wall  82  is curved, with its distal side roughly conforming to the rounded shape of the proximal tips of the compression-adjusting ends  20 .  
         [0062]    The spacer  86  is inwardly/outwardly centred on, and contiguous with, the sidewalls  80  and the distal end wall  84 . The spacer  86  has a spacer leader notch  94  and two oppositely-disposed outward-facing bearing surfaces  96 . Each bearing surface  96  has a active position stabilizer, such as a transversely-extending retainer ridge  98  at its proximal edge. The bearing surfaces  96  are substantially normal to the sidewalls  80 . The distal end wall  84  is thicker where it meets the spacer  86  than it is at its outward edges, wherein the proximal faces of the distal end wall  84  slope and meet the spacer  86  at an angle of greater than 90 degrees.  
         [0063]    The centring wedge  88  is inwardly/outwardly centred on, and contiguous with, the proximal end wall  84 . The centring wedge  88  has a wedge leader notch  100 . The centring wedge  88  is thickest at its proximal end and tapers to minimal thickness at its distal edge.  
         [0064]    The abutment opening  90  is the space between the sidewalls  80 , distal of the centring wedge  88  and proximal of the spacer  86 . The spacer leader notch  94  and the wedge leader notch  98  are contiguous with the abutment opening  90 .  
         [0065]    As shown in FIG. 1, when the line clamp  10  is assembled, the pin  16  is inserted into the gudgeons  52 ; the jaw stubs  26  are inserted into the jacket  14 ; and the compression-adjusting ends  20  are disposed within the biassing device  18 .  
         [0066]    The assembled line clamp  10  is pre-stressed, in that even when the abutting surfaces  32  are abutting each other and nothing is interposed between the jaw surfaces  72 , a compressive force exists between the jaw surfaces  72 . This is so because the arms  12  and jacket  14  are configured such that compression-adjusting ends  20  and the jaw stubs  26  are outwardly flexed, and the pivot components  24  are inwardly flexed, in the assembled line clamp  10 , even when the abutting surfaces  32  are abutting each other and nothing is interposed between the jaw surfaces  72 .  
         [0067]    In the embodiment shown in FIGS. 1, 2,  4 ,  5  and  6 , the biassing device  18  provides two active positions for the compression-adjusting ends  20  within the biassing device  18 : low release tension and high release tension. In the low release tension position, shown in FIG. 1, the proximal tips of the compression-adjusting ends  20  are adjacent to the distal faces of the proximal end wall  82 ; the abutting surfaces  32  are abutting each other within the abutment opening  90 ; the outwardly-bent portions of the compression-adjusting ends  20  proximal to the abutting surfaces  32  are disposed on either side of the centring wedge  88 ; and the leader line, if such has been inserted through the leader line holes  30 , is disposed within the wedge leader notch  100 . The centring wedge  88  acts to keep the biassing device  18  centred in the inward/outward dimension relative to the compression-adjusting ends  20 .  
         [0068]    In the high release tension position (not shown), the spacer  86  is interposed between the compression-adjusting ends  20 . The abutting surfaces  32  each abut an associated bearing surface  96 ; the proximal edges of the abutting surfaces  32  are adjacent to the distal sides of the associated retainer ridges  98 ; the portions of the compression-adjusting ends  20  distal to the abutting surfaces  32  are adjacent to the proximal faces of the distal end wall  84 ; and the leader line, if such has been inserted through the leader line holes  30 , is disposed within the spacer leader notch  94 . The increased flexing of the arms  12  caused by interposing the spacer  86  between the compression-adjusting ends results in increased compressive force between the jaw surfaces  72 .  
         [0069]    In both the low release tension and high release tension positions the sidewalls  80  prevent the biassing device  18  and compression-adjusting ends  20  from moving transversely relative to each other. When the compression-adjusting ends  20  are in the low release tension position, the proximal end wall  82  prevents the biassing device  18  from moving distal relative to the compression-adjusting ends  20 , and the spacer  86  and retainer ridges  98  impede, but do not prevent, proximal movement of the biassing device  18  relative to the compression-adjusting ends  20 . The outward bend of the distal portions of the compression-adjusting ends  20  adjoining the abutting surfaces  32  permits the spacer  86  and retainer ridges  98  to wedge between, and spread, the compression-adjusting ends  20  when sufficient distal force is applied to the biassing device  18  relative to the arms  12 . Similarly, when the compression-adjusting ends  20  are in the high release tension position, the retainer ridges  98  impede, but do not prevent, distal movement of the biassing device  18  relative to the compression-adjusting ends  20 . The outward bend of the proximal portions of the compression-adjusting ends  20  adjoining the abutting surfaces  32  permits the retainer ridges  98  to wedge between, and spread, the compression-adjusting ends  20  when sufficient proximal force is applied to the biassing device  18  relative to the arms  12 . As well, when the compression-adjusting ends are in the high release tension position, the distal end wall  84  impedes, but does not prevent, the biassing device  18  from moving proximal relative to the compression-adjusting ends  20 , so as to permit the biassing device  18  to be removed from between the compression-adjusting ends  20 . The sloped proximal faces of the distal end wall  84  wedge between, and spread, the compression-adjusting ends  20  when sufficient proximal force is applied to the biassing device  18  relative to the arms  12 .  
         [0070]    In use, a leader line (not shown) is threaded through the leader line holes  30  and formed into an eye, typically by crimping a sleeve around the body and tail of the leader line. The user spreads the jaw surfaces  72  by flexing the grip portions  22  inward by hand, typically after ensuring that the compression-adjusting ends  20  are in the low release tension position so as to require less effort to spread the jaw surfaces  72 . If the grip portions  22  are flexed inward sufficiently far, the stiffeners  38  will contact each other at their inward edges, preventing further flexing of the grip portions  22  and thereby preventing the grip portions  22  from being weakened or broken due to over-flexing.  
         [0071]    The user places a section of fishing line between the jaw surfaces  72  and, when satisfied with the position of the fishing line, releases the grip portion  22  so as to clamp the fishing line between the jaw surfaces  72 . Typically, the user carefully positions the fishing line between the jaw surfaces  72  so as to adjust the release tension, in that as with most pivot-based line release clamps, moving the fishing line proximal, and thus closer to the pin  16 , increases the release tension and moving the fishing line distal, and thus farther from the pin  16 , decreases the release tension.  
         [0072]    The user can adjust the release tension by positioning the compression-adjusting ends  20  in the low release tension or the high release tension position in the biassing device  18 . The compression-adjusting ends  20  and biassing device  18  make audible clicks as the compression-adjusting ends  20 , due to their resilient nature, snap into position. Once the user has, by manipulating the position of the fishing line between the jaw surfaces  72  and adjusting the position of the compression-adjusting ends  20  in the biassing device  18 , obtained the desired release tension the user lowers the gear into the water to troll.  
         [0073]    Another embodiment of the line clamp, of particular use where a lower release tension, and therefore a smaller line clamp, are required, is shown in FIGS. 7, 8,  9 ,  10 ,  11  and  12 . As shown in FIG. 7, the peg small compression-adjusting end  200  has an inwardly-projecting peg  202 . In the embodiment shown, the peg  202  has curved sides, but is not cylindrical, being larger in the longitudinal dimension than it is in the transverse dimension. The hole small compression-adjusting end  204  has a peg hole  206  sized shaped and positioned to slidably mate with the peg  202  so as to permit the peg small compression-adjusting end  200  and the hole small compression-adjusting end  204  to move inwardly and outwardly relative to each other. The peg  202  has a peg leader line hole  208  through which a leader line (not shown) is inserted during use.  
         [0074]    In another embodiment (not shown) the small compression-adjusting ends each have a peg hole. A removable peg, having a leader line bore, a shaft, a shoulder and a head, is inserted into the peg holes. The shaft has a diameter less than the peg holes and passes easily through the peg holes. The shoulder is only long enough to contact one of the peg holes when inserted. The shoulder has a diameter substantially the same as the peg holes. The shoulder must be forced into the peg hole and is frictionally retained within the peg hole. The head has a diameter larger than the peg holes, so as to prevent the removable peg from being inserted past the shoulder. In use, the shoulder is frictionally retained within one peg hole, and the shaft is slidably disposed within the other peg hole wherein the shaft can move inwardly and outwardly within the other peg hole so as to permit the small compression-adjusting ends to move inwardly and outwardly relative to each other.  
         [0075]    The small biassing device  220  has small sidewalls  222 , a small proximal end wall  224 , distal end ridges  226 , a thin spacer  228 , a thick spacer  230 , small retainer ridges  232  and a peg slot  234 . The thin spacer  228  has two oppositely-disposed outward-acing thin spacer bearing surfaces  236 . The thick spacer  230  has two oppositely-disposed outward-facing thick spacer bearing surfaces  238 . In use, the peg  204  is disposed within the peg slot  234 ; and the small biassing device  220  is positioned so that the small compression-adjusting ends  200  abut either the thin spacer bearing surfaces  236  if the user desires lesser compressive force between the jaw surfaces  72 , or the thick spacer bearing surfaces  238  if the user desires greater compressive force between the jaw surfaces  72 .  
         [0076]    The small sidewalls  222  and small proximal end wall  224  function to prevent relative movement between the small compression-adjusting ends  200  and the small biassing device  220  in much the same manner as the sidewalls  80  and proximal end wall  82  with respect to the compression-adjusting ends  20  and the biassing device  18 . However, the distal end ridge  226  is different from the distal end wall  84  in that it plays little role in preventing the small biassing device  220  from moving proximally relative to the small compression-adjusting ends  200 , because the distal end ridges  226  project outward relative to the thick spacer bearing surfaces  238 , no more than do the small retainer ridges  232 . When the small compression-adjusting ends  200  are abutting the thick spacer bearing surfaces  238 , proximal movement of the small biassing device  220  relative to the small compression-adjusting ends  220  is prevented by the peg  204  abutting the distal end of the peg slot  234 . In this way, the small biassing device  220  is prevented from slipping proximally off the small compression-adjusting ends  200  when the small biassing device  220  is being adjusted from the position where the small compression-adjusting ends  200  abut against the thin spacer bearing surfaces  236  to where the small compression-adjusting ends  200  abut the thick spacer bearing surfaces  238 .  
         [0077]    Empirical information obtained from downrigger fishing indicates that a desirable range of release tensions (as measured by hanging the line clamp  10  from a leader line, clamping a loop of fishing line between the jaw surfaces  72  and adding weight to the loop of fishing line until the fishing line is released by the line clamp  10 ) is from 0.25 lb. to 17.5 lb. This range is dependent on, among other things, the fish being sought and the size of fishing line. It has been found that two different sizes of line clamp  10  of the present design will cover this desired range, one providing a range of 0.25 lb. To 2.5 lb. and the other providing a range of 3 lb. to 17.5 lb. The overall design of the line clamp  10 , including the thickness of the spacers  86 , the resiliency of the arms  12 , the thickness of the stiffener  38 , the length of the jaw surfaces  72  and the material from which the jacket  14  is made, should reflect these empirically-preferred release tensions.  
         [0078]    The foregoing is a description of preferred embodiments of the invention which is given by way of example. The invention is not to be taken as limited to any of the specific features as described, but comprehends all such variations thereof as come within the scope of the appended claims.