Abstract:
The invention concerns a tamper-evident padlock and padlock combination. The padlock ( 10 ) has a moulded plastics lock body ( 14 ) which includes an open-ended passage ( 22 ) and an opening ( 26 ) spaced from the passage. There is also a hasp ( 16 ) which has first and second spaced apart legs ( 32, 34 ). An end ( 32.1 ) of the first leg can be located in the passage through a first end thereof while the end of the second leg can be located simultaneously in the opening. The end of the first leg in the passage can then be engaged by a breakable seal ( 20 ) which is inserted into the passage through the opposite end of the passage, in order to lock the hasp relative to the lock body. The padlock combination ( 12 ) comprises the padlock ( 10 ) and the seal ( 20 ) in combination.

Description:
This is a 371 filing of International Patent Application No. PCT/IB2003/002821 filed Jul. 16, 2003 and published on Feb. 26, 2004 under publication number WO 2004/017280 A and claims priority benefits from South African Patent Application No. 2002/6585 filed Aug. 16, 2002. 
   BACKGROUND TO THE INVENTION 
   THIS invention relates to a padlock. 
   A known padlock marketed under the name ENVOSEAL has a lock body of multi-part, moulded plastics construction and a metal hasp which is generally U-shaped. A first leg of the hasp is held captive in the lock body in such a manner that the hasp can pivot and slide relative to the lock body between respective open and closed positions. When the hasp is in a closed position the end of its second leg locates in an opening in the lock body and a transverse hole in the first leg aligns with a transverse hole in the lock body. A frangible plastic seal is clipped to the lock body such that a part of the seal locates in the aligned holes. This prevents pivotal movement of the hasp from the closed to the open position until such time as the seal is broken and removed. Breakage of the seal Indicates that the lock has been tampered with. 
   Padlocks of this kind are used in many different applications where a tamper-evident seal is required. One example is in airline trolleys used to store duty free goods, alcoholic beverages and the like. Typically, the padlock in such an application is used to lock the door or drawer of the trolley in a closed position. 
   A drawback of the known padlock described above is that it is expensive to manufacture, partly because individually moulded plastic components have to be assembled about the metal hasp and then connected to one another to hold the hasp leg captive. Another drawback is that the design of the padlock dictates that it must have a fairly substantial thickness. For economy of space and packing airline trolleys have a recess to receive the installed lock but this is often too shallow to accommodate the known lock fully. As a result the lock projects from the trolley and can either present an obstruction or itself be impacted on and possibly damaged. 
   SUMMARY OF THE INVENTION 
   According to the invention there is provided a padlock comprising:
         a moulded plastics lock body having therein an open-ended passage and an opening spaced from the passage; and   a hasp which has first and second spaced apart legs, an end of the first leg being locatable in the passage through a first end thereof and an end of the second leg being locatable simultaneously in the opening, the end of the first leg in the passage being engagable by a breakable seal inserted into the passage through an opposite, second end thereof to lock the hasp relative to the lock body.       

   Preferably the lock body is of one-piece, moulded plastics construction nad has a thickness of 8 mm or less. The hasp may be attached to the lock body by a cord or the like. Alterantively it may be attached to the lock body, typically by means of a rivet, in a manner allowing sliding and pivotal movement of the hasp relative to the lock body. 
   Other features of the padlock of the invention are set forth in the accompanying description and the appended claims. 
   According to another aspect of the invention there is provided a padlock combination comprising the padlock summarised above and a breakable seal having an insertion portion which can be engaged, by movement of the seal through the second end of the passage, with the end of the first leg of the hasp when this end is located in the passage, thereby to lock the hasp relative to the lock body. 
   Other features of the padlock combination are also set forth in the accompanying description and the appended claims. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will now be described in more detail, by way of example only, with reference to the accompanying drawings in which: 
       FIG. 1  illustrates a padlock and padlock combination according to a first embodiment of the invention in an unlocked condition; 
       FIG. 2  illustrates the same padlock and combination in a locked condition; 
       FIG. 3  shows a cross-sectional view of the padlock combination of  FIG. 1  in the locked condition; 
       FIG. 4  shows a cross-section at the line  4 — 4  in  FIG. 3 ; 
       FIG. 5  shows a perspective view of the seal of the padlock combination of  FIG. 1 ; 
       FIG. 6  shows a cross-section at the line  6 — 6  in  FIG. 5 ; 
       FIG. 7  shows a perspective view of a padlock combination according to a second embodiment of the invention in a locked condition; 
       FIG. 8  shows a cross-sectional view of the second embodiment; and 
       FIG. 9  shows, in a cross-sectional view, the movement of the hasp in a cross-sectional view. 
   

   DESCRIPTION OF PREFERRED EMBODIMENTS 
     FIG. 1  illustrates a padlock  10  and a padlock combination  12  according to a first embodiment of the present invention. The padlock  10  consists of a lock body  14  and a hasp  16 . The padlock combination  12  consists of the padlock  10  and a seal  20 . 
   The lock body  14  is a one-piece plastics moulding. It has a passage  22  extending through it from one open end  23  to an opposite open end  25 . There is a shoulder  24  adjacent the mouth of the passage at the open end  25 , which opens into a generally rectangular recess  27 . The lock body  14  also has a blind opening  26  spaced from and parallel to the passage. Relatively large and relatively small holes  28  and  30  respectively extend tranversely through the lock body 
   The hasp  16  is of 2 mm thick flat mild steel and has the shape seen in  FIG. 1 . It is generally of U-shape with first and second legs  32  and  34  respectively, the leg  32  being somewhat longer than the leg  32 . The end  34 . 1  of the leg  34  is dimensioned to be a snug slide fit in the blind opening  26 . The end  32 . 1  of the leg  32  is enlarged and is a slide fit in the passage  22 . It includes shoulders  32 . 2  and is formed with a cavity  36  which is undercut by virtue of opposing, re-entrant, inclined tabs  38 . The tabs  38  have inclined outer surfaces  38 . 1  and similarly inclined inner surfaces  38 . 2 . 
   The seal  20 , which, together with the padlock  10 , makes up the padlock combination  12  of the invention, is made as a one-piece plastics moulding. It includes a tab portion  20 . 1  from which an insertion portion  20 . 2  projects. The insertion portion has a central stem  20 . 3  and resilient arms  20 . 4  which project rearwardly from the end of the stem. 
   In order to close the padlock, the hasp  16  is aligned with the lock body  14  as shown in  FIG. 1 . The hasp and lock body are then moved relative to one another so that the legs  32  and  34  enter and slide into the passage  22  and opening  26  respectively. When the hasp is fully inserted the end  34 . 1  of the leg  34  abuts the blind end of the opening  26 , the shoulders  32 . 2  on the hasp abut the mouth of the passage at the open end  23  and the end of the leg  32  abuts the shoulder  24 , as shown in  FIG. 2 . 
   In order to seal the lock the seal  20  is positioned in the recess  27  and is slid, in direction opposite to that in which the hasp is inserted, into the opposite end  25  of the passage  22 . When the arms  20 . 4  of the insertion portion  20 . 2  encounter the tabs  38  they are inwardly deflected. When the insertion portion is fully inserted the arms move past the tabs and thereafter, with the insertion portion fully located in the cavity  36 , spring back to locate behind the tabs, i.e. the extremities of the legs  20 . 4  of the insertion portion  20 . 2  locate behind the tabs  38 . 
   The insertion portion is accordingly clipped into the cavity  36  in the passage  22 , with the tab portion  20 . 1  lying flat in the recess  27 . It will be understood that the seal cannot be withdrawn by a sliding action, because this would merely draw the extremities of the legs  20 . 4  against the inner inclined surfaces  38 . 2  of the tabs  38 . Thus, with the insertion portion  20 . 2  of the seal clipped into the cavity  36  inside the passage  22 , the hasp is effectively locked to the lock body. In order to open the padlock, it is necessary to break the seal  20 . 
   This is achieved by bending the tab  20 . 1  in a direction out of the recess  27 , as indicated in  FIG. 4  by the arrow  44 , so that the seal breaks at a zone of reduced thickness  20 . 5  between the tab and insertion portions. Once the tab has been broken off, the hasp can be withdrawn from the lock body and the insertion portion can be removed from the cavity  36 . 
   Referring to  FIGS. 5 and 6  it will be seen that the tab  20 . 1  forms a recessed, upstanding wall  20 . 6  adjacent the root of the stem  20 . 3 . When the insertion portion  20 . 2  of the seal is clipped into the cavity  36 , the wall recess receives portions of the tabs  38  so that the wall lies closely adjacent those tabs. With this feature it is difficult if not impossible to insert a sharp tool past the tab  20 . 1  and into the passage  22  in order to unclip the insertion portion  20 . 2  from the cavity  36 , thereby improving the integrity of the seal. 
   In an application of the padlock and padlock combination to, for instance, an airline trolley, the hasp will be arranged in the normal way to pass through openings in the components of the trolley which are to be locked to one another, eg the frame of the trolley and a door or drawer. It will also be understood that in such applications, a visual inspection of the seal to ensure that it is not broken provides an assurance that the trolley has not been opened without authorisation prior to being brought onto the aircraft. 
   The large hole  28  provides a suspension point at which the padlock, once unlocked, can be suspended from a hook or the like for re-use at a later stage with a new seal  20 . 
   The hasp  16  is formed with a small hole  50 . This hole and the small hole  30  in the lock body provide attachment points for the ends of a thin cord  52  which serves to attach the hasp to the lock body, to prevent inadvertant loss of the hasp. 
     FIGS. 7 to 9  illustrate a second embodiment of the invention which does away with the need for a cord  52  to attach the hasp to the lock body. In these Figures, components corresponding to those illustrated in  FIGS. 1 to 6  are indicated with the same reference numerals. 
   In this embodiment, the hasp  16  is permanently attached, in a manner allowing both sliding and pivotal movement, to the lock body  14 . This is achieved by means of a rivet  60  which passes through the lock body, in the passage  22 , and through an elongate slot  62  in the end  32 . 1  of the leg  32  of the hasp. It will also be noted that the side  64  of the lock body is laterally extended and provides a shoulder  66  adjacent the rivet  60 , and that there is only a single shoulder  32 . 2 . 
     FIGS. 7 and 8  show the second embodiment in a closed and locked condition. As in the first embodiment, the legs  32 . 1  and  32 . 2  are located in the passage  22  and blind opening  26 , and the insertion portion  20 . 2  of the seal  20  is clipped into the cavity  36 , inside the passage  22 , with the tab portion  20 . 1  of the seal lying flat in the recess  27 . As before it will be understood that the hasp is effectively locked to the lock body by the seal when the padlock combination is in this locked condition. 
   It will also be noted that in the locked position, the rivet  60  is situated at the outer end of the slot  62 . 
   In order to open the padlock, the seal  20  is broken by bending the tab portion  20 . 1  in a direction out of the recess. Once the tab portion has been broken away from the insertion portion, the hasp can be slid outwardly as shown in full lines in  FIG. 9 . The rivet  60  slides along the slot  62  to its inner end as illustrated. At this stage the insertion portion  20 . 2  of the seal is still retained in the cavity  36 . When the rivet has reached the end of its travel in the slot, the hasp can be pivoted to the broken line position in  FIG. 9 , allowing the insertion portion  20 . 2  of the seal to fall out of, or be removed from, the cavity  36 . Abutment of the side of the hasp with the shoulder  66  prevents further pivotal movement of the hasp. 
   In order to re-lock the padlock, the opposite procedure is followed, i.e. the hasp is pivoted to the full line position in  FIG. 9  and is then slid inwardly to the  FIG. 8  position, whereafter a fresh seal  20  can be clipped into place. 
   In both embodiments, the inclination of the tabs  38  is a security feature. The tabs and the upstanding wall  20 . 6  of the seal  20  are so designed that the tabs extend into the recess as will be apparent from  FIGS. 2 and 7 . The tabs accordingly provide some security against insertion of a sharp tool into the passage  22  with the intention of unclipping the legs  20 . 4  of the seal.