GB2100045A - Automatic advertisement display - Google Patents

Abstract

An automatic advertisement display apparatus provides the sequential display control functions which permit a number of succeeding display panels 7 to be presented two times in different positions on the display side sequentially. The apparatus includes a lateral transport means which comprises front and rear carriers 8, 8a reciprocated by a belt 3, and a transversal transport means which comprises guides 14, 14a, 15, 15a, rotary push forward cams 17, 17a, 18, 18a and rotary hook lift cams 19, 19a, 20, 20a on the carrier on each side simultaneously to be transferred to the carrier on the opposite side. The transversal transport means also provides the function of placing the succeeding display panels in the wait condition. Those sequential display operations are performed by a sequence controller. <IMAGE>

Description

SPECIFICATION Advertisement display apparatus Field of the invention The present invention relates generally to an automatic display apparatus which present commercial advertisement objects. More particularly, the automatic display apparatus provides the sequential display control functions which permit a number of succeeding individual display panels or frames to be presented on the display side one after another in the sequence in which they are mounted. Each of the individual display panels in placed on the display side two times in different positions while the other succeeding display are placed in the wait condition behind the display side.A lateral transport means is included to permit at least two display panels to be carried in parallel in opposite directions on the front display side and rear side, and a transversal transport means is included to permit a display member on each side to be transferred from one side to the other side. Each of the individual display panels is formed to a rectangular shape and size, carrying intelligent information represented by characters or letters, graphics, ornamental patterns or designs, or any combination thereof. The display panels can be replaced by new ones whenever the need arises after a certain period of time during which the existing display panels have been presented.The presentation of the display panels is sequentially controlled such that each succeeding display panel appears and then disappears, and continues in this manner until the existing display panels are finally replaced by new ones. In a varied form of the present invention, the apparatus can accommodate a great number of display panels, and therefore a variety of advertisements can be presented-in a single unit or a combination of several units. This provides an extended-time presentation of the same display panels that have been mounted.

Description of the prior art The commercial advertisement devices of the type which present the successive display panels in the sequential rotation have been known in the prior art technology. There are various constructions which have already been applied for practical uses. One example is the device which employs an endless film as an advertisement media, each frame carrying appropriate photographed information to be traveling in succession at regular time intervals for the pesentation. Another example is the construction that employs an endless belt carrying a plurality of successive individual display panels to travel around at regulartime intervals.In another example, the device incluces a ribbon or belt carrying a succession of appropriate information, which is initially wound on either side and then can be drawn out from one side to the other side that the information can be presented sequentially. As a primitive method of presenting the information to be displayed, the display panels or boards carrying the information are individually placed in their respective positions on the fixed display site and are eventually replaced by new ones whenever necessary, which is done all by hand. Usually, still sign boards which remain stationary in their respective positions on the display site do not attract the viewers' attention.The advertising method in which the individual display panels are periodically changing from one to another, on the other hand, can actualiy attract the attention of the viewers, but this method requires a great number of display panels in one installation in order to make the changing advertisement effective.

This type of advertisement method not only imposes the restrictions on the site of the installation but also requires an increased installation cost. For the display method employing the endless film, the presentation of the photographs or pictures carried on the film requires a projector which presents them bright on an enlarged scale on the display screen so that they can be recognized by and attractive to the viewers. The use of the projector has another problem in which the enclosure must be built deeply enough to accommodate the projector, thus restricting the choice of the site of the installation. For the method of the advertisement in which the individual display panels are manually replaced at periodic times, such as for example every thirty minutes, a considerable human labor is involved for replacement work.Such frequent replacement is not preferable in terms of the iabor economy, since it must be done in a limited period of time, costing highly. In this case, a great care must also be taken so that new display panels may be placed in their proper positions for each replacement. This results in restricting the choice of the manner and site of the display.

Summary of the invention In view of the problems of the above cited display devices and methods of the prior art, one object of the present invention is to provide an improved advertisement display apparatus which has an easy maintenance, simple, and error-free construction, and permits the succeeding individual display panels formed to rectangular shapes to be presented sequentially and two times in different positions on the display side. The change in the. position of the display panel is done in the same posture, or almost upright. The sequential display of the succeeding display panels can be such that at least two display panels are always placed on the display side, followed by another succeeding display panel which is appearing after one of the displayed panels is disappearing behind the display side at the end of one display cycle.One display panel can be presented two times in different positions until it disappear behind the display side. The movement of the individual display panels which are to be presented and disappear repeatedly is accomplished by combined lateral and transversal transports. The transversal transport device includes two pairs of slanted guide plates, one pair of which causes the display panels to travel transversely from the front side to the rear side, and the other pair of which causes the display panels to travel transversely from the rear side to the front side.The lateral transport device includes a drive belt arranged in a generally rectangular shape in plane and guide pulleys sup porting the belt at four corners, the drive belt having the two parallel longitudinal sides running on the front and rear sides and reciprocating in both directions such that one run side travels in one direction while the other run side travels in the opposite direction.

Another object of the present invention is to provide a novel concept apparatus that has solved all the problems of the prior art.

The constructional features of the present invention may be summarized as follows. Two parallel guide rails are provided in spaced relationships, one running longitudinally along the front side and the other running longitudinally along the rear side opposite the front side. A drive belt is arranged in a generally rectangular shape in a horizontal plane between the two guide rails, and has two parallel sides one of which runs along one guide rail on one side and reciprocates in both directions and the other of which runs along the other guide rail on the opposite side. The reciprocating travel of the two belt sides occurs in the oposite directions to each other when the belt is driven. The belt threads around the four guide pu lieys at four corners, forming a rectangular shape in a horizontal plane as described above.Each of the opposite parallel sides of the belt has a carrier secured thereto for conveying a display panel longitudinally from one side to the other. Each of the carriers includes a support plate secured by means of an intermediate frame to wheels which engage the guide rail, and a pair of hook locking members extending downwardly from the support plate. Each of the display panels has an upper horizontal rod and a lower horizontal rod between which a thin sheet is placed to provide an advertisement display face which carries appropriate information. The upper rod has rollers rotatably mounted to the opposite ends thereof.The transversal transport device includes two pairs of guide plates, each pair on each of the left- and right-sides of the guide rails, which provides a bridge passage that allows a display panel to travel from the guide rail on one side (front or rear) to the guide rail on the opposite side (rear or front). The rollers of the display panel rest on the parallel guide plate pair, and are capable of roiling movement down the guide plates. One pair of the guide plates is down-slanted in one direction, for example from the front side toward the rear side, and the pair is down-slanted in the other direction, for example from the rear side toward the front side; each pair is so down-slanted that a display member placed at the up side (higher level) of the guide plate bridge can be allowed to travel down to the down side (lower level) by its own weight when it is released from the carrier.For both the guide plate pairs, the degree in which the guide plate passage is to be down-slanted should preferably be in the range of 10 to 20 , although it may depend upon the diameter of the rollers, its resistance to the weight of the display panel, its surface condition, and other factors. Each pair of the guide plates includes a push-forward device which pushes a display panel forward and then detaches it away from the hook locking member, and a lift-up device which causes a display panel to be lifted and then engage the hook locking member. The push-forward device includes a set of two push cams located on the up side of the guide plate passage, which provides the function of pushing the display panel forward away from the carrier on one side toward the guide plate passage.The lift-up device includes a set of two hook lift cams located on the down side of the guide plate passage, which provides the function of lifting the display panel up so that it can engage the hook locking member on the carrier on the opposite side. The operation of the two pushforward devices on the opposite sides is synchronized so that they can operate simultaneously, and the operation of the two lift-up devices on the opposite sides is also synchronized so that they can operate simultaneously. The travel of the display member from one side to the opposite side can thus be done smoothly without any prejudice, and the disengaging and engaging of the display panel from and with the hook locking members are helped by the push-forward device and lift-up device.As such, there is no traveling problem even if the hook locking members on the back of the respective carriers, on which a display member rests by means of its rollers, are made of the same height. Also, this smooth travel of the display panel can effectively be achieved even if the slant of the guide plate passage is small, provided it is such that the display panel can be allowed to travel or slide down along the guide plate passage freely by itself.

Another object of the present invention is to provide possibilities for a combination of two or more units. If two or more units are installed on the same site, it is possible to present at least four display panels at one time in the manner described above. All display panels to be used in this application are built to meet the identical physical dimensional requirements.

The presentation of the individual display panels on the display side occurs at regular time intervals, such thatforone unit two display panels are always placed on the display side during each succeeding display cycle. The cycle at which the succeeding display panels are to be presented, changing from one to another, depends upon the number of the mounted display panels and the period of time during which the display panels are to be placed on the display side. The distinguished features of the present invention are the lateral and transversal transports of the display panels. The changing of the display panels from one to another is done so continually that two display panels from one to another is done so continually that two display panels are always placed on the front side at any time, and therefore the viewers do not feel the display unnatural. After a given display panel has been presented in two different positions on the display side, it is moved transversely to disappear behind the display side, while a next succeeding display panel which has been waiting is appearing in the first position on the display side. The means that during the transversal transport and lateral transport of the display panel behind the display side, the display panels can be stored temporariiy until next time the same display panels are again presented on the display side. This also eliminates the need of providing a particular site or enclosure for storing the display members temporarily or permanently.

Still another object of the present invention is to provide both motionless and changing presentation of the display panels. This has the effect of attracting and focusing the viewers' attention to and on the presented display panels, enhancing the advertising effect.

The above described sequential and synchronized operation of the associated mechanical elements is performed by the sequence controller which includes limit switches, relays, and timers.

Brief description of the drawings Those and other objects of the present invention will become apparent from the following description of the preferred embodiments shown in the accompanying drawings, in which: Figure 1 is a schematic diagram illustrating how the individual display panels are to be presented sequentially on the front display side in two sets of the unit according to one preferred embodiment of the present invention; Figure 2 is a plan view showing the arrangement of the succeeding individual display panels in the embodiment of Figure 1 and the sequence in which the display panels are to be presented on the display side; Figure 3 is an enlarged perspective view illustrating the internal parts or elements of a unit in the embodiment of Figure 1;; Figure 4 is a front view of another preferred embodiment of the present invention in which one set of two display panels is to be presented on the display side; Figure 5 is a front view of the embodiment of Figure 4, showing the display panels are being moved at a given time, with one display panel on the right-hand side being partly disappearing behind the front display side, the following display panel being moved to the right-hand side, and another following display panel being partly appearing on the left-hand side of the front display side; Figure 6 is a rear side view of Figure 5; Figure 7 is a cross section view of still another preferred embodiment of the present invention, in which a great number of display panels are mounted in a unit; Figure 8 is a partly enlarged side elevation of Figure 7; and Figure 9 is a longitudinal section plan view showing part of the internal mechanical arrangement.

Detailed description of the preferred embodiments The several preferred embodiments of the present invention shown in the accompanying drawings are now described in full detail. In one preferred embodiment shown in Figure 7, a casing or enclosure 1 is included. The casing 1 has a front side which is usually a display side and a rear side. Two parallel guide rails 2 and 2a are provided in the form of a channel, one on the front side and the other on the rear side. The guide rails 2 and 2a extend longitudinally in a parallelly spaced relation to each other. A drive belt 3 is arranged in a generally rectangular shape in a horizontal plane between the two guide rails 2 and 2a.The drive belt 3 has two parallel sides or runs which reciprocate in both directions; when the belt 3 is driven so that its one side can travel in one direction, its other side opposite to the one side can simultaneously travel in the opposite direction.

Four guide pulleys 4, 4a, 4b and 4c are mounted at four corners, around which the belt 3 is threaded.

One of the guide pulleys, which is indicated by 4c in Figure 3, is also a drive pulley connected through reduction gears 24 to a reversible motor 28. As shown, a carrier 8 is rigidly secured to the belt 3 on the front side, and a carrier 8a is rigidly secured to the belt 3 on the rear side. The carriers 8, 8a on each side of the belt 3 are placed in their diagnostically opposed positions when they are at rest on either of the right and left extremities of the travel. In Figure 3, the carrier 8 on the front side is shown in its rightmost side while the carrier 8a is shown in its leftmost side.Each of the carriers 8 and 8a carries a display panel 7, and includes two wheels 10 or 10a travelably engaging the guide rail 2 or 2a, a support member 9 or 9a fixed to the wheels 10 or 10a, and a hooked bracket 11 or 11a whose top is rigidly secured to the lower portion of the support member 9 or 9a. The hooked bracket 11 or 11 has a hooked portion at the bottom which extends outwardly with an upward slant. The bottom hooked portion ofthe bracket 11 or 11 a is preferably covered with a rubber sheet 12 or 12a on the upper face thereof. The rubber sheet 12 or 12a is effective in preventing the occurrence of noices that may arise as the display panel 7 is transferred onto the bracket 11 or 1 Ia as described later.Each of the individual display panels 7 is formed to appropriate shape and size, which in this case is generally rectangular. Structurally, the display panel 7 includes an upper horizontal rod 7a and a lower horizontal rod 7b, between which a thin sheet 7c is mounted to provide a display face. The upper rod 7a has a pair of rollers 13 rotatably mounted to the opposite ends thereof. A transversed transport means is provided at each of the right and left sides of the parallel guide rails 2 and 2a, bridging between the guide rails opposite each other. The transversal transport means on each side includes a pair of guide plates 14, 14a or 15, 15a which provides a passage on which the rollers 13 of the display panel 7 rest and travel rollingly. The guide plates in each pair are spaced parallelly and has a width equal to the width of the rollers 13.The guide plate pair 14, 14a shown on the right side in Figure 3 is downsloped toward the guide rail 2a on the rear side, and the guide rail pair 15, 15a on the left side is down-sloped toward the guide rail 2 on the front side. As particularly shown in Figures 7 to 9, above the higher side of each of the guide passages 14, 14a and 15, 1 5a is disposed a rotary shaft 16 or 16a extending across the respective guide passages.

Each of the rotary shafts 16 and 16a carries a pair of push-forward cams 17, 17a or 18, 18a which provides the function of releasing a display panel 7 from the hooked locking members 11 or 11 a on the carrier 8 or 8a. The releasing action provided by the push-forward cam pair is done such that it pushes the display panel 7 forward, thus causing its rollers 13 to be disengaged from the hooked portion of the locking bracket 11 or 11 a. Also, a rotary shaft 1 6b or 1 6c is disposed above the lower side of each of the guide plate pairs 14, 14a and 15, 15a, extending across the respective guide plate pair.Each of the rotary shafts 1 6b and 1 6c carries a pair of hook lift cams 19, 1 9a or 20, 20a which provides the function of engaging the rollers 13 of a display panel 7 with the bottom hooked portion of the respective locking bracket 11 or 11 a. That is, the hook lift cam pair causes the display panel 7 to be moved away from the guide passage, lifting it to permit its rollers to rest on the bottom hook. One end of each of the rotary shafts 16b and 16c are connected with a drive motor 21 or 21a, and has a pulley 22 or 22a which is connected via an intermediate belt 23 or 23a to a pulley 22b or 22c carried on a rotary shaft 16 or 16a.

As described earlier, one of the guide pulleys, shown at 4c, is rigidly secured to output shaft of reduction gears 24, and the guide rails 2 and 2a have a channel form in cross-section. Each of the carriers 8 and 8a has a pair of peripherally grooved wheels 10 and 10a which engage the guide rail 2 or 2a. Thus, the carriers 8 and 8a can travel with stability without causing a swayorfluctuation in either of the horizontal and vertical directions. In order to prevent a sidewise sway or fluctuation of each carrier in particular, a side retaining roller 26 may preferably be provided by way of a mounting arm member 25 below the guide rail 2 and 2a (Figure 8).As shown in Figure 5, a pair of guide members 27 is disposed above each of the guide passages 14, 14a or 15, 15a so that the rollers 13 of the display panel 7 can travel down rollingly without causing the display panel to sway up and down. In Figures 3 and 9, reference numeral 28 designates a reversible motor which connects with the reduction gears 24. The reciprocating travel of the belt 3 and the operations of the cam assemblies 17, 17a, 18, 1Ba and 19, 19a, 20, 20a are all controlled buy a sequence controller which includes limit switches, relays, and timers.As particu larly viewed from Figure 7, limit switches 45 are provided at the rightmost and leftmost extremities of the reciprocating travel of thwe carrier on the rear side guide rail. The limit switches provide the function of being stoppers which restrict the range of the reciprocating travel of the carriers 8 and 8a. The start and stop of the alternate reciprocating operation of the belt and the associated cam operations are controlled by a combination of those limit switches and timers (not shown).

In Figure 3, it is shown that a single unit is employed in an application in which two display panels are always to be presented at any time on the display side. Figures 1 and 2 show on application in which two units are installed in which four display panels are always to be presented at any time.

Referring them to Figures 1 and 2, the operation of the apparatus whose construction has been illustrated is described. Figures 1 and 2 simply illustrate how the display panels are sequentially moving and changing from one to another, with four display panels being presented at any given time. Ten display panels in total are shown in Figure 2, with five display panels mounted in each unit. It is assumed that all the display panels are initially placed in their respective positions as shown in Figure 2, with four display panels A, A', B, and B' being currently displayed. It is therefore assumed that in one unit the display panel B is now placed on the carrier on the front right side and the display panel D is on the carrier on the rear left side.

Similarly, it is assumed that in the other unit, the display panel B' is placed on the carrier on the front left side and the display panel D' is on the carrier on the rear right side. The remaining display panels are all assumed to be located on the respectivetransver- sal guide passages, and are placed in the wait condition. After the elapse of a certain time interval which is controlled by the timer, the display panels B and B' are moved backward behind the front display side, followed by the succeeding display panels A and A', which travel a distance equal to their widths toward the left-hand and right-hand sides, respectively, as indicated by arrows 29 and 30 in Figure 1.

Then, the next succeeding display panels E and E' are appearing on the front display side. At the end of this cycle, the display panels A, E, E' and A' have appeared on the front display side while the display panels B and B' have move of to the respective positions previously assumed by the display panel C and C', which in turn have moved to the respective positions that had previously been assumed by the display panels D and D'. This completes one cycle.

The succeeding cycles are performed in the abovedescribed sequence. At any time during each cycle of the operation, four display panels are always placed on the front display side, and the presentation of the display panels occur at each time interval previously set by the timer.

Referring now to Figures 7 to 9 and Figure 3, the operational sequence in which the apparatus is to be operated to cause the above described movement of the individual display panels. In the foregoing description regarding the movement of the display panels, two units have been employed in which four display panels are to be presented on the display side. In the following description, it is also assumed that two units are employed, but as the operation for both the units is the same and for the simplicity of the explanation, the description is limited to the operation of one unit. It therefore should be understood that the description also applies to the other unit. The unit shown in Figures 3, and Figures 7 to 9 corresponds to the right side unit in Figure 2. In Figure 9,the transversal movement of the display panel B behind the display side as described earlier in connection with Figure 2 is allowed by causing the individual preceding display panels 7 to be moved down along the guide passage 14, 14a in the direction of an arrow 34. This movement is accomplished by starting the motor 21 which causes the rotary shaft 16b to rotate in the direction of an arrow 35 in Figure 7 and thus causing the hook lift cams 19, 19a secured to the shaft 16 to be rotated in the same direction.That is, the operation of the hook lift cams permits one display panel located nearest to the rear side carrier 8a to be transferred from the guide passage 14, 14a onto the hook bracket 11 a. In the meantime, the hook bracket 11 on the other carrier 8 is located to face the guide passage 15, 15a in Figure 3, and the motor 21a is started, causing the associated rotary shaft 1 6c to rotate in the direction of an arrow 36 which in turn rotates its associated hook lift cams 20, 20a in the same direction. Similarly, the operation of the hook lift cams permits a display panel located the nearest to the carrier to be transferred from the guide passage 15, 15a onto the hook bracket 11.Referring back to Figure 2, the display panel B has now moved backward, and the following display panel A has also moved to the position in which the panel is being permitted to move in the lateral direction. Then, the motor 28 is started, driving the pulley 4e for rotation in the direction of an arrow 37 in Figure 9 by way of the reduction gears 24. The rotation of the pulley 4c drives the belt 3 to travel in the direction of arrows 38 and 39, so that the carriers 8 and 8a with the display panels 7 on the hook brackets 11 and 1 la travel and are stopped at the respective positions as indicated in Figure 3. The stop of the carriers is accomplished when the carrier 8a contacts the limit switch 45. This is illustrated by referring back to Figure 2.The display panel B has now moved backward to the position previously assumed by the display panel C, which has moved to the position previously assumed by the display panel D. The display panel A has now moved to the position that had previously been assumed by the display panel B. Then, the motors 21 and 21a are started, causing the respective rotary shafts 1 6b and 1 6c which in turn rotate the corresponding pulleys 22 and 22a. The rotation of the pulleys 22 and 22a is thus transmitted by way of the belts 23 and 23a to the respective pulleys 22b and 22c.The rotary shafts 16, 16a associated with the pulleys 22b and 22c are thus rotated in the direction of an arrows 40 and 41 in Figure 7, causing the associated respective push-forward cams 17, 17a and 18, 1 boa to rotate so that the display panels on the carriers 8 and 8a can be disengaged from the hook brackets 11 and 11 a and transferred onto the respective guide passages 15, 15a and 14, 14a. When the display panels have thus been transferred, the motor 28 is started, causing the pulley 4cto rotate in the direction of an arrow 42 in Figure 9 by way of the reduction gears 24.The rotation of the pulley 4c drives the belt 3 to travel in the direction of arrows 43 and 44 in Figure 9, so that the carriers 8 and 8a travel and are stopped by the limit switch on the other side.

At the original or initial positions where the carriers are thus stopped, their respective hook brackets 11 and 11 a are now located to face the corresponding guide passages 15, 15a and 14, 14a.

In the above-described embodiment, the pushforward cam assembly is employed as a pushforward device that disengage a display panel from a carrier, and the lift-up cam assembly is employed as a lifting device which is capable of engaging a display panel with a carrier. The positive associative operation between the two different cam assemblies is provided by a single motor 21 or 21a. The push forward device may have any varied form other than the push forward cam assembly, such as a fluidly operated piston. In any way, it is possible to employ any appropriate means if it can provide the lock releasing function between the display panel and carrier.Similarly, the hook lift device may be implemented by any other means that wiil provide the function of transferring a display panel onto the hooked bracket 11, 1 1a on the carrier and engaging them. The rubber coating on the hooked portions 11, 11 a which has been described in the shown embodiment may be eliminated.

For applications of the apparatus shown in Figure 3 according to the present invention, a single unit or a combination of several units may be employed. A single unit can accommodate three or more display panels. If three display panels are mounted, two display members can be presented at any time on the display side, and each display member can be presented two times in two different positions.

Figures 4 to 6 show an application in which a single unit is used. Figures 7 to 9 illustrate the internal arrangement of a greater number of display panels in a single unit.

As it has fully been described, the present invention provides several advantages over the prior art devices of a similar type. Every display panel can be presented two times in two different positions as viewed from the outside, each time the display panels change their respective positions at the end of each display cycle. The change in the position of each display panel on the display side for two cyclic time periods can effectively attract the attention of the viewers. This enhances the advertising effect by focusing the viewers' attention upon the peculiar movement of the display panels.

The present invention has been described with reference to the particular embodiment in which the front side provides a display side. However, the present invention can provide for the possibilities of making both front and rear sides the display sides, if a display panel is designed to provide front and back advertisement faces.

Although the present invention has been described with reference to the several preferred embodiment therefore, it should be understood that various changes and modifications may be made without departing from the spirit and scope of the invention.

Claims (5)

1. An automatic advertisement display apparatus which includes a plurality of individual display members of a generally rectangular shape in the form of a panel, frame, or the like so that each of the display members can be presented two times in different positions during the two succeeding display cycles, comprising:: a casing having a front display side and a rear side; lateral transport means for causing the display members to travel a distance of their width in parallel with said front display and rear sides, said lateral transport means including two parallel conveying means running in the opposed directions; transversal transport means interposed between said two parallel conveying means for causing the display members to travel in a direction perpendicular to said front display side or rear side, said transversal transport means including two parallel conveying means on the opposite sides of said lateral transport means and having the additional function of storing the display members until they again appear on said front display side;; pushing forward means on one side between said lateral transport means and said transversal transport means, for pushing a display member forward so that it can travel onto said transversal transport means; and lifting means on the other side between said lateral transport means and said transversal transport means, for lifting a display member up so it can engage said lateral transport means.

2. An automatic advertisement display apparatus as defined in Claim 1, wherein said lateral transport means includes an endless or circular belt arranged to provide a generally rectangular form in a horizontal plane and a plurality of carrier means secured to said belt for carrying the display members.

3. An automatic advertisement display apparatus as defined in Claim 1, wherein at least two display members can be presented at one time on the front display side.

4. An automatic advertisement display apparatus as defined in Claim 1, wherein said pushingforward means comprises a pair of push cams.

5. An automatic advertisement display apparatus as defined in Claim 1, wherein said lifting means comprises a pair of hook lift cams.