Patent Application
20090171298
The present invention relates to a syringe for use with a carpule and needle, more specifically, to a retractable syringe that permits the needle to be obscured from view as desired.
In recent years there has been growing concern related to the safety of syringes. Conventional needles are provided with a cap or cover which is removed once the needle is affixed to the syringe. At this time, there is a potential for the practitioner or the patient to be inadvertently stuck with the needle or for contamination of the needle. Syringes with retractable needles have been developed to overcome these issues and enable the practitioner to expose the needle only when necessary.
Typically, a retractable needle has two positions, retracted and extended. The needle must be placed in the fully extended position in order to prepare the needle for administration of the injection by depression of a plunger and dispensing of the carpule contents. In addition, many retractable needles such as the SMART SYRINGE® (SMART SYRINGE is a registered trademark of Sakharam Mahurker, Chicago, Ill., USA) provide only a single use and are not environmentally friendly.
In the field of dentistry, injections are a common fear identified in dental patients. Recent studies have shown that both the patient and the dentists may be traumatized on viewing the needle portion of a syringe when receiving dental syringe injections. There have many dental syringes developed specifically to reduce or eliminate patient anxiety on receiving injections. These syringes are typically marketed as “patient friendly” syringes, however “patient friendly” has often referred to a reduced time period associated with receiving an injection not needle related anxiety.
The Wand® (The Wand is a registered trademark of Milestone Scientific Inc., Livingston, N.J., USA) is a computer controlled dental injection system that is intended to alleviate or reduce patient pain and anxiety associated with receiving injections by controlling the speed at which the injection is administered by a computer. The Wand® resembles a ballpoint pen and is easier for dentists to handle because its light weight. However, this device is both costly to purchase and operate, and time consuming to prepare and perform the injection.
The Comfort Control® Syringe (Comfort Control is a registered trademark of Midwest Dental Products Corp., Des Plaines Ill., USA) was developed to deliver a more predictable and comfortable injection in sensitive areas such as the palate or front of the mouth. The syringe is wired to a microprocessor which directs a steady, slow injection regardless of tissue density.
Another device, the Vibraject provides a motor attached to a conventional syringe that causes the needle portion of the syringe to vibrate. The high vibration of the needle stimulates the nerve endings and blocks the transmission of pain to the brain.
Exemplary embodiments of the present invention relate to a syringe assembly having an extendable and retractable outer shell for exposing a needle.
An exemplary embodiment relates to a syringe assembly comprising a holder for receiving a container having a medicament, a plunger slidably received in the holder and an outer shell having an inner surface where a portion of the inner surface slidably engages an outer surface of the holder. A forward end of the plunger selectively engages the container to dispense the medicament through a needle. The outer shell is movable between an extended position and a retracted position for exposing the needle. The plunger and the holder are movable as a unit relative the outer shell when the outer shell moves between the extended position and the retracted position. When the outer shell is in the retracted position, the plunger is movable to a dispensing position.
In one embodiment, a proximal end of the outer shell is biased toward the holder. The proximal end may include a protrusion for selectively engaging a depression in the outer surface of the holder, and the outer shell is then biased toward the depression.
An alternative exemplary embodiment relates to an outer shell for a syringe comprising an inner surface, a portion of said inner surface slidably engaging an outer surface of a holder and a proximal end biased toward the holder for selectively engaging the outer surface of the holder. The holder is configured for receiving a container having a medicament. The outer shell is movable between an extended position and a retracted position for exposing a needle. When the outer shell moves between the extended position and the retracted position, a plunger slidably received in the holder, and the holder are movable as a unit relative to the outer shell. When the outer shell is in the retracted position, a forward end of the plunger is movable relative to the holder in a dispensing direction to dispense the medicament through the needle.
In one embodiment, the proximal end further includes a protrusion for selectively engaging a depression in the outer surface of the holder. The protrusion of the outer shell is biased toward the depression.
In another embodiment, the outer surface of the holder has a first depression and a second depression. When the protrusion engages the first depression, the position of the outer shell corresponds to the extended position. When the protrusion engages the second depression, the position of the outer shell corresponds to the retracted position. In a further embodiment, the protrusion is formed on an inner wall of the outer shell.
In another embodiment, the holder further includes a channel formed in the outer surface. The channel continuously engages the protrusion of the outer shell. In yet another embodiment, the depression is formed in the channel.
In one embodiment, the outer surface of the holder further includes at least one intermediate depression. In another embodiment, the outer surface of the holder further includes two intermediate depressions. In yet another embodiment, the outer surface of the holder further includes a plurality of intermediate depressions. When the protrusion engages an intermediate depression, the position of the outer shell corresponds to a partially retracted position.
In one embodiment, an outer wall of the outer shell has a window formed therein.
In another embodiment, the syringe assembly further includes a spring biased toward the container for resiliently retaining the container in the holder.
In one embodiment, the outer shell is transparent. In another embodiment, a portion of a distal end of the outer shell is textured to obscure the needle.
In one embodiment, the syringe assembly is self-aspirating.
In a further embodiment, the outer shell is constructed of a suitable flexible material that is temporarily deformable. The suitable flexible material is selected from the group consisting of plastics, metals, compliant polymeric material and combinations thereof. The compliant polymeric material may be shaped into a child-friendly shape, for example an animal head, an animal, or a tooth. A portion of the proximal end of the outer shell may further include an outer coating of a compliant polymeric material.
In one embodiment, the outer shell is injection molded. Alternatively, the syringe assembly may be injection molded.
The foregoing and other features and advantages of the syringe assembly will become more apparent from the following detailed description, which proceeds with reference to the accompanying figures.
Embodiments of the present invention will now be described, by way of example only, with reference to the attached Figures, wherein:
Some exemplary embodiments of the present invention relate to a syringe having a needle that is retractable and extendable such that the needle may be advanced through a series of specific needle positions, until the needle is fully extended.
A carpule syringe facilitates repeated use, specifically repeated loading of carpules and enables easy insertion of doses of a medicament and discharge of exhausted containers. A carpule is a container or cartridge having a medicament therein. A carpule syringe is characterized by the absence of a fixed barrel in which a piston reciprocates. Instead, a carpule syringe includes a shell with an opening designed to receive a medicament filled carpule, the ends of which are closed and hermetically sealed. The frame is provided with a reciprocatable shaft arranged to engage with one end of the carpule such that when the shaft is pushed forwardly in the frame, it will apply pressure to the liquid medicament within the carpule so as to dispense the same through a needle.
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In another exemplary embodiment, the outer surface 21 of holder 18 further includes two intermediate depressions for selectively engaging the protrusion 50 of outer shell 16. The first intermediate depression 31 defines a first intermediate position 33 and the second intermediate depression 35 defines a second intermediate position 37. The second intermediate depression 35 is proximate to the second depression 32 and the first intermediate depression 31 is distal to each of the second intermediate depression 35 and the second depression 32. The outer shell 16 in an extended position and the second position 34 corresponds to the outer shell 16 in a retracted position.
Protrusion 50 of outer shell 18 is movable between the first 38 and second 34 positions. The first position 38 corresponds to the outer shell 16 in an extended position and the second position 34 corresponds to the outer shell 16 in a retracted position. In another exemplary embodiment, the first intermediate position 33 and second intermediate position 37 both correspond to the outer shell 16 in a partially retracted position where only a portion of needle 14 is visible. When protrusion 50 is engaged in the second intermediate depression 35, a greater portion of needle 14 is visible compared to when protrusion 50 is engaged in the first intermediate depression 31.
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In one embodiment, a portion of a distal end 47 of outer shell 16 is textured to obscure viewing of needle 14. In another embodiment, a portion of the proximal end 48 of outer shell 16 is coated or otherwise covered with a polymeric material that is similar to that material found on toothbrushes.
In another embodiment, the syringe assembly of the present invention can be manufactured by methods known to those skilled in these arts. More particularly, the outer shell 16 can be injection molded in two identical pieces that are then joined together or in a single mold. In a further embodiment, each of holder 18 and plunger 24 may also be injection molded.
In one embodiment, the outer shell 16 is constructed from suitable flexible materials such as plastics, metals, or other materials known in the art that. The proximal end 48 of the outer shell 16 may be temporarily deformed to enable the proximal end 48 to be biased toward the holder 18.
The syringe assembly 10 to load the syringe assembly 10 with a carpule, a user pulls plunger 24 away from the proximal end 48 of outer shell 16 such that the plunger 24 is fully extended, spring 23 is in tension, and aperture 15 of holder 18 is exposed for loading a carpule 12 in holder 18. Once the carpule is loaded, the plunger 24 slides forward toward the proximal end 48 of outer shell 16, spring 23 is biased toward the carpule holding the carpule resiliently in place in holder 18, and the protrusion 50 is engaged in the first depression 36. In another embodiment, the syringe assembly 10 may be loaded with a carpule using methods known to persons skilled in the art.
In use, the syringe assembly once loaded with a carpule 12, the outer shell 16 is in an extended position such that needle 14 is in a retracted position and is completed covered by the outer shell 16 as shown in
The user then applies pressure to the plunger 24. The plunger 24 and holder 18 move as a unit relative to outer shell 16, and the protrusion 50 springs out of the first depression 36, and the holder 18 and plunger 24 together slidably engage the outer shell 16 sliding toward the distal end of outer shell 16 until protrusion 50 engages a first intermediate depression 31. In this first intermediate position 33 a portion of needle 14 is visible and the outer shell 16 is partially retracted. Pressure continues to be applied by the user and protrusion 50 springs out of the first intermediate depression 31, the holder 18 and plunger 24 continue to slide as a unit in the outer shell 16 until protrusion 50 engages a second intermediate depression 35. In this second intermediate position 37, a greater portion of needle 14 is visible and a greater portion of the outer shell 16 is partially retracted. Pressure continues to be applied by the user and protrusion 50 springs out of the second intermediate depression 35, the holder 18 and plunger 24 together continue to slide as a unit in outer shell 16 until protrusion 50 then engages the second depression 32. In this second position 34, the outer shell 16 is in a retracted position such that needle 14 is in an extended position as shown in
Upon reaching the second depression, the user applies further pressure to plunger 24. The plunger 24 slides in holder 18 and the forward end 25 of the plunger 24 selectively engages the container 12. The continued pressure by the uses moves the plunger 24 to a dispensing position and urges the contents of the carpule 12 from the carpule 12, through the needle 14.
The above-described embodiments have been provided as examples, for clarity in understanding the invention. A person of skill in the art will recognize that alterations, modifications and variations may be effected to the embodiments described above while remaining within the scope of the invention as defined by the claims appended hereto.
This application is a Continuation-in-Part of co-pending U.S. application Ser. No. 12/002,117, filed Dec. 13, 2007, herein incorporated by reference.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 12002117 | Dec 2007 | US |
| Child | 12334415 | US |
