Such known veterinary syringes
Such known veterinary syringes, also referred to as repeater syringes, are used for mass vaccination of sheep, swine and cattle, and thus have to withstand high stresses. Above all, such syringes need to be insensitive to soiling, in particularwith regard to the operating and adjusting elements provided on such syringe.
The invention relates to a veterinary syringe, comprising a base body, on the front side of which a syringe barrel receiving the medicament is arranged while a guiding element for a plunger rod that is guided therein so as to be movable in alongitudinal direction is arranged on the rear side thereof, and one end of said plunger rod, to which a plunger is attached, extends into the syringe barrel, said syringe further comprising a handle for holding the syringe, an operating lever, one endof which is pivotably attached to the lower part of the handle while the other end thereof is guided within the bottom side of the guiding element and engages with a toothed rack via a spring-biased catch, said toothed rack being disposed on the bottomside of the plunger rod, and a locking device for the plunger rod which engages with the toothed rack is provided as a locking slider disposed inside the guiding element so as to be movable in a vertical direction at the end thereof, is provided with anopening through which the plunger rod is guided and extends into the toothed rack from below, locking said toothed rack so as to prevent it from withdrawing, wherein said locking slider can be moved from the locked position into a released position forthe toothed rack and can be maintained in said released position by means of an actuator.
In such a known syringe, the locking device is also provided in the form of a locking slider, which is arranged within the guiding element for the plunger rod so as to be vertically movable, encompasses the plunger rod and extends into thetoothed rack from below, under a spring load. The locking slider may be pushed down from above, against a spring force, so as to release the toothed catch and to allow retraction of the plunger rod. In order to maintain the locking slider in itspushed-in form, the known veterinary syringe has an annular lock which is arranged on the guiding element so as to be movable thereon in a longitudinal direction, in the region of the guiding element which extends between the base body and/or the handle,on the one hand, and the catch attached to the operating lever, on the other hand.
When the operating lever is in its resting position, i.e. at its greatest distance from the handle, the lock may be moved back toward the operating lever, or the catch attached thereto may be moved along the guiding element, with the lock pushingthe locking slider down against the pressure of a spring, or then maintaining it in this position, respectively. In this condition, the plunger rod can be pulled back. If the syringe is operated again, i.e. if the operating lever is moved forwardtoward the handle, then the operating lever or the catch, respectively, pushes the lock forward, thus releasing the locking slider, which moves out of its locked position due to the spring load and releases the plunger rod, so that vaccinations can becarried out.
Providing the lock as a ring which is movable on the guiding element in a longitudinal direction has the disadvantage that it becomes increasingly difficult for said lock to slide on the guiding element due to the constant soiling of this area bythe use of the syringe, which may eventually cause the syringe, or in particular, the lock and, thus, the locking device, to be no longer operable or releasable.
In the above-described veterinary syringe, this problem is solved by the locking slider being extended so as to protrude out of the bottom of the guiding element toward the operating lever, said extension comprising a bore, by the locking pinbeing provided on the operating lever, which is arranged parallel to the plunger rod, and by the locking pin extending into the bore, in the resting position of the operating lever, when the locking slider is pressed down through the guiding element allthe way to the locking pin against the force of a spring.
Due to said aforedescribed design, the fixing mechanism for the locking slider for releasing the plunger rod is placed at a distance from the area of the guiding element located between the operating lever, on the one hand, and the handle orcatch, respectively, on the other hand, in an area which is arranged in a protected manner in the operating lever, i.e. away from sources of soiling. According to the invention, the lock itself is provided as a simple locking pin which need not beadjusted or displaced as in the case of the prior art lock. If the locking slider is pressed down, its bore engages with the locking pin, and said locking pin does not release the locking slider again until the locking pin is pushed forward, out of itsresting position by actuation of the operating lever, so that the locking slider can move up again, into the locked position, under the action of a spring.
Therefore, it is an object of the invention to provide a lock or a locking device, by which the aforedescribed disadvantages of the known veterinary syringes, are avoided, said lock or locking device further being of a simpler construction oreasier to manufacture and increasing the overall robustness of the veterinary syringe.
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