ADJUSTABLE CERVICAL COLLAR LOCK

Abstract: An adjustable cervical collar lock (88) is disclosed. The lock or lock stop means (310, 311) engages a locking mechanism (90) of an adjustable cervical collar (10) and prevents further sliding of the adjustment system means.

Description: ADJUSTABLE CERVICAL COLLAR LOCK Technical Field This invention relates to cervical collars. More specifically, this invention relates to a lock for a cervical collar with an adjustable sternum and shoulder brace. Background Art Numerous types of cervical collars have been disclosed, which are designed to restrict the movement of the head and neck of a person who has suffered a neck or spinal injury. In fact, cervical collars are now standard equipment for emergency medical service squads and rescue units in many localities. Low-cost, cervical collars must be available in numerous sizes to fit various individuals. For example, a cervical collar for a small child requires a different size than a cervical collar for an adult. This problem has been partially addressed by providing different sizes of cervical collars for different sizes of individuals. It is desirable, therefore, that inexpensive cervical collar be adjustable to different sizes, but still effectively immobilize the neck of a patient. A desirable adjustable cervical collar can be fitted onto an injured individual placing the cervical collar in position behind the patient and then adjusting the frontal portion of the cervical collar to immobilize the neck of the patient. This procedure for fitting an individual is desirable regardless of the patient's size. As a result, a number of cervical collars have been designed which permit expansion of the neck supporting piece or "sternum and shoulder brace" to better support the patient's neck. Early models of these cervical devices allow for the vertical extension of the neck supporting piece or sternum and shoulder brace of the cervical collar. Some adjustable cervical collars permit modest adjustments to the location of the neck piece. Many of these devices, however, are not easily adaptable for placement around the patient in an emergency medical situation. These devices do not provide adjustable neck support pieces, which can be adjusted in height while the back portion of the cervical collar is held in place against the patient's neck and then securely locked for transport of the patient. These devices for adjusting the neck support or sternum and shoulder brace fail to permit automatic parallel adjustment to both sides of neck support or sternum and shoulder braces. The industry lacks an adjustable cervical collar wherein the neck to sternum portion and shoulder brace can be easily adjusted and locked. Summary of Invention The invention is a locking means for an adjustable cervical collar. The adjustable cervical collar has an elongated neck encircling band, a chin support brace, and an adjustable sternum and shoulder brace with an adjustment system means for adjusting the height of the sternum and shoulder brace in relation to the elongated neck encircling band. The adjustable sternum and shoulder brace can be adjusted in height with relation to the chin support brace. The locking means releasably fixes the adjusted sternum and shoulder brace in a position to support the neck of the patient. The preferred locking means includes a sliding clip means to engage and hold an adjustment system means of ratchet teeth and pawl. Brief Description of the Drawings Figure 1A is a front plan view of the adjustable cervical collar in a flat position. Figure IB is an edge view of the adjustable cervical collar in a flat position. Figure 1C is a side perspective view of the adjustable cervical collar with the chin support brace in a bowed or operable position. Figure 2 is the elongated neck encircling band of the adjustable cervical collar. Figure 3 is a side view of a two-piece chin support brace of the adjustable cervical collar. Figure 4 is a side view of the j-shaped element of the two- piece chin support brace of the adjustable cervical collar. Figure 5 is a side view of the two-piece chin support brace of the adjustable cervical collar with an alternative locking feature. Figure 6A is a front plan view of the sternum and shoulder brace of the adjustable cervical collar. Figure 6B is an end view of the sternum and shoulder brace of the adjustable cervical collar. Figure 7A is an edge view of the locking mechanism having a ratchet teeth and pawl system where downward movement of the sternum and shoulder brace is permitted. Figure 7B is an edge view of the locking mechanism having the ratchet teeth and pawl system where upward movement of the sternum and shoulder brace is permitted. Figure 7C is an edge view of the locking mechanism having the ratchet teeth and pawl system where no movement of the sternum and shoulder brace is permitted. Figure 8A is the front plan view of the cover piece of the adjustable cervical collar. Figure 8B is a side view of the cover piece of the adjustable cervical collar. Figure 9 is the slide piece containing a pawl for use with the adjustable cervical collar. Figure 10 is a front plan view of the adjustable cervical collar having locking mechanism with a locking stop means. Figure 11 is a partial side view of a disengaged locking mechanism, allowing free movement of the adjustable cervical collar, and with a locking stop means in an unlocked position. Figure 12 is a partial side view of an engaged locking mechanism, not allowing free movement of the adjustable cervical collar, and with a locking stop means in a locked "safety" position. Figure 13 is a partial side view of an engaged locking mechanism, not allowing free movement of the adjustable cervical collar, and with a locking stop means in a fully locked position. Figure 14 is a partial side elevational view showing ratchet teeth and locking teeth of the adjustable cervical collar having the pin and ratchet locking mechanism. Detailed Description of the Invention Figures 1A, IB, and 1C illustrate the adjustable cervical collar (10) having an elongated neck encircling band (12) , a chin support brace (14) , and an adjustable sternum and shoulder brace (15) with adjustment system for adjusting the height of the sternum and shoulder brace in relation to the elongated neck encircling band (12) . The elongated neck encircling band (12) is formed from a stiff, plastic sheet material such as high density polyethylene, polyvinyl chloride or other such stiff, sturdy plastic material. The elements of the cervical collar can be die cut, extruded, or prepared from molds as is conventional in the industry. For comfort soft foam pads (13) can be secured to the inner surface of this stiff plastic at various locations. The soft foam pads (13) are made of conventional soft plastic material. These soft plastic pads are secured to the stiff plastic material by any conventional securing means such as an adhesive or snap fasteners. It is preferred that these foam pads be secured by cement or other adhesive to reduce the number of parts of the cervical collar (10) . Figure 2 illustrates the elongated neck encircling band (12) is preferably of one-piece construction having a frontal portion (16) , a back portion (18) , a back side portions (20) , and a front end portion (22) . The elongated neck encircling band (12) is asymmetrical in design with the frontal portion (16) attached to, and an integral part of, the back portion (18). The frontal portion (16) is affixed to the chin support brace (14) and is placed against the front portion of a patient's neck under the patient's chin. The back portion (18) of the cervical collar (10) is generally affixed to the back of the patient's neck. The back side portion (20) and the front end portion (22) are integral elements of the neck encircling band (12) located at each end and are generally secured together after the adjustable cervical collar is secured to the patient. The frontal portion (16) , when placed flat, is generally curvilinear in design, curving downward and then generally curving back upward from the front end portion (22) to the back portion (18) with an opposite longitudinal curved edge, which runs from one side of the frontal portion to the other side. The lower curved edge (24) of the frontal portion is discontinued at that point where a cut-out section (26) , which in use overlaps the cervical collar (10) . The upper curved edge (28) of the frontal portion (16) runs roughly parallel to the lower curved edge (24) except that it is not discontinued as with the lower curved edge (24) . Secured to the upper curved edge (28) is a chin support tab (30) extending upward away from the upper curved edge (28) of the frontal portion. This chin support tab (30) is used to secure the chin support brace (14) to the frontal portion (16) of the neck encircling band (12) . Secured to one side of the frontal portion and an integral part of the cervical collar is the back portion (18) of the cervical collar (10) . The back portion (18) can be of any conventional shape from generally rectangle to generally oval. The back portion (18) of the elongated neck encircling band (12) contains a number of vertical elongated slots (32) and cooperating slits (34) to make the neck encircling band (12) more flexible. An integral part of the back portion (18) located distal from the frontal portion (16) is the back side portion (20) . A number of elongated slots (36) similar to those contained in the body of the back portion (18) can be provided in this back side portion (20) . Distal from the back side portion (20) of the elongated neck encircling band (12) is the front end portion (22) which extends out from the frontal portion (16) . It acts in concert with the back side portion (20) when the cervical collar is placed around a patient's neck. The collar retaining means can be any choice of straps or fasteners which hold the adjustable cervical collar (10) together. For example, in a preferred embodiment an elongated hook and loop fastener (40) is secured to the to the back portion (18) and the back side portion (20) of the cervical collar through selected elongated slots (36) on the back side portion (20) and also the body of the back portion. The second major element of the adjustable cervical collar is the chin support brace. As previously stated, the chin support brace can be a separate element from the elongated neck encircling band or it can be formed as one integral piece of the chin support brace, permanently secured to the elongated neck encircling band. The chin support brace can be a conventional preformed, bowed forward chin support brace or, in an alternative embodiment, the chin support brace can be adjustable and formed from two separate elements. Figures 3 and 4 illustrate two pieces of a chin support brace. The first piece is a j-shaped element (44) , and the second piece is a curved element (46) . The two pieces are constructed from the same type of stiff plastic material as is the elongated neck encircling band (12) . Single piece chin support braces (not shown) are desirable because of their simplicity and ease of operation. Additionally, a chin support piece can be mounted to either the neck encircling band or floating brace depending upon the embodiment of the adjustable cervical collar. Figure 5 illustrates an alternative embodiment of a chin support brace. This chin support piece has a hook and tab piece (68) secured to the j-shaped element (44) , which fits into a slot (70) in the second end of the curved element (46) to hold the chin support elements in a bowed forward position. Figures 6A and 6B illustrate a floating brace or sternum and shoulder brace (15) . The sternum and shoulder brace (15) is adjustably secured to the frontal portion of the elongated neck encircling band. The shape of the shoulder brace (15) is similar to the shape of the frontal portion except at the cut¬ out section (26) . The cut-out section (26) has a lower curved edge (72) of the sternum and shoulder brace (15) . The lower curved edge (72) is approximately parallel with the upper curved edge (28) of the elongated neck encircling band, but is located at the lower curved edge of the sternum and shoulder brace (15). The upper curved edge (74) of the sternum and shoulder brace is discontinued where the upper curved edge (22) of the sternum and shoulder brace (15) meets the cut-out section. The cut-out section (26) continues uninterrupted from the elongated neck encircling band (28) to the sternum and shoulder brace (15) . The cut-out section extends uninterrupted regardless of the adjustment of the height of the sternum and shoulder brace (15) in relation to the elongated neck encircling band (12) thus providing at least one aperture, which exposes the neck muscles at the level of the larynx regardless of adjustment to the height of the sternum and shoulder brace (15) . Figures 6A and 6B illustrate, on each side edge of the cut¬ out section (26) , a positive alignment tracking means. The positive alignment tracking means includes an overlap section (76) of the sternum and shoulder brace. This overlap section (76) extends over and around the side edges (78) of the frontal portion of the elongated neck encircling band which form the cut-out section (26) . This overlap section (76) is located on each side edge (78) of the cut-out section (26) such that, as the sternum and shoulder brace moves vertically upward and downward. The overlap section (76) rests against the side edges (78) of the frontal portion (16) of the elongated neck encircling band (12) . As the sternum and shoulder brace is extended downward, the overlap section rests securely against the cut-out section. This structure prevents the elongated neck encircling band (12) from twisting out of parallel alignment as the sternum and shoulder brace (15) is extended downward. Any downward movement of one side of the sternum and shoulder brace automatically results in a corresponding and parallel downward movement on the opposite side of the sternum and shoulder brace (15) . This structure assures that the sternum and shoulder brace is supported equally on both the left and the right side automatically. The back portion (18) of the elongated neck encircling band of this embodiment can be placed against the patient's neck and the sternum and shoulder brace (15) can be adjusted without moving the back portion (18) of the elongated neck encircling band (12) . The sternum and shoulder brace (15) slides up and down behind the frontal portion (16) of the elongated neck encircling band on a plurality of gliding means or posts (80) which slide or ride within reverse gliding means or slots (82) either in the body of the frontal portion (16) of the elongated encircling band or the body of the sternum and shoulder brace (15) or both. Preferably, a pair of slots (82) are provided on either side of the cut-out section (26) in the sternum and shoulder brace (15) , which operate in cooperation with a pair of posts (80) secured to the frontal portion (16) of the elongated neck encircling band on either side of the cut-out section (26) . Appropriate rivets and heads for the posts are utilized to hold the sternum and shoulder brace in place while still permitting the sliding movement of the sternum and shoulder brace (15) . Preferably, a second pair of vertical slots (84) is formed in the elongated neck encircling band closer to the cut-out section (26) than the first pair of slots. Appropriate posts with rivets and heads operate in conjunction with these slots to permit the sternum and shoulder brace (15) to move vertically in relation to the frontal portion (16) of the elongated neck encircling band. The combination of the four slots and posts operating in conjunction with the overlap sections (76) to permit the sternum and shoulder brace (15) to move smoothly and vertically in relation to the frontal portion (16) of the elongated neck encircling band. This adjustment mechanism permits an appropriate distance between the patient's sternum and shoulder and the underside of the patient's jaw at the chin to maintain support of the patient's jaw. Modifying the location of the sternum and shoulder brace (15) in relation to the elongated neck encircling band (12) on the patient, supports the patient's neck. While the location of the sternum and shoulder brace (15) can be adjusted vertically by this system of slots and posts, it is necessary that the precise location of the sternum and shoulder brace (15) in relation to the frontal portion (16) of the elongated neck encircling band (12) be fixed by a locking mechanism, which prevents the sternum and shoulder brace (15) from collapsing under pressure from the patient. This positive locking system can be any of a number of existing systems. However, preferably, a new ratchet teeth system (86) is utilized to provide this positive locking system. A groove and slot system (not shown) , which slides with friction, is an acceptable alternative embodiment. Figures 7A, 7B, and 7C illustrate an embodiment of the ratchet teeth system (86) . This embodiment permits the sternum and shoulder brace (15) of the cervical collar to be extended downwardly, but does not allow it to ascend after its extension. This type of positive locking system is quick to use and provides safety for the patient. This system has one, or preferably, a pair of rows of ratchet teeth (88) secured to the outer surface of the elongated neck encircling band. Desirably, one of each pair of rows is located on either side of the second set of slots (84) on the frontal portion (16) of the elongated neck encircling band (12) . These rows of ratchet teeth (88) are cut such that a pawl (90) located in a cover piece (92) fitting over the ratchet teeth permits only downward movement of the sternum and shoulder brace (15) . Upward movement of the sternum and shoulder brace (15) is prevented by the interaction of the pawl (90) with the ratchet teeth. The cover piece (92) , which covers and holds the pawl, can be any conventional design such that it moves in relation to the ratchet teeth in line with the movement of the sternum and shoulder brace itself. In one embodiment, the cover piece (92) is secured at its top portion to the sternum and shoulder brace (15) as an element of the post which passes through the slot (84) and at its bottom portion by a second post with a rivet and hook secured to the sternum and shoulder brace (15) . Various other arrangements can be made within the invention. This ratchet teeth system can include a second group of ratchet teeth (102) cut into the surface of the frontal portion (16) of the elongated neck encircling band (12) in a row parallel to the first set of ratchet teeth rows (88) . The direction of the cut of this second row of ratchet teeth (102) is reversed from the cut of the previously discussed ratchet teeth. This second group of ratchet teeth (102) is angled in the opposite direction from the first set of ratchet teeth. With this arrangement the cover piece (92) also contains a second pawl (104) also having teeth cut in a reversed direction from that of the first pawl (90) . This second pawl (104) can be moved into and out of alignment with the second set of ratchet teeth (102) . When the second pawl (104) and the second set of ratchet teeth (102) are aligned, movement of the sternum and shoulder brace (15) is prevented in the opposite direction from the movement prevented by the first set of ratchet teeth (88) and first pawl (90) . Preferably, when this second set of ratchet teeth (102) and second pawl (104) are engaged, they prevent the sternum and shoulder brace (15) from being further downwardly extended. If the first set of ratchet teeth (88) and the first pawl (90) are also engaged, this structure provides a complete locking system for the sternum and shoulder brace (15) and prevents both retrograde movement vertically and additional movement downward of the sternum and shoulder brace (15) . This alternative embodiment permits both sets of pawls (90 and 104) to be horizontally movable. Each pawl can be both engaged with the appropriate ratchet teeth to prevent movement in one direction and each pawl can be moved horizontally out of alignment with the corresponding ratchet teeth to permit appropriate vertical movement of the sternum and shoulder brace (15) . Pawls, that are independently movable in a horizontal direction within the cover piece (92) , have the greatest degree of adjustment capacity for the sternum and shoulder brace (15) while providing a positive locking of the sternum and shoulder brace (15) . The alternative arrangements are shown in Figures 7A, 7B, and 7C. Figure 7A illustrates the first set of ratchet teeth rows (88) aligned with the first pawl (90) . With this structure of the pawl and ratchet teeth, the sternum and shoulder brace (15) can be extended downward and closer to the patient's chest. Retrograde movement upward is prevented by the interaction of the first set of ratchet teeth (88) and the first pawl (90) . The second pawl and the second set of ratchet teeth (102) in this embodiment are not in alignment. Once the correct position of the sternum and shoulder brace is achieved for the patient, the second pawl (104) is moved in a horizontal direction until it is in alignment with the second set of ratchet teeth (102) as illustrated in Figure 7C. At this point, the sternum and shoulder brace (15) cannot move further downward or upward. Moving the first pawl (90) out of alignment with the first set of ratchet teeth rows (88) permits the sternum and shoulder brace (15) to be retracted upward as illustrated in Figure 7B. Once the precise location for the sternum and shoulder brace (15) in relation to the frontal portion (16) of the elongated neck encircling band is achieved, both pawls are placed in alignment with their respective ratchet teeth. This alignment prevents any further movement of the sternum and shoulder brace as illustrated in Figure 7C. The set of pawls are preferably arranged in a positive locking system such that they lock in alignment with the respective ratchet teeth. In one embodiment of this system, each set of pawls (90 and 104) has a tab system attached to its outside edge. The tab system assists in locking the pawls into a predetermined height after final adjustment of the location of the sternum and shoulder brace of the cervical collar. A number of different tab systems can be utilized. In one embodiment, the outside end of each pawl attaches to a tab (106) and can rotate over the cover piece (92) and lock in place to the top surface of the cover piece. These tabs only lock in position to the cover piece when the sternum and shoulder brace (15) is unable to move up nor down. In this embodiment, both sets of pawls engage both sets of ratchet teeth rows to lock the sternum and shoulder brace (15) securely in place. A pair of ratchet teeth rows in the preferred system are vertical and on both sides of one of the slots. The post holds the cover piece (92) over the locking system and is secured to the back side of the sternum and shoulder brace (15) . Preferably, the two sets of ratchet teeth rows are located one on either side of the slot (84) . These ratchet teeth (88) , when operating with the corresponding pawl (90) , permit the sternum and shoulder brace (15) to extend downward, but do not permit it to move back upward. A third row of ratchet teeth (102) is located outside of the first two rows of ratchet teeth away from the cut-out section (26) . These ratchet teeth are cut with the opposite angle from the teeth in the first two rows. This third row of ratchet teeth (102) when operating in conjunction with a cooperating reverse pawl (104) prevents further extension of the sternum and shoulder brace downward from the elongated neck encircling band. Figures 8A and 8B illustrate the preferred embodiment. Preferably, the pawl (90) is located within a slot (96) in the cover piece (92) . The cover piece (92) moves vertically in relation to the first set of ratchet teeth (88) . This structure permits the teeth (98) of the pawl to slide over the first set of ratchet teeth (88) . Figure 9 illustrates the pawl (90) located on a separate slide piece (100) and slidably secured within the cover piece (92) . The pawl (90) slides out of alignment with the first set of ratchet teeth (88) and permits the sternum and shoulder brace (15) to move upward as well as downward. Preferably, the slide piece (100) locks the teeth of the pawl (90) in place preventing vertical movement of the sternum and shoulder brace (15) after the sternum and shoulder brace (15) has been secured to the patient. This embodiment can be slidably adjusted to permit the movement of the sternum and shoulder brace (15) upward after it is removed from the patient. Figure 10 illustrates an adjustable cervical collar having locking mechanism with a locking stop means or pawl with ratchet and locking teeth (302) . A slot (301) is located in the neck encircling band. Figure 11 is a partial side view of a disengaged locking mechanism, allowing free movement of the adjustable cervical collar, and with a locking stop means in an unlocked position. The pawl with ratchet and locking teeth (302) has a ratchet and locking teeth to engage ratchet teeth of the locking mechanism. A guiding wall (303) has two racks of teeth on the lower surface. A snap ridge (304) is formed for a pawl. A sternum and shoulder brace (305) and a neck encircling band (306) have slots (307) for parallel sliding with a ratchet teeth rack (308) and a locking teeth rack (309) . Figure 12 is a partial side view of an engaged locking mechanism, not allowing free movement of the adjustable cervical collar, and with a locking stop means in a locked "safety" position. Figure 13 is a partial side view of an engaged locking mechanism, not allowing free movement of the adjustable cervical collar, and with a locking stop means in a fully locked position. A locking teeth segment (310) and a ratchet teeth segment (311) provide a positive lock to the locking mechanism when the lock stop means is closed. Figure 14 is a partial side view showing ratchet teeth and locking teeth of the adjustable cervical collar having the pin and ratchet locking mechanism. The locking stop means operates by the following method. The locking stop means is a slidable locking teeth rack that slides from an open or unlocked position to a safety position and snaps onto a ridge. The snap and ridge hold the locking stop means and prevent accidental sliding of the locking stop means. The locking mechanism is also stopped in this optional intermediate safety position. Further sliding of the locking stop means operates by closing the locking stop means in a fully locked position. This position stops all sliding of the adjustment system means. The locking stop means functions by sliding teeth into position with the ratchet teeth of the locking mechanism, sliding pins into holes of a rail and channel locking mechanism (not shown) , by pinching or wedging a rail and channel locking mechanism (not shown) , or by a similar means. The slidable locking stop means can be a slidable locking teeth rack that slides between three positions. The three positions include a first position that permits the sternum and shoulder brace to move in either of two opposite directions. A first direction increases the height of the sternum and shoulder brace in relation to the elongated neck band and a second direction decreases the height of the sternum and shoulder brace in relation to the elongated neck band. A second position permits the sternum and shoulder brace to move only in the first direction. A third position prevents the sternum and shoulder brace from moving.

Claims: Claims 1. An adjustable cervical collar comprising: (a) an elongated neck encircling band; (b) a floating brace adjustably secured to the elongated neck encircling band; (c) a chin support brace secured to a combination of the elongated neck encircling band and floating brace; (d) an adjustment system means adjustably secured to the elongated neck encircling band and to the floating brace for adjusting the height of the floating brace in relation to the elongated neck encircling band; (e) a locking mechanism for the adjustment system means, the locking mechanism has a locking stop means; and (f) a positive alignment means for maintaining the floating brace in parallel alignment with the elongated neck encircling band as the height of the floating brace is adjusted in relation to the elongated neck encircling band. 2. The adjustable cervical collar of claim 1 wherein the adjustment system means includes a ratchet teeth and pawl system. 3. The adjustable cervical collar of claim 1 wherein the adjustment system means is a pair of rows of ratchet teeth and a pair of pawls acting in cooperation with the rows of ratchet teeth. 4. The adjustable cervical collar of claim 2 wherein the adjustment system means also includes a set of reverse ratchet teeth and a reverse pawl. 5. The adjustable cervical collar of claim 4 wherein the reverse pawl is lockable in a position over the reverse ratchet teeth to prevent downward movement of the sternum and shoulder brace. 6. The adjustable cervical collar of claim 1 wherein the chin support brace is a single preformed piece. 7. The adjustable cervical collar of claim 1 wherein the elongated neck encircling band is comprised of a frontal portion, a back portion, a frontal end portion and a backside portion, the sternum and shoulder brace is adjustably secured to the frontal portion of the neck encircling band, and the floating brace is a sternum and shoulder brace, the sternum shoulder brace is adjustably secured behind the frontal portion. 8. The adjustable cervical collar of claim 7 wherein the adjustment locking system is comprised of a row of ratchet teeth, a pawl adjustably secured to a cover piece which is secured to the sternum and shoulder brace, a set of reverse teeth and a reverse pawl adjustably secured to the cover piece. 9. The adjustable cervical collar of claim 8 wherein the pawl and the reverse pawl are independently secured to tabs, each of which can be independently locked in position to the cover piece, wherein the tabs are locked in position to prevent vertical movement of the sternum and shoulder brace in relation to the elongated neck encircling band. 10. The adjustable cervical collar of claim 9 wherein the locking mechanism for the ratchet teeth and pawl system includes a slidable locking teeth rack. 11. The adjustable cervical collar of claim 10 wherein the slidable locking teeth rack slides between three positions, the three positions are: a first position permitting the sternum and shoulder brace to move in either of two opposite directions, a first direction increasing the height of the sternum and shoulder brace in relation to the elongated neck band and a second direction decreasing the height of the sternum and shoulder brace in relation to the elongated neck band; a second position permitting the sternum and shoulder brace to move only in the first direction; and a third position preventing the sternum and shoulder brace from moving. 12. The adjustable cervical collar of claim 11 wherein the slidable locking teeth rack has engagable means being engagable with a flexible overlap section to removably lock the slidable locking teeth rack in each of the three positions.

Inventors: KOHNKE OLE, MARTIN WILLIAM, KOHNKE, OLE, MARTIN, WILLIAM
Applicants: AMBU INC, AMBU INC.
Application year: 1996
Main classification: A61F5
IPC codes: A61F5