The present invention relates to a strap tensioner of the type with a pivot arm serving as a handle which is pivotably mounted via one end in a frame serving as a guideway for the strap intended for tightening, the pivot arm having two deflection surfaces located at mutually different distances from the fulcrum of the pivot arm and over which the strap intended to be tensioned is designed to be laid, running in a single thickness over the first deflection surface which is located at the greater dis- tance from the fulcrum of the arm, and running double over the second deflection surface, in such a way that the sec¬ tions of the strap which are laid over the said second deflection surface are able to move relative to each other in a first position, the "releasing position", of the pivot arm in which the amount of bending of the strap over this surface is relatively small, and are prevented from moving relative to each other by a clamping effect between the sections of the strap in a second position, the "lock¬ ing position", of the pivot arm in which the corresponding amount of bending of the strap is relatively large, v/hile the strap is tightened as the pivot arm is moved from the releasing position towards the locking position.

The main object of the invention is to provide a strap tensioner of the above-mentioned kind which is able to bring relatively high levels of traction force to bear on the strap intended to be tensioned, both during tighten¬ ing and in the locked state, without this strap being sub¬ jected to wear due to mechanical action between the en- sioning arrangement and the strap. This object is achieved with the subject of the in¬ vention which is essentially characterised in that the frame has a check past which there runs the tensionable strap section of the strap in question which co-acts with the pivot arm, and a clamping device which extends across

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the frame and moves the plane of the strap, and which is designed to clamp the strap securely against the check in one position, the "clamping position", and to allow the strap to pass freely between the clamping device and the check in another position, the "free position", the clamp¬ ing device being designed to be moved by the pivot arm into its free position when the pivot arm is pivoted into its locking position, and having a catch which holds it in the free position when the pivot arm is moved back again towards its releasing position.

The invention is described in the following with reference to the accompanying drawings, on which

Figure 1 is a plan view showing a strap tensioner constructed according to the invention with a strap tightened by it, looking at right-angles to the plane of the strap,

Figure 2 is a vie-/ looking in the direction of the arrow II in Figure , showing he strap tensioner without a strap, Figure 3 is a longitudinal section through the ten¬ sioner shown in Figure ,

Figure 4- is a longitudinal section corresponding to Figure 3 through the tensioner, in a different position than in Figure 3, Figure 5 is a plan view of another embodiment of a strap tensioner, shown without a strap,

Figure δ is a longitudinal cross-section correspond¬ ing to Figure 3 through the strap ^" tensioner shown in Figure 5, Figure 7 s a detail from Figure , and

Figure 8 is the same detail viewed from the left as shown in Figure 7- .

The strap tensioner shown in Figures 1 - 3 consists of a pivot arm 1 serving as a handle, and aframe 2 in which the pivot arm is pivotably mounted by means of an axle 3. The frame 2 is constructed as a channel with a

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U-shaped cross-section, the side-cheeks of which are desig¬ nated -V on the drawings and the web of which, connecting the side-cheeks to each other is designated 5 and 6 res¬ pectively, i.e-. the web is divided into a front part 5 and a rear part 6 which are separated from each other by an opening 7« 2 e front web part 5 is provided at the rear with a protective edging 8 around which a strap 9 is laid. The strap 9 extends singly over a pin 10 extend¬ ing in the transverse direction thereof between the side- cheeks , and double over the edging 8, the taut strap lying at the very front and the free end section 9a of the strap lying nearest the edging and consequently being held clamped against the latter when the strap 9 is taut. The clamping force is such that there can be no slipping between the two sections a and 9b of the strap when there is traction on the s ^~ rap, due to the fact that the looo of the strap expending through the opening undergoes a relatively sharp angular change as it passes in through the opening 7 towards the pin 10 which is displaced to- wards the front relative to the edge 7a of the opening. The pivot arm 1 is similarly constructed in the form of a channel with a U-shaped cross-secbion, the side-cheeks of which are designated 11, and the web connecting the side- cheeks to each other is designated ^2 and 3 respectively, i.'e. the front section of the web is designated 12 and its rear section is designated 13. The two web sections 12 and 13 are separated from each other by an opening -. The distance between the outer races of the side-cheeks 11 is less than the distance between the inner faces of the side-cheeks , i.e. the pivot arm is accommodated in the space between the side-cheeks - of the frame. The axle 3 extends out through holes which are positioned in the side-cheeks of the frame and is locked at the outer face of each of the side-sheeks by means of a locking ring 5 which can expediently be of the split-ring type. Moreover,

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the axle 3 bridges the distance between the side-cheeks

11 of the pivot arm and thus forms a deflection bar for the strap 16 intended for tensioning. The web section

12 forms a deflection bar for the said strap and is equipped at the rear with a protective edging 7 around which the strap is laid in a loop. The front edge 14a of the opening thus forms the rear deflection surface of the deflection bar, while the axle 3 forms a front de¬ flection surface 3a for the strap. The deflection sur- face 3a is located at a shorter distance from the fulcrum of the pivot arm than the deflection surface 14a. The strap 16 extends double over the deflection surface 3 and singly over the deflection surface 14a, i.e. it passes round the deflection bar 12 in the form of a loop. The free end section 16a of the strap 16 lies between the section 16b of the strap intended for tensioning and the deflection surface 5a. The pivot arm 1 can pivot between the "locking position" shown in Figure 3 and the "releas¬ ing position" shown in Figure 4. In the locking position " k deflection surface 14a is located so that it is dis¬ placed backwards relative to the direction in which the strao 16 runs in towards the deflection surface 3a, while the same deflection surface is located so that the de¬ flection angle of the strap over the deflection surface 5 is relatively small in the releasing position shown in

Figure 4, which means that the two strap sections ^6a and 6b can move relative to each other at the deflection sur¬ face 5a. 1.~ designates a manually; releasable snap lock provided to hold the pivot arm 1 fixed in its locking position (Figure 3)« The snap lock S consists of a lock¬ ing member 1 the end sections a and 1°b of which ex¬ tend out through openings in the side-cheeks 11 of the pivot arm. On the locking member a lateral stop 20 is arranged against which one end of a compression spring 21 rests, the other end of this spring resting against the inside of one of the side-cheeks of the pivot arm. lo

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guide the compression spring 21 a finger 22 projecting out from the stop 20 extends through it and the side- cheek 11 involved. The spring 21 strives to hold the ■ locking member 19 in the position shown in Figure 1, while it can be moved by manual pressure on a finger-grip sur¬ face 23 on the end section 19b in the direction of the arrow A into a second displacement position in which the spring 21.is compressed. The two end sections 9 and 19b have sloping surfaces 24 and 25 respectively which co-act with corresponding sloping surfaces 46 on the side- cheeks 4 of the frame. The sloping surfaces 46 continue on into a locking notch 47 into which the end section of the locking member can be snapped. Or. an axle 26 extend¬ ing between the side-cheeks 11 of the pivot arm a cla p- ing device 27 constructed as a two-armed lever rod is mounted; the front lever arm 7a of this is equipped with an end surface with friction serrations 28 and its rear lever arm 27b is equipped with a locking arrangement which consists of an arm 9 extending alongside the axle 26, from a pivot axis 30 adjacent to one side-cheek of the pivot arm 1 out through the other side-cheek 11 of the pivot arm and also the corresponding side-cheek 4 of the frame, with a manipulating end section a project¬ ing outside the latter cheek. Between the clamping mem- ber 27 and the locking arm 29 a compression spring 3 is nipped in; this strives to move the arm 2 ^Q into the posi¬ tion shown in Figure 2 in which it is engaged in a lock¬ ing notch 3 arranged in the side-cheek of the frame. The locking notch 32 is formed in an opening 33 in the side-cheek of the frame, one side edge 33a of the opening 33 continuing into a step to form the locking notch 32. The locking notch 3 is located so that the clamping mem¬ ber 27 is held in the position shown in Figure 3 _, when its locking arm 29 engages in the locking notch 32. Near to .one of the side-cheeks of the frame the axle 26 is en¬ circled by a leg spring, one leg 35 of which is engaged

in a cut-out 36 in one side-cheek 4 and the other leg 37 of which rests against an abutment surface 39 on the lock¬ ing member 27 and strives to move the latter from the position shown in Figure 3 into the pivot position shown in Figure 4 in which the locking member clamps the strap 16 against a check 38 in the form of a pressed-up section in the web 6. To provide an effective and constant grip round the hand grip 1 its rear section, shown on the right in the drawing, is made relatively wide with a rear end section 3 which is bent round. The free strap section 18a is threaded past the side of the locking member 27 facing away from the check 38.

The use of the strap tensioner will understood from the following: In the embodiment example shown the strap tensioner is used in conjunction with two straps 9 and 16 running in towards each other, but it can naturally also be fixed to an object via the front end section, in which case the strap 9 is not used. Similarly, the straps 9 and 16 can be one and the same strati which passes round an object which is to be held tightly. If, for example, a strap laid round an object is used, one end section 9 is ex¬ pediently threaded in through the opening 7, round the crossbar or deflection bar 10, past the protective edging 8 between the strap section 9b and the web section 5, and out of the strap tensioner. The strap thus lies singly round the deflection bar 10 and double around the deflec¬ tion edging 8. The other end 1 „_of the strap is threaded from the rear into the strap tensioner over the check 38, and is laid round the deflection edging 7 on the pivot arm 1 when the latter is pivoted up into the position shown in Figure 4. The strap is threaded further in be¬ tween the deflection bar 3 and the strap section 16b and on out on the upper side of the clamping device 7 _. from whence it extends freely out of the strap tensioner. With the pivot arm 1 in the pivoting position shown in

Figure 4 the two strap sections 16a and 16b can move re¬ lative to each other over the deflection surface 3a, since the deflection angle at this surface is relatively small and there is therefore no significant clamping 5 effect between the two sections of the strap. 3efore beginning to tighten the strap, the locking arm 29 of the clamping device is moved against the effect of the spring 1 out of engagement in the locking notch 52, so that the clamping device is caused to pivot into the -10 clamping position shown in Figure 4 by the effect of the spring 4; in this position it clamps the strap 16 securely against the check 58. Vhen the pivot arm 1 is pivoted in the clockwise direction as depicted in Figure 1 the deflection angle at the deflection surface 5a is in- - creased, thereby increasing the friction between the two sections of the strap. Due to the fact that the deflec¬ tion surface 14a is located a greater distance from the fulcrum of the pivot arm than the deflection surface 5a, the strap 16 is pulled in when the pivoting movement of 20 the pivot arm is continued in the direction towards the position shown in Figure 3. The pivot arm can be moved back and forth to pull the strap 1 ^' 6 in repeatedly and tighten it. V/hen the pivot arm is moved counter-clockwise the strap is held in place " j the clamping device 27 25 while the clamping device is loosened and allows the strap to pass when the pivot arm is pivoted clockwise. V/hen the desired degree of tension has been achieved the pivot arm 1 is pivoted right down- into..the locking position shown in Figure 5. At the completion of this pivoting 0 movement the sloping surfaces 46 on the side-cheeks and the sloping surfaces 24, 25 on the locking device 19 cause the locking device 19 to be displaced against the effect of the compression spring 21 until it reaches the locking notch 47 into which the locking device snaps under the 5 effect of the spring 21. At the end of this movement the side-cheeks 11 of the pivot arm also strike against

the clamping member 27 via their longitudinal edges 40 and pivot it clockwise into the position shown in Fig¬ ure 5 against the effect of the spring 34, whereupon the locking arm 29 slides along the edge surface 33a of the opening and drops into the locking notch 32.

When the strap is to be released the lock 19 is pressed in in the direction of the arrow A in Figure 1 against the effect of the compression spring 3 , thereb enabling the pivot arm to be pivoted freely in the dire tion of the position shown in Figure 4. Due to the fac that the locking arm 29 is engaged in the locking notch 32 the clamping member remains in the position in 'which the strap 18 is able to pass freely between the latter and the check 38. Preferably, the pivot arm ^ will be pivoted carefully towards the position shown in Figure so that the strap 16 runs out when the strap angle at the deflection surface 3a has become small enough for the friction between the strap sections to be less than the traction force on the strap 16. 3y manoeuvring the pivot arm appropriately a gentle release of the strap t sion can thus be effected, .hen the nivot arm has been pivoted into the position shown in Figure 4 and the str is no longer under tension the strap 18 can be pulled o of the strap tensioner without any hindrance. If it should be desired to retain some strap tension, the cla ing device 27 can be released in the above-mentioned wa so that it takes up the clamping position shown in Fig¬ ure 4 in which it holds the strap" ^~ securely b its eccen tric function, backed up by the force of the spring 34. Like the above-described strap tensioner, the stra tensioner shown in Figures 5 to -8 consists of a pivot arm 101, which is mounted pivotably in a frame 102 b means of a pivot axle 105. As in the previous example, the pivot axle 103 bridges the distance between the sid cheeks 111 of the pivot arm 0 . The frame 102 is agai in this case made in the form of a channel, the si e-ch

of which are designated 104 and the front web section of which is designated 105 and the rear web section of which is designated 106. On the pivot arm a deflection bar 112 is arranged which has a position relative to the deflection surface of the pivot axle 105 which corresponds to that in the previous example. Furthermore, the pivot arm 101 is held in the locking position shown in Figure 6 by means of sprung tongues 150 stamped out of its side-cheeks and having bent-out end sections 1 which snap into cut-outs 15 in the side-cheeks 104 of the frame. The sprung ton¬ gues 150 can be bent in towards each other against the effect of the inherent spring capacity of the material, into a position in which the hook-shaped end sections 5 thread out through the cut-outs 1 2 and the pivot arm can thus be pivoted counter-clockwise as shown in Figure 6.

Preferably, the locking hooks have bevelled lower edges so that they are automatically introduced to the inside of ^' the side-cheeks 104 of the frame v/hen the pivot arm 10 is moved into the oosition shown in Figure 6. As in the ore- vious example, a clamping device 127 is pivotably mounted on a transverse axle, being held pressed against a check formed by the rear wen section 106 on the frame, in the position shown in Figure 6, by means of a leg spring 134. In the cut-out in the clamping device 127 in which the spring 1 4 is inserted there is a protruberance which one of the spring legs 136 passes when the clamping device is pivoted counter-clockwise towards its free position by manual action against a finger 15-3 arranged on the clamp¬ ing device, the protruberance being passed by with a snap action and the clamping device thus being held in its free, position. In this case, the free strap section 116a ex¬ tends through the clamping device instead of over its upper face as in the previous embodiment example. Instead of describing every part of this strap tensioner which cor- responds to a part in the strap tensioner described above, similar parts have been given the same reference numerals

preceded by the numeral 1 of a hundred. Vhen the pivot arm 101 is lowered into the locking position shown in Figure 6 it strikes against the locking member 127 and forces this against the spring effect into its free posi- tion in which the locking member remains, as in the pre¬ vious example. When the pivot arm is released by press¬ ing the arms 150 of the locking springs together, the clamping member 127 remains in its free position and can be released manually for the transition into its clamping position b means of the finger 153.

The invention is not restricted to the embodiment des¬ cribed above and shown on the drawings, but its details can be modified within the scope of the following Patent Claims 'without going beyond the basic concept of the in- vention.

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