A stopper being adapted to be fixed in a rear end portion of a syringe is provided. The stopper is reduced in diameter at a fitting portion of a rod portion of a plunger rod so as to have a diameter smaller than an inner diameter of the rear end portion and be insertable into the rear end portion. After insertion, the stopper is increased in diameter and is fixed in the rear end portion so as not to be movable in an axial direction by fitting a first recessed portion on a periphery into a second protruding portion of an inner surface of the rear end portion. The stopper has, on an inner surface, a third protruding portion having an inner diameter smaller than an outer diameter of a gasket support flange of the rod portion in a fixed state.

A drive unit for an injector includes an elastomeric drive member configured to possess a first elastic potential energy in an elastically stretched state that is releasable to convert the elastic energy to a first biasing force. A selectively releasable plunger rod has a locked position maintaining the elastomeric drive member in the elastically stretched state. A trigger member is biased by a second biasing force into an interlocking position. In the interlocking position, an arm of the trigger member interlocks with a notch of the plunger rod, thereby maintaining the plunger rod in the locked position thereof. The trigger member is selectively movable against the second biasing force to an unlocking position spaced from the notch, thereby releasing the first elastic potential energy into the first biasing force to axially advance the plunger rod and thus advance the piston through the reservoir.

A syringe assembly, comprising a syringe barrel having a forward end and a rearward end and being arranged along a longitudinal axis; a restricting element, moveably supported onto a portion of the syringe assembly and positionable in one of an injection disabling position and an injection enabling position in different operative orientations of the syringe assembly; a plunger rod assembly displaceable within the syringe barrel and operatively coupled with the restricting element; the plunger rod assembly having a restricting feature adapted to cooperate with the restricting element, such that when the restricting element in the injection disabling position, the plunger rod assembly is permitted to be displaced axially forwardly only up to a certain longitudinal extent relative to the syringe barrel and when the restricting element is in the injection enabling position, the plunger rod assembly is permitted to be further displaced axially forwardly relative to the syringe barrel.

A needleless injector includes a housing part that includes an accommodating space and defines a flow path for ejection, a driving part that imparts ejection energy, and a plunger that defines the accommodating space and is disposed to move in the housing part by the ejection energy and pressurize a substance intended for injection. The plunger includes a weakened part that causes a part of the plunger to deform such that, when force applied to the plunger exceeds predefined force while the driving part is imparting the ejection energy with the accommodating space accommodating the substance intended for injection, a distal end of the plunger does not reach an inner wall surface at a deepest part of the housing part or force received by the inner wall surface falls within a predetermined range until the distal end of the plunger reaches the inner wall surface.

An injection training device is configured to simulate the tactile sensations and forces associated with the operation of a corresponding injection device. However, the injection training device does not carry the medication or a needle. The injection training device includes a plunger that is depressed to drive a rotor to rotate. A viscous fluid resists rotation of the rotor, which thereby resists depression of the plunger.

An assembly for advancing a piston through a rotationally fixed cartridge includes a rotatable, axially fixed first member and an axially movable, rotatable second member connected thereto via a threaded connection and connectable to the piston. A friction pad is rotationally fixedly connected with the second member and includes first and second sets of fingers extending radially outwardly from a central disk. Both the first and second sets of fingers are configured to contact an interior side wall of the cartridge. The first set of fingers are angled toward a first rotational direction and are configured to wedge the friction pad between the side wall and the second member upon rotation of the first member in the first direction, thereby substantially preventing rotation in the first direction. The second set of fingers are angled toward a second rotational direction and are configured to substantially prevent rotation in the second direction.

A fluid dispensing device having a barrel having a lumen for containing a fluid therein and a flexible structure extending from the barrel. A plunger is axially slidable within the lumen to dispense fluid from the barrel, the plunger having a first set of grooves spaced apart a first distance and a second set of grooves spaced apart a second distance. The flexible structure includes a flexible arm extending transversely with respect to the barrel and configured to engage the grooves.

A device for facilitating positioning of a needle during a medical procedure may include a needle receiver configured for removable/reversible attachment of a proximal end of a needle; a stop set back from a distal end of the needle receiver and against which a needle received by the needle receiver abuts; and a trigger configured to move the needle receiver relative to the stop when activated by a user such that the stop forces detachment between the needle receiver and the needle. The device may monitor the pressure at the distal end of the needle as the needle is advanced and provide indication to a user when a predetermined pressure or pressure differential is reached.

An intraocular lens injector with controlled insertion has in a pen-like casing (1) a rear part including an actuator (18) connected anteriorly to an insertion rod (19) for inserting the intraocular lens (IOL) in a patient's eye, and an intermediate handle portion (6) on which a device for controlling the advancement of the push rod (9) is provided. The push rod (9) has a prismatic shape, and is provided with a toothed rack (24), and the device for controlling the advancement of the push rod (9) engages and disengages with respect to the toothed rack (24) co-operating as an elastic return element abutting the pen-like casing (1) to control the advancement of the push rod (9).

This application relates to force reduction in injection devices. According to a first aspect, the specification describes an injection device comprising: a medicament container; a stopper translatably disposed within the medicament container; a plunger rod, the plunger rod comprising a plunger head; a drive mechanism for displacing the plunger rod into the medicament container; and a force reduction feature, wherein the plunger rod is operable to displace the stopper; and wherein the force reduction feature is arranged to damp at least a part of a plunger rod motion when the plunger rod is driven by the drive mechanism.