One of the adornments placed over a Torah scroll are the Rimonim (lit. “pomegranates”) , in Morocco called Tapuhim (lit. “apples”) , which are bell-like objects that fit over the upper rollers and which jingle when shaken. Rimonim are not merely decorations but have a Halachic implication as well. The Bet Yosef (Y.D. § 282), citing Rabbenu Manoah, says that if someone so much as hears the movement of a Sefer Torah, one must rise in its honor. As such, the Rimonim are placed on the scrolls so as to alert those nearby to stand when the Torah is being held or moved.
Another implication is the use of Rimonim on Shabbat. The Taz (Y.D., 282:2) says that since there is a prohibition of playing musical instruments on Shabbat, Torah scrolls with Rimonim should not be taken out on Shabbat. The Magen Avraham (O.H. 38:1) disagrees and says that the jingling of the Rimonim is not akin to the playing of an instrument that our Sages referred to. The Halacha follows the Mishna Berura (M.B., O.H. 338:6) which permits using Rimonim on Shabbat, and this is our custom.
Beyond serving a decorative and a practical role, there is Kabbalistic significance to the Rimonim. The opinion of the Zohar (Yitro 88b) is that the Rimonim symbolize the two crowns that are taken from the Kabbalistic attribute of Tiferet (lit. “spleandor”) down to this world. The Arizal (Pri Etz Haim, Sha’ar Keriat Sefer Torah, ch. 1) also discusses at length the deep Kabbalistic secrets of the Rimonim and the importance of placing them on the rollers. Indeed, Rabbi Ben Zion Abba Shaul (Shivat Zion, vol. II, § 132) explains that it is worthy to pay for the Mitzvah of placing the Rimonim onto the Torah scroll. It should be noted that this Mitzvah applies specifically to when the Torah is removed from the Hechal. Therefore, it is proper to remove the Rimonim when the Sefer Torah is returned to the Hechal such that they can be placed back on when the Torah is removed in the future. This explains the Moroccan custom that the Rimonim are specifically removed from the Sifrei Torah before entering the arc , this way they are specifically put on the sefer torah when we take them out. Furthermore, it is customary to accord this honor to children to symbolize that they are accepting the crown of Torah.
Tangentially, another honor accorded to congregants is that of holding the Sefer Torah once it has been removed from the Hechal. Holding the Torah scroll is beneficial in rectifying specifically the sin of lewdness. In the Ben Ish Hai’s book of special prayers (Leshon Hachamim), there is a special prayer that should be recited while one hold the Sefer Torah so as to achieve atonement for any immoral acts or thoughts one may have had.
Summary: The jingling of the Rimonim helps alert congregants to stand in honor of the Torah and they are permitted on Shabbat.