Single-use injector having a flexurally elastic housing
A housing of the injector is made from a thin-walled sheet-metal part. The sheet-metal part has at least two branches or legs. Each branch has, at the free end thereof, an angled retaining element or a recess as a means of receiving the cylinder of a cylinder/piston unit. The branches are elastic flexural beams which, in the middle area, are each bent in a Z-shape or S-shape to form a supporting portion for the piston-actuating ram. The contact zone situated between an individual supporting portion and the piston-actuating ram represents a wedge gear pairing that forces the respective branch outwards. The trigger unit comprises at least a trigger element which is slidably supported on the metal sheet, wherein the support section or, respectively the contact sections extend outwardly into longitudinal grooves. The branches may be provided with a locking tongue to engage corresponding openings in the trigger element to lock the housing in position as desired.
1. In combination with a disposable injector with a housing ( 200 ) in which or on which are arranged, in each case at least in some areas, at least one mechanical spring energy reservoir ( 50 ), at least one cylinder/piston unit ( 100 ) that can be filled at least temporarily with active substance, at least one piston-actuating ram ( 60 ) and at least one trigger unit ( 80 ),
the piston-actuating ram ( 60 ) is positioned between the spring energy reservoir ( 50 ) and the piston ( 111 ) of the cylinder/piston unit ( 100 ) including a cylinder ( 101 ),
the spring energy reservoir comprises at least one pretensioned spring element ( 50 ), and
the spring-loaded piston-actuating ram ( 60 ) is supported on the housing ( 200 ) in a releasable manner, the improvement which comprises:
the housing ( 200 ) is made from a thin-walled sheet-metal part ( 201 ),
the sheet-metal part ( 201 ) has at least two branches ( 220 ),
the branches ( 220 ) each have, at the free ends thereof, an angled retaining element ( 221 ) or a recess as a means of receiving the cylinder ( 101 ) of the cylinder/piston unit ( 100 ),
the branches ( 220 ) are elastic flexural beams which, in the middle area, are each bent in a Z-shape or S-shape to form a supporting portion ( 231 ) for the piston-actuating ram ( 60 ), each supporting portion ( 231 ) is adjoined by a bearing portion ( 232 ),
a contact zone situated between the individual supporting portion ( 231 ) and the piston-actuating ram ( 60 ) represents a wedge gear pairing that forces the respective branch ( 220 ) outwards, and
the trigger unit ( 80 ) comprises at least a trigger element ( 82 ) which is slidably supported on the metal sheet part ( 201 ), wherein the support portion ( 231 ) or, respectively the bearing portions ( 232 ) extend outwardly into rear longitudinal grooves ( 83 )
at least one locking tongue ( 190 ) arranged on the at least two branches ( 220 ), the at least one trigger unit ( 82 ) having corresponding openings to received the at least one locking tongue ( 190 ) for locking the housing ( 200 ) in predetermined position.
2. Disposable injector according to claim 1 , wherein the housing ( 200 ) is made from a sheet-metal strip ( 201 ), and the sheet-metal strip ( 201 ) is bent in a U-shape to form two branches ( 220 ).
3. Disposable injector according to claim 1 , wherein the sheet-metal strip ( 201 ) has, at both free ends, inwardly angled retaining elements ( 221 ) as a bearing for the piston-actuating ram ( 60 ).
4. Disposable injector according to claim 1 , wherein the branches ( 220 ) are at least five times longer than the width of the branches.
5. Disposable injector according to claim 1 , wherein the supporting portion ( 231 ) encloses an angle of 115±2 degrees with the portion ( 233 ) that carries the respective retaining element ( 221 ).
6. Disposable injector according to claim 1 , wherein the supporting portion ( 231 ) encloses an angle of 113±2 degrees with the portion ( 232 ) on which the spring element ( 50 ) laterally bears when the injector is tensioned.
7. Disposable injector according to claim 1 , wherein the sheet-metal part ( 201 ) is made from a spring steel.
8. Disposable injector according to claim 1 , wherein the trigger element ( 82 ) is a trigger tube surrounding the sheet-metal part ( 201 ).
9. Disposable injector according to claim 1 , wherein the piston-actuating ram ( 60 ) is a flat plate ( 73 ) with a rectangular surface area or is made from a sheet-metal strip ( 73 , 78 ) bent in a U-shape.
10. Disposable injector according to claim 1 , wherein the trigger element ( 82 ), in combination with the housing ( 200 ) and with a tear-off banderole ( 90 ) secured thereon, forms a trigger unit ( 80 ).
11. Disposable injector according to claim 1 , further comprising at least one locking tongue ( 190 ) arranged on the at least two branches ( 220 ), the at least one trigger unit ( 82 ) having corresponding openings to received the at least one locking tongue ( 190 ) for locking the housing ( 200 ) in predetermined position.
12. Disposable injector according to claim 11 , wherein the at least one locking tongue ( 190 ) is formed by a U-shaped cut out gap ( 197 ) in the at least two branches ( 220 ).
13. Disposable injector according to claim 12 , wherein the gap ( 197 ) ends in bores ( 198 ).
14. Disposable injector according to claim 11 , wherein the least one locking tongue ( 190 ) is curved several times.
15. Disposable injector according to claim 11 , wherein the at least one locking tongue ( 190 ) is composed of a resiliently outwardly deflecting portion ( 191 ) and a supporting portion ( 192 ).
16. Disposable injector according to claim 15 , wherein the supporting portion ( 192 ) has a locking knob ( 193 ) proximate the centre thereof and a supporting end face ( 194 ).
17. Disposable injector according to claim 16 , wherein the trigger element ( 82 ) has a locking bore ( 26 ) and a locking window ( 25 ) in predetermined position for engaging the supporting portion ( 192 ).
18. Disposable injector according to claim 1 , wherein the at least two branches ( 220 ) each include a locking niche ( 234 ) and a wave-shaped guide bulge ( 235 ).
19. Disposable injector according to claim 18 , wherein the at least one trigger element ( 82 ) further includes front longitudinal grooves ( 23 ) and a web ( 81 ) positioned between the rear longitudinal grooves ( 83 ) and the front longitudinal grooves ( 23 ), the locking niche ( 234 ) for engaging the web ( 81 ) upon triggering of the injector.
20. Disposable injector according to claim 19 , wherein the retaining elements ( 221 ) in operative engagement with the cylinder ( 101 ), the wave-shaped guide bulge ( 235 ) positioned in close proximity to the retaining elements ( 221 ) for supporting the branches ( 220 ).