FR2517289A1 - LIFTING HOOK WITH SAFETY DEVICE - Google Patents

Abstract

1. Lifting hook with safety device, including a hook casing (1) the open buckle of which delimits an inside hooking space (E) and an end of which forms a yoke (1a) for the linking of a closing catch (2) designed for co-operating with the fastening organ of a lifting apparatus or of a hanging organ, the catch (2) supporting in a hinged manner a safety lever (4) elastically and pivotally urged, housed and retracted within the yoke (1a) of the hook casing in the closing position of the catch, the interlocking end (4g) of the lever co-operating with a stop in the hook casing, said lifting hook being characterized in that the interlocking end (4g) of the swivelling safety lever (4) is shaped for abutment against the stop (1e or 8) of the casing, formed on a side of the hooking inside space (E) and adjacent to this space as much as possible, the interlocking lever (4) being of the type in which the fulcrum or pivotal axis (5), placed on a projection (2e) of the catch, is located between the resisting force applied on to the interlocking end (4g) and the motive force applied by finger thrust onto the opposed end (4b) of the lever, externally to the hook casing, the elastic means (6, 7 or 9) having the purpose to bring back permanently the interlocking end of the lever in the locking position against the stop of the casing ; the contacting point of the interlocking end (4g) with the stop (1e) or (8) of the casing being situated at a distance (x) slightly ahead (on the side of the general axis) of the vertical axis passing through the pivotal axis (5) of the vertical while there is provided a comparatively large interval (y) between the linking pin (3) of the catch and the said contacting point, the relative disposition of the three aforesaid points, namely : the pivotal axis (5) of the lever, the linking pin (3) of the catch and the contacting point of the interlocking end (4g) with the stop (1e or 8) permitting to ensure the locking of the catch on the casing of the hook, even when an excessive stress is exerted from the inside space of the catch, while said catch can be released and opened by a voluntary pressure of the finger, without excessive stress on the lever which is free to escape from the stop of the casing.

Description

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  The subject of the invention is a lifting hook with

security.

  The subject of the invention relates in particular to the sector

  technical means and lifting and handling devices.

  Lifting hooks are known with safety means.

  especially of the type comprising a hook body whose bolt

  open clef delimits an interior hooking space and one of which

  end cap shape for the articulation of a latch latch

  ture equipped to cooperate with the fastening member of a hoist or a suspension member; the pawl articulately carrying a safety lever pushed elastically pivoted, housed and retracted into the yoke of the hook body, in the position of closing the pawl, the locking end

  lever cooperating with a stop in the hook body.

  The essential importance of safety in lifting and handling operations is also

accidents in these activities.

  According to the invention, it has been wished to ensure better than in the past, this safety with greater conveniences in the maneuvers of the hook and the safety means In particular, it has been desired to obtain in a much more secure manner the locking of the latch and locking the picking space in the

  periods of maneuver We also wanted to facilitate the handling

  locking and unlocking the pawl.

  For this purpose, the lifting hook and a safety device

  according to the invention are remarkable in that the locking end of the safety swivel lever is profiled for taking

  support against the abutment of the body formed of the c 8 t of the space ind

  the hooking lever and as close as possible to this space, the locking lever being of the type whose fulcrum or pivot axis on a protruding portion of the pawl is between the resistant force applied to the locking end, and the driving force applied by digital push at the opposite end

  lever, on the outside of the hook body, the elastic means

  acting in such a way as to constantly bring back the end of ver-

  locking the lever in the locking position against the abutment of the body E

  the relative disposition of the three important points:

  the latch, pivot axis of the locking lever and contact portion between the stop and the locking end, being such that more abnormal opening force of the pawl s _ _ _ _ _ _ exerts in the safety stop position, and more the locking of the lever to the lever, while a voluntary digital pressure levie L releases, without undue effort, the pawl that 1 can be opened. These and other characteristics will emerge from the

description which follows.

  To fix the object of the invention, without however limiting it, in the accompanying drawings: FIG. 1 is a partial sectional view of the hook according to

  an embodiment illustrated by way of example and

tee in the closed position.

  FIG. 2 is a sectional view taken along the line

2-2 of Figure 1.

  FIG. 3 is a sectional view taken along the line 3-3 of FIG. 1, showing the locking between the body of the

hook and pawl.

  Figures 4 and 5 are partial plan views showing two embodiments of the safety lever and the return spring. FIG. 6 is a section taken along the line 6-6 of FIG. 5, showing the shape of the gripping end of the

safety lever.

  Figure 7 is a partial sectional view on a larger scale.

  the, illustrating the safety position at the opening.

  Figure 8 is a partial sectional view on a larger scale.

  illustrating the opening position of the hook before passage of

opening security.

  Figure 9 is a partial view showing a variant of

  simplified realization of the closure of the hook.

  FIG. 10 is a partial sectional view illustrating an alternative embodiment of the safety device, in particular

  of the return spring in the locking position.

  Figure II is a partial sectional view illustrating a

  variant of the stop in the body of the hook.

  In order to render the object of the invention more concrete, it is now described in non-limiting embodiments.

  illustrated in the figures of the drawings.

  The hook according to the in ention comprises a hook body (1) of robust section, with an end (la) forming a yoke for articulation with the pawl (2) via an axis (3) -3 - riveted or otherwise mounted The hook body forms a loop

  open delimiting a space (E) for picking.

  The pawl (2) has above its orifice (2 a D of

  culation to the body, an ovalized eye or any other useful form (stem, swivel), for the attachment of the suspension target, and above said articulation, a form (2b) complementary to the body of

  hook, to form together a closed ring.

  The closure of this ring can be effected by any means. For example, as shown in FIG. 9, simply perform the ends of the body and the bevel-shaped pawl (1b and 2c), or else constitute a point of contact. hooking or locking by engaging the end (2 d) forming the latch of the pawl in a constricted portion (lc) of the end of the body, as shown in Figures 1 and 3 Of course, the yoke (2 d) and the throat (Ic)

  are appropriately oriented according to the trajectory of the

  watch between the open position and the closed position.

  The safety device comprises a lever (4) articulated on a clevis (2 e) of the pawl via an axis (5) of the type

mechanindus pin or the like.

  The lever is completely contained inside the yoke (la) of the hook body in the locked position, so that it can not be hooked involuntarily during lifting and handling operations. Moreover, it is oriented towards the space

  inside (E) of the hook body, so with a very

  compared to the screed (la), which increases the length of

  lever arm without unduly increasing the length of the hook. The lever (4) has a narrow portion (4a) arranged to

  pass between the branches of the clevis (2 c) of the pawl, and a

  raised and bent (4b), of greater width, to

  to kill a pallet of support for the thumb of the manipulator (figures

4 and 5).

  Note that the pallet (4b) has a section facilitating the support

  for example, and as shown in Figure 6, the sec-

  It may be rectangular with side beads (4c).

  The pawl (2) has at the elbow (4 d) lever,

  a notch (2 f) in an arc of a circle concentric to the axis of articulation

  lation (3) and ended with circular sectors (2 g 2 h) defined

  setting limit stops for a protrusion (Id) formed

  in the clevis (la) of the body, directly from the construction or

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niere reported (pin, finger).

  The lever (4) is held constantly pressed against the notch (2 f) of the latch, at its elbow (4 d), by

  least an elastic means suitably arranged.

  FIG. 4 shows an exemplary embodiment of this elastic return. In this embodiment, the axis (5) on each side of the narrow portion (4 a) of the lever and between the clevis legs is hoisted. (2 a), a spiral spring (b) of which one bent end (6 a) rests on the lever, while the other

  end (Db) rests under tension under the pawl (2).

  In Figure 5, there is illustrated another embodiment in the-

  which the narrow part (4 a) of the lever form clevis to house a

  spring (7) spirally wound on the shaft (5).

  Said spring also has a bent end (7 a) of support on the lever, while the other end (7 b) is supported by

tension under the pawl (2).

  In Figure 10, there is illustrated another provision of the

  In this example, we can see that the spring (9)

  rolled on the shaft (5) has one leg (9a) bearing in front of the lever, that is to say opposite the pawl, while the other leg (9b)

  extends in support in the bottom of the yoke (the) of the hook body.

  Importantly, the locking end (4 g)

  of the lever, directed towards the interior hooking space (E),

  a surface or ramp in sector of a circle having as a center

  the pivot axis (5) of the lever A locking stop di-

  rectally formed in the bottom of the screed (reference (the), figures 1, 7, 8, 10) or reported in the form of a finger or pin (reference 8, FIG. 11), is arranged as close as possible to the space ( E) picking, that is to say with a dimension or thickness (e),

  minimum and sufficient material to ensure the necessary resistance

  necessary for the blocking effect in the event of abnormal efforts on the

  watch tending to produce the inadvertent opening of said lingueto

  To this end, it should be noted that the contact point of the former

  locking end '4 g) with the stop (or S) of the body, is located at a distance (x) a little forward (on the side of the general axis), the vertical axis passing through the axis pivoting (5) of the lever, underneath a relatively large gap (y)

  between the axis (3) and the point of contact between (4 g) and (the or $ 8.

  It will be understood that this relative arrangement of the three aforementioned points, namely: the axis (5) this pivoting of the lever, the axis (3) -5 _ of articulation of the latch and the point of contact of the end

  locking with the stop (the or 8), ensures the blocking

  cage of the pawl on the hook hook me soul when an abnormal force exerted from the interior space on the pawl, while said pawl can be released and opened by a voluntary digital pressure without abnormal effort on the lever that

  can escape the abutment of the body.

  Note that the pivot axis (5) of the lever is

  between the resisting force applied to the

  rust (4 g) and the driving force applied by digital pushing

  on the pallet (4b), with a significant leverage in that

  that the axis (5) is at a distance (dl) from the lock end

  (4 g) much shorter than the distance (d 2) between this

  axis and point of application of the driving force (Figure 8).

  On the other hand, the axis (3) of articulation of the pawl is located above the axis (5) of pivoting of the lever (4), relative to the space (E) of pickings The narrow part (4 a) of the ramp lever, rests against the projection (id) arranged in the yoke of the hook body,

  during the entire opening maneuver

  combined with the support of the elbow (4 d) of the lever against the

  size (2 f) of the latch in the closed position, avoids any

  thumb in the case where the manipulator lets out the lever during opening, before the elbow (4 d) of the lever n '

  reach the projection (1 d), as seen in Figure 8.

  The pawl pushed by the combined action of the spring (6, 7, or 9) and the manual thrust, continues its movement, while the pallet (4b) of the lever is slid against the protrusion

  (Id) The maximum opening is reached when the elbow (4 d) of the

  to rest against the notch (2 f) of the latch in front of

  the projection (Id) At this moment, the lever (4) -bute both

  be the notch (2 f) and against the projection (Id), which keeps the hook in the open position when the

release (Figure 7).

  To return the pawl (2) to the closed position, illus-

  trée figure 1, it suffices that the hook is under tension, that is,

  that is to say that a pulling force is exerted on the pawl by 1 lifting gear The pawl pivots in the closed position as soon as the lifting force is greater than the force of the spring, and the lever (4) then slides on the projection (Id) At the end of the race,

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  the lever is then again abutted by its elbow (4 d) against the notch (2 f) of the iinguct to the upper part, and butee npar its convex face r Ig) ccntre the support face ie} or the finger

reported (-).

  The benefits are apparent from the description,

  Moreover, safety is reinforced by the fact that the pivot axis of the lever is very close to the latching end of the latch.

  which has the effect of accentuating the blockage when the strength of the

increase,

  the quick and convenient gripping of the lever in a natural gesture

  rel o the hand grips the body of the hook while the thumb acts on the lever, which allows the manipulator to hold the other free hand, the slings or other means of suspension of the load, the housing of the lever in the body the hook avoiding any risk of untimely clinging, and its mounting inclined in the yoke to increase the length of the lever arm by

a given hook width.

  The invention is in no way limited to that of its modes of application nor to those of the embodiments of its various parts which have more especially been indicated; she

  on the contrary, embraces all variants.

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Claims (2)

  -1 Lifting hook with safety device, comprising a hook body (1) whose open mouth defines an inner space (E) for ratcheting and one end of which forms a clevis (la) for the articulation of a pawl (2) ) for cooperating with the attaching device of a hoist or a suspension member, the latch (2) hingedly supporting a safety lever (4) elastically pushed to pivot, housed and retracted into the yoke (1a) of the hook body in position l of closing the pawl, the locking end (4g) of the lever O 10 cooperating with an abutment in the hook body, characterized in that the locking end (4 g) of the lever (4) pivoting safety (4) is profiled to bear against the stop (the   or 8) of the body, formed on the side of the inner space (E) of cro-   and as close as possible to this space, the lever of ver-   rust (4) being of the type whose fulcrum or pivot axis   (5) on a protruding part (2 e) of the pawl, is between the resisting force applied to the locking end (4 g), and the driving force applied by digital pushing to the opposite end (4 b). the lever, the outer body of the body   hook, the elastic means (6, 7 or 9) acting in such a way as to   constantly the locking end of the lever in the locking position against the stop of the body; the relative arrangement of the three important points: axis (3) of pivoting of the pawl, axis (5) of pivoting of the locking lever and contact portion between the stop (the or 8) and the locking end (4 g), being such that more abnormal opening force of the pawl is exerted in the safety stop position, and the locking of the lever increases, while a voluntary digital pressure on the lever releases, without undue effort, the pawl that can be open.   The lifting hook according to claim 1, comprising a   stop (the or 8) in the hook body for the lever of ver-   rusting (4), characterized in that the thickness (e) of the abutment (the or 8) of the hook body against which the locking end (4 g) bears and which is as close as possible to the internal space (E) picking, is limited to the minimum dimension and sufficient to provide the necessary resistance to the locking effect in case of abnormal efforts on the pawl tending to   1 or ur ur in-tempest Ive said latch.   Ratchet according to Claim 1, characterized in that the point of contact between the locking end (4 g) and the abutment (1) of the body is at a distance (x ) of the pivot axis (J 5) of the lever Lt very substantially lower than the istance (y) between this point and the general axis passing through the axis (3); said point of contact being disposed between these two axes.   -4 Lifting hook according to claim 1, characterized in that the locking end (4 g) of the lever has a profile in the form of a ramp or an arc having the center ltax (b) of by the lever.   Lifting hook according to claims 1 and 2 together,   characterized in that the locking abutment on the hook body (1) is constituted by a projection (1c) executed in the fondc & the screed (la).   Lifting hook according to claims 1 and 2 together,   characterized in that the locking abutment on the hook body (1) is constituted by an insert (8) of the type finger or pin.   Lifting hook according to claim 1, characterized in that the resilient biasing means of the lever (4) in the locking position against the abutment of the body (or 8) is constituted by at least one spring (6). or 7) wound on the axis (5) of pivoting of the lever and one branch (6b or 7b) bears against the underside of the pawl, while the other branch ('a or 7a) s' press the   face of the lever facing the pawl.   -8 lifting hook according to claim 1, characterized in that the resilient biasing means of the lever (4) in the locking position against the abutment of the body (or 8), is constituted by at least one spring (9) wound on the axis (5) of pivoting of the lever and one branch (9b, is supported on the bottom of the yoke (la) of the hook body, while the other branch (9 a) is under the lever, that is to say on the face opposite the bottom of the clevis.   -9- -9 Lifting hook according to claim 1, characterized in that the pawl (2) has on the side of the lever I security (4) a notch (2 f) in an arc concentric to the axis (3) articulation of the pawl, with ends (2 g, 2 h) forming limit stops against a protrusion (Id) executed   directly or as reported in the body coping.   Lifting hook according to claims 1 and 9 together   ble, characterized in that the internal profiled shape of the safety lever (4) and the position of the projection (Id) of the clevis of the   body, allow the lever to be supported during the maneuver   verture, thus avoiding the jamming of a finger between the sink and the pawl.   Lifting hook according to claims 1, 9 and 10   together characterized in that the open position duliinuet (2)   relative to the hook body (1), is provided by   bend of the elbow (4 d) of the safety lever (4) that the notch (2 f) of the latch and the end of gripping and pushing (4 b)   said lever against the protrusion (Id) of the body yoke.   -12 Lifting hook according to claim 1, characterized in that the gripping portion and push (4 b) of the lever And wider than the portion (4 a) of articulation and locking, and has a cross section with side bead to facilitate the support of the thumb.   -13 Lifting hook according to claim 1, characterized in that the very inclined and close to the vertical position of the lever (4) in the locking position, that with respect to the width of the yoke (la) of the body, allows the realization of a lever with a large lever arm, while maintaining a suitable useful width of the hook body, and ensuring 1 ' retraction of the lever in the clevis.