Injection device (modified trigger)

ES 2 365 862 T3

DESCRIPTION

Injection device (modified trigger)

Field of the invention

The present invention relates to an injection device of the type that receives a syringe, extends it, discharges its contents and then automatically retracts it.

Background of the invention

Previously known injection devices are shown in WO 95/35126 and EP-A-0 516 473 and tend to employ an actuation spring and a trigger which, when actuated, causes the actuation spring to act on the syringe when a releasable locking mechanism is also attached.

In general, the trigger is rotatable about an axis, so that when it is depressed at a first end, a second end (which normally engages the actuation spring) is also rotated, thereby releasing the actuation spring, extending the syringe and discharging its contents. The trigger comprises a protrusion that can engage with a notch in the releasable locking mechanism when the releasable locking mechanism engages, thereby allowing the trigger to be activated. When the releasable locking mechanism is not engaged, the protrusion contacts a portion of the releasable locking mechanism preventing rotation of the trigger and release of the actuation spring. In this way, accidental activation of the trigger can be avoided.

One problem with such an injection device is that the protrusion in the trigger flexes when a force is applied to the trigger and the releasable locking mechanism is not engaged. A large force applied to the trigger can cause sufficient flexion at the protrusion that the end of the protrusion can engage the notch in the releasable locking mechanism, thereby allowing the trigger to be activated even when the releasable locking mechanism has not been docked.

US 6575939 B describes an injection device having a locking mechanism that prevents the trigger from being activated until the locking mechanism is moved to an activated position. The trigger comprises a side bar that must mate with corresponding openings in the locking mechanism before it can be activated.

Summary of the invention

The injection device of the present invention is designed to address this and other problems.

In view of the foregoing and according to a first aspect of the invention, an injection device is provided comprising:

a housing defining a first axis and adapted to receive a syringe having a discharge cannula, such that the syringe is movable between a retracted position in which the discharge cannula is contained within the housing and an extended position in wherein the discharge cannula extends from the housing through an outlet opening;

a driving mechanism that is acted upon and which, in turn, acts on the syringe;

a trigger removable from a resting position, in which it causes the drive mechanism to be held, to an active position, in which it no longer causes the drive to be so held, thus allowing the contents of the syringe to be discharged through the discharge cannula; and a releasable locking mechanism movable from a first position in which the trigger is prevented from moving to its active position to a second position in which the trigger can be moved to its active position, in which the trigger includes a first portion having a notch therein, the first portion extending from a first end of the trigger in a direction substantially parallel to the first axis; and the releasable locking mechanism includes a protrusion along a second axis to communicate with the first portion of the trigger when the releasable locking mechanism is in its first position and to communicate with the notch when the releasable locking mechanism is in its first position. in his second position.

Therefore, when a force is applied to the trigger when the locking mechanism is in its first (i.e. engaged) position, the first portion of the trigger and the protrusion both flex in such a way as to force protrusion away from the notch, thereby reducing the risk of accidental activation of the trigger.

ES 2 365 862 T3

In one embodiment of the invention, the protrusion comprises a first projection adapted to communicate with an edge of the notch when the releasable locking mechanism is in its second position and the trigger is in its active position, thereby preventing, trigger movement from its active position to its rest position.

In addition, the trigger may further include a second portion that extends into the notch from the first portion of the trigger and is arranged to communicate with the shoulder when the releasable locking mechanism is in its second position and the trigger is in position. in its active position.

Consequently, the trigger can be held in a rotated position after activation, thereby serving to indicate that the injection device has been used.

Preferably, the releasable locking mechanism comprises a biasing means arranged to bias the protrusion against the second portion.

Advantageously, the first portion of the trigger comprises a second projection located in the first portion, so that the protrusion is located between the notch and the second projection when the trigger is in its rest position, so that the second projection communicates with the protrusion if an attempt is made to move the trigger from its resting position.

The second shoulder prevents the first portion of the trigger and the protrusion from flexing such that the end of the protrusion extends beyond the end of the first portion, which would result in the trigger being able to rotate.

The protrusion may comprise a sloped surface that is inclined with respect to the second axis, thereby ensuring that the protrusion enters the notch smoothly when the locking mechanism is disengaged.

Preferably, the first axis and the second axis are perpendicular to each other, which ensures that the protrusion and the first portion are optimally arranged to ensure that the protrusion enters the notch when the locking mechanism is disengaged, but it also means that the protrusion and the first portion will flex in such a way as to prevent accidental activation of the trigger when the release mechanism is engaged.

Brief description of the drawings

The invention will now be described by way of example with reference to the accompanying drawings, in which:

Figure 1 shows a perspective view of an injection device according to the present invention;

Figure 2 shows a side view of the injection device of Figure 1 with an upper section of its housing not shown;

Figure 3 shows a side view of the injection device of Figure 2 with additional components not shown;

Figure 4 shows a plan view of the injection device of Figure 2;

Figure 5 shows a perspective view of a trigger and releasable locking mechanism according to an embodiment of the present invention; and Figure 6 shows an alternate perspective view of the trigger and releasable locking mechanism of Figure 5.

Detailed description of the drawings

Figures 1 to 4 show an injection device 110 according to a first embodiment of the present invention. The injection device 110 has an injection device housing 112 and a longitudinal axis 101.

A syringe 122 is contained in housing 112. Injection device 110 comprises a trigger 114 and a releasable locking mechanism 116. Trigger 114 has a first end 114a and a second end 114b. Trigger 114 is rotatable about pivot 115 from a rest position (as shown in Figure 2) to an active position. The second end 114b of the trigger 114 connects with a drive coupling 121 which is actuated by means of a drive spring 120. Drive coupling 121 is in communication with syringe 122.

Rotation of trigger 114 about pivot 115 in a direction R (i.e., downward into housing 112 at its first end 114a) causes second end 114b of trigger 114 to disengage from engagement.

ES 2 365 862 T3 drive 121, thereby allowing drive spring 120 to drive syringe 122 (via drive coupling 121) along longitudinal axis 101 and out of an opening 118 in housing 112.

Releasable locking mechanism 116 is in communication with sliding sleeve 126 which protrudes, when in a first position, from opening 118 in housing 112. Locking mechanism 116 is deactivated by movement of sliding sleeve 126 along longitudinal axis 101 into housing 112 in a second position.

A first end 126a of the sliding sleeve 126 can be placed against a body to which a drug is delivered, thereby deactivating the releasable immobilization mechanism 116 and allowing the trigger 114 to rotate in the R direction from its rest position. to its active position.

As can be seen in Figures 5 and 6, the trigger 114 is provided at its first end 114a with a first portion 150 having a notch 152. The first portion 150 extends from the first end 114a of the trigger 114 in a substantially parallel direction. to the longitudinal axis 101.

Releasable locking mechanism 116 includes a protrusion 154 projecting in a direction along a perpendicular axis 181 that is perpendicular to longitudinal axis 101. Notch 152 is dimensioned to receive protrusion 154.

When releasable locking mechanism 116 is in its first position, one end 154a of protrusion 154 contacts a bottom surface 156 of first portion 150, thereby preventing rotation of trigger 114.

When releasable locking mechanism 116 is in its second position (not shown) following movement of sliding sleeve 126 into housing 112, notch 152 is positioned above the end of protrusion 154, allowing it to pass over the protrusion. 154 when a downward force is applied to trigger 112. Thus, trigger 112 is no longer prevented from rotating and disengaging from drive coupling 121, thereby extending syringe 122.

Protrusion 154 comprises a first shoulder 160. Trigger 114 includes a second portion 162 which extends into notch 152 from first portion 150 of trigger 114 and is arranged to communicate with second portion 162 after rotation of the trigger 114, so that the first shoulder 160 is immobilized on the second portion 162, thereby preventing movement of the trigger 114 from its active position back to its rest position.

The locking mechanism 116 includes biasing means, in the form of resilient arms 171, which act against the internal surface of the housing 112 to push the locking mechanism 116 and the sliding sleeve 126 in a direction away from the opening 118. In this way After activation of trigger 112, first projection 160 is immobilized on second portion 162 of trigger 112, thereby maintaining trigger 112 in its active position.

The first portion 150 of the trigger comprises a second shoulder 164 on the lower surface 156 of the first portion 150 that is positioned between the notch 152 and the end of the first portion 150. The second shoulder 164 contacts the protrusion 154 when engaged force on trigger 114 in a direction R and the release mechanism is in its first (ie, engaged) position. This prevents protrusion 154 from moving to a position where its end 154a moves over the end of first portion 150, which would allow trigger 114 to rotate while releasable locking mechanism 116 was still engaged, "firing. "Accidentally, thereby, the injection device 110.

Protrusion 154 has a sloped surface 166 that is inclined relative to second axis 181 that allows second portion 162 of trigger 114 to pass over protrusion 154 more efficiently when trigger 114 is rotated and releasable locking mechanism 116 is disengaged.

Of course, it will be understood that the present invention has been described above merely by way of example and modifications of detail may be made within the scope of the invention.