Description

The present invention relates to a safety clamp for use in a fall arrest system for protecting workmen operating at elevated positions.

Workmen who need to gain access to elevated areas local to potential fall hazards are generally required by health and safety regulations to be equipped with an appropriate safety system such as a fall restraint or fall arrest system so that in the event of a slip or fall potential injury or fatality can be prevented. These systems typically involve the workman wearing a harness attached via a lanyard and a safety clamp to a safety rail mounted on a building. The safety rail comprises a rigid cable or rod having two opposing ends that are secured by end anchors to a building. The safety rail may be positioned horizontally or vertically to a roof or a wall, respectively, and it may also be further supported by intermediate anchors. Fall arrest systems enable the workman to move relatively unrestrained because as the workman moves the lanyard pulls on the clamp such that the clamp freely slides along the rail over any intermediate anchors.

Known safety clamps are configured such that to attach the safety clamp to a safety rail, either of the two ends of the safety rail is fed through a passage of the safety clamp. The passage is at least partially enclosing the safety rail and so enables the safety clamp to slide along the safety rail without accidentally detaching. The safety clamp is removed from the safety rail at either ends of the safety rail, by withdrawing the safety rail out of the passage of the safety clamp. Therefore, known safety clamps can only be attached and removed at either ends of the safety rail, which may cause inconvenience to a user who needs to move between fall arrest systems prior to reaching the end of the safety rail.

The present invention seeks to provide a safety clamp for use in such a fall arrest system that overcomes or substantially alleviates the problems mentioned above.

According to the present invention, there is provided a safety clamp for use in a fall arrest system, the safety clamp comprising, a body portion formed with a plate section having a plane, a plate portion having a plane, the body portion and the plate portion together define a passage for receiving a safety rail, the plate portion is pivotable relative to the body portion between, a first position wherein the plane of the plate portion is at an angle relative to the plane of the plate section such that the passage is open along its length to enable a safety rail to be inserted into, or removed from, the passage, at any location along the length of the safety rail, and a second position in which the plane of the plate portion is substantially parallel to the plane of the plate section such that a safety rail can be retained within the passage, wherein the safety clamp further comprises an actuating member that is at least partially located between the plate section and the plate portion, the actuating member being pivotally attached to the plate section of the body portion. In one embodiment, the plate portion is pivotable relative to the body portion and the actuating member.

The actuating member may be pivotally attached to the body portion only. The plate portion may be pivotally attached to the body portion only.

In one embodiment, the safety clamp further comprises biasing means configured to bias the plate portion into its first position. The body portion may be configured to prevent rotation of the body portion and the plate portion relative to each other until the actuating member is pivoted into a specific position.

Conveniently, the plate portion may comprise a cut out portion with which the actuating member aligns as it is pivoted into its specific position such that a portion of the actuating member is received in said cut out portion when the body and plate portions are rotated relative to each other.

In one embodiment, the actuating member comprises an aperture for attachment of a lanyard thereto, the body and/ or plate portion being configured such that the actuating member cannot be rotated into its specific position when a lanyard is attached to the actuating member through the aperture.

The body and/or plate portion may extend over the aperture of the actuating member when the actuating member is in its specific position such that rotation of the actuating member into its specific position is blocked by said plate and/or body portion when a lanyard is coupled to the actuating member via the aperture.

In one embodiment, the safety clamp may further comprise a rolling system engaging with a safety rail received in the passage during use.

The rolling system may be configured to retain the safety clamp in its position about the safety rail as the safety clamp travels along a safety rail. The rolling system may be movable between a first position wherein it engages a safety rail and a second position wherein it is moved away from the safety rail.

In one embodiment, the rolling system is movable between its positions in response to rotation of the actuating member.

The actuating member may be rotatable between a resting position and a specific position, and as the actuating member rotates from the resting position to the specific position the rolling system moves from its first position to its second position.

According to another aspect of the invention there is provided a safety clamp for use in a fall arrest system, the safety clamp comprising a body portion, a plate portion, the body portion and the plate portion together define a passage for receiving a safety rail, the plate portion is moveable relative to the body portion between a first position such that the passage is open along its length to enable a safety rail to be inserted into, or removed from, the passage, at any location along the length of the safety rail, and a second position wherein a safety rail can be retained within the passage, biasing means biasing the plate portion towards its first position, wherein the safety clamp further comprises an actuating member that is pivotable relative to the body portion and the plate portion, and upon the actuating member pivoting into a specific position the plate portion is biased from its second position into its first position.

The safety clamp may comprise any of the features claimed in claims 2 to 5 and 7 to 14. According to yet another aspect of the invention, there is provided a safety clamp for use in a fall arrest system having a safety rail, the safety clamp comprising a body portion, a plate portion, together defining a passage for receiving a safety rail such that the safety clamp can travel along the safety rail, a rolling system engaging a safety rail received in the passage during use, the rolling system being configured so as to retain the safety clamp in its position about the safety rail as the clamp travels along a safety rail.

In one embodiment, the rolling system may be movable between a first position wherein it engages a safety rail and a second position wherein it is moved away from the safety rail.

The rolling system may comprise a roller arm having two ends, one end being pivotally attached to the body portion and the other end having a roller configured to engage with a safety rail.

The safety clamp may further comprise an actuating member and the rolling system is movable between its positions in response to rotation of the actuating member.

In one embodiment, the actuating member may be rotatable between a resting position and a specific position, and as the actuating member rotates from its resting position to its specific position the rolling system moves from its first position to its second position.

The actuating member may be formed with a protrusion that engages the roller arm as the actuating member is rotated.

The safety clamp may further comprise any of the features claimed in claims 6 to 9.

Embodiments of the present invention will now be described by way of example only, with reference to the accompanying drawings, in which;

Figure 1 shows a perspective view of a safety clamp according to an embodiment of the present invention;

Figure 2 shows a perspective view of a body portion of the safety clamp shown in figure Figure 3 shows a perspective view of the safety clamp in figure 1 without a plate portion;

Figure 4 shows a perspective view of the safety clamp in figure 1 wherein the plate portion is in a first position;

Figure 5 shows a cross-sectional view of the safety clamp in figure 1, wherein an actuating member is in an engaged position;

Figure 6 shows a planar front view of the safety clamp in figure 1 without a plate portion, wherein the actuating member is in a specific position; and

Figure 7 shows an exploded view of the safety clamp.

Referring now to Figures 1 and 7, a safety clamp 1 of a first exemplary embodiment is shown comprising a body portion 2, a plate portion 3 defining a first passage 4 for receiving a horizontal and/or vertical safety rail. The portions 2, 3 are moveable relative to each other between an open position (first position) and a closed position (second position) so that a safety rail can be received in the passage 4 or be removed from the passage 4 at any point along the length of a safety rail as will become apparent from the description below.

It should be understood that the term 'vertical' used herein with reference to a safety rail or a safety rail section includes any safety rail that is formed at an angle relative to a horizontal plane. Furthermore, it should be understood that the term "safety rail" used herein may be a rod or cable, or any other means suitable for being received in the passage 4 of the safety clamp 1. Referring now to figure 2, the body portion 2 comprises a plate section 5 and a hooked portion 7 extending from the plate section 5. The hooked portion 7 is formed by an end of the body portion 2 being folded back on itself. The hooked portion 7 partially defines the passage 4 of the safety clamp 1. The passage 4 comprises a longitudinal axis Ά'. The edges 4a, 4b of the opposing ends of the passage are bevelled or chamfered so that the safety clamp 1 can easily travel across a curved safety rail. An edge 8 of the body portion 2 opposite the hooked portion 7, has a non-linear profile wherein a raised section 9 of the edge 8 extends relative to the remainder of the edge 8.

The body portion 2 further comprises a first and a second hinge hole 11, 12. The first hinge hole 11 is for receiving an axle pin 32 about which an actuating member 24 rotates, and the second hinge hole 12 is for rotatably attaching a roller system 41 to the body portion 2.

A first elongate spring recess 13 extends from the first hinge hole 11 towards the raised section 9 of edge 8 of the plate section 5. The first elongate spring recess 13 extends on an inner surface of the body portion 2. The first elongate spring recess 13 is configured to receive an arm of a torsion spring 36 interacting with the actuating member 24.

A second elongate spring recess 14 extends from the second hinge hole 12 towards the centre of the inner surface of body portion 2 such that the longitudinal axis of the first elongate spring recess 13 is transverse to the longitudinal axis of the second elongate spring recess 14. The second elongate spring recess 14 is configured to receive an arm of a torsion spring 47 interacting with the roller system 41. The body portion 2 further comprises two pairs of holes 16 for securing two hinge blocks 17, 18 to the body portion 2. The hinge blocks 17, 18 may be secured to the body portion 2 by screws 19 or other means passing through the two pairs of holes 16 and into corresponding holes formed in the hinge blocks 17, 18 as illustrated in figure 7. Adjacent to each pair of holes 16 formed on the plate section 5 of the body portion 2, is a guiding recess 21 for receiving pins extending from the hinge blocks 17, 18 such that during assembly of the safety clamp 1 the hinge blocks can be slid into position and thereafter secured to the body portion 2 by screws 19.

Referring now to figure 1 and 4, the plate portion 3 has an overall shape of a plate and is configured to pivot relative to the body portion 2 between a first and a second position. In the first position, the plane of the plate portion 3 is at an angle relative to the plane of the plate section 5 such that the passage is open along its length to enable a safety rail to be inserted into, or removed from, the passage, at any location along the length of the safety rail (see figure 4). In the second position as seen in figure 1, the plane of the plate portion 3 is substantially parallel to the plane of the plate section 5 of the body portion 2, such that a safety rail can be retained within the passage. It should be understood that the second position is not limited to the plane of the plate portion 3 being parallel to the plane of the plate section 5 of the body portion 2, it also

encompasses the plane of the plate portion 3 being ±5°relative to the plane of the plate section 5 of the body portion 2. The plate portion 3 has a lower edge 22 which together with the hooked portion 7 of the body portion 2 defines the passage 4 configured to receive a safety rail. The opposing upper edge 23 of the plate portion 3 has a non-linear profile wherein it comprises a raised curved section 20 and a lower section or a cut-out portion 25. The cut out portion25 is aligned with the raised section 9 of the edge 8 opposite the hooked portion 7 as can best be appreciated in figure 4. This enables for the actuating member 24 to be received in the cut out portion25 as explained in more detail below. The plate portion 3 comprises opposing side walls 26 each formed with a pin receiving hole 26a as seen in figure 4. A pin 27 is inserted through the hole of each side wall 26 and into

corresponding holes 28 formed on the hinge blocks 17, 18 as seen in figure 7. A hinge spacer 27a may be located about the pin. The hinge blocks 17, 18 therefore act as attachment means for the plate portion 3 and this configuration enables the plate portion 3 to be hingedly attached to the body portion 2 whilst providing a space between the plate portion 3 and the body portion 2 for the actuating member 24 and other mechanical components that form part of the safety clamp 1.

It should be understood that in an alternative embodiment, the plate portion 3 is directly hingedly attached to the body portion 2. For example, the hinge blocks 17, 18 may be integrally formed with the body portion 2.

A torsion spring 51 locates about one or both of the pins 27 hingedly connecting the plate portion 3 to the hinge blocks 17, 18. The torsion spring 51 biases the plate portion 3 to rotate such that the plate portion is forced into its first position as illustrated in figure 4.

The internal mechanical components located between the body portion 2 and the plate portion 3 will now be described with reference to figures 3 and 7.

The safety clamp 1 comprises an actuating member 24 as described above. The actuating member 24 is located between the plate section 5 of the body portion 2 and the plate portion 3. The actuating member 24 is hingedly attached to the body portion 2 and rotates about a rotation axis transverse to the planes of the plate section 5 of the body portion 2 and the plate portion 3. The actuating member 24 comprises a bar 26 having an aperture 27 at one end for receiving a carabiner (not shown) which is connected to a user's harness via a lanyard, and a stopping portion 28 extending from an opposite end of the bar 26. The stopping portion 28 locates in the passage 4 and engages with a safety rail during use as explained in more detail below. The actuating member 24 is further formed with an axle hole 29 located at the opposite end to the aperture 27, adjacent to where the stopping portion extends. An axle pin 32 is passed through the axle hole 29 of the actuating member 24, the passage of the torsion spring 36 and the first hinge hole 11 of the body portion 2 such that the actuating member 24 is rotatably attached to the plate section 5 of the body portion 2. A spacer 36a may be sandwiched between the actuating member 24 and the torsion spring 36 as seen in figure 7. A cover 31 as illustrated in figure 7 may be secured to an outer surface of the body portion 2 such that it covers the first hinge hole 11 and the axle pin 32 received therein. The cover 31 may have an axle passage 33 as seen in figure 7 that locates in the first hinge hole 11 of the body portion 2, the passage of the torsion spring 36 and the axle hole 29 of the actuating member 24, such that the outer surface of the axle passage forms a bearing surface. The axle pin 32, in the form of a screw, is then screwed into the axle passage 33 thereby enabling the actuating member 24 to rotate relative to the body portion 2 and the plate portion 3 but preventing the actuating member 24 from disconnecting or coming off the axle passage 33.

The stopping portion 28 of the actuating member 24 comprises a braking surface 28a which is configured to face the passage 4 and engages with a safety rail when the actuating member is pulled to an engaged position, i.e. during a fall (see figure 5). The stopping portion 28 of the actuating member 24 further comprises a protrusion 34 located on the surface of the actuating member facing the plate portion 3. The protrusion 34 extends away from the actuating member 24 in a direction parallel to the rotational axis of the actuating member 24. The protrusion 34 engages the roller system 41 when the actuating member 24 is pulled to a specific position as seen in figure 4. This is explained in more detail below.

The bar 26 of the actuating member 24 is further provided with an elongate spring recess (not shown) which extends in the direction of the bar 26. The elongate spring recess receives a second arm of the torsion spring 36. The first arm of the torsion spring 36 locates in the first elongate spring recess 13 formed on the body portion 2 as described above. The actuating member 24 is therefore biased by the torsion spring 36 towards a resting or neutral position (i.e. when the user is at a standstill) in which the stopping portion 28 locates in the passage 4, and in use, the stopping portion 28 gently engages the safety rail, thereby preventing the safety clamp 1 from moving along the safety rail. The roller system 41 will now be described with reference to figures 3 and 7. The roller system 41 comprises a roller arm 42 having opposing ends. A first end is formed with a first hole 43 to which a roller 44 is rotatably attached with securing means 44a, 44b. The roller 44 attached to the roller arm 42 may be a concave roller, however this is optional. The second opposing end is formed with second hole 45. An annular retainer 52 is received in the second hole 45 and a screw 53 is passed through the retainer 52 and into the passage of a tubular hinge support 46. This enables the roller arm 42 to be rotatably secured to the tubular hinge support 46 and for the retainer to provide a bearing surface about which the roller arm 42 can rotate. The opposite end of the tubular hinge support 46 to which the roller arm 42 is rotationally attached, is secured to the body portion 2 by a screw 51 locating in the second hinge hole 12 of the body portion 2 and the passage of the tubular hinge support 46. The torsion spring 47 is located about the tubular hinge support 46 between the roller arm 42 and the body portion 2. A first arm of the torsion spring locates in the second elongate spring recess 14 formed in the body portion 2, and a second arm of the torsion spring 47 locates in a corresponding elongate recess (not shown) formed on a surface of the roller arm 42 facing the plate section 5 of the body portion 2. The torsion spring 47 biases the roller arm 42 towards a first position wherein the roller 44 is biased towards the passage 4. In use, when the actuating member 24 is in its engaged position (during a fall), disengaged position (when a user's lanyard pulls on the actuating member as they walk along a safety rail) or neutral position (when no force is exerted on the actuating member by the user, i.e. the user is still), the roller arm 42 is in its first position such that the roller 44 engages the safety rail. The roller arm 42 is moved towards a second position against the force of the torsion spring 47 when the actuating member 24 is pulled towards its specific position as described below. As the actuating member 24 moves towards its specific position, the protrusion 34 of the actuating member 24 engages with a lower surface 42a of the roller arm 42. The protrusion 34 engages the roller arm 42 such that the roller arm 42 rotates about an axis of the second hole 45 of the roller arm 42 in a plane parallel to the plane of the plate section 5 of the body portion 2 and the plate portion 3. This causes the roller 44 to move away from the safety rail up into the safety clamp 1 to its second position (see figure 4). As described above, the actuating member 24 and the roller system 41 are rotationally attached to the body portion 2, such that no internal components are attached to the plate portion 3. The plate portion 3 therefore covers and protects the internal components as well as partially defining the passage 4 in which the safety rail locates. This configuration makes the safety clamp more robust and rigid. It should be understood that although torsion springs 36, 47 and 51 have been described above, alternative biasing means can be used. Furthermore, the actuating member may be an actuating lever.

Operation of the safety clamp will now be described with reference to figures 1 to 7.

When a user is to attach the safety clamp 1 to a vertical or horizontal safety rail, he can do so at any point along the length of the safety rail 1 as the passage 4 of the safety clamp 1 is configured to open up along its length. To open the safety clamp 1, a user pulls the actuating member 24 against the biasing force of the torsion spring 36 such that the actuating member aligns with the cut out portion 25 of the plate portion 3. The actuating member 25 is now in its specific position, which allows for the plate portion 3 to be pivoted relative to the body portion 2 such that the actuating member 24 locates in the cut out portion 25 of the plate portion 3 as best seen in figure 4. It should be understood that when the actuating member 24 is in any other position, such as neutral, engaged or disengaged position, it prevents the plate portion 3 to pivot relative to the body portion 2 into an open position.

Furthermore, when a lanyard or carabiner is attached to the aperture 27 of the actuating member 24 the raised section 9 of the edge of the body portion 2 extends over the aperture 27 of the actuating member 24 such that it blocks the rotation of the actuating member 24 into its specific position. In an alternative embodiment, the plate portion 3 is configured to extend over the aperture 27 of the actuating member 24 rather than the raised section 9 of the body portion 2 so as to block rotation of the actuating member 24 into its specific position.

When the actuating member 24 locates in the cut out portion 25 of the plate portion 3, the biasing force of the torsion spring 51 biases the plate portion 3 into its first position. In this position, the passage 4 is open along its length (see figure 4) so that a vertical or horizontal safety rail can locate therein. Furthermore, as the actuating member 24 rotates towards its specific position, the stopping portion 28 is withdrawn from the passage 4 as seen in figure 4 such that a safety rail can easily locate in the passage. Moreover, the rotation of the actuating member 24 towards its specific position, causes its protrusion 34 to engage with the lower surface 42a of the roller arm 42 such that the roller arm 42 rotates about the axis of the second hole 45 in a direction so that the roller 44 is withdrawn from the passage, i.e. the roller 44 rotates from a first position to a second position. The passage 4 is now clear and a vertical or horizontal safety rail can easily be located therein.

When a vertical or horizontal safety rail has located in the passage 4, the user lets the actuating member 24 rotate towards its neutral position under the biasing force of the torsion spring 36 as they also push the plate portion 3 against the biasing force of torsion spring 51 to its second position (closed position) wherein the safety rail is retained within the passage 4 (see figure 1).

Thereafter, the user attaches its lanyard or carabiner to the aperture 27 of the actuating member 24.

When the user is at a standstill, such that the lanyard does not pull on the actuating member 24, the actuating member 24 is in its neutral position in which the stopping portion 28 gently engages the vertical or horizontal safety rail, thereby preventing the safety clamp 1 from moving along the safety rail. The roller 44 of the rolling system is biased against the safety rail, thus it limits the rotational movement of the safety clamp about the safety rail. This provides the advantage that the lanyard does not get wrapped around the safety rail and it makes the safety clamp 1 more manoeuvrable. When a user starts walking along the vertical or horizontal safety rail, the lanyard pulls on the actuating member 24 such that the actuating member 24 rotates to its disengaged position wherein the stopping portion 28 is drawn away from the safety rail, however the roller 44 of the roller system 41 still engages the safety rail. The safety clamp 1 can now freely travel along the safety rail as its position about the safety rail is maintained due to the roller 44 engaging the safety rail. Thus, also as the user walks along a vertical or horizontal safety rail, the rotational movement of the safety clamp about the safety rail is limited. This provides the advantage that the lanyard does not get wrapped around the safety rail and it makes the safety clamp 1 more manoeuvrable. In order to detach the safety clamp l from a safety rail, a user can do so at any point along the length of the safety rail by moving the plate portion 3 to its first position (open position) as described above. When the safety clamp 1 is attached to a horizontal safety rail, and a user falls, the clamp and the lanyard catches the user as they are falling, thereby preventing the user from injury or fatality.

When the safety clamp is on a vertical safety rail and a downward load is applied to the actuating member 24 due to the weight of a user who has fallen, the actuating member 24 rotates relative to the body portion 2 and the plate portion 3 about its rotational axis and the axle pin 32. The actuating member 24 rotates towards its engaged position in which the stopping portion 28 further engages the vertical safety rail thereby preventing any downward movement of the safety clamp 1 along the vertical safety rail. (The engaged position is best seen in figure 5.) Therefore, a fall of a user along a vertical safety rail will be arrested.

Although embodiments of the invention have been shown and described, it will be appreciated by those skilled in the art that variations may be made to the above exemplary embodiments that lie within the scope of the invention, as defined in the following claims.