The present invention is related to a safety pin lock system for quick coupler used in construction equipment.

In the conventional technology of excavators, quick coupler is mounted at the end of arm and grapples an attachment. It has a hook on front side and hydraulic actuating wedges on rear side. When the rear side wedge is not engaged properly, the quick coupler can drop the attachment and it is very dangerous. By locking the front pin when the rear wedge is extended, dropping an attachment accident can be prevented.

US Pat. Pub. No. 2014/0294497 A1 discloses a quick coupler for holding an implement which includes a frame having first and second plates. The quick coupler includes a locking system adapted to lock the implement in the first and second plates. The locking system includes securing latch member and hydraulic actuator connected to the latch member which is configured to move along a guide between the first and second plates. The locking system also includes a set of grooves provided on the securing latch member and a guide. The set of grooves are adapted to lock the securing latch member in a latched position. However, in case of power-off, the quick coupler stops working. Also there is no emergency release mechanism whenever something go wrong and quick release is needed. AU 2013 205 373 Al discloses a similar quick coupler.

This invention is to improve the shortcomings listed above.

The invention's objective is to provide a safety lock system for front pin in a quick coupler, particularly used for excavators. Another objective is to provide a front pin safety lock system that works even when power off situation.

The objects are achieved by the features of the independent claim. The other claims and the description disclose advantageous embodiments of the invention.

According to first aspect of the invention, a quick coupler apparatus comprising body (10), pivot pin (101) attached to the body (10), locking arm (100) pivotally attached to the pivot rod (101), actuator (120) comprising a cylinder (121) and a piston rod (122) which moves in the cylinder (121), rear wedge (130) attached to the piston rod (122) and locking guide (110) attached to the rear wedge (130).

Moreover, the quick coupler apparatus's locking guide (110) further comprising release wedge (111) for moving the locking arm (100) into a released status when inserted underneath the locking arm, and locking stopper (112) for maintaining the locking arm (100) to a locked status when positioned above the locking arm.

Also, the quick coupler apparatus's locking guide (110) is U-shaped.

Also, the quick coupler apparatus further comprising release wedge (311) and the wedge is configured to be connected to the locking guide.

Another aspect of the invention, a quick coupler apparatus comprising body (20), front pin lock (201) configured to rotate pivotally to lock in a pin, slide ratchet (200) configured to move forward-backward to force the front pin lock to rotate, actuator (220) comprising a cylinder (221) and a piston rod (222) which moves in the cylinder (221), rear lock (230) connected to the piston rod, links configured to connect the rear lock and the slide ratchet, and casing (240) configured to house a part of the links and a part of the slide ratchet.

Also, the quick coupler further comprising pivotal rod (241) protruded from the casing.

Also, the quick coupler apparatus's links comprising a first link (211), a second link (212) and a third link (213) and the first link and the second link are movably joined by first link joint (215), and the second link and the third link are movably joined by second link joint (216).

Also, the quick coupler further comprising protruded pin (243) configured on the surface of the rear lock (230), and rear lock stroke hole (214) configured within the first link.

Also, the quick coupler's second link (212) is connected with the pivotal rod (241) by rod pin (242).

Also, the quick coupler's length ratio from the first link joint to pivotal rod and from the pivotal rod to the second link joint is 1 : n. (wherein, n > 0 and n is real number)

Also, the quick coupler further comprising first spring (250) configured to connect the front pin lock and the body and second spring (251) placed inside of the casing.

Also, the quick coupler further comprising emergency release handler (280) for releasing the front pin quickly.

The present invention together with the above-mentioned and other objects and advantages may best be understood from the following detailed description of the embodiments, but not restricted to the embodiments, wherein is shown:

• Fig. 1, 2 Quick coupler with front pin safety system according to the first preferred embodiment of the invention from perspective view (Fig. 1) and front the front view (Fig. 2) when the front pin lock is in released status.
• Fig. 3, 4 Quick coupler with front pin safety system according to the first preferred embodiment of the invention from perspective view (Fig. 3) and front the front view (Fig. 4) when the front pin lock is in locked status.
• Fig. 5 Detailed view of the locking guide for the first embodiment.
• Fig. 6 Quick coupler with front pin safety system according to the second preferred embodiment of the invention from perspective view.
• Fig. 7 Quick coupler with front pin safety system according to the second preferred embodiment of the invention from front view when the front pin lock is in locked status.
• Fig. 8 Quick coupler with front pin safety system according to the second preferred embodiment of the invention from front view when the front pin lock is in released status.
• Fig. 9 Quick coupler with front pin safety system according to the state of art.
• Fig. 10 Quick coupler with front pin safety system according to the state of art from front view when the front pin lock is in released status.
• Fig. 11 Quick coupler with front pin safety system according to the state of art from front view when the front pin lock is in locked status.

The detailed structure and working mechanics for this invention will be explained with figures.

Throughout this specification, a 'locked status' is a status when a bucket or any attachment attached to the arm of a certain construction equipment (i.e. an excavator) is locked to the arm so that it does not fall from the arm when the arm is raised from the ground and a 'released status' is a status when a bucket or any attachment attached to the arm of a certain construction equipment (i.e. an excavator) can be removed from the arm or freely fall from the arm when the arm is raised from the ground.

Figures 1 to 5 are describing the first embodiment.

In Fig 1, the front pin safety lock system comprises locking arm (100) and locking guide (110). The locking arm exercises pivotal movement by the pivot pin (101) and the locking arm's position is determined by the locking guide.

The actuator (120) is placed in the center of the locking guide and it exerts the power to lock or release the invention's lock system. The actuator comprises cylinder (121) and the piston rod (122) to actuate the movement. By the piston rod's backward movement (backward is a direction from the front pin area (191) from the rear pin area (190)), the rear wedge (130) is moving backward along with the piston rod and the locking guide attached to the rear wedge also moves backwards and this leads to a locked status of the lock system.

Fig 2 shows the locked status of the lock system. The rear wedge moves backwards until the piston rod's maximum extension range and can hold one of the pins of the bucket or other attachment. By the rear wedge's movement the locking guide moves backwards along with the rear wedge and its locking stopper (112) moves backwards also and it positions the locking arm in locked status.

The shape of the locking arm is such that when it is in locked status, the pin of a bucket or other attachment is prevented from sliding out by its protruding tip (100', in dotted circle).

In Fig 5, the locking guide for 1st embodiment is shown in detail. The locking guide may comprise release wedge (111) and locking stopper (112). The locking guide's structure is U-shaped with the part of "underscore '_‴ comprises locking stopper (112) and the two pillar-like parts ("I") in the 'U' both have release wedge (111). Each structure's usage will be explained with Figures 3 & 4.

In Fig 3, the actuator (120)'s piston rod (121) moves into the cylinder (121) in forward direction (forward is a direction from the rear pin area (190) to the front pin area (191)) so the rear wedge, which is connected to the piston rod, also moves in forward direction. In this case, the rear wedge is in released status because there is nothing that keeps the pin from slipping from the locked status.

In Fig 4 the locking guide, which is connected to the rear wedge, also moves in forward direction. The release wedge (111), when locking guide (110) moves along with the piston rod and rear wedge, also moves and inserted into underneath of the locking arm. Therefore, the locking arm's protruding tip (100') is lowered, making the front pin area (191) open i.e. a released status. At the same time, locking stopper (112) moves deep into the locking arm, leaving end tip (100") placed in the center of the locking stopper (112) so that the locking arm is in released status.

In Fig 2 the actuator's cylinder pushes the piston rod out in the backward direction the rear wedge moves backward along with the piston rod. In this case the rear pin area becomes locked status. The locking guide connected to the rear wedge also moves backward. The release wedge also moves backwards and is pulled out from the underneath of the locking arm. At the same time the also backwardly moved locking stopper is positioned in a region where the end tip (100") is placed at the beam of the locking stopper, pushing it down. When the end tip (100") is pushed down, the protruding tip (100') is pivotally rotating upward to make the front pin area closed so that the lock status is realized.

This way, the apparatus is exercising the pin locking and releasing mechanism.

Figures 6 to 8 are descriptions of the second embodiment.

Fig 6 shows the overview of the second embodiment of the apparatus.

In this second embodiment, the body (30) of this apparatus comprises an actuator (320), rear wedge (330), the locking guide (310) and the locking arm (300). The actuator may comprise a cylinder (321) and a piston rod (322). The piston rod (322) may be connected to rear wedge (330) and each of the locking guide (310) is connected to the rear wedge. Release wedge (311) is connected to the locking guide (310) by link joint (312). The locking arm (300) is attached pivotally movable to the body with a pivot pin (301). The release wedge (311) is shaped in a way that the thickness is thin toward the rear wedge but it gradually increases toward the locking arm (300).

The locking arm (300) equipped with a spring (301') at the pivot pin (301) so that the contact tip (300') is always pushed downward by the spring (301')'s elasticity.

Fig 7 shows when this apparatus is in a locked status in second embodiment. When the front and rear pins are within the range of front pin area (391) and rear pin area (390) respectively, is attached to the body (30) with a pivot pin (301) and it can pivotally rotate with the pivot pin (301) in the center. When cylinder (321) of the actuator (320) pushes out the piston rod (322) backwards, the rear wedge (330) connected to the piston rod (322) also moves backwards therefore placing the rear wedge in locked status. At the same time, the locking guide, connected to the rear wedge also moves backwards. The locking arm connected to the locking guide also moves backwards. The shape of the release wedge (311) and the spring (301') of the locking arm make the locking arm's contact tip to gradually move upward following the surface of the release wedge. While the contact tip is moving upward, the opposite tip (300") is moving downward and by this movement the locking arm is in locked status, locking the front pin area.

In Fig 8, when trying to change the attachment or the bucket, the actuator's piston rod moves into the cylinder (i.e. forward direction). By this movement, the rear wedge moves forward along with the piston rod, rendering the rear wedge in a released status.

Also, the locking guide (310), connected to the rear wedge, moves along with it in forward direction and the release wedge (311) does too. By the shape of the release wedge and the spring (301')'s elasticity, the locking arm's contact tip moves down following the surface of the release wedge. At the same time, the opposite tip moves up, rendering the locking arm in a released status.

Figures 9 to 11 are descriptions for an example according to the state of art.

Forward direction means a direction from the rear pin area (290) to the front pin area (291) and backward direction means a direction from the front pin area (291) to the rear pin area (290).

In this embodiment, the apparatus comprises a body (20), an actuator (220) comprising cylinder (221) and piston rod (222), rear lock (230) connected to the piston rod (222), slide ratchet (200) configured to move front pin lock (201) that is configured to lock the front pin in the front pin area (291), links (211, 212, 213) that connect the rear lock (230) and the slide ratchet (200).

The slide ratchet (200) is shaped so that it may push the front pin lock (201) in forward direction when the actuator is activated and the piston rod is pushed in backward direction. In this case the front pin lock is positioned to a released status. (because the front pin lock is open to the forward direction) A spring (250) may be installed at the front pin lock (201) so that when no outer force is engaged, the front pin lock (201) is in locked status (i.e. the front pin lock is closed). A front pivot pin (202) is installed so that the front pin lock (201) is rotationally configured in the body (200).

The links (211, 212, 213) are joined by link joints (215, 216) respectively. At the slide ratchet (200)'s rear pin area (290) direction end, the link (213) is connected to the link (212) with the link joint (216). A casing (240) covers part of the link (213) and the slide ratchet (200) with a hold which lets the link (213) move forward and backward directions. A pivotal rod (241) is configured at the end the casing (240) and rod pin (242) is connecting the link (212) and the pivotal rod (241).

A spring (251) may be installed in the casing so that it touches the casing's backward direction wall and the slide ratchet. This spring (251) may exert elastic force to keep the slide ratchet's position in place. Another spring (250) may connect between the front pin lock (201) and an appropriate place in the body (20). The spring (250) may place the front pin lock (201) in place, i. e. keep the front pin lock (201) closed for locked status.

Fig 10 describes when the example front pin lock (201) is in released status (open).

As the piston rod (222) moves to the backward direction, the first link (211) connected to the piston rod (222) also moves to the backward direction. The second link (212), rotatably fixed by the rod pin (242), rotates in counter-clockwise direction. The second link joint (216) moves in forward direction along with the third link (213).

The slide ratchet (200) moves forward direction along with the third link so that the front pin lock (201) opens to be in released status. The spring (250) may keep the front pin lock (201) in contact with the slide ratchet (200).

Fig 11 describes when the example front pin lock (201) is in locked status (close).

As the piston rod (222) moves to the backward direction, the first link (211) connected to the piston rod (222) also moves to the backward direction. The second link (212), rotatably fixed by the rod pin (242), rotates in clockwise direction. The second link joint (216) moves in backward direction along with the third link (213).

The slide ratchet (200) moves backward direction along with the third link (213) so that the front pin lock (201) closes to be in locked status. The spring (250) may keep the front pin lock (201) in contact with the slide ratchet (200).

The rear lock stroke hole (214) can be configured in the first link (211). When this stroke hole is in the first link, the first link is connected to the rear lock (230) with protruded pin(s) (243).

The protruded pin (243) is on the surface of the rear lock (230) and it is positioned inside the stroke hole (214) and when the rear lock moves the protruded pin also moves with the rear lock.

This stroke hole (214) and the protruded pin (243) can provide a slack in the movement of the front pin lock (201).

When the piston rod (222) moves forward or backward, the rear lock (230) moves at the same time. However, the links (e.g. the first link (211)) do not move until the protruded pin (243) meets the end of the hole. Until the encounter, the links do not move.

This slight 'lack of movement' gives some stroke slack to this apparatus because if all the components in this apparatus move with the piston rod immediately, there can be some shortcomings due to the extra-sensitivity from it.

The second link (212) has a fixed rotation center in the middle (rod pin, 242). The rod pin divides the second link in a certain way. For maximum efficiency and prolonging parts life, the length ration can be varied.

The length ratio from the first link joint (215) to the pin rod (242) to from the pin rod (242) to the second link joint (216) is 1 : n, wherein n is a positive real number.

However, if the ratio is too big (for example, n is smaller than 1) the first link (211) should move long enough to get the slide ratchet (200) move enough so that the front pin lock (201) can open (i.e. released status). This long movement sometimes can lead into malfunction.

On the contrary, if the ratio is too small (for example, n is much bigger than 1) the first link (211) may move just a little to get the slide ratchet move for released status. But, it would require so much force to move the slide ratchet when front pin is attached so the links, especially the second link and then the first link are under too heavy pressure every time they move. This can lead into snapping and dangerous.

So, good length ratio for maximizing the efficiency and prolonging part life is important.

For better changing the ratio for supporting each work's characteristics, the second link (212) has multiple puncture holes in it.

This front lock mechanism is mechanical not electrical or electronic, so the front lock system works when even power cut off (i.e., no hydraulic power).

For emergency, the emergency release handler (280) may be manipulated so that the second link joint (216) ejects from its position. In this case, the spring (251) exerts its force to the slide ratchet (200) to release the front pin in spite of the spring (250).

• 10, 20, 30: Body
• 100, 300: Locking arm
• 100': Protruding tip
• 100": End tip
• 101, 301: Pivot pin
• 101', 301': Spring
• 110, 310: Locking guide
• 111,311: Release wedge
• 112: Locking stopper
• 120, 220,320: Actuator
• 121, 221, 321: Cylinder
• 122,222, 322: Piston rod
• 130, 330: Rear wedge
• 190, 290, 390: Rear pin area
• 191, 291, 391: Front pin area
• 200: Slide ratchet
• 201: Front pin lock
• 202: Front pivot pin
• 250, 251: Spring
• 211, 212, 213: Link
• 214: Rear lock stroke hole
• 215, 216, 312: Link joint
• 230: Rear lock
• 240: Casing
• 241: Pivotal rod
• 242: Rod pin
• 280: Emergency release handle
• 300': Contact tip
• 300": Opposite tip